Search Publications
Missions
Journals
Publication Years
Seyfert's Sextet: a Slowly Dissolving Stephan's Quintet?
Yun, M. S.; Plana, H.; Iovino, A. +7 more
We present a multiwavelength study of the highly evolved compact galaxy group known as Seyfert's Sextet (HCG79: SS). We interpret SS as a 2-3 Gyr more evolved analog of Stephan's Quintet (HCG92: SQ). We postulate that SS formed by sequential acquisition of 4-5 primarily late-type field galaxies. Four of the five galaxies show an early-type morphol…
XMM-Newton Discovery of 217 s Pulsations in the Brightest Persistent Supersoft X-Ray Source in M31
Trudolyubov, Sergey P.; Priedhorsky, William C.
We report on the discovery of a periodic modulation in the bright supersoft X-ray source XMMU J004252.5+411540 detected in the 2000-2004 XMM-Newton observations of M31. The source exhibits X-ray pulsations with a period P ~ 217.7 s and a quasi-sinusoidal pulse shape and pulsed fraction ~7%-11%. We did not detect statistically significant changes i…
Intergalactic He II Absorption in the Spectra of Quasars at Redshifts 3.5 and 3.8, Observed with the HST ACS Prism
Anderson, Scott F.; Schneider, Donald P.; York, Donald G. +8 more
We present the UV spectra of two quasars obtained with the Hubble Space Telescope Advanced Camera for Surveys (HST ACS) prism (R ~ 100). One quasar, at redshift z = 3.5, shows an absorption edge consistent either with nearly fully ionized helium with an intergalactic He II Lyα optical depth at 304 Å of τ304 > 3.1 (90% confidence), or…
The Role of Transient Brightenings in Heating the Solar Corona
Warren, Harry P.; Ugarte-Urra, Ignacio; Brooks, David H.
Nanoflare reconnection events have been proposed as a mechanism for heating the corona. Parker's original suggestion was that frequent reconnection events occur in coronal loops due to the braiding of the magnetic field. Many observational studies, however, have focused on the properties of isolated transient brightenings unassociated with loops, …
Coupled rotational dynamics of Saturn's thermosphere and magnetosphere: a thermospheric modelling study
Smith, C. G. A.; Aylward, A. D.
We use a numerical model of Saturn's thermosphere to investigate the flow of angular momentum from the atmosphere to the magnetosphere. The thermosphere model is driven by Joule heating and ion drag calculated from a simple model of the magnetospheric plasma flows and a fixed model of the ionospheric conductivity. We describe an initial study in w…
Polar Plume Brightening During the 2006 March 29 Total Eclipse
Rušin, V.; Druckmüller, M.; Minarovjech, M. +8 more
We discuss a remarkable brightening in a polar plume, as inferred from unique coordinated observations of the white-light corona during the total eclipse of the Sun of 2006 March 29. The polar plume (also known as a polar ray, with distinctions that we discuss) was observed at the positional angle of 9° the velocity at which the brightening propag…
Spectroscopic Confirmation of the Fifth Image of SDSS J1004+4112 and Implications for the MBH--σ* Relation at z = 0.68
Smith, Graham P.; Oguri, Masamune; Sharon, Keren +5 more
We present the results of deep spectroscopy for the central region of the cluster lens SDSSJ 1004+4112 with the Subaru Telescope. A secure detection of an emission line of the faint blue stellar object (component E) near the center of the brightest cluster galaxy (G1) confirms that it is the central fifth image of the lensed quasar system. In addi…
Multispacecraft observation of electron beam in reconnection region
Escoubet, C. P.; Lavraud, B.; Fazakerley, A. N. +6 more
On the 18th of August 2002, during a crossing of the near-Earth plasma sheet Cluster observed an ion flow burst, caused by a near-Earth reconnection event. Cluster observed a tailward bulk flow which reverse to earthward flow, indicating a close passage of the diffusion region. We show that reversals in BZ and BY are consiste…
Multi-wavelength observations of a nearby multi-phase interstellar cloud
Boulanger, F.; Falgarone, E.; Le Bourlot, J. +3 more
Aims: High-resolution spectroscopic observations (UV HST/STIS and optical) are used to characterize the physical state and velocity structure of the multiphase interstellar medium seen towards the nearby (170 pc) star HD 102065. The star is located behind the tail of a cometary-shaped, infrared cirrus-cloud, in the area of interaction between the …
Hubble Space Telescope Search for M Subdwarf Binaries
Gizis, John E.; Riaz, Basmah; Samaddar, Debasmita
We present HST ACS observations of 19 nearby M subdwarfs in a search for binary systems. Other than the wide common proper-motion pair LHS 2140/2139, none of our sdM and esdM targets are found to be binaries. Our survey is sensitive to equal-luminosity companions at close (2-8 AU) separations, while substellar secondaries could have been detected …