GRB 241207C

GRB 241207C: MAXI/GSC detection

M. Nakajima (Nihon U.), M. Serino (AGU), W. Iwakiri (Chiba U.),
H. Negoro, Y. Kudo, H. Shibui, K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo, S. Sasao, A. Yoshida (AGU),
Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.),
M. Shidatsu, Y. Niida (Ehime U.),
I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA),
Y. Ueda, Y. Okada, K. Fujiwara (Kyoto U.),
M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.),
K. Yamaoka (Nagoya U.),
M. Sugizaki (Kanazawa U.),

report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 22:20:07 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (306.821 deg, -23.399 deg) = (20 27 17, -23 23 56) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.41 deg and 0.34 deg, respectively.
The roll angle of long axis from the north direction is 132.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 91 +- 22 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 20:47 UT 
and in the next transit at 23:53 UT with an upper limit of 20 mCrab for each.

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 241207C. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00129

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.

C.Francile,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
V.Lipunov, I.Panchenko, A.Kuznetsov, K.Zhirkov, E.Gorbovskoy, N.Tiurina,D.Vlasenko, A.Chasovnikov, V.Topolev,
P.Balanutsa, G.Antipov, A.Sankovich,M.Gulyaev, Ya.Kechin, V.Senik  (Lomonosov MSU),
A.Sosnovskij (CrAO RAS),
O.Gress, N.Budnev(ISU),
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
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 MAXI GRB241207C error-box (trigger No 2412072220, GCN #38462
Loading...
 
 , notice time 2024-12-08T00:13:03UT ) 8462 sec after trigger time at 2024-12-08 00:41:09 UT,with upper limit up to  18.6 mag. Observations started at twilight.

 The observations began at zenith distance = 61 deg. The sun  altitude  is -13.9 deg. Distance to Moon is 34deg., distance to Sun is 47deg.
The galactic latitude b = -31 deg., longitude l = 21 deg.


Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2700028

We obtain the following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|_________________________________|_____|_______|_______|_

    8475 | 2024-12-08 00:41:09 |         MASTER-OAFA | (20h 36m 54.99s -22d 53m 32.3s) |   C |    25 | 16.6 |
    8500 | 2024-12-08 00:41:09 |         MASTER-OAFA | (20h 36m 54.99s -22d 53m 32.3s) |   C |    75 | 17.3 |  Coadd
    8486 | 2024-12-08 00:41:09 |         MASTER-OAFA | (20h 27m 07.85s -23d 14m 22.0s) |   C |    45 | 17.9 |
    8531 | 2024-12-08 00:41:09 |         MASTER-OAFA | (20h 27m 07.85s -23d 14m 22.0s) |   C |   345 | 19.0 |  Coadd
    8537 | 2024-12-08 00:42:11 |         MASTER-OAFA | (20h 37m 00.75s -22d 54m 33.0s) |   C |    25 | 16.6 |
    8547 | 2024-12-08 00:42:11 |         MASTER-OAFA | (20h 27m 13.60s -23d 15m 22.0s) |   C |    45 | 18.1 |
    8601 | 2024-12-08 00:43:14 |         MASTER-OAFA | (20h 36m 55.72s -22d 55m 33.7s) |   C |    25 | 16.8 |
    8611 | 2024-12-08 00:43:15 |         MASTER-OAFA | (20h 27m 08.52s -23d 16m 21.9s) |   C |    45 | 18.1 |
    8661 | 2024-12-08 00:44:15 |         MASTER-OAFA | (20h 37m 01.73s -22d 55m 30.7s) |   C |    25 | 16.8 |
    8672 | 2024-12-08 00:44:15 |         MASTER-OAFA | (20h 27m 14.60s -23d 16m 18.7s) |   C |    45 | 18.0 |
    8724 | 2024-12-08 00:45:18 |         MASTER-OAFA | (20h 36m 58.39s -22d 53m 48.8s) |   C |    25 | 16.9 |
    8734 | 2024-12-08 00:45:18 |         MASTER-OAFA | (20h 27m 11.43s -23d 14m 36.5s) |   C |    45 | 18.2 |
    8822 | 2024-12-08 00:46:18 |         MASTER-OAFA | (20h 36m 58.46s -22d 55m 16.4s) |   C |   100 | 17.7 |
    8792 | 2024-12-08 00:46:19 |         MASTER-OAFA | (20h 27m 11.44s -23d 16m 03.0s) |   C |    40 | 18.2 |
    8838 | 2024-12-08 00:47:05 |         MASTER-OAFA | (20h 27m 11.45s -23d 16m 03.3s) |   C |    40 | 18.2 |
    8884 | 2024-12-08 00:47:50 |         MASTER-OAFA | (20h 27m 11.44s -23d 16m 03.5s) |   C |    40 | 18.2 |
    8943 | 2024-12-08 00:48:49 |         MASTER-OAFA | (20h 37m 01.58s -22d 54m 05.1s) |   C |    40 | 17.4 |
    8953 | 2024-12-08 00:48:50 |         MASTER-OAFA | (20h 27m 14.72s -23d 14m 51.6s) |   C |    60 | 18.5 |
    9020 | 2024-12-08 00:50:07 |         MASTER-OAFA | (20h 36m 55.16s -22d 54m 38.4s) |   C |    40 | 17.3 |
    9031 | 2024-12-08 00:50:07 |         MASTER-OAFA | (20h 27m 08.24s -23d 15m 24.4s) |   C |    60 | 18.4 |

Filter C is a clear (unfiltred) band.

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