Evidence for Mixing between ICM and Stripped ISM by the Analysis of the Gas Metallicity in the Tails of Jellyfish Galaxies

Abstract Hydrodynamical simulations show that the ram pressure stripping in galaxy clusters fosters a strong interaction between stripped interstellar medium (ISM) and the surrounding medium, with the possibility of intracluster medium (ICM) cooling into cold gas clouds. Exploiting the MUSE observation of three jellyfish galaxies from the GAs Stripping Phenomena in galaxies with MUSE (GASP) survey, we explore the gas metallicity of star-forming clumps in their gas tails. We find that the oxygen abundance of the stripped gas decreases as a function of the distance from the parent galaxy disk; the observed metallicity profiles indicate that more than 40% of the most metal-poor stripped clouds are constituted by cooled ICM, in qualitative agreement with simulations that predict mixing between the metal-rich ISM and the metal-poor ICM.

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How runaway stars boost galactic outflows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa889 ◽

2020 ◽

Vol 494 (3) ◽

pp. 3328-3341 ◽

Cited By ~ 1

Author(s):

Eric P Andersson ◽

Oscar Agertz ◽

Florent Renaud

Keyword(s):

Interstellar Medium ◽

Large Scale ◽

Ob Stars ◽

Star Forming ◽

Star Forming Regions ◽

Order Of Magnitude ◽

Hydrodynamical Simulations ◽

Scale Properties ◽

Energy And Momentum ◽

Runaway Stars

ABSTRACT Roughly 10 per cent of OB stars are kicked out of their natal clusters before ending their life as supernovae. These so-called runaway stars can travel hundreds of parsecs into the low-density interstellar medium, where momentum and energy from stellar feedback is efficiently deposited. In this work, we explore how this mechanism affects large-scale properties of the galaxy, such as outflows. To do so we use a new model that treats OB stars and their associated feedback processes on a star-by-star basis. With this model, we compare two hydrodynamical simulations of Milky Way-like galaxies, one where we include runaways, and one where we ignore them. Including runaway stars leads to twice as many supernovae explosions in regions with gas densities ranging from $10^{-5}\, \mathrm{\,cm^{-3}}$ to $10^{-3}\, \mathrm{\,cm^{-3}}$. This results in more efficient heating of the inter-arm regions, and drives strong galactic winds with mass loading factors boosted by up to one order of magnitude. These outflows produce a more massive and extended multiphase circumgalactic medium, as well as a population of dense clouds in the halo. Conversely, since less energy and momentum is released in the dense star-forming regions, the cold phase of the interstellar medium is less disturbed by feedback effects.

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Star-forming complexes in the polar ring galaxy NGC660

Open Astronomy ◽

10.1515/astro-2017-0022 ◽

2017 ◽

Vol 26 (1) ◽

Cited By ~ 3

Author(s):

Ksenia I. Smirnova ◽

Dmitri S. Wiebe ◽

Alexei V. Moiseev

Keyword(s):

Star Formation ◽

Interstellar Medium ◽

Star Forming ◽

Polar Ring ◽

Star Forming Regions ◽

Disk Star ◽

Dust Mass ◽

The Galaxy ◽

Galaxy Disk

AbstractGalaxies with polar rings consist of two subsystems, a disk and a ring, which rotate almost in orthogonal planes. In this paper, we analyze the parameters characterizing the composition of the interstellar medium and star formation in star-forming complexes belonging to polar ring galaxy NGC660. We show that star-forming regions in the ring of the galaxy are distinctly different from those in the galaxy disk. They possess substantially lower infrared luminosities, which is indicative of less dust mass in these regions than in a typical disk star-forming region. UV and Hα luminosities also appear to be lower in the ring, which is likely a consequence of its relatively recent formation.

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GASP XXXV: Characteristics of the Diffuse Ionised Gas in Gas-stripped Galaxies

The Astrophysical Journal ◽

10.3847/1538-4357/ac230e ◽

2021 ◽

Vol 922 (2) ◽

pp. 131

Author(s):

Neven Tomičić ◽

Benedetta Vulcani ◽

Bianca M. Poggianti ◽

Ariel Werle ◽

Ancla Müller ◽

...

Keyword(s):

Interstellar Medium ◽

Spatial Scales ◽

Dense Gas ◽

Gas Stripping ◽

Ionized Gas ◽

Massive Galaxies ◽

Star Forming ◽

Diffuse Ionized Gas ◽

The Difference ◽

And Control

Abstract Diffuse ionized gas (DIG) is an important component of the interstellar medium that can provide insights into the different physical processes affecting the gas in galaxies. We utilize optical IFU observations of 71 gas-stripped and control galaxies from the Gas Stripping Phenomena in galaxies (GASP) survey, to analyze the gas properties of dense ionized gas and DIG, such as metallicity, ionization parameter log(q), and the difference between the measured log[O i]/Hα and the value predicted by star-forming models given the measured log[Oiii]/Hβ (Δ log[O i]/Hα). We compare these properties at different spatial scales, among galaxies at different gas-stripping stages, and between disks and tails of the stripped galaxies. The metallicity is similar between the dense gas and DIG at a given galactocentric radius. The log(q) is lower for DIG compared to dense gas. The median values of log(q) correlate best with stellar mass and the most massive galaxies show an increase in log(q) toward their galactic centers. The DIG clearly shows higher Δ log[O i]/Hα values compared to the dense gas, with much of the spaxels having LIER/LINER-like emission. The DIG regions in the tails of highly stripped galaxies show the highest Δ log[O i]/Hα, exhibit high values of log(q), and extend to large projected distances from star-forming areas (up to 10 kpc). We conclude that the DIG in the tails is at least partly ionized by a process other than star formation, probably by mixing, shocks, and accretion of inter-cluster and interstellar medium gas.

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Morphometry as a probe of the evolution of jellyfish galaxies: evidence of broadening in the surface brightness profiles of ram-pressure stripping candidates in the multicluster system A901/A902

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3226 ◽

2020 ◽

Vol 500 (1) ◽

pp. 40-53

Author(s):

Fernanda Roman-Oliveira ◽

Ana L Chies-Santos ◽

Fabricio Ferrari ◽

Geferson Lucatelli ◽

Bruno Rodríguez Del Pino

Keyword(s):

Star Formation ◽

Surface Brightness ◽

Quantitative Measurement ◽

Star Formation Rate ◽

Hubble Space Telescope ◽

Formation Rate ◽

Structural Evolution ◽

Star Forming ◽

Irregular Structures ◽

Ram Pressure

ABSTRACT We explore the morphometric properties of a group of 73 ram-pressure stripping candidates in the A901/A902 multicluster system, at z∼ 0.165, to characterize the morphologies and structural evolution of jellyfish galaxies. By employing a quantitative measurement of morphometric indicators with the algorithm morfometryka on Hubble Space Telescope (F606W) images of the galaxies, we present a novel morphology-based method for determining trail vectors. We study the surface brightness profiles and curvature of the candidates and compare the results obtained with two analysis packages, morfometryka and iraf/ellipse on retrieving information of the irregular structures present in the galaxies. Our morphometric analysis shows that the ram-pressure stripping candidates have peculiar concave regions in their surface brightness profiles. Therefore, these profiles are less concentrated (lower Sérsic indices) than other star-forming galaxies that do not show morphological features of ram-pressure stripping. In combination with morphometric trail vectors, this feature could both help identify galaxies undergoing ram-pressure stripping and reveal spatial variations in the star formation rate.

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The prospects for observing [O iii] 52 micron emission from galaxies during the Epoch of Reionization

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab925 ◽

2021 ◽

Vol 504 (1) ◽

pp. 723-730

Author(s):

Shengqi Yang ◽

Adam Lidz ◽

Gergö Popping

Keyword(s):

Fine Structure ◽

Interstellar Medium ◽

Emission Line ◽

Parameter Space ◽

Gas Density ◽

Star Forming ◽

Upper Limits ◽

Redshift Galaxies

ABSTRACT The [O iii] 88 $\mu$m fine-structure emission line has been detected into the Epoch of Reionization (EoR) from star-forming galaxies at redshifts 6 < z ≲ 9 with ALMA. These measurements provide valuable information regarding the properties of the interstellar medium (ISM) in the highest redshift galaxies discovered thus far. The [O iii] 88 $\mu$m line observations leave, however, a degeneracy between the gas density and metallicity in these systems. Here, we quantify the prospects for breaking this degeneracy using future ALMA observations of the [O iii] 52 $\mu$m line. Among the current set of 10 [O iii] 88 $\mu$m emitters at 6 < z ≲ 9, we forecast 52 $\mu$m detections (at 6σ) in SXDF-NB1006-2, B14-6566, J0217-0208, and J1211-0118 within on-source observing times of 2–10 h, provided their gas densities are larger than about nH ≳ 102–103 cm−3. Other targets generally require much longer integration times for a 6σ detection. Either successful detections of the 52 $\mu$m line or reliable upper limits will lead to significantly tighter constraints on ISM parameters. The forecasted improvements are as large as ∼3 dex in gas density and ∼1 dex in metallicity for some regions of parameter space. We suggest SXDF-NB1006-2 as a promising first target for 52 $\mu$m line measurements. We discuss how such measurements will help in understanding the mass–metallicity relationship during the EoR.

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The effect of photoionizing feedback on the shaping of hierarchically-forming stellar clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2921 ◽

2020 ◽

Vol 499 (1) ◽

pp. 668-680

Author(s):

Alejandro González-Samaniego ◽

Enrique Vazquez-Semadeni

Keyword(s):

Star Formation ◽

Early Stage ◽

Stellar Clusters ◽

Low Mass Stars ◽

Transfer Scheme ◽

Star Forming ◽

Secondary Star ◽

Low Mass ◽

Hydrodynamical Simulations ◽

Formation Efficiency

ABSTRACT We use two hydrodynamical simulations (with and without photoionizing feedback) of the self-consistent evolution of molecular clouds (MCs) undergoing global hierarchical collapse (GHC), to study the effect of the feedback on the structural and kinematic properties of the gas and the stellar clusters formed in the clouds. During this early stage, the evolution of the two simulations is very similar (implying that the feedback from low-mass stars does not affect the cloud-scale evolution significantly) and the star-forming region accretes faster than it can convert gas into stars, causing the instantaneous measured star formation efficiency (SFE) to remain low even in the absence of significant feedback. Afterwards, the ionizing feedback first destroys the filamentary supply to star-forming hubs and ultimately removes the gas from it, thus first reducing the star formation (SF) and finally halting it. The ionizing feedback also affects the initial kinematics and spatial distribution of the forming stars because the gas being dispersed continues to form stars, which inherit its motion. In the non-feedback simulation, the groups remain highly compact and do not mix, while in the run with feedback, the gas dispersal causes each group to expand, and the cluster expansion thus consists of the combined expansion of the groups. Most secondary star-forming sites around the main hub are also present in the non-feedback run, implying a primordial rather than triggered nature. We do find one example of a peripheral star-forming site that appears only in the feedback run, thus having a triggered origin. However, this appears to be the exception rather than the rule, although this may be an artefact of our simplified radiative transfer scheme.

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GASP – XX. From the loose spatially resolved to the tight global SFR–mass relation in local spiral galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1829 ◽

2019 ◽

Vol 488 (2) ◽

pp. 1597-1617 ◽

Cited By ~ 10

Author(s):

Benedetta Vulcani ◽

Bianca M Poggianti ◽

Alessia Moretti ◽

Andrea Franchetto ◽

Marco Gullieuszik ◽

...

Keyword(s):

Formation Rate ◽

Mass Relation ◽

Gas Stripping ◽

Massive Galaxies ◽

Star Forming ◽

Spatially Resolved ◽

The Galaxy ◽

Primary Driver ◽

Integral Field Spectrograph ◽

And Shifts

ABSTRACT Exploiting the sample of 30 local star-forming, undisturbed late-type galaxies in different environments drawn from the GAs Stripping Phenomena in galaxies with MUSE (GASP), we investigate the spatially resolved star formation rate–mass ($\rm \Sigma _{SFR}$–$\rm \Sigma _\ast$) relation. Our analysis includes also the galaxy outskirts (up to >4 effective radii, re), a regime poorly explored by other Integral Field Spectrograph surveys. Our observational strategy allows us to detect H α out to more than 2.7re for 75 per cent of the sample. Considering all galaxies together, the correlation between the $\rm \Sigma _{SFR}$ and $\rm \Sigma _\ast$ is quite broad, with a scatter of 0.3 dex. It gets steeper and shifts to higher $\rm \Sigma _\ast$ values when external spaxels are excluded and moving from less to more massive galaxies. The broadness of the overall relation suggests galaxy-by-galaxy variations. Indeed, each object is characterized by a distinct $\rm \Sigma _{SFR}$ –$\rm \Sigma _\ast$ relation and in some cases the correlation is very loose. The scatter of the relation mainly arises from the existence of bright off-centre star-forming knots whose $\rm \Sigma _{SFR}$–$\rm \Sigma _\ast$ relation is systematically broader than that of the diffuse component. The $\rm \Sigma _{SFR}$–$\rm \Sigma _{tot \, gas}$ (total gas surface density) relation is as broad as the $\rm \Sigma _{SFR}$–$\rm \Sigma _\ast$ relation, indicating that the surface gas density is not a primary driver of the relation. Even though a large galaxy-by-galaxy variation exists, mean $\rm \Sigma _{SFR}$ and $\rm \Sigma _\ast$ values vary of at most 0.7 dex across galaxies. We investigate the relationship between the local and global SFR–M* relation, finding that the latter is driven by the existence of the size–mass relation.

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The Violent Interstellar Medium of Nearby Dwarf Galaxies

Publications of the Astronomical Society of Australia ◽

10.1071/as99106 ◽

1999 ◽

Vol 16 (1) ◽

pp. 106-112 ◽

Cited By ~ 9

Author(s):

Fabian Walter

Keyword(s):

Interstellar Medium ◽

Gamma Ray ◽

Dwarf Galaxies ◽

Young Star ◽

Stellar Winds ◽

Star Forming ◽

Star Forming Regions ◽

Supernova Explosions ◽

High Velocity Clouds ◽

Ob Associations

AbstractHigh resolution HI observations of nearby dwarf galaxies (most of which are situated in the M81 group at a distance of about 3·2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M31 and M33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's gravitational potential. The origin of these features is still a matter of debate. In general, young star forming regions (OB-associations) are held responsible for their formation. This picture, however, is not without its critics and other mechanisms such as the infall of high velocity clouds, turbulent motions or even gamma ray bursters have been recently proposed. Here I will present one example of a supergiant shell in IC 2574 which corroborates the picture that OB associations are indeed creating these structures. This particular supergiant shell is currently the most promising case to study the effects of the combined effects of stellar winds and supernova explosions which shape the neutral interstellar medium of (dwarf) galaxies.

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Properties of the circumgalactic medium in simulations compared to observations

Astronomy and Astrophysics ◽

10.1051/0004-6361/201628886 ◽

2018 ◽

Vol 609 ◽

pp. A66 ◽

Cited By ~ 3

Author(s):

R. E. G. Machado ◽

P. B. Tissera ◽

G. B. Lima Neto ◽

L. Sodré

Keyword(s):

Gas Phase ◽

Chemical Elements ◽

Star Forming ◽

Physical Conditions ◽

Cosmological Context ◽

Circumgalactic Medium ◽

Hydrodynamical Simulations ◽

Stellar Masses ◽

Lower Limits ◽

Supernova Feedback

Context. Galaxies are surrounded by extended gaseous halos that store significant fractions of chemical elements. These are syntethized by the stellar populations and later ejected into the circumgalactic medium (CGM) by different mechanism, of which supernova feedback is considered one of the most relevant. Aims. We aim to explore the properties of this metal reservoir surrounding star-forming galaxies in a cosmological context aiming to investigate the chemical loop between galaxies and their CGM, and the ability of the subgrid models to reproduce observational results. Methods. Using cosmological hydrodynamical simulations, we have analysed the gas-phase chemical contents of galaxies with stellar masses in the range 109−1011 M⊙. We estimated the fractions of metals stored in the different CGM phases, and the predicted O vi and Si iii column densities within the virial radius. Results. We find roughly 107 M⊙ of oxygen in the CGM of simulated galaxies having M⋆ ~ 1010 M⊙, in fair agreement with the lower limits imposed by observations. The Moxy is found to correlate with M⋆, at odds with current observational trends but in agreement with other numerical results. The estimated profiles of O vi column density reveal a substantial shortage of that ion, whereas Si iii, which probes the cool phase, is overpredicted. Nevertheless, the radial dependences of both ions follow the respective observed profiles. The analysis of the relative contributions of both ions from the hot, warm and cool phases suggests that the warm gas (105 K < T < 106 K) should be more abundant in order to bridge the mismatch with the observations, or alternatively, that more metals should be stored in this gas-phase. These discrepancies provide important information to improve the subgrid physics models. Our findings show clearly the importance of tracking more than one chemical element and the difficulty of simultaneously satisfying the observables that trace the circumgalactic gas at different physical conditions. Additionally, we find that the X-ray coronae around the simulated galaxies have luminosities and temperatures in decent agreement with the available observational estimates.

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Observations of [OI]63 μm line emission in main-sequence galaxies at z ∼ 1.5

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2884 ◽

2020 ◽

Vol 499 (2) ◽

pp. 1788-1794

Author(s):

J Wagg ◽

M Aravena ◽

D Brisbin ◽

I Valtchanov ◽

C Carilli ◽

...

Keyword(s):

Field Strength ◽

Interstellar Medium ◽

Radiation Field ◽

Uv Radiation ◽

Main Sequence ◽

Line Emission ◽

The Other ◽

Low Density ◽

Star Forming ◽

Neutral Gas

ABSTRACT We present Herschel–PACS spectroscopy of four main-sequence star-forming galaxies at z ∼ 1.5. We detect [OI]63 μm line emission in BzK-21000 at z = 1.5213, and measure a line luminosity, $L_{\rm [O\, {\small I}]63\, \mu m} = (3.9\pm 0.7)\times 10^9$ L⊙. Our PDR modelling of the interstellar medium in BzK-21000 suggests a UV radiation field strength, G ∼ 320G0, and gas density, n ∼ 1800 cm−3, consistent with previous LVG modelling of the molecular CO line excitation. The other three targets in our sample are individually undetected in these data, and we perform a spectral stacking analysis which yields a detection of their average emission and an [O i]63 μm line luminosity, $L_{\rm [O\, {\small I}]63\, \mu m} = (1.1\pm 0.2)\times 10^9$ L⊙. We find that the implied luminosity ratio, $L_{\rm [O\, {\small I}]63\, \mu m}/L_{\rm IR}$, of the undetected BzK-selected star-forming galaxies broadly agrees with that of low-redshift star-forming galaxies, while BzK-21000 has a similar ratio to that of a dusty star-forming galaxy at z ∼ 6. The high [O i]63 μm line luminosities observed in BzK-21000 and the z ∼ 1−3 dusty and sub-mm luminous star-forming galaxies may be associated with extended reservoirs of low density, cool neutral gas.

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