{
  "bibcode": "2020GCN.27411....1T",
  "email": "eleonora@umd.edu",
  "body": "E. Troja (UMD/NASA/GSFC), L. Piro (INAF/IAPS), G. Ryan (UMD), H. van Eerten\n(Bath U.), B. Zhang (UNLV) ob behalf of a larger collaboration\n\nThe Chandra X-ray Observatory re-observed the field of GW170817 between\nMarch 9th and March 15th, 2020,and performed four short exposures\nobservations (ObsIDs: 21323, 23183, 23184, 23185)\nfor a total of 96 ks, as part of its on-going monitoring program. At the\nafterglow position, an X-ray source is detected with significance >4.5\nsigma\nat an average count rate of (8+/-0.4)e-05 cts/s in the 0.5-8.0 keV energy\nband. By using an absorbed power-law model with absorption column fixed at\nthe Galactic value of 7.5E20 cm^-2 and a photon index Gamma=1.585, as\nderived from our broadband analysis, we estimate an unabsorbed X-ray flux\nof (1.1 +/- 0.6)E-15 erg/cm2/s in the 0.3-10 keV energy band. The quoted\nerror is at the 68% confidence level.\nThis new measurement is higher than earlier predictions of a structured\njet, based on a full year of data (Troja E., et al., 2019, MNRAS, 489,\n1919),\nyet still consistent with this model within the uncertainties.\n\nAdditional components of emission, such as continued energy injection from\na long-lived neutron star (Piro L., et al., 2019, MNRAS, 483, 1912) or\nafterglow from the sub-relativistic ejecta (Kathirgamaraju A., Giannios D.,\nBeniamini P., 2019, MNRAS, 487, 3914), cannot be excluded at this time.\n\nFurther analysis is on-going.",
  "eventId": "GW170817",
  "submitter": "Eleonora Troja at NASA/GSFC/UMD  <eleonora@umd.edu>",
  "subject": "GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger",
  "editedBy": "courey.elliott@gmail.com",
  "editedOn": 1757443034523,
  "circularId": 27411,
  "createdOn": 1584554350000,
  "version": 2
}