TY - JOUR
T1 - The X-Ray Modulation of PSR J2032+4127/MT91 213 during the Periastron Passage in 2017
AU - Li, K. L.
AU - Takata, J.
AU - Ng, C. W.
AU - Kong, A. K.H.
AU - Tam, P. H.T.
AU - Hui, C. Y.
AU - Cheng, K. S.
N1 - Funding Information:
Support for this work was partially provided by the National Aeronautics and Space Administration through Chandra Award Number GO7-18036X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. J.T. is supported by NSFC grants of Chinese Government under 11573010 and U1631103. P.H.T. is supported by the NSFC grant 11633007. Both are supported by NSFC grant 11661161010. A.K.H.K. is supported by the Ministry of Science and Technology of the Republic of China (Taiwan) through grants 105-2119-M-007-028-MY3 and 105-2112-M-007-033-MY2. C.Y.H. is supported by the National Research Foundation of Korea through grant 2016R1A5A1013277. K.S.C. is supported by GRF grant under 17302315. We acknowledge the use of public data from the Swift data archive. We also acknowledge the use of data and software facilities from the FSSC, managed by the HEASARC at the Goddard Space Flight Center. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Facilities: Swift, Fermi, VLA.
PY - 2018/4/20
Y1 - 2018/4/20
N2 - We present the Neil Gehrels Swift Observatory (Swift), Fermi Large Area Telescope (Fermi-LAT), and Karl G. Jansky Very Large Array (VLA) observations of the γ-ray binary PSR J2032+4127/MT91 213, of which the periastron passage recently occurred in 2017 November. In the Swift X-ray light curve, the flux was steadily increasing before 2017 mid-October, however, a sharp X-ray dip on a weekly timescale is seen during the periastron passage, followed by a post-periastron X-ray flare lasting for ∼20 days. We suggest that the X-ray dip is caused by (i) an increase of the magnetization parameter at the shock, and (ii) the suppression due to the Doppler boosting effect. The 20-day post-periastron flare could be a consequence of the Be stellar disk passage by the pulsar. An orbital GeV modulation is also expected in our model; however, no significant variability is seen in the Fermi-LAT light curve. We suspect that the GeV emission from the interaction between the binary's members is hidden behind the bright magnetospheric emission of the pulsar. The pulsar gating technique would be useful to remove the magnetospheric emission and recover the predicted GeV modulation, if an accurate radio timing solution over the periastron passage is provided in the future.
AB - We present the Neil Gehrels Swift Observatory (Swift), Fermi Large Area Telescope (Fermi-LAT), and Karl G. Jansky Very Large Array (VLA) observations of the γ-ray binary PSR J2032+4127/MT91 213, of which the periastron passage recently occurred in 2017 November. In the Swift X-ray light curve, the flux was steadily increasing before 2017 mid-October, however, a sharp X-ray dip on a weekly timescale is seen during the periastron passage, followed by a post-periastron X-ray flare lasting for ∼20 days. We suggest that the X-ray dip is caused by (i) an increase of the magnetization parameter at the shock, and (ii) the suppression due to the Doppler boosting effect. The 20-day post-periastron flare could be a consequence of the Be stellar disk passage by the pulsar. An orbital GeV modulation is also expected in our model; however, no significant variability is seen in the Fermi-LAT light curve. We suspect that the GeV emission from the interaction between the binary's members is hidden behind the bright magnetospheric emission of the pulsar. The pulsar gating technique would be useful to remove the magnetospheric emission and recover the predicted GeV modulation, if an accurate radio timing solution over the periastron passage is provided in the future.
UR - http://www.scopus.com/inward/record.url?scp=85046486420&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85046486420&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aab848
DO - 10.3847/1538-4357/aab848
M3 - Article
AN - SCOPUS:85046486420
VL - 857
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 123
ER -