The magnetar candidate AX J1818.8-1559

Abstract

In October 2007 a hard X-ray burst was detected by the INTEGRAL satellite from a direction consistent with the position of AX J1818.8-1559, an X-ray source at low Galactic latitude discovered with the ASCA satellite in 1996-1999. The short duration (0.8 s) and soft spectrum (power law photon index of 3.0+/-0.2) of the burst in the 20-100 keV range are typical of Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars. We report on the results of an observation of AX J1818.8-1559 obtained with the Suzaku satellite in October 2011. The source spectrum, a power law with photon index 1.5, and flux 2x10^{-12} erg cm^-2 s^-1 (2-10 keV), do not show significant variations with respect to the values derived from archival data of various satellites (ROSAT, XMM-Newton, Chandra, Swift) obtained from 1993 to 2011. We discuss possible interpretations for AX J1818.8-1559 and, based on its association with the INTEGRAL burst, we propose it as a new member of the small class of magnetar candidates.

Accepted for publication in Astronomy and Astrophysics

References in corpus (11)

• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• The UKIDSS Galactic Plane Survey
• Transient pulsed radio emission from a magnetar
• 1E 1547.0-5408: a radio-emitting magnetar with a rotation period of 2 seconds
• A Swift gaze into the 2006 March 29th burst forest of SGR 1900+14
• The Compact X-ray Source 1E 1547.0-5408 and the Radio Shell G327.24-0.13: A New Proposed Association between a Candidate Magnetar and a Candidate Supernova Remnant
• Multi-wavelength Observations of the Radio Magnetar PSR J1622-4950 and Discovery of its Possibly Associated Supernova Remnant
• The 2008 May burst activation of SGR 1627-41
• The updated spectral catalogue of INTEGRAL Gamma-Ray Bursts
• AXPs/SGRs: Magnetars or Quark-stars?
• What do exotic equations of state have to offer?

Cited by in corpus (6)

• The McGill Magnetar Catalog
• The Sardinia Radio Telescope: From a Technological Project to a Radio Observatory
• Magnetar Broadband X-ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE
• A very young radio-loud magnetar
• Chasing the Identification of ASCA Galactic Objects (ChIcAGO) - An X-ray Survey of Unidentified Sources in the Galactic Plane I: Source Sample and Initial Results
• New candidates for magnetar counterparts from a deep search with the Hubble Space Telescope