Upcoming and Previous Seminars (Past months or Previous years)

Note that if the talk's pdf or ppt is available after the talk, you can get it by clicking on the talk title.

Physics/Astronomy C290C Cosmology and Cosmology-BCCP Seminar
The Physics/Astronomy C290C series consists of the Cosmology-BCCP LBNL-Physics-Astronomy Cosmology seminars held Tuesdays 1:10-2:00 pm via ZOOM.
Please mail Joanne Cohn if you need the ZOOM login information (before 1 pm for sure, and the earlier the better), or to add to this list or to suggest speakers.

This seminar is intended for BCCP members and Berkeley graduate students pursuing their dissertation research in cosmology. Other LBL, Berkeley Astronomy and and Berkeley Physics Department members are welcome.

Speaker/Visitor Info is here.





BOSS and Nyx
(Image by C. Stark)

Note that there are also other talks which might be of interest, including:


December 2020
Dec 1, Tuesday
1:10 pm (BCCP/Cosmology)
Yun-Ting Cheng, Caltech
By ZOOM
Cosmology and Astrophysics with Intensity Mapping
Intensity mapping (IM) has emerged as a promising tool to study the high redshift universe and the faint, diffuse extragalactic populations. Without resolving individual galaxies, IM measures the integrated light from all sources and uses that to statistically probe the emission properties of the sources as well as the underlying large-scale structure they trace. In this talk, I will cover several topics on intensity mapping technique. First, I will introduce line intensity mapping (LIM), which probes the 3D large-scale structure of the universe, and a [C II] LIM experiment, TIME, that I am currently working on. Next I will talk about two recent projects on studying extragalactic background light (EBL), the aggregate emission from all extragalactic sources throughout cosmic time. I will present our latest stacking analysis results on probing the extended stellar halo with CIBER, a sounding rocket experiment that measures the near-IR EBL. Finally, I will conclude with future outlook for IM using SPHEREx, an upcoming all-sky near-infrared spectro-imaging survey.
Dec 9, Wednesday
12 noon (sharp, LBL DESI group lunch)
Mehdi Rezaie, OSU
By ZOOM






Past Months


July 2020
July 9, Thursday
4 pm (RPM LBL)
Kyle Dawson, Utah By ZOOM
“The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory”
The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) concluded observations of the cosmic distance scale and the growth of structure in February, 2019. The three dimensional clustering in all samples from the Sloan Digital Sky Survey (SDSS) was used to make 15 distinct, high precision measurements of Baryon Acoustic Oscillations (BAO) to an effective redshift z<2.4 and six measurements of redshift space distortions (RSD) to z<1.5. With this redshift coverage and sensitivity, the SDSS experiment is unparalleled in its ability to explore models of dark energy. Using available cosmological samples, we provide new constraints on the cosmological model with an emphasis on the role of the final BAO and RSD clustering measurements in advancing the cosmological model. In this talk, I will give a brief overview of the BAO and RSD measurements and present the highlights of the advances in modeling dark energy, the local expansion rate, tests of general relativity, neutrino masses, and the overall cosmological model.
Results webpages:
https://www.sdss.org/science/final-bao-and-rsd-measurements/
https://www.sdss.org/science/cosmology-results-from-eboss/

September 2020
Sep 1, Tuesday
1:10 pm (BCCP/Cosmology)
Elisa Chisari, Leiden
By ZOOM
Cosmology and galaxy evolution from galaxy shapes
Two phenomena contribute to correlating galaxy shapes across the Universe: the deviation of photons from a straight path due to the spacetime curvature ("gravitational lensing”), and tidal interactions (“intrinsic alignments”). Modelling both accurately is crucial to obtaining unbiased constraints on the cosmological model from forthcoming surveys, particularly in the context of elucidating the origin of accelerated expansion of the Universe. In this talk, I will cover recent advances in our understanding of the intrinsic alignments of galaxies. While these alignments are typically regarded as a contaminant to weak gravitational lensing, I will also discuss how they might become a cosmological and galaxy evolution probe of their own in the near future.
Sep 2, Wednesday
12 noon (sharp, LBL DESI group lunch)
Anand Raichoor, newly arriving
By ZOOM

Sep 8, Tuesday
1:10 pm (BCCP/Cosmology)
Omar Darwish, Cambridge
By ZOOM
Reconstructing cosmic mass with new CMB lensing methods
Current and future high significance CMB lensing-galaxy cross-correlations will soon precisely probe the growth of structure and provide powerful tests for parameter tensions, non-Gaussianity, and modifications to LCDM and gravity. However, such cross-correlations are sensitive to CMB foreground contamination, and the resulting biases represent an important challenge for cosmological analyses. In the first part of this talk, I will describe new CMB lensing cross-correlation measurements and new techniques to mitigate foreground effects in lensing maps. In particular, I will present a tSZ cleaned cross-spectrum between Atacama Cosmology Telescope lensing and BOSS galaxies using a modified version of the standard quadratic estimator that retains most of the signal-to-noise. I will also discuss work on upcoming correlations with Advanced ACT CMB lensing maps (which can reach up to 100 sigma significance) and on further improvements to foreground mitigation. In the second part of this talk, I will turn to the three-dimensional large scale structure of the Universe probed by galaxy surveys. I will show how we can reconstruct the large-scale density field from galaxy modes using CMB lensing-inspired methods and use this reconstruction to improve constraints on local non-Gaussianity.
Sep 10, Thursday
4 pm (LBL)
Yacine Ali-Haimoud, NYU
By ZOOM
"Hunting for Dark Matter in the Early Universe"
It is now well established that the dominant part of non-relativistic matter in the Universe is some substance which appears to be oblivious to any force but gravity. The nature of this dark matter remains a nagging puzzle, and several candidates remain in the running. For instance, dark matter might be a new particle, as light as an electron, which might weakly interact with standard particles. Or it could be partly made of primordial black holes as massive as many Suns, born in the very early Universe from the gravitational collapse of enhanced primordial fluctuations. In this talk, I will describe how one can try and tease out some of the properties of dark matter from the Cosmic Microwave Background (CMB), both through its frequency spectrum, and its angular fluctuations. After reviewing the basic physics underlying the CMB, I will highlight how it can constrain interacting particles and primordial black holes. If time allows, I will discuss what LIGO may be able to tell us about primordial-black holes.
Sep 15, Tuesday
1:10 pm (BCCP/Cosmology)
Ethan Nadler, Stanford/SLAC
By ZOOM
The Faintest Galaxies and Their Dark Matter Halos
As luminous tracers of the smallest dark matter halos, ultra-faint dwarf galaxies offer a unique window into the physics of galaxy formation and dark matter. Our census of these extremely faint systems has drastically improved in recent years as a result of detailed searches in deep photometric datasets, including those from the Dark Energy Survey. In this talk, we describe recent advances in our understanding of these systems, focusing on their implications for 1) the galaxy--halo connection, reionization physics, and high-redshift galaxy formation, and 2) the microphysical properties of dark matter. We show that the lack of a cutoff in the observed abundance of ultra-faint galaxies yields among the strongest astrophysical constraints to date on the warmth, Standard Model couplings, and de Broglie wavelength of dark matter, and we discuss the implications of these constraints for particle models including sterile neutrinos and ultra-light axions.
Sep 16, Wednesday
12 noon (sharp, LBL DESI group lunch)
Andres Salcedo, OSU
By ZOOM
Cosmological Forecasting with Cluster Cross-Correlations and Constraining Galaxy Assembly Bias in SDSS
Cluster weak lensing is a sensitive probe of cosmology, particularly the amplitude of matter clustering and matter density parameter. The main nuisance parameter in a cluster weak lensing cosmological analysis is the scatter between the true halo mass and the relevant cluster observable. We show that combining cluster weak lensing with the projected cluster-galaxy cross-correlation function and galaxy auto correlation function can break the degeneracy between cosmology and the cluster mass-observable relation to achieve tight, percent level constraints on the amplitude of matter clustering. For our fiducial scenario of combining these three observables measured over 0.3 - 30.0 Mpc/h, for clusters at z = 0.35-0.55, we forecast a 1.4% constraint on the amplitude of matter clustering while marginalizing over the scatter in the cluster mass-observable relation and all HOD parameters. I will present these and other results on cluster cosmology in the first section of the talk. In the second section of the talk I will discuss work on the connection between the properties and bias of haloes with their proximity to massive neighbors and more recent work on constraining the level of galaxy assembly bias in SDSS.
Sep 22, Tuesday
1:10 pm (BCCP/Cosmology)
Shivam Pandey, Penn
By ZOOM
Precise constraints on cosmology and gas physics: small scales modeling using DES, ACT and Planck
Small scale correlations between the tracers of large scale structure (LSS) carry the majority of the information but are challenging to model due to complex astrophysics. The correlations constructed out of galaxy positions, galaxy shear, and Sunyaev-Zeldovich effect can be used to constrain these processes. The first half of the talk will be focussed on describing galaxy clustering and galaxy-galaxy lensing correlations down to scales of 4Mpc/h using an effective perturbation theory model. I will describe the validation of the model using the DES-like simulations and its applications to the imminent cosmology results from DES Year 3 data. The second half will focus on describing the cross-correlations between shear/galaxy-positions from DES Year 3 data with the Compton-y maps from ACT and Planck. I will describe the constraints on the evolution of the average thermal energy of the Universe, preliminary constraints on the pressure profile, and comparison with hydrodynamical simulations.
Sep 24, Thursday
4 pm (LBL RPM)
Vivian Miranda, Arizona
By ZOOM
The Connected Universe: Relating Early, Intermediate and Late Universe with cosmological data
The standard model of cosmology is built upon a series of propositions on how the early, intermediate, and late epochs of the Universe behave. In particular, it predicts that dark energy and dark matter currently pervades the cosmos. Understanding the properties of the dark sector is plausibly the biggest challenge in theoretical physics. There is, however, a broad assumption in cosmology that the Universe in its earlier stages is fully understood and that discrepancies between the standard model of cosmology and current data are suggestive of distinct dark energy properties. Uncertainties on this hypothesis's validity are not usually taken into account when forecasting survey capabilities, even though our investigations might be obfuscated if the intermediate and early Universe did behave abnormally. In this colloquium, I propose a program to investigate dark energy and earlier aspects of our Universe simultaneously, through space missions in the 2020s in combination with ground-based observatories. This program will help guide the strategy for the future Rubin and Roman supernovae and weak lensing surveys. My investigations on how properties of the early and intermediate Universe affect inferences on dark energy (and vice-versa) will also support community understanding of how future missions can be employed to test some of the core hypotheses of the standard model of cosmology.
Sep 29, Tuesday
1:10 pm (BCCP/Cosmology)
Chun-Hao To, Stanford
By ZOOM
Cosmological constraints from a joint analysis of cluster abundances, galaxy correlations, and weak gravitational lensing in Dark Energy Survey
Three cosmic tracer fields are measured from imaging surveys: galaxy density, weak gravitation lensing shear, and cluster density. The joint analysis of the auto and cross correlations of the first two fields, often referred to as the 3x2pt analysis, has become a popular and competitive cosmological test of the standard cosmological model. The abundances and spatial distributions of galaxy clusters, which are associated with the highest peaks in the matter density field, provide another powerful probe of cosmic structure formation and evolution; thus, the combination of cluster abundances and 3x2pt analysis is expected to yield precise cosmological constraints. In the first part of the talk, I will present a novel multi-probe cluster cosmology analysis, which focuses exclusively on large scales. This new cluster cosmology analysis yields competitive cosmological constraints while being robust against several systematics. I will describe the extensive validation of the measurements, modeling, and inferences using N-body simulations populated with galaxies. In the second part of the talk, I will present cosmological constraints from the first joint analysis of cluster abundances and auto/cross correlations of all three cosmic tracer fields measured from the first year of the Dark Energy Survey (DESY1). The talk will be concluded by a discussion on the implication of the result, potential improvements, and expected constraining powers in the up-coming DESY3 analysis and future wide imaging surveys.

October 2020
Oct 6, Tuesday
1:10 pm (BCCP/Cosmology)
Christina Kreisch, Princeton
By ZOOM
Constraining Elusive Neutrino Properties Near and Far
Neutrinos remain an elusive component of the standard model, and constraining the sum of neutrino masses is a prominent goal in cosmology. But what if there are additional properties of this mysterious particle beyond the standard model? New physics in the neutrino sector might be necessary to address anomalies between different neutrino oscillation experiments. Intriguingly, it also offers a possible solution to the discrepant cosmological measurements of H_0. I will discuss our paper in which we delay the onset of neutrino free-streaming until close to the epoch of matter-radiation equality by introducing neutrino self-interactions in the presence of a non-vanishing sum of neutrino masses. Our analysis shows that it is possible to find radically different cosmological models that nonetheless provide excellent fits to the data, hence providing an impetus to thoroughly explore alternate cosmological scenarios. I will then discuss a large scale structure probe—cosmic voids—that can help us put constraints on the sum of neutrino masses. How neutrinos impact the scale at which voids cluster and the void correlation is sensitive to the tracers. The interplay of these neutrino signatures in the void abundance and clustering leaves a distinct fingerprint that could be detected with observations and potentially help break degeneracies between different cosmological parameters.
Oct 13, Tuesday
1:10 pm (BCCP/Cosmology)
Zack Li, Princeton
By ZOOM
Discovery from Millimeter-Wave Surveys in the Next Five Years
We're producing some exciting data with high-resolution ground-based observations at 27 - 280 GHz, from experiments like ACT, SPT, and (soon) SO. I'll discuss CMB data analysis and how these experiments will probe dark matter physics. I'll also talk about the astrophysics one can learn from these experiments, since they double as deep surveys of radio galaxies and Galactic dust, in both temperature and polarization.
Oct 14, Wednesday
12 noon (sharp, LBL DESI group lunch)
Sihan (Sandy) Yuan, Harvard
By ZOOM
Evidence for Galaxy Assembly bias in BOSS CMASS redshift-space 2PCF
We find the BOSS CMASS redshift-space 2PCF at small scale rejects the standard 5-parameter HOD, and strongly favors an extended HOD that incorporates both a concentration-based assembly bias and an environment-based assembly bias. The combination of the two assembly bias dependencies also seemingly alleviates the galaxy-galaxy lensing tension by predicting the lensing signal to within 1sigma of the observation. We suggest that the lensing tension can at least be partially explained by the lack of flexible galaxy-halo connection models and the lack of constraining power in the projected 2PCF.
Oct 15, Thursday
4 pm (LBL RPM)
Andrej Obuljen, Waterloo
By ZOOM
Anisotropic assembly bias in theory, simulations and BOSS data
Clustering of matter on large scales provides an important source of information on key cosmological parameters. To extract this information we need to understand the relation between the tracers we observe and the underlying matter field. The clustering strength of halos and galaxies on large scales is linearly biased compared to the matter clustering. This linear bias mainly depends on halo mass and redshifts, though selections based on other scalar halo properties (age, spin, concentration etc.) show additional bias dependences — called assembly bias. Furthermore, non-scalar halo properties: shapes, velocity dispersion and angular momentum, are correlated with the large-scale tidal field. Selection effects that couple to these non-scalar halo properties can produce anisotropic clustering even in real-space and act as a contaminant to redshift-space distortion measurements, through an anisotropic assembly bias (AB). I will discuss our recent results on studying the halo AB using a large number of numerical simulations. Then I will present the first detection of the galaxy anisotropic assembly bias in BOSS DR12 galaxies. Finally, I will show other consequences and future prospects.
Oct 20, Tuesday
1:10 pm (BCCP/Cosmology)
Stephon Alexander, Brown
By ZOOM
The Story of a Halo: Cosmic Inflation, Dark Genesis and Superfluid Halos
All matter, visible and dark, had to originate from some mysterious event in the early universe-baryogenesis and dark-genesis. This necessary physics goes beyond our standard cosmology and standard model of particle physics. In this colloquium I provide a pedagogical introduction to cosmic inflation, baryogenesis and argue the necessity of Chern-Simons theory in collaboration with the quantum dynamics of cosmic inflation (but not limited to it) to explain the coincidence between the density of dark and visible matter. A surprise regarding quantum coherence in halos awaits as a result.
Oct 21, Wednesday
12 noon (sharp, LBL DESI group lunch)
Ellen Hang, ROE
By ZOOM
Clustering in the Legacy Survey and its imprint on the CMB
Large Scale Structures can leave various imprints on the Cosmic Microwave Background. Two main features come from the spatial and temporal perturbations of the CMB photon trajectory due to LSS: weak lensing and the Integrated Sachs-Wolfe effect. I will give a summary of our paper "Galaxy clustering in Legacy Survey and its imprint on the CMB" (arXiv: 2010.00466), where we use the Legacy Imaging Survey to extract cosmological information from the above effects in the redshift range 0 < z < 0.8. The Legacy Survey, covering about a third of the sky area and containing tens of millions of galaxies, is excellent for the purpose of cross-correlation study, although a difficulty is to obtain robust redshift distribution for those galaxies given very limited photometric bands. In this study, we use our own method to find competitive photometric redshifts using colour information and construct galaxy density maps in four tomographic redshift slices. These maps are cross-correlated in angular space with the Planck 2018 lensing convergence and temperature maps. By comparing our measurements with theoretical predictions from the standard Lambda-CDM model assuming Planck 2018 Cosmology, we find that interestingly the lensing amplitude is lower than expected, consistent with the recently announced weak lensing results from the KiDS Survey. This may add to the existing tension in the Omega_m-sigma_8 parameter space.
Oct 27, Tuesday
1:10 pm (BCCP/Cosmology)
Johannes Lange, UCSC
By ZOOM
On the Cosmological Interpretation of Non-Linear Scales in BOSS and Beyond
The distribution of galaxies and matter in the Universe encodes a wealth of information about galaxies and cosmology. Particularly, measurements on non-linear scales are impacted by both galaxy physics and cosmology, making a cosmological interpretation more difficult. At the same time, measurements on non-linear have a higher precision than measurements on larger linear and quasi-linear scales. In this talk, I will present new, more robust analysis techniques for the cosmological study of non-linear scales. Additionally, I will discuss new cosmological interpretations of the non-linear and highly non-linear matter and galaxy distribution in the Baryon Oscillation Spectroscopic Survey (BOSS) LOWZ galaxy sample. Specifically, I will present new constraints on the growth-rate of the Universe via the study of the redshift-space galaxy correlation function. Additionally, I will discuss new findings on the mass and scale dependence of the galaxy-galaxy lensing tension with respect to CMB constraints. Finally, I will outline future directions in the study of non-linear scales.

November 2020
Nov 3, Tuesday
1:10 pm (BCCP/Cosmology)
NO Talk
By ZOOM

Nov 10, Tuesday
1:10 pm (BCCP/Cosmology)
Ana Diaz Rivero, Harvard
By ZOOM
Flow-based likelihoods for non-Gaussian inference
We investigate the use of data-driven likelihoods to bypass a key assumption made in many scientific analyses, which is that the true likelihood of the data is Gaussian. In particular, we suggest using the optimization targets of flow-based generative models, a class of models that can capture complex distributions by transforming a simple base distribution through layers of nonlinearities. We call these flow-based likelihoods (FBL). We analyze the accuracy and precision of the reconstructed likelihoods on mock Gaussian data, and show that simply gauging the quality of samples drawn from the trained model is not a sufficient indicator that the true likelihood has been learned. We nevertheless demonstrate that the likelihood can be reconstructed to a precision equal to that of sampling error due to a finite sample size. We then apply FBLs to mock weak lensing convergence power spectra, a cosmological observable that is significantly non-Gaussian (NG). We find that the FBL captures the NG signatures in the data extremely well, while other commonly-used data-driven likelihoods, such as Gaussian mixture models and independent component analysis, fail to do so. This suggests that works that have found small posterior shifts in NG data with data-driven likelihoods such as these could be underestimating the impact of non-Gaussianity in parameter constraints. By introducing a suite of tests that can capture different levels of NG in the data, we show that the success or failure of traditional data-driven likelihoods can be tied back to the structure of the NG in the data. Unlike other methods, the flexibility of the FBL makes it successful at tackling different types of NG simultaneously. Because of this, and consequently their likely applicability across datasets and domains, we encourage their use for inference when sufficient mock data are available for training.
Nov 17, Tuesday
1:10 pm (BCCP/Cosmology)
Jahmour Givans, OSU
By ZOOM
Modeling of the Lyman-alpha forest and weak lensing detector systematics
The Lyman-alpha forest is the primary cosmological tracer in the post-reionization Universe at 2 < z < 6. Many attempts have been made to model the Lyman-alpha flux fluctuation power spectrum using perturbation theory, but most of these either only model large (linear) scales or rely on fitting functions to capture small-scale (nonlinear) behavior. In the first part of this talk, I will present my work on using perturbation theory to model flux fluctuations at second order. I then show how this model refines our understanding of the importance of one BAO systematic, namely, early Universe streaming velocity between dark matter and baryons. In the second part of this talk, I will discuss my work on modeling infrared detector effects that are sources of systematics for Roman Space Telescope flight candidates. I then show how well our modeling performs against data and explain what it means for future weak lensing measurements.
Nov 18, Wednesday
12 pm (DESI talk)
Justin Myles, Stanford
By ZOOM
Leveraging Spectroscopy for Photometric Galaxy Survey Science
Large photometric galaxy surveys enable a broad range of science applications in astrophysics and cosmology, but suffer from challenges arising from the difficulty in constraining galaxy redshift. I will discuss two projects that leverage spectroscopic observations for a small subset of galaxies observed in wide field surveys to improve the utility of photometric datasets for cosmological experiments. First, I will show results using archival spectroscopy of redMaPPer galaxy clusters to measure the impact of projection effects on these clusters and comment on how this measurement relates to the DES Year 1 cluster cosmology results. Second, I will show the new methodology of and preliminary results for the DES Year 3 weak lensing source galaxy redshift calibration. Finally, I will discuss future applications of DESI data for these science goals, including active spare fiber proposals.
Nov 20, Friday
10 am INPA "double feature" (2x 30 min talks)
Anton Baleato Lizancos (Cambridge), and Utkarsh Giri (Perimeter Institute of Theoretical Physics)
By ZOOM
“Understanding biases to CMB lensing and delensing on the road to precision science” (Anton)
For cosmologists, CMB lensing can be both a blessing and a nuisance. It's a nuisance because it generates spurious B-mode polarisation which obscures the highly-sought-after signal from inflationary gravitational waves, but it's a blessing because it can be used to reconstruct maps of the projected matter distribution of the Universe, from which any physics affecting the growth of cosmic structure can be constrained. In this talk, I will focus on systematics that need to be addressed in order to harness the full statistical power of upcoming CMB experiments and make progress in both of these exciting areas. In the first part of my talk, I will briefly review the ways in which extragalactic emission from galaxies and clusters can bias CMB lensing reconstruction power spectra and cross-correlations with other tracers of the matter distribution. I will then present ongoing work on a novel approach where we model these biases analytically as a function of experimental characteristics, enabling improved physical insight, a quantification of theoretical uncertainties and potentially opening the door to improved mitigation methods. In the second part of the talk, I will explain how the lensing contamination to CMB B-modes can be removed — what is known as delensing — in order to facilitate searches for inflationary gravitational waves, and describe limitations of the commonly-used "template" approach to delensing. I will then briefly summarize preparatory efforts to delens data from the upcoming Simons Observatory. Finally, I will conclude by discussing biases affecting the procedure (and how to mitigate them) when lensing is reconstructed internally from the CMB itself, and in the alternative scenario where the CIB is used as a tracer of the matter.


“Exploring kSZ velocity reconstruction with N-body simulations and the halo model” (Utkarsh)
KSZ velocity reconstruction is a recently proposed method for mapping the largest-scale modes of the universe, by applying a quadratic estimator v̂ to the small-scale CMB and a galaxy catalog. We implement kSZ velocity reconstruction in an N-body simulation pipeline and explore its properties. We find that the reconstruction noise can be larger than the analytic prediction which is usually assumed. We revisit the analytic prediction and find additional noise terms that explain the discrepancy. The new terms are obtained from a six-point halo model calculation, and are analogous to the N(1) and N(3/2) biases in CMB lensing. We implement an MCMC pipeline which estimates fNL from N-body kSZ simulations and show that it recovers unbiased estimates of fNL, with statistical errors consistent with a Fisher matrix forecast. Overall, these results confirm that kSZ velocity reconstruction will be a powerful probe of cosmology in the near future, but new terms should be included in the noise power spectrum.
Nov 20, Friday
12 pm (INPA)
Liang Dai,UCB
By ZOOM
A New Window Into the Universe: Gravitational Waves From Compact Binary Coalescence
Detection of chirping gravitational waves (GWs) at ground-based laser interferometry observatories LIGO and Virgo have uncovered a population of compact binary mergers. Forthcoming observing runs with upgraded sensitivity and more observatories joining the network will tremendously increase the number of source systems, which will shed light on their astrophysical origin and enable to exploit those events as cosmological probes. I will present independent efforts by the IAS group to analyze the publicly available LIGO/Virgo data and report newly discovered GW events in addition to what experimental collaborations have reported. I will highlight several original and crucial data analysis methodologies we have developed for template matching, noise characterization and parameter estimation. In addition, I will give outlook on gravitational lensing of cosmological GW sources as expected from forthcoming observations and envisage its applications. I will explain our new findings of how wave propagation effects, measurable with GWs but unfeasible with usual electromagnetic sources, can allow extraction of unique information to reconstruct the lens or to probe non-luminous sub-galactic dark matter structures, thereby deepening our understanding of the matter distribution in the Universe.
Nov 24
1:10 pm (BCCP/Cosmology)
NO TALK

Previous years
   
   
            
 
  Privacy & Security Notice, etc.   Contact   Updated January 2016