Morphology of the interstellar cooling lines detected by COBE

Bennett, C. L.; Fixsen, D. J.; Hinshaw, G.; Mather, John C.; Moseley, S. H.; Wright, E. L.; Eplee, Robert E.; Gales, Joel; Hewagama, T.; Isaacman, R.; Shafer, R. A.; Turpie, K.

doi:10.1086/174761

Cited by 212 publications

(242 citation statements)

References 43 publications

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“…The large-scale structure of this map is similar to the map of C + /N H  , obtained from lower-resolution data by Bennett et al (1994), that also traces U.…”

Section: The Strength Of the Isrfsupporting

confidence: 76%

Planck2013 results. XI. All-sky model of thermal dust emission

Abergel¹,

Ade²,

Aghanim³

et al. 2014

A&A

600

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This paper presents an all-sky model of dust emission from the Planck 353, 545, and 857 GHz, and IRAS 100 µm data. Using a modified blackbody fit to the data we present all-sky maps of the dust optical depth, temperature, and spectral index over the 353-3000 GHz range. This model is a good representation of the IRAS and Planck data at 5 between 353 and 3000 GHz (850 and 100 µm). It shows variations of the order of 30% compared with the widely-used model of Finkbeiner, Davis, and Schlegel. The Planck data allow us to estimate the dust temperature uniformly over the whole sky, down to an angular resolution of 5 , providing an improved estimate of the dust optical depth compared to previous all-sky dust model, especially in high-contrast molecular regions where the dust temperature varies strongly at small scales in response to dust evolution, extinction, and/or local production of heating photons. An increase of the dust opacity at 353 GHz, τ 353 /N H , from the diffuse to the denser interstellar medium (ISM) is reported. It is associated with a decrease in the observed dust temperature, T obs , that could be due at least in part to the increased dust opacity. We also report an excess of dust emission at H  column densities lower than 10 20 cm −2 that could be the signature of dust in the warm ionized medium. In the diffuse ISM at high Galactic latitude, we report an anticorrelation between τ 353 /N H and T obs while the dust specific luminosity, i.e., the total dust emission integrated over frequency (the radiance) per hydrogen atom, stays about constant, confirming one of the Planck Early Results obtained on selected fields. This effect is compatible with the view that, in the diffuse ISM, T obs responds to spatial variations of the dust opacity, due to variations of dust properties, in addition to (small) variations of the radiation field strength. The implication is that in the diffuse high-latitude ISM τ 353 is not as reliable a tracer of dust column density as we conclude it is in molecular clouds where the correlation of τ 353 with dust extinction estimated using colour excess measurements on stars is strong. To estimate Galactic E(B − V) in extragalactic fields at high latitude we develop a new method based on the thermal dust radiance, instead of the dust optical depth, calibrated to E(B− V) using reddening measurements of quasars deduced from Sloan Digital Sky Survey data.

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“…The large-scale structure of this map is similar to the map of C + /N H  , obtained from lower-resolution data by Bennett et al (1994), that also traces U.…”

Section: The Strength Of the Isrfsupporting

confidence: 76%

Planck2013 results. XI. All-sky model of thermal dust emission

Abergel¹,

Ade²,

Aghanim³

et al. 2014

A&A

600

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“…The [C ] 157 µm line has been studied in a variety of objects, such as Galactic PDRs (e.g., Bennett et al 1994;Pineda et al 2013), normal spiral galaxies (Stacey et al 1991;Malhotra et al 1997;Negishi et al 2001;Brauher et al 2008), lowmetallicity galaxies (Poglitsch et al 1995;Madden et al 1997;Hunter et al 2001;Israel & Maloney 2011;Cigan et al 2015), ultra-luminous IR galaxies (ULIRG, Luhman et al 1998;Farrah et al 2013), and high-redshift galaxies (Maiolino et al 2009;Stacey et al 2010;Hailey-Dunsheath et al 2010;Swinbank et al 2012;De Breuck et al 2014). From those studies (see Genzel & Cesarsky 2000, for a review), the [C ] line emerges as the brightest cooling line of the ISM in star-forming galaxies and as a good tracer of the star formation activity, accounting for ∼0.1-1% of the FIR luminosity (e.g., Stacey et al 2010;Pierini et al 2003;Boselli et al 2002;De Looze et al 2011, 2014aSargsyan et al 2014).…”

Section: Introductionmentioning

confidence: 99%

TheHerschelDwarf Galaxy Survey

Cormier

Madden

Lebouteiller

et al. 2015

A&A

238

399

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Context. The far-infrared (FIR) lines are important tracers of the cooling and physical conditions of the interstellar medium (ISM) and are rapidly becoming workhorse diagnostics for galaxies throughout the universe. There are clear indications of a different behavior of these lines at low metallicity that needs to be explored. Aims. Our goal is to explain the main differences and trends observed in the FIR line emission of dwarf galaxies compared to more metal-rich galaxies, and how this translates in ISM properties. ] 57 µm fine-structure cooling lines in a sample of 48 low-metallicity star-forming galaxies of the guaranteed time key program Dwarf Galaxy Survey. We correlate PACS line ratios and line-to-L TIR ratios with L TIR , L TIR /L B , metallicity, and FIR color, and interpret the observed trends in terms of ISM conditions and phase filling factors with Cloudy radiative transfer models. Results. We find that the FIR lines together account for up to 3 percent of L TIR and that star-forming regions dominate the overall emission in dwarf galaxies. Compared to metal-rich galaxies, the ratios of Harboring compact phases of a low filling factor and a large volume filling factor of diffuse gas, the ISM of low-metallicity dwarf galaxies has a more porous structure than that of metal-rich galaxies. Methods

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“…Wright et al 1991;Bennett et al 1994), with angular resolution of 7 • and velocity resolution ∼1000 km s −1 .…”

Section: Introductionmentioning

confidence: 99%

AHerschel[C ii] Galactic plane survey

Langer

Velusamy

Pineda

et al. 2014

A&A

153

184

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Context. H i and CO large scale surveys of the Milky Way trace the diffuse atomic clouds and the dense shielded regions of molecular hydrogen clouds, respectively. However, until recently, we have not had spectrally resolved C + surveys in sufficient lines of sight to characterize the ionized and photon dominated components of the interstellar medium, in particular, the H 2 gas without CO, referred to as CO-dark H 2 , in a large sample of interstellar clouds.Aims. We use a sparse Galactic plane survey of the 1.9 THz (158 μm) [C ii] spectral line from the Herschel open time key programme, Galactic Observations of Terahertz C+ (GOT C+), to characterize the H 2 gas without CO in a statistically significant sample of interstellar clouds.Methods. We identify individual clouds in the inner Galaxy by fitting the [C ii] and CO isotopologue spectra along each line of sight. We then combine these spectra with those of H i and use them along with excitation models and cloud models of C + to determine the column densities and fractional mass of CO-dark H 2 clouds.Results. We identify1804 narrow velocity [C ii] components corresponding to interstellar clouds in different categories and evolutionary states. About 840 are diffuse molecular clouds with no CO, ∼510 are transition clouds containing [C ii] and 12 CO, but no 13 CO, and the remainder are dense molecular clouds containing 13 CO emission. The CO-dark H 2 clouds are concentrated between Galactic radii of ∼3.5 to 7.5 kpc and the column density of the CO-dark H 2 layer varies significantly from cloud to cloud with a global average of 9 × 10 20 cm −2 . These clouds contain a significant fraction by mass of CO-dark H 2 , that varies from ∼75% for diffuse molecular clouds to ∼20% for dense molecular clouds.Conclusions. We find a significant fraction of the warm molecular ISM gas is invisible in H i and CO, but is detected in [C ii]. The fraction of CO-dark H 2 is greatest in the diffuse clouds and decreases with increasing total column density, and is lowest in the massive clouds. The column densities and mass fraction of CO-dark H 2 are less than predicted by models of diffuse molecular clouds using solar metallicity, which is not surprising as most of our detections are in Galactic regions where the metallicity is larger and shielding more effective. There is an overall trend towards a higher fraction of CO-dark H 2 in clouds with increasing Galactic radius, consistent with lower metallicity there.

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Morphology of the interstellar cooling lines detected by COBE

Cited by 212 publications

References 43 publications

Planck2013 results. XI. All-sky model of thermal dust emission

Planck2013 results. XI. All-sky model of thermal dust emission

TheHerschelDwarf Galaxy Survey

AHerschel[C ii] Galactic plane survey

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