- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 11 Feb 19 16:55:20 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 888648, Seg_Num: 0
GRB_RA: 196.675d {+13h 06m 42s} (J2000),
196.893d {+13h 07m 34s} (current),
196.106d {+13h 04m 25s} (1950)
GRB_DEC: +41.966d {+41d 57' 58"} (J2000),
+41.864d {+41d 51' 51"} (current),
+42.233d {+42d 13' 59"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 4526 [cnts] Image_Peak=132 [image_cnts]
TRIGGER_DUR: 2.048 [sec]
TRIGGER_INDEX: 473 E_range: 25-100 keV
BKG_INTEN: 45997 [cnts]
BKG_TIME: 60849.59 SOD {16:54:09.59} UT
BKG_DUR: 24 [sec]
GRB_DATE: 18525 TJD; 42 DOY; 19/02/11
GRB_TIME: 60884.73 SOD {16:54:44.73} UT
GRB_PHI: -132.25 [deg]
GRB_THETA: 42.07 [deg]
SOLN_STATUS: 0x83
RATE_SIGNIF: 9.16 [sigma]
IMAGE_SIGNIF: 6.93 [sigma]
MERIT_PARAMS: +1 +0 +0 +1 +2 -3 +0 +0 +61 +0
SUN_POSTN: 325.02d {+21h 40m 05s} -13.96d {-13d 57' 21"}
SUN_DIST: 127.39 [deg] Sun_angle= 8.5 [hr] (West of Sun)
MOON_POSTN: 37.38d {+02h 29m 30s} +9.31d {+09d 18' 50"}
MOON_DIST: 125.48 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 112.03, 74.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 174.37, 44.30 [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: Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.
COMMENTS: This trigger occurred at longitude,latitude = 92.91,-20.27 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 11 Feb 19 16:58:06 UT
NOTICE_TYPE: Swift-XRT Nack-Position
TRIGGER_NUM: 888648, Seg_Num: 0
POINT_RA: 196.655d {+13h 06m 37s} (J2000)
POINT_DEC: +41.974d {+41d 58' 26"} (J2000)
IMG_START_DATE: 18525 TJD; 42 DOY; 19/02/11
IMG_START_TIME: 61081.10 SOD {16:58:01.10} UT, 196.4 [sec] since BAT Trigger Time
COUNTS: 2 Min_needed= 20
STD_DEV: 0.00 Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER: 1 Max_iter_allowed= 4
ERROR_CODE: 1
COMMENTS: SWIFT-XRT Nack Position.
COMMENTS: No source found in the image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 11 Feb 19 16:59:26 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 888648, Seg_Num: 0
GRB_RA: 196.675d {+13h 06m 42s} (J2000),
196.893d {+13h 07m 34s} (current),
196.106d {+13h 04m 25s} (1950)
GRB_DEC: +41.966d {+41d 57' 58"} (J2000),
+41.864d {+41d 51' 51"} (current),
+42.233d {+42d 13' 59"} (1950)
GRB_DATE: 18525 TJD; 42 DOY; 19/02/11
GRB_TIME: 60884.73 SOD {16:54:44.73} UT
TRIGGER_INDEX: 473
GRB_PHI: -132.25 [deg]
GRB_THETA: 42.07 [deg]
DELTA_TIME: 6.00 [sec]
TRIGGER_DUR: 2.048 [sec]
SOLN_STATUS: 0x83
RATE_SIGNIF: 9.16 [sigma]
IMAGE_SIGNIF: 6.93 [sigma]
LC_URL: sw00888648000msb.lc
SUN_POSTN: 325.02d {+21h 40m 06s} -13.96d {-13d 57' 18"}
SUN_DIST: 127.39 [deg] Sun_angle= 8.5 [hr] (West of Sun)
MOON_POSTN: 37.41d {+02h 29m 38s} +9.33d {+09d 19' 34"}
MOON_DIST: 125.46 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 112.03, 74.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 174.37, 44.30 [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: Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.
COMMENTS: This trigger occurred at longitude,latitude = 92.91,-20.27 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Mon 11 Feb 19 17:01:57 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 888648, Seg_Num: 0
GRB_RA: 196.6591d {+13h 06m 38.18s} (J2000),
196.8764d {+13h 07m 30.34s} (current),
196.0895d {+13h 04m 21.48s} (1950)
GRB_DEC: +41.9673d {+41d 58' 02.2"} (J2000),
+41.8654d {+41d 51' 55.4"} (current),
+42.2344d {+42d 14' 03.8"} (1950)
GRB_ERROR: 3.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.00e-10 [erg/cm2/sec]
GRB_SIGNIF: 10.00 [sigma]
IMG_START_DATE: 18525 TJD; 42 DOY; 19/02/11
IMG_START_TIME: 61090.00 SOD {16:58:10.00} UT, 205.3 [sec] since BAT Trigger Time
TAM[0-3]: 100.00 100.00 100.00 100.00
AMPLIFIER: 1
WAVEFORM: 31
SUN_POSTN: 325.03d {+21h 40m 06s} -13.95d {-13d 57' 16"}
SUN_DIST: 127.40 [deg] Sun_angle= 8.5 [hr] (West of Sun)
MOON_POSTN: 37.43d {+02h 29m 43s} +9.33d {+09d 20' 00"}
MOON_DIST: 125.44 [deg]
MOON_ILLUM: 37 [%]
GAL_COORDS: 112.07, 74.84 [deg] galactic lon,lat of the burst
ECL_COORDS: 174.35, 44.29 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
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: The probability that this is a serendipitous source in the
COMMENTS: SPER window is 0.58% < P(seren) < 1.1%.
- GCN Circular #23883
F. E. Marshall (NASA/GSFC), P. A. Evans (U Leicester),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),
H. A. Krimm (NSF/USRA), K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (PSU), M. H. Siegel (PSU), A. Tohuvavohu (PSU) and
S. F. Tooke (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 16:54:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190211A (trigger=888648). Swift slewed after a short delay
to the burst.
The BAT on-board calculated location is
RA, Dec 196.675, +41.966 which is
RA(J2000) = 13h 06m 42s
Dec(J2000) = +41d 57' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 3 sec. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 16:58:01.1 UT, 196.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 196.65896, 41.96717 which is equivalent
to:
RA(J2000) = 13h 06m 38.15s
Dec(J2000) = +41d 58' 01.8"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 43 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.72 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.8
(+2.01/-1.78) x 10^21 cm^-2 (90% confidence).
UVOT data are not available at this time.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov).
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: /too.html.)
- GCN Circular #23884
D. Xu, B.Y. Yu (NAOC), J.H. Liu (XAO), Z.P. Zhu, B.J. Xi (NAOC), X. Gao
(Urumqi No.1 Senior High School) report on behalf of a larger collaboration:
We observed the field of GRB 190211A (Marshall et al., GCN 23883) using
the robotic NEXT-0.6m telescope located at Nanshan, Xinjiang, China.
Observations started at 16:56:38 UT on 2019-02-11, i.e., 114 s after the
BAT trigger. A series of 40 s, 60 s, 90 s, and 300 s R-band exposures
were obtained and observations are ongoing.
An uncatalogued and fading optical source is detected at coordinates
R.A. (J2000) = 13:06:38.47
Dec. (J2000) = +41:58:04.93
with an error of the radius ~ 0.3 arcsec, being consistent with the XRT
position (Marshall et al., GCN 23883). The source has m(R)~17.8 mag from
our first 40s exposure. We thus conclude this source is the optical
afterglow of the burst.
- GCN Circular #23885
V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),
O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova (Applied Physics Institute, Irkutsk State University),
V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE)
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L)
located in Russia (Blagoveshchensk State Pedagogical University)
was pointed to the GRB190211A (Marshall et al. GCN 23883)
8 sec after notice time (46 sec after trigger time) at 2019-02-11 16:55:30 UT.
On our first (10s exposure) set there is no optical transient within SWIFT
error-box (ra=196.675 dec=41.9658 r=0.05) with 16.4m (5-sigma) upper limit
(NEXT-0.6, Xu et al. GCN 23884 with RA,Dec=13:06:38.47 +41:58:04.93).
The galactic latitude b = 75 deg., longitude l = 110 deg.
The observations started when error box altitude was 65 deg.
The moon (38 % bright part) altitude was -14 deg.
The sun altitude was -50.9 deg.
MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University)
was pointed to the GRB190211A 38 sec after notice time (76 sec after triggertime)
at 2019-02-11 16:56:00 UT.
On our first (10s exposure) set we didn't find optical transient within SWIFT
error-box with 5-sigma upper limit 16.4m
The observations started when error-box altitde was 50 deg.
The sun altitude was -51.9 deg.
The message may be cited.
- GCN Circular #23886
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 (Univ. of Nikolaev) 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 190211A by Swift/BAT (Marshall et al.
GCNC 23883), the 0.6m BOOTES-4/MET robotic telescope at Lijiang
Astronomical Observatory (China) obtained follow-up observations
starting at 17:10 UT (~0.26 hr after trigger). The optical afterglow is
detected within the Swift/XRT error box with a preliminary magnitude of
19.1 mag (clear filter), thus confirming the fading in brightness of the
optical source earlier reported by Xu et al. (GCNC 23884). Observations
are ongoing."
- GCN Circular #23887
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 190211A (trigger #888648)
(Marshall, et al., GCN Circ. 23883). The BAT ground-calculated position is
RA, Dec = 196.652, 41.976 deg which is
RA(J2000) = 13h 06m 36.5s
Dec(J2000) = +41d 58' 32.1"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.
The mask-weighted light curve shows a a pair of peaks, the first from T-12 to T-5 sec,
and the second from T-4 to T+2 sec. T90 (15-350 keV) is 12.48 +- 1.46 sec (estimated
error including systematics).
The time-averaged spectrum from T-11.49 to T+1.66 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.51 +- 0.33. The fluence in the 15-150 keV band is 6.5 +- 1.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.56 sec in the 15-150 keV band
is 1.9 +- 0.4 ph/cm2/sec. 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/888648/BA/
- GCN Circular #23888
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows
(PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), K.L. Page (U.
Leicester) and F.E. Marshall report on behalf of the Swift-XRT team:
We have analysed 9.4 ks of XRT data for GRB 190211A (Marshall et al.
GCN Circ. 23883), from 205 s to 24.2 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The refined XRT
position is RA, Dec = 196.6588, +41.9671 which is equivalent to:
RA (J2000): 13 06 38.10
Dec(J2000): +41 58 01.5
with an uncertainty of 3.5 arcsec (radius, 90% confidence).
The light curve can be modelled with an initial power-law decay with an
index of alpha=0.15 (+0.16, -0.21), followed by a break at T+1088 s to
an alpha of 1.11 (+0.05, -0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+0.11, -0.10). The
best-fitting absorption column is 7.1 (+2.6, -2.4) x 10^20 cm^-2, in
excess of the Galactic value of 1.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.4 x 10^-11 (3.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.1 (+2.6, -2.4) x 10^20 cm^-2
Galactic foreground: 1.7 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index: 1.94 (+0.11, -0.10)
If the light curve continues to decay with a power-law decay index of
1.11, the count rate at T+24 hours will be 9.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.2 x
10^-13 (3.7 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00888648.
This circular is an official product of the Swift-XRT team.
- GCN Circular #23890
K.E. Heintz (Univ. of Iceland), D. Xu (NAOC), D.B. Malesani (DAWN/NBI
and DARK/NBI), S. Moran (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 190211A (Marshall et al., GCN 23883) using
the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC
camera. We obtained 3x200 s SDSS r-band and 3x300 s SDSS z-band frames,
starting at 02:23:58 UT on 2019-02-12, i.e., 9.487 hr after the BAT trigger.
The previously reported optical afterglow (e.g., Xu et al., GCN 23884;
Hu et al., GCN 23886) is clearly detected in our stacked images. The
afterglow faded to m(r)=22.7 ¡À 0.1 mag at 9.578 hr post-burst and m(z) =
22.0 ¡À 0.2 mag at 9.815 hr post-burst, calibrated with nearby SDSS stars.
- GCN Circular #23891
M. Oeda, R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, M. Niwano, R. Adachi, Y. Yatsu,
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration
We searched for the optical counterpart of GRB 190211A (F. E. Marshall et
al., GCN
Circular #23883) 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 16:55:48.41 UT which corresponds to
64 sec after the trigger.
We detected the point source at the position consistent with the robotic
NEXT-0.6m telescope
observation (D. Xu et al., GCN Circular #23884).
The measured magnitudes are listed as follows.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~64 16:56:48.41 120 ~18.3 ~17.7 ~17.0
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the Vega system.
- GCN Circular #23893
Gregory S.H. Paek, Myungshin Im (CEOU/SNU), Taewoo Kim, and Wonseok Kang
(DOAO) on behalf of a larger collaboration
We observed the afterglow of GRB 190211A(Marshall et al., GCN 23883; Xu et
al., GCN 23884; Lipunov et al., GCN 23885; Hu et al., GCN 23886; Stamatikos
et al., GCN 23887; Evans et al., GCN 23888) with the 1.0-m telescope at the
Deokheung Optical Astronomy Observatory.
The observation started at 2019-02-11 18:28 UT or about 1.5 hours after the
initial alert.
The afterglow is detected in R bands, and preliminary magnitudes are
derived, using nearby Pan-STARRS stars as photometry references.
Filter Date UT-start exptime[sec] AB_mag
R 2019-02-11 18:28:45 300*3 21.27 +/- 0.2
- GCN Circular #23894
F. E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190211A
203 s after the BAT trigger (Marshall et al., GCN Circ. 23883).
A source consistent with the optical position
(Xu et al. GCN Circ. 23884) and just outside the
90% confidence XRT position (Evans et al. GCN Circ. 23888)
is detected in the only UVOT exposure.
The preliminary UVOT position is:
RA (J2000) = 13:06:38.45 = 196.66019 (deg.)
Dec (J2000) = +41:58:04.9 = 41.96803 (deg.)
with an estimated uncertainty of 0.53 arc sec. (radius, 90% confidence).
The preliminary detection using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures is:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 203 351 146 19.73 +/- 0.11
The magnitude in the table is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
- GCN Circular #23895
B. Stecklum, S. Klose, and U. Laux report:
We observed the field of GRB 190211A (Marshall et al., GCN 23883) with the
Tautenburg Schmidt telescope equipped with the Taukam 6k x 6k CCD camera.
Observations were performed under modest seeing conditions 3.5 hr after
the burst.
In a 5-min exposure we detect the GRB afterglow (Xu et al., GCN 23884; Hu
et al., GCN 23886; Heintz et al., GCN 23890; Oeda et al., GCN 23891; Peak
et al., GCN 23893; Marshall et al., GCN 23894) with V=20.75 +/- 0.10 (Vega
mag), calibrated against the nearby star NOMAD1 1319-0272410 which has
V=14.89.
- GCN Circular #23896
Harsh Kumar (IITB), Viraj karambelkar (IITB), Gaurav Waratkar(IITB), Shubham
Srivastav (IITB), Tsewang Stanzin (IAO, IIAP), Varun Bhalerao (IITB), G.C.
Anupama (IIAP) report on behalf of the GROWTH-India collaboration:
We observed the optical afterglow of GRB190211 (Marshall et al., GCN 23883; Xu
et al. GCN 23884; Hu et al., GCN 23886; Stamatikos et al., GCN 23887; Evans et
al., GCN 23888; K.E. Heintz et al., GCN 23890; M. Oeda et al.,GCN 23891;
Gregory S.H.P. et al., GCN 23893) with the 0.7m robotic GROWTH-India telescope
at the Indian Astronomical Observatory. We obtained 600 s exposures in two
bands, starting at UT 2019-02-11 18:16:55.961 for r filter and at UT 2019-02-11
18:28:07.536 in i filter. The afterglow is clearly detected in both images.
Magnitudes were calibrated using PanSTARRs reference stars in the same field.
The measured magnitude in r filter image is 21.37+/- 0.2 and in i filter is
20.28+/- 0.3.
Based on our data combined with other r band measurements (Xu et al. GCN 23884;
Hu et al., GCN 23886; M. Oeda et al.,GCN 23891; Heintz et al., GCN 23890), we
see that the source flux is fading approximately as a power law t^-alpha, with
alpha = 0.69 +/- 0.08.
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).
Previous IAU Circulars 