GRB 200514A

Y. Okamoto (Chuo U.), M. Nakajima, K. Kobayashi, H. Negoro,  
M. Aoki,  R. Takagi, K, Asakura, K, Seino, S. Mokumoto (Nihon U.), 
T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida (AGU), 
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, S. Kitakoga (Chuo U.), 
M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), 
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), 
Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), 
H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), 
T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source
at 02:21:15 UT on 2020 May 14.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (170.101 deg, 19.633 deg) = (11 20 24, +19 37 58) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.26 deg and 0.21 deg, respectively. 
The roll angle of the long axis from the north direction is 46.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 209 +- 38 mCrab
(4.0-10.0keV, 1 sigma error).

Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (169.291, 18.660) deg = (11 17 09, +18 39 36) (J2000)
(R.A., Dec) = (169.683, 18.463) deg = (11 18 43, +18 27 46) (J2000)
(R.A., Dec) = (170.979, 20.746) deg = (11 23 54, +20 44 45) (J2000)
(R.A., Dec) = (170.584, 20.945) deg = (11 22 20, +20 56 42) (J2000)
There was no significant excess flux in the previous transit at UT 00:45 UT
and in the next transit at 03:54 UT with an upper limit of 20 mCrab for each.

Swift/XRT followup observations are requested.

S. Ricciarini (U of Florence),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The MAXI GRB 200514A (Okamoto et al., GCN Circ. 27735
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 ) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 02:21:11.346 UTC on 14 May 2020 (trigger
#1273457651). The burst signal was seen by all CGBM detectors.

The burst light curve shows a weak pulse which starts at T+1.6 sec and
ends at T+7.5 sec. The T90 and T50 durations measured by the SGM data are
5.1 +- 1.1 sec and 2.5 +- 1.1 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1273457651/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.

N. Nakamura, R. Hosokawa, R. Adachi, K. L. Murata, M. Niwano, F.
Ogawa, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the
MITSuME collaboration:

We performed tiling observation for the MAXI/GSC error region of GRB
200514A (Y. Okamoto et al., GCN Circular #27735
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 ; Ricciarini et al.,
GCN Circular #27743
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 ) with an optical tri-color (g', Rc, and Ic) camera
attached to the MITSuME 50cm telescopes at Akeno Observatory in Japan.

The follow up observation started at 2020-05-14 10:36:15 UT, 495
minutes after the trigger.

Our tiling observation covered almost ~65% of the MAXI/GSC error
region (GCN Circular #27735
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 ). Compared our co-added images with the
GSC2.3 and UCAC4 catalogs, we found no bright optical transient in the
observed region except a high proper motion star (R.A.=11:20:26.73,
Dec.=+19:53:14) listed in the NEOWISE/AllWISE high proper motion
objects (Schneider et al. 2016). Because the elevation of the target
field had dropped from 75 deg to 16 deg during the observations and
the sky condition was unstable, the obtained upper limits are
different for each field. The 5-sigma upper limits of the co-added
images are listed below.

Field num. | center position(R.A., Dec.) | size of field(R.A.(arcmin)
x Dec.(arcmin)) | 5-sigma upper limit | MID-UT(UT) | exposure
time(sec)
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Field 0 | 11:21:03, +19:43:24 | 24.9 x 25.9 | g' > 18.4, Rc > 18.2, Ic
> 16.5 | 12:24:50 14 May | 870
Field 1 | 11:19:53, +19:52:19 | 25.6 x 26.1 | g' > 18.0, Rc > 17.7, Ic
> 16.9 | 12:35:31 14 May | 480
Field 2 | 11:20:25, +19:26:36 | 25.8 x 25.9 | g' > 16.8, Rc > 16.7, Ic
> 16.1 | 12:44:04 14 May | 1170
Field 3 | 11:19:15, +19:35:00 | 25.7 x 26.0 | g' > 18.3, Rc > 17.9, Ic
> 17.1 | 12:05:44 14 May | 660
Field 4 | 11:21:41, +19:59:30 | 25.6 x 26.1 | g' > 17.8, Rc > 17.6, Ic
> 16.7 | 11:18:32 14 May | 360
Field 5 | 11:20:30, +20:08:15 | 25.6 x 25.9 | g' > 18.0, Rc > 17.4, Ic
> 16.8 | 12:33:09 14 May | 570
Field 6 | 11:19:49, +19:09:39 | 25.7 x 25.9 | g' > 18.7, Rc > 18.3, Ic
> 17.5 | 12:11:34 14 May | 660
Field 7 | 11:18:42, +19:18:54 | 25.7 x 26.1 | g' > 18.0, Rc > 17.6, Ic
> 16.8 | 11:26:50 14 May | 210
Field 8 | 11:21:55, +20:24:47 | 25.9 x 26.0 | g' > 17.1, Rc > 17.0, Ic
> 15.9 | 16:21:30 14 May | 150
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We used the UCAC4 catalog for the flux calibration. The magnitudes are
expressed in the AB system. The images were processed in real-time
through the MITSuME GPU reduction pipeline (Niwano et al., in prep;
https://github.com/MNiwano/Eclair).

S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

The AstroSat CZT Imager recorded a transient event in all four of its Veto detectors, coincident with the GRB200514A reported by MAXI (Okamoto Y. et al., GCN #27735
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 ) and CALET (Ricciarini S. et al., GCN # 27743).  There was no significant detection in the main CZT detectors.  The sky location reported by MAXI was 155 deg away from the CZTI pointing axis, causing the Veto detectors to face the source. The peak of the light curve occurred at 2020-05-14 02:21:14.435 UT. We estimate a T90 of 9.64 sec from the combined Veto lightcurves.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.