Gamma-ray Burst 040701

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE


TITLE:          GCN/HETE BURST POSITION NOTICE
NOTICE_DATE:    Sat 03 Jul 04 13:59:35 UT
NOTICE_TYPE:    HETE Ground Analysis
TRIGGER_NUM:    11548,   Seq_Num: 1
GRB_DATE:       13187 TJD;   183 DOY;   04/07/01
GRB_TIME:       46855.00 SOD {13:00:55.00} UT
TRIGGER_SOURCE: Trigger on the 2-30 keV band.
SC_-Z_RA:       314 [deg]
SC_-Z_DEC:      -35 [deg]
SC_LONG:        180 [deg East]
WXM_CNTR_RA:    311.943d {+20h 47m 46s} (J2000),
                312.016d {+20h 48m 04s} (current),
                311.125d {+20h 44m 30s} (1950)
WXM_CNTR_DEC:   -40.237d {-40d 14' 12"} (J2000),
                -40.220d {-40d 13' 12"} (current),
                -40.422d {-40d 25' 17"} (1950)
WXM_MAX_SIZE:   16.00 [arcmin] diameter
WXM_LOC_SN:     11 sig/noise (pt src in image)
WXM_IMAGE_SN:   X= 11.0 Y= 9.1 [sig/noise]
WXM_LC_SN:      X= 15.0 Y= 10.0 [sig/noise]
SUN_POSTN:      100.90d {+06h 43m 36s}  +23.06d {+23d 03' 36"}
SUN_DIST:       148.69 [deg]
MOON_POSTN:     266.52d {+17h 46m 05s}  -27.16d {-27d 09' 33"}
MOON_DIST:       39.56 [deg]
MOON_ILLUM:     99 [%]
GAL_COORDS:     1.63,-38.67 [deg] galactic lon,lat of the burst
ECL_COORDS:     303.26,-21.52 [deg] ecliptic lon,lat of the burst
COMMENTS:       HETE Message.  
COMMENTS:       Definite GRB  
COMMENTS:       WXM error box is circular; not rectangular.  
COMMENTS:       Burst_Validity flag is true  
COMMENTS:       UNTRIGGERED XRF

red DSS finding chart ps-file
GCN notice #2620
XRF040701 (=U11548): a bright XRF detected by HETE
C. Barraud, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team;
T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, K. Torii, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team;
N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams;
M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team
report:
Post-processing analysis of HETE data has revealed the presence of XRF 040701, a bright XRF. The burst was detected at 13:00:55 UT and had a duration of roughly 60 seconds. The XRF has been localized to a circle of radius 8' centered at
RA = 20h 47m 46.3s, dec = -40d 14m 13s (J2000).
Preliminary spectral analysis shows the burst can be best fit with a power law of index 2.395 +/- 0.3; the 2-25 keV energy fluence is 4.5 +/- 0.8 x 10^-7 erg/cm2.
Details of this burst can be found on the HETE web page at
http://space.mit.edu/HETE/Bursts/GRB040701
This message may be cited.
GCN notice #2621
A. de Ugarte Postigo (IAA-CSIC, Granada), P. Tristram (Univ. of Canterbury), Sasaki (Stelab, Nagoya Univ.), J. Gorosabel (IAA-CSIC), Ph. Yock (Univ. of Auckland), and A. J. Castro-Tirado (IAA-CSIC),
report:
"We have imaged the entire XRF 040701 error box provided by HETE-2 (Barraud et al. GCN #2620) with the 0.6-m telescope (+ MOA camera) at Mt.John Observatory starting on July 4.459 UT. Observations were performed with the MOA broad R-band filter with individual exposure times of 300 s. Visual comparison of the stacked first three images with the DSS-2 red plate revealed no optical counterpart candidate brighter than R~20.2."
This message may be cited.

GCN notice #2626
D.B. Fox (Caltech) reports on behalf of a larger collaboration:
"We have observed the HETE localization region for XRF040701 (Barraud et al., GCN 2620) with the Chandra X-ray Observatory + ACIS for 22.3 ksec beginning at 07:35 UT on July 9, 2004. The observation aimpoint and dither pattern provide coverage of the full 8'-radius error circle, with some decrease in exposure over the chip gaps of the ACIS-I array. A comprehensive "wavdetect" analysis provides the following catalog of sources detected with >3-sigma confidence in or near (<15") the HETE localization region (coordinates are J2000):

   #  Name                   RA            Dec           Flux  DSS?
  ==================================================================
   1  CXOU J204720.7-401941  20 47 20.696  -40 19 41.52  25.6
   2  CXOU J204816.1-401108  20 48 16.097  -40 11 08.83  11.1   Y*
   3  CXOU J204746.6-401357  20 47 46.602  -40 13 57.15   9.0
   4  CXOU J204724.0-401056  20 47 23.970  -40 10 56.07   8.8   Y
   5  CXOU J204719.1-401234  20 47 19.056  -40 12 34.33   8.5
   6  CXOU J204805.7-401823  20 48 05.696  -40 18 23.01   8.1
   7  CXOU J204751.8-401936  20 47 51.810  -40 19 36.90   8.0
   8  CXOU J204706.2-401445  20 47 06.231  -40 14 45.66   7.7
   9  CXOU J204805.3-401233  20 48 05.337  -40 12 33.74   6.1
  10  CXOU J204736.2-401623  20 47 36.158  -40 16 23.76   6.0   Y
  11  CXOU J204739.2-401748  20 47 39.249  -40 17 48.32   5.5   Y
  12  CXOU J204810.0-400721  20 48 09.981  -40 07 21.19   5.4
  13  CXOU J204740.3-401225  20 47 40.281  -40 12 25.99   4.5
  14  CXOU J204823.3-401801  20 48 23.282  -40 18 01.06   4.3
  15  CXOU J204733.1-401447  20 47 33.118  -40 14 47.48   4.1
  16  CXOU J204712.3-401112  20 47 12.288  -40 11 12.49   4.1
  17  CXOU J204810.1-401932  20 48 10.054  -40 19 32.71   4.1
  18  CXOU J204751.4-400603  20 47 51.377  -40 06 03.64   3.9
  19  CXOU J204756.5-400715  20 47 56.453  -40 07 15.01   3.9
  20  CXOU J204755.7-401347  20 47 55.713  -40 13 47.56   3.8   Y
  21  CXOU J204747.3-401516  20 47 47.349  -40 15 16.97   3.7   Y
  22  CXOU J204734.7-401042  20 47 34.678  -40 10 42.16   3.7
  23  CXOU J204809.7-401005  20 48  9.739  -40 10 05.74   3.6
  ==================================================================
  24  CXOU J204816.9-401146  20 48 16.866  -40 11 46.55   3.0
  25  CXOU J204749.9-40 627  20 47 49.854  -40 06 27.14   2.8   Y
  26  CXOU J204810.3-401256  20 48 10.259  -40 12 56.78   2.7
  27  CXOU J204736.3-401426  20 47 36.341  -40 14 26.55   2.6
  28  CXOU J204748.6-40 828  20 47 48.624  -40 08 28.52   2.5
  29  CXOU J204717.1-40 825  20 47 17.085  -40 08 25.65   2.3
  30  CXOU J204803.5-401028  20 48 03.514  -40 10 28.77   2.0
  31  CXOU J204803.3-401047  20 48 03.294  -40 10 47.68   1.8
  32  CXOU J204808.1-401842  20 48 08.121  -40 18 42.44   1.8
  33  CXOU J204748.3-401504  20 47 48.309  -40 15 04.50   1.8
  34  CXOU J204748.3-401600  20 47 48.316  -40 16 00.24   1.8
  35  CXOU J204747.8-401512  20 47 47.796  -40 15 12.32   1.7
  36  CXOU J204758.1-401735  20 47 58.094  -40 17 35.49   1.5
  37  CXOU J204728.4-401429  20 47 28.350  -40 14 29.01   1.4
  ==================================================================

Source positions have been adjusted for the observation boresight correction of (0.4" E, 0.1" S), determined by reference to DSS images of the field, and are uncertain by +/- 0.5" (two-sigma). Approximate 0.3-8.0 keV fluxes are given in units of 1E-06 photons/cm^2/s, and sources with an identifiable counterpart in the DSS are indicated ("Y"). Source #2, CXOU J204816.1-401108, is unique among these ("Y*") in that it is associated with a resolved galaxy or galaxies in the DSS, perhaps reminiscent of the host galaxy of GRB031203 (Prochaska et al. 2004, astro-ph/0402085).
We expect the X-ray afterglow of XRF040701 to be found in the brighter portions of the above catalog. In particular, most known X-ray afterglows would have F_X above the 3E-06 photons/cm^2/s division indicated in the table.
A second observation of this region is scheduled for July 18, 2004, with processed data products expected within three days of the observation. Results of the observation and a comparison of the two epochs will be reported by GCN at that time."
We acknowledge an extraordinary effort by the CXC in providing rapid processing of this challenging data-set, thereby enabling this report.

GCN notice #2627
D.D. Kelson and K. Koviak (Carnegie), with E. Berger and D.B. Fox (Caltech), report on behalf of a larger collaboration:
"We have observed the DSS-resolved galaxy associated with CXOU J204816.1-401108, Source #2 from the catalog of Fox (GCN 2626), which is potentially associated with XRF040701 (Barraud et al., GCN 2620), with the Magellan Baade 6.5-m telescope + IMACS spectrograph. We find the spectrum of this galaxy to be rich in emission lines including Hbeta4861A, [OIII]4959A,5007A, Halpha6563A, [NII]6548A,6583A, and [SII]6717,6731. The redshift is z=0.2146."
GCN notice #2628
P.B. Cameron and D.B. Fox (Caltech) with D.A. Frail (NRAO) report on behalf of a larger collaboration:
"We have made several targeted observations within and near the localization region for XRF040701 (Barraud et al., GCN 2620) with the VLA in D-configuration, on July 12, 2004, from 08:19 to 09:48:49 UT. The chief aim was to provide full coverage of the brighter part of the Chandra source catalog (Fox, GCN 2626); however, the resulting pointings provide coverage of approximately 75% of the region at X-band (8.4 GHz) and approximately 10% of the region in C-band (4.9 GHz).
We detect five sources within our coverage area, one of which is an NRAO VLA Sky Survey (NVSS) 1.4-GHz source, and none of which are coincident with Chandra sources. In addition, we have marginal (~2 sigma) detections at the positions of three Chandra sources. The following table reports the VLA source positions, frequency of detection, and flux in mJy, with uncertainties in the final digits given in parentheses. In addition, we note whether the particular source was detected in the NVSS (Y/N), which has an average RMS noise level of 0.45 mJy/beam at 1.4 GHz but technically is only complete to a declination of -40 degrees.
```
 VLA#  RA            Dec           Freq    Flux     NVSS?
 ==========================================================
   1   20 47 37.968  -40 15 44.65  8.35   1.01(10)   N
   2   20 47 07.707  -40 15 48.02  8.35   0.76(09)   Y
   3   20 47 35.965  -40 13 34.72  8.35   0.48(10)   N
   4   20 47 52.542  -40 12 36.45  8.35   0.47(10)   N
   5   20 47 29.041  -40 11 28.94  8.35   0.32(09)   N
 ==========================================================
```
We note that VLA source #1 is coincident with a bright star-like source and USNO B-1.0 object from the DSS.
The following table reports our marginal ~2-sigma detections at the positions of sources from the Chandra catalog. We give the Chandra ID number and name from Fox (GCN 2626), the frequency of observation, and the estimated flux in mJy with uncertainties in the final digits given in parentheses. In addition, we indicate whether the source has a counterpart in the DSS (Y/N).
```
 Chandra#  Name                    Freq    Flux      DSS?
 ===========================================================
    2      CXOU J204816.1-401108   8.35   0.22(10)    Y
   16      CXOU J204712.3-401112   8.35   0.19(09)    N
   25      CXOU J204749.9-400627   8.35   0.23(10)    Y 
 ===========================================================
```
Chandra source #2, which is associated with a z=0.2146 emission-line galaxy (Kelson et al., GCN 2627) has a marginal detection in X-band but not C-band."

GCN notice #2630
D.B. Fox (Caltech) reports on behalf of a larger collaboration:
"We have observed the HETE localization region for XRF040701 (Barraud et al., GCN 2620) with the Chandra X-ray Observatory + ACIS for 20.4 ksec beginning at 01:07 UT on July 18, 2004. The observation aimpoint and dither pattern are identical to that of our first-epoch observation (Fox, GCN 2626); however, a change in the roll angle has resulted in a slightly different exposure pattern due to the chip gaps of the ACIS-I array. A comprehensive "wavdetect" analysis provides the following second-epoch fluxes for sources from the catalog of our initial observation:

                                     Ep #1     Ep #2     Variability
   #   RA             Dec          Flux  Unc  Flux  Unc    %  Sigma
  ==================================================================
   1   20 47 20.696  -40 19 41.52  25.6  3.2  20.5  3.0    80  -1.6
   2   20 48 16.097  -40 11 08.83  11.1  2.1   6.4  1.7    58  -2.2
   3   20 47 46.602  -40 13 57.15   9.0  2.0   9.4  2.3   105   0.2
   4   20 47 23.970  -40 10 56.07   8.8  2.2  12.2  2.3   138   1.5
   5   20 47 19.056  -40 12 34.33   8.5  1.8   7.8  1.9    92  -0.4
   6   20 48 05.696  -40 18 23.01   8.1  1.8   7.5  1.8    93  -0.3
   7   20 47 51.810  -40 19 36.90   8.0  1.7   5.1  1.5    63  -1.7
   8   20 47 06.231  -40 14 45.66   7.8  1.8   7.7  2.0    99  -0.0
   9   20 48 05.337  -40 12 33.74   6.1  1.5   7.2  1.7   118   0.8
  10   20 47 36.158  -40 16 23.76   6.0  1.4   5.5  1.4    92  -0.3
  11   20 47 39.249  -40 17 48.32   5.5  1.4   6.2  1.6   112   0.5
  12   20 48 09.981  -40 07 21.19   5.4  1.6   3.8  1.4    71  -1.0
  13   20 47 40.281  -40 12 25.99   4.5  1.3   4.8  1.8   107   0.2
  14   20 48 23.282  -40 18 01.06   4.3  1.7   4.5  1.6   105   0.1
  15   20 47 33.118  -40 14 47.48   4.1  1.2   6.0  1.6   146   1.6
  16   20 47 12.288  -40 11 12.49   4.1  1.3   4.4  1.5   106   0.2
  17   20 48 10.054  -40 19 32.71   4.1  1.3   3.4  1.3    83  -0.5
  18   20 47 51.377  -40 06 03.64   3.9  1.4   1.6  1.0    41  -1.7
  19   20 47 56.453  -40 07 15.01   3.9  1.3   2.5  1.2    65  -1.0
  20   20 47 55.713  -40 13 47.56   3.8  1.1   4.0  1.3   104   0.1
  21   20 47 47.349  -40 15 16.97   3.7  1.1   4.2  1.3   112   0.4
  22   20 47 34.678  -40 10 42.16   3.7  1.1   1.9  0.9    53  -1.6
  23   20 48 09.739  -40 10 05.74   3.6  1.2   3.4  1.2    95  -0.1
  ==================================================================
  24   20 48 16.866  -40 11 46.55   3.0  1.1   4.1  1.2   135   0.9
  25   20 47 49.854  -40 06 27.14   2.8  1.1   2.7  1.2    96  -0.1
  26   20 48 10.259  -40 12 56.78   2.7  1.0   3.2  1.2   121   0.5
  27   20 47 36.341  -40 14 26.55   2.6  1.0   3.6  1.2   135   1.0
  28   20 47 48.624  -40 08 28.52   2.5  1.0   1.6  0.9    64  -0.9
  29   20 47 17.085  -40 08 25.65   2.3  1.0   1.5  0.0    66  -0.7
  30   20 48 03.514  -40 10 28.77   2.0  0.9   3.7  1.4   180   1.7
  31   20 48 03.294  -40 10 47.68   1.8  0.9  <1.5   -    <82 <-0.4
  32   20 48 08.121  -40 18 42.44   1.8  0.9   2.0  1.0   108   0.2
  33   20 47 48.309  -40 15 04.50   1.8  0.8  <1.5   -    <83 <-0.4
  34   20 47 48.316  -40 16 00.24   1.8  0.8   1.6  0.8    89  -0.3
  35   20 47 47.796  -40 15 12.32   1.7  0.6  <1.5   -     88  -0.4
  36   20 47 58.094  -40 17 35.49   1.4  0.8  <1.5   -   <103  <0.1
  37   20 47 28.350  -40 14 29.01   1.4  0.8  <1.5   -   <107  <0.1
  ==================================================================

As in the original catalog, fluxes here are in approximate units of 1E-06 photons/cm^2/s. Given a flux F1 and flux uncertainty U1 at the first epoch, and flux (uncertainty) F2 (U2) at the second epoch, we calculate the "Variability %" as 100*F2/F1, and the "Variability Sigma" as (F2-F1)/U1.
Our two Chandra observations take place 7.9 and 16.6 days after the burst, respectively, and we therefore expect a flux decay of approximately 53% for an afterglow power-law decay with index alpha ~ -1. The sources showing the strongest evidence for a decrease in flux of this magnitude are (in decreasing order of confidence) sources #2, #7, and #18. Source #18 is 13-arcsec outside the HETE localization.
Given the brightness of Source #2, its fading behavior, and its association with a z=0.2146 galaxy (Kelson et al., GCN 2627), this source is our preferred candidate of these three."

GCN notice #2631
E. Berger (Caltech/Carnegie), A. Gal-Yam, D.B. Fox (Caltech), I. Thompson (Carnegie), B. Schmidt, R. McNaught and B. Peterson (MSO,ANU) report on behalf of a larger collaboration:
"We used the Du Pont 2.5-m Telescope + CCD at the Las Campanas Observatory on July 16.29, 17.29, 18.28 and 19.25 UT to image an 8.8' x 8.8' field centered on the position of Chandra X-ray source CXO-2 (GCN 2626) -- suggested by Fox (GCN 2630) as a possible counterpart of XRF 040701 (GCN 2620) and associated with a galaxy at a redshift z=0.2146 (GCN 2627). All observations were performed in the R band in good seeing and weather conditions with exposure times of 20 minutes on the first three nights and 25 minutes on July 19. In addition, we obtained an R-band image of the field with the 40-in telescope at Siding Springs Observatory on July 14.
Using PSF-matched image subtraction (with the CPM/DDA algorithm, as in Gal-Yam et al. 2004, ApJ, 609, L59), we detect no sign of variability. If this is in fact the counterpart of XRF 040701, and assuming that any optical emission during this period would be dominated by a SN 1998bw-like event, associated with this XRF, then the lack of variability may not be surprising. Owing to its broad peak, SN 1998bw varied by only 0.1 mag in the rest-frame V-band during the same time. It is also possible that a SN associated with XRF 040701 is extinguished by dust and/or is fainter than SN1998bw."
GCN notice #2638
E. Pian, J. Fynbo , U. G. Joergensen, A. Levan, N. Masetti, E. Palazzi, F. Patat, E. Rol, J. Hjorth, B. Lindgren Jensen, P. Mazzali, C. Kouveliotou, K. Nomoto, E. Cappellaro, on behalf of a larger collaboration, report:
The field of source CXOU J204816.1-401108 (Fox et al. GCN 2626), detected in the error box of XRF040701 (Barraud et al., GCN 2620), was imaged with the ESO Danish 1.5m telescope at La Silla on 2004 Jul 03,15,16,17,19,23,24, Aug 4,5, and with the VLT and FORS1 on 2004 Jul 23.16, 23.33, 30.35 UT in the R band. The VLT imaging of Jul 23 was done under excellent seeing conditions (0.6").
Both R-band photometry and PSF-matched image subtraction of the galaxy at z = 0.2146 underlying CXOU J204816.1-401108 (Kelson et al. GCN 2627) rule out flux variations larger than a few hundredths of a magnitude.
Considering that we determine a lower limit of R~17.9 for the galaxy brightness, an event similar to supernova 1998bw would produce an observed variation of about 6% from explosion to maximum light. Therefore, our data appear marginally to exclude a supernova similar to 1998bw (see also Berger et al. GCN 2631), but not a weaker one, like SN2002ap or SN1994I.
A 2hr VLT+FORS1+300V spectrum of the galaxy taken on Jul 23 does not reveal conspicuous supernova features. The 2 galaxies located at ~4" West and ~6" South of the galaxy underlying CXOU J204816.1-401108 have redshifts 0.215 and 0.17, respectively.
This message can be cited.
GCN notice #2824
S. Kulkarni, A. Soderberg and D. Fox report on behalf of the Caltech/Carnegie/NRAO collaboration:
"As part of our large HST program on GRBs and XRFs, we have used ACS to observe the fields of XRF 040701 and XRF 040812. Observations were taken in the F625W (r) and F775W (i) filters 39 and 60 days after the burst (XRF040701) and 32 and 54 days after the burst (XRF040812). Comparison of the two epochs for each XRF does not reveal a variable source within the 1-arcsec position of the putative Chandra X-ray afterglow candidates (GCNs 2630 and 2655 for XRFs 040701 and 040812, respectively). Our 3-sigma limits are the following:
```
	XRF		Filter		Limit:
 	==============================================
  	040701		F625W		27.5
			F775W		27.0
	040812		F625W		27.5
			F775W		27.0
```

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Jochen Greiner, last update: 19-Oct-2004 [Disclaimer]