arXiv subjects

Eshita Banerjee

Publications and source records attributed to Eshita Banerjee.

4 recordsLinked to original sources

arXiv2026

MUSEQuBES: Investigating the Physical and Chemical Properties of Circumgalactic Gas Around Ly$α$ Emitters at $z \approx 3.3$

We present a detailed study of the physical properties of absorbers associated with $z\approx3.3$ \lya\ emitters (LAEs) from the MUSEQuBES survey. Using \HI\ and ionic column densities derived from Voigt profile fitting, we determine the density and metallicity of 75 absorbers associated with 59 LAEs through a custom-built Bayesian framework. The overall sample shows a median density $\log\,(n_{\rm H}/{\rm cm^{-3}})=-2.7\pm0.7$ and metallicity \met$=-1.6^{+1.2}_{-0.9}$ with $\approx15\%$ ($\approx 40\%$ including upper limits) of systems showing metallicities consistent with the IGM at these redshifts (\met$\lesssim -2.8$). Intriguingly, absorbers with $\log\, N(\rm HI)/{\rm cm^{-2}} \gtrsim 16.5$, corresponding to an overdensity of $\sim 100$ at $z=3$, exhibit a bimodal metallicity distribution with peaks at \met$=-3.8\pm 0.2$ and $-1.8\pm 0.6$. The latter are observed at large impact parameters ($\gtrsim150$~pkpc) and often exhibit low-ionization species (e.g., \SiII, \AlII). We interpret the former as pristine inflowing gas from the cosmic web, while the latter likely traces metal-enriched CGM associated with outflows from faint galaxies not detected in Ly$α$ emission. We find no significant correlations between absorber metallicity or density and host galaxy properties, including redshift, impact parameter, SFR, Ly$α$ luminosity, or environment. Absorbers separated by $\lesssim500$~\kms\ show $\sim$1~dex metallicity and $\sim$0.5~dex density variations, indicating physical and chemical inhomogeneity of the medium around these LAEs.

astro-ph.GA↗

arXiv2025

MUSEQuBES: Connecting HI absorption with Ly$α$ emitters at $z \approx 3.3$

We present a comprehensive analysis of HI absorption around 96 lya emitters (LAEs) at $z\approx3.3$ (median lya luminosity $\approx10^{42}$ erg.s$^{-1}$). These LAEs were identified within 8 MUSE fields, each $1'\times1'$ on the sky and centered on a bright background quasar, as part of the MUSEQuBES survey. Using Voigt profile fitting for all HI absorbers detected within $\pm500$ km.$s^{-1}$ of these LAEs, we compiled a catalog of 800 HI absorption components. Our analysis shows that HI absorption is enhanced near the LAEs compared to the IGM. However, no trend is found between the column densities of HI absorbers and their impact parameters from the LAEs (spanning $\approx54$ to 260 pkpc). Additionally, all galaxies associated with Lyman-limit systems have impact parameters $>50$ pkpc from the quasar sightlines, suggesting that true absorber-hosts may be too faint to detect. The LAEs show an overall HI covering fraction (fc(HI)) of $\approx88\%$ for a threshold logN(HI)$=15$. Notably, at the same threshold, the pairs/group LAEs exhibit a $100\%$ HI covering fraction out to $\approx 250$ pkpc. In contrast, isolated LAEs consistently show a lower fc(HI) of $\approx80\%$. This environmental influence on fc(HI) is also evident up to $\approx 300$ km.$s^{-1}$ in differential bins of line-of-sight velocity. We find an anti-correlation between fc(HI) and the rest-frame lya-emission equivalent width (ew). Based on the lya-shell model, this could imply that gas-rich galaxies tend to reside in gas-rich environments or that the higher EW LAEs are more efficient at ionizing their surrounding medium.

astro-ph.GA↗

arXiv2025

MUSEQuBES: Unveiling Cosmic Web Filaments at $z\approx3.6$ through Dual Absorption and Emission Line Analysis

According to modern cosmological models, galaxies are embedded within cosmic filaments, which supply a continuous flow of pristine gas, fueling star formation and driving their evolution. However, due to their low density, the direct detection of diffuse gas in cosmic filaments remains elusive. Here, we report the discovery of an extremely metal-poor ($[ X/H] \approx -3.7$), low-density ($\log_{10} n_{\rm H}/{\rm cm^{-3}} \approx -4$, corresponding to an overdensity of $\approx 5$) partial Lyman limit system (pLLS) at $z\approx3.577$ along the quasar sightline Q1317--0507, probing cosmic filaments. Additionally, two other low-metallicity (\met$\lesssim -2$) absorption systems are detected at similar redshifts, one of which is also a pLLS. VLT/MUSE observations reveal a significant overdensity of \lya\ emitters (LAEs) associated with these absorbers. The spatial distribution of the LAEs strongly suggests the presence of an underlying filamentary structure. This is further supported by the detection of a large \lya\ emitting nebula with a surface brightness of $\geq 10^{-19}~\rm erg~cm^{-2}~s^{-1}~arcsec^{-2}$, with a maximum projected linear size of $\approx 260$~pkpc extending along the LAEs. This is the first detection of giant \lya\ emission tracing cosmic filaments, linked to normal galaxies and likely powered by in-situ recombination.

astro-ph.GA↗

arXiv2023

MUSEQuBES: The relation between Ly$α$ emitters and C IV absorbers at $z \approx 3.3$

We present a detailed study of the column density and covering fraction profiles of C IV absorption around 86 redshift $z \approx 3.3$ Ly$α$ emitters (LAEs) detected in 8 Multi-Unit Spectroscopic Explorer (MUSE) fields of $1'\times 1'$ centered on 8 bright background quasars as part of the MUSEQuBES survey. Using Voigt profile fitting of all the C IV absorbers detected along these 8 sightlines, we generated a ``blind'' absorbers' catalog consisting of 489 C IV absorption components. We cross-matched this blind C IV catalog with the MUSE-detected LAE catalog and found a significant enhancement of C IV components within $\approx \pm$400 $\rm km\, s^{-1}$ of the systemic redshifts of the LAEs. Neither the C IV column density ($N$) nor the Doppler parameter ($b$) of individual C IV components shows any significant anti-correlation with impact parameter ($ρ$) of the LAEs in the 68 percentile range of $90\leq ρ\leq 230$ physical kpc (pkpc). We find a covering fraction of $\approx 60\%$ for a threshold $N$(C IV) of $10^{12.5}\, \rm \rm cm^{-2}$, which is roughly twice as high as in random regions. The C IV covering fraction remains constant at $\approx50\%$ for impact parameters in the range 150--250~pkpc ($\approx 3-6 R_{200}$). Using the covering fraction profile, we constrained the LAE--C IV absorber two-point correlation function, and obtained $r_0 = 3.4$ comoving Mpc (cMpc) and $γ= 1.2$ for a threshold $N$(C IV) of $10^{13.0}\, \rm cm^{-2}$. The C IV covering fraction is found to be enhanced for the LAEs that are part of a ``pair/group'' compared to the isolated ones.

astro-ph.GA↗