Galaxy Rest-Frame UV Colors at z ~ 2-4 with HST UVCANDELS

We present an analysis of rest-frame UV colors of 17,243 galaxies at $z\sim2-4$ in the HST UVCANDELS fields: GOODS-N, GOODS-S, COSMOS, and EGS. Here, we study the rest-frame UV spectral slope, $\beta$, measured via model spectra obtained via spectral energy distribution (SED) fitting, $\beta_{SED}$, and explore its correlation with various galaxy parameters (photometric redshift, UV magnitude, stellar mass, dust attenuation, star formation rate [SFR], and specific SFR) obtained via SED fitting with Dense Basis. We also obtain measurements for $\beta$ via photometric power-law fitting and compare them to our SED-fit-based results, finding good agreement on average. While we find little evolution in $\beta$ with redshift from $z=2-4$ for the full population, there are clear correlations between $\beta$ (and related parameters) when binned by stellar mass. For this sample, lower stellar mass galaxies (log[$M_*$] = 7.5-8.5 $M_\odot$) are typically bluer ($\beta_{SED}=-2.0\pm 0.2$ / $\beta_{PL} = -2.1\pm0.4$), fainter ($MUV = -17.8^{+0.7}_{-0.6}$) less dusty ($A{v}=0.4\pm0.1$ mag), exhibit lower rates of star formation (log[SFR]=$0.1\pm0.2 M_\odot/$ yr) and higher specific star formation rates (log[sSFR]=$-8.2\pm0.2 \ \mathrm{yr}^{-1}$) than their high-mass counterparts. Higher-mass galaxies (log[$M_*$] $=10.0-12.0 \ M_\odot$) are on average redder ($\beta_{SED}=-0.9^{+0.8}_{-0.5}$ / $\beta_{PL}=-1.0^{+0.8}_{-0.5}$), brighter ($MUV=-19.6^{+1.0}_{-1.2}$), dustier ($Av = 0.9^{+0.5}_{-0.4}$ mag), have higher SFRs (log[SFR]=$1.2^{+0.6}_{-1.1} M_\odot$ yr), and lower sSFRs (log[sSFR]=$-9.1^{+0.5}_{-1.1} {yr}^{-1}$). This study's substantial sample size provides a benchmark for demonstrating that the rest-frame UV spectral slope correlates with stellar mass-dependent galaxy characteristics at $z\sim2-4$, a relationship less discernible with smaller datasets typically available at higher redshifts.