{
  "bibcode": "2009GCN..8900....1C",
  "body": "ICSP VLF observation of  SGR/AXP 1E1547.0-5408 bursts on 22nd January, 2009\n\nSandip K. Chakrabarti (S. N. Bose Centre and ICSP), Sushanta K. Mondal (ICSP),\nSudipta Sasmal (ICSP) and D. Bhowmick (ICSP)\n\nIn a previous GCN (#8881) we reported that we were able to identify signatures\nof unusual\nactivities in the ionosphere based on VLF data averaged over 10 points (5\nseconds). After\ncorrecting the time stamps and using non-averaged data we are now in a\nposition to claim that\nnumerous ionospheric activities (fast rise and slow decay light curves over\n10-20 seconds or more)\nhave been observed on 22nd January, many of which match the activities\nreported in previous\nGCNs from FERMI/INTEGRAL/SUZAKU/RHESSI and other teams (e.g., GCNs 8833, 8835,\n8837, 8838). Due to\nintrinsic problem of directional insensitivity and recombination time in lower\nionosphe we found two problems (a) Begining of new activity before the earlier\none decayed causing\ndisplay of 'non-ideal' shape change, (b) influence of other active sources\ncould be present.\n\nInteresting cases where many activities happened in close succession (as\nreported mainly\nby SUZAKU and HESSI) have been separated and they can be found in four PDF files\n(one2two.pdf, two2three.pdf, 426to533.pdf and eight2nine.pdf). Unlike one or\ntwo cases\nin our previous  circular #8881 (based on smoothed data) attenuation events\nwere not found\nwhen original data was used. These files are in\nhttp://www.bose.res.in/~chakraba/axpsgr2.html.\n\nIn order to understand the response of the ionosphere by X-ray/gamma-ray\nactivities better,\nwe urge other VLF observers to report if they obtained any such effects. They\nmust check\nif the object was over their sky during the active period.\n\n\nProf. Sandip K. Chakrabarti\nSenior Professor and Head, Astrophysics and Cosmology\nS.N. Bose National Centre for Basic Sciences\nJD Block, Salt Lake, Kolkata 700098 INDIA\nTel: 23355706\nand\nIn Charge, Academic Affairs\nIndian Centre for Space Physics\nChalantika 43, Garia Station Road,\nKolkata 700084 INDIA\nM: 9903120700\nTel: 24366003/24622153\n--\nOpen WebMail Project (http://openwebmail.org)",
  "circularId": 8900,
  "createdOn": 1234328517000,
  "email": "chakraba@bose.res.in",
  "subject": "Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408",
  "submitter": "Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>"
}