Mehdipour, M;
Kaastra, JS;
Kriss, GA;
Arav, N;
Behar, E;
Bianchi, S;
Branduardi-Raymont, G;
... Walton, DJ; + view all
(2017)
Chasing obscuration in type-I AGN: discovery of an eclipsing clumpy wind at the outer broad-line region of NGC 3783.
Astronomy & Astrophysics
, 607
, Article A28. 10.1051/0004-6361/201731175.
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Abstract
In 2016 we carried out a Swift monitoring programme to track the X-ray hardness variability of eight type-I AGN over a year. The purpose of this monitoring was to find intense obscuration events in AGN, and thereby study them by triggering joint XMM-Newton, NuSTAR, and HST observations. We successfully accomplished this for NGC 3783 in December 2016. We found heavy X-ray absorption produced by an obscuring outflow in this AGN. As a result of this obscuration, interesting absorption features appear in the UV and X-ray spectra, which are not present in the previous epochs. Namely, the obscuration produces broad and blue-shifted UV absorption lines of Lyα, C iv, and N v, together with a new high-ionisation component producing Fe xxv and Fe xxvi absorption lines. In soft X-rays, only narrow emission lines stand out above the diminished continuum as they are not absorbed by the obscurer. Our analysis shows that the obscurer partially covers the central source with a column density of few 1023 cm-2, outflowing with a velocity of few thousand km s-1. The obscuration in NGC 3783 is variable and lasts for about a month. Unlike the commonly seen warm-absorber winds at pc-scale distances from the black hole, the eclipsing wind in NGC 3783 is located at about 10 light days. Our results suggest that the obscuration is produced by an inhomogeneous and clumpy medium, consistent with clouds in the base of a radiatively driven disk wind at the outer broad-line region of the AGN.
| Type: | Article |
|---|---|
| Title: | Chasing obscuration in type-I AGN: discovery of an eclipsing clumpy wind at the outer broad-line region of NGC 3783 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1051/0004-6361/201731175 |
| Publisher version: | http://doi.org/10.1051/0004-6361/201731175 |
| Language: | English |
| Additional information: | © ESO 2017. This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, X-rays: galaxies, galaxies: active, galaxies: Seyfert, galaxies: individual: NGC 3783, techniques: spectroscopic, ACTIVE GALACTIC NUCLEI, SEYFERT-1 GALAXY NGC-3783, QUASAR PDS 456, BLACK-HOLE, SPECTRAL VARIABILITY, IONIZED-GAS, DISK WINDS, XMM-NEWTON, K-LINES, ABSORPTION |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10038409 |
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