TITLE: GCN CIRCULAR NUMBER: 21527 SUBJECT: LIGO/Virgo G298048: Updated sky map from gravitational-wave data DATE: 17/08/17 23:54:40 GMT FROM: Reed Clasey Essick at MIT The LIGO Scientific Collaboration and the Virgo Collaboration report: Parameter estimation has been performed using LALInference (Veitch et al., PRD 91, 042003) and a revised sky map, preliminary-LALInference.fits.gz, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/events/G298048 We caution that this is a preliminary map from the offline parameter estimation. This analysis uses data from the LIGO Hanford, LIGO Livingston, and Virgo detectors with the noise transient in Livingston removed from the data prior to the analysis, as described in GCN 21513. Posterior chains in the parameter estimation may not yet have fully converged. The 50% and 90% credible regions span about 8.6 and 33.6 square degrees, respectively, which are somewhat larger than the initial BAYESTAR sky map. The centroid (maximum a posteriori) sky location is R.A.=13h09m, Dec.=-25d37m. We will continue to refine the sky map as offline parameter estimation improves and as we apply additional methods of cleaning the data.