EP250215a, GRB 250215A
GCN Circular 39375
Subject
Konus-Wind detection of GRB 250215A / EP250215a
Date
2025-02-19T15:45:03Z (10 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 250215A / EP250215a
(Fermi-GBM detection: The Fermi GBM team, GCN 39327;
Scotton and Meegan, GCN 39342;
EP-WXT detection: Wang et al., GCN 39329;
INTEGRAL-SPI-ACS detection: Barria et al., GCN 39331;
AstroSat-CZTI detection: Tembhurnikar et al., GCN 39334;
SVOM/GRM detection: Zheng et al., GCN 39335)
triggered Konus-Wind at T0=09130.387 s UT (02:32:10.387).
The burst light curve shows a multipeaked structure
which starts at ~T0-14 s and has a total duration of ~22 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/GRB250215_T09130/
As observed by Konus-Wind, the burst
had a fluence of 8.33(-1.97,+2.51)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.054 s,
of 5.12(-1.37,+1.66)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
Since a major part of the burst emission was detected
before the trigger time and the burst shows a minor spectral evolution,
we use the spectrum measured from T0 to T0+8.448 s
to estimate the total burst fluence.
This spectrum is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.03(-0.54,+0.69),
the high energy photon index beta = -2.31(-1.22,+0.30),
the peak energy Ep = 130(-36,+80) keV
(chi2 = 80/97 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.14(-0.74,+3.47),
the high energy photon index beta = -2.35(-0.68,+0.29),
the peak energy Ep = 118(-51,+53) keV
(chi2 = 18/17 dof).
Assuming the redshift z=4.61 (Sanchez-Ramirez et al., GCN 39343)
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 following rest-frame parameters:
the isotropic energy release E_iso is 3.35(-0.79,+1.01)x10^53 erg,
the peak luminosity L_iso is 1.15(-0.31,+0.37)x10^54 erg/s,
the rest-frame peak energy of the time-averaged spectrum
Ep,i,z is 660(-250,+298) keV.
With the obtained estimates, GRB 250215A is inside 68% prediction band for
the 'Amati' and 90% - for the '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/GRB250215_T09130/GRB250215A_rest_frame.pdf
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.
GCN Circular 39366
Subject
GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
Date
2025-02-18T17:28:03Z (a year ago)
From
Remo Ruffini at ICRA <ruffini@icra.it>
Via
Web form
R. Ruffini, D. Berkimbayev, G. Vereshchagin, R. F. Mohideen Malik, N. Shynggyskhan, M.T. Mirtorabi, J.A. Rueda, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report:
GRB 250215A / EP250215A was detected by Fermi (GCN 39327), Einstein Probe (GCN 39329), and SVOM (GCN 39333) at a redshift of z = 4.61 (GCN 39343). The burst duration is 2.3 s in the rest frame, corresponding to T_{90} = 13.4 s in the observer's frame (GCN 39342). The isotropic energy release is 3 \times 10^{53} erg, consistent with a BdHN I classification. This event shares similarities with GRB 220101A (GCN 37964), GRB 221009A (GCN 32828), and GRB 240825A (GCN 37536). Extended follow-up multi-wavelength observations are encouraged to fully characterize the BdHN I episodes: optical data for pulsar identification, X-ray observations to track the afterglow evolution, and GeV measurements to constrain the black hole energy.
GCN Circular 39353
Subject
GRANDMA/OPD observations of GRB250215A
Date
2025-02-17T12:20:03Z (a year ago)
From
Nidhal Guessoum at AUS, UAE <nguessoum@aus.edu>
Via
Web form
Leandro de Almeida (LNA), Nélio Sasaki (UEA-Parintins), Wagner Corradi (LNA), Felipe Navarete (LNA), Martin Masek (FZU), Nuha Manal Pattani (AUS), Shaikha Alshamsi (AUS), S. Antier (OCA/IJCLAB), P. Hello (IJCLAB), N. Guessoum (AUS), C. Andrade, M. Coughlin (UMN), P-A Duverne (APC), S. Karpov (FZU), T. Pradier (Unistra/IPHC), and D. Turpin (CEA-Saclay/Irfu), on behalf of Observatório do Pico dos Dias (OPD/LNA/Brazil) and the GRANDMA collaboration, began observations of GRB 250215A, initially detected by the Fermi GBM Team (GCN 39327).
Based on the coordinates of the field center (RA=10:25:19.48, DEC=-27:41:54.00), we obtained 12 frames of 300 seconds each using the 0.6m telescope of OPD, starting on 2025-02-16 at 02:30:42.23 and ending at 07:43:29.39 UTC. The FOV of the stacked image is 10.5x10.5 arcmin with a pixel scale of 0.614 arcsec/pixel.
We did not detect any candidate in our stacked images with an upper limit of I > 21.34 mag at 5-sigma, calibrated against several stars of the I/339 catalog (HSOY, Altmann et al, 2017).
Our non-detection upper limit is similar to the results of Ducoin et al. (GCN 39344) with nothing brighter than 22.7 mag detected in r. Our results are also in slight discrepancy with the findings of Malesani et al. (GCN 39341).
GRANDMA is a worldwide telescope network (http://grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518).
GCN Circular 39348
Subject
GRB 250215A / EP250215a: LCO detection of the afterglow
Date
2025-02-16T21:11:38Z (a year ago)
From
Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>
Via
Web form
I. Pérez-Fournon, F. Poidevin, D. Aguado, J.A. Acosta-Pulido, A. López-Oramas, D. Nespral (IAC and ULL), F. Acero (CEA Saclay and IAC), N.C. Sun (UCAS), W. Li, Y. Wang, Z. Niu (NAOC), D. Cano-Morales, I. Correa-Plasencia, and A.E. Hernández-Díaz (ULL)
We observed the field of the Fermi long GRB 250215A (Fermi GBM Team, GCN Circ. 39327), detected also by Einstein Probe WXT and FXT (EP250215a, Wang et al., GCN Circ. 39329), INTEGRAL SPI-ACS (Barria et al., GCN Circ. 39331), AstroSat CZTI (Tembhurnikar et al., GCN Circ. 39334), SVOM/GRM (Zheng et al., GCN Circ. 39335), and Swift XRT (Page et al., GCN Circ. 39336) with the two Las Cumbres Observatory Global Telescope network (LCOGT) 1-m telescopes, equipped with Sinistro cameras, at the LCOGT node at the Siding Spring Observatory (Australia). We obtained two 600-sec exposures in the SDDS-i' filter starting at 2025-02-15 11:08:48 and 12:58:59 UT, respectively. The optical afterglow detected first by Liu et al. (GCN Circ. 39330) at a redshift of z = 4.61 (Sánchez-Ramírez et al., GCN Circ. 39343)
is clearly detected in our LCOGT images with magnitudes of i' = 20.10 +/- 0.15 in the first observation (starting 8.615 after the trigger) and i' = 20.59 +/- 0.23 in the second one (starting 10.451 hr after trigger), with a clear fading between the two observations. The photometry has been
calibrated against Pan-STARRS DR2 and is not corrected for Galactic extinction. These results are consistent with other optical detections of the afterglow (Liu et al., GCN Circ. 39330; Xie et al., GCN Circ. 39333; Malesani et al., GCN Circ. 39339; and Malesani et al. GCN Circ. 39341).
This work makes use of observations from the Las Cumbres Observatory global telescope network (LCOGT observing programme IAC2025A-009, SGLF).
GCN Circular 39345
Subject
GRB 250215A: Swift/UVOT Upper Limits
Date
2025-02-16T15:30:21Z (a year ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
Via
Web form
M.H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 250215A detected by Fermi,
the Einstein Probe and INTEGRAL (GCN Circ. 39327; Wang et al., GCN Circ. 39329; Barria
et al., GCN Circ. 39331) 19.5 ks after the trigger. The afterglow reported in the XRT
(Page et al., GCN Circ. 39336) and optical/IR (Liu et al., GCN Circ. 39330; Xie et al.,
GCN Cic. 39333; Malesani et al., GCN Circ. 39339) is not detected in the single U-band
exposure. This is consistent with the redshift of z=4.61 reported by Sanchez-Ramirez
et al. (GCN Circ. 39343).
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011,
AIP Conf. Proc. 1358, 373) for the initial exposure is:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 9504 16104 1704 >21.06
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening
of E(B-V) = 0.056 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 39344
Subject
GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
Date
2025-02-16T14:01:44Z (a year ago)
From
Alan Watson at UNAM <alan@astro.unam.mx>
Via
Web form
Jean-Grégoire Ducoin (CPPM), Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Noémie Globus (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Sarah Antier (OCA), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Kin Ocelotl López (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), and Benjamin Schneider (LAM) report:
We imaged the field of GRB 250215A (Fermi GBM Team, GCN Circ. 39327, Barria et al., GCN Circ. 39331, Zheng et al., GCN Circ. 39335), originally detected as EP250215a (Wang et al., GCN Circ. 29329), with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico.
We observed from 2025-02-16 05:37 UTC to 10:18 UTC (1.13 to 1.32 days after the trigger) and obtained 200 minutes of exposure in the r filter at high airmass. The data were coadded with the COLIBRÍ pipeline and analyzed in STDWeb/STDPipe (Karpov 2021), with photometric calibration against Pan-STARRS DR1 and image subtraction against Pan-STARRS DR2. Our photometry is not corrected for Galactic extinction.
At the position of the OT reported by Liu et al. (GCN Circ. 39330), we do not detect a point source to an estimated 3-sigma upper limit of
r > 22.7
Our non-detection is in contrast to the slightly earlier detection at i ≈ 21.3 reported by Malesani et al. (GCN Circ. 39341). In retrospect, this is not unexpected, given the bandpass of our filter from 553-695 nm and the presence of Ly-alpha absorption below 682 nm due to the source redshift of 4.61 (Ramírez-Sánchez et al., GCN Circ. 39343).
Our limiting magnitude is consistent with the limit in r reported by Liu et al. (GCN Circ. 39327), assuming a temporal decay index of approximately 0.9, estimated from the Gemini and NOT detections in i reported by Malesani et al. (GCN Circ. 39339 and 39341).
We warmly thank the COLIBRÍ and DDRAGO engineering teams and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir.
GCN Circular 39343
Subject
EP250215a / GRB 250215A : GTC redshift z = 4.61
Date
2025-02-16T11:58:30Z (a year ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Via
email
R. Sanchez-Ramirez, A. J. Castro-Tirado, M. D. Caballero-Garcia, S.
Guziy, G. Garcia-Segura, I. Perez-Garcia and S.-Y. Wu (IAA-CSIC), M.
Gritsevich (Univ. of Helsinki), D. Xu (NOAC), A. Martin-Carrillo (UCD),
Y.-D. Hu (GXU), S.B. Pandey (UPSO), S. Geier and A. Cabrera-Lavers
(GTC), on behalf of a larger collaboration, report:
Following the detection of EP250215a/GRB250215A by EP/WXT (Wang et al.
GCNC 39329), INTEGRAL/SPI-ACS (Barria et al. GCNC 39331), AstroSat CZTI
(Tembhurnikar et al. GCNC 39334) SVOM/GRM (Zheng et al., GCN 39335)
and Fermi/GBM (Scotton and Meegan, GCNC 39342), we triggered the 10.4m
GTC in Observatorio del Roque de Los Muchachos (La Palma, Spain) in
order to get an spectrum of the proposed optical afterglow detected by
NOT (Liu et al., GCNC 39330, Malesani et al., GCNC 39341), SVOM/VT (Xie
et al., GCN 39333) and Gemini-South (Malesani et al., GCNC 39339).
Data was gathered starting on Feb 16, 2:27 UT (i.e. 23.9 hr post-
burst), consisting of 4x1000s spectra with the R1000R grism, covering
the range 5,200-10,000. Based on a preliminary reduction, we detect a
prominent Ly-alpha absoption at ~6820A, plus several metal features
interpreted as being due to SiII, CII, SiIV and CIV at a redshift of z
= 4.61, wich we proposed to be the redshift of EP250215a/GRB250215A.
GCN Circular 39342
Subject
GRB 250215A: Fermi GBM Observation
Date
2025-02-16T07:17:46Z (a year ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
L. Scotton (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 02:31:54.94 UT on 15 February 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250215A (trigger 761279519/250215105), which was also
detected by EP-WXT and FXT (Wang et al., GCN 39329),
INTEGRAL SPI-ACS (Barria et al., GCN 39331), AstroSat CZTI (Tembhurnikar et al., GCN 39334),
SVOM/GRM (Zheng et al., GCN 39335) and Swift-XRT (Page et al., GCN 39336).
NOT (Liu et al., GCN 39330, Malesani et al., GCN 39341), SVOM/VT (Xie et al., GCN 39333)
and Gemini-South (Malesani et al., GCN 39339) detected the optical counterpart.
The Fermi GBM on-ground location is consistent with the Swift-XRT position.
The angle from the Fermi LAT boresight is 28 degrees.
The GBM light curve consists of multiple emission episodes with a duration (T90)
of about 13.4 s (50-300 keV). The time-averaged spectrum
from T0-0.8 to T0+14.5 s is best fit by a Band function
with Epeak = 117 +/- 9 keV, alpha = -0.68 +/- 0.09 and beta = -2.38 +/- 0.14.
The event fluence (10-1000 keV) in this time interval is
(6.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+12 s in the 10-1000 keV band is 11.1 +/- 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 39341
Subject
EP250215a / GRB 250215A : NOT optical observations
Date
2025-02-16T03:06:15Z (a year ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
D. B. Malesani (DAWN/NBI and Radboud Univ), D. Xu (NAOC), N. Pyykkinen (NOT and Turku Univ.), M. A. Diaz Teodori (NOT and Turku Univ.) report on behalf of a larger collaboration:
We observed the optical counterpart (Liu et al., GCN 39330; Xie et al., GCN 39333; Malesani et al., GCN 39339) of EP250215a / GRB 250215A (Wang et al., GCN 39329; Fermi GBM Team, GCN 39327; Barria et al., GCN 39331; Tembhurnikar et al., GCN 39334; Zheng et al., GCN 39335) using the ALFOSC instrument installed on the Nordic Optical Telescope (NOT). Observations were carried out in the i band and consisted of 5x300 s exposures, with a mean epoch 2025 Feb 16.076 UT (23.29 hr after the trigger).
The afterglow is well detected with a magnitude i = 21.34 +- 0.07 AB, calibrated against several stars from the Pan-STARRS catalog.
GCN Circular 39340
Subject
GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
Date
2025-02-15T18:49:42Z (a year ago)
From
Brajesh Kumar at SWIFAR, YNU <brajesh@ynu.edu.cn>
Via
Web form
Xiangkun Liu, Yu Pan, Edoardo P. Lagioia, Yaosong Yu, Guowang Du, Brajesh Kumar, Yuan Fang, Jinghua Zhang, Xinlei Chen, Xingzhu Zou, Yuanpei Yang (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu, Jianyan Wei (all NAOC), Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team:
The field of GRB 250215A/EP250215a detected by Fermi Gamma-ray Burst Monitor (GBM) and EP-WXT (Fermi GBM Team, GCN 39327; Wang et al., GCN 39329) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgr band photometric observations were conducted starting from 16:33:12 2025-02-15 UT (~14 hr after the trigger) and 3 frames with 300s exposure times were taken. There is non-detection of the optical candidate (Liu et al., GCN 39330; Xie et al., GCN 39333; Malesani et al., GCN 39339) in the stacked images of uvgr bands. The preliminary photometry and 3 sigma upper limits are listed below.
Start_Time(UT) | Band | Exp(s)| LimMag (AB)
--------------------|--------|-------|------------
2025-02-15T16:33:12 | u | 300*3 | >20.65
2025-02-15T16:50:23 | v | 300*3 | >20.91
2025-02-15T16:33:12 | g | 300*3 | >21.21
2025-02-15T16:50:23 | r | 300*3 | >21.45
-------------------------------------------------------------------------------------------------
Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21.
-------------------------------------------------------------------------------------------------
GCN Circular 39339
Subject
GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
Date
2025-02-15T17:52:20Z (a year ago)
From
mariaedvige.ravasio@ru.nl
Via
Web form
Daniele B. Malesani (DAWN/NBI and Radboud Univ.), Jonathan Quirola-Vasquez (Radboud Univ.), Antonio Martin-Carrillo (UCD), Andrew J. Levan (Radboud Univ. and Warwick Univ.), Maria E. Ravasio (Radboud and INAF), Peter G. Jonker (Radboud Univ.) report on behalf of a larger collaboration:
We observed the optical counterpart (Liu et al., GCN 39330; Xie et al., GCN 39333) of EP250215a / GRB 250215A (Fermi GBM Team, GCN 39327; Wang et al., GCN 39329; Barria et al., GCN 39331; Tembhurnikar et al., GCN 39334; Zheng et al., GCN 39335) using the GMOS instrument installed on the Gemini-South telescope.
While no spectroscopy could be unfortunately performed due to a technical fault with the instrument, in a single 60-s i-band image, taken starting on 2025 Feb 15 at 08:48:23 UT (6.27 hr after the EP/WXT trigger), the afterglow is well detected with a magnitude i = 20.05 +- 0.07 AB (calibrated against nearby stars from the Pan-STARRS catalog).
We note that our (i-band) magnitude is brighter than the z-band measurement reported at an earlier epoch by Liu et al. (GCN 39330). The VT_R magnitude (Xie et al., GCN 39333), taken at an intermediate epoch, is brighter than both other reports. This is likely to indicate a rebrightening.
GCN Circular 39336
Subject
GRB 250215A: Swift-XRT refined Analysis
Date
2025-02-15T11:39:14Z (a year ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Perri (SSDC
& INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), S.
Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU) and P.A. Evans
(U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 1.7 ks of XRT data for the Einstein Probe/WXT-detected
burst GRB 250215A, from 9.5 ks to 16.1 ks after the Einstein Probe/WXT
trigger, also detected by Fermi/GBM (GCN Circ. 39327) and INTEGRAL (GCN
Circ. 39331). The data are entirely in Photon Counting (PC) mode.
We detect a bright, previously uncatalogued X-ray source at the
following coordinates: RA/Dec(J2000) = 156.33119, -27.69834, which is
equivalent to
RA (J2000): 10 25 19.48
Dec(J2000): -27 41 54.0
with an uncertainty of 3.6 arcsec (radius, 90% confidence). This source
is 6 arcsec from the FXT position (GCN Circ. 39329) and 0.35 arcsec
from the NOT optical counterpart (GCN Circ. 39330).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.1 (+/-0.4).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.95 (+0.23, -0.22). The
best-fitting absorption column is 1.2 (+0.7, -0.5) x 10^21 cm^-2,
consistent with the Galactic value of 6.8 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 3.5 x 10^-11 (4.4 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.2 (+0.7, -0.5) x 10^21 cm^-2
Galactic foreground: 6.8 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.95 (+0.23, -0.22)
If the light curve continues to decay with a power-law decay index of
1.1, the count rate at T+24 hours will be 0.038 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x
10^-12 (1.7 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00019554.
This circular is an official product of the Swift-XRT team.
GCN Circular 39335
Subject
GRB 250215A: SVOM/GRM observation
Date
2025-02-15T11:26:40Z (a year ago)
Edited On
2025-02-16T05:29:05Z (a year ago)
From
zhengchao_astro@foxmail.com
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Chao Zheng, Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Yue Huang, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Frédéric Piron (LUPM), Nicolas Dagoneau, Stéphane Schanne (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia (IRAP), Wen-Jin Xie (NAOC)
report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by a long burst GRB 250215A (sb25021501) at 2025-02-15T02:32:03.300 UTC (T0), which was also observed by Fermi/GBM (Fermi GBM team, GCN #39327), AstroSat (M. Tembhurnikar et al., GCN #39334) and INTEGRAL (Patrizia Barria et al., GCN 39331).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of about 29.8 +7.8/-8.0 seconds in the 15-5000 keV band.
The time-averaged spectrum from T0-25 to T0+25 s could be fit by a power law with high energy exponential cutoff function. The power law index is -1.39 +/- 0.15 and the cutoff energy, parameterized as Epeak, is 134 +/- 36 keV. The event fluence (10-1000 keV) in this time interval is (6.02 +/- 0.47)E-06 erg/cm^2.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb250215A.png
In addition, the position of this burst, as determined by EP/WXT (Wang et al., GCN #39329), is located at about 72 degrees from the SVOM optical axis, and outside the ECLAIRs field of view.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.
The SVOM/GRM point of contact for this burst is: Chao Zheng (IHEP) (zhengchao97@ihep.ac.cn)
GCN Circular 39334
Subject
EP250215a / GRB 250215A: AstroSat CZTI detection
Date
2025-02-15T09:57:33Z (a year ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
M. Tembhurnikar (IUCAA), G. Waratkar (IITB), J. Joshi (IUCAA), 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 250215A which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 39294), INTEGRAL/SPI-ACS (Barria et al., GCN Circ. 39331), and is associated with EP250215a (Wang et al., GCN Circ. 39329).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-02-15 02:32:07.5 UTC. The measured peak count rate associated with the burst is 131 (+31, -33) counts/s above the background in the combined data of three quadrants (out of four), with a total of 585 (+253, -261) counts. The local mean background count rate was 247 (+4, -4) counts/s. Using cumulative rates, we measure a T90 of 15 (+9, -7) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-02-15 02:32:07.4 UTC. The measured peak count rate associated with the burst is 388 (+59, -65) counts/s above the background in the combined data of all quadrants, with a total of 1974 (+583, -715) counts. The local mean background count rate was 2231 (+8, -8) counts/s. We measure a T90 of 13 (+9, -5) 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 39333
Subject
GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
Date
2025-02-15T09:53:01Z (a year ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
W.J. Xie (NAOC), Y.H. Cheng (SWIFAR, YNU), B.-T.Wang (YNAO, CAS), L.P. Xin, Y.L. Qiu, H.L. Li, C. Wu, Z.H. Yao, Y.N. Ma, X.H. Han, H.B. Cai, J. Wang, J.Y. Wei (NAOC), report on behalf of the SVOM team:
The SVOM/VT conducted a ToO follow-up observations of the GRB 250215A / EP250215a (Fermi GBM Team, GCN 39327, Wang et al., GCN 39329) in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously.
With the X band downlinked data, an uncatalogued optical source was clearly detected within the errorbox of EP/FXT (Wang et al., GCN 39329) in VT_R and VT_B single images, compared to the PanSTARRS and DESI catalogues. The position of source is consistent with the candidate reported (Liu et al., GCN 39300).
The brightness of the source was estimated to be 19.3+/-0.1 mag in AB magnitude in VT_R, 22.2+/-0.2 mag in AB magnitude in VT_B, at the mid time of 1.07 hours post the burst, with an exposure time of 100 seconds for each frame.
Considering the red color of the source based on the VT data, it is likely a high redshift or highly extincted burst. More deep follow-ups are encouraged.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS.
GCN Circular 39332
Subject
EP250215a: Global MASTER-Net observations report
Date
2025-02-15T09:27:45Z (a year ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin,
V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP250215a ( EP Team et al., GCN 39329) errorbox 12952 sec after notice time and 19891 sec after trigger time at 2025-02-15 08:03:34 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 36 deg. The sun altitude is -26.0 deg.
The galactic latitude b = 25 deg., longitude l = 268 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2779105
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
19952 | 2025-02-15 08:03:34 | MASTER-OAFA | (10h 25m 20.58s , -27d 18m 50.7s) | C | 120 | 19.2 |
20089 | 2025-02-15 08:05:51 | MASTER-OAFA | (10h 25m 27.87s , -27d 19m 50.1s) | C | 120 | 19.1 |
20229 | 2025-02-15 08:08:11 | MASTER-OAFA | (10h 25m 22.22s , -27d 20m 50.0s) | C | 120 | 19.2 |
20366 | 2025-02-15 08:10:29 | MASTER-OAFA | (10h 25m 26.63s , -27d 20m 46.2s) | C | 120 | 19.1 |
20501 | 2025-02-15 08:12:43 | MASTER-OAFA | (10h 25m 24.54s , -27d 18m 50.9s) | C | 120 | 19.1 |
20635 | 2025-02-15 08:14:57 | MASTER-OAFA | (10h 25m 24.64s , -27d 20m 24.4s) | C | 120 | 19.1 |
20756 | 2025-02-15 08:17:14 | MASTER-OAFA | (10h 25m 26.91s , -27d 19m 17.0s) | C | 90 | 18.8 |
20861 | 2025-02-15 08:18:58 | MASTER-OAFA | (10h 25m 20.89s , -27d 19m 50.8s) | C | 90 | 18.8 |
20982 | 2025-02-15 08:20:44 | MASTER-OAFA | (10h 25m 22.37s , -27d 18m 51.4s) | C | 120 | 19.1 |
21119 | 2025-02-15 08:23:01 | MASTER-OAFA | (10h 25m 28.21s , -27d 19m 51.3s) | C | 120 | 19.1 |
21256 | 2025-02-15 08:25:19 | MASTER-OAFA | (10h 25m 21.51s , -27d 20m 51.9s) | C | 120 | 19.0 |
21391 | 2025-02-15 08:27:34 | MASTER-OAFA | (10h 25m 27.37s , -27d 20m 41.7s) | C | 120 | 19.0 |
21526 | 2025-02-15 08:29:48 | MASTER-OAFA | (10h 25m 25.28s , -27d 18m 52.8s) | C | 120 | 19.0 |
21660 | 2025-02-15 08:32:03 | MASTER-OAFA | (10h 25m 25.40s , -27d 20m 40.2s) | C | 120 | 19.0 |
21795 | 2025-02-15 08:34:17 | MASTER-OAFA | (10h 25m 28.35s , -27d 19m 02.2s) | C | 120 | 19.0 |
21932 | 2025-02-15 08:36:35 | MASTER-OAFA | (10h 25m 21.96s , -27d 19m 54.5s) | C | 120 | 19.0 |
22067 | 2025-02-15 08:38:49 | MASTER-OAFA | (10h 25m 22.37s , -27d 18m 55.5s) | C | 120 | 18.9 |
22204 | 2025-02-15 08:41:06 | MASTER-OAFA | (10h 25m 28.60s , -27d 19m 56.0s) | C | 120 | 19.0 |
22337 | 2025-02-15 08:43:20 | MASTER-OAFA | (10h 25m 21.80s , -27d 20m 57.2s) | C | 120 | 18.8 |
22474 | 2025-02-15 08:45:37 | MASTER-OAFA | (10h 25m 28.74s , -27d 20m 57.8s) | C | 120 | 18.9 |
22609 | 2025-02-15 08:47:52 | MASTER-OAFA | (10h 25m 25.92s , -27d 19m 19.8s) | C | 120 | 18.9 |
22748 | 2025-02-15 08:50:11 | MASTER-OAFA | (10h 25m 26.03s , -27d 20m 48.4s) | C | 120 | 18.8 |
22886 | 2025-02-15 08:52:28 | MASTER-OAFA | (10h 25m 28.99s , -27d 19m 28.0s) | C | 120 | 18.7 |
23213 | 2025-02-15 08:57:55 | MASTER-OAFA | (10h 25m 24.10s , -27d 19m 02.5s) | C | 120 | 18.7 |
23486 | 2025-02-15 09:02:28 | MASTER-OAFA | (10h 25m 23.94s , -27d 21m 04.4s) | C | 120 | 18.7 |
23619 | 2025-02-15 09:04:42 | MASTER-OAFA | (10h 25m 29.40s , -27d 21m 00.5s) | C | 120 | 18.7 |
23754 | 2025-02-15 09:06:57 | MASTER-OAFA | (10h 25m 26.53s , -27d 19m 19.4s) | C | 120 | 18.6 |
23889 | 2025-02-15 09:09:12 | MASTER-OAFA | (10h 25m 26.64s , -27d 20m 45.9s) | C | 120 | 18.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 39331
Subject
EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
Date
2025-02-15T07:50:45Z (a year ago)
From
Aishwarya L Thakur at INAF-IAPS, Rome <aishth@outlook.com>
Via
Web form
Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Luigi Piro(a), Lorenzo Natalucci(a,b) report:
GRB 250215A was discovered by Fermi/GBM (GCN 39327) at 2025-02-15T02:31:54 (UTC) and Einstein Probe/WXT (GCN 39329) at 2025-02-15T02:32:03 (UTC).
In an SPI-ACS light curve above 80 keV, we find a signal temporally coincident with the GBM detection, having an approximate duration of ~ 18 sec. The signal consists of three pulses over this duration. Our detection confirms that GRB 250215A and EP250215A are the same event.
The approximate peak count rate in SPI-ACS for E>80 keV is 68,000 cts/s, over a median background rate of 64,458 cts/s.
This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany.
-----
(a) INAF/IAPS-Rome
(b) ICSC National Research Centre for High-Performance Computing
GCN Circular 39330
Subject
EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
Date
2025-02-15T04:44:25Z (a year ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
Web form
X. Liu, Z.P. Zhu, J. An, S.Y. Fu, S.Q. Jiang, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), N. Pyykkinen, M. A. Diaz Teodori (NOT) report on behalf of a large collaboration:
We observed the field of EP250215a (Wang et al., GCN 39329), using the ALFOSC instrument mounted on the Nordic Optical Telescope (NOT).
EP250215a is basically consistent with GRB 250215A also newly detected by Fermi/GBM (Fermi GBM team, GCN 39327) in both trigger time and position. Therefore, they seem to be an identical event.
We obtained 5 x 180 s frames in the SDSS-z band at a median time of 0.45 hr after the EP trigger. An uncatalogued optical transient (OT) is detected in the stacked image within the EP/FXT error circle (Wang et al., GCN 39329) at coordinates
R.A. (J2000) = 10:25:19.49
Dec. (J2000) = -27:41:54.37
with an uncertainty of ~ 0.5 arcsec. The OT has z ~ 20.6 mag, calibrated with Pan-STARRS DR1 and not corrected for Galactic extinction. There was no known NEO object at the above position by checking MPC. The 3-sigma limiting magnitude of the image is z ~ 21.5 (AB).
We thus conclude the OT is very likely the optical counterpart of EP250215a.
Further observations are planned.
GCN Circular 39329
Subject
EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
Date
2025-02-15T04:26:05Z (a year ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
C. Y. Wang(THU), A. Li (BNU), D. H. Zhao, Z. X. Ling (NAOC, CAS) report on behalf of the Einstein Probe team:
We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP250215a (trigger ID: 01709131576). The WXT position of the source is R.A. = 156.3430 deg, DEC = -27.7040 deg (J2000) with an uncertainty of 2.9 arcmin in radius (90% C.L. statistical and systematic). The transient triggered EP-WXT at 2025-02-15T02:32:03 (UTC). The trigger time and the position are generally consistent with the likely long GRB 250215A (GCN #39327).
A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error cirlce, an uncatalogued X-ray source was detected at R.A. = 156.3301 deg, DEC = -27.6997 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic).
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
GCN Circular 39328
Subject
Fermi GRB 250215A: Global MASTER-Net observations report
Date
2025-02-15T03:17:00Z (a year ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin,
V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250215A ( Fermi GBM team, GCN 39327) errorbox 553 sec after notice time and 587 sec after trigger time at 2025-02-15 02:41:42 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 40 deg. The sun altitude is -19.3 deg.
The galactic latitude b = 20 deg., longitude l = 273 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2779054
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
617 | 2025-02-15 02:41:42 | MASTER-SAAO | (10h 29m 47.15s , -34d 28m 22.2s) | C | 60 | 18.3 |
677 | 2025-02-15 02:41:42 | MASTER-SAAO | (10h 29m 47.15s , -34d 28m 22.1s) | C | 180 | 18.7 | Coadd
697 | 2025-02-15 02:43:01 | MASTER-SAAO | (10h 29m 47.06s , -34d 28m 20.0s) | C | 60 | 18.2 |
776 | 2025-02-15 02:44:20 | MASTER-SAAO | (10h 29m 46.95s , -34d 28m 17.6s) | C | 60 | 18.2 |
855 | 2025-02-15 02:45:39 | MASTER-SAAO | (10h 29m 46.86s , -34d 28m 15.1s) | C | 60 | 18.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 39327
Subject
GRB 250215A: Fermi GBM Final Real-time Localization
Date
2025-02-15T02:42:29Z (a year 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 02:31:54 UT on 15 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250215A (trigger 761279519.94116 / 250215105).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 157.6, Dec = -34.5 (J2000 degrees, equivalent to J2000 10h 30m, -34d 30'), with a statistical uncertainty of 2.7 degrees.
The angle from the Fermi LAT boresight is 21.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250215105/quicklook/glg_skymap_all_bn250215105.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250215105/quicklook/glg_healpix_all_bn250215105.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250215105/quicklook/glg_lc_medres34_bn250215105.gif