NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
When a Standard Candle Flickers: Crab Nebula Variations in Hard X-raysRXTE played a crucial role in our surprising discovery that the Crab Nebula is variable in hard X-rays. In the first two years of science operations of the Fermi Gamma-ray Burst Monitor (GBM), August 2008-2010, 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 in the ~15-50 keV band 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 and Swift/BAT starting in 2005. Before 2001 and since 2010, the Crab nebula 15-50 keV flux measured with RXTE/PCA appeared more stable, varying by less than 2% per year. In this talk I will present Crab light curves including RXTE data for the entire 16-year mission in multiple energy bands.
Document ID
20120014194
Acquisition Source
Marshall Space Flight Center
Document Type
Abstract
Authors
Wilson-Hodge, Collen A. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Cherry, M. L. (Louisiana State Univ. Baton Rouge, LA, United States)
Case, G. L. (Louisiana State Univ. Baton Rouge, LA, United States)
Baumgartner, W. H. (Maryland Univ. College Park, MD, United States)
Beklen, E.
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.
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. Albuquerque, NM, United States)
Kouveliotou, C. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Krimm, H. A. (Universities Space Research Association Huntsville, AL, United States)
Kuulkers, E. (European Space Agency. ESA Tracking Station Madrid, Spain)
Lund, N. (Danish National Space Center Denmark)
Meegan, C. A. (Universities Space Research Association Huntsville, AL, United States)
Natalucci, L. (Istituto di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF) Rome, Italy)
Paciesas, W. S. (Universities Space Research Association Huntsville, AL, United States)
Preece, R. (Alabama Univ. Huntsville, AL, United States)
Rodi, J. C. (Louisiana State Univ. Baton Rouge, LA, United States)
Date Acquired
August 26, 2013
Publication Date
March 29, 2012
Subject Category
Astrophysics
Report/Patent Number
M12-1577
Meeting Information
Meeting: 16 Years of Discovery with RXTE: A Celebration of the Mission
Location: Greenbelt, MD
Country: United States
Start Date: March 29, 2012
End Date: March 30, 2012
Sponsors: NASA Goddard Space Flight Center
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available