English
Related papers

Related papers: The C$^{14}$N/C$^{15}$N Ratio in Diffuse Molecular…

200 papers

We have studied 14 southern infrared dark clouds (IRDCs) using the data taken from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey and the GLIMPSE and MIPSGAL mid-infrared survey of the inner Galaxy. The physical and chemical…

Astrophysics of Galaxies · Physics 2015-06-12 Xiao-Lan Liu , Jun-Jie Wang , Jin-Long Xu

We present 21-cm absorption measurements towards 12 radio continuum sources with previously identified thermally-unstable warm neutral medium (WNM). These observations were obtained with the Expanded Very Large Array (EVLA) and were…

Astrophysics of Galaxies · Physics 2015-05-20 Ayesha Begum , Snezana Stanimirovic , W. M. Goss , Carl Heiles , Anthony S. Pavkovich , Patrick Hennebelle

Aims. The purpose of this study is to investigate the distributions of the isomeric molecules HCN and HNC and estimate their abundance ratio in the protostellar core Cha-MMS1 located in Chamaeleon {\sc i}. Methods. The core was mapped in…

Astrophysics · Physics 2009-11-11 P. P. Tennekes , J. Harju , M. Juvela , L. V. Toth

High-angular resolution observations of dense molecular cores show that these cores can be clumpier at smaller scales, and that some of these clumps can also be unbound or transient. The use of chemical models of the evolution of the…

Astrophysics of Galaxies · Physics 2015-06-05 Oscar Morata , Josep Miquel Girart , Robert Estalella , Robin T. Garrod

This paper reports the first measurements of solid-phase vacuum-ultraviolet (VUV) absorption cross-sections of heavy isotopologues present in icy dust grain mantles of dense interstellar clouds and cold circumstellar environments. Pure ices…

Solar and Stellar Astrophysics · Physics 2014-06-02 G. A. Cruz-Diaz , G. M. Muñoz Caro , Y. -J. Chen

Within a few parsecs around the central Black Hole Sgr A*, chemistry in the dense molecular cloud material of the circumnuclear disk (CND) can be affected by many energetic phenomena such as high UV-flux from the massive central star…

Context: An unexpectedly complex polyatomic chemistry exists in diffuse clouds, allowing detection of species such as C2H, C3H2, H2CO and NH3 which have relative abundances that are strikingly similar to those inferred toward the dark cloud…

Astrophysics of Galaxies · Physics 2009-01-21 H. S. Liszt , J. Pety , R. Lucas

We study a small sample of z=0.1-0.6 core-collapse supernova (CCSN) host galaxies. Continuum observations at 250GHz have been performed with MAMBO at the IRAM-30m telescope. None of these sources has been detected and the error-weighted…

Astrophysics · Physics 2009-11-13 A. -L. Melchior , F. Combes

Ultraviolet and optical spectra of interstellar gas along the lines of sight to nearby stars have been interpreted by Redfield & Linsky (2008) and previous studies as a set of discrete warm, partially ionized clouds each with a different…

Astrophysics of Galaxies · Physics 2015-10-21 Seth Redfield , Jeffrey L. Linsky

We derived the dust-to-HI ratio of the intermediate-velocity clouds (IVCs), the high-velocity clouds (HVCs), and the local HI gas, by carrying out a multiple-regression analysis of the 21cm HI emission combined with the sub-mm dust optical…

Astrophysics of Galaxies · Physics 2024-01-24 Takahiro Hayakawa , Yasuo Fukui

Chemistry in diffuse molecular clouds relies primarily on rapid ion-molecule reactions. Formation of the initial ions, H$^+$ and H$_2^+$, is dominated by cosmic-ray ionization of H and H$_2$, making the cosmic-ray ionization rate (denoted…

Determining the structure of and the velocity field in prestellar cores is essential to understanding protostellar evolution.} {We have observed the dense prestellar cores L 1544 and L 183 in the $N = 1 \to 0$ rotational transition of CN…

Astrophysics · Physics 2009-11-13 Pierre Hily-Blant , Malcolm Walmsley , G. Pineau Des Forêts , David Flower

We aim to determine the $^{14}$N/$^{15}$N and $^{12}$C/$^{13}$C ratios for HCN in six starless and prestellar cores and compare the results between the direct method using radiative transfer modeling and the indirect double isotope method…

Astrophysics of Galaxies · Physics 2024-03-08 S. S. Jensen , S. Spezzano , P. Caselli , O. Sipilä , E. Redaelli , K. Giers , J. Ferrer Asensio

We have obtained high resolution FUSE and HST/STIS echelle observations of the quasar PG 1116+215. The semi-continuous coverage of the ultraviolet spectrum over the wavelength range 916-2800 provides detections of Galactic and high velocity…

Astrophysics · Physics 2009-11-10 Rajib Ganguly , Kenneth R. Sembach , Todd M. Tripp , Blair D. Savage

UV absorption studies with FUSE have observed H2 molecular gas in translucent and diffuse clouds. Observations of the 158 micron [C II] fine structure line with Herschel also trace the same H2 molecular gas in emission. We present [C II]…

Astrophysics of Galaxies · Physics 2017-04-12 Thangasamy Velusamy , William Langer , Paul Goldsmith , Jorge L. Pineda

We carry out a systematic study of the density structure of gas in the Central Molecular Zone (CMZ) in the Galactic center by extracting clumps from the APEX Telescope Large Area Survey of the Galaxy survey at 870 $\mu$m. We find that the…

Astrophysics of Galaxies · Physics 2020-07-15 Guang-Xing Li , Chuan-Peng Zhang

We discuss the composition of dust and ice along the line of sight to the Galactic Center (GC) based on analysis of mid-infrared spectra (2.4-13 micron) from the Short Wavelength Spectrometer on the Infrared Space Observatory (ISO). We have…

We report the detection of absorption from interstellar C_2 and C_3 toward the moderately reddened star Sk 143, located in the near 'wing' region of the SMC, in optical spectra obtained with the ESO VLT/UVES. These detections of C_2…

Astrophysics of Galaxies · Physics 2015-06-11 Daniel E. Welty , J. Christopher Howk , Nicolas Lehner , John H. Black

Hydrocarbons are ubiquitous in the interstellar medium, observed in diverse environments ranging from diffuse to molecular dark clouds and strong photon-dominated regions near HII regions. Recently, two broad diffuse interstellar bands…

Astrophysics of Galaxies · Physics 2015-06-05 Harvey Liszt , Paule Sonnentrucker , Martin Cordiner , Maryvonne Gerin

The electron density ($n_{e^{-}}$) plays an important role in setting the chemistry and physics of the interstellar medium. However, measurements of $n_{e^{-}}$ in neutral clouds have been directly obtained only toward a few lines of sight…

Astrophysics of Galaxies · Physics 2021-07-16 P. Salas , M. R. Rugel , K. L. Emig , J. Kauffmann , K. M. Menten , F. Wyrowski , A. G. G. M. Tielens