Rice, Emily L., Barman, T., McLean, Ian S., Prato, L., Kirkpatrick, J. Davy
By comparing near-infrared spectra with atmosphere models, we infer the effective temperature, surface gravity, projected rotational velocity, and radial velocity for 21 very-low-mass stars and brown...
2MASS J06164006−6407194: the first outer halo L subdwarf (2009)
Cushing, Michael C., Looper, Dagney, Burgasser, Adam J., Kirkpatrick, J. Davy, Faherty, Jacqueline
We present the serendipitous discovery of an L subdwarf in the Two Micron All Sky Survey (2MASS) J06164006–6407194, in a search of the 2MASS for T dwarfs. Its spectrum exhibits features indicative...
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present an analysis of 23 L dwarfs whose optical spectra display unusual features. Twenty-one were uncovered during our search for nearby, late-type objects using the Two Micron All Sky Survey,...
Kirkpatrick, J. Davy, Cruz, Kelle L., Barman, Travis S., Burgasser, Adam J., Looper, Dagny L., Tinney, C. G., ...
Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed...
2MASS J09393548–2448279: The coldest and least luminous brown dwarf binary known? (2008)
Burgasser, Adam J., Tinney, C. G., Cushing, Michael C., Saumon, Didier, Marley, Mark S., Bennett, Clara S., ...
Determinations of the luminosity and atmospheric properties of the T8 brown dwarf 2MASS J09393548 - 2448279 are presented, based on Spitzer IRAC and IRS observations and ground-based astrometry. We...
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present an analysis of 23 L dwarfs whose optical spectra display unusual features. Twenty-one were uncovered during our search for nearby, late-type objects using the Two Micron All-Sky Survey...
Looper, Dagny L., Kirkpatrick, J. Davy, Cutri, Roc M., Barman, Travis, Burgasser, Adam J., Cushing, Michael C., ...
We present the discovery of two nearby L dwarfs from our 2MASS proper-motion search, which uses multiepoch 2MASS observations covering ~4700 deg^2 of sky. 2MASS J18212815+1414010 and 2MASS...
Discovery of a T dwarf binary with the largest known J-band flux reversal (2008)
Looper, Dagny L., Gelino, Christopher R., Burgasser, Adam J., Kirkpatrick, J. Davy
We present Keck laser guide star observations of two T2.5 dwarfs-2MASS J11061197+2754225 and 2MASS J14044941-3159329-using NIRC2 on Keck II and find 2MASS J14044941-3159329 to be a 0.13" binary. This...
Mid-infrared selection of brown dwarfs and high-redshift quasars (2008)
Stern, Daniel, Kirkpatrick, J. Davy, Allen, Lori E., Bian, Chao, Blain, Andrew, Brand, Kate, ...
We discuss color selection of rare objects in a wide-field multiband survey spanning from the optical to the mid-infrared. Simple color criteria simultaneously identify and distinguish two of the...
Plavchan, Peter, Jura, M., Kirkpatrick, J. Davy, Cutri, Roc M., Gallagher, S. C.
The Two Micron All Sky Survey (2MASS) photometric calibration observations cover ~6 square degrees on the sky in 35 ‘‘calibration fields, ’’ each sampled in nominal photometric conditions...
Meeting the cool neighbors. X. Ultracool dwarfs from the 2MASS All-Sky data reslease (2008)
Reid, I. Neill, Cruz, Kelle L., Kirkpatrick, J. Davy, Allen, Peter R., Mungall, F., Liebert, James, ...
Using data from the 2 Micron All Sky Survey All-Sky Point Source Catalogue, we have extended our census of nearby ultracool dwarfs to cover the full celestial sphere above Galactic latitude of 15°....
Kirkpatrick, J. Davy, Cruz, Kelle L., Barman, Travis S., Burgasser, Adam J., Looper, Dagny L., Tinney, C. G., ...
Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed...
Moderate-resolution Spitzer infrared spectrograph observations of M, L, and T dwarfs (2008)
Mainzer, A. K., Roellig, Thomas L., Saumon, D., Marley, Mark S., Cushing, Michael C., Sloan, G. C., ...
We present 10-19 μm moderate-resolution spectra of 10 M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. The IRS...
HN Peg B: A Test of Models of the L to T Dwarf Transition (2008)
Leggett, S. K., Saumon, D., Albert, Loic, Cushing, Michael C., Liu, Michael C., Luhman, K. L., ...
Luhman and collaborators recently discovered an early-T dwarf companion to the G0 dwarf star HN Peg, using Spitzer Infrared Array Camera (IRAC) images. Companionship was established on the basis of...
Meeting the Cool Neighbors X: Ultracool dwarfs from the 2MASS All-Sky Data Release (2008)
Reid, I. Neill, Cruz, Kelle L., Kirkpatrick, J. Davy, Allen, Peter R., Mungall, F., Liebert, James, ...
Using data from the 2MASS All-Sky Point Source Catalogue, we have extended our census of nearby ultracool dwarfs to cover the full celestial sphere above Galactic latitute 15 degrees. Starting with...
Looper, Dagny L., Kirkpatrick, J. Davy, Cutri, Roc M., Barman, Travis, Burgasser, Adam J., Cushing, Michael C., ...
We present the discovery of two nearby L dwarfs from our 2MASS proper motion search, which uses multi-epoch 2MASS observations covering ~4700 square degrees of sky. 2MASS J18212815+1414010 and 2MASS...
HN Peg B: A Test of Models of the L to T Dwarf Transition (2008)
Leggett, S. K., Saumon, D., Albert, Loic, Cushing, Michael. C., Liu, Michael C., Luhman, K. L., ...
Luhman and collaborators recently discovered an early-T dwarf companion to the G0 dwarf star HN Peg, using Spitzer Infrared Array Camera (IRAC) images. Companionship was established on the basis of...
Metchev, Stanimir A., Kirkpatrick, J. Davy, Berriman, G. Bruce, Looper, Dagny
We report new L and T dwarfs found in a cross-match of the SDSS Data Release 1 and 2MASS. Our simultaneous search of the two databases effectively allows us to relax the criteria for object detection...
Plavchan, Peter, Jura, M., Kirkpatrick, J. Davy, Cutri, Roc M., Gallagher, S. C.
The Two Micron All Sky Survey (2MASS) photometric calibration observations cover ~6 square degrees on the sky in 35 "calibration fields", each sampled in nominal photometric conditions between 562...
Clouds, Gravity, and Metallicity in Blue L Dwarfs: The Case of 2MASS J11263991–5003550* (2008)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Cruz, Kelle L., Swift, Brandon J.
Optical and near-infrared spectroscopy of the newly discovered peculiar L dwarf 2MASS J11263991–5003550 are presented. Folkes et al. classified this source as a high proper motion L9±1 dwarf based...
Commission 45: spectral classification (2008)
Giridhar, Sunetra, Gray, Richard O., Corbally, Christopher J., Eyer, Laurent, Irwin, Michael J., ...
This report gives an update of developments (since the last General Assembly at Prague) in the areas that are of relevance to the commission. In addition to numerous papers, a new monograph entitled...
Patrick J. Lowrance, Dean C. Hines, J. Davy Kirkpatrick, David W. Koerner, Frank Low, Marcia Rieke, ...
We present the discovery of a candidate substellar object in a survey of young stars in the solar vicinity using the sensitivity and spatial resolution afforded by the NICMOS coronagraph on the...
Patrick J. Lowrance, Glenn Schneider, J. Davy Kirkpatrick, E. E. Becklin, Alycia J. Weinberger, B. Zuckerman, ...
We present the discovery of a candidate substellar companion from a survey of nearby young stars made with the Near-Infrared Camera and Multiobject Spectrometer coronagraph on the Hubble Space...
Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, Adam Burrows, James Liebert, ...
We present near-infrared spectra for a sample of T dwarfs, including 11 new discoveries made using the 2 Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs by...
J. Davy Kirkpatrick, I. Neil Reid, James Liebert, John E. Gizis, Adam J. Burgasser, G. Monet, ...
We present JHK, photometry, far red spectra, and spectral classifications for an additional 67 L dwarfs discovered by the Two Micron All Sky Survey. One of the goals of this new search was to locate...
John E. Gizis, J. Davy Kirkpatrick, John C. Wilson
We report the discovery of a probable brown dwarf companion to the nearby K2 dwarf GJ 1048 using the Two Micron All-Sky Survey (2MASS). This source, 2MASSI 50235599-233120 or GJ 1048B, has 2MASS...
Adam J. Burgasser, J. Davy Kirkpatrick, I. Neill Reid, James Liebert, John E. Gizis, Michael E. Brown
We report the detection of Hff emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux, log(L...
John E. Gizis, J. Davy Kirkpatrick, Adam Burgasser, I. Neill Reid, David G. Monet, James Liebert, ...
We use three field L and T dwarfs that were discovered to be wide companions to known stars by the Two Micron All-Sky Survey to derive a preliminary brown dwarf companion frequency. Observed L and T...
Metchev, Stanimir, Kirkpatrick, J. Davy, Berriman, G. Bruce, Looper, Dagny
We report new L and T dwarfs found in a cross-match of the SDSS Data Release 1 and 2MASS. Our simultaneous search of the two databases effectively allows us to relax the criteria for object detection...
Clouds, Gravity and Metallicity in Blue L dwarfs: The Case of 2MASS J11263991-5003550 (2007)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Cruz, Kelle L., Swift, Brandon J.
Optical and near-infrared spectroscopy of the newly discovered peculiar L dwarf 2MASS J11263991-5003550 are presented. Folkes et al. identified this source as a high proper motion L9+/-1 dwarf based...
Looper, Dagny L., Burgasser, Adam J., Kirkpatrick, J. Davy, Swift, Brandon J.
We report the discovery of a fifth candidate substellar system in the ~5-10 Myr TW Hydrae Association - DENIS J124514.1-442907. This object has a NIR spectrum remarkably similar to that of 2MASS...
Plavchan, Peter, Jura, M., Kirkpatrick, J. Davy, Cutri, Roc M., Gallagher, S. C.
The 2MASS photometric calibration observations cover ~6 square degrees on the sky in 35 "calibration fields" each sampled in nominal photometric conditions between 562 and 3692 times during the four...
Looper, Dagny L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present the discovery of 11 new T dwarfs, found during the course of a photometric survey for mid-to-late T dwarfs in the 2MASS Point Source Catalog and from a proper-motion-selected sample of...
Looper, Dagny L., Kirkpatrick, J. Davy, Burgasser, Adam J.
We present the discovery of 11 new T dwarfs, found during the course of a photometric survey for mid-to-late T dwarfs in the 2MASS Point Source Catalog and from a proper motion selected sample of...
Outstanding Issues in Our Understanding of L, T, and Y Dwarfs (2007)
Since the discovery of the first L dwarf 19 years ago and the discovery of the first T dwarf 7 years after that, we have amassed a large list of these objects, now numbering almost six hundred....
A New Population of Young Brown Dwarfs (2007)
Cruz, Kelle L., Kirkpatrick, J. Davy, Burgasser, Adam J., Looper, Dagny, Mohanty, Subhanjoy, Prato, Lisa, ...
We report the discovery of a population of late-M and L field dwarfs with unusual optical and near-infrared spectral features that we attribute to low gravity -- likely uncommonly young, low-mass...
Cruz, Kelle L., Reid, I. Neill, Kirkpatrick, J. Davy, Burgasser, Adam J., Liebert, James, Solomon, Adam R., ...
We present a 20 pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey Second Incremental Release Point Source...
Moderate Resolution Spitzer Infrared Spectrograph (IRS) Observations of M, L, and T Dwarfs (2007)
Mainzer, A. K., Roellig, Thomas L., Saumon, D., Marley, Mark S., Cushing, Michael C., Sloan, G. C., ...
We present 10 - 19 um moderate resolution spectra of ten M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The IRS...
McLean, Ian S., Prato, L., McGovern, Mark R., Burgasser, Adam J., Kirkpatrick, J. Davy, Rice, Emily L., ...
We present a sequence of high resolution (R~20,000 or 15 km/s) infrared spectra of stars and brown dwarfs spanning spectral types M2.5 to T6. Observations of 16 objects were obtained using eight...
Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB (2006)
Burgasser, Adam J., Looper, Dagny L., Kirkpatrick, J. Davy, Liu, Michael C.
We report the discovery of the wide L1.5+L4.5 binary 2MASS J15200224-4422419AB, identified during spectroscopic followup of high proper motion sources selected from the Two Micron All Sky Survey....
Optical Spectroscopy of 2MASS Color-Selected Ultracool Subdwarfs (2006)
Burgasser, Adam J., Cruz, Kelle L., Kirkpatrick, J. Davy
We present Gemini GMOS and Magellan LDSS-3 optical spectroscopy for seven ultracool subdwarf candidates color-selected from the Two Micron All Sky Survey. Five are identified as late-type subdwarfs,...
Cruz, Kelle L., Reid, I. Neill, Kirkpatrick, J. Davy, Burgasser, Adam J., Liebert, James, Solomon, Adam R., ...
We present a 20-pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey (2MASS) Second Incremental Release Point...
A Sensitive Search for Variability in Late L Dwarfs: The Quest for Weather (2006)
Morales-Calderon, M., Stauffer, J. R., Kirkpatrick, J. Davy, Carey, S., Gelino, C. R., Navascues, D. Barrado Y, ...
We have conducted a photometric monitoring program of 3 field late-L brown dwarfs looking for evidence of non-axisymmetric structure or temporal variability in their photospheres. The observations...
Burgasser, Adam J., Kirkpatrick, J. Davy, Cruz, Kelle L., Reid, I. Neill, Leggett, Sandy K., Liebert, James, ...
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0"05-0"35, and companionship...
Discovery of the Coolest Extreme Subdwarf (2006)
Burgasser, Adam J., Kirkpatrick, J. Davy
We report the discovery of LEHPM 2-59 as the coolest extreme M subdwarf (esdM) found to date. Optical and near infrared spectroscopy demonstrate that this source is of later spectral type than the...
Adam J. Burgasser, J. Davy Kirkpatrick, Kelle L. Cruz, I. Neill Reid, Y K. Leggett, James Liebert, ...
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0B05Y0B35, and companionship...
Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574 (2005)
Kirkpatrick, J. Davy, Barman, Travis S., Burgasser, Adam J., McGovern, Mark R., McLean, Ian S., Tinney, Christopher G., ...
While following up L dwarf candidates selected photometrically from the Two Micron All Sky Survey, we uncovered an unusual object designated 2MASS J01415823-4633574. Its optical spectrum exhibits...
A Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs (2005)
Burgasser, Adam J., Burrows, Adam, Kirkpatrick, J. Davy
We present a method for measuring the physical parameters of the coldest T-type brown dwarfs using low resolution near infrared spectra. By comparing H_2O- and H_2-sensitive spectral ratios between...
SDSS J042348.57-041403.5AB: A Brown Dwarf Binary Straddling the L/T Transition (2005)
Burgasser, Adam J., Reid, I. Neill, Leggett, S. K., Kirkpatrick, J. Davy, Liebert, James, Burrows, Adam
We present the discovery of SDSS J042348.57-041403.5 as a closely-separated (0"16) brown dwarf binary, resolved by the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer....
A Unified Near Infrared Spectral Classification Scheme for T Dwarfs (2005)
Burgasser, Adam J., Geballe, T. R., Leggett, S. K., Kirkpatrick, J. Davy, Golimowski, David A.
A revised near infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser et al. and Geballe et al., and defined following the precepts of...
New spectral types L and T (2005)
The establishment of new spectral classes cooler than type M has had a brief, yet already rich, history. Prototypes of the new "L dwarf" and "T dwarf" classes were first found in the late 1980s to...
The 2MASS Wide-Field T Dwarf Search. V. Discovery of a T Dwarf via Methane Imaging (2005)
Ellis, S. C., Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W.
We present the discovery of a T dwarf, 2M2151-4853, via differential imaging through methane filters. The filters are designed to highlight the strong absorption in the H band, due to methane found...
The 2MASS Wide-Field T Dwarf Search. IV Unting out T dwarfs with Methane Imaging (2005)
Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W.
We present first results from a major program of methane filter photometry for low-mass stars and brown dwarfs. The definition of a new methane filter photometric system is described. A recipe is...
Multiplicity Amongst Wide Brown Dwarf Companions to Nearby Stars: Gliese 337CD (2005)
Burgasser, Adam J., Kirkpatrick, J. Davy, Lowrance, Patrick J.
We present Lick Natural Guide Star Adaptive Optics observations of the L8 brown dwarf Gliese 337C, which is resolved for the first time into two closely separated (0"53+/-0"03), nearly equal...
Patrick J. Lowrance, E. E. Becklin, Glenn Schneider, J. Davy Kirkpatrick, Alycia J. Weinberger, B. Zuckerman, ...
We have used the F160W filter (1.4–1.8 m) and the coronagraph on the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope to survey 45 single stars with a...
Burgasser, Adam J., Kirkpatrick, J. Davy, Lepine, Sebastien
Recent discoveries from red optical proper motion and wide-field near-infrared surveys have uncovered a new population of ultracool subdwarfs -- metal-poor stars and brown dwarfs extending into the...
The 2MASS Wide-Field T Dwarf Search. III. Seven New T Dwarfs and Other Cool Dwarf Discoveries (2004)
Burgasser, Adam J., McElwain, Michael W., Kirkpatrick, J. Davy, Cruz, Kelle L., Tinney, Chris G., Reid, I. Neill
We present the discovery of seven new T dwarfs identified in the Two Micron All Sky Survey. Low-resolution (R$\sim$150) 0.8--2.5 micron spectroscopy obtained with the IRTF SpeX instrument reveal the...
Vrba, F. J., Henden, A. A., Luginbuhl, C. B., Guetter, H. H., Munn, J. A., Canzian, B., ...
We present preliminary trigonometric parallaxes and proper motions for 22 L dwarfs and 18 T dwarfs measured using the ASTROCAM infrared imager. Relative to absolute parallax corrections are made by...
S Ori 70: Just a Foreground Field Brown Dwarf? (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, McGovern, Mark R., McLean, Ian S., Prato, L., Reid, I. Neill
We examine recent claims that the T-type brown dwarf S Ori 053810.1-023626 (S Ori 70) is a spectroscopically verified low mass (3$^{+5}_{-1}$ M$_{Jup}$) member of the 1--8 Myr $\sigma$ Orionis...
Identifying Young Brown Dwarfs Using Gravity-Sensitive Spectral Features (2003)
McGovern, Mark R., Kirkpatrick, J. Davy, McLean, Ian S., Burgasser, Adam J., Prato, L., Lowrance, Patrick J.
We report the initial results of the Brown Dwarf Spectroscopic Survey Gravity Project, to study gravity sensitive features as indicators of youth in brown dwarfs. Low-resolution (R~2000) J-band and...
The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low-Resolution Near-Infrared Spectra (2003)
McLean, Ian S., McGovern, Mark R., Burgasser, Adam J., Kirkpatrick, J. Davy, Prato, L., Kim, Sungsoo S.
We present the first results of a near-infrared (0.96-2.31 micron) spectroscopic survey of M, L, and T dwarfs obtained with NIRSPEC on the Keck II telescope. Our new survey has a resolving power of R...
Meeting the Cool New Neighbors V: A 2MASS-Selected Sample of Ultracool Dwarfs (2003)
Cruz, Kelle L., Reid, I. Neill, Liebert, James, Kirkpatrick, J. Davy, Lowrance, Patrick J.
We present initial results of our effort to create a statistically robust, volume-limited sample of ultracool dwarfs from the 2MASS Second Incremental Data Release. We are engaged in a multifaceted...
Burgasser, Adam J., McElwain, Michael W., Kirkpatrick, J. Davy
We present the discovery of three new Southern Hemisphere T dwarfs identified in the Two Micron All Sky Survey. These objects, 2MASS 0348-6022, 2MASS 0516-0445, and 2MASS 2228-4310, have...
The Spectra of T Dwarfs. II. Red Optical Data (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, Liebert, James, Burrows, Adam
We present 6300--10100 {\AA} spectra for a sample of 13 T dwarfs observed using LRIS mounted on the Keck I 10m Telescope. A variety of features are identified and analyzed, including...
Infrared Parallaxes for Methane T dwarfs (2003)
Tinney, C. G., Burgasser, Adam J., Kirkpatrick, J. Davy.
We report final results from our 2.5 year infrared parallax program carried out with the European Southern Observatory 3.5m New Technology Telescope and the SOFI infrared camera. Our program targeted...
The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics (2003)
Burgasser, Adam J., Kirkpatrick, J. Davy, Burrows, Adam, Liebert, James, Reid, I. Neill, Gizis, John E., ...
We present the discovery of the first L-type subdwarf, 2MASS J05325346+8246465. This object exhibits enhanced collision-induced H$_2$ absorption, resulting in blue NIR colors ($J-K_s =...
The Discovery of Two Nearby Carbon Dwarfs (2003)
Lowrance, Patrick J., Kirkpatrick, J. Davy, Reid, I. Neill, Cruz, Kelle L., Liebert, James
The comparison of optical and 2MASS near-infrared photometry for large samples of catalogued proper motion stars has the potential to discover previously unrecognized nearby objects of rare type. In...
Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope WPFC2 (2002)
Burgasser, Adam J., Kirkpatrick, J. Davy, Reid, I. Neill, Brown, Michael E., Miskey, Cherie L., Gizis, John E.
(abridged) We present the discovery of two T dwarf binaries, 2MASS 1225-2739AB and 2MASS 1534-2952AB, identified in a sample of ten T dwarfs imaged with the Hubble Space Telescope Wide Field...
The 2MASS Wide-Field T Dwarf Search. I. Discovery of a Bright T Dwarf Within 10 pc of the Sun (2002)
Burgasser, Adam J., Kirkpatrick, J. Davy, McElwain, Michael W., Cutri, Roc M., Burgasser, Albert J., Skrutskie, Michael F.
We present the discovery of a bright (J = 13.94$\pm$0.03) T dwarf, 2MASS 1503+2525, identified in a new, wide-field search for T dwarfs using the recently completed Two Micron All Sky Survey (2MASS)....
A Flaring L5 Dwarf: The Nature of H\alpha Emission in Very Low Mass (Sub)Stellar Objects (2002)
Liebert, James, Kirkpatrick, J. Davy, Cruz, K. L., Reid, I. Neill, Burgasser, Adam, Tinney, C. G., ...
Time series spectrophotometry of the L5 dwarf 2MASS 01443536-0716142 showed strong H\alpha emission which declined by nearly 75% in four consecutive exposures. The line was not detected in emission...
The Next Generation Sky Survey and the Quest for Cooler Brown Dwarfs (2002)
The Next Generation Sky Survey (NGSS) is a proposed NASA MIDEX mission to map the entire sky in four infrared bandpasses - 3.5, 4.7, 12, and 23 um. The seven-month mission will use a 50-cm telescope...
2MASS Data Mining and the M, L, and T Dwarf Archives (2002)
Studies of brown dwarfs as a distinct galactic population have been largely pioneered by dedicated, vast-area surveys at deep optical and near-infrared wavebands. The Two Micron All Sky Survey has,...
A Distant Stellar Companion in the Upsilon Andromedae System (2002)
Lowrance, Patrick J., Kirkpatrick, J. Davy, Beichman, Charles A.
Upsilon Andromedae is an F8V star known to have an extrasolar system of at least 3 planets in orbit around it. Here we report the discovery of a low-mass stellar companion to this system. The...
Evidence for Cloud Disruption in the L/T Dwarf Transition (2002)
Burgasser, Adam J., Marley, Mark S., Ackerman, Andrew S., Saumon, Didier, Lodders, Katharina, Dahn, Conard C., ...
Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because...
High resolution spectroscopy of ultracool M dwarfs (2002)
Reid, I. Neill, Kirkpatrick, J. Davy, Liebert, J., Gizis, J. E., Dahn, C. C., Monet, D. G.
(abridged) We present high-resolution echelle spectroscopy of a photometricaly-selected sample if thirty-nine dwarfs with spectral types between M6.5 and L0.5. Two stars, 2MASSI 0253202+271333 and...
A Search for Variability in the Active T dwarf 2MASS 1237+6526 (2002)
Burgasser, Adam J., Liebert, James, Kirkpatrick, J. Davy, Gizis, John E.
We present spectroscopic and imaging observations of the active T dwarf 2MASS 1237+6526, intended to investigate the emission mechanism of this cool brown dwarf. The H$\alpha$ emission line first...
Effective Temperatures of late L dwarfs and the onset of Methane signatures (2001)
Schweitzer, Andreas, Gizis, John E., Hauschildt, Peter H., Allard, France, Howard, Eric M., Kirkpatrick, J. Davy
We present a spectral analysis of a sample of late L dwarfs. We use our latest model atmospheres and synthetic spectra and optical and K band spectra to determine effective temperatures. We derive...
McLean, Ian S., Prato, L., Kim, Sungsoo S., Wilcox, M. K., Kirkpatrick, J. Davy, Burgasser, Adam
We report the possible identification of weak methane spectral features in the near-infrared K band in two late L dwarfs, DENIS 0205-11 (L7) and 2MASS 1523+30 (L8). New, high signal-to-noise ratio...
Theoretical Spectral Models of T Dwarfs at Short Wavelengths and Their Comparison with Data (2001)
Burrows, Adam, Burgasser, Adam J., Kirkpatrick, J. Davy, Liebert, James, Milsom, J. A., Sudarsky, David, ...
We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600 K to 1300 K thought to encompass the known T dwarfs. For the first time, theoretical...
The Spectra of T Dwarfs I: Near-Infrared Data and Spectral Classification (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy, Brown, Michael E., Reid, I. Neill, Burrows, Adam, Liebert, James, ...
We present near-infrared spectra for a sample of T dwarfs, including eleven new discoveries made using the Two Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs...
Wilson, J. C., Kirkpatrick, J. Davy, Gizis, J. E., Skrutskie, M. F., Monet, D. G., Houck, J. R.
We present two confirmed wide separation L-dwarf common proper motion companions to nearby stars and one candidate identified from the Two Micron All Sky Survey. Spectral types from optical...
Three newly-discovered M-dwarf companions of Solar Neighbourhood stars (2001)
Kirkpatrick, J. Davy, Liebert, James, Cruz, K. L., Gizis, J. E., Reid, I. Neill
We present low-resolution spectroscopy of newly-discovered candidate companions to three stars in the Solar Neighbourhood. All three companions are M dwarfs, with spectral types ranging from M4 to...
Brown Dwarf Companions to G-type Stars. I: Gliese 417B and Gliese 584C (2001)
Kirkpatrick, J. Davy, Dahn, Conard C., Monet, David G., Reid, I. Neill, Gizis, John E., Liebert, James, ...
We present astrometric and spectroscopic observations confirming that two nearby G dwarf systems (Gliese 417 = BD+36 2162 and Gliese 584AB = eta CrB AB) have a widely separated, L dwarf, substellar...
Substellar Companions to Main Sequence Stars: No Brown Dwarf Desert at Wide Separations (2001)
Gizis, John E., Kirkpatrick, J. Davy, Burgasser, Adam, Reid, I. Neill, Monet, David G., Liebert, James, ...
We use three field L and T dwarfs which were discovered to be wide companions to known stars by the Two Micron All-Sky Survey (2MASS) to derive a preliminary brown dwarf companion frequency. Observed...
The Classification of T Dwarfs (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy, Brown, Michael E.
We discuss methods for classifying T dwarfs based on spectral morphological features and indices. T dwarfs are brown dwarfs which exhibit methane absorption bands at 1.6 and 2.2 ${\mu}m$. Spectra at...
Optical Spectroscopy of T Dwarfs (2001)
Burgasser, Adam J., Kirkpatrick, J. Davy
Optical spectra are presented for a sample of T dwarfs, obtained using the Keck 10m Low Resolution Imaging Spectrograph. Dominant features are discussed, including possible temperature diagnostics.
A 2MASS L Dwarf Companion to the Nearby K Dwarf GJ 1048 (2000)
Gizis, John E., Kirkpatrick, J. Davy, Wilson, John C.
We report the discovery of a probable L1 companion to the nearby K2 dwarf GJ 1048 using the Two Micron All-Sky Survey (2MASS). This source, 2MASSI J0235599-233120 or GJ 1048B, has 2MASS near-infrared...
Near-Infrared Spectral Classification of late-M and L Dwarfs (2000)
Reid, I. Neill, Burgasser, A. J., Cruz, K. L., Kirkpatrick, J. Davy, Gizis, J. E.
We present near-infrared (1 to 2.5 micron) low-resolution spectroscopy of eleven ultracool dwarfs with spectral types ranging from M7 to L8. Combining our observations with data published previously...
A search for L dwarf binary systems (2000)
Reid, I. Neill, Gizis, John E., Kirkpatrick, J. Davy, Koerner, D. W.
We present analysis of HST Planetary Camera images of twenty L dwarfs identified in the course of the Two Micron All-Sky Survey. Four of the targets have faint, red companions at separations between...
Hurt, Robert L., Jarrett, Tom H., Kirkpatrick, J. Davy, Cutri, Roc M., Schneider, Stephen E., Skrutskie, Mike, ...
We present the basic properties of three objects near the Galactic Plane - a large galaxy and two candidate globular clusters - discovered in the Two Micron All Sky Survey (2MASS) dataset. All were...
New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence (2000)
Gizis, John E., Monet, David G., Reid, I. Neill, Kirkpatrick, J. Davy, Liebert, James, Williams, Rik J.
We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with K_s6 Angstroms) ultracool M dwarfs are consistent with an ordinary old disk stellar population,...
Discovery of a Bright Field Methane (T-type) Brown Dwarf by 2MASS (2000)
Burgasser, Adam J., Wilson, John C., Kirkpatrick, J. Davy, Skrutskie, Michael F., Colonno, Michael R., Enos, Alan T., ...
We report the discovery of a bright (J = 13.83$\pm$0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by...
Sixty-seven Additional L Dwarfs Discovered by the Two Micron All Sky Survey (2MASS) (2000)
Kirkpatrick, J. Davy, Reid, I. Neill, Liebert, James, Gizis, John E., Burgasser, Adam J., Monet, David G., ...
We present JHKs photometry, far red spectra, and spectral classifications for an additional 67 L dwarfs discovered by the Two Micron All Sky Survey. One of the goals of this new search was to locate...
Detection of H Alpha Emission in a Methane (T-Type) Brown Dwarf (2000)
Burgasser, Adam J., Kirkpatrick, J. Davy, Reid, I. Neill, Liebert, James, Gizis, John E., Brown, Michael E.
We report the detection of H{$\alpha$} emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux,...
An Improved Red Spectrum of the Methane or T-dwarf SDSS 1624+0029: Role of the Alkali Metals (2000)
Liebert, James, Reid, I. Neill, Burrows, Adam, Burgasser, Adam J., Kirkpatrick, J. Davy, Gizis, John E.
A Keck~II low resolution spectrum shortward of ome-micron is presented for SDSS 1624+0029, the first field methane or T dwarf discovered in the Sloan Digital Sky Survey. Significant flux is detected...
J-Band Infrared Spectroscopy of a Sample of Brown Dwarfs Using Nirspec on Keck II (2000)
McLean, Ian S., Wilcox, Mavourneen K., Becklin, E. E., Figer, Donald F., Gilbert, Andrea M., Graham, James R., ...
Near-infrared spectroscopic observations of a sample of very cool, low-mass objects are presented with higher spectral resolution than in any previous studies. Six of the objects are L-dwarfs,...
A Keck/HST Survey for Companions to Low-Luminosity Dwarfs (1999)
Koerner, D. W., Kirkpatrick, J. Davy, Reid, I. N., Gizis, J.
We present preliminary results of an imaging survey for companions to low-luminosity dwarfs with spectral types ranging from M7 to L9. A K-band study with the Near Infrared Camera (NIRC) at the Keck...
Keck Imaging of Binary L Dwarfs (1999)
Koerner, D. W., Kirkpatrick, J. Davy, McElwain, M. W., Bonaventura, N. R.
We present Keck near-infrared imaging of three binary L dwarf systems, all of which are likely to be sub-stellar. Two are lithium dwarfs, and a third exhibits an L7 spectral type, making it the...
Reid, I. Neill, Kirkpatrick, J. Davy, Gizis, J. E., Dahn, C. C., Monet, D. G., Williams, R. J., ...
We present spectroscopic, photometric and astrometric observations of four bright L dwarfs identified in the course of the 2MASS near-infrared survey. Our spectroscopic data extend to wavelengths...
Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, John E. Gizis, Conard C. Dahn, ...
We report the discovery of four field methane (“T”-type) brown dwarfs using Two Micron All-Sky Survey (2MASS) data. One additional methane dwarf, previously discovered by the Sloan Digital Sky...
Stauffer, John, Schultz, Greg, Kirkpatrick, J. Davy
We have obtained intermediate resolution spectra of eleven candidate brown dwarf members of the Pleiades open cluster using the Keck II telescope and LRIS spectrograph. Our primary goal was to...