TITLE:
Warm Dark Matter Studies with Spiral Galaxy Data
AUTHORS:
Bruce Hoeneisen
KEYWORDS:
Warm Dark Matter, Spiral Galaxies
JOURNAL NAME:
International Journal of Astronomy and Astrophysics,
Vol.15 No.4,
November
4,
2025
ABSTRACT: We measure the “warmness” of the dark matter, i.e. the comoving root-mean-square thermal velocity
v
hrms
(
1
)
, with nearly 3000 spiral galaxy rotation curves in the PROBES catalog. The results are
v
hrms
(
1
)=700±165
m/s if dark matter is collisional, or
v
hrms
(
1
)≈280±95
m/s if dark matter is collisionless. These results are in agreement with previous measurements of
v
hrms
(
1
)
, and with independent measurements of the linear density power spectrum cut-off wavevector
k
fs
due to free-streaming, but are in disagreement with limits. This disagreement is not currently understood.