GRB 230414B
GCN Circular 33636
Subject
GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
Date
2023-04-16T19:21:38Z (4 years ago)
From
Rahul Gupta at ARIES, India <rahulbhu.c157@gmail.com>
Amit K. Ror, Rahul Gupta, S. B. Pandey, A. Aryan, K. Misra (ARIES), A. J.
Castro-Tirado (IAA-CSIC), D. Bhattacharya (Ashoka University/IUCAA), and V.
Bhalerao (IITB) report on behalf of a larger collaboration:
We observed the field of GRB 230414B (D'Ai et al. GCN 33612; and Evans et
al. GCN 33613) using the TANSPEC mounted at the axial port of the 3.6m
Devasthal Optical Telescope (DOT) of ARIES Nainital. We have taken multiple
frames with an exposure time of 300 sec each in r, and i filters on
2023-04-14 and successive nights. We clearly detect the optical afterglow
(Pankov et al. GCN 33615; Lu et al. GCN 33616; Raman et al. GCN 33618;
Ghosh et al. GCN 33620; Moskvitin et al. GCN 33622; Malesani et al. GCN
33623; Zhu et al. GCN 33625; Belkin et al. GCN 33628; Fernandez et al. GCN
33629; Quadri et al. GCN 33630; and Leonini et al. GCN 33634) in each
individual image taken on 2023-04-14. We report the preliminary brightness
of the afterglow to be i = 19.95 +/- 0.16 mag ~ 43 minutes after the BAT
trigger. By combining our i-band magnitude with the observations of Raman
et al. GCN 33618, we determine the preliminary flux decay index of 0.60
+/-0.08. Our observations indicate the slow flux decay behavior of the
afterglow at the early epoch, as also noted by Malesani et al. GCN
33623. Late-time
observations will further provide insight into jet geometry, circumburst
medium, and the total energy of the burst.
The magnitude quoted is not corrected for the Galactic and host extinctions
in the direction of the burst. Photometric calibration is performed using
the standard stars from the PanSTARRS catalog.
This circular may be cited. 3.6m Devasthal Optical Telescope (DOT) is the
recently commissioned facility in the Northern Himalayan region of India
(long:79 41 04E, lat:29 21 40N, alt:2540m) owned and operated by the
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (
https://www.aries.res.in). Authors of this GCN circular thankfully
acknowledge consistent support from the staff members to run and maintain
the 3.6m DOT.
GCN Circular 33634
Subject
GRB 230414B: Montarrenti Observatory late time optical afterglow detection
Date
2023-04-16T13:28:28Z (4 years ago)
From
Simone Leonini at Monarrenti Obs <s.leonini@iol.it>
Simone Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy) and B. De Simone (Universita' degli Studi Di Salerno) report:
We observed the field of GRB 230414B (Swift trigger 1164180, A. D'Ai et al. GCN 33612; Lipunov GCN 33614; Pankov et al. GCN 33615; Lu et al. GCN 33616; Raman et al. GCN 33618; Ghosh et al. GCN 33620; Moskvitin et al. GCN 33622; Malesani et al. GCN 33623; Zhu et al. GCN 33625; Gupta et al. GCN 33627; Belkin et al. GCN 33628; Agui Fernandez et al. GCN 33629; Quadri & Strabla GCN 33630; Chen et al. GCN 33631) with the automatic 0.53m RC telescope + U47 detector at Montarrenti Observatory (Siena, Italy, IAU code C88).
The observations were started in a windy night under mediocre seeing conditions at 2023-04-15 21:18:31 UT (approximately 29 hours after burst) stacking 20x30s unfiltered CCD exposures.
The optical afterglow was detected at the following position:
RA (J2000.0) 12h 04m 22.68s +/-0.22
Decl. (J2000.0) +53�� 09' 17.2" +/-0.28
Preliminary photometry is obtained using nearby USNO-B1 stars as follows:
2023 Apr 15.89133 UT (21:23:31 mid-time) CR=21.53 +/-0.18
Measures are not corrected for galactic dust extinction
GCN Circular 33631
Subject
GRB 230414B: Lulin 40cm-SLT optical limit
Date
2023-04-15T15:36:17Z (4 years ago)
From
Ting-Wan Chen at MPE <janet.chen@astro.su.se>
T.-W. Chen (TUM/MPA), S. Yang (HNAS), C.-S. Lin, C.-C. Ngeow, H.-Y. Hsiao, W.-J. Hou, Y.-C. Pan, H.-C. Lin, and J.-K. Guo (IANCU) report:
We observed the field of GRB 230414B (D'Ai et al. GCN 33612; Evans et al. GCN 33613; Lipunov GCN 33614; Pankov et al. GCN 33615; Lu et al. GCN 33616; Raman et al. GCN 33618; Ghosh et al. GCN 33620; Goad GCN 33621; Moskvitin et al. GCN 33622; Malesani et al. GCN 33623; Zhu et al. GCN 33625; Gupta et al. GCN 33627; Belkin et al. GCN 33628; Agui Fernandez et al. GCN 33629; Quadri & Strabla GCN 33630), using the 40cm-SLT at Lulin Observatory, Taiwan to obtain r-band images as part of the Kinder collaboration (Chen et al., AstroNote 2021-92).
The first epoch of observations started at 17:01 UT on 14 of April 2023 (MJD = 60048.709), 46 minutes (0.032 days) after the Swift/BAT trigger. The images were combined from 6 frames with a 300-second exposure time for the r band, taken under seeing conditions of an average of 1.85" and at a median airmass of 1.37. We note that the QE of the current testing camera mounted on the SLT is much shallower than the previous one. After template subtraction using the SDSS image, we do not detect a source at the position of the afterglow down to the following preliminary 2.5-sigma limit (in the AB system):
r > 19.18 mag.
The given limit is derived based on calibrating against SDSS field stars and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.01 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular 33630
Subject
GRB 230414B: Bassano Bresciano Observatory optical observations
Date
2023-04-15T14:51:21Z (4 years ago)
From
Ulisse Quadri at Bassano Bresciano Obs <oabb@ulisse.bs.it>
U.Quadri, L.Strabla report:
We imaged the field of GRB 230414B detected by SWIFT(trigger 1164180)
with the robotic telescope of (IAU station 565) Bassano Bresciano
Observatory, Italy. Member of:
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
The observations started 236.82 min min after the GRB trigger, at the end of twilight,
with our Newton telescope D=250 mm F/D=4.8.
We co-added 6 series of 30 exposures of 60 sec each.
Start T0+ End T0+ Vlim
236.82 min 323.07 min 20.5
We detected a (fading) afterglow in the error box of the XRTcandidate.
A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA), et al.
at the following position (+/- 2 arcsec):
RA (J2000.0) = 12h 04m 22.64s
DEC(J2000.0) = +53�� 09' 16.4"
The results of our photometry are:
-----------------------------------------
Date UT CR-mag
Middle +/- 0.05
-----------------------------------------
2023 04 14.85273 19.76
2023 04 14.86022 19.74
2023 04 14.86771 19.76
2023 04 14.87519 20.02
2023 04 14.88268 19.96
2023 04 14.89017 20.01
-----------------------------------------
Magnitudes were estimated with the UCAC4 cat. and
are not corrected for galactic dust extinction.
The images are available at:
http://www.osservatoriobassano.org/GRB.asp
The message may be cited.
GCN Circular 33629
Subject
GRB 230414B: Redshift from OSIRIS/GTC
Date
2023-04-15T12:00:39Z (4 years ago)
From
J. F. Agui Fernandez at IAA-CSIC <feli@iaa.es>
J. F. Agui Fernandez (IAA-CSIC), C. C. Thoene (ASU-CAS),
A. de Ugarte Postigo (OCA), R. Scarpa, A. Marante and
A. L. Cabrera Lavers (GTC, IAC) report:
We observed the afterglow of GRB 230414B (D'Ai et al. GCN
33612; Evans et al. GCN 33613; Lipunov GCN 33614; Pankov et al.
GCN 33615; Lu et al. GCN 33616; Raman et al. GCN 33618;
Ghosh et al. GCN 33620; Goad GCN 33621; Moskvitin et al.
GCN 33622; Malesani et al. GCN 33623; Zhu et al. GCN 33625)
with OSIRIS at the 10.4m GTC telescope, at the Roque de los
Muchachos Observatory (La Palma, Spain). Observations consisted
of 4x1200 s spectroscopy with grism R1000B, covering the
spectral range between 3700 and 7800 AA.
In a preliminary analysis we identify a broad absorption that we
interpret as due to Ly-alpha. We also see several transitions
coincident with SI, SiII, SiII*, OI, CII, NiII, SiIV, CIV and FeII, all of
them at a common redshift of z = 3.568, which we interpret as
the redshift of the GRB.
This GCN is in honor of the great Alex Kann, the WiseGRBguy.
It happened on the day he was buried while some of
his colleagues were standing at the grave saying farewell.
Even the Universe paid its tribute to him.
GCN Circular 33628
Subject
GRB 230414B: AbAO optical observations
Date
2023-04-15T11:15:00Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), R. Ya. Inasaridze (AbAO), A. Pozanenko (IKI), N.
Pankov (HSE, IKI), D. Datashvili (AbAO), V. R. Ayvazian (AbAO), report
on behalf of GRB IKI FuN:
We observed the field of Swift GRB 230414B (D'Ai et al., GCN 33612)
with AS-32 telescope of Abastumani observatory (AbAO) in R-filter
starting on Apr. 14 (UT) 16:46:07. We detected the afterglow (Pankov
et al., GCN 33615; Lu et al., GCN 33616; Raman et al., GCN 33618; Ghosh
et al., GCN 33620; Moskvitin et al., GCN 33622; Malesani et al., GCN
33623; Zhu et al., GCN 33625). Preliminary photometry of the object is
following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2023-04-14 16:46:07 0.06094 R 112*60 19.73 0.05 22.3
The photometry is based on nearby USNO-B1.0 stars.
GCN Circular 33626
Subject
GRB 230414B: Swift-XRT refined Analysis
Date
2023-04-15T05:39:47Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , J. D. Gropp
(PSU), S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), M. Capalbi
(INAF-IASFPA) and A. D'Ai report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 230414B (D'Ai et al. GCN
Circ. 33612), from 112 s to 34.3 ks after the BAT trigger. The data
comprise 17 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 Goad et al.
(GCN Circ. 33613). The late-time light curve (from T0+4.4 ks) is
consistent with a constant source of mean count rate 2.2e-01 ct/sec. A
power-law fit gives an index of -0.07 (+/-0.15).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.97 (+0.16, -0.10). The
best-fitting absorption column is 1.74 (+3.05, -0.07) x 10^20 cm^-2,
consistent with the Galactic value of 1.7 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 3.2 x 10^-11 (3.4 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.74 (+3.05, -0.07) x 10^20 cm^-2
Galactic foreground: 1.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.97 (+0.16, -0.10)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01164180.
This circular is an official product of the Swift-XRT team.
GCN Circular 33625
Subject
GRB 230414B: Dabancheng/GHOST optical observations
Date
2023-04-15T05:39:21Z (4 years ago)
From
Zipei Zhu at NAOC <zpzhu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, S.Q. Jiang, X. Liu, T.H. Lu, D Xu (NAOC), S.W. Luo, M.M. Yang, Z. K. Feng (Gaoyazi Obs.) reoport:
We observed the field of GRB 230414B detected by Swift (A. D'Ai et al., GCN 33612) with the GHOST-0.5m telescope located at Dabancheng, Xinjiang,
China. Observations started at 18:27:56 UT on 2023-04-14, i.e., 2.23 hr after the Swift/BAT trigger, and 20x120 s images were obtained all in the Sloan r filter.
The afterglow reported before (Pankov et al., GCN 33615; Lu et al., GCN 33616; Raman et al., GCN 33618; Ghosh et al., GCN 33620; Moskvitin et al., GCN 33622; Malesani et al., GCN 33623) is clearly detected in the stacked image with a brightness of r = 20.1 +/- 0.1 mag, calibrated with nearby stars from the Pan-STARRS catalog.
GCN Circular 33623
Subject
GRB 230414B: slow optical light curve decay
Date
2023-04-14T23:47:27Z (4 years ago)
From
Daniele B Malesani at Radboud U <d.malesani@astro.ru.nl>
D. B. Malesani (Radboud Univ. and DAWN/NBI), A. de Ugarte Postigo (OCA),
L. Izzo (DARK/NBI), D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), J. Acevedo
Barroso (EPFL), C. Lemon (EPFL), Z. Gray (AOP), F. Neira (EPFL), report
on behalf of a larger collaboration:
We observed the optical afterglow (Pankov et al., GCN 33615; Lu et al.,
GCN 33616; Raman et al., GCN 33618; Ghosh et al., GCN 33620; Moskvitin
et al., GCN 33622) of GRB 230414B (D'Ai et al., GCN 33612) with the
Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a
single r-band image obtained on 2023 Apr 14.95 UT (6.57 hr after the
GRB), we clearly detect the optical afterglow at a magnitude r = 19.42
+- 0.02 (AB), calibrated against nearby stars from the Pan-STARRS catalog.
Comparing to earlier magnitudes from the above mentioned GCNs, our
measurement indicates a slow decay or plateau phase, as already hinted
by the magnitudes reported by Moskvitin et al. (GCN 33622).
GCN Circular 33622
Subject
GRB 230414B: SAO RAS optical observations
Date
2023-04-14T22:41:49Z (4 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. S. Moskvitin (SAO RAS) and V. P. Goranskij (SAI, Moscow University)
report on behalf of a larger collaboration:
We observed the field of GRB 230414B detected by Swift
(D'Ai et al., GCN 33612) with the SAO RAS 1-m telescope
Zeiss-1000 + CCD photometer. We obtained several images in Rc band.
The GRB OT (Pankov et al., GCN 33615; Lu et al., GCN 33616;
Raman et al., GCN 33618; Ghosh et al., GCN 33620) is clearly detected
in the stacked frame with the brightness of R = 19.8 +/- 0.1
(T_mid - T0 = 3.68 hours). This preliminary photometry is based on R2
magnitudes of nearby USNO-B1 stars. The OT magnitude is not corrected
for the Galactic extinction.
GCN Circular 33621
Subject
GRB 230414B: Enhanced Swift-XRT position
Date
2023-04-14T21:53:00Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 940 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 230414B, 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 = 181.09469, +53.15434 which is equivalent
to:
RA (J2000): 12h 04m 22.73s
Dec (J2000): +53d 09' 15.6"
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 Circular 33620
Subject
GRB 230414B: 1.3m DFOT Optical observations
Date
2023-04-14T20:31:18Z (4 years ago)
From
Ankur Ghosh at ARIES <ghosh.ankur1994@gmail.com>
Ankur Ghosh, Dimple, Kuntal Misra, Rahul Gupta, Amit K Ror, Amar Aryan, and
Shashi B. Pandey (ARIES) report:
We observed the field of GRB 230414B detected by *Swift* (D'Ai et al. 2023,
GCN 33612) using the 1.3m Devasthal Fast Optical Telescope (DFOT) located
at the Devasthal observatory of Aryabhatta Research Institute of
Observational Sciences (ARIES), Nainital, India. We have taken multiple
frames with an exposure time of 300 seconds in several passbands. We
clearly detected the GRB afterglow within the enhanced *Swift*-XRT error
circle (Evans et al. 2023, GCN 33613) in each image. The estimated
preliminary magnitude is the following:
Date_Start_UT T_start-T0 (days) Filter Exp time (sec)
magnitude
==============================================================
2023-04-14 17:13:30 ~ 0.041 R 300
20.06 +/- 0.06
The detection of the GRB afterglow is consistent with Lu et al. 2023, GCN
33616, Pankov et al. 2023, GCN 33617, and Raman et al. 2023, GCN 33618.
The magnitude is not corrected for the Galactic and host extinction in the
direction of the GRB afterglow. Photometric calibration is performed using
the standard stars from the USNO-B1.0 catalog.
GCN Circular 33618
Subject
GRB 230414B: GROWTH India Telescope afterglow confirmation
Date
2023-04-14T17:56:54Z (4 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
D. Raman (IITB), A. Suresh (IITB), V. Swain (IITB), H. Kumar (IITB), G. Waratkar(IITB), V. Bhalerao (IITB), G.C. Anupama(IIA), S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of GRB 230414B detected by Swift ( A. D'Ai et al., GCN 33612) with 0.7m GROWTH-India Telescope (GIT). GIT automatically triggered at 16:17:41 UT, i.e., 3.3 min after the Swift/BAT trigger. We obtained frames in the r' and i' band of 120 sec each. We detected an uncatalogued source at RA 12:04:22.65, Dec: 53:09:15.4 with an uncertainty of 1.9 arcsec. There is no minor planet present at this position. The photometric results follow as:
----------------------------------------------------------------------
JD (mid) | T_mid-T0 (min) | Filter | Magnitude (AB) |
----------------------------------------------------------------------
2460049.18505852 | 12.13 | r' | 19.45 +/- 0.08 |
2460049.18674811 | 14.56 | r' | 19.47 +/- 0.08 |
2460049.19372952 | 24.62 | r' | 19.91 +/- 0.09 |
2460049.18854398 | 17.15 | i' | 19.08 +/- 0.13 |
----------------------------------------------------------------------
The results are consistent with (T.H. Lu et al., GCN #33616; N. Pankov et al., GCN #33617).We encourage photometric for further confirmation and spectroscopic follow-up for redshift measurement. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT; Kumar et al. 2022) 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 the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular 33617
Subject
GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
Date
2023-04-14T17:27:27Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI)
report on behalf of GRB IKI FuN:
The correct name of GRB in the GCN 33615 should be 230414B.
We apologize for possible inconvenience.
GCN Circular 33616
Subject
GRB 230414B: Nanshan/HMT optical afterglow detection
Date
2023-04-14T17:26:09Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
T.H. Lu (NAOC), Z.P. Zhu (NAOC, HUST), S.Y. Fu, S.Q. Jiang, X. Liu, D.
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 230414B detected by Swift (A. D'Ai et al.,
GCN 33612) using the HMT-0.5m telescope located at Nanshan, Xinjiang,
China. Observations started at 16:19:34 UT on 2023-04-14, i.e., 313s
after the Swift/BAT trigger, and a series of 20 s, 40 s, 60 s, 90 s
exposures have been obtained without any filter. Observations are still
ongoing.
We detected an uncatalogued and varying optical transient (OT) at
coordinates
R.A. (J2000) = 12:04:22.70
Dec.(J2000) = +53:09:16.38
with an uncertainty of ~ 0.5 arcsec, and it has m(r) ~19.3 mag in the
co-added image from the initial exposures, calibrated with the nearby
PanSTAR field in the Sloan r-filter. We thus think that the OT is the
optical afterglow of the burst.
GCN Circular 33614
Subject
Swift GRB 230414B: Global MASTER-Net observations report
Date
2023-04-14T16:50:47Z (4 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 230414B ( A. D'Ai et al., GCN 33612) errorbox 1644 sec after notice time and 1703 sec after trigger time at 2023-04-14 16:42:44 UT, with upper limit up to 16.1 mag. Observations started at twilight. The observations began at zenith distance = 32 deg. The sun altitude is -9.8 deg.
The galactic latitude b = 63 deg., longitude l = 138 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2210174
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
1793 | MASTER-Kislovodsk | C | 180 | 16.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 33613
Subject
GRB 230414B: Prompt enhanced Swift-XRT position
Date
2023-04-14T16:50:41Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 230414B, we find an
enhanced XRT position of the afterglow: RA, Dec: 181.09439, 53.15428
which is equivalent to:
RA (J2000) = 12 04 22.65
Dec (J2000) = +53 09 15.4
with an uncertainty of 1.9 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/1164180.
Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular 33612
Subject
GRB 230414B: Swift detection of a burst
Date
2023-04-14T16:27:28Z (4 years ago)
From
Antonino D'Ai at IASF-PA <antonino.dai@inaf.it>
A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB) and M. A. Williams (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:
At 16:14:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230414B (trigger=1164180). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 181.071, +53.127 which is
RA(J2000) = 12h 04m 17s
Dec(J2000) = +53d 07' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 30 sec. The peak count rate
was ~400 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 16:16:29.8 UT, 128.6 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 181.09569, 53.15401 which is equivalent
to:
RA(J2000) = 12h 04m 22.97s
Dec(J2000) = +53d 09' 14.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 110 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. We cannot determine whether the source
is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.68 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.8
(+2.36/-2.05) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 133 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 none of
the XRT error circle. 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 expected
extinction corresponding to E(B-V) of 0.017.
Burst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.it).
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/)