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相关论文: The CO-H2 conversion factor of diffuse ISM: Bright…

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Planck cold clumps are among the most promising objects to investigate the initial conditions of the evolution of molecular clouds. In this work, by combing the dust emission data from the survey of Planck satellite with the molecular data…

太阳与恒星天体物理 · 物理学 2013-10-11 Tie Liu , Yuefang Wu , Huawei Zhang

Observational evidence seems to indicate that the depletion of interstellar carbon into dust shows rather wide variations and that carbon undergoes rather rapid recycling in the interstellar medium (ISM). Small hydrocarbon grains are…

We present the analysis of a sub-DLA system (log N(H^0)=20.0+/-0.15, z_abs=2.69) toward SDSS J123714+064759 (z_em=2.78). Using the VLT/UVES and X-shooter spectrographs, we detect H2, HD and CO molecules in absorption with log…

宇宙学与河外天体物理 · 物理学 2015-05-19 P. Noterdaeme , P. Petitjean , C. Ledoux , S. Lopez , R. Srianand , S. D. Vergani

The rotational transitions of carbon monoxide (CO) are the primary means of investigating the density and velocity structure of the molecular interstellar medium. Here we study the lowest four rotational transitions of CO towards…

天体物理学 · 物理学 2009-10-31 James G. Ingalls , T. M. Bania , Adair P. Lane , Matthias Rumitz , Antony A. Stark

This study is aimed to contribute to a more comprehensive understanding of the molecular hydrogen distribution in the galaxy M33 by introducing novel methods for generating high angular resolution (18.2$''$, equivalent to 75 pc) column…

The transition between atomic and molecular hydrogen is associated with important changes in the structure of interstellar clouds, and marks the beginning of interstellar chemistry. Because of the relatively simple networks controlling…

星系天体物理 · 物理学 2019-01-30 M. Gerin , H. Liszt , D. Neufeld , B. Godard , P. Sonnentrucker , J. Pety , E. Roueff

We utilize a modified astrochemistry code which includes cosmic ray attenuation in-situ to quantify the impact of different cosmic-ray models on the CO-to-H$_2$ and CI-to-H$_2$ conversion factors, $X_{\rm CO}$ and $X_{\rm CI}$,…

星系天体物理 · 物理学 2019-10-09 Brandt A. L. Gaches , Stella S. R. Offner , Thomas G. Bisbas

Deep Herschel imaging and 12CO(2-1) line luminosities from the IRAM PdBI are combined for a sample of 17 galaxies at z>1 from the GOODS-N field. The sample includes galaxies both on and above the main sequence (MS) traced by star-forming…

We observed $\lambda$3mm \cotw, \coth, \coei, \hcop, HCN and CS emission from diffuse molecular gas along sightlines with \EBV\ $\approx$ 0.1 - 1 mag. Directions were mostly chosen for their proximity to sightlines toward background mm-wave…

星系天体物理 · 物理学 2020-07-15 Harvey S Liszt

We present a deep spectroscopic search for CO emission in the dwarf irregular galaxy DDO154, which has an Oxygen abundance of only 1/20 the solar value. The observations were conducted in order to constrain the CO-to-$\mathrm{H_2}$…

宇宙学与河外天体物理 · 物理学 2015-05-20 Shinya Komugi , Chikako Yasui , Naoto Kobayashi , Bunyo Hatsukade , Kotaro Kohno , Yoshiaki Sofue , Shiori Kyu

We modelled \HH\ and CO formation incorporating the fractionation and selective photodissociation affecting CO when \AV\ $\la2$mag. UV absorption measurements typically have N(\cotw)/N(\coth) $\approx 65$ that are reproduced with the…

星系天体物理 · 物理学 2017-02-01 Harvey S. Liszt

We present an analysis of CO molecular gas tracers in a sample of 500{\mu}m-selected Herschel-ATLAS galaxies at z<0.05 (cz<14990km/s). Using 22-500{\mu}m photometry from WISE, IRAS and Herschel, with HI data from the literature, we…

The [CII] 157.74 $\mu$m fine structure transition is one of the brightest and most well-studied emission lines in the far-infrared (FIR), produced in the interstellar medium (ISM) of galaxies. We study its properties in sub-pc resolution…

星系天体物理 · 物理学 2024-03-05 Alon Gurman , Chia-Yu Hu , Amiel Sternberg , Ewine F. van Dishoeck

A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\sim$ 0.5 arc min resolution. The same region was also surveyed in the…

星系天体物理 · 物理学 2015-05-27 S. Kong , C. J. Lada , E. A. Lada , C. Román-Zúñiga , J. H. Bieging , M. Lombardi , J. Forbrich , J. F. Alves

We report CO detections in 17 out of 19 infrared ultraluminous QSO (IR QSO) hosts observed with the IRAM 30m telescope. The cold molecular gas reservoir in these objects is in a range of 0.2--2.1$\times 10^{10}M_\odot$ (adopting a…

宇宙学与河外天体物理 · 物理学 2015-06-04 X. Y. Xia , Y. Gao , C. -N. Hao , Q. H. Tan , S. Mao , A. Omont , B. O. Flaquer , S. Leon , P. Cox

Context: We investigated the molecular gas associated with 6.7 GHz methanol masers throughout the Galaxy using a J=1-0 transition of the CO isotopologues. Methods:Using the 13.7-meter telescope at the Purple Mountain Observatory (PMO), we…

太阳与恒星天体物理 · 物理学 2014-09-05 Zhiyuan Ren , Yuefang Wu , Tie Liu , Lixin Li , Di Li , Binggang Ju

We observed a 10x20 pc region of the molecular cloud M17 in the 12CO and 13CO J=3-2 and J=2-1 transitions to determine their global behavior and to assess the reliability of using ratios of CO line intensities integrated over an entire…

天体物理学 · 物理学 2009-10-31 C. D. Wilson , J. E. Howe , M. L. Balogh

We present a new survey for CO in dwarf galaxies using the Kitt Peak 12m telescope. We observed the central regions of 121 northern dwarfs with IRAS detections and no known CO emission. We detect CO in 28 of these galaxies and marginally…

天体物理学 · 物理学 2009-11-10 Adam Leroy , Alberto D. Bolatto , Joshua D. Simon , Leo Blitz

The specific star-formation rate of star-forming `main sequence' galaxies significantly decreased since z~1.5, due to the decreasing molecular gas fraction and star formation efficiency. However, the radio-infrared (IR) correlation has not…

星系天体物理 · 物理学 2025-01-29 B. Vollmer , J. Freundlich , P. Gratier , Th. Lizee , M. Lendrin , J. Braine , M. Soida

Determining temperatures in molecular clouds from ratios of CO rotational lines or from ratios of continuum emission in different wavelength bands suffers from reduced temperature sensitivity in the high-temperature limit. In theory, the…

天体物理学 · 物理学 2008-11-26 W. F. Wall
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