TITLE:   GCN CIRCULAR
NUMBER:  28382
SUBJECT: GRB 200906A: EMIR/GTC NIR upper limit
DATE:    20/09/07 18:26:14 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, 
C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), 
D. Reverte Paya (GTC) report:

We observed the field of GRB 200906A (Page et al., GCN #28371; 
GBM detection: Fermi GBM Team, GCN #28370; Hamburg et al., 
GCN #28374) with EMIR on the 10.4m GTC telescope, at the Roque 
de los Muchachos Observatory (La Palma, Spain). The observation 
consisted of H-band imaging with a total integration time of 955 s, and 
a mean epoch on the 6th of September at 23:57:35 UT (10.5753 hr 
after the Swift trigger).

No source is detected within the refined XRT error circle (Beardmore 
et al., GCN #28373) down to a 3-sigma limit of 

H(AB) > 23.5 mag 

This non detection is consistent with the previously reported limits 
(Fu et al., GCN#28372; Kann et al., GCN#28376; Kumar et al., 
GCN#28377; Gropp et al., GCN#28379; Rossi et al. GCN#28381)
and confirms the dark nature of the burst.