{
  "bibcode": "2015GCN.17508....1R",
  "body": "O.J Roberts (UCD) reports on behalf of the Fermi GBM Team:\n\n\"At 04:53:25.04 UT on the 28th of February 2015, the Fermi\nGamma-Ray Burst Monitor triggered (446792008/150228204)\non a burst from magnetar 4U 0142+61, which was also\nreported by Barthelmy et al. (GCN 17507). The GBM on-ground\nlocation is consistent with the known source position.\n\nThe triggered event consists of 4-5 bursts, each with a\nduration of about 0.1s, that occur over a duration of about\n20s. The two brightest bursts occur at T0-0.06s and T0+10.0s.\nThe burst at T0+10s is well-fit with a power law function with\nan exponential high-energy cutoff. The power law index is\n-0.38 +/- 0.33 and the cutoff energy, parameterised as Epeak,\nis 74 +/- 8 keV. The fluence during T0+10.048s to T0+10.304s\nis (2.703 +/- 0.384)E-07  erg/cm^2. The corresponding peak\nflux integrated over 16ms (10-1000 keV) is\n(11 +/- 1)E-06  ph/s/cm^2. The second burst at T0-0.064s is\nbest fit by a power law function with an exponential high-energy\ncutoff. The power law index is -0.31 +/- 0.39 and the cutoff\nenergy, parameterised as Epeak, is 55 +/- 5 keV. The fluence\nduring T0-0.064s to T0+0.064s is (2.716 +/- 0.241)E-07 erg/cm^2.\nThe corresponding peak flux integrated over 16ms (10-1000 keV)\nis (18 +/- 1)E-06  ph/s/cm^2.\n\nThis burst was followed by another trigger at 05:06:55.63 UT\n(trigger 446792818/150228213) on the 28th of February 2015,\nand is also consistent with being from magnetar 4U 0142+61.\nThis trigger consists of a bright, short (t<~0.3s) single peak.\n\nThe analysis results presented above are preliminary.\n\nThese bursts are bright enough that some are being classified by\nthe flight software as GRBs. We will correct this classification\nin the online catalogue at the Fermi Science Support Center:\n\nhttp://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html\n\nbut will not issue individual circulars to correct the classification\nfor triggers from this source.\"",
  "circularId": 17508,
  "createdOn": 1425142652000,
  "email": "oliver.roberts@ucd.ie",
  "subject": "Fermi GBM Observations of Magnetar 4U 0142+61",
  "submitter": "Oliver Roberts at UCD/Fermi  <oliver.roberts@ucd.ie>"
}