J/ApJS/219/33 BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
BANYAN.
VII. A new population of young substellar candidate members of nearby moving
groups from the BASS survey.
Gagne J., Faherty J.K., Cruz K.L., Lafreniere D., Doyon R., Malo L.,
Burgasser A.J., Naud M.-E., Artigau E., Bouchard S., Gizis J.E., Albert L.
<Astrophys. J. Suppl. Ser., 219, 33 (2015)>
=2015ApJS..219...33G 2015ApJS..219...33G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Spectra, infrared ; Spectral types ;
Stars, ages ; Stars, masses ; Stars, diameters ;
Effective temperatures ; Surveys
Keywords: brown dwarfs; methods: data analysis; proper motions;
stars: kinematics and dynamics; stars: low-mass
Abstract:
We present the results of a near-infrared (NIR) spectroscopic
follow-up survey of 182 M4-L7 low-mass stars and brown dwarfs (BDs)
from the BANYAN All-Sky Survey (BASS) for candidate members of nearby,
young moving groups (YMGs). We confirm signs of low gravity for 42 new
BD discoveries with estimated masses between 8 and 75MJup and
identify previously unrecognized signs of low gravity for 24 known
BDs. We refine the fraction of low-gravity dwarfs in the
high-probability BASS sample to ∼82%. We use this unique sample of 66
young BDs, supplemented with 22 young BDs from the literature, to
construct new empirical NIR absolute magnitude and color sequences for
low-gravity BDs. We show that low-resolution NIR spectroscopy alone
cannot differentiate between the ages of YMGs younger than ∼120Myr,
and that the BT-Settl atmosphere models do not reproduce well the dust
clouds in field or low-gravity L-type dwarfs. We obtain a
spectroscopic confirmation of low gravity for 2MASS J14252798-3650229,
which is a new ∼27MJup, L4 γ bona fide member of AB Doradus.
We identify a total of 19 new low-gravity candidate members of YMGs
with estimated masses below 13MJup, 7 of which have kinematically
estimated distances within 40pc. These objects will be valuable
benchmarks for a detailed atmospheric characterization of
planetary-mass objects with the next generation of instruments. We
find 16 strong candidate members of the Tucana-Horologium association
with estimated masses between 12.5 and 14MJup, a regime where our
study was particularly sensitive. This would indicate that for this
association there is at least one isolated object in this mass range
for every 17.5-5.0+6.6 main-sequence stellar member, a number
significantly higher than expected based on standard log-normal
initial mass function, however, in the absence of radial velocity and
parallax measurements for all of them, it is likely that this
over-density is caused by a number of young interlopers from other
associations.
Description:
We obtained low-resolution NIR spectra of 241 candidate young moving
group (YMG) members from the BANYAN All-Sky Survey (BASS), LP-BASS,
and PRE-BASS samples. A description of individual observations is
included in Table 1.
There are three samples that are referred to in this Paper:
(1) PRE-BASS consists of targets that were initially selected as
potential members and followed up with spectroscopy, but that were
later rejected as we modified our selection criteria to reject
contaminants;
(2) Low-Priority BASS (LP-BASS) consists of targets that have NIR
colors only slightly redder than field dwarfs; and
(3) BASS is the final sample presented in Paper V (Gagne et al., 2015,
J/ApJ/798/73) that contains targets at least 1σ redder than
field dwarfs and that has a lower fraction of contaminants.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 102 227 Observing log of candidate members
table4.dat 156 264 Spectral classification, low gravity, and
young moving group (YMG) membership
table5.dat 126 81 Equivalent widths and spectral indices
table8.dat 104 276 Physical parameters
table9.dat 80 20 Potential isolated planetary-mass objects
refs.dat 68 63 References
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/149/158 : The BUD sample. I. L dwarf activity sample (Schmidt+, 2015)
J/MNRAS/447/1267 : Low-mass members of the Octans association (Murphy+, 2015)
J/ApJ/798/73 : BANYAN All-Sky Survey (BASS). V. Nearby YMGs (Gagne+, 2015)
J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)
J/ApJ/786/29 : Catalog of distances to molecular clouds (Schlafly+, 2014)
J/AJ/147/94 : Solar neighborhood. XXXII. L and M dwarfs (Dieterich+, 2014)
J/A+A/564/A55 : 1.1-2.4um spectra of 7 young M & L dwarfs (Manjavacas+, 2014)
J/ApJ/783/121 : BANYAN II. Nearby young assoc. cand. members (Gagne+, 2014)
J/AJ/147/34 : SpeX library of L-type dwarfs (Schneider+, 2014)
J/ApJ/777/160 : NIR survey for planets around MG stars (Biller+, 2013)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/PASP/125/809 : New nearby M, L, and T dwarfs (Thompson+, 2013)
J/MNRAS/433/457 : 76 T dwarfs from the UKIDSS LAS (Burningham+, 2013)
J/ApJS/205/6 : T dwarf population revealed by WISE (Mace+, 2013)
J/ApJ/762/88 : Young stellar kinematic group candidate members (Malo+, 2013)
J/ApJ/758/56 : Young M dwarfs within 25pc. II. Kinematics (Shkolnik+, 2012)
J/AJ/144/99 : Near-IR spectroscopy of 36 late M dwarfs (Deshpande+, 2012)
J/ApJ/753/156 : T/Y brown dwarfs with WISE photometry (Kirkpatrick+, 2012)
J/AJ/143/80 : Low-mass stars of beta Pic & AB Dor groups (Schlieder+, 2012)
J/ApJ/723/684 : NIRSPEC ultracool dwarf radial velocity survey (Blake+, 2010)
J/AJ/139/1808 : Colors and kinematics of SDSS L dwarfs (Schmidt+, 2010)
J/A+A/512/A37 : Velocities of 43 nearby L dwarfs (Seifahrt+, 2010)
J/ApJ/710/1142 : SpeX spectroscopy of low mass binaries. I. (Burgasser+, 2010)
J/ApJ/705/1416 : Volume-limited sample of M7-M9.5 dwarfs (Reiners+, 2009)
J/ApJ/689/1295 : Lithium test implications for BD* (Kirkpatrick+, 2008)
J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/MNRAS/383/831 : New DENIS nearby L and late-M dwarfs (Phan-Bao+, 2008)
J/AJ/133/2258 : Activity and kinematics of ultracool dwarfs (Schmidt+, 2007)
J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)
J/ApJ/637/1067 : NIR spectral classification of T dwarfs (Burgasser+, 2006)
J/AJ/130/1871 : Spectroscopic survey of M dwarfs (Bochanski+, 2005)
J/A+A/430/165 : Radial velocities for 6691 K and M giants (Famaey+, 2005)
J/AJ/127/3553 : JHK photometry & spectro. for L and T dwarfs (Knapp+, 2004)
J/AJ/126/3007 : Spectroscopy of faint red NLTT dwarfs (Reid+, 2003)
J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)
J/AJ/125/3302 : HST binary very low mass stars & brown dwarfs (Gizis+, 2003)
http://www.dwarfarchives.org/ : DwarfArchives.org home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- S Survey (S= BASS or LP-BASS; p=PRE-BASS)
3- 18 A16 --- 2MASS 2MASS designation HHMMSSss+DDMMSSs; J2000
20- 24 A5 --- m_2MASS 2MASS components
26- 30 F5.2 mag Jmag [9/17.1] 2MASS J-band magnitude
32- 42 A11 "YYYY/MMM/DD" Date Observation date
44- 54 A11 "YYYY/MMM/DD" Date2 Second date of observation
55 A1 --- --- [,]
56- 57 I2 --- Date3 ? Third date of observation (day)
59- 70 A12 --- Tel Telescope
72- 82 A11 --- Inst Instrument
84- 88 F5.3 arcsec Slit [0.5/1] Slit width
90- 93 I4 --- Res [90/6000] Resolving power
95- 99 I5 s Exp [120/16000] Total exposure time
101-102 I2 --- N [1/64] Number of exposures
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Mm Member description code (1)
3- 18 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs; J2000)
20 A1 --- m_2MASS 2MASS component
22- 26 F5.2 mag Jmag [8.3/17.1] 2MASS J band magnitude
28- 36 A9 --- SpT-OL Optical MK spectral type from literature (2)
38- 42 A5 --- r_SpT-OL Reference(s) for SpType-OL (see refs.dat file)
44- 52 A9 --- SpT-NL NIR MK spectral type from literature (2)
54- 55 A2 --- r_SpT-NL Reference(s) for SpType-NL (see refs.dat file)
57- 60 A4 --- SpT-H2O MK spectral type from H2O indices
62- 78 A17 --- SpT Adopted MK spectral type
80- 84 A5 --- Class Index-based gravity class (3)
86- 89 A4 --- Score Index-based gravity score (3)
91- 98 A8 --- Mm-L YMG membership from the literature (G1)
100-103 A4 --- r_Mm-L Reference(s) for Mem-L (see refs.dat file)
105-130 A26 --- Mm-U Updated BASS YMG membership (G1)(4)
132 A1 --- l_BP Limit flag on BP
134-138 F5.1 % BP ? Bayesian probability for YMG membership
140 A1 --- l_CP Limit flag on CP
142-145 F4.1 % CP ? Probability object is a field contaminant (5)
147-154 A8 --- Cat Source catalog
156 A1 --- f_Cat [f] f = Low-probability Sample
--------------------------------------------------------------------------------
Note (1): Code as follows:
1 = Bona Fide Member;
2 = Low-Gravity Candidate Member;
3 = Candidate Member with no Constraint on Surface Gravity;
4 = Field Contaminant;
5 = Young Contaminant;
6 = Reddened Contaminant.
Note (2): All spectral types determined in this work are based on NIR spectra,
except those with the o suffix, which are based on optical data. A
semi-colon in the optical and NIR spectral types indicates that the
subtype is uncertain (±1), and a double semi-colon indicates
that the subtype is very uncertain (±2 subtypes or more);
pec indicates peculiar features; β and γ respectively
indicate intermediate gravity and very low gravity, determined
from a visual classification.
Note (3): The index-based gravity classes and scores are defined by
Allers & Liu (2013ApJ...772...79A 2013ApJ...772...79A) and based on the FeH and VO
features, alkali lines depth and the H-band continuum shape,
respectively. We used our adopted spectral subtypes in their
calculation. A score value of 0 indicates field gravity,
1 indicates intermediate gravity and 2 indicates a very low gravity.
A score of n indicates that no conclusion can be drawn either because
the spectroscopic indicator in question is not sensitive to gravity
at this spectral type or because the data does not cover the
wavelength of this index. A question mark indicates that the quality
of the data is not good enough to draw any conclusion (i.e., the
measurement is consistent with low gravity, but the measurement error
bar overlaps with the field sequence). The final gravity score is
taken as the median of these individual gravity scores, ignoring n
or ? scores and taking the average of the two central values when an
even number of scores is used.
Note (4): Results reported in the BASS survey paper (Paper V, Gagne et al.,
2015, J/ApJ/798/73), updated using data presented here.
Note (5): Based on a Monte Carlo analysis and the Besancon galactic
model (see text and Paper II, Gagne et al., 2014, J/ApJ/783/121).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- G i=intermediate gravity (β) or
l=very low-gravity (γ or δ)
3- 18 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs; J2000)
20 A1 --- m_2MASS 2MASS component
22- 34 A13 --- SpT MK spectral type
36- 39 F4.1 0.1nm EWNaI [3.7/12.8]? NaI 1.138um equivalent width (Å)
41- 43 F3.1 0.1nm e_EWNaI [0.1/2.5]? EWNaI uncertainty
45- 48 F4.1 0.1nm EWKI1 [-0.4/6.8]? KI 1.169um equivalent width (Å)
50- 52 F3.1 0.1nm e_EWKI1 [0.2/2]? EWKI1 uncertainty
54- 56 F3.1 0.1nm EWKI2 [0.5/8.8]? KI 1.177um equivalent width (Å)
58- 60 F3.1 0.1nm e_EWKI2 [0.1/2.1]? EWKI2 uncertainty
62- 64 F3.1 0.1nm EWKI3 [0.2/6.7]? KI 1.244um equivalent width (Å)
66- 68 F3.1 0.1nm e_EWKI3 [0.2/3.8]? EWKI3 uncertainty
70- 72 F3.1 0.1nm EWKI4 [0.4/5.6]? KI 1.253um equivalent width (Å)
74- 76 F3.1 0.1nm e_EWKI4 [0.1/2.1]? EWKI4 uncertainty
78- 81 F4.2 --- FeHz [0.9/1.3]? FeHz spectral index (1)
83- 86 F4.2 --- e_FeHz [0.01/0.2]? FeHz uncertainty
88- 91 F4.2 --- VOz [0.9/1.4] VOz spectral index (1)
93- 96 F4.2 --- e_VOz [0.01/0.05] VOz uncertainty
98-101 F4.2 --- FeHJ [1/1.3]? FeHJ spectral index (1)
103-106 F4.2 --- e_FeHJ [0.01/0.04]? FeHJ uncertainty
108-111 F4.2 --- KIJ [1/1.2]? KIJ spectral index (1)
113-116 F4.2 --- e_KIJ [0.01/0.04]? KIJ uncertainty
118-121 F4.2 --- Hc [0.9/1.1]? H-cont spectral index (1)
123-126 F4.2 --- e_Hc [0.01/0.02]? Hc uncertainty
--------------------------------------------------------------------------------
Note (1): See Allers and Liu, 2013ApJ...772...79A 2013ApJ...772...79A
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Type Object description
13- 28 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs; J2000)
30 A1 --- m_2MASS 2MASS component
32- 48 A17 --- SpT MK spectral type
50- 52 I3 Myr AgeLo [5/110]? Lower YMG age range (1)
54- 56 I3 Myr AgeHi [15/500]? Upper YMG age range (1)
58- 62 F5.1 Mjup Mass [6.5/189.1]? Estimated mass (2)
64- 67 F4.1 Mjup E_Mass ? Upper limit uncertainty in Mass
69- 72 F4.1 Mjup e_Mass ? Lower limit uncertainty in Mass
74- 77 F4.2 Rjup Rad [0.8/4.4]? Estimated radius
79- 82 F4.2 Rjup E_Rad ? Upper limit uncertainty in Rad
84- 87 F4.2 Rjup e_Rad ? Lower limit uncertainty in Rad
89- 92 I4 K Teff [1200/3100]? Estimated effective
temperature (3)
94- 96 I3 K e_Teff ? Uncertainty in Teff
98-100 F3.1 [cm/s2] log(g) [3/5.5]? Estimated log surface gravity (4)
102-104 F3.1 [cm/s2] e_log(g) ? Uncertainty in log(g)
--------------------------------------------------------------------------------
Note (1): A single YMG age value in the AgeHi column indicates
an approximate age.
Note (2): Estimated masses and radii were derived from a comparison of the
trigonometric or statistical distances, the age of the most probable
YMG membership and the 2MASS and WISE photometry with AMES-Cond
evolutionary models (see the text for a detailed explanation).
Note (3): Obtained from the modified model fitting that uses WISE W 1, W 2
photometry as well as NIR spectra in the J, H and K bands.
Note (4): Obtained from a weighted mean of H-band and K-band log(g)
(see text for more information).
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs; J2000)
18 I1 --- Ref [1/8] Reference (1)
20- 33 A14 --- SpT MK spectral type
35- 42 A8 --- Sample Source sample
44- 50 A7 --- YMG Moving group (G1)
52- 55 F4.1 Mjup Mass [6.5/13] Estimated mass
57- 59 F3.1 Mjup E_Mass [0.3/1.4] Positive error on Mass
61- 63 F3.1 Mjup e_Mass [0.4/2] Negative error on Mass
65- 69 F5.2 pc Dist [7/81] Kinematic distance (2)
71- 74 F4.2 pc E_Dist [2/9] Positive error on Dist
76- 79 F4.2 pc e_Dist [2/8] Negative error on Dist
80 A1 --- f_Dist [b] b: Trigonometric distance
--------------------------------------------------------------------------------
Note (1): Reference as follows:
1 = Kirkpatrick et al. (2000AJ....120..447K 2000AJ....120..447K),
2 = This paper,
3 = Reid et al. (2008, J/AJ/136/1290),
4 = Cruz et al. (2007AJ....133..439C 2007AJ....133..439C),
5 = Cruz et al. (2003, J/AJ/126/2421),
6 = Gagne et al. (2014ApJ...785L..14G 2014ApJ...785L..14G),
7 = Chiu et al. (2006, J/AJ/131/2722),
8 = Gagne et al. (2014ApJ...792L..17G 2014ApJ...792L..17G).
Note (2): Kinematic distances estimated from moving group membership
unless noted.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode Bibcode
24- 48 A25 --- Aut Author's name(s)
50- 68 A19 --- Comm Catalog's reference in VizieR
--------------------------------------------------------------------------------
Global note:
Note (G1): Young moving group as follows:
TWA = TW Hydrae association (de La Reza et al. 1989ApJ...343L..61D 1989ApJ...343L..61D;
Kastner et al. 1997Sci...277...67K 1997Sci...277...67K; Zuckerman & Song 2004,
J/other/ARA+A/42.685; 5-15 Myr;
Weinberger et al. 2013ApJ...762..118W 2013ApJ...762..118W)
BPMG = β Pictoris (Zuckerman et al. 2001ApJ...562L..87Z 2001ApJ...562L..87Z; 20-26 Myr;
Mamajek & Bell 2014MNRAS.445.2169M 2014MNRAS.445.2169M; Malo et al. 2014ApJ...792...37M 2014ApJ...792...37M;
Binks & Jeffries 2014MNRAS.438L..11B 2014MNRAS.438L..11B)
CAR = Carina (20-40 Myr; Torres et al. 2008hsf2.book..757T 2008hsf2.book..757T)
COL = Columba (20-40 Myr; Torres et al. 2008hsf2.book..757T 2008hsf2.book..757T)
THA = Tucana-Horologium (Torres et al. 2000AJ....120.1410T 2000AJ....120.1410T;
Zuckerman & Webb 2000ApJ...535..959Z 2000ApJ...535..959Z; 20-40 Myr;
Kraus et al. 2014, J/AJ/147/146)
ARG = Argus (30-50 Myr; Makarov & Urban 2000MNRAS.317..289M 2000MNRAS.317..289M)
ABDMG = AB Doradus (Zuckerman et al. 2004ApJ...613L..65Z 2004ApJ...613L..65Z; 110-130 Myr;
Luhman et al. 2005ApJ...628L..69L 2005ApJ...628L..69L;
Barenfeld et al. 2013ApJ...766....6B 2013ApJ...766....6B)
Pleiades = ∼120Myr; Cruz et al. 2009AJ....137.3345C 2009AJ....137.3345C;
Allers & Liu 2013ApJ...772...79A 2013ApJ...772...79A
UMA = Ursa Majoris moving group (∼300Myr; Zuckerman & Song 2004,
J/other/ARA+A/42.685)
SCC = Scorpius-Centaurus Complex
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Malo et al. Paper I. 2013ApJ...762...88M 2013ApJ...762...88M Cat. J/ApJ/762/88
Gagne et al. Paper II. 2014ApJ...783..121G 2014ApJ...783..121G Cat. J/ApJ/783/121
Malo et al. Paper III. 2014ApJ...788...81M 2014ApJ...788...81M Cat. J/ApJ/788/81
Malo et al. Paper IV. 2014ApJ...792...37M 2014ApJ...792...37M
Gagne et al. Paper V. 2015ApJ...798...73G 2015ApJ...798...73G Cat. J/ApJ/798/73
Artigau et al. Paper VI. 2015ApJ...806..254A 2015ApJ...806..254A
Gagne et al. Paper VII. 2015ApJS..219...33G 2015ApJS..219...33G This catalog
Boucher et al. Paper VIII. 2016ApJ...832...50B 2016ApJ...832...50B
Gagne et al. Paper IX. 2017ApJS..228...18G 2017ApJS..228...18G
Desrochers et al. Paper X. 2018ApJ...852...55D 2018ApJ...852...55D
Gagne et al. Paper XI. 2018ApJ...856...23G 2018ApJ...856...23G Cat. J/ApJ/856/23
Gagne et al. Paper XII. 2018ApJ...860...43G 2018ApJ...860...43G Cat. J/ApJ/860/43
Gagne et al. Paper XIII. 2018ApJ...862..138G 2018ApJ...862..138G
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Sep-2015