Gamma-ray Burst 130305A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #14257
  J. R. Cummings (NASA/GSFC UMBC/CRESST) and D. M. Palmer (LANL) report on behalf of the Swift/BAT team:
  At 11:39:16, BAT triggered on GRB 130305A (trigger #550329). No source was found on board. This burst was also detected by Fermi (trignum=384176354) and INTEGRAL (TRIGGER_NUM: 6794, Sub_Num: 0). In ground analysis of the BAT scaled-map data, a significant source was found on the edge of the BAT FOV (2.25% coded) at RA, Dec 116.765, +52.025, which is:

  RA (J2000)  07h 47m 03.6s 	
  Dec (J2000) 52d 01m 29s
  

  with an estimated 90% uncertainty radius of 3.5 arcmin.
  The GRB was a single symmetrical peak about 20 seconds long. A Swift TOO request has been approved to detect the afterglow position.
• GCN Circular #14260
  S. Guiriec (NASA/GSFC/NPP), J. L. Racusin (NASA/GSFC), G. Vianello (Stanford) and D. Kocevski (NASA/GSFC/NPP) report on behalf of the Fermi-LAT team:
  The Fermi Large Area Telescope (LAT) detected emission from GRB 130305A at approximately 11:39:11 UT on March 5th, 2013, while in Target Of Opportunity (i.e., pointing) mode observing the Crab (ATEL #4855). GRB 130305A was detected by Fermi-GBM (GBM trigger 130305486/384176354) and Swift-BAT (Cummings et al., GCN #14257).
  The burst location was within the LAT field of view at an angle of ~41 degrees to the LAT boresight, and ~100 degrees from the zenith, placing it very close to the Earth's limb, which is a very bright source of gamma rays. No significant excess is seen using standard analysis procedures (>100 MeV) neither in the prompt phase nor in a search for extended emission when the burst position was no longer occulted from ~1500 to 5000 s.
  Using the non-standard LAT Low Energy (LLE) data selection, >550 counts above background were detected in a single FRED like pulse, peaking between 5 and 10 s after the GBM trigger and coinciding with the time of the GBM emission, with a significance of ~10.7 sigma. This detection is due to low energy gamma-rays, below 75 MeV, and therefore has insufficient spatial resolution to provide a reliable LAT localization.
  A GBM circular on GRB 130305A is forthcoming.
  The Fermi LAT point of contact for this burst is Sylvain Guiriec (sylvain.guiriec@nasa.gov)
• GCN Circular #14261
  Hoi-Fung Yu (MPE) and Shaolin Xiong (UAH) report on behalf of the Fermi GBM Team:
  "At 11:39:11.37 UT on 05 March 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130305A (trigger 384176354 / 130305486), which was also detected by the Fermi/LAT (S. Guiriec et al., GCN 14260) and the Swift/BAT (Cummings et al., GCN 14257). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is about 44 degrees.
  This burst was also independently detected by INTEGRAL SPI-ACS.
  The GBM light curve shows single pulse with a tail with a duration (T90) of about 29 s (50-300 keV). The time-averaged spectrum from T0-0 s to T0+30 s is best fit by a Band function with Epeak = 640 +/- 23 keV, alpha = -0.67 +/- 0.02, and beta = -2.4 +/- 0.1.
  The event fluence (10-1000 keV) in this time interval is (5.7 +/- 0.07)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+5.2 s in the 10-1000 keV band is 25.4 +/- 0.3 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #14262
  S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration intense GRB 130305A (Swift-BAT trigger #550329: Cumings & Palmer, GCN 14257; Fermi-LAT detection: Guiriec et al., GCN 14260; Fermi-GBM observation: Yu and Xiong, GCN 14261) triggered Konus-Wind at T0=3D41953.135s UT (11:39:13.135)
  The light curve shows a bright hard pulse with a total duration of ~30 s followed by a weaker hard emission tail out to ~T0+250 s. The emission in the main bursting episode is seen up to 12 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130305_T41953/
  As observed by Konus-Wind, the main pulse had a fluence of (8.5 =B1 0.6)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+4.480 s, of (1.6 =B1 0.1)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-integrated spectrum (measured from T0 to T0+36.096 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.81 =B1 0.04, the high energy photon index beta =3D -2.5 =B1 0.2, the peak energy Ep =3D 640 =B1 45 keV, chi2 =3D 83.7/95 dof.
  The spectrum at the maximum count rate (measured from T0 to T0+11.520 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.72 =B1 0.04, the high energy photon index beta =3D -2.8 =B1 0.2, the peak energy Ep =3D 655 =B1 30 keV, chi2 =3D 89.5/96 dof.
  The spectrum of the emission tail (measured from T0+36.096 to T0+224.512 = s) is best fit in the 20 keV - 10 MeV range by the simple power-law model with a rather hard photon index of (-1.4 =B1 0.1), chi2 =3D 71.7/89 dof. The emission in this time interval is seen up to 9 MeV and the 20 keV - 10 MeV energy fluence is (3.3 =B1 1.1)x10-5 erg/cm2.
  All the quoted results are preliminary.
• GCN Circular #14263
  Daniele Malesani (DARK/NBI), Bin-Bin Zhang (PSU), David N. Burrows (PSU), Dirk Grupe (PSU), report on behalf of the Swift-XRT team:
  The Swift spacecraft observed the ground-discovered BAT GRB 130305A (Cummings & Palmer, GCN 14257), also detected by Fermi GBM and LAT (Yu & Xiong, GCN 14261; Guiriec et al., GCN 14260), Konus/Wind (Golenetskii et al., GCN 14262) and INTEGRAL SPI-ACS.
  We have analysed 1.8 ks of XRT data, from 31.0 ks to 47.2 ks after the Swift/BAT trigger. The data are entirely in photon counting (PC) mode. An X-ray source is detected within the Swift/BAT error circle. The XRT position is RA, Dec = 116.74762, +52.03332 which is equivalent to:

  RA (J2000) = 07 46 59.43
  Dec(J2000) = +52 01 60.0
  

  with an uncertainty of 3.8 arcsec (radius, 90% confidence). This position is 49 arcsec from the Swift/BAT position.
  A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+0.7, -0.6). The best-fitting absorption column is 4.1 (+3.6, -2.5) x 10^21 cm^-2, in excess of the Galactic value of 4.8 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 4.3 x 10^-11 (7.3 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:         4.1 (+3.6, -2.5) x 10^21 cm^-2
  Galactic foreground: 4.8 x 10^20 cm^-2
  Excess significance: 2.4 sigma
  Photon index:         2.0 (+0.7, -0.6)
  

  Further observations by Swift are ongoing. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020234.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #14265
  S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:
  We imaged the location of the Swift (Cummings et al., GCN 14257), Fermi (Guiriec et al., GCN 14260; Yu et al., GCN 14261), and Konus (Golenetskii et al., GCN 14262) GRB 130305A with the robotic Palomar 60 inch telescope. Observations were obtained in the g', r', and i' filters beginning at 2:47 UT on 2013 Mar 6 (~ 15.1 hr after the Swift-BAT trigger).
  We do not detect any sources within the Swift-XRT error circle (Malesani et al., GCN 14263) in any filter. Using nearby point sources from SDSS for reference, we calculate limiting magnitudes of g' > 22.8, r' > 22.2, and i' > 21.7 at this time.
• GCN Circular #14267
  Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UN= AM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1= iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
  We observed the field of GRB 130305A (Cummings, et al., GCN 14257) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2013/03 6.12 to 2013/03 6.13 UTC (15.11 to 15.50 hours after the BAT trigger), obtaining a total of 0.31 hours exposure in the r' and i' bands.
  For a source within the Swift-XRT error circle (Malesani, et al., GCN 14263), in comparison with USNO-B1, we derive the following upper limits (3-sigma) in the AB magnitude system:

    r'  > 23.4
    i'  > 23.1
  

  These magnitudes are not corrected for Galactic extinction in the direction of the GRB.
  We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
• GCN Circular #14268
  A. A. Breeveld (MSSL-UCL), Daniele Malesani (DARK/NBI), Bin-Bin Zhang (PSU), S. R. Oates (MSSL-UCL) and M. De Pasquale (MSSL-UCL) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 130305A 30975s after the BAT trigger discovered in ground analysis (Cummings et al., GCN Circ. 14257). No optical afterglow consistent with the XRT position (Malesani et al., GCN Circ. 14263) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limit using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
  Filter T_start(s) T_stop(s) Exp(s) Mag
  u 30975 59030 3890 >21.4
  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #14272
  A. Cucchiara (UCSC/UCO Lick Observatory), S. B. Cenko (UC Berkeley), D. Perley (Caltech) report on behalf of a large collaboration:
  "On March 7.21 UT we observed the field of GRB 130305A (Cummings & Palmer, GCN 14257; Yu & Xiong, GCN 14261; Guiriec et al., GCN 14260) with the Gemini-North telescope equipped with the GMOS camera.
  We obtained 14x180s exposures, for a total integration time of 42 minutes (T_mid = T0+1.70 days). No clear object is detected within the XRT error circle down to r' > 26.1 mag.
  Nevertheless we note the presence of several galaxies just outside the current XRT error circle (2.7 arcsec radius), in particular of a relatively bright object in the S-W direction, which seems to show a distorted morphology (https://www.dropbox.com/s/pyir6g8mqd658xn/GRB130305A.jpeg). The galaxy coordinates are

  RA: 07:46:58.9  (J2000)
  Dec: +52:01:55.72 (J2000)
  

  We thank the Gemini staff for performing this observations, in particular J. Rhee."
  
• GCN Circular #14274
  Brajesh Kumar and S. B. Pandey (ARIES Nainital India, on behalf of larger Indian GRB collaboration).
  We observed the LAT detected GRB 130305A error-box (Cummings & Palmer GCN 14257; Guiriec et al. GCN 14260; Yu & Xiong GCN 14261) using 1.04m telescope at ARIES Nainital on 2013:03:05, 18:28:30 UT, ~6.8 hours after the Swift/BAT detection.
  Four frames in R_c pass-band 300sec each were acquired in good sky conditions. In the co-added image (4x300 sec), we did not detect any optical transient within the XRT error circle (Malesani et al. GCN 14263) down to a limiting magnitude of 21 mag. The photometry was performed in comparison to nearby USNO- B1 stars.
  This massage could be cited.
• GCN Circular #14276
  Bin-Bin Zhang (PSU), Daniele Malesani (DARK/NBI), Dirk Grupe (PSU), David N. Burrows (PSU) and Kim L. Page (U. Leicester) report on behalf of the Swift-XRT team:
  We have analyzed 16 ks of XRT data for the Swift/BAT-detected burst: GRB 130305A, from 31.0 ks to 210.2 ks after the Swift/BAT trigger. The data are entirely in Photon Counting (PC) mode. We confirm that the X-ray source reported in Malesani et al. GCN 1426 is fading. The light curve can be modeled with a power-law decay with a decay index of alpha=2.4 (+0.5, -0.4).
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020234.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #14277
  J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), D. Malesani (DARK/NBI), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
  Using 11 seconds of event data covering part of the burst, we present further analysis of GRB 130305A (Cummings and Palmer, GCN # 14257). This was a ground-detected burst on the edge of the BAT field of view. The best BAT position is RA, Dec 116.774, +52.037, which is:

  RA (J2000)   07h 47m 05.8s
  Dec (J2000)  52d 02m 11s
  

  with an estimated uncertainty radius of 1.8 arcmin (90% containment). This position is 1.0 arcmin from the XRT afterglow position (Malesani et al, GCN # 14263).
  The BAT mask-weighted lightcurve does not show more detail than the raw lightcurve due to the extreme partial coding (2.5%). There is a single peak, approximately symmetrical, a total of about 20 seconds long. Note, however, the much longer duration mentioned at high energy by the Konus-Wind team (Golenetskii et al., GCN # 14262.
  The following spectral results appear to cover about 90% of the total flux of the burst, based on the raw lightcurve excess over constant background. Again, the partial coding makes the uncertainty of the fit parameters large. A fit to a simple power law function has a photon index of 0.78 +/- 0.20. This is harder than most other BAT-detected long GRBs. The fluence from 15-150 keV was (4.8 +/- 1.8) x 10^-6 ergs/cm^2.
• GCN Circular #14309
  B. Stecklum, D. A. Kann and C. Hoegner (TLS Tautenburg) report:
  Following the announcement of the ground-detection of the bright GRB 130305A by Swift BAT (Cummings & Palmer 2013, GCN 14257), which was also detected by Fermi LAT (Guiriec et al. 2013, GCN 14260), Fermi GBM (Yu & Xiong 2013, GCN 14261) and Konus-Wind (Golenetskii et al. 2013, GCN 14262), we initiated observations with the 1.34m Schmidt telescope of the Thueringer Landessternwarte Tautenburg under excellent weather conditions at 18:11 UT, 22 minutes after the GCN notice.
  We obtained 6 x 600 sec exposures in the Rc band, centered 0.29299 days after the GRB. At the position of the XRT afterglow (Malesani et al. 2013, GCN 14263, Zhang et al. 2013, GCN 14276), we detect no source down to a 2 sigma upper limit of Rc > 23.2. Photometric calibration was obtained with respect to several SDSS stars in the field, using the transformations of Lupton (2005).
  This upper limit is deeper than the one obtained by Kumar & Pandey (2013, GCN 14274) at a similar time and earlier than several other reported observations (Cenko 2013, GCN 14265; Butler et al. 2013, GCN 14267; Breeveld et al. 2013, GCN 14268). We detect all the surrounding sources seen in the deep Gemini image (Cucchiara et al. 2013, GCN 14272).
  A second observation was attempted a day later, but due to inclement weather conditions only a single 600 sec image could be successfully obtained. It is significantly shallower than the stack of the first night and shows no changes.
  This message may be cited.
• GCN Circular #14313
  L. P. Singer (Caltech), S. B. Cenko (UC Berkeley), and D. A. Brown (Syracuse) report on behalf of a larger collaboration:
  We have imaged the 3-sigma Swift XRT error circle (D. Malesani, GCN 14263) of GRB130305A (Fermi384176354, J. R. Cummings, GCN 14257) with the Palomar 48 inch Oschin telescope (P48) as part of the Palomar Transient Factory (PTF). Images were obtained in the Mould R filter at 2013-03-06 at 05:13:35 and 05:56:17 UTC, 17.6 and 18.3 hours after the trigger.
  We find no point source, fading or otherwise, to 5-sigma limiting magnitudes of 20.8 and 20.8.
• GCN Circular #14324
  A.Volnova (SAI MSU/IKI), R. Burenin(IKI), E. Klunko (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
  We observed We imaged the location of the Swift (Cummings et al., GCN 14257), Fermi (Guiriec et al., GCN 14260; Yu et al., GCN 14261), and Konus (Golenetskii et al., GCN 14262) GRB 130305A with AZT-33IK telescope of Sayan observatory (Mondy) on March 05 between (UT) 20:44:08 - 22:17:04. We took several images in R-filter of 100 s exposure under unfavorable seeing (FWHM) of about 4.2 arcsec. We do not detect any sources within the XRT error circle (Malesani et al., GCN 14263). A photometry of a combined image is following

  UT start,  t-t0       Filter Exp.   OT    UL (3 sigma)
             (mid, days)        (s)
  
  20:44:08  0.41071     R      35x100 n/d   21.4
  

  The photometry is based on SDSS DR8 star SDSS J074702.42+520103.3 07:47:02.43 +52:01:03.4 R = 16.94
• GCN Circular #14326
  A. Cucchiara (UCSC/UCO Lick Observatory), S. B. Cenko (UC Berkeley), D. Perley (Caltech) report on behalf of a large collaboration:
  "On March 20.31 UT we observed again the field of GRB 130305A (Cummings & Palmer, GCN 14257; Yu & Xiong, GCN 14261; Guiriec et al., GCN 14260) with the Gemini-North telescope equipped with the GMOS camera.
  We obtained 7x180s exposures, for a total integration time of 21 minutes (T_mid = T0+13.10 days).
  We compared the coadded image with our pervious observation (Cucchiara et al. GCN 14272) and performed an image subtraction between the two epochs.
  No variable source appears in the subtraction image, in particular we note that the galaxy reported in GCN 14272 appears of constant brightness.
  We estimated a limiting magnitude of r' > 26.0 within the XRT circle.
  We thank the Gemini staff for performing this observation.
• GCN Report 436.1
  GCN_Report 436.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_436_1.pdf by D. Malensani at DARK/NBI titled: "Swift Observations of GRB 130305A"