| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB250612519 |
|
| T0 |
12:27:55.934 UTC |
Fermi_GBM |
| ra |
229.6528° |
GCN_circulars,Optical |
| decl |
-26.7677° |
GCN_circulars,Optical |
| T90 |
10.752 s |
Fermi_GBM |
| T90_error |
0.923 s |
Fermi_GBM |
| T90_start |
12:27:55.934 UTC |
Fermi_GBM |
| fluence |
5.53e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
2.75e-08 erg/cm² |
Fermi_GBM |
| T100 |
10.752 s |
|
| GBM_located |
False |
|
| mjd |
60838.51939738426 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB250612519 |
| trigger_name |
bn250612519 |
| ra |
229.6542° |
| decl |
-26.7569° |
| pos_error |
3.07e+00° |
| datum |
2025-06-12 |
| t_trigger |
12:27:56.190 UTC |
| T90 |
10.752 s |
| T90_error |
0.923 s |
| T90_start |
12:27:55.934 UTC |
| fluence |
5.53e-06 erg/cm² |
| fluence_error |
2.75e-08 erg/cm² |
| flux_1024 |
1.21e+01 erg/cm²/s |
| flux_1024_error |
3.45e-01 erg/cm²/s |
| flux_1024_time |
2.88e+00 erg/cm²/s |
| flux_64 |
1.56e+01 erg/cm²/s |
| flux_64_error |
1.65e+00 erg/cm²/s |
| GCN 40701 table |
|---|
| GRB_name |
GRB250612B |
| GCN_number |
40701 |
| Detection_method |
Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 40701
SUBJECT: GRB 250612B: BALROG localization (Fermi Trigger 771424081 / GRB 250612519)
DATE: 25/06/12 13:17:08 GMT
FROM: Jochen Greiner at MPE
T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
771424081 at 12:27:56 on 12 June 2025 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
RA(2000.0) = 226.1 deg
Decl.(2000.0) = -28.9 deg
The 1 sigma statistical error radius is 2.4 deg.
We estimate an additional systematic error of 1 deg.
This is consistent in time and position with the Einstein Probe detection of the X-ray transient EP 250612a (GCN 40700).
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB250612519/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB250612519/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB250612519/json
|
| GCN 40702 table |
|---|
| GRB_name |
GRB250612B |
| GCN_number |
40702 |
| Detection_method |
Fermi GBM Other |
| ra |
231.2800° |
| decl |
-29.0500° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 40702
SUBJECT: GRB 250612B (250612519/771424081): Fermi GBM Final Localization
DATE: 25/06/12 14:23:44 GMT
FROM: eliza.neights@gmail.com
The Fermi GBM team reports the detection of a likely LONG GRB
"At 12:27:56.19 UT on 12 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250612B (trigger 771424081/250612519).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 231.28, Dec = -29.05 (J2000 degrees, equivalent to J2000 15h 25m, -29d 03'),
with a statistical uncertainty of 2.0 degrees.
The angle from the Fermi LAT boresight is 71.04 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250612519/quicklook/glg_skymap_all_bn250612519.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/bn250612519/quicklook/glg_healpix_all_bn250612519.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250612519/quicklook/glg_lc_medres34_bn250612519.gif" |
| GCN 40710 table |
|---|
| GRB_name |
GRB250612B |
| GCN_number |
40710 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 40710
SUBJECT: EP250612a/GRB 250612B: JinShan optical upper limit
DATE: 25/06/12 17:24:35 GMT
FROM: liuxing@nao.cas.cn
X. Liu, Z.P. Zhu, J. An, S.Q. Jiang, D. Xu (NAOC), S.Y. Fu(HUST), J.Z. Liu (XAO) report on behalf of a large collaboration:
We observed the field of EP250612a detected by EP/WXT (Hua et al., GCN 40700), which is very likely GRB 250612B by Fermi/GBM (Preis & Greiner, GCN 40701; Fermi GBM tea, GCN 40702), using the 100cm-C telescope (100C) of the JinShan project, located at Altay, Xinjiang, China. Observations started at 15:45:13 UT on 2025-06-12, i.e., 3.29 hr after the EP trigger, and 18 x 200 s frames were obtained in the Sloan i-band.
No new optical source is detected within the EP/FXT error circle (Hua et al., GCN 40700), down to a 3-sigma upper limit of i ~ 20.2 mag (AB), calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction.
We acknowledge the excellent support from T.Q. Chen for enabling these observations. |
| GCN 40717 table |
|---|
| GRB_name |
GRB250612B |
| GCN_number |
40717 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
12:27:56.190 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 40717
SUBJECT: GRB 250612B: Fermi GBM Observation
DATE: 25/06/13 06:34:50 GMT
FROM: Rushikesh Sonawane at IISER, TVM
R. Sonawane (IISER, TVM) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 12:27:56.19 UT on 12 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250612B (trigger 771424081/250612519).
which was also detected by EP-WXT (Hua et al. 2025, GCN 40700).
The Fermi GBM on-ground location is consistent with the EP-WXT position.
The angle from the Fermi LAT boresight is 68 degrees.
The GBM light curve consists of single emission episode with a duration (T90)
of about 10.8 s (50-300 keV). The time-averaged spectrum
from T0-4.4 to T0+18.2 s is best fit by
a Band function with Epeak = 47.80 +/- 1.53 keV,
alpha = -0.92 +/- 0.09, and beta = -3.47 +/- 0.39.
A Comp model fits the spectrum equally well, with a power-law index = –0.98 +/- 0.07
and cutoff energy parameterized as Epeak = 49.14 +/- 1.26 keV.
The event fluence (10-1000 keV) in this time interval is
(5.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.9 s in the 10-1000 keV band is 12.1 +/- 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 40727 table |
|---|
| GRB_name |
GRB250612B |
| GCN_number |
40727 |
| Detection_method |
Optical |
| ra |
229.6528° |
| decl |
-26.7677° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 40727
SUBJECT: EP250612a / GRB 250612B: NOT optical observations of the afterglow candidate
DATE: 25/06/14 08:29:34 GMT
FROM: Antonio Martin-Carrillo at UCD,Space Science Group
A. de Ugarte Postigo (LAM), A. Martin-Carrillo (UCD), G. Corcoran (UCD), D. B. Malesani (DAWN/NBI and Radboud), D. Xu (NAOC), L. Cotter (UCD), B. P. Gompertz (U. Birmingham), A. A. Djupvik (NOT), L. Fuglsang (NOT), report on behalf of a larger collaboration.
We observed the field of EP250612a / GRB 250612B detected by EP (Hua et al., GCN 40700) and Fermi (Fermi GBM team, GCN 40702), using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 12x100 s exposures in the SDSS r-band, starting at 23:19 UT on 2025-05-13 (1.952 days after the EP trigger).
At J2000 coordinates RA:15:18:36.667, DEC: -26:46:03.624 (error 0.5â€), consistent with those by Li et al. (GCN 40716), the optical counterpart is detected in our stacked image with a preliminary magnitude:
r = 23.59 +/- 0.22 (AB).
The photometric calibration was performed using nearby stars from the Pan-STARRS catalog and the magnitudes are not corrected for Galactic extinction. |