Multi-epoch HST images have been obtained for the pre planetary nebulae CRL618, CRL2688, and Hen3-1475. Each object shows clear and idiosyncratic expansion patterns. CRL618 consists of several well defined fingers with sharp tips. The lengths of the tips have increased by identical factors, ˜7%, over the course of seven years, suggesting a common

The Tremaine-Weinberg method is a well-known model-independent technique for measuring density wave pattern speeds in spiral galaxies. Here we show how it can be applied to the data cubes (maps of surface brightness and velocity) obtained in Halpha emission using a Fabry-Perot spectrometer. One of the main difficulties, the discontinuity of the

The optical spectra of objects classified as QSOs in the SDSS DR6 are analyzed with the aim of determining the value of the fine structure constant in the past and then check for possible changes in the constant over cosmological timescales. The analysis is done by measuring the position of the fine structure lines of the [OIII] doublet (λλ4959 and

Close binarity can play a significant role in the shaping of planetary nebulae (PNe) as the system evolves through the common-envelope phase. We present the detection of two of the shortest orbital periods among PN binary central stars. These are Hen 2-428, a bipolar PN, and V458 Vul, a recent nova surrounded by a mildly bipolar planetary nebula

Hierarchical models predict that massive early-type galaxies (mETGs) are the latest systems to be in place into the cosmic scenario (below z ˜ 0. 5), conflicting with the observational phenomenon of galaxy mass downsizing, which poses that the most massive galaxies have been in place earlier that their lower-mass counterparts (since z ˜ 0. 7). We

I outline the goals of the `Declaration concerning the Evolving Rôle of Libraries in Research Centres' and describe progress in obtaining its official adoption as IAU policy.