Gamma-ray Burst 190106A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Sun 06 Jan 19 13:35:00 UT 
NOTICE_TYPE:     Swift-BAT GRB Position 
TRIGGER_NUM:     882252,   Seg_Num: 0 
GRB_RA:           29.886d {+01h 59m 33s} (J2000), 
                  30.153d {+02h 00m 37s} (current), 
                  29.185d {+01h 56m 44s} (1950) 
GRB_DEC:         +23.857d {+23d 51' 24"} (J2000), 
                 +23.948d {+23d 56' 54"} (current), 
                 +23.615d {+23d 36' 52"} (1950) 
GRB_ERROR:       3.00 [arcmin radius, statistical only] 
GRB_INTEN:       1783 [cnts]    Image_Peak=127 [image_cnts] 
TRIGGER_DUR:     0.512 [sec]    
TRIGGER_INDEX:   124     E_range: 25-100 keV
BKG_INTEN:       18768 [cnts]
BKG_TIME:        48873.79 SOD {13:34:33.79} UT
BKG_DUR:         8 [sec] 
GRB_DATE:        18489 TJD;     6 DOY;   19/01/06
GRB_TIME:        48884.61 SOD {13:34:44.61} UT
GRB_PHI:         -149.60 [deg]
GRB_THETA:        33.55 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.21 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  -1  +0  +0 +33  +0
SUN_POSTN:       287.28d {+19h 09m 08s}  -22.49d {-22d 29' 06"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.07d {+19h 32m 16s}  -21.33d {-21d 19' 54"}
MOON_DIST:       104.64 [deg] 
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.
COMMENTS:        This is a rate trigger.
COMMENTS:        A point_source was found.
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This does not match any source in the ground catalog.
COMMENTS:        This is a GRB.
COMMENTS:        This trigger occurred at longitude,latitude = 107.29,-18.42 [deg].

red DSS finding chart ps-file

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Sun 06 Jan 19 13:36:29 UT 
NOTICE_TYPE:     Swift-XRT Position 
TRIGGER_NUM:     882252,   Seg_Num: 0 
GRB_RA:           29.8808d {+01h 59m 31.39s} (J2000), 
                  30.1479d {+02h 00m 35.49s} (current), 
                  29.1800d {+01h 56m 43.19s} (1950) 
GRB_DEC:         +23.8467d {+23d 50' 48.1"} (J2000), 
                 +23.9384d {+23d 56' 18.1"} (current), 
                 +23.6045d {+23d 36' 16.0"} (1950) 
GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment] 
GRB_INTEN:       1.98e-08 [erg/cm2/sec] 
GRB_SIGNIF:      6.00 [sigma] 
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48966.39 SOD {13:36:06.39} UT,   81.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.18 261.55 243.52
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       287.28d {+19h 09m 08s}  -22.49d {-22d 29' 05"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.08d {+19h 32m 19s}  -21.33d {-21d 19' 51"}
MOON_DIST:       104.62 [deg] 
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.44 [deg] galactic lon,lat of the burst
ECL_COORDS:       36.13, 10.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.
COMMENTS:        The XRT position is 0.67 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:36:39 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     882252,   Seg_Num: 0
GRB_RA:           29.8808d {+01h 59m 31.3s} (J2000),
                  30.1479d {+02h 00m 35.4s} (current),
                  29.1800d {+01h 56m 43.1s} (1950)
GRB_DEC:         +23.8467d {+23d 50' 48.1"} (J2000),
                 +23.9384d {+23d 56' 18.1"} (current),
                 +23.6045d {+23d 36' 16.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       36 [cnts]
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48966.39 SOD {13:36:06.39} UT,   81.8 [sec] since BAT Trigger Time
CENTROID_X:      287.77,  raw= 288  [pixels]
CENTROID_Y:      319.74,  raw= 320  [pixels]
ROLL:            253.44 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   50.31
GRB_POS_XRT_Z:   -43.91
IMAGE_URL:       sw00882252000msxps_rw.img
SUN_POSTN:       287.29d {+19h 09m 08s}  -22.49d {-22d 29' 05"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.08d {+19h 32m 20s}  -21.33d {-21d 19' 51"}
MOON_DIST:       104.61 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.44 [deg] galactic lon,lat of the burst
ECL_COORDS:       36.13, 10.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:36:41 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     882252,   Seg_Num: 0
GRB_RA:           29.8808d {+01h 59m 31.3s} (J2000),
                  30.1479d {+02h 00m 35.4s} (current),
                  29.1800d {+01h 56m 43.1s} (1950)
GRB_DEC:         +23.8467d {+23d 50' 48.1"} (J2000),
                 +23.9384d {+23d 56' 18.1"} (current),
                 +23.6045d {+23d 36' 16.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       36 [cnts]
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48966.39 SOD {13:36:06.39} UT,   81.8 [sec] since BAT Trigger Time
CENTROID_X:      287.77,  raw= 288  [pixels]
CENTROID_Y:      319.74,  raw= 320  [pixels]
ROLL:            253.44 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   50.31
GRB_POS_XRT_Z:   -43.91
IMAGE_URL:       sw00882252000msxps_rw.img
SUN_POSTN:       287.29d {+19h 09m 08s}  -22.49d {-22d 29' 05"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.08d {+19h 32m 20s}  -21.33d {-21d 19' 51"}
MOON_DIST:       104.61 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.44 [deg] galactic lon,lat of the burst
ECL_COORDS:       36.13, 10.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:38:33 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     882252,   Seg_Num: 0
GRB_RA:           29.886d {+01h 59m 33s} (J2000),
                  30.153d {+02h 00m 37s} (current),
                  29.185d {+01h 56m 44s} (1950)
GRB_DEC:         +23.857d {+23d 51' 24"} (J2000),
                 +23.948d {+23d 56' 54"} (current),
                 +23.615d {+23d 36' 52"} (1950)
GRB_DATE:        18489 TJD;     6 DOY;   19/01/06
GRB_TIME:        48884.61 SOD {13:34:44.61} UT
TRIGGER_INDEX:   124
GRB_PHI:         -149.60 [deg]
GRB_THETA:        33.55 [deg]
DELTA_TIME:      39.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.21 [sigma]
IMAGE_SIGNIF:    8.34 [sigma]
LC_URL:          sw00882252000msb.lc
SUN_POSTN:       287.29d {+19h 09m 09s}  -22.48d {-22d 29' 05"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.10d {+19h 32m 24s}  -21.33d {-21d 19' 47"}
MOON_DIST:       104.61 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 107.29,-18.42 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:39:03 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.887d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.861d {+23d 51' 39"} (J2000)
POINT_ROLL:      253.439d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48974.79 SOD {13:36:14.79} UT,   90.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.654
N_STARS:         29
X_OFFSET:        488 [pixels]
Y_OFFSET:        496 [pixels]
X_MAX:           1447 [pixels]
Y_MAX:           1455 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00882252000msufc0090.fits
SUN_POSTN:       287.29d {+19h 09m 09s}  -22.48d {-22d 29' 05"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.10d {+19h 32m 25s}  -21.33d {-21d 19' 46"}
MOON_DIST:       104.61 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:39:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.887d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.861d {+23d 51' 39"} (J2000)
POINT_ROLL:      253.439d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48974.79 SOD {13:36:14.79} UT,   90.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.654
N_STARS:         29
X_OFFSET:        488 [pixels]
Y_OFFSET:        496 [pixels]
X_MAX:           1447 [pixels]
Y_MAX:           1455 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00882252000msufc0090.fits
SUN_POSTN:       287.29d {+19h 09m 09s}  -22.48d {-22d 29' 05"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.11d {+19h 32m 25s}  -21.33d {-21d 19' 46"}
MOON_DIST:       104.60 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:40:36 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.887d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.861d {+23d 51' 39"} (J2000)
ROLL:            253.439d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48974.79 SOD {13:36:14.79} UT,   90.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     568474597
X_OFFSET:        825 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0113.fits
SUN_POSTN:       287.29d {+19h 09m 09s}  -22.48d {-22d 29' 04"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.12d {+19h 32m 28s}  -21.33d {-21d 19' 43"}
MOON_DIST:       104.59 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:40:50 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.887d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.861d {+23d 51' 39"} (J2000)
ROLL:            253.439d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48974.79 SOD {13:36:14.79} UT,   90.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     568474597
X_OFFSET:        825 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0113.fits
SUN_POSTN:       287.29d {+19h 09m 09s}  -22.48d {-22d 29' 04"}
SUN_DIST:        110.08 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.12d {+19h 32m 29s}  -21.33d {-21d 19' 43"}
MOON_DIST:       104.59 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:42:41 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     882252,   Seg_Num: 0
GRB_RA:           29.8799d {+01h 59m 31.17s} (J2000),
                  30.1470d {+02h 00m 35.27s} (current),
                  29.1791d {+01h 56m 42.97s} (1950)
GRB_DEC:         +23.8455d {+23d 50' 43.8"} (J2000),
                 +23.9372d {+23d 56' 13.7"} (current),
                 +23.6033d {+23d 36' 11.7"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         16.45 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  48971.00 SOD {13:36:11.00} UT,   86.4 [sec] since BAT Trigger Time
SUN_POSTN:       287.29d {+19h 09m 10s}  -22.48d {-22d 29' 04"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.14d {+19h 32m 33s}  -21.33d {-21d 19' 39"}
MOON_DIST:       104.57 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       36.13, 10.93 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 5.0 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #23614
V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk
V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University
R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA)
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the GRB190106.57 20 sec after notice time and 36 sec after trigger time at 2019-01-06 13:35:20 UT. On our second (10s exposure) set , obtained 61 sec after tigger time at 2019-01-06 13:35:46 UT, we found 1 optical transient within SWIFT error-box (ra=29.8792 dec=23.8567 r=0.05) brighter than 16.06.
```
  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
       66   2019-01-06 13:35:46      10   (  1h 59m 31.19s , +23d 50m 44.79s)    15.23
```
The 5-sigma upper limit has been about 16.06mag The message may be cited.
====================================================================
The galactic latitude b = -36 deg., longitude l = 143 deg. The observations made on zenit distance = 45 deg.The moon ( 0 % bright part) below the horizon (The altitude of the Moon is -50 deg. ). The sun altitude is -53.8 deg. The object can be observed till 2019-01-07 18:34:53
GCN Circular #23615
E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), C. Gronwall (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team:
At 13:34:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190106A (trigger=882252). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 29.886, +23.857, which is
```
   RA(J2000)  =  01h 59m 33s
   Dec(J2000) = +23d 51' 24"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a duration of about 100 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~10 sec after the trigger.
The XRT began observing the field at 13:36:06.3 UT, 81.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 29.87964, 23.84516 which is equivalent to:
```
   RA(J2000)  = 01h 59m 31.11s
   Dec(J2000) = +23d 50' 42.6"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 47 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density.
The initial flux in the 0.1 s image was 1.98e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 90 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	01:59:31.18 =  29.87993
  DEC(J2000) = +23:50:44.0  =  23.84555
```
with a 90%-confidence error radius of about 0.61 arc sec. This position is 5.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 16.45 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.09.
Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:47:53 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 50"} (J2000)
POINT_ROLL:      253.441d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49188.05 SOD {13:39:48.05} UT,   303.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.761
N_STARS:         14
X_OFFSET:        505 [pixels]
Y_OFFSET:        424 [pixels]
X_MAX:           1464 [pixels]
Y_MAX:           1383 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00882252000msufc0303.fits
SUN_POSTN:       287.29d {+19h 09m 10s}  -22.48d {-22d 29' 02"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.18d {+19h 32m 44s}  -21.32d {-21d 19' 29"}
MOON_DIST:       104.54 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:48:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 50"} (J2000)
POINT_ROLL:      253.441d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49188.05 SOD {13:39:48.05} UT,   303.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.761
N_STARS:         14
X_OFFSET:        505 [pixels]
Y_OFFSET:        424 [pixels]
X_MAX:           1464 [pixels]
Y_MAX:           1383 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00882252000msufc0303.fits
SUN_POSTN:       287.29d {+19h 09m 11s}  -22.48d {-22d 29' 02"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.19d {+19h 32m 44s}  -21.32d {-21d 19' 28"}
MOON_DIST:       104.53 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:49:17 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 50"} (J2000)
ROLL:            253.441d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49188.05 SOD {13:39:48.05} UT,   303.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     568474810
X_OFFSET:        825 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0326.fits
SUN_POSTN:       287.29d {+19h 09m 11s}  -22.48d {-22d 29' 02"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.20d {+19h 32m 47s}  -21.32d {-21d 19' 26"}
MOON_DIST:       104.53 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:49:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 50"} (J2000)
ROLL:            253.441d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49188.05 SOD {13:39:48.05} UT,   303.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     568474810
X_OFFSET:        825 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0326.fits
SUN_POSTN:       287.29d {+19h 09m 11s}  -22.48d {-22d 29' 01"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.20d {+19h 32m 47s}  -21.32d {-21d 19' 26"}
MOON_DIST:       104.52 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:48:27 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     882252,   Seg_Num: 0
GRB_RA:           29.8804d {+01h 59m 31.29s} (J2000),
                  30.1475d {+02h 00m 35.39s} (current),
                  29.1796d {+01h 56m 43.09s} (1950)
GRB_DEC:         +23.8448d {+23d 50' 41.2"} (J2000),
                 +23.9365d {+23d 56' 11.2"} (current),
                 +23.6026d {+23d 36' 09.2"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49178.00 SOD {13:39:38.00} UT,   293.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       287.29d {+19h 09m 11s}  -22.48d {-22d 29' 02"}
SUN_DIST:        110.06 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.19d {+19h 32m 45s}  -21.32d {-21d 19' 28"}
MOON_DIST:       104.52 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.44 [deg] galactic lon,lat of the burst
ECL_COORDS:       36.13, 10.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:53:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 49"} (J2000)
POINT_ROLL:      253.442d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49743.08 SOD {13:49:03.08} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.774
N_STARS:         39
X_OFFSET:        265 [pixels]
Y_OFFSET:        184 [pixels]
X_MAX:           1704 [pixels]
Y_MAX:           1623 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00882252000msufc0858.fits
SUN_POSTN:       287.30d {+19h 09m 12s}  -22.48d {-22d 29' 00"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.24d {+19h 32m 57s}  -21.32d {-21d 19' 17"}
MOON_DIST:       104.49 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:54:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 49"} (J2000)
POINT_ROLL:      253.442d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49743.08 SOD {13:49:03.08} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.774
N_STARS:         39
X_OFFSET:        265 [pixels]
Y_OFFSET:        184 [pixels]
X_MAX:           1704 [pixels]
Y_MAX:           1623 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00882252000msufc0858.fits
SUN_POSTN:       287.30d {+19h 09m 12s}  -22.48d {-22d 29' 00"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.24d {+19h 32m 58s}  -21.32d {-21d 19' 16"}
MOON_DIST:       104.49 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:55:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 49"} (J2000)
ROLL:            253.442d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49743.08 SOD {13:49:03.08} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     568475365
X_OFFSET:        824 [pixels]
Y_OFFSET:        743 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       984
Y_GRB_POS:       903
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0881.fits
SUN_POSTN:       287.30d {+19h 09m 12s}  -22.48d {-22d 29' 00"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.25d {+19h 33m 00s}  -21.32d {-21d 19' 14"}
MOON_DIST:       104.48 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Jan 19 13:55:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     882252,   Seg_Num: 0
POINT_RA:         29.889d {+01h 59m 33s} (J2000)
POINT_DEC:       +23.864d {+23d 51' 49"} (J2000)
ROLL:            253.442d
IMG_START_DATE:  18489 TJD;     6 DOY;   19/01/06
IMG_START_TIME:  49743.08 SOD {13:49:03.08} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     568475365
X_OFFSET:        824 [pixels]
Y_OFFSET:        743 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       984
Y_GRB_POS:       903
BINNING_INDEX:   1
IM_URL:          sw00882252000msuni0881.fits
SUN_POSTN:       287.30d {+19h 09m 12s}  -22.48d {-22d 29' 00"}
SUN_DIST:        110.07 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      293.25d {+19h 33m 00s}  -21.32d {-21d 19' 14"}
MOON_DIST:       104.48 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      142.37,-36.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       36.14, 10.95 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #23616
V. Lipunov, A.Kuznetsov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University
R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA)
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the GRB190106.57 (Swift BAT alert, GCN 23615) 20 sec after notice time and 36 sec after trigger time at 2019-01-06 13:35:20 UT. On our first (10s exposure) set we found optical transient within SWIFT BAT error-box (ra=29.8792 dec=23.8567 r=0.05). The 5-sigma upper limit has been about 16.5mag
RA, DEC = 01h 59m 31.20s +23d 50m 44.04s mag = 16.0 The automatical photometry are:
```
start time	     coord2000		  Band	 mag	emag  exp

13:35:20.0   1h 59m 31.17s +23d 50m 44.5s   P   16.2    0.20   10
13:35:46.6   1h 59m 31.19s +23d 50m 44.8s   P	15.2	0.14   10
13:36:12.6   1h 59m 31.23s +23d 50m 44.1s   P	15.8	0.15   20
13:36:47.8   1h 59m 31.19s +23d 50m 44.6s   P	16.2	0.17   20
13:37:24.9   1h 59m 31.23s +23d 50m 44.5s   P	15.8	0.11   30
13:38:08.7   1h 59m 31.18s +23d 50m 44.2s   P	15.4	0.08   40 
13:39:03.1   1h 59m 31.17s +23d 50m 44.2s   P	15.7	0.07   50
13:40:07.0   1h 59m 31.18s +23d 50m 44.1s   P	15.5	0.09   60
13:41:35.5   1h 59m 31.20s +23d 50m 44.0s   P	15.6	0.10   60
13:43:03.7   1h 59m 31.18s +23d 50m 44.3s   P	15.9	0.11   60
13:44:28.9   1h 59m 31.18s +23d 50m 43.8s   P	16.1	0.12   60
...............................
to be continuated...
```
This optical counterpart is coincident with Swift optical object (Sonbas et al., GCN 23615).
The galactic latitude b = -36 deg., longitude l = 143 deg. The observations made on zenit distance = 45 deg.The moon ( 0 % bright part) below the horizon (The altitude of the Moon is -50 deg. ). The sun altitude is -53.7 deg. The object can be observed till 2019-01-07 18:34:53
This message may be cited, but this is the first automatic photometry. Non monotonic light curve was detected.
GCN Circular #23617
R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita, K. Shiraishi, K. Iida, M. Niwano, R. Adachi, M. Oeda, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration
We searched for the optical counterpart of GRB 190106A (Sonbas et al., GCN Circular #23615) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 13:35:33 UT which corresponds to 49 sec after the trigger. We detected the point source at the position consistent with the Swift/UVOT observation (Sonbas et al., GCN Circular #23615) and MASTER observation (Lipunov et al., GCN Circular #23616). The measured magnitudes are listed as follows.
```
T0+[sec]    MID-UT      T-EXP[sec]        g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
~49      13:36:02.6           60               ~16.1      ~15.6   ~15.5
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used UCAC-4 catalog for flux calibration. The magnitudes are expressed in the AB system.
Further analysis is ongoing.
GCN Circular #23618
J. Mao, Y.-X. Xin, Y. Li, and J.-M. Bai (YNAO) report:
We observed the field of GRB 190106A (Sonbas et al., GCN 23615) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. Observations began about 0.5 hours after the trigger. We clearlydetected the optical source reported by Yurkov et al. (GCN 23614). The spectral observation is ongoing.
GCN Circular #23619
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 621 s of XRT Photon Counting mode data and 1 UVOT images for GRB 190106A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 29.88004, +23.84544 which is equivalent to:
```
RA (J2000): 01h 59m 31.21s
Dec (J2000): +23d 50' 43.6"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #23620
I. Reva (FAPHI), A. Pozanenko (IKI), A. Kusakin (FAPHI), S. Belkin (IKI), A. Volnova (IKI), E. Mazaeva (IKI), M. Krugov (FAPHI) report on behalf of larger GRB follow-up collaboration:
We observed the optical transient (Yurkov et al., GCN 23614; Sonbas et al., GCN 23615; Lipunov et al., GCN 23616; Itoh et al., GCN 23617) of GRB 190106A (Sonbas et al., GCN 23615) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Jan. 6 (UT) 13:45:42. Preliminary photometry of the object in the beginnig of observations is R= 16.23 +/- 0.05, and the optical transient is faded as R= 17/5 +/- 0.1 at (UT) 14:24:04. (The photometry is based on nearby USNO-B1.0 stars). Observations are continuing in R and B - filters.
GCN Circular #23622
L. P. Xin, P. P. Zhang, R. S. Zhang, J. Wang, J. Y. Wei, E. W. Liang, X. G. Wang, Y. J. Xiao, Y. G. Yang, X. M. Lu, L. Huang, H. B. Cai, Y. L. Qiu, Y. Xu, Y. J. Xiao, Y. T. Zheng, C. Wu, J. S. Deng, D. W. Xu, D. TURPIN, H. L. Li, and W. L. Dong, report:
We observed GRB 190106A ( Sonbas et al., GCN 23615 ) with GWAC-F60B 60cm optical telescope at 14:51:03 UT, Jan. 06th 2019, about 77 min after the burst.
The optical afterglow reported by ( Sonboas et al., GCN 23615; Lipunov et al., GCN 23636; Itoh et al., GCN23617; Mao et al., GCN 23618 ) is clearly detected in R band images. The brightness is 17.8mag calibrated by nearby USNO-B1.0 stars.
GWAC-F60B is operated by Guangxi university and NAOC, CAS, at Xinglong observatory, China.
Further observation is continuing.
The message may be cited.
GCN Circular #23623
Z.P. Zhu, D. Xu, Y. Wang, J.B. Zhang (NAOC), J.H. Liu, X. Zhang (XAO) report:
We observed the optical afterglow of GRB 190106A (Sonbas et al., GCN 23615) using the Xinglong-2.16m telescope equipped with BFOSC. We acquired 1x3600 s and then 1x2400 s spectra starting at 14:02:39 UT on 2019-01-06, i.e., 27.9 mins after the burst. The optical afterglow was R~16 mag at this time.
From preliminary analysis, a continuum is detected across the spectral range of 3600 - 9000 AA. A few absorption features are also detected due to Fe II, Al II, Mn II, Mg II doublet, and Mg I, at a redshift of z~0.896, which we propose as the likely redshift of the GRB.
GCN Circular #23624
U.Quadri, L.Strabla and A.Quadri report:
We imaged the field of GRB 190106A detected by SWIFT(trigger 882252) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy. Member of: AAVSO - American Association of Variable Star Observers. ISSP - Italian Supernovae Search Project. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
The observations started 6.16 hour after the GRB trigger, with our baker-Schmidt telescope D=250 mm F/D=3.
Weather conditions were good.
We co-added 2 series of 15 exposures of 60 sec each.
```
Start T0+      End T0+      Vlim
6.16 hour   6.72 hour       19.5
```
We detect the afterglow in the error box of the XRTcandidate. E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC), et al. at the following position (+/- 2 arcsec):
```
RA (J2000.0) =  01h 59m 31.50s
DEC(J2000.0) = +23� 50' 44.7"
```
The results of our photometry are:
```
------------------------------------    
     JD          V mag       Cat
------------------------------------
2458490.33004   19.130 V    UCAC4   
2458490.34077   19.344 V    UCAC4   
------------------------------------
```
Magnitudes were estimated with the UCAC4 cat. and are not corrected for galactic dust extinction.
The images are available at: http://www.osservatoriobassano.org/GRB.asp
The message may be cited.
GCN Circular #23625
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+695 sec from recent telemetry downlinks, we report further analysis of BAT GRB 190106A (trigger #882252) (Sonbas, et al., GCN Circ. 23615). The BAT ground-calculated position is RA, Dec = 29.877, 23.839 deg, which is
```
   RA(J2000)  =  01h 59m 30.6s 
   Dec(J2000) = +23d 50' 20.8" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 65%.
The mask-weighted light curve shows it started at ~T-10sec, with a pair of overlapping FRED-like peaks at ~T+2 and ~T+10 sec, then a long decay and two more peaks at ~T+57 and ~T+76 sec, and returning to baseline at ~T+125 sec. T90 (15-350 keV) is 76.8 +- 2.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.17 to T+99.72 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.34 +- 0.21, and Epeak of 120 +- 83 keV (chi squared 37.25 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 6.0 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+75.28 sec in the 15-150 keV band is 5.5 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.64 +- 0.05 (chi squared 43.44 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/882252/BA/
GCN Circular #23626
N. P. M. Kuin (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190106A 90 s after the BAT trigger (Sonbas et al., GCN Circ. 23615). A source consistent with the XRT position (Goad et al. GCN Circ. 23619) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
    RA  (J2000) =  01:59:31.16 =  29.87985 (deg.)
    Dec (J2000) = +23:50:43.9  =  23.84552 (deg.)
```
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
The source was also detected by MASTER (Yurkov et al, GCN Circ. 23614,23616), MITSuME (Itoh et al, GCN Circ. 23617), GMG (Mao et al, GCN Circ. 23618), TSHAO (Reva et al, GCN Circ. 23620), GWAC-F60B (Xin et al, GCN Circ. 23622), Xinglong (Zhu et al, GCN Circ. 23623) who report a redshift of z~0.896 and Bassano Bresciano Observatory (Quadri et al, GCN Circ. 23624).
Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               90          240          147         16.64 +/- 0.03
v                  633          653           20         16.54 +/- 0.16
b                  559          579           20         16.70 +/- 0.09
u                  304          553          246         15.97 +/- 0.03
w1                 682          702           20         17.36 +/- 0.29
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #23627
Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), S. Guziy (Nikolaev Astronomical Observatory) and D. Xiong, Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan Nacional Astronomical Observatory) on behalf of a larger collaboration, report:
Following the detection of GRB 190106A by Swift (Sonbas et al. GCNC 23615), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical Observatory (China) triggered alert at 15:12:56 UT (~1.6 hr after trigger). The reported optical afterglow (Yurkov et al. GCNC 23614, Lipunov et al. GCNC 23616, Itoh et al. GCNC 23617, Mao et al. GCNC 23618, Reva et al. GCNC 23620 and Xin et al. 23622) is still clearly detected within the refined XRT position (Goad et al. GCNC 23619). A preliminary photometry yields a magnitude of 19.4 +/- 0.1 (g-band). Observations are ongoing.
GCN Circular #23628
A. Noschese (AC-OASDG), L. Izzo (IAA-CSIC), A. Di Dato and L. D’Avino (AC-OASDG) report:
We observed the field of GRB 190106A (Sonbas et al. GCN 23615) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( https://goo.gl/Dqvqhf ).
We obtained a series of 3x180 s images in the Rc filter, starting at 21:44:38 UT, ~ 8.17 hrs after the GRB detection. In our stacked image, we find a source at the position of the observed optical counterpart (Lipunov et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) for which we measure a magnitude of Rc(AB) = 19.47 +/- 0.10 mag. The calibration was performed using nearby stars in the USNO B1 catalog.
GCN Circular #23620
D. Xu, Z.P. Zhu, Y. Wang, J.B. Zhang (NAOC), J.H. Liu, X. Zhang (XAO) report:
We have re-reduced the 3600s+3000s spectra taken from the Xinglong-2.16m telescope (Zhu et al., GCN 23623), with the calibration frames taken in the same night. The Signal-to-Noise of the spectrum increased compared with the previous 3600s one, and the resolution is not high due to seeing~2.0".
We only consider relatively prominent absorption features and thus only six features are left, which can be interpreted as Fe II 1547.62, 1550.19, 2585.88, 2599.40, and Mg II doublet 2795.53, 2802.71 (wavelength in air), at an updated and consistent redshift of z=1.86.
GCN Circular #23630
J. Mao, Y.-X. Xin, Y. Li, J.-M. Bai (YNAO), J. Wang, and L. P. Xin (NAOC) report:
We observed the afterglow of GRB 190106A with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. The spectral observations began about 0.5 hours after the trigger. The spectrum has excellent S/N. Some absorption lines, such as SiIV 1394, SiII 1527, AlII 1671, AlIII 1855/1863, CrII+ZnII 2062, and FeII 2344/2383, were clearly detected. This indicates a redshift of about 1.86, consistent with the result of Xu et al. (GCN. 23629). Moreover, we note a possible broad emission feature around 4500A, and further analysis is ongoing.
GCN Circular #23632
P. Schady (Univ. of Bath), D. Xu (NAOC), K. E. Heintz (Univ. of Iceland), N. R. Tanvir (Univ. Leicester), D. B. Malesani (DAWN/NBI and DARK/NBI), D. A. Kann (HETH/IAA-CSIC), R. Sanchez-Ramirez (INAF/IAPS) and K. Wiersema (Univ. of Warwick) report:
We observed the optical counterpart of GRB 190106A (Sonbas et al., GCN #23615; Yurkov et al., GCN #23614) with the ESO-VLT UT2 (Kueyen) equipped with the X-shooter spectrograph, covering the wavelength range 3000-21000 AA. We acquired four 600 second spectra on 2019-01-07 between 00:53UT and 01:47UT, approximately 11 hours after the GRB. In the acquisition image we measure r = 19.47 +/- 0.02 (AB), calibrated against a nearby Pan-STARRS object.
We detect several absorption features at a common redshift z = 1.859, consistent with the value reported by Xu et al. (GCN #23629) and Mao et al. (GCN #23630). In addition to the absorption lines reported by Xu et al. and Mao et al., we also detect O I, C II, Mg I, and C IV, all at the same redshift, as well a broad feature due to H I Lyalpha absorption.
We acknowledge Steffen Mieske and Joe Anderson at Paranal for their excellent help in obtaining these observations.
GCN Circular #23633
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU) and V. Yurkov report on behalf of the Swift-XRT team: report on behalf of the Swift-XRT team:
We have analysed 5.7 ks of XRT data for GRB 190106A (Yurkov et al. GCN Circ. 23614), from 85 s to 44.7 ks after the BAT trigger. The data comprise 254 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 23619).
The late-time light curve (from T0+11.7 ks) can be modelled with a power-law decay with a decay index of alpha=1.02 (+/-0.11).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.06 (+0.06, -0.05). The best-fitting absorption column is 1.9 (+/-1.1) x 10^21 cm^-2, at a redshift of 1.86, in addition to the Galactic value of 1.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.95 (+0.09, -0.06) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Galactic foreground: 1.0 x 10^21 cm^-2
Intrinsic column:    1.0 (+1.6, -0.0) x 10^21 cm^-2 at z=1.86
Photon index:	     1.95 (+0.09, -0.06)
```
If the light curve continues to decay with a power-law decay index of 1.02, the count rate at T+24 hours will be 0.096 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x 10^-12 (4.2 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00882252.
This circular is an official product of the Swift-XRT team.
GCN Circular #23634
J. Mao, Y.-X. Xin, Y. Li, J.-M. Bai (YNAO) report:
We observed the afterglow of GRB 190106A with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories in the second night. The observation began at UT 12:47:01, 7th, Jan, 2019, about 23.2 hours after the trigger. We still clearly detected the source. A preliminary measurement provided a magnitude of R~19.7. We suggest other telescopes to keep on observations.
GCN Circular #23635
IERCOO/ICSP optical observation of GRB 190106A
Sandip K. Chakrabarti, Argha Sil, Shyam Sarkar, Ashim Sarkar, D. Bhowmick (Indian Centre for Space Physics)
We observed GRB 190106A using 0.61m reflector of our observatory at Sitapur, West Bengal, India. The observation was with R, V, and B filters in a short interval at around 16:45UT on 6th January, 2019, i.e., about three hours after the BAT trigger (Sonbas et al. 2019; GCN 23615). Using two exposures each of 90s in R and in V, we obtained the magnitudes of 17.83+/-0.25 and 18.45 +/- 0.23 respectively. Using one 90s exposure in B, we obtained the magnitude of 18.81+/-0.39. Using triangulation, we obtained the location of the afterglow to be RA(J2000) = 01h 59m 31.17s, Dec(J2000) = +23d 50m 43.94s with two pixel error 0.46s. Three sigma method was used to estimate the magnitudes with a calibrator J01593557 +2348527 which is of V mag ~12.5. After 24 hours of the BAT trigger we do not detect the afterglow on 7th Jan. at 13:30UT. The details of images and other results will be in http:/csp.res.in.
GCN Circular #23636
Z.P. Zhu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.H. Liu (XAO) report:
We monitored the optical afterglow of GRB 190106A (e.g., Sonbas et al., GCN 23615) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China and the Xinglong-2.16m telescope.
The observations of NEXT-0.6m started at 13:57:21 UT on 2019-01-06 (i.e., 0.38 hr post-burst) and ended at 19:48:25 UT on 2019-01-06 (i.e., 5.97 post-burst), with a series of 60s, 90s, 120s, 200s, and 300s exposures in the R-band. The afterglow had R=16.9+/-0.1 mag at the beginning, and rather smoothly decayed to R=19.1+/-0.1 mag at the end, calibrated with nearby SDSS stars.
The Xinglong-2.16m observations were carried out at 12:54:46 UT on 2019-01-07, i.e, 23.33 hr post-burst, with 5x360s in the R-band. The afterglow has decayed to R=19.9+/-0.1 mag, calibrated with the same reference stars.
The joint NEXT-0.6m and Xinglong-2.16m dataset shows that so far the afterglow R-band lightcurve has been decaying, and following a single powerlaw of F ~ t^-alpha, where alpha~0.64.
GCN Circular #23637
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report:
The� GRB 190106A (Swift detection: Sonbas et al., GCN 23615; Palmer et al., GCN 23625) triggered Konus-Wind at T0=48887.602 s UT (13:34:47.602).
The burst light curve shows a multi-peaked structure which starts at ~T0-5 s and has a total duration of ~79 s. The emission is seen up to ~2 MeV.
As observed by Konus-Wind, the burst had a fluence of 1.12(-0.17,+0.25)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0-0.044 s, of 1.81(-0.89,+1.19)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+82.176 s) is best fit in the 20 keV - 16 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with� alpha = -1.00(-0.50,+0.63), and Ep = 171(-42,+90) keV (chi2 = 81/98 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.31 (chi2 = 81/97 dof).
The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 1.2 MeV range by the power law with exponential cutoff model: with� alpha = -1.15(-0.50,+0.66), and Ep = 216(-66,+308) keV (chi2 = 55/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.85 (chi2 = 55/59 dof).
Assuming the redshift z=1.859 (Xu et al., GCN 23629; Mao et al., GCN 23630; Schady et al., GCN 23632) and a standard cosmology model with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is 9.96(-1.55,+2.25)x10^52 erg, the peak luminosity L_iso is 4.62(-2.28,+3.03)x10^52 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is 489(-120,+257) keV, and the rest-frame peak energy of the 'peak' spectrum, Ep,p,z, is 618(-189, 881) keV. With these energetics, the burst lies within the 68% prediction bands for both 'Amati' and 'Yonetoku' relations built for the sample of 138 long KW GRBs with known redshifts (Tsvetkova et al., ApJ 850 161, 2017).
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB190106_T48887/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #23638
I. Reva (FAPHI), A. Pozanenko (IKI), S. Belkin (IKI), A. Volnova (IKI), E. Mazaeva (IKI), E. Klunko (ISTP), A. Kusakin (FAPHI), M. Krugov (FAPHI) report on behalf of IKI FuN collaboration:
We continue the observations of the optical afterglow (e.g. Lipunov et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) of the GRB 190106A (Sonbas et al., GCN 23615) with Zeiss-1000 telescope of Tien Shan Astronomical Observatory. We obtained several images in R-filter starting on Jan. 7 (UT) 12:57:20. Preliminary photometry of the afterglow is R= 20.07 +/- 0.06 at (UT, mid time) 13:40:10 which is compatible with the photometry reported in GCN 23636 (Zhu et al.) The photometry is based on nearby USNO-B1.0 stars.
GCN Circular #23640
S. Belkin (IKI), E. Klunko (ISTP), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI), I. Reva (FAPI) report on behalf of IKI-FuN:
We observed the optical afterglow (e.g. Lipunov et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) of the GRB 190106A (Sonbas et al., GCN 23615) with AZT-33IK telescope of Sayan observatory (Mondy). We started observations on Jan. 06 (UT) 13:53:44, i.e. 19 minutes after burst trigger and continued observations on Jan. 07, Jan. 08 in R-filter. Preliminary light curve obtained on Jan. 06 observation can be found in http://grb.rssi.ru/GRB190106A/GRB190106A_LC_R.png
The photometry is based on nearby SDSS stars
```
SDSS-DR12_id              R(Lupton)
J015920.22+235150.7 16.475
J015929.35+235237.5 15.774
```
GCN Circular #23660
L. Izzo, D. A. Kann (HETH-IAA/CSIC) A. de Ugarte Postigo (DARK/NBI & HETH-IAA/CSIC), M. Blazek, C. C. Thoene (HETH-IAA/CSIC) report:
We observed the field of GRB 190106A (Deich et al.; GCN Circ. 22710) with the 2-m Liverpool Telescope located in La Palma, Spain. Observations started on January 6th at 21:10:35 UT (8.0 hours after the GRB trigger) and we obtained a series of 5x60s images in the g, r and i filters.
We clearly detect the optical afterglow (Lipunov et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627, Noschese et al. GCN 23628) for which we measure the following magnitudes:
```
g = 19.47 +- 0.03
r = 18.90 +- 0.09
i = 18.49 +- 0.26
```
The calibration was performed using nearby SDSS stars.
GCN Circular #23661
S. Belkin (IKI), A. Pozanenko (IKI), P. Minaev (IKI), E. Klunko (ISTP), I. Reva (FAPI), M. Krugov (FAPI), V. Rumyantsev (CrAO), R. Ya. Inasaridze (AbAO), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-FuN:
We continue observations the optical afterglow (e.g. Lipunov et al. GCN 23616, Itoh et al. GCN 23617, Mao et al. GCN 23618, Reva et al., GCN 23620, Xin et al. GCN 23622, Quadri et al. GCN 23624, Hu et al. GCN 23627) of the GRB 190106A (Sonbas et al., GCN 23615) with AZT-33IK telescope of Sayan observatory (Mondy), Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory, and AS-32 (0.7m) telescope of Abastumani Observatory. Preliminary photometry of the afterglow is following.
```
Date       UT start t-T0    Filter Exp.   OT    Err. Observatory
                    (mid, days) (s)

2019-01-07 17:27:12 1.19251 R      63*60  20.27 0.08  AbAO
2019-01-08 11:07:16 1.91774 R      30*120 21.11 0.13  Mondy
2019-01-08 15:53:23 2.09628 R      12*120 21.1  0.3   CrAO
```
The photometry is based on nearby SDSS stars
```
SDSS-DR12_id              R(Lupton)
J015920.22+235150.7 16.475
J015929.35+235237.5 15.774
```
Based on our previous results (GCNs 23620, 23638, 23640) and photometry above we plot a light curve ( http://grb.rssi.ru/GRB190106A/GRB190106A_LC_R_fit.png ). We could suggest the jet break at 1.5 +/- 0.5 days.
GCN Circular #23665
M. Blazek, D. A. Kann (both HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), L. Izzo, and K. Bensch (all HETH/IAA-CSIC) report:
We observed the optical afterglow of GRB 190106A (e.g., Yurkov et al., GCN #23614), detected by Swift (Sonbas et al., GCN #23615), with with the T150 telescope of the Sierra Nevada Observatory (OSN). We obtained 18 x 300 s images in the Ic band from 5.02 to 6.47 hours after the GRB. The afterglow is well-detected in each single image. We find it decays between the beginning and end of our observing run.
```
Days	Ic mag	error

0.2091	18.54	0.05
0.2696	18.73	0.06
```
Magnitudes are given in the AB system. They were measured vs. four SDSS comparison stars, using the transformation equations of Lupton (2005), and transformed back into AB mags.
GCN Circular #23668
J. Mao, X.-L. Zhang, J.-M. Bai (YNAO) report:
We still monitor the afterglow of GRB 190106A with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. The observation began at UT 13:57:39, 9th, Jan, 2019, about 72.2 hours after the trigger. We marginally detected the source. A very preliminary measurement provided a magnitude of R~21.2.
GCN Circular #23744
S.Dichiara (UMD, NASA-GSFC), P. Gatkine (UMD), J.M. Durbak (UMD), E. Troja (UMD, NASA-GSFC), A. Kutyrev (UMD, NASA-GSFC), S. Veilleux (UMD), report on behalf of a larger collaboration:
We observed at the optical counterpart of GRB 190106A (Sonbas et al. GCN 23615) using the Large Monolithic Imager (LMI) on the 4.3m Discovery Channel Telescope (DCT) at Happy Jack, AZ. Observations start on January 08, 06:36:53 UT (about 41 hours after the Swift trigger) with SDSS r, i and z filters. We measured the following magnitudes:
```
Start Time         Exposure       Filter    Magnitude
(hs from trigger)    (s)
--------------------------------------------------------------------
41.036               3x120          r'    20.77 +- 0.03
41.157               3x120          i'    20.60 +- 0.05
41.279               3x120          z'    20.70 +- 0.15
---------------------------------------------------------------------
```
Magnitudes are calibrated against SDSS nearby stars: J015939.43+235056.5 25.7308, J015938.69+235101.6, J015933.94+235145.7 and J015923.06+235109.1. We thank the staff of the Discovery Channel Telescope for assistance with these observations.

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Jochen Greiner, last update: 16-Jan-2019 [Disclaimer]