The population of compact radio sources in M 17
  We present a catalog of radio sources of the M 17 region based on deep X band
radio observations centered at 10 GHz obtained with the Jansky Very Large Array
in the A configuration. We detect a total of 194 radio sources, 12 of them
extended and 182 compact. We find that a significant fraction (at least 40% in
our catalog) have suspected gyrosynchrotron emission associated with stellar
coronal emission. By comparing the radio luminosities of our sources with their
X ray counterparts, when available, we find that they are underluminous in X
rays with respect to the G\"udel Benz relation, but a correlation with a
similar slope is obtained provided that only sources with evident non thermal
nature are selected from the sample compiled for the Orion Nebula Cluster (ONC)
and M 17. The comparison of M 17 with the ONC and NGC 6334D-F leads to a
similar luminosity function for the three regions, at least for the more
luminous sources. However, the radio sources in M 17 are three times more
numerous compared to the other regions at a given luminosity and their spatial
distribution differs from that of Orion. Moreover, an arc-shaped structure of
40$"$ in extent is observed in our map, identified previously as an ionizing
front, with the cometary Hyper Compact source UC1 at its focus. Archival 1 mm
ALMA data reveals compact emission coincident with the radio wavelength peak,
possibly associated with a protostellar disk of the massive star exciting UC1.
