ﻻ يوجد ملخص باللغة العربية
We present complete near-infrared (0.85-2.45 um), low-resolution (~100) spectra of a sample of 26 disk L-dwarfs with reliable optical spectral type classification. The observations have been obtained with NICS at the TNG using a prism-based optical element (the Amici device) that provides a complete spectrum of the source on the detector. Our observations show that low-resolution near-infrared spectroscopy can be used to determine the spectral classification of L-dwarfs in a fast but accurate way. We present a library of spectra that can be used as templates for spectral classification of faint dwarfs. We also discuss a set of near-infrared spectral indices well correlated with the optical spectral types that can be used to accurately classify L-dwarfs earlier than L6.
We present an analysis of high resolution spectra in the J band of five ultra cool dwarfs from M6 to L0. A new ab initio water vapour line list and existing line lists of FeH and CrH were used for spectra modelling. We find a good fit for the Mn I 12
We present a library of near-infrared (1.1-2.45 microns) medium-resolution (R~1500-2000) integral field spectra of 15 young M6-L0 dwarfs, composed of companions with known ages and of isolated objects. We use it to (re)derive the NIR spectral types,
We present near-infrared (1.0-2.4 micron) spectra confirming the youth and cool effective temperatures of 6 brown dwarfs and low mass stars with circumstellar disks toward the Chamaeleon II and Ophiuchus star forming regions. The spectrum of one of o
We develop a method to identify the spectroscopic signature of unresolved L-dwarf ultracool companions, which compares the spectra of candidates and their associated control stars using spectral ratio differences and residual spectra. We present SpeX
We present observations of 36 late-M dwarfs obtained with the KeckII/NIRSPEC in the J-band at a resolution of sim20,000. We have measured projected rotational velocities, absolute radial velocities, and pseudo-equivalent widths of atomic lines. 12 of