Imperial College London


Faculty of Natural SciencesDepartment of Physics

Professor of Astrostatistics; CLCC Director



+44 (0)20 7594 7793r.trotta Website CV




Mrs Sheila Ekudo +44 (0)20 7594 2086




1009Blackett LaboratorySouth Kensington Campus






BibTex format

author = {Arina, C and Hamann, J and Trotta, R and Wong, YYY},
doi = {03/008},
journal = {Journal of Cosmology and Astroparticle Physics},
title = {Evidence for dark matter modulation in CoGeNT?},
url = {},
volume = {2012},
year = {2012}

RIS format (EndNote, RefMan)

AB - We investigate the question of whether the recent modulation signal claimed by CoGeNT is best explained by the dark matter (DM) hypothesis from a Bayesian model comparison perspective. We consider five phenomenological explanations for the data: no modulation signal, modulation due to DM, modulation due to DM compatible with the total CoGeNT rate, and a signal coming from other physics with a free phase but annual period, or with a free phase and a free period. In each scenario, we assign to the free parameters physically motivated priors. We find that while the DM models are weakly preferred to the no modulation model, but when compared to models where the modulation is due to other physics, the DM hypothesis is favoured with odds ranging from 185:1 to 560:1. This result is robust even when astrophysical uncertainties are taken into account and the impact of priors assessed. Interestingly, the odds for the DM model in which the modulation signal is compatible with the total rate against a DM model in which this prior is not implemented is only 5:8, in spite of the former's prediction of a modulation amplitude in the energy range 0.9 → 3.0 keVee that is significantly smaller than the value observed by CoGeNT. Classical hypothesis testing also rules out the null hypothesis of no modulation at the 1.6σ to 2.3σ level, depending on the details of the alternative. Lastly, we investigate whether anisotropic velocity distributions can help to mitigate the tension between the CoGeNT total and modulated rates, and find encouraging results.
AU - Arina,C
AU - Hamann,J
AU - Trotta,R
AU - Wong,YYY
DO - 03/008
PY - 2012///
SN - 1475-7516
TI - Evidence for dark matter modulation in CoGeNT?
T2 - Journal of Cosmology and Astroparticle Physics
UR -
UR -
VL - 2012
ER -