AstroSat observation of the Be/X-ray binary Pulsar 3A 0726–260(4U 0728–25)

作者：Jayashree Roy,Prahlad C.Agrawal,Baibhav Singari,Ranjeev Misra

摘要：Results on timing and spectral properties of the Be/X-ray binary pulsar 3A 0726-260(4U 0728-25)are presented.The binary was observed on 2016 May 6-7 with the Large Area X-ray Proportional Counter(LAXPC)and Soft X-ray Telescope(SXT)instruments onboard the AstroSat satellite.During this observation,the source was in non-flaring persistent state at a flux level of~8.6±0.3×10^-11 erg cm^-2 s^-1in 0.4-20 keV.Strong X-ray pulsations with a period of 103.144±0.001 s are detected in 0.3-7 keV with the SXT and in 3-40 keV with the LAXPC.The pulse profile is energy dependent,and there is an indication that the pulse shape changes from a broad single pulse to a double pulse at higher energy.At energies above20 keV,we report the first time detection of pulsation period 103.145±0.001 s and the double peaked pulse profile from the source.The energy spectrum of the source is derived from the combined analysis of the SXT and LAXPC spectral data in 0.4-20 keV.The best spectral fit is obtained by a power law model with a photon index(1.7±0.03)with high energy spectral cut-off at 12.9±0.7 keV.A broad iron line at~6.3 keV is detected in the energy spectrum.We briefly discuss the implications of these results.

发文机构：UM-DAE Centre for Excellence in Basic Sciences Inter-University Center for Astronomy and Astrophysics School of Physical Sciences

关键词：Be/Xraybinarypulsar4U0728–25

分类号： O57[理学—粒子物理与原子核物理]