Gamma-ray Burst 190404B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN Notice

TITLE:           GCN/MAXI NOTICE
NOTICE_DATE:     Thu 04 Apr 19 13:35:44 UT
NOTICE_TYPE:     MAXI Unknown Source Position
EVENT_ID_NUM:    577411373
EVENT_RA:        220.77d {+14h 43m 05s} (J2000),
                 221.05d {+14h 44m 12s} (current),
                 220.06d {+14h 40m 14s} (1950)
EVENT_DEC:       -22.69d {-22d 41' 12"} (J2000),
                 -22.77d {-22d 46' 04"} (current),
                 -22.48d {-22d 28' 29"} (1950)
EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX:      930.0 +- 0.0 [mCrab] 
EVENT_DATE:      18577 TJD;    94 DOY;   19/04/04
EVENT_TIME:      47674.00 SOD {13:14:34.00} UT
EVENT_TSCALE:    1s
EVENT_EBAND:     Low, 2-4 keV  
SUN_POSTN:        13.35d {+00h 53m 24s}   +5.71d {+05d 42' 53"}
SUN_DIST:        148.31 [deg]  
MOON_POSTN:        6.87d {+00h 27m 28s}   -2.18d {-02d 10' 31"}
MOON_DIST:       138.38 [deg]  
MOON_ILLUM:      1 [%]
GAL_COORDS:      334.07, 33.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      225.31, -6.56 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.

GCN Notice

 
TITLE:           GCN/MAXI NOTICE
NOTICE_DATE:     Thu 04 Apr 19 13:40:44 UT
NOTICE_TYPE:     MAXI Unknown Source Position
EVENT_ID_NUM:    577411373
EVENT_RA:        220.90d {+14h 43m 37s} (J2000),
                 221.18d {+14h 44m 43s} (current),
                 220.19d {+14h 40m 45s} (1950)
EVENT_DEC:       -22.54d {-22d 32' 05"} (J2000),
                 -22.62d {-22d 36' 56"} (current),
                 -22.32d {-22d 19' 23"} (1950)
EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX:      387.0 +- 0.0 [mCrab] 
EVENT_DATE:      18577 TJD;    94 DOY;   19/04/04
EVENT_TIME:      47674.00 SOD {13:14:34.00} UT
EVENT_TSCALE:    1s
EVENT_EBAND:     Low, 2-4 keV  
SUN_POSTN:        13.35d {+00h 53m 25s}   +5.72d {+05d 42' 58"}
SUN_DIST:        148.28 [deg]
MOON_POSTN:        6.91d {+00h 27m 37s}   -2.16d {-02d 09' 34"}
MOON_DIST:       138.40 [deg]  
MOON_ILLUM:      1 [%]
GAL_COORDS:      334.28, 33.42 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      225.38, -6.38 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.

GCN Circular #24049
S. Yamada (Kyoto U.), H. Negoro, M. Nakajima (Nihon U.), W. Iwakiri (Chuo, U.), W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, S. Nakahira, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, T. Hashimoto, A. Yoshida (AGU), Y. Tsuboi, R. Sasaki, H. Kawai, T. Sato (Chuo U.), N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Ogawa (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.), Y. Kawakubo (LSU) report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source at 13:14:08 UT on 2019 April 04. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (220.987 deg, -22.632 deg) = (14 43 56, -22 37 55) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.13 deg and 0.11 deg, respectively. The roll angle of the long axis from the north direction is 67.0 deg counterclockwise. Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners:
```
(221.159, -22.965) deg = (14 44 38, -22 57 53) (J2000)
(221.325, -22.771) deg = (14 45 17, -22 46 15) (J2000)
(220.273, -22.002) deg = (14 41 05, -22 00 07) (J2000)
(220.107, -22.196) deg = (14 40 25, -22 11 45) (J2000)
```
There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 378 +- 40 mCrab (4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 11:41 UT with an upper limit of 20 mCrab.
Note that we rename GRB 190404B in the MAXI new-transient ML GRB 190404C.
GCN Circular #24051
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
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
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
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
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.

GCN Circular #24120
H. Negoro (Nihon U.) report on behalf of the MAXI team:
The GRB names of 140404B/190404B (Nakajima et al. GCN Circ. 24048) and 140404C/190404C (Yamada et al. GCN Circ. 24049) should be 190404A and 190404B, respectively. I sincerely apologize for the late correction and for any confusion caused.

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Jochen Greiner, last update: 28-Apr-2019 [Disclaimer]