Optical Spectroscopic Survey of High Latitude WISE Selected Sources

TL;DR

This optical spectroscopic survey of WISE-selected high-latitude sources characterizes galaxy and star densities, redshift distributions, and demonstrates the potential of WISE data for galaxy studies using Keck II observations.

Contribution

First spectroscopic survey of WISE-selected high-latitude sources, providing redshift and density measurements, and assessing WISE data's utility for galaxy research.

Findings

Median redshift of 0.33 for WISE sources with flux ≥120 μJy.

Galaxy density of 0.30 ± 0.02 per arcmin^2.

High success rate (>90%) in obtaining redshifts for targeted sources.

Abstract

We report on the results of an optical spectroscopic survey at high Galactic latitude (b\geq30{\deg}) of a sample of WISE-selected targets, grouped by WISE W1 ({\lambda}_eff = 3.4 \mum) flux, which we use to characterize the sources WISE detected. We observed 762 targets in 10 disjoint fields centered on ultra-luminous infrared galaxy (ULIRG) candidates using the DEIMOS spectrograph on Keck II. We find 0.30 \pm 0.02 galaxies arcmin^-2 with a median redshift of z=0.33 \pm 0.01 for the sample with W1 \geq 120 \muJy. The foreground stellar densities in our survey range from 0.23 \pm 0.07 arcmin^(-2) to 1.1 \pm 0.1 arcmin^(-2) for the same sample. We obtained spectra that produced science grade redshifts for \geq 90% of our targets for sources with W1 flux \geq 120 \muJy that also had i-band flux \geq 18 \muJy. We used for targeting very preliminary data reductions available to the team in August of 2010. Our results therefore present a conservative estimate of what is possible to achieve using WISE's Preliminary Data Release for the study of field galaxies.