X-Ray Observations of Magnetar SGR 0501+4516 from Outburst to Quiescence
arXiv:1801.00937 · doi:10.3847/1538-4357/aa9e90
Abstract
Magnetars are neutron stars having extreme magnetic field strengths. Study of their emission properties in quiescent state can help understand effects of a strong magnetic field on neutron stars. SGR 0501+4516 is a magnetar that was discovered in 2008 during an outburst, which has recently returned to quiescence. We report its spectral and timing properties measured with new and archival observations from the Chandra X-Ray Observatory, XMM-Newton, and Suzaku. We found that the quiescent spectrum is best fit by a power-law plus two blackbody model, with temperatures of kT_low~0.26 keV and kT_high~0.62 keV. We interpret these two blackbody components as emission from a hotspot and the entire surface. The hotspot radius shrunk from 1.4 km to 0.49 km since the outburst, and there was a significant correlation between its area and the X-ray luminosity, which agrees well with the prediction by the twisted magnetosphere model. We applied the two temperature spectral model to all magnetars in quiescence and found that it could be a common feature among the population. Moreover, the temperature of the cooler blackbody shows a general trend with the magnetar field strength, which supports the simple scenario of heating by magnetic field decay.
Accepted for publication by the ApJ; 11 pages, 8 figures, 5 tables
References in corpus (16)
- Untwisting magnetospheres of neutron stars
- Magnetar-like Emission from the Young Pulsar in Kes 75
- Resonant cyclotron scattering in magnetars' emission
- 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
- Evidence for Heating of Neutron Stars by Magnetic Field Decay
- The first XMM-Newton observations of the Soft Gamma-ray Repeater SGR 1900+14
- Radio Spectrum and Distance of the SNR HB9
- The 2008 May burst activation of SGR 1627-41
- From outburst to quiescence: the decay of the transient Anomalous X-ray Pulsar XTE J1810-197
- X-ray and Near-IR Variability of the Anomalous X-ray Pulsar 1E 1048.1-5937: From Quiescence Back to Activity
- Magnetar-like X-ray Bursts from a Rotation Powered Pulsar, PSR J1119-6127
- Very deep X-ray observations of the Anomalous X-ray Pulsar 4U 0142+614
- XMM-Newton observations of CXOU J010043.1-721134: the first deep look at the soft X-ray emission of a magnetar
- SGR 1806-20 about two years after the giant flare: Suzaku, XMM-Newton and INTEGRAL observations
- Swift and Chandra confirm the intensity-hardness correlation of the AXP 1RXS J170849.0-400910
- Intensity-hardness correlation and deep infrared observation of the anomalous X-ray pulsar 1RXS J170849-400910