scholarly journals The atomic hydrogen content of galaxies as a function of group-centric radius

2021 ◽  
Vol 507 (4) ◽  
pp. 5580-5591 ◽  
Author(s):  
Wenkai Hu ◽  
Luca Cortese ◽  
Lister Staveley-Smith ◽  
Barbara Catinella ◽  
Garima Chauhan ◽  
...  
Keyword(s):  
Hydrogen Content ◽  
Atomic Hydrogen ◽  
Local Density ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
High Mass ◽  
Galaxy Groups ◽  
Isolated Galaxies ◽  
Nearby Galaxies ◽  
Stellar Masses

ABSTRACT We apply a spectral stacking technique to Westerbork Synthesis Radio Telescope observations to measure the neutral atomic hydrogen content (H i) of nearby galaxies in and around galaxy groups at z < 0.11. Our sample includes 577 optically selected galaxies (120 isolated galaxies and 457 satellites) covering stellar masses between 1010 and 1011.5 M⊙, cross-matched with Yang’s group catalogue, with angular and redshift positions from the Sloan Digital Sky Survey. We find that the satellites in the centres of groups have lower H i masses at fixed stellar mass and morphology (characterized by the inverse concentration index) relative to those at larger radii. These trends persist for satellites in both high-mass ($M_{\rm halo} \gt 10^{13.5}\, h^{-1}\, \mathrm{M}_{\odot }$) and low-mass ($M_{\rm halo} \leqslant 10^{13.5}\, h^{-1}\, \mathrm{M}_{\odot }$) groups, but disappear if we only consider group members in low local density (Σ < 5 gal Mpc−2) environments. Similar trends are found for the specific star formation rate. Interestingly, we find that the radial trends of decreasing H i mass with decreasing group-centric radius extend beyond the group virial radius, as isolated galaxies close to larger groups lack H i compared with those located more than ∼3.0 R180 away from the centre of their nearest group. We also measure these trends in the late-type subsample and obtain similar results. Our results suggest that the H i reservoir of galaxies can be affected before galaxies become group satellites, indicating the existence of pre-processing in the infalling isolated galaxies.

scholarly journals Gas Flows in Galaxies: the Relative Importance of Mergers and Bars.

2010 ◽  
Vol 6 (S277) ◽  
pp. 178-181
Author(s):  
Sara L. Ellison ◽  
David R. Patton ◽  
Preethi Nair ◽  
Luc Simard ◽  
J. Trevor Mendel ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Formation Rate ◽  
Control Sample ◽  
Central Star ◽  
Sloan Digital Sky Survey ◽  
Galaxy Interactions ◽  
Barred Galaxies ◽  
Isolated Galaxies ◽  
Stellar Masses

AbstractGalaxy-galaxy interactions and large scale galaxy bars are usually considered as the two main mechanisms for driving gas to the centres of galaxies. By using large samples of galaxy pairs and visually classified bars from the Sloan Digital Sky Survey (SDSS), we compare the relative efficiency of gas inflows from these two processes. We use two indicators of gas inflow: star formation rate (SFR) and gas phase metallicity, which are both measured relative to control samples. Whereas the metallicity of galaxy pairs is suppressed relative to its control sample of isolated galaxies, galaxies with bars are metal-rich for their stellar mass by 0.06 dex over all stellar masses. The SFRs of both the close galaxy pairs and the barred galaxies are enhanced by ~60%, but in the bars the enhancement is only seen at stellar masses M∗ > 1010 M⊙. Taking into account the relative frequency of bars and pairs, we estimate that at least three times more central star formation is triggered by bars than by interactions.

scholarly journals The dependence of mass and environment on the secular processes of AGNs in terms of morphology, colour, and specific star-formation rate

2018 ◽  
Vol 620 ◽  
pp. A113 ◽  
Author(s):  
M. Argudo-Fernández ◽  
I. Lacerna ◽  
S. Duarte Puertas
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
Stellar Mass ◽  
High Mass ◽  
Late Type ◽  
Star Forming ◽  
Isolated Galaxies

Context. Galaxy mass and environment play a major role in the evolution of galaxies. In the transition from star-forming to quenched galaxies, active galactic nuclei (AGNs) also have a principal action therein. However, the connections between these three actors are still uncertain. Aims. In this work we investigate the effects of stellar mass and the large-scale structure (LSS) environment on the fraction of optical nuclear activity in a population of isolated galaxies, where AGN would not be triggered by recent galaxy interactions or mergers. Methods. As a continuation of a previous work, we focus on isolated galaxies to study the effect of stellar mass and the LSS in terms of morphology (early- and late-type), colour (red and blue), and specific star-formation rate (quenched and star-forming). To explore where AGN activity is affected by the LSS, we separate galaxies into two groups, of low- and high mass, respectively, and use the tidal strength parameter to quantify the effects. Results. We found that AGN is strongly affected by stellar mass in “active” galaxies (namely late-type, blue, and star-forming), but that mass has no influence on “quiescent” galaxies (namely early-type, red, and quenched), at least for masses down to 1010 M⊙. In relation to the LSS, we found an increase in the fraction of star-forming nuclei galaxies with denser LSS in low-mass star-forming and red isolated galaxies. Regarding AGN, we find a clear increase in the fraction of AGNs with denser environment in quenched and red isolated galaxies, independently of the stellar mass. Conclusions. Active galactic nuclei activity appears to be “mass triggered” in active isolated galaxies. This means that AGN activity is independent of the intrinsic properties of the galaxies, but is dependent on their stellar mass. On the other hand, AGN activity appears to be “environment triggered” in quiescent isolated galaxies, where the fraction of AGNs as a function of specific star formation rate and colour increases from void regions to denser LSS, independently of stellar 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 Evolution of star formation rate–density relation over cosmic time in a simulated universe: the observed reversal reproduced

2019 ◽  
Vol 489 (1) ◽  
pp. 339-348 ◽  
Author(s):  
Ho Seong Hwang ◽  
Jihye Shin ◽  
Hyunmi Song
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Local Density ◽  
Formation Rate ◽  
Cosmic Time ◽  
Galaxy Cluster ◽  
Star Forming ◽  
Hydrodynamical Simulation ◽  
Density Relation ◽  
Stellar Masses

ABSTRACT We use the IllustrisTNG cosmological hydrodynamical simulation to study the evolution of star formation rate (SFR)–density relation over cosmic time. We construct several samples of galaxies at different redshifts from z = 2.0 to z = 0.0, which have the same comoving number density. The SFR of galaxies decreases with local density at z = 0.0, but its dependence on local density becomes weaker with redshift. At z ≳ 1.0, the SFR of galaxies increases with local density (reversal of the SFR–density relation), and its dependence becomes stronger with redshift. This change of SFR–density relation with redshift still remains even when fixing the stellar masses of galaxies. The dependence of SFR on the distance to a galaxy cluster also shows a change with redshift in a way similar to the case based on local density, but the reversal happens at a higher redshift, z ∼ 1.5, in clusters. On the other hand, the molecular gas fraction always decreases with local density regardless of redshift at z = 0.0–2.0 even though the dependence becomes weaker when we fix the stellar mass. Our study demonstrates that the observed reversal of the SFR–density relation at z ≳ 1.0 can be successfully reproduced in cosmological simulations. Our results are consistent with the idea that massive, star-forming galaxies are strongly clustered at high redshifts, forming larger structures. These galaxies then consume their gas faster than those in low-density regions through frequent interactions with other galaxies, ending up being quiescent in the local universe.

scholarly journals Exploring star formation in high-mass galaxies in the low-z universe

2018 ◽  
Author(s):  
◽  
James Runge
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Value Added ◽  
Sloan Digital Sky Survey ◽  
High Mass ◽  
Wide Field ◽  
Max Planck ◽  
Field Sample

We present a quantitative analysis of high-mass, low-z galaxies in order to investigate the 'downsizing' scenario of galaxy evolution. High-mass, low-z galaxies with ongoing star formation, antithetical to the 'downsizing' model, are identified using the 22�m data (W4 band) from the Wide-field Infrared Survey Explorer (WISE). A cluster and field sample is chosen to investigate any possible environmental effects. The cluster sample is based upon the GMBCG catalog, which contains 55,424 brightest cluster galaxies (BCGs) at 0.1 [less than or about] z [less than or about] 0.55 identified in the Sloan Digital Sky Survey (SDSS). We identify 389 W4-detected BCGs (W4BCGs) that have median SFRs of [about]50 M[symbol]/yr based upon their total IR luminosity (LIR), which is attributed to dust-enshrouded star formation. BCGs with such high SFRs are found in "cool-core" clusters and the star formation is thought to be fueled by a "cooling flow." Using Chandra X-ray data, it is shown that a subset of BCGs do reside within coolcores, but their mass deposition rates cannot account for the SFR. For comparison, a field sample is drawn from the Max-Planck Institute for Astrophysics - John Hopkins University (MPA-JHU) "value-added" SDSS DR7 catalog of spectrum measurements. A set of 1,244 high-mass, elliptical field galaxies within the same redshift range as the W4BCG catalog are identified for comparison. The median mass for the field sample is lower than the W4BCGs (Log(M/M[symbol])=10.9 and 11.2 respectively), as are their SFRs. However, the specific star formation rate (sSFR), the star formation rate per stellar mass, is comparable for both groups (Log(sSFR)[about]-9.7). This possibly reveals that there is no environmental dependence on the sSFR for these W4-detected galaxies. While a possible mechanism responsible for the SFR was identified for the W4BCGs, the process responsible for the star formation in the field sample requires further investigation.

scholarly journals Direct Effects of the Environment on AGN Triggering in SDSS Spiral Galaxies: Merger-AGN connection

2019 ◽  
Author(s):  
Minbae Kim ◽  
Yun-Young Choi ◽  
Sungsoo S Kim
Keyword(s):  
Spiral Galaxies ◽  
Local Density ◽  
Formation Rate ◽  
Absolute Magnitude ◽  
Central Star ◽  
Sloan Digital Sky Survey ◽  
Activity Level ◽  
Limited Sample ◽  
Star Forming ◽  
The Rich

Abstract We examine whether galaxy environments directly affect triggering nuclear activity in Sloan Digital Sky Survey (SDSS) local spiral galaxies using a volume-limited sample with the r-band absolute magnitude Mr < −19.0 and 0.02 < z < 0.055 selected from the SDSS Data Release 7. To avoid incompleteness of the central velocity dispersion σ of the volume-limited sample and to fix the black hole mass affecting AGN activity, we limit the sample to a narrow σ range of 130 < σ < 200 km s−1. We define a variety of environments as a combination of neighbour interactions and local density on a galaxy. After the central star formation rate (which is closely related to AGN activity level) is additionally restricted, the direct impact of the environment is unveiled. In the outskirts of rich clusters, red spiral galaxies show a significant excess of the AGN fraction despite the lack of central gas. We argue that they have been pre-processed before entering the rich clusters, and due to mergers or strong encounters in the in-fall region, their remaining gases efficiently lose angular momentum. Furthermore, we find many star-forming galaxies and only a few starburst-AGN composite hosts with the highest [OIII] luminosity. We claim that they are a gas-rich merger product in groups or are group galaxies in-falling into clusters, indicating that many AGN signatures may be obscured during the merger events.

scholarly journals H i study of isolated and paired galaxies: the MIR SFR-M⋆ sequence

2020 ◽  
Vol 499 (3) ◽  
pp. 3193-3213
Author(s):  
J Bok ◽  
R E Skelton ◽  
M E Cluver ◽  
T H Jarrett ◽  
M G Jones ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Wide Field ◽  
Fraction H ◽  
Isolated Galaxies ◽  
Baseline Predictor ◽  
Stellar Masses ◽  
The Impact

ABSTRACT Using mid-infrared star formation rate and stellar mass indicators in WISE (Wide-field Infrared Survey Explorer), we construct and contrast the relation between star formation rate and stellar mass for isolated and paired galaxies. Our samples comprise a selection of AMIGA (Analysis of the interstellar Medium in Isolated GAlaxies; isolated galaxies) and pairs of ALFALFA (Arecibo Legacy Fast ALFA) galaxies with H i detections such that we can examine the relationship between H i content (gas fraction, H i deficiency) and galaxy location on the main sequence (MS) in these two contrasting environments. We derive for the first time an H i scaling relation for isolated galaxies using WISE stellar masses, and thereby establish a baseline predictor of H i content that can be used to assess the impact of environment on H i content when compared with samples of galaxies in different environments. We use this updated relation to determine the H i deficiency of both our paired and isolated galaxies. Across all the quantities examined as a function of environment in this work (MS location, gas fraction, and H i deficiency), the AMIGA sample of isolated galaxies is found to have the lower dispersion: σAMIGA = 0.37 versus σPAIRS = 0.55 on the MS, σAMIGA = 0.44 versus σPAIRS = 0.54 in gas fraction, and σAMIGA = 0.28 versus σPAIRS = 0.34 in H i deficiency. We also note fewer isolated quiescent galaxies, 3 (0.6${{\ \rm per\ cent}}$), compared to 12 (2.3${{\ \rm per\ cent}}$) quiescent pair members. Our results suggest the differences in scatter measured between our samples are environment driven. Galaxies in isolation behave relatively predictably, and galaxies in more densely populated environments adopt a more stochastic behaviour, across a broad range of quantities.

scholarly journals Diffuse ionized gas and its effects on nebular metallicity estimates of star-forming galaxies

2019 ◽  
Vol 489 (4) ◽  
pp. 4721-4733 ◽  
Author(s):  
N Vale Asari ◽  
G S Couto ◽  
R Cid Fernandes ◽  
G Stasińska ◽  
A L de Amorim ◽  
...  
Keyword(s):  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Strong Line ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Stellar Masses ◽  
The Impact

ABSTRACT We investigate the impact of the diffuse ionized gas (DIG) on abundance determinations in star-forming (SF) galaxies. The DIG is characterized using the H α equivalent width (WH α). From a set of 1 409 SF galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, we calculate the fractional contribution of the DIG to several emission lines using high-S/N data from SF spaxels (instead of using noisy emission-lines in DIG-dominated spaxels). Our method is applicable to spectra with observed WH α ≳ 10 Å (which are not dominated by DIG emission). Since the DIG contribution depends on galactocentric distance, we provide DIG-correction formulae for both entire galaxies and single aperture spectra. Applying those to a sample of $\, \gt 90\, 000$ SF galaxies from the Sloan Digital Sky Survey, we find the following. (1) The effect of the DIG on strong-line abundances depends on the index used. It is negligible for the ([O iii]/H β)/([N ii]/H α) index, but reaches ∼0.1 dex at the high-metallicity end for [N ii]/H α. (2) This result is based on the ∼kpc MaNGA resolution, so the real effect of the DIG is likely greater. (3) We revisit the mass–metallicity–star formation rate (SFR) relation by correcting for the DIG contribution in both abundances and SFR. The effect of DIG removal is more prominent at higher stellar masses. Using the [N ii]/Hα index, O/H increases with SFR at high stellar mass, contrary to previous claims.

scholarly journals The OTELO survey

2020 ◽  
Vol 636 ◽  
pp. A84 ◽  
Author(s):  
Jakub Nadolny ◽  
Maritza A. Lara-López ◽  
Miguel Cerviño ◽  
Ángel Bongiovanni ◽  
Jordi Cepa ◽  
...  
Keyword(s):  
Emission Line ◽  
Dwarf Galaxy ◽  
Formation Rate ◽  
Tunable Filter ◽  
Sloan Digital Sky Survey ◽  
Minimization Method ◽  
High Resolution Data ◽  
Star Forming ◽  
Low Mass ◽  
Stellar Masses

Context. A sample of low-mass Hα emission line sources at z ∼ 0.4 was studied in the context of the mass-metallicty relation (MZR) and its possible evolution. We drew our sample from the OSIRIS Tunable Emission Line Object (OTELO) survey, which exploits the red tunable filter of OSIRIS at the Gran Telescopio Canarias to perform a blind narrow-band spectral scan in a selected field of the Extended Groth Strip. We were able to directly measure emission line fluxes and equivalent widths from the analysis of OTELO pseudo-spectra. Aims. This study aims to explore the MZR in the very low-mass regime. Our sample reaches stellar masses (M*) as low as 106.8 M⊙, where 63% of the sample have M* <  109 M⊙. We also explore the relation of the star formation rate (SFR) and specific SFR with M* and gas-phase oxygen abundances, as well as the M*-size relation and the morphological classification. Methods. The M* were estimated using synthetic rest-frame colours. Using an χ2 minimization method, we separated the contribution of [N II]λ6583 to the Hα emission lines. Using the N2 index, we separated active galactic nuclei from star-forming galaxies (SFGs) and estimated the gas metallicity. We studied the morphology of the sampled galaxies qualitatively (visually) and quantitatively (automatically) using high-resolution data from the Hubble Space Telescope-ACS. The physical size of the galaxies was derived from the morphological analysis using GALAPAGOS2/GALFIT, where we fit a single-Sérsic 2D model to each source. Results. We find no evidence for an MZR evolution from comparing our very low-mass sample with local SFGs from the Sloan Digital Sky Survey. Furthermore, the same is true for M*-size and M*-SFR relations, as we deduce from comparison with recent literature. Morphologically, our sample is mostly (63%) populated by late-type galaxies, with 13% of early-type sources. For the first time, we identify one possible candidate outlier in the MZR at z = 0.4. The stellar-mass, metallicity, colour, morphology, and SFR of this source suggest that it is compatible with a transitional dwarf galaxy.

scholarly journals GLACE survey: Galaxy activity in ZwCl0024+1652 cluster from strong optical emission lines

2020 ◽  
Vol 501 (2) ◽  
pp. 2430-2450
Author(s):  
Zeleke Beyoro-Amado ◽  
Miguel Sánchez-Portal ◽  
Ángel Bongiovanni ◽  
Mirjana Pović ◽  
Solomon B Tessema ◽  
...  
Keyword(s):  
Star Formation ◽  
Local Density ◽  
Formation Rate ◽  
Galaxy Cluster ◽  
Optical Emission ◽  
Tunable Filter ◽  
Emission Lines ◽  
High Mass ◽  
Cluster Galaxies ◽  
Emission Line Galaxies

ABSTRACT Although ZwCl0024+1652 galaxy cluster at z ∼ 0.4 has been thoroughly analysed, it lacks a comprehensive study of star formation and nuclear activity of its members. With GaLAxy Cluster Evolution (GLACE) survey, a total of 174 H α emission-line galaxies (ELGs) were detected, most of them having [N ii]. We reduced and analysed a set of [O iii] and H β tunable filter (TF) observations within GLACE survey. Using H α priors, we identified [O iii] and H β in 35 (∼20 per cent) and 59 (∼34 per cent) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [N ii]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40 per cent star-forming (SF), 55 per cent composites, and 5 per cent LINERs. Star formation rate (SFR) measured through extinction corrected H α fluxes increases with stellar mass (M*), attaining its peak at $\mathrm{\mathit{ M}}_{*}\sim 10^{9.8}\, \mathrm{M}_\odot$. We observed that the cluster centre to ∼ 1.3 Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high M*, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with M* while specific SFR (sSFR) anticorrelates with M*, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H β and/or [O iii] lines in ZwCl0024+1652 cluster.

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