scholarly journals Mapping the spatial distribution of star formation in cluster galaxies at z ~ 0.5 with the Grism Lens-Amplified Survey from Space (GLASS)

2015 ◽  
Vol 11 (A29B) ◽  
pp. 797-800
Author(s):  
Benedetta Vulcani ◽  
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Mass Density ◽  
Control Sample ◽  
Gravitational Lens ◽  
Wide Field ◽  
Surface Mass ◽  
Cluster Galaxies ◽  
Hα Emission ◽  
Stellar Masses

AbstractWe present the first study of the spatial distribution of star formation in z ~ 0.5 cluster galaxies. The analysis is based on data taken with the Wide Field Camera 3 as part of the Grism Lens-Amplified Survey from Space (GLASS). We illustrate the methodology by focusing on two clusters (MACS0717.5+3745 and MACS1423.8+2404) with different morphologies (one relaxed and one merging) and use foreground and background galaxies as field control sample. The cluster+field sample consists of 42 galaxies with stellar masses in the range 108-1011M⊙, and star formation rates in the range 1-20 M⊙yr−1. In both environments, Hα is more extended than the rest-frame UV continuum in 60% of the cases, consistent with diffuse star formation and inside out growth. The Hα emission appears more extended in cluster galaxies than in the field, pointing perhaps to ionized gas being stripped and/or star formation being enhanced at large radii. The peak of the Hα emission and that of the continuum are offset by less than 1 kpc. We investigate trends with the hot gas density as traced by the X-ray emission, and with the surface mass density as inferred from gravitational lens models and find no conclusive results. The diversity of morphologies and sizes observed in Hα illustrates the complexity of the environmental process that regulate star formation.

scholarly journals The first 62 AGN observed with SDSS-IV MaNGA – IV. Gas excitation and star formation rate distributions

2019 ◽  
Vol 486 (4) ◽  
pp. 5075-5093 ◽  
Author(s):  
Janaína C do Nascimento ◽  
Thaisa Storchi-Bergmann ◽  
Nícolas D Mallmann ◽  
Rogério Riffel ◽  
Gabriele S Ilha ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Mass Density ◽  
Formation Rate ◽  
Control Sample ◽  
The Body ◽  
Ionized Gas ◽  
Surface Mass ◽  
Line Region ◽  
The Galaxy

Abstract We present maps of the ionized gas flux distributions, excitation, star formation rate (SFR), surface mass density ΣH+, and obtain total values of SFR and ionized gas masses M for 62 active galactic nuclei (AGN) observed with SDSS-IV MaNGA and compare them with those of a control sample of 112 non-active galaxies. The most luminous AGN – with $L(\rm {[O\,{\small III}]}\lambda 5007) \ge 3.8\times 10^{40}\, \mbox{erg}\, \mbox{s}^{-1}$, and those hosted by earlier type galaxies are dominated by Seyfert excitation within 0.2 effective radius Re from the nucleus, surrounded by LINER excitation or transition regions, while the less luminous and hosted by later-type galaxies show equally frequent LINER and Seyfert excitation within $0.2\, R_\mathrm{ e}$. The extent R of the region ionized by the AGN follows the relation $R\propto \, L(\rm {[O\,{\small III}]})^{0.5}$ – as in the case of the broad-line region. The SFR distribution over the region ionized by hot stars is similar for AGN and controls, while the integrated SFR – in the range 10−3–10 M⊙ yr−1 is also similar for the late-type subsample, but higher in the AGN for 75 per cent of the early-type subsample. We thus conclude that there is no signature of AGN quenching star formation in the body of the galaxy in our sample. We also find that 66 per cent of the AGN have higher ionized gas masses M than the controls – in the range 105–3 × 107 M⊙ – while 75 per cent of the AGN have higher ΣH+ within $0.2\, R_\mathrm{ e}$ than the control galaxies.

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 Spectral synthesis of stellar populations in the 3D era: The CALIFA experience

2014 ◽  
Vol 10 (S309) ◽  
pp. 93-98
Author(s):  
R. Cid Fernandes ◽  
E. A. D. Lacerda ◽  
R. M. González Delgado ◽  
N. Vale Asari ◽  
R. García-Benito ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Spectral Synthesis ◽  
Mass Density ◽  
Formation Rate ◽  
Stellar Populations ◽  
Data Cubes ◽  
The Mean ◽  
Stellar Masses ◽  
Star Formation Histories

AbstractMethods to recover the fossil record of galaxy evolution encoded in their optical spectra have been instrumental in processing the avalanche of data from mega-surveys along the last decade, effectively transforming observed spectra onto a long and rich list of physical properties: from stellar masses and mean ages to full star formation histories. This promoted progress in our understanding of galaxies as a whole. Yet, the lack of spatial resolution introduces undesirable aperture effects, and hampers advances on the internal physics of galaxies. This is now changing with 3D surveys. The mapping of stellar populations in data-cubes allows us to figure what comes from where, unscrambling information previously available only in integrated form. This contribution uses our starlight-based analysis of 300 CALIFA galaxies to illustrate the power of spectral synthesis applied to data-cubes. The selected results highlighted here include: (a) The evolution of the mass-metallicity and mass-density-metallicity relations, as traced by the mean stellar metallicity. (b) A comparison of star formation rates obtained from Hα to those derived from full spectral fits. (c) The relation between star formation rate and dust optical depth within galaxies, which turns out to mimic the Schmidt-Kennicutt law. (d) PCA tomography experiments.

scholarly journals THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). V. EXTENT AND SPATIAL DISTRIBUTION OF STAR FORMATION INz∼ 0.5 CLUSTER GALAXIES

2015 ◽  
Vol 814 (2) ◽  
pp. 161 ◽  
Author(s):  
Benedetta Vulcani ◽  
Tommaso Treu ◽  
Kasper B. Schmidt ◽  
Bianca M. Poggianti ◽  
Alan Dressler ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Cluster Galaxies

SDSS-IV MaNGA: Testing the Metallicity Distribution across the Merging Sequence

2018 ◽  
Vol 14 (A30) ◽  
pp. 263-264
Author(s):  
Jorge K. Barrera-Ballesteros ◽  
Li-hwai Lin ◽  
Bu-Ching Hsieh ◽  
Hsi-An Pan ◽  
Sebastian Sánchez ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Robust Control ◽  
Radial Distribution ◽  
Metal Content ◽  
Control Sample ◽  
Ionized Gas ◽  
Star Forming ◽  
The Impact ◽  
Metallicity Distribution

AbstractInteractions and mergers have been known as key scenarios to enhance global star formation rates and to lower the metal content of galaxies. However, little is known on how interactions affect the spatial distribution of gas metallicities. Thanks to the SDSS-IV MaNGA survey we are able to statistically constrain the impact of interactions across the optical distributions of galaxies. In this study, we compare the radial distribution of the ionized gas metallicity from a sample of 329 interacting objects – covering different interaction stages – with a statistical robust control sample. Our results suggest that galaxies close to coalesce tend to have flat, lower metallicities than non-interacting star-forming galaxies.

scholarly journals Passive spirals and shock influenced star formation in the merging cluster A3376

2020 ◽  
Vol 496 (1) ◽  
pp. 442-455 ◽  
Author(s):  
Kshitija Kelkar ◽  
K S Dwarakanath ◽  
Bianca M Poggianti ◽  
Alessia Moretti ◽  
Rogério Monteiro-Oliveira ◽  
...  
Keyword(s):  
Star Formation ◽  
Rapid Quenching ◽  
Wide Field ◽  
Cluster Galaxies ◽  
Star Forming ◽  
M 10 ◽  
Brightest Cluster Galaxies ◽  
Central Regions ◽  
Cluster Environment ◽  
Low Mass

ABSTRACT We present a detailed analysis of star formation properties of galaxies in a nearby (z ∼ 0.046) young (∼0.6 Gyr) post-merger cluster system A3376, with a moderate merger shock front (vs ∼1630 km s−1; $\mathcal {M}$ ∼ 2) observed as symmetric radio relics. Exploiting the spectroscopic data from the wide-field OmegaWINGS survey and the associated photometric information, our investigations reveal the plausible effects of the dynamic post-merger environment differing from the high-density cluster environment experienced prior to the merging activity. The remnants of the pre-merger relaxed cluster environment are realized through the existence of passive spiral galaxies located in the central regions of the cluster between the two brightest cluster galaxies. We discover A3376 to contain a population of massive (log (M*/M⊙) > 10) blue regular star-forming spirals in regions of maximum merger shock influence but exhibiting star formation rates similar to those in relaxed clusters at similar epoch. We further discover low-mass (log (M*/M⊙) ≤ 10) late-type blue post-starburst galaxies which could either be formed as a result of rapid quenching of low-mass spirals following the shock-induced star formation or due to the intense surge in the intracluster medium pressures at the beginning of the merger. With the possibility of the merger shock affecting high- and low-mass spirals differently, our results bridge the seemingly contradictory results observed in known merging cluster systems so far and establish that different environmental effects are at play right from pre- to post-merger stages.

scholarly journals Systematic errors in strong gravitational lensing reconstructions, a numerical simulation perspective

2020 ◽  
Vol 496 (2) ◽  
pp. 1718-1729 ◽  
Author(s):  
Wolfgang Enzi ◽  
Simona Vegetti ◽  
Giulia Despali ◽  
Jen-Wei Hsueh ◽  
R Benton Metcalf
Keyword(s):  
Gravitational Lensing ◽  
Time Delays ◽  
Surface Brightness ◽  
Mass Density ◽  
Control Sample ◽  
Brightness Distribution ◽  
Gravitational Lens ◽  
Galactic Potentials ◽  
Fractional Error ◽  
Approximate Bayesian

ABSTRACT We present the analysis of a sample of 24 SLACS-like galaxy–galaxy strong gravitational lens systems with a background source and deflectors from the Illustris-1 simulation. We study the degeneracy between the complex mass distribution of the lenses, substructures, the surface brightness distribution of the sources, and the time delays. Using a novel inference framework based on Approximate Bayesian Computation, we find that for all the considered lens systems, an elliptical and cored power-law mass density distribution provides a good fit to the data. However, the presence of cores in the simulated lenses affects most reconstructions in the form of a Source Position Transformation. The latter leads to a systematic underestimation of the source sizes by 50 per cent on average, and a fractional error in H0 of around $25_{-19}^{+37}$ per cent. The analysis of a control sample of 24 lens systems, for which we have perfect knowledge about the shape of the lensing potential, leads to a fractional error on H0 of $12_{-3}^{+6}$ per cent. We find no degeneracy between complexity in the lensing potential and the inferred amount of substructures. We recover an average total projected mass fraction in substructures of fsub < 1.7–2.0 × 10−3 at the 68 per cent confidence level in agreement with zero and the fact that all substructures had been removed from the simulation. Our work highlights the need for higher resolution simulations to quantify the lensing effect of more realistic galactic potentials better, and that additional observational constraint may be required to break existing degeneracies.

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 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 Linking star formation and galaxy kinematics in the massive cluster Abell 2163

2014 ◽  
Vol 10 (S309) ◽  
pp. 330-330
Author(s):  
Veronica Menacho ◽  
Miguel Verdugo
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Structural Parameters ◽  
High Resolution Spectroscopy ◽  
Cluster Galaxies ◽  
The Galaxy ◽  
Galaxy Kinematics ◽  
Massive Halos ◽  
Fisher Relation ◽  
Stellar Masses

AbstractThe origin of the morphology-density relation is still an open question in galaxy evolution. It is most likely driven by the combination of the efficient star formation in the highest peaks of the mass distribution at high-z and the transformation by environmental processes at later times as galaxies fall into more massive halos. To gain additional insights about these processes we study the kinematics, star formation and structural properties of galaxies in Abell 2163 a very massive (~4×1015 M⊙, Holz & Perlmutter 2012) merging cluster at z = 0.2.We use high resolution spectroscopy with VLT/VIMOS to derive rotation curves and dynamical masses for galaxies that show regular kinematics. Galaxies that show irregular rotation are also analysed to study the origin of their distortion. This information is combined with stellar masses and structural parameters obtained from high quality CFHT imaging. From narrow band photometry (2.2m/WFI), centered on the redshifted Hα line, we obtain star formation rates.Although our sample is still small, field and cluster galaxies lie in a similar Tully-Fisher relation as local galaxies. Controlling by additional parameters like SFRs or bulge-to-disk ratio do not affect this result. We find however that ~50% of the cluster galaxies display irregular kinematics in contrast to what is found in the field at similar redshifts (~30%, Böhm et al.2004) and in agreement with other studies in clusters (e.g. Bösch et al.2013, Kutdemir et al.2010) which points out to additional processes operating in clusters that distort the galaxy kinematics.

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