The sub-stellar birth rate from UKIDSS★

Day-Jones, A. C.; Marocco, F.; Pinfield, D. J.; Zhang, ZH; Burningham, B.; Deacon, N. R.; Ruíz, M. T.; Gallardo, José; Jones, H. R. A.; Lucas, P. W.; Jenkins, James S.; Gomes, Jorge; Folkes, S. L.; Clarke, J. R. A.

doi:10.1093/mnras/sts685

Cited by 55 publications

(52 citation statements)

References 84 publications

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“…However, close inspection reveals specific discrepancies near 1.3 and 1.6 μm, and a subtle "dip" feature at 1.62 μm. Such features have been previously noted in the combined-light spectra of very low mass spectral binary systems with late-type M or L dwarf primaries and T dwarf secondaries (e.g., Cruz et al 2004;Burgasser 2007b;Burgasser et al 2010Burgasser et al , 2011Burgasser et al , 2012Gelino & Burgasser 2010;Kirkpatrick et al 2012;Day-Jones et al 2013;Deacon et al 2014;Bardalez Gagliuffi et al 2014). To assess whether WISE J0720-0846 is such a system, we used the fitting method described in Burgasser et al (2010), comparing the spectrum of WISE J0720-0846 to 699 single star templates and 107,646 binary templates from the SPL.…”

Section: Identification As a Spectral Binarymentioning

confidence: 98%

WISE J072003.20-084651.2: AN OLD AND ACTIVE M9.5 + T5 SPECTRAL BINARY 6 pc FROM THE SUN

Burgasser

Gillon

Melis

et al. 2015

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We report observations of the recently discovered, nearby late-M dwarf WISE J072003.20-084651.2. New astrometric measurements obtained with the TRAPPIST telescope improve the distance measurement to 6.0 ± 1.0 pc and confirm the low tangential velocity (3.5 ± 0.6 km s −1 ) reported by Scholz. Low-resolution optical spectroscopy indicates a spectral type of M9.5 and prominent Hα emission (á ñ a L L log H 10 bol = −4.68 ± 0.06), but no evidence of subsolar metallicity or Li I absorption. Near-infrared spectroscopy reveals subtle peculiarities that can be explained by the presence of a T5 binary companion, and high-resolution laser guide star adaptive optics imaging reveals a faint (ΔH = 4.1) candidate source  0. 14 (0.8 AU) from the primary. With high-resolution optical and near-infrared spectroscopy, we measure a stable radial velocity of +83.8 ± 0.3 km s −1 , indicative of old disk kinematics and consistent with the angular separation of the possible companion. We measure a projected rotational velocity of v sin i = 8.0 ± 0.5 km s −1 and find evidence of low-level variabilty (∼1.5%) in a 13 day TRAPPIST light curve, but cannot robustly constrain the rotational period. We also observe episodic changes in brightness (1%-2%) and occasional flare bursts (4%-8%) with a 0.8% duty cycle, and order-of-magnitude variations in Hα line strength. Combined, these observations reveal WISE J0720-0846 to be an old, very low-mass binary whose components straddle the hydrogen burning minimum mass, and whose primary is a relatively rapid rotator and magnetically active. It is one of only two known binaries among late M dwarfs within 10 pc of the Sun, both of which harbor a mid T-type brown dwarf companion. We show that while this specific configuration is rare (≲1.6% probability), roughly 25% of binary companions to late-type M dwarfs in the local population are likely low-temperature T or Y brown dwarfs.

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Section: Identification As a Spectral Binarymentioning

confidence: 98%

WISE J072003.20-084651.2: AN OLD AND ACTIVE M9.5 + T5 SPECTRAL BINARY 6 pc FROM THE SUN

Burgasser

Gillon

Melis

et al. 2015

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“…We searched DwarfArchives (update of 6th of November 2012) for known L and T dwarfs with 13.0 < J < 17.5 in the UKIDSS LAS Y JHK footprint, supplemented by the recent samples of Burningham et al (2013), Day-Jones et al (2013), Kirkpatrick et al (2011), and Mace et al (2013). A few sources with unreliable photometry in any of the eight bands (e.g.…”

Section: Possible Sources Of Bias In the Colour Relationsmentioning

confidence: 99%

“…A good example of the state of the art in obtaining a statistical sample of brown dwarfs is the study of the sub-stellar birth rate by Day-Jones et al (2013). They classified 63 new L and T dwarfs brighter than J = 18.1, using X-shooter spectroscopy on the Very Large Telescope (VLT), after selecting them through colour cuts.…”

Section: Introductionmentioning

confidence: 99%

Photometric brown-dwarf classification

Skrzypek

Warren

Faherty

et al. 2015

A&A

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Aims. We present a method, named photo-type, to identify and accurately classify L and T dwarfs onto the standard spectral classification system using photometry alone. This enables the creation of large and deep homogeneous samples of these objects efficiently, without the need for spectroscopy. Methods. We created a catalogue of point sources with photometry in 8 bands, ranging from 0.75 to 4.6 μm, selected from an area of 3344 deg 2 , by combining SDSS, UKIDSS LAS, and WISE data. Sources with 13.0 < J < 17.5, and Y − J > 0.8, were then classified by comparison against template colours of quasars, stars, and brown dwarfs. The L and T templates, spectral types L0 to T8, were created by identifying previously known sources with spectroscopic classifications, and fitting polynomial relations between colour and spectral type. Results. Of the 192 known L and T dwarfs with reliable photometry in the surveyed area and magnitude range, 189 are recovered by our selection and classification method. We have quantified the accuracy of the classification method both externally, with spectroscopy, and internally, by creating synthetic catalogues and accounting for the uncertainties. We find that, brighter than J = 17.5, photo-type classifications are accurate to one spectral sub-type, and are therefore competitive with spectroscopic classifications. The resultant catalogue of 1157 L and T dwarfs will be presented in a companion paper.

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“…Large samples have revealed the mass and luminosity functions of the local ultracool population (e.g., Allen et al 2005;Cruz et al 2007;Burningham et al 2010b). Measurements of the space density of brown dwarfs (e.g., Metchev et al 2008;Reid et al 2008) have identified a relative paucity of L/T transition dwarfs, indicating that this evolutionary phase is short-lived and constraining the birth history of substellar objects (e.g., Day-Jones et al 2013;Marocco et al 2015). The surveys have also enhanced brown dwarf searches in star-forming regions (e.g., Lodieu et al 2009;Martín et al 2010), important for determination of the substellar initial mass function.…”

Section: Introductionmentioning

confidence: 99%

Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3 π Survey

Best

Magnier

Liu

et al. 2017

ApJS

119

110

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe present a catalog of 9888 M, L and T dwarfs detected in the Pan-STARRS13π Survey (PS1), covering threequarters of the sky. Our catalog contains nearly all known objects of spectral types L0-T2 in the PS1 field, with objects as early as M0 and as late as T9, and includes PS1, 2MASS, AllWISE, and GaiaDR1 photometry. We analyze the different types of photometry reported by PS1 and use two types in our catalog in order to maximize both depth and accuracy. Using parallaxes from the literature, we construct empirical SEDs for field ultracool dwarfs spanning 0.5-12 μm. We determine typical colors of M0-T9 dwarfs and highlight the distinctive colors of subdwarfs and young objects. We combine astrometry from PS1, 2MASS, and GaiaDR1 to calculate new proper motions for our catalog. We achieve a median precision of 2.9mas yr −1 , a factor of ≈3−10 improvement over previous large catalogs. Our catalog contains proper motions for 2405M6-T9 dwarfs and includes the largest set of homogeneous proper motions for L and T dwarfs published to date, 406objects for which there were no previous measurements, and 1176objects for which we improve upon previous literature values. We analyze the kinematics of ultracool dwarfs in our catalog and find evidence that bluer but otherwise generic late-M and Lfield dwarfs (i.e., not subdwarfs) tend to have tangential velocities higher than those of typical field objects. With the public release of the PS1 data, this survey will continue to be an essential tool for characterizing the ultracool dwarf population.

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The sub-stellar birth rate from UKIDSS★

Cited by 55 publications

References 84 publications

WISE J072003.20-084651.2: AN OLD AND ACTIVE M9.5 + T5 SPECTRAL BINARY 6 pc FROM THE SUN

WISE J072003.20-084651.2: AN OLD AND ACTIVE M9.5 + T5 SPECTRAL BINARY 6 pc FROM THE SUN

Photometric brown-dwarf classification

Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3 π Survey

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