Local AGN Survey (LASr): I. Galaxy sample, infrared colour selection and
  predictions for AGN within 100 Mpc
  In order to answer some of the major open questions in the fields of
supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH
growth, i.e., active galactic nuclei (AGN), is required. Thanks to deep all-sky
surveys, such as those by the Wide-field Infrared Survey Explorer (WISE) and
the Spectrum-Roentgen-Gamma (SRG) missions, this task is now becoming feasible
in the nearby Universe. Here, we present a new survey, the Local AGN Survey
(LASr), with the goal of identifying AGN unbiased against obscuration and
determining the intrinsic Compton-thick (CT) fraction. First, we construct the
most complete all-sky sample of galaxies within 100 Mpc from astronomical
databases (90% completeness for log M_star/M_sun ~9.4), four times deeper than
the current local galaxy reference, the Two Micron All-Sky Survey Redshift
Survey (2MRS), which turns out to miss 20% of known luminous AGN. These 49k
galaxies serve as parent sample for LASr, called LASr-GPS. It contains 4.3k
already known AGN, >=82% of these are estimated to have L(12um) < 10^42.3
erg/s, i.e., are low-luminosity AGN. As a first method for identifying
Seyfert-like AGN, we use WISE-based infrared colours, finding 221 galaxies at
L(12um) >= 10^42.3 erg/s to host an AGN at 90% reliability, This includes 61
new AGN candidates and implies and optical type 2 fraction of 50 to 71%. We
quantify the efficiency of this technique and estimate the total number of AGN
with L_int(2-10 keV) >= 10^42 erg/s in the volume to be 362^+145_-116
(8.6^+3.5_-2.8 10^-5 Mpc^-3). X-ray brightness estimates indicate the CT
fraction to be 40-55% to explain the Swift non-detections of the infrared
selected objects. One third of the AGN within 100 Mpc remain to be identified
and we discuss the prospects for the eROSITA all-sky survey.
