- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SIMBAD_NED NOTICE
NOTICE_DATE: Wed Apr 29 04:55:25 UTC 2009
NOTICE_TYPE: Swift-XRT Position search
TRIGGER_NUM: 350853
RA: 90.5548 (J2000)
DEC: -52.3855 (J2000)
SIMBAD search for XRT_RA,Dec=90.5548,-52.3855,radius=1.0arcmin
Num RA Dec Name Type Num_Pub Distance
NED search for XRT_RA,Dec=90.5548,-52.3855,radius=1.0arcmin
Num RA Dec Name Type Distance
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SIMBAD_NED NOTICE
NOTICE_DATE: Wed Apr 29 05:16:24 UTC 2009
NOTICE_TYPE: Swift-BAT Position search
TRIGGER_NUM: 350853
RA: 90.5593 (J2000)
DEC: -52.3860 (J2000)
SIMBAD search for BAT_RA,Dec=90.5593,-52.3860,radius=10.0arcmin
Num RA Dec Name Type Num_Pub Distance
1 90.51060667 -52.43272167 TYC 8113-1274-1 IR 0 3.32
2 90.51060667 -52.43272167 TYC 8113-1274-1 IR 0 3.32
NED search for BAT_RA,Dec=90.5593,-52.3860,radius=10.0arcmin
Num RA Dec Name Type Distance
1 90.672917 -52.488167 SUMSS J060241-522917 , RadioS 7.40
2 90.664042 -52.258722 2MASX J06023939-5215318 , IrS 8.50
3 90.693083 -52.256056 2MASX J06024636-5215219 , IrS 9.20
4 90.376750 -52.497833 SUMSS J060130-522952 , RadioS 9.50
- GCN NOTICE
TITLE: GCN/SIMBAD_NED NOTICE
NOTICE_DATE: Wed Apr 29 05:16:36 UTC 2009
NOTICE_TYPE: Swift-XRT Position search
TRIGGER_NUM: 350853
RA: 90.5548 (J2000)
DEC: -52.3855 (J2000)
SIMBAD search for XRT_RA,Dec=90.5548,-52.3855,radius=1.0arcmin
Num RA Dec Name Type Num_Pub Distance
NED search for XRT_RA,Dec=90.5548,-52.3855,radius=1.0arcmin
Num RA Dec Name Type Distance
- GCN Circular #9280
C. B. Markwardt (CRESST/GSFC/UMD), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:
At 04:53:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090429 (trigger=350853). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 90.559, -52.386 which is
RA(J2000) = 06h 02m 14s
Dec(J2000) = -52d 23' 09"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a broad peak
with a duration of about 25 sec. The peak count rate
was ~700 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 04:54:38.0 UT, 58.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 90.5548, -52.3855 which is equivalent to:
RA(J2000) = 06h 02m 13.15s
Dec(J2000) = -52d 23' 07.8"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 9.4 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.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 66 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.
Because this burst was detected as part of the sub-threshold program
(see GCN 8943) with a BAT image significance of only 5.64 sigma,
GCN notices were not generated until the source was confirmed
using XRT data.
Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt 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.)
- GCN Circular #9287
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
The onboard XRT position for GRB 090429A (Markwardt et al. GCN. Circ
9280) delivered as an XRT position notice and given in GCN 9280 was
incorrect. Inspection of the images reveals a cosmic ray 52 arcsec from
the GRB which affected the onboard centroid.
The correct position of the XRT afterglow is: RA, Dec= 90.5568, -52.3886
which is equivalent to:
RA(J2000) = 06 02 13.63
Dec(J2000) = -52 23 18.9
with an uncertainty of 4.8 arcsec (radius, 90% confidence).
This circular is an official product of the Swift-XRT team.
- GCN Circular #9289
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-61 to T+302 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090429A (trigger #350853)
(Markwardt, et al., GCN Circ. 9280). The BAT ground-calculated position is
RA, Dec = 90.573, -52.389 deg, which is
RA(J2000) = 06h 02m 17.5s
Dec(J2000) = -52d 23' 19.0"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a relatively smooth structure
with a couple overlapping peaks starting at ~T-12 sec and peaking at T_zero.
The main peak ends around T+40 sec with a long weak tail extending out
to ~T+200 sec. T90 (15-350 keV) is 188 +- 37 sec (estimated error
including systematics).
The time-averaged spectrum from T-10.8 to T+203.0 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.55 +- 0.22. The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.35 sec in the 15-150 keV band
is 0.6 +- 0.1 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/350853/BA/
- GCN Circular #9297
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 945 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090429A, 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 = 90.55469, -52.38758 which is equivalent
to:
RA (J2000): 06h 02m 13.13s
Dec (J2000): -52d 23' 15.3"
with an uncertainty of 3.2 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, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #9303
F. Olivares, T. Kruehler, J. Greiner (all MPE) report on behalf of the
GROND team:
We observed the field of GRB 090429A (Swift trigger 350853, Markwardt et
al.,GCN #9280) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m
ESO/MPI telescope at La Silla Observatory (Chile).
Observations started on 30 Apr. 2009 at 01:05 UT, 20.2 h after the burst,
and consisted of a set of images with a total integration time of 28 min in
JHK and 32 min in g'r'i'z'.
In stacked images we do not detect any object inside the enhanced XRT
errorcircle (Evans et al., GCN #9297) down to the following AB magnitudes:
g' > 23.4
r' > 23.3
i' > 22.6
z' > 22.2
J > 21.8
H > 20.7
K > 20.0
These upper limits have been obtained using 2MASS field stars and the GROND
zeropoints as reference.
- GCN Circular #9304
P.A. Evans (U. Leicester) and C. B. Markwardt (CRESST/GSFC/UMD) report
on behalf of the Swift-XRT team:
We have analysed 6 ks of XRT data for GRB 090429A (Markwardt et al. GCN
Circ. 9280). The first observation comprises a continuous observation
from T0+64 s to T0+255 s with the data entirely in Windowed Timing
(WT) mode. The second observation covers the range T0+35 to T0+64 ks,
and contains 5.8 ks of Photon Counting (PC) mode data. The enhanced XRT
position for this burst was given by Evans et al. (GCN. Circ 9297).
The first observation shows a number of flares superimposed on a short,
initial rise which breaks at T0+100s to a power-law decay with index 2.7
(+0.3, -0.2). The later PC mode data lie orders of magnitude above the
extrapolation of this decay; the addition of a break around T0+1 ks to a
decay with power-law index 0.56 (+0.12, -0.06) produces a good fit to
the data. Due to the large observing gap the behaviour of the light
curve in the interval T0+255 s to T0+35 ks is unknown; if it is more
complex than the simple behaviour we have modelled the final decay index
could differ significantly from the 0.56 (+0.12, -0.06) value we obtained.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+1.0, -0.7). The
best-fitting absorption column is 1.20 (+2.36, -0.77) x 10^21 cm^-2,
consistent with the Galactic value of 4.2 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 3.8 x 10^-11 (5.0 x 10^-11) erg
cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of
0.56, the count rate at T+48 hours will be 5.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x
10^-13 (2.9 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/00350853.
This circular is an official product of the Swift-XRT team.
- GCN Circular #9308
M. M. Chester (PSU), S. T. Holland (CRESST/GSFC/USRA) and
C. B. Markwardt (CRESST/GSFC/UMD) report on the behalf of the Swift
UVOT team:
The Swift/UVOT observed the field of GRB 090429A starting 49 s
after the BAT trigger (Markwardt, et al., 2009, GCN Circ. 9280).
Settled exposures started at T+67 s. We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT
afterglow (Evans, et al. 2009, GCN Circ. 9297). Preliminary 3-sigma
upper limits for detecting a source in the white finding chart and the
co-added images, using a 2.5 arcsecond radius circular aperture, are
Filter T_start T_stop Exp(s) Mag
----------------------------------------------
white (fc) 67 217 147 >21.7
v 35,736 58,902 114 >19.8
b 40,727 63,010 1697 >22.1
u 52,833 53,121 284 >21.0
uvw1 50,447 86,297 3336 >22.2
uvm2 44,777 47,341 659 >20.9
uvw2 34,829 57,197 1746 >21.9
white 63,015 63,137 120 >21.5
----------------------------------------------
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.06 mag (Schlegel, et al., 1998, ApJS, 500,
525). All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).
- GCN Circular #9318
Richard L. Pearson and J. Ward Moody report for Brigham Young
Univerisity's ROVOR team:
We observed the field around GRB 090429A (Swift trigger 350853,
Markwardt et al., GCN 9280) with the ROVOR (Robotic Observatory for
Variable Object Research) 16=94 telescope from Delta, Utah. Beginning 30
April 2009 at 03:46:50 UT (22.3 hours after outburst), observations
were obtained for a complete integration time of 50 minutes in white
light. No detection was made after stacking the images. Using the
magnitude limits established by Olivares et al., GCN Circ. 9303 on the
2.2m ESO/MPI telescope at La Silla Observatory, we estimate a
magnitude limit of 22 =B1 1 mag on these observations.
Previous IAU Circulars 