Gamma-ray Burst 060424

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Apr 06 04:16:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     206773,   Seg_Num: 0
GRB_RA:            7.355d {+00h 29m 25s} (J2000),
                   7.439d {+00h 29m 45s} (current),
                   6.689d {+00h 26m 45s} (1950)
GRB_DEC:         +36.820d {+36d 49' 11"} (J2000),
                 +36.855d {+36d 51' 17"} (current),
                 +36.543d {+36d 32' 37"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5058 [cnts]    Image_Peak=250 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       30219 [cnts]
BKG_TIME:        15366.84 SOD {04:16:06.84} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13849 TJD;   114 DOY;   06/04/24
GRB_TIME:        15379.52 SOD {04:16:19.52} UT
GRB_PHI:         -64.17 [deg]
GRB_THETA:        29.65 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     21.21 [sigma]
IMAGE_SIGNIF:    10.10 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +7 -100  +0 -84  +1 
SUN_POSTN:        31.61d {+02h 06m 27s}  +12.80d {+12d 48' 12"}
SUN_DIST:         32.35 [deg]   Sun_angle= 1.6 [hr] (West of Sun)
MOON_POSTN:      346.16d {+23h 04m 39s}   -7.70d {-07d 41' 50"}
MOON_DIST:        48.81 [deg]
MOON_ILLUM:      18 [%]
GAL_COORDS:      118.04,-25.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       22.72, 30.60 [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 = 100.49,-6.97 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Apr 06 04:19:53 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     206773,   Seg_Num: 0
GRB_RA:            7.355d {+00h 29m 25s} (J2000),
                   7.439d {+00h 29m 45s} (current),
                   6.689d {+00h 26m 45s} (1950)
GRB_DEC:         +36.820d {+36d 49' 11"} (J2000),
                 +36.855d {+36d 51' 17"} (current),
                 +36.543d {+36d 32' 37"} (1950)
GRB_DATE:        13849 TJD;   114 DOY;   06/04/24
GRB_TIME:        15379.52 SOD {04:16:19.52} UT
TRIGGER_INDEX:   148
GRB_PHI:         -64.17 [deg]
GRB_THETA:        29.65 [deg]
DELTA_TIME:      12.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     21.21 [sigma]
IMAGE_SIGNIF:    10.10 [sigma]
LC_URL:          sw00206773000msb.lc
SUN_POSTN:        31.62d {+02h 06m 28s}  +12.80d {+12d 48' 15"}
SUN_DIST:         32.36 [deg]   Sun_angle= 1.6 [hr] (West of Sun)
MOON_POSTN:      346.19d {+23h 04m 46s}   -7.68d {-07d 40' 54"}
MOON_DIST:        48.78 [deg]
MOON_ILLUM:      18 [%]
GAL_COORDS:      118.04,-25.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       22.72, 30.60 [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 = 100.49,-6.97 [deg].

GCN Circular #5000
E. Rol (U Leicester), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 04:16:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060424 (trigger=206773). Swift was not able to slew to the burst due to its proximity to the Sun. The BAT on-board calculated location is RA,Dec 7.355, +36.820 {00h 29m 25s, +36d 49' 11"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a small spike on top of a weak peak starting about T-5 sec to about T+5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Because of the Sun observing constraint, there will not be any XRT or UVOT follow-up observations on this burst for at least 24 days.
GCN Circular #5001
D. Hullinger (BYU-Idaho), L. Barbier (GSFC), S.D. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-240 to T+734 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060424 (trigger #206773) (E.Rol, et al., GCN 5000). The BAT ground-calculated position is RA,Dec = 7.354,+36.789 deg {0h 29m 25.1s,+36d 47' 20.7"} (J2000) +- 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%.
The mask-weighted lightcurve has 5 main peaks at T-18, T-4, T+2, T+9, and T+20 sec with widths ranging from 4 to 8 sec FWHM. T90 (15-350 keV) is 37 +- 2 sec (estimated error including systematics). Swift did not automatically slew to this new burst because of the Sun observing constraint. It did slew to a pre-planned observing target at T+160 sec and the new burst went out of the BAT FOV at T+240 sec.
The time-averaged spectrum from T-19.6 to T+20.6 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.19. The fluence in the 15-150 keV band is 6.8 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.11 sec in the 15-150 keV band is 1.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5003
Christina C. Thoene, Kim Nilsson, Brian L. Jensen, Johan Fynbo (Dark Cosmology Centre) report
We observed the BAT error circle of GRB060424 (GCN 5000) in I with the NOT and ALFOSC on La Palma, starting at UT 05:03:40 at very high airmass. Inside the BAT revised error circle (GCN 5001) we detect a new source at the position (J2000)
```
RA = 00:29:25.8
Dec =+36:47:58.7
```
The preliminary I magnitude obtained from 5x300s stacked images with a mean time of about 1h after the burst is
I = 19.1 (compared to a nearby USNO star)
The source is not visible in observations obtained the following night and therefore likely to be the afterglow of GRB060424
A finding chart will be available soon at: http://www.astro.ku.dk/~brian_j/grb/grb060424.178/

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Jochen Greiner, last update: 25-Apr-2006 [Disclaimer]