2011ATel.3467....1B

Using an r-band acquisition image from GMOS on the Gemini-South 8-m telescope we obtain the following refined coordinates for the likely LBV PSN J17592296+0617267 in NGC 6509 (CBET 2754) relative to the 2MASS catalog:

RA(J2000) = 17:59:22.995 DEC(J2000) = +06:17:26.56,

with an uncertainty of 0.1" in each coordinate. This position is about 0.5" away from the value listed in CBET 2754.

We further obtained archival Hubble Space Telescope WFPC2 images of NGC 6509 in the F606W filter (1800 sec; 2007 Apr 22; PI: Martini) and F814W filter (640 sec; 2000 Jul 3; PI: Boeker) to search for an associated progenitor. Using 60 common object between the HST images and our Gemini image we refined the relative astrometry to about 23 milliarcsecond in each coordinate. No source is detected at the position of the transient to a limit of about 26 AB mag (3-sigma) in both filters. At the distance of NGC 6509 (m-M = 32.25 mag) this corresponds to an absolute magnitude limit of >-6.4 mag, at least 1 mag fainter than the progenitor of UGC2773 OT2009-1 (Smith et al. 2010, Foley et al. 2011), and possibly indicative of dust obscuration. Inspection of archival Spitzer/IRAC images (540 sec; 2008 Oct 30; PI: Martini) does not reveal a coincident source at 3.6 to 8.0 microns, indicating that the progenitor is not fully dust enshrouded.