The term "Target of Opportunity" (ToO) is used in astronomy to identify unpredictable events whose study is of the highest scientific interest. For XMM-Newton a ToO is an astronomical event observable by its instruments, which cannot be predicted and scheduled on the time scale of one year, yet is scientifically significant enough to justify the

We present high-, mid-, and low-resolution spectroscopy of the field brown dwarf candidate PC 0025+0447 (M9.5) spanning a 4 yr baseline (1994-1998). The strength of the emission lines and the amount of optical veiling are very variable. Our spectra taken at an epoch of low veiling allow us to detect the lithium resonance line, which was not

In the framework of our narrow-band survey of the Local Group galaxies, we present the results of the search for planetary nebulae (PNe) in the dwarf irregular galaxies IC 10, Leo A and Sextans A. Using the standard on-band/off-band technique, sixteen new candidate PNe have been discovered in the closest starburst galaxy, IC 10. The optical size of

In the framework of the Local Group Census (LGC), a survey of the Local Group (LG) galaxies above Dec =-30° aimed at surveying the populations that have strong emission lines, we have searched for planetary nebulae (PNe) in the low-metallicity dwarf irregular galaxies IC 1613, WLM, GR 8. Two new candidate PNe have been found in IC 1613, one in WLM

Recent GLIMPSE data analysed by Benjamin et al. (2005) have further confirmed the hypothesis of the existence of an in-plane long bar that is different from the bulge of the Milky Way with the same characteristics that were emphasized some years ago by our team. In this contribution, we briefly discuss the published literature on the topic and

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