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We present the results of a systematic search for molecular outflows in 68 Very Low Luminosity Objects (VeLLOs) from single-dish observations in CO isotopologues which find 16 VeLLOs showing clear outflow signatures in the CO maps. With…

In this paper we present new and improved data on 38 cool white dwarfs identified by Oppenheimer et al. 2001 (OHDHS) as candidate dark halo objects. Using the high-res spectra obtained with LRIS, we measure radial velocities for 13 WDs that…

Ultra-light dark matter (ULDM) is a compelling candidate for cosmological dark matter. If ULDM interacts with ordinary matter, it can induce measurable, characteristic signals in pulsar-timing data because it causes the orbits of pulsars in…

High Energy Astrophysical Phenomena · Physics 2025-06-16 Pavel Kůs , Diana López Nacir , Federico R. Urban

We present the discovery of fifteen new T2.5-T7.5 dwarfs (with estimated distances between ~24-93pc, identified in the first three main data releases of the UKIRT Infrared Deep Sky Survey. This brings the total number of T dwarfs discovered…

Ultracool dwarfs represent a significant proportion of stars in the Milky Way,and deep samples of these sources have the potential to constrain the formation history and evolution of low-mass objects in the Galaxy. Until recently, spectral…

We report on the search for new eclipsing white dwarf plus main-sequence (WDMS) binaries in the light curves of the Catalina surveys. We use a colour selected list of almost 2000 candidate WDMS systems from the Sloan Digital Sky Survey,…

We present a data-driven approach to automatically detect L dwarfs from Sloan Digital Sky Survey(SDSS) images using an improved Faster R-CNN framework based on deep learning. The established L dwarf automatic detection (LDAD) model…

Instrumentation and Methods for Astrophysics · Physics 2023-04-12 Zhi Cao , Zhenping Yi , Jingchang Pan , Hao Su , Yude Bu , Xiao Kong , Ali Luo

The frequency of multiple systems and their properties are key constraints of stellar formation and evolution. Formation mechanisms of very low-mass (VLM) objects are still under considerable debate and an accurate assessment of their…

Solar and Stellar Astrophysics · Physics 2017-02-01 M. C. Galvez-Ortiz , E. Solano , N. Lodieu , M. Aberasturi

We present initial results of an all-sky search for late-type dwarfs within 20 pc of the Sun using the New Luyten Two-Tenths (NLTT) catalog cross-referenced with the 2-Micron All Sky Survey (2MASS) database. The results were obtained with…

Astrophysics · Physics 2009-11-07 Kelle L. Cruz , I. Neill Reid

We report the results of an infrared Doppler survey designed to detect brown dwarf and giant planetary companions to a magnitude-limited sample of ultracool dwarfs. Using the NIRSPEC spectrograph on the Keck II telescope, we obtained…

Solar and Stellar Astrophysics · Physics 2015-05-19 Cullen H. Blake , David Charbonneau , Russel J. White

Aims. We demonstrate the feasibility of determining parallaxes for nearby objects with theWide Field Camera on the United Kingdom Infrared Telescope (UKIRT) using the UKIRT Infrared Deep Sky Survey as a first epoch. We determine physical…

We present a UVES/VLT high resolution atlas of three L dwarfs and one T dwarf system, spectral classes at which most of the objects are brown dwarfs. Our atlas covers the optical region from H$\alpha$ up to the near infrared at 1 $\mu$m. We…

Astrophysics · Physics 2009-11-13 A. Reiners , D. Homeier , P. H. Hauschildt , F. Allard

New near-infrared large-area sky surveys (e.g. UKIDSS, CFBDS, WISE) go deeper than 2MASS and aim at detecting brown dwarfs lurking in the Solar neighbourhood which are even fainter than the latest known T-type objects, so-called Y dwarfs.…

Astrophysics of Galaxies · Physics 2015-05-18 R. -D. Scholz

We present a catalog of 9888 M, L and T dwarfs detected in the Pan-STARRS1 3$\pi$ Survey (PS1), covering three-quarters of the sky. Our catalog contains nearly all known objects of spectral types L0-T2 in the PS1 field, with objects as…

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey (SDSS). For each spectrum, we provide measurements of the spectral type, a number of molecular bandheads,…

We present a Python spectrophotometry extraction tool tailored for fast-moving point sources detected in the SPHEREx mission, and use it to construct a set of 0.75-5.0 $\mu$m low-resolution ($\lambda/\Delta\lambda \sim 50$)…

Rotationally modulated photometric variability of ultracool dwarfs encodes key information about cloud structure and temperature contrasts. Large homogeneous optical datasets are crucial for linking atmospheric heterogeneity to fundamental…

Solar and Stellar Astrophysics · Physics 2026-05-05 Haomiao Huang , Shu Wang , Xiaodian Chen , Zhijun Tu , Jifeng Liu

We report the discovery of a very cool d/sdL7+T7.5p common proper motion binary system, SDSS J1416+13AB, found by cross-matching the UKIDSS Large Area Survey Data Release 5 against the Sloan Digital Sky Survey Data Release 7. The d/sdL7 is…

As part of our comprehensive, ongoing characterisation of the low-mass end of the main sequence in the Solar neighbourhood, we used the OSIRIS instrument at the 10.4 m Gran Telescopio Canarias to acquire low- and mid-resolution…

The evolution of brown dwarfs from L to T spectral types is one of the least understood aspects of the ultracool population, partly for lack of a large, well-defined, and well-characterized sample in the L/T transition. To improve the…