New Limits on Sterile Neutrinos from Suzaku Observations of the Ursa Minor Dwarf Spheroidal Galaxy
نویسندگان
چکیده
We present results of our search for X-ray line emission associated with the radiative decay of the sterile neutrino, a well-motivated dark matter candidate, in Suzaku Observatory spectra of the Ursa Minor dwarf spheroidal galaxy. These data represent the first deep observation of one of these extreme mass-to-light systems and the first dedicated dark matter search using an X-ray telescope. No such emission line is positively detected; and, we place new constraints on the combination of the sterile neutrino mass, mst, and the active-sterile neutrino oscillation mixing angle, θ. Line flux upper limits are derived using a cautious, maximum-likelihood-based approach that, along with the lack of intrinsic X-ray emission, enables us to minimize systematics, and account for those that remain. The limits we derive match or approach the best previous results over the entire 1–20 keV mass range from a single Suzaku observation. These are used to place constraints on the existence of sterile neutrinos with given parameters in the general case, and in the case where they are assumed to constitute all of the dark matter. The allowed range implies that sterile neutrinos remain a viable candidate to make up some – or all – of the dark matter and also explain pulsar kicks and various other astrophysical phenomena.
منابع مشابه
Constraints on the parameters of radiatively decaying dark matter from the dark matter halos of the Milky Way and Ursa Minor
Aims. We improve the earlier restrictions on parameters of the dark matter (DM) in the form of a sterile neutrino. Methods. The results were obtained from non-observing the DM decay line in the X-ray spectrum of the Milky Way (using the recent XMM-Newton PN blank sky data). We also present a similar constraint coming from the recent XMM-Newton observation of Ursa Minor – dark, X-ray quiet dwarf...
متن کاملUpper Limits on Central Black Hole Masses of Globular Clusters from Radio Emission and a Possible Black Hole Detection in the Ursa Minor Dwarf Galaxy
Intermediate mass black holes have been alternatively predicted to be quite common in the centers of globular clusters or nearly impossible to form and retain in the centers of globular clusters. As it has been recently shown that radio observations are currently the most sensitive observational technique for detecting such objects, we have obtained new deep radio observations of Omega Cen, and...
متن کاملA new method of estimating the mass-to-light ratio of the Ursa Minor dwarf spheroidal galaxy
Dwarf satellite galaxies undergo strong tidal forces produced by the main galaxy potential. These forces disturb the satellite, producing asymmetries in its stellar distribution, tidal tail formation, and modifications of the velocity dispersions profiles. Most of these features are observed in the Ursa Minor (UMi) dwarf spheroidal galaxy, which is one of the closest satellites of the Milky Way...
متن کاملThe Low - Mass Stellar IMF at High Redshift : Faint Starsin the Ursa Minor Dwarf Spheroidal Galaxy
متن کامل
Finding Faint Intermediate-mass Black Holes in the Radio Band
We discuss the prospects for detecting faint intermediate-mass black holes, such as those predicted to exist in the cores of globular clusters and dwarf spheroidal galaxies. We briefly summarize the difficulties of stellar dynamical searches, then show that recently discovered relations between black hole mass, X-ray luminosity and radio luminosity imply that in most cases, these black holes sh...
متن کامل