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Discovery of a Nova in the M31 Globular Cluster Bol 111

ATel #1118; R. Quimby, P. Mondol, J. Craig Wheeler (University of Texas), E. Rykoff, F. Yuan, C. Akerlof (University of Michigan), A. Shafter (SDSU), E. Ofek and M. Kasliwal (Caltech)
on 22 Jun 2007; 23:46 UT
Credential Certification: Robert Quimby (quimby@astro.as.utexas.edu)

Subjects: Optical, Cataclysmic Variable, Globular Cluster, Nova, Transient

Referred to by ATel #: 1294, 1647, 1671

We report the discovery of a nova coincident with the cataloged globular cluster Bol 111 in M31. The object was discovered in unfiltered images taken around June 19.4 UT (about 16.8 mag) and June 21.4 (about 16.9 mag) by the 0.45m ROTSE-IIIb telescope at the McDonald Observatory. The nova is located at RA = 00h42m33.14s DEC = 41o00'25.9" (J2000; +/- 0.3" in each coordinate), which is 2' 6.0" west and 15' 42.6" south of the core of M31, and consistent to within the errors of the location of Bol 111.

Photometry from the Palomar 60" telescope indicate the source (including light from the globular cluster) faded in the i-band by 0.24 mag between June 21.374 and June 22.469 UT.

A spectrum (420-890 nm) obtained on June 22.44 UT with the 9.2m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by M. Shetrone and V. Riley shows the object is a nova. Broad emission features including H-alpha (HWZI ~3100 km/s), H-beta, and H-gamma are detected, and the presence of N III 4640 blended with He II 4686 suggests membership in the He/N class of novae. He/N novae are relatively rare and make up only about 15% of the novae with measured spectra in M31. The lines are blueshifted by ~400 km/s, consistent with the lineshift observed for Bol 111 (Galleti et al. 2006).

We note that there have been only two other classical novae firmly associated with globular clusters (e.g. Shara et al. 2004).

A finding chart can be found at: http://grad40.as.utexas.edu/~quimby/tss/charts/nova13.png