# New mass bound on fermionic dark matter from a combined analysis of classical dSphs

## TL;DR

This study establishes a new lower mass bound for fermionic dark matter using combined data from multiple dwarf spheroidal galaxies, refining previous limits and suggesting a possible preference for 220 eV particles.

## Contribution

It provides the first combined analysis of multiple dSphs to set a more stringent lower bound on fermionic dark matter mass, improving upon previous individual galaxy studies.

## Key findings

- New 2σ lower bound of m ≥ 190 eV for fermionic dark matter.
- Possible preference for 220 eV fermionic dark matter over CDM at 2σ.
- Modeling issues with Carina dSph affect the combined analysis.

## Abstract

Dwarf spheroidal galaxies (dSphs) are the most compact dark matter-dominated objects observed so far. The Pauli exclusion principle limits the number of fermionic dark matter particles that can compose a dSph halo. This results in a well-known lower bound on their particle mass. So far, such bounds were obtained from the analysis of individual dSphs. In this paper, we model dark matter halo density profiles via the semi-analytical approach and analyse the data from eight `classical' dSphs assuming the same mass of dark matter fermion in each object. First, we find out that modelling of Carina dSph results in a much worse fitting quality compared to the other seven objects. From the combined analysis of the kinematic data of the remaining seven `classical' dSphs, we obtain a new $2\sigma$ lower bound of $m\gtrsim 190$ eV on the dark matter fermion mass. In addition, by combining a sub-sample of four dSphs -- Draco, Fornax, Leo I and Sculptor -- we conclude that 220 eV fermionic dark matter appears to be preferred over the standard CDM at about 2$\sigma$ level. However, this result becomes insignificant if all seven objects are included in the analysis. Future improvement of the obtained bound requires more detailed data, both from `classical' and ultra-faint dSphs.