2021 Summer Collaboration Meeting

9 Aug 2021, 07:00 → 13 Aug 2021, 15:00 America/Los_Angeles

The 13th in the series of twice-yearly CMB-S4 workshops will focus on continuing the development of the broadest possible CMB-S4 science case, including in conjunction with other experiments and observatories. It will be a fully online meeting open to CMB-S4 members and non-members alike.

Please familiarize yourself with the meeting code of conduct (linked below) and respect it in all venues.

Connect to the meeting using the zoom app (version 5.3 or later), set your name to "First Last (preferred pronouns)", and mute your microphone. To ask a question please raise your hand or post it to the chat.

The workshop will include:

• Social time before and after each day's session in gather.town, including career/networking and EPO gatherings
• A session on "Creating Communities of Care" followed by an open discussion with our new Equity, Diversity & Inclusion committee
• A poster session repeated late Tuesday and early Friday
• A closed Junior member session
• A "Teen Jeopardy" EPO event

The core of the workshop will be the 9 science themes, each of which will include a plenary introduction, an extended parallel session, and a plenary summary report. The themes and their conveners are:

Synergies of Large Scale Structure Surveys with CMB-S4 (Andrina Nicola & Emmanuel Schaan)

We will discuss what can only be learned from joint analyses of CMB-S4 and contemporaneous LSS observations at all wavelengths. We will review the landscape of LSS spectroscopic surveys (eg, MegaMapper, Mauna Kea Spectroscopic Explorer), photometric surveys (Rubin, Euclid, Roman), intensity mapping experiments (eg, PUMA) and more. We will point out the cosmology, astrophysics and systematics which benefit most from these synergies (eg, Nx2pt, CMB lensing tomography, kSZ, galaxy lensing calibration, cluster cosmology).

Gravitational Waves (Raphael Flauger & Sarah Shandera)

Gravitational waves provide an unobstructed view of the dynamics of the universe through cosmic history.  Measurements of the CMB, including T, E, and B-modes, inform our understanding of both primordial gravitational waves and potentially sources that could be observed by direct measurements.  This session will consider observables beyond the tensor-to-scalar ratio, and will explore the complementarity of these probes as well as opportunities to make more direct contact between these communities.

The Time-Varying mm-Wave Sky (Gregg Hallinan & Anna Ho)

Recent results from ACT & SPT have demonstrated that CMB experiments can track the dynamic mm-wave sky, with detections of flaring stars and strongly varying extragalactic sources. Searches are underway for new planets in our solar system and GRBs, and there are opportunities for multi-messenger events, such as high-energy neutrinos or gravitational waves. This session will review recent transient science at millimeter wavelengths, with a focus on gamma-ray bursts and stellar flares. We will use these results to discuss what can be achieved with the CMB-S4 surveys.

Backlighting the Baryons with CMB-S4 (Simone Ferraro &  Alexie Leauthaud)

CMB-S4 will fully determine the gas thermodynamics in unexplored environments: the outskirts of low-mass, high-redshift halos. We will discuss the complementarity of CMB (kSZ, tSZ and lensing) with other probes (eg, X rays and QSO absorption lines), and what we they will tell us about galaxy formation, cosmological hydro simulations and baryonic effects in weak lensing.

Messengers from the Early Universe (Nathaniel Craig & Joel Meyers)

Little is known about the history of the universe between the end of inflation and the beginning of big bang nucleosynthesis.  It is during this period that the dark matter and the baryon asymmetry were produced, the origin of each being enormous unsolved problems in astroparticle physics. It may even be important for the origin of the Higgs mass or the strong CP problem.  Relics from this era will leave signatures in both the primary CMB and secondaries, like CMB lensing, often appearing as corrections to Neff and/or the sum of the neutrino masses.  In this session, we will explore the myriad of connections between problems in comic history, fundamental physics and astrophysics that can be addressed through precision measurements of the CMB.

The Galactic ISM in 3D (Brandon Hensley & Gina Panopoulou)

CMB-S4 will make sensitive, high-resolution measurements of the Galactic polarized dust and synchrotron emission over large areas of the sky. We will discuss how these data can probe gas, dust, and magnetic fields over a range of scales, with particular emphasis on synergies with other datasets that enable a three-dimensional view.

From the Dark Ages to Reionization with CMB-S4 (Marcelo Alvarez & Zhilei Xu)

The history of the Universe between recombination and reionization remains mostly an unexplored territory. Reionization leaves imprints on the CMB temperature and polarization (mean optical depth, kSZ, patchy tau). In this session, we will discuss methods of measuring these effects directly from CMB and using cross-correlations utilizing the synergies with galaxy surveys or line intensity mapping. We will also discuss what these measurements tell us about the physics of reionization.

Astrophysics and Cosmology with Galaxy Clusters (Srinivasan Raghunathan &  Heidi Wu)

CMB-S4 will make a giant leap in the field of cluster astrophysics and cosmology by producing a mass-limited catalogue containing 10^5 clusters with close to 1000 distant clusters out to z~>2. In this session we will discuss how these detections and the synergy of CMB-S4 with optical/X-ray surveys such as DES, LSST, eROSITA and the future Lynx/Athena missions will help us understand the physics of the intracluster medium and constrain the model of structure formation in the Universe.

Snowmass Planning and CMB-S4 (Clarence Chang & Scott Dodelson)

Snowmass is a planning exercise for the particle physics community to identify the key questions and opportunities that will inform the strategic plan for the field in the coming decades.  CMB-S4 is the definitive ground-based CMB survey that will allow for deep cosmological insights into particle physics.  This session will bring together Snowmass organizers and members of the CMB-S4 community to identify the opportunities for synergy and cross-collaboration among the communities.

Code of Conduct

Gather.Town Guide

Monday, 9 August

07:00 → 08:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

08:00 → 09:25 Plenary

Collaboration Update (google slides)

Collaboration Update.pdf

Notes

08:00 Welcome & Logistics

Speaker: Julian Borrill (Lawrence Berkeley National Laboratory & UC Berkeley)

Welcome & Logistics

Welcome & Logistics.pdf

08:15 Collaboration Update

Speakers: Abigail Crites (University of Toronto;Dunlap Institute) , Christian Reichardt (University of Melbourne) , Colin Bischoff (University of Cincinnati) , Darcy Barron (University of New Mexico) , Gregory Tucker (Brown University) , Joel Meyers (Southern Methodist University;) , John Carlstrom (University of Chicago;Argonne National Laboratory) , Julian Borrill (Lawrence Berkeley National Laboratory & UC Berkeley) , Kevin Huffenberger (Florida State University) , Lindsey Bleem (Argonne National Laboratory & KICP) , Lloyd Knox (UC Davis) , Renee Hlozek (University of Toronto) , Sara Simon (Fermilab)

Collaboration update (google slides)

Collaboration Update.pdf

09:25 → 10:00 Break

10:00 → 10:50 Plenary

Collaboration Update (google slides)

Collaboration Update.pdf

Notes

10:00 Poster Fireslides

Speaker: Dr Maria Salatino (Stanford University;)

poster_fireslides_merged.pdf

10:05 Project Update

Speaker: John Corlett (Lawrence Berkeley National Laboratory)

Project Update

Project Update.pdf

10:40 Conference Photo

10:50 → 11:10 Break

11:10 → 13:10 EDI Event: Creating Communities of Care

Learn how your individual actions, attitudes and behaviors can cultivate cultures of inclusion in the groups and organizations you join. This workshop session will cover principles of effective allyship, developing resiliency for ongoing diversity work, and skills for bystander intervention in the face of bias.

Notes/References:
- BIPOC: Black, Indigenous, & People of Color
- PBS documentary "Race: the Power of an Illusion", episode 3 on housing
- “Unpacking the Invisible Knapsack” by Peggy McIntosh

Speakers: Tiana Pyer-Pereira, Vickie Sides (U Chicago Staff)

Allyship, Resilience and Bystander Intervenion for Bias CMB-S4 2021.pdf

Dr Sue article, including taxonomy of microaggressions

Dr Sue video

When Addressing Anti-Racism: Not Just What, But How

13:10 → 13:30 Break

13:30 → 14:00 Discussion Session With EDI Committee

Speaker: Sara Simon (Fermilab)

14:00 → 15:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

Tuesday, 10 August

07:00 → 08:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

08:00 → 09:15 Plenary

Collaboration Update (google slides)

Collaboration Update.pdf

Notes

08:00 EPO: Karsh STEM Scholars Program

Ron H. Smith is the Director of the Howard University Karsh STEM Scholars Program. The Karsh STEM Scholars Program currently supports 122 STEM Scholars throughout their academic journey, with the goal of the Scholars receiving a Ph.D. in a STEM field. Students start in the program during their undergraduate years and continue through the completion of their graduate degree. In this session, Mr.
Smith will highlight this award-winning program by sharing the vision for the program and how it developed. He will also highlight the prestigious accomplishments of the program’s Scholars. 

The Howard University Karsh STEM Scholars Program received the 2020 Inspiring Programs in STEM Award from INSIGHT Into Diversity magazine, the largest and oldest diversity and inclusion publication in higher education. This Award honors colleges and universities that encourage and assist students from underrepresented groups in their pursuit of careers in the
fields of science, technology, engineering, and mathematics.

Speakers: Juliet Crowell (University of Chicago;) , Ronald Smith (Howard University)

2021 Summer Collaboration Meeting_RSmith_Presentation.pdf

2021 Summer Collaboration Meeting_RSmith_Presentation.pptx

EPO Session_STEMPrograms_81221.docx

09:00 Fireslides

Speaker: Matthaeus Leitner (Lawrence Berkeley National Laboratory)

Fireslides-Collaboration-Summer2021.pdf

09:15 → 09:45 Junior Member Closed Session

A closed session for junior members and non-members only convened by the Governing Board postdoctoral representative, Ben Schmitt.

See videoconference room link for connection details.

Speaker: Benjamin Schmitt (Harvard University;)

09:15 → 09:45 Senior Member Feedback Session

This session will be held in parallel with the closed junior member feedback session. This is not a closed session, and all attendees are welcome to join.

We will discuss ideas for what kinds of programs we can or should support as a growing collaboration, and how to get more junior and senior members involved in these efforts.

Potential discussion topics include:
- How and when to start a mentorship program
- How to support people writing proposals for CMB-S4 related funding
- How to get more people engaged in CMB-S4 governance
- How to support members applying for faculty positions

Hosted by:
Darcy Barron (chair of Junior Scientist Advancement Committee)
Lindsey Bleem (chair of Governing Board)
Sara Simon (chair of Equity, Diversity, and Inclusion committee)

Speakers: Darcy Barron (University of New Mexico) , Lindsey Bleem (Argonne National Laboratory & KICP) , Sara Simon (Fermilab)

09:45 → 10:05 Break

10:05 → 10:20 Synergies of Large Scale Structure Surveys with CMB-S4: Plenary Introduction

Conveners: Andrina Nicola (Princeton University) , Emmanuel Schaan (Lawrence Berkeley National Laboratory;)

Notes

Notes and discussions

 

 

---

Anze Slosar

 

Notes:

• Surveys interacting with S4: live on k-plane

• Taxonomy of surveys: 

  • projected tracers (CMB lensing, WL, GC): low k_perp, no k_par 

  • Spec surveys: all plane

  • Foregrounded: no kpar

• Cross-correlation: overlap in k modes

• Proj: no redshift specificity

• Spectro: full 3D, xcorr with CMB only small slice, high SN

• Foregrounded: no kpar, 21cm, do not overlap with CMB lensing (projected)

• Redshift specificity helps a lot - 3x2pt, CMB lensing

• Higher order stats: allow you to combine things that don’t necessarily overlap on k plane

• Field reconstructions to recover lost k modes, e.g. 21cm, reconstruct initial modes

• CMB: lensing (complete, sample-variance cancelation), tSZ/kSZ, ISW, moving lens, patchy reionization - xcorr with 21cm

• Combine kSZ ML: Hotinli et al.

 

Questions:

• Most promising avenue for CMB x 21cm?
  → Probably tidal reconstruction or lensing reconstruction

 

 

---

Utkarsh Giri

 

Notes:

• kSZ: CMB photon scattering by moving electrons

• Sec. anisotropy prop to velocity and electron density

• Fixed realization of vr produces non-vanishing correlation between deltag and T -> reconstruct velocity mode

• Vr probes large scale cosmological modes, on large scales: cosmological fields linearly related, on large scales - vr reconstruction noise smaller than GC shot noise

• Application: fNL, sample variance cancelation due to additional tracers

• Use vr as additional tracer -> strong fNL constraints

• Question: rely on linear noise models, nonlinearities?

• Use sims to investigate noise assumptions: 2-3 times larger noise for reconstructions due to nonlinear noises (similar to CMB lensing biases) N1, N3/2

• Noises can be captured analytically

• Use sims to check SVC - 

 

Questions:

 

Blake: is it obvious why the N3/2 bias is a lot bigger than the N1? (Sorry if I missed this.) 

Manu: How important is accurate modeling of N32?

 

Colin: what sets the scale at which N3/2 peaks?

 

 

---

David Alonso

 

Notes:

• Projected tracers, e.g. LSST, tracers of matter fluctuations

• Focus on CMB lensing and WL, GC

• tSZ tomography: cross-correlate tSZ with clustering - constrain gas pressure / mass bias

• Cluster mass calibration - high-z clusters

• Tomography: reconstruct redshift dependence, Nx2pt

• Use tomography to constrain growth - break bias - growth degeneracy with CMB lensing

• Growth reconstruction: check probe consistency, consistency with LCDM

  • Two data sets: DECALS, KiDS / DES / Planck

  • Decouple growth from background - growth spline with nodes

  • S8(z): data comb gives evidence of lower growth at 0.2<z<0.6 -> driven by shear

  • Need CMB lensing for high-z

  • LCDM good fit with lower S8

• Systematics:

  • Photoz uncertainties: analytic marg, self-calib, CMB x less sensitive

  • Shear calibration:

  • Galaxy bias: hybrid EFT

 

Questions:

 

 

---

Alex Krolewski

 

Notes:

• Improve on CMB lensing auto with GC - growth of structure, brings in galaxy bias -> need all probes

• Related to S8 tension

• Use CMB lensing as xcheck of optical lensing

• Pick galaxy sample with high S/N

  • High z - overlap with lensing kernel

  • Angular coverage

  • WISE: infrared galaxy survey: all-sky, gals with old stellar pops can be easier to detect in WISE

• Three galaxy samples: blue, red, green z~0.6 - z~1.5

• Need to remove stars using GAIA - contamination left 1%

• Redshift distribution: no photoz - > do cross-correlation redshifts with specs, measure n(z) and bias evolution, so just include measured relations in theory

• Theory: linear + HO bias (dominated by linear modes), allows fix cosmo & HO bias

• Tests on mocks, calibration of scales used, lmax~250-300

• Redshift uncertainty: run sep. chains for all nz realizations -> full shape marg.

• Results: samples consistent, 2.6sigma tension with Planck in S8

 

Questions:

David A.: Can you say a bit more about the N(z) marginalization using clustering redshifts? E.g. do you need to worry about the fact that the measurements allow for negative values?

Blake: If I recall right, DES obtained the same S8-only constraint but did not report tension with Planck when considering the full posterior. Could you remind me how you obtained the 2.6sigma tension number and could a similar effect operate here?

 

 

---

Yan-Chuan Cai

 

Notes:

• ISW and CMB lensing around substructures

• ISW and CMB lensing: Sourced by same late-time grav potential 

• ISW: probe of accelerated expansion - time-varying potentials

• Photons in voids: cold-spot in CMB, photons in clusters: hot spot

• Usually: cross-correlations between primary CMB and LSS tracers (e.g. lensing)

  • Joint measurements of GC, CMB lensing, ISW

• Why superstructures?

  • Look at generalization of cluster cosmology, peak counts, etc.

  • Beyond 2pt

  • Beyond GR - different behaviour in high/low density regions

  • Granett et al., 2008: amplitude of stacked CMB temperature high compared to LCDM expectation

  • Question: what is the cause for this?

• Repeat analysis using DESI legacy survey 

  • reduce sample variance

  • No detection for temperature imprints from supervoids 

 

Questions:

Jia: why is there no lack of signal for void (but it is there for clusters..)? I.e.why “lensing is low” is not impacting void? Answer: could be related to photo-z bias, or something physical (e.g. neutrino free-streaming) but no definitive answer.

David A.: there was a recent paper measuring a negative ISW from voids at very high redshifts from QSOs. Do you have any thoughts on that? (this one)

Yan-Chuan Cai: Yes. I think the statistical significance isn’t very high,less than 3sigma I think, similar to many other analyses. It would be great to have more volume to beat down the variance.

 

---

Leander Thiele

 

Notes:

• NNs to map N-bodies to baryons: CNN / DeepSet

• Predict baryonic fields from DM only - baryons local, i.e. use local ML approach

• Usage:

  • Rapidly generate sims

  • Interpret trained model and learn about astro

• CNN:

  • DM -> pe, ne

  • Use CNN on 3D field, redshift zero

  • Semianalytic models

  • Main problem: sparsity, only small fraction of volume is interesting, overcome by biasing training sample using zoom-ins

  • Electron pressure spans large dynamic range (input trafos, semi-analytic model)

  • Small scales well fit, large scales better than models, projection improves performance

• DeepSet:

  • Concentrate on massive halos -> no transl symmetry

  • CNNs not best approach: spend lot of resource on empty regions, poor interpretability

  • Idea: can we use simulations representation to train NN? - DeepSet VAE

  • Restricted architecture improves on existing models

 

Questions:

• Interpolate between baryonic feedback models? Train on one sim and then do transfer learning on other sim

 

 

---

Jia Liu

 

Notes:

• Why sims? Test pipelines, systematics, astrophysics, covariance, modeling

• Why correlated? CMB foregrounds and LSS, not super useful for survey systematics because will be uncorrelated, but extragalactic, astrophysics syst will show up differently, input to train ML models

• Typical CMB sims: 2D, gravity only, CMB observables painted -> Sehgal, Stein

• Typical LSS sims: 2/3D, more cosmo, hydro/gravity only, curved/flat, smaller boxes

• Correlated sims need to accommodate both worlds

• current : run by experts in both areas

• Yuuki Omori: MultiDark Planck 2

• Roadmap:

  • Basis: gravity-only sims

  • Then send off to experts and paint on CMB / LSS observables

  • Coordination!

  • How to get gravity-only sims: fast full-sky lightcone (e.g. COLA, FastPM)

  • Challenges: computing, storage, requirements, maintenance, personnel

 

Questions:

 

 

---

Dongwon ‘DW’ Han

 

Notes:

• Need correlated sims: high-res, multi-frequency, need NG info

• Computationally expensive -> use DL

• mmDL: CMB kappa -> NG kappa, kSZ, tSZ, CIB, radio + lensed TUQ

• Network:

  • Data augmentation, not enough sims

  • Conversion / prediction

  • NG restoration step

• Results:

  • Reproduce source counts, power spectra, cross-correlations, bispectra, trispectra (CMB lensing biases)

  • Network can recover correlations between large and small scales even though trained on small patches

  • Variance in sims comparable to Knox

• Sims available publicly

• Allow mass-production of independent full-sky realizations

• Fast: forward-modeling

• Future:

  • Fixed cosmology - CAMELS?

  • Missing associated catalog - extension to create catalogs

  • Can we use network to learn optimal summary stats?

 

Questions:

 

10:05 Synergies of Large Scale Structure Surveys with CMB-S4: Plenary Introduction

Speaker: Emmanuel Schaan (Lawrence Berkeley National Laboratory;)

schaan_s4_20210810.pdf

10:20 → 10:35 Messengers from the Early Universe: Plenary Introduction

Conveners: Joel Meyers (Southern Methodist University;) , Nathaniel Craig (UC Santa Barbara)

Notes

10:20 Messengers from the Early Universe: Plenary Introduction

Speaker: Joel Meyers (Southern Methodist University;)

Messengers from the Early Universe with CMB-S4 - Meyers.pdf

10:35 → 10:50 The Time-Varying mm-Wave Sky: Plenary Introduction

Conveners: Anna Ho (UC;LBL) , Gregg Hallinan (Caltech)

cmbs4-intro-plenary-final.pdf

cmbs4-recap.pdf

Notes

10:35 The Time-Varying mm-Wave Sky: Plenary Introduction

10 min talk + 5 min Q&A

Speaker: Anna Ho (UC;LBL)

cmbs4-intro-plenary-final.pdf

10:50 → 11:10 Break

11:10 → 14:00 Messengers from the Early Universe: Parallel

Conveners: Joel Meyers (Southern Methodist University;) , Nathaniel Craig (UC Santa Barbara)

Notes

11:10 Cosmological Constraints on Light (but Massive) Relics

Speaker: Weishuang Xu (Harvard)

LiMRs_8min.pdf

11:20 CMB S4: Gatekeeper of Dark Complexity

CMB measurements have unique and almost completely model-independent sensitivity to new light degrees of freedom. As a result, whole classes of dark sectors and dark matter models should produce a signal at CMB S4. Non-detection would severely constrain the space of possible solutions for fundamental puzzles like the nature of dark matter or the hierarchy problem. Positive detection would confirm physics beyond the Standard Model and lend strong motivation to non-minimal dark sectors, and I will outline the variety of exciting new astrophysical and cosmological signals that could be generated by such scenarios: formation of mirror stars and their signals in optical, X-ray, gravitational lensing or gravitational wave observations; direct detection of atomic dark matter with dark plasma screening effects in terrestrial experiments or stellar cooling; and combining full MHD N-body simulations of atomic dark matter with measurements of galactic structure to determine the forces active in the dark sector.

Speaker: David Curtin (University of Toronto)

davidcurtin_darkcomplexity_CMB_CMBS4meeting_10aug2021_15m.pdf

11:40 CMB and BBN constraints on light thermally coupled WIMPs

Speaker: Rui An (University of Southern California)

CMB-S4 meeting.pdf

11:50 Discussion

Speakers: Joel Meyers (Southern Methodist University;) , Nathaniel Craig (UC Santa Barbara)

12:25 Mid-Parallel Break

12:45 Modulating fields and the CMB

Speaker: Prof. JiJi Fan (Brown University)

cmb-s4_Fan.pdf

13:05 Probing Axion Couplings to Matter with N_{eff} Measurements

Speaker: Benjamin Wallisch (UC San Diego & Institute for Advanced Study)

cmb-s4_wallisch.pdf

13:15 The Cosmic Axion Background

In this talk I will show that we can detect relativistic axions that are a relic of the early Universe with instruments searching for axion dark matter. I will outline several forms such a cosmic axion background could take, demonstrate how the CaB would appear at an axion haloscope, and explain why current analyses would discard any emerging signal as a background.

Speaker: Dr Nicholas Rodd (CERN)

CosmicAxionBackground.pdf

13:35 Discussion

Speakers: Joel Meyers (Southern Methodist University;) , Nathaniel Craig (UC Santa Barbara)

11:10 → 14:00 Synergies of Large Scale Structure Surveys with CMB-S4: Parallel

Conveners: Andrina Nicola (Princeton University) , Emmanuel Schaan (Lawrence Berkeley National Laboratory;)

Notes

Notes and discussions

 

 

---

Anze Slosar

 

Notes:

• Surveys interacting with S4: live on k-plane

• Taxonomy of surveys: 

  • projected tracers (CMB lensing, WL, GC): low k_perp, no k_par 

  • Spec surveys: all plane

  • Foregrounded: no kpar

• Cross-correlation: overlap in k modes

• Proj: no redshift specificity

• Spectro: full 3D, xcorr with CMB only small slice, high SN

• Foregrounded: no kpar, 21cm, do not overlap with CMB lensing (projected)

• Redshift specificity helps a lot - 3x2pt, CMB lensing

• Higher order stats: allow you to combine things that don’t necessarily overlap on k plane

• Field reconstructions to recover lost k modes, e.g. 21cm, reconstruct initial modes

• CMB: lensing (complete, sample-variance cancelation), tSZ/kSZ, ISW, moving lens, patchy reionization - xcorr with 21cm

• Combine kSZ ML: Hotinli et al.

 

Questions:

• Most promising avenue for CMB x 21cm?
  → Probably tidal reconstruction or lensing reconstruction

 

 

---

Utkarsh Giri

 

Notes:

• kSZ: CMB photon scattering by moving electrons

• Sec. anisotropy prop to velocity and electron density

• Fixed realization of vr produces non-vanishing correlation between deltag and T -> reconstruct velocity mode

• Vr probes large scale cosmological modes, on large scales: cosmological fields linearly related, on large scales - vr reconstruction noise smaller than GC shot noise

• Application: fNL, sample variance cancelation due to additional tracers

• Use vr as additional tracer -> strong fNL constraints

• Question: rely on linear noise models, nonlinearities?

• Use sims to investigate noise assumptions: 2-3 times larger noise for reconstructions due to nonlinear noises (similar to CMB lensing biases) N1, N3/2

• Noises can be captured analytically

• Use sims to check SVC - 

 

Questions:

 

Blake: is it obvious why the N3/2 bias is a lot bigger than the N1? (Sorry if I missed this.) 

Manu: How important is accurate modeling of N32?

 

Colin: what sets the scale at which N3/2 peaks?

 

 

---

David Alonso

 

Notes:

• Projected tracers, e.g. LSST, tracers of matter fluctuations

• Focus on CMB lensing and WL, GC

• tSZ tomography: cross-correlate tSZ with clustering - constrain gas pressure / mass bias

• Cluster mass calibration - high-z clusters

• Tomography: reconstruct redshift dependence, Nx2pt

• Use tomography to constrain growth - break bias - growth degeneracy with CMB lensing

• Growth reconstruction: check probe consistency, consistency with LCDM

  • Two data sets: DECALS, KiDS / DES / Planck

  • Decouple growth from background - growth spline with nodes

  • S8(z): data comb gives evidence of lower growth at 0.2<z<0.6 -> driven by shear

  • Need CMB lensing for high-z

  • LCDM good fit with lower S8

• Systematics:

  • Photoz uncertainties: analytic marg, self-calib, CMB x less sensitive

  • Shear calibration:

  • Galaxy bias: hybrid EFT

 

Questions:

 

 

---

Alex Krolewski

 

Notes:

• Improve on CMB lensing auto with GC - growth of structure, brings in galaxy bias -> need all probes

• Related to S8 tension

• Use CMB lensing as xcheck of optical lensing

• Pick galaxy sample with high S/N

  • High z - overlap with lensing kernel

  • Angular coverage

  • WISE: infrared galaxy survey: all-sky, gals with old stellar pops can be easier to detect in WISE

• Three galaxy samples: blue, red, green z~0.6 - z~1.5

• Need to remove stars using GAIA - contamination left 1%

• Redshift distribution: no photoz - > do cross-correlation redshifts with specs, measure n(z) and bias evolution, so just include measured relations in theory

• Theory: linear + HO bias (dominated by linear modes), allows fix cosmo & HO bias

• Tests on mocks, calibration of scales used, lmax~250-300

• Redshift uncertainty: run sep. chains for all nz realizations -> full shape marg.

• Results: samples consistent, 2.6sigma tension with Planck in S8

 

Questions:

David A.: Can you say a bit more about the N(z) marginalization using clustering redshifts? E.g. do you need to worry about the fact that the measurements allow for negative values?

Blake: If I recall right, DES obtained the same S8-only constraint but did not report tension with Planck when considering the full posterior. Could you remind me how you obtained the 2.6sigma tension number and could a similar effect operate here?

 

 

---

Yan-Chuan Cai

 

Notes:

• ISW and CMB lensing around substructures

• ISW and CMB lensing: Sourced by same late-time grav potential 

• ISW: probe of accelerated expansion - time-varying potentials

• Photons in voids: cold-spot in CMB, photons in clusters: hot spot

• Usually: cross-correlations between primary CMB and LSS tracers (e.g. lensing)

  • Joint measurements of GC, CMB lensing, ISW

• Why superstructures?

  • Look at generalization of cluster cosmology, peak counts, etc.

  • Beyond 2pt

  • Beyond GR - different behaviour in high/low density regions

  • Granett et al., 2008: amplitude of stacked CMB temperature high compared to LCDM expectation

  • Question: what is the cause for this?

• Repeat analysis using DESI legacy survey 

  • reduce sample variance

  • No detection for temperature imprints from supervoids 

 

Questions:

Jia: why is there no lack of signal for void (but it is there for clusters..)? I.e.why “lensing is low” is not impacting void? Answer: could be related to photo-z bias, or something physical (e.g. neutrino free-streaming) but no definitive answer.

David A.: there was a recent paper measuring a negative ISW from voids at very high redshifts from QSOs. Do you have any thoughts on that? (this one)

Yan-Chuan Cai: Yes. I think the statistical significance isn’t very high,less than 3sigma I think, similar to many other analyses. It would be great to have more volume to beat down the variance.

 

---

Leander Thiele

 

Notes:

• NNs to map N-bodies to baryons: CNN / DeepSet

• Predict baryonic fields from DM only - baryons local, i.e. use local ML approach

• Usage:

  • Rapidly generate sims

  • Interpret trained model and learn about astro

• CNN:

  • DM -> pe, ne

  • Use CNN on 3D field, redshift zero

  • Semianalytic models

  • Main problem: sparsity, only small fraction of volume is interesting, overcome by biasing training sample using zoom-ins

  • Electron pressure spans large dynamic range (input trafos, semi-analytic model)

  • Small scales well fit, large scales better than models, projection improves performance

• DeepSet:

  • Concentrate on massive halos -> no transl symmetry

  • CNNs not best approach: spend lot of resource on empty regions, poor interpretability

  • Idea: can we use simulations representation to train NN? - DeepSet VAE

  • Restricted architecture improves on existing models

 

Questions:

• Interpolate between baryonic feedback models? Train on one sim and then do transfer learning on other sim

 

 

---

Jia Liu

 

Notes:

• Why sims? Test pipelines, systematics, astrophysics, covariance, modeling

• Why correlated? CMB foregrounds and LSS, not super useful for survey systematics because will be uncorrelated, but extragalactic, astrophysics syst will show up differently, input to train ML models

• Typical CMB sims: 2D, gravity only, CMB observables painted -> Sehgal, Stein

• Typical LSS sims: 2/3D, more cosmo, hydro/gravity only, curved/flat, smaller boxes

• Correlated sims need to accommodate both worlds

• current : run by experts in both areas

• Yuuki Omori: MultiDark Planck 2

• Roadmap:

  • Basis: gravity-only sims

  • Then send off to experts and paint on CMB / LSS observables

  • Coordination!

  • How to get gravity-only sims: fast full-sky lightcone (e.g. COLA, FastPM)

  • Challenges: computing, storage, requirements, maintenance, personnel

 

Questions:

 

 

---

Dongwon ‘DW’ Han

 

Notes:

• Need correlated sims: high-res, multi-frequency, need NG info

• Computationally expensive -> use DL

• mmDL: CMB kappa -> NG kappa, kSZ, tSZ, CIB, radio + lensed TUQ

• Network:

  • Data augmentation, not enough sims

  • Conversion / prediction

  • NG restoration step

• Results:

  • Reproduce source counts, power spectra, cross-correlations, bispectra, trispectra (CMB lensing biases)

  • Network can recover correlations between large and small scales even though trained on small patches

  • Variance in sims comparable to Knox

• Sims available publicly

• Allow mass-production of independent full-sky realizations

• Fast: forward-modeling

• Future:

  • Fixed cosmology - CAMELS?

  • Missing associated catalog - extension to create catalogs

  • Can we use network to learn optimal summary stats?

 

Questions:

 

11:10 Landscape of LSS surveys contemporary to CMB-S4

Speaker: Anze Slosar (Brookhaven National Laboratory;)

presentation

11:25 Non-Gaussianity from CMB-S4 kSZ & LSS

Speaker: Utkarsh Giri (Perimeter Institute for Theoretical Physics)

CMB-S4_Utkarsh.pdf

11:40 Cosmology from CMB-S4 lensing x LSS

Speaker: David Alonso (Oxford University;)

CMB-S4 x-correlations.pdf

Google slides

11:55 Cosmology from Planck lensing x unWISE

Speaker: Alex Krolewski (Lawrence Berkeley National Laboratory)

CMBS4_Talk.pdf

12:10 Higher Order Statistics for CMBxLSS

Speaker: Yan-Chuan Cai (University of Edinburgh)

Cai_CMBS4_summer2021.pdf

12:25 Mid-Parallel Break

12:45 Mapping Dark Matter to Sunyaev-Zel'dovich with Neural Networks

Speaker: Leander Thiele (Princeton University)

Mapping_DM_to_SZ_with_NNs_LeanderThiele.pdf

13:00 Correlated simulations for CMB and LSS: overview

Speaker: Jia Liu (UC Berkeley)

cmb-s4_lssxcmb_sims_jialiu.pdf

13:15 MillimeterDL: Deep Learning Simulations of the Microwave Sky

Speaker: Dongwon Han (Stony Brook University)

Han_mmDL_CMBS4v3.pdf

13:30 Discussion

CMB S4 synergies with LSS

11:10 → 14:00 The Time-Varying mm-Wave Sky: Parallel

Conveners: Anna Ho (UC;LBL) , Gregg Hallinan (Caltech)

cmbs4-intro-plenary-final.pdf

cmbs4-recap.pdf

Notes

11:10 Introduction

Speakers: Anna Ho (UC;LBL) , Prof. Joaquin Vieira (University of Illinois at Urbana-Champaign;)

11:15 GRBs 1: Observations of GRBs in the mm range

In this talk I will give a brief description of the gamma-ray burst phenomena, will introduce the different types of progenitors, and the model that defines the electromagnetic emission of GRBs. I will focus particularly on the emission in the millimetre range and place this into the context of CMB-S4, giving examples of what we may expect to gain through the observations performed by the new observatory.

Speaker: Antonio de Ugarte Postigo (IAA-CSIC)

mmGRBs_AdUP_compressed.pdf

11:35 GRBs 2: Millimeter Observations of Extragalactic Transients and Prospects for CMB-S4

The mm-band presents an exciting new discovery space for extragalactic transients, including supernovae, gamma-ray bursts, tidal disruption events, and fast & blue optical transients. I will set the stage via glimpses through the new window opened up by ALMA into the science of such transients, followed by prospects for their detection and characterization with upcoming CMB surveys.

Speaker: Tanmoy Laskar (University of Bath)

Laskar_2021_CMB-S4.pdf

11:55 Discussion

For GRB science, what do we need in terms of:
- Alert stream contents & timescale
- Additional technical infrastructure / data products

Do we benefit from a higher-cadence experiment from the Pole? (Higher depth, higher cadence, longer revisit time)

Speakers: Anna Ho (UC;LBL) , Joaquin Vieira (University of Illinois at Urbana-Champaign;)

12:25 Mid-Parallel Break

12:45 Introduction

• Review recent results from SPT & ACT
• Questions to bear in mind during the talks

Speakers: Anna Ho (UC;LBL) , Joaquin Vieira (University of Illinois at Urbana-Champaign;)

12:50 Stellar Flares 1: The Millimeter View of Stellar Flares

15 min talk + 5 min Q&A

Speaker: Meredith MacGregor (University of Colorado Boulder)

CMBS4_MacGregor.pdf

13:10 Stellar Flares 2: The Panchromatic View of Stellar Flares

Talk by Rachel Osten

Speaker: Rachel Osten (Space Telescope Science Institute)

Osten_CMB-S4talk.key

Osten_CMB-S4talk.pdf

13:30 Discussion

For stellar-flare science, what do we need in terms of:
- Alert stream contents & timescale
- Additional technical infrastructure / data products

Do we benefit from a higher-cadence experiment from the Pole? (Higher depth, higher cadence, longer revisit time)

Speakers: Anna Ho (UC;LBL) , Joaquin Vieira (University of Illinois at Urbana-Champaign;)

14:00 → 15:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

15:00 → 15:45 Poster Session in Gather.Town

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

Wednesday, 11 August

07:00 → 08:00 Gather.Town: Career/Networking

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

08:00 → 08:35 Synergies of Large Scale Structure Surveys with CMB-S4: Plenary Summary Report

Conveners: Andrina Nicola (Princeton University) , Emmanuel Schaan (Lawrence Berkeley National Laboratory;)

Notes

Notes and discussions

 

 

---

Anze Slosar

 

Notes:

• Surveys interacting with S4: live on k-plane

• Taxonomy of surveys: 

  • projected tracers (CMB lensing, WL, GC): low k_perp, no k_par 

  • Spec surveys: all plane

  • Foregrounded: no kpar

• Cross-correlation: overlap in k modes

• Proj: no redshift specificity

• Spectro: full 3D, xcorr with CMB only small slice, high SN

• Foregrounded: no kpar, 21cm, do not overlap with CMB lensing (projected)

• Redshift specificity helps a lot - 3x2pt, CMB lensing

• Higher order stats: allow you to combine things that don’t necessarily overlap on k plane

• Field reconstructions to recover lost k modes, e.g. 21cm, reconstruct initial modes

• CMB: lensing (complete, sample-variance cancelation), tSZ/kSZ, ISW, moving lens, patchy reionization - xcorr with 21cm

• Combine kSZ ML: Hotinli et al.

 

Questions:

• Most promising avenue for CMB x 21cm?
  → Probably tidal reconstruction or lensing reconstruction

 

 

---

Utkarsh Giri

 

Notes:

• kSZ: CMB photon scattering by moving electrons

• Sec. anisotropy prop to velocity and electron density

• Fixed realization of vr produces non-vanishing correlation between deltag and T -> reconstruct velocity mode

• Vr probes large scale cosmological modes, on large scales: cosmological fields linearly related, on large scales - vr reconstruction noise smaller than GC shot noise

• Application: fNL, sample variance cancelation due to additional tracers

• Use vr as additional tracer -> strong fNL constraints

• Question: rely on linear noise models, nonlinearities?

• Use sims to investigate noise assumptions: 2-3 times larger noise for reconstructions due to nonlinear noises (similar to CMB lensing biases) N1, N3/2

• Noises can be captured analytically

• Use sims to check SVC - 

 

Questions:

 

Blake: is it obvious why the N3/2 bias is a lot bigger than the N1? (Sorry if I missed this.) 

Manu: How important is accurate modeling of N32?

 

Colin: what sets the scale at which N3/2 peaks?

 

 

---

David Alonso

 

Notes:

• Projected tracers, e.g. LSST, tracers of matter fluctuations

• Focus on CMB lensing and WL, GC

• tSZ tomography: cross-correlate tSZ with clustering - constrain gas pressure / mass bias

• Cluster mass calibration - high-z clusters

• Tomography: reconstruct redshift dependence, Nx2pt

• Use tomography to constrain growth - break bias - growth degeneracy with CMB lensing

• Growth reconstruction: check probe consistency, consistency with LCDM

  • Two data sets: DECALS, KiDS / DES / Planck

  • Decouple growth from background - growth spline with nodes

  • S8(z): data comb gives evidence of lower growth at 0.2<z<0.6 -> driven by shear

  • Need CMB lensing for high-z

  • LCDM good fit with lower S8

• Systematics:

  • Photoz uncertainties: analytic marg, self-calib, CMB x less sensitive

  • Shear calibration:

  • Galaxy bias: hybrid EFT

 

Questions:

 

 

---

Alex Krolewski

 

Notes:

• Improve on CMB lensing auto with GC - growth of structure, brings in galaxy bias -> need all probes

• Related to S8 tension

• Use CMB lensing as xcheck of optical lensing

• Pick galaxy sample with high S/N

  • High z - overlap with lensing kernel

  • Angular coverage

  • WISE: infrared galaxy survey: all-sky, gals with old stellar pops can be easier to detect in WISE

• Three galaxy samples: blue, red, green z~0.6 - z~1.5

• Need to remove stars using GAIA - contamination left 1%

• Redshift distribution: no photoz - > do cross-correlation redshifts with specs, measure n(z) and bias evolution, so just include measured relations in theory

• Theory: linear + HO bias (dominated by linear modes), allows fix cosmo & HO bias

• Tests on mocks, calibration of scales used, lmax~250-300

• Redshift uncertainty: run sep. chains for all nz realizations -> full shape marg.

• Results: samples consistent, 2.6sigma tension with Planck in S8

 

Questions:

David A.: Can you say a bit more about the N(z) marginalization using clustering redshifts? E.g. do you need to worry about the fact that the measurements allow for negative values?

Blake: If I recall right, DES obtained the same S8-only constraint but did not report tension with Planck when considering the full posterior. Could you remind me how you obtained the 2.6sigma tension number and could a similar effect operate here?

 

 

---

Yan-Chuan Cai

 

Notes:

• ISW and CMB lensing around substructures

• ISW and CMB lensing: Sourced by same late-time grav potential 

• ISW: probe of accelerated expansion - time-varying potentials

• Photons in voids: cold-spot in CMB, photons in clusters: hot spot

• Usually: cross-correlations between primary CMB and LSS tracers (e.g. lensing)

  • Joint measurements of GC, CMB lensing, ISW

• Why superstructures?

  • Look at generalization of cluster cosmology, peak counts, etc.

  • Beyond 2pt

  • Beyond GR - different behaviour in high/low density regions

  • Granett et al., 2008: amplitude of stacked CMB temperature high compared to LCDM expectation

  • Question: what is the cause for this?

• Repeat analysis using DESI legacy survey 

  • reduce sample variance

  • No detection for temperature imprints from supervoids 

 

Questions:

Jia: why is there no lack of signal for void (but it is there for clusters..)? I.e.why “lensing is low” is not impacting void? Answer: could be related to photo-z bias, or something physical (e.g. neutrino free-streaming) but no definitive answer.

David A.: there was a recent paper measuring a negative ISW from voids at very high redshifts from QSOs. Do you have any thoughts on that? (this one)

Yan-Chuan Cai: Yes. I think the statistical significance isn’t very high,less than 3sigma I think, similar to many other analyses. It would be great to have more volume to beat down the variance.

 

---

Leander Thiele

 

Notes:

• NNs to map N-bodies to baryons: CNN / DeepSet

• Predict baryonic fields from DM only - baryons local, i.e. use local ML approach

• Usage:

  • Rapidly generate sims

  • Interpret trained model and learn about astro

• CNN:

  • DM -> pe, ne

  • Use CNN on 3D field, redshift zero

  • Semianalytic models

  • Main problem: sparsity, only small fraction of volume is interesting, overcome by biasing training sample using zoom-ins

  • Electron pressure spans large dynamic range (input trafos, semi-analytic model)

  • Small scales well fit, large scales better than models, projection improves performance

• DeepSet:

  • Concentrate on massive halos -> no transl symmetry

  • CNNs not best approach: spend lot of resource on empty regions, poor interpretability

  • Idea: can we use simulations representation to train NN? - DeepSet VAE

  • Restricted architecture improves on existing models

 

Questions:

• Interpolate between baryonic feedback models? Train on one sim and then do transfer learning on other sim

 

 

---

Jia Liu

 

Notes:

• Why sims? Test pipelines, systematics, astrophysics, covariance, modeling

• Why correlated? CMB foregrounds and LSS, not super useful for survey systematics because will be uncorrelated, but extragalactic, astrophysics syst will show up differently, input to train ML models

• Typical CMB sims: 2D, gravity only, CMB observables painted -> Sehgal, Stein

• Typical LSS sims: 2/3D, more cosmo, hydro/gravity only, curved/flat, smaller boxes

• Correlated sims need to accommodate both worlds

• current : run by experts in both areas

• Yuuki Omori: MultiDark Planck 2

• Roadmap:

  • Basis: gravity-only sims

  • Then send off to experts and paint on CMB / LSS observables

  • Coordination!

  • How to get gravity-only sims: fast full-sky lightcone (e.g. COLA, FastPM)

  • Challenges: computing, storage, requirements, maintenance, personnel

 

Questions:

 

 

---

Dongwon ‘DW’ Han

 

Notes:

• Need correlated sims: high-res, multi-frequency, need NG info

• Computationally expensive -> use DL

• mmDL: CMB kappa -> NG kappa, kSZ, tSZ, CIB, radio + lensed TUQ

• Network:

  • Data augmentation, not enough sims

  • Conversion / prediction

  • NG restoration step

• Results:

  • Reproduce source counts, power spectra, cross-correlations, bispectra, trispectra (CMB lensing biases)

  • Network can recover correlations between large and small scales even though trained on small patches

  • Variance in sims comparable to Knox

• Sims available publicly

• Allow mass-production of independent full-sky realizations

• Fast: forward-modeling

• Future:

  • Fixed cosmology - CAMELS?

  • Missing associated catalog - extension to create catalogs

  • Can we use network to learn optimal summary stats?

 

Questions:

 

08:00 Synergies of Large Scale Structure Surveys with CMB-S4: Plenary Summary Report

Speaker: Andrina Nicola (Princeton University)

CMB-S4-Aug2021-AN.pdf

08:35 → 09:10 Messengers from the Early Universe: Plenary Summary Report

Conveners: Joel Meyers (Southern Methodist University;) , Nathaniel Craig (UC Santa Barbara)

Notes

08:35 Messengers from the Early Universe: Plenary Summary Report

Speaker: Nathaniel Craig (UC Santa Barbara)

CMBS4_Messengers_Craig.pdf

09:10 → 09:45 The Time-Varying mm-Wave Sky: Plenary Summary Report

Conveners: Anna Ho (UC;LBL) , Gregg Hallinan (Caltech)

cmbs4-intro-plenary-final.pdf

cmbs4-recap.pdf

Notes

09:10 The Transient Radio Sky

20 min talk + 5 min Q&A

Speaker: Gregg Hallinan (Caltech)

Hallinan.pdf

09:35 The Time-Varying mm-Wave Sky: Recap

Speaker: Anna Ho (UC;LBL)

cmbs4-intro-plenary-final.pdf

09:45 → 10:05 Break

10:05 → 10:20 Backlighting the Baryons with CMB-S4: Plenary Introduction

Conveners: Alexie Leauthaud (UCSC) , Simone Ferraro (Lawrence Berkeley National Laboratory)

Notes

10:05 Backlighting the Baryons with CMB-S4: Plenary Introduction

Speaker: Simone Ferraro (Lawrence Berkeley National Laboratory)

CMB-S4-Aug_2021.pdf

10:20 → 10:35 Gravitational Waves: Plenary Introduction

Conveners: Raphael Flauger (UC San Diego) , Sarah Shandera (Pennsylvania State University;)

Notes

10:20 Gravitational Waves: Plenary Introduction

Speaker: Raphael Flauger (UC San Diego)

20210811.pdf

10:35 → 10:50 The Galactic ISM in 3D: Plenary Introduction

Conveners: Brandon Hensley (Princeton University) , Gina Panopoulou (Caltech)

Notes

10:35 The Galactic ISM in 3D: Plenary Introduction

Speaker: Brandon Hensley (Princeton University)

S4_3D_ISM.pdf

10:50 → 11:10 Break

11:10 → 14:00 Backlighting the Baryons with CMB-S4: Parallel

Conveners: Alexie Leauthaud (UCSC) , Simone Ferraro (Lawrence Berkeley National Laboratory)

Notes

11:10 Current measurements and future prospects: reconstructed velocities and halo thermodynamics

Speaker: Emmanuel Schaan (Lawrence Berkeley National Laboratory;)

schaan_s4_20210811.pdf

11:30 Current measurements and future prospects: pairwise kSZ

Speaker: Eve Vavagiakis (Cornell University)

CMB-S4 Summer 2021.pdf

11:50 Review: baryon effects in weak lensing

Speaker: Aurel Schneider (University of Zurich)

CMB-S42021.pdf

12:10 Discussion

12:25 Mid-Parallel Break

12:45 SZ calibration of baryon effects

Speaker: Colin Hill (Columbia)

JCH_SZ_Calibration.pdf

13:05 Projected fields kSZ

Speaker: Aleksandra Kusiak (Columbia University)

CMB-S4 kSZ projected-field.pdf

13:25 kSZ as a probe of ultralight axions

Speaker: Daniel Grin (Haverford College;)

s4_grin_farren.pdf

13:35 Discussion

11:10 → 14:00 Gravitational Waves: Parallel

Conveners: Raphael Flauger (UC San Diego) , Sarah Shandera (Pennsylvania State University;)

Notes

11:10 The quest for the SGWB with terrestrial detectors

Speaker: Tania Regimbau (LAPP/CNRS)

CMB_S4_regimbau.pdf

11:29 LISA and GW cosmology across 29 decades in frequency

Speaker: Robert Caldwell (Dartmouth College)

CMB-S4 summer meeting presentation.pdf

11:48 Beyond a measurement of the tensor-to-scalar ratio

Speaker: Daan Meerburg (University of Groningen;)

S4-August2021_PDM.pdf

12:07 Towards precision measurements of the primordial GW background spectrum: the role of CMB and direct GW detectors

Speaker: Paolo Campeti (Max-Planck-Institut für Astrophysik)

Campeti_CMBS4.pdf

12:25 Mid-Parallel Break

12:45 Measuring non-standard tensors with a BK-like experiment

Speaker: Prof. Clem Pryke (University of Minnesota)

Measure Non Standard Tensors with BK like experiment .pdf

13:03 Measuring the B-mode bispectrum from BICEP/Keck Array

Speaker: Toshiya Namikawa (University of Cambridge;)

Measuring B-mode bispectrum with BICEP_Keck Array.pdf

13:21 Discussion

11:10 → 14:00 The Galactic ISM in 3D: Parallel

Conveners: Brandon Hensley (Princeton University) , Gina Panopoulou (Caltech)

Notes

11:10 The ACT View of the Galactic Center

Speaker: Yilun Guan (University of Pittsburgh)

S4 Meeting ACT View of the Galactic Center.pdf

11:25 Multi-tracers analysis of the Faraday tomographic data

Speaker: Vibor Jelic (Ruder Boskovic Institute)

CMB-S4_Aug21_VJ.pdf

11:40 Reconstructing 3D magnetic fields associated with filamentary molecular clouds

Speaker: Mehrnoosh Tahani (National Research Council Canada)

MTahani_CMBS42021.pdf

11:55 Filaments, bubbles, super-bubbles, and other features of the magnetized solar neighborhood

Speaker: Juan Diego Soler (IAPS - Italian National Institute for Astrophysics)

Filaments, bubbles, super-bubbles, and other features of the magnetized solar neighborhood

12:10 Combining CMB Observations with Extinction Data to Create a 3D Dust Temperature Map

Speaker: Ioana Zelko (Harvard-CfA-UCLA)

presentation.pdf

12:25 Mid-Parallel Break

12:45 A new 3D model of Galactic microwave foreground dust emission based on filaments

Speaker: Carlos Hervias-Caimapo (Florida State University;)

DustFilaments_CMB-S4_summer_2021.pdf

13:00 Discussion

Speakers: Brandon Hensley (Princeton University) , Carlos Hervias-Caimapo (Florida State University;) , Gina Panopoulou (Caltech) , Ioana Zelko (Harvard-CfA-UCLA) , Juan Diego Soler (IAPS - Italian National Institute for Astrophysics) , Mehrnoosh Tahani (National Research Council Canada) , Vibor Jelic (Ruder Boskovic Institute) , Yilun Guan (University of Pittsburgh)

14:00 → 15:00 Gather.Town: Career/Networking

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

16:00 → 17:00 EPO Event - Teen Jeopardy

Are you READY! We are launching our first-ever CMB-S4 Jeopardy Night! Are you up for an evening of physics fun? Join us for an evening filled with science research challenges. What a great way to represent your high school and win fun prizes! CMB-S4 scientists will be joining you to share stories about their career paths and prepare you for VICTORY! Let the Games Begin!

Register at: https://forms.gle/sMv7pMaCGuYh3ccX7

Thursday, 12 August

07:00 → 08:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

08:00 → 08:35 Backlighting the Baryons with CMB-S4: Plenary Summary Report

Conveners: Alexie Leauthaud (UCSC) , Simone Ferraro (Lawrence Berkeley National Laboratory)

Notes

08:00 Backlighting the Baryons with CMB-S4: Plenary Summary Report

Speaker: Alexie Leauthaud (UCSC)

backlighting_baryons_CMBS4.pdf

08:35 → 09:10 Gravitational Waves: Plenary Summary Report

Conveners: Raphael Flauger (UC San Diego) , Sarah Shandera (Pennsylvania State University;)

Notes

08:35 Gravitational Waves: Plenary Summary Report

Speaker: Sarah Shandera (Pennsylvania State University;)

CMBS4SummaryReport2021.pdf

09:10 → 09:45 The Galactic ISM in 3D: Plenary Summary Report

Conveners: Brandon Hensley (Princeton University) , Gina Panopoulou (Caltech)

Notes

09:10 The Galactic ISM in 3D: Plenary Summary Report

Speaker: Gina Panopoulou (Caltech)

Galactic ISM in 3D: summary

The Galactic ISM in 3D Plenary summary.pdf

09:45 → 10:05 Break

10:05 → 10:20 From the Dark Ages to Reionization with CMB-S4: Plenary Introduction

Conveners: Marcelo Alvarez (Lawrence Berkeley National Laboratory) , Zhilei Xu (MIT)

Notes

10:05 From the Dark Ages to Reionization with CMB-S4: Plenary Introduction

Speaker: Marcelo Alvarez (Lawrence Berkeley National Laboratory)

From the Dark Ages to Reionization with CMB-S4 - Alvarez.pdf

10:20 → 10:35 Astrophysics and Cosmology with Galaxy Clusters: Plenary Introduction

Conveners: Heidi Wu (Boise State University) , Srinivasan Raghunathan (NCSA/UIUC)

Notes

10:20 Astrophysics and Cosmology with Galaxy Clusters: Plenary Introduction

Speaker: Srinivasan Raghunathan (NCSA)

S4_August2021_clusters_SRaghunathan

S4_August2021_clusters_SRaghunathan.pdf

10:35 → 10:50 Snowmass Planning and CMB-S4: Plenary Introduction

Conveners: Clarence Chang (Argonne National Laboratory;University of Chicago) , Scott Dodelson (Carnegie Mellon University)

CMB-S4_Snowmass_report .pptx

Notes

10:35 Snowmass Planning and CMB-S4: Plenary Introduction

Speaker: Clarence Chang (Argonne National Laboratory;University of Chicago)

CMB-S4_Snowmass.pdf

CMB-S4_Snowmass.pptx

10:50 → 11:10 Break

11:10 → 14:00 Astrophysics and Cosmology with Galaxy Clusters: Parallel

Conveners: Heidi Wu (Boise State University) , Srinivasan Raghunathan (NCSA/UIUC)

Notes

11:10 eRosita

Speaker: Vittorio Ghirardini (Max Planck Institute MPE)

presentazione.pdf

11:25 SPTxDES Cluster Cosmology

Speaker: Sebastian Bocquet (LMU Munich)

Bocquet.pdf

11:40 Understanding the mass and galaxy distribution in Clusters: A perspective from the edge of DM halos

Speaker: Susmita Adhikari (University of Chicago)

cmbs4_2021.pdf

11:55 Synergy between optical, SZ, and X-ray: Lessons learned from DES Cluster Cosmology

Speaker: Dr Tesla Jeltema (University of California, Santa Cruz)

cmb-s4_aug21.pdf

12:10 Discussion

12:25 Mid-Parallel Break

12:45 Cluster science using the synergy between CMB-S4 and Lynx

Speaker: Dr Grant Tremblay (Harvard University)

13:00 Gas in the outskirts of galaxy clusters

Speaker: Eric Baxter (University of Hawaii)

Baxter_GasOutskirts_CMBS4.pdf

13:15 Baryon pasting + high-z cluster virialization models

Speakers: Daisuke Nagai (Yale University;) , Dr Erwin Lau (Smithsonian Astrophysical Observatory) , Dr Han Aung (Yale University)

Modeling Multi-wavelength Surveys with Baryon Pasting

13:45 Discussion

11:10 → 14:00 From the Dark Ages to Reionization with CMB-S4: Parallel

Conveners: Marcelo Alvarez (Lawrence Berkeley National Laboratory) , Zhilei Xu (MIT)

Notes

11:10 Introduction to Reionization

The Epoch of Reionization (EoR) -- when ultraviolet photons emitted by the first stars and galaxies transformed the intergalactic medium from mostly neutral to mostly ionized -- is a primary science motivation of many current and upcoming facilities. The landscape of experiments is diverse, with some seeking a detection of the ionization field itself, and others instead going after the sources and sinks of ionizing photons. In this talk, I will briefly review the physics of reionization and the many ways in which it can in principle be constrained observationally. I will focus on the latest observational constraints and advances in theoretical modeling, and how the next generation of experiments can help fill key gaps in our current understanding of reionization, and ultimately, galaxy formation and cosmology.

Speaker: Jordan Mirocha (McGill University)

mirocha_cmbS4_2021.key

mirocha_cmbS4_2021.pdf

11:40 Physical modelling of patchy reionization

The epoch of cosmic reionization can be probed using the secondary anisotropies imprinted on the cosmic microwave background (CMB) temperature and polarization field. I will discuss the imprints of patchy reionization on the kSZ power spectrum and CMB B-mode polarization. I will introduce two new scaling relations to connect the kSZ and secondary B-mode power spectrum with the physics of reionization. I will discuss the advantage of a joint study of the kSZ signal and secondary B-mode polarization from CMB-S4 to get a better understanding of the epoch of reionization.

Speaker: Suvodip Mukherjee (Institut d'Astrophysique de Paris;University of Amsterdam)

Mukherjee_CMB_S4_2021.key

Mukherjee_CMB_S4_2021.pdf

11:55 The high-redshift tail of stellar reionization in LCDM is beyond the reach of the low-ell CMB

The first generation (Pop-III) stars can ionize 1-10% of the universe by z=15, when the metal-enriched (Pop-II) stars may contribute negligibly to the ionization. This low ionization tail might leave detectable imprints on the large-scale CMB E-mode polarization. However, we show that physical models for reionization are unlikely to be sufficiently extended to detect any parameter beyond the total optical depth through reionization. This result is driven in part by the total optical depth inferred by Planck 2018, indicating a reionization midpoint around z=8, which in combination with the requirement that reionization completes by z~5.5 limits the amplitude of an extended tail. To demonstrate this, we perform semi-analytic calculations of reionization including Pop-III star formation in minihalos with Lyman-Werner feedback. We find that standard Pop-III models need to produce very extended reionization at z>15 to be distinguishable at 2-sigma from Pop-II-only models, assuming a cosmic variance-limited measurement of the low-ell EE power spectrum. However, we show that unless appealing to extreme Pop-III scenarios, structure formation makes it quite challenging to produce high enough Thomson scattering optical depth from z>15, tau(z>15), and still be consistent with other observational constraints on reionization.

Speaker: Xiaohan Wu (Harvard CfA)

CMB-S4.pdf

12:10 Status of Reionization-Era Line Intensity Mapping

Recent years have seen an explosion in the number of line intensity mapping experiments, particularly those targeting the Epoch of Reionization. By targeting unresolved emission of a variety of spectral lines, these surveys will provide new windows into the nature of the high-redshift objects responsible for ionizing the interstellar medium. In this talk, I will briefly summarize the status of current and near-future experimental efforts, explore the scientific results they hope to obtain, and highlight important open questions as we move into the next generation of cosmological surveys.

Speaker: Patrick Breysse (New York University)

pcbreysse_CMBS4_2021.pdf

pcbreysse_CMBS4_2021.pptx

12:25 Mid-Parallel Break

12:45 Cross-correlating patchy kSZ with other probes of reionization

The kinematic Sunyaev-Zel’dovich (kSZ) effect contains a contribution from the inhomogeneous reionization process, and encodes valuable information about how reionization progressed. We examine several upcoming opportunities for cross-correlating the kSZ signal with other probes of Cosmic Dawn and the Epoch of Reionization. Specifically, we look at the 21cm signal, measured by radio interferometers such as HERA and the SKA, and wide-field high-redshift galaxy surveys, such as those from the Nancy Grace Roman Space Telescope. We show that in the sample variance-limited regime, a statistically significant cross-correlation signal is present. However, contamination from other signals, such as the primary CMB, may present observational difficulties. In particular, the foreground contamination for the 21cm signal presents a unique challenge that must be overcome to make a detection. We talk about potential methods for overcoming these difficulties, as well as prospects for future experiments.

Speaker: Paul La Plante (UC Berkeley)

cmb_s4_2021.key

13:00 Constraining reionization with the CMB optical depth fluctuation - Compton-y cross-correlation

In the era of the high-precision CMB measurements, in addition to the conventional power spectrum, other observables will help to constrain cosmology. For example, the gravitational lensing effect introduces correlations between different modes of CMB fluctuations. This mode-mode correlation has been used to reconstruct gravitational lensing from CMB data. Other secondary effects could also produce a similar mode-couplings in CMB. In this talk, I will introduce my recent works on constraining reionization through the optical depth fluctuations which cause another type of mode-mode correlation in CMB anisotropies. I will present the first measurement of the cross-correlation between optical-depth fluctuations --- Compton-y map for constraining reionization with Planck data.

Speaker: Toshiya Namikawa (University of Cambridge;)

2021-08-13_S4-tauxy.pdf

13:15 First Upper Limits from HERA on the 21 cm Power Spectrum

In this talk, I will present the first power spectrum upper limits from the Hydrogen Epoch of Reionization Array (HERA), a purpose-built 21 cm experiment under construction in South Africa. I will highlight several of the supporting efforts---especially calibration and systematics mitigation---that build confidence in our result and in our instrument more generally. Finally, I will discuss how this milestone for the HERA team fits into our broader quest to detect and characterize the 21 cm power spectrum from the Cosmic Dawn and how such a measurement will complement CMB-S4.

Speaker: Josh Dillon (UC Berkeley)

Dillon_CMB-S4_8-12-21.key

Dillon_CMB-S4_8-12-21.pdf

13:30 Discussion

11:10 → 14:00 Snowmass Planning and CMB-S4: Parallel

Conveners: Clarence Chang (Argonne National Laboratory;University of Chicago) , Scott Dodelson (Carnegie Mellon University)

CMB-S4_Snowmass_report .pptx

Notes

11:10 CF3. Dark Matter: Cosmic Probes

Speaker: Alex Drlica-Wagner (Fermilab/UChicago)

CF03-CMB-S4.pdf

11:25 CF4. Dark Energy and Cosmic Acceleration: The Modern Universe

Speaker: Anze Slosar (Brookhaven National Laboratory;)

presentation

11:40 CF5. Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before

Speaker: Deirdre Shoemaker (UT Austin)

CF5.pdf

11:55 CF6. Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities

Speaker: David Schlegel (Lawrence Berkeley National Lab)

CMBS4_Snowmass_CF6_12aug2021.pdf

12:10 CF7. Cosmic Probes of Fundamental Physics

Speaker: Ke Fang (University of Wisconsin-Madison)

CMB-S4_SnowmassCF7.pdf

12:25 Mid-Parallel Break

12:45 TF09: Astro-particle physics and cosmology

Speaker: Daniel Green (UC San Diego)

TF09 CMB-S4.pdf

13:00 Discussion

Speaker: Scott Dodelson (Carnegie Mellon University)

14:00 → 15:00 Gather.Town: How to get involved in EPO

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

Friday, 13 August

07:00 → 08:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

08:00 → 08:35 From the Dark Ages to Reionization with CMB-S4: Summary Report

Conveners: Marcelo Alvarez (Lawrence Berkeley National Laboratory) , Zhilei Xu (MIT)

Notes

08:00 From the Dark Ages to Reionization with CMB-S4: Summary Report

Speaker: Dr Zhilei Xu (MIT)

210813 Reionization session summary_Xu.pdf

08:35 → 09:10 Astrophysics and Cosmology with Galaxy Clusters: Summary Report

Conveners: Heidi Wu (Boise State University) , Srinivasan Raghunathan (NCSA/UIUC)

Notes

08:35 Astrophysics and Cosmology with Galaxy Clusters: Summary Report

Speaker: Heidi Wu (Boise State University)

cluster summary.pdf

09:10 → 09:45 Snowmass Planning and CMB-S4: Summary Report

Conveners: Clarence Chang (Argonne National Laboratory;University of Chicago) , Scott Dodelson (Carnegie Mellon University)

CMB-S4_Snowmass_report .pptx

Notes

09:10 Snowmass Planning and CMB-S4: Summary Report

Speaker: Scott Dodelson (Carnegie Mellon University)

CMB-S4_Snowmass_report .pdf

09:45 → 10:05 Break

10:05 → 10:50 Poster Session in Gather.Town

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4

10:50 → 11:10 Break

11:10 → 12:25 Junior Scientist Talks

Convener: Darcy Barron (University of New Mexico)

11:10 Likelihood-approximations for large-scale CMB data

Upcoming large angular scale CMB surveys aim at measuring the scalar-to-tensor ratio r, to determine the energy scale of inflation, and the optical depth to reionization tau. To measure these systematics and noise dominated signals, flexible likelihood approximation techniques are required. We present novel methods from likelihood approximations to likelihood-free inference techniques and improved systematics modelling for CMB surveys.

Speaker: Roger de Belsunce (University of Cambridge)

CMB-S4_tau_Belsunce.pdf

11:25 Simulating and Mitigating the Atmospheric Effects for CMB ground-based Observations

In this talk, I will present the simulation status of the atmospheric effects for the LSPE/Strip telescope. In particular, I will emphasize how this technique can be easily applied at the other CMB ground-based experiments like QUBIC that will observe the CMB from the Atacama sky

Speaker: Stefano Mandelli

Atmospheric_effects.pdf

11:40 Forecasting Constraints on Squeezed-limit Non-Gaussianity Through μ-T Correlations Using CMB-S4 and SKA

Acoustic dampening of the cosmic microwave background (CMB) power spectrum results from imperfect photon-baryon coupling in the pre-recombination plasma. At redshift 5 × 104 < z < 2 × 106 , the plasma has an effective chemical potential, and energy injections from acoustic dampening in this era create μ- type spectral distortions of the CMB. These μ-distortions trace the underlying photon density fluctuations, probing the primordial power spectrum from 50 Mpc−1 < k < 104 Mpc−1 . Small-scale power modulated by long-wavelength modes from squeezed-limit non-Gaussianities introduces cross-correlations between CMB temperature anisotropies and μ-distortions. Under single-field inflation models, μT correlations measured from an observer in an inertial frame should be exactly zero, thus any measured correlation rules out single- field inflation models. We are forecasting how well CMB-S4 + SKA1 & 2 can constrain primordial squeezed- limit non-Gaussianity—parameterized by fNL—using measurements of C μT ` . Using current specifications and foreground modeling, we expect σ(fNL) ∼ 5.

Speaker: David Zegeye (University of Chicago)

cmb-s4 presentation.pptx

11:55 Taurus: A Balloon-borne Polarimeter for Cosmic Reionization and Galactic Dust

Speaker: Steven Benton (Princeton University)

2021-08-13 Taurus (S4 Meeting).pdf

Link to google slides

12:10 B-mode constraint from SPIDER's first flight with SMICA: a spectral based component separation pipeline.

Speaker: Corwin Shiu (Princeton University;)

B mode constraints from SPIDER’s first flight with SMICA_ A spectral based component separation pipeline.pdf

12:25 → 12:40 Plenary

Collaboration Update (google slides)

Collaboration Update.pdf

Notes

12:25 Closeout

Speakers: John Carlstrom (University of Chicago;Argonne National Laboratory) , Julian Borrill (Lawrence Berkeley National Laboratory & UC Berkeley)

CloseOut.pdf

12:40 → 14:00 Gather.Town: Social

https://gather.town/app/j2Ozbwz01WxI9YKH/CMB-S4