scholarly journals Analysis of the Interstellar Medium Properties of the Herschel Reference Survey Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 284-284
Author(s):  
Laure Ciesla ◽  
Keyword(s):  
Interstellar Medium ◽  
Physical Properties ◽  
Radiation Field ◽  
Statistical Study ◽  
Dust Mass ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Photodissociation Regions ◽  
K Band

AbstractThe Herschel Reference Survey is a guaranteed time key project aimed at studying the physical properties of the interstellar medium (ISM) of 323 nearby galaxies, covered by multi-wavelength data. This volume limited, K-band selected sample is composed of galaxies spanning the whole range of morphological types and environments. We conduct a statistical study on the ISM properties of nearby galaxies based on the analysis of their SED. To achieve this goal, we fit the data with the models of Draine & Li (2007) to obtain the intensity of interstellar radiation field, the PAH abundance, the contribution of photodissociation regions, and the dust mass.

scholarly journals The Interstellar Medium in Nearby Galaxies

1992 ◽  
Vol 9 ◽  
pp. 101-107
Author(s):  
J. M. Van Der Hulst
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Physical Properties ◽  
Close Interaction ◽  
Wide Range ◽  
Nearby Galaxies

AbstractRecent observations of the several phases of the interstellar medium in galaxies reveal a wide range of structures and physical properties. The HI structure in nearby galaxies is very filamentary with a large number of shells and filaments suggestive of a close interaction between the star formation in the disk and the surrounding interstellar medium.

scholarly journals Spatially resolving the dust properties and submillimetre excess in M 33

2018 ◽  
Vol 613 ◽  
pp. A43 ◽  
Author(s):  
M. Relaño ◽  
I. De Looze ◽  
R. C. Kennicutt ◽  
U. Lisenfeld ◽  
A. Dariush ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Physical Properties ◽  
Relative Abundance ◽  
Radial Dependence ◽  
Dust Grains ◽  
Star Forming ◽  
Star Forming Regions ◽  
Dust Mass ◽  
The Galaxy ◽  
Dust Grain

Context. The relative abundance of the dust grain types in the interstellar medium is directly linked to physical quantities that trace the evolution of galaxies. Because of the poor spatial resolution of the infrared and submillimetre data, we are able to study the dependence of the resolved infrared spectral energy distribution (SED) across regions of the interstellar medium (ISM) with different physical properties in just a few objects. Aims. We aim to study the dust properties of the whole disc of M 33 at spatial scales of ~170 pc. This analysis allows us to infer how the relative dust grain abundance changes with the conditions of the ISM, study the existence of a submillimetre excess and look for trends of the gas-to-dust mass ratio (GDR) with other physical properties of the galaxy. Methods. For each pixel in the disc of M 33 we have fitted the infrared SED using a physically motivated dust model that assumes an emissivity index β close to two. We applied a Bayesian statistical method to fit the individual SEDs and derived the best output values from the study of the probability density function of each parameter. We derived the relative amount of the different dust grains in the model, the total dust mass, and the strength of the interstellar radiation field (ISRF) heating the dust at each spatial location. Results. The relative abundance of very small grains tends to increase, and for big grains to decrease, at high values of Hα luminosity. This shows that the dust grains are modified inside the star-forming regions, in agreement with a theoretical framework of dust evolution under different physical conditions. The radial dependence of the GDR is consistent with the shallow metallicity gradient observed in this galaxy. The strength of the ISRF derived in our model correlates with the star formation rate in the galaxy in a pixel by pixel basis. Although this is expected, it is the first time that a correlation between the two quantities has been reported. We have produced a map of submillimetre excess in the 500 μm SPIRE band for the disc of M 33. The excess can be as high as 50% and increases at large galactocentric distances. We further studied the relation of the excess with other physical properties of the galaxy and find that the excess is prominent in zones of diffuse ISM outside the main star-forming regions, where the molecular gas and dust surface density are low.

scholarly journals Massive stars shaping the ISM: H I holes and shells in nearby galaxies

1999 ◽  
Vol 193 ◽  
pp. 636-644
Author(s):  
Elias Brinks ◽  
Fabian Walter
Keyword(s):  
Interstellar Medium ◽  
Dwarf Galaxy ◽  
Massive Stars ◽  
Neutral Hydrogen ◽  
Neutral Medium ◽  
Stellar Winds ◽  
X Ray ◽  
Left Behind ◽  
Neutral Gas ◽  
Nearby Galaxies

Neutral hydrogen (H I) is a magnificent tool when studying the structure of the interstellar medium (ISM) as it is relatively easily observable and can be mapped at good spatial and velocity resolution with modern instruments. Moreover, it traces the cool (∼ 100 K) and warm (∼ 5000 K) neutral gas which together make up about 60%, or the bulk, of the ISM. The currently accepted picture is that stellar winds and subsequent supernovae are the origin for the clearly defined holes or bubbles within the more or less smooth neutral medium. The H I can therefore serve indirectly as a tracer of the hot interstellar medium (HIM) left behind after the most massive stars within an OB association have gone off as supernovae. A splendid example is the dwarf galaxy IC 2574 for which we discuss H I, optical and X-ray observations.

scholarly journals Enrichment by Wolf-Rayet Stars and Other Massive Stars in Gas, Dust and Energy

1991 ◽  
Vol 143 ◽  
pp. 323-334
Author(s):  
Martin Cohen
Keyword(s):  
Interstellar Medium ◽  
Infrared Spectra ◽  
Stellar Wind ◽  
Massive Stars ◽  
Observational Evidence ◽  
Radiative Energy ◽  
New Members ◽  
Hot Gas ◽  
Sn 1987A ◽  
Dust Mass

I update previous estimates of the separate contributions for radiative energy, integrated total stellar wind mass and dust mass from Wolf-Rayet stars and other massive (OBA) stars. In the context of the intriguing dusty WC9 stars, I: (1) discuss the observability (or otherwise) between 0.4 and 23 μm of the condensation route from hot gas to carbon-rich grains; (2) urge caution in the use of 10 μm infrared spectra of these luminous stars to deduce the importance of silicates as a component of the interstellar medium, and (3) speculate on a possible new method for discovering new members of this relatively rare subtype based on IRAS Low Resolution Spectra. I review the observational evidence for dust condensation around SN 1987A.

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

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.

scholarly journals The UM/CTIO Magellanic Cloud Emission-line Survey

1999 ◽  
Vol 190 ◽  
pp. 28-31 ◽  
Author(s):  
R. Chris Smith ◽  
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Supernova Remnants ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
H Ii Regions ◽  
Deep Imaging ◽  
Small Scales ◽  
Nearby Galaxies ◽  
Line Survey

The Magellanic Clouds are unique in providing sites to study the interstellar medium (ISM) and its components at all scales. To promote the pursuit of such studies, we have begun the Magellanic Cloud Emission-line Survey (MCELS), a deep imaging survey of both of these nearby galaxies in the emission of Hα, [S II], and [O III]. The emission-line images will be used in detailed optical and multiwavelength studies of H II regions, supernova remnants, planetary nebulae, superbubbles, and supergiant shells. Together with parallel surveys at other wavelengths, this survey will provide the foundation upon which to build a deeper understanding of the ISM in the Clouds and other galaxies, from small scales (~1 pc) all the way up to global scales. We present a sample of recent and current work using the MCELS dataset.

scholarly journals Supershells

1988 ◽  
Vol 101 ◽  
pp. 447-459
Author(s):  
Richard McCray
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Interstellar Medium ◽  
Milky Way ◽  
Disk Galaxy ◽  
Interstellar Gas ◽  
Irregular Galaxies ◽  
Nearby Galaxies ◽  
Gas Layer

AbstractRepeated supernovae from an OB association will, in a few ×107 yr, create a cavity of coronal gas in the interstellar medium, with radius > 100 pc, surrounded by a dense expanding shell of cool interstellar gas. Such a cavity will likely burst through the gas layer of a disk galaxy. Such holes and “supershells” have been observed in optical and H I radio emission maps of the Milky Way and other nearby galaxies. The gas swept up in the supershell is likely to become gravitationally unstable, providing a mechanism for propagating star formation that may be particularly effective in irregular galaxies.

scholarly journals Discovery of Carbon Radio Recombination Lines in M82

2014 ◽  
Vol 10 (S309) ◽  
pp. 141-144
Author(s):  
Leah K. Morabito ◽  
J. B. R. Oonk ◽  
Francisco Salgado ◽  
M. Carmen Toribio ◽  
Xander Tielens ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Physical Properties ◽  
Neutral Medium ◽  
Radio Recombination Lines ◽  
Evolution Of Galaxies

AbstractCold, diffuse HI clouds are a key component of the interstellar medium (ISM), and play an important role in the evolution of galaxies. Carbon radio recombination lines (CRRLs) trace this ISM stage, and with the enormous sensitivity of LOFAR we have already begun to map and constrain the physical properties of this gas in our own Galaxy. Using LOFAR's low band antenna, we have observed M 82 and present the first ever extragalactic detection of CRRLs. We stack 22 lines to find a 8.5-sigma detection. The line peak to continuum ratio is ∼0.003, with a FWHM of 31 km s−1. The CRRL feature is consistent with an origin in the cold, neutral medium in the direction of the nucleus of M 82.

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