Search Publications
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…
Cluster and DMSP observations of SAID electric fields
Lucek, E.; Khotyaintsev, Y.; Kistler, L. +5 more
We report on magnetically conjugate Cluster and the Defense Meteorological Satellite Program (DMSP) satellite observations of subauroral ion drifts (SAID) during moderate geomagnetic activity levels on 8 April 2004. To our knowledge, the field-aligned separation of DMSP and Cluster (≈28,000 km) is the largest separation ever analyzed with respect …
Evolution of the Sheared Magnetic Fields of Two X-Class Flares Observed by Hinode/XRT
Golub, Leon; van Ballegooijen, Adriaan; Narukage, Noriyuki +6 more
We present multi-wavelength observations of the evolution of the sheared magnetic fields in NOAA Active Region 10930, where two X-class flares occurred on 2006 December 13 and December 14, respectively. Observations made with the X-ray Telescope (XRT) and the Solar Optical Telescope (SOT) aboard Hinode suggest that the gradual formation of the she…