We report the results of XMM-Newton observations of the X-ray bright, radio-loud blazar GB B1428+4217 at a redshift of z=4.72. We confirm the presence of soft X-ray spectral flattening at energies <0.7 keV as reported in previous ROSAT and BeppoSAX observations. At hard X-ray energies the spectrum is consistent with a power-law although we find the spectral slope varied between both XMM-Newton observations and is also significantly different from that reported previously. Whilst we cannot rule-out intrinsic cold absorption to explain the spectral depression, we favour a dust-free warm absorber. Cold absorption requires a column density ~1.4-1.6 x 10^22 cm^-2 whilst a warm absorber could have up to ~10^23 cm^-2 and an ionization parameter ~10^2. The spectrum of GB B1428+4217 shows remarkable parallels with that of the z=4.4 blazar PMN J0525-3343, in which the available evidence is also most consistent with a warm absorber model.

XMM-Newton observations of GB B1428+4217: confirmation of intrinsic soft X-ray absorption / Worsley, M. A.; Fabian, A. C.; Celotti, Anna Lisa; Iwasawa, K.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 350:4(2004), pp. L67-L71. [10.1111/j.1365-2966.2004.07887.x]

XMM-Newton observations of GB B1428+4217: confirmation of intrinsic soft X-ray absorption

Celotti, Anna Lisa;
2004-01-01

Abstract

We report the results of XMM-Newton observations of the X-ray bright, radio-loud blazar GB B1428+4217 at a redshift of z=4.72. We confirm the presence of soft X-ray spectral flattening at energies <0.7 keV as reported in previous ROSAT and BeppoSAX observations. At hard X-ray energies the spectrum is consistent with a power-law although we find the spectral slope varied between both XMM-Newton observations and is also significantly different from that reported previously. Whilst we cannot rule-out intrinsic cold absorption to explain the spectral depression, we favour a dust-free warm absorber. Cold absorption requires a column density ~1.4-1.6 x 10^22 cm^-2 whilst a warm absorber could have up to ~10^23 cm^-2 and an ionization parameter ~10^2. The spectrum of GB B1428+4217 shows remarkable parallels with that of the z=4.4 blazar PMN J0525-3343, in which the available evidence is also most consistent with a warm absorber model.
2004
350
4
L67
L71
https://doi.org/10.1111/j.1365-2966.2004.07887.x
https://arxiv.org/abs/astro-ph/0403601
Worsley, M. A.; Fabian, A. C.; Celotti, Anna Lisa; Iwasawa, K.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/14010
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