GRB 220408A
GCN Circular 31847
Subject
GRB 220408A: Fermi GBM Final Real-time Localization
Date
2022-04-08T05:56:20Z (3 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 05:46:04 UT on 8 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220408A (trigger 671089569.40531 / 220408240).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 192.9, Dec = 49.7 (J2000 degrees, equivalent to J2000 12h 51m, 49d 42'), with a statistical uncertainty of 6.5 degrees.
The angle from the Fermi LAT boresight is 52.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408240/quicklook/glg_skymap_all_bn220408240.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408240/quicklook/glg_healpix_all_bn220408240.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408240/quicklook/glg_lc_medres34_bn220408240.gif
GCN Circular 31848
Subject
GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
Date
2022-04-08T06:04:40Z (3 years ago)
From
Kim Page at U.of Leicester <kimlpage1978@gmail.com>
R. Caputo (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (PSU) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 05:46:04 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220408A (trigger=1101675). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 202.402, +47.061 which is
RA(J2000) = 13h 29m 36s
Dec(J2000) = +47d 03' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a double-peaked
structure with a duration of about 5 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 05:47:53.1 UT, 109.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 202.41670, 47.06870 which is equivalent
to:
RA(J2000) = 13h 29m 40.01s
Dec(J2000) = +47d 04' 07.3"
with an uncertainty of 3.7 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 (1.98 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.6
(+4.76/-3.79) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 112 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 13:29:39.72 = 202.41548
DEC(J2000) = +47:04:09.5 = 47.06931
with a 90%-confidence error radius of about 0.91 arc sec. This position is 5.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
20.76 with a 1-sigma error of about 0.22. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.042.
We note that this GRB is in a direction near to that of M51, the
Whirlpool Galaxy, although well outside of its optical disk.
Determining whether this is a coincidence will require further study.
Burst Advocate for this burst is R. Caputo (regina.caputo AT nasa.gov).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 31849
Subject
Fermi GRB 220408A: Global MASTER-Net observations report
Date
2022-04-08T07:15:22Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-OAGH robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220408A ( Fermi GBM team, GCN 31847) errorbox 3978 sec after notice time and 4007 sec after trigger time at 2022-04-08 06:52:52 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 18 deg. The sun altitude is -51.3 deg.
The galactic latitude b = 68 deg., longitude l = 122 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1936539
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
4098 | 2022-04-08 06:52:52 | MASTER-OAGH | (13h 25m 40.01s , +47d 07m 29.9s) | C | 180 | 16.5 |
4098 | 2022-04-08 06:52:52 | MASTER-OAGH | (13h 26m 12.76s , +46d 40m 00.5s) | C | 180 | 17.7 |
4299 | 2022-04-08 06:56:13 | MASTER-OAGH | (13h 25m 46.29s , +47d 06m 27.0s) | C | 180 | 15.9 |
4299 | 2022-04-08 06:56:13 | MASTER-OAGH | (13h 26m 19.51s , +46d 38m 57.5s) | C | 180 | 17.4 |
4501 | 2022-04-08 06:59:35 | MASTER-OAGH | (13h 25m 41.42s , +47d 05m 24.8s) | C | 180 | 16.2 |
4501 | 2022-04-08 06:59:35 | MASTER-OAGH | (13h 26m 14.91s , +46d 37m 55.1s) | C | 180 | 17.7 |
4702 | 2022-04-08 07:02:56 | MASTER-OAGH | (13h 25m 46.46s , +47d 05m 45.0s) | C | 180 | 16.6 |
4702 | 2022-04-08 07:02:56 | MASTER-OAGH | (13h 26m 19.98s , +46d 38m 15.0s) | C | 180 | 17.7 |
4904 | 2022-04-08 07:06:18 | MASTER-OAGH | (13h 25m 43.83s , +47d 06m 57.3s) | C | 180 | 16.7 |
4904 | 2022-04-08 07:06:18 | MASTER-OAGH | (13h 26m 17.35s , +46d 39m 27.8s) | C | 180 | 17.7 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 31850
Subject
GRB 220408A: KAIT Optical Observations
Date
2022-04-08T09:02:14Z (3 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to the Swift GRB 220408A (Caputo et al.,
GCN 31848; see also Fermi/GBM detection, GCN 31847) starting at
06:30:47 UT, ~44 min after the burst. Observations were performed
with a sequence in the clear (roughly R), V, and I filters, and the
exposure time was 20s per image. We did not detect the optical afterglow
reported by UVOT (Caputo et al., GCN 31848) in any of our single images.
We marginally detected the afterglow in the coadd image in clear band,
which we measured its brightness of 21.4 +/- 0.3 mag at ~53 min after the
burst, calibrated to the Pan-STARRS1 catalog.
GCN Circular 31851
Subject
Chandra upper limit at the location of GRB 220408A
Date
2022-04-08T10:23:23Z (3 years ago)
From
Sergio Campana at INAF-OAB <sergio.campana@brera.inaf.it>
S. Campana (INAF - Osservatorio astronomico di Brera) reports
that Chandra serendipitously observed the location of GRB 220408A
(Caputo et al. 2022, GCN 31848; Fermi team 2022, GCN 31847).
The UVOT position (Caputo et al. 2022) falls at the edge of the S4 chip
of ACIS-S. The obsid 23474 observation lasted 36.6 ks and was taken on
Dec 21, 2020.
No source is visible at this position.
We run srcflux (under CIAO 4.13 and CALDB 4.9.7) and derive a 3-sigma
upper limit of 0.000206 c/s (2.38E-05,0.000432) on the 0.5-7 keV count
rate. Assuming a power law photon index of 2 and a column density of
2x10^20 cm^-2, we derive an upper limit on the 0.5-7 keV unabsorbed flux
of 2.1e-14 erg/cm2/s.
If the GRB were at the M51 distance (8.58 Mpc), this translates into an
upper limit on the 0.5-7 keV luminosity of 1.8e38 erg/s.
GCN Circular 31852
Subject
GRB 220408A: Enhanced Swift-XRT position
Date
2022-04-08T11:09:55Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1138 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 220408A, 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 = 202.41658, +47.06912 which is equivalent
to:
RA (J2000): 13h 29m 39.98s
Dec (J2000): +47d 04' 08.8"
with an uncertainty of 2.0 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 Circular 31853
Subject
GRB 220408A: Xinglong-2.16m optical upper limit
Date
2022-04-08T13:30:31Z (3 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Q. Jiang, S.Y. Fu, X. Liu, D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), L.P.
Xin, J.Y. Wei, G.W. Li (NAOC) report on behalf of a larger collaboration:
We observed the field of GRB 220408A detected by Swift (Caputo et al.,
GCN 31848) and Fermi (Fermi GBM team, GCN 31847) using the
Xinglong-2.16m telescope equipped with the BFOSC camera. Observations
were carried out starting at 12:02:32 UT on 2022-04-08 (i.e., 6.27 hr
since the BAT trigger), and 9x400 s frames in the R-band were obtained.
The previously reported optical counterpart (e.g., Caputo et al., GCN
31848; Zheng & Filippenko, GCN 31850) is not detected in our stacked
image, down to a limiting magnitude of R ~ 20.7 (Vega) at 6.79 hr
post-burst, calibrated with the nearby SDSS field.
GCN Circular 31855
Subject
GRB 220408A: Swift/UVOT Detection
Date
2022-04-08T15:34:23Z (3 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U.Birmingham) and R. Caputo (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220408A
112 s after the BAT trigger (Caputo et al., GCN Circ. 31848).
A source consistent with the XRT position (Beardmore et al., GCN Circ. 31852)
is detected in the initial white UVOT exposure only.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (FC) 112 262 147 20.30 +/- 0.22
white 605 799 40 >21.4
v 655 675 19 >19.3
b 581 774 39 >20.7
u 325 575 246 >20.2
w1 704 724 19 >17.9
m2 679 699 19 >17.4
w2 631 650 19 >17.7
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.042 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 31856
Subject
GRB 220408A: Fermi GBM observation
Date
2022-04-08T17:49:46Z (3 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
E. Bissaldi (Politecnico and INFN Bari) reports on behalf of the Fermi GBM
Team:
"At 05:46:04.41 UT on 8 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 220408A (trigger 671089569/ 220408240), which was also detected by the Swift/BAT (Caputo et al. 2022, GCN 31848).
The Fermi GBM Final Real-time Localization (GCN 31847) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 57 degrees.
The GBM light curve consists of a multipeaked emission episode with a duration (T90) of about 20 s (50-300 keV).
The time-averaged spectrum from T0-0.8 s to T0+6.7 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.72 +/- 0.14 and the cutoff energy, parameterized as Epeak, is 48.8 +/- 2.3 keV.
The event fluence (10-1000 keV) in this time interval is (1.33 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.4 s in the 10-1000 keV band is 7.7 +/-0.3 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/"
GCN Circular 31857
Subject
GRB 220408A: GIT optical upper limit
Date
2022-04-08T19:05:42Z (3 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), V. Bhalerao (IITB), G. C.
Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 220408A detected by Fermi-GBM (GCN #31847) and Swift-BAT
(R. Caputo et al., GCN #31848) with 0.7m GROWTH-India Telescope (GIT). We
obtained multiple 300-sec exposures in the r' filter and did not detect the
afterglow in our stacked images. The obtained upper limits follow as:
---------------------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |
---------------------------------------------------------------------------------
2459678.21683 | 11.43 | 3000(stacked) | r' | > 21.94
---------------------------------------------------------------------------------
The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016)
and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics (IIA) and the
Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and
IUSSTF. It is located at the Indian Astronomical Observatory (Hanle),
operated by IIA. We acknowledge funding by the IITB alumni batch of 1994,
which partially supports operations of the telescope. Telescope technical
details are available at https://sites.google.com/view/growthindia/.
GCN Circular 31859
Subject
GRB 220408A: BOOTES-5/JGT optical afterglow detection
Date
2022-04-08T23:17:25Z (3 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, R. Sanchez-Ramirez and M.D. Caballero-Garcia (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 220408A by both Swift (Caputo et al. GCNC 31848) and Fermi (Fermi GBM team, GCNC 31847), the 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically responded to the burst on Apr 8 at 06:14 UT (i.e. ~ 28 min after trigger). In the co-added image (5 frames x 60 s exposure, clear filter), the optical afterglow is weakly detected with R = 21.1 +/- 0.3 mag at the position reported by UVOT (Caputo et al. GCNC 31848) and within the XRT error box (Beardmore et al. GCNC 31852). This is consistent with other optical detections previously reported by UVOT (Caputo et al. GCNC 31848, Oates et al. GCNC 31855) and KAIT (Zheng et al. GCNC 31850) and the upper limits provided by MASTER (Lipunov et al. GCNC 31849), Xinglong-2.16m (Jiang et al. GCNC 21853) and GIT (Kumar et al. GCNC 31857). Further observations are ongoing.
We thank the staff at San Pedro Martir Observatory for their excellent support.
GCN Circular 31861
Subject
GRB 220408A: Swift-XRT refined Analysis
Date
2022-04-09T08:44:36Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC &
INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (PSU), D.N.
Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester) and R. Caputo report on behalf of the Swift-XRT
team:
We have analysed 7.5 ks of XRT data for GRB 220408A (Caputo et al. GCN
Circ. 31848), from 93 s to 63.6 ks after the BAT trigger. The data
comprise 10 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Beardmore et al. (GCN Circ.
31852).
The light curve can be modelled with an initial power-law decay with an
index of alpha=0.46 (+0.16, -0.17), followed by a break at T+2306 s to
an alpha of 1.37 (+0.16, -0.15).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+0.23, -0.22). The
best-fitting absorption column is 1.8 (+0.8, -0.7) x 10^21 cm^-2, in
excess of the Galactic value of 2.0 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.6 x 10^-11 (4.8 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.8 (+0.8, -0.7) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: 3.8 sigma
Photon index: 1.94 (+0.23, -0.22)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01101675.
This circular is an official product of the Swift-XRT team.
GCN Circular 31862
Subject
GRB 220408A: LCO Optical Afterglow Detection
Date
2022-04-09T10:15:46Z (3 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@uvi.edu>
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:
We observed Swift (Caputo et al. GCN 31848) and Fermi (Fermi GBM team, GCN 31847) GRB220408A with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site, on April 9, from 06:30 to 06:57 UT (corresponding to 0.63 to 1.18 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 3x300s exposures in I and R bands. We detect an optical counterpart within the XRT enhanced error region (Beardmore et al., GCN 31852) in both bands, consistent with other optical detections (Caputo et al. GCNC 31848, Zheng et al. GCNC 31850, Oates et al. GCNC 31855). The following magnitudes are calculated using the USNO-B.1 catalog as reference:
R=21.66+/-0.17
I=19.63+/-0.11
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682
GCN Circular 31864
Subject
GRB 220408A: NOT optical observations and archival detection
Date
2022-04-09T14:01:01Z (3 years ago)
From
Zipei Zhu at NAOC <zpzhu@nao.cas.cn>
Z. Zhu (NAO/CAS, HUST), D. Xu, S.Y. Fu (NAOC/CAS), D. B. Malesani (Radboud Univ and DAWN/NBI), A. de Ugarte Postigo (Obs. Cote d'Azur), A. J. Levan (Radboud univ.), M. Aron (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 220408A detected by Swift (Caputo et al., GCN 31848) and Fermi (Fermi GBM team, GCN 31847) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were carried out starting at 03:53:08 UT on 2022-04-09 (i.e., 0.92 day since the BAT trigger), and 6x300 s frames in the SDSS r-band were obtained.
The previously reported optical counterpart (e.g., Caputo et al., GCN 31848; Zheng & Filippenko, GCN 31850; Oates et al., GCN 31855; Hu et al., GCN 31859; Strausbaugh & Cucchiara, GCN 31862) is detected in our stacked image with r = 24.1 +/- 0.1 AB, calibrated against nearby stars from the Pan-STARRS catalog.
We note that this field was covered by an image taken in 2007 with CFHT. Consistent with the UVOT coordinates, a faint source is visible with r = 24.5 +/- 0.2 (AB). While the S/N is not large, and we cannot conclusively determine whether this object is extended, it is a viable host galaxy candidate, suggesting a distance to the GRB much larger than M51.
We encourage spectroscopic observations of this Northern target to conclusively measure.
GCN Circular 31865
Subject
GRB 220408A: redshift lower limit estimating
Date
2022-04-09T15:51:10Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
P. Minaev (IKI), A. Pozanenko (IKI) report on behalf of GRB IKI FuN:
We analysed GRB 220408A detected by Fermi (Fermi GBM team, GCN 31847;
Bissaldi et al., GCN 31856), by Swift (GCN Caputo et al., GCN 31848).
Using publicly available data of GBM/Fermi we estimate the duration
T_90 = 32.3 +/- 2.5 s in (7 - 150) keV energy band. We performed
spectral analysis in a time interval of (-1, 22) s since GBM trigger,
the best fit is obtained for Band model with following parameters: E_p =
36.5 +/- 5.0 keV, alpha = -0.50 +/- 0.35, beta = -2.5 +/- 0.2. The
fluence of F = (2.0 +/- 0.2)E-6 erg/cm**2 is obtained in 10 - 1000 keV
energy band. Using T_90,i - EH diagram [1,2] we can classify the burst
as type II (long) and find the minimal possible redshift value of z =
0.03, which is excluding possible association with M51 galaxy and
confirming larger distance of GRB 220408A (Zhu et., GCN 31864).
The T_90,i - EH diagram can be found in
http://grb.rssi.ru/GRB220408A/GRB220408A_EHD.png
[1] - Minaev et al., MNRAS, 492, 1919, 2020
[2] - Minaev et al., Astronomy Letters, 46, 9, 573, 2020
GCN Circular 31867
Subject
GRB 220408A: LOAO, DOAO, and, SAO optical upper limit
Date
2022-04-10T03:03:22Z (3 years ago)
From
Gregory SungHak Paek at SNU <shpaek@astro.snu.ac.kr>
Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Taewoo Kim
(DOAO), Jinguk Seo (SAO), Yuji Urata (NCU), Hyun-Il Sung (KASI) on behalf
of a larger collaboration
We searched for the optical counterpart of GRB 220408A possibly associated
with M51 (Caputo et al., and GCN #31848; Fermi/GBM detection, GCN #31847)
with the 1-m class telescopes in Lemonsan Optical Astronomy Observatory
(LOAO), Deokheung Optical Astronomy Observatory (DOAO), and Seoul National
University Astronomy Observatory (SAO), facilities of the GW EM-Counterpart
Korean Observatory (GECKO).
We observed the center of UVOT localization (RA, Dec = 202.41548,
+47.06931) +2.94 hours after the report, but could not find any detection.
We calibrated flux with the PANSTARRS catalog and used an AB magnitude
system. Depth means 5 sigma upper limit for a point source detection. The
magnitudes are not corrected for galactic extinction.
------------------- ----------- ---------- ----=------ ------ -----------
---------- -----
DATE-OBS[UTC] JD t-t0[days] t-t0[hours] FILTER Observatory
EXPTIME[s] DEPTH
------------------- ----------- ---------- ----=------ ------ -----------
---------- -----
2022-04-08T11:29:38 2459677.979 0.239 5.7 R LOAO
180s*12 21.42
2022-04-08T15:44:59 2459678.156 0.416 10.0 V SAO
180s*21 19.75
2022-04-08T15:57:20 2459678.165 0.424 10.2 R DOAO
300s*37 21.90
2022-04-08T16:58:50 2459678.208 0.467 11.2 R SAO
180s*21 19.77
Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network
of 10+ 0.5m to 1m class telescopes over the world.
GCN Circular 31868
Subject
GRB 220408A: 1.3m DFOT Optical upper limit
Date
2022-04-10T12:07:00Z (3 years ago)
From
Amit Kumar at ARIES, India <amitkundu515@gmail.com>
Amit Kumar, Rahul Gupta, Amit K. Ror, Nikita Rawat, Dimple, Ankur Ghosh,
Amar Aryan, Brajesh Kumar, Shashi B. Pandey and Kuntal Misra (ARIES)
report:
We observed the field of the Swift-BAT (Caputo et al., GCN 31848) and
Fermi-GBM (GBM Team, GCN 31847) detected GRB 220408A with the 1.3m
Devasthal Fast Optical Telescope (DFOT) located at Devasthal observatory of
Aryabhatta Research Institute of Observational Sciences (ARIES), India. We
started the observations on 2022-04-08 at 16:27:57 UT, i.e., ~10.698 hours
after the GBM trigger. We have observed 300s*23 frames in each Bessel R and
I filters. We stacked the images after the pre-processing and alignment. We
did not detect the optical afterglow at the Swift-XRT position (Beardmore
et al., GCN 31852) in our stacked images; see also Caputo et al., GCN
31848; Zheng & Filippenko, GCN 31850; Jiang et al., GCN 31853; Oates &
Caputo, GCN 31855; Kumar et al., GCN 31857; Hu et al., GCN 31859;
Strausbaugh et al., GCN 31862; Zhu et al., GCN 31864; and Gregory et al.,
GCN 31867.
We obtain the following 3-sigma upper limits in the stacked images.
Date Start_UT T_start-T0 (hour) Filter Exp time(s) Limiting magnitude
====================================================
2022-04-08 16:27:57 ~10.698 R 300s*23 >22.5
2022-04-08 18:29:56 ~12.731 I 300s*23 >22.1
The magnitudes are not corrected for the Galactic extinction in the burst
direction. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalogue.
During our observations, the moon phase and its distance were ~45% and
~55-66 degrees, respectively, which affected our deeper limits
significantly; see Kumar et al. 2021, JAA, arXiv:2111.13018 (
https://ui.adsabs.harvard.edu/abs/2000A%26A...363..705M/abstract) for the
sky brightness of the Devasthal site w.r.t. the moon phase and distance.
Assuming a typical temporal flux decay index of the early afterglows
(alpha~0.7), the extrapolated brightness at the epoch of our observation is
consistent with the quoted non-detection. Deeper observations using the
larger facilities will be useful to establish the fast decaying nature of
the burst and to investigate for this burst to happen in any
distant/background galaxy rather than Whirlpool Galaxy (M51a).
This message may be cited.
GCN Circular 31870
Subject
GRB 220408A: RATIR Optical and NIR Observations
Date
2022-04-10T17:38:55Z (3 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Eleonora Troja (GSFC), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (UMD), and Oc��lotl L��pez (UNAM) report:
We observed the field of GRB 220408A (Caputo et al., GCN Circ. 31848) with the Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir from 2022/04 9.13 to 2022/04 9.49 UTC (20.98 to 29.45 hours after the BAT trigger), obtaining a total of 3.27 hours exposure in the r and i bands and 2.10 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following weak detection and 3-sigma upper limits:
r > 23.76
i > 23.45
Z > 21.36
Y > 22.04
J > 21.79
H = 21.27 +/- 0.23
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We note that while we have a formal detection in H, the large errors call it into doubt.
Our limit in r is consistent with the fainter and slightly earlier detection at r = 24.1 reported by Zhu et al. (GCN Circ. 31864).
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro M��rtir.
GCN Circular 31874
Subject
GRB 220408A: Swift-BAT refined analysis
Date
2022-04-11T12:34:25Z (3 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), R. Caputo (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-119 to T+183 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 220408A (trigger #1101675)
(Caputo, et al., GCN Circ. 31848). The BAT ground-calculated position is
RA, Dec = 202.399, 47.065 deg which is
RA(J2000) = 13h 29m 35.7s
Dec(J2000) = +47d 03' 55.4"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 34%.
The mask-weighted light curve shows a multi-peaked structure that
starts at T-2 s and peaks at T+3 s. There is a weak emission which
peaks at T+17 s. T90 (15-350 keV) is 17.25 +- 1.10 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.55 to T+18.26 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.19 +- 0.57,
and Epeak of 35.3 +- 8.8 keV (chi squared 62.40 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+2.48 sec in the 15-150 keV band is
4.9 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index
of 2.14 +- 0.13 (chi squared 72.77 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/1101675/BA/
GCN Circular 31875
Subject
GRB 220408A: Lowell Discovery Telescope Optical Observations
Date
2022-04-11T13:55:36Z (3 years ago)
From
Brendan O'Connor at UMD <oconnorb@umd.edu>
B. O'Connor (UMD, GWU), S.B. Cenko (UMD,NASA-GSFC), E. Troja (UTV),
S. Dichiara (PSU), A. Kutyrev (UMD,NASA-GSFC), S. Veilleux (UMD)
We observed GRB 220408A with the Large Monolithic Imager (LMI) on the 4.3m
Lowell Discovery Telescope (LDT). Observations began on April 9, 2022
at 06:25:23 UT in r-band (~1.03 d after the GRB). At the location of the
optical counterpart (Caputo et al., GCN 31848), we marginally detect a
source with magnitude r~24.5 +/- 0.3 AB mag. This is likely dominated by
the contribution from the host galaxy (Zhu et al., GCN 31864), and is
consistent with fading of the earlier detection by Zhu et al. (GCN 31864).
Magnitudes are calibrated against the PS1 catalog and are not corrected
for Galactic extinction.
We thank the staff of the Lowell Discovery Telescope for assistance
with these observations.
GCN Circular 31884
Subject
GRB 220408A: GRANDMA observations
Date
2022-04-12T15:20:13Z (3 years ago)
From
Sarah Antier at OCA <sarah.antier@oca.eu>
S. Beradze (AbAO), U. Bhardwaj (GRAPPA), T. Culino (ESILV), P. Hello
(IJCLAB), M. Masek (FZU), G. Raaijmakers (GRAPPA), Y. Rajabov (UBAI),
T. Sadibekova (AIM/CEA-UPS), F. Z. Guo (THU), X. F. Wang (THU/BJP), Y.
Zhu (NAOC), J. Zhang (NAOC), D. A. Kann (HETH/IAA-CSIC), K. Noysena
(TRT-SRO), C. Rinner (OUCA), Z. Benkhaldoun (OUCA), J. Zhu (BJP),
X. Song (BJP), S. Antier (OCA/Artemis), P. A. Duverne (IJCLAB), A. Simon
(Kyiv Univ), A. Baransky (Kyiv Univ) and V. Godunova (IC ICAMER)
report on behalf of GRANDMA collaboration:
The GRANDMA telescope network responded to the alert of GRB 220408A
(Caputo et al. GCNC 31848). The first observations started 0.63 h after
the SWIFT BAT trigger time.
We did not detect the optical afterglow within the first 24 h.
Upper limits are given in the AB system, at 3-sigma.
T-T0(hr)| MJD������ | Observatory�� | Exposure| Filter | Upp. Lim. (AB)
___________________________________________________________________________
0.63 |59677.26659|KNC-T19������������ |9*300 s�� |�� V ������ ���� |���� 17.7
1.82 |59677.31602|SRO�������������������� |7*60 s���� |�� R ������ ���� |���� 19.8
6.27 |59677.50176|Xinglong-2.16m|9*400 s�� |�� Rc������ ���� |���� 20.3
8.45 |59677.59259|BJP/ALi-50������ |21*20 s�� |�� Clear |���� 21.4
14.89|59677.86076|MOSS������������������ |45*60 s�� |�� Clear |���� 20.3
18.76|59678.02215|KNC-HAO������������ |23*180 s |�� Lumen |���� 20.6
These upper limits are consistent with previous reports of detections by
UVOT (Caputo et al. GCNC 31848, Oates et al. GCNC 31855), KAIT (Zheng et al.
GCNC 31850), LCO (R. Strausbaugh et al. GCNC 31862), NOT (Zhu et al. GCNC
31864), RATIR (Watson et al. GCNC 31870), and LDT (B. O'Connor et al. GCNC
31875), and the upper limits provided by MASTER (Lipunov et al. GCNC 31849),
Xinglong-2.16m (Jiang et al. GCNC 31853), GIT (Kumar et al. GCNC 31857),
LOAO/SAO/DOAO (Paek et al. GCNC 31867), and 1.3m DFOT (Kumar et al. GCNC
31868).
The SRO, Xinglong-2.16m, and Ali-50 data have been calibrated with four
stars
from the Pan-STARRS catalog, using the transformations by Lupton (2005) and
using Rc values for the Clear Al-50 observation. The MOSSm KNC-T19 and
KNC-HAO images have been calibrated using field stars from the
PanSTARRS-DR1
catalog, measured with the MUPHOTEN pipeline (Duverne et al. 2021).
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr)
devoted to the observation of transients in the context of multi-messenger
astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is
the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular 31893
Subject
GRB 220408A: HCT optical upper limit
Date
2022-04-13T08:52:20Z (3 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), G. C. Anupama (IIA), S.
Barway (IIA), V. Bhalerao (IITB), A. Dutta (IIA), R. Gupta (ARIES), K.
Misra (ARIES), D. Panchal (ARIES), S.B. Pandey (ARIES), D.K. Sahu (IIA)
report on behalf of the HCT team:
We observed GRB 220408A detected by the Fermi-GBM (GCN # 31847), Swift-BAT
(R. Caputo et al., GCN #31848) and optical afterglow discovered by Swift-UVOT
(GCN #31848) with the 2.0m Himalayan Chandra Telescope (HCT) of the Indian
Astronomical Observatory (IAO). We obtained multiple exposures in the Rc
and Ic filters. We did not detect any new source in our stacked image at
the afterglow location.
The obtained upper limit follows as:
-------------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |
-------------------------------------------------------------------------
2459678.203981 | 11.13 | 300 x 3 (stacked) | Rc | > 22.51 |
2459678.225509 | 11.64 | 300 x 3 (stacked) | Ic | > 22.46 |
-------------------------------------------------------------------------
Our upper limits are consistent with results from R. Caputo et al. (GCN
#31848), W. Zheng and A.V. Filippenko (GCN #31850), S.Q. Jiang et al. (GCN
#3185), S.R. Oates & R. Caputo (GCN #31855), H. Kumar et al. (GCN #31857),
Y.-D. Hu et al. (GCN #31859), R. Strausbaugh et al. (GCN #31862), Z. Zhu et
al. (GCN #31864), G.S.H. Paek et al. (GCN #31867), A. Kumar et al. (GCN
#31868), A.M. Watson et al. (GCN #31870), B. O'Connor et al. (GCN #31875),
S. Beradze et al. (GCN #31884).
The magnitudes are in the AB system of magnitude, calibrated against
PanSTARRS (Flewelling et al., 2018) using Lupton's transformation equations
available at
http://classic.sdss.org/dr4/algorithms/sdssUBVRITransform.html#Lupton2005.
The magnitudes are not corrected for galactic extinction.
These observations were carried out under the ToO program HCT-2022-C1-P14
(PI: Harsh Kumar). We thank the HCT staff for their support during the
observations. The Indian Astronomical Observatory is operated by the Indian
Institute of Astrophysics, Bengaluru, India.
GCN Circular 32327
Subject
GRB220408A: VIRT Optical Upper Limit
Date
2022-07-05T17:55:28Z (3 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
K. Noonan (UVI), P. Gokuldass (Florida Institute of Technology), N. Orange
(OrangeWave Innovative Science, LLC), K. Smith (UVI), D. Morris (UVI)
report:
We observed the field of GRB220408A (Caputo et al., GCN 31848) with the
0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 04-08-2022 starting at 23:53:07.963 UT
(T+18.7 hrs). We performed a series of exposures in the R filter with a
total exposure of 6180 s. The weather conditions were partly cloudy during
the hours of observation with an average airmass of 1.5.
We detect no new source within the enhanced XRT position error circle (A.P.
Beardmore et al., 31852), consistent with other non-detections ( Zheng &
Filippenko, GCN 31850; Jiang et al., GCN 31853; Kumar et al., GCN 31857;
and Gregory et al., GCN 31867) and report the following 5-sigma upper
limit:
T_mid ||Exposure ||Filter ||Limit
T+ 19.5 hrs ||6180s ||R ||>20.8
The limit is estimated from comparison to nearby USNO B1 stars and is not
corrected for Galactic extinction. The VIRT is still in the commissioning
phase.
We acknowledge financial support from NASA MUREP MIRO award 80NSSC21M0001, NASA
EPSCoR award 80NSSC19M0060, and NSF EiR award 1901296.This message can be
cited.