Gamma-ray Burst 070517

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 17 May 07 11:21:43 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     279494,   Seg_Num: 0
  GRB_RA:          277.579d {+18h 30m 19s} (J2000),
                   277.751d {+18h 31m 00s} (current),
                   276.411d {+18h 25m 39s} (1950)
  GRB_DEC:         -62.333d {-62d 19' 56"} (J2000),
                   -62.327d {-62d 19' 37"} (current),
                   -62.367d {-62d 21' 58"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       15607 [cnts]    Image_Peak=370 [image_cnts]
  TRIGGER_DUR:     3.072 [sec] 
  TRIGGER_INDEX:   474     E_range: 25-100 keV
  BKG_INTEN:       147063 [cnts]
  BKG_TIME:        40814.03 SOD {11:20:14.03} UT
  BKG_DUR:         32 [sec]
  GRB_DATE:        14237 TJD;   137 DOY;   07/05/17
  GRB_TIME:        40858.39 SOD {11:20:58.39} UT
  GRB_PHI:         -100.53 [deg]
  GRB_THETA:        22.03 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     11.26 [sigma]
  IMAGE_SIGNIF:    8.00 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +3  +2  +2  +0  +0 +60  +1 
  SUN_POSTN:        53.87d {+03h 35m 30s}  +19.30d {+19d 17' 56"}
  SUN_DIST:        127.49 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
  MOON_POSTN:       62.72d {+04h 10m 52s}  +26.11d {+26d 06' 48"}
  MOON_DIST:       136.99 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      332.72,-21.46 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      274.52,-39.01 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 196.43,-10.42 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 17 May 07 11:22:49 UT
  NOTICE_TYPE:     Swift-XRT Nack-Position
  TRIGGER_NUM:     279494,   Seg_Num: 0
  POINT_RA:        277.589d {+18h 30m 21s} (J2000)
  POINT_DEC:       -62.324d {-62d 19' 24"} (J2000)
  IMG_START_DATE:  14237 TJD;   137 DOY;   07/05/17
  IMG_START_TIME:  40963.16 SOD {11:22:43.16} UT,   104.8 [sec] since BAT Trigger Time
  COUNTS:          27    Min_needed= 20
  STD_DEV:         5.40   Max_StdDev_for_Good=28.44 [arcsec]
  PH2_ITER:        1    Max_iter_allowed= 4
  ERROR_CODE:      3
  COMMENTS:        SWIFT-XRT Nack Position.
  COMMENTS:        Standard deviation too large.
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 17 May 07 11:24:34 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     279494,   Seg_Num: 0
  GRB_RA:          277.579d {+18h 30m 19s} (J2000),
                   277.751d {+18h 31m 00s} (current),
                   276.411d {+18h 25m 39s} (1950)
  GRB_DEC:         -62.333d {-62d 19' 56"} (J2000),
                   -62.327d {-62d 19' 37"} (current),
                   -62.367d {-62d 21' 58"} (1950)
  GRB_DATE:        14237 TJD;   137 DOY;   07/05/17
  GRB_TIME:        40858.39 SOD {11:20:58.39} UT
  TRIGGER_INDEX:   474
  GRB_PHI:         -100.53 [deg]
  GRB_THETA:        22.03 [deg]
  DELTA_TIME:      44.00 [sec]
  TRIGGER_DUR:     3.072 [sec]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     11.26 [sigma]
  IMAGE_SIGNIF:    8.00 [sigma]
  LC_URL:          sw00279494000msb.lc
  SUN_POSTN:        53.88d {+03h 35m 30s}  +19.30d {+19d 17' 57"}
  SUN_DIST:        127.49 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
  MOON_POSTN:       62.75d {+04h 10m 60s}  +26.12d {+26d 07' 09"}
  MOON_DIST:       137.01 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      332.72,-21.46 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      274.52,-39.01 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Lightcurve.
  COMMENTS:
  COMMENTS:        The next comments were copied from the BAT_POS Notice:
  COMMENTS:        This is a rate trigger.
  COMMENTS:        A point_source was found.
  COMMENTS:        This does not match any source in the on-board catalog.
  COMMENTS:        This does not match any source in the ground catalog.
  COMMENTS:        This is a GRB.
  COMMENTS:        This trigger occurred at longitude,latitude = 196.43,-10.42 [deg].
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 17 May 07 12:22:03 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     279494,   Seg_Num: 0
  GRB_RA:          277.6207d {+18h 30m 28.9s} (J2000),
                   277.7926d {+18h 31m 10.2s} (current),
                   276.4536d {+18h 25m 48.8s} (1950)
  GRB_DEC:         -62.2976d {-62d 17' 51.3"} (J2000),
                   -62.2921d {-62d 17' 31.5"} (current),
                   -62.3317d {-62d 19' 54.1"} (1950)
  GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       6.72e-11 [erg/cm2/sec]
  GRB_SIGNIF:      9.80 [sigma]
  IMG_START_DATE:  14237 TJD;   137 DOY;   07/05/17
  IMG_START_TIME:  40963.16 SOD {11:22:43.16} UT,   104.8 [sec] since BAT Trigger Time
  TAM[0-3]:        327.61 237.19 261.35 242.66
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:        53.92d {+03h 35m 40s}  +19.31d {+19d 18' 30"}
  SUN_DIST:        127.52 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
  MOON_POSTN:       63.39d {+04h 13m 35s}  +26.23d {+26d 13' 56"}
  MOON_DIST:       137.35 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      332.76,-21.47 [deg] galactic lon,lat of the burst
  ECL_COORDS:      274.55,-38.98 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.
  COMMENTS:        This Notice was ground-generated -- not flight-generated.
  COMMENTS:        TAM values are not valid.
  

• GCN Circular #6411
  S. D. Vergani (DIAS-DCU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), M. M. Chester (PSU), G. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), W. B. Landsman (NASA/GSFC), V. Mangano (INAF-IASFPA), A. Moretti (INAF-OAB), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB), E. Troja (INAF-IASFPA) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
  At 11:20:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070517 (trigger=279494). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 277.579, -62.333 which is

     RA(J2000)  =  18h 30m 19s
     Dec(J2000) = -62d 19' 56"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows two peaks with a duration of about 10 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger.
  The XRT began taking data at 11:22:43 UT, 105 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image, but analysis of down-linked data yields a position:

    RA(J2000) = 18h 30m 29.4s   
    Dec(J2000) = -62d 17' 50.8" 
  

  with an uncertainty of 5.2 arcsec (radius, 90% containment). This position is 2.4 arcmin from the BAT position.
  The UVOT is unable to observe the field of GRB070517 due to the presence of a 4th magnitude star 8 arcmin from the burst's location. The Galactic reddening in the direction of the burst is E(B-V) = 0.15.
• GCN Circular #6412
  A. C. Gilmore (Mt John Observatory of the University of Canterbury) reports:
  A total of 1200 seconds clear CCD exposures of the GRB 070517 region were taken with the 1-m f/7.7 reflector at Mt John Observatory in poor (3.5") seeing. The exposure set was centred on May 17 14:01 UT, 2.7 hours after the burst. No new object was seen to the limit of DSS-2 infrared in a 5' x 5' region approximately centred on the revised position of Vergani et al at (J2000) RA 18h 30m 30s Dec -62d 17' 50".
• GCN Circular #6413
  E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), S. D. Vergani (DIAS-DCU), on behalf of the Swift-BAT team:
  Using the data set from T-239.4 to T+302.8 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070517 (trigger #279494) (Vergani, et al., GCN Circ. 6411). The BAT ground-calculated position is RA, Dec = 277.603, -62.297 deg which is

      RA(J2000) = 18h 30m 24.7s
      Dec(J2000) = -62d 17' 49.8"
  

  with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a single peak lasting from approximately T+0 to T+10 seconds. T90 (15-350 keV) is 9.0 +- 1 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.4 to T+10.6 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.81 +- 0.24. The fluence in the 15-150 keV band is 2.6 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.65 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
• GCN Circular #6414
  S.D. Vergani (DIAS-DCU) and P. Romano (INAF-OAB) report on behalf of the Swift Team:
  We have analysed the first four orbits of Swift XRT data from GRB070517 (trigger number 279494, GCN Circ. 6411) for a total of 8.9ks. The refined XRT position is

  RA/Dec(J2000) = 18h 30m 29.0s   -62d 17' 51.7"  which is
  RA/Dec(J2000) = 277.6207   -62.2977
  

  with an uncertainty of 3.7 arcsec (radius, 90% containment). This position lies 3.5 arcsec from the XRT position and 2.4 arcmin from the BAT position given in GCN Circ. 6411 (Vergani et al.).
  The XRT PC light curve of the firts four orbits presents a flaring behaviour. A tentative fit with a power law gives a decay index alpha=0.4 +/- 0.1
  The X-ray spectrum of the PC data can be fitted using an absorbed power law (photon index = 1.95 +/-0.07) with an absorbed column density fixed to the Galactic value (8.6e20 cm^-2; Dickey & Lockman, 1990). The absorbed (unabsorbed) 0.3-10.0keV flux for this spectrum was 1.9E-12 (2.3E-12) ergs cm^-2 s^-1.
  Assuming the source continues to decay at the same rate, we predict an XRT count rate of 1.8E-2 counts/s at T+24 hours, which corresponds to an observed flux of about 9E-13 ergs cm^-2 s^-1.
  This circular is an official product of the Swift XRT team.
• GCN Report 56.1
  GCN_Report 56.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_56_1.pdf by S.D. Vergani at DIAS DCU titled: "Swift observations of GRB 070517"
• GCN Circular #6420
  D.B. Fox (Penn State), P.A. Price (Hawaii), and E. Berger (Carnegie Observatories) report:
  "We observed the refined XRT localization (Vergani & Romano, GCN 6414) of GRB 070517 (Vergani et al., GCN 6411) with the Gemini South telescope + GMOS-S, in a series of exposures beginning 03:23 UT on May 18, 2007.
  Within the refined XRT localization we identify a point-like source at coordinates R.A. 18:30:29.12, Dec -62:17:50.7 (uncertainty of <0.75" in each coordinate). This source is not present in DSS images of the region, although at an estimated brightness of r'=22.1 mag, i'=22.0 mag it lies beyond the depth of that survey. The source is detected in all of our imaged filters, g', r', i', and z'.
  We also identify a possible point-like source at coordinates R.A. 18:30:29.07, Dec -62:17:52.3 (uncertainty of <1.0" in each coordinate). This source is detected in the i' and z' bands only, with brightness i'~24.5 mag.
  Further observations will be necessary to assess the variable / afterglow nature of these sources."
• GCN Report 56.2
  GCN_Report 56.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_56_2.pdf by S.D. Vergani at DIAS&DCU titled: "Final Swift observations of GRB 070517"
• 1202.1434 from 8 Feb 12
  A. Rossi et al.: A deep search for the host galaxies of GRBs with no detected optical afterglow
  Gamma-Ray Bursts can provide information about star formation at high redshifts. Even in the absence of a optical/near-infrared/radio afterglow, the high detection rate of X-ray afterglows by swift/XRT and its localization precision of 2-3 arcsec facilitates the identification and study of GRB host galaxies. We focus on the search for the host galaxies of a sample of 17 bursts with XRT error circles but no detected long-wavelength afterglow. Three of these events can also be classified as truly dark bursts: the observed upper limit on the optical flux of the afterglow was less than expected based on the X-ray flux. Our study is based on deep R and K-band observations performed with ESO/VLT instruments, supported by GROND and NEWFIRM. To be conservative, we searched for host galaxies in an area with a radius twice the 90% swift/XRT error circle. For 15 of the 17 bursts we find at least one galaxy inside the doubled XRT error circle. In seven cases we discover extremely red objects in the error circles. The most remarkable case is the host of GRB 080207 which as a colour of R-K~4.7 mag (AB), one of the reddest galaxies ever associated with a GRB. As a by-product of our study we identify the optical afterglow of GRB 070517A. Optically dim afterglows result from cosmological Lyman drop out and dust extinction, but the former process is only equired for a minority of cases (<1/3). Extinction by dust in the host galaxies might explain all other events. Thereby, a seemingly non-negligible fraction of these hosts are globally dust-enshrouded, extremely red galaxies. This suggests that bursts with optically dim afterglows trace a subpopulation of massive starburst galaxies, which are markedly different from the main body of the GRB host galaxy population, namely the blue, subluminous, compact galaxies.