Search Publications
Resurrecting Hitomi for Decaying Dark Matter and Forecasting Leading Sensitivity for XRISM
Safdi, Benjamin R.; Dessert, Christopher; Rodd, Nicholas L. +1 more
The Hitomi x-ray satellite mission carried unique high-resolution spectrometers that were set to revolutionize the search for sterile neutrino dark matter (DM) by looking for narrow x-ray lines arising from DM decays. Unfortunately, the satellite was lost shortly after launch, and to date the only analysis using Hitomi for DM decay used data taken…
Deep Search for Decaying Dark Matter with XMM-Newton Blank-Sky Observations
Safdi, Benjamin R.; Foster, Joshua W.; Kongsore, Marius +4 more
Sterile neutrinos with masses in the keV range are well-motivated extensions to the Standard Model that could explain the observed neutrino masses while also making up the dark matter (DM) of the universe. If sterile neutrinos are DM then they may slowly decay into active neutrinos and photons, giving rise to the possibility of their detection thr…
Axion Emission Can Explain a New Hard X-Ray Excess from Nearby Isolated Neutron Stars
Buschmann, Malte; Safdi, Benjamin R.; Dessert, Christopher +1 more
Axions may be produced thermally inside the cores of neutron stars (NSs), escape the stars due to their feeble interactions with matter, and subsequently convert into x rays in the magnetic fields surrounding the stars. We show that a recently discovered excess of hard x-ray emission in the 2-8 keV energy range from the nearby magnificent seven is…
Testing General Relativity with the Reflection Spectrum of the Supermassive Black Hole in 1H0707-495
Cao, Zheng; Bambi, Cosimo; Nampalliwar, Sourabh +2 more
Recently, we have extended the x-ray reflection model relxill to test the spacetime metric in the strong gravitational field of astrophysical black holes. In the present Letter, we employ this extended model to analyze XMM-Newton, NuSTAR, and Swift data of the supermassive black hole in 1H0707-495 and test deviations from a Kerr metric parametrize…
Checking the Dark Matter Origin of a 3.53 keV Line with the Milky Way Center
Boyarsky, A.; Franse, J.; Iakubovskyi, D. +1 more
We detect a line at 3.539 ±0.011 keV in the deep exposure data set of the Galactic center region, observed with the x-ray multi-mirror mission Newton. The dark matter interpretation of the signal observed in the Perseus galaxy cluster, the Andromeda galaxy [A. Boyarsky et al., Phys. Rev. Lett. 113, 251301 (2014)], and in the stacked spectra of gal…
Unidentified Line in X-Ray Spectra of the Andromeda Galaxy and Perseus Galaxy Cluster
Boyarsky, A.; Franse, J.; Iakubovskyi, D. +1 more
We report a weak line at 3.52 ±0.02 keV in x-ray spectra of the Andromeda galaxy and the Perseus galaxy cluster observed by the metal-oxide-silicon (MOS) and p -n (PN) CCD cameras of the XMM-Newton telescope. This line is not known as an atomic line in the spectra of galaxies or clusters. It becomes stronger towards the centers of the objects; is …
Revisiting Algorithms for Generating Surrogate Time Series
Papadakis, I. E.; Brinkmann, W.; Gliozzi, M. +1 more
The method of surrogates is one of the key concepts of nonlinear data analysis. Here, we demonstrate that commonly used algorithms for generating surrogates often fail to generate truly linear time series. Rather, they create surrogate realizations with Fourier phase correlations leading to nondetections of nonlinearities. We argue that reliable s…
Strategy for Searching for a Dark Matter Sterile Neutrino
Neronov, A.; Boyarsky, A.; Ruchayskiy, O. +2 more
We propose a strategy for how to look for dark matter particles possessing a radiative decay channel and derive constraints on their parameters from observations of x rays from our own Galaxy and its dwarf satellites. When applied to sterile neutrinos in the keV mass range this approach gives a significant improvement to restrictions on neutrino p…