GRB 130608A

H. A. Krimm (CRESST/GSFC/USRA), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC),
A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D. M. Palmer (LANL)
and T. N. Ukwatta (MSU) report on behalf of the Swift Team:

At 23:14:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130608A (trigger=557771).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 24.580, +41.494 which is 
   RA(J2000) = 01h 38m 19s
   Dec(J2000) = +41d 29' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve suggests a broad weak peak
from T-20 to T+40 s.  The maximum count rate was ~500 counts/sec 
(15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 23:17:02.9 UT, 161.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 24.6087,
41.5027 which is equivalent to:
   RA(J2000)  = 01h 38m 26.08s
   Dec(J2000) = +41d 30' 09.7"
with an uncertainty of 2.7 arcseconds (radius, 90% containment). This
location is 83 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 in excess of the Galactic value (6.62 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 6.2
(+5.87/-4.48) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 4.77e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 168 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
0.06. 

Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.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.)

J.C.Tello, M.Jelinek, (IAA-CSIC) J.Gorosabel (UPV-EY, IAA-CSIC),
A.J.Castro-Tirado, R. Sanchez-Ramirez (IAA-CSIC), on behalf of a larger
collaboration report:

We observed the field of GRB130608A (Krimm et al. GCNC 14827) with the
BOOTES-2/TELMA telescope located in Malaga, Spain, starting at 02h31m UT
(136 minutes after the burst, when the source rose above the local
horizon). No new source is visible within the XRT error circle.

During a first epoch we combined 11 images with an unfiltered exposure of
60 seconds each that begun at 02h31m45s (136 minutes after the burst) and
ended at 02h44m21s (mean time 142 minutes after the burst), and a limiting
magnitude of 18.8 was obtained when compared to the values of R2Mag of the
field stars as stated in the USNO-B1 catalog.

During a 2nd epoch we combined 22 images with an unfiltered exposure of 60
seconds each that begun at 3h00m11s (165 minutes after the burst) and ended
at 3h22m08s (mean time 176 minutes after the burst), and we obtained a
limiting magnitude of 19.5 when compared to the values of R2Mag of the
field stars as stated in the USNO-B1 catalog.

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

Using 952 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 130608A, 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 = 24.61111, +41.50289 which is equivalent
to:

RA (J2000): 01h 38m 26.67s
Dec (J2000): +41d 30' 10.4"

with an uncertainty of 1.7 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.

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), A. Y. Lien (NASA/GSFC/ORAU),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130608A (trigger #557771)
(Krimm, et al., GCN Circ. 14827
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 ).  The BAT ground-calculated position is
RA, Dec = 24.594, 41.485 deg, which is 
   RA(J2000)  =  01h 38m 22.5s 
   Dec(J2000) = +41d 29' 05.0" 
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 45%.
 
The mask-weighted light curve shows a broad peak starting at ~T-25 sec,
peaking at ~T+5 sec, and ending at ~T+50 sec.  T90 (15-350 keV) is
44.4 +- 8.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T-25.56 to T+24.18 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
3.21 +- 0.34.  The fluence in the 15-150 keV band is 6.4 +- 1.0 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+19.06 sec in the 15-150 keV band
is 0.6 +- 0.3 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/557771/BA/

Alan M. Watson (UNAM), Nat Butler (ASU), 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), 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 130608A (Krimm, et al., GCN 14827
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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 in morning twilight from 2013/06
9.46 to 2013/06 9.47 UTC (11.70 to 12.00 hours after the BAT trigger),
obtaining a total of 0.20 hours exposure in the r' and i' bands and 0.08
hours exposure in the Z, Y, J, and H bands.

For a source within the Swift-XRT error circle (Beardmore, et al., GCN
14832
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 ), in comparison with the RATIR zero points and 2MASS, we obtain
the following upper limits (3-sigma):

 r'    > 21.90
 i'    > 22.27
 Z     > 21.21
 Y     > 20.64
 J     > 20.12
 H     > 19.80

These magnitudes are in the AB system and not corrected for Galactic
extinction in the direction of the GRB.

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

K.L. Page (U. Leicester), C. Pagani (U. Leicester), V. Mangano
(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),
M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A.P. Beardmore
(U. Leicester) and H.A. Krimm report on behalf of the Swift-XRT team:

We have analysed 9.4 ks of XRT data for GRB 130608A (Krimm  et al. GCN
Circ. 14827
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 ),  from 147 s to 47.3 ks after the	BAT trigger. The data
comprise 98 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN. Circ 14832).

The light curve can be modelled with an initial power-law decay with an
index of alpha=4.33 (+0.26, -0.23), followed by a break at T+653 s to
an alpha of 0.40 (+0.11, -0.12).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 3.23 (+0.27, -0.25). The
best-fitting absorption column is  1.0 (+0.4, -0.3) x 10^21 cm^-2, in
excess of the Galactic value of 6.6 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.40 (+0.36, -0.11)
and a best-fitting absorption column consistent with the Galactic
value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.0 x 10^-11 (4.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     0 (+4.9, -0) x 10^20 cm^-2
Galactic foreground: 6.6 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.40 (+0.36, -0.11)

If the light curve continues to decay with a power-law decay index of
0.40, the count rate at T+24 hours will be 7.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x
10^-13 (3.0 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00557771.

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

H. A. Krimm (GSFC/USRA)for the Swift-BAT team:

Using the full data set from T-239 to T+963 sec,we report further
analysis of BAT GRB 130608A (trigger #557771)(Krimm, et al.,
GCN Circ. 14827
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 ; Krimm, et al., GCN Circ. 14833
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 ). Information in
this Circular supersedes that presented in Krimm, et al., GCN Circ. 14833
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 .

The BAT ground-calculated position isrefined to RA, Dec = 24.597,
41.492 deg which is
    RA(J2000)  =  01h 38m 23.3s
    Dec(J2000) = +41d 29' 30.5"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 45%.

The initial Swift-BAT circular reported a broad peak starting at
~T-25 sec, peaking at ~T+5 sec, and ending at ~T+50 sec. With further
data available we see that the mask-weighted light curve contains
precursor emission from~T-150 sec to ~T-90. BAT did not trigger on
this precursor because it occurred during a slew to the field containing
the burst.  T90 (15-350 keV) is 151.38 +- 10.84 sec (estimated error
including systematics).

The time-averaged spectrum from T-134.19 to T+22.20 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.71 +- 0.41.  The fluence in the 15-150 keV band is 9.0 +- 1.9 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+19.06 sec in the 15-150 keV band
is 0.6 +- 0.3 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/557771/BA/

A. Volnova (IKI), V. Linkov (ISON), M.Suvorov (ISON), V. Nevskiy (ISON), 
D. Ivanov (ISON),  I. Molotov (KIAM), A. Pozanenko (IKI),  report on 
behalf of larger collaboration:

We observed the field of  GRB 130608A (Krimm  et al., GCN 14827
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 ) with
SANTEL-400AN (0.4-m f/3)  telescope of ISON-Kislovodsk observatory.
Observations started on  Jun. 09 (UT) 00:01:42.   We obtained  several
unfiltered images  of 60 s exposure. We do not detect any source within 
enhanced XRT error circle (Beardmore et al., GCN 14832
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 ). Preliminary 
photometry of combined image is based on USNO-B1.0 (R2) nearby  stars:

T_start,             T0+,      Exp,   Filter,  UL (3 sigma)
(UT)                 mid (d)   (s)

2013-06-09T00:01:42  0.04170   960    none     >18.1

S. T. Holland (STScI) and Hans Krimm (CRESST/GSFC/USRA) report on
behalf of the Swift/UVOT team:

    The Swift/UVOT began settled observations of the field of GRB
130608A starting 168 s after the BAT trigger (Krimm et al. 2013, GCNC
14827).  We do not detect any new source consistent with the
UVOT-enhanced XRT position (Beardmore 2013, GCNC 14832) in any of the
UVOT exposures.  Preliminary 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the finding chart (FC) exposures and initial summed exposures are
presented below.

Filter      TSTART      TSTOP   Exposure      Mag
-------------------------------------------------
white (FC)     169        318        147    >21.0
               607        626         19    >19.6
u (FC)         327        576        246    >20.1
               731        750         19    >18.4
-------------------------------------------------
v              657     12,041       1154    >20.6
b              583       6742        452    >20.8
u             4899       6536        393    >20.5
uvw1           706       6331        432    >20.6
uvm2           681     12,759       1134    >21.3
uvw2           632     11,127       1199    >21.5
white          858       6946        560    >21.5
-------------------------------------------------

    The quoted upper limits have not been corrected for the expected
extinction due to the Galactic reddening along the line of sight to
this burst of E(B-V) = 0.05 mag (Schlafly et al. 2011, ApJS, 737,
103).