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The CO-to-H$_2$ conversion factor ($\alpha_\rm{CO}$) is critical to studying molecular gas and star formation in galaxies. The value of $\alpha_\rm{CO}$ has been found to vary within and between galaxies, but the specific environmental…

FUSE and IUE observations of Sk -69 246, a WN 6 star to the north of 30 Dor, reveal the existence of LMC interstellar gas in at least 3 velocity components.In one of these components FUSE spectra show strong absorption by molecular hydrogen…

Astrophysics · Physics 2009-11-07 Hartmut Bluhm , Klaas S. de Boer

Formaldehyde (H$_2$CO) is an important precursor to organics like methanol (CH$_3$OH). It is important to understand the conditions that produce H$_2$CO and prebiotic molecules during star and planet formation. H$_2$CO possesses both…

We estimate the conversion factor relating CO emission to H2 mass, alpha_CO, in five Local Group galaxies that span approximately an order of magnitude in metallicity - M31, M 33, the Large Magellanic Cloud (LMC), NGC 6822, and the Small…

We investigate the temperature distribution of CO-dark molecular hydrogen (H2) in a series of disk galaxies simulated using the AREPO moving-mesh code. In conditions similar to those in the Milky Way, we find that H2 has a flat temperature…

Astrophysics of Galaxies · Physics 2016-08-31 Simon C. O. Glover , Rowan J. Smith

The importance of the physical environment in the evolution of newly formed low-mass stars remains an open question. In particular, radiation from nearby more massive stars may affect both the physical and chemical structure of these kinds…

Solar and Stellar Astrophysics · Physics 2012-09-25 J. E. Lindberg , J. K. Jørgensen

We present a new 12CO(J=1-0)-line survey of the Andromeda galaxy, M31, covering the bright disk with the highest resolution to date (85 pc along the major axis), observed On-the-Fly (in italics) with the IRAM 30-m telescope. We discuss the…

We report the first detection of gas-phase CO2 emission in the star-forming region Cepheus A East, obtained by spectral line mapping of the v2 bending mode at 14.98 micron with the Infrared Spectrograph (IRS) instrument onboard the Spitzer…

New and archival interferometric 12CO(1->0) datasets from six nearby galaxies are combined with H_2 2.122um and H-alpha maps to explore in detail the interstellar medium in different star-forming galaxies. We investigate the relation…

We present 13CO(J=1-0) line emission observations with the Nobeyama 45-m telescope toward the giant HII region NGC 604 in the spiral galaxy M 33. We detected 13CO(J=1-0) line emission in 3 major giant molecular clouds (GMCs) labeled as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Kazuyuki Muraoka , Tomoka Tosaki , Rie Miura , Sachiko Onodera , Nario Kuno , Kouichiro Nakanishi , Hiroyuki Kaneko , Shinya Komugi

There is growing evidence that the properties of the molecular gas in the nuclei of starburst galaxies and in AGN may be very different from those seen in Galactic star forming regions and that a high kinetic temperature in the molecular…

Astrophysics of Galaxies · Physics 2009-04-14 S. Mühle , E. R. Seaquist , C. Henkel

The heart of the Large Magellanic Cloud, 30 Doradus, is a complex region with a clear core-halo structure. Feedback from the stellar cluster R$\,$136 has been shown to be the main source of energy creating multiple pc-scale expanding-shells…

We present APEX 218 GHz observations of molecular emission in a complete sample of embedded protostars in the Ophiuchus star-forming region. To study the physical properties of the cores, we calculate H$_2$CO and c-C$_3$H$_2$ rotational…

Solar and Stellar Astrophysics · Physics 2017-01-25 Johan E. Lindberg , Steven B. Charnley , Jes K. Jørgensen , Martin A. Cordiner , Per Bjerkeli

We derive distributions of dust temperature and dust opacity across M31 at 45" resolution using the Spitzer data. With the opacity map and a standard dust model we de-redden the Ha emission yielding the first de-reddened Ha map of M31. We…

Astrophysics of Galaxies · Physics 2015-05-18 F. S. Tabatabaei , E. M. Berkhuijsen

Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have…

We analyse the CO-dark molecular gas content of simulated molecular clouds from the SILCC-Zoom project. The simulations reach a resolution of 0.1 pc and include H$_2$ and CO formation, radiative stellar feedback and magnetic fields. CO-dark…

Astrophysics of Galaxies · Physics 2020-01-08 D. Seifried , S. Haid , S. Walch , E. M. A. Borchert , T. G. Bisbas

We present Green Bank Telescope (GBT) observations of the 3(12)-3(13) (29 GHz) and 4(13)-4(14) (48 GHz) transitions of the H2CO molecule toward a sample of 23 well-studied star-forming regions. Analysis of the relative intensities of these…

Astrophysics of Galaxies · Physics 2015-05-30 Patrick I. McCauley , Jeffrey G. Mangum , Alwyn Wootten

Within the key project "Herschel M33 extended survey" (HerM33es), we are studying the physical and chemical processes driving star formation and galactic evolution in the nearby galaxy M33, combining the study of local conditions affecting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 C. Kramer , M. Boquien , J. Braine , C. Buchbender , D. Calzetti , P. Gratier , B. Mookerjea , M. Relano , S. Verley

We report and analyse FIR observations of two Herbig Be stars, R Mon and PDS 27, obtained with Herschel's instruments PACS and SPIRE. We construct SEDs and derive the infrared excess. We extract line fluxes from the PACS and SPIRE spectra…

Solar and Stellar Astrophysics · Physics 2017-09-13 M. J. Jiménez-Donaire , G. Meeus , A. Karska , B. Montesinos , J. Bouwman , C. Eiroa , T. Henning

With a goal toward deriving the physical conditions in external galaxies, we present a survey of formaldehyde (H2CO) and ammonia (NH3) emission and absorption in a sample of starburst galaxies using the Green Bank Telescope. By extending…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jeffrey G. Mangum , Jeremy Darling , Karl M. Menten , Christian Henkel , Meredith MacGregor