Structure and Kinematics of Star-forming Elliptical Galaxies in SDSS-MaNGA

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Auteurs principaux: Biswas, Pralay, Wadadekar, Yogesh
Format: Preprint
Publié: 2024
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author Biswas, Pralay
Wadadekar, Yogesh
author_facet Biswas, Pralay
Wadadekar, Yogesh
contents Using 'spatially' resolved spectroscopy, we investigated the characteristics and different modes of formation of stars in elliptical galaxies. We identified an unusual population of 59 star-forming elliptical (SF-E) galaxies in SDSS-MaNGA, our primary sample. To identify these rare star-forming ellipticals, we combined GSWLC-A2 containing outputs of stellar population synthesis models with morphological results from the deep-learning catalog and resolved and integrated properties from the MaNGA Pipe3D value-added catalog. We have also constructed two control samples of star-forming spirals (SF-Sps; 2419 galaxies) and quenched ellipticals (Q-Es; 684 galaxies) to compare with our primary sample of SF-Es. H$α$ emission line flux of SF-Es is similar to spiral galaxies. The D4000 spectral index indicates that SF-Es have a mixture of old and young stellar populations. Mass-weighted stellar age and metallicity for the SF-Es are lower than the Q-Es and 67\% of stellar- and gas- velocity maps of the primary sample show signs of kinematic disturbance. All of these indicate that SF-Es have acquired metal-poor gas through recent mergers or interactions with other galaxies and are forming a new generation of stars. Further, we subdivide our primary sample of SF-Es into four classes based on their bulge to total luminosity ratio $(B/T)$ and spin parameter $λ_{re}$. These four classes have their distinct evolutionary history and modes of formation. Based on these results, we suggest that the Hubble diagram does not accurately capture galaxy evolution processes, and we need a revised morphology diagram like the comb morphology diagram to get a complete picture of the galaxy evolution processes.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04166
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Structure and Kinematics of Star-forming Elliptical Galaxies in SDSS-MaNGA
Biswas, Pralay
Wadadekar, Yogesh
Astrophysics of Galaxies
Using 'spatially' resolved spectroscopy, we investigated the characteristics and different modes of formation of stars in elliptical galaxies. We identified an unusual population of 59 star-forming elliptical (SF-E) galaxies in SDSS-MaNGA, our primary sample. To identify these rare star-forming ellipticals, we combined GSWLC-A2 containing outputs of stellar population synthesis models with morphological results from the deep-learning catalog and resolved and integrated properties from the MaNGA Pipe3D value-added catalog. We have also constructed two control samples of star-forming spirals (SF-Sps; 2419 galaxies) and quenched ellipticals (Q-Es; 684 galaxies) to compare with our primary sample of SF-Es. H$α$ emission line flux of SF-Es is similar to spiral galaxies. The D4000 spectral index indicates that SF-Es have a mixture of old and young stellar populations. Mass-weighted stellar age and metallicity for the SF-Es are lower than the Q-Es and 67\% of stellar- and gas- velocity maps of the primary sample show signs of kinematic disturbance. All of these indicate that SF-Es have acquired metal-poor gas through recent mergers or interactions with other galaxies and are forming a new generation of stars. Further, we subdivide our primary sample of SF-Es into four classes based on their bulge to total luminosity ratio $(B/T)$ and spin parameter $λ_{re}$. These four classes have their distinct evolutionary history and modes of formation. Based on these results, we suggest that the Hubble diagram does not accurately capture galaxy evolution processes, and we need a revised morphology diagram like the comb morphology diagram to get a complete picture of the galaxy evolution processes.
title Structure and Kinematics of Star-forming Elliptical Galaxies in SDSS-MaNGA
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2405.04166