Searches for 3.5 keV Absorption Features in Cluster AGN Spectra
Monthly Notices of the Royal Astronomical Society Blackwell Publishing Inc.
Abstract:
We investigate possible evidence for a spectral dip around 3.5 keV in central
cluster AGNs, motivated by previous results for archival Chandra observations
of the Perseus cluster and the general interest in novel spectral features
around 3.5 keV that may arise from dark matter physics. We use two deep Chandra
observations of the Perseus and Virgo clusters that have recently been made
public. In both cases, mild improvements in the fit ($\Delta \chi^2 = 4.2$ and
$\Delta \chi^2 = 2.5$) are found by including such a dip at 3.5 keV into the
spectrum. A comparable result ($\Delta \chi^2 = 6.5$) is found re-analysing
archival on-axis Chandra ACIS-S observations of the centre of the Perseus
cluster.
