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Related papers: Distribution of Water Vapor in Molecular Clouds

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Within low-mass star formation, water vapor plays a key role in the chemistry and energy balance of the circumstellar material. The Herschel Space Observatory will open up the possibility to observe water lines originating from a wide range…

We compare the observational properties between $^{12}$CO, $^{13}$CO, and C$^{18}$O and summarize the observational parameters based on 7069 clouds sample from the Milky Way Imaging Scroll Painting (MWISP) CO survey in a section of the…

Astrophysics of Galaxies · Physics 2023-08-22 Chen Wang , Haoran Feng , Ji Yang , Xuepeng Chen , Yang Su , Qing-Zeng Yan , Fujun Du , Yuehui Ma , Jiajun Cai

We combine Herschel observations of a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the…

Astrophysics of Galaxies · Physics 2015-06-11 P. Sonnentrucker , M. Wolfire , D. A. Neufeld , N. Flagey , M. Gerin , P. Goldsmith , D. Lis , R. Monje

We report Submillimeter Array dust continuum and molecular spectral line observations toward the Orion Bar photon-dominated region (PDR). The 1.2 mm continuum map reveals, for the first time, a total of 9 compact (r < 0.01pc) dust…

Solar and Stellar Astrophysics · Physics 2018-03-08 Keping Qiu , Zeqiang Xie , Qizhou Zhang

Aims: Ices in dense star-forming cores contain the bulk of volatile molecules apart from H2 and thus represent a large fraction of dark cloud chemistry budget.To directly constrain the freeze-out profile of CO, the formation route of CO2…

Astrophysics · Physics 2009-11-11 K. M. Pontoppidan

The mass of molecular gas in an interstellar cloud is often measured using line emission from low rotational levels of CO, which are sensitive to the CO mass, and then scaling to the assumed molecular hydrogen H_2 mass. However, a…

Astrophysics of Galaxies · Physics 2015-05-18 Mark G. Wolfire , David Hollenbach , Christopher F. McKee

We have used the Odin submillimetre-wave satellite telescope to observe the ground state transitions of ortho-ammonia and ortho-water, including their 15N, 18O, and 17O isotopologues, towards Sgr B2. The extensive simultaneous velocity…

We conducted an exploration of 12CO molecular outflows in the Orion A giant molecular cloud to investigate outflow feedback using 12CO (J = 1-0) and 13CO (J = 1-0) data obtained by the Nobeyama 45-m telescope. In the region excluding the…

Dynamic models of M-type Mira variables predict the occurrence of water "shells", i.e. of zones of high H2O density and high H2O absorption inside the stellar atmosphere. The density, position and width of these shells is closely correlated…

Astrophysics · Physics 2016-08-16 A. Tej , A. Lançon , M. Scholz

We present the results of N2H+(1-0) observations of 35 dense molecular cloud cores from the northern and southern hemispheres where massive stars and star clusters are formed. Line emission has been detected in 33 sources, for 28 sources…

Astrophysics · Physics 2009-11-07 L. Pirogov , I. Zinchenko , P. Caselli , L. E. B. Johansson , P. C. Myers

We investigate the correlation between OH and H2 column densities in diffuse Galactic clouds, in order to identify potential molecular tracers of interstellar H2. For this, we analyse near-UV spectra extracted from the ESO/VLT archives…

Astrophysics of Galaxies · Physics 2023-06-09 Katherine Rawlins , Bhaswati Mookerjea

We recently reported a population of protostellar candidates in the 20 km s$^{-1}$ cloud in the Central Molecular Zone of the Milky Way, traced by H$_2$O masers in gravitationally bound dense cores. In this paper, we report…

We present hydrodynamical simulations of the photoevaporation of a cloud with large-scale density gradients, giving rise to an ionized, photoevaporation flow. The flow is found to be approximately steady during the large part of its…

Astrophysics · Physics 2009-11-11 W. J. Henney , S. J. Arthur , Ma. T. Garcia-Diaz

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…

Apart from being an important coolant, H2O is known to be a tracer of high-velocity molecular gas. Recent models predict relatively high abundances behind interstellar shockwaves. The dynamical and physical conditions of the H2O emitting…

The diffusion of atoms and molecules in ices covering dust grains in dense clouds in interstellar space is an important but poorly characterized step in the formation of complex molecules in space. Here we report the measurement of…

Instrumentation and Methods for Astrophysics · Physics 2018-08-29 Jiao He , SM Emtiaz , Gianfranco Vidali

(Abridged) We carried out a comprehensive far-ultraviolet (UV) survey of ^12CO and H_2 column densities along diffuse molecular Galactic sight lines in order to explore in detail the relationship between CO and H_2. We measured new CO…

Astrophysics · Physics 2009-11-13 Y. Sheffer , M. Rogers , S. R. Federman , N. P. Abel , R. Gredel , D. L. Lambert , G. Shaw

The diffusion of molecules on interstellar grain surfaces is one of the most important driving forces for the molecular complexity in the interstellar medium. Due to the lack of laboratory measurements, astrochemical modeling of grain…

Instrumentation and Methods for Astrophysics · Physics 2023-02-20 Jiao He , Paula Caroline Pérez Rickert , Tushar Suhasaria , Orianne Sohier , Tia Bäcker , Dimitra Demertzi , Gianfranco Vidali , Thomas K. Henning

Near ultraviolet observations of OH+ and OH in diffuse molecular clouds reveal a preference for different environments. The dominant absorption feature in OH+ arises from a main component seen in CH+ (that with the highest CH+/CH column…

Astrophysics of Galaxies · Physics 2015-06-18 A. J. Porras , S. R. Federman , D. E. Welty , A. M. Ritchey

We present high resolution maps ($\sim 2^{''}$) maps of the J=1-0 and J=2-1 transitions of C$^{18}$O in the central $\sim 150$ pc of the gas-rich nucleus of IC 342, made with the Owens Valley Millimeter Array. From the C$^{18}$O maps we are…

Astrophysics · Physics 2009-11-06 David S. Meier , Jean L. Turner