Context: Free-floating substellar candidates with estimated theoretical masses of as low as ∼5 Jupiter masses have been found in the ∼3 Myr old σ Orionis open cluster. As the overlap with the planetary mass domain increases, the question of how these objects form becomes important. The determination of their number density and whether a mass cut

We present Spitzer/IRAC and MIPS 24 μm observations for 28 brown dwarfs in the Upper Scorpius (UppSco) region. We find a disk fraction of 10.7%+8.7% -3.3%. One object shows a small excess at 24 μm but none at shorter wavelengths, and may be a candidate transition disk. Three objects show emission in the 10 μm silicate feature and we present

The currently active neutron star transient and atoll source Aql X-1 (Linares et al., ATEL #2288) has begun the transition from the hard (extreme island) state to the soft (banana) state (Rodriguez et al. ATEL #2299). This transition likely began around 2009 Nov 15 (MJD = 55150). The latest RXTE PCA observation (2009 Nov 17, MJD=55152.17+/-0.02, 2

On November 1st. RXTE-PCA scans of the Aql region detected X-ray emission consistent with the neutron star transient and atoll source Aql X-1. Further scans and pointed PCA observations show a rising X-ray flux; the most recent flux is about 40 mCrab. Swift observed the field for about 2.5 ksec on November 8th, 2009, and detected a bright X-ray

We present the results of a homogeneous X-ray analysis for 82 nearby low-ionisation, narrow emission-line regions (LINERs) selected from the catalogue of Carrillo et al. (1999, Rev. Mex. Astron. Astrofis., 35, 187). All sources have available Chandra (68 sources) and/or XMM-Newton (55 sources) observations. This is the largest sample of LINERs with

Atomic data and equivalent widths for 15 red clump giants in 5 open clusters: Cr 110, NGC 2099, NGC 2420, M 67, NGC 7789. (2 data files).