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HS 2331+3905: The cataclysmic variable that has it all
Gänsicke, B. T.; Marsh, T. R.; Hagen, H. -J. +6 more
We report detailed follow-up observations of the cataclysmic variable HS 2331+3905, identified as an emission-line object in the Hamburg Quasar Survey. An orbital period of 81.08 min is unambiguously determined from the detection of eclipses in the light curves of HS 2331+3905. A second photometric period is consistently detected at P ≃ 83.38 min,…
The progenitor of SN 2005cs in the Whirlpool Galaxy
Smartt, Stephen J.; Maund, Justyn R.; Danziger, I. John
The progenitor of SN 2005cs, in the galaxy M51, is identified in pre-explosion Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) imaging. Differential astrometry, with post-explosion ACS High Resolution Channel (HRC) F555W images, permitted the identification of the progenitor with an accuracy of 0.006 arcsec.…
Relationship between Magnetic Power Spectrum and Flare Productivity in Solar Active Regions
Abramenko, V. I.
Power spectra of the line-of-sight magnetograms were calculated for 16 active regions of different flare activity. Data obtained by the Michelson Doppler Imager instrument on board the Solar and Heliospheric Observatory in high-resolution mode were used in this study. For each active region, the daily soft X-ray flare index, A, was calculated. Thi…
Simultaneous Chandra X ray, Hubble Space Telescope ultraviolet, and Ulysses radio observations of Jupiter's aurora
MacDowall, R. J.; Waite, J. H.; Cravens, T. E. +8 more
Observations of Jupiter carried out by the Chandra Advanced CCD Imaging Spectrometer (ACIS-S) instrument over 24-26 February 2003 show that the auroral X-ray spectrum consists of line emission consistent with high-charge states of precipitating ions, and not a continuum as might be expected from bremsstrahlung. The part of the spectrum due to oxyg…
XMM-Newton spectroscopy of high-redshift quasars
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
XMM-Newton observations of 29 high-redshift (z > 2) quasars, including seven radio-quiet, 16 radio-loud and six broad absorption line (BAL) objects, are presented; due to the high redshifts, the rest-frame energy bands extend up to ~30-70 keV. Over 2-10 keV, the quasars can be well fitted in each case by a simple power law, with no strong evide…
The Discrepancy between Solar Abundances and Helioseismology
Basu, Sarbani; Antia, H. M.
There have been recent downward revisions of the solar photospheric abundances of oxygen and other heavy elements. These revised abundances along with OPAL opacities are not consistent with seismic constraints. In this work we show that the recently released Opacity Project opacity tables cannot resolve this discrepancy either. While the revision …
UVBLUE: A New High-Resolution Theoretical Library of Ultraviolet Stellar Spectra
Chavez, M.; Rodríguez-Merino, L. H.; Buzzoni, A. +1 more
We present an extended ultraviolet-blue (850-4700 Å) library of theoretical stellar spectral energy distributions computed at high resolution, λ/Δλ=50,000. The UVBLUE grid, as we named the library, is based on LTE calculations carried out with ATLAS9 and SYNTHE codes developed by R. L. Kurucz and consists of nearly 1800 entries that cover a large …
EDisCS - the ESO distant cluster survey. Sample definition and optical photometry
Pelló, R.; White, S. D. M.; Bremer, M. +23 more
We present the ESO Distant Cluster Survey (EDisCS), a survey of 20 fields containing distant galaxy clusters with redshifts ranging from 0.4 to almost 1.0. Candidate clusters were chosen from among the brightest objects identified in the Las Campanas Distant Cluster Survey, half with estimated redshift z_est∼0.5 and half with z_est∼0.8. They were …
The Nonpotentiality of Active-Region Coronae and the Dynamics of the Photospheric Magnetic Field
Title, Alan M.; Schrijver, Carolus J.; Metcalf, Thomas R. +1 more
The magnetic field in the solar photosphere frequently carries strong electric currents, even though the global coronal configuration often resembles a potential field ringed by the heliospheric current sheet. To understand this, we compare TRACE EUV images of active-region coronae and potential-field source-surface extrapolations based on SOHO MD…
Disentangling the composite continuum of symbiotic binaries. I. S-type systems
Skopal, A.
We describe a method of disentangling the composite, 0.12-5 µm continuum of symbiotic binaries. The observed SED is determined by the IUE/HST archival spectra and flux-points corresponding to the optical UBVRI and infrared JHKLM photometric measurements. The modeled SED is given by superposition of fluxes from the cool giant, hot stellar sou…