The First Results of Monitoring Galactic Magnetar Activities with MAXI/GSC
Abstract
Magnetars are strongly magnetized neutron stars with surface magnetic fields up to 1015 G. In the galactic plane, 5 soft gamma repeaters (SGRs) and 8 anomalous X-ray pulsars (AXPs) are known as X-ray counterpart of the magnetars based on observational and theoretical studies. They exhibit thermal soft X-ray emission below ∼10 keV with a few mCrab fluxes. Interest-ingly, a hard power law component was found above ∼10 keV with a very hard index of -1 using INTEGRAL and Suzaku data. Some of the SGRs and AXPs presented a flux increasing by a factor of a few. During the high flux phases, some SGRs and AXPs exhibited high burst activities (e.g., Enoto et al. 2009) and/or enhanced quiescent emission with unusual spectral properties (e.g., Kaneko et al. 2010). In order to investigate radiation mechanisms, observa-tions of the high flux phases are important as well as those of the low flux phases. Therefore continuous monitoring of the SGRs and the AXPs are crucial to know their activities. Thanks to a wide field of view and a good sensitivity of the MAXI/GSC, it is suitable for the continuous monitoring of the SGRs and the AXPs. The MAXI/GSC has a better sensi-tivity than RXTE by a factor of a few in an energy range of 2-30 keV, and therefore detects ∼4 mCrab sources using accumulated data for ∼4 weeks. Among the 5 SGRs and 8 AXPs, AXP 4U 0142+614 and AXP 1E 1048.1-5937 are detected at least. In this paper, we will re-port the first results of monitoring the galactic SGRs and AXPs such as long-term light curves with the MAXI/GSC.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.2765N