TITLE:
Update to Four Estimates of the Dark Matter Warmness
AUTHORS:
Bruce Hoeneisen
KEYWORDS:
Warm Dark Matter, Spheroidal Galaxies, Dwarf Galaxies, Free Streaming, Dark Matter
JOURNAL NAME:
International Journal of Astronomy and Astrophysics,
Vol.16 No.2,
May
29,
2026
ABSTRACT: Recently it has become possible to obtain the dark matter density
ρ
h
(
r
)
of dwarf spheroidal galaxies dSph by measuring the line-of-sight velocity of individual stars. Studying 27 dSph we have arrived at the following tentative conclusions: i) dark matter is warm, ii) some dwarf spheroidal galaxies are first generation galaxies in the warm dark matter scenario, iii) rotating dwarf irregular galaxies dIrr and spiral galaxies have dark matter halos that are rotating strongly, and iv) the dark matter halo rotation of some dSph is negligible. With this new tentative information, in the present study we update four estimates of the dark matter warmness based on dSph density runs
ρ
h
(
r
)
, the mass of first generation galaxies, the distribution of galaxy masses, and from the number density of isolated dwarf galaxies in the Local Field. These four largely independent estimates are consistent with a “standard thermal relic mass”
0.6 keV≲
m
th
≲1.6 keV
, in tension with some of the current limits.