J/MNRAS/425/1394 High proper-motion white dwarfs (Kawka+, 2012)
A study of high proper-motion white dwarfs.
I. Spectropolarimetry of a cool hydrogen-rich sample.
Kawka A., Vennes S.
<Mon. Not. R. Astron. Soc., 425, 1394-1412 (2012)>
=2012MNRAS.425.1394K 2012MNRAS.425.1394K
ADC_Keywords: Stars, white dwarf ; Proper motions ; Photometry
Keywords: stars: fundamental parameters - stars: magnetic field - white dwarfs
Abstract:
We conducted a spectropolarimetric survey of 58 high proper-motion
white dwarfs which achieved uncertainties of ≳2kG in the Hα
line and ≳5kG in the upper Balmer line series. The survey aimed at
detecting low magnetic fields (≲100kG) and helped identify the new
magnetic white dwarfs NLTT2219, with a longitudinal field Bl=-97kG,
and NLTT10480 (Bl=-212kG). Furthermore, we report the possible
identification of a very low-field white dwarf with Bl=-4.6kG. The
observations show that ≈5 per cent of white dwarfs harbour low fields
(∼10 to ∼102kG) and that increased survey sensitivity may help
uncover several new magnetic white dwarfs with fields below ∼1kG. A
series of observations of the high-field white dwarf NLTT12758
revealed changes in polarity occurring within an hour possibly
associated with an inclined, fast rotating dipole. Also, the relative
strength of the π and σ components in NLTT12758 possibly
revealed the effect of a field concentration ('spot'), or, most
likely, the presence of a non-magnetic white dwarf companion. Similar
observations of NLTT13015 also showed possible polarity variations,
but without a clear indication of the time-scale. The survey data also
proved useful in constraining the chemical composition, age and
kinematics of a sample of cool white dwarfs as well as in constraining
the incidence of double degenerates.
Description:
We obtained two sets of observations using the FORS spectrograph
attached to the 8-m telescopes at Paranal Observatory. The first data
set was obtained with the FORS1 attached to UT2. The second set of
observations was obtained with the FORS2 attached to UT1. Additional
spectra of the programme stars were obtained at ESO using the New
Technology Telescope (NTT) and at Cerro Tololo Inter-American
Observatory (CTIO) and Kitt Peak National Observatory (KPNO). We also
collected spectra from the Sloan Digital Sky Survey (SDSS) Data
Release 8, and recycled our published spectra (Kawka & Vennes,
2006ApJ...643..402K 2006ApJ...643..402K, Cat. J/ApJ/643/402).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 161 58 VLT FORS observations
table2.dat 80 59 Atmospheric and other properties
table4.dat 52 55 Magnetic field measurements - non-detections
tablea1.dat 73 60 Optical and infrared magnitudes
tablea2.dat 95 18 SDSS photometry
tableb1.dat 34 155 Individual radial velocity measurements
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See also:
J/ApJS/133/413 : BVRIJHK photometry of cool white dwarfs (Bergeron+, 2001)
J/AJ/128/1825 : Photometry identification of cool white dwarfs (Kilic+, 2004)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/ApJ/643/402 : Cool white dwarfs in the solar neighborhood (Kawka+, 2006)
J/ApJS/190/77 : Detailed analysis of cool WDs in the SDSS (Kilic+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Name
15- 17 A3 --- m_Name Multiplicity index on Name
19- 50 A32 --- ONames Alternate names
52- 53 I2 h RAh Right ascension (J2000)
55- 56 I2 min RAm Right ascension (J2000)
58- 62 F5.2 s RAs Right ascension (J2000)
64 A1 --- DE- Declination sign (J2000)
65- 66 I2 deg DEd Declination (J2000)
68- 69 I2 arcmin DEm Declination (J2000)
71- 75 F5.2 arcsec DEs Declination (J2000)
77- 81 F5.2 mag Pmag [15/18] Photographic magnitude (1)
83- 87 F5.3 arcsec/yr pm [0.16/1.2] Total proper motion
89- 99 A11 "date" Date1 UT date
101 I1 --- N1 Number of complete spectropolarimetric
sequences for Date1
102 A1 --- --- [,]
104-114 A11 "date" Date2 UT date
116 I1 --- N2 ? Number of complete spectropolarimetric
sequences for Date2
117 A1 --- --- [,]
119-129 A11 "date" Date3 UT date
131 I1 --- N3 ? Number of complete spectropolarimetric
sequences for Date3
132 A1 --- --- [,]
134-144 A11 "date" Date4 UT date
146 I1 --- N4 ? Number of complete spectropolarimetric
sequences for Date4
147 A1 --- --- [,]
149-159 A11 "date" Date5 UT date
161 I1 --- N5 ? Number of complete spectropolarimetric
sequences for Date5
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Note (1): Photographic magnitudes from Salim & Gould (2003ApJ...582.1011S 2003ApJ...582.1011S,
Cat. J/ApJ/582/1011), except PM J11480-4523 from Lepine (2005AJ....130.1247L 2005AJ....130.1247L,
Cat. J/AJ/130/1247).
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- WD WD designation (HHMM-DDd)
9 A1 --- m_WD [AB] Multiplicity index on WD
10 A1 --- n_WD Individual note on star (1)
12- 24 A13 --- Name ?=- NLTT identification number (NLTT NNNNN)
25 A1 --- m_Name [AB] Multiplicity index on Name
27- 31 I5 K Teff [5300/14350] Effective temperature
33- 35 I3 K e_Teff rms uncertainty on Teff
38- 41 F4.2 [cm/s2] logg [6.3/8.6] Surface gravity
43- 46 F4.2 [cm/s2] e_logg rms uncertainty on logg
47 A1 --- n_logg [)] Uncertainty flag on logg
49- 52 F4.2 Msun Mass [0.1/1] Star mass
54- 57 F4.2 Msun e_Mass rms uncertainty on Mass
59- 62 F4.2 Gyr Age Star age
64- 68 F5.2 mag VMAG [10/16] Absolute V magnitude
70- 73 F4.2 mag e_VMAG rms uncertainty on VMAG
75- 77 I3 pc Dist [17/204] Distance
79- 80 I2 pc e_Dist rms uncertainty in Dist
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Note (1): Notes as follows:
a = Based on the analysis of Balmer line profiles except for the high-field
DAP white dwarfs NLTT 12758 and NLTT 13015 (see text)
b = Possible DAP white dwarf
c = DAZ white dwarf
d = DAP white dwarf
e = In a common proper-motion binary with a main-sequence star
f = Magnetic DAZ (DAZP) white dwarf (Kawka & Vennes, 2011A&A...532A...7K 2011A&A...532A...7K)
g = DA+DC binary: (DC) Teff=6150±150K, logg=8.11±0.12,
M=0.63±0.08M☉
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Star name
14 A1 --- m_Name Multiplicity index on Name
16- 21 F6.1 dT Bl [-333/21] Longitudinal magnetic field (kGauss)
23- 27 F5.1 dT e_Bl rms uncertainty on Bl (kGauss)
29- 52 A24 --- Lines Lines
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Star name
14- 16 A3 --- m_Name Multiplicity index on Name
18- 23 F6.3 mag Vmag1 ?=- EFOSC V magnitude
25- 30 F6.3 mag Rmag1 ?=- EFOSC R magnitude
32- 37 F6.3 mag Vmag2 ?=- FORS V magnitude
39- 44 F6.3 mag Rmag2 ?=- FORS R magnitude
45- 49 F5.2 mag Vmag ?=- Published V magnitude
51- 54 F4.2 mag e_Vmag ? rms uncertainty on Vmag
57- 58 I2 --- r_Vmag ? magnitude reference (1)
60- 65 F6.3 mag Jmag ?=- 2MASS J magnitude
67- 71 F5.3 mag e_Jmag ? rms uncertainty on Jmag
73 A1 --- n_Jmag [b] b: Kilic et al. (2010ApJS..190...77K 2010ApJS..190...77K,
J/ApJS/190/77) measured J=16.20±0.04
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Note (1): References as follows:
1 = Eggen & Greenstein (1965ApJ...141...83E 1965ApJ...141...83E)
2 = Smith (1997, PhD thesis, Florida Institute of Technology)
3 = Bergeron et al. (2005ApJ...625..838B 2005ApJ...625..838B)
4 = Kawka & Vennes (2012A&A...538A..13K 2012A&A...538A..13K)
5 = Kawka & Vennes (2011A&A...532A...7K 2011A&A...532A...7K)
6 = Eggen (1968ApJ...153..195E 1968ApJ...153..195E)
7 = Salim & Gould (2003ApJ...582.1011S 2003ApJ...582.1011S, J/ApJ/582/1011)
8 = Subasavage et al. (2008AJ....136..899S 2008AJ....136..899S)
9 = Kilkenny et al. (1997MNRAS.287..867K 1997MNRAS.287..867K, Cat. J/MNRAS/287/867)
10 = Subasavage et al. (2007AJ....134..252S 2007AJ....134..252S, Cat. J/AJ/134/252)
11 = Costa et al. (2006AJ....132.1234C 2006AJ....132.1234C)
12 = Greenstein (1984ApJ...276..602G 1984ApJ...276..602G)
13 = Lepine et al. (2009AJ....137.4109L 2009AJ....137.4109L)
14 = Lepine (2005AJ....130.1247L 2005AJ....130.1247L, Cat. J/AJ/130/1247)
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name NLTT identification number (NLTT NNNNN)
12- 30 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
32- 37 F6.3 mag umag SDSS u magnitude
39- 43 F5.3 mag e_umag rms uncertainty on umag
45- 50 F6.3 mag gmag SDSS g magnitude
52- 56 F5.3 mag e_gmag rms uncertainty on gmag
58- 63 F6.3 mag rmag SDSS r magnitude
65- 69 F5.3 mag e_rmag rms uncertainty on rmag
71- 76 F6.3 mag imag SDSS i magnitude
78- 82 F5.3 mag e_imag rms uncertainty on imag
84- 89 F6.3 mag zmag SDSS z magnitude
91- 95 F5.3 mag e_zmag rms uncertainty on zmag
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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- 10 A10 --- Name NLTT identification number (NLTT NNNNN)
11 A1 --- m_Name [AB] Multiplicty index on NLTT
13- 22 F10.5 d BJD Barycentric Julian date (BJD-2450000)
24- 29 F6.1 km/s RV Radial velocity
31- 34 F4.1 km/s e_RV rms uncertainty on RV
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-May-2014