//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3977 SUBJECT: GRB 050915: Swift detection of a GRB DATE: 05/09/15 12:07:39 GMT FROM: David Palmer at LANL D. Grupe (PSU), A. Beardmore (U. Leicester), D. Burrows (PSU), J. Cummings (GSFC/NRC), K. Page (U. Leicester), D. Palmer (LANL), P. Roming (PSU), E. Rol (U. Leicester) N. Gehrels (GSFC) on behalf of the Swift Team At 11:22:42 UT, Swift-BAT triggered and located GRB050915 (trigger=155242). The BAT on-board calculated location is RA,Dec 81.714d, -28.030d {05h 26m 51s, -28d 01' 48"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve showed a multi-peak structure with at least 4 well-separated peaks and a total duration of 25 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~14 seconds after the trigger. The spacecraft slewed immediately and the XRT began observing the BAT position at 11:24:09 UT (T+87 s). The count rate was too low for an on-board centroid, but the spectrum and lightcurve strongly suggest that XRT observed a rapidly-fading X-ray source in the field. The XRT position will be available following the next ground station data dump. UVOT finds no obvious new sources in the BAT error circle in a 100 sec image starting at T+85 s. Further analysis will follow. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3978 SUBJECT: GRB 050915: ROTSE-III optical limits DATE: 05/09/15 12:09:48 GMT FROM: Sarah Yost at U.Michigan S.A. Yost, E.S. Rykoff (U Mich), B. Schaefer (Louisiana State), D.A. Smith (Guilford), T. Guver (U. Istanbul) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 050915 (Swift trigger 155242), producing images beginning 7.5 s after the GCN notice time. An automated response took the first image at 11:23:10.5 UT, 28.2 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 20 60-sec eposures. These unfiltered images are calibrated relative to USNO A2.0 (R). With the arrival of morning twilight, few further images are expected. Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.0-17.4; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 11:23:10.5 11:24:32.5 82 17.4 28.2 Y 11:24:33.4 11:29:34.4 301 18.0 111.1 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3979 SUBJECT: GRB050915: XRT position DATE: 05/09/15 13:10:48 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J.A. Kennea, D.N. Burrows, D. Grupe and C. Pagani (PSU) report on behalf of the Swift/XRT team: We have analysed ground processed data from the burst GRB050915 (BAT trigger 155242). We find a bright fading uncatalogued X-ray source at the following coordinates: RA(J2000): 05 26 44.8 Dec(J2000): -28 00 55.8 with an estimated uncertainty of 8 arcseconds (90% containment). This position lies 100 arcseconds from the BAT position reported in GCN 3977. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3980 SUBJECT: GRB050915, optical observations DATE: 05/09/15 13:38:42 GMT FROM: Arne A. Henden at AAVSO P. Kilmartin and A. Gilmore (Canterbury) report on behalf of the AAVSO International High Energy Network: We observed the localization of the Swift burst GRB050915 (Grupe et al. GCN 3977) with the 60cm OCS telescope of Mount John Observatory. 600 seconds of stacked unfiltered observations with mipoint at 050915.542 (1.6hrs after the burst) reached a limiting magnitude of CR=18.0 estimated from USNO-A2.0 stars. No new object is present by comparison with DSS2-R. Observations are continuing. The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3981 SUBJECT: GRB050915: P60 Optical Observations DATE: 05/09/15 13:54:17 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko (Caltech) and Derek B. Fox (Penn State) report on behalf of a larger collaboration: We have imaged the error circle of GRB 050915 (Grupe et al., GCN 3977) with the automated Palomar 60-inch telescope. Observations began approximately 4 minutes after the burst in the Kron R and Gunn i filters. Inside the XRT error circle (Kennea et al., GCN 3979), we find no source present. Using the USNO-B object located at 05:26:48.6, -28:00:48.9 (J2000.0, R2 = 17.90, I2 = 17.88) as a reference, we find the following 3-sigma upper limits for any point-source in the XRT error circle: Filter Int Time (s) Mean UT Tb (min) Mag --------------------------------------------------------------------------- R 540 11:41 18 > 21.0 i 540 11:43 20 > 20.5 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3982 SUBJECT: GRB 050915: Swift-BAT refined analysis DATE: 05/09/15 15:53:42 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift S. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hinshaw (GSFC-SPSYS), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), P. Meszaros (PSU), 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-100 to T+300 sec from the recent telemetry downlink, we report further analysis of Swift-BAT GRB 050915 (trigger #155242) (Grupe, et al., GCN 3977). The refined BAT ground position is RA,Dec = 81.682d,-28.010d {5h26m43.7s,-28d0'36"} [J2000] +/- 1.4 arcmin, (radius, sys+stat, 90% containment). This position is 25 arcsec from the XRT afterglow position reported in Kennea, et al. (GCN circ. 3979). The partial coding was 75%. The light curve shows about seven 2-second long peaks from T-10 to T+20 sec and one more peak at about T+43 sec. T90 (15-350 keV) is 53 +- 3 sec (estimated error including systematics). The time-averaged spectrum from T-8 to T+56 sec is well fit by a simple power law. The power law index is 1.36 +- 0.16. The fluence in the 15-150 keV band is 8.8 +- 0.9 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+13.7 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3983 SUBJECT: GRB 050915: Swift XRT refined analysis DATE: 05/09/15 18:14:14 GMT FROM: Dirk Grupe at PSU/Swift-XRT D. Grupe, J. Kennea, D. Burrows (PSU), and N. Gehrels GSFC) on report behalf of the Swift XRT team: We have analyzed the Swift XRT data of the first three orbits of GRB050915 (Grupe et al. GCN 3977, BAT trigger 155242). The new refined position based on the SDC quicklook data is: RA (J2000) = 05h26m44.6s DEC(J2000) = -28d01m01.0s This position is 5.8 arcsec away from the XRT position reported by Kennea et al. (GCN 3979) based on the preliminary data analysis and 29 arcsec from the refined BAT position (Barthelmy et al., GCN 3982). The WT data show a spectrum that can be fitted by a single power law with excess absorption above the Galactic value. The X-ray energy spectral slope is beta-x = 1.33+/-0.23. The integrated 0.3-10.0 keV Flux during the WT observation was 4.6e-10 ergs/s/cm2 (corrected for absorption). The XRT light curve started 87s after the burst and shows a rapidly decaying source after a light increased in flux at the beginning. The decay slope is alpha-1 = 3.00+/-0.14. The light curves shows a clear break in the PC mode data at 210s after the burst and flattens to a decay slope alpha-2=0.75 ±0.04. Extrapolating this light curve we estimate the 0.3-10.0 flux to be in the order of 5e-13 ergs/s/cm2 24 hours after the burst. However, this estimate does not take any late time break, which are usually observed in GRBs several hours after the burst, into consideration. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3984 SUBJECT: GRB 050915: IR Observations DATE: 05/09/15 18:34:05 GMT FROM: Josh Bloom at UC Berleley J. S. Bloom and K. Alatalo (UC Berkeley), on behalf of a larger collaboration, reports: "Starting at 2005-09-15 11:33:18 UTC, the 1.3m PAIRITEL on Mt. Hopkins began imaging the field of GRB 050915 (Swift trigger 155242; GCN 3977). In a stack of exposures amounting to 1130 sec of integration time we detect a red source at (J2000): RA 05:26:44.83 DEC -28:00:59.5 The position is uncertain to about 400 ms but may be improved with further analysis. This source appears to be consistent with the revised XRT position (Grupe et al. GCN 3983). Since the source is significantly more faint than the 2MASS detection level, we make no claims about variability at this time. Further analysis is in progress." An image will be posted to: http://astro.berkeley.edu/~jbloom/grb050915_jhk.gif This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3985 SUBJECT: GRB 050915: KAIT optical limit DATE: 05/09/15 20:10:25 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, University of California, Berkeley, on behalf of the KAIT GRB team, report: "The robotic 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory observed GRB 050915 (Swift trigger 155242; Grupe et al. GCN 3977). A series of images was automatically obtained from 11:27:32 UT (290s after the burst) to 12:21:36 UT (3534s after the burst). The sequence includes a combination of images taken with the V and I filters, as well as some that are unfiltered. We did not detect a new object in our images when compared to the DSS II images. In particular, no new object was found within the error circle of the revised XRT position (Grupe et al. GCN 3983). Our first 15s unfiltered image started at 290s after the burst has a 3-sigma limiting magnitude of about 18.2 when compared to the USNO-B1.0 catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3986 SUBJECT: GRB050915: Swift/UVOT upper limits DATE: 05/09/15 20:42:37 GMT FROM: Alexander Blustin at MSSL-UCL A. J. Blustin (UCL-MSSL), D. Grupe (PSU), T. Poole (UCL-MSSL), P. Roming (PSU), N. White (GSFC), D. Hinshaw (GSFC-SPSYS), N. Gehrels (GSFC) report on behalf of the Swift-UVOT team: The Swift/UVOT began observing the field of GRB050915 85 s after the BAT trigger (Grupe et al. GCN 3977). No new source is detected at the position of the refined XRT error circle (Grupe et al. GCN 3983) in the initial 100 s V-band image down to a 3-sigma upper limit of 19.0, or in summed exposures with any of the filters down to the following 3-sigma magnitude upper limits: Filter T_range (s) Exp (s) 3sig UL V 85-6154 1049 20.3 B 230-17031 324 20.6 U 216-12846 958 20.9 W1 203-11939 958 20.5 M2 188-6743 640 20.2 W2 246-677 59 19.6 The magnitudes are uncorrected for extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3987 SUBJECT: GRB050915B: Swift-BAT detection of a long bright burst DATE: 05/09/15 22:06:17 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift A. Falcone (PSU), A. Beardmore (U. Leicester), D. Burrows (PSU), J. Cummings (GSFC/NRC), D. Fox (PSU), N. Gehrels (GSFC), S. T. Holland (GSFC/UMBC), J. Kennea (PSU), H. Krimm (GSFC/USRA), C. Pagani (PSU), D. Palmer (LANL), A. Parsons (GSFC), E. Rol (U. Leicester), P. Roming (PSU), P. Shady (MSSL), on behalf of the Swift team: At 21:23:04 UT, Swift-BAT triggered and located GRB050915B (trigger=155284). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 219.096d,-67.405d {14h 36m 23s, -67d 24' 16"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve showed two broad bright peaks from T-10 to T+40 sec. The peak count rate was ~2800 counts/sec (15-350 keV), at T-2 sec. XRT began observing at 21:25:20 UT, 136 seconds after the BAT trigger. XRT was not able to centroid on any point source, but the downlinked lightcurve shows that a bright, fading X-ray source was present in the XRT field of view. The UVOT began observing at 21:25:18 UT, 134 seconds after the BAT trigger. No new source, with respect to the DSS, is detected in the initial 100 sec V-band image. The 5-sigma limiting magnitude, in a circular aperture of radius 6.0 arcseconds is V_lim = 17.7 mag. This magnitude is based on the preliminary V-band zero-point, measured in orbit and will require refinement with further calibration. It has not been corrected for extinction. The estimated Galactic extinction in this direction is A_V = 1.29. The UVOT image covers 25% of the 3 arcminute BAT error circle. The field is crowded. We are currently in the portion of the orbits where the spacecraft does not pass over the Malindi downlink station. Therefore, it will be ~3 hours before we have access to the full data set for the refined analyses. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3988 SUBJECT: GRB 050915b, SMARTS optical/IR observations DATE: 05/09/16 01:07:56 GMT FROM: Bethany Cobb at Yale U B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS consortium, report: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 050915b (GCN 3987, Falcone et al.), starting 2.0 hours after the burst at 2005-09-15 23:23 UT. Our optical images, in V and I, have a field of view of 6'x6' and, therefore, cover the entire GRB error circle. Our IR images, in J and K, have a smaller field of view, covering a region totaling ~6 square arcminutes in the middle of the quoted error region. Visual comparison of the optical images to the SDSS and the IR images to 2MASS frames does not reveal any new sources. Preliminary image differencing, using the ISIS image subtraction program, also does not reveal any significant variable source within the GRB error region. Analysis of this data is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3989 SUBJECT: GRB 050915B: XRT position DATE: 05/09/16 03:34:02 GMT FROM: Abe Falcone at PSU/Swift A. D. Falcone, D. N. Burrows, J. A. Kennea (PSU), W. Voges (MPE), F. Marshall (GSFC) report on behalf of the Swift XRT team: The Swift XRT began observing the long bright burst GRB 050915B (Falcone et al., GCN 3987) at 21:25:20 UT, but was unable to obtain an on-board centroid. Analysis of the initial ground-processed data finds a bright, fading, and uncataloged source at coordinates: RA(J2000) = 14:36:26.5 Dec(J2000) = -67:24:36.5 We estimate an uncertainty of 8 arcseconds (90% containment). This position lies 56 arcseconds from the BAT position reported in GCN 3987. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3990 SUBJECT: GRB 050915a: IR Transient DATE: 05/09/16 14:52:12 GMT FROM: Josh Bloom at UC Berleley J. S. Bloom (UC Berkeley) reports: "Further imaging of the field of GRB 050915a (GCNs 3977, 3979, 3983) with the PAIRITEL 1.3m began at 2005-09-16 10:58:38 UTC. We confirm that the source present in the first epoch (GCN 3984) has faded and is thus the likely IR afterglow of GRB 050915a. In particular, the mean H-band magnitude of the source during the first epoch was H=18.25 +/- 0.16. The source was undetected in the second epoch, with an approximate 3-sigma detection threshold of H(upper limit)=18.55 mag. An improved astrometric solution was obtained for the imaging on 2005-09-15 UTC, yielding a J2000 position of the IRT of: RA = 05:26:44.804 DEC = -28:00:59.27 The 1 sigma uncertainties relative to the 2MASS catalog are 0.18" and 0.09" in RA and DEC, respectively. This position is 3.2" from the revised XRT position reported by Grupe et al. (GCN 3983). We encourage deep z band and NIR imaging." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3992 SUBJECT: GRB 050915B: Swift/UVOT Upper Limits DATE: 05/09/16 20:19:47 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC GRB 050915B: Swift/UVOT Upper Limits S. T. Holland (GSFC/USRA), A. Falcone (PSU), M. Carter (UCL/MSSL), P. Smith (UCL/MSSL), and N. Gehrels (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 050915B 121 seconds after the BAT trigger (Falcone et al. GCN 3987). No new source is detected at the position of the XRT error circle (Falcone et al. GCN 3989) in the initial 100 second V-band image down to a 5-sigma upper limit of 17.5, or in summed exposures with any of the filters down to the following 5-sigma magnitude upper limits: Filter T_range (s) Exp (s) 5sig UL V 133 - 25,406 1824 19.2 B 279 - 35,461 2983 20.4 U 265 - 31,288 2381 20.2 UVW1 251 - 30,503 2972 21.0 UVM2 237 - 29,595 3006 20.7 UVW2 294 - 35,995 2609 20.8 The magnitudes are uncorrected for extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3993 SUBJECT: GRB 050915B: Swift-BAT refined analysis DATE: 05/09/16 21:14:11 GMT FROM: David Palmer at LANL J. Cummings (GSFC/NRC), M. Ajello (MPE), L. Barbier (GSFC), S. Barthelmy (GSFC), E. Fenimore (LANL), R. Fink (GSFC), N. Gehrels (GSFC), D. Hullinger (UMD), 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 full data set from T-90 to T+300 sec from the recent telemetry downlinks, we report further analysis of Swift-BAT GRB 050915B (trigger #155284) (Falcone, et al., GCN 3987). The refined BAT ground position is (RA,Dec) = 219.112, -67.412 degrees {14h 36m 26.8, -67d 24' 43"} (J2000) +-0.7 arcmin, (radius, sys+stat, 90% containment). This is within 8 arcseconds of the XRT counterpart (Falcone et al. GCN 3989). The partial coding was 53% including projection effects. The mask-weighted light curve shows a rise from T-10 seconds to a peak at T-4, dropping off to a lumpy plateau spanning T+0 to T+25, then steadily declining to zero at T+50. No further instances of emission are apparent on a 1 second timescale out to T+1200 sec. T90 (15-350 keV) is (40 +- 1) sec (estimated error including systematics). The time-averaged spectrum is well-fit by a power law with photon index 1.89 +- 0.06. The fluence in the 15-150 keV band is (3.4 +- 0.1) x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-3.1 sec in the 15-150 keV band is (2.3 +- 0.2) ph/cm2/sec. All quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3994 SUBJECT: GRB 050915b, SMARTS optical/IR observations of the XRT position DATE: 05/09/16 23:09:33 GMT FROM: Bethany Cobb at Yale U B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS consortium, report: Our ANDICAM observations reported in GCN 3988 were re-examined following the detection of the X-ray afterglow of GRB 050915b (GCN 3989, Falcone et al.). The position of the X-ray afterglow was captured in both our optical and IR images. Three sources are detected within the X-ray afterglow error region: RA DEC A) 14:36:26.04 -67:24:41.4 B) 14:36:26.35 -67:24:32.2 C) 14:36:27.30 -67:24:39.3 The first source (A) has a stellar profile and has previously been clearly detected in both the SDSS and 2MASS surveys. The other two sources (B and C) appear only slightly above the detection limits of our ANDICAM images. Sources B and C are also weakly detected in the SDSS (and possibly in 2MASS). These two sources, particularly source B, might be extended, though this is uncertain due to the low significance of their detection. The brightness of these sources does not vary significantly over our period of observation. Total summed exposure times amounted to 30 minutes in I and V and 24 minutes in J and K, with a mid-exposure time of 2005-09-15 00:01 UT (~2.6 hours post-burst). The preliminary limiting magnitudes of our images are as follows: V < 21.4 +/- 0.1 I < 21.3 +/- 0.1 J < 18.3 +/- 0.2 K < 17.8 +/- 0.2 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4001 SUBJECT: GRB 050915a: Radio Observations DATE: 05/09/19 12:14:54 GMT FROM: Dale A. Frail at NRAO P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration: "VLA observations were made toward the XRT position (GCN 3983) of GRB 050915a at a frequency of 8.46 GHz on September 18.58 UT. No radio sources are seen in the error circle above a 3-sigma level of 93 uJy. The flux density at the position of the IR transient reported by Bloom (GCN 3990) is 43 +/- 31 uJy. No further observations are planned. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 5821 SUBJECT: GRB 050915B: optical afterglow DATE: 06/11/13 22:50:34 GMT FROM: Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center D. Malesani (SISSA/ISAS & NBI-DARK), S. Covino (INAF/OABr), S. Piranomonte (INAF/OAR), L.A. Antonelli (INAF/OAR), G. Chincarini (Univ. Milano-Bicocca & INAF-OABr), P. D'Avanzo (INAF/OABr), L. Stella (INAF/OAR), and G. Tagliaferri (INAF/OABr), report on behalf of the MISTICI collaboration: We observed the field of one-year-old GRB 050915B (Falcone et al., GCNs 3987, 389) with the ESO-VLT UT2 equipped with FORS1. Observations started on 2005 Sep 16.01065 UT (2.87 hr after the GRB) and consisted in a series of 24 R-band images lasting 1 minute each. The field was observed again, in the R band, with the ESO-NTT equipped with the SuSI2 imager, with mean time 2005 Oct 1.0261 UT (15.13 days after the GRB). The field is very crowded and reddened due to the low Galactic latitude (b = -6.6 deg). Inside the XRT error circle (Moretti et al. 2006, A&A, 448, L9) there are three sources, but only two are consistent with the boresight-corrected position (Butler 2006, astro-ph/0611031 + priv. comm.), which has a 90% error radius of 1.4". One of them is clearly fading between the VLT and NTT exposures, being undetectable in the NTT images. Its coordinates (J2000) are: alpha = 14:36:26.17 delta = -67:24:32.5 It is remarkable, however, that no fading is seen for this source over the course of the VLT observation (2.87-3.66 hr after the GRB). PSF-matched profile photometry revealed that the source was constant ( = 21.68 +- 0.03) to within ~0.1 mag, with no trend for decline. In the SuSI2 image (15 days after the burst), it has R > 23.4 (3-sigma upper limit). The other object consistent with the X-ray position has coordinates alpha = 14:36:26.39 delta = -67:24:31.6 and is constant between the FORS1 and SuSI2 exposures at R = 21.2. This source, which is just 1.5" away from the afterglow, might be consistent with source "B" reported by Cobb & Bailyn. (GCN 3994). This message can be cited.