J/AJ/157/231 MLSDSS-GaiaDR2 sample of M and L dwarfs (Kiman+, 2019)
Exploring the age-dependent properties of M and L dwarfs using Gaia and SDSS.
Kiman R., Schmidt S.J., Angus R., Cruz K.L., Faherty J.K., Rice E.
<Astron. J., 157, 231-231 (2019)>
=2019AJ....157..231K 2019AJ....157..231K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, M-type ; Stars, L-type ; Proper motions ;
Radial velocities ; Photometry, SDSS ; Photometry, infrared ;
Extinction ; Equivalent widths ; Stars, distances
Keywords: stars: activity - stars: kinematics and dynamics - stars: low-mass
Abstract:
We present a sample of 74216 M and L dwarfs constructed from two existing
catalogs of cool dwarfs spectroscopically identified in the Sloan Digital
Sky Survey (SDSS). We cross-matched the SDSS catalog with Gaia DR2
(Cat. I/345) to obtain parallaxes and proper motions and modified the
quality cuts suggested by the Gaia Collaboration to make them suitable for
late-M and L dwarfs. We also provide relations between Gaia colors and
absolute magnitudes with spectral type and conclude that (G-GRP) has
the tightest relation to spectral type for M and L dwarfs. In addition,
we study magnetic activity as a function of position on the color-magnitude
diagram, finding that Hα magnetically active stars have, on average,
redder colors and/or brighter magnitudes than inactive stars. This effect
cannot be explained by youth alone and might indicate that active stars
are magnetically inflated, binaries, and/or high metallicity. Moreover,
we find that vertical velocity and vertical action dispersion are
correlated with Hα emission, confirming that these two parameters
are age indicators. We also find that stars below the main sequence have
high tangential velocity, which is consistent with a low metallicity
and old population of stars that belong to the halo or thick disk.
Description:
In this paper, we present the MLSDSS-GaiaDR2 sample of M and L dwarfs
including spectral types, Hα measurements, survey photometry,
and Galactic kinematics. The compilation of the MLSDSS-GaiaDR2 sample
was accomplished in two parts: assembling the base sample, dubbed the
"MLSDSS" sample, and then cross-matching it with the Gaia Data Release 2
(DR2; Gaia Collaboration et al. 2018, Cat. I/345). The MLSDSS sample
is based on data from the SDSS Data Releases 7, 10, and 12 (DR7; DR10;
DR12; Abazajian et al. 2009, Cat. II/294; Ahn et al. 2014ApJS..211....1H 2014ApJS..211....1H;
Alam et al. 2015, Cat. V/147) and the SDSS-III Baryon Oscillation
Spectroscopic Survey (BOSS; Eisenstein et al. 2011AJ....142...72E 2011AJ....142...72E;
Dawson et al. 2013AJ....145...10D 2013AJ....145...10D).
We cross-matched the MLSDSS sample with Gaia DR2 to obtain precise
proper motions and parallaxes. First, we propagated the positions from
the SDSS epoch (ranging from 1999 to 2007) to the Gaia DR2 epoch (2015.5)
using the proper motions in MLSDSS. Second, we queried the Gaia Archive
(http://gea.esac.esa.int/archive/) and selected all the objects within
a radius of 5" of the 2015.5 position. We found that 98% (73003 stars)
of MLSDSS stars have at least one match in Gaia DR2. Of these, 8269 have
between two and five matches within a 5" radius. To find a single best
match, we propagated the position of each match back to the SDSS epoch
using the Gaia DR2 proper motion and kept only the closest match between
the Gaia position at the SDSS epoch and the SDSS position.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 845 74216 MLSDSS-GaiaDR2 (Cat. I/345) sample
--------------------------------------------------------------------------------
See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/123/3409 : SDSS M, L, and T dwarfs (Hawley+, 2002)
J/AJ/131/2722 : New L and T dwarfs from the SDSS (Chiu+, 2006)
J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008)
J/AJ/139/1808 : Colors and kinematics of SDSS L dwarfs (Schmidt+, 2010)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/AJ/149/158 : The BUD sample. I. L dwarf activity sample (Schmidt+, 2015)
J/ApJ/810/158 : M,L,T dwarfs fundamental parameters and SEDs
(Filippazzo+, 2015)
J/AJ/154/112 : NIR spectroscopy of new L and T dwarf candidates
(Kellogg+, 2017)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 d MJDS Modified Julian Date from SDSS (MJD)
7- 10 A4 --- Plate Plate number from SDSS (PLATE)
12- 15 A4 --- Fiber Fiber number from SDSS (FIBER)
17- 36 I20 --- SolID Gaia DR2 solution identifier (solution_id)
38- 65 A28 --- DR2Name Unique Gaia source designation (unique
across all Data Releases)
(Gaia DR2 NNNNNNNNNNNNNNNNNNN)
(designation)
67- 86 I20 --- Source Unique Gaia source identifier (unique
within DR2) (source_id)
88- 91 I4 yr Epoch [2015]? Reference epoch from Gaia DR2
(refepochgaia)
93- 94 I2 --- SpType [0/18] Spectral type (SPT)
96-110 F15.11 deg RAdegG ? Right Ascension (ICRS) at Ep=2015.5 from
Gaia DR2 (RA)
112-118 F7.4 mas e_RAdegG ? Standard error of Right Ascension
(RA_ERR)
120-134 F15.11 deg DEdegG ? Declination (ICRS) at Ep=2015.5 from
Gaia DR2 (DEC)
136-142 F7.4 mas e_DEdegG ? Standard error of Declination (DEC_ERR)
144-151 F8.3 mas/yr pmRAG [-926.08/463.376]? Proper motion in right
ascension direction in Gaia DR2
(pmRA*cosDE) (PMRA)
153-157 F5.3 mas/yr e_pmRAG [0.017/5.041]? Standard error of proper
motion in right ascension direction
(PMRA_ERR)
159-166 F8.3 mas/yr pmDEG [-974.405/295.492]? Proper motion in
declination direction in Gaia DR2 (PMDEC)
168-172 F5.3 mas/yr e_pmDEG [0.03/4.775]? Standard error of proper
motion in declination direction
(PMDEC_ERR)
174-181 F8.3 km/s RV [-992.083/2658.4]? Radial velocity from
MLSDSS (RV)
183-190 F8.3 km/s e_RV [0.27/1507.57]? Radial velocity error
(RV_ERR)
192-201 F10.6 deg RAdeg Right Ascension in SDSS photometric object
(ICRS) (RA_SDSS)
203-212 F10.6 deg DEdeg Declination in SDSS photometric object
(ICRS) (DEC_SDSS)
214-220 F7.3 mag umag [-24.259/27.937]? SDSS u band magnitude
(PSFMAG)
222-228 F7.3 mag gmag [-13.204/30.123]? SDSS g band magnitude
(PSFMAG)
230-238 F9.3 mag rmag [-5.795/31.2]? SDSS r band magnitude
(PSFMAG)
240-248 F9.3 mag imag [-2.063/24.348]? SDSS i band magnitude
(PSFMAG)
250-258 F9.3 mag zmag [0/22.545]? SDSS z band magnitude (PSFMAG)
260-266 F7.3 mag e_umag [0/109.1]? Error on umag (PSFMAG_ERR)
268-274 F7.3 mag e_gmag [0/113.267]? Error on gmag (PSFMAG_ERR)
276-282 F7.3 mag e_rmag [0/539.866]? Error on rmag (PSFMAG_ERR)
284-290 F7.3 mag e_imag [0/12.085]? Error on imag (PSFMAG_ERR)
292-298 F7.3 mag e_zmag [0/6.68]? Error on zmag (PSFMAG_ERR)
300 I1 --- Goodphot [0/1] Good photometry flag for SDSS
riz-bands (1=good photometry)
(GOODPHOT_SDSS)
302-307 F6.3 mag Au [0/23.656] Extinction correction for u band
(EXTINCTION)
309-314 F6.3 mag Ag [0/17.406] Extinction correction for g band
(EXTINCTION)
316-321 F6.3 mag Ar [0/12.624] Extinction correction for r band
(EXTINCTION)
323-328 F6.3 mag Ai [0/9.573] Extinction correction for i band
(EXTINCTION)
330-335 F6.3 mag Az [0/6.787] Extinction correction for z band
(EXTINCTION)
337-343 F7.1 mas/yr pmRAS [-2741.4/6972.3]? Proper motion in right
ascension direction in MLSDSS (PMRA_SDSS)
345-350 F6.1 mas/yr e_pmRAS [0.5/4880.4]? Proper motion error in right
ascension direction (PMRAERRSDSS)
352-358 F7.1 mas/yr pmDES [-5628.3/6359.8]? Proper motion in
declination direction in MLSDSS
(PMDEC_SDSS)
360-365 F6.1 mas/yr e_pmDES [0.4/5361.6]? Proper motion error in
declination direction (PMDECERRSDSS)
367 I1 --- Goodpm [0/1] Good proper motion flag for MLSDSS
(1=good proper motion) (GOODPM_SDSS)
369-375 F7.1 d MJDM [50606.3/51955.8]? Modified Julian Date
from 2MASS (MJD_2MASS)
377-386 F10.6 deg RAdegM ? Right Ascension in 2MASS (J2000)
(RA_2MASS)
388-397 F10.6 deg DEdegM ? Declination in 2MASS (J2000) (DEC_2MASS)
399-404 F6.3 mag Jmag [10.475/17.573]? 2MASS J band magnitude
(MAG_2MASS)
406-411 F6.3 mag Hmag [9.514/17.554]? 2MASS H band magnitude
(MAG_2MASS)
413-418 F6.3 mag Ksmag [9.172/17.475]? 2MASS Ks band magnitude
(MAG_2MASS)
420-424 F5.3 mag e_Jmag [0/0.294]? Error on Jmag (MAGERR2MASS)
426-430 F5.3 mag e_Hmag [0/0.449]? Error on Hmag (MAGERR2MASS)
432-436 F5.3 mag e_Ksmag [0/0.513]? Error on Ksmag (MAGERR2MASS)
438 I1 --- ACTHA [0/1]? Active flag (1=active, 0=inactive)
(ACTHA)
440-449 F10.4 0.1nm EW(HA) [-2833.76/8612.98] Hα equivalent
width (Å) (EWHA)
451-460 E10.5 0.1nm e_EW(HA) [8.9685e-11/52507]? Error on EW(HA) (Å)
(EWHA_ERR)
462-471 F10.4 --- LHa/Lbol [-9972.13/7242.89] Fractional Hα
luminosity (LHALBOL)
473-482 F10.4 --- e_LHa/Lbol [0/12849.6]? Error on LHaLbol (LHALBOL_ERR)
484 I1 --- Goodmatch [0/1] Good matches with Gaia DR2 (1=good,
0=probable mismatch) (GOODMATCH)
486-493 F8.4 mas Plx [-18.1765/107.56]? Parallax in Gaia DR2
(parallax)
495-500 F6.4 mas e_Plx [0.0202/4.3812]? Standard error of parallax
(parallax_error)
502-504 I3 --- Ngood [26/944]? Number of good observations AL
(astrometricngoodobsal)
506-515 E10.5 --- chi2 [21.366/548330]? AL chi-square value
(astrometricchi2al)
517-518 I2 --- Nper [1/22]? Number of visibility periods used
in Astrometric solution
(visibilityperiodsused)
520-536 E17.9 e-/s FG [48.9402/144743]? G band mean flux
(photgmean_flux)
538-554 E17.9 e-/s e_FG [0.54341/399.304]? Error on G band mean
flux (photgmeanfluxerror)
556-572 E17.9 --- RFG [8.92957/6068.98]? G band mean flux divided
by its error
(photgmeanfluxover_error)
574-582 F9.6 mag Gmag [12.7868/21.4643]? G band mean magnitude
(photgmean_mag)
584-600 E17.9 e-/s FBP [3.2284/47515.5]? Integrated GBP mean
flux (photbpmean_flux)
602-618 E17.9 e-/s e_FBP [0.0726138/1553.09]? Error on FBP
(photbpmeanfluxerror)
620-636 E17.9 e-/s RFBP [0.0114300/900.539]? Integrated GBP mean
flux divided by its error
(photbpmeanfluxover_error)
638-646 F9.6 mag BPmag [13.6593/24.0789]? Integrated GBP mean
magnitude (photbpmean_mag)
648-664 E17.9 e-/s FRP [34.1454/149404]? Integrated GRP mean
flux (photrpmean_flux)
666-682 E17.9 e-/s e_FRP [0.465379/2611.25]? Error on FRP
(photrpmeanfluxerror)
684-700 E17.9 e-/s RFRP [1.05891/6746.61]? Integrated GRP mean
flux divided by its error
(photrpmeanfluxover_error)
702-710 F9.6 mag RPmag [11.826/20.9286]? Integrated GRP mean
magnitude (photrpmean_mag)
712-716 F5.3 --- E(BR/RP) [0.824/4.97]? BP/RP excess factor
(photbprpexcessfactor)
718-726 F9.3 pc r-est [9.295/12901.2]? B-J estimated distance
(r_est)
728-736 F9.3 pc b_r-est [9.269/10151.9]? B-J lower bound on the
confidence interval of the estimated
distance (r_lo)
738-746 F9.3 pc B_r-est [9.321/16847.3]? B-J upper bound on the
confidence interval of the estimated
distance (r_hi)
748-755 F8.3 pc r-len [335.299/1699.61]? B-J length scale used
in the prior for the distance estimation
(r_len)
757-764 F8.3 km/s RVmean [-951.28/729.038]? Mean radial component
of the velocity (V_R)
766-773 F8.3 km/s e_RVmean [0/1007.87]? Standard deviation of radial
component of the velocity (VRERR)
775-782 F8.3 km/s VTmean [-387.199/1169.74]? Mean tangential
component of the velocity (V_T)
784-790 F7.3 km/s e_VTmean [0/951.051]? Standard deviation of
tangential component of the velocity
(VTERR)
792-799 F8.3 km/s VZmean [-959.326/2229.28]? Mean vertical component
of the velocity (V_Z)
801-808 F8.3 km/s e_VZmean [0/1175.42]? Standard deviation of vertical
component of the velocity (VZERR)
810-817 F8.3 kpc.km/s JZ [0.005/1980.6]? Median vertical action
(J_Z)
819-826 F8.3 kpc.km/s JZ-16per [0.002/1907.65]? 16th percentile vertical
action (JZ16per)
828-835 F8.3 kpc.km/s JZ-64per [0.006/2005.08]? 64th percentile vertical
action (JZ64per)
837 I1 --- WDM [0/1] White dwarf-M dwarf binary flag
(1=binary, 0=not binary) (WDM)
839 I1 --- astro [0/1] Astrometric subsample
(1=good astrometry, 0=bad astrometry)
(astrometric_sample)
841 I1 --- SubG [0/2]? Sub G subsample
(photometricsamplesubg) (1)
843 I1 --- SubRed [0/2]? Sub Red subsample
(photometricsamplesubred) (1)
845 I1 --- SubMix [0/2]? Sub Mix subsample
(photometricsamplesubmix) (1)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
1 = goodphot;
2 = outlier;
0 = badphot.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 23-Aug-2019