The SAMI Galaxy Survey: Detection of Environmental Dependence of Galaxy Spin in Observations and Simulations Using Marked Correlation Functions
Tomas H. Rutherford, Scott M. Croom, Jesse van de Sande, Claudia del P. Lagos, Joss Bland-Hawthorn, S. Brough, Julia J. Bryant, Francesco D'Eugenio, Matt S. Owers
备注：
10 pages, 4 figures, 1 table, accepted in to Astrophysical Journal
The existence of a kinematic morphology-density relation remains uncertain, and instead stellar mass appears the more dominant driver of galaxy kinematics. We investigate the dependence of the stellar spin parameter proxy $λ_{R_e}$ on environment using a marked cross-correlation method with data from the SAMI Galaxy Survey. Our sample contains 710 galaxies with spatially resolved stellar velocity and velocity dispersion measurements. By utilising the highly complete spectroscopic data from the GAMA survey, we calculate marked cross-correlation functions for SAMI galaxies using a pair count estimator and marks based on stellar mass and $λ_{R_e}$. We detect an anti-correlation of stellar kinematics with environment at the 3.2$σ$ level, such that galaxies with low $λ_{R_e}$ values are preferably located in denser galaxy environments. However, a significant correlation between stellar mass and environment is also found (correlation at 2.4$σ$), as found in previous works. We compare these results to mock-observations from the cosmological EAGLE simulations, where we find a similar significant $λ_{R_e}$ anti-correlation with environment, and a mass and environment correlation. We demonstrate that the environmental correlation of $λ_{R_e}$ is not caused by the mass-environment relation. The significant relationship between $λ_{R_e}$ and environment remains when we exclude slow rotators. The signals in SAMI and EAGLE are strongest on small scales (10-100 kpc) as expected from galaxy interactions and mergers. Our work demonstrates that the technique of marked correlation functions is an effective tool for detecting the relationship between $λ_{R_e}$ and environment.
Most dynamical models of galaxies to date assume axisymmetry, which is not representative of a significant fraction of massive galaxies. We have built triaxial orbit-superposition Schwarzschild models of galaxies observed by the SAMI Galaxy Survey, in order to reconstruct their inner orbital structure and mass distribution. The sample consists of 153 passive galaxies with total stellar masses in the range $10^{9.5}$ to $10^{12} M_{\odot}$. We present an analysis of the internal structures and intrinsic properties of these galaxies as a function of their environment. We measure their environmen…
We explore the radial distribution of star formation in galaxies in the SAMI Galaxy Survey as a function of their local group environment. Using a sample of galaxies in groups (with halo masses less than $ \simeq 10^{14} \, \mathrm{M_{\odot}}$) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups ($M_{G} > 10^{12.5} \, \mathrm{M_{\odot}}$). The mean integrated specific star formation rate of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or that are ungrouped, with $Δ\log(sSFR/\mathrm{yr^{-1}}) = 0.…
SAMI and TNG-Cluster: tracing galaxy spin and environmental transformation across cluster phase-space and cosmic time
Universidade Tecnológica Federal do Paraná（帕拉纳联邦技术大学）；European Southern Observatory（欧洲南方天文台）；Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo（圣保罗大学天文、地球物理与大气科学研究所）；University of Dodoma, College of Natural and Mathematical Sciences（多多马大学自然与数理科学学院）
We study environmental quenching using the spatial distribution of current star-formation and stellar population ages with the full SAMI Galaxy Survey. By using a star-formation concentration index [C-index, defined as log10(r_{50,Halpha}/r_{50,cont})], we separate our sample into regular galaxies (C-index>-0.2) and galaxies with centrally concentrated star-formation (SF-concentrated; C-index<-0.2). Concentrated star-formation is a potential indicator of galaxies currently undergoing `outside-in' quenching. Our environments cover ungrouped galaxies, low-mass groups (M_200<10^12.5 M_sun), high-…
We present the ~800 star formation rate maps for the SAMI Galaxy Survey based on Hα emission maps, corrected for dust attenuation via the Balmer decrement, that are included in the SAMI Public Data Release 1. We mask out spaxels contaminated by non-stellar emission using the [O III]/Hβ, [N II]/Hα, [S II]/Hα, and [O I]/Hα line ratios. Using these maps, we examine the global and resolved star-forming main sequences of SAMI galaxies as a function of morphology, environmental density, and stellar mass. Galaxies further below the star-forming main sequence are more likely to have flatter star forma…
We use data from the Sydney-AAO Multi-Object Integral Field Spectrograph (SAMI) Galaxy Survey and the Galaxy And Mass Assembly (GAMA) survey to investigate the spatially-resolved signatures of the environmental quenching of star formation in galaxies. Using dust-corrected measurements of the distribution of H$α$ emission we measure the radial profiles of star formation in a sample of 201 star-forming galaxies covering three orders of magnitude in stellar mass (M$_{*}$; $10^{8.1}$-$10^{10.95}\, $M$_{\odot}$) and in $5^{th}$ nearest neighbour local environment density ($Σ_{5}$; $10^{-1.3}$-$10^{…
We present a new set of index-based measurements of [$α$/Fe] for a sample of 2093 galaxies in the SAMI Galaxy Survey. Following earlier work, we fit a global relation between [$α$/Fe] and the galaxy velocity dispersion $σ$ for red sequence galaxies, [$α$/Fe]=(0.378$\pm$0.009)log($σ$/100)+(0.155$\pm$0.003). We observe a correlation between the residuals and the local environmental surface density, whereas no such relation exists for blue cloud galaxies. In the full sample, we find that elliptical galaxies in high-density environments are $α$-enhanced by up to 0.057$\pm$0.014 dex at velocity dis…
At fixed stellar mass, satellite galaxies show higher passive fractions than centrals, suggesting that environment is directly quenching their star formation. Here, we investigate whether satellite quenching is accompanied by changes in stellar spin (quantified by the ratio of the rotational to dispersion velocity V/$σ$) for a sample of massive ($M_{*}>$10$^{10}$ M$_{\odot}$) satellite galaxies extracted from the SAMI Galaxy Survey. These systems are carefully matched to a control sample of main sequence, high $V/σ$ central galaxies. As expected, at fixed stellar mass and ellipticity, satellit…
In order to determine the causes of kinematic asymmetry in the H$α$ gas in the SAMI Galaxy Survey sample, we investigate the comparative influences of environment and intrinsic properties of galaxies on perturbation. We use spatially resolved H$α$ velocity fields from the SAMI Galaxy Survey to quantify kinematic asymmetry ($\overline{v_{asym}}$) in nearby galaxies and environmental and stellar mass data from the GAMA survey. {We find that local environment, measured as distance to nearest neighbour, is inversely correlated with kinematic asymmetry for galaxies with $\mathrm{\log(M_*/M_\odot)}>…
The kinematic morphology-density relation of galaxies is normally attributed to a changing distribution of galaxy stellar masses with the local environment. However, earlier studies were largely focused on slow rotators; the dynamical properties of the overall population in relation to environment have received less attention. We use the SAMI Galaxy Survey to investigate the dynamical properties of $\sim$1800 early and late-type galaxies with $\log(M_*/M_{\odot})>9.5$ as a function of mean environmental overdensity ($Σ_{5}$) and their rank within a group or cluster. By classifying galaxies int…
We investigate the stellar populations of passive spiral galaxies as a function of mass and environment, using integral field spectroscopy data from the Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey. Our sample consists of $52$ cluster passive spirals and $18$ group/field passive spirals, as well as a set of S0s used as a control sample. The age and [Z/H] estimated by measuring Lick absorption line strength indices both at the center and within $1R_{\rm e}$ do not show a significant difference between the cluster and the field/group passive spirals. However, the field/group…
Large-scale and local environmental drivers of quenching: tracing H$α$ concentration in X-ray and optical galaxy groups
The University of Sydney（悉尼大学）；ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)（三维全天空天体物理学卓越研究中心）；Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）；Beijing Normal University（北京师范大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）
We study the environmental properties of z<1.2 radio-selected AGN belonging to the ~2 square degrees of the COSMOS field, finding that about 20% of them appear within overdense structures. AGN with $P[1.4 GHz]>10^{23.5} W Hz^{-1} sr^{-1}$ are twice more likely to be found in clusters with respect to fainter sources (~38% vs ~15%), just as radio-selected AGN with stellar masses $M*>10^{11} M_\odot$ are twice more likely to be found in overdense environments with respect to objects of lower mass (~24% vs ~11%). Comparisons with galaxy samples further suggest that radio-selected AGN of large stel…
It is suspected that the ultraviolet (UV) upturn phenomenon in elliptical galaxies and extended horizontal-branch stars in globular clusters have a common origin. An extremely high abundance of helium (Y~0.4) allows for a working hypothesis, but its origin is unclear. Peng & Nagai (2009) proposed that primordial helium sedimentation in dark haloes over cosmic timescales may lead to extreme helium abundances in galaxy cluster centers. In this scenario UV upturn should be restricted to brightest cluster galaxies (BCGs) only. This is a clear and testable prediction. We present tests of this hypot…
We investigate how star formation quenching proceeds within central and satellite galaxies using spatially resolved spectroscopy from the SDSS-IV MaNGA DR15. We adopt a complete sample of star formation rate surface densities ($Σ_{\rm SFR}$), derived in Bluck et al. (2020), to compute the distance at which each spaxel resides from the resolved star forming main sequence ($Σ_{\rm SFR} - Σ_*$ relation): $ΔΣ_{\rm SFR}$. We study galaxy radial profiles in $ΔΣ_{\rm SFR}$, and luminosity weighted stellar age (${\rm Age_L}$), split by a variety of intrinsic and environmental parameters. Via several s…
Neutral Hydrogen in the Shapley Supercluster Core I: Environmental Effects on Gas Content and Galaxy Evolution
Rhodes University（罗德斯大学）；INAF–Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；INAF–Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；South African Radio Astronomy Observatory（南非射电天文观测台）
We re-examine the fraction of low-redshift Sloan Digital Sky Survey satellites and centrals in which star formation has been quenched, using the environment quenching efficiency formalism that separates out the dependence of stellar mass. We show that the centrals of the groups containing the satellites are responding to the environment in the same way as their satellites (at least for stellar masses above 10^10.3 Msun), and that the well-known differences between satellites and the general set of centrals arise because the latter are overwhelmingly dominated by isolated galaxies. The widespre…
We investigate how different mid-infrared (mid-IR) properties of galaxies trace the environment in which the galaxies are located. For this purpose, we first study the dependence of galaxy clustering on the absolute magnitude at 3.4 $μ$m and redshift. Then, we look into the environmental dependence of mid-IR luminosities and the galaxy properties derived from these luminosities. We also explore how various infrared galaxy luminosity selections influence the galaxy clustering measurements. We use a set of W1 (3.4 $μ$m) absolute magnitude ($M_\text{W1}$) selected samples from the Galaxy and Mass…
