Gamma-ray Burst 251014D

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Oct 25 21:57:22 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1404126,   Seg_Num: 0
POINT_RA:        323.912d {+21h 35m 39s} (J2000)
POINT_DEC:       -41.846d {-41d 50' 46"} (J2000)
IMG_START_DATE:  20962 TJD;   287 DOY;   25/10/14
IMG_START_TIME:  79036.21 SOD {21:57:16.21} UT,   77326.0 [sec] since BAT Trigger Time
COUNTS:          18    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Oct 25 22:00:09 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1404126,   Seg_Num: 0
POINT_RA:        323.913d {+21h 35m 39s} (J2000)
POINT_DEC:       -41.846d {-41d 50' 46"} (J2000)
POINT_ROLL:      239.899d
IMG_START_DATE:  20962 TJD;   287 DOY;   25/10/14
IMG_START_TIME:  79040.58 SOD {21:57:20.58} UT,   77330.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.022
N_STARS:         102
X_OFFSET:        454 [pixels]
Y_OFFSET:        607 [pixels]
X_MAX:           1413 [pixels]
Y_MAX:           1566 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01404126000msufc77330.fits
SUN_POSTN:       200.16d {+13h 20m 38s}   -8.50d {-08d 29' 45"}
SUN_DIST:        108.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      129.59d {+08h 38m 21s}  +22.15d {+22d 09' 13"}
MOON_DIST:       156.85 [deg]
MOON_ILLUM:      38 [%]
GAL_COORDS:      359.51,-47.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      312.03,-25.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Oct 25 22:00:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1404126,   Seg_Num: 0
POINT_RA:        323.913d {+21h 35m 39s} (J2000)
POINT_DEC:       -41.846d {-41d 50' 46"} (J2000)
POINT_ROLL:      239.899d
IMG_START_DATE:  20962 TJD;   287 DOY;   25/10/14
IMG_START_TIME:  79040.58 SOD {21:57:20.58} UT,   77330.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.022
N_STARS:         102
X_OFFSET:        454 [pixels]
Y_OFFSET:        607 [pixels]
X_MAX:           1413 [pixels]
Y_MAX:           1566 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01404126000msufc77330.fits
SUN_POSTN:       200.16d {+13h 20m 38s}   -8.50d {-08d 29' 45"}
SUN_DIST:        108.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      129.59d {+08h 38m 22s}  +22.15d {+22d 09' 11"}
MOON_DIST:       156.85 [deg]
MOON_ILLUM:      38 [%]
GAL_COORDS:      359.51,-47.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      312.03,-25.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Oct 25 22:02:02 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1404126,   Seg_Num: 0
POINT_RA:        323.914d {+21h 35m 39s} (J2000)
POINT_DEC:       -41.847d {-41d 50' 47"} (J2000)
POINT_ROLL:      239.898d
IMG_START_DATE:  20962 TJD;   287 DOY;   25/10/14
IMG_START_TIME:  79198.81 SOD {21:59:58.81} UT,   77488.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.014
N_STARS:         39
X_OFFSET:        214 [pixels]
Y_OFFSET:        367 [pixels]
X_MAX:           1653 [pixels]
Y_MAX:           1806 [pixels]
DET_THRESH:      2
PHOTO_THRESH:    2
SL_URL:          sw01404126000msufc77488.fits
SUN_POSTN:       200.16d {+13h 20m 39s}   -8.50d {-08d 29' 47"}
SUN_DIST:        108.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      129.61d {+08h 38m 25s}  +22.15d {+22d 08' 53"}
MOON_DIST:       156.85 [deg]
MOON_ILLUM:      38 [%]
GAL_COORDS:      359.51,-47.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      312.03,-25.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Oct 25 22:02:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1404126,   Seg_Num: 0
POINT_RA:        323.914d {+21h 35m 39s} (J2000)
POINT_DEC:       -41.847d {-41d 50' 47"} (J2000)
POINT_ROLL:      239.898d
IMG_START_DATE:  20962 TJD;   287 DOY;   25/10/14
IMG_START_TIME:  79198.81 SOD {21:59:58.81} UT,   77488.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.014
N_STARS:         39
X_OFFSET:        214 [pixels]
Y_OFFSET:        367 [pixels]
X_MAX:           1653 [pixels]
Y_MAX:           1806 [pixels]
DET_THRESH:      2
PHOTO_THRESH:    2
SL_URL:          sw01404126000msufc77488.fits
SUN_POSTN:       200.16d {+13h 20m 39s}   -8.50d {-08d 29' 47"}
SUN_DIST:        108.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      129.61d {+08h 38m 26s}  +22.15d {+22d 08' 51"}
MOON_DIST:       156.85 [deg]
MOON_ILLUM:      38 [%]
GAL_COORDS:      359.51,-47.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      312.03,-25.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN Circular #42274
N. J. Klingler (GSFC/UMBC/CRESSTII), S. Dichiara (PSU), R. Gupta (NASA GSFC), N. P. M. Kuin (UCL-MSSL), A. Mei (INAF-OAB), C. Salvaggio (INAF-OAB) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team:
At 21:54:40.55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 251014D (trigger=1404126). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 323.918, -41.839 which is
```
   RA(J2000) = 21h 35m 40s
   Dec(J2000) = -41d 50' 20"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is not available because of a telemetry gap; however, the rate significance of 8.71 indicates that the event is likely real.
The XRT began observing the field at 21:57:16.2 UT, 155.7 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart.
The UVOT source list for the first white image shows no detection of a new source. Typical upper limits are 17th magnitude. Further details will become available when the full data are downloaded.
Burst Advocate for this burst is N. J. Klingler (noelklin AT umbc.edu). 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 #42284
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), S. Campana (INAF-OAB), A. Melandri (INAF-OAR), T. Sbarrato (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:
Swift-XRT has performed follow-up observations of GRB 251014D. We searched for X-ray sources in 2.9 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 5.0 ks, obtained between T0+159.4 s and T0+22.3 ks.
An uncatalogued X-ray source is detected within the estimated 3-sigma Swift-BAT error region (296 arcsec) and is fading with >3-sigma significance, and is therefore likely the GRB afterglow. Using 1351 s of PC mode data and 3 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 323.92080, -41.85533 which is equivalent to:
```
RA (J2000): 21h 35m 40.99s
Dec(J2000): -41d 51' 19.2"
```
with an uncertainty of 3.4 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.71 (+0.12, -0.11).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.64 (+/-0.06). The best-fitting absorption column is 9.7 (+1.9, -1.8) x 10^20 cm^-2, in excess of the Galactic value of 2.1 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 4.1 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
```
Total column:	     9.7 (+1.9, -1.8) x 10^20 cm^-2
Galactic foreground: 2.1 x 10^20 cm^-2
Excess significance: 6.8 sigma
Photon index:	     1.64 (+/-0.06)
```
The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01404126. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/01404126.
This circular is an official product of the Swift-XRT team.
GCN Circular #42285
S. Guziy, I. Perez-Garcia, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki), M. Jelinek (ASU-CAS), A. Kumar (ARIES) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:
Following the detection of GRB 251014D by Swift/BAT (Klingler et al., GCNC 42272), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) responded to this event starting on Oct 14, 23:03 UT (~ 1.1 h after trigger) with 120s clear-filter images. No new source is detected within the Swift/XRT X-ray afterglow error box (Page et al., GCNC 42284) up to magnitude 18.3 using Gaia DR3 Gmag magnitude as reference. Further images were gathered, resulting on an upper limit of 21.0 (a coadd of 1200s on the aggregate, 1.6 post burst, at 23:30 UT).
We thank the staff at Boyden Observatory for their excellent support.
GCN Circular #42286
A.A. Breeveld (UCL-MSSL) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 251014D 160 s after the BAT trigger (Klingler et al., GCN Circ. 42274). No optical afterglow consistent with the XRT position (Page et al., GCN Circ. 42284)is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           160          310          147         >20.7
white              160         4287          344         >20.9
v                 4498         4697          197         >19.2
b                 3882         5439          317         >19.9
u                  318         5312          204         >19.8
w1                4907         5107          197         >19.7
m2                4702         4902          197         >19.6
w2                4293         4493          197         >19.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.020 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #42315
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), R. Gupta (GSFC), N. J. Klingler (GSFC/UMBC/CRESSTII) H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 251014D (trigger #1404126) (Klingler, et al., GCN Circ. 42274). The BAT ground-calculated position is RA, Dec = 323.933, -41.873 deg which is
```
   RA(J2000)  =  21h 35m 43.9s 
   Dec(J2000) = -41d 52' 23.0" 
```
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%.
The mask-weighted BAT light curve shows a main emission followed by weaker emission. T90 (15-350 keV) is 286.98 +- 70.09 sec (estimated error including systematics).
The time-averaged spectrum from T+0.39 to T+310.10 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.38. The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+5.18 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1404126

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Jochen Greiner, last update: 17-Oct-2025 [Disclaimer]