FERMI LARGE AREA TELESCOPE STUDY OF COSMIC RAYS AND THE INTERSTELLAR MEDIUM IN NEARBY MOLECULAR CLOUDS

Markus Ackermann; Marco Ajello; A. Allafort; Luca Baldini; Jean Ballet; Guido Barbiellini; D. Bastieri; K. Bechtol; R. Bellazzini; B. Berenji; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; E. Bottacini; T. J. Brandt; J. Bregeon; M. Brigida; Pascal Bruel; R. Buehler; G. Busetto; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; E. Charles; A. Chekhtman; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; F. d'Ammando; A. de Angelis; F. de Palma; C. D. Dermer; S. W. Digel; E. Do Couto E Silva; P. S. Drell; A. Drlica-Wagner; L. Falletti; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; Y. Fukazawa; Y. Fukui; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; S. Guiriec; D. Hadasch; Y. Hanabata; A. K. Harding; K. Hayashi; D. Horan; X. Hou; R. E. Hughes; R. Itoh; M. S. Jackson; G. J'Ohannesson; A. S. Johnson; T. Kamae; H. Katagiri; J. Kataoka; Jürgen Knödlseder; M. Kuss; J. Lande; S. Larsson; H. Lee; M. Lemoine-Goumard; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; P. Martin; M. N. Mazziotta; J. E. Mcenery; J. Mehault; P. F. Michelson; W. Mitthumsir; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; M. Naumann-Godo; R. Nemmen; S. Nishino; J. P. Norris; E. Nuss; M. Ohno; T. Ohsugi; A. Okumura; N. Omode; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; J. H. Panetta; D. Parent; M. Pesce-Rollins; M. Pierbattista; F. Piron; G. Pivato; T.A. Porter; S. Rain'O; R. Rando; M. Razzano; A. Reimer; O. Reimer; C. Romoli; M. Rot; T. Sada; H. F.-W. Sadrozinski; D.A. Sanchez; C. Sbarra; C. Sgr'O; E. J. Siskind; G. Spandre; P. Spinelli; A. W. Strong; D. J. Suson; H. Takahashi; T. Takahashi; T. Tanaka; J. G. Thayer; J. B. Thayer; D. J. Thompson; L. Tibaldo; O. Tibolla; M. Tinivella; D. F. Torres; G. Tosti; A. Tramacer; E. Troja; Y. Uchiyama; T. Uehara; T. L. Usher; J. Vandenbroucke; V. Vasileiou; G. Vianello; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; H. Yamamoto; Z. Yang; D. S. Zimmer

doi:10.1088/0004-637X/755/1/22

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FERMI LARGE AREA TELESCOPE STUDY OF COSMIC RAYS AND THE INTERSTELLAR MEDIUM IN NEARBY MOLECULAR CLOUDS

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FERMI LARGE AREA TELESCOPE STUDY OF COSMIC RAYS AND THE INTERSTELLAR MEDIUM IN NEARBY MOLECULAR CLOUDS

Markus Ackermann, Marco Ajello, A. Allafort, Luca Baldini, Jean Ballet, Guido Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, …

The Astrophysical Journal, Vol.755

2012

DOI: https://doi.org/10.1088/0004-637X/755/1/22

Abstract

cosmic rays

gamma rays: ISM

We report an analysis of the interstellar γ -ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within ∼300 pc from the solar system. The γ -ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ -ray emissivities above 250 MeV are (5.9 ± 0.1stat +0.9 −1.0sys) × 10−27 photons s−1 sr−1 H-atom−1, (10.2 ± 0.4stat +1.2 −1.7sys) × 10−27 photons s−1 sr−1 H-atom−1, and (9.1 ± 0.3stat +1.5 −0.6sys) × 10−27 photons s−1 sr−1 H-atom−1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250 MeV to 10 GeV indicate a variation of the CR density by ∼20% in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, XCO = N(H2)/WCO, is found to be (0.96 ± 0.06stat +0.15 −0.12sys) × 1020 H2-molecule cm−2 (K km s−1)−1, (0.99 ± 0.08stat +0.18 −0.10sys) × 1020 H2-molecule cm−2 (K km s−1)−1, and (0.63 ± 0.02stat +0.09 −0.07sys) × 1020 H2-molecule cm−2 (K km s−1)−1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of XCO in the vicinity of the solar system. From the obtained values of XCO, the masses of molecular gas traced by WCO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be ∼5 × 103M , ∼103M , and ∼3.3 × 104M , respectively. A comparable amount of gas not traced well by standard Hi and CO surveys is found in the regions investigated.

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Title: FERMI LARGE AREA TELESCOPE STUDY OF COSMIC RAYS AND THE INTERSTELLAR MEDIUM IN NEARBY MOLECULAR CLOUDS
Creators - without role: Markus Ackermann - Deutsches Elektronen-Synchrotron DESY
Marco Ajello - Stanford University
A. Allafort - Kavli Institute for Particle Astrophysics and Cosmology
Luca Baldini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
Jean Ballet - Astrophysique, Instrumentation et Modélisation
Guido Barbiellini - University of Trieste
D. Bastieri - University of Padua
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
R. D. Blandford
E. D. Bloom
E. Bonamente - University of Perugia
A. W. Borgland
E. Bottacini - Kavli Institute for Particle Astrophysics and Cosmology
T. J. Brandt - Institut de Recherche en Astrophysique et Planétologie
J. Bregeon - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Brigida - Polytechnic University of Bari
Pascal Bruel - École Polytechnique
R. Buehler - Kavli Institute for Particle Astrophysics and Cosmology
G. Busetto - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
S. Buson - University of Padua
G. A. Caliandro
R. A. Cameron
P. A. Caraveo - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
J. M. Casandjian - Astrophysique Interprétation Modélisation
C. Cecchi - University of Perugia
E. Charles - Kavli Institute for Particle Astrophysics and Cosmology
A. Chekhtman - George Mason University
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 - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
J. Conrad - Stockholm University
F. d'Ammando
A. de Angelis - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
F. de Palma - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
C. D. Dermer
S. W. Digel
E. Do Couto E Silva
P. S. Drell
A. Drlica-Wagner - Kavli Institute for Particle Astrophysics and Cosmology
L. Falletti - Laboratoire Univers et Particules de Montpellier
C. Favuzzi - Polytechnic University of Bari
S. J. Fegan - Laboratoire Leprince-Ringuet
E. C. Ferrara
W. B. Focke
Y. Fukazawa - Hiroshima University
Y. Fukui - Nagoya University
S. Funk - Stanford University
P. Fusco - Polytechnic University of Bari
F. Gargano - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
D. Gasparrini - Agenzia Spaziale Italiana
S. Germani - University of Perugia
N. Giglietto - Polytechnic University of Bari
F. Giordano - Polytechnic University of Bari
M. Giroletti - Istituto di Radioastronomia di Bologna
T. Glanzman - Stanford University
G. Godfrey - Kavli Institute for Particle Astrophysics and Cosmology
I. A. Grenier - Astrophysique Interprétation Modélisation
M.-H. Grondin - Heidelberg University
J. E. Grove
S. Guiriec - University of Alabama in Huntsville
D. Hadasch - Institute of Space Sciences
Y. Hanabata - Hiroshima University
A. K. Harding
K. Hayashi - Hiroshima University
D. Horan - Laboratoire Leprince-Ringuet
X. Hou - Laboratoire de Physique des deux infinis Bordeaux
R. E. Hughes
R. Itoh - Hiroshima University
M. S. Jackson
G. J'Ohannesson
A. S. Johnson
T. Kamae - Kavli Institute for Particle Astrophysics and Cosmology
H. Katagiri - Ibaraki University
J. Kataoka - Waseda University
Jürgen Knödlseder - Institut de Recherche en Astrophysique et Planétologie
M. Kuss - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
J. Lande - Kavli Institute for Particle Astrophysics and Cosmology
S. Larsson - Stockholm University
H. Lee
M. Lemoine-Goumard - Laboratoire de Physique des deux infinis Bordeaux
F. Longo - University of Trieste
F. Loparco - Polytechnic University of Bari
M. N. Lovellette
P. Lubrano - University of Perugia
P. Martin - Max Planck Institute for Extraterrestrial Physics
M. N. Mazziotta
J. E. Mcenery
J. Mehault - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
P. F. Michelson
W. Mitthumsir
T. Mizuno - Hiroshima University
A. A. Moiseev
C. Monte - Polytechnic University of Bari
M. E. Monzani
A. Morselli - Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata
I. V. Moskalenko
S. Murgia - Kavli Institute for Particle Astrophysics and Cosmology
M. Naumann-Godo - CEA Paris-Saclay
R. Nemmen - Goddard Space Flight Center
S. Nishino - Hiroshima University
J. P. Norris
E. Nuss - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
M. Ohno - Institute of Space and Astronautical Science
T. Ohsugi - Hiroshima University
A. Okumura - Kavli Institute for Particle Astrophysics and Cosmology
N. Omode
E. Orlando - Kavli Institute for Particle Astrophysics and Cosmology
J. F. Ormes
M. Ozaki - Institute of Space and Astronautical Science
D. Paneque - Stanford University
J. H. Panetta
D. Parent - George Mason University
M. Pesce-Rollins - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Pierbattista - Astrophysique, Instrumentation et Modélisation
F. Piron - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
G. Pivato - University of Padua
T.A. Porter - Kavli Institute for Particle Astrophysics and Cosmology
S. Rain'O
R. Rando - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
M. Razzano - University of California, Santa Cruz
A. Reimer - Universität Innsbruck
O. Reimer - Universität Innsbruck
C. Romoli - University of Padua
M. Rot
T. Sada - Hiroshima University
H. F.-W. Sadrozinski
D.A. Sanchez - Max Planck Institute for Nuclear Physics
C. Sbarra - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
C. Sgr'O
E. J. Siskind
G. Spandre - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. Spinelli - Polytechnic University of Bari
A. W. Strong
D. J. Suson
H. Takahashi - Hiroshima University
T. Takahashi - Institute of Space and Astronautical Science
T. Tanaka - Kavli Institute for Particle Astrophysics and Cosmology
J. G. Thayer
J. B. Thayer
D. J. Thompson
L. Tibaldo - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
O. Tibolla - University of Würzburg
M. Tinivella - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
D. F. Torres
G. Tosti - University of Perugia
A. Tramacer
E. Troja - Goddard Space Flight Center
Y. Uchiyama - Kavli Institute for Particle Astrophysics and Cosmology
T. Uehara - Hiroshima University
T. L. Usher
J. Vandenbroucke - Kavli Institute for Particle Astrophysics and Cosmology
V. Vasileiou - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
G. Vianello - Consorzio Interuniversitario Fisica Spaziale
V. Vitale - University of Rome Tor Vergata
A. P. Waite
P. Wang - Kavli Institute for Particle Astrophysics and Cosmology
B. L. Winer
K. S. Wood
H. Yamamoto - Nagoya University
Z. Yang - AlbaNova
D. S. Zimmer
Publication Details: The Astrophysical Journal, Vol.755
Identifiers: 9937517509311
Academic Unit: Laboratoire Univers et Particules de Montpellier - LUPM
Language: English
Resource Type: Journal article
Local Fields: in2p3-00735197