TITLE:   GCN CIRCULAR
NUMBER:  10606
SUBJECT: GRB 100414A: Gemini-N candidate and redshift
DATE:    10/04/17 08:16:49 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara and D. B. Fox  (PSU) report on behalf of
a larger collaboration:

"Starting on 2010 April 17.26 UT we used the GMOS spectrograph
on the Gemini North 8-m telescope to observe the field of the
Fermi-LAT GRB 100414A (Takahashi et al. GCN 10594).

In our 5 min i'-band observation we detected a bright source
inside the refined XRT error circle (Page et al., GCN 10605)
at the following coordinate:

RA: 12:48:29.96
Dec: +8:41:34.91

with 0.5" uncertainty in both directions.

Using two USNO-B1 stars we obtain i' = 20.37 +- 0.03 mag for this
object.
A sequence of 2x1200s spectra were also obtained with the same
instrument, covering a spectral range of 4000-8000A.

A series of metal absorption features were identified (FeII2374,
FeII2383,FeII2587,MnII2594, FeII2600, MgII2796,2803,MgI2853) at
the common redshift of z= 1.368.

We therefore suggest this as the redshift of GRB 100414A.
Further observations are planned.

We thank the Gemini staff for performing this observation,
in particular A. Fritz."