Gamma-ray Burst 130606B
(All information courtesy of the instrument teams.)
Previous IAU Circulars
Results of Observations
- GCN Circular #14795
G. Vianello (Stanford University), J. Racusin (NASA/GSFC), Nicola Omodei
(Stanford University) and M. Ohno (Hiroshima U.) report on behalf of the
At 11:55:33 UT on 06 June 2013, Fermi LAT detected high energy emission
from GRB 130606B, which was also detected by Fermi-GBM (trigger 392212536 /
130606497). The brightness of the event in GBM triggered an autonomous
repoint of the spacecraft. Unfortunately, the GBM flight software
determined an unreliable position and the spacecraft slewed to that
We were nevertheless able to detect a very clear excess at the position:
(RA, Dec) = 218.574, -22.131 (J2000) with an error radius of 0.1 deg (68%
containment radius, statistical errors only)
which was within the LAT field of view between T0 + 180 s and T0 + 1000 s.
Using SOURCE class we detected > 10 events, with 4 events above 1 GeV,
compatible with the position of the source during this time interval.
This source was about 91 deg from the LAT boresight at the time of the
trigger and during the whole prompt emission (~100 s long), well outside
the nominal field of view for the standard data analysis. However, we
detected a strong signal using the non-standard LLE selection, most
sensitive in the 10 MeV - 100 MeV energy range and featuring a broader
acceptance. We detected an excess of more than 17 sigma in a time interval
from 5 to 30 s after the trigger, composed of few hundreds events above the
background level. The effective area of the LLE class is small at such high
off-axis angle, therefore the strong excess indicates that this burst was
exceptionally bright and hard.
A Swift TOO request has been submitted.
A GBM circular is forthcoming.
The Fermi LAT point of contact for this burst is Giacomo Vianello (
The Fermi LAT is a pair conversion telescope designed to cover the energy
band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
- GCN Circular #14801
Subject: GRB 130606B: Fermi GBM observation
Hoi-Fung Yu (MPE)
reports on behalf of the Fermi GBM Team:
"At 11:55:33.63 UT on 6 June 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130606B (trigger 392212536 / 130606497).
The GBM on-ground location is consistent with the LAT position
(Vianello et al., GCN 14795). The angle from the Fermi LAT boresight
is 93 degrees.
The high peak flux from the GRB caused GBM to issue an autonomous
rapid repoint (ARR) maneuver but to an unreliable sky position
according to the flight software calculation.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve shows a multi-peaked feature with a duration (T90)
of about 52 s (50-300 keV). The time-averaged spectrum from T0+0.003 s
to T0+65.537 s is well fit by a Band function with
Epeak = 435 +/- 11 keV, alpha = -1.14 +/- 0.01, and
beta = -2.05 +/- 0.02.
The event fluence (10-1000 keV) in this time interval is
(2.034 +/- 0.007)E-04 erg/cm^2. The 1.024 s peak photon flux measured
starting from T0+9.15 s in the 10-1000 keV band
is 62.14 +/- 0.58 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #14803
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long-duration intense hard-spectrum GRB 130606B
(Fermi-LAT detection: Vianello et al., GCN 14795;
Fermi-GBM detection: Yu, GCN 14801)
triggered Konus-Wind at T0=3D42940.544s UT (11:55:40.544).
The light curve shows a bright hard pulse complex from ~T0 to ~T0+70 s,
followed by a weak soft tail of emission out to ~T0+100s.
The emission at the main phase is seen up to ~17 MeV.
The Konus-Wind light curve of this GRB is available at
Periodic `dips' visible in the 64-ms light curve are
due to the source occultation by the spacecraft.
As observed by Konus-Wind, the burst
had a fluence of (4.3 =B1 0.1)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+8.064s,
of (5.7 =B1 0.3)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+67.328 s)
is best fit in the 100 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha =3D -1.25 =B1 0.15,
the high energy photon index beta =3D -1.92 =B1 0.02,
the peak energy Ep =3D 337 =B1 59 keV,
chi2 =3D 120/81 dof.
The spectrum at the maximum count rate
(measured from T0+7.680 to T0+8.704 s)
is best fit in the 50 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha =3D -0.92 =B1 0.18,
the high energy photon index beta =3D -1.87 =B1 0.10,
the peak energy Ep =3D 690 =B1 240 keV,
chi2 =3D 96/90 dof.
All the quoted results are preliminary.
- GCN Circular #14820
J. A. Kennea (PSU) reports on behalf of the Swift-XRT team:
We have analysed 3.1 ks of XRT data for the Fermi/LAT-detected burst:
GRB 130606B, from 106.6 ks to 114.1 ks after the Fermi/LAT trigger.
The data are entirely in Photon Counting (PC) mode. An X-ray source is
detected within the Fermi/LAT error circle. Using 2899 s of PC mode
data and 4 UVOT images, we find an enhanced XRT position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 218.52931, -22.10229 which is equivalent to:
RA (J2000): 14h 34m 07.04s
Dec(J2000): -22d 06' 08.2"
with an uncertainty of 1.8 arcsec (radius, 90% confidence). This
position is 181 arcsec from the Fermi/LAT position. the light curve is
consistent with a constant source of mean count rate 8.0e-02 ct/sec.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.3 (+/-0.4). The
best-fitting absorption column is 2.0 (+1.0, -0.9) x 10^21 cm^-2, in
excess of the Galactic value of 6.7 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 3.3 x 10^-11 (5.6 x 10^-11) erg
A summary of the PC-mode spectrum is thus:
Total column: 2.0 (+1.0, -0.9) x 10^21 cm^-2
Galactic foreground: 6.7 x 10^20 cm^-2
Excess significance: 2.5 sigma
Photon index: 2.3 (+/-0.4)
The results of the XRT-team automatic analysis are available at
This circular is an official product of the Swift-XRT team.
- GCN Circular #14822
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC),
William 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), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels=
and Harvey Moseley (GSFC) report:
We observed the field of GRB 130606B (Vianello et al., GCN Circular
14795) 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 2013/06 7.16 to
2013/06 7.25 UTC (15.97 to 18.08 hours after the BAT trigger), obtaining
a total of 0.36 hours exposure in the r' and i' bands and 0.30 hours
exposure in the Y and H bands.
For a source within the XRT error circle (Kennea et al., GCN Circular
14820), in comparison with USNO-B1 and 2MASS, we obtain the following
3-sigma upper limits:
r' > 23.59
i' > 23.61
Y > 21.52
H > 20.73
These magnitudes are in the AB system and not corrected for Galactic
extinction in the direction of the GRB.
No further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr=
- GCN Circular #14823
M. Marisaldi, F. Fuschino (INAF/IASF-Bo), F. Verrecchia, C. Pittori (ASDC and INAF/OAR), A. Giuliani (INAF/IASF-Mi), F. Longo (University of Trieste and INFN Trieste), F. Lucarelli (ASDC and INAF/OAR), E. Del Monte, F. Lazzarotto, I. Donnarumma, Y. Evangelista, M. Feroci, L. Pacciani, P. Soffitta, E. Costa, I. Lapshov, M. Rapisarda (INAF/IAPS Rome), G. Barbiellini, (INFN Trieste), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, V. Fioretti, M. Galli (INAF/IASF-Bo), A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF-Mi), M. Cardillo, E. Striani, M. Tavani (INAF/IAPS Rome, and Univ. Roma Tor Vergata), A. Argan, G. Piano, S.
Sabatini, V. Vittorini (INAF/IAPS Rome), G. Pucella (ENEA Frascati), A. Pellizzoni, A. Trois (INAF/OA Cagliari), M. Pilia (ASTRON), S. Vercellone (INAF/IASF-Pa), P. W. Cattaneo, A. Rappoldi (INFN Pavia), A. Morselli, P. Picozza (INFN Roma-2), M. Prest, E. Vallazza (Universita`
dell'Insubria), S. Colafrancesco (INAF/OAR and WITS), P. Lipari, D. Zanello (INFN Roma-1), P. Giommi (ASI), and G. Valentini (ASI),
on behalf of the AGILE Team, report:
"The long hard bright GRB 130606B, observed in gamma-rays by Fermi-LAT (Vianello et al., GCN 14795), Fermi-GBM (Yu et al., GCN 14801) and Konus-Wind (Golenetskii et al., GCN 14803), triggered AGILE-MCAL, sensitive in the range 0.4 - 100 MeV, at 11:55:33 UT (T0).
The light curve above 400 keV shows three main peaks between T0 and T0 + 20 s, followed by two less bright peaks at T0 + 40 s and T0 + 50 s.
The time-integrated spectrum measured between T0 and T0 + 20 s can be fit in the energy range 0.5 - 20 MeV with a simple power law with photon index -2.15 +/- 0.03 and reduced chi-squared 1.67 (46 d.o.f). As observed by MCAL the burst fluence in the same energy range and time interval is (1.62 +/- 0.05)E-04 erg/cm^2. All quoted errors are at 90% confidence levels.
The burst was 118 degrees off-axis with respect to the AGILE GRID pointing direction at T0, from a sky region not accessible to the GRID.
This measurement was obtained with AGILE observing a large portion of the sky in spinning mode."
- GCN Circular #14855
C. A. Swenson (PSU) and D. Kocevski (NASA/GSFC/ORAU) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of
GRB 130606B 106.6 ks after the Fermi/LAT trigger (Vianello
et al., GCN 14795). No optical afterglow consistent with
the position of the potential X-ray candidate (Kennea, GCN
14820) is detected in the UVOT exposures. A preliminary 3-
sigma upper limit using the UVOT photometric system (Breveld
et al., 2011, AIP Conf. Proc. 1358, 373) for the initial
Filter T_start(s) T_stop(s) Exp(s) Mag
------ ---------- --------- ------ ---
White 106556 123017 4142 >22.6
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.10 in the
direction of the burst (Schlegel et al. 1998)
- GCN Circular #14892
Y. Ishida, M. Tashiro, Y. Terada, T. Yasuda, H. Ueno, S. Sugimoto
(Saitama U.), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui,
Y. Fukazawa (Hiroshima U.), M. Yamauchi, N. Ohmori, M. Akiyama
(Univ. of Miyazaki), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.),
Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri
(RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa,
K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team,
The bright, long GRB 130606B (Fermi-LAT detection: G. Vianello, et al .
14795) triggered the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at UT 11:55:35.360(=T0).
The observed light curve shows a multi-peaked structure starting at
T0-3.5 s, ending at T0+63 s with a duration (T90) of about 43.7 seconds.
The fluence in 100 - 1000 keV was 1.33 (-0.73, +0.02) *10^-4 erg/cm^2.
The 1-s peak flux measured from T0+11.5 s was
20.64 (-4.72, +0.51) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-3 s to
T0+63 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -1.24 (-0.31, +0.79),
the high-energy photon index beta: -2.08 (-0.16, +0.11),
and the peak energy Epeak: 619 (-251, +396) keV,
(chi^2/d.o.f = 17.1/13).
Due to the brightness of this burst, a 3% systematic error was added for
low energy channels.
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst are available at:
- 1501.0508 from 22 Jan 15
Yunguo Jiang et al.: GRB Spectra in the complex of synchrotron and Compton processes
Under the steady state condition, the spectrum of electrons is investigated by solving the continuity equation under the complex radiation of
both the synchrotron and Compton processes. The resulted GRB spectrum is a broken power law in both the fast and slow cooling phases. On the
basis of this electron spectrum, the spectral indices of the Band function in four different phases are presented. In the complex radiation
frame, the detail investigation on physical parameters reveals that both the reverse shock photosphere model and the forward shock with strong
coupling model can answer the $\alpha \sim -1$ problem. A possible marginal to fast cooling phase transition in GRB 080916C is discussed. The
time resolved spectra in different pulses of GRB 100724B, GRB 100826A and GRB 130606B are investigated. We found that the flux is proportional
to the peak energy in almost all pulses. The phases for different pulses are determined according to the spectral index revolution. We found
the strong correlations between spectral indices and the peak energy in GRB 100826A, which can be explained by the Compton effect in the fast
cooling phase. However, the complex scenario predicts a steeper index for the injected electrons, which challenges the acceleration mechanism
- 1505.05858 from 22 May 15
Bin-Bin Zhang et al.: Synchrotron Origin of the Typical GRB Band Function - A Case Study of GRB 130606B
We perform a time-resolved spectral analysis of GRB 130606B within the framework of a fast-cooling synchrotron radiation model with magnetic
field strength in the emission region decaying with time, as proposed by Uhm & Zhang. The data from all time intervals can be successfully fit
by the model. The same data can be equally well fit by the empirical Band function with typical parameter values. Our results, which involve
only minimal physical assumptions, offer one natural solution to the origin of the observed GRB spectra and imply that, at least some, if not
all, Band-like GRB spectra with typical Band parameter values can indeed be explained by synchrotron radiation.
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