| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB220618382 |
|
| T0 |
9:10:19.075 UTC |
Fermi_GBM |
| ra |
38.9860° |
Swift |
| decl |
55.2155° |
Swift |
| pos_error |
2.59e-04° |
Swift |
| T90 |
43.777 s |
Fermi_GBM |
| T90_error |
8.464 s |
Fermi_GBM |
| T90_start |
9:10:19.075 UTC |
Fermi_GBM |
| fluence |
3.38e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
4.99e-08 erg/cm² |
Fermi_GBM |
| T100 |
105.925 s |
|
| GBM_located |
False |
|
| mjd |
59748.382165219904 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB220618382 |
| trigger_name |
bn220618382 |
| ra |
23.0100° |
| decl |
55.8400° |
| pos_error |
5.49e+00° |
| datum |
2022-06-18 |
| t_trigger |
9:10:19.587 UTC |
| T90 |
43.777 s |
| T90_error |
8.464 s |
| T90_start |
9:10:19.075 UTC |
| fluence |
3.38e-06 erg/cm² |
| fluence_error |
4.99e-08 erg/cm² |
| flux_1024 |
2.31e+00 erg/cm²/s |
| flux_1024_error |
2.10e-01 erg/cm²/s |
| flux_1024_time |
1.00e+01 erg/cm²/s |
| flux_64 |
3.82e+00 erg/cm²/s |
| flux_64_error |
1.04e+00 erg/cm²/s |
| IPN table |
|---|
| GRB_name |
GRB220618A |
| ra |
38.9667° |
| decl |
55.2167° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB220618A |
| t_trigger |
9:10:29 UTC |
| ra |
38.9860° |
| decl |
55.2155° |
| pos_error |
2.59e-04° |
| T90 |
96.0 s |
| fluence |
2.20e-06 erg/cm² |
| GCN 32214 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32214 |
| Detection_method |
Swift Det |
| t_trigger |
9:10:29 UTC |
| ra |
38.9660° |
| decl |
55.2140° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32214
SUBJECT: GRB 220618A: Swift detection of a burst
DATE: 22/06/18 09:25:56 GMT
FROM: Kim Page at U.of Leicester
E. Troja (NASA/GSFC/UMCP), C. Gronwall (PSU), K. L. Page (U Leicester)
and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 09:10:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220618A (trigger=1110821). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 38.966, +55.214 which is
RA(J2000) = 02h 35m 52s
Dec(J2000) = +55d 12' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single peak
structure with a duration of about 40 sec. The peak count rate
was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 09:12:53.1 UT, 143.2 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 38.98802, 55.21543
which is equivalent to:
RA(J2000) = 02h 35m 57.12s
Dec(J2000) = +55d 12' 55.5"
with an uncertainty of 4.3 arcseconds (radius, 90% containment). This
location is 45 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 https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (4.74 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 8.9
(+7.86/-6.18) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 6.79e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 151 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 large, but uncertain, extinction expected.
Burst Advocate for this burst is E. Troja (nora.gsfc 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/)
|
| GCN 32216 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32216 |
| Detection_method |
Swift-XRT Det |
| ra |
38.9860° |
| decl |
55.2157° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32216
SUBJECT: GRB 220618A: Enhanced Swift-XRT position
DATE: 22/06/18 13:14:20 GMT
FROM: Phil Evans at U of Leicester
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 345 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 220618A, 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 = 38.98602, +55.21568 which is equivalent
to:
RA (J2000): 02h 35m 56.65s
Dec (J2000): +55d 12' 56.4"
with an uncertainty of 2.2 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, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
|
| GCN 32218 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32218 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32218
SUBJECT: GRB 220618A: Swift/UVOT Upper Limits
DATE: 22/06/18 15:40:50 GMT
FROM: Paul Kuin at MSSL
N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220618A
151 s after the BAT trigger (Troja et al., GCN Circ. 32214).
No optical afterglow consistent with the XRT position (Troja et al. GCN
Circ. 32214) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 151 301 147 >19.8
u_FC 309 559 246 >18.9
white 151 609 167 >19.8
v 641 649 8 >17.4
b 565 585 19 >17.9
u 309 559 246 >18.9
w2 617 637 19 >18.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.391 in the direction of the burst
(Schlegel et al. 1998).
|
| GCN 32219 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32219 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32219
SUBJECT: GRB 220618A: BOOTES-5/JGT early optical upper limit
DATE: 22/06/18 17:16:46 GMT
FROM: Youdong HU at IAA-CSIC
Y.-D. Hu, E. Fernandez-Garcia, I. Perez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar and I. Carrasco (UMA), I. H. Park (SKKU) on behalf of a larger collaboration, report:
Following the detection of GRB 220618A by Swift (Troja et al. GCNC 32214), the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) observed the GRB location starting on Jun 18, 09:10:39 UT (~10 s after trigger). In the early co-added image (20 x 10 s exposures in the clear filter), no optical afterglow is detected within the Swift/XRT error region (Osborne et al. GCNC 32216) down to 19.5 mag. This non-detection is consistent with the UVOT results (Kuin et al. GCNC 32218) and MASTER results (Lipunov et al. GCNC 32213).
We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.
|
| GCN 32221 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32221 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32221
SUBJECT: GRB 220618A: Swift-XRT refined Analysis
DATE: 22/06/18 18:35:19 GMT
FROM: Phil Evans at U of Leicester
M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. D'Ai
(INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N.
Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester) and E. Troja report on behalf
of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 220618A (Troja et al. GCN
Circ. 32214), from 131 s to 28.0 ks after the BAT trigger. The data
comprise 235 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 32216).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.1 (+/-0.4). At T+399 s the decay
steepens to an alpha of 4.6 (+3.4, -0.7) before breaking again at
T+1148 s to a final decay with index alpha=0.26 (+0.52, -0.26).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.62 (+/-0.11). The
best-fitting absorption column is 5.9 (+0.6, -0.5) x 10^21 cm^-2, in
excess of the Galactic value of 4.7 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.0 x 10^-11 (8.4 x 10^-11) erg
cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
Total column: 5.9 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 4.7 x 10^21 cm^-2
Excess significance: 3.7 sigma
Photon index: 2.62 (+/-0.11)
If the light curve continues to decay with a power-law decay index of
0.26, the count rate at T+24 hours will be 6.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.1 x
10^-13 (5.8 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/01110821.
This circular is an official product of the Swift-XRT team.
|
| GCN 32238 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32238 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32238
SUBJECT: GRB 220618A: iTelescope T-19 upper limit
DATE: 22/06/21 00:48:42 GMT
FROM: Takanori Sakamoto at AGU
Y. Koyanagi, K. Hasuda, E. Kiuchi, N. Shimizu, T. Sakamoto (AGU)
We observed the field of GRB 220618A detected by Swift
(Troja et al., GCN Circ. 32214) with the iTelescope.Net
(http://www.itelescope.net) T19 (Planewave 17" CDK) telescope
located at the New Mexico Skies Observatory (NM, USA).
We took 10 images of 120 sec exposures in the Red filter
starting from June 18 at 09:46:36 (UT), about 0.6 hours after
the trigger and stopped at 10:09:40 (UT).
We do not detect the optical afterglow in the individual
images and the stacked image at the XRT position
(Osborne et al., GCN Circ. 32216). The estimated five sigma
upper limits of the combined image (total exposure of 1200 sec)
is 17.8 using the USNO-B1 catalog.
|
| GCN 32239 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32239 |
| Detection_method |
Swift-BAT Det |
| ra |
38.9860° |
| decl |
55.2180° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32239
SUBJECT: GRB 220618A: Swift-BAT refined analysis
DATE: 22/06/21 12:26:59 GMT
FROM: Tyler Parsotan at UMBC/GSFC/CRESST II
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 220618A (trigger #1110821)
(Troja, et al., GCN Circ. 1110821). The BAT ground-calculated position is
RA, Dec = 38.986, 55.218 deg which is
RA(J2000) = 02h 35m 56.6s
Dec(J2000) = +55d 13' 05.0"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 21%.
The BAT light curve showed a single peak structure with a duration of about 40 sec.
T90 (15-350 keV) is 96.00 +- 65.97 sec (estimated error including systematics).
The time-averaged spectrum from -15.264 to 128.736 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.26 +- 0.85,
and Epeak of 65.0 +- 16.9 keV (chi squared 53.40 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 2.2 +- 0.3 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+8.24 sec in the 15-150 keV band is
0.8 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.61 +- 0.16 (chi squared 63.41 for 57 d.o.f.). 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/1110821/BA/
|
| GCN 32241 table |
|---|
| GRB_name |
GRB220618A |
| GCN_number |
32241 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
9:10:19.590 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32241
SUBJECT: GRB 220618A: Fermi GBM detection
DATE: 22/06/21 16:48:36 GMT
FROM: Suraj Poolakkil at UAH
S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 09:10:19.59 UT on 18 June 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220618A (trigger 677236224 / 220618382)
which was also detected by the Swift/BAT (Troja et al. 2022, GCN 32214).
The angle from the Fermi LAT boresight at the GBM trigger time is 35
degrees.
The GBM light curve consists of a single peak followed
by some extended emission with a duration (T90) of about 44 s (50-300 keV).
The time-averaged spectrum from T0-4.096 s to T0+24.576 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.30 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 126 +/- 8 keV.
The event fluence (10-1000 keV) in this time interval is
(3.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+10.05 s in the 10-1000 keV band
is 2.3 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support
Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
|