English
Related papers

Related papers: [CII] observations of H$_2$ molecular layers in tr…

200 papers

We report the results of a rocket-borne observation of [C II] 158\micron line and far-infrared continuum emission at 152.5\micron toward the high latitude molecular clouds in Ursa Major. We also present the results of a follow-up…

We report a new search for 12CO(1-0) emission in high-velocity clouds (HVCs) performed with the IRAM 30 m telescope. This search was motivated by the recent detection of cold dust emission in the HVCs of Complex C. Despite a spatial…

Astrophysics · Physics 2009-11-13 M. Dessauges-Zavadsky , F. Combes , D. Pfenniger

Our understanding of how molecular clouds form in the interstellar medium (ISM) would be greatly helped if we had a reliable observational tracer of the gas flows responsible for forming the clouds. Fine structure emission from singly…

Astrophysics of Galaxies · Physics 2019-05-14 Paul C. Clark , Simon C. O. Glover , Sarah E. Ragan , Ana Duarte-Cabral

We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…

We examine the triggering process of molecular cloud formation around diffuse HII regions. We calculate the time evolution of the shell as well as of the HII region in a two-phase neutral medium, solving the UV and FUV radiative transfer,…

Astrophysics · Physics 2011-02-11 Takashi Hosokawa , Shu-ichiro Inutsuka

We present a pilot survey of 21 lines of sight towards UCHII regions in the H2CO 1-1 (6cm) and 2-2 (2cm) transitions, using the H2CO centimeter lines as a molecular gas densitometer. Using Arecibo and Green Bank beam-matched observations,…

Astrophysics of Galaxies · Physics 2011-07-27 Adam Ginsburg , Jeremy Darling , Cara Battersby , Ben Zeiger , John Bally

We present new observations of [CII] fine structure line emission from an isolated molecular cloud using the upGREAT instrument onboard SOFIA. These data are analyzed together with archival CO=1-0 and HI 21 cm emission spectra to…

Astrophysics of Galaxies · Physics 2022-12-21 Mark Heyer , Paul F. Goldsmith , Robert Simon , Rebeca Aladro , Oliver Ricken

We present the first 7.5'x11.5' velocity-resolved map of the [CII]158um line toward the Orion molecular cloud-1 (OMC-1) taken with the Herschel/HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved…

We aim to explore the capabilities of dust emission and rays for probing the properties of the interstellar medium in the nearby anti-centre region, using gamma-ray observations with the Fermi Large Area Telescope (LAT), and the thermal…

High Energy Astrophysical Phenomena · Physics 2017-05-10 Q. Remy , I. A. Grenier , D. J. Marshall , J. M. Casandjian

We use UV measurements of interstellar CO towards nearby stars to calculate the density in the diffuse molecular clouds containing the molecules responsible for the observed absorption. Chemical models and recent calculations of the…

Astrophysics of Galaxies · Physics 2015-06-16 Paul F. Goldsmith

We report on a study of the high-mass star formation in the the HII region W28A2 by investigating the molecular clouds extended over ~5-10 pc from the exciting stars using the 12CO and 13CO (J=1-0) and 12CO (J=2-1) data taken by the NANTEN2…

The process of atomic-to-molecular (HI-to-H$_2$) gas conversion is fundamental for molecular-cloud formation and star formation. 21 cm observations of the star-forming region W43 revealed extremely high HI column densities, of 120-180…

Astrophysics of Galaxies · Physics 2017-02-01 Shmuel Bialy , Simon Bihr , Henrik Beuther , Thomas Henning , Amiel Sternberg

We aim to understand the contribution of the ionized, atomic and molecular phases of the ISM to the [CII] emission from clouds near the dynamical center and the BCLMP302 HII region in the north of the nearby galaxy M33 at a spatial…

Studying the atomic-to-molecular transition is essential for understanding the evolution of interstellar medium. The linear edge of Taurus molecular cloud, clearly identified in the $^{13}$CO(1-0) intensity map, serves as an ideal site for…

Astrophysics of Galaxies · Physics 2025-04-03 Ningyu Tang , Feihang Miao , Gan Luo , Di Li , Junzhi Wang , Fujun Du , Donghong Wu , Shu Liu

We investigate the chemical evolution of a forming molecular cloud behind an interstellar shock wave. We conduct three-dimensional magnetohydrodynamics simulations of the converging flow of atomic gas, including a simple chemical network…

Astrophysics of Galaxies · Physics 2026-01-08 Yuto Komichi , Yuri Aikawa , Kazunari Iwasaki , Kenji Furuya

We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical…

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

We present search results of 22 high latitude (b > 25 deg.) sightlines for OH 18-cm emission using the 305-m radio telescope at the Arecibo Observatory. These sightlines appear in neutral hydrogen emission at intermediate velocities (V_lsr…

Astrophysics of Galaxies · Physics 2023-05-10 Allison Smith , D. Anish Roshi

We have used archival far-ultraviolet spectra from observations made by HST/STIS and FUSE to determine the column densities and rotational excitation temperatures for CO and H2, respectively, along the lines of sight to 23 Galactic O and B…

Astrophysics · Physics 2009-01-19 Eric B. Burgh , Kevin France , Stephan R. McCandliss

We describe a moderate-resolution FUSE survey of H2 along 70 sight lines to the Small and Large Magellanic Clouds, using hot stars as background sources. FUSE spectra of 67% of observed Magellanic Cloud sources (52% of LMC and 92% of SMC)…