Placing the Deep Impact Mission into Context: Two Decades of Observations of 9P/Tempel 1 from McDonald ObservatoryWe report on low-spectral resolution observations of comet 9P/Tempel 1 from 1983, 1989, 1994 and 2005 using the 2.7m Harlan J. Smith telescope of McDonald Observatory. This comet was the target of…Anita L. Cochran, Edwin S. Barker, Marcos D. Caballero et al.·Sep 2, 2008SaveLearn
The 2008 February superoutburst of V452 CasObservations of the 2008 February outburst of V452 Cas show that the profile, duration and magnitude at maximum were very similar to the previous superoutburst in 2007 September. Low-amplitude…Christopher Lloyd, Roger Pickard, Jeremy Shears et al.·Sep 2, 2008SaveLearn
Serendipitous VLBI detection of rapid, large-amplitude, intraday variability in QSO 1156+295We report a serendipitous detection of rapid, large amplitude flux density variations in the highly core-dominated, flat-spectrum radio quasar 1156+295 during an observing session at the Very Long…T. Savolainen, Y. Y. Kovalev·Sep 2, 2008SaveLearn
Statistics of young starforming complexes in spiral galaxies using NIR photometryAll slightly extended sources were identified on deep K-band maps of 46 spiral galaxies reaching at least K=20.3 mag/arcsec2 at a signal-to-noise level of 3. The galaxies had inclination angles <65…P. Grosbol, H. Dottori·Sep 2, 2008SaveLearn
Accretion and plasma outflow from dissipationless discsWe consider an extreme case of disc accretion onto a gravitating centre when the viscosity in the disc is negligible. The angular momentum and the rotational energy of the accreted matter is carried…Sergei Bogovalov, Stanislav Kelner·Sep 2, 2008SaveLearn
High-resolution radio continuum survey of M33: III. Magnetic fieldsUsing the linearly polarized intensity and polarization angle data at 3.6, 6.2 and 20 cm, we determine variations of Faraday rotation and depolarization across the nearby galaxy M33. A 3-D model of…F. S. Tabatabaei, M. Krause, A. Fletcher et al.·Sep 2, 2008SaveLearn
Thermal disc emission from a rotating black hole: X-ray polarization signaturesThermal emission from the accretion disc around a black hole can be polarized, due to Thomson scattering in a disc atmosphere. In Newtonian space, the polarization angle must be either parallel or…M. Dovciak, F. Muleri, R. W. Goosmann et al.·Sep 2, 2008SaveLearn
Toroidal field instability and eddy viscosity in Taylor-Couette flowsToroidal magnetic fields subject to the Tayler instability can transport angular momentum. We show that the Maxwell and Reynolds stress of the nonaxisymmetric field pattern depend linearly on the…M. Gellert, G. Rüdiger·Sep 2, 2008SaveLearn
Optical Spectroscopy of the ULX-Associated Nebula MF16We present the results of optical panoramic and long-slit spectroscopy of the nebula MF16 associated with the Ultraluminous X-ray Source NGC6946 ULX-1. More than 20 new emission lines are identified…Pavel Abolmasov, S. Fabrika, O. Sholukhova et al.·Sep 2, 2008SaveLearn
The Nearest OB Association: Scorpius-Centaurus (Sco OB2)We summarize observational results on the stellar population and star formation history of the Scorpius-Centaurus OB Association (Sco OB2), the nearest region of recent massive star formation. It…Thomas Preibisch, Eric Mamajek·Sep 2, 2008SaveLearn
CME liftoff with high-frequency fragmented type II burst emissionAims: Solar radio type II bursts are rarely seen at frequencies higher than a few hundred MHz. Since metric type II bursts are thought to be signatures of propagating shock waves, it is of interest…S. Pohjolainen, J. Pomoell, R. Vainio·Sep 2, 2008SaveLearn
The formation of planetary disks and winds: an ultraviolet viewPlanetary systems are angular momentum reservoirs generated during star formation. This accretion process produces very powerful engines able to drive the optical jets and the molecular outflows. A…Ana I. Gomez de Castro·Sep 2, 2008SaveLearn
VLA observations of the "water fountain" IRAS 16552-3050We present Very Large Array (VLA) observations of the water maser emission towards IRAS 16552-3050. The maser emission shows a velocity spread of ~170 km/s, and a bipolar distribution with a…Olga Suárez, J. F. Gómez, L. F. Miranda·Sep 2, 2008SaveLearn
Weighing black holes from zero to high redshiftThe application of the virial theorem provides a tool to estimate supermassive black hole (BH) masses in large samples of active galactic nuclei (AGN) with broad emission lines at all redshifts and…A. Marconi, D. Axon, R. Maiolino et al.·Sep 2, 2008SaveLearn
Natural Transfer of Viable Microbes in Space from Planets in the Extra-Solar Systems to a Planet in our Solar System and Vice-VersaWe investigate whether it is possible that viable microbes could have been transported to Earth from the planets in extra-solar systems by means of natural vehicles such as ejecta expelled by comet…Mauri Valtonen, Pasi Nurmi, Jia-Qing Zheng et al.·Sep 2, 2008SaveLearn
Age determinations of the open star clusters King 14 and NGC 146We based on 2MASS J and Ks photometry for the open star clusters King 14 and NGC 146, and using color magnitude diagrams with isochrones fit we have found an age of log(age) = 7.8 (63 8 Myr) for…Valentin Kopchev, Petko Nedialkov, Georgy Petrov·Sep 2, 2008SaveLearn
Estimation of Cosmological Parameters from HI Observations of Post-reionization EpochThe emission from neutral hydrogen (HI) clouds in the post-reionization era (z < 6), too faint to be individually detected, is present as a diffuse background in all low frequency radio observations…Somnath Bharadwaj, Shiv K. Sethi, Tarun Deep Saini·Sep 2, 2008SaveLearn
Numerical simulations of buoyancy instabilities in galaxy cluster plasmas with cosmic rays and anisotropic thermal conductionIn clusters of galaxies, the specific entropy of intracluster plasma increases outwards. Nevertheless, a number of recent studies have shown that the intracluster medium is subject to buoyancy…Yann Rasera, Benjamin Chandran·Sep 2, 2008SaveLearn
Orbital and superorbital variability and their coupling in X-ray binariesWe review X-ray flux modulation from X-ray binaries on time scales corresponding to the orbital period and those at longer time scales (so called superorbital). Those modulations provide a powerful…Andrzej A. Zdziarski, Juri Poutanen, Askar Ibragimov et al.·Sep 2, 2008SaveLearn
The Cepheid Galactic InternetWe propose that a sufficiently advanced civilization may employ Cepheid variable stars as beacons to transmit all-call information throughout the galaxy and beyond. One can construct many scenarios…John G. Learned, R-P. Kudritzki, Sandip Pakvasa et al.·Sep 2, 2008SaveLearn
The discrete dipole approximation for periodic targets I. theory and testsThe discrete-dipole approximation (DDA) is a powerful method for calculating absorption and scattering by targets that have sizes smaller than or comparable to the wavelength of the incident…B. T. Draine, P. J. Flatau·Sep 2, 2008SaveLearn
Pressure gradients, shell crossing singularities and acoustic oscillations - application to inhomogeneous cosmological modelsInhomogeneous cosmological models have recently become a very interesting alternative to standard cosmology. This is because these models are able to fit cosmological observations without the need…Krzysztof Bolejko, Paul Lasky·Sep 2, 2008SaveLearn
Jitter radiation images, spectra, and light curves from a relativistic spherical blastwaveWe consider radiation emitted by the jitter mechanism in a Blandford-McKee self-similar blastwave. We assume the magnetic field configuration throughout the whole blastwave meets the condition for…Brian J. Morsony, Jared C. Workman, Davide Lazzati et al.·Sep 2, 2008SaveLearn
Massive black hole binary mergers within sub-pc scale gas discs[ABRIDGED] We study supermassive black hole binary mergers driven by angular momentum loss to small-scale gas discs. Such binaries form after major galaxy mergers, but their fate is unclear since…J. Cuadra, P. J. Armitage, R. D. Alexander et al.·Sep 1, 2008SaveLearn
Galactic dynamo action in presence of stochastic alpha and shearUsing a one-dimensional αω-dynamo model appropriate to galaxies, we study the possibility of dynamo action driven by a stochastic alpha effect and shear. To determine the field evolution, one needs…Sharanya Sur, Kandaswamy Subramanian·Sep 1, 2008SaveLearn