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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…
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…
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.…
Spitzer Identifications and Classifications of Submillimeter Galaxies in Giant, High-Redshift, Lyα-Emission-Line Nebulae
Ivison, R. J.; Smail, Ian; Alexander, D. M. +4 more
Using Spitzer Space Telescope IRAC (3.6-8 µm) and MIPS (24 µm) imaging, as well as Hubble Space Telescope optical observations, we identify the IRAC counterparts of the luminous power sources residing within the two largest and brightest Lyα-emitting nebulae (LABs) in the SA 22 protocluster at z=3.09 (LAB 1 and LAB 2). These sources ar…
Intense Star Formation and Feedback at High Redshift: Spatially Resolved Properties of the z = 2.6 Submillimeter Galaxy SMM J14011+0252
Lutz, D.; Genzel, R.; Baker, A. J. +9 more
We present a detailed analysis of the spatially resolved properties of the lensed submillimeter galaxy (SMG) SMM J14011+0252 at z=2.56, combining deep near-infrared integral-field data obtained with SPIFFI on the VLT with other multiwavelength data sets. As previously discussed by other authors, the broad characteristics of SMM J14011+0252 in part…
On the Variation of the Peak Asymmetry of Low-l Solar p Modes
Howe, R.; Jiménez-Reyes, S. J.; García, R. A. +4 more
The resonant peaks of solar p modes show small amounts of asymmetry in frequency. Here, we use five independent sets of contemporaneous data, collected over a ~=8 yr period, to investigate whether peak asymmetry in low angular degree p modes changes over the solar activity cycle. Three of the data sets are from instruments on board the ESA/NASA SO…
Searching for Earth Analogs Around the Nearest Stars: The Disk Age-Metallicity Relation and the Age Distribution in the Solar Neighborhood
Valenti, Jeff A.; Reid, I. Neill; Turnbull, Margaret C. +2 more
The chemical composition of Earth's atmosphere has undergone substantial evolution over the course of its history. It is possible, even likely, that terrestrial planets in other planetary systems have undergone similar changes; consequently, the age distribution of nearby stars is an important consideration in designing surveys for Earth analogs. …