Observations of quiescent filaments show fine-scale structures, suggesting that they can be composed of small-scale threads or fibrils. Here, we study the oscillations of group of periodic fibrils in a Cartesian geometry using Bloch's theorem. The periodic array of fibrils provides a bridge between the seemingly different oscillations of a finite

We study the effects of a possible joint variation of the electron mass and the fine structure constant on the CMBR temperature fluctuation spectrum. We use the first-year WMAP (Bennet et al. 2003) data to estimate the values of the fine structure constant and of the electron mass at the decoupling time.

Apparent ZAHB F555W magnitude for 72 Galactic globular clusters, corresponding distance modulus in F555W, the reddening in flight system E(F439W-F555W) , the reddening in Johnson system E(B-V) and the metallicity in the Zinn & West (1984ApJS...55...45Z) and Carretta & Gratton (1997A&AS..121...95C) scales. (1 data file).

We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using IRMOS, 2MASS, and Spitzer observations, we conclude that there are 14 red supergiants in the cluster, compared with five, in what was previously

Spectroscopic observations have been obtained of eighteen RR Lyrae stars (RRLs) belonging to the ``12.4 hr clump'', a prominent halo overdensity in the QUEST RRLs survey. Ten blue horizontal branch stars in the same region of space that had been measured by Sirko et al. (2004) were added to this sample. Thirteen of the 28 stars in the whole sample

A chemical evolution model of the Galaxy has been computed to reproduce the O/H gradients from Galactic HII regions. This model solves the C enrichment problem because it fits the C/H and C/O gradients and the C and O histories of the solar vicinity. The model is based on C yields dependent on metallicity (Z) owing to stellar winds. The C yields of