J/ApJ/924/114 Beyond the local volume. I. HST ultracool dwarfs (Aganze+, 2022)
Beyond the local volume.
I. Surface densities of ultracool dwarfs in deep HST/WFC3 parallel fields.
Aganze C., Burgasser A.J., Malkan M., Theissen C.A., Tejada Arevalo R.A.,
Hsu C.-C., Bardalez Gagliuffi D.C., Ryan R.E., Holwerda B.
<Astrophys. J., 924, 114 (2022)>
=2022ApJ...924..114A 2022ApJ...924..114A
ADC_Keywords: Photometry, HST; Spectra, optical; Spectral types;
Stars, distances; Stars, L-type; Stars, T-type; Stars, M-type;
Stars, brown dwarf; Infrared sources; Surveys
Keywords: Brown dwarfs ; T dwarfs ; Random Forests ; Neural networks ;
L dwarfs ; M dwarf stars
Abstract:
Ultracool dwarf stars and brown dwarfs provide a unique probe of
large-scale Galactic structure and evolution; however, until recently
spectroscopic samples of sufficient size, depth, and fidelity have
been unavailable. Here, we present the identification of 164 M7-T9
ultracool dwarfs in 0.6deg2 of deep, low-resolution, near-infrared
spectroscopic data obtained with the Hubble Space Telescope (HST) Wide
Field Camera 3 (WFC3) instrument as part of the WFC3 Infrared
Spectroscopic Parallel Survey and the 3D-HST survey. We describe the
methodology by which we isolate ultracool dwarf candidates from over
200000 spectra, and show that selection by machine-learning
classification is superior to spectral index-based methods in terms of
completeness and contamination. We use the spectra to accurately
determine classifications and spectrophotometric distances, the latter
reaching to ∼2kpc for L dwarfs and ∼400pc for T dwarfs.
Description:
In this paper, we present a new analysis of HST/WFC3 slitless grism
spectra from the WFC3 Infrared Spectroscopic Parallel Survey (WISPS;
Atek+ 2010ApJ...723..104A 2010ApJ...723..104A) and 3D-HST (Momcheva+ 2016, J/ApJS/225/27 ;
Brammer+ 2012ApJS..200...13B 2012ApJS..200...13B & Skelton+ 2014, J/ApJS/214/24) survey,
expanding both the areal coverage and spectral types evaluated in
these deep spectroscopic data sets.
The WISPS and 3D-HST surveys used the infrared channel of the WFC3
camera, obtaining low-resolution G102 (λ=0.8-1.17um,
λ/Δλ∼200) and G141 (λ=1.11-1.67um,
λ/Δλ∼130) grism spectra. See Section 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 120 128 Late M dwarfs identified in WISPS and 3D-HST data
table4.dat 120 36 L and T dwarfs identified in WISPS and 3D-HST data
table11.dat 128 78 *Additional late-type M dwarfs identified in WISPS
and 3D-HST data
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Note on table11.dat: Additional Ultracool dwarfs (UCDs; M≲0.1M☉,
Teff≲3000K) candidates that were classified earlier than spectral
type M7 based on comparison to spectral standards, but matched to high
S/N UCD spectral templates classified M7 or later (Section 3.1). These
sources were not included in the main sample, but are likely to be
mid- to late-M dwarfs.
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/261 : GOODS initial results (Giavalisco+, 2004)
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/126/1526 : IR photometry of ultracool dwarfs (Bouy+, 2003)
J/MNRAS/358/13 : Faint dwarfs in NGC 2547 (Jeffries+, 2005)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/ApJ/637/1067 : NIR spectral classification of T dwarfs (Burgasser+, 2006)
J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)
J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008)
J/ApJ/695/1591 : Spectrophotometry in PEARS fields (Pirzkal+, 2009)
J/ApJS/190/100 : NIR proper motion survey using 2MASS (Kirkpatrick+, 2010)
J/A+A/522/A112 : i'z' phot. of L5 and later dwarf candidates (Reyle+, 2010)
J/MNRAS/414/2602 : Automated classification of HIP variables (Dubath+, 2011)
J/ApJS/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/ApJ/769/80 : Spitzer/IRAC observations of five deep fields (Ashby+, 2013)
J/ApJ/788/77 : MW L/T/M-dwarfs identified in BoRG survey (Holwerda+, 2014)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
J/ApJS/225/27 : 3D-HST Survey: grism sp. master catalog (Momcheva+, 2016)
J/A+A/598/A92 : New ultracool subdwarfs (Lodieu+, 2017)
J/MNRAS/465/3203 : GALAH observational overview (Martell+, 2017)
J/ApJS/234/1 : M, L, & T dwarfs from PS1 3π Survey (Best+, 2018)
J/MNRAS/489/5301 : DES Y3 substellar LT and M catalogs (Carnero Rosell+, 2019)
J/AJ/158/75 : Mid-type M dwarfs with planets (Hardegree-Ullman+, 2019)
J/ApJS/240/19 : Parallaxes of late-T and Y dwarfs (Kirkpatrick+, 2019)
J/AJ/157/101 : Cloud Atlas: HST/WFC3 NIR sp. library (Manjavacas+, 2019)
J/ApJ/898/77 : NIR spectra of 2 extreme T-type subdwarfs (Schneider+, 2020)
J/ApJS/253/7 : A full-sky census of BDs within 20pc (Kirkpatrick+, 2021)
http://archive.stsci.edu/prepds/wisp/ : The WISP Survey on MAST
Byte-by-byte Description of file: table[34].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- ID Designation (JHHMMSSss+DDMMSSs)
19- 38 A20 --- Field Field identifier
40- 45 F6.3 mag F110W [18.68/24.4]? HST/WFC3 F110W apparent AB
magnitude
47- 51 F5.3 mag e_F110W [0.001/0.2]? Uncertainty in F110W
53- 58 F6.3 mag F140W [16.69/24.6]? HST/WFC3 F140W apparent AB
magnitude
60- 64 F5.3 mag e_F140W [0.001/0.07]? Uncertainty in F140W
66- 71 F6.3 mag F160W [15.74/25]? HST/WFC3 F160W apparent AB
magnitude
73- 77 F5.3 mag e_F160W [0/0.3]? Uncertainty in F160W
79- 81 I3 --- SNR [3/518] Signal-to-Noise in the J-band continuum
83- 86 A4 --- SpT Spectral type
88- 90 F3.1 --- e_SpT [0.5/9.3] Uncertainty in SpT
92- 95 I4 pc Dist [49/3145] Distance
97- 104 I8 pc E_Dist [13/50000000] Upper uncertainty in Dist
106- 109 I4 pc e_Dist [10/1168] Lower uncertainty in Dist
111- 120 A10 --- Sel Selection method (s) (G1)
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Byte-by-byte Description of file: table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- ID Designation (JHHMMSSss+DDMMSSs)
19- 38 A20 --- Field Field identifier
40- 45 F6.3 mag F110W [18.3/23.6]? HST/WFC3 F110W apparent AB magnitude
47- 51 F5.3 mag e_F110W [0.001/0.02]? Uncertainty in F110W
53- 58 F6.3 mag F140W [17.27/23]? HST/WFC3 F140W apparent AB magnitude
60- 64 F5.3 mag e_F140W [0/0.04]? Uncertainty in F140W
66- 71 F6.3 mag F160W [16.6/23.2]? HST/WFC3 F160W apparent AB magnitude
73- 77 F5.3 mag e_F160W [0/0.04]? Uncertainty in F160W
79- 81 I3 --- SNR [3/403] Signal-to-Noise in the J-band continuum
83- 86 A4 --- SpT Adopted spectral type
88- 90 F3.1 --- e_SpT [0.5/3] Uncertainty in SpT
92- 96 A5 --- SpTSS Spectral type by using spectral standards
98- 100 F3.1 --- e_SpTSS [0.5/7.3] Uncertainty in SpTSS
102- 105 I4 pc Dist [120/2286] Distance
107- 109 I3 pc E_Dist [36/942] Upper uncertainty in Dist
111- 113 I3 pc e_Dist [30/548] Lower uncertainty in Dist
115- 128 A14 --- Sel Selection method (s) (G1)
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Global notes:
Note (G1): Selection method as follows:
IND = Index-Index selection;
RF = Random Forest selection;
DNN = Deep Neural Network.
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History:
From electronic version of the journal
References:
Aganze et al. Paper II. 2022ApJ...934...73A 2022ApJ...934...73A
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Aug-2023