Jul, 2009
Broad-band properties of the hard X-ray cataclysmic variables IGR J00234+6141 and 1RXS J213344.1+510725
ASTRONOMY & ASTROPHYSICS
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- Volume
- 501
- Number
- 3
- First page
- 1047
- Last page
- 1058
- Language
- English
- Publishing type
- DOI
- 10.1051/0004-6361/200911816
- Publisher
- EDP SCIENCES S A
Context. A significant number of cataclysmic variables have been detected as hard X-ray sources in the INTEGRAL survey, most of them of the magnetic intermediate polar type.
Aims. We present a detailed X-ray broad-band study of two new sources, IGR J00234+6141 and 1RXS J213344.1+510725, that allow us to classify them as secure members of the intermediate polar class.
Methods. Timing and spectral analysis of IGR J00234+6141 are based on an XMM-Newton observation and INTEGRAL publicly available data. For 1RXS J213344.1+510725, we use XMM-Newton and Suzaku observations at different epochs, as well as INTEGRAL publicly available data.
Results. We determine a spin period of 561.64 +/- 0.56 s for the white dwarf in IGR J00234+6141. The X-ray pulses are observed up to similar to 2 keV. From XMM-Newton and Suzaku observations of 1RXS J213344.1+510725, we find a rotational period of 570.862 +/- 0.034 s. The observations span three epochs where the pulsation is observed to change at different energies both in amplitude and shape. In both objects, the spectral analysis spanned over a wide energy range, from 0.3 to 100 keV, shows the presence of multiple emission components absorbed by dense material. The X-ray spectrum of IGR J00234+6141 is consistent with a multi-temperature plasma with a maximum temperature of similar to 50 keV. In 1RXS J213344.1+510725, multiple optically thin components are inferred, as well as an optically thick (blackbody) soft X-ray emission with a temperature of similar to 100 eV. This adds 1RXS J213344.1+510725 to the growing group of soft X-ray intermediate polars.
Conclusions. Though showing similar rotational periods and being hard X-ray sources, these two intermediate polars appear different in several respects, among which the presence of a soft X-ray component in 1RXS J213344.1+510725. This source also emits circularly polarized light in the optical band, thus joining the group of soft and polarized intermediate polars as a fifth member. How the hard X-ray and polarized emission are thermalized in these systems is a timely question.
Aims. We present a detailed X-ray broad-band study of two new sources, IGR J00234+6141 and 1RXS J213344.1+510725, that allow us to classify them as secure members of the intermediate polar class.
Methods. Timing and spectral analysis of IGR J00234+6141 are based on an XMM-Newton observation and INTEGRAL publicly available data. For 1RXS J213344.1+510725, we use XMM-Newton and Suzaku observations at different epochs, as well as INTEGRAL publicly available data.
Results. We determine a spin period of 561.64 +/- 0.56 s for the white dwarf in IGR J00234+6141. The X-ray pulses are observed up to similar to 2 keV. From XMM-Newton and Suzaku observations of 1RXS J213344.1+510725, we find a rotational period of 570.862 +/- 0.034 s. The observations span three epochs where the pulsation is observed to change at different energies both in amplitude and shape. In both objects, the spectral analysis spanned over a wide energy range, from 0.3 to 100 keV, shows the presence of multiple emission components absorbed by dense material. The X-ray spectrum of IGR J00234+6141 is consistent with a multi-temperature plasma with a maximum temperature of similar to 50 keV. In 1RXS J213344.1+510725, multiple optically thin components are inferred, as well as an optically thick (blackbody) soft X-ray emission with a temperature of similar to 100 eV. This adds 1RXS J213344.1+510725 to the growing group of soft X-ray intermediate polars.
Conclusions. Though showing similar rotational periods and being hard X-ray sources, these two intermediate polars appear different in several respects, among which the presence of a soft X-ray component in 1RXS J213344.1+510725. This source also emits circularly polarized light in the optical band, thus joining the group of soft and polarized intermediate polars as a fifth member. How the hard X-ray and polarized emission are thermalized in these systems is a timely question.
- Link information
- ID information
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- DOI : 10.1051/0004-6361/200911816
- ISSN : 1432-0746
- Web of Science ID : WOS:000268292200019