Zobrazeno 1 - 10
of 25
pro vyhledávání: '"W. F. Welsh"'
Publikováno v:
The Astronomical Journal. 127:481-488
We measured the I-band orbital light curve of the soft X-ray transient GS 2000+25 in 1992 August, and the R- and I-band light curves between 1998 September and 2000 August. The light curves are dominated by the ellipsoidal variations of the secondary
Publikováno v:
The Astrophysical Journal. 565:1169-1182
We obtained high dispersion spectra of CI Cam, the optical counterpart of XTE J0421+560, two weeks after the peak of its short outburst in 1998 April. The optical counterpart is a supergiant B[e] star emitting a two-component wind. The cool wind (the
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 312:70-82
We present spectra in the range 8000–8665 A of the close, detached M-dwarf–white-dwarf binaries EG UMa and PG 1026+002. The Na i absorption doublet (8183, 8195 A) is detected along with a number of other absorption lines including intrinsically n
Analysis of the oscillations in HST observations of the quiescent SU UMa type dwarf nova WZ Sagittae
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 310:750-758
ABSTRA C T An analysis of the UV oscillations in WZ Sge is presented, in which we obtain the oscillation amplitude spectra. We find a strong 27.9-s oscillation in our Hubble Space Telescope (HST) UV and zeroth-order light curves as well as weaker osc
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 310:398-406
We present results from photometric observations of the dwarf nova system HT Cas during the eruption of November 1995. The data include the first two--colour observations of an eclipse on the rise to outburst. They show that during the rise to outbur
Publikováno v:
The Astrophysical Journal. 509:118-131
The Faint Object Spectrograph on the Hubble Space Telescope (HST ) was used to obtain spectro- photometric observations of the Seyfert 1 galaxy NGC 7469. The spectra were obtained with a 90 s time resolution in order to resolve the fastest expected v
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 298:285-302
We present high-speed spectrophotometric observations of the Hα emission in the exotic cataclysmic variable AE Aqr. Over 10 000 spectra with a sampling rate of ∼ 6 s were obtained. The well-known 16.5- and 33-s oscillations were not detected in ei
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 291:L57-L61
Autor:
D. Dultzin-Hacyan, Thomas R. Ayres, Luis C. Ho, Richard W. Pogge, J. M. Rodriguez‐Espinoza, Gordon M. MacAlpine, D. M. Crenshaw, M. Mignoli, Alla I. Shapovalova, P. T. O'Brien, FZ Cheng, Keith Horne, K. Nandra, Steve Penton, J. M. Shull, Stephanie A. Snedden, M. R. Goad, Linda S. Sparke, Ari Laor, Julian H. Krolik, Brian R. Espey, Ian M. George, Alexei V. Filippenko, W. F. Welsh, T. J. Turner, Z.-L. Zou, Tal Alexander, Hagai Netzer, Shai Kaspi, N. G. Bochkarev, M. Dietrich, Danielle Alloin, M. H. Ulrich, M. A. Malkan, Kirk T. Korista, Maria Santos-Lleo, G. M. Stirpe, K. S. J. Anderson, C. Wei, Bradley M. Peterson, Tinggui Wang, Ignaz Wanders, Wolfram Kollatschny, Erika Benítez, Simon L. Morris, Andrea Comastri, Wei-Hsin Sun, Alexander N. Burenkov, Gerard A. Kriss, J. Clavel, Gail A. Reichert, Roger Ptak, SJ Xue, Stefan Collier, C. M. Gaskell, Willem Wamsteker, P. M. Rodríguez-Pascual
Publikováno v:
The Astrophysical Journal Supplement Series. 113:69-88
PUBLISHED
From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored the Seyfert 1 galaxy NGC 7469 continuously in an attempt to measure time delays between the continuum and emission-line fluxes. From the time delays, one ca
From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored the Seyfert 1 galaxy NGC 7469 continuously in an attempt to measure time delays between the continuum and emission-line fluxes. From the time delays, one ca
Publikováno v:
International Astronomical Union Colloquium. 158:29-32
Flickering is a poorly understood phenomenon associated with accretion processes, but this does not suffice to make it interesting. Why then should we bother studying this ‘noise’? Three reasons come to mind: (i) flickering is a fundamental signa