GRB 190530A
GCN Circular 24978
Subject
GRB 190530A: Observation of the afterglow by NOEMA
Date
2019-07-04T15:22:54Z (6 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Bremer (IRAM),
S. Schulze (Weizmann), C. C. Thoene, D. A. Kann, L. Izzo, M. Blazek,
K. Bensch (all HETH/IAA-CSIC), D. A. Perley (LJMU), S. Martin (ALMA),
I. de Gregorio-Monsalvo (ESO), M. Michalowski (AOI-AMU),
R. Sanchez-Ramirez (INAF-IAPS), D. B. Malesani (DTU Space) report:
We observed the field of the bright GRB 190530A (Fermi team GCN
24676) with NOEMA, at wavelengths between 76 and 150 GHz in 4
epochs, ranging between 31 May 2019, at 14:29 UT (1.17 days after the
burst) and 15 June 2019, at 20:54 UT (16.44 days after the burst). The
afterglow (discovered in the optical by Lipunov et al. GCN 24680) was
detected on the first epoch with a flux density of 1.0 mJy at 92 GHz. At
this time the peak frequency was located close to this observed frequency.
In the subsequent epochs the peak frequency of the synchrotron spectrum
was bluewards of the 76 GHz frequency band and the source declined
steadily in flux density until it was no longer detected in our latest
observation, which had an r.m.s of 0.066 mJy at the 92 GHz band.
GCN Circular 24763
Subject
GRB 190530A: Further OAJ/OSN photometry and analysis
Date
2019-06-06T16:58:21Z (6 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), L. Izzo, M. Blazek, C. C. Thoene, K. Bensch (all
HETH/IAA-CSIC) report:
We checked the magnitude of our second-epoch OSN observation (Kann et
al., GCN 24700) of the Fermi GBM/LAT GRB 190530A (Fermi GBM team, GCN
24676; Longo et al., GCN 24679) and found a calculation error which
resulted in an incorrect zero-point. Remeasuring the magnitude against
four SDSS stars (once again transformed to Rc via the equations of
Lupton 2005) we now derive Rc(AB) = 19.51 +/- 0.04 mag. This is in good
agreement with the value obtained by Moskvitin & Uklein (GCN 24708). The
magnitude of Belkin et al. (GCN 24698) is still overly bright compared
to our new result, and the revised value from Vinko et al. (GCN 24751)
is now significantly fainter.
We obtained 7 x 300 s images in SDSS r' with the 0.8m telescope of the
Observatorio Astrofisico de Javalambre (Teruel, Spain). The first three
images were taken too early in twilight and were discarded. The
afterglow is clearly detected in the stack of the four last images, and
we measure:
r'(AB) = 20.27 +/- 0.06 mag at 2.43735 days after the GRB.
This is in good agreement with an earlier value from Vinko et al. (GCN
24751) combined with a steep decay.
Using the further photometry published since Kann et al. (GCN 24700)
(Moskvitin et al., GCN 24708; Belkin et al., GCN 24712; Kumar et al.,
GCN 24729; Nandi et al., GCN 24745; Vinko et al., GCN 24751) we find:
- The steep decay between the observation of Watson et al. (GCN 24690)
and Xin et al. (GCN 24697) remains, and is not significantly affected by
our revised OSN measurement.
- There may be a small flare at 1.4 days (this GCN [OSN]; Moskvitin et
al., GCN 24708).
- Starting at 2.2 days (Belkin et al., GCN 24712; Vinko et al., GCN
24751; this GCN [OAJ]; Nandi et al., GCN 24745; Kumar et al., GCN
24729), yet another steep decay sets in, for which we measure alpha =
3.72 +/- 0.43. This value is perfectly in agreement with the one derived
in Kann et al. (GCN 24700) at an earlier time, but now based on
significantly more measurements.
Further follow-up is warranted, if possible.
GCN Circular 24751
Subject
GRB 190530A: optical follow-up observations at Konkoly
Date
2019-06-05T13:27:40Z (6 years ago)
From
Jozsef Vinko at Konkoly Observatory <vinko@konkoly.hu>
J. Vinko, R. Szakats, A. Pal, L. Kriskovics, A. Ordasi, K. Sarneczky
(MTA CSFK Konkoly Observatory) report:
We took follow-up observations on the optical afterglow (Lipunov et al., GCN 24680;
Kann et al., GCN 24684; Heintz et al., GCN 24686; Izzo et al., GCN 24687;
Xin et al., GCN 24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693;
Xin et al., GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700;
Siegel, GCN 24703; Moskvitin and Uklein, GCN 24708; Vinko et al., GCN 24709;
Belkin et al., GCN 24712; Kumar et al., GCN 24729; Nandi et al., GCN 24745)
of the bright GRB 190530A (Fermi GBM team, GCN 24676, Biltzinger et al., GCN 24677;
Longo et al., GCN 24679; Lucarelli et al.,GCN 24678, Verecchia et al., GCN 24683).
The source was clearly detected on the stacked Sloan-r band CCD frames (total exposure time 60 min)
taken with the 0.8m RC80 telescope at Konkoly Observatory, Piszkesteto (Hungary)
on 2019-06-01.85 UT, but only marginally detected on the frames taken
on 2019-06-02.86 UT (2.42 and 3.43 days after burst, respectively).
We measured the brightness of the transient via aperture photometry on the stacked
r-band frames using PS1 r-band magnitudes of 19 local comparison stars. The results,
corrected for the contamination of the nearby faint source (r_PS1(AB) = 20.947 +/- 0.0565 mag),
are as follows:
# Date UT(mid) JD-2400000 r(AB) unc. Ref
#----------------------------------------------------------------
2019-05-31 20:23:35 58635.349711 20.36 0.37 GCN 24709
2019-06-01 20:23:56 58636.349953 20.15 0.11 this circular
2019-06-02 20:37:30 58637.359375 22.10 0.41 this circular
#----------------------------------------------------------------
Note that in Vinko et al. (GCN 24709) the UT date of the observation was
reported incorrectly. The correct date was 2019-05-31.85 UT. Also, our
previous photometry given in GCN 24709 was not corrected for the nearby
contaminating source. The table above contains the updated, corrected
magnitudes.
Our last photometric measurement (taken on 2019-06-02) is consistent with the
R-band magnitude reported by Kumar et al. (GCN 24729, R ~ 21.3 +/- 0.3 mag).
GCN Circular 24745
Subject
GRB190530A: Photometric follow-up with GROWTH-India telescope
Date
2019-06-04T18:04:50Z (6 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
D. Nandi, Abhinand V, H. Kumar, M. Khandagale, V. Bhalerao(IITB), G. C.
Anupama, J. Stanzin (IIA) report on behalf of the GROWTH collaboration:
We observed the field of GRB190530A reported by Fermi GBM Team (GCN 24676)
at 2019-06-01.635 and 2019-06-02.685 UT with the 0.7m GROWTH-India
telescope. The images were taken in r filter. We detect a very faint source
at position Ra: 08h 02m 07.73s, Dec: +35d 28m 47.7s. Photometric results
obtained are as follow:-
------------------------------------------------------------------
MJD(Start)| Exposure(s) | Stacked | Filter | Mag | Magerr |
------------------------------------------------------------------
58635.636 | 600 | No | r | 20.118 | 0.14 |
58636.685 | 5*500 | YES | r | 20.48 | 0.11 |
------------------------------------------------------------------
Magnitudes are calibrated with panstarrs in the same field. Photometric
results are found to be in agreement with (Lipunov et al., GCN 24680; Kann
et al., GCN 24684; Heintz et al., GCN 24686; Izzo et al., GCN 24687; Xin et
al., GCN 24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693; Xin et
al., GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700;Vinko et
al., GCN 24709; Siegel, GCN 24703; Moskvitin and Uklein, GCN 24708; Belkin
et al., GCN 24712; Brajesh et al., GCN 24729). Using data of
above-mentioned GCNs along with GIT data, we found that source is fading
with a power law index of 1.52.
The fitted curve can be found here:
https://lh5.googleusercontent.com/uyI9IhOx5bbe7_Ii-eHWsaj7r2Qw1g10_Lb_HIWKd5YBp8xsYC1OCPhdvYGifF80tkEgfWI-SMZl5RqgyRisuJS4mt3tHAIBEwoyVRJwX3B2LtsjVx1V=w572
The GROWTH India Telescope (GIT) 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 24729
Subject
GRB 190530A: R-band observation from HCT
Date
2019-06-03T13:53:56Z (6 years ago)
From
Brajesh Kumar at Indian Inst. of Astrophysics <brajesh.kumar@iiap.res.in>
Brajesh Kumar (IIA), Avinash Singh (IIA), G. C. Anupama (IIA), D. K.
Sahu (IIA) and S. B. Pandey (ARIES)
We observed the field of GRB 190530A (Fermi GBM team, GCN 24676,
Biltzinger et al., GCN 24677; Lucarelli et al.,GCN 24678, Longo et al.,
GCN 24679; Verecchia et al., GCN 24683) with the 2-m Himalayan Chandra
Telescope (HCT) located at the Indian Astronomical Observatory, Hanle,
India. The observations started on 2019-06-02 14:50:43 UT i.e. around
3.19 days from Fermi GBM trigger (GCN 24676).
The optical afterglow (Lipunov et al., GCN 24680; Kann et al., GCN
24684; Heintz et al., GCN 24686; Izzo et al., GCN 24687; Xin et al., GCN
24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693; Xin et al.,
GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700; Siegel, GCN
24703; Moskvitin and Uklein, GCN 24708; Vinko et al., GCN 24709; Belkin
et al., GCN 24712) is detectable in our stacked image taken in Bessell
R-band with a total integration time of 15 min. The preliminary
magnitude of the OT is estimated as 21.3 +/- 0.3 mag.
These magnitudes were calibrated using the field stars from the
USNO-B1.0 catalogue.
We thank the observing staff at IAO and CREST for helping with the
observations.
GCN Circular 24715
Subject
Konus-Wind observation of extremely bright GRB 190530A
Date
2019-06-02T15:18:51Z (6 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The extremely bright, long GRB 190530A
(Fermi GBM detection: GCN 24676,24692; AGILE-MCAL detection: GCN 24679;
Fermi-LAT detection: GCN 24679; AGILE/GRID analysis: GCN 24683;
AstroSat CZTI detection: GCN 24694) triggered Konus-Wind (KW)
at T0=37146.000 s UT (10:19:06.000).
The light curve of the burst shows a bright, multi-peaked pulse
with a total duration of ~55s, followed by a weaker and softer
emission tail visible until ~T0+150 s.
The emission in the bright phase of the burst is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/
As observed by Konus-Wind, the burst had
a fluence of (5.57 �� 0.15)x10^-4 erg/cm2 and
a 64-ms peak energy flux, measured from T0+14.912,
of (1.59 �� 0.10)x10^-4 erg/cm2 (both in the 20 keV - 10 MeV
energy range).
The time-integrated spectrum (measured from T0 to T0+44.228 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.03 (-0.02,+0.02),
the high energy photon index beta = -3.03 (-0.36,+0.22),
the peak energy Ep = 848 (-33,+44) keV,
chi2 = 140/96 dof.
The spectrum near the peak count rate (measured from T0+14.848 s
to T0+15.104 s) is best fit in the 20 keV - 16 MeV range
by a cutoff power-law (CPL) function with the following model
parameters: the photon index alpha = -0.41(-0.07,+0.07),
and the peak energy Ep = 1176(-46,+47) keV, chi2 = 55/60 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta of -3.2.
Assuming an upper limit on the burst redshift z<2.2 (Heintz et al.,
GCN 24686) and a standard cosmology with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70, we estimate the following
upper limits on the GRB rest-frame energetics: the isotropic energy
release E_iso < 6.4x10^54 erg and the peak luminosity L_iso < 5.8x10^54
erg/s (both in the bolometric 1-10000 keV range).
Location of GRB 190530A in rest-frame hardness-intensity planes,
along with 'Amati' and 'Yonetoku' relations for the KW sample of
GRBs with known redshifts (Tsvetkova et al., ApJ 850 161, 2017), can be
found at http://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/GRB190530A.pdf
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 24714
Subject
GRB 190530A: Insight-HXMT/HE detection
Date
2019-06-02T15:17:47Z (6 years ago)
From
QiBin Yi at IHEP, HXMT <yiqb@ihep.ac.cn>
Q. B. Yi, S. Xiao, Q. Luo, C. Cai, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
At 2019-05-30T10:19:08.90 (T0), Insight-HXMT/HE detected
GRB 190530A (trigger ID: HEB190530429) in a routine search of the data,
which was also triggered by Fermi/GBM (GCN #24676), Fermi/LAT
(GCN #24679), and AGILE/MCAL(GCN #24678).
The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 20.31 s measured from T0+2.11 s.
The 1-ms peak rate, measured from T0+10.52 s, is 18182 cnts/sec.
The total counts from this burst is 214189 counts.
Some part of the Insight-HXMT/HE light curve suffers data saturation
due to the extreme brightness of this burst.
URL_LC: http://www.hxmt.org/images/GRB/HEB190530429_lc.jpg
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was
funded jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.
GCN Circular 24712
Subject
GRB 190530A: Mondy and AbAO optical observations
Date
2019-06-02T09:53:20Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), A.
Pozanenko (IKI), V.R. Ayvazian (AbAO), E. Mazaeva (IKI), A. Volnova
(IKI) report on behalf of IKI GRB FuN collaboration:
We continue observations the optical afterglow (Lipunov et al., GCN
24680, 24693 and also e.g. Kann et al., GCN 24684; Melandri et al., GCN
24689; Heintz et al., GCN 24686; Lzzo et al., GCN 24687; Xin et al.,
GCN 24688; Watson et al., GCN 24690; Xin et al., GCN 24697) of the
Fermi GRB 190530A (Fermi GBM Team, GCN 24676; Longo et al., GCN
24679) with AZT-33IK telescope of Sayan observatory (Mondy) and AS-32
(0.7m) telescope of Abastumani Observatory. The afterglow is clearly
visible in stacked images. Preliminary photometry of the afterglow is
following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2019-06-01 15:35:00 2.23638 R 29*60 19.62 0.07 21.2
2019-06-01 17:38:57 2.31769 R 30*60 19.70 0.14 20.6
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0_id R2
1255-0157926 13.35
1254-0159410 12.63
1255-0157793 13.56
The photometry might be influenced by nearby optical source presented in
Pan-STARRS DR1 catalog (ID 150571205309266249) mentioned in (Lipunov
et al., GCN 24680).
GCN Circular 24709
Subject
GRB 190530A: Konkoly optical observations of the afterglow
Date
2019-06-01T18:26:08Z (6 years ago)
From
Jozsef Vinko at Konkoly Observatory <vinko@konkoly.hu>
J. Vinko, R. Szakats, A. Pal, L. Kriskovics, A. Ordasi, K. Sarneczky
(MTA CSFK Konkoly Observatory) report:
The optical afterglow (Lipunov et al., GCN 24680; Kann et al., GCN 24684; Heintz et al., GCN 24686;
Izzo et al., GCN 24687; Xin et al., GCN 24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693;
Xin et al., GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700; Siegel, GCN 24703;
Moskvitin and Uklein, GCN 24708) of the bright GRB 190530A (Fermi GBM team, GCN 24676, Biltzinger et al.,
GCN 24677; Longo et al., GCN 24679; Lucarelli et al.,GCN 24678, Verecchia et al., GCN 24683)
is marginally detected on the stacked Sloan-r band CCD frames (total exposure time 45 min)
taken with the 0.8m RC80 telescope at Konkoly Observatory, Piszkesteto (Hungary)
on 2019-05-31.35 UT, 1.42 day after the burst.
Aperture photometry on the stacked frame, tied to PS1 r-band data of 19 local comparison
stars resulted in the following AB magnitude for the transient:
r_PS1 (AB) = 19.86 +/- 0.37 mag
This is consistent with R-band brightness (~19.39 +/- 0.05 AB-mag at 1.353 days after burst) reported by
Moskvitin and Uklein (GCN 24708), but significantly brighter than the one measured by Kann
et al. (GCN 24700, Rc ~ 20.60 +/- 0.15 AB-mag at 1.44509 day after burst).
Further monitoring of this interesting transient is encouraged.
GCN Circular 24708
Subject
GRB 190530A: SAO RAS optical observations
Date
2019-06-01T12:21:26Z (6 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
Moskvitin A. S. and Uklein R. I. (SAO RAS)
report on behalf of larger collaboration.
We observed the field of the GRB 190530A (Fermi GBM Team, GCNC 24676;
Longo et al., GCNC 24679) with the 1-m telescope of SAO RAS
equipped with the MMPP (Multi-Mode Photometer-Polarimeter)
and UBVRcIc filters on May 31 / June 1 night.
We obtained 11 x 300 sec. frames in Rc band.
The OT (Lipunov et al., GCNC 24680; Kann et al., GCNC 24684;
Heintz et al., GCNC 24686; Izzo et al., GCNC 24687;
Xin et al., GCNC 24688; Watson et al., GCNC 24690;
Lipunov et al., GCNC 24693; Xin et al., GCNC 24697;
Belkin et al., GCNC 24698; Kann et al., GCNC 24700;
Siegel, GCNC 24703) is clearly detected in our stacked image.
The OT brightness is R(AB) = 19.39 +/- 0.05 (T_mid - T0 = 1.353 days).
The OT magnitude was calculated against the nearby SDSS stars
whose magnitudes were transformed with the equations of Lupton (2005).
The magnitude of OT was converted to AB system
and was not corrected for the Galactic extinction.
GCN Circular 24703
Subject
GRB 190530A: Swift/UVOT Detection
Date
2019-06-01T03:10:41Z (6 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190530A
33.8 ks after the LAT trigger (GCN Circ. 24676). A fading source consistent
with the optical counterpart first reported by Lipunov et al. (GCN Circ.
24680) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 08:02:07.70 = 120.53209 (deg.)
Dec (J2000) = +35:28:46.8 = 35.47968 (deg.)
with an estimated uncertainty of 0.49 arc sec. (radius, 90% confidence).
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
v 56532 56734 199 18.49 +/- 0.23
b 38334 38490 153 18.06 +/- 0.09
u 38132 38329 194 17.09 +/- 0.06
w1 37734 38128 388 16.89 +/- 0.06
w2 44276 44610 329 17.39 +/- 0.08
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 24700
Subject
GRB 190530A: Steep afterglow decay found by OSN
Date
2019-05-31T23:13:05Z (6 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann, L. Izzo (both HETH/IAA-CSIC), A. de Ugarte Postigo
(HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. C. Thoene, K. Bensch (all
HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:
We observed the afterglow position (Lipunov et al., GCN 24680) of the
extremely bright GRB 190530A (GBM detection and localization: Fermi GBM
team, GCN 24676, Biltzinger et al., GCN 24677; Fermi-LAT localization:
Longo et al., GCN 24679; Agile-MCAL/GRID detections: Lucarelli et al.,
GCN 24678, Verecchia et al., GCN 24683) a second time with the 1.5-m
telescope of the Sierra Nevada Observatory (OSN), Spain. The afterglow
is now only marginally detected in single frames, so we stack 7 x 120 s
images.
We measure the following AB magnitude:
Rc = 20.60 +- 0.15 mag at 1.44509 days after the GRB.
The magnitude was derived against 1 nearby star from the SDSS catalog,
using the transformation equations of Lupton (2005), and transformed
back into AB mag.
This magnitude is significantly fainter than expected from an
extrapolation of the decay from the first day, indicating a break in the
light curve must have occurred. Using other observations (Lipunov et
al., GCN 24680, GCN 24693; Kann et al., GCN 24684; Heintz et al., GCN
24686; Izzo et al., GCN 24687; Xin et al., GCN 24688; Watson et al., GCN
24690; Xin et al., GCN 24697) we find the afterglow is described by a
broken power-law with pre-break decay slope alpha_1 = 1.21 +/- 0.07,
post-break decay slope alpha_2 = 3.75 +/- 0.40, and break time t_b =
0.78 +/- 0.06 days.
The steeper slope mentioned by Watson et al. (GCN 24690) may indicate
the break was occurring during the COATLI observations. We note the
magnitude given by Belkin et al. (GCN 2469 is significantly too bright,
this may stem from their use of USNO stars as standard stars.
The post-break decay slope is extremely steep and generally not expected
from the forward shock model and a typical electron energy distribution.
Further observations are highly encouraged.
GCN Circular 24698
Subject
GRB 190530A: AbAO optical observations
Date
2019-05-31T21:55:33Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V.R.
Ayvazian (AbAO), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf
of larger IKI GRB FuN collaboration:
We observed the optical afterglow (Lipunov et al., GCN 24680, 24693;
Kann et al., GCN 24684; Melandri et al., GCN 24689; Heintz et al., GCN
24686; Lzzo et al., GCN 24687; Xin et al., GCN 24688; Watson et al.,
GCN 24690; Xin et al., GCN 24697) of the Fermi GBM, LAT GRB 190530A
(Fermi GBM Team, GCN 24676; Longo et al., GCN 24679) with AS-32
(0.7m) telescope of Abastumani Observatory starting on May 31 (UT)
17:44:00. Preliminary photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2019-05-31 17:44:00 1.32171 R 19*60 18.5 0.1 19.5
The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1255-0157926 13.35
1254-0159410 12.63
1255-0157793 13.56
GCN Circular 24697
Subject
GRB 190530A: Xinglong 2.16m optical observation
Date
2019-05-31T21:29:02Z (6 years ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
L. P. Xin, J. B. Zhang, G. W. Li, R. S. Zhang, T. C. Zheng, J. Wang,
J. Y. Wei, Y. G. Yang, E. W. Liang, X. G. Wang, H. L. Li, X. H. Han,
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,
W. L. Dong, P. P. Zhang and Jirong Mao report:
We observed Fermi GRB 190530A (Fermi GBM Team, GCN Circ. 24676;
Longo et al., GCN Circ. 24679) using the Xinglong-2.16m equipped with
the BFOSC camera. Observations were carried out from 12:49:45 to
13:40:10 UT on 2019-05-31, 62*50sec R band images were obtained.
The optical afterglow (Lipunov et al., GCN 24680, 24693; Kann et al., GCN Circ 24684;
Melandri et al., GCN Circ. 24689; Heintz et al., GCN Circ 24686