scholarly journals The evolution of the UV luminosity and stellar mass functions of Lyman-α emitters from z ∼ 2 to z ∼ 6

Author(s):  
S Santos ◽  
D Sobral ◽  
J Butterworth ◽  
A Paulino-Afonso ◽  
B Ribeiro ◽  
...  

Abstract We measure the evolution of the rest-frame UV luminosity function (LF) and the stellar mass function (SMF) of Lyman-α (Lyα) emitters (LAEs) from z ∼ 2 to z ∼ 6 by exploring ∼4000 LAEs from the SC4K sample. We find a correlation between Lyα luminosity (LLyα) and rest-frame UV (MUV), with best-fit M$_{\rm UV}=-1.6_{-0.3}^{+0.2}\log _{10} (\rm L_{Ly\alpha }/erg\, s^{-1})+47_{-11}^{+12}$ and a shallower relation between LLyα and stellar mass (M⋆), with best-fit $\log _{10} (\rm M_\star /{\rm M}_\odot )=0.9_{-0.1}^{+0.1}\log _{10} (\rm L_{Ly\alpha }/erg\, s^{-1})-28_{-3.8}^{+4.0}$. An increasing LLyα cut predominantly lowers the number density of faint MUV and low M⋆ LAEs. We estimate a proxy for the full UV LFs and SMFs of LAEs with simple assumptions of the faint end slope. For the UV LF, we find a brightening of the characteristic UV luminosity (M$_{\rm UV}^*$) with increasing redshift and a decrease of the characteristic number density (Φ*). For the SMF, we measure a characteristic stellar mass (${\rm M_\star ^*/{\rm M}_\odot }$) increase with increasing redshift, and a Φ* decline. However, if we apply a uniform luminosity cut of $\log _{10} (\rm L_{Ly\alpha }/erg\, s^{-1}) \ge 43.0$, we find much milder to no evolution in the UV and SMF of LAEs. The UV luminosity density (ρUV) of the full sample of LAEs shows moderate evolution and the stellar mass density (ρM) decreases, with both being always lower than the total ρUV and ρM of more typical galaxies but slowly approaching them with increasing redshift. Overall, our results indicate that both ρUV and ρM of LAEs slowly approach the measurements of continuum-selected galaxies at z > 6, which suggests a key role of LAEs in the epoch of reionisation.

2017 ◽  
Vol 605 ◽  
pp. A70 ◽  
Author(s):  
I. Davidzon ◽  
O. Ilbert ◽  
C. Laigle ◽  
J. Coupon ◽  
H. J. McCracken ◽  
...  

We measure the stellar mass function (SMF) and stellar mass density of galaxies in the COSMOS field up to z ~ 6. We select them in the near-IR bands of the COSMOS2015 catalogue, which includes ultra-deep photometry from UltraVISTA-DR2, SPLASH, and Subaru/Hyper Suprime-Cam. At z> 2.5 we use new precise photometric redshifts with error σz = 0.03(1 + z) and an outlier fraction of 12%, estimated by means of the unique spectroscopic sample of COSMOS (~100 000 spectroscopic measurements in total, more than one thousand having robust zspec> 2.5). The increased exposure time in the DR2, along with our panchromatic detection strategy, allow us to improve the completeness at high z with respect to previous UltraVISTA catalogues (e.g. our sample is >75% complete at 1010 ℳ⊙ and z = 5). We also identify passive galaxies through a robust colour–colour selection, extending their SMF estimate up to z = 4. Our work provides a comprehensive view of galaxy-stellar-mass assembly between z = 0.1 and 6, for the first time using consistent estimates across the entire redshift range. We fit these measurements with a Schechter function, correcting for Eddington bias. We compare the SMF fit with the halo mass function predicted from ΛCDM simulations, finding that at z> 3 both functions decline with a similar slope in thehigh-mass end. This feature could be explained assuming that mechanisms quenching star formation in massive haloes become less effective at high redshifts; however further work needs to be done to confirm this scenario. Concerning the SMF low-mass end, it shows a progressive steepening as it moves towards higher redshifts, with α decreasing from -1.47+0.02-0.02 at z ≃ 0.1 to -2.11+0.30-0.13 at z ≃ 5. This slope depends on the characterisation of the observational uncertainties, which is crucial to properly remove the Eddington bias. We show that there is currently no consensus on the method to quantify such errors: different error models result in different best-fit Schechter parameters.


2018 ◽  
Vol 614 ◽  
pp. A43 ◽  
Author(s):  
Sami Dib ◽  
Shantanu Basu

We investigate the dependence of a single-generation galactic mass function (SGMF) on variations in the initial stellar mass functions (IMF) of stellar clusters. We show that cluster-to-cluster variations of the IMF lead to a multi-component SGMF where each component in a given mass range can be described by a distinct power-law function. We also show that a dispersion of ≈0.3 M⊙ in the characteristic mass of the IMF, as observed for young Galactic clusters, leads to a low-mass slope of the SGMF that matches the observed Galactic stellar mass function even when the IMFs in the low-mass end of individual clusters are much steeper.


Author(s):  
P Bonfini ◽  
A Zezas ◽  
M L N Ashby ◽  
S P Willner ◽  
A Maragkoudakis ◽  
...  

Abstract We constrain the mass distribution in nearby, star-forming galaxies with the Star Formation Reference Survey (SFRS), a galaxy sample constructed to be representative of all known combinations of star formation rate (SFR), dust temperature, and specific star formation rate (sSFR) that exist in the Local Universe. An innovative two-dimensional bulge/disk decomposition of the 2MASS/Ks-band images of the SFRS galaxies yields global luminosity and stellar mass functions, along with separate mass functions for their bulges and disks. These accurate mass functions cover the full range from dwarf galaxies to large spirals, and are representative of star-forming galaxies selected based on their infra-red luminosity, unbiased by AGN content and environment. We measure an integrated luminosity density j = 1.72 ± 0.93 × 109 L⊙  h−1 Mpc−3 and a total stellar mass density ρM = 4.61 ± 2.40 × 108 M⊙  h−1 Mpc−3. While the stellar mass of the average star-forming galaxy is equally distributed between its sub-components, disks globally dominate the mass density budget by a ratio 4:1 with respect to bulges. In particular, our functions suggest that recent star formation happened primarily in massive systems, where they have yielded a disk stellar mass density larger than that of bulges by more than 1 dex. Our results constitute a reference benchmark for models addressing the assembly of stellar mass on the bulges and disks of local (z = 0) star-forming galaxies.


2019 ◽  
Vol 491 (4) ◽  
pp. 5073-5082 ◽  
Author(s):  
F Pozzi ◽  
F Calura ◽  
G Zamorani ◽  
I Delvecchio ◽  
C Gruppioni ◽  
...  

ABSTRACT We derive for the first time the dust mass function (DMF) in a wide redshift range, from z ∼ 0.2 up to z ∼ 2.5. In order to trace the dust emission, we start from a far-IR (160-μm) Herschel selected catalogue in the COSMOS field. We estimate the dust masses by fitting the far-IR data (λrest$\,\, \buildrel\gt \over \sim \,\,$50 μm) with a modified black body function and we present a detailed analysis to take into account the incompleteness in dust masses from a far-IR perspective. By parametrizing the observed DMF with a Schechter function in the redshift range 0.1 < z ≤ 0.25, where we are able to sample faint dust masses, we measure a steep slope (α ∼1.48), as found by the majority of works in the Local Universe. We detect a strong dust mass evolution, with $M_{\rm d}^{\star }$ at z ∼ 2.5 almost 1 dex larger than in the local Universe, combined with a decrease in their number density. Integrating our DMFs, we estimate the dust mass density (DMD), finding a broad peak at z ∼ 1, with a decrease by a factor of ∼ 3 towards z ∼ 0 and z ∼ 2.5. In general, the trend found for the DMD mostly agrees with the derivation of Driver et al., another DMD determination based also on far-IR detections, and with other measures based on indirect tracers.


Author(s):  
Aldo Rodríguez-Puebla ◽  
A. R. Calette ◽  
Vladimir Avila-Reese ◽  
Vicente Rodriguez-Gomez ◽  
Marc Huertas-Company

Abstract We report the bivariate $\rm HI$ - and $\rm H_{2}$ -stellar mass distributions of local galaxies in addition of an inventory of galaxy mass functions, MFs, for $\rm HI$ , $\rm H_{2}$ , cold gas, and baryonic mass, separately into early- and late-type galaxies. The MFs are determined using the $\rm HI$ and $\rm H_{2}$ conditional distributions and the galaxy stellar mass function (GSMF). For the conditional distributions we use the results from the compilation presented in Calette et al. [(2018) RMxAA, 54, 443.]. For determining the GSMF from $M_{*}\sim3\times10^{7}$ to $3\times10^{12}\ \text{M}_{\odot}$ , we combine two spectroscopic samples from the Sloan Digital Sky Survey at the redshift range $0.0033<z<0.2$ . We find that the low-mass end slope of the GSMF, after correcting from surface brightness incompleteness, is $\alpha\approx-1.4$ , consistent with previous determinations. The obtained $\rm HI\,$ MFs agree with radio blind surveys. Similarly, the $\rm H_{2}\,$ MFs are consistent with CO follow-up optically-selected samples. We estimate the impact of systematics due to mass-to-light ratios and find that our MFs are robust against systematic errors. We deconvolve our MFs from random errors to obtain the intrinsic MFs. Using the MFs, we calculate cosmic density parameters of all the baryonic components. Baryons locked inside galaxies represent 5.4% of the universal baryon content, while $\sim\! 96\%$ of the $\rm HI$ and $\rm H_{2}$ mass inside galaxies reside in late-type morphologies. Our results imply cosmic depletion times of $\rm H_{2}$ and total neutral H in late-type galaxies of $\sim\!1.3$ and 7.2 Gyr, respectively, which shows that late type galaxies are on average inefficient in converting $\rm H_{2}$ into stars and in transforming $\rm HI$ gas into $\rm H_{2}$ . Our results provide a fully self-consistent empirical description of galaxy demographics in terms of the bivariate gas–stellar mass distribution and their projections, the MFs. This description is ideal to compare and/or to constrain galaxy formation models.


2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
Douglas Rubin ◽  
Abraham Loeb

The dense concentration of stars and high-velocity dispersions in the Galactic center imply that stellar collisions frequently occur. Stellar collisions could therefore result in significant mass loss rates. We calculate the amount of stellar mass lost due to indirect and direct stellar collisions and find its dependence on the present-day mass function of stars. We find that the total mass loss rate in the Galactic center due to stellar collisions is sensitive to the present-day mass function adopted. We use the observed diffuse X-ray luminosity in the Galactic center to preclude any present-day mass functions that result in mass loss rates>10-5M⨀yr−1in the vicinity of~1″. For present-day mass functions of the form,dN/dM∝M-α, we constrain the present-day mass function to have a minimum stellar mass≲7M⨀and a power-law slope≳1.25. We also use this result to constrain the initial mass function in the Galactic center by considering different star formation scenarios.


2003 ◽  
Vol 599 (2) ◽  
pp. 847-864 ◽  
Author(s):  
Gregory Rudnick ◽  
Hans‐Walter Rix ◽  
Marijn Franx ◽  
Ivo Labbe ◽  
Michael Blanton ◽  
...  

2021 ◽  
Vol 922 (1) ◽  
pp. 89
Author(s):  
Masato Shirasaki ◽  
Tomoaki Ishiyama ◽  
Shin’ichiro Ando

Abstract We study halo mass functions with high-resolution N-body simulations under a ΛCDM cosmology. Our simulations adopt the cosmological model that is consistent with recent measurements of the cosmic microwave backgrounds with the Planck satellite. We calibrate the halo mass functions for 108.5 ≲ M vir/(h −1 M ⊙) ≲ 1015.0–0.45 z , where M vir is the virial spherical-overdensity mass and redshift z ranges from 0 to 7. The halo mass function in our simulations can be fitted by a four-parameter model over a wide range of halo masses and redshifts, while we require some redshift evolution of the fitting parameters. Our new fitting formula of the mass function has a 5%-level precision, except for the highest masses at z ≤ 7. Our model predicts that the analytic prediction in Sheth & Tormen would overestimate the halo abundance at z = 6 with M vir = 108.5–10 h −1 M ⊙ by 20%–30%. Our calibrated halo mass function provides a baseline model to constrain warm dark matter (WDM) by high-z galaxy number counts. We compare a cumulative luminosity function of galaxies at z = 6 with the total halo abundance based on our model and a recently proposed WDM correction. We find that WDM with its mass lighter than 2.71 keV is incompatible with the observed galaxy number density at a 2σ confidence level.


2020 ◽  
Vol 638 ◽  
pp. A112 ◽  
Author(s):  
Remco F. J. van der Burg ◽  
Gregory Rudnick ◽  
Michael L. Balogh ◽  
Adam Muzzin ◽  
Chris Lidman ◽  
...  

We study the stellar mass functions (SMFs) of star-forming and quiescent galaxies in 11 galaxy clusters at 1.0 < z < 1.4 drawn from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. Based on more than 500 h of Gemini/GMOS spectroscopy and deep multi-band photometry taken with a range of observatories, we probe the SMFs down to a stellar mass limit of 109.7 M⊙ (109.5 M⊙ for star-forming galaxies). At this early epoch, the fraction of quiescent galaxies is already highly elevated in the clusters compared to the field at the same redshift. The quenched fraction excess (QFE) represents the fraction of galaxies that would be star-forming in the field but are quenched due to their environment. The QFE is strongly mass dependent, and increases from ∼30% at M⋆ = 109.7 M⊙ to ∼80% at M⋆ = 1011.0 M⊙. Nonetheless, the shapes of the SMFs of the two individual galaxy types, star-forming and quiescent galaxies, are identical between cluster and field to high statistical precision. Nevertheless, along with the different quiescent fractions, the total galaxy SMF is also environmentally dependent, with a relative deficit of low-mass galaxies in the clusters. These results are in stark contrast with findings in the local Universe, and therefore require a substantially different quenching mode to operate at early times. We discuss these results in light of several popular quenching models.


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