Details

Autor(en) / Beteiligte

• Kriss, Gerard A.
• Lee, Julia C.
• Danehkar, Ashkbiz

Titel

A Search for H i Lyα Counterparts to Ultrafast X-Ray Outflows

Ist Teil von

• The Astrophysical journal, 2018-06, Vol.859 (2), p.94

Ort / Verlag

Philadelphia: IOP Publishing

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Electronic Journals Library - Freely accessible e-journals

Beschreibungen/Notizen

• Abstract Prompted by the H i Ly α absorption associated with the X-ray ultrafast outflow at −17,300 km s −1 in the quasar PG 1211+143, we have searched archival UV spectra at the expected locations of H i Ly α absorption for a large sample of ultrafast outflows identified in XMM-Newton and Suzaku observations. Sixteen of the X-ray outflows have predicted H i Ly α wavelengths falling within the bandpass of spectra from either the Far Ultraviolet Spectroscopic Explorer or the Hubble Space Telescope , although none of the archival observations were simultaneous with the X-ray observations in which ultrafast X-ray outflows (UFOs) were detected. In our spectra broad features with FWHM of 1000 km s −1 have 2 σ upper limits on the H i column density of generally ≲2 × 10 13 cm −2 . Using grids of photoionization models covering a broad range of spectral energy distributions (SEDs), we find that producing Fe xxvi Ly α X-ray absorption with equivalent widths >30 eV and associated H i Ly α absorption with requires total absorbing column densities and ionization parameters log ξ ≳ 3.7. Nevertheless, a wide range of SEDs would predict observable H i Ly α absorption if ionization parameters are only slightly below peak ionization fractions for Fe xxv and Fe xxvi . The lack of Ly α features in the archival UV spectra indicates that the UFOs have very high ionization parameters, that they have very hard UV-ionizing spectra, or that they were not present at the time of the UV spectral observations owing to variability.