GRB 200623A
GCN Circular 28047
Subject
GRB 200623A: Swift XRT further observations
Date
2020-06-30T22:08:27Z (5 years ago)
From
Boris Sbarufatti at PSU <bxs60@psu.edu>
B. Sbarufatti (PSU), P.A. Evans (U. Leicester) and K. K. Simpson (PSU) report on behalf of the Swift XRT team.
Swift performed a second observation of the field of GRB 200623A, with a 4.5 ks exposure.
The only uncatalogued source in the field, Source 3 (Tohuvavohu et al., GCN 28023), is still detected and shows no evidence of fading, so we conclude that it is not the GRB afterglow.
This circular is an official product of the Swift XRT team.
GCN Circular 28036
Subject
GRB 200623A: Further MMTCam Observations of XRT Source #3
Date
2020-06-27T23:23:16Z (5 years ago)
From
Wen-fai Fong at Northwestern U <wfong@northwestern.edu>
W. Fong (Northwestern) reports:
"We re-visited the location of XRT source #3 of the short GRB 200623A (Fermi-GBM Collab. et al., GCN 28011; DeLaunay et al., GCN 28013; Tohuvavohu et al., GCN 28023) with the MMT/MMTCam at a mid-time of 2020 June 26.176 UT (3.04 days post-burst and 2.0 days after our initial observations: Rastinejad et al., GCN 28026). We acquired 21x120-sec of r-band imaging in 0.88" seeing, and the 3-sigma depth of our image is 24.4 AB mag.
Upon inspection of the XRT source #3 position (90% confidence), we detect the faint optical source first reported in TNG observations (D'Avanzo et al.; GCN 28021) with r = 24.3 +/- 0.3 mag, at the same flux level as previous detections. In addition to a few catalogued sources, we report on an additional source toward the Eastern edge of the XRT position and in the wings of the bright star, with RA = 16:07:59.64, Dec = +53:28:43.6 (J2000) and r~22.2 AB mag. This source was marginally detected in our previous set of imaging although partially blended with the bright star, and it is not possible to discern at present whether this source is point-like or extended in nature. Finally, we do not detect the extended LBT source at the center of the XRT position (Rossi and D'Avanzo et al., GCN 28034), likely due to lack of sensitivity.
We perform image subtraction relative to our previous epoch, and do not detect any significant residuals. Thus, we find no evidence for significant variability in or around the XRT source #3 position, enabling a limit of r > 23.0 AB mag at 25.03 hrs post-burst on optical afterglow emission associated with this XRT candidate (c.f., Rastinejad et al., GCN 28026).
We thank Nelson Caldwell and Michael Calkins at the MMT for the rapid scheduling and execution of these observations."
GCN Circular 28034
Subject
GRB 200623A: LBT optical observations
Date
2020-06-26T09:30:40Z (5 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A. Rossi (INAF-OAS) and P. D'Avanzo (INAF-OA Brera) report on behalf of
the CIBO collaboration:
We observed the field of GRB200623A (DeLaunay et al., GCN 28013)
simultaneously in the r' and z' bands with the LBC imager mounted on LBT
(Mt Graham, AZ, USA). Observations started at 05:58 UT on 2020-06-25,
50.7 hr after the GRB trigger and finished at 06:24 UT and allowed us to
obtain 20min of exposure in each band. Observations were performed under
good seeing conditions (seeing ~0.9") and reached a depth of r~26 mag.
The images covered all the three sources found by XRT (Sbarufatti et
al., GCN 28023). No new point source is detected within their error circles.
Image subtraction against TNG r-band images obtained on 2020-06-23
(D'Avanzo et al., GCN 28021) using HOTPANTS (v5.1.11) does not reveal
any flux variation in the candidate found within the error circle of the
XRT source #3. The near-by galaxy at z~0.33 noticed by D'Avanzo et al.
(GCN 28021) is too close to saturation in LBC images, preventing us to
make any statement about possible flux variations within the galaxy.
We also note that a faint, extended source is present within the XRT
error circle of source #3, visible in both the r' and z' images, and not
mentioned in previous reports about this event. This is also a candidate
host galaxy of XRT source #3 though with a higher chance association
probability compared to the brighter galaxy. Further Swift/XRT
observations will help establishing variability and possibly reducing
the X-ray position uncertainty.
We acknowledge the excellent support from the LBTO and LBT-INAF staff,
particularly B. Rothberg, F. Cusano, S. Paiano and D. Paris, in
obtaining these observations.
GCN Circular 28033
Subject
GRB 200623A : SMA observations at Swift/XRT Source #3
Date
2020-06-26T07:19:35Z (5 years ago)
From
Yuji Urata at Nat. Central U. <urata@astro.ncu.edu.tw>
Kuiyun Huang (CYCU), Yuji Urata (NCU), Glen Petitpas (CfA)
report
We used SMA to observe the location of the Swift/XRT source #3
(Evans, GCN Circ. 28015) as one of the afterglow candidates of
GRB200623A (Fermi/GBM Team, GCN Circ. 28011; DeLaunay et al., GCN
Circ. 28013, 28016). The 230 GHz observation was started at ~1 days
after the burst. No clear submm source at the Swift/XRT sources #3
position was found brighter than ~1 mJy.
We thank the staff of SMA.
GCN Circular 28026
Subject
GRB 200623A: MMT observations at XRT Source #3
Date
2020-06-24T21:47:34Z (5 years ago)
From
Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024@u.northwestern.edu>