Search Publications
Implications of the Warm Corona and Relativistic Reflection Models for the Soft Excess in Mrk 509
Steiner, James F.; Wilms, Jörn; Ricci, Claudio +15 more
We present the analysis of the first Nuclear Spectroscopic Telescope Array observations (∼220 ks), simultaneous with the last Suzaku observations (∼50 ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in the 1-79 keV X-ray band is dominated by a power-law continuum (Γ ∼ 1.8-1.9), a strong soft e…
XCLUMPY: X-Ray Spectral Model from Clumpy Torus and Its Application to the Circinus Galaxy
Fukazawa, Yasushi; Tanimoto, Atsushi; Ueda, Yoshihiro +3 more
We construct an X-ray spectral model from the clumpy torus in an active galactic nucleus, designated as “XCLUMPY,” utilizing the Monte Carlo simulation for Astrophysics and Cosmology framework. The adopted geometry of the torus is the same as that in Nenkova et al. who assume a power-law distribution of clumps in the radial direction and a normal …
X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars
Safdi, Benjamin R.; Dessert, Christopher; Long, Andrew J.
White dwarf (WD) stars may radiate keV-energy axions produced in their stellar cores. This has been extensively studied as an extra channel by which WDs may cool, with some analyses even suggesting that axions can help explain the observed WD luminosity function. We show that the radiated axions may convert into x rays in the strong magnetic field…
Kinetic Energy Transfer from X-Ray Ultrafast Outflows to Millimeter/Submillimeter Cold Molecular Outflows in Seyfert Galaxies
Kohno, Kotaro; Mizumoto, Misaki; Izumi, Takuma
UltraFast Outflows (UFOs), seen as X-ray blueshifted absorption lines in active galactic nuclei (AGNs), are considered to be a key mechanism for AGN feedback. In this scenario, UFO kinetic energy is transferred into the cold and extended molecular outflow observed at the millimeter/submillimeter wavelength, which blows away the gas and suppresses …
Spectral and Timing Analysis of the Accretion-powered Pulsar 4U 1626-67 Observed with Suzaku and NuSTAR
Enoto, Teruaki; Chakrabarty, Deepto; Terada, Yukikatsu +13 more
We present an analysis of the spectral shape and pulse profile of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and Nuclear Spectroscopic Telescope Array (NuSTAR) during a spin-up state. The pulsar, which experienced a torque reversal to spin-up in 2008, has a spin period of ∼7.7 s. Comparing the phase-averaged spectra obtained with…
Evidence for a Massive Warm-Hot Circumgalactic Medium around NGC 3221
Nicastro, Fabrizio; Mathur, Smita; Gupta, Anjali +3 more
We report a 3.4σ detection of the warm-hot, massive, extended circumgalactic medium (CGM) around an L ⋆ star-forming spiral galaxy NGC 3221, using deep Suzaku observations. The temperature of the gas is 106.1 K, comparable to that of the Milky Way CGM. The spatial extent of the gas is at least 150 kpc. For a β-model of densit…
Evidence for a Merger-induced Shock Wave in ZwCl 0008.8+5215 with Chandra and Suzaku
Di Gennaro, G.; Brunetti, G.; Forman, W. +8 more
We present the results from new deep Chandra (∼410 ks) and Suzaku (∼180 ks) observations of the merging galaxy cluster ZwCl 0008.8+5215 (z = 0.104). Previous radio observations revealed the presence of a double radio relic located diametrically west and east of the cluster center. Using our new Chandra data, we find evidence for the presence of a …
Testing the Kerr Metric with X-Ray Reflection Spectroscopy of Mrk 335 Suzaku Data
Abdikamalov, Askar B.; Ayzenberg, Dimitry; Bambi, Cosimo +4 more
Einstein’s gravity has undergone extensive tests in the weak field gravitational limit, with results in agreement with theoretical predictions. There exist theories beyond general relativity (GR) which modify gravity in the strong field regime but agree with GR in the weak field. Astrophysical black holes are believed to be described by the Kerr m…
A NuSTAR study of the 55 ks hard X-ray pulse-phase modulation in the magnetar 4U 0142+61
Enoto, Teruaki; Makishima, Kazuo; Nakazawa, Kazuhiro +1 more
Archival NuSTAR data of the magnetar 4U 0142+61, acquired in 2014 March for a total time span of 258 ks, were analyzed. This is to reconfirm the 55 ks modulation in the hard X-ray pulse phases of this source, found with a Suzaku observation in 2009 (Makishima et al., 2014, Phys. Rev. Lett., 112, 171102). Indeed, the 10-70 keV X-ray pulsation, dete…
Constraining the Johannsen deformation parameter ɛ3 with black hole x-ray data
Tripathi, Ashutosh; Abdikamalov, Askar B.; Ayzenberg, Dimitry +2 more
We extend our previous work on tests of the Kerr black hole hypothesis using x-ray reflection spectroscopy and we infer observational constraints on the Johannsen deformation parameter ɛ3 . We analyze a NuSTAR observation of the stellar-mass black hole in GS 1354-645, Suzaku data of the supermassive black holes in Ark 564, 1H0419-577, a…