We present the discovery of a very peculiar L dwarf from the UKIDSS Large Area Survey (LAS), ULAS J222711-004547. Its very red infrared colours (MKO J-K = 2.79) make it the reddest brown dwarf discovered so far. The object was discovered as part of a large spectroscopic campaign aimed at constraining the sub-stellar birth rate. We obtained a

We discuss brown dwarf properties that can be measured from current and future deep surveys, and how fundamental parameters, such as the mass function and formation history may be measured. As well as the possibility of finding new populations of benchmark objects that can be used to refine the calibration of ultra-cool models with new precisely

Two new late-type L subdwarfs were discovered in our recent search of UKIDSS and SDSS. We discuss the signatures of halo brown dwarfs based on known and new L subdwarfs. These indicate that the halo stellar/substellar T_eff gap is likely between esdL4 and esdL6.

We present preliminary results of a brown dwarf (BD) detection in a ˜1000 star sample monitored with the ongoing PennState-Toruń Centre for Astronomy Planet Search. Contrary to most other projects, our sample contains a substantial fraction of evolved stars ranging from sub-giants up to bright giants, allowing us to study companions to stars more

In the last two decades, solar physics has greatly explored the 10^-3 polarimetric sensitivity level (referred to the continuum intensity). This has provided us with a quantitatively accurate picture of the photospheric magnetism for mean longitudinal fields in the range of about 5 Gauss. However, the same 10^-3 detection levels translate into a

We present the Data Release 9 Quasar (DR9Q) catalog from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III. The catalog includes all BOSS objects that were targeted as quasar candidates during the survey, are spectrocopically confirmed as quasars via visual inspection, have luminosities Mi[z = 2] -20.5 (in a