{
  "bibcode": "2001GCN..1056....1W",
  "body": "P. Woods (USRA/NSSTC), C. Kouveliotou (NASA/MSFC), and E. Gogus\n(UAH/NSSTC) report on behalf of a larger collaboration.\n\nToO observations of SGR 1900+14 with the Rossi XTE were initiated on\nApril 19, 2001 and have continued through April 28.  Thus far, more\nthan 60 bursts have been detected in ~110 ks of exposure time. \nCoincidentally, a short (~10 ks) observation of SGR 1900+14 was\nperformed on April 14 (4 days prior to the flare) as part of our\nongoing monitoring campaign.  We find no burst activity within this\nobservation.  For the latest observation on April 28, 4 bursts were\nrecorded in one RXTE orbit, thus the source remains burst active.\n\nSelecting a 6 day subset of these observations for which we have\nspacecraft ephemeris information, we have phase connected the data and\nmeasured both a period and period derivative.  We chose our epoch (MJD\n52021.3 TDB) to coincide with the first Chandra observation.  We\nmeasure a barycentric period of 5.1728219(14) s where the number given\nin the parentheses marks the 1 sigma error in the least significant\ndigits.  The period derivative is found to be +1.58(22) X 10E-10 s/s. \nThe ephemeris we find agrees well with the measured periods reported\nfor both the Chandra (GCN #1049) and BeppoSAX (GCN #1055)\nobservations.  Furthermore, the magnitude of the spindown found here\nis well within the range of historical spindown rates measured for\nthis SGR.\n\nThis message may be cited.",
  "circularId": 1056,
  "createdOn": 988650865000,
  "email": "peter.woods@msfc.nasa.gov",
  "subject": "SGR 1900+14 : RXTE observations",
  "submitter": "Peter Woods at UAH/MSFC  <peter.woods@msfc.nasa.gov>"
}