Effective area calibration of the reflection grating spectrometers of XMM-Newton - II. X-ray spectroscopy of DA white dwarfs

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Volume 497 / No 1 (April I 2009)

A&A, 497 1 (2009) 311-323

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Table 5:

Best-fit parameters of Sirius B and HZ 43A.
Parameter	Search range	Best value^a	Median value^b	Allowed range^c	Best value^a	Median value^b	Allowed range^c
		Short cut-off Lyman pseudocontinuum			Long cut-off Lyman pseudocontinuum
		(model 1)			(model 2)
HZ 43A:
$T_{{\rm eff}}$ (K)	47 000-57 000	51 660	51 660	51 420-51 880	51 530	51 460	51 240-51 690
$\log g$ (m s^-2)	5.8-6.3	6.064	6.065	6.031-6.102	5.893	5.913	5.872-5.941
H-layer mass (10^-11 $M_{\odot }$ )	0.02 $-\infty$	5	0.4	0.3 $-\infty$	11	10	0.25 $-\infty$
ISM H I (10²² m^-2)	0.73-0.97	0.85	0.85	0.81-0.90	0.85	0.84	0.79-0.91
ISM He I (10²² m^-2)	0.053-0.061	0.057	0.058	0.055-0.059	0.057	0.055	0.055-0.058
ISM He II (10²² m^-2)	0.015-0.063	0.038	0.042	0.029-0.047	0.038	0.042	0.029-0.048
f_d=R²/d² (10^-23)		3.037	3.037	3.025-3.050	3.038	3.041	3.031-3.053
Grav. redshift (km s^-1)	10-50	45	45	41-50	30.0	31.5	28.6-33.6
Sirius B:
$T_{{\rm eff}}$ (K)	24 000-26 000	25 360	25 360	25 320-25 410	24 970	24 980	24 940-25 010
$\log g$ (log m s^-2)	6.52-6.72	6.628	6.626	6.624-6.631	6.624	6.623	6.621-6.627
He/H ratio ( $\times 10^{-6}$ )	0-6	0	0.2	0-0.5	0	0.6	0-1.0
ISM H I (10²² m^-2)	0.36-0.80	0.58	0.57	0.50-0.66	0.59	0.59	0.50-0.69
ISM H I/He I	10.0-15.6	12.8	13.0	11.8-14.0	12.8	12.4	11.9-13.9
ISM He II/He	0.19-0.35	0.27	0.27	0.24-0.30	0.27	0.25	0.24-0.30
f_d=R²/d² (10^-21)		4.91	4.93	4.87-4.95	4.95	4.97	4.92-4.99

^a Best values (minimum $\chi^2$ ). ^b Corresponding to the parameters of the spectrum closest to the median of all allowed spectra. ^c Corresponding to $\Delta \chi ^2=2$ (see text for discussion).

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