2011/04/11 by L. Ballo, Ballo, L., E. Piconcelli +5
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE) #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.1104.2003
Accepted for publication in MNRAS; 7 pages, 5 figures, 2 tables
arxiv created 2011/04/11 · openalex publication_date 2011/04/11 · arxiv updated 2011/04/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the first high-energy detection of PG 1700+518, a well-known low-ionization broad absorption line quasar (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 ksec divided in three exposures. The spectrum below 2 keV is very steep, Gamma ~ 2.4-3.8, while at higher energies the extremely flat emission (photon index Gamma ~ 0.15, when modelled with a power law) suggests the presence of strong absorption (NH,pl ~ 2×1023 cm-2, Gamma fixed to 1.8), or a reflection-dominated continuum. The broad-band flux is consistent with previous non-detection. Simultaneous EPIC and OM data confirm its X-ray weakness (alphaox = -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.