scholarly journals The SAMI Galaxy Survey: Mass and Environment as Independent Drivers of Galaxy Dynamics

2021 ◽  
Author(s):  
Jesse van de Sande ◽  
Scott M Croom ◽  
Joss Bland-Hawthorn ◽  
Luca Cortese ◽  
Nicholas Scott ◽  
...  
Keyword(s):  
Local Environment ◽  
Stellar Mass ◽  
High Mass ◽  
Galaxy Dynamics ◽  
Density Relation ◽  
Galaxy Kinematics ◽  
The Mean ◽  
Dynamical Properties ◽  
Stellar Masses ◽  
Kinematic Properties

Abstract 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 ∼1800 early and late-type galaxies with log (M⋆/M⊙) > 9.5 as a function of mean environmental overdensity (Σ5) and their rank within a group or cluster. By classifying galaxies into fast and slow rotators, at fixed stellar mass above log (M⋆/M⊙) > 10.5, we detect a higher fraction (∼3.4σ) of slow rotators for group and cluster centrals and satellites as compared to isolated-central galaxies. We find similar results when using Σ5 as a tracer for environment. Focusing on the fast-rotator population, we also detect a significant correlation between galaxy kinematics and their stellar mass as well as the environment they are in. Specifically, by using inclination-corrected or intrinsic $\lambda _{R_{\rm {e}}}$ values, we find that, at fixed mass, satellite galaxies on average have the lowest $\lambda _{\, R_{\rm {e}},\rm {intr}}$, isolated-central galaxies have the highest $\lambda _{\, R_{\rm {e}},\rm {intr}}$, and group and cluster centrals lie in between. Similarly, galaxies in high-density environments have lower mean $\lambda _{\, R_{\rm {e}},\rm {intr}}$ values as compared to galaxies at low environmental density. However, at fixed Σ5, the mean $\lambda _{\, R_{\rm {e}},\rm {intr}}$ differences for low and high-mass galaxies are of similar magnitude as when varying Σ5 ($\Delta \lambda _{\, R_{\rm {e}},\rm {intr}} \sim 0.05$, with σrandom = 0.025, and σsyst < 0.03). Our results demonstrate that after stellar mass, environment plays a significant role in the creation of slow rotators, while for fast rotators we also detect an independent, albeit smaller, impact of mass and environment on their kinematic properties.

scholarly journals Correlations between H α equivalent width and galaxy properties at z = 0.47: Physical or selection-driven?

2021 ◽  
Vol 503 (4) ◽  
pp. 5115-5133
Author(s):  
A A Khostovan ◽  
S Malhotra ◽  
J E Rhoads ◽  
S Harish ◽  
C Jiang ◽  
...  
Keyword(s):  
Star Formation ◽  
Equivalent Width ◽  
Luminosity Function ◽  
Mass Function ◽  
Stellar Mass ◽  
High Mass ◽  
Selection Effects ◽  
Star Formation Activity ◽  
Low Mass ◽  
Stellar Masses

ABSTRACT The H α equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the H α EW strongly anticorrelates with stellar mass as M−0.25 similar to the sSFR – stellar mass relation. However, such a correlation could be driven or even formed by selection effects. In this study, we investigate how H α EW distributions correlate with physical properties of galaxies and how selection biases could alter such correlations using a z = 0.47 narrow-band-selected sample of 1572 H α emitters from the Ly α Galaxies in the Epoch of Reionization (LAGER) survey as our observational case study. The sample covers a 3 deg2 area of COSMOS with a survey comoving volume of 1.1 × 105 Mpc3. We assume an intrinsic EW distribution to form mock samples of H α emitters and propagate the selection criteria to match observations, giving us control on how selection biases can affect the underlying results. We find that H α EW intrinsically correlates with stellar mass as W0∝M−0.16 ± 0.03 and decreases by a factor of ∼3 from 107 M⊙ to 1010 M⊙, while not correcting for selection effects steepens the correlation as M−0.25 ± 0.04. We find low-mass H α emitters to be ∼320 times more likely to have rest-frame EW>200 Å compared to high-mass H α emitters. Combining the intrinsic W0–stellar mass correlation with an observed stellar mass function correctly reproduces the observed H α luminosity function, while not correcting for selection effects underestimates the number of bright emitters. This suggests that the W0–stellar mass correlation when corrected for selection effects is physically significant and reproduces three statistical distributions of galaxy populations (line luminosity function, stellar mass function, EW distribution). At lower stellar masses, we find there are more high-EW outliers compared to high stellar masses, even after we take into account selection effects. Our results suggest that high sSFR outliers indicative of bursty star formation activity are intrinsically more prevalent in low-mass H α emitters and not a byproduct of selection effects.

scholarly journals Satellite galaxies in the Illustris-1 simulation: anisotropic locations around relatively isolated hosts

2019 ◽  
Vol 489 (1) ◽  
pp. 459-469 ◽  
Author(s):  
Tereasa G Brainerd ◽  
Masaya Yamamoto
Keyword(s):  
Dark Matter ◽  
Mass Density ◽  
Stellar Mass ◽  
Stellar Surface ◽  
Surface Mass ◽  
Degree Of Anisotropy ◽  
Surface Mass Density ◽  
The Mean ◽  
Satellite Galaxies ◽  
Stellar Masses

ABSTRACT We investigate the locations of satellite galaxies in the z = 0 redshift slice of the hydrodynamical Illustris-1 simulation. As expected from previous work, the satellites are distributed anisotropically in the plane of the sky, with a preference for being located near the major axes of their hosts. Due to misalignment of mass and light within the hosts, the degree of anisotropy is considerably less when satellite locations are measured with respect to the hosts’ stellar surface mass density than when they are measured with respect to the hosts’ dark matter surface mass density. When measured with respect to the hosts’ dark matter surface mass density, the mean satellite location depends strongly on host stellar mass and luminosity, with the satellites of the faintest, least massive hosts showing the greatest anisotropy. When measured with respect to the hosts’ stellar surface mass density, the mean satellite location is essentially independent of host stellar mass and luminosity. In addition, the satellite locations are largely insensitive to the amount of stellar mass used to define the hosts’ stellar surface mass density, as long as at least 50–70 per cent of the hosts’ total stellar mass is used. The satellite locations are dependent upon the stellar masses of the satellites, with the most massive satellites having the most anisotropic distributions.

scholarly journals Tidal evolution of galaxies in the most massive cluster of IllustrisTNG-100

2020 ◽  
Vol 638 ◽  
pp. A133 ◽  
Author(s):  
Ewa L. Łokas
Keyword(s):  
Dark Matter ◽  
Stellar Mass ◽  
Tidal Force ◽  
Tidal Evolution ◽  
Evolution Of Galaxies ◽  
Density Relation ◽  
Stellar Masses ◽  
Massive Cluster ◽  
Over Time

We study the tidal evolution of galaxies in the most massive cluster of the IllustrisTNG-100 simulation. For the purpose of this work, we selected 112 galaxies with the largest stellar masses at present and followed their properties over time. Using their orbital history, we divided the sample into unevolved (infalling), weakly evolved (with one pericenter passage), and strongly evolved (with multiple pericenters). The samples are clearly separated by the value of the integrated tidal force from the cluster the galaxies experienced during their entire evolution and their properties depend strongly on this quantity. As a result of tidal stripping, the galaxies of the weakly evolved sample lost between 10 and 80% of their dark mass and less than 10% of stars, while those in the strongly evolved one lost more than 70% of dark mass and between 10 and 55% of stellar mass, and are significantly less, or not at all dark-matter dominated. While 33% of the infalling galaxies do not contain any gas, this fraction increases to 67% for the weakly evolved sample, and to 100% for the strongly evolved sample. The strongly evolved galaxies lose their gas earlier and faster (within 2–6 Gyr), but the process can take up to 4 Gyr from the first pericenter passage. These galaxies are redder and more metal rich, and at redshift z = 0.5, the population of galaxies in the cluster becomes predominantly red. As a result of tidal stirring, the morphology of the galaxies evolves from oblate to prolate and their rotation is diminished, thus the morphology-density relation is reproduced in the simulated cluster. The strongly evolved sample contains at least six convincing examples of tidally induced bars and six more galaxies that had their bars enhanced by their interaction with the cluster.

scholarly journals Is there a fundamental upper limit to the mass of a star cluster?

2019 ◽  
Vol 488 (4) ◽  
pp. 5400-5408 ◽  
Author(s):  
Mark A Norris ◽  
Glenn van de Ven ◽  
Sheila J Kannappan ◽  
Eva Schinnerer ◽  
Ryan Leaman
Keyword(s):  
Cluster Formation ◽  
Star Clusters ◽  
Stellar Mass ◽  
Star Cluster ◽  
High Mass ◽  
Mass Star ◽  
Exact Nature ◽  
Turn Of The Millennium ◽  
Stellar Masses ◽  
Mass Dependent

Abstract The discovery around the turn of the millennium of a population of very massive (M⋆ > 2 × 106 M⊙) compact stellar systems (CSS) with physical properties (radius, velocity dispersion, stellar mass etc.) that are intermediate between those of the classical globular cluster (GC) population and galaxies led to questions about their exact nature. Recently a consensus has emerged that these objects, usually called ultracompact dwarfs (UCDs), are a mass-dependent mixture of high-mass star clusters and remnant nuclei of tidally disrupted galaxies. The existence of genuine star clusters with stellar masses >107 M⊙ naturally leads to questions about the upper mass limit of the star cluster formation process. In this work we compile a comprehensive catalogue of CSS, and reinforce the evidence that the true ancient star cluster population has a maximum mass of M⋆ ∼ 5 × 107 M⊙, corresponding to a stellar mass at birth of close to 108 M⊙. We then discuss several physical and statistical mechanisms potentially responsible for creating this limiting mass.

scholarly journals The main sequence of star-forming galaxies – II. A non-evolving slope at the high-mass end

2019 ◽  
Vol 490 (4) ◽  
pp. 5285-5299 ◽  
Author(s):  
P Popesso ◽  
L Morselli ◽  
A Concas ◽  
C Schreiber ◽  
G Rodighiero ◽  
...  
Keyword(s):  
Main Sequence ◽  
Formation Rate ◽  
Selection Effect ◽  
Far Infrared ◽  
Stellar Mass ◽  
High Mass ◽  
Star Forming ◽  
Infrared Surveys ◽  
Local Relation ◽  
Stellar Masses

ABSTRACT By using the deepest available mid- and far-infrared surveys in the CANDELS, GOODS, and COSMOS fields we study the evolution of the main sequence (MS) of star-forming galaxies (SFGs) from z ∼ 0 to ∼ 2.5 at stellar masses larger than 1010 M⊙. The MS slope and scatter are consistent with a rescaled version of the local relation and distribution, shifted at higher values of star formation rate (SFR) according to ∝ (1 + $z$)3.2. The relation exhibits a bending at the high-mass end and a slightly increasing scatter as a function of the stellar mass. We show that the previously reported evolution of the MS slope, in the considered mass and redshift range, is due to a selection effect. The distribution of galaxies in the MS region at fixed stellar mass is well represented by a single lognormal distribution at all redshifts and masses, with starburst galaxies occupying the tail at high SFR.

scholarly journals Early-type galaxy density profiles from IllustrisTNG – I. Galaxy correlations and the impact of baryons

2019 ◽  
Vol 491 (4) ◽  
pp. 5188-5215 ◽  
Author(s):  
Yunchong Wang ◽  
Mark Vogelsberger ◽  
Dandan Xu ◽  
Shude Mao ◽  
Volker Springel ◽  
...  
Keyword(s):  
Dark Matter ◽  
Stellar Mass ◽  
High Mass ◽  
Total Power ◽  
Total Density ◽  
Early Type ◽  
Density Profiles ◽  
Low Mass ◽  
Stellar Masses ◽  
The Impact

ABSTRACT We explore the isothermal total density profiles of early-type galaxies (ETGs) in the IllustrisTNG simulation. For the selected 559 ETGs at z = 0 with stellar masses $10^{10.7}\, \mathrm{M}_{\odot } \leqslant M_{\ast } \leqslant 10^{11.9}\, \mathrm{M}_{\odot }$, the total power-law slope has a mean of 〈γ′〉 = 2.011 ± 0.007 and a scatter of $\sigma _{\gamma ^{\prime }} = 0.171$ over the radial range 0.4–4 times the stellar half-mass radius. Several correlations between γ′ and galactic properties including stellar mass, effective radius, stellar surface density, central velocity dispersion, central dark matter fraction, and in situ-formed stellar mass ratio are compared to observations and other simulations, revealing that IllustrisTNG reproduces many correlation trends, and in particular, γ′ is almost constant with redshift below z = 2. Through analysing IllustrisTNG model variations, we show that black hole kinetic winds are crucial to lowering γ′ and matching observed galaxy correlations. The effects of stellar winds on γ′ are subdominant compared to active galactic nucleus (AGN) feedback, and differ due to the presence of AGN feedback from previous works. The density profiles of the ETG dark matter haloes are well described by steeper than NFW profiles, and they are steeper in the full physics (FP) run than their counterparts in the dark matter-only (DMO) run. Their inner density slopes anticorrelate (remain constant) with the halo mass in the FP (DMO) run, and anticorrelate with the halo concentration parameter c200 in both the types of runs. The dark matter haloes of low-mass ETGs are contracted whereas high-mass ETGs are expanded, suggesting that variations in the total density profile occur through the different halo responses to baryons.

scholarly journals Metallicity gradients in small and nearby spiral galaxies

2019 ◽  
Vol 488 (3) ◽  
pp. 3826-3843 ◽  
Author(s):  
Fabio Bresolin
Keyword(s):  
Galaxy Evolution ◽  
Spiral Galaxies ◽  
Stellar Mass ◽  
H Ii Regions ◽  
Spatially Resolved ◽  
Irregular Galaxies ◽  
Low Mass ◽  
The Mean ◽  
Stellar Masses ◽  
Scale Length

ABSTRACT Spectra of H ii regions obtained with Gemini/GMOS are used to derive the radial metallicity gradients of four small, low-mass spiral galaxies. The analysis of the outer disc of one of them, NGC 1058, uncovers the characteristic flattening found in similar extended disc galaxies. After combining these data with published long-slit observations of nearby spiral galaxies, no evidence for a dependence of the disc scale length-normalized metallicity gradients with stellar mass is found, down to log (M⋆/M⊙) ∼ 8.5. The abundance gradients derived from these observations are compared to predictions from recent cosmological simulations of galaxy evolution, finding that in several cases the simulations fail to reproduce the mean steepening of the gradients, expressed in dex kpc−1, with decreasing stellar mass for present-day galaxies, or do not extend to sufficiently small stellar masses for a meaningful comparison. The mean steepening of the abundance gradients (in dex kpc−1) with decreasing disc scale length is in qualitative agreement with predictions from the inside-out model of Boissier & Prantzos, although the predicted slopes are systematically steeper than observed. This indicates the necessity of including processes such as outflows and radial mixing in similar models of galactic chemical evolution. Published spatially resolved metallicity and photometric data of dwarf irregular galaxies suggest that significant, but transitory, metallicity gradients can develop for systems that have experienced recent (t < 100 Myr) enhanced star formation in their inner discs.

scholarly journals The abundance of satellites around Milky Way- and M31-like galaxies with the TNG50 simulation: a matter of diversity

2021 ◽  
Vol 507 (3) ◽  
pp. 4211-4240 ◽  
Author(s):  
Christoph Engler ◽  
Annalisa Pillepich ◽  
Anna Pasquali ◽  
Dylan Nelson ◽  
Vicente Rodriguez-Gomez ◽  
...  
Keyword(s):  
Milky Way ◽  
Satellite System ◽  
Stellar Mass ◽  
Magellanic Cloud ◽  
High Mass ◽  
Small Magellanic Cloud ◽  
Host Galaxies ◽  
Individual Host ◽  
Stellar Masses ◽  
K Band

ABSTRACT We study the abundance of satellite galaxies around 198 Milky Way- (MW) and M31-like hosts in TNG50, the final installment in the IllustrisTNG suite of cosmological magnetohydrodynamical simulations. MW/M31-like analogues are defined as discy galaxies with stellar masses of $M_* = 10^{10.5 - 11.2}~\rm {M}_\odot$ in relative isolation at z = 0. By defining satellites as galaxies with $M_* \ge 5\times 10^{6}~\rm {M}_\odot$ within $300~\rm {kpc}$ (3D) of their host, we find a remarkable level of diversity and host-to-host scatter across individual host galaxies. The median TNG50 MW/M31-like galaxy hosts a total of $5^{+6}_{-3}$ satellites with $M_* \ge 8 \times 10^6~\rm {M}_\odot$, reaching up to $M_* \sim 10^{8.5^{+0.9}_{-1.1}}~\rm {M}_\odot$. Even at a fixed host halo mass of $10^{12}~\rm {M}_\odot$, the total number of satellites ranges between 0 and 11. The abundance of subhaloes with $M_\rm {dyn} \ge 5 \times 10^7~\rm {M}_\odot$ is larger by a factor of more than 10. The number of all satellites (subhaloes) ever accreted is larger by a factor of 4–5 (3–5) than those surviving to z = 0. Hosts with larger galaxy stellar mass, brighter K-band luminosity, more recent halo assembly, and – most significantly – larger total halo mass typically have a larger number of surviving satellites. The satellite abundances around TNG50 MW/M31-like galaxies are consistent with those of mass-matched hosts from observational surveys (e.g. SAGA) and previous simulations (e.g. Latte). While the observed MW satellite system falls within the TNG50 scatter across all stellar masses considered, M31 is slightly more satellite-rich than our 1σ scatter but well consistent with the high-mass end of the TNG50 sample. We find a handful of systems with both a Large and a Small Magellanic Cloud-like satellite. There is no missing satellites problem according to TNG50.

scholarly journals Quenching of Star-formation Activity of High-redshift Galaxies in Clusters and Field

2015 ◽  
Vol 11 (S319) ◽  
pp. 28-28
Author(s):  
Seong-Kook Lee ◽  
Myungshin Im ◽  
Jae-Woo Kim ◽  
Jennifer Lotz ◽  
Conor McPartland ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
High Redshift ◽  
Galaxy Cluster ◽  
Stellar Mass ◽  
High Mass ◽  
Photometric Redshifts ◽  
Redshift Range ◽  
Star Formation In Galaxies ◽  
Stellar Masses

AbstractAt local, galaxy properties are well known to be clearly different in different environments. However, it is still an open question how this environment-dependent trend has been shaped. We present the results of our investigation about the evolution of star-formation properties of galaxies over a wide redshift range, from z ~ 2 to z ~ 0.5, focusing its dependence on their stellar mass and environment (Lee et al. 2015). In the UKIDSS/UDS region, covering ~2800 square arcmin, we estimated photometric redshifts and stellar population properties, such as stellar masses and star-formation rates, using the deep optical and near-infrared data available in this field. Then, we identified galaxy cluster candidates within the given redshift range. Through the analysis and comparison of star-formation (SF) properties of galaxies in clusters and in field, we found interesting results regarding the evolution of SF properties of galaxies: (1) regardless of redshifts, stellar mass is a key parameter controlling quenching of star formation in galaxies; (2) At z < 1, environmental effects become important at quenching star formation regardless of stellar mass of galaxies; and (3) However, the result of the environmental quenching is prominent only for low mass galaxies (M* < 1010 M⊙) since the star formation in most of high mass galaxies are already quenched at z > 1.

scholarly journals VIS3COS

2020 ◽  
Vol 633 ◽  
pp. A70 ◽  
Author(s):  
Ana Paulino-Afonso ◽  
David Sobral ◽  
Behnam Darvish ◽  
Bruno Ribeiro ◽  
Ian Smail ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Formation Rate ◽  
Local Environment ◽  
Stellar Mass ◽  
Massive Galaxies ◽  
Stellar Masses ◽  
Star Formation Histories ◽  
Intermediate Density

We present spectroscopic observations of 466 galaxies in and around a superstructure at z ∼ 0.84 targeted by the VIMOS Spectroscopic Survey of a Supercluster in the COSMOS field (VIS3COS). We use [OII]λ3727, Hδ, and Dn4000 to trace recent, medium-, and long-term star formation histories and investigate the effect of stellar mass and local environment on them. By studying trends in individual and composite galaxy spectra, we find that stellar mass and environment play a role in the observed galactic properties. Galaxies with low stellar mass (10 <  log10(M⋆/M⊙) < 10.5) in the field show the strongest Hδ absorption. Similarly, the massive population (log10(M⋆/M⊙) > 11) shows an increase in Hδ absorption strengths in intermediate-density environments (e.g. filaments). Galaxies with intermediate stellar mass (10.5 <  log10(M⋆/M⊙) < 11) have similar Hδ absorption profiles in all environments, but show an indication of enhanced [OII] emission in intermediate-density environments. This indicates that field galaxies with low stellar mass and filament galaxies with high stellar mass are more likely to have experienced a recent burst of star formation, while galaxies of the intermediate stellar-mass show an increase of star formation at filament-like densities. We also find that the median [OII] equivalent width (|EW[OII]|) decreases from 27 ± 2 Å to 2.0+0.5−0.4 Å and Dn4000 increases from 1.09 ± 0.01 to 1.56 ± 0.03 with increasing stellar mass (from ∼109.25 to ∼1011.35 M⊙). For the dependence on the environment, we find that at fixed stellar mass, |EW[OII]| is tentatively lower in environments with higher density. We find for Dn4000 that the increase with stellar mass is sharper in denser environments, which indicates that these environments may accelerate galaxy evolution. Moreover, we find higher Dn4000 values in denser environments at fixed stellar mass, suggesting that galaxies are on average older and/or more metal rich in these dense environments. This set of tracers depicts a scenario where the most massive galaxies have, on average, the lowest specific star formation rates and the oldest stellar populations (age ≳ 1 Gyr, showing a mass-downsizing effect). We also hypothesize that the observed increase in star formation (higher EW[OII]|, higher specific star formation rate) at intermediate densities may lead to quenching because we find that the quenched fraction increases sharply from the filament to cluster-like regions at similar stellar masses.

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