The star formation timescale of elliptical galaxies Fitting [Mg/Fe] and total metallicity simultaneously

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10406205" target="_blank" >RIV/00216208:11320/19:10406205 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Ynft1m5RfM" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Ynft1m5RfM</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201936636" target="_blank" >10.1051/0004-6361/201936636</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The star formation timescale of elliptical galaxies Fitting [Mg/Fe] and total metallicity simultaneously

Popis výsledku v původním jazyce

The alpha element to iron peak element ratio, for example [Mg/Fe], is a commonly applied indicator of the galaxy star formation timescale (SFT) since the two groups of elements are mainly produced by different types of supernovae that explode over different timescales. However, it is insufficient to consider only [Mg/Fe] when estimating the SFT. The [Mg/Fe] yield of a stellar population depends on its metallicity. Therefore, it is possible for galaxies with different SFTs and at the same time different total metallicity to have the same [Mg/Fe]. This effect has not been properly taken into consideration in previous studies. In this study, we assume the galaxy-wide stellar initial mass function (gwIMF) to be canonical and invariant. We demonstrate that our computation code reproduces the SFT estimations of previous studies, where only the [Mg/Fe] observational constraint is applied. We then demonstrate that once both metallicity and [Mg/Fe] observations are considered, a more severe &quot;downsizing relation&quot; is required. This means that either low-mass ellipticals have longer SFTs (&gt; 4 Gyr for galaxies with mass below 10(10) M-circle dot) or massive ellipticals have shorter SFTs (approximate to 200 Myr for galaxies more massive than 10(11) M-circle dot) than previously thought. This modification increases the difficulty in reconciling such SFTs with other observational constraints. We show that applying different stellar yield modifications does not relieve this formation timescale problem. The quite unrealistically short SFT required by [Mg/Fe] and total metallicity would be prolonged if a variable stellar gwIMF were assumed. Since a systematically varying gwIMF has been suggested by various observations this could present a natural solution to this problem.

Název v anglickém jazyce

The star formation timescale of elliptical galaxies Fitting [Mg/Fe] and total metallicity simultaneously

Popis výsledku anglicky

The alpha element to iron peak element ratio, for example [Mg/Fe], is a commonly applied indicator of the galaxy star formation timescale (SFT) since the two groups of elements are mainly produced by different types of supernovae that explode over different timescales. However, it is insufficient to consider only [Mg/Fe] when estimating the SFT. The [Mg/Fe] yield of a stellar population depends on its metallicity. Therefore, it is possible for galaxies with different SFTs and at the same time different total metallicity to have the same [Mg/Fe]. This effect has not been properly taken into consideration in previous studies. In this study, we assume the galaxy-wide stellar initial mass function (gwIMF) to be canonical and invariant. We demonstrate that our computation code reproduces the SFT estimations of previous studies, where only the [Mg/Fe] observational constraint is applied. We then demonstrate that once both metallicity and [Mg/Fe] observations are considered, a more severe &quot;downsizing relation&quot; is required. This means that either low-mass ellipticals have longer SFTs (&gt; 4 Gyr for galaxies with mass below 10(10) M-circle dot) or massive ellipticals have shorter SFTs (approximate to 200 Myr for galaxies more massive than 10(11) M-circle dot) than previously thought. This modification increases the difficulty in reconciling such SFTs with other observational constraints. We show that applying different stellar yield modifications does not relieve this formation timescale problem. The quite unrealistically short SFT required by [Mg/Fe] and total metallicity would be prolonged if a variable stellar gwIMF were assumed. Since a systematically varying gwIMF has been suggested by various observations this could present a natural solution to this problem.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

—

Svazek periodika

632

Číslo periodika v rámci svazku

prosinec

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

9

Strana od-do

A110

Kód UT WoS článku

000502330300004

EID výsledku v databázi Scopus

—