2018/01/03 by Y. -L. Mong, Y.-L. Mong, C. -Y. Ng +1
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black-body radiation #Gamma-ray bursts and supernovae #Magnetar #Magnetic field #Magnetosphere #Neutron star #Pulsar #Pulsars and Gravitational Waves Research #Spectral line #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/aa9e90
Accepted for publication by the ApJ; 11 pages, 8 figures, 5 tables
arxiv created 2018/01/03 · openalex publication_date 2018/01/10 · openalex created_date 2018/01/12 · arxiv updated 2018/01/24 · openalex updated_date 2026/08/06
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.