1996/09/25 by Terry Bridges, Bridges, T. J., Keith Ashman +11
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.astro-ph/9609176
openalex publication_date 1996/09/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have obtained spectra for globular cluster candidates in M104 with LDSS-2 on the William Herschel Telescope, confirming 34 objects as M104 globular clusters. We find a cluster velocity dispersion of ∼ 260 km/sec, and the Projected Mass Estimator gives a mass of 5.0 (3.5,6.7) × 1011 M_\odot for M104 within a projected radius of ∼ 330'' (14 kpc for D=8.55 Mpc). Our best estimate for the mass-to-light ratio is M/LVT= 16+5.5-5.0 within the same radius. Considering all of the possible sources of uncertainty, we find a lower limit of M/LV= 5.3, which is larger than the M/LV found from rotation curve analyses inside 180''. We thus conclude that the mass-to-light ratio increases with radius, or in other words that M104 possesses a dark matter halo. There is a marginal detection of rotation in the M104 cluster system at the 92.5% confidence level; larger samples will be needed to investigate this possibility. Interestingly, the M104 globular cluster and planetary nebulae (PNe) kinematics are roughly consistent inside ∼ 100''. Finally, we find a mean cluster metallicity of [Fe/H] = -0.70 ± 0.3, which is more typical of clusters in gE/cD galaxies than it is of clusters in other spirals.