J/A+A/638/A131 Radial velocities of 643 DA white dwarfs (Napiwotzki+, 2020)
The ESO supernovae type Ia progenitor survey (SPY).
The radial velocities of 643 DA white dwarfs.
Napiwotzki R., Karl C.A., Lisker T., Catalan S., Drechsel H., Heber U.,
Homeier D., Koester D., Leibundgut B., Marsh T.R., Moehler S., Nelemans G.,
Reimers D., Renzini A., Stroeer A., Yungelson L.
<Astron. Astrophys. 638, A131 (2020)>
=2020A&A...638A.131N 2020A&A...638A.131N (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Stars, white dwarf ; Radial velocities
Keywords: techniques: radial velocities - binaries: close -
binaries: spectroscopic - supernovae: general - white dwarfs
Abstract:
Close double degenerate binaries are one of the favoured progenitor
channels for type Ia supernovae, but it is unclear how many
suitable systems there are in the Galaxy. We report results of a large
radial velocity survey for double degenerate (DD) binaries using the
UVES spectrograph at the ESO VLT (ESO SNIa Progenitor surveY - SPY).
Exposures taken at different epochs are checked for radial velocity
shifts indicating close binary systems.We observed 689 targets
classified as DA (displaying hydrogen-rich atmospheres), of which 46
turned out to possess a cool companion. We measured radial velocities
(RV) of the remaining 643 DA white dwarfs.We managed to secure
observations at two or more epochs for 625 targets, supplemented by
eleven objects meeting our selection criteria from literature. The
data reduction and analysis methods applied to the survey data are
described in detail. The sample contains 39 double degenerate
binaries, only four of which were previously known. 20 are
double-lined systems, in which features from both components are
visible, the other 19 are single-lined binaries. We provide absolute
RVs transformed to the heliocentric system suitable for kinematic
studies. Our sample is large enough to sub-divide by mass: 16 out of
44 low mass targets (≤0.45M☉) are detected as DDs, while just
23 of the remaining 567 with multiple spectra and mass >0.45M☉
are double. Although the detected fraction amongst the low mass
objects (36.4±7.3%) is significantly higher than for the
higher-mass, carbon/oxygen-core dominated part of the sample
(3.9±0.8%), it is lower than the detection efficiency based upon
companion star masses of 0.05M☉ or higher and a 100% binary
fraction. This suggests either companion stars of mass below
0.05M☉ or some of the low mass white dwarfs are single.
Description:
(UVES) of the UT2 telescope (Kueyen) of the ESO VLT. UVES is a high
resolution Echelle spectrograph, which can reach a resolution of
110000 in the red region with a narrow slit.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
objects.dat 79 1391 List of spectra
sp/* . 1391 Individual spectra
tableb1.dat 152 1402 RV measurements for the SPY DA white dwarfs
tablec2.dat 70 643 Gaia DR2 IDs, effective temperatures, gravities
and masses for the SPY DA white dwarfs
telluric.dat 15 96901 Telluric template for water absorption
correction (data for Fig. 3)
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See also:
J/A+A/378/556 : UVES/VLT spectra of white dwarfs (Koester+, 2001)
J/A+A/400/877 : White dwarfs 3D kinematics, SPY project (Pauli+, 2003)
J/A+A/447/173 : White dwarfs 3D-kinematics, SPY project. II. (Pauli+, 2006)
J/MNRAS/467/1414 : Radial velocity changes for 439 white dwarfs (Maoz+, 2017)
Byte-by-byte Description of file: objects.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name star name
14- 15 I2 h RAh Right ascension (J2000)
17- 18 I2 min RAm Right ascension (J2000)
20- 24 F5.2 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 79 A42 --- FileName Name of spectrum file, in subdirectory sp (1)
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Note (1): description of the header part of the spectra:
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Line Bytes Format Units Explanation
----------------------------------------------------------------------------
1 13-54 A42 --- name of intermediate file
2 3-32 A30 --- root name blue file in ESO archive (used for
constructing the file name of the spectrum)
3 5- 9 I5 --- number of spectral points
4 22-34 A13 --- ESO target name
5 17-32 A36 --- ESO observation name
6 18-36 A19 --- observation start in ISO 8601 format
7 12-30 F19.17 --- airmass
8 10-28 F19.16 h right ascension
9 10-29 F20.16 deg declination
10 11-14 I4 year epoch of coordinates
11 8-26 F19.13 s local siderial time at start of observation
12 8-12 I5 s UTC at start of observation
13 14-32 F19.14 year decimal date at start of observation
14 13-18 F18.10 d Julian data at start of observation
15 13-19 F19.15 s exposure time
16 18-36 F18.10 d Julian date mid exposure
17 43-47 F5.3 --- scaling factor for water vapour correction
----------------------------------------------------------------------------
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Object name
14- 23 F10.4 d HJD Heliocentric Julian date at mid-exposure
(HJD-2400000)
25- 30 F6.1 km/s HRV Heliocentric radial velocity (1)
32- 36 F5.1 km/s e_HRV rms uncertainty on HRV
38- 42 F5.1 0.1nm b_lambda ? Lower limit of the wavelength range used to
fit the line profiles (2)
44- 47 F4.1 0.1nm B_lambda ? Upper limit of the wavelength range used to
fit the line profiles (2)
49- 54 F6.1 km/s ? Weighted average of heliocentric radial
velocity measurements
56- 59 F4.1 km/s e_ ? rms uncertainty on (3)
61 A1 --- l_chi2 Limit flag on chi2
62- 69 F8.2 --- chi2 ? chi2 value (4)
71 A1 --- l_logp Limit flag on logp
72- 78 F7.2 [-] logp ? Logarithmic probability that chi2 is as
high or higher for a star with constant radial
velocity (5)
79- 80 A2 --- n_logp [dd DD] Note (6)
82-152 A71 --- Com Comments
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Note (1): If photospheric CaII lines were present, the CaK lines was included in
the measurement.
Observations done under poor conditions (usually repeated afterwards) are
included in this table. Errors are often large due to poor signal to noise
levels, but could carry useful phase information.
Note (2): An empty entry indicates the standard ±15Å interval.
Larger values were used, when a sharp line core was missing (see text).
Sometimes an asymmetric range was chosen to avoid flaws in the spectra.
Note (3): The error is computed including the estimate for instrumental
systematics calculated from the telluric lines and comparison between
Ca and H lines when present.
Note (4): chi2 values computed for the null hypothesis that RV is constant.
Again, our estimates for the systematic errors are included.
10000 indicates chi^2 ≥10000.
Note (5): The smaller the values the higher the confidence that the star is RV
variable.
Note (6): Code as follows:
DD = A binary is assumed for probability logp < -4
dd = Double-lined systems not exceeding our RV variation threshold, but
identified by visual inspection
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Byte-by-byte Description of file: tablec2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Object Name
14- 32 I19 --- GaiaDR2 ? Gaia DR2 ID
34- 39 I6 K Teff Effective temperature
40 A1 --- n_Teff [)] ) for fixed value
42- 45 F4.2 [cm/s2] logg Surface gravity
46 A1 --- n_logg [)] ) for fixed value
48- 52 F5.3 Msun Mass ? Mass
54- 70 A17 --- Rem References/remarks (1)
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Note (1): References/remarks:
ambiguous = Koester et al. (2009, Cat. J/A+A/505/441) reported a cool and a
hot solution. The solution yielding the smallest chi2 is
included
BL02 = Bergeron & Liebert (2002ApJ...566.1091B 2002ApJ...566.1091B)
GBD12, phot = Giammichele et al. (2012ApJS..199...29G 2012ApJS..199...29G), Teff and logg derived
from photometric spectral energy distribution and
trigonometric parallax
GBR11 = Gianninas et al. (2011, Cat. J/ApJ/743/138), fit of Balmer lines
KNV05 = Koester et al. (2005A&A...439..317K 2005A&A...439..317K), helium-rich DABZ
KV12 = Kawka & Vennes (2012, Cat. J/MNRAS/425/1394), fit of Balmer lines
LBSS93 = Liebert et al. (1993ApJ...418..426L 1993ApJ...418..426L), binary of magnetic and
non-magnetic WD
magnetic = magnetic DAs, Zeeman splitting of the line cores. See text for
details on the fit procedure
new = white dwarf not included in the Koester et al. (2009,
Cat. J/A+A/505/441) analysis. Analysed using the same model grid
new/NLTE = hot DAO white dwarfs, analysed using the grid of NLTE model
atmospheres described in Napiwotzki (1999A&A...350..101N 1999A&A...350..101N)
primary = Parameters of the primary from a simultaneous fit of primary
and secondary. See text
WB94 = Wesemael et al. (1994ApJ...429..369W 1994ApJ...429..369W), fit of primary and
secondary parameters using lines and spectral energy
distribution
HNLE97 = Heber et al. (1997A&A...324L..53H 1997A&A...324L..53H): genuineDAB, helium line
profile variations
K09 = Koester et al. (2009, Cat. J/A+A/505/441): visual double
FK97 = Finley & Koester (1997ApJ...489L..79F 1997ApJ...489L..79F): visual double
J98 = Jordan et al. (1998A&A...330..277J 1998A&A...330..277J): visual double
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Byte-by-byte Description of file: telluric.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda Wavelength
10- 15 F6.4 --- Strength Relative absorption strength of telluric
absorption (mostly water vapour) at Paranal
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Acknowledgements:
Ralf Napiwotzki, r.napiwotzki(at)herts.ac.uk
(End) Patricia Vannier [CDS] 30-Apr-2020