Two rest-frame wavelength measurements of galaxy sizes at $z<1$: the evolutionary effects of emerging bulges and quenched newcomers

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Main Authors: George, Angelo, Damjanov, Ivana, Sawicki, Marcin, Arnouts, Stéphane, Desprez, Guillaume, Gwyn, Stephen, Picouet, Vincent, Birrer, Simon, Silverman, John
Format: Preprint
Published: 2024
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author George, Angelo
Damjanov, Ivana
Sawicki, Marcin
Arnouts, Stéphane
Desprez, Guillaume
Gwyn, Stephen
Picouet, Vincent
Birrer, Simon
Silverman, John
author_facet George, Angelo
Damjanov, Ivana
Sawicki, Marcin
Arnouts, Stéphane
Desprez, Guillaume
Gwyn, Stephen
Picouet, Vincent
Birrer, Simon
Silverman, John
contents We analyze the size evolution of $16000$ star-forming galaxies (SFGs) and $5000$ quiescent galaxies (QGs) with mass $M_*>10^{9.5}M_\odot$ at $0.1<z<0.9$ from the COSMOS field using deep CLAUDS+HSC imaging in two rest-frame wavelengths, $3000$Å (UV light) and $5000$Å (visible light). With half-light radius ($R_e$) as proxy for size, SFGs at characteristic mass $M_0 = 5\times10^{10}M_\odot$ grow by $20\%$ ($30\%$) in UV (visible) light since $z\sim1$ and the strength of their size evolution increases with stellar mass. After accounting for mass growth due to star formation, we estimate that SFGs grow by $75\%$ in all stellar mass bins and in both rest-frame wavelengths. Redder SFGs are more massive, smaller and more concentrated than bluer SFGs and the fraction of red SFGs increases with time. These results point to the emergence of bulges as the dominant mechanism for the average size growth of SFGs. We find two threshold values for the stellar mass density within central $1$kpc ($Σ_1$): all SFGs with $\logΣ_1 > 9$ are red and only QGs have $\logΣ_1>9.7$. The size of $M_*=M_0$ QGs grows by $50\%$ ($110\%$) in the UV (visible) light. Up to $\sim20\%$ of this increase in size of massive QGs is due to newcomers (recently quenched galaxies). However, newcomers cannot explain the observed pace in the size growth of QGs; that trend has to be dominated by processes affecting individual galaxies, such as minor mergers and accretion.
format Preprint
id arxiv_https___arxiv_org_abs_2401_06842
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Two rest-frame wavelength measurements of galaxy sizes at $z<1$: the evolutionary effects of emerging bulges and quenched newcomers
George, Angelo
Damjanov, Ivana
Sawicki, Marcin
Arnouts, Stéphane
Desprez, Guillaume
Gwyn, Stephen
Picouet, Vincent
Birrer, Simon
Silverman, John
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
We analyze the size evolution of $16000$ star-forming galaxies (SFGs) and $5000$ quiescent galaxies (QGs) with mass $M_*>10^{9.5}M_\odot$ at $0.1<z<0.9$ from the COSMOS field using deep CLAUDS+HSC imaging in two rest-frame wavelengths, $3000$Å (UV light) and $5000$Å (visible light). With half-light radius ($R_e$) as proxy for size, SFGs at characteristic mass $M_0 = 5\times10^{10}M_\odot$ grow by $20\%$ ($30\%$) in UV (visible) light since $z\sim1$ and the strength of their size evolution increases with stellar mass. After accounting for mass growth due to star formation, we estimate that SFGs grow by $75\%$ in all stellar mass bins and in both rest-frame wavelengths. Redder SFGs are more massive, smaller and more concentrated than bluer SFGs and the fraction of red SFGs increases with time. These results point to the emergence of bulges as the dominant mechanism for the average size growth of SFGs. We find two threshold values for the stellar mass density within central $1$kpc ($Σ_1$): all SFGs with $\logΣ_1 > 9$ are red and only QGs have $\logΣ_1>9.7$. The size of $M_*=M_0$ QGs grows by $50\%$ ($110\%$) in the UV (visible) light. Up to $\sim20\%$ of this increase in size of massive QGs is due to newcomers (recently quenched galaxies). However, newcomers cannot explain the observed pace in the size growth of QGs; that trend has to be dominated by processes affecting individual galaxies, such as minor mergers and accretion.
title Two rest-frame wavelength measurements of galaxy sizes at $z<1$: the evolutionary effects of emerging bulges and quenched newcomers
topic Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2401.06842