SDSS-IV MaNGA: global and local stellar population properties of elliptical galaxies and their assembly histories. (arXiv:2001.05506v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lacerna_I/0/1/0/all/0/1">I. Lacerna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ibarra_Medel_H/0/1/0/all/0/1">H. Ibarra-Medel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Avila_Reese_V/0/1/0/all/0/1">V. Avila-Reese</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_Toledo_H/0/1/0/all/0/1">H. M. Hernández-Toledo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vazquez_Mata_J/0/1/0/all/0/1">J. A. Vázquez-Mata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_S/0/1/0/all/0/1">S. F. Sánchez</a>
We study the spatially resolved properties of 333 elliptical galaxies with
the MaNGA/SDSS-IV survey. The aim is to understand the fundamental processes of
formation and quenching of elliptical galaxies. We used the DESI Legacy Imaging
Surveys for accurate morphological classification. Based on integrated
spectroscopic properties and colors, we classified galaxies into classical “red
and dead”, recently quenched, and blue star-forming ellipticals (CLEs, RQEs,
and BSFs corresponding to 75%, 10%, and 4% of the sample, respectively). We
inferred their stellar age and stellar metallicity gradients out to 1.5
effective radius, and reconstructed their global and radial histories of mass
growth and star formation. We find the mass- and light-weighted age gradients
of CLEs are nearly flat or mildly negative, with small differences between both
ages. The respective metallicity gradients are negative, being flatter as less
massive are the CLEs. The more massive CLEs assembled earlier and quenched
faster than the less massive ones. The CLEs show a weak inside-out growth and a
clear inside-out quenching. At masses < $10^{11}$ $M_{bigodot}$, the age and
$Z$ gradients of the RQEs and BSFs are flatter than those of the CLEs but with
larger scatters. They show very weak inside-out growth and quenching, being the
quenching slow and even not completed at $zsim$ 0 for the BSFs. Instead, the
massive RQEs show an outside-in quenching, and positive gradients in the
light-weighted age and stellar metallicities. Our results are consistent with a
scenario where the inner parts of CLEs formed by an early and coeval
dissipative collapse with a consequent burst of star formation and further
quenching, whereas the outer parts continued their assembly likely by dry
mergers. We also discuss some evolutionary scenarios for the RQE and BSF
galaxies that would agree with their generic results presented here.
We study the spatially resolved properties of 333 elliptical galaxies with
the MaNGA/SDSS-IV survey. The aim is to understand the fundamental processes of
formation and quenching of elliptical galaxies. We used the DESI Legacy Imaging
Surveys for accurate morphological classification. Based on integrated
spectroscopic properties and colors, we classified galaxies into classical “red
and dead”, recently quenched, and blue star-forming ellipticals (CLEs, RQEs,
and BSFs corresponding to 75%, 10%, and 4% of the sample, respectively). We
inferred their stellar age and stellar metallicity gradients out to 1.5
effective radius, and reconstructed their global and radial histories of mass
growth and star formation. We find the mass- and light-weighted age gradients
of CLEs are nearly flat or mildly negative, with small differences between both
ages. The respective metallicity gradients are negative, being flatter as less
massive are the CLEs. The more massive CLEs assembled earlier and quenched
faster than the less massive ones. The CLEs show a weak inside-out growth and a
clear inside-out quenching. At masses < $10^{11}$ $M_{bigodot}$, the age and
$Z$ gradients of the RQEs and BSFs are flatter than those of the CLEs but with
larger scatters. They show very weak inside-out growth and quenching, being the
quenching slow and even not completed at $zsim$ 0 for the BSFs. Instead, the
massive RQEs show an outside-in quenching, and positive gradients in the
light-weighted age and stellar metallicities. Our results are consistent with a
scenario where the inner parts of CLEs formed by an early and coeval
dissipative collapse with a consequent burst of star formation and further
quenching, whereas the outer parts continued their assembly likely by dry
mergers. We also discuss some evolutionary scenarios for the RQE and BSF
galaxies that would agree with their generic results presented here.
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