Title: The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei,
Abstract: We 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 micron, coincident with the peak of the AGN contribution to
the MIR spectra of the majority of the sample. There is also a NIR correlation
peak at ~2 micron, which we associate with the NIR bump observed in some type 1
AGN at ~1-5 micron 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 (rho>0.7), but we do not find the
expected correlation between their ionization potentials and the strength of
the IRXCS.