Talk abstract details
Obscuration in low-luminosity active galactic nuclei
Abstract
The obscuring material is the cornerstone to explain the variety of the active galactic nuclei (AGN) under the unified model (Antonucci 1993). In the last years, studies at mid-infrared have shown that Type-2 AGN might have more clumps and wider torus angular distributions than Type-1 AGN. In the very end of the AGN luminosity function LINERs are finally believed to have an AGN in their centers. Moreover, it has been proposed that LINERs could be a population where obscuration could be specially important among AGN, according to its X-ray properties. However, is this obscuring material coming from the so-called optically-thick torus? is it related with the host galaxy? is it the responsible for the optical classification of these sources?
The best way to understand the role, amount, and nature of the obscuration in LINERs is through mid-infrared data since the absorbed emission coming from optical and UV photons is re-emitted at these wavelengths. However, a spatially resolved study is crucial to distinguish between the properties of the central AGN and its host galaxy. Moreover, LINERs because of its low-luminosity are faint sources. Thus, a sensitive instrument is needed to collect enough photons in a reasonable amount of time. Thus, the imminent light of CanariCam at GTC,
open for the first time the possibility to understand the nature of these mysterious objects. Our sample comprises the biggest sample analyzed at X-ray frequencies with 82 LINERs where also a multiwavelength analysis is already done by our group. This proposal succeeded as part of the half-risk allocated time when this was offered by the CAT. As a preparatory for that moment, we have undertaken a campaign to observe some of them with VISIR instrument located at the VLT telescope. Together with archival data we have a sample of 18 LINERs. For those in which we were able to detect the source, we have measured fluxes at several filters and compared their morphologies with other wavelengths. We will present in this talk the main results of this ongoing project.
The best way to understand the role, amount, and nature of the obscuration in LINERs is through mid-infrared data since the absorbed emission coming from optical and UV photons is re-emitted at these wavelengths. However, a spatially resolved study is crucial to distinguish between the properties of the central AGN and its host galaxy. Moreover, LINERs because of its low-luminosity are faint sources. Thus, a sensitive instrument is needed to collect enough photons in a reasonable amount of time. Thus, the imminent light of CanariCam at GTC,
open for the first time the possibility to understand the nature of these mysterious objects. Our sample comprises the biggest sample analyzed at X-ray frequencies with 82 LINERs where also a multiwavelength analysis is already done by our group. This proposal succeeded as part of the half-risk allocated time when this was offered by the CAT. As a preparatory for that moment, we have undertaken a campaign to observe some of them with VISIR instrument located at the VLT telescope. Together with archival data we have a sample of 18 LINERs. For those in which we were able to detect the source, we have measured fluxes at several filters and compared their morphologies with other wavelengths. We will present in this talk the main results of this ongoing project.