V723 Cas (Nova Cassiopeiae 1995): MERLIN observations from 1996 to 2001
ArXiv 0708.1158 (2007)
Abstract:
MERLIN observations of the unusually slow nova V723 Cas are presented. Nine epochs of 6-cm data between 1996 and 2001 are mapped, showing the initial expansion and brightening of the radio remnant, the development of structure and the final decline. A radio light curve is presented and fitted by the standard Hubble flow model for radio emission from novae in order to determine the values of various physical parameters for the shell. The model is consistent with the overall development of the radio emission. Assuming a distance of 2.39 (+/-0.38) kpc and a shell temperature of 17000 K, the model yields values for expansion velocity of 414 +/- 0.1 km s^-1 and shell mass of 1.13 +/- 0.04 * 10^-4 Msolar. These values are consistent with those derived from other observations although the ejected masses are rather higher than theoretical predictions. The structure of the shell is resolved by MERLIN and shows that the assumption of spherical symmetry in the standard model is unlikely to be correct.Tracing the jet contribution to the mid-IR over the 2005 outburst of GRO J1655-40 via broadband spectral modeling
(2007)
Erratum: “Discovery of Twin kHz QPOs in the Peculiar X-Ray Binary Circinus X-1” (ApJ, 653, 1435 [2006])
The Astrophysical Journal American Astronomical Society 664:1 (2007) 596-596
An empirical model for the beams of radio pulsars
ArXiv 0707.2547 (2007)
Abstract:
Motivated by recent results on the location of the radio emission in pulsar magnetospheres, we have developed a model which can account for the large diversity found in the average profile shapes of pulsars. At the centre of our model lies the idea that radio emission at a particular frequency arises from a wide range of altitudes above the surface of the star and that it is confined to a region close to the last open field lines. We assert that the radial height range over which emission occurs is responsible for the complex average pulse shapes rather than the transverse (longitudinal) range proposed in most current models. By implementing an abrupt change in the height range to discriminate between young, short-period, highly-energetic pulsars and their older counterparts, we obtain the observed transition between the simple and complex average pulse profiles observed in each group respectively. Monte Carlo simulations are used to demonstrate the match of our model to real observations.Peak Luminosities of the Hard States of GX 339-4: Implications for the Accretion Geometry, Disk Mass, and Black Hole Mass
The Astrophysical Journal American Astronomical Society 663:2 (2007) 1309-1314