GRB 190611A

B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), E.
Ambrosi  (INAF-IASFPA) , A. D'Ai (INAF-IASFPA), A. Tohuvavohu (PSU) and
V. D'Elia report on behalf of the Swift-XRT team:

We have analysed 4.7 ks of XRT data for GRB 190611A (D'Elia et al. GCN
Circ. 24785
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 ), from 117 s to 22.2 ks after the  BAT trigger. The data
comprise 15 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Goad et al. (GCN Circ. 24786
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 ).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.93 (+0.09, -0.08).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.48 (+0.24, -0.22). The
best-fitting absorption column is  8.5 (+8.2, -5.2) x 10^20 cm^-2,
consistent with the Galactic value of 3.2 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 4.5 x 10^-11 (4.9 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     8.5 (+8.2, -5.2) x 10^20 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.48 (+0.24, -0.22)

If the light curve continues to decay with a power-law decay index of
0.93, the count rate at T+24 hours will be 2.5 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.2 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/00907950.

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

GRB 190611A: Swift/UVOT Upper Limits

K. K. Simpson (PSU) and V. D'Elia (SSDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190611A
118 s after the BAT trigger (D'Elia et al., GCN Circ. 24785
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 ).
No optical afterglow consistent with the XRT position (Goad et al., GCN
Circ. 24786
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 )

RA (J2000): 21h 38m 53.44s
Dec (J2000): -56d 04' 27.3"

is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           118          268          147         >20.1
u_FC               276          525          246         >19.2
white              118          917          186         >20.0
u                  276          525          246         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).

R. Sanchez-Ramirez (INAF-IAPS), L. Izzo (HETH/IAA-CSIC), 
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. B. Malesani 
(DTU Space), D. A. Kann (HETH/IAA-CSIC) report on behalf 
of the Stargate collaboration:

We observed the field of GRB 190611A (D���Elia et al. GCN 24785
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 ) 
with FORS2, mounted on UT1 (Antu) of ESO VLT (Paranal 
observatory). Two V-band images were obtained in search of the 
possible afterglow, at a mean epoch of 12 June 08:10:32 UT 
(14.36 hr after the burst). In the combined exposure of 180s, no 
new source was detected within the enhanced XRT error circle 
(Goad et al. GCN 24786
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 ) down to a 3-sigma limit of V(AB) = 24.0 
mag. Photometric calibration was performed with respect to field 
stars from the NOMAD catalogue.

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), V. D'Elia (SSDC),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190611A (trigger #907950)
(D'Elia et al., GCN Circ. 24785
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 ).  The BAT ground-calculated position is
RA, Dec = 324.689, -56.070 deg which is
   RA(J2000)  =  21h 38m 45.3s
   Dec(J2000) = -56d 04' 12.6"
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows a single-peaked structure that starts
and peaks at ~T0, and ends at ~T+40 s. T90 (15-350 keV) is 41.8 +- 30.6 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.9 to T+63.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.88 +- 0.54.  The fluence in the 15-150 keV band is 4.6 +- 1.6 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+0.54 sec in the 15-150 keV band
is 0.9 +- 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/907950/BA/

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

Using 772 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 190611A, 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 = 324.72268, -56.07426 which is equivalent
to:

RA (J2000): 21h 38m 53.44s
Dec (J2000): -56d 04' 27.3"

with an uncertainty of 1.8 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.

V. D'Elia (SSDC), J.D. Gropp (PSU), N. J. Klingler (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), B. Sbarufatti (PSU), M. H. Siegel (PSU) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 17:49:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190611A (trigger=907950).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 324.769, -56.082 which is 
   RA(J2000) = 21h 39m 05s
   Dec(J2000) = -56d 04' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 10 sec.  The peak count rate
was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 17:50:55.4 UT, 113.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 324.72043, -56.07370 which
is equivalent to:
   RA(J2000)  = 21h 38m 52.90s
   Dec(J2000) = -56d 04' 25.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 102 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.25 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.3
(+3.64/-3.06) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 116 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 none of
the XRT error circle. 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 0.04. 

Burst Advocate for this burst is V. D'Elia (delia AT ssdc.asi.it). 
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/)