Journal Article

<i>XMM–Newton</i> first X-ray detection of the low-ionization broad absorption line quasar PG 1700+518

L. Ballo, E. Piconcelli, C. Vignali and N. Schartel

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 415, issue 3, pages 2600-2606
Published in print August 2011 | ISSN: 0035-8711
Published online August 2011 | e-ISSN: 1365-2966 | DOI:
XMM–Newton first X-ray detection of the low-ionization broad absorption line quasar PG 1700+518

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We report the first high-energy detection of PG 1700+518, a well-known low-ionization broad absorption line quasar (quasi-stellar object, QSO). Due to previous X-ray non-detection, it was classified as soft X-ray weak QSO. We observed PG 1700+518 with XMM–Newton for about 60 ks divided in three exposures. The spectrum below 2 keV is very steep, Γ∼ 2.4–3.8, while at higher energies the extremely flat emission (photon index Γ∼ 0.15, when modelled with a power law) suggests the presence of strong absorption (NH, pl∼ 2 × 1023 cm−2, Γ fixed to 1.8) or a reflection-dominated continuum. The broad-band flux is consistent with previous non-detection. Simultaneous European Photon Imaging Camera (EPIC) and Optical Monitor (OM) data confirm its X-ray weakness (observedαox∼−2.2). The level of obscuration derived from the X-ray spectra of PG 1700+518 cannot explain its soft X-ray nuclear weakness unless a column density of NH≳ 2 × 1024 cm−2 is present.

Keywords: galaxies: active; quasars: individual: PG 1700+518; X-rays: galaxies

Journal Article.  5179 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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