scholarly journals SDSS IV MaNGA: Metallicity and ionisation parameter in local star-forming galaxies from Bayesian fitting to photoionisation models

2020 ◽  
Vol 636 ◽  
pp. A42 ◽  
Author(s):  
M. Mingozzi ◽  
F. Belfiore ◽  
G. Cresci ◽  
K. Bundy ◽  
M. Bershady ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Theoretical Work ◽  
Universal Relation ◽  
Star Forming ◽  
Spatially Resolved ◽  
Integral Field Spectroscopy ◽  
Radial Profiles ◽  
Central Regions ◽  
Optical Line ◽  
Low Mass

We measured gas-phase metallicity, ionisation parameter, and dust extinction for a representative sample of 1795 local star-forming galaxies using integral field spectroscopy from the SDSS-IV MaNGA survey. We self-consistently derive these quantities by comparing observed line fluxes with photoionisation models using a Bayesian framework. We also present the first comprehensive study of the [S III]λλ9069,9532 nebular lines, which have long been predicted to be ideal tracers of the ionisation parameter. However, we find that current photoionisation model predictions substantially over-predict the intensity of the [S III] lines, while broadly reproducing other observed optical line ratios. We discuss how to nonetheless make use of the information provided by the [S III] lines by setting a prior on the ionisation parameter. Following this approach, we derive spatially resolved maps and radial profiles of metallicity and ionisation parameter. The metallicity radial profiles derived are comparable with previous works, with metallicity declining toward the outer parts and showing a flattening in the central regions. This is in agreement with infall models of galaxy formation, which predict that spiral discs build up through accretion of material, leading to an inside-out growth. On the other hand, ionisation parameter radial profiles are flat for low-mass galaxies, while their slope becomes positive as galaxy mass increases. However, the ionisation parameter maps we obtain are clumpy, especially for low-mass galaxies. The ionisation parameter is tightly correlated with the equivalent width of Hα [EW(Hα)], following a nearly universal relation, which we attribute to the change of the spectral shape of ionising sources due to ageing of H II regions. We derive a positive correlation between ionisation parameter and metallicity at fixed EW(Hα), in disagreement with previous theoretical work that predict an anti-correlation.

scholarly journals SDSS-IV MaNGA: environmental dependence of gas metallicity gradients in local star-forming galaxies

2019 ◽  
Vol 489 (1) ◽  
pp. 1436-1450 ◽  
Author(s):  
Jianhui Lian ◽  
Daniel Thomas ◽  
Cheng Li ◽  
Zheng Zheng ◽  
Claudia Maraston ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Star Forming ◽  
Spatially Resolved ◽  
The Galaxy ◽  
Low Mass ◽  
Satellite Galaxies ◽  
Galaxy Environment ◽  
Gas Accretion

ABSTRACT Within the standard model of hierarchical galaxy formation in a Λ cold dark matter universe, the environment of galaxies is expected to play a key role in driving galaxy formation and evolution. In this paper, we investigate whether and how the gas metallicity and the star formation surface density (ΣSFR) depend on galaxy environment. To this end, we analyse a sample of 1162 local, star-forming galaxies from the galaxy survey Mapping Nearby Galaxies at APO (MaNGA). Generally, both parameters do not show any significant dependence on environment. However, in agreement with previous studies, we find that low-mass satellite galaxies are an exception to this rule. The gas metallicity in these objects increases while their ΣSFR decreases slightly with environmental density. The present analysis of MaNGA data allows us to extend this to spatially resolved properties. Our study reveals that the gas metallicity gradients of low-mass satellites flatten and their ΣSFR gradients steepen with increasing environmental density. By extensively exploring a chemical evolution model, we identify two scenarios that are able to explain this pattern: metal-enriched gas accretion or pristine gas inflow with varying accretion time-scales. The latter scenario better matches the observed ΣSFR gradients, and is therefore our preferred solution. In this model, a shorter gas accretion time-scale at larger radii is required. This suggests that ‘outside–in quenching’ governs the star formation processes of low-mass satellite galaxies in dense environments.

scholarly journals The origin of X-ray coronae around simulated disc galaxies

2021 ◽  
Vol 502 (2) ◽  
pp. 2934-2951
Author(s):  
Ashley J Kelly ◽  
Adrian Jenkins ◽  
Carlos S Frenk
Keyword(s):  
Galaxy Formation ◽  
Scaling Law ◽  
X Ray ◽  
Massive Galaxies ◽  
Star Forming ◽  
Hot Gas ◽  
Dark Matter Mass ◽  
Central Regions ◽  
Low Mass ◽  
Low X

ABSTRACT The existence of hot, accreted gaseous coronae around massive galaxies is a long-standing central prediction of galaxy formation models in the ΛCDM cosmology. While observations now confirm that extraplanar hot gas is present around late-type galaxies, the origin of the gas is uncertain with suggestions that galactic feedback could be the dominant source of energy powering the emission. We investigate the origin and X-ray properties of the hot gas that surrounds galaxies of halo mass, $(10^{11}\!-\!10^{14}) \, \mathrm{M}_\odot$, in the cosmological hydrodynamical eagle simulations. We find that the central X-ray emission, ≤0.10Rvir, of haloes of mass $\le 10^{13} \, \mathrm{M}_\odot$ originates from gas heated by supernovae (SNe). However, beyond this region, a quasi-hydrostatic, accreted atmosphere dominates the X-ray emission in haloes of mass $\ge 10^{12} \, \mathrm{M}_\odot$. We predict that a dependence on halo mass of the hot gas to dark matter mass fraction can significantly change the slope of the LX–Mvir relation (which is typically assumed to be 4/3 for clusters) and we derive the scaling law appropriate to this case. As the gas fraction in haloes increases with halo mass, we find a steeper slope for the LX–Mvir in lower mass haloes, $\le 10^{14} \, \mathrm{M}_\odot$. This varying gas fraction is driven by active galactic nuclei feedback. We also identify the physical origin of the so-called ‘missing feedback’ problem, the apparently low X-ray luminosities observed from high star-forming, low-mass galaxies. This is explained by the ejection of SNe-heated gas from the central regions of the halo.

scholarly journals Extended star-forming regions within galaxies in a dense proto-cluster core at z = 2.53†

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Tomoko L Suzuki ◽  
Yosuke Minowa ◽  
Yusei Koyama ◽  
Tadayuki Kodama ◽  
Masao Hayashi ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Structural Evolution ◽  
Cluster Core ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Star Formation Activity ◽  
Radial Profiles ◽  
Structural Growth ◽  
The One

Abstract At z ∼ 2, star formation activity is thought to be high even in high-density environments such as galaxy clusters and proto-clusters. One of the critical but outstanding issues is if the structural growth of star-forming galaxies can differ depending on their surrounding environments. In order to investigate how galaxies grow their structures and what physical processes are involved in the evolution of galaxies, one requires spatially resolved images of not only stellar components but also star-forming regions within galaxies. We conducted (Adaptive Optics) AO-assisted imaging observations for star-forming galaxies in a dense proto-cluster core at z = 2.53 with IRCS and AO188 mounted on the Subaru Telescope. A combination of AO and narrow-band filters allows us to obtain resolved maps of Hα-emitting regions with an angular resolution of ${0{^{\prime\prime}_{.}}1}$–${0{^{\prime\prime}_{.}}2}$, which corresponds to ∼1 kpc at z ∼ 2.5. Based on stacking analyses, we compare radial profiles of star-forming regions and stellar components and find that the star-forming region of a sub-sample with log (M*/$M_\odot$) ∼ 10–11 is more extended than the stellar component, indicating the inside-out growth of the structure. This trend is similar to the one for star-forming galaxies in general fields at z = 2–2.5 obtained with the same observational technique. Our results suggest that the structural evolution of star-forming galaxies at z = 2–2.5 is mainly driven by internal secular processes irrespective of surrounding environments.

scholarly journals Molecules in Action: Extragalactic ISM at high resolution

2015 ◽  
Vol 11 (S315) ◽  
pp. 42-48
Author(s):  
Sergio Martín
Keyword(s):  
Observational Studies ◽  
Physical Structure ◽  
Physical Processes ◽  
Limited Sample ◽  
Star Forming ◽  
Spatially Resolved ◽  
Central Regions ◽  
External Galaxies ◽  
Molecular Tracers ◽  
Nuclear Regions

AbstractDuring the last two decade, observations have shown the potential of molecular tracers to get insights into the physical processes taking place in the central regions of active galaxies. However, observations were severely limited by both sensitivity and resolution. This resulted also in a limited sample of bright enough galaxies where molecular species other than carbon monoxide could be observed. Current instruments like ALMA and the upcoming NOEMA are already changing our view of the extragalactic ISM molecular observations. In fact, it is now possible to study the physical properties of individual spatially resolved star forming GMCs in external galaxies, as well as resolving the physical structure of the ISM in the surroundings of AGNs at scales of a few parsecs. Here I quickly review some of the most recent observational studies in the nuclear regions of galaxies which are setting new standards in the ways we can study the extragalactic ISM properties.

scholarly journals Formation and Evolution of Nucleated Galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 172-174
Author(s):  
Kenji Bekki
Keyword(s):  
Galaxy Formation ◽  
Globular Clusters ◽  
High Redshift ◽  
Galaxy Mergers ◽  
Galaxy Formation And Evolution ◽  
Central Regions ◽  
Low Mass ◽  
Formation And Evolution ◽  
Nuclear Structures ◽  
High Redshift Universe

AbstractWe discuss how stellar galactic nuclei (SGN) form and evolve during galaxy formation and evolution based on chemodynamical simulations on the central regions (1-1000 pc) of galaxies. Our simulations demonstrate that dissipative formation of SGN through rapid transfer of gas into the central 10 pc of galaxies is more consistent with recent observations of SGN than dissipationless formation of SGN through merging of globular clusters (GCs). Nuclear structures in the remnants of major galaxy mergers between low-mass, nucleated spirals are found to depend strongly on the mass-ratio of massive black holes (MBHs) to SGN in spirals in the sense that the remnants have more distinct SGN in the mergers with the smaller MBH-to-SGN-mass-ratios. During the destruction of low-mass, nucleated galaxies by strong tidal fields of giant galaxies, SGN can remain intact. The stripped SGN can be observed as bright GCs around the giant galaxies. The color-magnitude relation of metal-poor GCs (referred to as “the blue tilt”) recently discovered for bright galaxies is similar to that of SGN, which suggests that the origin of the blue tilt is closely associated with the formation processes of SGN of gas-rich, low-mass dwarfs in the high redshift universe.

scholarly journals SDSS-IV MaNGA: spatially resolved dust attenuation in spiral galaxies

2020 ◽  
Vol 495 (2) ◽  
pp. 2305-2320
Author(s):  
Michael J Greener ◽  
Alfonso Aragón-Salamanca ◽  
Michael R Merrifield ◽  
Thomas G Peterken ◽  
Amelia Fraser-McKelvie ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Formation Rate ◽  
Stellar Populations ◽  
High Concentration ◽  
Full Spectrum ◽  
Star Forming ◽  
Spatially Resolved ◽  
Radial Profiles ◽  
Dust Attenuation

ABSTRACT Dust attenuation in star-forming spiral galaxies affects stars and gas in different ways due to local variations in dust geometry. We present spatially resolved measurements of dust attenuation for a sample of 232 such star-forming spiral galaxies, derived from spectra acquired by the SDSS-IV MaNGA survey. The dust attenuation affecting the stellar populations of these galaxies (obtained using full spectrum stellar population fitting methods) is compared with the dust attenuation in the gas (derived from the Balmer decrement). Both of these attenuation measures increase for local regions of galaxies with higher star formation rates; the dust attenuation affecting the stellar populations increases more so than the dust attenuation in the gas, causing the ratio of the dust attenuation affecting the stellar populations to the dust attenuation in the gas to decrease for local regions of galaxies with higher star formation rate densities. No systematic difference is discernible in any of these dust attenuation quantities between the spiral arm and interarm regions of the galaxies. While both the dust attenuation in the gas and the dust attenuation affecting the stellar populations decrease with galactocentric radius, the ratio of the two quantities does not vary with radius. This ratio does, however, decrease systematically as the stellar mass of the galaxy increases. Analysis of the radial profiles of the two dust attenuation measures suggests that there is a disproportionately high concentration of birth clouds (incorporating gas, young stars, and clumpy dust) nearer to the centres of star-forming spiral 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 Resolved Spectroscopy of Gravitationally Lensed Galaxies at z≃2

2014 ◽  
Vol 10 (S309) ◽  
pp. 247-250
Author(s):  
Tucker Jones
Keyword(s):  
Gas Phase ◽  
Gravitational Lensing ◽  
Gravitational Interaction ◽  
Interstellar Gas ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Integral Field Spectroscopy ◽  
Isolated Galaxies ◽  
Spatially Resolved Spectroscopy

AbstractSpatially resolved spectroscopy is even more powerful when combined with magnification by gravitational lensing. I discuss observations of lensed galaxies at z≃2 with spatial resolution reaching 100 parsecs. Near-IR integral field spectroscopy reveals the kinematics, distribution and physical properties of star forming regions, and gas-phase metallicity gradients. Roughly two thirds of observed galaxies are isolated systems with coherent velocity fields, large velocity dispersion, multiple giant star-forming regions, and negative gas-phase metallicity gradients, suggestive of inside-out growth in gravitationally unstable disks. The remainder are undergoing mergers and have shallower metallicity gradients, indicating mixing of the interstellar gas via gravitational interaction. The metallicity gradients in isolated galaxies are consistent with simulations using standard feedback prescriptions, whereas simulations with enhanced feedback predict shallower gradients. These measurements therefore constrain the growth of galaxies from mergers and star formation as well as the regulatory feedback.

scholarly journals How do central and satellite galaxies quench? – Insights from spatially resolved spectroscopy in the MaNGA survey

2020 ◽  
Vol 499 (1) ◽  
pp. 230-268 ◽  
Author(s):  
Asa F L Bluck ◽  
Roberto Maiolino ◽  
Joanna M Piotrowska ◽  
James Trussler ◽  
Sara L Ellison ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Environmental Parameters ◽  
Single Parameter ◽  
High Mass ◽  
Star Forming ◽  
Spatially Resolved ◽  
Radial Profiles ◽  
Satellite Galaxies ◽  
Spatially Resolved Spectroscopy

ABSTRACT 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 (ΣSFR), derived in Bluck et al. (2020), to compute the distance at which each spaxel resides from the resolved star forming main sequence (ΣSFR − Σ* relation): ΔΣSFR. We study galaxy radial profiles in ΔΣSFR, and luminosity weighted stellar age (AgeL), split by a variety of intrinsic and environmental parameters. Via several statistical analyses, we establish that the quenching of central galaxies is governed by intrinsic parameters, with central velocity dispersion (σc) being the most important single parameter. High mass satellites quench in a very similar manner to centrals. Conversely, low mass satellite quenching is governed primarily by environmental parameters, with local galaxy overdensity (δ5) being the most important single parameter. Utilizing the empirical MBH − σc relation, we estimate that quenching via AGN feedback must occur at $M_{\rm BH} \ge 10^{6.5-7.5} \, \mathrm{M}_{\odot }$, and is marked by steeply rising ΔΣSFR radial profiles in the green valley, indicating ‘inside-out’ quenching. On the other hand, environmental quenching occurs at overdensities of 10–30 times the average galaxy density at z∼ 0.1, and is marked by steeply declining ΔΣSFR profiles, indicating ‘outside-in’ quenching. Finally, through an analysis of stellar metallicities, we conclude that both intrinsic and environmental quenching must incorporate significant starvation of gas supply.

scholarly journals High-Redshift Radio Galaxies

1995 ◽  
Vol 10 ◽  
pp. 543-546
Author(s):  
George Miley
Keyword(s):  
Galaxy Formation ◽  
High Redshift ◽  
Line Emission ◽  
Optical Emission ◽  
Delta Function ◽  
Radio Galaxies ◽  
Radio Continuum ◽  
Spatially Resolved ◽  
A Value ◽  
Optical Line

Radio galaxies are unique cosmological probes. As with radio-loud quasars, the presence of luminous radio continuum and optical line emission enable radio galaxies to be observed and recognized at large distances, up to z = 4.2. However, unlike the situation for most quasars, their optical emission can be spatially resolved from the ground and studied in detail.Progress in detecting distant radio galaxies has been rapid in recent years due to the use of CCDs and the exploitation of new selection criteria. Now, more than 60 radio galaxies are known with z > 2. More than half of these have been found by our group by concentrating on radio sources with the steepest spectra, most of these in a “Key Programme” of the European Southern Observatory. Although several people contributed to this Key Programme, most of the work was done by Huub Röttgering, who presented his Ph.D thesis in January and Rob van Ojik, who succeededhim. Redshifts of 1.5 to 4 correspond to a time when the Universe was 10% -20% of its present age. This was a crucial period in history when galaxy formation must have been rampant. It corresponds to the AGN era, a two-billion year “delta function” in the population evolution of luminous quasars and radio galaxies, when their space-density rose to a value several hundred times larger than the present density before the species mysteriously and suddenly became almost extinct.

Sign in / Sign up

Export Citation Format

Share Document