I(CO)/N(H2) conversions and molecular gas abundances in spiral and irregular galaxies

Maloney, Philip R.; Black, J. H.

doi:10.1086/166011

Cited by 323 publications

(331 citation statements)

References 0 publications

Supporting

Mentioning

313

Contrasting

Order By: Relevance

“…Towards the outer molecular lobes with higher H 2 densities and lower kinetic temperatures, the conversion factor rises. This is in agreement with simple theoretical arguments that suggest that the conver- for virialized clouds (Maloney & Black 1988). The variation of X CO with T −1 kin n(H 2 ) 1/2 is shown in Fig.…”

Section: Conversion From I(co) To N (H 2 ) and Total Masssupporting

confidence: 89%

The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

Weiß

Neininger

Hüttemeister

et al. 2001

The Evolution of Galaxies

View full text Add to dashboard Cite

Abstract. We present the results of a high angular resolution, multi-transition analysis of the molecular gas in M 82. The analysis is based on the two lowest transitions of 12 CO and the ground transition of the rare isotopes 13 CO and C 18 O measured with the PdBI, the BIMA array and the IRAM 30m telescope. In order to address the question of how the intrinsic molecular cloud properties are influenced by massive star formation we have carried out radiative transfer calculations based on the observed CO line ratios. The calculations suggest that the kinetic temperature of the molecular gas is high in regions with strong star formation and drops towards the outer molecular lobes with less ongoing star formation. The location of the highest kinetic temperature is coincident with that of the mid infrared (MIR) peaks which trace emission from hot dust. The hot gas is associated with low H 2 densities while the cold gas in the outer molecular lobes has high H 2 densities. We find that CO intensities do not trace H 2 column densities well. Most of the molecular gas is distributed in a double-lobed distribution which surrounds the starburst. A detailed analysis of the conversion factor from CO intensity to H 2 column density shows that X CO depends on the excitation conditions. We find X CO ∼ T −1 kin n(H 2 ) 1/2 , as expected for virialized clouds.

show abstract

Section: Conversion From I(co) To N (H 2 ) and Total Masssupporting

confidence: 89%

The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

Weiß

Neininger

Hüttemeister

et al. 2001

The Evolution of Galaxies

View full text Add to dashboard Cite

show abstract

“…Given that the global physical properties of molecular clouds within the Milky Way occupy a relatively limited range (i.e. gas temperatures, GMC velocity dispersion and cloud surface density), this result is not terribly surprising (Maloney & Black, 1988;McKee & Ostriker, 2007;Feldmann et al, 2012a;Shetty et al, 2011b;Narayanan & Hopkins, 2013). Observations have noted two major points of departure from this relative constancy in the X-factor observed in the Local Group.…”

Section: Deriving H 2 Gas Masses From High-redshift Galaxiesmentioning

confidence: 97%

Dusty star-forming galaxies at high redshift

2014

View full text Add to dashboard Cite

Far-infrared and submillimeter wavelength surveys have now established the important role of dusty, star-forming galaxies (DSFGs) in the assembly of stellar mass and the evolution of massive galaxies in the Universe. The brightest of these galaxies have infrared luminosities in excess of 10 13 L with implied star-formation rates of thousands of solar masses per year. They represent the most intense starbursts in the Universe, yet many are completely optically obscured. Their easy detection at submm wavelengths is due to dust heated by ultraviolet radiation of newly forming stars. When summed up, all of the dusty, star-forming galaxies in the Universe produce an infrared radiation field that has an equal energy density as the direct starlight emission from all galaxies visible at ultraviolet and optical wavelengths. The bulk of this infrared extragalactic background light emanates from galaxies as diverse as gas-rich disks to mergers of intense starbursting galaxies. Major advances in far-infrared instrumentation in recent years, both spacebased and ground-based, has led to the detection of nearly a million DSFGs, yet our understanding of the underlying astrophysics that govern the start and end of the dusty starburst phase is still in nascent stage. This review is aimed at summarizing the current status of DSFG studies, focusing especially on the detailed characterization of the bestunderstood subset (submillimeter galaxies, who were summarized in the last review of this field over a decade ago, Blain et al. 2002), but also the selection and characterization of more recently discovered DSFG populations. We review DSFG population statistics, their physical properties including dust, gas and stellar contents, their environments, and current theoretical models related to the formation and evolution of these galaxies.

show abstract

“…Low metallicity has been invoked to explain these sources (e.g. Maloney & Black 1988;Stacey et al 1991a;Madden et al 1997). Considering this effect is beyond the scope of this paper.…”

Section: Different [Cii] and Co Excitation Temperaturesmentioning

confidence: 99%

The nature of the [C ii] emission in dusty star-forming galaxies from the SPT survey

Gullberg

Breuck

Vieira

et al. 2015

Monthly Notices of the Royal Astronomical Society

147

223

View full text Add to dashboard Cite

We present [CII] observations of 20 strongly lensed dusty star forming galaxies at 2.1 < z < 5.7 using APEX and Herschel. The sources were selected on their 1.4 mm flux (S 1.4 mm > 20 mJy) from the South Pole Telescope survey, with far-infrared (FIR) luminosities determined from extensive photometric data. The [CII] line is robustly detected in 17 sources, all but one being spectrally resolved. Eleven out of 20 sources observed in [CII] also have low-J CO detections from ATCA. A comparison with midand high-J CO lines from ALMA reveals consistent [CII] and CO velocity profiles, suggesting that there is little differential lensing between these species. The [CII], low-J CO and FIR data allow us to constrain the properties of the interstellar medium. We find [CII] to CO(1-0) luminosity ratios in the SPT sample of 5200 ± 1800, with significantly less scatter than in other samples. This line ratio can be best described by a medium of [CII] and CO emitting gas with a higher [CII] than CO excitation temperature, high CO optical depth τ CO (1-0) 1, and low to moderate [CII] optical depth τ [CII] 1. The geometric structure of photodissociation regions allows for such conditions.

show abstract

I(CO)/N(H2) conversions and molecular gas abundances in spiral and irregular galaxies

Cited by 323 publications

References 0 publications

The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

The Effect of Violent Star Formation on the State of the Molecular Gas in M 82

Dusty star-forming galaxies at high redshift

The nature of the [C ii] emission in dusty star-forming galaxies from the SPT survey

Contact Info

Product

Resources

About