J/A+A/506/1341 Magnetic fields in white dwarfs (Kuelebi+, 2009)
Analysis of hydrogen-rich magnetic white dwarfs detected in the
Sloan Digital Sky Survey.
Kuelebi B., Jordan S., Euchner F., Gaensicke B.T., Hirsch H.
<Astron. Astrophys., 506, 1341-1350 (2009)>
=2009A&A...506.1341K 2009A&A...506.1341K
ADC_Keywords: Stars, white dwarf ; Models ; Magnetic fields
Keywords: stars: white dwarfs - stars: magnetic fields - stars: atmospheres
Abstract:
A large number of magnetic white dwarfs discovered in the SDSS have so
far only been analyzed by visual comparison of the observations with
relatively simple models of the radiation transport in a magnetised
stellar atmosphere.
We model the structure of the surface magnetic fields of the
hydrogen-rich white dwarfs in the SDSS.
Description:
We calculated a grid of state-of-the-art theoretical optical spectra
of hydrogen-rich magnetic white dwarfs (WDs) with magnetic field
strengths of between 1MG and 1200MG for different angles between the
magnetic field vector and the line of sight, and for effective
temperatures between 7000K and 50000K. We used a least squares
minimization scheme with an evolutionary algorithm to find the
best-fit magnetic field geometry of the observed data. We used
centered dipoles or dipoles that had been shifted along the dipole
axis to model the coadded SDSS fiber spectrum of each object.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 133 137 Model fits with centered dipole and offset dipole
models with comparison to literature values
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See also:
J/A+A/420/507 : Isolated massive white dwarfs catalog (Nalezyty+, 2004)
J/AJ/130/734 : SDSS DR2 & DR3 magnetic white dwarfs (Vanlandingham+, 2005)
J/AJ/134/741 : New close binary systems from the SDSS DR5 (Silvestri+, 2007)
J/ApJ/667/1119 : Photoionization cross sections of hydrogen (Zhao+, 2007)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file:table3.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- MWD SDSS name of the object, JHHMMSS.ss+DDMMSS.s
21- 24 I4 --- Plate Plate number of SDSS observation
25 A1 --- --- [-]
26- 30 I5 --- MJD Modified Julian Date of SDSS observation
31 A1 --- --- [-]
32- 34 I3 --- Fiber Fiber number of SDSS observation
36- 41 F6.2 hT Bp Dipole magnetic field strength of the
centered dipole (in 106Gauss)
44- 49 F6.2 hT e_Bp ? rms uncertainty on Bp
51 I1 --- n_Bp [1/2]? very large (1) or very small (2) errors
53- 57 F5.2 deg i Inclination with respect to the line of sight
of the centered dipole
59- 64 F6.2 deg e_i rms uncertainty on i
66 I1 --- n_i [1/2]? very large (1) or very small (2) errors
68- 74 F7.3 hT Boff ? Dipole magnetic field strength of the
offset dipole (in 106Gauss)
75- 81 F7.3 hT e_Boff ? rms uncertainty on Boff
83 I1 --- n_Boff [1/2]? very large (1) or very small (2) errors
85- 89 F5.2 --- zoff/R ? Offset along the axis of the magnetic field
in terms of the stellar radius
92- 97 F6.3 --- e_zoff/R ? rms uncertainty on zoff/rWD
98 A1 --- n_zoff/R [i] i for 1e+99
100-105 F6.3 deg ioff ? Inclination with respect to the line of
sight of the offset dipole
107-112 F6.2 deg e_ioff ? rms uncertainty on ioff
114 I1 --- n_ioff [1/2]? very large (1) or very small (2) errors
116-133 A18 --- fits Comments indicate the model parameters,
field strength and inclination (1)
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Note (1): From the literature, i.e. Gaensicke et al. (2002A&A...394..957G 2002A&A...394..957G),
Schmidt et al. (2003ApJ...595.1101S 2003ApJ...595.1101S), Vanlandingham et al. (2005, Cat.
J/AJ/130/734). Asterisks indicate field strengths or inclinations with
uncertainties greater than 10% in Vanlandingham et al.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Jan-2010