Tracing Galaxy Evolution in infalling galaxies of Abell 496: From Starburst to Quenching

TL;DR

This study investigates how infalling galaxies in Abell 496 evolve from starburst to quenching by analyzing UV and HI data, revealing an evolutionary sequence influenced by environmental mechanisms like ram pressure stripping and tidal interactions.

Contribution

It introduces a detailed evolutionary sequence for infalling galaxies in a cluster, combining UV and HI observations to identify stages from starburst to quenching.

Findings

FUV-detected galaxies have higher specific star formation rates.

High-mass FUV galaxies without neighbors suggest ram pressure stripping effects.

Low-mass FUV galaxies with companions indicate tidal interactions influence evolution.

Abstract

During the fall of late-type galaxies into clusters, they can experiment a variety of evolutionary mechanisms according their local environment. Consequently, studying the UV emission and the cold gas of late-type galaxies provide key insights in the evolution of short-lived starburst and galaxy quenching. In this work, we conduted a study of two 28' fields observed with UVIT-AstroSat in the central region of the Abell cluster A496 ($z=0.033$), including HI, data from NRAO VLA. We reported 22 cluster members detected in FUV; all of them are detected in HI, or have upper limits for the HI-mass. We find our FUV detected galaxies generally have higher specific star formation rates than other star forming galaxies. Most of the FUV galaxies with masses above 10$^9 \mathrm{M}_{\odot}$,and showing high sSFR have no close neighbors, pointing at RPS as the dominant mechanism affecting them. In contrast, most of the low-mass FUV objects present at least one companion, suggesting that tidal interactions also play an important role in the triggering of infalling galaxies. Combining the FUV-SFR with the HI properties of the observed galaxies in A496 we identify an evolutionary sequence consisting of five stages: (1) Pre-triggering, (2) Initial SF-triggering, (3) Peak of star-formation, (4) SF-fading, and (5) SF-quenching. During this path, normal gas-rich objects reach a gas-deficiency phase with SFR well below the main sequence. This process, prior to becoming a full passive galaxy, can be accomplished within a few 10$^{8}$ yr.