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Title: Study of the Cosmic Rays and Interstellar Medium in Local H I Clouds Using Fermi-LAT Gamma-Ray Observations

Journal Article · · The Astrophysical Journal (Online)
ORCiD logo [1];  [1];  [2]; ORCiD logo [2];  [1]; ORCiD logo [2]; ORCiD logo [3];  [2]
  1. Hiroshima Univ. (Japan)
  2. Nagoya Univ. (Japan)
  3. Nagoya Univ. (Japan); SLAC National Accelerator Lab., Menlo Park, CA (United States)
+ Show Author Affiliations

An accurate estimate of the interstellar gas density distribution is crucial to understanding the interstellar medium (ISM) and Galactic cosmic rays (CRs). To comprehend the ISM and CRs in a local environment, a study of the diffuse $$γ$$-ray emission in a midlatitude region of the third quadrant was performed. Specifically, the $$γ$$-ray data in the 0.1–25.6 GeV energy range of the Fermi Large Area Telescope (LAT) and other interstellar gas tracers such as the HI4PI survey data and the Planck dust thermal emission model were used, and the northern and southern regions were analyzed separately. The variation of the dust emission Dem with the total neutral gas column density NH was studied in high dust temperature areas, and the NH/Dem ratio was calibrated using $$γ$$-ray data under the assumption of a uniform CR intensity in the studied regions. The measured integrated $$γ$$-ray emissivities above 100 MeV are (1.58 ± 0.04) x 10-26 photons s-1 sr-1H-atom-1 and (1.59 ± 0.02) x 10-26 photons s-1 sr-1 H-atom-1 in the northern and southern regions, respectively, supporting the existence of a uniform CR intensity in the vicinity of the solar system. While most of the gas can be interpreted to be H I with a spin temperature of TS = 125 K or higher, an area dominated by optically thick H I with TS ~ 40 K was identified.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
Agenzia Spaziale Italiana; Agenzia Spaziale Italiana (ASI); Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules (CNRS/IN2P3); Commissariat à l’Energie Atomique; Core of Research for the Energetic Universe at Hiroshima University; High Energy Accelerator Research Organization (KEK); Istituto Nazionale di Fisica Nucleare (INFN); Japan Aerospace Exploration Agency (JAXA); K. A. Wallenberg Foundation; Ministry of Education, Culture, Sports, Science and Technology (MEXT); National Aeronautics and Space Administration (NASA); Swedish National Space Board (SNSB); Swedish Research Council (VR); USDOE
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1617048
Journal Information:
The Astrophysical Journal (Online), Journal Name: The Astrophysical Journal (Online) Journal Issue: 2 Vol. 890; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English

References (47)

Nuclear enhancement factor in calculation of Galactic diffuse gamma-rays: A new estimate with DPMJET-3 journal June 2009
Planck early results. XIX. All-sky temperature and dust optical depth from Planck and IRAS. Constraints on the “dark gas” in our Galaxy journal December 2011
Planck 2013 results. XIII. Galactic CO emission journal October 2014
The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point journal October 2013
Planck 2013 results. XI. All-sky model of thermal dust emission journal October 2014
Planck intermediate results : XXVIII. Interstellar gas and dust in the Chamaeleon clouds as seen by journal September 2015
Dust variations in the diffuse interstellar medium: constraints on Milky Way dust from Planck -HFI observations journal May 2015
Dust evolution in the transition towards the denser ISM: impact on dust temperature, opacity, and spectral index journal June 2015
HI4PI: a full-sky H i survey based on EBHIS and GASS journal October 2016
Cosmic rays, gas and dust in nearby anticentre clouds: I. CO-to-H journal May 2017
Revisiting the radial distribution of pulsars in the Galaxy journal July 2004
A survey of interstellar H I from L-alpha absorption measurements. II journal August 1978
The Likelihood Analysis of EGRET Data journal April 1996
A New Σ‐ D Relation and Its Application to the Galactic Supernova Remnant Distribution journal September 1998
Propagation of Cosmic‐Ray Nucleons in the Galaxy journal December 1998
The Milky Way in Molecular Clouds: A New Complete CO Survey journal February 2001
Distances and Metallicities of High‐ and Intermediate‐Velocity Clouds journal October 2001
A Full‐Sky Hα Template for Microwave Foreground Prediction journal June 2003
HEALPix: A Framework for High‐Resolution Discretization and Fast Analysis of Data Distributed on the Sphere journal April 2005
Attenuation of Very High Energy Gamma Rays by the Milky Way Interstellar Radiation Field journal March 2006
Inverse Compton Origin of the Hard X‐Ray and Soft Gamma‐Ray Emission from the Galactic Ridge journal July 2008
THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION journal May 2009
FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS journal September 2009
FERMI OBSERVATIONS OF CASSIOPEIA AND CEPHEUS: DIFFUSE GAMMA-RAY EMISSION IN THE OUTER GALAXY journal January 2010
CONSTRAINTS ON THE COSMIC-RAY DENSITY GRADIENT BEYOND THE SOLAR CIRCLE FROM FERMI γ-RAY OBSERVATIONS OF THE THIRD GALACTIC QUADRANT journal December 2010
FERMI LARGE AREA TELESCOPE OBSERVATIONS OF TWO GAMMA-RAY EMISSION COMPONENTS FROM THE QUIESCENT SUN journal June 2011
FERMI -LAT OBSERVATIONS OF THE DIFFUSE γ-RAY EMISSION: IMPLICATIONS FOR COSMIC RAYS AND THE INTERSTELLAR MEDIUM journal April 2012
FERMI LARGE AREA TELESCOPE STUDY OF COSMIC RAYS AND THE INTERSTELLAR MEDIUM IN NEARBY MOLECULAR CLOUDS journal July 2012
GAMMA-RAY OBSERVATIONS OF THE ORION MOLECULAR CLOUDS WITH THE FERMI LARGE AREA TELESCOPE journal August 2012
Changes of dust Opacity with Density in the Orion a Molecular Cloud journal January 2013
Optically Thick h i Dominant in the Local Interstellar Medium: an Alternative Interpretation to “Dark gas” journal December 2014
LOCAL H i EMISSIVITY MEASURED WITH FERMI -LAT AND IMPLICATIONS FOR COSMIC-RAY SPECTRA journal June 2015
Nested Shells Reveal the Rejuvenation of the Orion–Eridanus Superbubble journal July 2015
THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE journal August 2015
NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE ( WMAP ) OBSERVATIONS: FINAL MAPS AND RESULTS journal September 2013
FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG journal June 2015
CO-dark gas and molecular filaments in Milky Way-type galaxies journal May 2014
Imprints of cosmic rays in multifrequency observations of the interstellar emission journal December 2017
Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope journal April 2016
Probing local cosmic rays using Fermi-LAT observations of a mid-latitude region in the third Galactic quadrant journal June 2019
The interstellar environment of our galaxy journal December 2001
The Parkes Multibeam Pulsar Survey - VI. Discovery and timing of 142 pulsars and a Galactic population analysis journal October 2006
Unveiling Extensive Clouds of Dark Gas in the Solar Neighborhood journal February 2005
The Nine Lives of Cosmic Rays in Galaxies journal August 2015
H I in the Galaxy journal September 1990
Cosmic-Ray Propagation and Interactions in the Galaxy journal November 2007
QUANTIFYING THE INTERSTELLAR MEDIUM AND COSMIC RAYS IN THE MBM 53, 54, AND 55 MOLECULAR CLOUDS AND THE PEGASUS LOOP USING FERMI -LAT GAMMA-RAY OBSERVATIONS journal December 2016

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79 ASTRONOMY AND ASTROPHYSICS
Galactic cosmic rays
Gamma-rays
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