Search Publications
Detection and characterization of quasiperiodic oscillations in the Seyfert galaxy NGC 4151
Yongkang, Yan; Peng, Zhang; Zhou, Lu +6 more
This study aims to detect and characterize quasiperiodic oscillations (QPOs) signals in x-ray observations of NGC 4151. We employed the weighted wavelet Z-transform and Lomb-Scargle periodogram methods for our analysis. QPO signals with frequencies of
Probing orbits of stellar mass objects deep in galactic nuclei with quasiperiodic eruptions
Pan, Zhen; Zhou, Cong; Huang, Lei +2 more
Quasiperiodic eruptions (QPEs) are intense, repeating, soft x-ray bursts with recurrence times of about a few to ten hours from nearby galactic nuclei. The origin of QPEs is still unclear. In this work, we investigate the extreme mass ratio inspiral (EMRI) + accretion disk model, where the disk is formed from a previous tidal disruption event (TDE…
Probing orbits of stellar mass objects deep in galactic nuclei with quasiperiodic eruptions. II. Population analysis
Pan, Zhen; Zhou, Cong; Huang, Lei +2 more
Quasiperiodic eruptions (QPEs) are intense repeating soft x-ray bursts with recurrence times about a few hours to a few weeks from galactic nuclei. Though the debates on the origin of QPEs have not completely settled down, more and more analyses favor the interpretation that QPEs are the result of collisions between a stellar mass object (a stella…
Multimessenger search for electrophilic feebly interacting particles from supernovae
Carenza, Pierluca; Balaji, Shyam; Luque, Pedro De la Torre
We study MeV-scale electrophilic feebly interacting particles (FIPs), that may be abundantly produced in supernova explosions, escape the star and decay into electrons and positrons. This exotic injection of leptons in the Milky Way leaves an imprint in both photon and cosmic ray fluxes. Specifically, positrons lose energy and annihilate almost at…
Robust constraints on feebly interacting particles using XMM-Newton
Carenza, Pierluca; Balaji, Shyam; Luque, Pedro De la Torre
During galactic supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) may be produced. In this work we analyze electrophilic FIPs with masses in the MeV-range that escape from SN and decay into electron-positron pairs, causing an exotic leptonic injection. This contribution adds up to known components, leading to an unex…
Refining Galactic primordial black hole evaporation constraints
Balaji, Shyam; Koechler, Jordan; Luque, Pedro De la Torre
We revisit the role of primordial black holes (PBHs) as potential dark matter (DM) candidates, particularly focusing on light asteroid-mass PBHs. These PBHs are expected to emit particles through Hawking evaporation that can generate cosmic rays (CRs), eventually producing other secondary radiations through their propagation in the Milky Way, in a…
Cosmological constraints from type-I radio-loud quasars
Chang, N.; Huang, L.; Tu, Z. Y. +3 more
We obtain a sample of 1192 type-I quasars with the UV-optical, radio, and x-ray waveband coverage, which combined with the data from Huang and Chang [Mon. Not. R. Astron. Soc. 515, 1358 (2022), 10.1093/mnras/stac1451] and other matching objects of SDSS-DR16 with FIRST, XMM-Newton, and Chandra Source Catalog, and a sample of 407 flat-spectrum radio…
Search for primordial black hole dark matter with x-ray spectroscopic and imaging satellite experiments and prospects for future satellite missions
Santangelo, Andrea; Malyshev, Denys; Moulin, Emmanuel
Ultralight primordial black holes (PBHs) in the mass range of 1016- 1022 g are allowed by current observations to constitute a significant fraction, if not all, of the dark matter in the Universe. In this work, we present limits on ultralight, nonrotating PBHs which arise from the nondetection of the Hawking radiation signals…
Constraining the Konoplya-Rezzolla-Zhidenko deformation parameters. II. Limits from stellar-mass black hole x-ray data
Yu, Zhibo; Tripathi, Ashutosh; Abdikamalov, Askar B. +5 more
Astrophysical black holes are thought to be the Kerr black holes predicted by general relativity, but macroscopic deviations from the Kerr solution can be expected from a number of scenarios involving new physics. In Paper I, we studied the reflection features in NuSTAR and XMM-Newton spectra of the supermassive black hole at the center of the gal…
Constraining the Konoplya-Rezzolla-Zhidenko deformation parameters: Limits from supermassive black hole x-ray data
Tripathi, Ashutosh; Abdikamalov, Askar B.; Ayzenberg, Dimitry +2 more
X-ray reflection spectroscopy is a powerful technique for probing the nature of gravity around black holes in the so-called strong-field regime. One popular approach is to look at theory-agnostic deviations away from the Kerr solution, which is the only astrophysically relevant black hole solution within classical general relativity, in order to v…