The lack of objects between 2M⊙ and 5M⊙ in the joint
mass distribution of compact objects has been termed "mass gap", and attributed
mainly to the characteristics of the supernova mechanism precluding their
birth. However, recent observations show that a number of candidates reported
to lie inside the "gap" may fill it, suggesting instead a paucity that may be
real or largely a result of small number statistics. We quantify in this work
the individual candidates and evaluate the joint probability of a mass gap. Our
results show that an absolute mass gap is not present, to a very high
confidence level. It remains to be seen if a relative paucity of objects stands
in the future, and how this population can be related to the formation
processes, which may include neutron star mergers, collapse of a neutron star
to a black hole and others.Comment: 20 pages, 7 figures, 5 tables. Accepted for publication in Ap