- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 May 05 00:08:48 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 130088, Seg_Num: 0
GRB_RA: 278.144d {+18h 32m 35s} (J2000),
278.198d {+18h 32m 48s} (current),
277.640d {+18h 30m 34s} (1950)
GRB_DEC: +26.340d {+26d 20' 23"} (J2000),
+26.344d {+26d 20' 39"} (current),
+26.302d {+26d 18' 06"} (1950)
GRB_ERROR: 4.00 [arcmin radius, statistical only]
GRB_INTEN: 1827 [cnts] Peak=347 [cnts/sec]
TRIGGER_DUR: 0.064 [sec]
TRIGGER_INDEX: 10418 E_range: 25-100 keV
BKG_INTEN: 42370 [cnts]
BKG_TIME: 160.00 SOD {00:02:40.00} UT
BKG_DUR: 8 [sec]
GRB_DATE: 13515 TJD; 145 DOY; 05/05/25
GRB_TIME: 173.26 SOD {00:02:53.26} UT
GRB_PHI: 19.05 [deg]
GRB_THETA: 26.04 [deg]
SOLN_STATUS: 0x3
RATE_SIGNIF: 81.28 [sigma]
IMAGE_SIGNIF: 18.00 [sigma]
MERIT_PARAMS: +1 +0 +0 +0 +2 +43 +0 +0 +51 +1
SUN_POSTN: 61.90d {+04h 07m 36s} +20.93d {+20d 55' 42"}
SUN_DIST: 121.07 [deg]
MOON_POSTN: 258.31d {+17h 13m 15s} -27.30d {-27d 18' 08"}
MOON_DIST: 56.96 [deg]
MOON_ILLUM: 98 [%]
GAL_COORDS: 54.96, 15.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 281.26, 49.46 [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: Wed 25 May 05 00:10:34 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 130088, Seg_Num: 0
GRB_RA: 278.144d {+18h 32m 35s} (J2000),
278.198d {+18h 32m 48s} (current),
277.640d {+18h 30m 34s} (1950)
GRB_DEC: +26.340d {+26d 20' 23"} (J2000),
+26.344d {+26d 20' 39"} (current),
+26.302d {+26d 18' 06"} (1950)
GRB_DATE: 13515 TJD; 145 DOY; 05/05/25
GRB_TIME: 173.51 SOD {00:02:53.51} UT
TRIGGER_INDEX: 10418
GRB_PHI: 19.05 [deg]
GRB_THETA: 26.04 [deg]
DELTA_TIME: 65510.00 [sec]
LC_URL: sw00130088000msb.lc
SUN_POSTN: 61.90d {+04h 07m 36s} +20.93d {+20d 55' 42"}
SUN_DIST: 121.07 [deg]
MOON_POSTN: 258.31d {+17h 13m 15s} -27.30d {-27d 18' 08"}
MOON_DIST: 56.96 [deg]
MOON_ILLUM: 98 [%]
GAL_COORDS: 54.96, 15.54 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 281.26, 49.46 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
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.
- GCN/SWIFT NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 May 05 00:13:34 UT
NOTICE_TYPE: Swift-XRT Lightcurve
TRIGGER_NUM: 130088, Seg_Num: 0
POINT_RA: 278.138d {+18h 32m 33s} (J2000)
POINT_DEC: +26.311d {+26d 18' 40"} (J2000)
LC_START_DATE: 13515 TJD; 145 DOY; 05/05/25
LC_START_TIME: 301.46 SOD {00:05:01.46} UT
LC_STOP_DATE: 13515 TJD; 145 DOY; 05/05/25
LC_STOP_TIME: 607.15 SOD {00:10:07.15} UT
LC_LIVE_TIME: 50.78 [sec], 16.6%
DELTA_TIME: 86094.31 [sec]
N_BINS: 37
TERM_COND: 1
LC_URL: sw00130088000msx.lc
SUN_POSTN: 61.90d {+04h 07m 36s} +20.93d {+20d 55' 43"}
SUN_DIST: 121.10 [deg]
MOON_POSTN: 258.33d {+17h 13m 20s} -27.31d {-27d 18' 18"}
MOON_DIST: 56.92 [deg]
MOON_ILLUM: 98 [%]
GAL_COORDS: 54.93, 15.53 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 281.25, 49.43 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-XRT Lightcurve.
COMMENTS: This Lightcurve was terminated by the 'Time' condition.
- GCN notice #3465
E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), report on
behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,
responded to GRB 050525A (Swift trigger 130088). The first image was at
00:08:56.7 UT, 363.5 s after the burst (8.7 s after the GCN notice
time). The unfiltered images are calibrated relative to USNO A2.0. We
detect a 14.7 magnitude, fading source at:
18:32:32.76 +26:20:22.65 (J2000)
start UT mag mlim(of image)
----------------------------------
00:08:56.7 14.7 15.4
This source is not visible in DSS (second epoch), 2MASS or the MPChecker
database.
Continuing observations are in progress.
- GCN notice #3466
D. Band (GSFC/UMBC), J. Cummings (GSFC/NRC), M. Perri
(ASDC), S. Holland (GSFC/USRA), D. N. Burrows (PSU), N.
Gehrels (GSFC), J. E. Hill, J. A. Kennea, S. Hunsberger
(PSU), C. Markwardt (GSFC/UMD), D. Palmer (LANL) on behalf
of the Swift Team.
At 00:02:53 UT, the BAT instrument on the Swift spacecraft
triggered (trigger=130088) and located GRB 050525. The BAT
on-board calculated location is RA,Dec 278.144 , +26.340
(18h 32m 35s +26d 20' 23") (J2000) with an uncertainty of 3
arcmin (radius, 3-sigma, including systematic uncertainty).
This is a very bright burst, yielding about 1500 counts
over background in 64 ms (preliminary) in the 25-100 keV
range in the BAT instrument. This would correspond to a
rate of 10 counts/sec/cm2 in that 64 ms interval, but the
peak rate in a later interval may be greater. Although
light curves are not yet available, the BAT rate trigger
continued to evaluate different timescales while data from
the first 64 ms was being imaged. The merit parameters
indicate that the highest significance rate trigger is for
a 1 second interval, consistent with a short burst. More
details will be available after the full data pass.
The XRT was pointed promptly at the burst and took an image
at 00:04:58 UT (125 s after the BAT burst trigger). The
XRT found a bright X-ray source near the center of the
field of view, with position RA(J2000) = 18h 32m 32.3s
Dec(J2000) = +26d 20' 17.5" We estimate an uncertainty of
about 6 arcseconds radius (90% containment). This position
is 31 arcseconds from the BAT position and 8 arcseconds
from the ROTSE position (Rykoff et al, GCN 2465).
We caution that the XRT is in the middle of engineering
tests and is in an unusual mode. While the X-ray afterglow
looks unusually strong, there are also indications that the
XRT instrument configuration is abnormal due to the tests
being performed.
The XRT position is outside of the UVOT-TDRSS image.
Analysis of the UVOT data will take place after the next
full data pass.
This is a bright burst that appears to be in the short
category; the Sun and moon angles are conducive for optical
observations. Followup observations are strongly
encouraged.
- GCN notice #3467
C. Markwardt (GSFC/UMD), S. Barthelmy (NASA/GSFC), L. Barbier (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
M. Suzuki (Saitama), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
GRB 050525 (Swift trigger 130088) was observed by Swift BAT. At the
present, only rate data are available. This initial data indicate
that the burst was very intense (peak rate of 80,000 ct/s above
background). The light curve consists of at least two ragged peaks,
with a total duration of approximately 10 seconds (15 - 200 keV).
Thus, this is not a short burst as initially speculated (Band et
al. GCN #3466), but it is one of the brightest bursts of the year.
- GCN notice #3468
E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), R. Quimby (U
Texas), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site in Namibia, and ROTSE-IIId at
the Turkish National Observatory in Turkey responded automatically to
Swift GRB 050525 (GCN 3466, 3467). Our first 5-s exposure from
ROTSE-IIIc begain at 00:08:56.7 UT; the response in Turkey was delayed
approximately 30 minutes due to bad weather. The images in Namibia were
affected by clouds passing through the images.
We confirm the fading nature of the afterglow reported in GCN 2465. The
afterglow is well detected in images from both ROTSE-IIIc and
ROTSE-IIId. The afterglow is 9" (3 pixels) from a 17.2 magnitude USNO
star, which affected our initial position estimate. The revised
position is:
18:32:32.6 +26:20:23.5 (J2000)
with an uncertainty of ~1". We note that this is 7.2" from the XRT
position reported by Band et al (GCN 2465).
We have measured the afterglow flux with our PSF fitting software and
have found that the early lightcurve is fading with a slow power-law
decline with index ~-0.5, with a peak of 15.1+/-0.1 at 601s post-burst.
The images are unfiltered and calibrated relative to USNO B1.0 R-band
magnitudes. This bright afterglow with a slow decline should still be
bright for follow-up spectroscopy.
An image of the afterglow and burst field from ROTSE-IIId is available at:
http://www.rotse.net/grb_reports/050525_btab.html
- GCN notice #3469
D. Malesani (SISSA), S. Piranomonte, F. Fiore (INAF/OARm), G.
Tagliaferri, D. Fugazza (INAF/OABr), and R. Cosentino (INAF/TNG), report
on behalf of a larger collaboration:
We imaged the field of the bright GRB 050525 (Band et al., GCN 3466;
Markwardt et al., GCN 3467) with the Italian 3.6m TNG. Observations were
performed under good observing conditions (seeing ~1.1"), even if close
to the bright Moon.
The object reported by Rykoff et al. (GCNs 3465, 3468) is clearly
detected in a single R-band image (2 min exposure) starting on 2005 Apr
25.07138 UT, 1.7 h after the GRB. Based on several nearby USNO stars,
its magnitude is R ~ 17.4. We thus confirm the fading behaviour of this
object.
This message can be cited.
- GCN notice #3470
K. Torii (Osaka U.) and Matt BenDaniel (http://Slooh.com) report:
"The error region of the bright GRB 050525 (Band et al. GCN 3466;
Markwardt et al. GCN 3467) was observed with the Slooh 14 inch f/6.3
telescope at Observatorio del Teide in the Canary Islands.
The observation started at 2005 May 25, 00:50 UT (47 minutes after
the burst) and a 30 s exposure in each of red, green, and blue filter
was obtained. We stacked the three frames and compared it with the DSS
frames.
As a result of the preliminary analysis, we note a 3.3-sigma
enhancement at position
(R.A., Dec.) = (18:32:32.65 +26:20:24.5) (J2000, 1.3" uncertainty)
with R~16.6 (USNO-A2.0 magnitude).
This is 8".4 away from the Swift XRT position (GCN 3466) while it agrees
with the refined position (Rykoff et al. GCN
3468) for the optical afterglow candidate (Rykoff et al. GCN 3465)."
- GCN notice #3471
J. Rosenberg (CfA) and P. Garnavich (Notre Dame)
We imaged the field of GRB 050525 (Band et al. GCN 3466)
and the optical afterglow reported by Rykoff et al. (GCN 3465)
with the 1.2m telescope of the Fred Whipple Observatory
and Stelircam infrared imager. Imaging in J and K' began
on May 25.22 (UT). Quick reduction of the K' data shows
a new source not visible in the 2MASS K image at 18:32:32.61
+26:20:22 +/-1.0" (J2000) based on the USNO A-2.0 catalog.
This is in agreement with the position provided by
Rykoff et al. (GCN 3468) and Torii & BenDaniel (GCN 3470)
given their quoted errors. The brightness is roughly K'=14.
This message may be cited.
- GCN notice #3472
D. Gotz, S. Mereghetti (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC,
Versoix), J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization
Team and N. Lund (DSRI, Copenhagen) on behalf of the ISWT report:
Offline analysis of the IBAS data showed that GRB 050525 discovered by
Swift (Band et al. GCN 3466, Markwardt et al. GCN 3467), has been detected
also by the IBIS/ISGRI instrument on board INTEGRAL.
The burst occurred at an off-axis angle of 14.7 degrees, very close to the
edge of the IBIS/ISGRI field of view, and illuminated through the coded
mask only 6% of the detector surface.
The preliminary value of the peak flux is 33 photons (3.2E-6 ergs)/cmsq/s
(1 sec integration time, 20-200 keV).
Owing to a small gap caused by telemetry saturation, we can only derive a
lower limit on the fluence of 144 photons (1.2E-5 ergs)/cmsq (12 s
integration time, 20-200 keV).
A plot of the multi peaed light curve is posted at:
http://ibas.mi.iasf.cnr.it/IBAS_Results.html
This message can be cited.
- GCN notice #3473
Klotz, A. (CESR-OMP), Boer M. (OHP), and Atteia, J.L. (LAT-OMP) report:
We imaged the entire field of GRB 050525 detected by SWIFT (Band et al. GCNC 3466)
with the TAROT robotic telescope (D=25cm) located at the Calern observatory,
France. Observations started at 00:08:52s UT, 4 seconds after the GCN notice,
and 6 min after the GRB. The field had an elevation of 62 degrees
above horizon at the begining of the observations.
The afterglow reported by Rykoff et al. (GCNC 3465) is clearly seen
in TAROT images, with a magnitude R=15.1, 6 minutes after the GRB,
and R=17.1, 108 minutes after the GRB. The unfiltered TAROT images are
calibrated relative to R-band magnitudes in the USNO A1 Catalog.
Further information, including a light-curve of the afterglow
during the first two hours after the GRB can be found at the following address:
http://www.cesr.fr/~klotz/grb050525/
This notice can be cited.
- GCN notice #3474
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:
A long bright GRB 050525 (Swift-BAT trigger=130088: GCN 3466,3467)
triggered Konus-Wind at 176.704 s UT (00:02:56.704).
As observed by Konus-Wind, it had a duration of ~11.5 s,
fluence (7.84 +/- 0.06)10-5 erg/cm2,
peak flux on 16-ms time scale (8.7 +/- 0.7)10-6 erg/cm2 s
(both in the 20 keV - 1 MeV energy range).
In ~2800 s after trigger, Konus-Wind detected
even more intense burst. Because it was detected
during data readout, only time history in the G2
window (74-295 keV) with 3-s time resolution is available.
It had a duration of ~20 s and fluence 25100 counts in
74-295 keV energy range (the fluence of the trigger burst
was 8500 counts in the same energy range). Assuming
it had the same spectrum as the trigger burst,
the energy fluence can be estimated as ~2.3x10^-4 erg/cm2.
Whether the second burst relates to the first one
or it is different GRB accidentaly registered close to
the trigger burst can be clarified by data
from other instruments
(but the chance to register two very bright bursts so close
to each other seems to be poor).
The time-integrated spectrum of the GRB 050525
is well fitted by a power law with
exponential roloff model:
dN/dE ~ E^alpha exp(-E/E0)
with alpha = -1.10 +/- 0.05,
and E0 = 93.6 +/- 5.3 keV.
The peak energy Ep = 84.1 +/- 1.7 keV.
- GCN notice #3475
S. Holland (GSFC), D. Band (GSFC/UMBC), A. Blustin,
S. Rosen (MSSL), P. Roming (PSU), P. Schady (MSSL/PSU),
K. Mason (MSSL), C. Gronwall (PSU), A. Breeveld (MSSL),
T. Poole, C. James, K. McGowan, M. de Pasquale (MSSL)
S. Hunsberger, C. Pagani, P. Brown, M. Ivanushkina (PSU),
B. Hancock, T. Kennedy (MSSL), P. Broos, S. Koch (PSU),
P. Smith, H. Huckle (MSSL), M. Still, P. Boyd,
W. Landsman (GSFC), J. Nousek (PSU), N. Gehrels (GSFC)
on behalf of the Swift UVOT team.
Swift/UVOT has detected GRB 050525 in all of its UV and
optical filters. Using data from 65 seconds after the
burst, we obtain the following magnitudes from images
summed between the T_start and T_stop times in the table:
Filter Magnitude Exp (s) T_start T_stop
V 14.97 +/- 0.02 287 65 1292
B 16.53 +/- 0.03 188 224 1084
U 15.32 +/- 0.03 98 90 979
UVW1 15.63 +/- 0.04 98 196 2046
UVM2 15.75 +/- 0.06 98 182 952
UVW2 16.62 +/- 0.05 188 952 1189
Where T_start and T_stop are in seconds after the
trigger (Band et al. GCN 3466).
The magnitudes are based on preliminary zero-points,
measured in orbit, and will require refinement with
further calibration.
- GCN notice #3476
J-L. Atteia & A. Pelangeon (LAT-OMP) report:
Taking into account the spectral parameters of GRB 050525
provided by Golenetskii et al. (GCNC 3474), we have computed
its pseudo-redshift, using the method described in Atteia, 2003, A&A, 407, L1.
We find a pseudo-redshift pz=0.36 +/- 0.1
We thank S. Golenetskii et al. for quickly providing
the spectral parameters of this GRB.
This notice can be cited.
- GCN notice #3477
S. Mereghetti, D. Gotz (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC,
Versoix), J. Borkowski (CAMK, Torun), A. von Kienlin, A. Rau, G. Lichti
(MPE, Garching) on behalf of the IBAS Team report:
The bright event seen by Konus/Wind about 2800 s after GRB 050525 and
reported in GCN 3474 (Golenetskii et al. 2005) has also been detected by
the Anti-Coincidence Shield of the SPI instrument on board INTEGRAL,
starting at 00:49:50 UT and lasting about 16 seconds.
At that time the position of GRB 050525A (GCN Circ. 3466, 3467, 3472) was
inside the field of view of the IBIS imaging instrument. No signal was
detected from this direction, indicating that the event at 00:49:50 UT is
not related with GRB 050525A and is most likely another bright GRB.
This message can be cited.
- GCN notice #3478
D. T. Durig (Cordell-Lorenz Observatory, University of the South), A. Oksanen
(Nyrola Observatory), C. Pullen (AAVSO) and A. Price (AAVSO) report on behalf of
the AAVSO International High Energy Network on optical observations of GRB050525
(GCN #3466; Band et al.):
An afterglow candidate is found at the location reported by Rykoff et al. (GCN
#3468) and Band et al. (GCN #3465). At 08:13 UT it is detected at an unfiltered
magnitude of 18-19 (fading over 100 mins centered on 08:13UT). The USNO star near
18 32 34.5 +26 20 24 can not completely be resolved from the afterglow candidate.
Full details and FITS image URL is below.
Name: Dr. Douglas T. Durig
email: ddurig@sewanee.edu
Observer: Dr. D. T. Durig ( CLW01)
Site: Cordell-Lorenz Observatory
Location: Sewanee, Tenn., USA
LatitudeLongitude: 35 12 N 85 55 W
Elevation: 600 m
Scope: SCT 0.30 m
ScopeFocalRatio: f/5.8 1765 mm
CCDVendor: SBIG STL-1001E
CCDDetector: KAF 1001E
CCDSize: 1024x1024
CCDPixelScale: 2.8
CCDFOV: 48x48 full, 12x12 quarter frame cropped
Object: GRB050525
ObsDate: 2005 05 25
ObsMidPointTime: 08 13 25
TimePerFrame: 120 sec
NumberOfFrames: 75
Filters: CR
Processing: dark, flat, register, co-add, 1/4 frame crop
Seeing: 5-6 arc sec
LimitingMag: 19.5-20 ???
Sky: very clear but breezy with Bright Moonlight
afterglowmag: 18-19
afterglowerr: 1
compstars: 1300 UCAC ref stars in full frame
Report: The USNO star near 18 32 34.5 +26 20 24 can not completely be resolved
from the afterglow candidate, but I do see it fade by around 1 mag over a little
over 100 min by summing a series of 30 consecutive 120 sec exposures. I get a
measured position of 18 32 33.9 +26 20 23 and 18 mag at 7:23 UT falling to 19 mag
at 9:03 UT, but this includes some contribution from the USNO star.
comments: UT dec.day CR mag
7:23:28 25.30796 18.0
7:40:09 25.31955 18.2
7:56:43 25.33105 18.3
8:13:25 25.34265 18.3
8:30:10 25.35428 18.3
8:46:49 25.36584 18.6
9:03:28 25.37741 19.0
A FITS image has been uploaded to
ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB050525_2453516.00275_.fits
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
- GCN notice #3479
J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC),
M. Chester (PSU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
F. Marshall (GSFC), T. Mitani (ISAS), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
M. Suzuki (Saitama), J. Tueller (GSFC),
on behalf of the Swift - BAT team:
At 00:02:53 UT Swift-BAT detected GRB 050525A (trigger=130088) (GCN
Circ 3466, Band, et al.). The refined BAT ground position is (RA,Dec)
= 278.140,+26.344, [deg; J2000] {18:32:34, +26:20:38} +- 0.5 arcmin,
(95% containment). This position is consistent with the reported
optical transient positions to within 20 arcsec (GCN Circ 3468,
Rykoff et al.; GCN Circ 3470, Torii et al.).
The image significance is 148 sigma, making GRB 050525 the most
significant BAT-imaged GRB to date. The burst was 26 degrees off
axis, and the partial coding fraction was 85%.
The mask-weighted light curve shows two peaks with duration of 2
and 5 seconds respectively. Each peak has two sub-pulses, which
become more distinct at higher energies. T90 is (8.8 +- 0.5) seconds
and T50 is (5.2 +- 0.5) seconds (15-350 keV; estimated errors include
systematics).
The spectrum has significant curvature, and is not consistent with a
single power law model. Fitting to a cut-off power law yields a
low-energy photon index of 1.0 +- 0.1, Epeak is 79 +- 4 keV. Fitting
to a "Band" GRB spectral model yields the same spectral parameters,
but the "beta" index is unconstrained. Chi2 for the Band model is
the same as for the cutoff power law. The fluence in the 15-350 keV
band is (2.0 +- 0.1) x 10^-5 erg/cm2. The 1-s peak photon flux,
starting at T0+1.63 second in the 15-350 keV band is (48 +- 1)
ph/cm2/s. All the quoted errors are at the 90% confidence level.
- GCN notice #3480
A. de Ugarte Postigo, M. Jelinek, J. Gorosabel, S. Guziy (IAA-CSIC
Granada),
P. Kubanek, R. Hudec (ASU-CAS, Ondrejov), S. Vitek (FEL-CVUT Praha),
T. J. Soria, R. Fernandez (EELM-CSIC Malaga), J. Fabregat (Univ. de
Valencia)
and A. J. Castro-Tirado(IAA-CSIC), report:
"The BOOTES-1 and BOOTES-2 very wide field cameras, located at INTA-
CEDEA (Huelva, Spain) and EELM-CSIC (Malaga, Spain) respectively, and
distant 200 km each other, observed the region of the sky containing the
SWIFT/BAT error box for GRB 050525 (Band et al. GCN 3466, Markwardt
et al. GCN 3467, Cummings et al. GCN 3469) as part of their routine
observing schedules. 30 s exposures started simultaneously at 00:03:00 UT
(7 s after the onset of the 10 s long burst), with the following frame
starting
at 00:04:00 UT (i.e. covering the late part of the event). A limiting
(unfiltered)
magnitude of 9.0 is derived for any prompt optical flash arising from this
particular GRB. Images are posted at:
http://www.iaa.es/~deugarte/GRBs/050525/GRB050525_wide.gif
- GCN notice #3481
Martin Jelinek (IAA CSIC Granada, Spain),
Petr Kubanek, Martin Nekola and Rene Hudec
(ASU AV CR Ondrejov, Czech Republic)
report:
The robotic telescope BART located at Astronomical Institute
in Ondrejov, Czech Republic, observed the errorbox of the
GRB050525 (Band et al. GCN 3466, Markwardt et al. GCN 3467,
Cummings et al. GCN 3469) with it's Wide-field camera. First
exposure started 18s after issuing the GCN alert (and 6m13s
after the GRB onset). Co-add of first ten minutes of
observation reveals the OT reported by Rykoff et al. (GCN
3468) at the detection limit of the image, which is V=15.5
according to our callibration made against GSC-1.2.
- GCN notice #3483
R. J. Foley (UCB), H.-W. Chen (MIT), J. Bloom (UCB), J. X. Prochaska
(UCSC) report:
"We obtained a 5x1800 sec dithered exposures of the optical candidate (GCN
3465) of GRB 050525 with GMOS on the Gemini-North telescope starting at
2005 May 25.43 UT. We measure a redshift of z = 0.606, which we assume to
be the redshift of the host galaxy, based on [O III] 5007 and H beta
emission and Ca H&K and Ca I 4228 absorption. There is perhaps very faint
[O II] emission. Further analysis is underway.
This notice may be cited."
- GCN notice #3484
J. Norris, S. Barthelmy, N. Gehrels (GSFC), J. Cummings (GSFC/NRC),
D. Band (GSFC/UMBC), L. Barbier (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), A. Parsons (GSFC), J. Tueller (GSFC)
Analysis of the Swift/BAT light curves, between channels
100-350 keV and 25-50 keV, yields an estimate of the spectral
lag of 0.124 +- 0.006 seconds for GRB 050525 (GCN 3466, Band
et al.; (GCN 3479, Cummings et al.).
Assuming the lag-luminosity relation (Norris et al. 2000, ApJ,
534, 248), using the Band model spectral parameters measured
during the 1-second peak of the burst's light curve --
alpha = -1.0, beta = -8.9, Epeak = 79 keV, and the 1-second
peak flux, 48 photon/cm^2/s, 15-350 keV --
we estimated a spectral-lag pseudo redshift of z = 0.72 +- 0.15,
in broad agreement with the spectroscopic redshift, z = 0.606,
reported by Foley et al. (GCN 3483).
Uncertainty in the high-energy spectral shape, and the difference
between the BATSE and BAT bandpass dependences of the lag-luminosity
relation on peak flux, combine to require the error of order
delta_z = 0.15.
- GCN notice #3485
P.A.Milne, G.G.Williams (Steward Obs), H.-S.Park (LLNL),
on behalf of the Super-LOTIS GRB team report:
We observed the field of GRB 050525 (SWIFT trigger 130088)
starting at UT=06:02:41 (05:59:48 after the burst),
with the 0.6m Super-LOTIS telescope at Kitt Peak, AZ.
We obtained 20 x 30-sec images in each of the R,V and I
filters. Observing conditions were affected by thin clouds
in addition to the bright moon.
Inspection of the three resulting co-added images reveals no source brighter
than our limitting magnitude at the location of the candidate
optical counterpart first reported by Rykoff et al. (GCN 3465,3468).
Comparisons were based upon the DSS2 image and the afterglow finders
provided by the ROTSE-III and TAROT collaborations.
We report upper limits of:
filter upper limit
R 06:16 17.5
V 06:47 17.5
I 07:18 18.0
These values can be compared with the unfiltered detections reported by
Durig et al. (GCN 3478).
The upper limits are based upon three stars in the USNOB catalog,
1163-0325237, 1163-0325216, 1163-0325240.
This message may be cited.
- GCN notice #3486
GRB 050525 : Lulin optical afterglow observations
P.S. Chiang (NCKU), K.Y. Huang, W.H. Ip (NCU), Y. Urata(RIKEN),
Y. Qiu (BAO), Y.Q. Lou (THCA) on behalf of EAFON report:
" We have imaged the GRB 050525 optical afterglow position reported by
Rykoff et al.(GCN 3468) and Torii et al. (GCN 3470) using 1.0-m
telescope at Lulin Observatory, Taiwan. The afterglow was detected at
LOT images. The R band magnitude of afterglow is about 21.3 +/-0.1
around 17.74 hours after burst ( exposure time 300sec x 4) which
compared with USNOB-1.0 stars.
Further analysis are in progress. This message may be
cited."
- GCN notice #3487
S.maeno,E.sonoda,Y.Tokunaga,M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error circle of
GRB 050525A (GCN3466 ; Swift BAT Trigger time is 00:02:53 UT)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 12:05:50 UT on May.25.
After co-adding a set of 73 images (12:05:50 - 14:26:49 UT)
of 30 sec exposures, we have compared with the USNO A2.0 catalog.
Preliminary analysis shows there is no new source brighter than
17.7 mag at the position reported by Rykoff et al.(GCN 3468)
and Torii et al.(GCN 3470)
- GCN notice #3488
N. Mirabal (U. Michigan), D. Bonfield and K. Schawinski (U. Oxford),
report on behalf of the MDM GRB follow-up team:
"Continuous r'-band photometry of the GRB 050525a afterglow (Rykoff et al.
GCN #3465) was obtained with the RETROCAM imager (Morgan et al.,
astro-ph/0502274) installed on the MDM 2.4m telescope. The data consists
of ~120 points spanning from 4.4 hr to 11.6 hr after the burst. During
this period, the magnitude of the optical afterglow is seen to decline
from R ~ 18.5 to R ~ 19.6, referenced to the R ~ 17.2 USNO star listed
by Rykoff et al. (GCN #3465). A fit to the latter part of the observations
yields a power-law decay slope of -1.38 +/- 0.2, consistent with a
tentative steepening of the decay after ~0.4 days. Further analysis is in
progress.
A graph of the preliminary differential magnitude light curve is available at
http://www-personal.umich.edu/~mirabal/grb050525/lightc.ps"
- GCN notice #3489
K. Yanagisawa (OAO/NAOJ), H. Toda, and N. Kawai (Tokyo Tech) report on
behalf of the MITSuME collaboration:
"We observed the field of GRB 050525 (Band et al.; GCN 3466) with the
3-color MITSuME 50cm Telescope at Okayama, Japan starting at 12:03(UT)
on May 25, 2005. We obtained a 5400 sec exposure (120 sec x 45 frames;
midtime=13:02 UT) simultaneously in V, R, and I-bands. We confirmed
the optical afterglow (Rykoff et al.; GCN 3465) in R and I bands at
the position
RA=18:32:32.6, DEC=+26:20:22 (J2000)
with magnitudes R = 19.30 +/- 0.17 and I = 20.12 +/- 0.29. We did not
detect the optical transient in the V-band image with an upper limit
of V=19.2."
- GCN notice #3491
Autumn Homewood, Dieter H. Hartmann, Kiran Garimella (Clemson Univ.), Gary
Henson (ETSU), Jeremy McLaughlin (Radford Univ.), Adam Brimeyer (Iowa
State Univ.) report:
We observed a 6x6 arcminute field centered on the optical afterglow of GRB
050525a (GCN 3466), identified by ROTSE-IIIc (GCN 3465) with the SARA 0.9
m Telescope at KPNO. Observations were carried out under good seeing
conditions with the AP7 CCD. We obtained 35 300-second exposures each in
the R-band, in 2 seperate groups. Observations of the first group (27
images) started at UT 2005/05/25 04:40:15, and ended 07:08:07.
Observations of the second group (8 images) began at UT 10:51:29, and
ended at 11:33:59. At the beginning of the first observation run we detect
the afterglow at R = 18.9 +/- 0.2 mag, relative to USNO B2.0 R1.
The SARA home page can be found at
http://www.astro.fit.edu/sara/sara.html
This message may be cited.
- GCN notice #3492
V.Rumyantsev (CrAO), G. Kornienko, A. Erofeeva, (UAPhO), A.Pozanenko (IKI)
on behalf of larger GRB follow up collaboration report:
We have observed the refined error box (Cummings et al., GCN 3449) of the
Swift GRB050525a (Band et al., GCN 3466) with 0.4m telescope of Ussuriysk
Astrophysical Observatory (UAPhO), and AT-64 telescope of CrAO on May, 25.
We do not detect OT found by Rykoff et al., (GCN 3465). Upper limits of
unfiltered stacked images calibrated against of R USNO-A2.0 are following:
Mean time Exposure Limiting mag.
May 25
(UT) (s)
13:59 7x60 15.9
19:38 40x60 19.5
The message may be cited.
- GCN notice #3493
Z. Aslan, I. Khamitov, T. Ozisik, K. Uluc (TUG), U. Kiziloglu (METU),
I. Bikmaev, N. Sakhibullin (KSU/AST), A. Alpar (SabUni),
A.Yaskovich, R.Burenin, M. Pavlinsky, R. Sunyaev (IKI),
report:
We have observed the field of OT of GRB 050525 (Rykoff et al, GCN3465)
with 2k*2k Andor CCD attached to the Russian-Turkish 1.5-m telescope
(Bakirlitepe, Turkey) in VRc bands.
We made series of 5*90s exposures in V, starting at 00:22UT May 26,
and 20*60s exposures in Rc, starting at 01:18 UT May 26.
On 20 co-added R-images we clearly see the OT at the position
RA = 18:32:32.57 (2000.0), DEC=+26:20:22.5 (2000.0)
based on the USNO-B1 catalog, its uncertainty is about 0.1 arcsec.
We estimate m_R magnitude of OT using USNO-B1 as 21.76+/-0.17
corresponding to the midtime of 25.5 hours after the burst.
This message may be cited.
- GCN notice #3495
P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of
the Caltech-NRAO-Carnegie GRB Collaboration:
"We observed the field of GRB050525a (GCN#3466) using the Very Large Array
at a frequency of 22.5 GHz on May 25.42 UT and May 26.36 UT. We detect a
radio source at the position of the optical transient (GCN#3468)."
- GCN notice #3506
B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS
consortium, report:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained simultaneous optical/IR imaging of the error region of
GRB 050525a (Band et al. GCN 3466). Several dithered images were obtained
in each filter, with total summed exposure times of 180s in each of BRIYJK
and 120s in each of H and V. Imaging was carried out in a symmetrical
manner so that the mid-exposure time is the same for all final combined
images, in this case being ~5.2 hours post-burst (2005-05-25 05:13 UT).
The afterglow reported by Rykoff et al. (GCNs 3465, 3468) is detected in
each summed image, though the source appears only slightly above the
background. Preliminary comparison with USNO B1.0 stars in the optical
and 2MASS stars in the IR yields the following approximate afterglow magnitudes:
filter AG mag
------ ------
B 18.8+/-0.4
R 18.1+/-0.3
I 18.8+/-0.3
J 17.4+/-0.3
H 16.6+/-0.3
K 16.15+/-0.35
Furthermore, a second epoch of imaging was obtained at a mid-exposure time
of ~53.4 hours post-burst (2005-05-27 05:27 UT). Total summed exposure
times for these images was 36 min in I and 30 min in J. The afterglow
experienced significant decay between epochs and is not detectable in the
second epoch images to a limiting magnitude of I > 21.2+/-0.2
and J > 18.8+/-0.1.
- GCN notice #3507
D. Kaplan (MIT), P. Garnavich (Notre Dame), J. Rosenberg (CfA)
and K.Z. Stanek (CfA, Ohio State)
The field of GRB 050525a (Band et al. GCN 3466) was imaged
with the PANIC infrared camera on the Baade telescope of the
Magellan Observatory on May 26 and 27 (UT) and we detect the
afterglow (Rykoff et al. GCN 3465;3468) in the Ks-band on
both nights. Using the 2MASS calibrated stars in the field
we find the afterglow on May 26.278 (UT) to have Ks=19.2+/-0.1.
We also have properly calibrated the FLWO observation obtained
on May 25 (Rosenberg & Garnavich GCN 3471) and combined all three
nights of data. We find that the afterglow light curve in the
K-band is well represented by a power-law decay with a slope
of -1.6 and Ks=18.75 one day after the burst.
This message may be cited.
- GCN notice #3532
P. Garnavich (Notre Dame), M. Pahre (CfA), A. Noriega-Crespo (CalTech),
K.Z. Stanek (CfA, OSU), S.T. Holland (GSFC), D. Bersier (STScI),
T. Matheson (NOAO), R. Perna (U. Colorado), K. Krisciunas (Notre Dame)
After confirmation of a bright optical afterglow associated with
GRB 050525 (Band et al. GCN 3466; Rykoff et al. GCN 3465;3468) we
triggered a "target-of-opportunity" (ToO) program on the Spitzer Space
Telescope. Observations began on May 27.26 (UT), or 2.26 days
after the burst, with IRAC imaging followed by IRS spectroscopy,
MIPS mapping and finally another epoch of IRAC images ending on
May 27.56 (UT).
Soon after triggering the ToO, the brightness of the afterglow
switched to a steeper decline rate (Mirabal et al. GCN 3488;
Kaplan et al. GCN 3507) making a rapid response essential.
The first epoch of imaging shows point source at the position of the
afterglow (Rykoff et al. GCN 3468; Yanagisawa et al. GCN 3489)
in the 3.6,4.5 and 8.0 micron IRAC channels and in the 24 micron
MIPS band.
A second epoch of IRAC imaging and MIPS mapping was performed
on May 29. The source is seen to fade in IRAC between the two
epochs of the first visit and is beyond the detection limit
during the second visit. The MIPS 24 micron source is also
seen to fade between visits.
This is the first confirmed detection of a GRB afterglow at
mid-infrared wavelengths. Preliminary estimate of the flux in
the IRAC channels combined with K-band observations of Kaplan et al.
(GCN 3507) suggests a spectral energy distribution consistent
with a power-law. The index of the power-law between 2 and 8 microns
is 1.3+/-0.2. This is surprisingly steep and further analysis
is continuing.
The IRAC 3.6 micron images taken at two epochs can be viewed at:
http://www.nd.edu/~pgarnavi/grb050525/irac.jpg
We thank Nancy Silbermann and the Spitzer Science Center for
rapidly responding to a complex target-of-opportunity observation.
This message may be cited.
- GCN notice #3550
A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie
collaboration:
"We observed the field of GRB050525a (GCN 3466) with HST+ACS/WFC on 12 Jun
2005 UT (t~18 days) as part of our HST Cycle 13 program to study the
supernovae associated with gamma-ray bursts and X-ray flashes (GO 10135;
PI Kulkarni). Coincident with the afterglow position (GCN 3468), we
detect a point source superposed on top of a compact galaxy. Within a 0.5
arcsec aperture, we find the host+OT system to be F625W ~ 24.2 mag (Vega).
Adopting this value as a limit on the brightness of an associated
supernova, we find that the SN associated with GRB050525a is at least ~0.6
magnitudes fainter than SN1998bw at a comparable epoch (assuming
negligible host extinction). Further observations are planned."
- GCN notice #3551
GRB 050525A: Swift Late-Time Decay Rate
S. T. Holland, (GSFC/USRA), D. Band (GXFC), A. Blustin (MSSL), P. Boyd
(GSFC/UMBC), F. Marshall (GSFC), K. Mason (MSSL), M. Perri (ASI),
A. Breeveld (MSSL), P. Brown, A. Cucchiara, C. Gronwall, S.
Hunsberger, M. Ivanushkina (PSU), W. Landsman (GSFC), K. McGowan
(MSSL), A. Morgan (PSU), M. De Pasquale, T. Poole (MSSL), P. Roming
(PSU), S. Rosen, (MSSL), P. Schady (MSSL), M. Still (GSFC/USRA),
J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team
report:
Swift/UVOT data suggest that there is a jet break at 17,979 s
(0.205 d) after the BAT trigger (Band et al. 2005, GCN 3466) in the
optical/ultraviolet afterglow of GRB 050525A. The observed decay
index after the jet break is -1.73. The Swift/XRT data also show a
late-time break followed by a steep power-law decay. If we
extrapolate the UVOT late-time decay to the time of the HST F625W
observation (Soderberg 2005, GCN 3550) the predicted magnitude of the
optical afterglow is approximately V = 27.4. Therefore the HST
observations suggest that the optical afterglow of GRB 050525A was
approximately three magnitudes brighter at 18 days after the burst
than expected from the fireball model alone. More data are needed to
determine if this additional luminosity is due to a host galaxy or
some form of rebrightening such as a supernova or a dust echo.
- GCN notice #3566
M. Nysewander (North Carolina), J. Flasher (Colorado), F. Hearty
(Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q.
Lamb (Chicago), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO),
B. Ketzeback (APO), D. Reichart (North Carolina), and D. G. York (Chicago)
report on behalf of the FUN GRB collaboration:
Using griz all-sky photometry of a 4.8 arcmin x 4.8 arcminute field
centered on the coordinates of the optical afterglow of GRB 0505025a that
was derived from ARC 3.5-meter SPIcam observations made between 4:00 and
7:00 UT on 2005 June 13, we have calculated the griz magnitudes of 103
sources in the field of GRB 050525a:
http://www.physics.unc.edu/~mnysewan/grb050525a.dat
The astrometry in these files is based on the USNO B1.0-catalogue. The
estimated systematic errors in the astrometry are less than 400mas. The
estimated systematic photometric errors are typically =B1 0.05 mag in the
gri bands and =B1 0.06 mag in the z band.
- GCN notice #3567
GRB 050525a: ARC 3.5-meter Optical and NIR Observations
J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow
(Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), D. G. York
(Chicago), G. Wallerstein (Washington), V. Woolf (Washington), S.
Anderson (Washington), J. Dembicky (APO), J. Barentine (APO), R.
McMillan (APO), and B. Ketzeback (APO) report on behalf of the ARC GRB
team of the FUN GRB collaboration:
We observed the afterglow (Rykoff et al., GCN Circular No. 3465;
Malesani et al., GCN Circular No. 3469) of GRB 050525a, a burst
localized by Swift/BAT (Band et al., GCN Circular No. 3466; Markwardt
et al., GCN Circular No. 3467), on the night of May 24th, using SPIcam
and NIC-FPS on the ARC 3.5-meter telescope at Apache Point
Observatory. The observation began at 08.33 UT on 25 May 2005 (8.28
hours after the burst) and ended at 11.07 UT on 25 May 2005 (11.02
hours after the burst). The observation consisted of two 300-second
exposures each in r, i, and z; and a series of 60-, 60-, 10-, and
10-second exposures in Z, J, H, and Ks, respectively. We have
constructed stacked images of the GRB field, corresponding to 10-minute
integrations in r, i, z, and Z; and 20-minute integrations in J, H, and
Ks. We detect the afterglow in all seven filters, and measure J =3D 18.3
=B1 0.1 at 09:50 UT (the mid-point time of the J-band observation),
calibrated relative to the 2MASS stars in the field.
NIC-FPS is currently in its commissioning phase.
This message may be cited.
- GCN notice #3568
This is a multi-part message in MIME format.
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Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
J. Haislip, C. MacLeod, M. Nysewander, A. Foster, J. A. Crain, D.
Reichart,
M. Bayliss, J. Kirschbrown, and C. Mack report on behalf of the UNC team
of
the FUN GRB Collaboration:
We observed the BAT localization of GRB 050525a (Band et al., GCN 3466)
with PROMPT-5 beginning 5.3 hours after the burst. We detect the
afterglow
(Rykoff et al., GCN 3465) in VRcIc across multiple epochs.
Using the field calibration of Nysewander et al. (GCN 3566), we find =
that
Rc =3D 19.84 +/- 0.11 mag at a mean time of 8.1 hours after the burst.
PROMPT is still being built and commissioned.
- GCN notice #3660
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:
In GCN 3474 we reported wrong value of the Konus-Wind fluence
for GRB 050525A (because of missprinting).
The correct value is (2.06 +/- 0.02)10-5 erg/cm2 .
The reported peak flux and spectral parameters were correct.
We thank Dr. Hurley for noticing this error.
- GCN notice #3721
J-L. Atteia & A. Pelangeon (LAT-OMP) report:
Taking into account the revised value of the fluence of GRB 050525a provided
by Golenetskii et al. in GCN 3660, we have re-computed the pseudo-redshift of
GRB 050525a (using the method described in Atteia, 2003, A&A, 407, L1).
We find a pseudo-redshift pz=0.64 +/- 0.1, in good agreement with the
spectroscopic redshift z=0.606
- GCN notice #3855
A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team:
We have acquired BVRcIc all-sky photometry for 23x23arcmin
fields centered on the coordinates of recent GRB localizations
with the USNOFS 1.0-m telescope on 1 or 2 photometric nights
but with bright moonlight and variable seeing. Stars brighter
than V=12.0 are saturated and should be used with care. We have
placed the photometric data on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050525.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050607.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050802.dat
The astrometry in these files is based on linear plate solutions
with respect to UCAC2 or USNO-A2.0. The external errors are usually
200mas or better. The estimated external photometric error is
about 0.03mag. Some fields are relatively crowded, and the
large apertures required to handle the variable seeing also
blended some measurements, so choose comparison stars wisely.
We have one additional night for GRB050525 that will be
added when reductions are complete.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry. There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.
- astro-ph/0604109 from 5 Apr 2006
Valle: Hypernova Signatures in the Late Rebrightening of GRB 050525A
We report observations of GRB 050525A, for which a Gemini North spectrum
shows its redshift to be z = 0.606. This is the third closest long GRB
discovered by Swift. We observed its afterglow using the VLT, Gemini and TNG
telescopes to search for an associated SN. We find that the early-time light
curve is described by a broken power law with a break at t ~ 0.3 d after the
burst. About 5 d after the burst, a flattening is apparent, followed by a
further dimming. Both the magnitude and the shape of the light curve suggest
that a supernova was emerging during the late decay of the afterglow. This
supernova, dubbed SN 2005nc, had a rise time faster than SN 1998bw and a
long-lasting maximum. A spectrum obtained about 20 d (rest-frame) after the GRB
resembles the spectrum of SN 1998bw obtained close to maximum light.
- 1109.4717 from 23 Sep 11
Peter-Christian Zinn et al.: Supernovae without host galaxy? - Hypervelocity stars in foreign galaxies
Harvesting the SAI supernova catalog, we search for SNe that apparently do not occur within a distinct host galaxy but lie a great distance
apart from their assigned host galaxy. Assuming two possible explanations for this host-lessness of a fraction of reported SNe, namely (i) a
host galaxy which is too faint to be detected within the limits of currently available surveys or (ii) a hypervelocity star (HVS) as progenitor
of the SN,we want to distinguish between these two cases. To do so, we use deep imaging to test explanation (i). If within our detection limit
of 27 mag/arcsec^2, the central surface brightness of the faintest known LSB galaxy so far, no galaxy could be identified, we discard this
explanation and regard the SN, after several other checks, to have had a hypervelocity star progenitor. Analyzing a selected subsample of five
host-less SNe we find one, SN 2006bx in UGC5434, to be put in the hypervelocity progenitor category with a high probability, exhibiting a
projected velocity of > 800 km/s. SN 1969L in NGC1058 is most likely an example for a very extended star-forming disk visible only in the
far-UV, not in the optical wavebands. Therefore this SN is clearly due to in situ star formation. This mechanism may also apply for two other
SNe we investigated (SN 1970L and SN 1997C), but this cannot be determined with final certainty. Another one, SN 2005nc associated with a
gamma-ray burst (GRB 050525), is a special case not covered by our initial assumptions. Even with deep Hubble data, a host galaxy could not be
unambiguously identified.
- 1207.3003 from 13 Jul 12
L. Resmi et al.: Comprehensive multi-wavelength modelling of the afterglow of GRB050525A
The Swift era has posed a challenge to the standard blast-wave model of Gamma Ray Burst (GRB) afterglows. The key observational features
expected within the model are rarely observed, such as the achromatic steepening (`jet-break') of the light curves. The observed afterglow
light curves showcase additional complex features requiring modifications within the standard model. Here we present optical/NIR observations,
millimeter upper limits and comprehensive broadband modelling of the afterglow of the bright GRB 0505025A, detected by Swift. This afterglow
cannot be explained by the simplistic form of the standard blast-wave model. We attempt modelling the multi-wavelength light curves using (i) a
forward-reverse shock model, (ii) a two-component outflow model and (iii) blast-wave model with a wind termination shock. The forward-reverse
shock model cannot explain the evolution of the afterglow. The two component model is able to explain the average behaviour of the afterglow
very well but cannot reproduce the fluctuations in the early X-ray light curve. The wind termination shock model reproduces the early light
curves well but deviates from the global behaviour of the late-time afterglow.
- 1307.1177 from 5 Jul 13
Camilo Delgado-Correal: Study of shock wave dynamics produced by interaction
of a fireball with the surrounding medium to it, to explain the x-ray
afterglow of Gamma Ray Burst-GRBs >BR>
The Gamma-Ray Bursts - GRBs are one of the most energetic astronomical events in the universe that have not yet an adequate explanation of what
kind of mechanism is carried out. This question motivates the astronomical community to do radiation measurements associated with the GRBs.
They also are doing physical models to explain the temporal behavior of these observational results. The community are looking for an
appropriate explanation of GRBs origin.
This thesis presents an astrophysical model that includes an hydrodynamic and radiative aspects. This model studies the temporal evolution of a
wave carries an expansive ultra-relativistic adiabatic fluid. Additionally, this thesis present a comparison between model with GRB 050525
observational behavior. It is found that the blast wave radius R shows an increase in the time: R \approx t^{1/4}, the Lorentz gamma factor of
charged particles that are in ultra-relativistic fluid decreases significantly over time and the theoretical flow of radiation: F_{\nu} \approx
t^{-\beta} with {\beta} around 1 fits very well with the two slopes of the x-ray afterglow light curve of GRB 050525.
Previous IAU Circulars 
