Poster Presentation
Evidence of environmental effects: investigating star formation and quenching in perturbed galaxies of nearby clusters
Presenter: Martha Margarita Lopez gutierrez (Korea Institute for Advanced Study (KIAS))
We investigate the influence of the local environment on the morphological transformation of spiral galaxies in three nearby Abell clusters (A85, A496, and A2670) at redshifts z < 0.08. This study utilizes multiwavelength observations, including VLA HI (21 cm) radio data, optical imaging from CFHT, and ultraviolet imaging from AstroSat-UVIT. We present further evidence of environmental effects, including significant fractions (0.10–0.33) of HI-abnormal objects and red (passive) spirals, indicative of ongoing quenching processes. Analyzing the global distribution of HI-normal and HI-disturbed spirals across three combined clusters, we confirm a correlation where disturbed objects are preferentially located at smaller projected radii. To explore the SF triggering and quenching, we conducted FUV study on a sample of disturbed spiral galaxies in the nearby cluster A496 (z = 0.033). This system shows an anti-correlation between the cluster-centric distance and HI-deficiency. We analyze the FUV star formation rates (SFR), HI properties, and the disruptions observed in HI and other wavelengths. We propose an evolutionary sequence consisting of five stages, going from a normal star forming late-type, to an HI-deficient object with fading SFR and running into the quenching phase. We examine the impact of ram-pressure stripping (RPS) as well as gravitational effects exerted by possible companions. We have found that FUV galaxies with masses above 109 M⊙ are dominated by RPS while lower-mass counterparts present close companion. Our multiwavelength analysis examines morphology, kinematics, stellar populations, and HI gas in infalling late-type galaxies, revealing mechanisms behind their star formation and quenching.
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