GRB120422A

This page lists all entries on GRB120422A in GRBweb

Summary IPN Swift GCN 13243 GCN 13244 GCN 13245 GCN 13246 GCN 13247 GCN 13248 GCN 13249 GCN 13250 GCN 13251 GCN 13252 GCN 13253 GCN 13254 GCN 13255 GCN 13256 GCN 13257 GCN 13258 GCN 13259 GCN 13260 GCN 13263 GCN 13267 GCN 13269 GCN 13273 GCN 13275 GCN 13276 GCN 13277 GCN 13278 GCN 13279 GCN 13281 GCN 13288 GCN 18183

Summary table
Variable Value Source
T0 7:12:03 UTC GCN_circulars,Swift Det
ra 136.9100° Swift
decl 14.0188° Swift
pos_error 1.29e-04° Swift
T90 5.35 s Swift
T90_start 7:12:03 UTC Swift
fluence 2.30e-07 erg/cm² Swift
redshift 0.2830
T100 5.35 s
GBM_located False
mjd 56039.30003472222 GCN_circulars,Swift Det
IPN table
GRB_name GRB120422A
ra 136.9292°
decl 14.0000°
pos_error 5.00e-02°
redshift 0.2830
Swift table
GRB_name GRB120422A
t_trigger 7:12:03 UTC
ra 136.9100°
decl 14.0188°
pos_error 1.29e-04°
T90 5.35 s
fluence 2.30e-07 erg/cm²
redshift 0.2800
GCN 13243 table
GRB_name GRB120422A
GCN_number 13243
Detection_method Swift Det
t_trigger 7:12:03 UTC
ra 136.9290°
decl 14.0060°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13243 SUBJECT: GRB 120422A: Swift detection of a burst DATE: 12/04/22 07:22:49 GMT FROM: David Palmer at LANL E. Troja (NASA/GSFC/ORAU), V. D'Elia (ASDC), C. Guidorzi (U Ferrara), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), O. M. Littlejohns (U Leicester), A. Melandri (INAF-OAB), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 07:12:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120422A (trigger=520658). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 136.929, +14.006 which is RA(J2000) = 09h 07m 43s Dec(J2000) = +14d 00' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single complex peak structure with a duration of about 10 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 07:13:38.7 UT, 95.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 136.91183, 14.01873 which is equivalent to: RA(J2000) = 09h 07m 38.84s Dec(J2000) = +14d 01' 07.4" with an uncertainty of 4.2 arcseconds (radius, 90% containment). This location is 75 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.71 x 10^20 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 3.12e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 104 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN 13244 table
GRB_name GRB120422A
GCN_number 13244
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13244 SUBJECT: GRB 120422A: Faulkes Telescope North observations DATE: 12/04/22 08:09:59 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), J. Japelj (U. Ljubljana), A. Melandri (INAF-OAB) on behalf of a larger collaboration report: "The 2-m Faulkes Telescope North robotically followed up GRB 120422A (D'Elia et al., GCN Circ. 13243) at 07:18:38 UT, corresponding to 6.6 min after the GRB trigger time. In the XRT error circle, in a 3x10s frame we do not find any source brighter than R=18.4 mag, calibrated against nearby USNOB-1 field stars.
GCN 13245 table
GRB_name GRB120422A
GCN_number 13245
Detection_method Swift-BAT Det
ra 136.9099°
decl 14.0188°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13245 SUBJECT: GRB 120422A: Gemini observations DATE: 12/04/22 10:44:59 GMT FROM: Antonino Cucchiara at UCSC/UCO Lick A. Cucchiara (UCSC/UCO Lick), A. Levan (U Warwick), D. B. Fox (PennState), N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration reports: On April 22.33 UT (~50 minutes after the BAT trigger) we observed the field of GRB 120422A (Troja et al., GCN 13243) using GMOS Spectrograph on the Gemini-North 8-m telescope. In our acquisition image of 240s in i' band an optical candidate was identified at: RA: 09:07:38.38 Dec: +14:01:07.5 with an uncertainty of 0.3" in each direction. Using three SDSS stars in the field we estimate a magnitude of i'=19.03 +- 0.15 We also noticed just outside the XRT error circle the presence of the SDSS (DR8) galaxy SDSS J090738.51+140108.3. A subsequent spectrum of 2x900s, covering the wavelength range 6000-10000 does not present evident absorption features. If the SDSS galaxy is associated with GRB 120422A then its brightness would suggest a moderately low redshift (z<1). Further analysis is in progress. We thank the Gemini-North staff for their prompt support.
GCN 13246 table
GRB_name GRB120422A
GCN_number 13246
Detection_method Swift-BAT Det
ra 136.9150°
decl 13.9740°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13246 SUBJECT: GRB 120422A: Swift-BAT refined analysis DATE: 12/04/22 13:48:29 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), E. Troja (NASA/GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+224 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120422A (trigger #520658) (Troja, et al., GCN Circ. 13243). The BAT ground-calculated position is RA, Dec = 136.915, 13.974 deg, which is RA(J2000) = 09h 07m 39.7s Dec(J2000) = +13d 58' 27.1" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%. The mask-weighted light curve shows a single peak starting at ~T-3 sec, peaking at ~T+1, and ending at ~T+20 sec. There is a low-significance peak (~3 sigma) at T+45 to T+65. T90 (15-350 keV) is 5.35 +- 1.4 sec (estimated error including systematics). The time-averaged spectrum from T-0.80 to T+6.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.19 +- 0.24. The fluence in the 15-150 keV band is 2.3 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.86 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/520658/BA/
GCN 13247 table
GRB_name GRB120422A
GCN_number 13247
Detection_method Swift-XRT Det
ra 136.9103°
decl 14.0182°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13247 SUBJECT: GRB 120422A: Enhanced Swift-XRT position DATE: 12/04/22 15:12:10 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1079 s of XRT Photon Counting mode data and 2 UVOT images for GRB 120422A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 136.91027, +14.01822 which is equivalent to: RA (J2000): 09h 07m 38.46s Dec (J2000): +14d 01' 05.6" with an uncertainty of 1.9 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 13248 table
GRB_name GRB120422A
GCN_number 13248
Detection_method Swift-UVOT Det
ra 136.9101°
decl 14.0188°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13248 SUBJECT: GRB 120422A: A Swift/UVOT Detection DATE: 12/04/22 18:23:37 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (MSSL-UCL) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120422A 104 s after the BAT trigger (Troja et al., GCN Circ. 13243). A source consistent with the XRT position (Beardmore et al., GCN Circ. 13247) is detected in the summed UVOT exposures at position: RA (J2000) = 136.91012 deg. = 09:07:38.4 Dec (J2000) = +14.018782 deg. = +14:01:07.6 with an estimated uncertainty of 1". Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 104 254 147 20.39 +/- 0.27 white 857 1007 147 20.51 +/- 0.29 white 5251 6888 393 20.25 +/- 0.15 v 5662 5862 1082 >19.4 b 5047 6683 393 >20.7 u 262 512 246 19.89 +/- 0.32 u 4842 6478 393 20.00 +/- 0.31 w1 4637 12807 1039 19.84 +/- 0.18 m2 5867 6067 197 19.21 +/- 0.28 m2 11245 12145 886 19.36 +/- 0.14 w2 5457 7032 332 18.98 +/- 0.16 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN 13249 table
GRB_name GRB120422A
GCN_number 13249
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13249 SUBJECT: GRB 120422A: Swift-XRT refined Analysis DATE: 12/04/22 19:23:05 GMT FROM: Phil Evans at U of Leicester B. Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and E. Troja report on behalf of the Swift-XRT team: We have analysed 13 ks of XRT data for GRB 120422A (Troja et al. GCN Circ. 13243), from 101 s to 30.1 ks after the BAT trigger. The data comprise 307 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 13247). The light curve can be modelled with an initial power-law decay with an index of alpha=6.22 (+0.30, -0.28), followed by a break at T+373 s to an alpha of 0.30 (+0.11, -0.14). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 4.5 (+0.4, -0.3). The best-fitting absorption column is 2.5 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 3.7 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 1.9 x 10^-11 (1.7 x 10^-10) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 2.5 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 3.7 x 10^20 cm^-2 Excess significance: 8.5 sigma Photon index: 4.5 (+0.4, -0.3) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00520658. This circular is an official product of the Swift-XRT team.
GCN 13250 table
GRB_name GRB120422A
GCN_number 13250
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13250 SUBJECT: GRB 120422A: Zadko observatory - Gingin optical observations DATE: 12/04/22 20:14:59 GMT FROM: Alain Klotz at CESR-CNRS A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), B. Gendre (ASDC/INAF-OAR), M. Boer (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 120422A detected by SWIFT (trigger 520658) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 3.6h and finished 4.8h after the GRB trigger. Weather conditions were good but a poor seeing of 3.5 arcsec does not allow to separate the GRB afterglow (Cucchiara et al. GCNC 13245) and the SDSS galaxy J090738.51+140108.3. We added the r, g, i SDSS images to create an equivalent of the Zadko unfiltered image. The star R=16.37 at ra=136.9080750 dec=+14.0119528 J2000 was used as reference. The flux ratio of the reference star and the galaxy shows that an additional component at R=21.1 should be present in the galaxy on the Zadko image. start end Rmag dmag filter (h) (h) 3.6 4.8 21.1 0.2 CR
GCN 13251 table
GRB_name GRB120422A
GCN_number 13251
Detection_method Swift Other
redshift 0.2800
Circular_text TITLE: GCN CIRCULAR NUMBER: 13251 SUBJECT: GRB 120422A: Gemini redshift of candidate host DATE: 12/04/22 20:18:05 GMT FROM: Nial Tanvir at U.Leicester N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), A. Cucchiara (UCSC/UCO Lick) & D. B. Fox (Penn State) report on behalf of a larger collaboration: Further analysis of the Gemini/GMOS spectrum of the nearby galaxy reported by Cucchiara et al. (GCN 13245) revealed emission lines of Ha, OIII(5007/4959) and Hb at a common redshift of z=0.28. At this redshift, the impact parameter of the afterglow is about 8kpc, which would be a rather large offset for a long-GRB, but certainly possible. If the galaxy is the host, then the absence of absorption lines in the afterglow spectrum would not be too surprising, given the weakness of expected lines in the observed wavelength range. However, it would also make it one of the lowest redshift GRBs so far detected by Swift, and so an important target for further follow-up.
GCN 13252 table
GRB_name GRB120422A
GCN_number 13252
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13252 SUBJECT: GRB 120422A: NOT optical observations DATE: 12/04/23 01:25:22 GMT FROM: Dong Xu at Weizmann Inst S. Schulze (U. Iceland), D. Malesani (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), A. J. Levan (U Warwick), P. Jakobsson (U. Iceland), E. Wuyts (KIPAC Chicago) report on behalf of a larger collaboration: We observed the field of GRB 120422A (Troja et al., GCN 13243) with the Nordic Opitcal Telescope (NOT) equipped with MOSCA. We obtained 12 x 300 s I-band images. Observations started at 20:54 UT on April 22 (i.e., 13.3 hrs after the burst). We clearly detected the source reported in Cucchiara et al. (GCN 13245) in all individual images. There was no significant fading during observations. The source has an I-band brightness of 21.7 mag (Vega magnitude) in the stacked image. This value is not corrected for foreground extinction and calibrated with the #1039-0167772 star (I = 18.98 mag) in the USNO B1 catalogue.
GCN 13253 table
GRB_name GRB120422A
GCN_number 13253
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13253 SUBJECT: GRB 120422A: Xinglong TNT optical upper limit DATE: 12/04/23 02:38:19 GMT FROM: L.P. Xin at NAOC L. P. Xin, J. Y. Wei, Y. L. Qiu, J. Wang, J. S. Deng, C. Wu, X. H. Han on behalf of EAFON report: We began to observe GRB 120422A (Troja et al., GCN 13243) with Xinglong TNT telescope in R-band at 11:37:41(UT), 4.45 hours after the burst under the bad weather condition. The optical counterpart ( Cucchiara et al. GCN 13245; Kuin et al. GCN 13248; Klotz et al. GCN 13250; Schulze et al. GCN 13252) was not detected in our combined image. The upper limit was estimated about 19.5 mag in R band at the mean time of 5.15 hours after the burst, calibrated against the USNO B1.0 R2mag. This message may be cited. For more information about Xinglong GRBs Follow-up observations, please visit the website: http://www.xinglong-naoc.org:8080/grb/index.html We thank Liang Ma for performing these observations.
GCN 13254 table
GRB_name GRB120422A
GCN_number 13254
Detection_method VLA Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13254 SUBJECT: GRB 120422A: EVLA Detection DATE: 12/04/23 06:34:07 GMT FROM: Ashley Zauderer at CfA Ashley Zauderer, Edo Berger and Tanmoy Laskar (Harvard) report: "We observed the position of GRB 120422A (GCN 13243) with the EVLA at 6 GHz and 22 GHz beginning 2012 Apr 23.09 (0.8 d after the burst). We detect a 5- and 3-sigma source (for 6 and 22 GHz, respectively) consistent with the Swift-XRT position (GCN 13247) and the UVOT position (GCN 13248). The position of the radio source is RA 09:07:38.42 (+/- 0.01) DEC +14:01:07.1 (+/- 0.2) Followup observations are planned."
GCN 13255 table
GRB_name GRB120422A
GCN_number 13255
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13255 SUBJECT: GRB 120422A: Super-LOTIS early observations DATE: 12/04/23 06:49:46 GMT FROM: Peter A. Milne at Super-LOTIS Adria C. Updike (Dickinson College), Dieter H. Hartmann (Clemson University), Peter A. Milne (Steward Observatory), and G. Grant Williams (MMTO) report: We observed the field of GRB 120422A (Troja et al., GCN 13243) with the 0.6m Super-LOTIS telescope at KPNO beginning 77 seconds after the trigger under good conditions. We do not detect the OT (Cucchiara et al., GCN 13245; Kuin & Troja, GCN 13248) in the R band. Limiting magnitudes are given below, compared to the USNO B1.0 catalog. midtime (s) stack limiting mag ---------------------------------------------------- 126 4 x 5s 16.4 233 5 x 10s 16.9 557 5 x 60s 19.0
GCN 13256 table
GRB_name GRB120422A
GCN_number 13256
Detection_method GROND
Circular_text TITLE: GCN CIRCULAR NUMBER: 13256 SUBJECT: GRB 120422A GROND observations DATE: 12/04/23 07:42:24 GMT FROM: Marco Nardini at MPE M. Nardini (Uni. Milano-Bicocca), S. Schmidl (TLS Tautenburg), J.Greiner (MPE Garching), and D.A. Kann (TLS Tautenburg) report on behalf of the GROND team: We observed the field of GRB 120422A (Swift trigger 520658, Troja et al., GCN #13243) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observations started on April 22, 2012, at 23:39 UT, 16.5 hr after the GRB trigger, and continued for 3 hours. They were performed at an average seeing of 1.45" and at an average airmass of 1.45. Based on 49 min of total exposures in g'r'i'z' and 100 min in JHK we found a blue source consistent with the afterglow position reported by Kuin et al. (GCN #13248) and Cucchiara et al. (GCN #13245). In g'r'i'z'J we measure a separation of about 1.6" from the SDSS (DR8) galaxy SDSS J090738.51+140108.3 cited by Cucchiara et al., even if we notice that this value is just slightly larger than the measured seeing. At the position of afterglow candidate we measure the following magnitudes (in the AB system) g' = 21.68 +- 0.05 AB mag, r' = 21.59 +- 0.05 AB mag, i' = 21.3 +- 0.1AB mag calibrated against SDSS field stars and not corrected for Galactic foreground reddening of E(B-V)=0.035 (Schlegel et al. 1998). We note that the i'-band measurement is significantly contaminated by the underlying candidate host galaxy and thus has to be considered preliminary. Nonetheless, a comparison with the earlier observations reported by Cucchiara et al. (GCN #13245) indicate a fading of at least 2 mag and thus confirms the afterglow nature of the source.
GCN 13257 table
GRB_name GRB120422A
GCN_number 13257
Detection_method Optical
redshift 0.2830
Circular_text TITLE: GCN CIRCULAR NUMBER: 13257 SUBJECT: GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart DATE: 12/04/23 09:13:23 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst S. Schulze (Univ. Iceland), A. J. Levan (Univ. Warwick), D. Malesani (DARK/NBI), J. P. U. Fynbo (DARK/NBI), N. R. Tanvir (Univ. Leicester), B. Milvang-Jensen (DARK/NBI), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), V. D'Elia (ASI/ASDC and INAF/OAR), J. Sollerman (OKC, Stockholm), J. Hjorth (DARK/NBI), report on behalf of the X-shooter GRB GTO collaboration: We observed the optical counterpart of GRB 120422A (Troja et al., GCN 13243; Cucchiara et al., GCN 13245) with the ESO VLT equipped with the X-shooter spectrograph. Observations started on 2012 April 22.99 UT (16.5 hr after the GRB), for a total exposure time of 80 min in each of the UVB, VIS, and NIR arms, covering the wavelength range 3000-25000 AA. The slit was aligned so to cover both the galaxy at z = 0.28 present in the SDSS (Cucchiara et al., GCN 13245; Tanvir et al., GCN 13251) and the GRB optical counterpart (Cucchiara et al., GCN 13245). We detect a plethora of nebular emission lines from the candidate host galaxy, including [O II], [O III], Balmer lines up to Hzeta, [N II], [S II], at a common redshift z = 0.283, thus confirming the results of Tanvir et al. (GCN 13251). The trace of the GRB counterpart is rather blue (see also Nardini et al., GCN 13256), and we detect Mg II at z = 0.283 in absorption. No further absorption features are visible. We also note that the spatial extent of the brightest emission lines from the SDSS galaxy encompasses the position of the GRB counterpart, indicating nebular emission at z = 0.283 at the GRB position. While a chance superposition cannot be excluded, we note that the lack of absorption features at z > 0.283 would require a very tenuous environment at the GRB location. Furthermore, the UVOT detection in all the UV filters (Kuin & Troja, GCN 13248) implies a low redshift z <~ 1.3. Last, we note that the UVOT photometry at t ~ 5 ks after the burst reveals a very blue spectrum, which is not typical of GRB afterglows, but is reminiscent of the very blue early emission of GRB 060218 (Campana et al. 2006, Nature, 442, 1008). We thus conclude that the GRB is also likely at z = 0.283. Using the gamma-ray fluence reported by Barthelmy et al. (GCN 13246), at z = 0.283 the isotropic-equivalent energy release of GRB 120422A is ~4.4*10^49 erg, which is typical of local GRBs, often associated with supernovae. We encourage photometric and spectroscopic follow-up to detect the emergence of a supernova, or lack thereof. We acknowledge the excellent support of the ESO observing staff in Paranal, in particular Henri Boffin and Giovanni Carraro. We thank Nino Cucchiara for providing us with a finding chart from the Gemini observation (GCN 13245).
GCN 13258 table
GRB_name GRB120422A
GCN_number 13258
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13258 SUBJECT: GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval DATE: 12/04/23 22:37:04 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made observations of Swift trigger 520658 (Troja et al., GCN 13243). The burst location was within the field of our wide-field monitor located in Maui, HI, which began a 10 s integration of the location at 07:12:06.81 UT, 3.2 s after the Swift trigger time and during the gamma-ray emitting interval. The optical counterpart (Cucchiara, et al., GCN 13245, and Kuin et al., GCN 13248) was not detected above our 3-sigma limiting magnitude of 10.3 based on a comparison of our unfiltered image to the Tycho-2 V-band catalog. Our narrow-field instruments in Los Alamos, NM, began imaging at 07:12:55.49 UT, 51.8 s after the Swift trigger and 5.7 s after receiving the GCN packet. The initial 5 s exposure shows no counterpart to a 3-sigma limiting magnitude of 16.6 when compared to the USNO-B1 R-band. The following table gives a sample of our observations. The start time is given as the seconds between the start of the exposure and the initial Swift trigger time. start(s) exp(s) mag limit -------------------------------- -16.8 10.0 >10.3 3.2 10.0 >10.3 22.7 10.0 >10.3 51.8 5.0 >16.6 60.8 5.0 >16.9 149.8 10.0 >17.4 437.2 30.0 >17.9
GCN 13259 table
GRB_name GRB120422A
GCN_number 13259
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13259 SUBJECT: GRB 120422A: JCMT SCUBA-2 sub-mm observation DATE: 12/04/24 01:16:41 GMT FROM: Ian Smith at Rice U I.A. Smith (Rice U.), R.P.J. Tilanus (JAC), N.R. Tanvir (U. of Leicester), D.A. Frail (NRAO) report: We observed the counterpart to GRB 120422A (Troja et al., GCN Circ. 13243) using the SCUBA-2 sub-millimeter continuum camera on the James Clerk Maxwell Telescope. The observation started at 07:53 UT on 2012-04-22, corresponding to 41 minutes after the burst trigger. Exposures totaling 1.5 hours were made in moderate weather conditions. No source was detected, with a preliminary RMS of 2.8 mJy at 850 microns. We thank William Montgomerie for his prompt support of these observations.
GCN 13260 table
GRB_name GRB120422A
GCN_number 13260
Detection_method Optical
redshift 0.2830
Circular_text TITLE: GCN CIRCULAR NUMBER: 13260 SUBJECT: GRB 120422A: 272 GHz observations from SMA DATE: 12/04/24 16:44:53 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC S. Martn (ESO), G. Petitpas (SMA), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) on behalf of a larger collaboration report: We have observed the field of GRB 120422A (Troja et al. GCN 13243) with the Submillimeter Array (SMA, Hawaii, U.S.A.). Observations, with mean epoch 23.19 April 2012 (21.4 hours after the burst), were carried out with 8 antennas in very extended configuration at an average frequency of 272 GHz under excellent weather conditions (optical depth at 225 GHz ~0.03, equivalent to PWV~0.5mm). The short 57 minutes integration on source yielded a preliminary r.m.s. of 1.2 mJy. No source is detected at the position of the optical (Cucchiara et al. GCN 13245) and radio (Zauderer et al. GCN 13245) afterglow down to a 3-sigma limit of 3.6 mJy. Considering the low redshift of 0.283 (Schulze et al. GCN 13257), this limit places GRB 120422A at the faint end of the luminosity distribution of mm/submm GRB afterglows (see Fig. 8 of de Ugarte Postigo et al. 2012, A&A, 538, 44), consistent with what has been seen for other local low-luminosity GRB/SN. We acknowledge the excellent support of the SMA staff.
GCN 13263 table
GRB_name GRB120422A
GCN_number 13263
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 13263 SUBJECT: GRB 120422A: MITSuME Ishigakijima upper limit DATE: 12/04/26 15:20:07 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 120422A (Troja et al., GCNC 13243) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2012-04-22 13:03:25 UT (~5.9 h after the burst). We could not detect the previously reported afterglow (Cucchiara et al., GCNC 13245) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ---------------------------------------------------------------------- 0.27008 13:40:57 2880.0 >21.5 >21.3 >19.5 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]
GCN 13267 table
GRB_name GRB120422A
GCN_number 13267
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13267 SUBJECT: GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy DATE: 12/04/27 16:45:33 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech), A. Cucchiara (UCO/Lick), S. B. Cenko (UC Berkeley), A. J. Levan (Warwick), S. R. Kulkarni, S. Ben-Ami, and Y. Cao (Caltech) report: We conducted a second epoch of imaging at the position of GRB 120422A (Troja et al., GCN 13243) with GMOS-N on Gemini-North starting at 05:42 UT on 2012-04-26 in each of the griz filters. Seeing conditions were excellent (0.7"), cleanly resolving the transient previously identified by Cucchiara et al. (GCN 12345) from its putative host galaxy. A curved bridge of emission connects the transient with the host, suggesting it occurred either in a spiral arm (however no counter-arm is visible on the far side of the galaxy) or within an interacting companion. An image is posted to: http://www.astro.caltech.edu/~dperley/gcn/120422a/120422a_gmos.png The transient has clearly faded since the last observations, and is now at r = 22.05 +/- 0.09 mag, i = 22.31 +/- 0.07 mag (using a 0.7" radius aperture and calibrating relative to SDSS standards, with the uncertainties due almost entirely to the systematics of the color comparison). This would indicate a relatively blue color. However, the (nearly contemporaneous) g-band flux lies approximately 1 magnitude below a simple extrapolation of the r-i color, indicating that the SED peaks in or near the r-band range. As previously noted by Schulze et al. (GCN 13257) on the basis of the blue UVOT color, this type of SED is very unusual for traditional GRB afterglows (which normally are power-laws in the optical band) but similar properties have been seen at early times in GRBs 060218 (e.g. Campana et al., Nature 442:1008), as well as GRBs 100316D (Starling et al. 2011, MNRAS 411:2792), and 101225 (Thne et al. 2011, Nature 480:72). We suggest that the apparent color evolution of the peak wavelength of the transient from the UV to the optical and NIR is likely to continue in subsequent days, and encourage multi-band photometric follow-up as well as spectroscopy. Additionally, on the night of 2012-04-27 UT we acquired 30 minutes of spectroscopy using LRIS on the Keck 10m telescope. A preliminary flux calibration of the spectrum shows a similar signature as evident in the photometry, with a pronounced, smooth peak around 6500 Angstroms. No obvious absorption or emission features are evident except for the narrow emission lines from the underlying host, previously mentioned by Tanvir et al. (GCN 13251) and Schulze et al. (GCN 13257). In particular, we do not yet recognize any broad supernova signatures. Further observations are planned.
GCN 13269 table
GRB_name GRB120422A
GCN_number 13269
Detection_method Other
ra 136.9102°
decl 14.0182°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13269 SUBJECT: GRB 120422A, the review of the sky area in plate archives DATE: 12/04/28 08:26:21 GMT FROM: Valentyna Golovnya at Main Astro Obs,Kyiv We have undertaken the review of the sky area in vicinity of GRB 120422A (A.P. Beardmore et al. GCN Circ.13247) on astronegatives, collected in Ukrainian NAS Main astronomical observatory plate archive (1976-1996). All the plates with the possible object appearance are digitized using Microtek ScanMaker 9800XL TMA and Epson Expression 10000XL flatbed scanners and have been placed into Golosiiv Plate Archive database DBGPA with open access to them. The list of plates is given in the table: YYYYMMDD/TimeUT --Plates-- Ex. LimM Star USNOA2 19921201/022312 GUA040C002050A 18.0 15.05 0975-06157849 19921201/025107 GUA040C002051 18.0 15.95 1575-06157752 19930114/232017 GUA040C002089A 22.5 15.05 0975-06157849 19930114/235112 GUA040C002090 22.5 15.05 0975-06157849 Plates: GUA040C the plates archive identifier of DWA (D/F=400/2000, M=103"/mm) of the Ukrainian NAS Main Astro obs. (Marsden's number - 83) the plate number [1]. Ex. - Duration of the maximum exposure (minutes). LimM - Limited V mag, derived in the 26 minutes area around the location given in A.P. Beardmore et al. GCN Circ.13247: RA(J2000): 09h 07m 38.46s, Dec(J2000): +14d 01' 05.6" Star USNOA2 - Comparison star. The preview images of 4 areas together with the 26x26 min.of arc area from SkyMap can be found in http://gua.db.ukr-vo.org/img/grb/120422A/index.html The images with full resolution are available via e-mail on demand. References: 1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0), http://gua.db.ukr-vo.org
GCN 13273 table
GRB_name GRB120422A
GCN_number 13273
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13273 SUBJECT: GRB 120422A: optical observations DATE: 12/04/29 17:45:14 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev, K. Antonyuk (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 120422A (Troja et al., GCN 13243) with AZT-11 telescope of CrAO observatory on April 22 (UT) 18:54:58 - 19:55:14 under mean seeing of 2.8 arcsec and with Shajn telescope of CrAO observatory on April 23 (UT) 18:22:50 - 19:29:02 under mean seeing of 1.8 arcsec. In both epochs we cannot resolve the afterglow (Cucchiara et al., GCN 13245; Kuin et al., GCN 13248) from possible host galaxy SDSS J090738.51+140108.3 and we used aperture photometry of host + afterglow. A preliminary photometry is based on the USNO-B1.0 star 1040-0165213 (09 07 37.94 +14 00 43.0) assuming R=16.37: T0+ Filter, Exposure, OT+host, uplim (3 sigma) (mid, d) (s) 0.5091 R 20x180 20.5 +/-0.3 20.8 1.4891 R 60x60 20.74 +/-0.03 23.9 From the above photometry of the host + afterglow it is evident that in both epochs there is apparent admixture of the afterglow in the brightness of the galaxy SDSS J090738.51+140108.3 which have a brightness of R ~ 21.0. We are grateful for CCD PL4240 provided by ISON for Shajn telescope.
GCN 13275 table
GRB_name GRB120422A
GCN_number 13275
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13275 SUBJECT: GRB 120422A: i-band re-brightening and possible SN detection DATE: 12/04/30 23:33:38 GMT FROM: Giorgos Leloudas at Dark Cosmology Centre D. Malesani (DARK/NBI), S. Schulze (Univ. Iceland), T. Kruehler (DARK/NBI), G. Leloudas (OKC/Stockholm and DARK/NBI), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), D. Xu (WIS), J. P. U. Fynbo, J. Hjorth (DARK/NBI), P. Jakobsson (Univ. Iceland), R. Kotak, D. Wright (Queens University Belfast), G. Barisevicius, S. Geier (NOT), report on behalf of a larger collaboration: We have used the NOT equipped with ALFOSC to monitor the optical counterpart of GRB 120422A (Troja et al., GCN 13243; Cucchiara et al., GCN 13245). The source brightened by 0.80 +- 0.15 mag between Apr. 25.86 UT and Apr. 30.90 UT (3.56 and 8.60 days after the GRB, respectively). On Apr. 25.86 UT the counterpart had i ~ 22.10, calibrated against stars from the SDSS catalogue. This is consistent with the measurement by Perley et al. (GCN 13267) at a similar epoch. On Apr. 30.90 UT, we measure i = 21.30 +/- 0.15. We suggest this re-brightening to be due to the emerging supernova.
GCN 13276 table
GRB_name GRB120422A
GCN_number 13276
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13276 SUBJECT: GRB 120422A: Gemini-N detection of a supernova DATE: 12/05/01 14:30:04 GMT FROM: Nial Tanvir at U.Leicester K. Wiersema (U. Leicester), A. Cucchiara (UCSC/UCO Lick), A. J. Levan (U. Warwick), S. Rapoport, B. P. Schmidt (ANU), D. Bersier (LJMU), D. Perley (Caltech), S. B. Cenko (UC Berkeley), N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration: We observed the position of GRB 120422A (Troja et al., GCN 13243) using the GMOS-N Spectrograph on the Gemini-North telescope. We acquired spectra starting at 06:36 UT on 1 May 2012. We used the R400 grism, obtaining 4 x 1200 seconds exposure time, covering a wavelength range 4400 - 8670 A. In addition to many narrow nebular lines from the host galaxy (Tanvir et al. GCN 13251; Schulze et al. GCN 13257), the spectra show several broad undulations in the continuum. The restframe positions of these features are well matched to those seen in spectra of SN 1998bw at early times. We therefore conclude that the rebrightening reported by Malesani et al. (GCN 13275) is consistent with being caused by a broad-lined type Ib/c supernova. We thank Kristin Chiboucas for obtaining these observations.
GCN 13277 table
GRB_name GRB120422A
GCN_number 13277
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13277 SUBJECT: GRB 120422A: VLT/X-shooter spectroscopic evidence for a SN DATE: 12/05/01 14:30:06 GMT FROM: Bo Milvang-Jensen at Dark Cosmology Centre,NBI,U. Copenhagen D. Malesani (DARK/NBI), S. Schulze (Univ. Iceland), T. Kruehler, J. P. U. Fynbo, J. Hjorth, B. Milvang-Jensen, D. Watson (DARK/NBI), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), N. R. Tanvir (Univ. Leicester), G. Tagliaferri (INAF-OAB), G. Leloudas, J. Sollerman (OKC, Stockholm), D. Xu (WIS, Israel), M. D. Stritzinger (IFA, Aarhus), A. De Cia (Univ. Iceland) report on behalf of the X-shooter GRB GTO collaboration: We observed the re-brightened optical counterpart of GRB 120422A (Troja et al., GCN 13243; Cucchiara et al., GCN 13245; Malesani et al., GCN 13275) with the ESO VLT equipped with the X-shooter spectrograph. Observations started on 2012 May 1.0 UT (8.7 days after the GRB), for a total exposure time of 80 min in each of the UVB, VIS, and NIR arms, covering the wavelength range 3000-25000 A. The slit was aligned to cover both the galaxy at z = 0.28 present in the SDSS (Cucchiara et al., GCN 13245; Tanvir et al., GCN 13251) and the optical counterpart (Cucchiara et al., GCN 13245). The spectrum exibits a broad emission peak centred at 6300 A similar to the previous report based on a Keck spectrum taken on April 27 (Perley et al., GCN 13267). Blueward of the peak the spectrum drops steeply down to around 4000 A and beyond that we do not detect flux. Over the full covered spectral range the spectrum bears a good resemblance with spectra of SN 1998bw, associated with GRB 980425, about 6 days before maximum (Patat et al. 2001, ApJ, 555, 900). We acknowledge the excellent support of the ESO observing staff, in particular Claudio Melo, Giacomo Beccari, Marcelo Lopez and Ivo Saviane. We also thank the visiting astronomer Luca Sbordone for allowing us to observe the event.
GCN 13278 table
GRB_name GRB120422A
GCN_number 13278
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13278 SUBJECT: GRB 120422A: CARMA 3mm observations DATE: 12/05/03 02:58:42 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) reports on behalf of a larger collaboration: We observed the position of GRB 120422A (Troja et al., GCN 13243) with the Combined Array for Research in Millimeter-Wave Astronomy (CARMA) at a frequency of 92.5 GHz (3 mm) between 23:13 on 2012-04-24 and 00:29 on 2012-04-25 (UT). The mean observation time was 2.6937 days after the GRB trigger. No source is detected at the position of the X-ray (GCN 13243) optical (Cucchiara et al., GCN 13245) and radio (Zauderer et al., GCN 13254) counterparts. The 3-sigma limit of the map is 1.15 mJy.
GCN 13279 table
GRB_name GRB120422A
GCN_number 13279
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13279 SUBJECT: GRB 120422A: P200 NIR detection DATE: 12/05/03 03:21:57 GMT FROM: Daniel Perley at Caltech D. A. Perley, T. Jones, and R. Ellis (Caltech) report: We observed the field of GRB 120422A (Troja et al., GCN 13243) with the Wide-field IR Camera (WIRC) on the Palomar 200-inch telescope between 04:01 and 05:04 UT on 2012-05-02. 15 exposures of 240s each (1 hour of observations total) were acquired in the J-band filter. The optical counterpart to GRB 120422A (at this stage probably a rising supernova; GCNs 13275, 13276, 13277) is clearly detected in the combined image. Seeing conditions were good and the transient is resolved from its host galaxy, although the background is affected by scattered light from the bright star 1 arcmin to the northwest. Using a 0.8 arcsec radius aperture, we measure a magnitude of J = 20.7 +/- 0.2 at a mean time of 9.89 days after the burst.
GCN 13281 table
GRB_name GRB120422A
GCN_number 13281
Detection_method Optical
redshift 0.2830
Circular_text TITLE: GCN CIRCULAR NUMBER: 13281 SUBJECT: GRB 120422A: SN identification from GTC DATE: 12/05/07 18:55:42 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC R. Sanchez-Ramirez (IAA-CSIC), G. Leloudas (OKC, Stockholm), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), J. Gorosabel (IAA-CSIC), D. Malesani (DARK/NBI), S. Schulze (Univ. Iceland), J. P. U. Fynbo (DARK/NBI), N. R. Tanvir (Univ. Leicester), J. Hjorth (DARK/NBI), D. Xu (WIS) report on behalf of a larger collaboration: We have obtained spectroscopy of the optical counterpart of GRB 120422A (Troja et al. GCN 13243, Cucchiara et al. GCN 13245) and its host galaxy, at a redshift of 0.283 (Tanvir et al. GCN 13251, Schulze et al. GCN 13257) in two epochs, 3.6 and 14.6 days after the burst. Both spectra were obtained with a resolution of ~500 and cover the range between 4800 and 10000 AA. The first epoch is close to the minimum of the light curve, before the detection of the SN component (Malesani et al. GCN 13275), the spectrum is blue, flattening at ~5000 AA. It shows nebular emissions but no clear characteristic broad features of a SN spectrum. In the second spectrum, we clearly detect SN features, as reported by Wiersema (GCN 13276) and Malesani (GCN 13277). These features are now prominent and give an excellent match with those of broad-lined Ic SNe close to maximum, using SNID (Blondin & Tonry 2007, ApJ, 666, 1024). In our spectra we included an object located 5" East of the host galaxy, which has emission lines at the same redshift as the host and a projected distance at z=0.283 of 22 kpc. This could indicate the existence of an interacting system. We acknowledge the excellent support of the GTC staff, in particular Jose Miguel Gonzalez Perez, Daniel Reverte Paya, Antonio Cabrera Lavers and Rene Rutten.
GCN 13288 table
GRB_name GRB120422A
GCN_number 13288
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13288 SUBJECT: GRB 120422A: Konkoly optical observations DATE: 12/05/12 21:25:09 GMT FROM: Janos Kelemen at Konkoly Obs/Hungary J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program at the Konkoly Observatory. Starting on the evening of 11/05/2012 we observed the field of GRB 120422A (Troja et al., GCN 13243) 19.448 days after the burst, using a 50 cm Cassegrain telescope located at the Mountain Station of the Konkoly Observatory equipped with an Andor iXon + 888 EMCCD camera through R and I filters. On the coadded R images (exp.time 600 sec) we could not detect the OT associated SN (Giorgos Leloudas GCN 13275)and the nearby galaxy (SDSS J090738.51+140108.3)(A. Cucchiara GCN 13245). Based on a nearby star (USNO-A2.0 0975-06157109) we provide 19.07 +/- 0.26 magnitude in the R band as an upper limit.
GCN 18183 table
GRB_name GRB120422A
GCN_number 18183
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 18183 SUBJECT: KAIT Optical Upper Limits for GRB 120422A, 120724A, 120803B, 120911A, and 120923A DATE: 15/08/20 18:55:59 GMT FROM: Xiang-Gao Wang at GuangXi U Xianggao Wang (UC Berkeley, GXU, UNLV), WeiKang Zheng, Alexei V. Filippenko (UC Berkeley), and S. Bradley Cenko (GSFC) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRBs 120422A (Troja et al., GCN 13243), 120724A (D'Avanzo et al., GCN 13510), 120803B (Racusin et al. GCN 13566), 120911A (Cannizzo et al., GCN 13744), and 120923A (Yershov et al., GCN 13796) at 510 s, 202 s, 196 s, 147 s, and 236 s after the burst, respectively. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. We do not detect any new sources within the XRT error circles. We estimate the following upper limits (magnitudes) in clear-band images for each GRB calibrated to USNO B1.0: GRB Start-Time Coadd-Images Mid-time Upper-Limit (3 sigma) 120422A 510 s 20 s x 6 758 s 20.6 120724A 202 s 20 s x 10 647 s 20.7 120803B 196 s 20 s x 10 644 s 21.7 120911A 147 s 20 s x 6 501 s 20.9 120923A 236 s 20 s x 6 563 s 21.0