GCN Circular 25563
Subject
GRB 190829A: NOT optical afterglow detection and spectroscopy
Date
2019-08-30T03:42:22Z (5 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
K. E. Heintz (Univ. of Iceland), J. P. U. Fynbo (DAWN/NBI), P. Jakobsson
(Univ. of Iceland), D. Xu (NAOC), D. A. Perley (LJMU), D. B. Malesani
(DTU space), and J. Viuho (NOT), report on behalf of a larger
collaboration:
We observed the Swift-detected GRB 190829A (Dichiara et al., GCN 25552)
with the Nordic Optical Telescope (NOT) equipped with AlFOSC. We
obtained 3x300s r-band images at a mid-time of 02:03:52 UT on August 30
(i.e. 6.1 hr post-burst). We clearly detect the optical counterpart
reported by Xu et al. (GCN 25555), superimposed on the SDSS galaxy
J025810.28-085719.2 at z=0.08 as noted previously. We measure a
preliminary magnitude of r(AB) = 18.9 +/- 0.1 for this source,
calibrated against photometry of nearby field stars from the Pan-STARRS
catalog.
Following the imaging sequence, we obtained a series of spectra with an
integration time of 4x600s using grism 4 (covering 320-960 nm),
beginning at 02:27:42 UT. The spectrum shows a featureless red
continuum, with no clear absorption lines to identify the redshift.
Since the continuum is detected at all observed wavelengths we can place
a limit on the redshift of z < 1.8.
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