scholarly journals Constraints on dark matter annihilation and its equation of state after Planck data

2014 ◽  
Vol 29 (37) ◽  
pp. 1440004 ◽  
Author(s):  
Lixin Xu
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Dynamic Measurements ◽  
Dark Matter Annihilation ◽  
Planck Data ◽  
Λcdm Model

In this paper, the annihilation of dark matter (DM) fdϵ0 with nonzero equation of state (EoS) w dm was studied by using the currently available cosmic observations which include geometric and dynamic measurements. The constrained results show they are anti-correlated and are [Formula: see text] and [Formula: see text], respectively in 1σ regions. With the inclusion of possible annihilation of DM, no significant deviation from ΛCDM model was found in the 1σ region.

scholarly journals Constraints on Dark Matter Annihilation by Synchrotron Emission based on Planck Data

2017 ◽  
Vol 901 ◽  
pp. 012019
Author(s):  
Chalit Muanglay ◽  
Maneenate Wechakama ◽  
Brandon K. Cantlay
Keyword(s):  
Dark Matter ◽  
Synchrotron Emission ◽  
Dark Matter Annihilation ◽  
Planck Data

scholarly journals GEOMETRICAL DIAGNOSTIC FOR THE GENERALIZED CHAPLYGIN GAS MODEL

2009 ◽  
Vol 18 (11) ◽  
pp. 1741-1748 ◽  
Author(s):  
JIANBO LU ◽  
LIXIN XU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Diagnostic Method ◽  
Chaplygin Gas ◽  
Shift Parameter ◽  
Generalized Chaplygin Gas ◽  
Λcdm Model ◽  
Current Equation

A new diagnostic method, Om, is applied to the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy. On the basis of the recently observed data — the Union supernovae, the observational Hubble data, the SDSS baryon acoustic peak and the five-year WMAP shift parameter — we show the discriminations between the GCG model and the ΛCDM model. Furthermore, it is calculated that the current equation of state of dark energy w 0de = -0.964, according to the GCG model.

scholarly journals Does the reionization model influence the constraints on dark matter decay or annihilation?

2021 ◽  
Vol 2021 (12) ◽  
pp. 034
Author(s):  
Lu Chen ◽  
Ke Wang
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Power Spectra ◽  
Microwave Background ◽  
Dark Matter Annihilation ◽  
Planck Data ◽  
Upper Limit ◽  
History Of

Abstract If dark matter decay or annihilate, a large amount of energy and particles would be released into the cosmic plasma. Therefore, they could modify the thermal and ionization history of our universe, then leave footprints on the cosmic microwave background power spectra. In this paper, we take dark matter annihilation as an example and investigate whether different reionization models influence the constraints on dark matter annihilation. We consider the ionization history including both dark matter annihilation and star formation, then put constraints on DM annihilation. Combining the latest Planck data, BAO data, SNIa measurement, Q HII constraints from observations of quasars, as well as the star formation rate density from UV and IR data, the optical depth is τ = 0.0571+0.0005 -0.0006 at 68%C.L. and the upper limit of ϵ0 f d reads 2.7765 × 10-24 at 95%C.L.. By comparison, we also constrain dark matter annihilation in the instantaneous reionization model from the same data combination except the Q HII constraints and star formation rate density. We get τ = 0.0559+0.0069 -0.0076 at 68%C.L. and the upper limit of ϵ0 f d is 2.8468 × 10-24 at 95%C.L.. This indicates various reionization models have little influence (≲ 2.5%) on constraining parameters of dark matter decay or annihilation.

scholarly journals Celestial-body focused dark matter annihilation throughout the Galaxy

2021 ◽  
Vol 103 (7) ◽  
Author(s):  
Rebecca K. Leane ◽  
Tim Linden ◽  
Payel Mukhopadhyay ◽  
Natalia Toro
Keyword(s):  
Dark Matter ◽  
Celestial Body ◽  
Dark Matter Annihilation ◽  
The Galaxy

Equation of state of strange stars with admissible dark matter: Derivation from galactic rotational curves

2021 ◽  
Vol 342 (1-2) ◽  
pp. 310-314
Author(s):  
Moisés Razeira ◽  
Fabio Köpp ◽  
Guilherme Volkmer ◽  
Magno Machado ◽  
Dimiter Hadjimichef ◽  
...  
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Strange Stars

An excess radio signal in the Abell 4038 cluster

2020 ◽  
Vol 500 (4) ◽  
pp. 5583-5588
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Spectral Data ◽  
Cross Section ◽  
Radio Signal ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Annihilation Cross Section ◽  
Radio Continuum ◽  
Test Statistic ◽  
Dark Matter Annihilation

ABSTRACT In the past decade, various instruments, such as the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope, the Alpha Magnetic Spectrometer (AMS) and the Dark Matter Particle Explorer(DAMPE), have been used to detect the signals of annihilating dark matter in our Galaxy. Although some excesses of gamma rays, antiprotons and electrons/positrons have been reported and are claimed to be dark matter signals, the uncertainties of the contributions of Galactic pulsars are still too large to confirm the claims. In this paper, we report on a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming a thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we obtain very large test statistic (TS) values, TS > 45, for four popular annihilation channels, which correspond to more than 6σ statistical preference. This reveals a possible potential signal of annihilating dark matter. In particular, our results are also consistent with the recent claims of dark matter mass, m ≈ 30–50 GeV, annihilating via the $\rm b\bar{b}$ quark channel with the thermal annihilation cross-section. However, at this time, we cannot exclude the possibility that a better background cosmic ray model could explain the spectral data without recourse to dark matter annihilations.

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