J/A+A/458/541 Soft X-ray standards (Beuermann+, 2006)
Establishing HZ43 A, Sirius B, and RXJ1856-37 as soft X-ray standards:
a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer,
and the ROSAT PSPC.
Beuermann K., Burwitz V., Rauch T.
<Astron. Astrophys. 458, 541 (2006)>
=2006A&A...458..541B 2006A&A...458..541B
ADC_Keywords: X-ray sources ; Stars, standard
Keywords: methods: data analysis - stars: white dwarfs - stars: neutron -
stars: fundamental parameters -
Abstract:
We analyze the Chandra LETG+HRC observations of the white dwarfs HZ43A
and Sirius B and of the neutron star RX J185635-3754 with the aim of
resolving current uncertainties in the soft X-ray spectral fluxes and
photospheric parameters of the three stars. We apply the derived
photon spectra to a cross-calibration of the LETG+HRC-S with the
short-wavelength EUVE spectrometer and the ROSAT PSPC.
Description:
Table A1 contains the area correction functions to the Chandra
LETG+HRCS effective areas for the negative and positive dispersion
directions, alphaneg, alphapos, and their area-weighted mean alpha
as well as the corrected effective areas for a gravity of HZ43A of
logg=7.90. Tables A2 and A3 are for logg=7.80 and 8.00, respectively.
The corrected area A is obtained as the recommended area of the
Chandra November 2004 release (http://cxc.harvard.edu/cal/Letg,
LETG/HRC-S Effective Area, updated November 2004), referred to as A0
in the paper, multiplied with the correction function alpha (see
Section 4.4.1 of the paper for further explanation). The variation of
the correction functions alpha and the corrected areas A between the
three tables indicate their systematic errors around the nominal
values of Table A1 which are depicted in Fig. 5 of the paper. The
columns of Tables A1 to A3 provide the wavelength Lambda (Å),
alphaneg, alphapos, alpha, Aneg (cm2), Apos (cm2), and A (cm2).
The header to each Table contains the parameters of the respective
fit.
Table A4 contains the best-fit incident soft X-ray spectra of HZ43A,
SiriusB, and RXJ1856-37 for a gravity of HZ43A of logg=7.90 as shown
in Fig. 6 of the paper (see also Table 3 of the paper). Tables A5 and
A6 are for logg=7.80 and 8.00, respectively.
The best-fit spectra are based on the most recent version of the
Tuebingen Model Atmosphere Package TMAP (Werner et al. 2003, in:
Workshop on Stellar Atmosphere Modeling, eds. I. Hubeny, D. Mihalas,
K. Werner, ASP Conf. Ser. 288, 31; Rauch & Deetjen 2003, ASP Conf.
Ser. 288, 103). The columns of Tables A1 to A3 provide the wavelength
Lambda (Å) and the photon fluxes of the three stars in
photons/cm2/s/Å. The header to each Table contains the parameters
of the respective fit.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------
13 16 21.9 +29 05 55 HZ 43 = HIP 64766
06 45 09.0 -16 43 06 Sirius B = HD 48915B
18 56 35.1 -37 54 33 RXJ1856-37 = RX J185635.1-375433
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 85 240 Area correction functions for logg(HZ43)=7.90
tablea2.dat 85 240 Area correction functions for logg(HZ43)=7.80
tablea3.dat 85 240 Area correction functions for logg(HZ43)=8.00
tablea4.dat 43 384 Best-fit incident soft X-ray spectra for
logg(HZ43)=7.90
tablea5.dat 43 384 Best-fit incident soft X-ray spectra for
logg(HZ43)=7.80
tablea6.dat 43 384 Best-fit incident soft X-ray spectra for
logg(HZ43)=8.00
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Byte-by-byte Description of file (17 headlines): tablea[123].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Select [a-d] Same neg/pos dispersion selection
3- 7 F5.1 0.1nm lambda Wavelength
10- 20 E11.6 --- alphaneg Area correction function for negative
dispersion direction
23- 33 E11.6 --- alphapos Area correction function for positive
dispersion direction
37- 46 E10.6 --- alpha Area correction function for area-weighted
mean of alphaneg and alphapos
49- 59 E11.6 cm+2 Aneg Corrected effective area for negative
dispersion direction
62- 72 E11.6 cm+2 Apos Corrected effective area for positive
dispersion direction
76- 85 E10.6 cm+2 A Corrected effective area for area-weighted
mean of Aneg and Apos
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Byte-by-byte Description of file (17 headlines): tablea[456].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.1 0.1nm lambda Wavelength
10- 19 E10.6 10ph/cm2/s/nm BF1 ? HZ43 A best-fit incident soft X-ray
spectra (in ph/cm2/s/Å)
22- 31 E10.6 10ph/cm2/s/nm BF2 ? Sirius B Best-fit incident soft X-ray
spectra (in ph/cm2/s/Å)
34- 43 E10.6 10ph/cm2/s/nm BF3 ? RXJ1856-37 best-fit incident soft
X-ray spectra (in ph/cm2/s/Å)
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Acknowledgements:
Klaus Beuermann, beuermann(at)uni-sw.gwdg.de
History:
* 13-Oct-2006: Original files
* 08-Feb-2008: Corrected files from author
(End) Patricia Vannier [CDS] 14-Aug-2006