J/A+A/570/A107 WDMS from LAMOST DR1 (Ren+, 2014)
White dwarf-main sequence binaries from LAMOST: the DR1 catalogue.
Ren J. J., Rebassa-Mansergas A., Luo A. L., Zhao Y. H., Xiang M. S.,
Liu X. W., Zhao G., Jin G., Zhang Y.
<Astron. Astrophys. 570, A107 (2014)>
=2014A&A...570A.107R 2014A&A...570A.107R
ADC_Keywords: Stars, white dwarf ; Stars, M-type ; Binaries, spectroscopic
Keywords: binaries: spectroscopic - stars: low-mass - white dwarfs -
method: data analysis
Abstract:
White dwarf-main sequence (WDMS) binaries are used to study several
different important open problems in modern astrophysics.
The Sloan Digital Sky Survey (SDSS) identified the largest catalogue
of WDMS binaries currently known. However, this sample is seriously
affected by selection effects and the population of systems containing
cool white dwarfs and early-type companions is under-represented. Here
we search for WDMS binaries within the spectroscopic data release 1 of
the LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope)
survey. LAMOST and SDSS follow different target selection algorithms.
Hence, LAMOST WDMS binaries may be drawn from a different parent
population and thus help in overcoming the selection effects
incorporated by SDSS on the current observed population.
We develop a fast and efficient routine based on the wavelet transform
to identify LAMOST WDMS binaries containing a DA white dwarf and a M
dwarf companion, and apply a decomposition/fitting routine to their
LAMOST spectra to estimate their distances and measure their stellar
parameters, namely the white dwarf effective temperatures, surface
gravities and masses, and the secondary star spectral types.
We identify 121 LAMOST WDMS binaries, 80 of which are new discoveries,
and estimate the sample to be about 90 per cent complete. The LAMOST
and SDSS WDMS binaries are found to be statistically different.
However, this result is not due to the different target selection
criteria of both surveys, but likely a simple consequence of the
different observing conditions. Thus, the LAMOST population is found
at considerably shorter distances (50-450pc) and is dominated by
systems containing early-type companions and hot white dwarfs.
Even though WDMS binaries containing cool white dwarfs are also missed
by the LAMOST survey, the LAMOST WDMS binary sample dominated by
systems containing early-type companions is an important addition to
the current known spectroscopic catalogue. Future LAMOST observations
however are required to increase the small number of LAMOST WDMS
binaries.
Description:
The ascii data of all LAMOST DR1 DA/M binary spectra are presented.
The complete table of stellar parameters, magnitudes, radial
velocities of the LAMOST DA/M binaries are also provided.
The stellar parameters table includes the white dwarf stellar
parameters (effective temperature, surface gravity and mass), spectral
type of the companions and distance when available, however only those
with a S/N higher 12 (second column) are considered in the analysis of
the paper. Spectral types of -1 imply that no values are available.
For completeness, the table also include 181 systems that are not
considered by us as DA/M binaries but that show blue and red
components in their spectra. These are flagged as 1 in the last
column.
The magnitudes table includes the SDSS or Xuyi magnitudes (when
available) and coordinates.
The radial velocities includes the NaI 8183.27,8194.81 absorption
doublet and Halpha emission radial velocities and errors, as well as
the Heliocentric Julian dates and the telescope used for obtaining the
spectra (either LAMOST or SDSS).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 153 318 Catalogue of the 133 DA/M binary spectra, completed
with 185 stars not considered as DA/M binaries
table2.dat 91 121 Magnitudes
table3.dat 72 189 Radial velocities for 69 sources
sp/* . 133 LAMOST DA/M binary spectra
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- JName SDSS designation (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.2 --- S/N ?=0 Signal-to-noise ratio
27- 31 I5 d MJD Modified Julian date of observation
33- 53 A21 --- Plate Plate identifier
55- 56 I2 --- SPID [1/16] Spectrograph identifier
58- 60 I3 --- Fiber [1/248] Fiber identifier
62- 66 I5 K Teff ?=0 White dwarf effective temperature
68- 72 I5 K e_Teff ?=0 White dwarf effective temperature error
74- 77 F4.2 [cm/s2] logg ?=0 White dwarf surface gravity
79- 83 F5.3 [cm/s2] e_logg ?=0 White dwarf surface gravity error
85- 88 F4.2 Msun M ?=0 White dwarf mass
90- 94 F5.3 Msun e_M ?=0 White dwarf mass error
96- 99 I4 pc d ?=0 White dwarf distance
101-103 I3 pc e_d ?=0 White dwarf distance error
105-106 I2 --- Sp [0/6]?=-1 M-subtype of the companion
108 I1 --- f_Sp [0/1] 1=not a genuine DA/M type? (1)
110-153 A44 --- FileName Name of spectrum file in subdirectory sp
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Note (1): the 181 spectra which are flagged "1" are not considered by us as
DA/M binaries but that show blue and red components in their spectra.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- JName SDSS designation (JHHMMSS.ss+DDMMSS.s)
21- 30 F10.6 deg RAdeg Right Ascension J2000 (degrees)
32- 41 F10.6 deg DEdeg Declination J2000 (degrees)
43- 50 F8.5 mag umag ?=0 u-band magnitude
52- 59 F8.5 mag gmag ?=0 g-band magnitude
61- 68 F8.5 mag rmag ?=0 r-band magnitude
70- 77 F8.5 mag imag ?=0 i-band magnitude
79- 86 F8.5 mag zmag ?=0 z-band magnitude
88- 91 A4 --- Flag ?=0 Magnitude origin (SDSS or Xuyi)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- JName SDSS designation (JHHMMSS.ss+DDMMSS.s)
21- 33 F13.5 --- HJD Heliocentric Julian date of observation
35- 41 F7.2 km/s RV(Ha) ?=- Hα emission radial velocity
43- 49 F7.2 km/s e_RV(Ha) ?=- Hα emission radial velocity error
51- 57 F7.2 km/s RV(NaI) ?=- NaI absorption doublet radial velocity
(λ8183.27,8194.81Å)
59- 65 F7.2 km/s e_RV(NaI) ?=- NaI absorption doublet radial velocity error
67- 72 A6 --- Tel Telescope (LAMOST or SDSS)
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 13 F13.8 0.1nm lambda [3599/9100] Wavelength λ
15- 32 F18.10 10-19W/m2/nm Flux Flux (in 10-17erg/cm2/s/Å)
34- 53 F20.15 --- 1/sigma2 Inverse variance for the flux
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Acknowledgements:
Juanjuan Ren, jjren(at)nao.cas.cn
(End) Juanjuan Ren [NAOC, China], Patricia Vannier [CDS] 06-Aug-2014