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Double Nucleus in M83
Díaz, Rubén J.; Mast, Damián; Agüero, M. Paz
M83 is one of the nearest galaxies with enhanced nuclear star formation, and it presents one of the best opportunities to study the kinematics and physical properties of a circumnuclear starburst. Our three-dimensional spectroscopy data in the R band confirm the presence of a secondary nucleus or mass concentration (previously suggested by Thatte …
Swift XRT Follow-up Observations of TeV Sources of the HESS Inner Galaxy Survey
Masetti, N.; Bird, A. J.; Ubertini, P. +6 more
In order to provide a firm identification of the newly discovered Galactic TeV sources, a search for counterparts in a broad band from soft X-ray to soft gamma rays is crucial as data in these wave bands allow us to distinguish between different types of suggested models (for example, leptonic vs. hadronic) and, in turn, to disentangle their natur…
X-ray spectral properties of high-redshift radio-loud quasars beyond redshift 4 - first results*
Fabian, A. C.; Worsley, M. A.; Yuan, W. +1 more
We present the results of X-ray spectroscopic observations with XMM-Newton for four high-redshift radio-loud quasars at z > 4. Among these, three objects, namely GBB1508+5714, PMNJ0324-2918 and PKSB1251-407, do not show soft X-ray spectral flattening; the derived upper limits on assumed intrinsic absorption are (3.3-17.3) × 1021cm
Clues to Active Galactic Nucleus Growth from Optically Variable Objects in the Hubble Ultra Deep Field
Koekemoer, A. M.; Mobasher, B.; Hathi, N. P. +9 more
We present a photometric search for objects with point-source components that are optically variable on timescales of weeks to months in the Hubble Ultra Deep Field (HUDF) to i'AB=28.0 mag. The data are split into four substacks of approximately equal exposure times. Objects exhibiting the signature of optical variability are…
Supergranule Superrotation Identified as a Projection Effect
Hathaway, D. H.; Cuntz, M.; Williams, P. E.
Previous measurements of the rotation rate of the supergranule Doppler velocity pattern revealed surprising characteristics: (1) the pattern rotates faster than the plasma at the surface, and, at each latitude, it rotates faster than the plasma at any level below the surface (superrotation), (2) larger cells rotate more rapidly than smaller cells,…
Europa's FUV auroral tail on Jupiter
Clarke, J. T.; Mauk, B. H.; Gérard, J. -C. +3 more
Ultraviolet images of Jupiter's northern aurora obtained in 2005 confirm the existence of an electromagnetic interaction between Europa and the Jovian ionosphere. The auroral signature shows a two-component structure: a quasi-circular Europa spot, followed by a previously undetected faint tail emission trailing in the direction of corotation flow.…
Hubble Space Telescope NICMOS Polarization Measurements of OMC-1
Schultz, A. S. B.; Colgan, Sean W. J.; Burton, Michael G. +2 more
We present 2 µm polarization measurements of positions in the IRc2 and BN regions of the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2" resolution) on the Hubble Space Telescope. Our results are as follows: BN is ~29% polarized by dichroic absorption and appears to be the illuminating source for most of the nebulosity to its n…
Dust and cloud detection at the Mars limb with UV scattered sunlight with SPICAM
Montmessin, F.; Korablev, O.; Bertaux, J. -L. +3 more
The UV detector of Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) on board Mars Express has measured several profiles of light scattered at the limb of Mars. In this paper we present 33 profiles taken between January 2004 and August 2005. Scattering of UV light at the limb of Mars is due to the molecul…
Spatially Resolved Narrow-Line Region Kinematics in Active Galactic Nuclei
Shields, Joseph C.; Greene, Jenny E.; Pogge, Richard W. +4 more
We have analyzed Hubble Space Telescope spectroscopy of 24 nearby active galactic nuclei (AGNs) to investigate spatially resolved gas kinematics in the narrow-line region (NLR). These observations effectively isolate the nuclear line profiles on less than 100 pc scales and are used to investigate the origin of the substantial scatter between the w…
The Properties and Redshift Evolution of Intermediate-Luminosity Off-Nuclear X-Ray Sources in the Chandra Deep Fields
Lehmer, B. D.; Hornschemeier, A. E.; Alexander, D. M. +5 more
We analyze a population of intermediate-redshift (z~0.05-0.3) off-nuclear X-ray sources located within optically bright galaxies in the Great Observatories Origins Deep Survey and Galaxy Evolution from Morphology and SEDs fields. A total of 24 off-nuclear source candidates are classified using deep Chandra X-Ray Observatory exposures from the Chan…