Search Publications
The supermassive black hole of FornaxA
Saglia, R. P.; Nowak, N.; Davies, R. I. +3 more
The radio galaxy FornaxA (NGC 1316) is a prominent merger remnant in the outskirts of the Fornax cluster. Its giant radio lobes suggest the presence of a powerful active galactic nuclei (AGN) and thus a central supermassive black hole (SMBH). FornaxA now seems to be in a transition state between active black hole growth and quiescence, as indicate…
Using Global Simulations to Relate the Three-Part Structure of Coronal Mass Ejections to In Situ Signatures
Riley, Pete; Mikić, Zoran; Lionello, Roberto +1 more
White-light observations of coronal mass ejections (CMEs) often show the classic "three-part" structure consisting of (1) a bright front; (2) a dark cavity; and (3) a bright, compact core. It has proven difficult to unambiguously associate these features with in situ measurements of interplanetary CMEs (ICMEs), in all but a few cases. In this stud…
On the geometry of broad emission region in quasars
Falomo, R.; Treves, A.; Decarli, R. +1 more
We study the geometry of the Hβ broad emission region by comparing the MBH values derived from Hβ through the virial relation with those obtained from the host galaxy luminosity in a sample of 36 low-redshift (z ~ 0.3) quasars. This comparison lets us infer the geometrical factor f needed to deproject the line-of-sight velocity componen…
Open magnetic flux tubes in the corona and the transport of solar energetic particles
Krucker, S.; Klein, K. -L.; Lointier, G. +1 more
We investigate how magnetic fields guide energetic particles through the corona into interplanetary space and eventually to a spacecraft near the Earth. A set of seven simple particle events is studied, where energetic electrons (30-500 keV; Wind spacecraft) or protons (5-55 MeV; SoHO) were released together with low-energy electron beams producin…
A Molecular Einstein Ring at z = 4.12: Imaging the Dynamics of a Quasar Host Galaxy Through a Cosmic Lens
Lewis, Geraint F.; Walter, Fabian; Carilli, Christopher L. +4 more
We present high-resolution (0.3'') Very Large Array imaging of the molecular gas in the host galaxy of the high-redshift quasar PSS J2322+1944 (z = 4.12). These observations confirm that the molecular gas (CO) in the host galaxy of this quasar is lensed into a full Einstein ring and reveal the internal gas dynamics in this system. The ring has a d…
The dark matter environment of the Abell 901/902 supercluster: a weak lensing analysis of the HST STAGES survey
Bell, Eric F.; Wisotzki, Lutz; Wolf, Christian +21 more
We present a high-resolution dark matter reconstruction of the z = 0.165 Abell 901/902 supercluster from a weak lensing analysis of the Hubble Space Telescope STAGES survey. We detect the four main structures of the supercluster at high significance, resolving substructure within and between the clusters. We find that the distribution of dark matt…
V838 Monocerotis: A Geometric Distance from Hubble Space Telescope Polarimetric Imaging of its Light Echo
White, Richard L.; Sparks, William B.; Bond, Howard E. +10 more
Following the outburst of the unusual variable star V838 Monocerotis in 2002, a spectacular light echo appeared. A light echo provides the possibility of direct geometric distance determination, because it should contain a ring of highly linearly polarized light at a linear radius of ct, where t is the time since the outburst. We present imaging p…
HDO and H2O vertical distributions and isotopic ratio in the Venus mesosphere by Solar Occultation at Infrared spectrometer on board Venus Express
Montmessin, F.; Fedorova, A.; Korablev, O. +8 more
Vertical distributions of the molecular density and mixing ratios of H2O and HDO in the Venus mesosphere have been obtained using Solar Occultation at Infrared (SOIR), a high-resolution (with λ/δλ ~ 20,000) echelle spectrometer on Venus Express. The atmosphere is sounded in solar occultation in the range of altitudes from 65 to 130 km. …
Spatial Relationship between Solar Flares and Coronal Mass Ejections
Howard, R. A.; Gopalswamy, N.; Michalek, G. +2 more
We report on the spatial relationship between solar flares and coronal mass ejections (CMEs) observed during 1996-2005 inclusive. We identified 496 flare-CME pairs considering limb flares (distance from central meridian >=45°) with soft X-ray flare size >=C3 level. The CMEs were detected by the Large Angle and Spectrometric Coronagraph (LASC…
The drying of Titan's dunes: Titan's methane hydrology and its impact on atmospheric circulation
Mitchell, Jonathan L.
We explore the effect of a finite reservoir of methane on Titan's atmospheric circulation, precipitation patterns, and surface methane content. We develop a soil model that accounts for the methane cycle in the surface-atmosphere system, and we implement this surface model in a two-dimensional model of the Titan's atmosphere. Seasonal oscillations…