We present deep BVRI band images and H i line observations of the nearby, low surface brightness galaxy ESO215–G?009 which were obtained with the ANU 2.3-m Telescope and the Australia Telescope Compact Array, respectively. ESO215–G?009 was selected from the HIPASS Bright Galaxy Catalog because it has the second highest H i mass-to-light ratio of the galaxies with measured B band apparent magnit...

We construct a model for black hole formation in galactic bulges. The initial state is a slowly rotating isothermal sphere, with an effective transport speed and rotation rate Q. The black hole mass is determined when the aeff centrifugal radius of the collapse flow exceeds the capture radius of the central black hole. This model reproduces the observed correlation between black hole masses and...

The Earth's biggest magmatic events are believed to originate from massive melting when hot mantle plumes rising from the lowermost mantle reach the base of the lithosphere. Classical models predict large plume heads that cause kilometre-scale surface uplift, and narrow (100 km radius) plume tails that remain in the mantle after the plume head spreads below the lithosphere. However, in many cas...

reproductive age.3 However, other empirical evidence has indicated that state abortion restrictions have no such impact.4 The relationship between state-level abortion policies and birthrates is even murkier. Since the birthrate is the product of the pregnancy rate and the ratio of births to pregnancies, state abortion policies may affect birthrates by influencing one or both of these factors. ...

We present the results of Chandra, RXTE, and VLA observations of SGR 1900+14 in the immediate aftermath of its 2001 April 18 giant flare event. In the X-ray band we find the source in a pulsating and bursting state, with time-averaged 2–10 keV flux initially elevated by 20% above the source's previous quiescent periods. In the radio we establish upper limits on the strength of any persistent po...

High resolution (10 km s) [N II] echelle spectra, sampled every 13 arcsec in a 6 × 6 region around SN1987A were obtained on the CTIO 4m telescope. The map shows a complicated velocity structure consistent with that reported previously for the interstellar medium (ISM). Three components, Vhel = 265, 277 and 285 km s were identified as N157C (or the R1170-complex: Xu, Crotts & Kunkel 1995). The r...

Extended source size effects have been detected in photometric monitoring of gravitational microlensing events. We study similar effects in the centroid motion of an extended source lensed by a point mass. We show that the centroid motion of a source with uniform surface brightness can be obtained analytically. For a source with circularly symmetric limb-darkening profile, the centroid motion c...

Introduction: The Chicxulub Scientific Drilling Project (www.icdp-online.de) recovered a continuous core from a depth of 404 m (in Tertiary cover) to 1511 m (in a megablock of Cretaceous target sediments), penetrating ~100 m of melt-bearing impactites between 794 and 895 m. The Yaxcopoil-1 (YAX-1) borehole is ~60-65 km from the center of the Chicxulub structure, which is ~15 km beyond the limit...

We apply the Jeans equation to estimate masses for eight of the brightest dwarf spheroidal (dSph) galaxies. For Fornax, the dSph with the largest kinematic data set, we obtain a model-independent constraint on the maximum-circular velocity, Vmax = 20 +4 −3 km s . Although we obtain only lowerlimits of Vmax & 10 km s −1 for the remaining dSphs, we find that in all cases the enclosed mass at the ...