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相关论文: The CO-to-H2 Conversion Factor

200 篇论文

We present radial profiles of surface brightness in UV and IR bands, estimate stellar mass surface density ($\Sigma_\star$) and star formation rate surface density ($\Sigma_\mathrm{SFR}$), and predict the CO-to-H$_2$ conversion factor…

We present and analyze deep Herschel/HIFI observations of the [CII] 158um, [CI] 609um, and [CI] 370um lines towards 54 lines-of-sight (LOS) in the Large and Small Magellanic clouds. These observations are used to determine the physical…

We acquired ALMA ground state absorption profiles of HCO+ and other molecules toward 33 extragalactic continuum sources seen toward the Galactic anticenter, deriving N(H2) = N(HCO+)/3x10^{-9}. We observed J=1-0 CO emission with the IRAM 30m…

星系天体物理 · 物理学 2023-07-19 Harvey Liszt , Maryvonne Gerin

Estimating molecular abundances ratios from the direct measurement of the emission of the molecules towards a variety of interstellar environments is indeed very useful to advance in our understanding of the chemical evolution of the…

星系天体物理 · 物理学 2018-09-12 S. Paron , M. B. Areal , M. E. Ortega

We present a study of the $^{12}$CO(1-0) line emission anisotropy across the Milky Way's disk to examine the effect of stellar feedback and Galactic dynamics on the distribution of the dense interstellar medium. The Hessian matrix method is…

[Abridged] The [CII] 158um line is an important tool for understanding the life cycle of interstellar matter. Ionized carbon is present in a variety of phases of the interstellar medium, including the diffuse ionized medium, warm and cold…

星系天体物理 · 物理学 2015-06-15 Jorge L. Pineda , William D. Langer , Thangasamy Velusamy , Paul F. Goldsmith

Carbon dioxide (CO$_2$) is one of the most important interstellar molecules. While it is considered that it forms on the surface of interstellar dust grains, the exact contribution of different chemical mechanisms is still poorly…

CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many…

地球与行星天体物理 · 物理学 2019-10-02 Ke Zhang , Edwin A. Bergin , Kamber R. Schwarz , Sebastiaan Krijt , Fred Ciesla

Nearby dwarf irregular galaxies are ideal laboratories for studying the interstellar medium (ISM) at low metallicity, which is expected to be common for galaxies at very high redshift being observed by the James Webb Space Telescope. We…

星系天体物理 · 物理学 2023-08-02 Chia-Yu Hu , Amiel Sternberg , Ewine F. van Dishoeck

We use the IRAM HERACLES survey to study CO emission from 33 nearby spiral galaxies down to very low intensities. Using atomic hydrogen (HI) data, mostly from THINGS, we predict the local mean CO velocity from the mean HI velocity. By…

We present the first statistical survey of the properties of the 12CO(1-0) and 12CO(3-2) line emission from the nuclei of a nearly complete subsample of 60 infrared (IR) luminous galaxies selected from SCUBA Local Universe Galaxy Survey…

天体物理学 · 物理学 2009-11-07 Lihong Yao , E. R. Seaquist , Nario Kuno , Loretta Dunne

(abridged) In this work we have a closer look at the gas content or fraction and the associated star formation rate in main sequence and starburst galaxies at z=0 and z~1-2 by applying an analytical model of galactic clumpy gas disks to…

星系天体物理 · 物理学 2017-06-28 B. Vollmer , P. Gratier , J. Braine , C. Bot

To understand the impact of low metallicities on giant molecular cloud (GMC) structure, we compare far infrared dust emission, CO emission, and dynamics in the star-forming complex N83 in the Wing of the Small Magellanic Cloud. Dust…

宇宙学与河外天体物理 · 物理学 2009-08-12 A. K. Leroy , A. Bolatto , C. Bot , C. W. Engelbracht , K. Gordon , F. P. Israel , M. Rubio , K. Sandstrom , S. Stanimirović

In this review, I discuss recent detailed studies of individual molecular clouds in M33 in higher rotational transitions of CO, 13CO, and the fine structure line of atomic carbon. These data reveal that the temperature and density of the…

天体物理学 · 物理学 2007-05-23 C. D. Wilson

Observations of submillimeter lines of CO (up to J=6-5), HCO+, HCN (up to J=4-3) and their isotopes from circumstellar disks around low mass pre-main sequence stars are presented. The different line ratios and optical depths indicate that…

天体物理学 · 物理学 2009-11-07 Gerd-Jan van Zadelhoff , Ewine F. van Dishoeck , Wing-Fai Thi , Geoffrey A. Blake

Carbon monoxide (CO) is the most abundant molecule after molecular hydrogen and is important for the chemistry in circumstellar envelopes around evolved stars. When modelling the strength and shape of molecular lines, the size of the CO…

太阳与恒星天体物理 · 物理学 2021-06-02 Martin Groenewegen , Maryam Saberi

We investigate the relationship between the dust-to-metals ratio (D/M) and the local interstellar medium environment at ~2 kpc resolution in five nearby galaxies: IC342, M31, M33, M101, and NGC628. A modified blackbody model with a broken…

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…

星系天体物理 · 物理学 2016-11-23 M. V. Kazandjian , I. Pelupessy , R. Meijerink , F. P. Israel , C. M. Coppola , M. J. F. Rosenberg , M. Spaans

We investigate interstellar absorption from molecular hydrogen (H_2) and metals in an intermediate-velocity cloud (IVC) in the direction of the LMC star Sk -68 80 (HD 36521), based on data from the Far Ultraviolet Spectroscopic Explorer…

天体物理学 · 物理学 2011-05-23 P. Richter , K. R. Sembach , J. C. Howk

CO is commonly used as a tracer of the total gas mass in both the interstellar medium and in protoplanetary disks. Recently there has been much debate about the utility of CO as a mass tracer in disks. Observations of CO in protoplanetary…

地球与行星天体物理 · 物理学 2018-04-11 Kamber R. Schwarz , Edwin A. Bergin , L. Ilsedore Cleeves , Ke Zhang , Karin I. Öberg , Geoffrey A. Blake , Dana Anderson