The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei

Abstract

Citation for published item:qr¡ %EferneteD sF nd mos elmeidD gF nd vndtD rF nd rdD wF tF nd flokovi¡ D wF nd eostEulidoD tF eF @PHIUA 9he infrred to Ery orreltion spetr of unosured type I tive glti nuleiF9D wonthly noties of the oyl estronomil oietyFD RTW @IAF ppF IIHEIPTF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe use new X-ray data obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR), near-infrared (NIR) fluxes and mid-infrared (MIR) spectra of a sample of 24 unobscured type 1 active galactic nuclei (AGN) to study the correlation between various hard X-ray bands between 3 and 80 keV and the infrared (IR) emission. The IR to X-ray correlation spectrum (IRXCS) shows a maximum at ∼15-20 µm, coincident with the peak of the AGN contribution to the MIR spectra of the majority of the sample. There is also an NIR correlation peak at ∼2 µm, which we associate with the NIR bump observed in some type 1 AGN at ∼1-5 µm and is likely produced by nuclear hot dust emission. The IRXCS shows practically the same behaviour in all the X-ray bands considered, indicating a common origin for all of them. We finally evaluated correlations between the X-ray luminosities and various MIR emission lines. All the lines show a good correlation with the hard X-rays (ρ ≥ 0.7), but we do not find the expected correlation between their ionization potentials and the strength of the IRXCS.

Polycyclic aromatic hydrocarbons in Seyfert and star-forming galaxies

“…Groves, Dopita & Sutherland 2006). However, a recent study reported that [Ne II] emission line can be significantly contaminated by the AGN-dominated systems using a sample of unobscured type 1 AGN (García-Bernete et al 2017). Because of that, and as a sanity check, we also employ other ionization ratios involving emission lines such as [O IV] and [Ar II] (see Appendix C).…”

“…Spinoglio, Andreani & Malkan 2002;Ho & Keto 2007;Pereira-Santaella et al 2010). However, this emission line could be significantly contaminated by the AGN (García-Bernete et al 2017). These SFR indicators are mainly important in the vicinity of AGN-dominated systems where classical SF indicators normally fail.…”

The optical versus mid-infrared spectral properties of 82 Type 1 AGNs: coevolution of AGN and starburst

“…Because of the difficulties in decomposition of the narrow Hα, Hβ and [NII] lines in the initial sample of Type 1 AGNs, to check some relations between narrow lines, we also consider a sample of Type 2 AGNs, taken from the literature (more in Section 4.4). The sample is taken from Hernán-Caballero et al (2015) and García-Bernete et al (2016), as these authors performed the fitting of CASSIS spectra of ∼150 objects -Seyfert 2 galaxies, LINERs and HII regions, using deblendIRS routine (we use the same routine in this work). We took the fitting results that they obtained (spectral index, α and fractional contributions of AGN and PAH in the spectra -RAGN and RPAH, respectively) for all objects for which we found the log([OIII]/Hβ) and log([NII]/Hα) measurements in the other literature.…”

“…To confirm these doubts, taking into account that it is complicated to decompose the narrow lines in the Type 1 AGNs (see the Appendix A and Popović & Kovačević 2011), we chose a sample of Type 2 AGNs (see Table 2 and Section 2.2). We made another BPT diagram, composed from the various LINER, HII regions and Seyfert 2 galaxies, from the samples of Hernán-Caballero et al (2015) and García-Bernete et al (2016). That BPT diagram is shown in the Fig.…”

Does the mid-infrared–hard X-ray luminosity relation for active galactic nuclei depend on Eddington ratio?

“…It is well-known that active galactic nuclei (AGNs) show a positive "linear" correlation between the mid-infrared (IR) and the hard X-ray luminosity in a log-log space (e.g., Lutz et al 2004;Horst et al 2008;Fiore et al 2009;Gandhi et al 2009;Ichikawa et al 2012;Matsuta et al 2012;Asmus et al 2015;Mateos et al 2015;Isobe et al 2016;García-Bernete et al 2017;Ichikawa et al 2017). In the context of the AGN unified model (e.g., Antonucci 1993;Urry & Padovani 1995), the X-ray emission in an AGN is generated in a hot corona by inverse Comp-⋆ E-mail: toba@kusastro.kyoto-u.ac.jp ton scattering of thermal photons from an accretion disk (e.g., Sunyaev & Titarchuk 1980;Haardt & Maraschi 1991, 1993.…”