galaxies

Intrinsic Alignments Between Galaxies and the Cosmic Web at $z\sim 1-2$ in the IllustrisTNG Simulations

First author: Benjamin Zhang Galaxy formation theories predict that galaxy shapes and angular momenta have intrinsic alignments (IA) with the cosmic web, which provides an observational test of various theories, and is important to quantify as a nuisance parameter for weak lensing. We study galaxy IA in the IllustrisTNG suite of hydrodynamical simulations at redshifts 1 and 2, finding that alignment trends are consistent with previous studies. However, we find that the magnitude of the spin alignment signal is $\sim 2.

Mock Galaxy Surveys for HST and JWST from the IllustrisTNG Simulations

First author: Gregory F. Snyder We present and analyze a series of synthetic galaxy survey fields based on the IllustrisTNG Simulation suite. With the Illustris public data release and JupyterLab service, we generated a set of twelve lightcone catalogs covering areas from 5 to 365 square arcminutes, similar to several JWST Cycle 1 programs, including JADES, CEERS, PRIMER, and NGDEEP. From these catalogs, we queried the public API to generate simple mock images in a series of broadband filters used by JWST-NIRCam and the Hubble Space Telescope cameras.

Photometric redshift estimation of galaxies in the DESI Legacy Imaging Surveys

First author: Changhua Li The accurate estimation of photometric redshifts plays a crucial role in accomplishing science objectives of the large survey projects. The template-fitting and machine learning are the two main types of methods applied currently. Based on the training set obtained by cross-correlating the DESI Legacy Imaging Surveys DR9 galaxy catalogue and SDSS DR16 galaxy catalogue, the two kinds of methods are used and optimized, such as EAZY for template-fitting approach and CATBOOST for machine learning.

The origin of star-forming rings in S0 galaxies

First author: J. L. Tous Spatially resolved IFS maps in a sample of $532$ S0 galaxies from the MaNGA survey have unveiled the existence of inner rings ($\langle R\rangle\sim 1,R_\mathrm{e}$) betraying ongoing star formation in a number of these objects. Activity gradients averaged over bins of galactocentric radius up to $\sim 1.5,R_\mathrm{e}$ have been measured in the subspace defined by the first two principal components of the optical spectra of these galaxies.

Chasing ICM cooling and AGN feedback from the macro to the meso scales in the galaxy cluster ZwCl 235

First author: F. Ubertosi We aim to investigate the AGN/ICM interplay in ZwCl 235, a galaxy cluster with high X-ray flux, an extended central radio galaxy, and evidence of multi-phase gas at its center. Using archival data from the Chandra telescope, the VLASS survey, the LOTSS survey and the VLBA telescope, we perform a complete study of ZwCl 235, dissecting the dynamics of the ICM, the thermodynamic state of the central gas, and the properties of the BCG.

Constraining quenching timescales in galaxy clusters by forward-modelling stellar ages and quiescent fractions in projected phase space

First author: Andrew M. M. Reeves We forward-model mass-weighted ages (MWAs) and quiescent fractions in projected phase space (PPS), using data from the Sloan Digital Sky Survey, to jointly constrain an infall quenching model for galaxies in $\log(M_{\mathrm{vir}}/\mathrm{M}{\odot})>14$ galaxy clusters at $z\sim 0$. We find the average deviation in MWA from the MWA-$M\star$ relation depends on position in PPS, with a maximum difference between the inner cluster and infalling interloper galaxies of $\sim 1$ Gyr.

Deep Synoptic Array science I: discovery of the host galaxy of FRB 20220912A

First author: Vikram Ravi We report the detection and interferometric localization of the repeating fast radio burst (FRB) source FRB 20220912A during commissioning observations with the Deep Synoptic Array (DSA-110). Two bursts were detected from FRB 20220912A, one each on 2022 October 18 and 2022 October 25. The best-fit position is (R.A. J2000, decl. J2000) = (23:09:04.9, +48:42:25.4), with a 90% confidence error ellipse of $\pm2$ arcsec and $\pm1$ arcsec in right ascension and declination respectively.

DIGS: Deep Inference of Galaxy Spectra with Neural Posterior Estimation

First author: Gourav Khullar With the advent of billion-galaxy surveys with complex data, the need of the hour is to efficiently model galaxy spectral energy distributions (SEDs) with robust uncertainty quantification. The combination of Simulation-Based inference (SBI) and amortized Neural Posterior Estimation (NPE) has been successfully used to analyse simulated and real galaxy photometry both precisely and efficiently. In this work, we utilise this combination and build on existing literature to analyse simulated noisy galaxy spectra.

Dusty winds clear JWST super-early galaxies

First author: Fabrizio Fiore The JWST discovery of a number of super-early (redshift $z>10$), blue galaxies requires these systems to be essentially dust-free in spite of their large stellar masses. A possible explanation is that dust is evacuated by radiatively-driven outflows. We test this hypothesis by deriving the Eddington ratio, $\lambda_E$, for 134 galaxies at $6.5< z <16$. We find a strong anti-correlation between $\lambda_E$ and dust UV optical depth, $\tau_{1500} \propto \lambda_E^{-0.

Probing the Low-mass End of the Black Hole Mass Function via a Study of Faint Local Spiral Galaxies

First author: Michael S. Fusco We present an analysis of the pitch angle distribution function (PADF) for nearby galaxies and its resulting black hole mass function (BHMF) via the well-known relationship between pitch angle and black hole mass. Our sample consists of a subset of 74 spiral galaxies from the Carnegie-Irvine Galaxy Survey with absolute $B$-band magnitude $\mathfrak{M}{B}>-19.12$ mag and luminosity distance $D{\mathrm{L}} \leq 25.4$ Mpc, which is an extension of a complementary set of 140 more luminous ($\mathfrak{M}{B}\leq-19.