We present Chandra, XMM-Newton, and Swift observations of the quiescent neutron star in the transient low-mass X-ray binary MAXI J0556-332. Observations of the source made during outburst (with the Rossi X-ray Timing Explorer) reveal tracks in its X-ray color-color and hardness-intensity diagrams that closely resemble those of the neutron-star Z

Optical spectrophotometry of the active galaxy PKS 0521-365 over a period of 7 years is reported, together with the analysis of IUE archival spectra. The Hα emission line intensity varied by more than a factor of 2 during the monitoring. Similar amplitude variations are observed in the optical and UV continuum, which however are not simply

This paper discusses the properties of the European Large Area ISO Survey (ELAIS) 15-μm quasars and tries to establish a robust method of quasar selection for future use within the Spitzer Wide-Area Infrared Extragalactic Survey (SWIRE) framework. The importance of good-quality ground-based optical data is stressed, both for the selection of

We investigate the nature of the substantial population of high-redshift galaxies with Js-Ks>=2.3 colors recently discovered as part of our Faint Infrared Extragalactic Survey (FIRES). This color cut efficiently isolates galaxies at z>2 with red rest-frame optical colors (``distant red galaxies'' [DRGs]). We select Js-Ks>=2.3 objects in both FIRES

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The identification of the Jovian frequency spectrum obtained by Schmider et al. (1990, 1991) is proposed from Doppler shift observations of the solar sodium D line reflected by the planet, as a signature of Jovian global-pressure modes. The spectrum, derived from 4 nights of observations, presents high-amplitude peaks whose origin in undoubtedly