Search Publications
X-ray to UV variability correlation in MCG-6-30-15
Papadakis, I.; Arévalo, P.; Kuhlbrodt, B. +1 more
We used a ∼ 300 ks long XMM-Newton observation of the Seyfert 1 galaxy MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 ÅU bands. We found a significant correlation peak at a time lag of τmax ∼ 160 ks where the UV flux variations preceded the variations in the X-ray band. We interpret this result as ev…
X-ray tomography of a cometary bow shock
Dennerl, K.; Wegmann, R.
The volume intensity of the cometary X-ray emission is enhanced behind the bow shock by a factor of up to three. This effect offers the opportunity to identify the bow shock by a tomographic method in X-ray images of comets. By an analysis of the X-ray data obtained by XMM-Newton from Comet C/2000 WM1 (LINEAR) we obtain information on the position…
A changing inner radius in the accretion disc of Q0056-363?
Maiolino, R.; Bianchi, S.; Falocco, S. +4 more
Q0056-363 is the most powerful X-ray quasar known to exhibit a broad, likely relativistic iron line (Porquet & Reeves 2003, A&A, 408, 119). It has been observed twice by XMM-Newton, three and half years apart (July 2000 and December 2003). In the second observation, the UV and soft X-ray fluxes were fainter, the hard X-ray power law flatte…
Recovering Solar Toroidal Field Dynamics from Sunspot Location Patterns
Norton, Aimee A.; Gilman, Peter A.
We analyze both Kitt Peak magnetogram data and MDI continuum intensity sunspot data to search for the following solar toroidal band properties: width in latitude and the existence of a tipping instability (longitudinal m=1 mode) for any time during the solar cycle. In order to determine the extent to which we can recover the toroidal field dynamic…
Solar Wind Outflow in Polar Plumes from 1.05 to 2.4 Rsolar
Llebaria, A.; Abbo, L.; Antonucci, E. +2 more
An earlier publication (Paper I), which measured the outflow velocity in solar plumes out to 1.35 Rsolar using the Doppler dimming technique, has here been extended out to 2.4 Rsolar by including observations from SOHO UVCS. It is shown that plume outflow velocities, greater than interplumes at lower heights, have lower accel…
X-Ray Emission and Optical Polarization of V1432 Aquilae: An Asynchronous Polar
Singh, K. P.; Buckley, D. A. H.; Rana, V. R. +1 more
A detailed analysis of X-ray data obtained with ROSAT, ASCA, XMM-Newton, and the Rossi X-ray Timing Explorer (RXTE) for the asynchronous polar V1432 Aquilae is presented. An analysis of Stokes polarimetry data obtained from the South African Astronomical Observatory (SAAO) is also presented. Power spectra from long-baseline ROSAT data show a spin …
A Survey of Analogs to Weak Mg II Absorbers in the Present
Charlton, Jane C.; Narayanan, Anand; Lynch, Ryan +1 more
We present the results of a survey of the analogs of weak Mg II absorbers [rest-frame equivalent width Wr(2796)<0.3 Å] at 0<z<0.3. Our sample consisted of 25 HST STIS echelle quasar spectra (R=45,000), which covered Si II λ1260 and C II λ1335 over this redshift range. Using those similar transitions as tracers of Mg II facilita…
Integral Field Spectroscopy of 23 Spiral Bulges
Marconi, A.; Capetti, A.; Scarlata, C. +7 more
We have obtained integral-field spectroscopy for 23 spiral bulges using INTEGRAL on the William Herschel Telescope and SPIRAL on the Anglo-Australian Telescope. This is the first two-dimensional survey directed solely at the bulges of spiral galaxies. Eleven galaxies of the sample do not have previous measurements of the stellar velocity dispersio…
Multiwavelength Analysis of a Solar Flare on 2002 April 15
White, Stephen M.; Zhang, Jie; Holman, Gordon D. +1 more
We carried out a multiwavelength analysis of the solar limb flare on 2002 April 15. The observations all indicate that the flare occurred in an active region with an asymmetric dipole magnetic configuration. The earlier conclusion that magnetic reconnection is occurring in a large-scale current sheet in this flare is further supported by these obs…
V453 Oph: a s-process enriched, but carbon-deficient RV Tauri star of low intrinsic metallicity
van Winckel, H.; Siess, L.; Goriely, S. +2 more
This paper reports the detection of a heavy element enriched RV Tauri variable with an abundance pattern that differs significantly from a standard s-process enriched object: