- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 02 May 05 09:26:02 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 116116, Seg_Num: 0
GRB_RA: 142.543d {+09h 30m 10s} (J2000),
142.617d {+09h 30m 28s} (current),
141.850d {+09h 27m 24s} (1950)
GRB_DEC: +17.002d {+17d 00' 07"} (J2000),
+16.978d {+16d 58' 42"} (current),
+17.222d {+17d 13' 19"} (1950)
GRB_ERROR: 4.00 [arcmin radius, statistical only]
GRB_INTEN: 6598 [cnts] Peak=500 [cnts/sec]
TRIGGER_DUR: 1.024 [sec]
TRIGGER_INDEX: 146 E_range: 25-100 keV
BKG_INTEN: 33617 [cnts]
BKG_TIME: 33928.00 SOD {09:25:28.00} UT
BKG_DUR: 8 [sec]
GRB_DATE: 13492 TJD; 122 DOY; 05/05/02
GRB_TIME: 33940.46 SOD {09:25:40.46} UT
GRB_PHI: 38.44 [deg]
GRB_THETA: 10.22 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 32.90 [sigma]
IMAGE_SIGNIF: 13.00 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +2 +13 +0 +0 +13 +1
SUN_POSTN: 39.64d {+02h 38m 33s} +15.46d {+15d 27' 36"}
SUN_DIST: 97.42 [deg]
MOON_POSTN: 330.55d {+22h 02m 13s} -16.69d {-16d 41' 09"}
MOON_DIST: 172.40 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 214.35, 42.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 139.43, 2.12 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is a rate trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
- red DSS finding chart
ps-file
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 02 May 05 09:26:54 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 116116, Seg_Num: 0
POINT_RA: 142.541d {+09h 30m 10s} (J2000)
POINT_DEC: +17.002d {+17d 00' 08"} (J2000)
GRB_DATE: 13492 TJD; 122 DOY; 05/05/02
GRB_TIME: 34003.21 SOD {09:26:43.21} UT
COUNTS: 5 Min_needed= 20
STD_DEV: 0.00 Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER: 1 Max_iter_allowed= 4
ERROR_CODE: 1
COMMENTS: SWIFT-XRT Nack Position.
COMMENTS: No source found in the image.
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 02 May 05 09:29:15 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 116116, Seg_Num: 0
GRB_RA: 142.543d {+09h 30m 10s} (J2000),
142.617d {+09h 30m 28s} (current),
141.850d {+09h 27m 24s} (1950)
GRB_DEC: +17.002d {+17d 00' 07"} (J2000),
+16.978d {+16d 58' 42"} (current),
+17.222d {+17d 13' 19"} (1950)
GRB_DATE: 13492 TJD; 122 DOY; 05/05/02
GRB_TIME: 33940.46 SOD {09:25:40.46} UT
TRIGGER_INDEX: 146
GRB_PHI: 38.44 [deg]
GRB_THETA: 10.22 [deg]
DELTA_TIME: 65460.00 [sec]
LC_URL: sw00116116000msb.lc
SUN_POSTN: 39.64d {+02h 38m 33s} +15.46d {+15d 27' 36"}
SUN_DIST: 97.42 [deg]
MOON_POSTN: 330.55d {+22h 02m 13s} -16.69d {-16d 41' 09"}
MOON_DIST: 172.40 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 214.35, 42.59 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 139.43, 2.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS: This does not match any source in the ground catalog.
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 02 May 05 09:34:20 UT
NOTICE_TYPE: Swift-XRT Lightcurve
TRIGGER_NUM: 116116, Seg_Num: 0
POINT_RA: 142.539d {+09h 30m 09s} (J2000)
POINT_DEC: +17.001d {+17d 00' 02"} (J2000)
LC_START_DATE: 13492 TJD; 122 DOY; 05/05/02
LC_START_TIME: 34005.90 SOD {09:26:45.90} UT
LC_STOP_DATE: 13492 TJD; 122 DOY; 05/05/02
LC_STOP_TIME: 34279.52 SOD {09:31:19.52} UT
LC_LIVE_TIME: 154.87 [sec], 56.6%
DELTA_TIME: 86126.38 [sec]
N_BINS: 100
TERM_COND: 0
LC_URL: sw00116116000msx.lc
SUN_POSTN: 39.64d {+02h 38m 33s} +15.46d {+15d 27' 36"}
SUN_DIST: 97.42 [deg]
MOON_POSTN: 330.56d {+22h 02m 15s} -16.68d {-16d 40' 54"}
MOON_DIST: 172.38 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 214.35, 42.59 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 139.43, 2.11 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-XRT Lightcurve.
- GCN notice #3328
Josh Rich, Brian Schmidt (Australian National University) and Jessie
Christiansen (UNSW) report on behalf of a larger collaboration:
"We observed a 5' region covering the BAT position of the SWIFT burst
GRB 050502B(GCN#3237)
using the ANU 1m telescope on May 2.40 UT in V band. Preliminary
comparison with the DSS shows no OT to V=18.
Further observations are continuing."
- GCN notice #3330
A. Falcone, D. N. Burrows, M. Chester (PSU), P. Schady (MSSL),
J. Cummings (GSFC/NRC), D. Palmer (LANL), C. Pagani (PSU), B. Zhang (UNLV),
K. Page, M. Goad (U.Leicester), N. Gehrels (GSFC)
on behalf of the Swift Team.
At 09:25:40 UT, the Swift Burst Alert Telescope (BAT) triggered
and located GRB050502b (trigger=116116). The BAT on-board
calculated location is RA, Dec = 142.543, +17.002
(09:30:10, +17:00:07) (J2000) with an uncertainty of
3 arcmin (radius, 3-sigma, including estimated
systematic uncertainty). The BAT light curve showed a 7-second
long peak with complex structure from t-4 to t+3. The
maximum count rate was 4000 counts per second (15-350 keV)
in the 1 second time interval centered around t+1.
The spacecraft slewed promptly and the XRT began observations
at 09:26:43 UT. The initial centroiding image detected only
5 counts, insufficient to produce a centroid. Further analysis
will require the ground-processed data, which will be available
at the Swift MOC at about 12:30 UT.
The Swift Ultra Violet/Optical (UVOT) observations began at
09:26:40 UT, 60 seconds after the BAT trigger. The first
data taken after the spacecraft settled was a 100 sec
exposure using the V filter with the midpoint of the
observation at 135 sec after the BAT trigger. This image
was sent directly to the ground via TDRSS with the FOV pixel
binning set at 8 x 8 to reduce telemetry. A comparison against
the USNO-B1 reveals a new source inside the BAT error circle
at RA, Dec 09:30:12.58, +17:02:00.7 (J2000). This is 118 arcseconds from
the BAT position. The V-band magnitude was 17.7 +/- 0.1.
- GCN notice #3331
Joshua Rich, Brian Schmidt (Australian National University) and Jessie
Christiansen (UNSW) report on behalf of a larger collaboration:
Images taken with ANU 1m telescope show no source at the position of the
SWIFT OT reported by Falcone et al. (GCN 3330) at the following
(approximate) limits
Band Time (UT) Age (Minutes) Limit
V 9:35 9 V>19
V 9:48 22 V>21
I 9:58 32 I>20.5
This message may be cited.
- GCN notice #3333
C. Pagani, A. Falcone, D. N. Burrows, J. Kennea, S. Kobayashi (PSU), F.
Marshall, and Neil Gehrels (GSFC) report on behalf of the Swift XRT team:
The Swift XRT observed GRB 050502b (Falcone et al., GCN 3330) beginning at
09:26:43 UT. As reported in GCN 3330, the XRT obtained only 5 photons in
its initial centroiding image and was not able to report a prompt
centroid. Analysis of the first orbit of data reveals a bright, transient,
uncataloged X-ray source at the following position:
RA(J2000) = 09:30:10.1
Dec(J2000) = +16:59:44.3
The estimated uncertainty is 5 arcseconds radius (90% containment). We
note that this position is 23.1 arcseconds from the BAT position reported
in GCN 3330, and 141 arcseconds from the UVOT position reported in GCN 3330.
- GCN notice #3334
K. Sanchawala, W.L. Wu, K.Y. Huang, W.H. Ip(NCU),
Y. Qiu, W. Zhou (BAO), Y.Q. Lou (THCA), Y. Urata (RIKEN)
on behalf of the EAFON report:
" We have imaged the Swift XRT position of GRB 050502b (Pagani. C. et
al., GCN 3333) using 1-m telescope at Lulin Observatory, Taiwan. The R
band observations started from 13.45 UT (~ 3.98 hours after the
burst). The limiting magnitude of R-band co-added image is R~21.8
compared with USNO-B1.0 stars. No source was detected under the
limiting magnitude at the XRT position."
This message may be cited.
- GCN notice #3337
P. Schady (MSSL), A. Falcone (PSU), S. Holland (GSFC/NRC), S. Koch (PSU), A.
Breeveld, K. Mason (MSSL), J. Nousek (PSU), N. Gehrels (GSFC) on behalf of the
UVOT Swift team
On further analysis of the Swift UVOT data, the afterglow candidate reported in
GCN 3330 (Falcone et al.) is not observed in the 1 x 1 binned first 100 sec
exposure taken in the V filter.
Starting with data taken ~192s after the BAT trigger (Falcone et al., GCN 3330)
we have co-added the early time data of GRB 050502b in each of the UVOT V, B
and U bands. The co-added images are made up of 9 x 10s exposures. No source is
detected at the position of the afterglow candidate reported in GCN 3330
(Falcone et al.) or within the XRT error circle (Pagani et al., GCN 3333) in
any of the bands. We estimate the five sigma magnitude upper limits from the
co-added images to be:
Filter Upper limit
V 18.5
B 19.4
U 19.2
The magnitudes are based on preliminary zero-points, measured in orbit,
and will require refinement with further calibration.
- GCN notice #3338
Joshua Rich, Brian Schmidt (Australian National University) and Jessie
Christiansen (UNSW) report on behalf of a larger collaboration:
Images taken with ANU 1m telescope show a source within the
SWIFT XRT error circle (Pagani et al., GCN 3333) at I=19.5 located at
RA=09:30:10.024 DEC=+16:59:48.07 J2000. This object does not vary by
more than +/- 0.1 mag from 2 May 2005 UT 9:58 through to UT 11:05. The
object is not
detected in V to V>21. The object is 4.01+/-0.1 mag fainter than the
star located at
RA=09:30:12.616 DEC=+17:00:05.55 in I.
This message may be cited.
- GCN notice #3339
J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
M. Suzuki (Saitama), M. Tashiro (Saitama U.), J. Tueller (GSFC),
on behalf of the Swift/BAT team:
At 09:25:40 UT, the Swift Burst Alert Telescope (BAT) triggered
and located GRB050502B (trigger=116116) (GCN Circ 3330, Falcone
et al.). The refined BAT ground position is (RA,Dec) = 142.543,
+17.002, [deg; J2000] +- 3 arcmin, (95% containment). This is
24 arc seconds from the position determined by the XRT (GCN Circ
3333, Pagani, et al.). The burst was 10 degrees off the Swift
boresight, within the fully-coded BAT field of view.
The BAT mask-weighted light curve shows one main peak of about 6
seconds duration centered at the trigger time preceded by two
smaller peaks 16 and 10 seconds earlier with a softer spectrum.
T90 (15-350 keV) is (17.5 +- 0.2) seconds (estimated error
including systematics).
The spectrum is well fit by a single power law with photon index
of 1.6 +- 0.1. The fluence in the 15-350 keV band is
(8.0 +- 1.0) x 10^-7 erg/cm2. The peak photon flux in the 15-350
band is (1.73 +- 0.15) ph/cm2/s. All the quoted errors are at the
90% confidence level.
We note that this burst appears to be well-suited for ground
follow-up observations, as it is located 90 degrees from the Sun,
180 degrees from the Moon, close to the ecliptic, and away from
the Galactic center.
- GCN notice #3346
The field of GRB 050502b (GCN 3330, 3333) was observed by B.C. Bhatt,
S. Ramya and G.C. Anupama on 2005 May 2, 14:45 UT, using the 2-m Himalayan
Chandra Telescope, Indian Astronomical Observatory, Hanle. The co-added 40
min (4 x 600s) R frame does not show any optical transient down to
R ~ 22.5 mag.
This message may be quoted in publications.
-- T.P. Prabhu, on behalf of the GRB followup team of Indian Astronomical
Observatory, Hanle
- GCN notice #3350
Kuntal Misra, S. B. Pandey (ARIES Naini Tal), on behalf of larger Indian
GRB collaboration
We observed the SWIFT burst (trigger = 116116) using 1-m Sampurnanand
Telescope at ARIES, Naini Tal. The observations were carried out in V band
(12*300sec). In the combined V band image (around May 02.654 UT, mean
epoch of observations), we did not reveal any new source down to ~ 21.5
mag, in comparison to a nearby star 09:30:06.62 +16:58:59.0 (V mag 15.992).
This message may be cited.
- GCN notice #3357
S. Bradley Cenko, Derek B. Fox (Caltech), Joshua Rich, Brian Schmidt
(ANU), Jessie Christiansen (UNSW), and Edo Berger (Carnegie) report:
We have further analyzed our images of the field of GRB050502b (GCN
3330) taken with the 1-m ANU telescope (GCN 3338). Additionally, we
have imaged the field with the automated Palomar 60-inch telescope
(P60). Observations at the P60 consisted of 10 x 120 s exposures in the
Gunn i band taken at a mean epoch of 5:40 4 May 2005 UT (43.8 hours
after the burst).
Based on extrapolations from the 2MASS and USNO-B2 catalogs, we adopt
values of V=16.7, I=15.8, R=16.1 for the star located at RA =
09:30:12.616, Dec = +17:00:05.55 (J2000.0). We find the magnitude of
the afterglow candidate identified by Rich, Schmidt, and Christiansen
(GCN 3338) as follows:
Filter Facility UT Age Limit (3-sig) or measure
========================================================
V ANU1m 9:35 May 2 9.5 min V>20.7
V ANU1m 9:41 May 2 15 min V>20.2
V ANU1m 9:43 May 2 18 min V>20.8
V ANU1m 9:46 May 2 20 min V>21.8
I ANU1m 9:58 May 2 23 min I=19.84+/-0.09
i P60 5:40 May 4 43.8 hr i>21.7
We therefore identify this source as the afterglow of GRB050502b. To
reiterate the coordinates (J2000.0):
RA: 09:30:10.024
Dec: +17:00:05.55
Finally, we note the spectral slope at early times, beta > 2.9,
indicates that GRB050502b may be either highly extinguished or at
moderately high redshift.
- GCN notice #3358
Correction to OT Coordinates
S. Bradley Cenko, Derek B. Fox (Caltech), Joshua Rich, Brian Schmidt
(ANU), Jessie Christiansen (UNSW), and Edo Berger (Carnegie) report:
We have further analyzed our images of the field of GRB050502b (GCN
3330) taken with the 1-m ANU telescope (GCN 3338). Additionally, we
have imaged the field with the automated Palomar 60-inch telescope
(P60). Observations at the P60 consisted of 10 x 120 s exposures in the
Gunn i band taken at a mean epoch of 5:40 4 May 2005 UT (43.8 hours
after the burst).
Based on extrapolations from the 2MASS and USNO-B2 catalogs, we adopt
values of V=16.7, I=15.8, R=16.1 for the star located at RA =
09:30:12.616, Dec = +17:00:05.55 (J2000.0). We find the magnitude of
the afterglow candidate identified by Rich, Schmidt, and Christiansen
(GCN 3338) as follows:
Filter Facility UT Age Limit (3-sig) or measure
========================================================
V ANU1m 9:35 May 2 9.5 min V>20.7
V ANU1m 9:41 May 2 15 min V>20.2
V ANU1m 9:43 May 2 18 min V>20.8
V ANU1m 9:46 May 2 20 min V>21.8
I ANU1m 9:58 May 2 23 min I=19.84+/-0.09
i P60 5:40 May 4 43.8 hr i>21.7
We therefore identify this source as the afterglow of GRB050502b. To
reiterate the coordinates (J2000.0):
RA 09:30:10.024
DEC +16:59:48.07
Finally, we note the spectral slope at early times, beta > 2.9,
indicates that GRB050502b may be either highly extinguished or at
moderately high redshift.
- GCN notice #3421
M. Sasaki, N. Manago, K. Noda, Y. Asaoka report on behalf of the Ashra collaboration:
We have observed the field of GRB050502b (09:25:40 UT) covering the SWIFT XRT error circle
(Pagani et al., GCN 3333) by the Ashra-AFT (Automated Follow-up for Transients) telescope
at the Haleakala observatory in Hawaii (latitude = 20d 42' 37" N, longitude = 156d 15' 31" W,
altitude = 3020m). The telescope (12" Meade LX200GPS with a KAI-2020M CCD) is served as a
follow-up detector to quickly respond to triggers from Ashra optical transient survey monitor
as well as from GRB satellites.
The telescope automatically slewed to the GRB and took the first image of 1.4sec-exposure
at 09:26:36 UT (56 seconds after the burst and 32 seconds after the BAT alert socket).
We also took following 363 images of 4sec-exposure every 9 to 10 seconds (09:26:36 UT - 10:25:47 UT).
These images are unfiltered to maximize the detection sensitivity, of which peak is between B and V.
No new source was found within the SWIFT XRT position. From the earliest 4 images and the co-added
images (3 x 4sec, 25 x 4sec), we preliminarily obtained 4-sigma limiting magnitudes of B1 and R1
in the USNO-B1.0 catalog as follows.
-----------------------------------------------------
start end exposure limit mag.
after GRB (s) (s) B1 R1
-----------------------------------------------------
56.0 57.4 1.4 16.2 14.6
66.0 70.0 4.0 16.9 15.5
76.0 80.0 4.0 16.2 14.6
85.0 89.0 4.0 16.2 14.6
-----------------------------------------------------
66.0 89.0 12.0 17.2 16.2
66.0 294.0 100.0 18.5 17.0
-----------------------------------------------------
URL: http://www.icrr.u-tokyo.ac.jp/~ashra/GRB050502b/
This message can be cited.
- GCN notice #4113
K. Torii (Osaka U.) reports on behalf of the ART collaboration:
The error region of the bright GRB 050502b (Falcone et al. GCN 3330)
was observed by the 14 inch Automated Response Telescope. Ic band
imaging was started at 2005 May 2 10:19:30 UT (54 minutes after the
burst) and 60s exposure was repeated.
The optical afterglow (Rich et al. GCN 3338) is not detected in our
frames and the following 3-sigma upper limit is derived for a stacked
image.
------------------------------------------
StartUT-EndUT Filter Limit Exposure
------------------------------------------
10:55:59-13:00:20 Ic >18.6 87x60s
------------------------------------------
- astro-ph/0512615 from 27 Dec 2005
Falcone: The Giant X-ray Flare of GRB 050502B: Evidence for Late-Time Internal
Until recently, X-ray flares during the afterglow of gamma ray bursts (GRBs)
were a rarely detected phenomenon, thus their nature is unclear. During the
afterglow of GRB 050502B, the largest X-ray flare ever recorded rose rapidly
above the afterglow lightcurve detected by the Swift X-ray Telescope. The peak
flux of the flare was >500 times that of the underlying afterglow, and it
occurred at >12 minutes after the nominal prompt burst emission. The fluence of
this X-ray flare, (1.0 +/- 0.05) x 10^{-6} erg cm^{-2} in the 0.2-10.0 keV
energy band, exceeded the fluence of the nominal prompt burst. The spectra
during the flare were significantly harder than those measured before and after
the flare. Later in time, there were additional flux increases detected above
the underlying afterglow, as well as a break in the afterglow lightcurve. All
evidence presented below, including spectral and particularly timing
information during and around the giant flare, suggests that this giant flare
was the result of internal dissipation of energy due to late central engine
activity, rather than an afterglow-related effect. We also find that the data
are consistent with a second central engine activity episode, in which the
ejecta is moving slower than that of the initial episode, causing the giant
flare and then proceeding to overtake and refresh the afterglow shock, thus
causing additional activity at even later times in the lightcurve.
- 1008.4364 from 27 Aug 10
Davide Lazzati et al.: X-ray flares from propagation instabilities in long Gamma-Ray Burst jets
We present a numerical simulation of a gamma-ray burst jet from a long-lasting engine in the core of a 16 solar mass Wolf-Rayet star. The
engine is active for 6000 s with a luminosity that decays in time as a power-law with index -5/3. Even though there is no short time-scale
variability in the engine luminosity, we find that the jet's kinetic luminosity outside the progenitor star is characterized by fluctuations
with relatively short time scale. We analyze the temporal characteristics of those fluctuations and we find that they are consistent with the
properties of observed flares in the X-ray afterglows. The peak to continuum flux ratio of the flares in the simulation is consistent with
some, but not all, the observed flares. We propose that propagation instabilities, rather than variability in the engine luminosity, may be
responsible for the X-ray flares with moderate contrast. Strong flares such as the one detected in GRB 050502B, instead, cannot be reproduced
in this model and require strong variability in the engine activity.
- 1011.0113 from 2 Nov 10
P. Afonso et al.: GRB 050502B optical afterglow: a jet break at high redshift
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Aims: GRB 050502B is well known for the very bright flare displayed in its X-ray light curve. Despite extensive studies, however, the optical
light curve has never been discussed and its redshift is unconstrained. Possible correlations between optical and X-ray data are analysed.
Methods: Photometric data from TNG in the R and I bands were used to compare the optical afterglow with the X-ray light curve. The HyperZ
package and a late time VLT host observation were used to derive redshift estimates. Results: The I-band afterglow decay followed a power-law
of index {\alpha} = 2.1 $\pm$ 0.6, after a late break at ~ $1.3 \times 10^5$ s. The R - I color is remarkably red and the broadband spectral
index {\beta}_OX = $0.9 \pm 0.1$ is consistent with the X-ray spectral slope {\beta}_X. Although a photometric redshift of z > 4 is the most
conservative result to consider, a photometric redshift of z = 5.2 $\pm$ 0.3 is suggested with no extinction in the host, based on which an
isotropic energy E_{\gamma},iso = $(3.8 \pm 0.7) \times 10^52$ erg and a jet opening angle {\theta} ~ $3.7^{\circ}$ are subsequently derived.
Conclusions: The combined X-ray and optical data suggest an achromatic break, which we interpret as a jet break. The post jet break slope obeys
roughly the closure relation for the jet slow cooling model. Because of the afterglowâs very red color, in order for the redshift to be low (z
< 1), extinction, if present in the host, must be significantly high. Since the optical-to-X-ray index is consistent with the X-ray spectrum,
and there is no XRT evidence for excess N_H, GRB 050502B was likely at high redshift.
Previous IAU Circulars 