Gamma-ray Burst 141215A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN Circular #17186
K. Hurley, on behalf of the IPN,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, and
D. M. Smith, J. McTiernan, R. Schwartz, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report:
A long-duration, bright GRB 141215A has been observed by Fermi (GBM trigger 440342778), Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), RHESSI, and Swift (BAT), so far, at about 48376 s UT (13:26:16). The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     179.056 (11h 56m 13s) -52.745 (-52d 44' 44")
    Corners:
     179.620 (11h 58m 29s) -52.523 (-52d 31' 22")
     178.533 (11h 54m 08s) -53.178 (-53d 10' 40")
     178.486 (11h 53m 57s) -52.965 (-52d 57' 53")
     179.570 (11h 58m 17s) -52.309 (-52d 18' 31")
    ---------------------------------------------
```
The error box area is 575 sq. arcmin, and its maximum dimension is 1.1 deg (the minimum one is 10 arcmin). The Sun distance was 68 deg.
This box may be improved.
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB141215_T48373/IPN/
The time history and spectrum will be given in forthcoming GCN Circulars.
GCN Circular #17187
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lyssenko, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration, intense GRB 141215A (IPN triangulation: Hurley et al., GCN 17186) triggered Konus-Wind at T0=48373.645 s UT (13:26:13.645).
The light curve shows a multi-peaked structure with a total duration of ~15 s. The emission is seen up to ~10 MeV.
As observed by Konus-Wind, the burst had a fluence of 2.8(-0.3,+0.3)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+10.560 s, of 7.7(-0.8,+0.8)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+13.824 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.29 (-0.14,+0.14), the high energy photon index beta = -2.80 (-0.69,+0.25), the peak energy Ep = 241 (-17,+28) keV, chi2 = 102/97 dof.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB141215_T48373/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #17188
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 IPN GRB 141215A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00035
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 IPN 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; and 2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #17189
P. Jenke (UAH), A. von Kienlin (MPE) and E. Burns (UAH) report on behalf of the Fermi GBM Team:
"At 13:26:15.75 on December 15 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141215A (trigger 440342778/141215560). GBM's location is consistent with the IPN Triangulation (K. Hurley et al. 2014, GCN 17186).
The angle of the burst direction to the Fermi LAT boresight is 130 degrees.
The GBM light curve consists of three peaks with a duration (T90) of about 11 s (50-300 keV). The time-averaged spectrum from T0+0.0 s to T0+14.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.62 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 392 +/- 11 keV. The spectrum is equally well fit by the BAND function with Beta = -3.5 +/- 0.5. The event fluence (10-1000 keV) in this time interval is (2.94 +/- 0.04)E-05 erg/cm^2. The 1 sec peak photon flux measured starting from T0+10.8 s in the 10-1000 keV band is 20.6 +/- 0.7 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #17190
V. D'Elia (ASDC) & L. Izzo (URoma/ICRA) report on behalf of the Swift-XRT team
Swift-XRT has observed the error box of the IPN GRB 141215A (Hurley et al. GCN 17186) in a series of observations tiled on the sky. The total exposure time is 8.0 ks spread over 2 fields. The observations started ~100 ks after the IPN trigger and cover ~80% of the error box. We detect three sources with S/N>2.5 within the IPN error box, namely (ordered by descending RA):
Source 1
```
RA:  178.98953 = 11h 55m 57.49s (J2000) 
Dec: -52.90081 = -52d 54' 02.9" (J2000)
Err: 3.6 arcsec (radius, 90% confidence)
Exposure time: 3.3 ks.
```
Source 2
```
RA:  178.95882 = 11h 55m 50.12s (J2000) 
Dec: -52.82640 = -52d 49' 35.1" (J2000)
Err: 4.3 arcsec (radius, 90% confidence)
Exposure time: 3.4 ks.
```
Source 3
```
RA:  178.80790 = 11h 55m 13.90s (J2000) 
Dec: -52.84520 = -52d 50' 42.7" (J2000)
Err: 5.1 arcsec (radius, 90% confidence)
Exposure time: 3.4 ks.
```
Source #1 has a 2MASS counterpart and it is fairly bright (5E-2 cts/s) for being an X-ray afterglow at more than 30 hours from the trigger. Thus, the current candidates are #2 and #3. We cannot assess variability at this time, so a secure identification of the afterglow is not possible. We caution that the XRT observations cover just 80% of the IPN error box. A further Swift-XRT follow-up is planned.
Details on the present analysis can be found at:
http://www.swift.ac.uk/xrt_products/TILED_GRB00035/
This is an official product of the Swift-XRT team.
GCN Circular #17217
FROM: Valerio D'Elia at ASDC
V. D'Elia (ASDC), L. Izzo (URoma/ICRA) & M. M. Chester (PSU) report on behalf of the Swift team
Swift-XRT observed again the field of the IPN GRB 141215A (Hurley et al. GCN 17186). The observation started on 2014-12-21 at 01:22UT, i.e., ~5.5 days after the burst detection. Source #1 (that with a 2MASS counterpart) and source #3 (which has a DSS counterpart) reported by D'Elia & Izzo (GCN 17190) are still detected with a count rate comparable to that of the first exposure and are thus not related with the GRB. On the other hand, source #2 faded considerably with respect to the first observation. Its decay index is alpha~1, which is consistent with a typical afterglow behavior. We thus conclude that source #2 is the X-ray counterpart of GRB 141215A.
Swift/UVOT observed the initial two tiled fields for GRB 141215A beginning ~100 ks after the IPN trigger. No optical counterpart was detected for Swift/XRT Source #2 (D'Elia et al. GCN Circ. 17190). Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are:
```
Source #2:
Filter       T_start(s)      T_stop(s)     Exp(s)    UL
white         118715          125192       1026    > 21.35
v             119529          120370        824    > 19.39
u             117902          124472       1580    > 20.85
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.176 in the direction of the burst (Schlegel et al. 1998).
Details on the XRT analysis can be found at:
http://www.swift.ac.uk/xrt_products/TILED_GRB00035/
This is an official product of the Swift team.

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Jochen Greiner, last update: 24-Jan-2015 [Disclaimer]