[AAVSO-HEN] GRB 090401B: NOT optical observations

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  9078
SUBJECT: GRB 090401B: NOT optical observations
DATE:    09/04/01 22:10:33 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at astro.ku.dk>

D. Malesani, J.P.U. Fynbo (DARK/NBI), J. Heidt (Heidelberg), T. Liimets 
(Tartu Observatory), T. Pursimo (NOT), and P. Jakobsson (Univ. Iceland), 
report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 090401B (Schady et al., GCN 
9066; Schady & Oates, GCN 9067), also detected by AGILE (Moretti et al., 
GCN 9069; Giuliani et al., GCN 9075). Observations were carried out in 
the R band with the Nordic Optical Telescope, starting on April 1.870 
UT, 12.3 hr after the GRB.

In a single 300 s exposure, the afterglow is clearly detected, with a 
magnitude R ~ 22.2 +- 0.1, referred to USNO-B1 stars in the neighbourhood.

We acknowledge excellent support from the NOT visiting observers and staff.