Dark matter can be cold warm or hot

In summary, the paper discusses the possibility of a two-component dark matter scenario where the second component is a non-cold thermal relic. Using various measurements and data, the paper presents upper limits on the energy density of the non-cold dark relic for different ranges of velocity dispersions. The results show that the fraction of non-cold dark matter is limited to be less than 0.29 (0.23) for fermions (bosons) with masses in the range of 1-10 keV, and less than 0.43 (0.45) for masses in the range of 10-100 keV. The point of this paper is to explore the possibility of a mixture of energies for dark matter, which is
  • #1
wolram
Gold Member
Dearly Missed
4,446
558
According to this paper https://arxiv.org/pdf/1701.03128.pdf is this a fudge factor or can we have a mixture of energies for DM.

Abstract. Various particle physics models suggest that, besides the (nearly) cold dark matter that accounts for current observations, additional but sub-dominant dark relics might exist. These could be warm, hot, or even contribute as dark radiation. We present here a comprehensive study of two-component dark matter scenarios, where the first component is assumed to be cold, and the second is a non-cold thermal relic. Considering the cases where the non-cold dark matter species could be either a fermion or a boson, we derive consistent upper limits on the non-cold dark relic energy density for a very large range of velocity dispersions, covering the entire range from dark radiation to cold dark matter. To this end, we employ the latest Planck Cosmic Microwave Background data, the recent BOSS DR11 and other Baryon Acoustic Oscillation measurements, and also constraints on the number of Milky Way satellites, the latter of which provides a measure of the suppression of the matter power spectrum at the smallest scales due to the free-streaming of the non-cold dark matter component. We present the results on the fraction fncdm of non-cold dark matter with respect to the total dark matter for different ranges of the non-cold dark matter masses. We find that the 2σ limits for non-cold dark matter particles with masses in the range 1–10 keV are fncdm ≤ 0.29 (0.23) for fermions (bosons), and for masses in the 10–100 keV range they are fncdm ≤ 0.43 (0.45), respectively
 
Space news on Phys.org
  • #2
Wolram, what is the point of this?

You keep posting these kinds of messages with zero follow through. Of your last ten (neglecting today's) you never responded to eight of them. Having us write lengthy replies only to be ignored is very annoying.
 
  • Like
Likes weirdoguy
  • #3
wolram said:
can we have a mixture of energies for DM

The nature of dark matter is still an open area of research, so the general answer to questions of this form is "we don't know yet". Which makes them pointless for PF discussion threads. Thread closed.
 

FAQ: Dark matter can be cold warm or hot

What is dark matter?

Dark matter is a type of matter that does not emit or absorb light, making it invisible to telescopes. It is believed to make up about 85% of the total matter in the universe.

What is the difference between cold, warm, and hot dark matter?

Cold dark matter refers to particles that move slowly and clump together, forming structures like galaxies. Warm dark matter moves faster and is more spread out, while hot dark matter moves at very high speeds and is evenly distributed throughout the universe.

How do scientists study dark matter?

Scientists use various methods to study dark matter, including observing its gravitational effects on visible matter, using computer simulations, and studying the cosmic microwave background radiation.

What is the evidence for the existence of dark matter?

The main evidence for dark matter comes from the observation of the rotational speeds of galaxies, which cannot be explained by the visible matter alone. Other evidence includes the gravitational lensing of light and the distribution of matter in the universe.

What is the significance of understanding dark matter?

Understanding dark matter is crucial to understanding the formation and evolution of the universe. It also has implications for the future of the universe and the fate of galaxies. Additionally, studying dark matter can provide insights into the fundamental laws of physics.

Similar threads

Replies
13
Views
2K
Replies
7
Views
2K
Replies
1
Views
1K
Replies
20
Views
3K
Replies
1
Views
3K
Replies
46
Views
6K
Replies
2
Views
1K
Back
Top