Search Publications
Search for astrophysical rotating Ellis wormholes with x-ray reflection spectroscopy
Bambi, Cosimo; Zhou, Menglei; Cardenas-Avendano, Alejandro +2 more
Recently, two of us have found numerically rotating Ellis wormholes as solutions of four-dimensional Einstein gravity coupled to a phantom field. In this paper, we investigate possible observational signatures to identify similar objects in the Universe. These symmetric wormholes have a mass and are compact, so they may look like black holes. We s…
Iron Kα line of Kerr black holes with scalar hair
Bambi, Cosimo; Zhou, Menglei; Ni, Yueying +3 more
Recently, a family of hairy black holes in 4-dimensional Einstein gravity minimally coupled to a complex, massive scalar field was discovered [1]. Besides the mass M and spin angular momentum J, these objects are characterized by a Noether charge Q, measuring the amount of scalar hair, which is not associated to a Gauss law and cannot be measured …
The Interaction of the Fermi Bubbles with the Milky Way’s Hot Gas Halo
Bregman, Joel N.; Miller, Matthew J.
The Fermi bubbles are two lobes filled with non-thermal particles that emit gamma rays, extend ≈ 10 {{kpc}} vertically from the Galactic center, and formed from either nuclear star formation or accretion activity on Sgr A*. Simulations predict a range of shock strengths as the bubbles expand into the surrounding hot gas halo ({T}{halo}≈…
The Evolution of the Intracluster Medium Metallicity in Sunyaev Zel’dovich-selected Galaxy Clusters at 0 < z < 1.5
Hlavacek-Larrondo, J.; Bleem, L. E.; Stalder, B. +16 more
We present the results of an X-ray spectral analysis of 153 galaxy clusters observed with the Chandra, XMM-Newton, and Suzaku space telescopes. These clusters, which span 0 < z < 1.5, were drawn from a larger, mass-selected sample of galaxy clusters discovered in the 2500 square degree South Pole Telescope Sunyaev Zel’dovich (SPT-SZ) survey.…
A shock front at the radio relic of Abell 2744
Kneib, J. -P.; Eckert, D.; Vazza, F. +5 more
Radio relics are Mpc-scale diffuse radio sources at the peripheries of galaxy clusters which are thought to trace outgoing merger shocks. We present XMM-Newton and Suzaku observations of the galaxy cluster Abell 2744 (z = 0.306), which reveal the presence of a shock front 1.5 Mpc east of the cluster core. The surface-brightness jump coincides with…
A comprehensive analysis of the hard X-ray spectra of bright Seyfert galaxies
Papadakis, I. E.; Paltani, S.; Walter, R. +7 more
Hard X-ray spectra of 28 bright Seyfert galaxies observed with INTEGRAL were analysed together with the X-ray spectra from XMM-Newton, Suzaku and RXTE. These broad-band data were fitted with a model assuming a thermal Comptonization as a primary continuum component. We tested several model options through a fitting of the Comptonized continuum acc…
The XMM Cluster Outskirts Project (X-COP): Physical conditions of Abell 2142 up to the virial radius
Hurier, G.; Pointecouteau, E.; Rossetti, M. +9 more
Context. Galaxy clusters are continuously growing through the accretion of matter in their outskirts. This process induces inhomogeneities in the gas density distribution (clumping) that need to be taken into account to recover the physical properties of the intracluster medium (ICM) at large radii.
Aims: We studied the thermodynamic properti…
Short-term X-ray spectral variability of the quasar PDS 456 observed in a low-flux state
Tombesi, F.; Reeves, J. N.; Braito, V. +4 more
We present a detailed analysis of a recent, 2013 Suzaku campaign on the nearby (z = 0.184) luminous (Lbol ∼ 1047 erg s-1) quasar PDS 456. This consisted of three observations, covering a total duration of ∼1 Ms and a net exposure of 455 ks. During these observations, the X-ray flux was unusually low, suppressed by …
Suzaku Observations of Moderately Obscured (Compton-thin) Active Galactic Nuclei Selected by Swift/BAT Hard X-ray Survey
Ueda, Yoshihiro; Kawamuro, Taiki; Ricci, Claudio +2 more
We report the results obtained by a systematic, broadband (0.5-150 keV) X-ray spectral analysis of moderately obscured (Compton-thin, 22≤slant {log}{N}{{H}}< 24) active galactic nuclei (AGNs) observed with Suzaku and Swift/Burst Alert Telescope (BAT). Our sample consists of 45 local AGNs at z< 0.1 with {log}{L}14-195{keV
Revealing the accretion disc corona in Mrk 335 with multi-epoch X-ray spectroscopy
Ballantyne, D. R.; Keek, L.
Active galactic nuclei host an accretion disc with an X-ray producing corona around a supermassive black hole. In bright sources, such as the Seyfert 1 galaxy Mrk 335, reflection of the coronal emission off the accretion disc has been observed. Reflection produces spectral features such as an Fe Kα emission line, which allow for properties of the …