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The Interaction between Radio Lobes and Hot Gas in the Nearby Radio Galaxies 3C 285 and 3C 442A
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +4 more
We present Chandra observations of two nearby radio galaxies in group environments, 3C 285 and 3C 442A. The host galaxies of both sources are involved in mergers with nearby massive galaxies, and the hot gas in the systems is extended along lines joining the interacting galaxies. Both sources show strong evidence for interactions between the radio…
Precision Masses of the Low-Mass Binary System GJ 623
Ireland, Michael J.; Martinache, Frantz; Lloyd, James P. +2 more
We have used aperture masking interferometry and adaptive optics (AO) at the Palomar 200 inch telescope to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 yr combined with a decade of radial velocity measurements constrain all orbital parameters of the GJ 623 binary system accurately enough to criticall…
A Note on Saturation Seen in the MDI/SOHO Magnetograms
Liu, Y.; Scherrer, P. H.; Norton, A. A.
A type of saturation is sometimes seen in sunspot umbrae in MDI/SOHO magnetograms. In this paper, we present the underlying cause of such saturation. By using a set of MDI circular polarization filtergrams taken during an MDI line profile campaign observation, we derive the MDI magnetograms using two different approaches: the on-board data process…
Periodic microstructure in Saturn's rings A and B
French, Richard G.; Tyler, G. Leonard; Marouf, Essam A. +2 more
Diffraction of coherent radio waves transmitted by the Cassini spacecraft at 0.94- and 3.6-cm wavelengths indicates the presence of fine-scale structure in Saturn's rings A and B, characterized by a periodic radial variation in optical depth. Interpretation of the observed spectral signature in terms of a simple diffraction grating model yields es…
Suzaku Observation of Two Ultraluminous X-Ray Sources in NGC 1313
Done, Chris; Isobe, Naoki; Petre, Robert +19 more
Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313, named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the observation for a net exposure of 28 ks (but over a gross time span of 90ks), both objects varied in intensity by about 50%. The 0.4-10keV X-ray luminosities of X-1 and X-2 were measured as 2.5 × 10…
Evidence for late Hesperian lacustrine activity in Shalbatana Vallis, Mars
Reiss, Dennis; Di Achille, Gaetano; Ori, Gian Gabriele
An intravalley paleolake (more than 400 m deep) was detected along the course of Shalbatana Vallis from the evidence of shorelines and the occurrence of a few fan-delta deposits (including a Gilbert-type delta). The fronts of all the sedimentary deposits strikingly match the same topographic contours (2800 and 3000 m below the Martian datum), indi…
Fine Thermal Structure of a Coronal Active Region
Golub, Leon; Reale, Fabio; Shimojo, Masumi +9 more
The determination of the fine thermal structure of the solar corona is fundamental to constraining the coronal heating mechanisms. The Hinode X-ray Telescope collected images of the solar corona in different passbands, thus providing temperature diagnostics through energy ratios. By combining different filters to optimize the signal-to-noise ratio…
Morphologies and stellar populations of galaxies in the core of Abell 2218
Covone, G.; Sánchez, S. F.; Cardiel, N. +2 more
We present a study of the stellar populations and morphologies of galaxies in the core of the galaxy cluster Abell 2218. Integral field spectroscopy (IFS) observations were performed using PMAS in the PPAK mode covering a field of view of ~74 × 64 arcsec2 centred on the core of the cluster, in order to obtain spectroscopy of an unbiased…
Discovery of a new M 32-like "Compact Elliptical" galaxy in the halo of the Abell 496 cD galaxy
Chilingarian, I.; Adami, C.; Chemin, L. +4 more
Aims:"Compact ellipticals" are so rare that a search for M 32 analogs is needed to ensure the very existence of this class.
Methods: We report here the discovery of A496cE, a M 32 twin in the cluster Abell 496, located in the halo of the central cD.
Results: Based on CFHT and HST imaging we show that the light profile of A496cE requires a …
Formation and disruption of aquifers in southwestern Chryse Planitia, Mars
Komatsu, Goro; Fairén, Alberto G.; Kargel, Jeffrey S. +7 more
We present geologic evidence suggesting that after the development of Mars' cryolithosphere, the formation of aquifers in southwestern Chryse Planitia and their subsequent disruption led to extensive regional resurfacing during the Late Hesperian, and perhaps even during the Amazonian. In our model, these aquifers formed preferentially along thrus…