Deciphering the properties of UV upturn galaxies in the Virgo cluster

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Auteurs principaux: Akhil, Krishna R., Kartha, Sreeja S, Kizhuprakkat, Namitha, Ujjwal, K., P, Niranjana
Format: Preprint
Publié: 2024
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author Akhil, Krishna R.
Kartha, Sreeja S
Kizhuprakkat, Namitha
Ujjwal, K.
P, Niranjana
author_facet Akhil, Krishna R.
Kartha, Sreeja S
Kizhuprakkat, Namitha
Ujjwal, K.
P, Niranjana
contents The UV upturn refers to the increase in UV flux at wavelengths shorter than 3000 Å observed in quiescent early-type galaxies (ETGs), which still remains a puzzle. In this study, we aim to identify ETGs showing the UV upturn phenomenon within the Virgo galaxy cluster. We utilized a color-color diagram to identify all potential possible UV upturn galaxies. The Spectral Energy Distributions (SED) of these galaxies were then analyzed using the CIGALE software; we confirmed the presence of UV upturn in galaxies within the Virgo cluster. We found that the SED fitting method is the best tool to visualize and confirm the UV upturn phenomenon in ETGs. Our findings reveal that the population distributions regarding stellar mass and star formation rate properties are similar between UV upturn and red sequence galaxies. We suggest that the UV contribution originates from old stellar populations and can be modeled effectively without a burst model. Moreover, by estimating the temperature of the stellar population responsible for the UV emission, we determined it to be 13,000 K to 18,000 K. These temperature estimates support the notion that the UV upturn likely arises from the contribution of low mass evolved stellar populations (extreme horizontal branch stars). Furthermore, the Mg2 index, a metallicity indicator, in the confirmed upturn galaxies shows higher strength and follows a similar trend to previous studies. This study sheds light on the nature of UV upturn galaxies within the Virgo cluster and provides evidence that low-mass evolved stellar populations are the possible mechanisms driving the UV upturn phenomenon.
format Preprint
id arxiv_https___arxiv_org_abs_2410_17328
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Deciphering the properties of UV upturn galaxies in the Virgo cluster
Akhil, Krishna R.
Kartha, Sreeja S
Kizhuprakkat, Namitha
Ujjwal, K.
P, Niranjana
Astrophysics of Galaxies
The UV upturn refers to the increase in UV flux at wavelengths shorter than 3000 Å observed in quiescent early-type galaxies (ETGs), which still remains a puzzle. In this study, we aim to identify ETGs showing the UV upturn phenomenon within the Virgo galaxy cluster. We utilized a color-color diagram to identify all potential possible UV upturn galaxies. The Spectral Energy Distributions (SED) of these galaxies were then analyzed using the CIGALE software; we confirmed the presence of UV upturn in galaxies within the Virgo cluster. We found that the SED fitting method is the best tool to visualize and confirm the UV upturn phenomenon in ETGs. Our findings reveal that the population distributions regarding stellar mass and star formation rate properties are similar between UV upturn and red sequence galaxies. We suggest that the UV contribution originates from old stellar populations and can be modeled effectively without a burst model. Moreover, by estimating the temperature of the stellar population responsible for the UV emission, we determined it to be 13,000 K to 18,000 K. These temperature estimates support the notion that the UV upturn likely arises from the contribution of low mass evolved stellar populations (extreme horizontal branch stars). Furthermore, the Mg2 index, a metallicity indicator, in the confirmed upturn galaxies shows higher strength and follows a similar trend to previous studies. This study sheds light on the nature of UV upturn galaxies within the Virgo cluster and provides evidence that low-mass evolved stellar populations are the possible mechanisms driving the UV upturn phenomenon.
title Deciphering the properties of UV upturn galaxies in the Virgo cluster
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2410.17328