Search Publications
Discovery of a high confidence soft lag from an X-ray flare of Markarian 421
Zhang, Peng; Shao, Li; Zhang, YouHong +1 more
We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a ∼60 ks long XMM-Newton observation performed on November 9–10, 2005. The source experienced a pronounced flare, of which the inter-band time lags were determined with a very high confidence level. The soft (0.6–0.8 keV) X-ray variations lagged the hard (4…
Beginning of the super-soft phase of the classical nova V2491 Cygni
Ness, J. -U.; Takei, D.
We present the results of soft X-ray studies of the classical nova V2491 Cygni using the Suzaku observatory. On day 29 after outburst, a soft X-ray component with a peak at ∼0.5 keV has appeared, which is tantalising evidence for the beginning of the super-soft X-ray emission phase. We show that an absorbed blackbody model can describe the observe…
Empirical Modeling of Radiative versus Magnetic Flux for the Sun-as-a-Star
Nandy, Dibyendu; Martens, Petrus C. H.; Preminger, Dora +1 more
We study the relationship between full-disk solar radiative flux at different wavelengths and average solar photospheric magnetic-flux density, using daily measurements from the Kitt Peak magnetograph and other instruments extending over one or more solar cycles. We use two different statistical methods to determine the underlying nature of these …
Suzaku Observations of the Supernova Remnant N23 in the Large Magellanic Cloud
Ishida, Manabu; Bamba, Aya; Someya, Kentaro
X-ray emission from the supernova remnant N23 in the Large Magellanic Cloud (LMC) has been studied using the X-ray Imaging Spectrometer (XIS) onboard Suzaku. Thanks to a superior energy resolution of the XIS in the soft X-ray band, we resolved H-like and He-like Oxygen K
XMM-NEWTON Observations of Three Low X-ray Luminosity Galaxy Clusters
Donahue, Megan; Voit, G. Mark; Conselice, Christopher J. +2 more
We present new XMM-Newton measurements of the X-ray luminosities (Lx ) and temperatures (Tx ) for three clusters of galaxies. Two are low Lx (<3 × 1043 erg s-1) clusters, RXJ0110.3+1938 (z = 0.317) and RXJ1011.0+5339 (z = 0.329). These clusters were selected from the 160 Square Degree Surve…
Comparative study of a substorm event by satellite observation and model simulation
Ridley, A. J.; Wang, Hui; Ma, ShuYing
A substorm event has been simulated for the first time by using SWMF (Space Weather Modeling Framework) developed by the University of Michigan. The model results have been validated using Geotail and Cluster satellite observations. The substorm onset occurs at 22:08 UT on September 28 2004, as identified from FUV WIC observations on the NASA IMAG…
CoRoT observations of the young open cluster Dolidze 25
Prada Moroni, P. G.; Degl'Innocenti, S.; Gandolfi, D. +27 more
We present some preliminary results based on the CoRoT observations of the young distant cluster Dolidze 25. The light curve for the 28 stars observed by the satellite have been analyzed and the relevant periodogram presented. As a result we have found two binary, three Pulsating Be, three SPB, two Spotted and one ellipsoidal variables. Noteworthy…
The Earth Orientation Catalog 4 . An optical reference frame for monitoring Earth's orientation in the 20th century
Vondrák, J.; Štefka, V.
Context. The astrometric ground-based observations of latitude/universal time variations, covering the interval 1899.7-2003.0, were used in combination with Hipparcos/Tycho positions and some older ground-based catalogs to construct a family of catalogs, tailored to long-term Earth-rotation studies. These catalogs, called Earth Orientation Catalog…
A Detailed Far-Ultraviolet Spectral Atlas of Main-Sequence B Stars
Smith, Myron A.
We have constructed a detailed spectral atlas covering the wavelength region 930-1225 Å for 10 sharp-lined B0-B9 stars near the main sequence. Most of the spectra we assembled are from the archives of the Far Ultraviolet Spectroscopic Explorer satellite, but for nine stars, wavelength coverage above 1188 Å was taken from high-resolution Internatio…
The dense and asymmetric central star wind of the young PN He 2-138
Prinja, R. K.; Urbaneja, M. A.; Massa, D. L. +1 more
We present optical European Southern Observatory time series and UV archival (Far Ultraviolet Spectroscopic Explorer (FUSE), Hubble Space Telescope, International Ultraviolet Explorer) spectroscopy of the H-rich central star of He 2-138. Our study targets the central star wind in a very young planetary nebula, and explores physical conditions that…