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Swift XRT Observation of 34 New INTEGRAL IBIS AGNs: Discovery of Compton-Thick and Other Peculiar Sources
Gehrels, N.; Bird, A. J.; Fiocchi, M. +7 more
For a significant number of the sources detected at high energies (>10 keV) by the INTEGRAL IBIS and Swift BAT instruments there is either a lack information about them in the 2-10 keV range or they are totally unidentified. Herein, we report on a sample of 34 IBIS AGNs or AGN candidate objects for which there is X-ray data in the Swift XRT arc…
Analysis of a giant lightning storm on Saturn
Gurnett, D. A.; Kurth, W. S.; Fischer, G. +5 more
On January 23, 2006, the Cassini/RPWS (Radio and Plasma Wave Science) instrument detected a massive outbreak of SEDs (Saturn Electrostatic Discharges). The following SED storm lasted for about one month and consisted of 71 consecutive episodes. It exceeded all other previous SED observations by Cassini as well as by the Voyagers with regard to num…
XMMU J174716.1-281048: a ``quasi-persistent'' very faint X-ray transient?
Mereghetti, S.; Sidoli, L.; Ubertini, P. +3 more
The X-ray transient XMMU J174716.1-281048 was serendipitously discovered with XMM-Newton in 2003. It lies about 0.9 degrees off the Galactic Centre and its spectrum shows a high absorption (~8× 1022 cm-2). Previous X-ray observations of the source field performed in 2000 and 2001 did not detect the source, indicative of a qui…
Gemini Spectroscopic Survey of Young Star Clusters in Merging/Interacting Galaxies. II. NGC 3256 Clusters
Schweizer, François; Miller, Bryan W.; Trancho, Gelys +1 more
We present Gemini optical spectroscopy of 23 young star clusters in NGC 3256. We find that the cluster ages range from few to ~150 Myr. All these clusters are relatively massive [(2-40)×105 Msolar] and appear to be of roughly 1.5 Zsolar metallicity. The majority of the clusters in our sample follow the same rotatio…
Layered mantling deposits in northeast Arabia Terra, Mars: Noachian-Hesperian sedimentation, erosion, and terrain inversion
Head, James W.; Fassett, Caleb I.
Thick, layered mantling deposits of different ages occur in several nonpolar regions of Mars and are thought to represent volcanic ash and/or climate-related ice-dust deposition. One such deposit is a layered mantling unit that unconformably blanketed highlands terrain in northeast Arabia Terra during the Late Noachian and/or earliest Hesperian. S…
The Surprising External Upturn of the Blue Straggler Radial Distribution in M55
Dalessandro, E.; Ferraro, F. R.; Lanzoni, B. +3 more
By combining high-resolution HST and wide-field ground-based observations in ultraviolet and optical bands, we study the blue straggler star (BSS) population of the low-density galactic globular cluster M55 (NGC 6809) over its entire radial extent. The BSS projected radial distribution is found to be bimodal, with a central peak, a broad minimum a…
On the Characteristics of the Solar Gravity Mode Frequencies
García, R. A.; Mathur, S.; Turck-Chièze, S. +1 more
Gravity modes are the best probes for studying the dynamics of the solar radiative zone, and especially the nuclear core. This paper shows how specific physical processes influence the theoretical g-mode frequencies for the l=1 and l=2 modes over a large range of radial orders n from -46 to -1, corresponding to potential SOHO observations. To this…
SDSS J160531.84+174826.1: A Dwarf Disk Galaxy with an Intermediate-Mass Black Hole
Yuan, Weimin; Zhou, Hongyan; Wang, Huiyuan +7 more
We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate intermediate-mass black hole, hosted by the dwarf galaxy SDSS J160531.84+174826.1 at z=0.032. A broad component of the Hα line with FWHM=781 km s-1 is detected in its optical spectrum, and a bright, pointlike nucleus is evident from a Hubble Spac…
VLT and ACS Observations of RDCS J1252.9-2927: Dynamical Structure and Galaxy Populations in a Massive Cluster at z = 1.237
Ford, H. C.; Demarco, R.; Infante, L. +26 more
We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22<z<1.…
Velocity Structure of Jets in a Coronal Hole
Shibata, Kazunari; Warren, Harry P.; Hara, Hirohisa +4 more
The velocity structures of jets in a coronal hole have been derived for the first time. Hinode observations revealed the existence of many bright points in coronal holes. They are loop-shaped and sometimes associated with coronal jets. Spectra obtained with the Extreme-ultraviolet Imaging Spectrometer aboard Hinode were analyzed to infer the Doppl…