Search Publications
Flares, Magnetic Fields, and Subsurface Vorticity: A Survey of GONG and MDI Data
Howe, R.; Komm, R.; Hill, F. +3 more
We search for a relation between flows below active regions and flare events occurring in those active regions. For this purpose, we determine the subsurface flows from high-resolution Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) Dynamics Program data using the ring-diagram technique. We then calculate the vorticity o…
Automated analysis of eclipsing binary light curves - II. Statistical analysis of OGLE LMC eclipsing binaries
Mazeh, T.; North, P.; Tamuz, O.
In the first paper of this series, we presented EBAS - Eclipsing Binary Automated Solver, a new fully automated algorithm to analyse the light curves of eclipsing binaries, based on the EBOP code. Here, we apply the new algorithm to the whole sample of 2580 binaries found in the Optical Gravitational Lensing Experiment (OGLE) Large Magellanic Clou…
The Chandra, Hubble Space Telescope, and VLA View of the Circumnuclear Extended Emission in the Narrow Emission Line Galaxy NGC 2110
Gallagher, Sarah C.; Lee, Julia C.; Kraft, Ralph P. +4 more
We present results from new Chandra, archival Hubble Space Telescope (HST), and VLA imaging observations of the circumnuclear extended emission in the nearby Type 2 Seyfert galaxy NGC 2110. We find resolved soft-band X-ray emission ~4" (~160 pc) north of the nucleus, which is spatially coincident with [O III] emission, but lies just beyond the nor…
Multiwavelength XMM-Newton observations of the Laor et al. sample of PG quasars
Schady, P.; Mason, K. O.; Starling, R. L. C. +3 more
We present XMM-Newton/EPIC spectra for the Laor et al. sample of Palomar Green (PG) quasars. We find that a power law provides a reasonable fit to the 2-5 keV region of the spectra. Excess soft X-ray emission below 2 keV is present for all objects, with the exception of those known to contain a warm absorber. However, a single power law is a poor …
Suzaku observations of iron lines and reflection in AGN
Kataoka, J.; Fabian, A. C.; Takahashi, T. +8 more
Initial results on the iron K-shell line and reflection component in several AGN observed as part of the Suzaku Guaranteed Time program are reviewed. This paper discusses a small sample of Compton-thin Seyferts observed to date with Suzaku; namely MCG -5-23-16, MCG -6-30-15, NGC 4051, NGC 3516, NGC 2110, 3C 120 and NGC 2992. The broad iron K\alpha…
On the excitation of ULF waves by solar wind pressure enhancements
Glassmeier, K. -H.; Blomberg, L. G.; Schaefer, S. +1 more
We study the onset and development of an ultra low frequency (ULF) pulsation excited by a storm sudden commencement. On 30 August 2001, 14:10 UT, the Cluster spacecraft are located in the dayside magnetosphere and observe the excitation of a ULF pulsation by a threefold enhancement in the solar wind dynamic pressure. Two different harmonics are ob…
Multiwavelength Observations of EXO 0748-676. II. Emission-Line Behavior
O'Brien, K.; King, A. R.; Nelemans, G. +6 more
We present optical and ultraviolet spectra, light curves, and Doppler tomograms of the low-mass X-ray binary EXO 0748-676. Using an extensive set of 15 emission-line tomograms, we show that, along with the usual emission from the stream and ``hot spot,'' there is extended nonaxisymmetric emission from the disk rim. Some of the emission and Hα and …
Lensing Magnification of Supernovae in the GOODS Fields
Goobar, A.; Mörtsell, E.; Lee, K. +3 more
Gravitational lensing of high-redshift supernovae is potentially an important source of uncertainty when cosmological parameters are being derived from the measured brightness of Type Ia supernovae, especially in deep surveys with scarce statistics. Photometric and spectroscopic measurements of foreground galaxies along the lines of sight of 33 su…
An XMM-Newton survey of the Local Group galaxy M 33 - variability of the detected sources
Pietsch, W.; Haberl, F.; Hatzidimitriou, D. +3 more
We present an analysis of the individual observations of a deep XMM-Newton survey of the Local Group spiral galaxy M 33. We detected a total of 350 sources with fluxes (in the 0.2-4.5 keV energy band) in the range 6.7 × 10-16-1.5 × 10-11 erg s-1. This comprehensive study considers flux variability, spectral charact…
Pseudobulges in the Disk Galaxies NGC 7690 and NGC 4593
Kormendy, John; Knapen, Johan H.; Cornell, Mark E. +2 more
We present Ks-band surface photometry of NGC 7690 (Hubble type Sab) and NGC 4593 (SBb). We find that, in both galaxies, a major part of the ``bulge'' is as flat as the disk and has approximately the same color as the inner disk. In other words, the ``bulges'' of these galaxies have disklike properties. We conclude that these are example…