Detection of the Small Magellanic Cloud in gamma-rays with Fermi/LAT

被引：78

作者：

Abdo, A. A. ^{[1
,2
]}

Ackermann, M. ^{[3
,4
]}

Ajello, M. ^{[3
,4
]}

Baldini, L. ^{[5
]}

Ballet, J. ^{[6
]}

Barbiellini, G. ^{[7
,8
]}

Bastieri, D. ^{[9
,10
]}

Bechtol, K. ^{[3
,4
]}

Bellazzini, R. ^{[5
]}

Berenji, B. ^{[3
,4
]}

Blandford, D. ^{[3
,4
]}

Bloom, E. D. ^{[3
,4
]}

Bonamente, E. ^{[11
,12
]}

Borgland, A. W. ^{[3
,4
]}

Bouvier, A. ^{[3
,4
]}

Brandt, T. J. ^{[13
,14
]}

Bregeon, J. ^{[5
]}

Brez, A. ^{[5
]}

Brigida, M. ^{[15
,16
,17
]}

Bruel, P. ^{[18
]}

Buehler, R. ^{[3
,4
]}

Buson, S. ^{[9
,10
]}

Caliandro, G. A. ^{[19
]}

Cameron, R. A. ^{[3
,4
]}

Caraveo, P. A. ^{[20
]}

Carrigan, S. ^{[10
]}

Casandjian, J. M. ^{[6
]}

Cecchi, C. ^{[11
,12
]}

Celik, Oe. ^{[21
,22
,23
,24
]}

Charles, E. ^{[3
,4
]}

Chekhtman, A. ^{[1
,25
]}

Cheung, C. C. ^{[1
,2
]}

Chiang, J. ^{[3
,4
]}

Ciprini, S. ^{[12
]}

Claus, R. ^{[3
,4
]}

Cohen-Tanugi, J. ^{[26
]}

Conrad, J. ^{[27
,28
]}

Dermer, C. D. ^{[1
]}

de Palma, F. ^{[15
,16
,17
]}

Digel, S. W. ^{[3
,4
]}

do Couto e Silva, E. ^{[3
,4
]}

Drell, P. S. ^{[3
,4
]}

Dubois, R. ^{[3
,4
]}

Dumora, D. ^{[29
,30
]}

Favuzzi, C. ^{[15
,16
,17
]}

Fegan, S. J. ^{[18
]}

Fukazawa, Y. ^{[31
]}

Funk, S. ^{[3
,4
]}

Fusco, P. ^{[15
,16
,17
]}

Gargano, F. ^{[17
]}

机构：

[1] USN, Div Space Sci, Res Lab, Washington, DC 20375 USA

[2] Natl Acad Sci, Natl Res Council Res Associate, Washington, DC 20001 USA

[3] Stanford Univ, Dept Phys, Kavli Inst Particle Astrophys & Cosmol, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA

[4] Stanford Univ, SLAC Natl Accelerator Lab, Stanford, CA 94305 USA

[5] Ist Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, Italy

[6] Univ Paris Diderot, CEA Saclay, CNRS, Serv Astrophys,Lab AIM,CEA IRFU, F-91191 Gif Sur Yvette, France

[7] Ist Nazl Fis Nucl, Sez Trieste, I-34127 Trieste, Italy

[8] Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy

[9] Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy

[10] Univ Padua, Dipartimento Fis G Galilei, I-35131 Padua, Italy

[11] Ist Nazl Fis Nucl, Sez Perugia, I-06123 Perugia, Italy

[12] Univ Perugia, Dipartimento Fis, I-06123 Perugia, Italy

[13] CNRS UPS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France

[14] Ohio State Univ, Dept Phys, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA

[15] Univ Bari, Dipartimento Fis M Merlin, I-70126 Bari, Italy

[16] Politecn Bari, Dipartimento Fis M Merlin, I-70126 Bari, Italy

[17] Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy

[18] Ecole Polytech, CNRS, IN2P3, Lab Leprince Ringuet, F-91128 Palaiseau, France

[19] Inst Ciencies Espai IEEC CSIC, Barcelona 08193, Spain

[20] Ist Astrofis Spaziale & Fis Cosm, INAF, I-20133 Milan, Italy

[21] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA

[22] CRESST, Greenbelt, MD 20771 USA

[23] Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA

[24] Univ Maryland Baltimore Cty, Ctr Space Sci & Technol, Baltimore, MD 21250 USA

[25] George Mason Univ, Fairfax, VA 22030 USA

[26] Univ Montpellier 2, CNRS, IN2P3, Lab Phys Theor & Astroparticules, Montpellier, France

[27] Stockholm Univ, Dept Phys, S-10691 Stockholm, Sweden

[28] Oskar Klein Ctr Cosmoparticle Phys, S-10691 Stockholm, Sweden

[29] Ctr Etud Nucl Bordeaux Gradignan, CNRS, IN2P3, UMR 5797, F-33175 Gradignan, France

[30] Univ Bordeaux, Ctr Etud Nucl Bordeaux Gradignan, UMR 5797, F-33175 Gradignan, France

[31] Hiroshima Univ, Dept Phys Sci, Hiroshima 7398526, Japan

[32] ASI, Sci Data Ctr, I-00044 Frascati, Roma, Italy

[33] INAF Inst Radioastron, I-40129 Bologna, Italy

[34] Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA

[35] ICREA, Barcelona, Spain

[36] Waseda Univ, Res Inst Sci & Engn, Shinjuku Ku, Tokyo 1698555, Japan

[37] Univ Washington, Dept Phys, Seattle, WA 98195 USA

[38] Max Planck Inst Extraterr Phys, D-85748 Garching, Germany

[39] Univ Maryland, Dept Phys, College Pk, MD 20742 USA

[40] Univ Maryland, Dept Astron, College Pk, MD 20742 USA

[41] Ist Nazl Fis Nucl, Sez Roma Tor Vergata, I-00133 Rome, Italy

[42] Univ Denver, Dept Phys & Astron, Denver, CO 80208 USA

[43] Hiroshima Univ, Hiroshima Astrophys Sci Ctr, Hiroshima 7398526, Japan

[44] JAXA, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan

[45] Leopold Franzens Univ Innsbruck, Inst Astro & Teilchenphys, A-6020 Innsbruck, Austria

[46] Leopold Franzens Univ Innsbruck, Inst Theoret Phys, A-6020 Innsbruck, Austria

[47] Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Dept Phys, Santa Cruz, CA 95064 USA

[48] Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA

[49] NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA

[50] NYCB Real Time Comp Inc, Lattingtown, NY 11560 USA

来源：

ASTRONOMY & ASTROPHYSICS | 2010年 / 523卷

关键词：

acceleration of particles; cosmic rays; Magellanic Clouds; gamma rays: general; ENERGY COSMIC-RAYS; ACTIVE GALACTIC NUCLEI; LARGE-AREA TELESCOPE; ALL-SKY SURVEY; X-RAY; INFRARED-EMISSION; STAR-FORMATION; DRIVEN DYNAMO; SOURCE LIST; GALAXY;

D O I：

10.1051/0004-6361/201014855

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Context. The flux of gamma rays with energies greater than 100 MeV is dominated by diffuse emission coming from cosmic-rays (CRs) illuminating the interstellar medium (ISM) of our Galaxy through the processes of Bremsstrahlung, pion production and decay, and inverse-Compton scattering. The study of this diffuse emission provides insight into the origin and transport of cosmic rays. Aims. We searched for gamma-ray emission from the Small Magellanic Cloud (SMC) in order to derive constraints on the cosmic-ray population and transport in an external system with properties different from the Milky Way. Methods. We analysed the first 17 months of continuous all-sky observations by the Large Area Telescope (LAT) of the Fermi mission to determine the spatial distribution, flux and spectrum of the gamma-ray emission from the SMC. We also used past radio synchrotron observations of the SMC to study the population of CR electrons specifically. Results. We obtained the first detection of the SMC in high-energy gamma rays, with an integrated >100 MeV flux of (3.7 +/- 0.7) x 10(-8) ph cm(-2) s(-1), with additional systematic uncertainty of <= 16%. The emission is steady and from an extended source similar to 3 degrees in size. It is not clearly correlated with the distribution of massive stars or neutral gas, nor with known pulsars or supernova remnants, but a certain correlation with supergiant shells is observed. Conclusions. The observed flux implies an upper limit on the average CR nuclei density in the SMC of similar to 15% of the value measured locally in the Milky Way. The population of high-energy pulsars of the SMC may account for a substantial fraction of the gamma-ray flux, which would make the inferred CR nuclei density even lower. The average density of CR electrons derived from radio synchrotron observations is consistent with the same reduction factor but the uncertainties are large. From our current knowledge of the SMC, such a low CR density does not seem to be due to a lower rate of CR injection and rather indicates a smaller CR confinement volume characteristic size.

引用

页数：14

共 65 条

[31] Unveiling extensive clouds of dark gas in the solar neighborhood
Grenier, IA
Casandjian, JM
Terrier, R
[J]. SCIENCE, 2005, 307 (5713) : 1292 - 1295
[32] Amplification of galactic magnetic fields by the cosmic-ray-driven dynamo
Hanasz, M
Kowal, G
Otmianowska-Mazur, K
Lesch, H
[J]. ASTROPHYSICAL JOURNAL, 2004, 605 (01) : L33 - L36
[33] Cosmic-ray-driven dynamo in galactic disks A parameter study
Hanasz, M.
Otmianowska-Mazur, K.
Kowal, G.
Lesch, H.
[J]. ASTRONOMY & ASTROPHYSICS, 2009, 498 (02) : 335 - 346
[34] The star formation history of the Small Magellanic Cloud
Harris, J
Zaritsky, D
[J]. ASTRONOMICAL JOURNAL, 2004, 127 (03) : 1531 - 1544
[35] HAYNES RF, 1991, ASTRON ASTROPHYS, V252, P475
[36] CRATES: An All-Sky Survey of flat-spectrum radio sources
Healey, Stephen E.
Romani, Roger W.
Taylor, Gregory B.
Sadler, Elaine M.
Ricci, Roberto
Murphy, Tara
Ulvestad, James S.
Winn, Joshua N.
[J]. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2007, 171 (01) : 61 - 71
[37] Forty eclipsing binaries in the Small Magellanic Cloud: fundamental parameters and Cloud distance
Hilditch, RW
Howarth, ID
Harries, TJ
[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2005, 357 (01) : 304 - 324
[38] Star formation in irregular galaxies: A review of several key questions
Hunter, DA
[J]. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 1997, 109 (739) : 937 - 950
[39] THE IMPLICATIONS OF A HIGH COSMIC-RAY IONIZATION RATE IN DIFFUSE INTERSTELLAR CLOUDS
Indriolo, Nick
Fields, Brian D.
McCall, Benjamin J.
[J]. ASTROPHYSICAL JOURNAL, 2009, 694 (01) : 257 - 267
[40] Parameterization of γ, e±, and neutrino spectra produced by p-p interaction in astronomical environments
Kamae, Tuneyoshi
Karlsson, Niklas
Mizuno, Tsunefumi
Abe, Toshinori
Koi, Tatsumi
[J]. ASTROPHYSICAL JOURNAL, 2006, 647 (01) : 692 - 708

← 1 2 3 4 5 6 7 →