A mass threshold in the number density of passive galaxies at z$\sim$2

Abstract

The process that quenched star formation in galaxies at intermediate and high redshift is still the subject of considerable debate. One way to investigate this puzzling issue is to study the number density of quiescent galaxies at z~2, and its dependence on mass. Here we present the results of a new study based on very deep Ks-band imaging (with the HAWK-I instrument on the VLT) of two HST CANDELS fields (the UKIDSS Ultra-deep survey (UDS) field and GOODS-South). The new HAWK-I data (taken as part of the HUGS VLT Large Program) reach detection limits of Ks>26 (AB mag). We select a sample of passively-evolving galaxies in the redshift range 1.4<z<2.5. Thanks to the depth and large area coverage of our imaging, we have been able to extend the selection of quiescent galaxies a magnitude fainter than previous analyses. Through extensive simulations we demonstrate, for the first time, that the observed turn-over in the number of quiescent galaxies at K>22 is real. This has enabled us to establish unambiguously that the number counts of quiescent galaxies at z~2 flatten and slightly decline at magnitudes fainter than Ks~22(AB mag.). We show that this trend corresponds to a stellar mass threshold $M_{\ast }10^{10.8}{\mathrm{M}}_{\odot }$ below which the mechanism that halts the star formation in high-redshift galaxies seems to be inefficient. Finally we compare the observed pBzK number counts with those of quiescent galaxies extracted from four different semi-analytic models. We find that none of the models provides a statistically acceptable description of the number density of quiescent galaxies at these redshifts. We conclude that the mass function of quiescent galaxies as a function of redshift continues to present a key and demanding challenge for proposed models of galaxy formation and evolution.

arXiv commentAccepted for publication on Astronomy and Astrophysics

References in corpus (49)

• Stellar population synthesis at the resolution of 2003
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The broken hierarchy of galaxy formation
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics
• The Great Observatories Origins Deep Survey: Initial Results From Optical and Near-Infrared Imaging
• The hierarchical formation of the brightest cluster galaxies
• From dwarf spheroidals to cDs: Simulating the galaxy population in a LCDM cosmology
• Mass assembly in quiescent and star-forming galaxies since z=4 from UltraVISTA
• The formation history of elliptical galaxies
• The Evolution of the Stellar Mass Functions of Star-Forming and Quiescent Galaxies to z = 4 from the COSMOS/UltraVISTA Survey
• Halos and galaxies in the standard cosmological model: results from the Bolshoi simulation
• Passively Evolving Early-type Galaxies at 1.4<z<2.5 in the Hubble Ultra Deep Field
• A new photometric technique for the joint selection of star-forming and passive galaxies at 1.4<z<2.5
• CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field
• The Galaxy Mass Function up to z=4 in the GOODS-MUSIC sample: into the epoch of formation of massive galaxies
• Cosmic Variance and Its Effect on the Luminosity Function Determination in Deep High z Surveys
• The number density and mass density of star-forming and quiescent galaxies at 0.4 < z < 2.2
• The K20 survey. VI. The Distribution of the Stellar Masses in Galaxies up to z~2
• CANDELS Multiwavelength catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-Deep Survey Field
• The Subaru/XMM-Newton Deep Survey (SXDS) - II. Optical Imaging and Photometric Catalogs
• The high redshift galaxy population in hierarchical galaxy formation models
• The COSMOS-WIRCam near-infrared imaging survey: I: BzK selected passive and star forming galaxy candidates at z>1.4
• Galaxy Properties from the Ultra-violet to the Far-Infrared: Lambda-CDM models confront observations
• The build-up of the colour-magnitude relation in galaxy clusters since z~0.8
• A substantial population of massive quiescent galaxies at z~4 from ZFOURGE
• The Blast Wave Model for AGN Feedback: Effects on AGN Obscuration
• A Census of Optical and Near-Infrared Selected Star-Forming and Passively Evolving Galaxies at Redshift Z~2
• Properties of Galaxy Groups in the SDSS: II.- AGN Feedback and Star Formation Truncation
• Lightcone mock catalogues from semi-analytic models of galaxy formation - I. Construction and application to the BzK colour selection
• Down-Sizing in Galaxy Formation at z~1 in the Subaru/XMM-Newton Deep Survey (SXDS)
• How Do Star-Forming Galaxies at Z>3 Assemble Their Masses?
• A wide area survey for high-redshift massive galaxies. I. Number counts and clustering of BzKs and EROs
• The assembly of massive galaxies from NIR observations of the Hubble Deep Field South
• A Bayesian approach to the semi-analytic model of galaxy formation: methodology
• The Fraction of Quiescent Massive Galaxies in the Early Universe
• Bimodal Color Distribution in Hierarchical Galaxy Formation
• A comparison among LBGs, DRGs and BzK galaxies: their contribution to the stellar mass density in the GOODS-MUSIC sample
• The blue UV slopes of z~4 Lyman break galaxies: implications for the corrected star formation rate density
• The Multiwavelength Survey by Yale-Chile (MUSYC): Wide K-band Imaging, Photometric Catalogs, Clustering and Physical Properties of Galaxies at z~2
• Bayesian inference of galaxy formation from the K-band luminosity function of galaxies: tensions between theory and observation
• The clustering and abundance of star-forming and passive galaxies at $z\sim 2$
• The Clustering Evolution of Distant Red Galaxies in the GOODS-MUSIC Sample
• The colour selection of distant galaxies in the UKIDSS Ultra-Deep Survey Early Data Release
• The Cosmic Evolution of Faint Satellite Galaxies as a Test of Galaxy Formation and the Nature of Dark Matter
• Red sequence determination of the redshift of the cluster of galaxies JKCS041: z~2.2
• The numbers of z~2 star-forming and passive galaxies in 2.5 square degrees of deep CFHT imaging
• On the Stellar Populations in Faint Red Galaxies in the Hubble Ultra Deep Field

Cited by in corpus (6)

• The realm of the galaxy protoclusters
• The galaxy stellar mass function at 3.5<z<7.5 in the CANDELS/UDS, GOODS-South, and HUDF fields
• Chasing passive galaxies in the early Universe: a critical analysis in CANDELS GOODS-South
• The Spitzer Matching Survey of the UltraVISTA Ultra-deep Stripes (SMUVS): the Evolution of Dusty and Non-Dusty Galaxies with Stellar Mass at z=2-6
• ${\mu }_{\star }$ Masses: Weak Lensing Calibration of the Dark Energy Survey Year 1 redMaPPer Clusters using Stellar Masses
• LARgE Survey. I. Dead Monsters: the Massive End of the Passive Galaxy Stellar Mass Function at Cosmic Noon