Late Bloomer Galaxies: Growing Up in Cosmic Autumn

Abstract

Late bloomers are massive ($M_{\ast }>10^{10}{M}_{\odot }$) galaxies at $z<1$ that formed the majority of their stars within $\sim$2 Gyr of the epoch of observation. Our improved methodology for deriving star formation histories (SFHs) of galaxies at redshifts $0.45<z<0.75$ from the Carnegie-Spitzer-IMACS Survey includes confidence intervals that robustly distinguish late bloomers from "old" galaxies. We use simulated SFHs to test for "false positives" and contamination from old galaxies to demonstrate that the late bloomer population is not an artifact of our template modeling technique. We show that late bloomers account for $\sim$20% of $z\sim 0.6$ galaxies with masses of the modern Milky Way, with a moderate dependence on mass. We take advantage of a 1% overlap of our sample with HST (CANDELS) imaging to construct a "gold standard" catalog of 74 galaxies with high-confidence SFHs, SEDs, basic data, and HST images to facilitate comparison with future studies by others. This small subset suggests that galaxies with both old and young SFHs cover the full range of morphology and environment (excluding rich groups or clusters), albeit with a mild but suggestive correlation with local environment. We begin the investigation of whether late bloomers of sufficient mass and frequency are produced in current-generation $\Lambda$CDM-based semi-analytic models of galaxy formation. In terms of halo growth, we find a late-assembling halo fraction within a factor-of-two of our late bloomer fraction. However, sufficiently delaying star formation in such halos may be a challenge for the baryon component of such models.

27 pages, 16 figures, 4 tables, 1 ancillary data file (.xml input file to generate GALACTICUS SAM results). Accepted to ApJ. Revises previous (submitted) version; results unchanged

References in corpus (19)

• Cosmic Star Formation History
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• Constraining the Low-Mass Slope of the Star Formation Sequence at 0.5<z<2.5
• PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function From z=0-1
• Charting the evolution of the ages and metallicities of massive galaxies since z=0.7
• The evolution of star formation histories of quiescent galaxies
• Galaxy And Mass Assembly (GAMA): The mechanisms for quiescent galaxy formation at $z<1$
• MultiDark-Galaxies: data release and first results
• SFHs OF $Z\sim 1$ Galaxies in LEGA-C
• Matching the Evolution of the Stellar Mass Function Using Log-normal Star Formation Histories
• Decoding the Star-Forming Main Sequence or: How I Learned to Stop Worrying and Love the Central Limit Theorem
• Demonstrating Diversity in Star Formation Histories with the CSI Survey
• On the Origin and Evolution of the Galaxy Stellar Mass Function
• The Grism Lens-Amplified Survey from Space (GLASS). XII. Spatially Resolved Galaxy Star Formation Histories and True Evolutionary Paths at z > 1
• The resolved star formation history of M51a through successive Bayesian marginalization

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• Fast, Slow, Early, Late: Quenching Massive Galaxies at z~0.8
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• The star formation histories of z~1 post-starburst galaxies
• Massive Dead Galaxies at z~2 with HST Grism Spectroscopy I. Star Formation Histories and Metallicity Enrichment
• Introducing piXedfit -- a Spectral Energy Distribution Fitting Code Designed for Resolved Sources
• The GOGREEN survey: Post-infall environmental quenching fails to predict the observed age difference between quiescent field and cluster galaxies at z>1
• Early Results From GLASS-JWST. XVII: Building the First Galaxies -- Chapter 1. Star Formation Histories at 5<z < 7
• REQUIEM-2D: Spatially Resolved Stellar Populations from HST 2D Grism Spectroscopy
• The frequency of very young galaxies in the local Universe: II. The view from SDSS spectra
• DESI Survey Validation Spectra Reveal an Increasing Fraction of Recently Quenched Galaxies at $z\sim 1$
• Constraints on Fluctuating Star Formation Rates for Intermediate-mass Galaxies with H$\alpha$ and UV Luminosities
• Gravity and the Nonlinear Growth of Structure in the Carnegie-Spitzer-IMACS Redshift Survey
• The Grism Lens-Amplified Survey from Space (GLASS). XIII. G800L optical spectra from the parallel fields
• The properties and environment of very young galaxies in the local Universe