Volume 101, Number 6, March 2013
|Number of page(s)||6|
|Section||Geophysics, Astronomy and Astrophysics|
|Published online||29 March 2013|
Dark-matter decay and the abundance of ultracompact minihalos
1 Department of Physics, Nanjing University - Nanjing, 210093, China
2 School of Astronomy and Space Science, Nanjing University - Nanjing, 210093, China
3 Joint Center for Particle, Nuclear Physics and Cosmology - Nanjing, 210093, China
4 State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS - Beijing 100190, China
Received: 14 December 2012
Accepted: 1 March 2013
Ultracompact minihalos would be formed if there are larger density perturbations (0.0003 < δρ/ρ < 0.3) in the earlier epoch. Their density profile is steeper than the standard dark-matter halos. If dark matter can annihilate or decay into standard particles, e.g., photons, these objects would be the potential astrophysical sources. In order to be consistent with observations, as those from Fermi, the abundance of ultracompact minihalos must be constrained. On the other hand, the formation of these objects has very tight relation with the primordial curvature perturbations on smaller scale, so the fraction of ultracompact minihalos is very important for modern cosmology. In previous works, the studies are focused on the dark-matter annihilation for these objects. But if dark matter is not annihilated, the dark-matter decay is another important possible case. On the other hand, the abundance of ultracompact minihalos is related to many other parameters, such as the mass of dark matter, the decay channels and the density profile of dark-matter halos. One of the important aspects of this work is that we investigate the γ-ray signals from nearby ultracompact minihalos due to dark-matter decay and another important aspect is to study in detail how the different decay channels and density profiles affect the constraints on the abundance of ultracompact minihalos.
PACS: 98.80.-k – Cosmology / 95.36.+x – Dark energy / 98.80.Cq – Particle-theory and field-theory models of the early Universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.)
© EPLA, 2013
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.