GRB 240205B
GCN Circular 35708
Subject
GRB 240205B: PRIME near infrared detection
Date
2024-02-08T21:36:03Z (2 years ago)
From
Joe Durbak at UMD <gcn.joedurbak@gmail.com>
Via
Web form
O. Guiffreda (UMD), J. Durbak (UMD), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC)
Following the FERMI GBM detection (GCN 35682), and Swift BAT detection (Moss et al. GCN 35683), we observed the transient field in the J filter with PRIME ~2 days after FERMI & Swift detection.
At the position of the optical counterpart reported by MASTER (Lipunov et al. GCN 35684) and Skynet (Dutton et al. GCN 35687), we detect an uncatalogued source in J band. Using nearby 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:
Filter | Mag(AB) | SNR | Seeing | Total exposure time (s)
-------|----------------|-----|--------|-------------------------
J | 19.65 +/- 0.15 |11.8 | 2.138” | 800
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa.
Further observations are planned.
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
GCN Circular 35704
Subject
GRB 240205B: AstroSat CZTI detection
Date
2024-02-08T15:28:38Z (2 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>
Via
Web form
J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240205B which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35682), Swift-BAT (Moss et al., GCN Circ. 35683), and GECAM (Zhang et al., GCN Circ. 35689).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-02-05 22:13:46.50 UTC. The measured peak count rate associated with the burst is 731 (+51, -56) counts/s above the background in the combined data of all quadrants, with a total of 3027 (+294, -448) counts. The local mean background count rate was 295 (+3, -2) counts/s. Using cumulative rates, we measure a T90 of 43 (+3, -2) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-02-05 22:13:45.31 UTC. The measured peak count rate associated with the burst is 632 (+69, -74) counts/s above the background in the combined data of all quadrants, with a total of 2944 (+573, -674) counts. The local mean background count rate was 1220 (+4, -6) counts/s. We measure a T90 of 42 (+2, -3) s from the cumulative Veto light curve.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 35702
Subject
GRB 240205B: Swift-BAT refined analysis
Date
2024-02-07T19:18:03Z (2 years ago)
From
Sibasish Laha at GSFC <sibasish.laha@nasa.gov>
Via
email
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), T. Sakamoto (AGU),
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240205B (trigger #1213095)
(Moss, et al., GCN Circ. 35683). The BAT ground-calculated position is
RA, Dec = 351.466, -55.123 deg which is
RA(J2000) = 23h 25m 51.9s
Dec(J2000) = -55d 07' 24.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.
The BAT light curve shows a complex structure with a duration of ~ 60 sec.
Above 100 keV, the lightcurve is dominated by a single bright 1 s long peak around T+40.
A similar feature has also been reported by GECAM-B telescope, Zhang et al., GCN circ. 35689.
T90 (15-350 keV) is 47.29 +- 0.29 sec (estimated error including systematics).
The time-averaged spectrum from T-0.84 to T+78.94 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.23 +- 0.03. The fluence in the 15-150 keV band is 2.6 +- 0.0 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+39.07 sec in the 15-150 keV band
is 47.8 +- 1.0 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/1213095/BA/
GCN Circular 35701
Subject
Konus-Wind detection of GRB 240205B (long / very soft)
Date
2024-02-07T17:14:19Z (2 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
Via
legacy email
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 240205B (Fermi GBM observation:
Fermi GBM team, GCN 35682; Fletcher et al., GCN 35693;
Swift detection: Moss et al., GCN 35683;
GECAM detection: Zhang et al., GCN 35689;
CALET detection: Sakamoto et al., GCN 35697)
triggered Konus-Wind (KW) at T0=79986.680 s UT (22:13:06.680).
The burst light curve shows multiple overlapping pulses
in the interval from ~T0-5 s to ~T0+57 s,
with the brightest peak around ~T0+36 s.
The emission is seen up to ~1 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240205_T79986/
As observed by Konus-Wind, the burst had
a total fluence of (3.22 ± 0.18)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0+36.352 s,
of (7.38 ± 0.87)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
A time-integrated spectrum (measured from T0 to T0+49.408 s)
is best fit in the 20 keV - 1.5 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.80 (-0.08,+0.09),
the high energy photon index beta = -3.20 (-6.80,+0.35),
the peak energy Ep = 27 (-16,+10) keV,
chi2 = 28/49 dof.
A spectrum near the peak count rate (measured from T0+33.024 to T0+41.216 s)
is best fit in the 20 keV - 15 MeV range by a CPL model
with alpha = -1.70(-0.10,+0.11) and Ep = 49(-10,+8) keV (chi2 = 64/62 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -3.5 (chi2 = 64/62 dof).
Assuming the redshift z=0.824 (Fausey et al., GCN 35698)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the burst isotropic energy release E_iso to (6.1 ± 0.3)x10^52 erg,
the isotropic peak luminosity L_iso to (2.6 ± 0.5)x10^52 erg/s,
the rest-frame peak energy of the time-integrated spectrum Ep,i,z to ~49 keV,
and the rest-frame peak energy at the peak of the emission Ep,p,z to ~89 keV.
With the obtained estimates, GRB 240205B is a soft-spectrum outlier in
both 'Amati' and 'Yonetoku' relations derived for the sample of >300 long
KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB240205_T79986/GRB240205B_rest_frame.pdf
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 35698
Subject
GRB 240205B: VLT/X-shooter redshift
Date
2024-02-07T11:08:25Z (2 years ago)
From
J. T. Palmerio at Observatoire de Paris - GEPI <jesse.palmerio@obspm.fr>
Via
Web form
H. Fausey (GWU), J. T. Palmerio (GEPI/Obs. de Paris & IAP), D. B. Malesani (DAWN/NBI & Radboud Univ.), A. Saccardi (GEPI/Obs. de Paris), L. Izzo (INAF-OACn & DARK/NBI), V. D'Elia (SSDC & INAF-OAR), J. P. U. Fynbo (DAWN/NBI), A. Martin-Carrillo (UCD, Ireland), A. J. Levan (Radboud), N. R. Tanvir (U. Leicester), B. Gompertz (Birmingham) report on behalf of the Stargate collaboration:
We observed the field of GRB 240205B detected by Fermi-GBM (Fermi GBM Team, GCN 35682), Swift-BAT (Moss et al., GCN 35683), and GECAM (Zhang et al., GCN 35689) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 AA, and consist of 2 exposures of 600 s each. The observation starting-time was 00:21:26 UT on 2024 Feb 7 (~26 hr after the trigger). Observations were carried out in twilight, at high airmass 2.3 to 2.5.
Despite the low elevation, in a single r-band image taken with the acquisition camera, we clearly detect the optical afterglow (Lipunov et al., GCN 35684; Fernandez-Garcia et al., GCN 35686; Dutton et al., GCN 35687; Ferro et al., GCN 35694; Fernandez-Garcia et al., GCN 35696). We measure r' = 19.05 +/- 0.07 (AB) calibrated against two nearby SkyMapper stars.
In a preliminary reduction of the spectra, we detect a continuum down to at least 3200 AA implying z < 1.6 from the lack of damped Lyman-alpha absorption. Multiple absorption features are detectd, consistent with being due to Fe II and Mg II at a common redshift z = 0.824. While the modest S/N does not allow to identify any fine-structure lines at this redshift, due to the lack of unidentified features we consider z = 0.824 the likely redshift of GRB 240205B.
We acknowledge the excellent support from the ESO staff in Paranal in conducting such a challenging observation, in particular Boris Haeussler, Zahed Wahhaj, and Diego Parraguez.
GCN Circular 35697
Subject
GRB 240205B: CALET Gamma-Ray Burst Monitor detection
Date
2024-02-07T01:32:14Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
T. Sakamoto, A. Yoshida, S. Sugita (AGU), Y. Kawakubo (LSU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 240205B (Fermi GBM Final Real-time Localization:
Fermi GBM team, GCN Circ. 35682; Swift detection: Moss et al.,
GCN Circ. 35683; INTEGRAL SPI-ACS Trigger #10513; GECAM
detection: Zhang et al., GCN Circ. 35689; Fermi GBM Observation:
Fletcher et al., GCN Circ. 35693) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 22:13:45.98 UTC on 5 February 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1391206207/).
The burst signal was seen by only the SGM detector.
Based on the GRB position reported by Swift-BAT (referenced to
GCN Circ. 35683), the angle from the SGM bore-sight is 106
degrees, and the direction was blocked by the structures of the
International Space Station. Although the observed light curve was
affected by the structures, SGM detected the brightest peak which
was observed by Fermi-GBM, INTEGRAL SPI-ACS, and GECAM.
The burst light curve shows a single pulse that starts at T+0.0 sec,
peaks at T+0.4 sec, and ends at T+0.9 sec. The T90 and T50 durations
measured by the SGM data are 0.7 +/- 0.3 sec and 0.2 +/- 0.1 sec
(40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1391206207/index.html
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 35696
Subject
GRB 240205B: BOOTES-6 optical afterglow follow-up
Date
2024-02-06T23:51:09Z (2 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Via
legacy email
E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, S. Guziy, S.-Y. Wu, I. Olivares, R. Sanchez-Ramirez and A. J. Castro-Tirado (IAA-CSIC, Granada), Y.-D. Hu (INAF-OAB Brera), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), A. Castellon, S. Castillo, A. J. Reina and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:
Following the detection of GRB 240205B by Fermi (GCNC 35682, Fletcher et al. GCNC 35693), Swift (Palmer et al., GCNC 35683), INTEGRAL_SPIACS (trig# 10513), CALET/GBM (trig# 1391206207) and GECAM (Zhang et al., GCNC 35689), the 0.6m BOOTES-6/DPR robotic telescope at Boyden Observatory (South Africa) continued the observation of this burst, starting on Feb 6 at 18:13 UT (i.e. ~20 h after trigger), as part of the monitoring conducted by the BOOTES Global Network of Robotic Telescopes. Images were gathered in different optical bands (griz). The optical afterglow (Lipunov et al. GCNC 35684, Fernandez-Garcia et al. GCNC 35686, Dutton et al. GCNC 35687, Ferro et al. GCNC 35694) is still detected in all filters. We measure a g-band mag of 18.1 ± 0.1 (on a 300s image taken at 18:30 UT). Spectroscopic observations, in spite of the low elevation of the target after sunset, are encouraged.
We thank the staff at Boyden Observatory for their excellent support.
GCN Circular 35695
Subject
GRB 240205B: ATCA detection of radio counterpart
Date
2024-02-06T22:54:29Z (2 years ago)
From
Sarah Chastain at University of New Mexico <sarahichastain@gmail.com>
Via
Web form
S. Chastain (UNM), G. E. Anderson (Curtin), A. Gulati (USyd), L. Rhodes (Oxford), J. K. Leung (UofT/HUJI),
A. J. van der Horst (GWU) on behalf of the PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) performed rapid-response follow-up to long GRB 240205B detected by Fermi-GBM (Fermi GBM Team, GCN 35682), Swift-BAT (Moss et al., GCN 35683), and GECAM (Zhang et al., GCN 35689) at the MASTER-OT localization (Lipunov et al., GCN 35684) as part of the Large ATCA "PanRadio GRB" follow-up programme C3542 (PI. Anderson).
The observation was on target by 2024-02-05 at 22:26 UT and ended 11.5 hours later. We detected a candidate radio afterglow at 9 GHz consistent with the MASTER-OT position with a preliminary flux density of ~100 microJy with rms noise of 11 microJy.
Further observations are planned.
We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
GCN Circular 35694
Subject
GRB 240205B: REM detection of the optical/NIR afterglow
Date
2024-02-06T16:33:01Z (2 years ago)
From
Matteo Ferro <matteo.ferro@inaf.it>
Via
Web form
M. Ferro, R. Brivio, Y.-D. Hu, P. D'Avanzo, D. Fugazza, S. Covino (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 240205B (Fermi GBM Team., GCN 35682; Moss et al., GCN 35683) with the REM 60cm robotic telescope located at the ESO Observatory of La Silla (Chile). The observations were carried out in the g, r, i, z, J, H and K bands, starting on 2024 Feb 05 at 00:46:23 UT (i.e. about 2.55 hours after the GBM and Swift trigger) and lasted for about 1.5 hours.
The optical (Lipunov et al., GCN 35684, Fernandez-Garcia et al., GCN 35686, Dutton et al., GCN 35687) and NIR afterglow is detected in our observations. From preliminary photometry, we derive the following magnitudes, in r and H bands:
r = 15.67+/-0.01 (AB; calibrated against SkyMapper catalogue)
at a mid time of t-t0 ~ 2.63 hours after the GRB trigger.
H = 13.92+/-0.04 (Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 ~ 2.65 hours after the GRB trigger.
GCN Circular 35693
Subject
GRB 240205B: Fermi GBM Observation
Date
2024-02-06T15:05:19Z (2 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
Via
Web form
C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 22:13:08.17 UT on 05 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240205B (trigger 728863993/240205926).
which was also detected by Swift BAT (M. J. Moss et al. 2024, GCN 35683) and GECAM (W. Zhang et al. 2024, GCN 35689).
The Fermi GBM Real-time Final Localization (GCN 35682) is consistent with the Swift BAT position.
This burst was also independently detected by INTEGRAL SPI-ACS.
The angle from the Fermi LAT boresight is 112 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 47 s (50-300 keV). The time-averaged spectrum
from T0-3.3 to T0+54.0 s is best fit by
a Band function with Epeak = 34 +/- 0.8 keV,
alpha = -1.69 +/- 0.02, and beta = -2.78 +/- 0.08.
The event fluence (10-1000 keV) in this time interval is
(4.77 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+38 s in the 10-1000 keV band is 81.2 +/- 0.9 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 35689
Subject
GRB 240205B: GECAM detection of a long burst
Date
2024-02-06T03:12:10Z (2 years ago)
From
wenlongzhang2018@163.com
Via
Web form
Wen-Long Zhang, Shao-Lin Xiong, Chen-Wei Wang report on behalf of the GECAM team:
GECAM-B was triggered in-flight by a long burst, GRB 240205B, at 2024-02-05T22:13:08.400 UTC (T0), which was also detected by Fermi/GBM (GCN #35682), Swift/BAT (GCN #35683), INTEGRAL_SPIACS (trig# 10513) and CALET/GBM (trig# 1391206207). As the science data arrived, GECAM-B was also triggered on-ground by this burst with the automatic processing pipeline.
According to the GECAM-B light curves, this burst shows multi-pulses with a total duration of ~50 sec. Interestingly, we note that there is a bright and narrow peak at T0+ 37.5 s.
According to the in-flight software, GECAM-B localized this burst to the following position (J2000):
Ra: 344.14 deg
Dec: -53.02 deg
Err: 8.74 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Swift/BAT and Fermi/GBM within the error.
We note that these results are very preliminary. Refined analysis will be reported later.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in December 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular 35687
Subject
GRB 240205B: Skynet Optical Afterglow Observations
Date
2024-02-06T02:25:46Z (2 years ago)
From
Dylan Dutton at UNC Chapel Hill <ddutton59@gmail.com>
Via
Web form
Dylan Dutton, Donovan Schlekat, Logan Selph, Ruide Fu, Megan Dubay, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill.
We observed the field of GRB 240205B with our 0.4m robotic telescopes located in the Cerro Tololo Inter-American Observatory, Chile. The observation began at 00:42:54 UTC on Feb 05 2024, approximately 2.5 hours after the trigger reported by Fermi (GCN 35682) and SWIFT (Palmer et al., GCN 35683).
We obtained multiple exposures in the B, V, R, and I filters. Exposure lengths were calculated using our automated exposure length scaling model.
We clearly detect the optical afterglow reported by MASTER (Lipunov et al., GCN 35684) and BOOTES-7 (GCN 35686). The coordinates are within the uncertainty radius of the Swift localization and consistent with the coordinates reported by MASTER (Lipunov et al., GCN 35684):
R.A. (J2000): 23:25:50.12
Dec. (J2000): -55:07:05.5
We report the photometry below. We estimate a spectral index of -1.
ExpLen | Filter | Mag | Mag Error | MJD
------------------------------------------------
223.98 | B | 16.12 | 0.017 | 60346.030
284.45 | B | 16.12 | 0.017 | 60346.031
233.30 | V | 15.74 | 0.009 | 60346.032
100.85 | R | 15.49 | 0.010 | 60346.034
298.28 | V | 15.86 | 0.009 | 60346.035
145.94 | R | 15.66 | 0.011 | 60346.048
265.82 | B | 16.31 | 0.012 | 60346.049
113.75 | I | 15.33 | 0.019 | 60346.049
272.02 | V | 15.94 | 0.008 | 60346.052
131.13 | R | 15.76 | 0.010 | 60346.065
391.41 | V | 16.11 | 0.008 | 60346.065
Our images have been calibrated using stars from the APASS catalog.
GCN Circular 35686
Subject
GRB 240205B: BOOTES-7 optical afterglow follow-up
Date
2024-02-06T01:23:45Z (2 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Via
legacy email
E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia, S.-Y. Wu, S. Guziy (IAA-CSIC Granada), Y.-D. Hu (INAF-OAB, Brera), L. Hernandez-Garcia (Univ. de Valparaiso), C. Perez del Pulgar, A. Castellon, A. Reina (Univ. de Malaga), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), report:
Following the detection of GRB 240205B by Fermi (GCNC 35682) and Swift (Palmer et al., GCNC 35683), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) pointed to the burst position starting on Feb 6 at 00:15 UT (i.e. ~2 h after trigger). Images are being gathered, through passing clouds, in different optical bands (griz). In any case, the optical afterglow reported by MASTER (Lipunov et al. GCNC 35684), is well detected in all images, for which we measure a g-band mag of 15.5 +/- 0.1 (on a 60s image taken at 00:33 UT). Spectroscopic observations are encouraged.
We thank the staff at San Pedro de Atacama Celestial Explorations observatory for their excellent support.
GCN Circular 35684
Subject
GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
Date
2024-02-05T23:02:28Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V.Lipunov, Ya.Kechin, N.Tiurina, G.Antipov E.Gorbovskoy (Lomonosov MSU), D.Buckley (SAAO),
D.Svinkin (Ioffe Institute, Konus-Wind),
Ya.Kechin, K.Zhirkov, A.Kuznetsov, D.Vlasenko, P.Balanutsa, Yu.Tselik, N.Tiurina, I.Gorbunov, V.Vladimirov,
D.Zimnukhov, V.Senik, A.Yudin,A.Chasovnikov, D.Cheryasov, A.Sosnovskij (Lomonosov MSU,SAI,PhysicsDepartment),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
C.Francile. F. Podesta, R.Podesta (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L) started Swift GRB 240205B/Fermi GRB 240205B observation 26 sec after notice time and 47 sec after trigger time at 2024-02-05 22:13:54 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 86 deg. (Lipunov et al. GCN 35681) MASTER auto-detection system discovered changing OT inside Swift BAT (Moss GCN 35682, Fermi GCN 25682)
MASTER OT J232550.14-550704.6
R.A.,Dec(2000)=23 25 50.14 -55 07 04.6 with mOT~12.8 near maximum
GCN Circular 35683
Subject
GRB 240205B: Swift detection of a burst
Date
2024-02-05T22:31:07Z (2 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
M. J. Moss (GSFC), C. Gronwall (PSU), J.D. Gropp (PSU),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 22:13:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240205B (trigger=1213095). Swift did not immediately slew
due to a Sun constraint.
The BAT on-board calculated location is
RA, Dec 351.476, -55.132 which is
RA(J2000) = 23h 25m 54s
Dec(J2000) = -55d 07' 55"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve is only available
up to T+8s due to a telemetry gap. The partial light curve shows a
complex rise to a count rate of ~10,000 counts/s (15-350 keV)
and still rising steeply at 8 sec after the trigger.
This GRB is Sun constrained for Swift observations until February 25th.
There will therefore not be any XRT or UVOT data collected.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 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 Circular 35682
Subject
GRB 240205B: Fermi GBM Final Real-time Localization
Date
2024-02-05T22:23:35Z (2 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 22:13:08 UT on 5 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240205B (trigger 728863993.169242 / 240205926).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 352.0, Dec = -53.0 (J2000 degrees, equivalent to J2000 23h 27m, -53d 00'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 110.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_skymap_all_bn240205926.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_healpix_all_bn240205926.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_lc_medres34_bn240205926.gif