Past Papers

Owned by Victor Buza (Unlicensed)
Last updated: Nov 08, 2024 by Prish Chakraborty
12 min read

  

  • Anmol Raina, "Disentangling the primordial nature of stochastic gravitational wave backgrounds with CMB spectral distortions", https://arxiv.org/abs/2309.02366, @ Zoom, at 5:00pm

  

  

  

  

  • Shu-Fan Chen, "The Atacama Cosmology Telescope: Multi-probe cosmology with unWISE galaxies and ACT DR6 CMB lensing", https://arxiv.org/abs/2409.02109 , @ Zoom, at 5:00pm

  

  • Aizhan Akhmetzhanova, "The Atacama Cosmology Telescope: Detection of Patchy Screening of the Cosmic Microwave Background", https://arxiv.org/abs/2401.13033 , @ Zoom, at 5:00pm

  

  

  • Prish Chakraborty, "The Atacama Cosmology Telescope: Cosmology from cross-correlations of unWISE galaxies and ACT DR6 CMB lensing", https://arxiv.org/abs/2309.05659, @ Zoom, at 5:00pm

 

 

  • Arthur Tsang, "Pixelated Reconstruction of Foreground Density and Background Surface Brightness in Gravitational Lensing Systems using Recurrent Inference Machines", https://arxiv.org/abs/2301.04168, @ Zoom, at 5:00pm

 

  • Prof. Zachary Slepian

Title:  Is Nature Its Own Mirror? Parity-Violation with Galaxy Quartets in BOSS

Abstract:  Recently we have shown that the galaxy 4-point correlation function, which measures an excess of quartets of galaxies over random, is sensitive to parity violation in our universe’s large-scale structure. It is fundamentally 3D and thus has a handedness even after averaging over orientations, in contrast to galaxy pair and triplet correlations. With this new observable, we have detected parity violation at high statistical significance using the largest currently available sample, the SDSS Baryon Oscillation Spectroscopic Survey’s roughly 1 M galaxies. If confirmed by upcoming sky surveys such as DESI this would indicate new physics operant in the Universe’s earliest moments. In this talk I will discuss this result and the many systematics tests performed to test its robustness, as well as prospects for the future, especially with DESI data.

 

 

 

  • Anmol Raina, "Consistently constraining fNL with the squeezed lensing bispectrum using consistency relations", https://arxiv.org/abs/2310.12959, @ Zoom, at 5:00pm

 

  • Wenzer Qin

Title: Probing exotic energy injection with the CMB and early star formation

Abstract: Dark matter interactions with Standard Model particles can inject energy at early times, altering the standard evolution of the early universe. In particular, this energy injection can perturb the spectrum of the cosmic microwave background (CMB) away from that of a perfect blackbody, alter the CMB anisotropy spectrum, and affect processes by which the first stars form. For this study, I will discuss recent work to upgrade the DarkHistory code package to more carefully track interactions among low energy electrons, hydrogen atoms, and radiation, in order to accurately compute the evolution of the CMB spectral distortion in the presence of Dark Matter energy injection. I will show results for the contribution to the spectral distortions from redshifts z < 3000 for arbitrary energy injection scenarios, new CMB anisotropy constraints on light dark matter, as well as the effect of exotic energy injection on early star formation.

 

  • Theo Simon

Title:  Constraining cosmological models with the effective field theory of large-scale structures

Abstract:  In this talk, I will present the paradigm of the effective field theory of large-scale structures (EFTofLSS) and how it can be used to constrain cosmological models. First, I will discuss the consistency of this theory and its predictive power, and then I will present the constraints of the EFTofLSS applied to BOSS and eBOSS data on the LCDM model. Finally, I will mention the constraints from this theory on early dark energy, a model that potentially resolves the Hubble tension, and on decaying cold dark matter,  a model that possibly resolves the S8 tension.

  • Prof. Cumrun Vafa, @ Zoom, at 5:00pm

Title:  Quantum Gravity and A Unification of the Dark Sector

Abstract:  In this talk I apply consistency conditions of quantum gravity to the dark sector.   Motivated by the smallness of the dark energy combined with other experimental data, one is naturally led to a corner of the quantum gravity landscape with one extra mesoscopic dimension in the micron range. Interestingly this also leads to graviton excitations in the 5th dimension as an unavoidable candidate for the dark matter.  Moreover TCC conjecture applied to the late time cosmology motivates specific initial conditions in this scenario, leading to the right abundance of dark matter gravitons and an explanation of the cosmological coincidence problem.  We show how this novel dark matter scenario may also resolve the S8 tension.

 

  • Aizhan Akhmetzhanova, "Cosmology with 6 parameters in the Stage-IV era: efficient marginalisation over nuisance parameters”, https://arxiv.org/abs/2301.11895, @ Zoom, at 5:00pm

  • Gemma Zhang, “Beyond Gaussian Noise: A Generalized Approach to Likelihood Analysis with non-Gaussian Noise”, https://arxiv.org/abs/2302.03046, @ Zoom, at 5:00pm

  • Georgios Valogiannis, “Constraints on S8 from a full-scale and full-shape analysis of redshift-space clustering and galaxy-galaxy lensing in BOSS”, https://arxiv.org/abs/2301.08692 , @ Zoom, at 5:00pm

  • Gabriela Sato-Polito (External Speaker from Johns Hopkins), "Cosmology and astrophysics with the extragalactic light: background and fluctuations", @ Zoom, at 4:00pm & Lyman 330

Abstract:

 The aggregate light emitted by all extragalactic sources can be measured either as an absolute intensity or through its spatial fluctuations; these are known as line-intensity mapping (LIM) when a particular line transition is targeted. I will discuss how these measurements can be used both to investigate the presence of speculative sources of radiation, such as decaying dark matter, and learn about galaxy evolution. I then focus on intensity mapping and discuss how the unique characteristics of these measurements (e.g. wide redshift coverage, sensitivity to faint sources, and mapping speed) may enable a variety of scientific goals, some of the challenges in realizing them and promising future directions.


  • Benjamin Schmitt, Overview of the CMB-S4 experiment, @ Zoom, at 5:00pm

  • Miranda Eiben, “Evidence for Line-of-Sight Frequency Decorrelation of Polarized Dust Emission in Planck Data" https://arxiv.org/abs/2101.09291, @ Zoom, at 5:00pm

  • Sebastian Wagner-Carena (External Speaker from Stanford), "From Images to Dark Matter: End-to-End Inference of Substructure from Hundreds of Strong Gravitational Lenses", @ Zoom, at 5:00pm

Abstract:

Constraining the distribution of small-scale structure in our universe allows us to probe alternatives to the cold dark matter paradigm. Strong gravitational lensing offers a unique window into small dark matter halos because these halos impart a gravitational lensing signal even if they do not host luminous galaxies. We create large datasets of strong lensing images with realistic low-mass halos, Hubble Space Telescope (HST) observational effects, and galaxy light from HST's COSMOS field. Using a simulation-based inference pipeline, we train a neural posterior estimator of the subhalo mass function (SHMF) and place constraints on populations of lenses generated using a separate set of galaxy sources. We find that by combining our network with a hierarchical inference framework, we can both reliably infer the SHMF across a variety of configurations and scale efficiently to populations with hundreds of lenses. By conducting precise inference on large and complex simulated datasets, our method lays a foundation for extracting dark matter constraints from the next generation of wide-field optical imaging surveys.


SPRING BREAK


 

  • Mila Chadayammuri (CfA), "The Importance of Being Interpretable: Toward An Understandable Machine Learning Encoder for Galaxy Cluster Cosmology", @ Zoom, at 5:00pm

  • Georges Obied, "A Tale of Two U(1)'s: Kinetic Mixing from Lattice WGC States", @ Zoom, at 5:00pm  

 

  • Çağan Şengül, "Galaxy cluster strong lensing cosmography: cosmological constraints from a sample of regular galaxy cluster" ,   https://arxiv.org/abs/2110.06232 @ Zoom, at 5:00pm

 


 

Abstract:
 

Patterns and complex textures are ubiquitous in astronomical data but challenging to quantify. I will present a new powerful statistic called the “scattering transform”. It borrows ideas from convolutional neural nets (CNNs) while retaining the advantages of traditional statistics. As an example, I will show its application to weak lensing cosmology, where it outperforms classic statistics and is on a par with CNNs. I will also show interesting visual interpretations of the scattering transform and its advantages for practical data analysis. I argue that the scattering transform provides a powerful new approach in cosmology and beyond.


 

  • Stephen Chen (External Speaker from Berkeley) presented his latest research:

Abstract:
 
Spectroscopic surveys are a powerful cosmological probe, encoding information about structure formation and the geometry of the universe in the 3D distribution of galaxies. Upcoming surveys like DESI, which will increase the number of measured galaxy redshifts by an order of magnitude, will test our ability to use this information while providing opportunities to test fundamental physics in unprecedented ways. In this talk I will discuss our recent work on a new method to combine the two main prongs of these surveys--redshift-space distortions and BAO--within the framework of Lagrangian perturbation theory. As an illustrative example, I will discuss the application of this method to data from the BOSS survey, obtaining cosmological constraints that are competitive but consistent with primary CMB and lensing measurements. I will also discuss future prospects for perturbation theory analyses of large-scale structure, for example by jointly analyzing spectroscopic and lensing surveys.

 

  • Ted Macioce (External Speaker from Caltech) presented his latest research on the kSZ effect:

Abstract:
 
Measuring the kinetic Sunyaev-Zel’dovich (kSZ) effect is a promising technique to constrain both cosmic growth and galaxy cluster formation. Detecting the kSZ effect in massive galaxy clusters will become increasingly feasible as millimeter-wave telescopes gain sensitivity and resolving power over multiple frequency bands. While such kSZ measurements will have unprecedented sensitivity, they will also be contaminated by emission from dusty star-forming galaxies, primary anisotropies of the cosmic microwave background (CMB), and the typically dominant thermal SZ signal, making analysis efforts difficult. Current kSZ forecasts account for these contaminants in a simplified way, relying on assumptions that may not apply in the high-resolution regime. Moreover, they typically use Fisher matrix analyses, which cannot give a fully accurate description of the degeneracies among the physical parameters describing the cluster. We present a new mock observation and analysis pipeline for kSZ images that uses more detailed noise models and more sophisticated analysis methods to extract peculiar velocities, temperatures, and optical depths more accurately. With these mock observations, we will inform the designs of next-generation millimeter telescopes targeting kSZ observations by identifying the optimal instrumentation choices for both cosmological and cluster-scale constraints. The software pipeline we develop will also be directly usable as an analysis tool once observations from such telescopes become available.


 

 

 

 

  • Nakai, Suzuki, Takahashi, Yamada, Gravitational Waves and Dark Radiation from Dark Phase Transition: Connecting NANOGrav Pulsar Timing Data and Hubble Tension, arxiv.org/2009.09754 (presented by Nick DePorzio) @ Zoom, at 5:00

 

  • SPIDER Collaboration, A Constraint on Primordial B-Modes from the First Flight of the SPIDER Balloon-Borne Telescope, arxiv.org/2103.13334 (presented by Jeffrey Filippini) @ Zoom, at 5:00

 

  • Chen, Lee, Dvorkin, Precise and Accurate Cosmology with CMBxLSS Power Spectra and Bispectra, arxiv.org/2103.01229 (presented by Shu-Fan Chen) @ Zoom, at 5:00

 

  • Denzel, Mukherjee, Saha, A new strategy for matching observed and simulated lensing galaxies, arxiv.org/2102.10114 (presented by Arthur Tsang) @ Zoom, at 5:00

 

  • Liu, Valogiannis, Battaglia, Bean, Constraints on f(R) and nDGP Modified Gravity Model Parameters with Cluster Abundances and Galaxy Clustering, arxiv.org/2101.08728 (presented by Georgios Valogiannis) @ Zoom, at 5:00

 

  • Minami, Komatsu, New Extraction of the Cosmic Birefringence from the Planck 2018 Polarisation Data, arxiv.org/2011.11254 (presented by Clara Vergès) @ Zoom, at 5:00

 

  • Jamieson, Loverde, Position-dependent Voronoi probability distribution functions for matter and halos, arxiv.org/2012.10508 (presented by Çağan Şengül) @ Zoom, at 5:00

 

  • Kannawadi, Rosenberg, Hoekstra, Mitigating the effects of undersampling in weak lensing shear estimation with metacalibration, arxiv.org/2010.04164 (presented by Arthur Tsang) @ Zoom, at 5:00

 

  • Lizancos, Challinor, Carron, Impact of internal-delensing biases on searches for primordial B-modes of CMB polarisation, arxiv.org/2007.01622 (presented by Anton Lizancos) @ Zoom, at 5:00

 

  • Boruah et al., Peculiar velocities in the local Universe: comparison of different models and the implications for Ho and dark matter, arxiv.org/2010.01119 (presented by Sasha Brownsberger) @ Zoom, at 5:00

 

  • Zelko, Finkbeiner, Implications of Grain Size Distribution and Composition for the Correlation Between Dust Extinction and Emissivity, arxiv.org/2009.11869 (presented by Ioana Zelko) @ Zoom, at 5:00

 

  • Meneghetti et al., An excess of small-scale gravitational lenses observed in galaxy clusters, arxiv.org/2009.04471 (presented by Ana Diaz Rivero) @ Zoom, at 5:00

 

  • Buch et al., Dark Matter Substructure under the Electron Scattering Lamppost, arxiv.org/2007.13750 (presented by Linda Xu) @ Zoom, at 4:00

 

  • Cheng et al., Allys et al., A new approach to observational cosmology using the scattering transform, arxiv.org/2006.08561 and arxiv.org/2006.06298 (presented by Maya Burhanpurkar) @ Zoom, at 4:00

 

  • Domenech, Chen, Kamionkowski, Loeb, Lensing anomaly as a fingerprint of alternative scenarios to inflation, arXiv:2005.08998 (presented by Arthur Tsang) @ Zoom, at 4:00

 

  • Jedamzik, Pogosian, Relieving the Hubble Tension with Primordial Magnetic Fields, arXiv:2004.09487 (presented by Georges Obied) @ Zoom, at 5:30

 

  • Wu, Motloch, Raveri, Hubble constant tension between CMB lensing and BAO measurements, arXiv:2004.10207 (presented by Arthur Tsang) @ Zoom, at 5:30

 

  • Barreira, Cabass, Lozanov, Schmidt, Compensated Isocurvature Perturbations in the Galaxy Power Spectrum, arXiv:2002.12931 (presented by Shu-Fan Chen) @ Zoom, at 5:30

 

  • He, Ma, Zheng, Resolving Hubble Tension by Self-Interacting Neutrinos with Dirac Seesaw, arXiv:2003.12057 (presented by Nick DePorzio) @ Zoom, at 5:30

 

  • Pandey, Raveri, Jain, A model independent comparison of supernova and strong lensing cosmography: implications for the Hubble constant tension, arXiv:1912.04325 (presented by Ana Diaz) @ Zoom, at 5:30

 

  • List, Lewis, A unified framework for 21cm tomography sample generation and parameter inference with Progressively Growing GANs, arXiV:2002.07940 (presented by Julian Munoz) @ Lyman 330, at 5:30

 

  • Dai et al., Asymmetric Surface Brightness Structure of Lensed Arc in SDSS J1226+2152: A Case for Dark Matter Substructure, arXiV:2001.00261 (presented by Çağan Şengül) @ M-340, at 5:45

 

  • Ivanov, Simonovic, Zaldarriaga, Cosmological Parameters and Neutrino Masses from the Final Planck and Full-Shape BOSS Data, arXiv:1912.08208 (presented by Hayden Lee) @ Lyman 330, at 5:30

 

  • Baushev, Pilipenko, The central cusps in dark matter halos: fact or fiction? arXiV:1808.03088 (presented by Çağan Şengül) @ M-340, at 5:45

 

  • Lin, Mack, Hou, Investigating the Hubble Constant Tension -- Two Numbers in the Standard Cosmological Model arXiV:1910.02978 (presented by Sasha Brownsberger) @ Lyman 330, at 5:30

  • Capparelli, Caldwell, Melchiorri, Cosmic Birefringence Test of the Hubble Tension, arXiV:1909.04621 (presented by Linda Xu) @ M-340, at 5:45

  • Brehmer, Mishra-Sharma, Hermans, Louppe, Cranmeri, Mining for Dark Matter Substructure: Inferring subhalo population properties from strong lenses with machine learning, arXiV:1909.02005 (presented by Arthur Tsang) @ Lyman 330

  • Jeong, Kamionkowski, Gravitational waves, CMB polarization, and the Hubble tension, arXiV:1908.06100 (presented by Benjamin Racine) @ 160 concord avenue, room M-340

  • Keck Array and BICEP2 Collaborations, BICEP2 / Keck Array XI: Beam Characterization and Temperature-to-Polarization Leakage in the BK15 Dataset, arXiV:1904.01640 (presented by Tyler St Germaine)

  • Alexander, Bramburger, Mc Donough, Dark Disk Substructure and Superfluid Dark Matter, arXiV:1901.03694 (presented by Evan McDonough)

  • Linde, On the problem of initial conditions for inflation, arXiV:1710.04278 (presented by Çağan Şengül, moved from April 30)

  • Li, Frenk, Cole, Wang, Gao, Projection effects in the strong lensing study of subhaloes, arXiV:1612.06227 (presented by Arthur Tsang)

  • Riess, Casertano, Yuan, Macri, Scolnic, Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM, arXiV:1903.07603 (presented by Linda Xu)

  • Special Monday Journal Club / Seminar: Philcox, Sherwin, van Engelen, Detection and Removal of CMB B-mode Dust Foregrounds with Signatures of Statistical Anisotropy, arXiV:1805.09177 (presented by Oliver Philcox in M-340 at 160 Concord Ave)

  • Yuan, Eisenstein, Decorrelating the errors of the galaxy correlation function with compact transformation matrices, arXiV:1901.05019 (presented by Sihan Yuan)

  • Coulton, Spergel : The bispectrum of polarized galactic foregrounds, arXiV:1901.04515 (presented by Ben Racine)

  • Ribli, Pataki, Matilla, Hsu, Haiman, Csabai: Weak lensing cosmology with convolutional neural networks on noisy data, arXiV: 1902.03663 (presented by Ana Diaz Rivero)

  • Madhavacheril, Battaglia, Smith, Sievers : Cosmology with kSZ: breaking the optical depth degeneracy with Fast Radio Bursts, arXiV:1901.02418  (presented by Nicholas DePorzio)

  • Raveri, Hu, Sethi : Swampland Conjectures and Late-Time Cosmology, arXiV:1812.10448  (presented by Georges Obied)

  • Poulin, Smith, Karwal, Kamionkowski: Early Dark Energy Can Resolve The Hubble Tension, arXiV:1811.04083  (presented by Linda Xu)

  • Hadzhiyska, Spergel, Dunkley: A Small-Scale Modification to the Lensing Kernel, arXiV:1711.03168
    Hadzhiyska, Spergel: Measuring the Duration of Last Scattering, arXiV:1808.04083 
    (presented by Boryana Hadzhiyska)

  • Shanks, Hogarth, Metcalfe: GAIA Cepheid parallaxes and ‘Local Hole’ relieve H0 tension, arXiV:1810.02595
    Riess, Casertano, Kenworthy, Scolnic, Macri: Seven Problems with the Claims Related to the Hubble Tension in arXiv:1810.02595, arXiV:1810.03526 
    Shanks, Hogarth, Metcalfe: H0 Tension: Response to Riess et al arXiv:1810.03526, arXiV:1810.07628
    (presented by Ana Diaz Rivero)

  • Satoru Takakura et al, Measurements of tropospheric ice clouds with a ground-based CMB polarization experiment, POLARBEAR, arXiV:1809.06556 (presented by James Cornelison)

  • Bender, SPT collaboration, Year two instrument status of the SPT-3G cosmic microwave background receiver, arXiV:1809.00036 (presented by James Cornelison)

  • L. E. Ibanez, V. Martin-Lozano, I. Valenzuela, Constraining Neutrino Masses, the Cosmological Constant and BSM Physics from the Weak Gravity Conjecture,  arXiV:1706.05392 (presented by Georges Obied) 

  • Anna Ijjas & Paul J. Steinhardt, Bouncing Cosmology made simple, arXiV:1803.01961 (presented by Victor Buza) 

  • Hongwan Liu: special Journal Club "seminar" about the recent Edges result: Too Hot, Too Cold or Just Right? Implications of a 21-cm Signal for Dark Matter Annihilation and Decay, arXiV:1803.09739 

  • Duncan J. Watts et al, A Projected Estimate of the Reionization Optical Depth Using the CLASS Experiment’s Sample-Variance Limited E-Mode Measurement, arXiV:1801.01481  (presented by Lingzhen Zeng) 

  • E. Castorina et al, Primordial non-Gaussianities and zero bias tracers of the Large Scale Structure, arXiV:1803.11539  (presented by Linda Xu)

  • M. Pospelov et al, New Physics in the Rayleigh-Jeans Tail of the CMB, arXiV:1803.07048 (presented by Julian Muñoz)

  • S. Vagnozzi et al, Constraints on the sum of the neutrino masses in dynamical dark energy models with w(z)≥−1 are tighter than those obtained in ΛCDM, arXiv:1801.08553 (presented by Ana Diaz Rivero)

  • N. Krachmalnicoff et al, The S-PASS view of polarized Galactic Synchrotron at 2.3 GHz as a contaminant to CMB observations, arXiv:1802.01145 (presented by Benjamin Racine)

  • Dizgah, Lee, Muñoz, Dvorkin, Galaxy Bispectrum from Massive Spinning Particles, arXiv:1801.07265 (presented by Azadeh Moradinezhad Dizgah)

  • TBD (presented by Tyler St. Germaine)

  • Abitbol, Hill, and Johnson, Foreground-Induced Biases in CMB Polarimeter Self-Calibration, arXiv:1512.06834 (presented by James Cornelison)

  • G. E. Addison , Y. Huang , D. J. Watts et al, Quantifying discordance in the 2015 Planck CMB spectrum, arXiv:1511.00055 (presented by Georges Obied)

  • J. Carron, A. Lewis, A. Challinor, Internal delensing of Planck CMB temperature and polarization, arXiv:1701.01712 (presented by Victor Buza)

  • A. Manzotti, K. T. Story, W. L. K. Wu et al, CMB Polarization B-mode Delensing with SPTpol and Herschel, arXiv:1701.04396 (presented by Kirit Karkare)

  • Nierenberg et al, Probing dark matter substructure in the gravitational lens HE0435-1223 with the WFC3 grism, arXiv:1701.05188 (presented by Ana Diaz Rivero)

  • Castorina et al, DEMNUni: The clustering of large-scale structures in the presence of massive neutrinos, arXiv:1505.07148 (presented by Nina Maksimova)

  • M. Lewandowski, A. Maleknejad, L. Senatore, An effective description of dark matter and dark energy in the mildly non-linear regime, arXiv:1611.07966 (presented by Sruthi Narayanan)

  • Zheng et al, An Improved Model of Diffuse Galactic Radio Emission from 10 MHz to 5 THz, arXiv:1605.04920 (presented by Ioana Zelko)

  • A. Kogut, D.J. Fixsen, Foreground Bias From Parametric Models of Far-IR Dust Emission, arXiv:1607.02150 (presented by Tansu Daylan)

  • P. D. Meerburg, M. Munchmeyer, J. B. Munoz, X. Chen, Prospects for Cosmological Collider Physics, arXiv:1610.06559 (presented by Xingang Chen)

  • T. Louis et al, The Atacama Cosmology Telescope: two-season ACTPol spectra and parameters, arXiv:1610.02360 (presented by Victor Buza)

  • C. Heinrich, V. Miranda, W. Hu, Complete Reionization Constraints from Planck 2015 Polarization, arXiv:1609.04788 (presented by Georges Obied)

  • R. Caldwell, C. Hirata, M. Kamionkowski, Dust polarization and ISM turbulence, arXiv:1608.08138 (presented by Azadeh Moradinejad)

Copyright © 2024 The President and Fellows of Harvard College * Accessibility * Support * Request Access * Terms of Use