Dhayaa Anbajagane
A5072003246- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- CCD and CMOS Imaging Sensors
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Advanced Data Storage Technologies
- Plant Water Relations and Carbon Dynamics
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Data Visualization and Analytics
- Computational Physics and Python Applications
- Neural Networks and Applications
- Statistical and numerical algorithms
- Neutrino Physics Research
- Spacecraft and Cryogenic Technologies
- Face and Expression Recognition
- Gas Dynamics and Kinetic Theory
University of Chicago
2021-2025
Netherlands Institute for Radio Astronomy
2023-2025
Electronics for Imaging (United States)
2025
Fermi National Accelerator Laboratory
2024
University of Michigan
2018-2021
Abstract We report the discovery and spectroscopic confirmation of an ultra-faint Milky Way satellite in constellation Leo. This system was discovered as a spatial overdensity resolved stars observed with Dark Energy Camera (DECam) data from early version third release DECam Local Volume Exploration (or DELVE) survey. The low luminosity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>V</mml:mi>...
We introduce \textsc{Gizmo-Simba}, a new suite of galaxy cluster simulations within \textsc{The Three Hundred} project. consists zoom re-simulations 324 clusters with $M_{200}\gtrsim 10^{14.8}M_\odot$ drawn from the MultiDark-Planck $N$-body simulation, run using several hydrodynamic and semi-analytic codes. The \textsc{Gizmo-Simba} adds state-of-the-art formation model based on highly successful {\sc Simba} mildly re-calibrated to match $z=0$ stellar properties. Comparing zooms...
Beyond-two-point statistics contain additional information on cosmological as well astrophysical and observational (systematics) parameters. In this methodology paper we provide an end-to-end simulation-based analysis of a set Gaussian non-Gaussian weak lensing using detailed mock catalogs the Dark Energy Survey (DES). We implement: 1) second third moments; 2) wavelet phase harmonics (WPH); 3) scattering transform (ST). Our is fully based simulations, it spans space seven νwCDM parameters,...
We present a simulation-based cosmological analysis using combination of Gaussian and non-Gaussian statistics the weak lensing mass (convergence) maps from first three years (Y3) Dark Energy Survey (DES). implement: 1) second third moments; 2) wavelet phase harmonics; 3) scattering transform. Our is fully based on simulations, spans space seven $\nu w$CDM parameters, forward models most relevant sources systematics inherent in data: masks, noise variations, clustering sources, intrinsic...
ABSTRACT We search for the signature of cosmological shocks in stacked gas pressure profiles galaxy clusters using data from South Pole Telescope (SPT). Specifically, we stack latest Compton-y maps 2500 deg2 SPT-SZ survey on locations identified that same set. The sample contains 516 with mean mass $\langle M_{\rm 200m}\rangle = 10^{14.9} \, {\rm M}_\odot$ and redshift 〈z〉 0.55. analyse parallel a set zoom-in hydrodynamical simulations three hundred project. show two features: (i) deficit at...
Abstract Primordial non-Gaussianities (PNGs) are signatures in the density field that encode particle physics processes from inflationary epoch. Such have been extensively studied using Cosmic Microwave Background, through constraining their amplitudes, f X NL , with future improvements expected large-scale structure surveys; specifically, galaxy correlation functions. We show weak lensing fields can be used to achieve competitive and complementary constraints. This is shown via Ulagam suite...
Widefield surveys of the sky probe many clustered scalar fields -- such as galaxy counts, lensing potential, gas pressure, etc. that are sensitive to different cosmological and astrophysical processes. Our ability constrain processes from these depends crucially on statistics chosen summarize field. In this work, we explore cumulative distribution function (CDF) at multiple scales a summary convergence Using suite N-body lightcone simulations, show CDFs' constraining power is modestly better...
We study stellar property statistics, including satellite galaxy occupation, of massive halo populations realized by three cosmological hydrodynamics simulations: BAHAMAS + MACSIS, TNG300 the IllustrisTNG suite, and Magneticum Pathfinder. The simulations incorporate independent sub-grid methods for astrophysical processes with spatial resolutions ranging from $1.5$ to $6$ kpc, each generates samples $1000$ or more halos $M_{\rm halo}> 10^{13.5} M_{\odot}$ at redshift $z=0$. Applying...
ABSTRACT In a purely cold dark matter (CDM) universe, the initial power spectrum and its subsequent gravitational growth contain no special mass- or time-scales, so neither do emergent population statistics of internal (DM) halo properties. Using 1.5 million haloes from three illustristng realizations ΛCDM we show that galaxy formation physics drives non-monotonic features (‘wiggles’) into DM property across six decades in mass, dwarf galaxies to clusters. We characterize these by extracting...
ABSTRACT The Sunyaev–Zeldovich (SZ) effect is a powerful tool in modern cosmology. With future observations promising ever improving SZ measurements, the relativistic corrections to signals from galaxy groups and clusters are increasingly relevant. As such, it important understand differences between three temperature measures: (a) average (rSZ) temperature, (b) mass-weighted relevant for thermal (tSZ) effect, (c) X-ray spectroscopic temperature. In this work, we compare these cluster...
ABSTRACT We apply machine learning (ML), a powerful method for uncovering complex correlations in high-dimensional data, to the galaxy–halo connection of cosmological hydrodynamical simulations. The mapping between galaxy and halo variables is stochastic absence perfect information, but conventional ML models are deterministic hence cannot capture its intrinsic scatter. To overcome this limitation, we design an ensemble neural networks with Gaussian loss function that predict probability...
The physics of baryons in halos, and their subsequent influence on the total matter phase space, has a rich phenomenology must be well understood order to pursue vast set questions both cosmology astrophysics. We use CAMELS simulation suite quantify impact four different galaxy formation parameters/processes (as as two cosmological parameters) concentration-mass relation, $c_{\rm vir} - M_{\rm vir}$. construct simulation-informed nonlinear model for concentration function halo mass,...
ABSTRACT We search for signatures of cosmological shocks in gas pressure profiles galaxy clusters using the cluster catalogues from three surveys: Dark Energy Survey (DES) Year 3, South Pole Telescope (SPT) SZ survey, and Atacama Cosmology (ACT) data releases 4, 5, 6, thermal Sunyaev–Zeldovich (SZ) maps SPT ACT. The combined sample contains around 105 with mass redshift ranges $10^{13.7} \lt M_{\rm 200m}/\, {\rm M}_\odot 10^{15.5}$ 0.1 &lt; z 2, total sky coverage is $\approx 15\, 000...
Upcoming cosmic shear analyses will precisely measure the matter distribution at low redshifts. At these redshifts, is affected by galaxy formation physics, primarily baryonic feedback from star and active galactic nuclei. Employing measurements Magneticum IllustrisTNG simulations a dark + baryon (DMB) halo model, this paper demonstrates that Sunyaev-Zel'dovich (SZ) effect observations of clusters, whose masses have been calibrated using weak gravitational lensing, can constrain impact on...
The underlying physics of astronomical systems governs the relation between their measurable properties. Consequently, quantifying statistical relationships system-level observable properties a population offers insights into astrophysical drivers that class systems. While purely linear models capture behavior over limited range system scale, fact astrophysics is ultimately scale-dependent implies need for more flexible approach to describing statistics wide dynamic range. For such...
The halo concentration-mass relation has ubiquitous use in modeling the matter field for cosmological and astrophysical analyses, including imprints from galaxy formation physics is tantamount to its robust usage. Many however, probe around halos selected by a given halo/galaxy property – rather than mass under each selection choice can be different. We employ CAMELS simulation suite quantify astrophysics cosmology dependence of relation, , when on five properties: (i) velocity dispersion,...
Statistics that capture the directional dependence of baryon distribution in cosmic web enable unique tests cosmology and astrophysical feedback. We use constrained oriented stacking thermal Sunyaev-Zel'dovich (tSZ) maps to measure anisotropic hot gas $2.5-40$ Mpc away from galaxy clusters embedded massive filaments superclusters. The cluster selection orientation (at a scale $\sim15$ Mpc) Dark Energy Survey (DES) Year 3 data, while expanded tSZ Atacama Cosmology Telescope Data Release 6...
Synthetic source injection (SSI), the insertion of sources into pixel-level on-sky images, is a powerful method for characterizing object detection and measurement in wide-field, astronomical imaging surveys. Within Dark Energy Survey (DES), SSI plays critical role all necessary algorithms used converting images to catalogs, deriving quantities needed cosmology analysis, such as rates, galaxy redshift estimation, magnification, star-galaxy classification, photometric performance. We present...
We describe the photometric data set assembled from full six years of observations by Dark Energy Survey (DES) in support static-sky cosmology analyses. DES Y6 Gold is a curated derived Data Release 2 (DR2) that incorporates improved measurement, calibration, object classification and value added information. comprises nearly $5000~{\rm deg}^2$ $grizY$ imaging south Galactic cap includes 669 million objects with depth $i_{AB} \sim 23.4$ mag at S/N $\sim 10$ for extended top-of-the-atmosphere...
Abstract Anisotropy properties—halo spin, shape, position offset, velocity and orientation—are an important family of dark matter halo properties that indicate the level directional variation internal structures halos. These reflect dynamical state halos, which in turn depends on mass assembly history. In this work, we study evolution anisotropy response to merger activity using IllustrisTNG simulations. We find trajectories significantly deviate from secular evolution. have same qualitative...
Galaxy cluster masses, rich with cosmological information, can be estimated from internal dark matter (DM) velocity dispersions, which in turn observationally inferred satellite galaxy velocities. However, galaxies are biased tracers of the DM, and bias vary over host halo properties as well time. We precisely calibrate bias, b_v -- defined ratio DM dispersions a function redshift, mass, stellar mass threshold (Mstarsat), for massive halos (M200c > 1e13.5 msun) five simulations:...
Abstract Upcoming cosmic shear analyses will precisely measure the matter distribution at low redshifts. At these redshifts, is affected by galaxy formation physics, primarily baryonic feedback from star and active galactic nuclei. Employing measurements Magneticum IllustrisTNG simulations a dark + baryon (DMB) halo model, this paper demonstrates that Sunyaev-Zel'dovich (SZ) effect observations of clusters, whose masses have been calibrated using weak gravitational lensing, can constrain...