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Hard X-ray Variations in the Crab Nebula
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Author and Affiliation:
Wilson-Hodge, Colleen A.(NASA Marshall Space Flight Center, Huntsville, AL, United States);
Cherry, M. L.(Louisiana State Univ., LA, United States);
Case, G. L.(Louisiana State Univ., LA, United States);
Baumgarter, W. H.(NASA Goddard Space Flight Center, Greenbelt, MD, United States);
Beklen, E.(METU/SDU, unknown);
Bhat, P. N.(Alabama Univ., Huntsville, AL, United States);
Briggs, M. S.(Alabama Univ., Huntsville, AL, United States);
Camero-Arranz, A.(Universities Space Research Association, Huntsville, AL, United States);
Chaplin, V.(Alabama Univ., Huntsville, AL, United States);
Connaughton, V.(Alabama Univ., Huntsville, AL, United States);
Finger, M. H.(Universities Space Research Association, Huntsville, AL, United States);
Gehrels, N.(NASA Goddard Space Flight Center, Greenbelt, MD, United States);
Greiner, J.(Max-Planck-Inst. fuer Extraterrestrische Physik, Garching, Germany);
Jahoda, K.(NASA Goddard Space Flight Center, Greenbelt, MD, United States);
Jenke, P.(NASA Marshall Space Flight Center, Huntsville, AL, United States);
Kippen, R. M.(Los Alamos National Lab., NM, United States);
Kouveliotou, C.(NASA Marshall Space Flight Center, Huntsville, AL, United States);
Krimm, H. A.(Universities Space Research Association, Greenbelt, MD, United States);
Kuulkers, E.(European Space Astronomy Center (ESAC), unknown);
Lund, N.(Danish National Space Center, Denmark);
Meegan, C. A.(Universities Space Research Association, United States);
Natalucci, L.(Istituto di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF), Rome, Italy);
Paciesas, W. S.(Universities Space Research Association, United States);
Preece, R.(Alabama Univ., Huntsville, AL, United States);
Rodi, J. C.(Louisiana State Univ., LA, United States)
Abstract: In the first two years of science operations of the Fermi Gamma-ray Burst Monitor (GBM), August 2008 to August 2010, a approx.7% (70 mcrab) decline was discovered in the overall Crab Nebula flux in the 15 - 50 keV band, measured with the Earth occultation technique. This decline was independently confirmed with four other instruments: the RXTE/PCA, Swift/BAT, INTEGRAL/IBIS, and INTEGRAL/SPI. The pulsed flux measured with RXTE/PCA from 1999-2010 was consistent with the pulsar spin-down, indicating that the observed changes were nebular. From 2001 to 2010, the Crab nebula flux measured with RXTE/PCA was particularly variable, changing by up to approx.3.5% per year in the 15-50 keV band. These variations were confirmed with INTEGRAL/SPI starting in 2003, Swift/BAT starting in 2005, and Fermi GBM starting in 2008. Before 2001 and since 2010, the Crab nebula flux has appeared more stable, varying by less than 2% per year. I will present updated light curves in multiple energy bands for the Crab nebula, including recent data from Fermi GBM, Swift/BAT, and MAXI, and a 16-year long light curve from RXTE/PCA.
Publication Date: Oct 28, 2012
Document ID:
20130001680
(Acquired Jan 15, 2013)
Subject Category: ASTROPHYSICS
Report/Patent Number: M12-2069
Document Type: Conference Paper
Meeting Information: 4th International Fermi Symposium; 28 Oct. - 2 Nov. 2012; Monterey, CA; United States
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL, United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution as joint owner in the copyright
NASA Terms: CRAB NEBULA; PULSARS; LIGHT CURVE; ENERGY BANDS; X RAYS; GAMMA RAY BURSTS; OCCULTATION; X RAY TIMING EXPLORER
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