A semi-analytical perspective on massive galaxies at z∼0.55z\sim0.55

The most massive and luminous galaxies in the Universe serve as powerful probes to study the formation of structure, the assembly of mass, and cosmology. However, their detailed formation and evolution is still barely understood. Here we extract a sample of massive mock galaxies from the semi-analytical model of galaxy formation (SAM) GALACTICUS from the MultiDark-Galaxies, by replicating the CMASS photometric selection from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). The comparison of the GALACTICUS CMASS-mock with BOSS-CMASS data allows us to explore different aspects of the massive galaxy population at $0.5<z<0.6$, including the galaxy-halo connection and the galaxy clustering. We find good agreement between our modelled galaxies and observations regarding the galaxy-halo connection, but our CMASS-mock over-estimates the clustering amplitude of the 2-point correlation function, due to a smaller number density compared to BOSS, a lack of blue objects, and a small intrinsic scatter in stellar mass at fixed halo mass of $<0.1$ dex. To alleviate this problem, we construct an alternative mock catalogue mimicking the CMASS colour-magnitude distribution by randomly down-sampling the SAM catalogue. This CMASS-mock reproduces the clustering of CMASS galaxies within 1$\sigma$ and shows some environmental dependency of star formation properties that could be connected to the quenching of star formation and the assembly bias.Comment: 15 pages, 10 figures, 2 tables, submitted to MNRA

How much dark matter is there inside early-type galaxies?

We study the luminous mass as a function of the dynamical mass inside the effective radius (r_e) of early-type galaxies (ETGs) to search for differences between these masses. We assume Newtonian dynamics and that any difference between these masses is due to the presence of dark matter. We use several samples of ETGs -ranging from 19 000 to 98 000 objects- from the ninth data release of the Sloan Digital Sky Survey. We perform Monte Carlo (MC) simulations of galaxy samples and compare them with real samples. The main results are: i) MC simulations show that the distribution of the dynamical vs. luminous mass depends on the mass range where the ETGs are distributed (geometric effect). This dependence is caused by selection effects and intrinsic properties of the ETGs. ii) The amount of dark matter inside r_e is approximately 7% +- 22%. iii) This amount of dark matter is lower than the minimum estimate (10%) found in the literature and four times lower than the average (30%) of literature estimates. However, if we consider the associated error, our estimate is of the order of the literature average.Comment: 24 pages, 12 figures. MNRAS accepte

X-ray Surface Brightness Profiles of Active Galactic Nuclei in the Extended Groth Strip: Implications for AGN Feedback

Using data from the All Wavelength Extended Groth Strip International Survey (AEGIS) we statistically detect the extended X-ray emission in the interstellar medium (ISM)/intra-cluster medium (ICM) in both active and normal galaxies at 0.3 <= z <= 1.3. For both active galactic nuclei (AGN) host galaxy and normal galaxy samples that are matched in restframe color, luminosity, and redshift distribution, we tentatively detect excess X-ray emission at scales of 1--10 arcsec at a few sigma significance in the surface brightness profiles. The exact significance of this detection is sensitive to the true characterization of Chandra's point spread function. The observed excess in the surface brightness profiles is suggestive of lower extended emission in AGN hosts compared to normal galaxies. This is qualitatively similar to theoretical predictions of the X-ray surface brightness profile from AGN feedback models, where feedback from AGN is likely to evacuate the gas from the center of the galaxy/cluster. We propose that AGN that are intrinsically under-luminous in X-rays, but have equivalent bolometric luminosities to our sources will be the ideal sample to study more robustly the effect of AGN feedback on diffuse ISM/ICM gas.Comment: Accepted in PAS

THE BOSS EMISSION-LINE LENS SURVEY. IV. SMOOTH LENS MODELS for the BELLS GALLERY SAMPLE

We present \textsl{Hubble Space Telescope} (\textsl{HST}) F606W-band imaging observations of 21 galaxy-Ly$\alpha$ emitter lens candidates in the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Ly$\alpha$ EmitteR sYstems (BELLS GALLERY) survey. 17 systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately $0.55$, while the lensed sources are Ly$\alpha$ emitters (LAEs) at redshifts from 2 to 3. Although the \textsl{HST} imaging data are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are on average $60\%$ larger than those of the BELLS lenses because of the much higher source redshifts which will allow a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average $\sim 13 \times$ lensing magnification, the LAEs are resolved to comprise individual star-forming knots of a wide range of properties with characteristic sizes from less than 100 pc to several kpc, rest-frame far UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.Comment: 15 pages, 4 figures, minor edits to match the ApJ published versio

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling the clustering and halo occupation distribution of BOSS CMASS galaxies in the Final Data Release

Citation: Rodriguez-Torres, S. A., Chuang, C. H., Prada, F., Guo, H., Klypin, A., Behroozi, P., . . . Thomas, D. (2016). The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling the clustering and halo occupation distribution of BOSS CMASS galaxies in the Final Data Release. Monthly Notices of the Royal Astronomical Society, 460(2), 1173-1187. doi:10.1093/mnras/stw1014We present a study of the clustering and halo occupation distribution of Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies in the redshift range 0.43 cold dark matter Planck cosmology. We compare the observational data with the simulated ones on a light cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fibre collisions are included in the model, which reproduces within 1 sigma errors the observed monopole of the two-point correlation function at all relevant scales: from the smallest scales, 0.5 h(-1) Mpc, up to scales beyond the baryon acoustic oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to k similar to 1 h Mpc(-1)), and the three-point correlation function. The quadrupole of the correlation function presents some tensions with observations. We discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. We compare the stellar-to-halo mass relation for the CMASS sample measured using weak lensing in the Canada-France-Hawaii Telescope Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1 sigma. The BigMD-BOSS light cone including properties of BOSS galaxies and halo properties is made publicly available

The ALHAMBRA survey : B−B-band luminosity function of quiescent and star-forming galaxies at 0.2≤z<10.2 \leq z < 1 by PDF analysis

Our goal is to study the evolution of the $B-$band luminosity function (LF) since $z=1$ using ALHAMBRA data. We used the photometric redshift and the $I-$band selection magnitude probability distribution functions (PDFs) of those ALHAMBRA galaxies with $I\leq24$ mag to compute the posterior LF. We statistically studied quiescent and star-forming galaxies using the template information encoded in the PDFs. The LF covariance matrix in redshift-magnitude-galaxy type space was computed, including the cosmic variance. That was estimated from the intrinsic dispersion of the LF measurements in the 48 ALHAMBRA sub-fields. The uncertainty due to the photometric redshift prior is also included in our analysis. We modelled the LF with a redshift-dependent Schechter function affected by the same selection effects than the data. The measured ALHAMBRA LF at $0.2\leq z<1$ and the evolving Schechter parameters both for quiescent and star-forming galaxies agree with previous results in the literature. The estimated redshift evolution of $M_B^* \propto Qz$ is $Q_{\rm SF}=-1.03\pm0.08$ and $Q_{\rm Q}=-0.80\pm0.08$, and of $\log \phi^* \propto Pz$ is $P_{\rm SF}=-0.01\pm0.03$ and $P_{\rm Q}=-0.41\pm0.05$. The measured faint-end slopes are $\alpha_{\rm SF}=-1.29\pm0.02$ and $\alpha_{\rm Q}=-0.53\pm0.04$. We find a significant population of faint quiescent galaxies, modelled by a second Schechter function with slope $\beta=-1.31\pm0.11$. We find a factor $2.55\pm0.14$ decrease in the luminosity density $j_B$ of star-forming galaxies, and a factor $1.25\pm0.16$ increase in the $j_B$ of quiescent ones since $z=1$, confirming the continuous build-up of the quiescent population with cosmic time. The contribution of the faint quiescent population to $j_B$ increases from 3% at $z=1$ to 6% at $z=0$. The developed methodology will be applied to future multi-filter surveys such as J-PAS.Comment: Accepted for publication in Astronomy and Astrophysics. 25 pages, 20 figures, 7 table

[O II] emitters in MultiDark-Galaxies and DEEP2

We use three semi-analytical models (SAMs) of galaxy formation and evolution run on the same 1 h(-1) Gpc MultiDark Planck2 cosmological simulation to investigate the properties of [O II] emission line galaxies at redshift z similar to 1. We compare model predictions with different observational data sets, including DEEP2-FIREFLY galaxies with absolute magnitudes. We estimate the [O II] luminosity (L[O II]) of our model galaxies using the public code GET EMLINES, which ideally assumes as input the instantaneous star formation rates (SFRs). This property is only available in one of the SAMs under consideration, while the others provide average SFRs, as most models do. We study the feasibility of inferring galaxies' L[O II] from average SFRs in post-processing. We find that the result is accurate for model galaxies with dust attenuated L[O II] less than or similar to 10(42.2) erg s(-1) ( 10(40.4) erg s(-1) remains overall unchanged on scales above 1 h(-1) Mpc, independently of the L[O II] computation. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyGFandVGPacknowledge support from the University of Portsmouth through the Dennis Sciama Fellowship award. VGP acknowledges support from the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant agreement No 769130). DS is funded by the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2014 Severo Ochoa Predoctoral Training Programme. DS also wants to thank the Mamua Cafe Bar-team for their kind (g)astronomical support. DS and FP acknowledge funding support from the MINECO grant AYA2014-60641-C2-1-P. AO acknowledges support from the Spanish Ministerio de Economia y Competitividad (MINECO) project No. AYA2015-66211-C2-P-2, and funding from the European Union Horizon 2020 research and innovation programme under grant agreement No. 734374. SAC acknowledges funding from Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET, PIP0387), Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCyT, PICT-2013-0317), and Universidad Nacional de La Plata (11-G124 and 11-G150), Argentina. CVMacknowledges CONICET, Argentina, for the supporting fellowship. AK is supported by the MINECO and the Fondo Europeo de Desarrollo Regional (FEDER, UE) in Spain through grant AYA2015-63810-P as well as by the MICIU/FEDER through grant number PGC2018-094975-C21. He further acknowledges support from the Spanish Red Consolider MultiDark FPA2017-90566-REDC and thanks Christopher Cross for sailing. ARHS acknowledges receipt of the Jim Buckee Fellowship at ICRAR-UWA. GF, VGP and DS wish to thank La Plata Astronomical Observatory for hosting the MultiDark Galaxies workshop in September 2016, during which this work was started. The authors thank the FIREFLY team and the anonymous referee for providing insightful comments. The analysis of DEEP2 data using the FIREFLY code was done on the Sciama High Performance Compute cluster which is supported by the ICG, SEPNet and the University of Portsmouth (UK). The CosmoSim database used in this paper is a service by the Leibniz-Institute for Astrophysics Potsdam (AIP). The MultiDark database was developed in cooperation with the Spanish MultiDark Consolider Project CSD200900064. The authors gratefully acknowledge the Gauss Centre for Supercomputing e.V. (www.gauss-centre.eu) and the Partnership for Advanced Supercomputing in Europe (PRACE, www.praceri.eu) for funding the MultiDark simulation project by providing computing time on the GCS Supercomputer SuperMUC at Leibniz Supercomputing Centre (LRZ, www.lrz.de).The authors thank New Mexico State University (USA) and Instituto de Astrof ' isica de Andalucia CSIC (Spain) for hosting the SKIES& UNIVERSES database for cosmological simulation products. This work has benefited from the publicly available software tools and packages: MATPLOTLIB14 2012-2016 (Hunter 2007); PYTHON SOFTWARE FOUNDATION15 19902017, version 2.7., PYTHONBREW16; we use whenever possible in this work a colour-blind friendly colour palette17 for our plots.Peer reviewe

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological implications of the large-scale two-point correlation function

We obtain constraints on cosmological parameters from the spherically averaged redshift-space correlation function of the CMASS Data Release 9 (DR9) sample of the Baryonic Oscillation Spectroscopic Survey (BOSS). We combine this information with additional data from recent CMB, SN and BAO measurements. Our results show no significant evidence of deviations from the standard flat-Lambda CDM model, whose basic parameters can be specified by Omega_m = 0.285 +- 0.009, 100 Omega_b = 4.59 +- 0.09, n_s = 0.96 +- 0.009, H_0 = 69.4 +- 0.8 km/s/Mpc and sigma_8 = 0.80 +- 0.02. The CMB+CMASS combination sets tight constraints on the curvature of the Universe, with Omega_k = -0.0043 +- 0.0049, and the tensor-to-scalar amplitude ratio, for which we find r < 0.16 at the 95 per cent confidence level (CL). These data show a clear signature of a deviation from scale-invariance also in the presence of tensor modes, with n_s <1 at the 99.7 per cent CL. We derive constraints on the fraction of massive neutrinos of f_nu < 0.049 (95 per cent CL), implying a limit of sum m_nu < 0.51 eV. We find no signature of a deviation from a cosmological constant from the combination of all datasets, with a constraint of w_DE = -1.033 +- 0.073 when this parameter is assumed time-independent, and no evidence of a departure from this value when it is allowed to evolve as w_DE(a) = w_0 + w_a (1 - a). The achieved accuracy on our cosmological constraints is a clear demonstration of the constraining power of current cosmological observations.Comment: 26 pages, 15 figures. Minor changes to match version accepted by MNRA