Search Publications
The Remarkable X-Ray Spectrum of the Broad-Line Radio Galaxy 3C 445
Reeves, J. N.; Braito, V.; Sambruna, R. M.
We present the results of the analysis of an archival 15 ks XMM-Newton observation of the nearby (z=0.057) radio-loud source 3C 445, optically classified as a broad-line radio galaxy. While the RGS data are of insufficient quality to allow a meaningful analysis, the EPIC data show a remarkable X-ray spectrum. The 2-10 keV continuum is described by…
Deep Chandra and Multicolor HST Observations of the Jets of 3C 371 and PKS 2201+044
Maraschi, L.; Cheung, C. C.; Tavecchio, F. +3 more
This paper presents multiwavelength imaging and broadband spectroscopy of the relativistic jets in the two nearby radio galaxies 3C 371 and PKS 2201+044, acquired with Chandra, HST, VLA, and MERLIN. Radio polarization is also presented for 3C 371. The two sources stand out as ``intermediate'' between FR I and FR II type galaxies; their cores are c…
Spectropolarimetric Observations of the Ca II λ8498 and λ8542 in the Quiet Sun
Pietarila, A.; Socas-Navarro, H.; Bogdan, T.
The Ca II infrared triplet is one of the few magnetically sensitive chromospheric lines available for ground-based observations. We present spectropolarimetric observations of the 8498 and 8542 Å lines in a quiet Sun region near a decaying active region and compare the results with a simulation of the lines in a high plasma-β regime. Cluster analy…
Fe K Line Profile in Low-Redshift Quasars: Average Shape and Eddington Ratio Dependence
Ho, Luis C.; Terashima, Yuichi; Inoue, Hirohiko
We analyze X-ray spectra of 43 Palomar-Green quasars observed with XMM-Newton in order to investigate their mean Fe K line profile and its dependence on physical properties. The continuum spectra of 39 objects are well reproduced by a model consisting of a power law and a blackbody modified by Galactic absorption. The spectra of the remaining four…
Integral Field Spectroscopy of the Extended Emission-Line Region of 4C 37.43
Fu, Hai; Stockton, Alan
We present Gemini integral field spectroscopy and Keck II long-slit spectroscopy of the extended emission-line region (EELR) around the quasar 4C 37.43. The velocity structure of the ionized gas is complex and cannot be explained globally by a simple dynamical model. The spectra from the clouds are inconsistent with shock or ``shock + precursor'' …
The Nature of Optical Features in the Inner Region of the 3C 48 Host Galaxy
Fu, Hai; Stockton, Alan; Canalizo, Gabriela +1 more
The well-known quasar 3C 48 is the most powerful compact steep-spectrum radio-loud QSO at low redshifts. It also has two unusual optical features within the radius of the radio jet (~1"): (1) an anomalous, high-velocity narrow-line component, and (2) a bright continuum peak (3C 48A) ~1" northeast of the quasar. Both of these optical features have …
Accretion Disk Illumination in Schwarzschild and Kerr Geometries: Fitting Formulae
Fukumura, Keigo; Kazanas, Demosthenes
We describe the methodology and compute the illumination of geometrically thin accretion disks around black holes of arbitrary spin parameter a exposed to the radiation of a pointlike isotropic source at arbitrary height above the disk on its symmetry axis. We then provide analytic fitting formulae for the illumination as a function of the source …
Dynamical Models of Elliptical Galaxies in z = 0.5 Clusters. I. Data-Model Comparison and Evolution of Galaxy Rotation
van Dokkum, Pieter G.; van der Marel, Roeland P.
We present spatially resolved stellar rotation velocity and velocity dispersion profiles from Keck/LRIS absorption-line spectra for 25 galaxies, mostly visually classified ellipticals, in three clusters at z~0.5. We interpret the kinematical data and HST photometry using oblate axisymmetric two-integral f(E,Lz) dynamical models based on…
Radio Lobes of Pictor A: An X-Ray Spatially Resolved Study
Brunetti, Gianfranco; Grandi, Paola; Migliori, Giulia +2 more
A new XMM-Newton observation has made possible a detailed study of both lobes of the radio galaxy Pictor A. Their X-ray emission is of nonthermal origin and due to inverse Compton scattering of cosmic microwave background (CMB) photons by relativistic electrons in the lobes, as previously found. In both lobes, the equipartition magnetic field (B
Radial Profile and Lognormal Fluctuations of the Intracluster Medium as the Origin of Systematic Bias in Spectroscopic Temperature
Dolag, Klaus; Suto, Yasushi; Kitayama, Tetsu +4 more
The origin of the recently reported systematic bias in the spectroscopic temperature of galaxy clusters is investigated using a cosmological hydrodynamic simulation. We find that the local inhomogeneities of the gas temperature and density, after being corrected for their global radial profiles, have a nearly universal distribution that resembles …