New Determination of Fundamental Properties of Palomar 5 Using Deep DESI
  Imaging Data
  The legacy imaging surveys for the Dark Energy Spectroscopic Instrument
project provides multiplecolor photometric data, which are about 2 mag deeper
than the SDSS. In this study, we redetermine the fundamental properties for an
old halo globular cluster of Palomar 5 based on these new imaging data,
including structure parameters, stellar population parameters, and luminosity
and mass functions. These characteristics, together with its tidal tails, are
key for dynamical studies of the cluster and constraining the mass model of the
Milky Way. By fitting the King model to the radial surface density profile of
Palomar 5, we derive the core radius of $r_c$ = 2.96' $\pm$ 0.11', tidal radius
of $r_t$ = 17.99' $\pm$ 1.49', and concentration parameter of $c$ = 0.78 $\pm$
0.04. We apply a Bayesian analysis method to derive the stellar population
properties and get an age of 11.508 $\pm$ 0.027 Gyr, metallicity of [Fe/H] =
-1.798 $\pm$ 0.014, reddening of $E(B-V)$ = 0.0552 $\pm$ 0.0005, and distance
modulus of $(m-M)_0$ = 16.835 $\pm$ 0.006. The main-sequence luminosity and
mass functions for both the cluster center, and tidal tails are investigated.
The luminosity and mass functions at different distances from the cluster
center suggest that there is obvious spatial mass segregation. Many faint
low-mass stars have been evaporated at the cluster center and the tidal tails
are enhanced by low-mass stars. Both the concentration and relaxation times
suggest that Palomar 5 is a totally relaxed system.
