Diagnostic of the spectral properties of Aquila X-1 by Insight-HXMT snapshots during the early propeller phase

Gungor C. , Ge M. Y. , Zhang S., Santangelo A., Zhang S. N. , Lu F. J. , ...More

JOURNAL OF HIGH ENERGY ASTROPHYSICS, vol.25, pp.10-16, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25
  • Publication Date: 2020
  • Doi Number: 10.1016/j.jheap.2019.12.001
  • Page Numbers: pp.10-16


We study the 2018 outburst of Aql X-1 via the monitor of all sky X-ray image (MAXI) data. We show that the outburst starting in February 2018 is a member of short-lowclass in the frame of outburst duration and the peak count rate although the outburst morphology is slightly different from the other fastrise-exponential-decay (FRED) type outbursts with a milder rising stage. We study the partial accretion in the weak propeller stage of Aql X-1 via the MAXI data of the 2018 outburst. We report on the spectral analysis of 3 observations of Aquila X-1 obtained by Insight - hard X-ray modulation telescope (Insight-HXMT) during the late decay stage of the 2018 outburst. We discuss that the data taken by Insight-HXMT is just after the transition to the weak propeller stage. Our analysis shows the necessity of a comptonization component to take into account the existence of an electron cloud resulting photons partly up-scattered. (C) 2019 Elsevier B.V. All rights reserved.