Search Publications
Near-infrared imaging polarimetry of young stellar objects in ρ Ophiuchi
Gledhill, T. M.; Lucas, P. W.; Beckford, A. F. +1 more
The results of a near-infrared (J H K LP) imaging linear polarimetry survey of 20 young stellar objects (YSOs) in ρ Ophiuchi are presented. The majority of the sources are unresolved, with K-band polarizations, PK < 6 per cent. Several objects are associated with extended reflection nebulae. These objects have centrosymmet…
Evidence for metallicity spreads in three massive M 31 globular clusters
Jablonka, P.; Sarajedini, A.; Meylan, G. +3 more
Aims: We quantify the intrinsic width of the red giant branches of three massive globular clusters in M 31 in a search for metallicity spreads within these objects.
Methods: We present HST/ACS observations of three massive clusters in M 31, G78, G213, and G280. A thorough description of the photometry extraction and calibration is presented. A…
High-resolution Enceladus atlas derived from Cassini-ISS images
Scholten, F.; Matz, K. -D.; Neukum, G. +8 more
The Cassini Imaging Science Subsystem (ISS) acquired 377 high-resolution images (<1 km/pixel) during three close flybys of Enceladus in 2005 [Porco, C.C., et al., 2006. Cassini observes the active south pole of Enceladus. Science 311, 1393-1401.]. We combined these images with lower resolution Cassini images and four others taken by Voyager cam…
A reinterpretation of the energy balance in active region loops following new results from Hinode EIS
Bradshaw, S. J.
Context: New observations made by the Hinode EUV Imaging Spectrometer have revealed persistent redshifts in solar active region loops in the temperature range 105.6 ≤ T ≤ 106.4 K. The presence of redshifts, interpreted as bulk downflows, indicates that the loops are undergoing radiative cooling rather than continuous heating.…
Segmentation of extreme ultraviolet solar images via multichannel fuzzy clustering
Hochedez, Jean-François; Delouille, Véronique; Barra, Vincent
The study of the variability of the solar corona and the monitoring of its traditional regions (Coronal Holes, Quiet Sun and Active Regions) are of great importance in astrophysics as well as in view of the Space Weather and Space Climate applications. Here we propose a multichannel unsupervised spatially constrained fuzzy clustering algorithm tha…
Inverse Compton emission from the lobes of 3C353
Hardcastle, M. J.; Croston, J. H.; Perley, R. A. +2 more
X-ray emission due to inverse Compton scattering of microwave background photons by electrons in the lobes of powerful radio galaxies has now been seen in a large number of objects. Combining an inverse Compton model for the lobe X-ray emission with information obtained from radio synchrotron emission provides a method of constraining the electron…
The Plasma Structure of the Southwestern Region of the Cygnus Loop with the XMM-Newton Observatory
Katsuda, Satoru; Uchida, Hiroyuki; Tsunemi, Hiroshi +1 more
We observed the southwestern region of the Cygnus Loop in two pointings with XMM-Newton. The region observed is called the "blow-out" region, which is extended further in the south. The origin of the "blow out" is not well understood, but it is suggested that there is another supernova remnant here in radio observation. To investigate in detail th…
Parallel Motions of Coronal Hard X-Ray Source and Hα Ribbons
Gary, Dale E.; Lee, Jeongwoo
During solar flares Hα ribbons form and often move away from the local magnetic polarity inversion line (PIL). While the motion perpendicular to the PIL has been taken as evidence for coronal magnetic reconnection in the so-called CSHKP standard model, the other velocity component parallel to the PIL is much less adopted as a property of the magne…
Photochemical Enrichment of Deuterium in Titan's Atmosphere: New Insights from Cassini-Huygens
Mousis, Olivier; Lunine, Jonathan I.; Vuitton, Véronique +2 more
Cassini-Huygens data are used to reexamine the potential sources of the D/H enhancement over solar, measured in methane, in Titan's atmosphere. Assuming that the system is closed with respect to carbon, the use of constraints from the Huygens probe for the determination of the current mass of atmospheric methane and the most up-to-date determinati…
Perspectives in Global Helioseismology and the Road Ahead
Chaplin, William J.; Basu, Sarbani
We review the impact of global helioseismology on key questions concerning the internal structure and dynamics of the Sun and consider the exciting challenges the field faces as it enters a fourth decade of science exploitation. We do so with an eye on the past, looking at the perspectives global helioseismology offered in its earlier phases, in p…