North Ecliptic Pole multi-wavelength survey : new optical data with Hyper Suprime-Cam and near-future prospects with eROSITA

TL;DR

This paper reports on new optical imaging data from Hyper Suprime-Cam and discusses future prospects with eROSITA for studying obscured galaxies and AGNs in the North Ecliptic Pole region using multi-wavelength surveys.

Contribution

It presents the first deep optical images covering the NEP-Wide field with Hyper Suprime-Cam and explores future X-ray observations with eROSITA for enhanced AGN detection.

Findings

Over 5000 optical counterparts of mid-IR sources identified.

Deep optical imaging enables detailed SED analysis of obscured galaxies.

Future eROSITA data will significantly increase detected Compton-thick AGN candidates.

Abstract

The AKARI North Ecliptic Pole (NEP) survey consists of two survey projects: NEP-Deep (0.5 sq.deg) and NEP-Wide (5.4 sq.deg), providing with tens of thousands of galaxies. A continuous filter coverage in the mid-infrared wavelengths (7, 9, 11, 15, 18 and 24 $\mu$m) is unique to diagnose the contributions from dusty star-formation activity and AGNs. Here we present current status focused on the newly obtained optical images and near-future prospects with a new X-ray telescope. Hyper Suprime-Cam on Subaru telescope is a gigantic optical camera with huge Field of View (FoV). Thanks to the wide FoV, we successfully obtained deep optical images at g, r, i, z and Y-bands covering most of the NEP-Wide field. Using the deep optical images, we identified over 5000 optical counterparts of the mid-IR sources, presumably deeply obscured galaxies in NEP-Wide field. We also investigated properties of these infrared sources with SED-fitting. eROSITA, to be launched early 2018, is a new all-sky X-ray survey telescope, and expected to conduct ultra deep 2-10 keV imaging toward NEP. We expect unprecedentedly numerous Compton-thick AGN candidates when combined with the multi-wavelength data in NEP region.