# The NuSTAR view of the true Type 2 Seyfert NGC3147

## TL;DR

This study uses NuSTAR observations to confirm that NGC3147 is a true Type 2 Seyfert galaxy, showing an unobscured X-ray spectrum and lacking a broad-line region, with variability supporting an unobscured view.

## Contribution

First NuSTAR observation of NGC3147 providing strong evidence that it is an unobscured, true Type 2 Seyfert galaxy with no broad-line region.

## Key findings

- X-ray spectrum characterized by a simple power-law with no additional components
- Significant variability on weekly timescales supports unobscured line-of-sight
- Alternative Compton-thick scenario is strongly disfavoured

## Abstract

We present the first NuSTAR observation of a 'true' Type 2 Seyfert galaxy. The 3-40 keV X-ray spectrum of NGC3147 is characterised by a simple power-law, with a standard {\Gamma}~1.7 and an iron emission line, with no need for any further component up to ~40 keV. These spectral properties, together with significant variability on time-scales as short as weeks (as shown in a 2014 Swift monitoring campaign), strongly support an unobscured line-of-sight for this source. An alternative scenario in terms of a Compton-thick source is strongly disfavoured, requiring an exceptional geometrical configuration, whereas a large fraction of the solid angle to the source is filled by a highly ionised gas, whose reprocessed emission would dominate the observed luminosity. Moreover, in this scenario the implied intrinsic X-ray luminosity of the source would be much larger than the value predicted by other luminosity proxies, like the [OIII]{\lambda}5007 emission line extinction-corrected luminosity. Therefore, we confirm with high confidence that NGC3147 is a true Type 2 Seyfert galaxy, intrinsically characterised by the absence of a BLR.