On the (Lack of) Evolution of the Stellar Mass Function of Massive Galaxies from z = 1.5 to 0.4

Abstract

We study the evolution in the number density of the highest mass galaxies over 0.4 < z < 1.5 (covering 9 Gyr). We use the Spitzer/HETDEX Exploratory Large-Area (SHELA) Survey, which covers 17.5 deg 2 with eight photometric bands spanning 0.3-4.5 µm within the SDSS Stripe 82 field. This size produces the lowest counting uncertainties and cosmic variance yet for massive galaxies at z ∼ 1.0. We study the stellar mass function (SMF) for galaxies with log(M * /M ) > 10.3 using a forward-modeling method that fully accounts for statistical and systematic uncertainties on stellar mass. From z=0.4 to 1.5 the massive end of the SMF shows minimal evolution in its shape: the characteristic mass (M * ) evolves by less than 0.1 dex (±0.05 dex); the number density of galaxies with log M * /M > 11 stays roughly constant at log(n/Mpc −3 ) −3.4 (±0.05), then declines to log n/Mpc −3 =−3.7 (±0.05) at z=1.5. We discuss the uncertainties in the SMF, which are dominated by assumptions in the star formation history and details of stellar population synthesis models for stellar mass estimations. For quiescent galaxies, the data are consistent with no (or slight) evolution ( 0.1 dex) in the characteristic mass nor number density from z ∼ 1.5 to the present. This implies that any mass growth (presumably through "dry' mergers) of the quiescent massive galaxy population must balance the rate of mass losses from late-stage stellar evolution and the formation of quenching galaxies from the star-forming population. We provide a limit on this mass growth from z = 1.0 to 0.4 of ∆M * /M * ≤ 45% (i.e., 0.16 dex) for quiescent galaxies more massive than 10 11 M .

J-PLUS: The star formation main sequence and rate density at d ≲ 75 Mpc

“…The correlation between different luminosities due to the cosmic variance is typically 0.4 − 0.8 (Smith 2012;López-Sanjuan et al 2017;Kawinwanichakij et al 2020). We decided to not include the cosmic variance in the analysis of the HαLF in Sect.…”

The evolution of compact massive quiescent and star-forming galaxies derived from the Re–Rh and Mstar–Mh relations

“…The evolution of that we predict for compact quiescent MGs is in qualitative agreement with observations of compact galaxies in a lower mass range (10.5 < / < 11.5, Cassata et al 2011Cassata et al , 2013van der Wel et al 2014;Barro et al 2013). However, at present, current observations provide rather uncertain constraints on at high redshift (see Kawinwanichakij et al 2020 for a detailed discussion of the systematics). In addition, a secure determination of the number density of, especially compact, MGs is hampered by the seizable but still unknown number of optically dark starforming galaxies at high redshift (e.g., Franco et al 2018;Wang et al 2019;Zhou et al 2020;Smail et al 2021).…”

“…There is no consensus yet as to why MGs were a factor of 3 to 5 smaller in the past. Minor dry mergers have been invoked as an efficient channel to promote substantial size increase with relatively modest change in stellar mass (e.g., Naab et al 2009,Oser et al 2010, van Dokkum et al 2015 to accomodate for the limited evolution in the high-mass end of the stellar mass function (SMF) since ∼ 1.5 (e.g., Andreon 2013,Muzzin et al 2013, McDermid et al 2015, Kawinwanichakij et al 2020). However, the rate of minor dry mergers may not be sufficient by themselves to account for the entire size evolution of MGs through cosmic time (Newman et al 2012;Nipoti et al 2009Nipoti et al , 2012.…”

“…The only notable exception is the work by Mowla et al (2019), where however only 1 Ultimately, the reasons for these discrepancies are thought to originate from the way stellar masses are estimated. The Initial Mass Function, dust attenuation curve, stellar population synthesis models and assumed star formation histories, the inclusion of intra-cluster light and even the photometry choice and background subtraction algorithms all contribute to the various determinations of the stellar mass functions found in the literature (see, e.g., Bernardi et al 2010Bernardi et al , 2013Bernardi et al , 2016Bernardi et al , 2017Kravtsov et al 2018;Leja et al 2020;Lower et al 2020;Guarnieri et al 2019;Kawinwanichakij et al 2020 amongst many others), which result in different estimates of the SMHM relation (e.g., Shankar et al 2017) 2 This was necessary to reproduce the full size distribution of early-and late-type MGs in the local Universe as measured in the Sloan digital Sky Survey (SDSS).…”

“…Our present work lays out an effective strategy to unveil the evolutionary pathways of MGs by exploiting the increased statistics of MGs that will become available from future observations. Data for MGs are in fact at present quite sparse and uncertain at 1 (e.g., Kawinwanichakij et al 2020), and effective radii have been measured for only a handful of MGs at 2 (e.g., Kubo et al 2017;Patel et al 2017;Faisst et al 2017;Mowla et al 2018;Stockmann et al 2020;Lustig et al 2021).…”