TITLE:   GCN CIRCULAR
NUMBER:  21895
SUBJECT: LIGO/Virgo G298048: TOROS photometry of SSS17a
DATE:    17/09/18 16:22:27 GMT
FROM:    Mario Diaz at U of Texas  <mario.diaz@utrgv.edu>

M. Diaz, L. Macri, J.L. Nilo Castellon, B. Sanchez, C. Mendes, C. Colazo, M. Schneitter, C. Girardini, D. Garcia Lambas, M. Beroiz, A. Zadrozny, R. Camuccio, M. Castillo. J. Garcia for the TOROS collaboration

We have completed the PSF photometry of the observations of GW170817 carried out at the T80S telescope and the EABA telescope on 08/18/2017 and 08/19/2017 (GCN 21619, GCN, 21620). We calibrated our measurements using the Pan-STARRS1 catalog available at STScI, using their reported PSF magnitudes and uncertainties. The mid-point of our observations was 1.467d after the GW trigger - LIGO/Virgo G298048- (Julian Date of 2457984.495). At that time, we measured magnitudes of g=18.60, r=17.99, i=17.80 with uncertainties of +-0.02 mag.
Additionally with our observations utilizing the EABA telescope we obtained  r=18.78+-0.03 at 2.456d after the GW trigger -LIGO/Virgo G298048-. 


_______________________________________
Mario C. D��az
Director
Center for Gravitational Wave Astronomy and
Professor
Department of Physics and Astronomy
The University of Texas Rio Grande Valley
(956) 882-6690   FAX: (956) 882-6726
mario.diaz@utrgv.edu    http://www.mariodiaz.org/
______________________________________
No ceder Carhue al huinca. Calfucura (1873)