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Constraining the Black Hole Mass and Accretion Rate in the Narrow-Line Seyfert 1 Galaxy RE J1034+396
Fiore, F.; Comastri, A.; Siemiginowska, A. +4 more
We present a comprehensive study of the spectrum of the narrow-line Seyfert 1 (NLS1) galaxy RE J1034+396, summarizing the information obtained from the optical to X-rays with observations from the William Herschel 4.2 m Telescope, the Hubble Space Telescope, the Extreme Ultraviolet Explorer, ROSAT, ASCA, and BeppoSAX. The BeppoSAX spectra reveal a…
Magnetic Power Spectra Derived from Ground and Space Measurements of the Solar Magnetic Fields
Yurchyshyn, V.; Wang, H.; Goode, P. R. +1 more
We study magnetic power spectra of active and quiet regions by using Big Bear Solar Observatory and SOHO/MDI measurements of longitudinal magnetic fields. The MDI power spectra were corrected with Gaussian Modulation Transfer Function. We obtained reliable magnetic power spectra in the high wave numbers range, up to k=4.6 Mm−1, which co…
A spectroscopic survey for lambda Bootis stars. III. Final results
Paunzen, E.
In the third paper of a series dedicated to the spectroscopic survey for new lambda Bootis stars, we present all new and confirmed members of the group as well as a detailed analysis of the observed sample. The nature of this small group of chemically peculiar stars of the upper main sequence still challenges our understanding of processes like di…
VLBI, MERLIN and HST observations of the giant radio galaxy 3C 236
Dallacasa, D.; Gurvits, L. I.; Miley, G. K. +6 more
We present VLBI and MERLIN data at 1.66 and 4.99 GHz on the central component coincident with the nucleus of the giant radio galaxy, 3C 236. The nuclear radio structure is composed of two complexes of emission which are resolved on scales from 1 milli-arcsec (mas) to 1 arcsec. Oscillations with an amplitude of ~ 5degr can be seen in the compact ra…
An Observational Manifestation of Magnetoatmospheric Waves in Internetwork Regions of the Chromosphere and Transition Region
Peter, H.; Judge, P. G.; Cally, P. S. +7 more
We discuss an observational signature of magnetoatmospheric waves in the chromosphere and transition region away from network magnetic fields. We demonstrate that when the observed quantity, line or continuum emission, is formed under high-β conditions, where β is the ratio of the plasma and magnetic pressures, we see fluctuations in intensity and…
Intermittent thermal plasma acceleration linked to sporadic motions of the magnetopause, first Cluster results
Lundin, R.; Sauvaud, J. -A.; Dandouras, I. +17 more
This paper presents the first observations with Cluster of a very dense population of thermal ionospheric ions (H+, He+, O+) locally "accelerated" perpendicularly to the local magnetic field in a region adjacent to the magnetopause and on its magnetospheric side. The observation periods follow a long period of very weak magnetic activity. Recurren…
Prediction in Real Time of the 2000 July 14 Heliospheric Shock Wave and its Companions During the `Bastille' Epoch*
Andrews, M. D.; Dryer, M.; Smith, Z. +4 more
Prediction of solar-generated disturbances and their three-dimensional propagation through interplanetary space continues to present a vitally important operational space weather forecasting objective. This paper presents the first successful real-time prediction of a series of major heliospheric shock waves at Earth, including the one from the 14…
The extended X-ray halo of the Crab-like SNR G21.5-0.9
Haberl, F.; Bernard, J. -P.; Read, A. M. +12 more
Recent XMM-Newton observations reveal an extended (r ~ 150'') low-surface brightness X-ray halo in the supernova remnant G21.5-0.9. The near circular symmetry, the lack of any limb brightening and the non-thermal spectral form, all favour an interpretation of this outer halo as an extension of the central synchrotron nebula rather than as a shell …
Monitoring of the optical and 2.5-11.7 mu m spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk 279 with ISO
Altieri, B.; Malkan, M. A.; Clavel, J. +29 more
Mid-infrared images of the Seyfert 1 galaxy
HST NICMOS photometry of the reddened bulge globular clusters NGC 6528, Terzan 5, Liller 1, UKS 1 and Terzan 4
Zoccali, M.; Rich, R. M.; Bica, E. +4 more
We present results from NICMOS Hubble Space Telescope observations of the reddened bulge globular clusters NGC 6528, Terzan 5, Liller 1, UKS 1 and Terzan 4, obtained through the filters F110W (1.1 mu m) and F160W (1.6 mu m) (nearly equivalent to J and H). For the first time the turnoff region of Liller 1 and the main sequence of Terzan 5 and Terza…