HectoMAP: The Complete Redshift Survey (Data Release 2)

TL;DR

HectoMAP is a comprehensive redshift survey of over 95,000 galaxies that provides valuable data for studying galaxy populations, clusters, and the cosmic web, with improved photometric redshift comparisons and complete magnitude limits.

Contribution

This work presents the second data release of HectoMAP, offering extensive spectroscopic data and demonstrating its integration with photometric surveys for advanced cosmological studies.

Findings

Survey covers 54.64 deg² with 95,403 galaxies.

Achieves 81% completeness for certain galaxy populations.

Demonstrates improved photometric redshift accuracy with HSC-SSP.

Abstract

HectoMAP is a dense redshift survey of 95,403 galaxies based primarily on MMT spectroscopy with a median redshift $z = 0.345$. The survey covers 54.64 square degrees in a 1.5$^\circ$ wide strip across the northern sky centered at a declination of 43.25$^\circ$. We report the redshift, the spectral indicator D$_{n}$4000, and the stellar mass. The red selected survey is 81\% complete for 55,962 galaxies with $(g-r) > 1$ and $r <20.5$; it is 72\% complete for 32,908 galaxies with $(g-r) > 1$, $(r-i) > 0.5$ and $20.5 < r < 21.3$. Comparison of the survey basis SDSS photometry with the HSC-SSP photometry demonstrates that HectoMAP provides complete magnitude limited surveys based on either photometric system. We update the comparison between the HSC-SSP photometric redshifts with HectoMAP spectroscopic redshifts; the comparison demonstrates that the HSC-SSP photometric redshifts have improved between the second and third data releases. HectoMAP is a foundation for examining the quiescent galaxy population (63\% of the survey), clusters of galaxies, and the cosmic web. HectoMAP is completely covered by the HSC-SSP survey, thus enabling a variety of strong and weak lensing investigations.