New Time!
CCAPP Cosmology Lunch meets on Thursdays at 1:00 pm in the Price Place (PRB M2005).
The smallscale structure problems of the universe can be solved by
selfinteracting dark matter that becomes strongly interacting at low energy. A particularly
predictive model for the selfinteractions is resonant shortrange interactions
with an Swave scattering length that is much larger than the range. The velocity
dependence of the cross section in such a model provides an excellent fit to selfinteraction
cross sections inferred from darkmatter halos of galaxies and clusters of
galaxies if the darkmatter mass is about 19 GeV and the scattering length is about
17 fm. Such a model makes definite predictions for the fewbody physics of weakly
bound clusters of the darkmatter particles. The formation of the twobody bound
cluster is a bottleneck for the formation of larger bound clusters. We calculate the
production of twobody bound clusters by threebody recombination in the early universe
under the assumption that the dark matter particles are identical bosons, which
is the most favorable case. If the darkmatter mass is 19 GeV and the scattering
length is 17 fm, the fraction of dark matter in the form of twobody bound clusters
can increase by as much as 4 orders of magnitude when the darkmatter temperature
falls below the binding energy, but its present value remains less than 10−6
. The
present fraction can be increased to as large as 10−3 by relaxing the constraints from
smallscale structure and decreasing the mass of the dark matter particle.
June 28, 2018
 Visitor talk: Alice Pisani, Title: Constraining Cosmology with Cosmic Voids
Abstract:
Cosmic voids, the emptiest regions in the Universe, are an increasingly
active sector of galaxy clustering analysis. In this talk I will explain
why voids are interesting tools for cosmology and what kind of
voidrelated observables we can focus on. I will discuss the treatment
of systematics and present some recent methods and results. Finally I
will discuss what we can expect from current and upcoming surveys in
term of constraining power.
Abstract:
In this talk I will give an overview of the Physics of the Accelerating Universe Survey (PAUS): a unique combination of a large fieldofview and 40 narrowband (NB) filters (12.5nm FWHM) that span the wavelength range from 450nm to 850nm and that was commissioned successfully in June 2015 on the WHT. This exquisite wavelength sampling results in photometric redshifts with a precision that approaches that of spectroscopic measurements, while being able to cover large areas of sky. I will present the current photometric redshift performance comparing to the zCOSMOS spectroscopic sample and the new photoz templatebased code that we have developed to estimate photometric redshifts for a narrow band photometric survey.
April 19, 2018  Xiao might talk about constraints on sublunar mass range for primordial black holes if time permits it.
 Visitor talk, Sten Delos: Constraining the primordial power spectrum using minihalos
Abstract: Ultracompact minihalos (UCMHs) have attracted considerable interest as a probe of the primordial power spectrum at small scales. However, previous treatments assumed that halos collapsing at early times possess an extremely steep r^9/4 density profile. We recently found that UCMHs actually develop shallower r^3/2 or r^1 inner profiles depending on the shape of the power spectrum, but these halos are still highly concentrated due to their early formation. I will discuss these results and the factors that set the inner density profile of a dark matter halo. I will also outline the process of deriving power spectrum constraints in this revised picture. Since the formalism can now include halos that collapse at any time, our preliminary revised constraints turn out to be stronger than prior constraints from UCMHs. April 5, 2018  Visitor talk, Lucas Seco: Probing Dark Matter SelfInteractions with Disk Galaxies
Abstract: Selfinteracting Dark
Matter (SIDM) has been proposed as a way to help reconcile small scale
astrophysical observations with CDM predictions. We use Nbody
simulations to study the effect of SIDM on the morphology of disk
galaxies falling into galaxy clusters. An effective drag force arises
from dark matter scatterings and leads to offsets of the stellar disk
with respect to its surrounding halo, causing distortions in the disk.
We show that potentially observable warps, asymmetries, and thickening
of the disk occur in simulations with currently allowed crosssections.
With further analysis of the potential systematic uncertainties of these
novel probes, we believe it could be possible to constrain SIDM
crosssections with current and future observations.
March 29, 2018 March 22, 2018 March 15, 2018 Abstract: A robust measurement of galaxy clustering relies on our understanding of imaging systematics such as Galactic Extinction, and how they introduce fluctuations in galaxy density. In this talk we will present the idea of using Artificial Neural Networks in modeling the dependence of galaxy density on imaging systematics. This method could be used for systematic mitigation and therefore is beneficial to ongoing and future galaxy surveys such as eBOSS and DESI.
February 15, 2018  Daniel Martens on using BOSS data to analyze intrinsic alignment effects on redshift space distortion parameters.
February 8, 2018
October 25, 2017  Denise Schmitz, Seminar: "Time Evolution of Galaxy Intrinsic Alignments"
October 4, 2017
Sep 27, 2017
Sep 20, 2017
Jul 19, 2017
 Feeney et al., Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder
 Miranda et al., Finding structure in the dark: coupled dark energy, weak lensing, and the mildly nonlinear regime
 Amon et al., KiDSi800: Comparing weak gravitational lensing measurements in samesky surveys
 Louis et al., Measuring Polarized Emission in Clusters in the CMB S4 Era
 Penrose, Correlated "noise" in LIGO gravitational wave signals: an implication of Conformal Cyclic Cosmology
 Smith et al., What if the gravitational waves detected in 2015 were strongly lensed by massive galaxy clusters?
 Harada et al., Spins of primordial black holes formed in the matterdominated phase of the Universe
 Koo & Lee, Detection of the Intrinsic Spin Alignments in Isolated Spiral Pairs: Another Local Anomaly?
 Hirata et al., Detecting primordial gravitational waves with circular polarization of the redshifted 21 cm line: I. Formalism
 Mishra & Hirata, Detecting primordial gravitational waves with circular polarization of the redshifted 21 cm line: II. Forecasts
 Rubin et al., The Discovery of a Gravitationally Lensed Supernova Ia at Redshift 2.22
 Ravenni et al., Primordial nonGaussianity with μtype and ytype spectral distortions: exploiting Cosmic Microwave Background polarization and dealing with secondary sources
Jul 05, 2017
 Aylor et al., https://arxiv.org/abs/1706.10286, "A Comparison of Cosmological Parameters Determined from CMB Temperature Power Spectra from the South Pole Telescope and the Planck Satellite"
 Yao et al., https://arxiv.org/abs/1707.01072, "Effects of SelfCalibration of Intrinsic Alignment on Cosmological Parameter Constraints from Future Cosmic Shear Surveys"
 Efstathiou & Lemos, https://arxiv.org/abs/1707.00483, "Problems with KiDS"
 Venumadhav et al., https://arxiv.org/abs/1707.00003, "Gravitational Microlensing During Caustic Crossings"
 Krause et al., https://arxiv.org/abs/1706.09359, "Dark Energy Survey Year 1 Results: MultiProbe Methodology and Simulated Likelihood Analyses"
Jun 7, 2017
 Deutsch et al., https://arxiv.org/abs/1705.08907, "Polarized Sunyaev Zel'dovich tomography"
 Minoda et al., https://arxiv.org/abs/1705.10054, "Thermal SunyaevZel'dovich effect in the intergalactic medium with primordial magnetic fields"
 Gall et al., https://arxiv.org/abs/1705.10806v1, "An updated Type II supernova Hubble diagram"
 Kuhnel et al., https://arxiv.org/abs/1705.10361, "Primordial BlackHole and Macroscopic DarkMatter Constraints with LISA"
 Green, https://arxiv.org/abs/1705.10818, "Astrophysical uncertainties on stellar microlensing constraints on multiSolar mass primordial black hole dark matter"
 Shin et al., https://arxiv.org/abs/1705.11167, "The ellipticity of galaxy cluster halos from satellite galaxies and weak lensing"
May 31, 2017
 White and Padmanabhan, 2017, https://arxiv.org/abs/1705.09669, "Matched filtering with interferometric 21cm experiments"
 Emami and Smoot, 2017, https://arxiv.org/abs/1705.09924, "Observational Constraints on the Primordial Curvature Power Spectrum"
 Kovetz, https://arxiv.org/abs/1705.09182, "Probing PrimordialBlackHole Dark Matter with Gravitational Waves"
 Deutsch et al., https://arxiv.org/abs/1705.08907, "Polarized Sunyaev Zel'dovich tomography"
 Uhlemann et al., https://arxiv.org/abs/1705.08901, "A question of separation: disentangling tracer bias and gravitational nonlinearity with countsincells statistics"
May, 17 2017
 Laurent et al., 2017, https://arxiv.org/abs/1705.04718, "Clustering of quasars in SDSSIV eBOSS: study of potential systematics and bias determination"
 Ross et al., 2017, https://arxiv.org/abs/1705.05442, "Optimized Clustering Estimators for BAO Measurements Accounting for Significant Redshift Uncertainty"
 Herbel et al., 2017, https://arxiv.org/abs/1705.05386, "The redshift distribution of cosmological samples: a forward modeling approach"
 Aghamousa et al., 2017, https://arxiv.org/abs/1705.05234, "A nonparametric consistency test of the ΛCDM model with Planck CMB data"
 Assassi et al., 2017, https://arxiv.org/abs/1705.05022, "Efficient Evaluation of Cosmological Angular Statistics"
May, 11 2017
 Scottez et al., 2017, https://arxiv.org/abs/1705.02629, "Testing the accuracy of clustering redshift with simulations"
 Masters et al., 2017, https://arxiv.org/abs/1704.06665, "The Complete Calibration of the ColorRedshift Relation (C3R2) Survey: Survey Overview and Data Release 1"
 Keck Array 2017, https://arxiv.org/abs/1705.02523, "BICEP2 / Keck Array IX: New Bounds on Anisotropies of CMB Polarization Rotation and Implications for AxionLike Particles and Primordial Magnetic Fields"
April, 19 2017
 Mackenzie et al., 2017, https://arxiv.org/abs/1704.03814, "Evidence against a supervoid causing the CMB Cold Spot"
 Davis and Fairbairn, 2017, https://arxiv.org/abs/1704.05073, "A "nu" look at gravitational waves: The black hole birth rate from neutrinos combined with the merger rate from LIGO"
 Merten et al., 2017, https://arxiv.org/abs/1704.05072, "Characterising dark matter haloes with computer vision"
 Heavens et al., 2017, https://arxiv.org/abs/1704.03467, "No evidence for extensions to the standard cosmological model"
 Liao et al., 2017, https://arxiv.org/abs/1704.04329, "Test of the FLRW metric and curvature with strong lens time delays"
 LIGO collaboration, 2017, https://arxiv.org/abs/1704.04628, "Search for intermediate mass black hole binaries in the first observing run of Advance LIGO"
March, 29 2017
 Speaker: Alex Mead
 "Is the sphericalcollapse model of halo formation useful?"

Abstract: I will discuss differences in nonlinear structure formation between cosmological models that are designed so as to share a lineartheory power spectrum at redshift zero, but that differ in their growth histories. Simulations of these cosmologies are seen to share a largescale structure skeleton, but differ in the details of their halo populations. I will demonstrate that these differences can be largely understood via the cosmology dependence of sphericalcollapsemodel predictions for the formation times and average densities of the haloes. This fact can then be used to generate percent level accurate nonlinear matter power spectra for a range of dark energy models.
March, 1 2017
 Dvorkin & Barausse, 2017, https://arxiv.org/abs/1702.06964, "The nightmare scenario: measuring the stochastic gravitationalwave background from stalling massive blackhole binaries with pulsartiming arrays"
 Masui et al., 2017, https://arxiv.org/abs/1702.06552, "Two and Threedimensional Probes of Parity in Primordial Gravity Waves"
 Hopkins et al., 2017, https://arxiv.org/abs/1702.06148, "FIRE2 Simulations: Physics versus Numerics in Galaxy Formation"
 Inayoshi et al. 2017, https://arxiv.org/abs/1702.06529, "Identifying stellar binary black hole formation channels from the imprint of their centerofmass acceleration in their gravitational wave signal"
 Shirasaki et al. 2017, https://arxiv.org/abs/1702.07085, "LargeScale Clustering as a Probe of the Origin and the Host Environment of Fast Radio Bursts"
 Bao et al, 2017, https://arxiv.org/abs/1702.06959, "Quantum Circuit Cosmology: The Expansion of the Universe Since the First Qubit"
 Dai & Venumadhav, 2017, https://arxiv.org/abs/1702.04724, "On the waveforms of gravitationally lensed gravitational waves"
 Our Ami Choi will discuss ways in which overlapping widearea surveys can be leveraged to investigate photometric redshift bias and shear multiplicative measurement bias based on various combinations of lensing and clustering crosscorrelations from spectroscopic, photometric and CMB surveys such as CFHTLenS, RCSLenS, KiDS, BOSS, WiggleZ, and Planck.
February, 15 2017
 Comparat et al., 2017, https://arxiv.org/pdf/1702.01628.pdf, "Accurate Mass and Velocity Functions of Dark Matter Halos"
 Busch et al., 2017, https://arxiv.org/pdf/1702.01682.pdf, "Assembly Bias and Splashback in Galaxy Clusters"
 Baxter et al., 2017, https://arxiv.org/pdf/1702.01722.pdf, "The Halo Boundary of Galaxy Clusters in the SDSS"
 Jang et al., 2017, https://arxiv.org/pdf/1702.01118.pdf, "The Tip of the Red Giant Branch Distance to Type IA Supernova Host Galaxies, and the Value of the Hubble Constant"
 Hoffman et al., 2017, http://www.nature.com/articles/s415500160036, "The dipole repeller"
February, 08 2017
 Guest speaker: David Cinabro, "Search For Type Ia Supernova NUVOptical Subclasses"
February, 01 2017
 Local speaker: Ashely Ross, "Things to consider when planning a largescale structure survey and how this relates to BOSS, eBOSS, DESI, and DES”
 Abbott et al., 2017, https://arxiv.org/pdf/1701.07709.pdf, "First Search for Gravitational Waves from Known Pulsars with Advanced LIGO"
 Klypin et al., 2017, https://arxiv.org/pdf/1701.05690.pdf, "Dark Matter Statistics for Large Galaxy Catalogs: Power Spectra and Covariance Matrices"
January, 25 2017
 Speaker: Susmita Adhikari, "Outskirts of Dark Matter Halos"
 Speaker: Kaze Wong, "Advanced LIGO lensing rate predictions"
January, 11 2017
 Castorina et al., 2017, https://arxiv.org/pdf/1609.05157.pdf, "On the spatial distribution of neutral hydrogen in the
Universe: bias and shotnoise of the HI Power Spectrum"
 Park et al., 2015, https://arxiv.org/pdf/1507.05353v2.pdf, "Joint Analysis of GalaxyGalaxy Lensing and Galaxy Clustering:
Methodology and Forecasts for DES"
 Bohm et al., 2017,https://arxiv.org/pdf/1701.01886.pdf, "Bayesian weak lensing tomography: Reconstructing the 3D largescale distribution of
matter with a lognormal prior"
 Chatterjee et al., 2017, https://arxiv.org/pdf/1701.01098.pdf, "The direct localization of a fast radio burst and its host"
 Marcote et al., 2017, https://arxiv.org/pdf/1701.01099.pdf, "The Repeating Fast Radio Burst FRB 121102 as Seen on Milliarcsecond Angular Scales"
 Tendulkar et al., 2017, https://arxiv.org/pdf/1701.01100.pdf, "The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102"
 Lingam & Loeb, 2017, https://arxiv.org/pdf/1701.01109.pdf, "Fast Radio Bursts from Extragalactic Light Sails"
December, 14 2016
 Hu and Joyce 2016, https://arxiv.org/abs/1612.02454, "Separate Universes beyond General Relativity"
 Baker and Trodden 2016, https://arxiv.org/abs/1612.02004, "MultiMessenger Time Delays from Lensed Gravitational Waves"
 LIGO 2016, https://arxiv.org/abs/1612.02029, "Upper Limits on the Stochastic GravitationalWave Background from Advanced LIGO's First Observing Run"
 LIGO 2016, https://arxiv.org/abs/1612.02030, "Directional limits on persistent gravitational waves from Advanced LIGO's first observing run"
 Modi et al. 2016, https://arxiv.org/abs/1612.01621, "Halo bias in Lagrangian Space: Estimators and theoretical predictions"
 Paranjape and Padmanabhan 2016, https://arxiv.org/abs/1612.02833, "Halo assembly bias from Separate Universe simulations"
 Brouwer et al. 2016, https://arxiv.org/abs/1612.03034, "First test of Verlinde's theory of Emergent Gravity using Weak Gravitational Lensing measurements"
 Fleury et al. 2016, https://arxiv.org/abs/1612.03726, "How does the cosmic largescale structure bias the Hubble diagram?"
 Sehgal et al. 2016, https://arxiv.org/abs/1612.03898, "Internal Delensing of Cosmic Microwave Background Acoustic Peaks"
 Bonus: Prof. Chris Hirata will give a short review on modified gravity.
December, 1 2016
November, 17 2016
Special talk:
Michael Wilson
University of Edinburgh
"Geometric and growth rate tests of gravity with the linearised galaxy distribution"
Abstract:
This talk will outline the consistency of the VIPERS PDR2 census of the galaxy distribution at z=0.8 with the expansion history and linear growth rate predicted by General Relativity and a Planck (2015) cosmology. These may be inferred from the observed anisotropy of the galaxy power spectrum, which is sensitive to both the coherent infall of galaxies towards clusters (outflow from voids) and the assumption of an expansion history differing from the true one.
I will then present the results of including a simple density transform prior to the analysis; this tackles the principal cause of nonlinearity by downweighting the most massive structures and extends the validity of theoretical models. Moreover, this weighting would amplify signatures of modified gravity in ‘shielded’ models and represents a higherorder statistic, which contains information beyond that available to the power spectrum.
Finally, the final data release of the VIPERS spectroscopic survey will be on Nov 18th ( http://vipers.inaf.it). I will detail the characteristics of the survey and describe the breadth of the accompanying clustering analyses.
 Rao et al. 2016, https://arxiv.org/abs/1611.04602, "Modeling the Radio Foreground for detection of CMB spectral distortions from Cosmic Dawn and Epoch of Reionization"
 Akitsu et al. 2016, https://arxiv.org/abs/1611.04723, "SuperSurvey Tidal Effect on Redshiftspace Power Spectrum"
 Hu et al. 2016, https://arxiv.org/abs/1611.04599, "Dark Cosmic Rays"
 Kitching et al. 2016, https://arxiv.org/abs/1611.04954, "The Limits of Cosmic Shear"
 Kovetz et al. 2016,https://arxiv.org/pdf/1611.01157.pdf , "The Black Hole Mass Function from Gravitational Wave Measurements"
November, 10 2016
 Patton et al. 2016, https://arxiv.org/abs/1611.01486, "Cosmological constraints from the convergence 1point probability distribution"
 Park et al. 2016, https://arxiv.org/abs/1611.02139, "The cosmological principle is not in the sky"
 Kovetz et al. 2016, https://arxiv.org/abs/1611.01157, "The Black Hole Mass Function from Gravitational Wave Measurements"
 Eggemeier et al. 2016, https://arxiv.org/abs/1611.01160, "Cosmology with Phase Statistics: Parameter Forecasts and Detectability of BAO"
 King and Lubin 2016, https://arxiv.org/abs/1606.04112, "Circular polarization of the CMB: Foregrounds and detection prospects"
 Review: CMB Circular Polarization
October, 27 2016
Special talk:
Patrick Breysse
John Hopkins University
"HighRedshift Astrophysics Using Every Photon"
Abstract:
Large galaxy surveys have dramatically improved our understanding of the complex processes which govern gas dynamics and star formation in the nearby universe. However, we know far less about the most distant galaxies, as existing highredshift observations can only detect the very brightest sources. Intensity mapping surveys provide a promising tool to access this poorlystudied population. By observing emission lines with low angular resolution, these surveys can make use of every photon in a target line to study faint emitters which are inaccessible using traditional techniques. With upcoming carbon monoxide experiments in mind, I will demonstrate how an intensity map can be used to measure the luminosity function of a galaxy population, and in turn how these measurements will allow us to place robust constraints on the cosmic star formation history. I will then show how crosscorrelating CO isotopologue lines will make it possible to study gas dynamics within the earliest galaxies in unprecedented detail.
October, 20 2016
October, 6 2016
September, 1 2016

