| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB090422150 |
|
| T0 |
3:35:16 UTC |
GCN_circulars,Swift Det |
| ra |
294.7496° |
Swift |
| decl |
40.3842° |
Swift |
| pos_error |
1.81e-04° |
Swift |
| T90 |
9.216 s |
Fermi_GBM |
| T90_error |
0.362 s |
Fermi_GBM |
| T90_start |
3:35:16.555 UTC |
Fermi_GBM |
| fluence |
4.59e-07 erg/cm² |
Fermi_GBM |
| fluence_error |
3.44e-08 erg/cm² |
Fermi_GBM |
| T100 |
9.771 s |
|
| GBM_located |
False |
|
| mjd |
54943.14949074074 |
GCN_circulars,Swift Det |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB090422150 |
| trigger_name |
bn090422150 |
| ra |
294.7000° |
| decl |
40.4000° |
| datum |
2009-04-22 |
| t_trigger |
3:35:17.067 UTC |
| T90 |
9.216 s |
| T90_error |
0.362 s |
| T90_start |
3:35:16.555 UTC |
| fluence |
4.59e-07 erg/cm² |
| fluence_error |
3.44e-08 erg/cm² |
| flux_1024 |
2.37e+00 erg/cm²/s |
| flux_1024_error |
2.39e-01 erg/cm²/s |
| flux_1024_time |
-7.04e-01 erg/cm²/s |
| flux_64 |
4.94e+00 erg/cm²/s |
| flux_64_error |
1.31e+00 erg/cm²/s |
| IPN table |
|---|
| GRB_name |
GRB090422A |
| ra |
294.7542° |
| decl |
40.3833° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB090422A |
| t_trigger |
3:35:16 UTC |
| ra |
294.7496° |
| decl |
40.3842° |
| pos_error |
1.81e-04° |
| T90 |
8.5 s |
| fluence |
2.30e-07 erg/cm² |
| GCN 9185 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9185 |
| Detection_method |
Swift Det |
| t_trigger |
3:35:16 UTC |
| ra |
294.7560° |
| decl |
40.3840° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9185
SUBJECT: GRB 090422: Swift detection of a burst
DATE: 09/04/22 03:51:57 GMT
FROM: Scott Barthelmy at NASA/GSFC
T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), D. M. Palmer (LANL),
M. Perri (ASDC), G. Stratta (ASDC) and L. Vetere (PSU) report on
behalf of the Swift Team:
At 03:35:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090422 (trigger=349931). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 294.756, +40.384 which is
RA(J2000) = 19h 39m 01s
Dec(J2000) = +40d 23' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows two spikes
with a total duration of about 10 sec. The peak count rate
was ~3500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 03:36:20.6 UT, 64.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 294.74931,
40.38530 which is equivalent to:
RA(J2000) = 19h 38m 59.83s
Dec(J2000) = +40d 23' 07.1"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 18 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 consistent with the Galactic value of
1.65e+21 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 5.51e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 74 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 coverage of the XRT error circle by the 8'x8' region for the list of
sources generated on-board is uncertain because the large number of sources
filled the available telemetry. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.20.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com).
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 9187 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9187 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9187
SUBJECT: GRB 090422: Liverpool Telescope observations
DATE: 09/04/22 10:19:52 GMT
FROM: Cristiano Guidorzi at Ferrara U,Italy
C. Guidorzi (U. Ferrara), D. Bersier, A. Melandri, C.J. Mottram,
C.G. Mundell, R.J. Smith, I.A. Steele (Liverpool JMU) on behalf of
a large collaboration report:
On 2009 April 22 at 03:37:40 UT the 2-m Liverpool Telescope robotically
reacted and began observing the Swift GRB 090422 (Ukwatta et al.,
GCN Circ. 9185) using the r',i', and z' filters, corresponding to
2.40 min after the BAT trigger time.
Inside the revised XRT error circle we detect a single object of
r' ~ 19 mag, which is already present in the DSS archive images and
shows no significant fading from 10 min to 1 hr post burst.
|
| GCN 9194 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9194 |
| Detection_method |
Swift-XRT Det |
| ra |
294.7497° |
| decl |
40.3845° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9194
SUBJECT: GRB 090422: Enhanced Swift-XRT position
DATE: 09/04/22 16:44:16 GMT
FROM: Phil Evans at U of Leicester
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 6291 s of XRT Photon Counting mode data and 8 UVOT
images for GRB 090422, 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 = 294.74967, +40.38445 which is equivalent
to:
RA (J2000): 19h 38m 59.92s
Dec (J2000): +40d 23' 04.0"
with an uncertainty of 1.5 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 9195 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9195 |
| Detection_method |
Swift-BAT Det |
| ra |
294.7460° |
| decl |
40.3980° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9195
SUBJECT: GRB 090422: Swift-BAT refined analysis
DATE: 09/04/22 17:39:45 GMT
FROM: Scott Barthelmy at NASA/GSFC
C. B. Markwardt (GSFC/UMD), 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), 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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090422 (trigger #349931)
(Ukwatta, et al., GCN Circ. 9185). The BAT ground-calculated position is
RA, Dec = 294.746, 40.398 deg which is
RA(J2000) = 19h 38m 59.1s
Dec(J2000) = +40d 23' 52.1"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 72%.
The mask-weighted light curve shows two main peaks at T0 and T+8 sec.
They are each about 1 sec wide. There is a third, weaker peat at ~T=50 sec.
T90 (15-350 keV) is 8.5 +- 0.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.4 to T+8.5 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.72 +- 0.30. The fluence in the 15-150 keV band is 2.3 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.37 sec in the 15-150 keV band
is 1.7 +- 0.2 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/349931/BA/
|
| GCN 9197 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9197 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9197
SUBJECT: GRB 090422: Liverpool Telescope possible candidate
DATE: 09/04/23 00:12:49 GMT
FROM: Cristiano Guidorzi at Ferrara U,Italy
C. Guidorzi (U. Ferrara), D. Bersier, C.G. Mundell (Liverpool JMU)
on behalf of a large collaboration report:
Following the distribution of the enhanced Swift-XRT position
(Beardmore et al. GCN Circ. 9194) of GRB 090422 (Ukwatta et al.
GCN Circ. 9185), we re-analysed the data acquired with the
Liverpool Telescope, mentioned in our previous report
(Guidorzi et al. GCN Circ. 9187).
Inside the enhanced XRT error circle we detect a single object
with magnitude of (21.7 +/- 0.3) in the r' filter, from 11 to 43
min post burst, at the following position (J2000):
RA= 19:38:59.91
Decl= +40:23:03.5
with an uncertainty of 0.7 arcsec. The calibration was done with
respect to nearby USNOB-1 stars, using the R2 magnitudes values.
This source is also detected in i' and z' filters.
At the moment we cannot assess whether the object is fading.
The source of r'~19 mag mentioned in our earlier report lies
outside the enhanced XRT error circle.
Further observations are planned.
|
| GCN 9203 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9203 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9203
SUBJECT: GRB 090422: Swift/UVOT Upper Limits
DATE: 09/04/23 11:37:54 GMT
FROM: Alice Breeveld at MSSL-UCL
A. A. Breeveld (MSSL/UCL) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 090422 starting 55 s
after the BAT trigger (Ukwatta, et al., 2009, GCN Circ. 9185). Settled
exposures started at T+74 s with a Finding Chart (FC) in the white
filter. We do not find any new source, at the enhanced position of the
XRT afterglow (Beardmore, et al. 2009, GCN Circ. 9194) nor at the
position of the candidate found by the Liverpool Telescope (Guidorzi,
et al. 2009, GCN Circ. 9197). 3-sigma upper limits for detecting a
source in the white and u FCs, and subsequent co-added images in all
filters are:
Filter T_start T_stop Exp(s) Mag
----------------------------------------------------------
white (FC) 74 224 147 >20.5
u (FC) 287 537 246 >19.6
v 617 11744 1317 >20.3
b 542 18318 1145 >20.8
u 690 24099 2059 >20.8
uvw1 666 23300 2203 >21.0
uvm2 641 22393 2092 >20.8
uvw2 592 10831 1318 >20.8
white 566 5591 341.4 >20.8
---------------------------------------------------------
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} = 0.198 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 9208 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9208 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9208
SUBJECT: GRB 090422: Swift-XRT refined analysis
DATE: 09/04/23 14:58:43 GMT
FROM: Matteo Perri at ISAC/ASDC
M. Perri and G. Stratta (ASDC) report on behalf of the Swift-XRT Team:
We have analysed the first 31 ks of Swift-XRT data obtained from
GRB 090422 (trigger 349931; Ukwatta et al., GCN Circ. 9185), starting
from T+70 s and ending at T+70 ks.
The best position of the X-ray afterglow is the UVOT-enhanced XRT
position given in Beardmore et al. (GCN Circ. 9194).
The 0.3-10 keV X-ray light curve is well described by a double broken
power-law model with decay indices alpha1=-1.7+/-0.2, alpha2=-0.2+/-0.3,
alpha3=-1.0+/-0.1 and temporal breaks t1=421+/-92 s and t2=1.5+/-0.3 ks .
The X-ray spectrum is well fit by an absorbed power-law model with a
photon index of 2.5+/-0.2 and a column density of (2.3+/-0.7)e21 cm**-2
in excess to the Galactic one in the direction of the source
(1.7e21 cm**-2, Kalberla et al. 2005). The count-rate to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.6(8.7)E-11 erg cm**-2 count**-1.
Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of 2e-3 count/s at T+48hr, which
corresponds to an observed 0.3-10 keV flux of ~7e-14 erg/cm**2/s.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00349931.
This circular is an official product of the Swift-XRT team.
|
| GCN 9228 table |
|---|
| GRB_name |
GRB090422A |
| GCN_number |
9228 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
3:35:17.070 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9228
SUBJECT: GRB 090422: Fermi GBM observation
DATE: 09/04/24 15:57:39 GMT
FROM: Sheila McBreen at MPE
Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:
"At 03:35:17.07 UT on 22 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090422 (trigger 262064119 / 090422150)
which was also detected by the Swift-BAT (Ukwatta et al. 2009, GCN 9185
& Markwardt et al. 2009, GCN 9195). The GBM on-ground location is
consistent with the Swift position.
The angle from the Fermi LAT boresight is 29 degrees.
The GBM light curve consists of 2 pulses
with a duration (T90) of about 10 s (8-1000 keV).
The time-averaged spectrum from T0-2.4 s to T0+10.8 s is
adequately fit by a simple power law function with
index 1.81 +/- 0.15 (chi squared 358 for 361 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(1.0 +/- 0.1)E-6 erg/cm^2. The 0.128 sec peak photon flux measured
starting from T0-0.256 s in the 8-1000 keV band
is 7.8 +/- 0.5 ph/s/cm^2.
|