Search Publications
ATCA observations of the very young Planetary Nebula SAO 244567
Umana, G.; Trigilio, C.; Leto, P. +2 more
The radio emission from the youngest known Planetary Nebula, SAO244567, has been mapped at 1384, 2368, 4800, 8640, 16832 and 18752 MHz by using the Australian Telescope Compact Array (ATCA). These observations constitute the first detailed radio study of this very interesting object, as they allow us to obtain the overall radio morphology of the s…
A feasibility study for measuring geomagnetic conversion of solar axions to x-rays in low Earth orbits
Davoudiasl, Hooman; Huber, Patrick
We present a detailed computation of the expected rate for geomagnetic conversion of solar axions to x-rays (GECOSAX) along the orbit of an x-ray satellite. We use realistic satellite orbits and propagation in time. A realistic model for the Earth's magnetic field, which properly accounts for its spatial non-uniformity, is used. We also account fo…
Collisional interaction limits between dark matter particles and baryons in `cooling flow' clusters
Hu, Jian; Lou, Yu-Qing
Presuming weak collisional interactions to exchange the kinetic energy between dark matter and baryonic matter in a galaxy cluster, we re-examine the effectiveness of this process in several `cooling flow' galaxy clusters using available X-ray observations and infer an upper limit on the heavy dark matter particle (DMP)-proton cross-section σ…
Properties of X-ray-selected broad absorption-line quasars
Page, M. J.; Seymour, N.; Kennea, J. A. +6 more
Broad absorption-line quasars (commonly termed BALQSOs) contain the most dramatic examples of active galactic nucleus (AGN) driven winds. The high absorbing columns in these winds, ~1024cm-2, ensure that BALQSOs are generally X-ray faint. This high X-ray absorption means that almost all BALQSOs have been discovered through op…
Variable X-Ray Absorption Toward the Gravitationally-Lensed Blazar PKS 1830-211
Garmire, Gordon P.; Mathur, Smita; Dai, Xinyu +2 more
We present X-ray spectral analysis of five Chandra and XMM-Newton observations of the gravitationally-lensed blazar PKS 1830-211 from 2000 to 2004. We show that the X-ray absorption toward PKS 1830-211 is a variable, and the variable absorption is most likely to be intrinsic with amplitudes of ~2 × 1022 30 × 1022 cm-2
HHSMT observations of the Venusian mesospheric temperature, winds, and CO abundance around the MESSENGER flyby
Hartogh, Paul; Jarchow, Christopher; Rengel, Miriam
We present submillimeter observations of 12CO J=3-2 and 2-1, and 13CO J=2-1 lines of the Venusian mesosphere and lower thermosphere with the Heinrich Hertz Submillimeter Telescope (HHSMT) taken around the second MESSENGER flyby of Venus on 5 June 2007. The observations cover a range of Venus solar elongations with different f…
Dynamical study of wide pairs of stars based on data from the WDS catalog
Kiselev, A. A.; Kiyaeva, O. V.; Izmailov, I. S.
Using the method of apparent motion parameters, we have studied the relative motion of the components in 561 pairs of wide ( ρ > 2″) and relatively nearby (Hipparcos parallaxes > 0.01″) visual double stars based on data from the WDS catalog. The minimum masses of the double stars have been calculated at given parallaxes. We have identified 3…
Relationship between FAC at plasma sheet boundary layers and AE index during storms from August to October, 2001
Zhang, T. L.; Dunlop, M. W.; Liu, Z. X. +2 more
IRAS22036+5306: an Al2O3 oxide-dominated post-AGB star
Maldoni, M. M.; Ireland, T. R.; Robinson, G.
Radiative transfer modelling of the Infrared Space Observatory (ISO) spectrum of IRAS22036+5306 has shown that its unusual 11-µm band can be suitably modelled with an alumina-olivine mixture substantially dominated by the former. The results of this work add further credence to recent findings that significant amounts of Al2O…
A Study of the Scale Height of the Thin Galactic Disk in the Solar Neighborhood
Zhu, Zi; Kong, Da-Li
An attempt is made to determine the scale height of the thin Galactic disk in the solar neighborhood using various stellar samples from the accurate astrometric data of the Hipparcos satellite. Using the Tycho color indices and considering the completeness of the samples, several samples were selected from the main sequence and the horizontal bran…