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RR Lyrae stars in the southern globular cluster NGC 362
Derekas, A.; Kiss, L. L.; Csák, B. +3 more
Aims:NGC 362 is a bright southern globular cluster in the foreground of the Small Magellanic Cloud (SMC), for which no extensive variability survey has ever been done. Finding regularly pulsating RR Lyrae stars in the cluster can lead to improved metallicity and distance estimates of the system, while other types of variable objects may be used to…
Wind-wind collision in the η Carinae binary system - III. The HeII λ4686 line profile
Falceta-Gonçalves, D.; Abraham, Z.
We modelled the HeII λ4686 line profiles observed in the η Carinae binary system close to the 2003.5 spectroscopic event, assuming that they were formed in the shocked gas that flows at both sides of the contact surface formed by wind-wind collision. We used a constant flow velocity and added turbulence in the form of a Gaussian velocity distribut…
Structure detection in the D1 CFHTLS deep field using accurate photometric redshifts: a benchmark
Valtchanov, I.; Ilbert, O.; Pierre, M. +9 more
Aims:We investigate structures in the D1 CFHTLS deep field to test the method that will be applied to generate homogeneous samples of clusters and groups of galaxies in order to constrain the cosmology and detailed physics of groups and clusters.
Methods: An adaptive kernel technique was applied to galaxy catalogues. This technique needs none …
H-R Diagrams Based on the HD Stars in the Michigan Spectral Catalogue and the Hipparcos Catalog
Sowell, J. R.; Trippe, M.; Caballero-Nieves, S. M. +1 more
The systematic, spectroscopic two-dimensional classification of the HD stars by N. H. is approximately three-quarters complete. Over 161,000 stars have been classified visually using 10° objective-prism plates (2 Å resolution) taken at CTIO with the Michigan Curtis Schmidt telescope. The published portion of this large, homogeneous database, taken…
Semiregular variables in the solar neighbourhood
Glass, I. S.; van Leeuwen, F.
Period-luminosity sequences have been shown to exist among the semiregular variables (SRVs) in the Magellanic Clouds, the bulge of the Milky Way galaxy and elsewhere. Using modern-period and revised Hipparcos parallax data, this paper demonstrates that they also appear among the M giant SRVs of the solar neighbourhood. Their distribution in the K,…
2003-2005 INTEGRAL and XMM-Newton observations of 3C 273
Walter, R.; Page, K. L.; Staubert, R. +9 more
Aims:The aim of this paper is to study the evolution of the broadband spectrum of one of the brightest and nearest quasars 3C 273.
Methods: We analyze the data obtained during quasi-simultaneous INTEGRAL and XMM-Newton monitoring of the blazar 3C 273 in 2003-2005 in the UV, X-ray and soft γ-ray bands and study the results in the context of the…
Parametric instabilities of parallel propagating incoherent Alfvén waves in a finite ion beta plasma
Nariyuki, Y.; Hada, T.; Tsubouchi, K.
Large amplitude, low-frequency Alfvén waves constitute one of the most essential elements of magnetohydrodynamic (MHD) turbulence in the fast solar wind. Due to small collisionless dissipation rates, the waves can propagate long distances and efficiently convey such macroscopic quantities as momentum, energy, and helicity. Since loading of such qu…
Probing Unification with Chandra HETGS and XMM-Newton EPIC and RGS Spectroscopy of the Narrow Emission Line Galaxy NGC 2110
Lee, Julia C.; Weaver, Kimberly A.; Marshall, Herman L. +2 more
We present results from Chandra HETGS (250 ks over two epochs) and XMM-Newton EPIC and RGS (60 ks) observations of NGC 2110, which has been historically classified as a narrow emission line galaxy. Our results support the interpretation that the source is a Seyfert 2 viewed through a patchy absorber. The nuclear X-ray spectrum of the source is bes…
The stellar halo of the edge-on galaxy NGC 891
Rejkuba, M.; Mouhcine, M.; Ibata, R.
Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we have resolved individual red giant branch stars in the outskirts of the edge-on galaxy NGC 891, down to ~2 mag fainter than the tip of the red giant branch. The data set allows investigation of the stellar populations in the outer regions of an analogue galaxy to the Mil…
Timing evidence in determining the accretion state of the Seyfert galaxy NGC 3783
Uttley, P.; Arévalo, P.; McHardy, I. M. +2 more
Previous observations with the Rossi X-ray Timing Explorer (RXTE) have suggested that the power spectral density (PSD) of NGC 3783 flattens to a slope near zero at low frequencies, in a similar manner to that of Galactic black hole X-ray binary systems (GBHs) in the `hard' state. The low radio flux emitted by this object, however, is inconsistent …