INSPIRE: INvestigating Stellar Population In RElics VI -- The low-mass end slope of the stellar Initial Mass Function and chemical composition

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Hauptverfasser: Maksymowicz-Maciata, Michalina, Spiniello, Chiara, Martín-Navarro, Ignacio, Ferré-Mateu, Anna, Bevacqua, Davide, Cappellari, Michele, D'Ago, Giuseppe, Tortora, Crescenzo, Arnaboldi, Magda, Hartke, Johanna, Saracco, Paolo, Scognamiglio, Diana
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Veröffentlicht: 2024
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author Maksymowicz-Maciata, Michalina
Spiniello, Chiara
Martín-Navarro, Ignacio
Ferré-Mateu, Anna
Bevacqua, Davide
Cappellari, Michele
D'Ago, Giuseppe
Tortora, Crescenzo
Arnaboldi, Magda
Hartke, Johanna
Saracco, Paolo
Scognamiglio, Diana
author_facet Maksymowicz-Maciata, Michalina
Spiniello, Chiara
Martín-Navarro, Ignacio
Ferré-Mateu, Anna
Bevacqua, Davide
Cappellari, Michele
D'Ago, Giuseppe
Tortora, Crescenzo
Arnaboldi, Magda
Hartke, Johanna
Saracco, Paolo
Scognamiglio, Diana
contents The INSPIRE project has built the largest sample of ultra-compact massive galaxies (UCMGs) at 0.1<z<0.4 and obtained their star formation histories (SFHs). Due to their preserved very old stellar populations, relics are the perfect systems to constrain the earliest epochs of mass assembly in the Universe and the formation of massive early-type galaxies. The goal of this work is to investigate whether a correlation exists between the degree of relicness (DoR), quantifying the fraction of stellar mass formed at z>2, and the other stellar population parameters.We use the Full-Index-Fitting method to fit the INSPIRE spectra to single stellar population (SSP) models. This allows us to measure, for the first time, the low-mass end slope of the IMF, as well as stellar metallicity [M/H], [Mg/Fe], [Ti/Fe] and [Na/Fe] ratios, and study correlations between them and the DoR. Similarly to normal-sized galaxies, UCMGs with larger stellar masses have overall higher metallicities. We found a correlation between the low-mass end of the IMF slope and the DoR, that, however, breaks down for systems with a more extended SFH. An even stronger dependency is found between the IMF and the fraction of mass formed at high-z. At equal velocity dispersion and metallicity, galaxies with a higher DoR have a dwarf-richer IMF than that of low-DoR counterparts. This might indicate that the cosmic epoch and formation mechanisms influence the fragmentation of the star formation cloud and hence might be the explanation for IMF variations detected in massive ETGs.
format Preprint
id arxiv_https___arxiv_org_abs_2401_15769
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle INSPIRE: INvestigating Stellar Population In RElics VI -- The low-mass end slope of the stellar Initial Mass Function and chemical composition
Maksymowicz-Maciata, Michalina
Spiniello, Chiara
Martín-Navarro, Ignacio
Ferré-Mateu, Anna
Bevacqua, Davide
Cappellari, Michele
D'Ago, Giuseppe
Tortora, Crescenzo
Arnaboldi, Magda
Hartke, Johanna
Saracco, Paolo
Scognamiglio, Diana
Astrophysics of Galaxies
The INSPIRE project has built the largest sample of ultra-compact massive galaxies (UCMGs) at 0.1<z<0.4 and obtained their star formation histories (SFHs). Due to their preserved very old stellar populations, relics are the perfect systems to constrain the earliest epochs of mass assembly in the Universe and the formation of massive early-type galaxies. The goal of this work is to investigate whether a correlation exists between the degree of relicness (DoR), quantifying the fraction of stellar mass formed at z>2, and the other stellar population parameters.We use the Full-Index-Fitting method to fit the INSPIRE spectra to single stellar population (SSP) models. This allows us to measure, for the first time, the low-mass end slope of the IMF, as well as stellar metallicity [M/H], [Mg/Fe], [Ti/Fe] and [Na/Fe] ratios, and study correlations between them and the DoR. Similarly to normal-sized galaxies, UCMGs with larger stellar masses have overall higher metallicities. We found a correlation between the low-mass end of the IMF slope and the DoR, that, however, breaks down for systems with a more extended SFH. An even stronger dependency is found between the IMF and the fraction of mass formed at high-z. At equal velocity dispersion and metallicity, galaxies with a higher DoR have a dwarf-richer IMF than that of low-DoR counterparts. This might indicate that the cosmic epoch and formation mechanisms influence the fragmentation of the star formation cloud and hence might be the explanation for IMF variations detected in massive ETGs.
title INSPIRE: INvestigating Stellar Population In RElics VI -- The low-mass end slope of the stellar Initial Mass Function and chemical composition
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2401.15769