Fermi observations of Cassiopeia and Cepheus: diffuse gamma-ray emission in the outer Galaxy

A. A. Abdo; M. Ackermann; M. Ajello; L. Baldini; Jean Ballet; G. Barbiellini; D. Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; B. Berenji; E. D. Bloom; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; Pascal Bruel; T. H. Burnett; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; Ö. Çelik; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; C. D. Dermer; F. de Palma; S. W. Digel; E. Do Couto e Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; W. B. Focke; P. Fortin; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; N. Gehrels; S. Germani; G. Giavitto; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; A. K. Harding; M. Hayashida; D. Horan; R. E. Hughes; M. S. Jackson; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; Jürgen Knödlseder; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; J. E. Mcenery; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; A. Okumura; N. Omodei; E. Orlando; J. F. Ormes; D. Paneque; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rainò; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; A. Y. Rodriguez; F. Ryde; H. F.-W. Sadrozinski; D. Sanchez; A. Sander; P. M. Saz Parkinson; C. Sgrò; E. J. Siskind; P. D. Smith; G. Spandre; P. Spinelli; Jean-Luc Starck; M. S. Strickman; A. W. Strong; D. J. Suson; H. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; V. Vasileiou; N. Vilchez; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; T. Ylinen; M. Ziegler

doi:10.1088/0004-637X/710/1/133

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Fermi observations of Cassiopeia and Cepheus: diffuse gamma-ray emission in the outer Galaxy

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Fermi observations of Cassiopeia and Cepheus: diffuse gamma-ray emission in the outer Galaxy

A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, Jean Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, …

The Astrophysical Journal, Vol.710, pp.133-149

10/02/2010

DOI: https://doi.org/10.1088/0004-637X/710/1/133

Abstract

cosmic rays

gamma rays: diffuse background

ISM: clouds

We present the analysis of the interstellar gamma-ray emission measured by the Fermi Large Area Telescope toward a region in the second Galactic quadrant at 100 deg < l < 145 deg and -15 deg < b < +30 deg. This region encompasses the prominent Gould-Belt clouds of Cassiopeia, Cepheus and the Polaris flare, as well as atomic and molecular complexes at larger distances, like that associated with NGC 7538 in the Perseus arm. The good kinematic separation in velocity between the local, Perseus, and outer arms, and the presence of massive complexes in each of them make this region well suited to probe cosmic rays and the interstellar medium beyond the solar circle. The gamma-ray emissivity spectrum of the gas in the Gould Belt is consistent with expectations based on the locally measured cosmic-ray spectra. The gamma-ray emissivity decreases from the Gould Belt to the Perseus arm, but the measured gradient is flatter than expectations for cosmic-ray sources peaking in the inner Galaxy as suggested by pulsars. The Xco=N(H2)/W(CO) conversion factor is found to increase from (0.87 +- 0.05) 10^20 cm^-2 (K km s^-1)^-1 in the Gould Belt to (1.9 +- 0.2) 10^20 cm^-2 (K km s^-1)^-1 in the Perseus arm. We derive masses for the molecular clouds under study. Dark gas, not properly traced by radio and microwave surveys, is detected in the Gould Belt through a correlated excess of dust and gamma-ray emission: its mass amounts to ~50% of the CO-traced mass.

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Title: Fermi observations of Cassiopeia and Cepheus: diffuse gamma-ray emission in the outer Galaxy
Creators - without role: A. A. Abdo - United States Naval Research Laboratory
M. Ackermann - Kavli Institute for Particle Astrophysics and Cosmology
M. Ajello - Kavli Institute for Particle Astrophysics and Cosmology
L. Baldini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
Jean Ballet - Astrophysique, Instrumentation et Modélisation
G. Barbiellini - University of Trieste
D. Bastieri - University of Padua
B. M. Baughman - The Ohio State University
K. Bechtol - Kavli Institute for Particle Astrophysics and Cosmology
R. Bellazzini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
B. Berenji - Kavli Institute for Particle Astrophysics and Cosmology
E. D. Bloom - Kavli Institute for Particle Astrophysics and Cosmology
E. Bonamente - University of Perugia
A. W. Borgland - Stanford University
J. Bregeon - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
A. Brez - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Brigida - Polytechnic University of Bari
Pascal Bruel - École Polytechnique
T. H. Burnett - University of Washington
S. Buson - University of Padua
G. A. Caliandro - Institute of Space Sciences
R. A. Cameron - Stanford University
P. A. Caraveo - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
J. M. Casandjian - Université Paris Cité
C. Cecchi - University of Perugia
Ö. Çelik - Goddard Space Flight Center
A. Chekhtman - United States Naval Research Laboratory
C. C. Cheung - United States Naval Research Laboratory
J. Chiang - Kavli Institute for Particle Astrophysics and Cosmology
S. Ciprini - University of Perugia
R. Claus - Kavli Institute for Particle Astrophysics and Cosmology
J. Cohen-Tanugi - Institut National de Physique Nucléaire et de Physique des Particules
L. R. Cominsky - Sonoma State University
J. Conrad - Stockholm University
C. D. Dermer - United States Naval Research Laboratory
F. de Palma - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
S. W. Digel - Kavli Institute for Particle Astrophysics and Cosmology
E. Do Couto e Silva
P. S. Drell - Kavli Institute for Particle Astrophysics and Cosmology
R. Dubois - Kavli Institute for Particle Astrophysics and Cosmology
D. Dumora - Laboratoire de Physique des deux infinis Bordeaux
C. Farnier - Laboratoire de Physique Théorique
C. Favuzzi - Polytechnic University of Bari
S. J. Fegan - Laboratoire Leprince-Ringuet
W. B. Focke - SLAC National Accelerator Laboratory
P. Fortin - Centre National de la Recherche Scientifique
M. Frailis - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
Y. Fukazawa - Hiroshima University
S. Funk - Stanford University
P. Fusco - Polytechnic University of Bari
F. Gargano - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
N. Gehrels - Goddard Space Flight Center
S. Germani - University of Perugia
G. Giavitto - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
B. Giebels - Laboratoire Leprince-Ringuet
N. Giglietto - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
F. Giordano - Polytechnic University of Bari
T. Glanzman - Stanford University
G. Godfrey - Kavli Institute for Particle Astrophysics and Cosmology
I. A. Grenier - CEA Paris-Saclay
M.-H. Grondin - Université de Bordeaux
J. E. Grove - United States Naval Research Laboratory
L. Guillemot - Laboratoire de Physique des deux infinis Bordeaux
S. Guiriec - University of Alabama in Huntsville
A. K. Harding - Goddard Space Flight Center
M. Hayashida - Kavli Institute for Particle Astrophysics and Cosmology
D. Horan - Laboratoire Leprince-Ringuet
R. E. Hughes - The Ohio State University
M. S. Jackson - KTH Royal Institute of Technology
G. Jóhannesson - Kavli Institute for Particle Astrophysics and Cosmology
A. S. Johnson - SLAC National Accelerator Laboratory
W. N. Johnson - United States Naval Research Laboratory
T. Kamae - SLAC National Accelerator Laboratory
H. Katagiri - Hiroshima University
J. Kataoka - Waseda University
N. Kawai - RIKEN
M. Kerr - University of Washington
Jürgen Knödlseder - Centre National d'Études Spatiales
M. Kuss - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
J. Lande - Kavli Institute for Particle Astrophysics and Cosmology
L. Latronico - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Lemoine-Goumard - Université de Bordeaux
F. Longo - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
F. Loparco - Polytechnic University of Bari
B. Lott - Laboratoire de Physique des deux infinis Bordeaux
M. N. Lovellette - United States Naval Research Laboratory
P. Lubrano - University of Perugia
A. Makeev - United States Naval Research Laboratory
M. N. Mazziotta - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
J. E. Mcenery - University of Maryland, College Park
C. Meurer - AlbaNova
P. F. Michelson - Kavli Institute for Particle Astrophysics and Cosmology
W. Mitthumsiri - Kavli Institute for Particle Astrophysics and Cosmology
T. Mizuno - Hiroshima University
C. Monte - Polytechnic University of Bari
M. E. Monzani - Kavli Institute for Particle Astrophysics and Cosmology
A. Morselli - Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata
I. V. Moskalenko - Stanford University
S. Murgia - SLAC National Accelerator Laboratory
P. L. Nolan - Kavli Institute for Particle Astrophysics and Cosmology
J. P. Norris - University of Denver
E. Nuss - Laboratoire de Physique Théorique
T. Ohsugi - Hiroshima University
A. Okumura - The University of Tokyo
N. Omodei - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
E. Orlando - Max Planck Institute for Extraterrestrial Physics
J. F. Ormes - University of Denver
D. Paneque - Kavli Institute for Particle Astrophysics and Cosmology
V. Pelassa - Laboratoire de Physique Théorique
M. Pepe - University of Perugia
M. Pesce-Rollins - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
F. Piron - Laboratoire de Physique Théorique
T. A. Porter - University of California, Santa Cruz
S. Rainò - Polytechnic University of Bari
R. Rando - University of Padua
M. Razzano - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
A. Reimer - Kavli Institute for Particle Astrophysics and Cosmology
O. Reimer - Kavli Institute for Particle Astrophysics and Cosmology
T. Reposeur - Laboratoire de Physique des deux infinis Bordeaux
A. Y. Rodriguez - Institute of Space Sciences
F. Ryde - KTH Royal Institute of Technology
H. F.-W. Sadrozinski - University of California, Santa Cruz
D. Sanchez - Laboratoire Leprince-Ringuet
A. Sander - The Ohio State University
P. M. Saz Parkinson
C. Sgrò - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
E. J. Siskind - Real Time Tomography
P. D. Smith - The Ohio State University
G. Spandre - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. Spinelli - Polytechnic University of Bari
Jean-Luc Starck - Astrophysique Interprétation Modélisation
M. S. Strickman - United States Naval Research Laboratory
A. W. Strong - Max Planck Institute for Extraterrestrial Physics
D. J. Suson - Purdue University Northwest
H. Takahashi - Hiroshima University
T. Tanaka - Kavli Institute for Particle Astrophysics and Cosmology
J. B. Thayer - Stanford University
J. G. Thayer - SLAC National Accelerator Laboratory
D. J. Thompson - Goddard Space Flight Center
L. Tibaldo - CEA Paris-Saclay
D. F. Torres - Institució Catalana de Recerca i Estudis Avançats
G. Tosti - Istituto Nazionale di Fisica Nucleare, Sezione di Perugia
A. Tramacere - Consorzio Interuniversitario Fisica Spaziale
Y. Uchiyama - Kavli Institute for Particle Astrophysics and Cosmology
T. L. Usher - Kavli Institute for Particle Astrophysics and Cosmology
V. Vasileiou - Goddard Space Flight Center
N. Vilchez - Université Toulouse III - Paul Sabatier
V. Vitale - Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata
A. P. Waite - Kavli Institute for Particle Astrophysics and Cosmology
P. Wang - SLAC National Accelerator Laboratory
B. L. Winer - The Ohio State University
K. S. Wood - United States Naval Research Laboratory
T. Ylinen - Fraunhofer Chalmers Research Centre for Industrial Mathematics
M. Ziegler - University of California, Santa Cruz
Publication Details: The Astrophysical Journal, Vol.710, pp.133-149
Identifiers: 9941394209311
Academic Unit: Université de Montpellier
Language: English
Resource Type: Journal article
Local Fields: in2p3-00460710