J/MNRAS/471/4218 4 low-mass white-dwarf candidates velocities (Kilic+, 2017)
A Gemini snapshot survey for double degenerates.
Kilic M., Brown W.R., Gianninas A., Curd B., Bell K.J., Allende Prieto C.
<Mon. Not. R. Astron. Soc., 471, 4218-4227 (2017)>
=2017MNRAS.471.4218K 2017MNRAS.471.4218K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, white dwarf ;
Radial velocities
Keywords: gravitational waves - binaries: close -
stars: individual: SDSS J083446.91+304959.2 -
stars: individual: J123549.88+154319.3 -
stars: individual: J123728.64+491302.6 -
stars: individual: J234248.86+081137.2 -
supernovae: general - white dwarfs
Abstract:
We present the results from a Gemini snapshot radial-velocity survey
of 44 low-mass white-dwarf candidates selected from the Sloan Digital
Sky Survey (SDSS) spectroscopy. To find sub-hour orbital period binary
systems, our time-series spectroscopy had cadences of 2-8min over a
period of 20-30min. Through follow-up observations at Gemini and the
MMT, we identify four double-degenerate binary systems with periods
ranging from 53min to 7h. The shortest period system, SDSS
J123549.88+154319.3, was recently identified as a sub-hour period
detached binary by Breedt and collaborators. Here, we refine the
orbital and physical parameters of this system. High-speed and
time-domain survey photometry observations do not reveal eclipses or
other photometric effects in any of our targets. We compare the period
distribution of these four systems with the orbital period
distribution of known double white dwarfs; the median period decreases
from 0.64 to 0.24d for M=0.3-0.5M☉ to M<0.3M☉
white dwarfs. However, we do not find a statistically significant
correlation between the orbital period and white-dwarf mass.
Description:
We obtained follow-up optical spectroscopy of 34 (10) targets using
the 8-m Gemini North (South) telescope equipped with the Gemini
Multi-Object Spectrograph (GMOS) as part of the programmes
GN-2016A-Q-54, GN-2016B-Q-45, GS-2015A-Q-10, GS-2016A-Q-58 and
GS-2016B-Q-48.
Based on the initial velocity measurements from GMOS, we obtained
additional follow-up data for six targets (J1113+2712, J1237+4913,
J1323+3254, J1407+1241, J1633+3030 and J1716+2838) using the same
set-up as on Gemini North as part of the Fast Turnaround programme
GN-2016A-FT-34.
We used the 6.5-m MMT with the Blue Channel spectrograph to obtain
follow-up data on five targets (J0834+3049, J1032+2147, J1235+1543,
J1237+4913 and J2342+0811) between 2016 January and 2017 March.
We also used the Kitt Peak National Observatory 4-m telescope + KOSMOS
in 2016 December and the Apache Point Observatory 3.5-m telescope with
the Dual Imaging Spectrograph (DIS) in 2017 March to obtain additional
follow-up spectroscopy of J1237+4913.
We obtained follow-up time-series photometry of one of our targets,
J1235+1543, using the McDonald Observatory 2.1-m Otto Struve telescope
with the ProEM camera and the BG40 filter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 98 44 Physical parameters and the summary of radial
velocity measurements for our targets.
table2.dat 114 4 Orbital parameters
tablea1.dat 22 18 J0834+3049 radial velocities
tablea2.dat 22 39 J1235+1543 radial velocities
tablea3.dat 22 41 J1237+4913 radial velocities
tablea4.dat 22 25 J2342+0811 radial velocities
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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 --- SDSS Object SDSS name (JHHMMSS.ss+DDMMSS,s)
21- 25 F5.2 mag g0mag Deredenned g magnitude
27- 31 I5 K Teff Effective temperature
33- 35 I3 K e_Teff Effective temperature error
37- 40 F4.2 [cm/s2] logg Surface gravity
42- 45 F4.2 [cm/s2] e_logg Surface gravity error
47- 50 F4.2 Msun M ? Mass
52- 55 F4.2 Msun e_M ? Mass error
57- 58 I2 --- N Number of spectra
60- 65 F6.1 km/s RVMean Mean radial velocity
67- 70 F4.1 km/s e_RVMean Mean radial velocity error
72- 77 F6.2 --- chi2 chi2 value
79- 85 F7.2 [-] log(p) Probability, p, of obtaining the observed
value of chi2 or higher from random
fluctuations of a constant velocity (1)
87- 98 A12 --- Inst Instrument (Gemini North or Gemini South)
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Note (1): objects with log(p)←4 are identified as binary systems.
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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- 10 A10 --- SName SDSS short name (JHHMM+DDMM)
12- 18 F7.5 d Per Period
20- 26 F7.5 d e_Per Period error
27- 31 F5.1 km/s K Velocity semi-amplitude K
33- 36 F4.1 km/s e_K Velocity semi-amplitude K error
38- 42 F5.1 km/s gamma gamma velocity
44- 47 F4.1 km/s e_gamma gamma velocity error
49- 52 F4.2 --- chi2red Reduced chi2
54- 59 F6.4 Msun f Mass function
61- 64 F4.2 Msun M1 Mass of the primary
66- 67 A2 --- l_M2 [≥ ] Limit flag on M2
68- 71 F4.2 Msun M2 Mass of the secondary
73- 74 A2 --- l_taumerge [≤ ] Limit flag on taumerge
75- 78 F4.1 --- taumerge Merger times due to gravitational wave
radiation
80- 82 A3 --- x_taumerge Units of taumerge
84- 94 A11 --- Table Name of the table with radial velocities
96-114 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
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Byte-by-byte Description of file: tablea?.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 d HJD Heliocentric Julian date (HJD-2457000)
12- 17 F6.1 km/s HV Helioentric velocity error
19- 22 F4.1 km/s e_HV Helioentric velocity error
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Jun-2020