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Interaction of magnetic field systems leading to an X1.7 flare due to large-scale flux tube emergence
Bommier, V.; Schmieder, B.; Li, H. +1 more
Aims:The aim of this paper is to understand the magnetic configuration and evolution of an active region, which permitted an X1.7 flare to be observed during the decaying phase of a long-duration X1.5 flare on 2005 September 13.
Methods: We performed a multi-wavelength analysis using data from space-borne (Solar and Heliospheric Observatory (S…
IGR J08408-4503: A New Recurrent Supergiant Fast X-Ray Transient
Götz, D.; von Kienlin, A.; De Luca, A. +3 more
The supergiant fast X-ray transient IGR J08408-4503 was discovered by INTEGRAL on 2006 May 15 during a bright flare. The source shows sporadic recurrent short bright flares, reaching a peak luminosity of 1036 ergs s-1 within less than 1 hr. The companion star is HD 74194, an Ob5Ib(f) supergiant star located at 3 kpc in the Ve…
Width of Radio-Loud and Radio-Quiet CMEs
Gopalswamy, N.; Michalek, G.; Xie, H.
In the present paper we report on the difference in angular sizes between radio-loud and radio-quiet CMEs. For this purpose we compiled these two samples of events using Wind/WAVES and SOHO/LASCO observations obtained during 1996 - 2005. We show that the radio-loud CMEs are almost twice as wide as the radio-quiet CMEs (considering expanding parts …
The velocity structure of moving magnetic feature pairs around sunspots: support for the U-loop model
Woch, J.; Solanki, S. K.; Zhang, J. +1 more
Context: Moving magnetic feature (MMF) pairs are among the most significant fine-scale structures around sunspots. Several models have been proposed to interpret the origin and evolution of MMF pairs. These models provide important clues to understanding MMF pairs.
Aims: We present an analysis of the velocity structure of MMF pairs in order to…
Optical colours of AGN in the extended Chandra deep field South: obscured black holes in early type galaxies
Georgantopoulos, I.; Rovilos, E.
We investigate the optical colours of X-ray sources from the Extended Chandra Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to explore AGN - galaxy feedback models. The X-ray sources populate both the “blue” and the “red sequence” on the colour-magnitude diagram. However, sources in the “red sequence” appear systematic…
Rosetta Asteroid Targets: 2867 Steins and 21 Lutetia
Barucci, M. A.; Rossi, A.; Fulchignoni, M.
In preparation for the flyby of the Rosetta spacecraft, the state of the knowledge of 21 Lutetia and 2867 Steins obtained by ground based observations is reported. Preliminary determination of shape and/or size, rotational properties and taxonomic types are presented for both asteroids. The dusty environment of the targets has been studied in orde…
Cool Customers in the Stellar Graveyard. IV. Spitzer Search for Mid-IR excesses Around Five DAs
Debes, John H.; Sigurdsson, Steinn; Hansen, Brad
Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, require external accretion of material to explain the presence of weak metal-line absorption in their photospheres. The source of this material is currently unknown, but could come from the interstellar medium, unseen companions, or relic planetesimals from asteroid belt or Kuiper …
An Update on the X-Ray Transient Narrow-Line Seyfert 1 Galaxy WPVS 007: Swift Observations of UV Variability and Persistence of X-Ray Faintness
O'Brien, Paul T.; Schady, Patricia; Leighly, Karen M. +3 more
We report on the detection of UV variability and the persistence of X-ray faintness of the X-ray transient narrow-line Seyfert 1 galaxy WPVS 007 based on the first year of monitoring with Swift between 2005 October and 2007 January. WPVS 007 has been an unusual source. Although it was X-ray-bright in the ROSAT All-Sky Survey, it has been extremely…
0.5 Mpc-scale extended X-ray emission in the z = 2.48 radio galaxy 4C 23.56
Dunlop, J.; Almaini, O.; Best, P. N. +1 more
We present an XMM-Newton observation of the radio galaxy 4C 23.56 at z = 2.48 which reveals extended X-ray emission coincident with the radio lobes spanning ~0.5 Mpc. These are the largest X-ray-bright lobes known at z > 2. Under the assumption that these features result from inverse-Compton scattering of cosmic microwave background photons by …
The Effects of Polarization Crosstalk and Solar Rotation on Measuring Full-Disk Solar Photospheric Vector Magnetic Fields
Zhang, H. Q.; Su, J. T.
Observations of full-disk solar photospheric vector magnetic fields are very important for the studies of the global properties and evolution of solar magnetism. Such observations can allow us to investigate the magnetic connectivities between active regions and the nonpotentiality of magnetic fields with a much wider field of view (FOV) than do l…