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The Evolution of AGN Host Galaxies: From Blue to Red and the Influence of Large-Scale Structures
Popesso, P.; Lehmer, B. D.; Alexander, D. M. +14 more
We present an analysis of 109 moderate-luminosity (41.9 <= log L0.5-8.0 keV <= 43.7) AGNs in the Extended Chandra Deep Field-South survey, which is drawn from 5549 galaxies from the COMBO-17 and GEMS surveys having 0.4 <= z<= 1.1. These obscured or optically weak AGNs facilitate the study of their host galaxies since the AGN…
Reconciling the Metallicity Distributions of Gamma-Ray Burst, Damped Lyα, and Lyman Break Galaxies at z ≈ 3
Prochaska, J. Xavier; Fynbo, Johan P. U.; Dessauges-Zavadsky, Miroslava +2 more
We test the hypothesis that the host galaxies of long-duration gamma-ray bursts (GRBs) as well as quasar-selected damped Lyα (DLA) systems are drawn from the population of UV-selected star-forming, high-z galaxies (generally referred to as Lyman break galaxies). Specifically, we compare the metallicity distributions of the GRB and DLA populations …
Comparing and Calibrating Black Hole Mass Estimators for Distant Active Galactic Nuclei
Treu, Tommaso; Malkan, Matthew A.; Woo, Jong-Hak +1 more
Black hole mass (MBH) is a fundamental property of active galactic nuclei (AGNs). In the distant universe, MBH is commonly estimated using the Mg II, Hβ, or Hα emission line widths and the optical/UV continuum or line luminosities as proxies for the characteristic velocity and size of the broad-line region. Although they all …
Relativistic Iron Emission Lines in Neutron Star Low-Mass X-Ray Binaries as Probes of Neutron Star Radii
Homan, Jeroen; Miller, Jon M.; Cackett, Edward M. +6 more
Using Suzaku observations of three neutron star low-mass X-ray binaries (Ser X-1, 4U 1820-30, and GX 349+2) we have found broad, asymmetric, relativistic Fe K emission lines in all three objects. These Fe K lines can be well fit by a model for lines from a relativistic accretion disk ("diskline"), allowing a measurement of the inner radius of the …
PPM-Extended (PPMX) - a catalogue of positions and proper motions
Schwan, H.; Scholz, R. -D.; Piskunov, A. E. +3 more
Aims: We build a catalogue PPM-Extended (PPMX) on the ICRS system which is complete down to a well-defined limiting magnitude and contains the best presently available proper motions suited for kinematic studies in the Galaxy.
Methods: We perform a rigorous weighted least-squares adjustment of individual observations, spread over more than a c…
Flows and Nonthermal Velocities in Solar Active Regions Observed with the EUV Imaging Spectrometer on Hinode: A Tracer of Active Region Sources of Heliospheric Magnetic Fields?
Culhane, J. L.; Doschek, G. A.; Mariska, J. T. +4 more
From Doppler velocity maps of active regions constructed from spectra obtained by the EUV Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km s-1) that can persist for at least a day. These outflows occur in areas of active regions that are faint in coronal spectral lines formed at typical qui…
Chandra unveils a binary active galactic nucleus in Mrk 463
Guainazzi, Matteo; Bianchi, Stefano; Piconcelli, Enrico +2 more
We analyse Chandra, XMM-Newton and Hubble Space Telescope (HST) data of the double-nucleus Ultraluminous Infrared Galaxy (ULIRG), Mrk 463. The Chandra detection of two luminous (L2-10keV = 1.5 × 1043 and 3.8 × 1042 erg cm-2 s-1), unresolved nuclei in Mrk 463 indicates that this galaxy hosts a …
Evolution of tidal disruption candidates discovered by XMM-Newton
Read, A. M.; Esquej, P.; Freyberg, M. J. +8 more
Context: It has been demonstrated that active galactic nuclei are powered by gas accretion onto supermassive black holes located at their centres. The paradigm that the nuclei of inactive galaxies are also occupied by black holes was predicted long ago by theory. In the past decade, this conjecture was confirmed by the discovery of giant-amplitude…
The fraction of second generation stars in globular clusters from the analysis of the horizontal branch
D'Antona, F.; Caloi, V.
The majority of globular clusters show chemical inhomogeneities in the composition of their stars, apparently due to a second stellar generation in which the forming gas is enriched by hot-CNO cycled material processed in stars belonging to a first stellar generation. Clearly this evidence prompts questions on the modalities of formation of globul…
Three-dimensional MHD Simulation of the 2003 October 28 Coronal Mass Ejection: Comparison with LASCO Coronagraph Observations
Vourlidas, Angelos; Lugaz, Noé; Roussev, Ilia I. +6 more
We numerically model the coronal mass ejection (CME) event of 2003 October 28 that erupted from AR 10486 and propagated to Earth in less than 20 hr, causing severe geomagnetic storms. The magnetohydrodynamic (MHD) model is formulated by first arriving at a steady state corona and solar wind employing synoptic magnetograms. We initiate two CMEs fro…