J/ApJ/799/86 Isotropic diffuse gamma-ray emission 0.1-820GeV (Ackermann+, 2015)
The spectrum of isotropic diffuse gamma-ray emission between 100MeV and 820GeV.
Ackermann M., Ajello M., Albert A., Atwood W.B., Baldini L., Ballet J.,
Barbiellini G., Bastieri D., Bechtol K., Bellazzini R., Bissaldi E.,
Blandford R.D., Bloom E.D., Bottacini E., Brandt T.J., Bregeon J.,
Bruel P., Buehler R., Buson S., Caliandro G.A., Cameron R.A., Caragiulo M.,
Caraveo P.A., Cavazzuti E., Cecchi C., Charles E., Chekhtman A., Chiang J.,
Chiaro G., Ciprini S., Claus R., Cohen-Tanugi J., Conrad J., Cuoco A.,
Cutini S., D'Ammando F., de Angelis A., de Palma F., Dermer C.D.,
Digel S.W., do Couto e Silva E., Drell P.S., Favuzzi C., Ferrara E.C.,
Focke W.B., Franckowiak A., Fukazawa Y., Funk S., Fusco P., Gargano F.,
Gasparrini D., Germani S., Giglietto N., Giommi P., Giordano F.,
Giroletti M., Godfrey G., Gomez-Vargas G.A., Grenier I.A., Guiriec S.,
Gustafsson M., Hadasch D., Hayashi K., Hays E., Hewitt J.W., Ippoliti P.,
Jogler T., Johannesson G., Johnson A.S., Johnson W.N., Kamae T.,
Kataoka J., Knodlseder J., Kuss M., Larsson S., Latronico L., Li J., Li L.,
Longo F., Loparco F., Lott B., Lovellette M.N., Lubrano P., Madejski G.M.,
Manfreda A., Massaro F., Mayer M., Mazziotta M.N., McEnery J.E.,
Michelson P.F., Mitthumsiri W., Mizuno T., Moiseev A.A., Monzani M.E.,
Morselli A., Moskalenko I.V., Murgia S., Nemmen R., Nuss E., Ohsugi T.,
Omodei N., Orlando E., Ormes J.F., Paneque D., Panetta J.H., Perkins J.S.,
Pesce-Rollins M., Piron F., Pivato G., Porter T.A., Raino S., Rando R.,
Razzano M., Razzaque S., Reimer A., Reimer O., Reposeur T., Ritz S.,
Romani R.W., Sanchez-Conde M., Schaal M., Schulz A., Sgro C., Siskind E.J.,
Spandre G., Spinelli P., Strong A.W., Suson D.J., Takahashi H.,
Thayer J.G., Thayer J.B., Tibaldo L., Tinivella M., Torres D.F., Tosti G.,
Troja E., Uchiyama Y., Vianello G., Werner M., Winer B.L., Wood K.S.,
Wood M., Zaharijas G., Zimmer S.
<Astrophys. J., 799, 86 (2015)>
=2015ApJ...799...86A 2015ApJ...799...86A
ADC_Keywords: Gamma rays
Keywords: diffuse radiation; gamma rays: diffuse background
Abstract:
The γ-ray sky can be decomposed into individually detected
sources, diffuse emission attributed to the interactions of Galactic
cosmic rays with gas and radiation fields, and a residual all-sky
emission component commonly called the isotropic diffuse γ-ray
background (IGRB). The IGRB comprises all extragalactic emissions too
faint or too diffuse to be resolved in a given survey, as well as any
residual Galactic foregrounds that are approximately isotropic. The
first IGRB measurement with the Large Area Telescope (LAT) on board
the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of
sky-survey data and considered an energy range between 200MeV and
100GeV. Improvements in event selection and characterization of
cosmic-ray backgrounds, better understanding of the diffuse Galactic
emission (DGE), and a longer data accumulation of 50 months allow for
a refinement and extension of the IGRB measurement with the LAT, now
covering the energy range from 100MeV to 820GeV. The IGRB spectrum
shows a significant high-energy cutoff feature and can be well
described over nearly four decades in energy by a power law with
exponential cutoff having a spectral index of 2.32±0.02 and a break
energy of (279±52)GeV using our baseline DGE model. The total
intensity attributed to the IGRB is (7.2±0.6)x10-6/cm2/s/sr above
100MeV, with an additional +15%/-30% systematic uncertainty due to the
Galactic diffuse foregrounds.
Description:
Fifty months of Fermi/LAT data recorded between 2008 August 5 and 2012
October 6 are used for this analysis, corresponding to a total
observation time of 1239 days.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 149 78 Isotropic diffuse γ-ray background (IGRB) and
total extragalactic γ-ray background (EGB)
intensities
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See also:
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
J/ApJS/209/34 : The first Fermi-LAT >10GeV catalog (1FHL) (Ackermann+, 2013)
J/ApJS/208/17 : 2nd Fermi LAT cat. of gamma-ray pulsars (2PC) (Abdo+, 2013)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/A+A/534/A54 : GALPROP programme (Strong+, 2011)
J/ApJS/171/61 : All-Sky Survey of Flat-Spectrum Radio Sources (Healey+, 2007)
J/MNRAS/372/777 : Parkes Multibeam Pulsar Survey. VI. (Lorimer+, 2006)
http://fermi.gsfc.nasa.gov/ssc/ : Fermi Science Support Center home page
http://www.hawc-observatory.org/ : High-Altitude Water Cherenkov Observatory
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1 A1 --- Model [A-C] Model (1)
3- 10 F8.1 MeV Emin [100/579262] Lower energy range of band
12- 19 F8.1 MeV Emax [141/819200] Upper energy range of band
21- 29 E9.3 ph/cm2/s/sr fIGRB Integrated IGRB flux in band
31- 39 E9.3 ph/cm2/s/sr E_fIGRB Upper uncertainty in fIGRB (2)
41- 49 E9.3 ph/cm2/s/sr e_fIGRB Lower uncertainty in fIGRB (2)
51- 59 E9.3 ph/cm2/s/sr EfIGRB Upper uncertainty in fIGRB from
foreground modeling
61- 69 E9.3 ph/cm2/s/sr efIGRB Lower uncertainty in fIGRB from
foreground modeling
71- 79 E9.3 ph/cm2/s/sr fEGB Integrated total EGB in band (3)
81- 89 E9.3 ph/cm2/s/sr E_fEGB Upper uncertainty in fEGB (2)
91- 99 E9.3 ph/cm2/s/sr e_fEGB Lower uncertainty in fEGB (2)
101-109 E9.3 ph/cm2/s/sr EfEGB Upper uncertainty in fEGB from
foreground modeling
111-119 E9.3 ph/cm2/s/sr efEGB Lower uncertainty in fEGB from
foreground modeling
121-129 E9.3 ph/cm2/s/sr fsrc Integrated flux of sources in band (4)
131-139 E9.3 ph/cm2/s/sr E_fsrc Upper uncertainty in fsrc
141-149 E9.3 ph/cm2/s/sr e_fsrc Lower uncertainty in fsrc
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Note (1): Comparison of benchmark Galactic foreground models as follows:
A = Sources of CR nuclei and electrons trace pulsar distribution;
constant extragalactic cosmic ray (CR) diffusion coefficient and
reacceleration strength through Galaxy
B = Additional electron-only source population near Galactic center,
these electrons are responsible for majority of IC emission;
local source of soft CR electrons needed to explain CR electron spectrum
at Earth below 20GV
C = Sources of CR nuclei and electrons more centrally peaked than pulsar
distribution; cosmic ray (CR diffusion) coefficient and reacceleration
strength vary with galactocentric radius and height
Note (2): Statistical + instrument related systematics.
Note (3): IGRB + resolved sources.
Note (4): Sources resolved into individual sources for latitudes |b|>20°
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Jun-2015