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