X-RAY WARM ABSORPTION AND EMISSION IN THE POLAR-SCATTERED SEYFERT 1 GALAXY Mrk 704

Abstract

We present a detailed study of the ionized environment of the Seyfert 1 galaxy Mrk 704 using medium-and high-resolution X-ray spectra obtained with a long XMM-Newton observation. The 0.3-10 keV continuum, well described by a power law (Γ ≈ 1.86) and two blackbodies (kT ≈ 0.085 and 0.22 keV), is found to be affected by a neutral partial covering absorption (N H ≈ 10 23 cm −2 , covering fraction ≈0.22) and two warm absorber components. We identify a low-ionization, ξ ∼ 20 erg cm s −1 , and high outflow velocity, v ∼ 1350 km s −1 , phase producing the O vi and Fe M-shell unresolved-transition array. An additional high-ionization warm absorbing phase with ξ ∼ 500 erg cm s −1 and low outflow velocity, v ∼ 540 km s −1 , gives rise to absorption features due to O vii, O viii, N vi, N vii, and C vi. We also detected weak emission lines of He-like triplets from O vii and N vi ions, thus making Mrk 704 a Seyfert 1 galaxy with both warm absorption and emission. The emission lines are well described by two warm emitting, photoionized media with different densities but comparable ξ , suggesting discrete clouds of warm emission. The high-density phase (n e ∼ 10 13 cm −3 ) responsible for the resonance lines appears to outflow at high velocity ∼5000 km s −1 . The low-velocity, low-density phase is likely similar to the X-ray line emitting regions found in Seyfert 2 galaxies. The physical conditions of warm emitters and warm absorbers suggest that these clouds are similar but observed in absorption along our line of sight and in emission at other lines of sight. The unique line of sight passing close to the torus opening angle is likely responsible for the neutral partial covering absorption and our view of emission lines due to the suppressed continuum in this polar-scattered Seyfert 1 galaxy.

A highly accreting low-mass black hole hidden in the dust: Suzaku and NuSTAR observations of the NLS1 Mrk 1239

“…Polar-scattered Sy1s, including Mrk 1239, often show significant absorption features in the X-ray band, which is in agreement with the picture that our LOS passes close to their torus opening angles (e.g. Jiménez-Bailón et al 2008;Piconcelli et al 2013;Laha et al 2011;Newman et al 2021). For instance, the polar-scattered Sy1 Mrk 704 shows not only a partial covering neutral absorber with H ≈ 10 23 cm −2 and Cfact=0.22 but also two layers of warm absorbers that are associated with the broad line region (Laha et al 2011).…”

Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert galaxies - I. A global view and frequency of occurrence of warm absorbers.

“…• Mrk 704- Laha et al (2011) have found two discrete WA components with ξ ∼ 20 and ξ ∼ 500. Both these ionisation states and the ouflow velocities are comparable with our detections.…”

“…In our analysis we detect an additional component of WA with log ξ ∼ 3.13. Laha et al (2011) had detected a partially covering neutral absorber.…”

Extreme warm absorber variability in the Seyfert galaxy Mrk 704

“…During the revision of the present work, we became aware of a paper by Laha et al (2011) dealing with the analysis of the second XMM-Newton observation of Mrk 704. The results of their analysis are qualitatively similar to ours, the quantitative differences probably mostly related to the somewhat different spectral model adopted 3 .…”