GRB 130722A

Owen Littlejohns (ASU), 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), Enrico Ramirez-Ruiz
(UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González
(UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley
(GSFC) report:

We observed the field of GRB 130722A (Melandri, et al., GCN 15013
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 ) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2013/07 23.23 to 2013/07 23.39 UTC (21.24 to
25.00 hours after the BAT trigger), obtaining a total of 2.33 hours
exposure in the i' band.

We detect the candidate GRB host galaxy from Melandri et al. (GCN 15015
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 )
noting also that the source is extended. In comparison with USNO-B1, we
obtain:

 i'     19.58 +/- 0.02

This magnitude is in the AB system and not corrected for Galactic
extinction in the direction of the GRB.  We do not detect the candidate OT,
although it is likely blended with the host galaxy. In comparison with the
Faulkes measurement one night earlier, the OT has thus faded by at least
1.5 magnitudes.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.

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 GRB 130722A
(Swift-BAT trigger 563213: Troja, et al., GCN 15013
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 )
triggered Konus-Wind at T0=30001.378 s UT (08:20:01.378).

The light curve  from ~T0-6 s to ~T0+55 s shows two main
emission pulses peaked at ~T0+1 s and ~T0+31 s, respectively.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130722_T30001/

As observed by Konus-Wind, the burst
had a fluence of (2.35 � 0.12)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.256s,
of (1.84 � 0.22)x10-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The 3-channel time-integrated spectrum
(measured from T0-6.663 to T0+55.191 s)
can be modeled, in the 20 keV - 1.35 MeV range,
by cutoff power law with the following model parameters:
the photon index alpha = -0.92 � 0.03
and the peak energy Ep = 179 � 5 keV,

The spectrum at the maximum count rate
(measured from T0 to T0+8.448 s)
is best fit, in the 20 keV - 5 MeV range,
by cutoff power law with the following model parameters:
the photon index alpha = -0.76 � 0.12
and the peak energy Ep = 219 � 15 keV,
chi2 = 90.3/76 d.o.f.

All the quoted results are preliminary.

F. E. Marshall (NASA/GSFC) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130722A
120 s after the BAT trigger (Troja et al., GCN Circ. 15013
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 ).
A decaying source consistent with the optical position
(Melandri et al. GCN Circ. 15015
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 )
is detected in the initial UVOT exposures.
As noted by Melandri et al., there is a catalogued source
near the position of the optical afterglow.
The magnitudes and uncertainties reported below have been
adjusted to accommodate the possibility that the nearby
source accounts for all or none of the UVOT count rate
observed at late times.

The preliminary UVOT position is:
  RA(J2000)  =  17:22:36.47 = 260.65196
  DEC(J2000) = -02:58:21.6  =  -2.97268
with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence).
The uncertainty has been adjusted slightly due to the
possible contamination of the nearby source by up to 10%.

The preliminary detection 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           120          270          147          19.6 (+0.12/-0.20)
v                 4209         5844          393         >19.7
b                 3594        17728         2039         >20.9
u                  332        16943         2059         >21.0
w1                4619        16030         1218         >21.2
w2                4004         5640          393         >21.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.63 in the direction of the burst
(Schlegel et al. 1998).

D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of MITSuME collaboration:

We observed the field of GRB 130722A (Troja et al., GCNC 15013)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.

The observation started on 2013-07-22 11:15:06 UT (~2.9 h after the burst).
We could not detect the previously reported afterglow
(Melandri et al., GCNC 15015; Trotter et al., GCNC 15017) in all the three bands.

Three sigma upper limits of the OT are listed below.
We used GSC 2.3 catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.23056    13:51:20    9000.0   >18.7  >18.8  >18.3
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 6812 s of XRT Photon Counting mode data and 11 UVOT
images for GRB 130722A, 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 = 260.65190, -2.97283 which is equivalent
to:

RA (J2000): 17h 22m 36.46s
Dec (J2000): -02d 58' 22.2"

with an uncertainty of 1.4 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.

D.N. Burrows (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAB), B.
Sbarufatti (INAF-OAB/PSU), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU),
V. Mangano (PSU) and E. Troja report on behalf of the Swift-XRT team:

We have analysed 7.3 ks of XRT data for GRB 130722A (Troja  et al. GCN
Circ. 15013
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 ),  from 117 s to 17.7 ks after the	BAT trigger. The data
comprise 739 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The refined XRT position is RA, Dec =
260.65405, -2.97376 which is equivalent to:

RA (J2000): 17 22 36.97
Dec(J2000): -02 58 25.5

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The late-time light curve (from T0+3.6 ks) can be modelled with  a
power-law decay with a decay index of alpha=1.10 (+/-0.11).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.21 (+/-0.05). The
best-fitting absorption column is  4.18 (+0.18, -0.17) x 10^21 cm^-2,
in excess of the Galactic value of 1.2 x 10^21 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 1.89 (+0.16, -0.15)
and a best-fitting absorption column of 4.9 (+0.9, -0.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.8 x 10^-11 (7.8 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     4.9 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^21 cm^-2
Excess significance: 7.3 sigma
Photon index:	     1.89 (+0.16, -0.15)

If the light curve continues to decay with a power-law decay index of
1.10, the count rate at T+24 hours will be 0.023 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.8 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00563213.

This circular is an official product of the Swift-XRT team.

A. Trotter, D. Reichart, K. McLin, L. Cominsky, T. Berger, M. Carroll, 
H. T. Cromartie, R. Egger, A. Foster, C. Foster, N. Frank, J. Haislip, 
K. Ivarsen, D. James, A. LaCluyze, M. Maples, J. Moore, M. Nysewander, 
E. Speckhard, P. Taylor, and J. A. Crain report:

Skynet observed the Swift/BAT localization of GRB 130722A (Troja et al., 
GCN 15013
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 , Swift trigger 563213) in the Rc and Ic bands with the 14" 
GLAST Optical Robotic Telescope (GORT) at the Hume observatory in 
California, beginning at t=100s post trigger and continuing until t~1hr. 
In stacked exposures, we marginally detect a source in both bands at the 
afterglow position reported by Melandri et al. (GCN 15015
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 ). Photometry 
is calibrated to 3 USNO-B1 stars in the field:

band     t[min]     exp[min]     mag
Rc       38         31           18.6 (+0.4, -0.3)
Ic       41         35           17.6 (+0.3, -0.2)

No further Skynet observations are scheduled.

A. Melandri (INAF/OAB), C. Guidorzi (U. Ferrara), J. Japelj (U.  
Ljubljana), D. Kopac (U. Ljubljana), C.G. Mundell (LJMU) and A. Gomboc  
(U. Ljubljana) report:

The 2-m Faulkes Telescope South automatically began observing GRB  
130722A (Troja et al. GCN Circ. 15013
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 ) on July 22 2013 at 08:21:29 UT  
(~130 s after the burst trigger).

We find a fading object at coordinates

RA(2000.0)=   17:22:36.47
Dec(2000.0)= -02:58:21.6   (error 1.3")

with the following magnitudes

Mid time from  Total Exp   Filter    Magnitude
trigger (min)   (s)
--------------------------------------------------------------
12.37           1x30        R       18.0 +- 0.1
18.07           1x60        R       18.3 +- 0.1
--------------------------------------------------------------

Magnitudes are calibrated against nearby USNO-B1 stars, performing  
aperture photometry of the proposed optical counterpart above together  
with the nearby object located at RA(2000.0)=17:22:36.54,  
Dec(2000.0)=-02:58:22.1. The latter might be related to the OT, has a  
distance of 1.2" from the candidate and a catalogued magnitude of  
R2=19.7. It looks extended and might be the host galaxy of GRB 130722A.

E. Troja (NASA/GSFC/UMCP), V. D'Elia (ASDC),
C. J. Mountford (U Leicester), C. Pagani (U Leicester),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:

At 08:19:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130722A (trigger=563213).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 260.670, -2.979 which is 
   RA(J2000) = 17h 22m 41s
   Dec(J2000) = -02d 58' 44"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a triple-peaked
structure with a duration of about 120 sec.  The peak count rate
was ~8500 counts/sec (15-350 keV), at ~72 sec after the trigger. 

The XRT began observing the field at 08:21:10.4 UT, 111.2 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 260.6530, -2.9728 which is equivalent to:
   RA(J2000)  = +17h 22m 36.72s
   Dec(J2000) = -02d 58' 22.1"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 65 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

The initial flux in the 2.5 s image was 8.65e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 120 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
0.63. 

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.)