English
Related papers

Related papers: Diffuse Molecular Cloud Densities from UV Measurem…

200 papers

Context. There are significant amounts of H2 in the Milky Way. Due to its symmetry H2 does not radiate at radio frequencies. CO is thought to be a tracer for H2, however CO is formed at significantly higher opacities than H2. Thus, toward…

Astrophysics of Galaxies · Physics 2020-07-08 P. M. W. Kalberla , J. Kerp , U. Haud

Far-infrared molecular emission is an important tool used to understand the excitation mechanisms of the gas in the inter-stellar medium of star-forming galaxies. In the present work, we model the emission from rotational transitions with…

Astrophysics of Galaxies · Physics 2016-11-23 M. V. Kazandjian , I. Pelupessy , R. Meijerink , F. P. Israel , C. M. Coppola , M. J. F. Rosenberg , M. Spaans

The cosmic-ray ionization rate (CRIR, $\zeta_2$) is one of the key parameters controlling the formation and destruction of various molecules in molecular clouds. However, the current most commonly used CRIR tracers, such as H$_3^+$, OH$^+$,…

Astrophysics of Galaxies · Physics 2023-04-07 Gan Luo , Zhiyu Zhang , Thomas G. Bisbas , Di Li , Ping Zhou , Ningyu Tang , Junzhi Wang , Pei Zuo , Nannan Yue

We present results of analysis of physical conditions (number density, intensity of UV field, kinetic temperature) in the cold H$_2$-bearing interstellar medium of local and high redshift galaxies. Our measurements based on the fit to the…

Astrophysics of Galaxies · Physics 2020-10-07 V. V. Klimenko , S. A. Balashev

We combine data from our recent FUSE survey of interstellar molecular hydrogen absorption toward 50 high-latitude AGN with COBE-corrected IRAS 100 micron emission maps to study the correlation of infrared cirrus with H2. A plot of the H2…

Astrophysics · Physics 2009-11-13 Kristen Gillmon , J. Michael Shull

Measuring the temperature and abundance patterns of clouds in the interstellar medium (ISM) provides an observational basis for models of the physical conditions within the clouds, which play an important role in studies of star and planet…

Astrophysics of Galaxies · Physics 2019-06-26 Nicholas Kruczek , Kevin France , Keri Hoadley , Brian Fleming , Nicholas Nell

Data from the Five College Radio Astronomy Observatory CO Mapping Survey of the Taurus molecular cloud are combined with extinction data for a sample of 292 background field stars to investigate the uptake of CO from the gas to icy grain…

Astrophysics of Galaxies · Physics 2010-07-20 D. C. B. Whittet , P. F. Goldsmith , J. L. Pineda

A reliable estimate of the molecular gas content in galaxies plays a crucial role in determining their dynamical and star-forming properties. However, H2, the dominant molecular species, is difficult to observe directly, particularly in the…

Astrophysics · Physics 2008-11-26 T. A. Bell , E. Roueff , S. Viti , D. A. Williams

We report results from our mini-survey for molecular hydrogen in eight high redshift damped Lyman-alpha (DLA) systems using the ESO Ultra-violet and Visible Spectrograph on the VLT. In addition, we investigate two systems using ESO public…

Astrophysics · Physics 2007-05-23 Patrick Petitjean , R. Srianand , Cédric Ledoux

We study the physical conditions in DLAs, using a sample of 33 systems toward 26 QSOs acquired for a recently completed survey of H_2 by Ledoux et al. (2003). We use the column densities of H_2 in different rotational levels, together with…

Astrophysics · Physics 2009-11-13 Raghunathan Srianand , Patrick Petitjean , Cedric Ledoux , Gary Ferland , Gargi Shaw

We study the relationship between molecular gas and dust in the California Molecular Cloud over an unprecedented dynamic range of cloud depth (Av = 3 - 60 magnitudes). We compare deep Herschel-based measurements of dust extinction with…

Astrophysics of Galaxies · Physics 2021-02-24 John Arban Lewis , Charles Lada , John Bieging , Anoush Kazarians , João Alves , Marco Lombardi

Recent observations with the Submillimeter Wave Astronomy Satellite indicate abundances of gaseous H2O and O2 in dense molecular clouds which are significantly lower than found in standard homogeneous chemistry models. We present here…

Astrophysics · Physics 2009-10-31 Marco Spaans , Ewine van Dishoeck

Methods: 12CO emission is imaged in position and position-velocity space analyzed statistically, and then compared with maps of total reddening and with models of the C+ - CO transition in H2-bearing diffuse clouds. Results: Around Zeta…

Astrophysics of Galaxies · Physics 2015-05-13 H. S. Liszt , J. Pety , K. Tachihara

We report the first uniform and systematic study of dust and molecular gas in nearby molecular clouds. We use surveys of dust extinction and emission to determine the opacity and map the distribution of the dust within a dozen local clouds…

Astrophysics of Galaxies · Physics 2022-05-25 John Arban Lewis , Charles J. Lada , Thomas Dame

The relative abundances of atomic and molecular species in planet-forming disks around young stars provide important constraints on photochemical disk models and provide a baseline for calculating disk masses from measurements of trace…

Solar and Stellar Astrophysics · Physics 2015-06-22 Kevin France , Gregory J. Herczeg , Matthew McJunkin , Steven V. Penton

We present Herschel/HIFI observations of nine transitions of \hho and \hheo towards six high-mass star-forming regions, obtained as part of the PRISMAS Key Program. Water vapor in translucent clouds is detected in absorption along every…

We present observations of the CO isotopologues ($^{12}$CO, $^{13}$CO, and C$^{18}$O) toward the Galactic region with $169\arcdeg.75 \leqslant l \leqslant 174\arcdeg.75$ and $-0\arcdeg.75 \leqslant b \leqslant 0\arcdeg.5$, using the Purple…

Astrophysics of Galaxies · Physics 2019-08-22 Fang Xiong , Xuepeng Chen , Qizhou Zhang , Ji Yang , Min Fang , Miaomiao Zhang , Weihua Guo , Li Sun

Carbon monoxide (CO) is a poor tracer of H$_{2}$ in the diffuse interstellar medium (ISM), where most of the carbon is not incorporated into CO molecules unlike the situation at higher extinctions. We present a novel, indirect method to…

Astrophysics of Galaxies · Physics 2023-12-18 Raphael Skalidis , Paul F. Goldsmith , Philip F. Hopkins , Sam B. Ponnada

12CO 1-0,2-1,4-3,7-6, and 13CO 1-0, 2-1, and 3-2 line was mapped with angular resolutions of 13" - 22" toward the nuclear region of starburst galaxy M82. The difference of lobe spacings in submillimeter (~15") and millimeter (~26") lines…

In the Halo21 absorption modeling challenge we generated synthetic absorption spectra of the circumgalactic medium (CGM), and attempted to estimate the metallicity, temperature, and density (Z, T, and nH) of the underlying gas using…

‹ Prev 1 3 4 5 6 7 10 Next ›