Comparative Bayesian SED Fitting of PEARLSDG

TL;DR

This study revises the distance to PEARLSDG from 30 Mpc to approximately 124 Mpc, using spectroscopy and Bayesian SED fitting, revealing its properties align with typical galaxy relations and environmental quenching.

Contribution

It provides a revised distance measurement and detailed Bayesian SED analysis of PEARLSDG, clarifying its metallicity, stellar mass, and star-formation history in a group environment.

Findings

Distance to PEARLSDG is revised to ~124 Mpc from 30 Mpc.

Metallicity places PEARLSDG on the standard mass--metallicity relation.

Star-formation history suggests environmental quenching.

Abstract

The initial distance to PEARLSDG estimated from the Tip of the Red Giant Branch suggested it was an exotic isolated quiescent dwarf galaxy. We combine recent and archival Hectospec spectroscopy to place it at $z = 0.02843 \pm 0.00012$ ($D \approx 124$\,Mpc) within a galaxy group, revising the distance from 30\,Mpc to $\sim$124\,Mpc. We then carry out {\sc Prospector} SED fitting using parametric and non-parametric star-formation histories sampled with \texttt{dynesty}, \texttt{nautilus}, and \texttt{emcee}, recovering metallicity $\log(Z/Z_\odot) = -0.44^{+0.35}_{-0.06}$, stellar mass $\log_{10}(M_*/M_\odot) = 9.25^{+0.02}_{-3.73}$, and dust attenuation $\hat{\tau}_V = 0.67^{+0.02}_{-0.05}$. The updated metallicity places PEARLSDG squarely on the standard mass--metallicity relation, resolving its former outlier status, with its quenched star-formation history consistent with environmental quenching in a group setting.