GRB 190404C
GCN Circular 24051
Subject
GRB190404C: GROWTH-India discovery of optical counterpart
Date
2019-04-04T20:27:13Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
Gaurav Waratkar(IITB), Harsh Kumar (IITB), Viraj Karambelkar (IITB), Tsewang Stanzin (IAO, IIA), Varun Bhalerao (IITB), G.C. Anupama (IIA) report on behalf of the GROWTH-India collaboration:
We observed the uncertainty region of GRB190404C (Yamada et al, GCN 24049) at UT 18:08:20 UT corresponding to 4.9 hrs after the alert and obtained an r band image of 600 seconds. We find a new uncatalogued source within the MAXI 90% confidence region:
T - T0 | RA (J2000) | Dec (J2000) | Filt. | Magnitude |
4.9 hrs 14:44:00.896 -22:40:33.02 r 19.62 +/- 0.13
The source has faded out in a subsequent image obtained at UT 19:47. Further observations are under way.
GROWTH India telescope is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).
GCN Circular 24054
Subject
GRB 190404C: Swift-XRT observations
Date
2019-04-05T15:16:19Z (6 years ago)
From
Valerio D'Elia at ASDC <valerio.delia@ssdc.asi.it>
P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC),
A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:
Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 190404C (Yamada et al. 2019, GCN circ. 24049)in a series of
observations tiled on the sky. The total exposure time is 4.9 ks,
distributed over 4 tiles; the maximum exposure at a single sky location
was 3.4 ks. The data were collected between T0+7.4 ks and T0+19.1 ks,
and are entirely in Photon Counting (PC) mode.
Three uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit. No source shows definitive signs of
fading, despite Source 3, which is the brightest, marginally weakened
(at the 2.7 sigma level) during the observation. Therefore, at the
present time we cannot safely identify the afterglow. Details of these
sources are given below:
Source 1:
RA (J2000.0): 221.0760 = 14:44:18.23
Dec (J2000.0): -22.6488 = -22:38:55.5
Error: 6.1 arcsec (radius, 90% conf.)
Count-rate: (6.3 [+3.2, -2.4])e-3 ct s^-1
Distance: 1015 arcsec from MAXI position.
Flux: (3.0 [+1.5, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 2:
RA (J2000.0): 221.0110 = 14:44:2.63
Dec (J2000.0): -22.5140 = -22:30:50.3
Error: 13.5 arcsec (radius, 90% conf.)
Count-rate: (6.8 [+3.8, -2.8])e-3 ct s^-1
Distance: 1006 arcsec from MAXI position.
Flux: (5.4 [+3.0, -2.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 3:
RA (J2000.0): 220.84256 = 14:43:22.21
Dec (J2000.0): -22.66386 = -22:39:49.9
Error: 2.8 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: 0.0236 [+0.0041, -0.0038] ct s^-1
Distance: 245 arcsec from MAXI position.
Flux: (5.99 [+1.03, -0.98])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
We do not find any X-ray object at the position of the optical
candidate reported by Waratkar et al. 2019 (GCN circ. 24051), the
closest source being Source 1 at a distance of 4.3 arcmin. The XRT
upper limit at the position of the GROWTH candidate is ~7e-3 ct s^-1.
The UVOT upper limit at the same position is ~ 21 mag in the U band.
The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00079.
This circular is an official product of the Swift-XRT team.
GCN Circular 24056
Subject
GRB190404C: Counterpart retraction
Date
2019-04-06T03:35:57Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
Gaurav Waratkar(IITB), Harsh Kumar (IITB), Viraj Karambelkar (IITB), Tsewang Stanzin (IAO, IIA), Varun Bhalerao (IITB), G.C. Anupama (IIA) report on behalf of the GROWTH-India collaboration:
Further analysis of GROWTH-India data reveals that the reported object is actually not a counterpart, but asteroid 2010 FQ3. A fainter object seen in subsequent images was a background star. We hereby retract GCN 24051.
GCN Circular 24062
Subject
GRB 190404C: Swift-XRT afterglow detection
Date
2019-04-08T14:57:46Z (6 years ago)
From
Valerio D'Elia at ASDC <valerio.delia@ssdc.asi.it>
P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC),
A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the
MAXI-detected burst GRB 190404C (Yamada et al., GCN Circ. 24049). The
observations now extend from T0+7.4 ks to T0+335.5 ks.
Of the sources reported by D'Avanzo et al. (GCN Circ. 24054), "Source
3" is fading with 3-sigma significance, and is therefore likely the GRB
afterglow. Using 1249 s of PC mode data and 2 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 = 220.84256, -22.66386
which is equivalent to:
RA (J2000): 14h 43m 22.21s
Dec(J2000): -22d 39' 49.9"
with an uncertainty of 2.8 arcsec (radius, 90% confidence). This
position is 4.1 arcmin from the MAXI position.
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.72 (+0.39, -0.22).
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020887.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00079.
This circular is an official product of the Swift-XRT team.
GCN Circular 24089
Subject
GRB 190404C: MITSuME Akeno and Okayama optical upper limits
Date
2019-04-10T11:53:08Z (6 years ago)
From
Adachi Ryo at Tokyo Institute of Tech <adachi@hp.phys.titech.ac.jp>
R. Adachi, M. Niwano, K. L. Murata, K. Iida, M. Oeda,
K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We performed tiling observation for the error region of GRB 190404C
(S. Yamada et al., GCN Circular #24049)
with an optical tri-color (g', Rc, and Ic) camera attached to
the MITSuME 50cm telescopes at Akeno Observatory
and Okayama Astrophysical Observatory, in Japan.
The follow up observation started at 2019-04-04 13:36:27 UT, 1,339 sec
after the trigger.
Our tiling observation covered almost 95% of the MAXI/GSC error box
(S. Yamada et al., GCN Circular #24049).
We did not find any new point source within the Swift XRT error circle
(P. D'Avanzo et al. GCN #24054, #24062) in all three bands.
Since the brightness source near the XRT error circle(~9 arcsec), the
obtained upper limit is very shallow.
The obtained 5 sigma upper limits of the optical counterpart are
summarize below:
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
1339 13:42:06 480 >13.1 >12.4 >11.9
-------------------------------------------------------------------------------------------------------
Furthermore, compared our co-added images with GSC2.3 catalog and
UCAC4 catalog, we found no bright optical transient in the observed
region.
Because 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 start observation time(UT)
--------------------------------------------------------------------------------------------
Field 1 14:42:36, -22:46:14 25.7 x 25.9 g' > 17.0, Rc > 17.2,
Ic > 17.1 13:36:27
Field 2 14:43:08, -22:37:04 25.7 x 25.9 g' > 17.4, Rc > 17.6,
Ic > 17.4 13:47:51
Field 3 14:43:03, -22:14:27 26.0 x 25.0 g' > 17.8, Rc > 18.0,
Ic > 17.5 14:47:19
Field 4 14:44:50, -22:41:11 23.3 x 23.7 g' > 15.6, Rc > 15.6,
Ic > 15.7 14:47:06
Field 5 14:41:24, -22:15:23 23.3 x 24.3 g' > 18.0, Rc > 18.0,
Ic > 17.5 16:24:11
Field 6 14:42:17, -22:30:00 24.0 x 23.6 g' > 18.1, Rc > 18.1,
Ic > 17.5 17:57:11
Field 7 14:43:12, -22:17:05 25.4 x 25.7 g' > 17.2, Rc > 17.3,
Ic > 17.1 15:46:23
Field 8 14:44:14, -22:27:57 25.8 x 25.9 g' > 17.7, Rc > 17.3,
Ic > 16.9 18:25:06
Field 9 14:41:18, -22:20:50 25.4 x 25.7 g' > 17.6, Rc > 17.7,
Ic > 17.1 19:28:34
Field 10 14:43:18, -22:41:18 23.3 x 23.7 g' > 18.4, Rc > 18.4,
Ic > 17.7 15:25:47
--------------------------------------------------------------------------------------------
We used UCAC4 catalog for flux calibration.