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The rate of ionization by cosmic rays in interstellar gas directly associated with gamma-ray emitting supernova remnants is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of…

Astrophysics of Galaxies · Physics 2015-05-28 J. K. Becker , J. H. Black , M. Safarzadeh , F. Schuppan

The molecular gas in the Central Molecular Zone (CMZ) of the Galaxy has been studied using infrared absorption spectra of H$_3^+$ lines at 3.5-4.0 $\mu$m and CO lines near 2.34 $\mu$m. In addition to the previously reported spectra of these…

High Energy Astrophysical Phenomena · Physics 2019-10-14 Takeshi Oka , T. R. Geballe , Miwa Goto , Tomonori Usuda , Benjamin , J. McCall , Nick Indriolo

Where dust and gas are uniformly mixed, atomic hydrogen can be traced through the detection of far-infrared (FIR) or UV emission of dust. We considered, for the origin of discrepancies observed between various direct and indirect tracers of…

Astrophysics of Galaxies · Physics 2022-11-30 Jean-Marc Casandjian , Jean Ballet , Isabelle Grenier , Quentin Remy

We have revisited the chemistry of chlorine-bearing species in the diffuse interstellar medium with new observations of the HCl$^+$ molecular ion and new astrochemical models. Using the GREAT instrument on board SOFIA, we observed the…

(abridged) We have mapped the prestellar core H-MM1 in Ophiuchus in rotational lines of ortho-H2D+ (oH2D+), N2H+, and DCO+ at the wavelength 0.8 mm with the Large APEX sub-Millimeter Array (LAsMA) multibeam receiver of the Atacama…

The excitation temperature T_01 derived from the relative intensities of the J = 0 (para) and J = 1 (ortho) rotational levels of H2 has been assumed to be an accurate measure of the kinetic temperature in interstellar environments. In…

Astrophysics of Galaxies · Physics 2015-05-27 Kyle N. Crabtree , Nick Indriolo , Holger Kreckel , Brian A. Tom , Benjamin J. McCall

We report on the detection with the HIFI instrument on board the Herschel satellite of the two hydrogen chloride isotopologues, H35Cl and H37Cl, towards the massive star-forming region W3A. The J=1-0 line of both species was observed with…

We present a comprehensive examination of interstellar P and Cl abundances based on an analysis of archival spectra acquired with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope and the Far Ultraviolet Spectroscopic…

Astrophysics of Galaxies · Physics 2023-05-30 Adam M. Ritchey , J. M. Brown , S. R. Federman , Paule Sonnentrucker

(Abridged) We present Herschel/HIFI spectra of the H2O 1113 GHz and H2O+ 1115 GHz lines toward five nearby prototypical starburst/AGN systems, and OH+ 971 GHz spectra toward three of these. The beam size of 20" corresponds to resolutions…

Astrophysics of Galaxies · Physics 2016-09-14 Floris van der Tak , Axel Weiss , Lijie Liu , Rolf Guesten

We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution $HST$/STIS UV and high-S/N optical spectra of the moderately reddened B3-5~V star HD~62542. This remarkable sight line exhibits both very…

Astrophysics of Galaxies · Physics 2020-07-08 Daniel E. Welty , Paule Sonnentrucker , Theodore P. Snow , Donald G. York

Low-energy cosmic rays are a fundamental source of ionization for molecular clouds, influencing their chemical, thermal and dynamical evolution. The purpose of this work is to explore the possibility that a low-energy component of…

Solar and Stellar Astrophysics · Physics 2015-05-13 Marco Padovani , Daniele Galli , Alfred E. Glassgold

Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\gamma$-ray flux produced by…

High Energy Astrophysical Phenomena · Physics 2015-09-18 G. Morlino , S. Gabici , J. Krause

Up to now, mostly relatively simple molecules have been detected in interstellar diffuse molecular clouds in our galaxy, but more complex species have been reported in the diffuse/translucent medium of a z = 0.89 spiral galaxy. We aim at…

Astrophysics of Galaxies · Physics 2017-09-20 V. Thiel , A. Belloche , K. M. Menten , R. T. Garrod , H. S. P. Müller

We carried out survey observations of HC$_{3}$N and HC$_{5}$N in the 42$-$45 GHz band toward 17 high-mass starless cores (HMSCs) and 35 high-mass protostellar objects (HMPOs) with the Nobeyama 45 m radio telescope. We have detected…

Astrophysics of Galaxies · Physics 2018-02-28 Kotomi Taniguchi , Masao Saito , T. K. Sridharan , Tetsuhiro Minamidani

We present the results of two Mopra 3-mm spectral line surveys of the Lines of Sight (LOS) toward the Galactic Center (GC) molecular complexes Sgr B2 (LOS+0.693) and Sgr A (LOS-0.11). The spectra covered the frequency ranges of ~77-93 GHz…

Astrophysics of Galaxies · Physics 2015-06-23 J. Armijos-Abendaño , J. Martín-Pintado , M. A. Requena-Torres , S. Martín , A. Rodríguez-Franco

Low-energy cosmic rays ($<1$ TeV) are a pivotal source of ionisation of the interstellar medium, where they play a central role in determining the gas chemical composition and drastically influence the formation of stars and planets. Over…

Astrophysics of Galaxies · Physics 2023-05-05 Giovanni Sabatini , Stefano Bovino , Elena Redaelli

We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these…

A high latitude HI 21 cm-line absorption survey toward extragalactic sources was recently completed using the Giant Meterwave Radio Telescope (GMRT). A total of 104 sources with mod(b) > 15 deg. and with a 21 cm flux density greater than 1…

Astrophysics · Physics 2007-05-23 K. S. Dwarakanath

The intermittent dissipation of interstellar turbulence is an important energy source in the diffuse ISM. Though on average smaller than the heating rates due to cosmic rays and the photoelectric effect on dust grains, the turbulent cascade…

Astrophysics of Galaxies · Physics 2015-09-11 Andrew Myers , Christopher McKee , Pak Shing Li

We present a catalogue of molecular cloud cores drawn from high latitude, medium opacity clouds, using the all-sky IRAS Sky Survey Atlas (ISSA) images at 60 and 100~$\mu$m. The typical column densities of the cores are $ N(H_2)\sim 3.8…

Astrophysics · Physics 2009-10-31 N. E. Jessop , D. Ward-Thompson
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