The outermost cluster of M 31
Università di Bologna, Dipartimento di Astronomia, via Ranzani 1, 40127 Bologna, Italy e-mail: email@example.com
2 INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [michele.bellazzini;luciana.federici;flavio.fusipecci]@bo.astro.it
Accepted: 1 March 2005
We report on the identification of a new cluster in the far halo of the M 31 galaxy. The cluster, named Bologna 514 (B514) has an integrated magnitude , and a radial velocity, as estimated from two independent low-resolution spectra, km s-1, which fully confirms its membership to the M 31 system. The observed integrated spectrum is very similar to those of classical globular clusters. Being located at ( kpc in projected distance) from the center of the parent galaxy, B514 is by far the most remote M 31 cluster ever discovered. Its projected position, near the galaxy major axis, and M 31-centric velocity, similar to that observed in the outermost regions of the HI rotation curve, may indicate that it belongs to the subsystem of M 31 clusters that has been recently proposed (Morrison et al. 2004 ) to be part of the dynamically-cold thin disc of the galaxy.
Key words: galaxies: Local Group / galaxies: star clusters / galaxies: kinematics and dynamics / galaxies: spiral
© ESO, 2005