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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 in room 131 Campbell Hall. Because this room is hard to keep clean, please don't bring your lunch (this is a change).
Please contact Joanne Cohn to add to this list or to suggest speakers.

Speaker/Visitor Info is here.





BOSS and Nyx
(Image by C. Stark)

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


November 2019
Nov 4, Monday
12:10 pm (TAC Seminar)
Mark Voit, MSU
Campbell 131
tba
Nov 5, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Guochao (Jason) Sun , Caltech
Campbell 131
Understanding cosmological evolution of galaxies with intensity mapping
Line-intensity mapping (LIM) is an emerging observational technique to study the large-scale structure of the universe. LIM measurements are sensitive to the aggregate line emission from the entire galaxy population, therefore placing important integral constraints on galaxy evolution in a cosmological context. In the first part of this talk, I will provide a status update of the Tomographic Ionized-carbon Mapping Experiment (TIME), a forthcoming instrument designed to measure the star formation rate during cosmic reionization by observing the redshifted 158-micron [CII] line in tomography. Over the same spectral coverage, it can simultaneously study the abundance of molecular gas during the era of peak star formation by observing the rotational CO lines. I will discuss the constraining power TIME will offer on various physical quantities, such as the escape fraction of ionizing photons and the evolution of cosmic molecular gas density. In the second part, I will present a simple, analytic framework to self-consistently model multiple emission lines in the context of using multi-line intensity mapping to dissect the multi-phase ISM of galaxies.
Nov 8, Friday
2 pm (INPA seminar), moved due to run-around
Solene Chabanier, IRFU, CEA, Universite Paris-Saclay
LBL 50-5132
Toward precision cosmology with the Lya forest
Neutral hydrogen in the Intergalactic Medium produces a collection of Lya absorptions, called the Lya forest, seen in the spectra of background objects. According to the common paradigm, neutral hydrogen in the IGM evolves from primordial density fluctuations in a low density and photo-ionized environment. It, therefore, acts as a direct tracer of Dark Matter (DM). However, it also implies that temperature and density are tightly coupled, giving rise to degeneracies between parameters describing either cosmology or the IGM thermal history. The Lya forest 1D power spectrum is sensitive to clustering on small scales, and as such to the smoothing scale of relativistic particles. It has been used to put the strongest constraints on the sum of the neutrino masses and to study DM models. To infer cosmological constraints and to test our models at the percent level accuracy, the measurements need to be compared to state-of-the-art hydrodynamical simulations. We also need to refine our understanding of the impact of galactic feedbacks on the IGM temperature.
I will present the analysis that leads to the most recent P1D measurement. As the current uncertainties are at the percent level, and will even shrink further in the DESI era, the P1D becomes sensitive to complex mechanical effects known as AGN feedback. We use Adaptative Mesh Refinement (AMR) hydrodynamical simulations, the Horizon-AGN and Horizon-noAGN simulations, to evaluate its impact on the P1D and prevent degeneracies with neutrino effects. Finally, I will present current constraints on the mass of active neutrinos and on Warm Dark Matter models.
Nov 12, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Anowar Shajib,UCLA
Campbell 131
Measuring the Hubble constant from time-delays of strongly lensed quasars
The recent tension between early- and late-Universe measurements of the Hubble constant highlights the necessity for independent and precise probes such as the time-delay cosmography. The measured time-delays between the lensed images of a background quasar depend on the absolute physical scales in the lens configuration. Thus, the time-delays allow measurements of these scales to infer the Hubble constant, H_0. Due to a number of great advancements over the past decade in both the data quality and modeling techniques, the measurement of H_0 from the time-delays has fulfilled its promise to be competitive with other traditional methods such as the cosmic distance ladder. This is evident from the recent 2.4% blind measurement of H_0 from only six lenses (Wong et al. 2019). Simulation shows that a sample of nine lenses shrinks the uncertainty on this measurement to 2% (Shajib et al. 2018). I will present the Hubble constant measured from a newly analyzed lens system taking the sample size to seven. In addition, I will present the future roadmap of time-delay cosmography to independently reach 1% precision within a few years.
Nov 19, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Selim Hotinli, Imperial
Campbell 131
Upcoming probes of fundamental physics: Utilising small-scale signatures in the Universe
In the next few years, the field of cosmology will see an influx of new and high quality data from surveys of cosmic microwave background (CMB) and large-scale structure (LSS). In particular, there is overwhelming evidence that measuring the late time effects on the CMB photons (secondaries) will provide new and valuable information for cosmological inference upon cross-correlating with LSS surveys. Simultaneously, surveys of the 21cm hydrogen line will achieve sufficient accuracy for cosmological inference for the fist time. In this talk, I will describe how these cosmological probes will provide opportunities to study fundamental problems. I will focus on the so-called ‘moving lens effect’, a CMB modulation due to changing gravitational potentials as a result of cosmological structure moving transverse to the line of sight (Hotinli et al 2019, PRL). I will also discuss prospects of utilising velocity acoustic oscillations (so-called VAOs) in the 21cm hydrogen line. I will describe how these observables can be used to constrain various classes of early Universe models beyond the standard LCDM.
Nov 26, Tuesday
no talk

December 2019
Dec 3, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Chia-Hsun Chuang, Stanford
Campbell 131
tba

January 2020
Jan 21, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Michelle Ntampaka, CfA
Campbell 131
tba
Jan 28, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Gus Evrard, Michigan
Campbell 131
tba

February 2020
Feb 4, Tuesday
1:10 pm (BCCP/Cosmology seminar)
held ,
Campbell 131
tba
Feb 11, Tuesday
1:10 pm (BCCP/Cosmology seminar)
held ,
Campbell 131
tba
Feb 18, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Marcelle Soares-Santos, Brandeis
Campbell 131
tba
Feb 25, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Boryana Hadzhiyska, Harvard
Campbell 131
tba

March 2020
Mar 3, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Daniel Gruen, SLAC/KIPAC
Campbell 131
tba
Mar 10, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Elena Massara, Waterloo
Campbell 131
tba
Mar 17, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Ben Thorne, UC Davis
Campbell 131
tba
Mar 24, Tuesday
No talk, spring break
Mar 31, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Adam Lidz , Penn
Campbell 131
tba

April 2020
Apr 7, Tuesday
1:10 pm (BCCP/Cosmology seminar)
,
Campbell 131
tba
Apr 14, Tuesday
1:10 pm (BCCP/Cosmology seminar)
,
Campbell 131
tba
Apr 21, Tuesday
1:10 pm (BCCP/Cosmology seminar)
,
Campbell 131
tba
Apr 28, Tuesday
1:10 pm (BCCP/Cosmology seminar)
,
Campbell 131
tba

May 2020
May 5, Tuesday
1:10 pm (BCCP/Cosmology seminar)
,
Campbell 131
tba





Past Months


July 2019
July 26, Friday
12 pm (INPA seminar)
Chen Heinrich, Caltech
LBL 50-5026
BAO and CMB Measurements of Compensated Isocurvature Perturbations and Implications for Tensions
CMB measurements have shown that the Universe started with mostly adiabatic perturbations: different particle species fluctuate spatially in the same way. The differences between fluctuations of species (called isocurvature) is highly constrained by Planck measurements, except for one type of isocurvature called Compensated Isocurvature Perturbations (CIPs), in which baryon density fluctuations are compensated by opposite dark matter density fluctuations and therefore hard to detect. In this talk, I will review various detection techniques with the CMB and propose a new measurement method by searching for a spatial modulations of the baryon acoustic oscillation (BAO) scale. We find that a Euclid-like survey would achieve WMAP CMB sensitivity while a cosmic-variance-limited BAO survey using emission-line galaxies up to z~7 has sensitivity between stage-3 and stage-4 CMB experiments. The results could be improved with a more optimal estimator and future 21cm measurements. Finally, if CIPs exist, they can bias cosmological measurements made assuming no CIPs, by acting as a super-sample fluctuation of the baryon density. I will show how a 1 sigma and isotropic (2 sigma and radial) CIP fluctuation maximally allowed by the current 95% Planck constraints can bias BAO measurements of H(z) at the 1% (6.6%) level, partially reducing the tension with the local measurements.

August 2019
Aug 26, Monday
12:10 pm (TAC Seminar)
Peng Oh, UCLA
Campbell 131
Cold Gas in Hot Halos: The Formation and Survival of Cold Gas in Galactic Halos
In recent years, observations of the circumgalactic medium has undercovered a large reservoir of T ~ 10^4 K, photoionized gas in the much hotter halos of galaxies. Inflowing cold gas in galactic halos helps fuel star formation, whilst outflowing cold gas is our primary observational marker of feedback. However, the formation and survival of dense cold gas in the atmospheres of galaxy halos is still poorly understood. For instance, we do not yet understand how cold gas can be entrained in a hot wind, as is observed; most simulations indicate it should be shredded by hydrodynamic instabilities. The impact of a multi-phase medium on cosmic ray propagation and feedback in the halo is also poorly understood. In this talk I will highlight some recent progress on these questions.

September 2019
Sep 3, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Georgios Valogiannis, Cornell
Campbell 131
“Testing gravity with cosmology: efficient simulations, novel statistics and analytical approaches"
In the era of precision cosmology, a wide range of cosmological surveys, such as the LSST, DESI, Euclid and WFIRST will precisely probe the large-scale structure of the universe, shedding light on the nature of the dark sectors. Given how sensitively the growth of structure depends on the nature of the underlying gravitational field, this will be a unique opportunity to constrain the so-called Modified Gravity models (MG), that are theoretical alternatives to dark energy, which attempt to explain cosmic acceleration through a large-scale modification to general relativity. In order to fully utilize the wealth of incoming data, however, theoretical predictions of structure formation in such alternative scenarios are necessary. Due to the existence of an additional degree freedom, that these models introduce, N-body simulations prove to be highly computationally expensive. In the first part of the talk, I will discuss how we can overcome this issue by using Lagrangian hybrid techniques, which can lead to a speed-up by 2 orders of magnitude. Then I will proceed to introduce novel statistics that can help us more confidently detect MG signals hidden in cosmic density fields, by up-weighting the significance of cosmic voids, where the MG-ΛCDM degeneracy is broken. When structure formation is analytically tractable, finally, I will show that we can make accurate analytical predictions for the two-point statistics using Lagrangian perturbation theory and the Gaussian Streaming Model, simultaneously capturing the effects of both halo-bias and redshift space distortions, effects crucial in the context of spectroscopic surveys, for the first time in modified gravity.
Sep 5, Thursday
4 pm (RPM)
David Schlegel, LBL
LBL 50-5132
MegaMapper: a spectroscopic instrument for the study of Inflation and Dark Energy
MegaMapper is a proposed ground-based experiment to measure Inflation parameters and Dark Energy from galaxy redshifts at 2 < z <5. A 6.5-m Magellan telescope coupled with DESI spectrographs achieves a multiplexing of 20,000. MegaMapper would be located at Las Campanas Observatory to fully access LSST imaging for target selection.
Sep 9, Monday
12:10 pm (TAC Seminar)
Rick Mebane, UCLA
Campbell 131
Population III Star Formation and the Cosmic 21-cm Background
The first generation of stars to have formed in the universe were likely very different than the stars we observe today. These Population III stars formed from pristine gas with no metals, and their formation was crucial to the early evolution of galaxies. While we have yet to observe a Population III star forming halo directly, we may be able to see them indirectly through their supernovae or their effect on the cosmological 21-cm background. I will present a set of semi-analytic models studying the formation of these Population III stars and the transition of their halos to metal-enriched star formation. I will also discuss the prospects of observing this mode of star formation, focusing on their effect on the cosmological 21-cm background and comparing our results to the recent claimed detection of a 21-cm signal by the EDGES experiment.
Sep 10, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Phil Mansfield, Chicago
Campbell 131
Why Do Dark Matter Haloes Die Together? The Causes of Halo Assembly Bias at Galaxy Masses
At a constant mass, old dark matter haloes and young dark matter haloes cluster differently from one another. This fact, known as "assembly bias," severely complicates the construction of mock catalogues and serves as a major challenge for structure formation models. In this talk, I test and synthesize the many competing explanations for this phenomenon into a single cohesive story with a strong focus on low mass haloes.
Sep 13, Friday
12 pm (INPA seminar)
Suhail Dhawan, Stockholm
LBL 50-5026
Dark energy and the Hubble constant with standard candles and standard clocks
In this talk, I will summarise our recent results on constraining dark energy and measuring the local expansion rate, i.e. the Hubble constant, with Type Ia supernovae and gravitationally lensed transients. Despite growing evidence of accelerated expansion of the universe, the physical mechanism driving this phenomenon is poorly understood. Using geometric probes, we find no significant evidence suggesting a paradigm outside standard cosmology, i.e. dark energy as a cosmological constant, however, we obtain moderate evidence disfavouring some of the non-standard models.
Sep 17, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Tae-Hyeon Shin , Penn
Campbell 131
The boundary of galaxy clusters and its implications on SFR quenching of satellite galaxies”
Infalling particles form a sharp physical boundary around their first apocenters around the parent halo, which is called "splashback radius". The previous measurements of splashback radius using optical clusters reported a ~20% discrepancy against the theory prediction. Here, using galaxy clusters detected by SZ surveys (ACT, SPT), we present the detection of the splashback radius and its consistency with respect to N-body simulations, by cross-correlating the galaxy clusters to the DES galaxies. On the other hand, it is known that the infalling galaxies around galaxy clusters experience enhanced star formation quenching. Using galaxy samples split on their colors, we also present the possibility of constraining the quenching parameters in quenching models we adopt (e.g. quenching timescale), making use of N-body simulations.
Sep 19, Thursday
3:45 pm (Astronomy Colloquium)
Matt Dobbs, McGill
LeConte 1
A New Era of Transients and Cosmic Structure on the Radio Sky
Technology advances have opened a new era of radio observations. We are now monitoring the sky at millisecond cadence and discovering a vast catalog of new fast radio transients while simultaneously making deep maps of structure in the universe using hydrogen intensity mapping as a tracer. While these fields are still in their infancy, early results are rolling out, fuelling discovery and motivating the design for new instruments.
I will present an overview of the Canadian Hydrogen Intensity Mapping Experiment (CHIME), describing the project's status and early results. I’ll conclude by introducing the next generation experiment, CHORD, now being designed.
Sep 23, Monday
12:10 pm (TAC seminar)
Christopher Reynolds, Cambridge
131 Campbell
Particle physics beyond the Standard Model (and other fun) with clusters of galaxies
Clusters of galaxies provide superb laboratories for exploring new particle physics. They represent the most massive dark matter objects in the Universe, making them an important laboratory for probing dark matter decay and annihilation signatures. However, in this talk, I will highlight how the transparency (or lack thereof) of the magnetized intracluster medium (ICM) to X-rays can be a powerful probe of axion-sector physics. I will present new data from the Chandra X-ray Observatory for the Perseus cluster which already allows us to set constraints on the existence of low-mass axion-like particles which exceed those possible from the next-generation laboratory and ground-based searches. After discussing the future prospects and limitations of these studies, I will briefly discuss the other astrophysical implications of the new Chandra data for our understanding of AGN feedback and fuelling in Perseus.
Sep 24, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Keir Rogers, Nordita
Campbell 131
Tests of new physics with the Lyman-alpha forest
The Lyman-alpha forest (the correlated absorption seen in the spectra of high-redshift quasars) is a uniquely powerful probe of new physics in the cosmological model — whether that be properties of the neutrino, the nature of cosmic inflation or the phenomenology of dark matter. The challenge lies in robustly disentangling the cosmology and the astrophysics of the intergalactic medium from which it is sourced. I will discuss new models and methods that can achieve the statistical inference sufficiently accurate for current and upcoming spectroscopic surveys (e.g., eBOSS, DESI). These exploit the most sophisticated simulations of the Universe to-date and innovative machine-learning algorithms (Bayesian emulator optimisation). Deviation from the standard model of cold, collisionless dark matter would leave a characteristic suppression in the linear matter power spectrum that the Lyman-alpha forest can reveal. I will present preliminary bounds on the shape of this suppression and discuss the implications for the allowed range of dark matter candidates.
Sep. 27, Friday
12 noon (INPA talk)
Romain Graziani, Universite Blaise Pascal
LBL 50-5132
Peculiar Velocities in Cosmology
The Universe is not homogenous. Since the early times, its structures have grown and moved under the laws of gravity. By measuring these motions today we are able to trace the history of the Universe expansion and gravity laws and hence test the General Relativity. Peculiar velocity measurements rely on precise extragalactic distances estimation, which can be provided by type Ia supernovae observations. Because peculiar velocities of galaxies are deviations from the Hubble expansion law, they have poor signal to noise ratio and are particularly sensible to usual systematic uncertainties such as calibration errors, selection effects and unknown covariances. During this presentation I will show how a precise forward modeling of observations allow us to overcome these caveats and that peculiar velocities analyses can be considered as a powerful cosmological probe. In particular, I will detail how the statistical methods I developed during my thesis can handle extragalactic distance measurements and lead to - e.g. - a velocity field reconstruction of our Local Universe from Type Ia Supernovae, so as constraints on General Relativity.

October 2019
Oct 1, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Jose Manuel Zorrilla Matilla, Columbia
Campbell 131
Learning from small scales in weak lensing and CMB data
Weak lensing of photons by large scale structure is sensitive to both the growth of the (lensing) structures and the expansion history of the universe. The large number of modes available on small scales have the potential to constrain cosmological parameters beyond what is achievable in the linear regime, but extracting this information from weak lensing surveys is not straightforward. I will review how to do so emphasizing the use of non-Gaussian observables and discuss how deep convolutional neural networks offer a viable alternative. The amount of information is limited by our ability to model the matter density field on small scales, including baryonic effects. I will end by explaining how future high resolution CMB experiments can inform simulations by measuring the angular momentum of baryons in the circumgalactic medium.
Oct 4, Friday
12 pm (INPA seminar)
Daniel Whiteson, UCI
LBL 50-5132
What has the Machine Learned?
Recent advances in artificial intelligence offer opportunities to disrupt the traditional techniques for data analysis in high energy physics. I will describe the new machine-learning techniques, explain why they are particularly well suited for particle physics, present selected results that demonstrate their new capabilities, and present a strategy for translating their learned strategies into human understanding.
Oct 7, Monday
12:10 pm (TAC seminar)
Wolfgang Kerzendorf, MSU
Campbell 131
"Machine learning and theoretical astrophysics"
Machine Learning is currently one of the hot new topics of our time. Advancements in computing and algorithms have made incredible progress. However, the paradigms of machine learning are often seemingly at odds with our goals as physicists: Machine-learning techniques techniques are used to interpolate and extrapolate from given large data sets without prior knowledge. Physical analysis applies statistical methods and prior physical understanding to large data sets to infer the fundamental laws shaping them. While there are differences between these too approaches there are also many commonalities.
In this talk, I will showcase several examples how machine learning can aid in astrophysics research. Specifically, I will focus on the area of data model comparisons and exploration of parameter spaces: High computing costs limit the exploration of the high-dimensional spaces required to understand the details in today’s astrophysical problems. Exploring the full viable parameter space is often needed to reliably identify new mechanisms. A good example for this is the modelling the spectral time series. The expensive radiative transfer codes needed to find the complex mechanisms are too expensive to marginalize the high dimensional parameter space. Physical models are mostly continuous allowing parameter interpolation. Emulators are machine learning con- structs that combine dimensionality reduction with interpolation algorithms. These constructs are geared towards exploration of high dimensional spaces with a minimum of pre-computed grid points. Some emulators even feature means to quantify the uncertainty that arises due to interpolation.
I will conclude my talk by giving an outlook of the possible future synergies of machine learning and theoretical astrophysics.
Oct 8, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Digvijay Wadekar, NYU
Campbell 131
"Analytic covariance of the redshift-space galaxy power spectrum"
A robust analysis of the covariance of the galaxy power spectrum is crucial for cosmological parameter estimation. The traditional process of obtaining the covariance involves simulating thousands of mocks. I will present an analytic approach for the full covariance matrix which is more than four orders of magnitude faster than mocks. Our analytic approach includes shot noise, redshift-space distortions, higher-order galaxy bias and non-linear structure formation. The dominance of shot noise at quasi-linear scales greatly simplifies the analytic approach and makes it useful for future surveys like DESI and Euclid. I will also show that the effect of super-survey modes for a redshift survey is stronger than previously considered in the literature.
Oct 15, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Lucas Secco, Penn
Campbell 131
"Cosmic Shear in the Year-3 DES data: 2-point and 3-point correlations"
The cosmology analyzes of the Year-3 (Y3) data from the Dark Energy Survey (DES) is at full speed ahead. Our preliminary weak lensing sample contains 120 million objects over 4200 square degrees of sky and is the largest shape catalog to date. This statistical power comes at a price: the cosmic shear measurements are more sensitive not only to the signal but also to potential systematics. In this talk, I will present our prospects for the 2-point cosmic shear cosmology analysis and some of the leading systematics that must be under control, in particular the Intrinsic Alignment of galaxies. Additionally, I will talk about a preliminary detection of a shear 3-point correlation in the DES-Y3 simulations and data which is unprecedented in weak lensing surveys.
Oct 22, Tuesday
1:10 pm (BCCP/Cosmology seminar)
George Stein, UCB
Campbell 131
Mocking the Universe & Machine Learning Approaches to Large-Scale Structure
Efficient generation of accurate mock observations of the sky, tailored specifically to near-future large-scale structure and cosmic microwave background surveys, is a key technical challenge in cosmology. I will first discuss the creation of these synthetic observations, or mocks, through the use of rapid so-called ‘approximate’ simulation techniques, with a focus on the Websky extragalactic CMB simulations. Next, I will overview a few recent applications of machine learning in cosmology, including the use of deep learning techniques to speed up cosmological simulations, and the possible failure of supervised methods when trained on mocks with the goal of extracting information from data.
Oct 23, Wednesday
2 pm (Particle Seminar)
Francis Yan Cyr-Racine, UNM
LBL 50 5132
Rock 'n' Roll, Jazzy and Classical Solutions to the Hubble Tension
Local measurements of the Hubble parameter are increasingly in tension with the value inferred from a LCDM fit to the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) data. A general class of solutions to this tension involves temporarily increasing the energy density of the Universe close to the epoch of matter-radiation equality to reduce the size of the baryon-photon sound horizon at recombination. In the literature, various models for this energy injection have been proposed, ranging from rolling and oscillating scalar fields, new relativistic species with nonstandard properties, or extra matter components that subsequently decay. We describe the appealing and problematic features of these proposed solutions, showing that it is in general challenging to resolve the tension between CMB, BAO, and distance ladder measurements without either introducing new tensions with other cosmological datasets or requiring particle physics models that are significantly fine-tuned. We argue that none of the currently proposed solutions are entirely satisfactory, but identify important properties that a complete solution should have.
Oct 29, Tuesday
1:10 pm (BCCP/Cosmology seminar)
Patricia Larsen, ANL
Campbell 131
From dark matter to observed skies, creating a universe with state-of-the-art simulations
Preparations for upcoming cosmological surveys such as LSST can benefit greatly from the use of simulated observations, however creating realistic galaxy catalogs is an incredibly complex and challenging task. In this talk I will first discuss how such simulations can aid in the interpretation of modern cosmological datasets. I will then detail the creation of the cosmoDC2 synthetic sky catalog built for the LSST-DESC collaboration, with a particular focus on the development of the weak lensing pipeline. Finally I will discuss lessons learnt in the context of a future synthetic galaxy catalog currently in the early stages of development.

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