# Delving deep: a population of extremely dusty dwarfs observed by JWST

## TL;DR

This study uses JWST NIRCam data to identify extremely dusty, low-mass galaxies at redshifts below 2, revealing unexpectedly high dust extinction levels in these faint objects.

## Contribution

It introduces a new selection method for dusty galaxies using JWST data, uncovering low-mass, highly obscured galaxies at z<2 with unexpectedly high dust extinction.

## Key findings

- Most dusty galaxies are at z<2 with median stellar mass of 10^7.3 M_sun.
- No strong dusty galaxy candidates found at z>6.5.
- Galaxies exhibit median dust extinction of Av=4.9 mag.

## Abstract

We take advantage of the NIRCam photometric observations available as part of the Cosmic Evolution Early Release Science survey (CEERS) to identify and analyse very red sources in an effort to discover very dusty star forming galaxies. We select red galaxies as objects with a S/N>3 at 4.4 $\mu$m and a S/N<2 in all JWST and HST filters at $\lambda\leq2\mu$m, which corresponds to [F200W]-[F444W]>1.2 considering CEERS depths. This selection is ideal to identify very dusty (Av>1 mag) galaxies with stellar masses between $10^6$ to $10^{10}\, \rm M_{\odot}$ at z<5, more massive dusty galaxies at z=5-18 and galaxies at z>18 due to the Lyman absorption, independently of their dust extinction. Our sample of F200W-dropouts contains no strong candidates at z>6.5, instead it consists almost completely (~81%) of z<2 low-mass galaxies, with a median stellar mass of $10^{7.3} \rm M_{\odot}$. These galaxies show an exceptional dust extinction with median value of Av=4.9 mag, completely unexpected given their low stellar mass. The remaining galaxies, which are at z<6.5, show similar large dust extinction (Av>1), but they are generally more massive $>10^{7.5}\rm M_{\odot}$.