%0 Generic %1 lovell2019simulating %A Lovell, Mark R. %A Iakubovskyi, Dmytro %A Barnes, David %A Bose, Sownak %A Frenk, Carlos S. %A Theuns, Tom %A Hellwing, Wojciech A. %D 2019 %K %T Simulating the dark matter decay signal from the Perseus galaxy cluster %U http://arxiv.org/abs/1903.11608 %X The nearby Perseus galaxy cluster is a key target for indirect detection searches for decaying dark matter. We use the C-EAGLE simulations of galaxy clusters to predict the flux, width and shape of a dark matter decay line, paying particular attention to the unexplained 3.55keV line detected in the spectra of some galaxies and clusters, and the upcoming XRISM X-ray observatory mission. We show that the line width in C-EAGLE clusters similar to Perseus is typically 600-800$kms^-1$, and therefore narrower than the amplitude of the velocity dispersion of galaxies in the cluster. Haloes that are significantly disturbed can, however, exhibit galaxy velocity dispersions higher than $1000kms^-1$, and in this case will show a large difference between the line profiles of on- and off-center observations. We show that the line profile is likely to be slightly asymmetric, but still well approximated by a Gaussian at the 10% level, and that the halo asymmetry can lead to fluxes that vary by a factor of two. In summary, we predict that, if the previously reported 3.55keV line detections do originate from dark matter decay, the XRISM mission will detect a line with a roughly Gaussian profile at a rest frame energy of 3.55keV, with a width $>600kms^-1$ and flux approximately in the range $4-9\times10^-8counts/sec/cm^2$.

@misc{lovell2019simulating, abstract = {The nearby Perseus galaxy cluster is a key target for indirect detection searches for decaying dark matter. We use the C-EAGLE simulations of galaxy clusters to predict the flux, width and shape of a dark matter decay line, paying particular attention to the unexplained 3.55keV line detected in the spectra of some galaxies and clusters, and the upcoming XRISM X-ray observatory mission. We show that the line width in C-EAGLE clusters similar to Perseus is typically [600-800]$\mathrm{kms^{-1}}$, and therefore narrower than the amplitude of the velocity dispersion of galaxies in the cluster. Haloes that are significantly disturbed can, however, exhibit galaxy velocity dispersions higher than $1000\mathrm{kms^{-1}}$, and in this case will show a large difference between the line profiles of on- and off-center observations. We show that the line profile is likely to be slightly asymmetric, but still well approximated by a Gaussian at the 10% level, and that the halo asymmetry can lead to fluxes that vary by a factor of two. In summary, we predict that, if the previously reported 3.55keV line detections do originate from dark matter decay, the XRISM mission will detect a line with a roughly Gaussian profile at a rest frame energy of 3.55keV, with a width $>600\mathrm{kms^{-1}}$ and flux approximately in the range $[4-9]\times10^{-8}\mathrm{counts/sec/cm^{2}}$.}, added-at = {2019-03-29T06:18:26.000+0100}, author = {Lovell, Mark R. and Iakubovskyi, Dmytro and Barnes, David and Bose, Sownak and Frenk, Carlos S. and Theuns, Tom and Hellwing, Wojciech A.}, biburl = {https://www.bibsonomy.org/bibtex/2ba24a1d6b7179d0ecbdf210e566cf45a/gpkulkarni}, interhash = {e906d300657fb0990a69f16fe8414947}, intrahash = {ba24a1d6b7179d0ecbdf210e566cf45a}, keywords = {}, note = {cite arxiv:1903.11608Comment: 6 pages and 3 figures, plus 5 pages and 6 figures in supplemental material. Accepted for publication in ApJL}, timestamp = {2019-03-29T06:18:26.000+0100}, title = {Simulating the dark matter decay signal from the Perseus galaxy cluster}, url = {http://arxiv.org/abs/1903.11608}, year = 2019 }