scholarly journals Probing Galaxy Evolution in Massive Clusters Using ACT and DES: Splashback as a Cosmic Clock

2021 ◽  
Vol 923 (1) ◽  
pp. 37
Author(s):  
Susmita Adhikari ◽  
Tae-hyeon Shin ◽  
Bhuvnesh Jain ◽  
Matt Hilton ◽  
Eric Baxter ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Atacama Cosmology Telescope ◽  
Dark Energy Survey ◽  
Radial Profiles ◽  
Blue Galaxies ◽  
Sunyaev Zel'dovich Effect ◽  
Red Galaxies ◽  
Massive Clusters

Abstract We measure the projected number density profiles of galaxies and the splashback feature in clusters selected by the Sunyaev–Zel’dovich effect from the Advanced Atacama Cosmology Telescope (AdvACT) survey using galaxies observed by the Dark Energy Survey (DES). The splashback radius is consistent with CDM-only simulations and is located at 2.4 − 0.4 + 0.3 Mpc h − 1 . We split the galaxies on color and find significant differences in their profile shapes. Red and green-valley galaxies show a splashback-like minimum in their slope profile consistent with theory, while the bluest galaxies show a weak feature at a smaller radius. We develop a mapping of galaxies to subhalos in simulations and assign colors based on infall time onto their hosts. We find that the shift in location of the steepest slope and different profile shapes can be mapped to the average time of infall of galaxies of different colors. The steepest slope traces a discontinuity in the phase space of dark matter halos. By relating spatial profiles to infall time, we can use splashback as a clock to understand galaxy quenching. We find that red galaxies have on average been in clusters over 3.2 Gyr, green galaxies about 2.2 Gyr, while blue galaxies have been accreted most recently and have not reached apocenter. Using the full radial profiles, we fit a simple quenching model and find that the onset of galaxy quenching occurs after a delay of about a gigayear and that galaxies quench rapidly thereafter with an exponential timescale of 0.6 Gyr.

scholarly journals Deficit of luminous and normal red galaxies in cosmic voids

2019 ◽  
Vol 491 (2) ◽  
pp. 2496-2505
Author(s):  
Sean T Bruton ◽  
Xinyu Dai ◽  
Eduardo Guerras ◽  
Ferah A Munshi
Keyword(s):  
Galaxy Evolution ◽  
Colour Difference ◽  
Density Profiles ◽  
Significant Difference ◽  
Void Galaxies ◽  
Luminous Galaxies ◽  
Main Driver ◽  
Blue Galaxies ◽  
Apparent Colour ◽  
Red Galaxies

ABSTRACT We construct a sample of 10 680 wall galaxies and 3064 void galaxies with MR ≲ −20 by cross-referencing a void catalogue from literature with Baryon Oscillation Spectroscopic Survey (BOSS) CMASS and WiggleZ galaxies, where the CMASS survey targets redder galaxies and the WiggleZ survey targets bluer galaxies. Comparing the density profiles of the red and blue galaxies as a function of the void radius, we find that the number ratio of red-to-blue galaxies increases with distances from the void centres, suggesting a deficit of luminous and normal red galaxies in voids. We find a mean (g – r) magnitude colour of 1.298 and 1.210 for the wall and void galaxies, respectively, when considering the combined red and blue samples, which is found to be a significant difference. However, when considering the blue and red samples separately, we find no significant colour difference. We conclude that the constituents galaxies of each population, rather than intrinsic colour difference, is the main driver in the apparent average colour difference of galaxies in voids and walls, indicating a deficit of luminous and normal red galaxies in voids. Our analysis suggests that the primary environmental-dependence effect on galaxy evolution for normal and luminous galaxies between void and wall regions is manifested in the number of red galaxies, which depends on the environmental-dependent merger history. Using a semi-analytic simulation model, we can successfully reproduce the apparent colour difference between the void and wall galaxies.

scholarly journals The mass and galaxy distribution around SZ-selected clusters

2021 ◽  
Author(s):  
T Shin ◽  
B Jain ◽  
S Adhikari ◽  
E J Baxter ◽  
C Chang ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Theoretical Models ◽  
Weak Lensing ◽  
Mass Selection ◽  
Atacama Cosmology Telescope ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Radial Profiles ◽  
The Galaxy ◽  
Galaxy Sample

Abstract We present measurements of the radial profiles of the mass and galaxy number density around Sunyaev-Zel’dovich (SZ)-selected clusters using both weak lensing and galaxy counts. The clusters are selected from the Atacama Cosmology Telescope Data Release 5 and the galaxies from the Dark Energy Survey Year 3 dataset. With signal-to-noise of 62 (45) for galaxy (weak lensing) profiles over scales of about 0.2 − 20h−1 Mpc, these are the highest precision measurements for SZ-selected clusters to date. Because SZ selection closely approximates mass selection, these measurements enable several tests of theoretical models of the mass and light distribution around clusters. Our main findings are: 1. The splashback feature is detected at a consistent location in both the mass and galaxy profiles and its location is consistent with predictions of cold dark matter N-body simulations. 2. The full mass profile is also consistent with the simulations. 3. The shapes of the galaxy and lensing profiles are remarkably similar for our sample over the entire range of scales, from well inside the cluster halo to the quasilinear regime. We measure the dependence of the profile shapes on the galaxy sample, redshift and cluster mass. We extend the Diemer & Kravtsov model for the cluster profiles to the linear regime using perturbation theory and show that it provides a good match to the measured profiles. We also compare the measured profiles to predictions of the standard halo model and simulations that include hydrodynamics. Applications of these results to cluster mass estimation, cosmology and astrophysics are discussed.

scholarly journals Measurement of the splashback feature around SZ-selected Galaxy clusters with DES, SPT, and ACT

2019 ◽  
Vol 487 (2) ◽  
pp. 2900-2918 ◽  
Author(s):  
T Shin ◽  
S Adhikari ◽  
E J Baxter ◽  
C Chang ◽  
B Jain ◽  
...  
Keyword(s):  
Dark Energy ◽  
Galaxy Clusters ◽  
Selection Effects ◽  
South Pole ◽  
Atacama Cosmology Telescope ◽  
Dark Energy Survey ◽  
South Pole Telescope ◽  
The Galaxy ◽  
Blue Galaxies ◽  
Energy Survey

ABSTRACT We present a detection of the splashback feature around galaxy clusters selected using the Sunyaev–Zel’dovich (SZ) signal. Recent measurements of the splashback feature around optically selected galaxy clusters have found that the splashback radius, rsp, is smaller than predicted by N-body simulations. A possible explanation for this discrepancy is that rsp inferred from the observed radial distribution of galaxies is affected by selection effects related to the optical cluster-finding algorithms. We test this possibility by measuring the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey. The measurement is accomplished by correlating these cluster samples with galaxies detected in the Dark Energy Survey Year 3 data. The SZ observable used to select clusters in this analysis is expected to have a tighter correlation with halo mass and to be more immune to projection effects and aperture-induced biases, potentially ameliorating causes of systematic error for optically selected clusters. We find that the measured rsp for SZ-selected clusters is consistent with the expectations from simulations, although the small number of SZ-selected clusters makes a precise comparison difficult. In agreement with previous work, when using optically selected redMaPPer clusters with similar mass and redshift distributions, rsp is ∼2σ smaller than in the simulations. These results motivate detailed investigations of selection biases in optically selected cluster catalogues and exploration of the splashback feature around larger samples of SZ-selected clusters. Additionally, we investigate trends in the galaxy profile and splashback feature as a function of galaxy colour, finding that blue galaxies have profiles close to a power law with no discernible splashback feature, which is consistent with them being on their first infall into the cluster.

scholarly journals THE ATACAMA COSMOLOGY TELESCOPE: PHYSICAL PROPERTIES OF SUNYAEV-ZEL'DOVICH EFFECT CLUSTERS ON THE CELESTIAL EQUATOR,

2013 ◽  
Vol 765 (1) ◽  
pp. 67 ◽  
Author(s):  
Felipe Menanteau ◽  
Cristóbal Sifón ◽  
L. Felipe Barrientos ◽  
Nicholas Battaglia ◽  
J. Richard Bond ◽  
...  
Keyword(s):  
Physical Properties ◽  
Atacama Cosmology Telescope ◽  
Sunyaev Zel'dovich Effect ◽  
Celestial Equator

scholarly journals The intracluster light as a tracer of the total matter density distribution: a view from simulations

2020 ◽  
Vol 494 (2) ◽  
pp. 1859-1864 ◽  
Author(s):  
Isaac Alonso Asensio ◽  
Claudio Dalla Vecchia ◽  
Yannick M Bahé ◽  
David J Barnes ◽  
Scott T Kay
Keyword(s):  
Mass Density ◽  
Radial Profile ◽  
Stellar Mass ◽  
Matter Density ◽  
Density Profiles ◽  
Radial Profiles ◽  
Intracluster Light ◽  
Baryonic Mass ◽  
Mass Density Profile ◽  
Total Matter

ABSTRACT By using deep observations of clusters of galaxies, it has been recently found that the projected stellar mass density closely follows the projected total (dark and baryonic) mass density within the innermost ∼140 kpc. In this work, we aim to test these observations using the Cluster-EAGLE simulations, comparing the projected densities inferred directly from the simulations. We compare the iso-density contours using the procedure of Montes & Trujillo, and find that the shape of the stellar mass distribution follows that of the total matter even more closely than observed, although their radial profiles differ substantially. The ratio between stellar and total matter density profiles in circular apertures shows a slope close to −1, with a small dependence on the cluster’s total mass. We propose an indirect method to calculate the halo mass and mass density profile from the radial profile of the intracluster stellar mass density.

scholarly journals Structure of Dark Matter Halo

1999 ◽  
Vol 183 ◽  
pp. 155-155
Author(s):  
Toshiyuki Fukushige ◽  
Junichiro Makino
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Temperature Inversion ◽  
Dark Matter Halo ◽  
Temperature Structure ◽  
Galactic Halos ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Order Of Magnitude ◽  
Special Purpose Computer

We performed N-body simulation on special-purpose computer, GRAPE-4, to investigate the structure of dark matter halos (Fukushige, T. and Makino, J. 1997, ApJL, 477, L9). Universal profile proposed by Navarro, Frenk, and White (1996, ApJ, 462, 563), which has cusp with density profiles ρ ∝r−1in density profile, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were based on simulations with relatively few particles, and substantial softening. We performed simulations with particle numbers an order of magnitude higher, and essentially no softening, and found that typical central density profiles are clearly steeper than ρ ∝r−1, as shown in Figure 1. In addition, we confirm the presence of a temperature inversion in the inner 5 kpc of massive galactic halos, and give a natural explanation for formation of the temperature structure.

scholarly journals A method for classification of red, blue, and green galaxies using fuzzy set theory

2020 ◽  
Vol 499 (1) ◽  
pp. L31-L35
Author(s):  
Biswajit Pandey
Keyword(s):  
Fuzzy Sets ◽  
Set Theory ◽  
Fuzzy Set ◽  
Fuzzy Set Theory ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Blue Galaxies ◽  
Boundary Sets ◽  
Red Galaxies

ABSTRACT Red and blue galaxies are traditionally classified using some specific cuts in colour or other galaxy properties, which are supported by empirical arguments. The vagueness associated with such cuts are likely to introduce a significant contamination in these samples. Fuzzy sets are vague boundary sets that can efficiently capture the classification uncertainty in the absence of any precise boundary. We propose a method for classification of galaxies according to their colours using fuzzy set theory. We use data from the Sloan Digital Sky Survey (SDSS) to construct a fuzzy set for red galaxies with its members having different degrees of ‘redness’. We show that the fuzzy sets for the blue and green galaxies can be obtained from it using different fuzzy operations. We also explore the possibility of using fuzzy relation to study the relationship between different galaxy properties and discuss its strengths and limitations.

scholarly journals C iv black hole mass measurements with the Australian Dark Energy Survey (OzDES)

2019 ◽  
Vol 487 (3) ◽  
pp. 3650-3663 ◽  
Author(s):  
J K Hoormann ◽  
P Martini ◽  
T M Davis ◽  
A King ◽  
C Lidman ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Energy ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Supermassive Black Holes ◽  
Black Hole Mass ◽  
Mass Measurements ◽  
Dark Energy Survey ◽  
Energy Survey

ABSTRACT Black hole mass measurements outside the local Universe are critically important to derive the growth of supermassive black holes over cosmic time, and to study the interplay between black hole growth and galaxy evolution. In this paper, we present two measurements of supermassive black hole masses from reverberation mapping (RM) of the broad C iv emission line. These measurements are based on multiyear photometry and spectroscopy from the Dark Energy Survey Supernova Program (DES-SN) and the Australian Dark Energy Survey (OzDES), which together constitute the OzDES RM Program. The observed reverberation lag between the DES continuum photometry and the OzDES emission line fluxes is measured to be $358^{+126}_{-123}$ and $343^{+58}_{-84}$ d for two quasars at redshifts of 1.905 and 2.593, respectively. The corresponding masses of the two supermassive black holes are 4.4 × 109 and 3.3 × 109 M⊙, which are among the highest redshift and highest mass black holes measured to date with RM studies. We use these new measurements to better determine the C iv radius−luminosity relationship for high-luminosity quasars, which is fundamental to many quasar black hole mass estimates and demographic studies.

scholarly journals Spatially resolved signature of quenching in star-forming galaxies

2019 ◽  
Vol 490 (2) ◽  
pp. 2347-2366 ◽  
Author(s):  
Salvatore Quai ◽  
Lucia Pozzetti ◽  
Michele Moresco ◽  
Annalisa Citro ◽  
Andrea Cimatti ◽  
...  
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Galaxy Evolution ◽  
Spatial Information ◽  
Formation Rate ◽  
Radial Profile ◽  
Control Sample ◽  
Star Forming ◽  
Radial Profiles ◽  
Two Samples

ABSTRACT Understanding when, how, and where star formation ceased (quenching) within galaxies is still a critical subject in galaxy evolution studies. Taking advantage of the new methodology developed by Quai et al. to select recently quenched galaxies, we explored the spatial information provided by the IFU data to get critical insights on this process. In particular, we analyse 10 SDSS-IV MaNGA galaxies that show regions with low [O iii]/H α compatible with a recent quenching of the star formation. We compare the properties of these 10 galaxies with those of a control sample of 8 MaNGA galaxies with ongoing star formation in the same stellar mass, redshift, and gas-phase metallicity range. The quenching regions found are located between 0.5 and 1.1 effective radii from the centre. This result is supported by the analysis of the average radial profile of the ionization parameter, which reaches a minimum at the same radii, while the one of the star-forming sample shows an almost flat trend. These quenching regions occupy a total area between ∼ 15 and 45 per cent of our galaxies. Moreover, the average radial profile of the star formation rate surface density of our sample is lower and flatter than that of the control sample, at any radii, suggesting a systematic suppression of the star formation in the inner part of our galaxies. Finally, the radial profiles of gas-phase metallicity of the two samples have a similar slope and normalization. Our results cannot be ascribed to a difference in the intrinsic properties of the analysed galaxies, suggesting a quenching scenario more complicated than a simple inside-out quenching.

Stellar Populations of the Outer Milky-Way Halo

2017 ◽  
Vol 13 (S334) ◽  
pp. 29-33
Author(s):  
Baslio Santiago ◽  
Elmer Luque ◽  
Adriano Pieres ◽  
Anna Bárbara Queiroz
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Milky Way ◽  
Galactic Halo ◽  
Dwarf Galaxy ◽  
Building Blocks ◽  
Early Stages ◽  
Dark Energy Survey ◽  
Stellar Streams ◽  
The Galaxy

AbstractThe stellar spheroidal components of the Milky-Way contain the oldest and most metal poor of its stars. Inevitably the processes governing the early stages of Galaxy evolution are imprinted upon them. According to the currently favoured hierarchical bottom-up scenario of galaxy formation, these components, specially the Galactic halo, are the repository of most of the mass built up from accretion events in those early stages. These events are still going on today, as attested by the long stellar streams associated to the Sagittarius dwarf galaxy and several other observed tidal substructure, whose geometry, extent, and kinematics are important constraints to reconstruct the MW gravitational potential and infer its total (visible + dark) mass. In addition, the remaining system of MW satellites is expected to be a fossil record of the much larger population of Galactic building blocks that once existed and got accreted. For all these reasons, it is crucial to unravel as much of this remaining population as possible, as well as the current stellar streams that orbit within the halo. The best bet to achieve this task is to carry out wide, deep, and multi-band photometric surveys that provide homogeneous stellar samples. In this contribution, we summarize the results of several years of work towards detecting and characterizing distant MW stellar systems, star clusters and dwarf spheroidals alike, with an emphasis on the analysis of data from the Dark Energy Survey (DES). We argue that most of the volume in distance, size and luminosity space, both in the Galaxy and in the Clouds, is still unprobed. We then discuss the perspectives of exploring this outer MW volume using the current surveys, as well as other current and future surveys, such as the Large Synoptic Survey Telescope (LSST).

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