MAGNETAR TWISTS: FERMI/GAMMA-RAY BURST MONITOR DETECTION OF SGR J1550-5418

Journal Article · Sat Feb 20 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/710/2/1335· OSTI ID:21394212

Kaneko, Yuki; Goegues, Ersin ^[1]; Kouveliotou, Chryssa; Van der Horst, Alexander J; Wilson-Hodge, Colleen A ^[2]; Granot, Jonathan ^[3]; Ramirez-Ruiz, Enrico ^[4]; Watts, Anna L; Van der Klis, Michiels ^[5]; Finger, Mark H ^[6]; Gehrels, Neil ^[7]; Pe'er, Asaf ^[8]; Von Kienlin, Andreas ^[9]; Wachter, Stefanie ^[10]

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1. SabanciUniversity, Orhanli-Tuzla, Istanbul 34956 (Turkey)
2. Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States)
3. Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)
4. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
5. Astronomical Institute Anton Pannekoek, University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands)
6. Universities Space Research Associations, NSSTC, Huntsville, AL 35805 (United States)
7. NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
8. Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)
9. Max-Planck Institut fuer extraterrestrische Physik, 85748 Garching (Germany)
10. Spitzer Science Center/California Institute of Technology, Pasadena, CA 91125 (United States)

SGR J1550-5418 (previously known as AXP 1E 1547.0-5408 or PSR J1550-5418) went into three active bursting episodes in 2008 October and in 2009 January and March, emitting hundreds of typical soft gamma repeater bursts in soft gamma rays. The second episode was especially intense, and our untriggered burst search on Fermi/Gamma-ray Burst Monitor (GBM) data (8-1000 keV) revealed {approx}450 bursts emitted over 24 hr during the peak of this activity. Using the GBM data, we identified a {approx}150 s long enhanced persistent emission during 2009 January 22 that exhibited intriguing timing and spectral properties: (1) clear pulsations up to {approx}110 keV at the spin period of the neutron star (P {approx} 2.07 s, the fastest of all magnetars); (2) an additional (to a power-law) blackbody component required for the enhanced emission spectra with kT {approx} 17 keV; and (3) pulsed fraction that is strongly energy dependent and highest in the 50-74 keV energy band. A total isotropic-equivalent energy emitted during this enhanced emission is estimated to be 2.9 x 10{sup 40}(D/5 kpc){sup 2} erg. The estimated area of the blackbody emitting region of {approx}0.046(D/5 kpc){sup 2} km{sup 2} (roughly a few x10{sup -5} of the neutron star area) is the smallest 'hot spot' ever measured for a magnetar and most likely corresponds to the size of magnetically confined plasma near the neutron star surface.

• OSTI ID: 21394212
• Journal Information: Astrophysical Journal, Vol. 710, Issue 2; Other Information: DOI: 10.1088/0004-637X/710/2/1335; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMIC GAMMA BURSTS
EMISSION
EMISSION SPECTRA
ENERGY DEPENDENCE
GAMMA RADIATION
KEV RANGE
NEUTRON STARS
NEUTRONS
PULSARS
PULSATIONS
X RADIATION
BARYONS
COSMIC RADIATION
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HADRONS
IONIZING RADIATIONS
NUCLEONS
PRIMARY COSMIC RADIATION
RADIATIONS
SPECTRA
STARS