The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Medium-Band optical imaging and high quality 32-band photometric redshifts in the ECDF-S

TL;DR

This paper presents deep medium-band optical imaging and high-quality 32-band photometric redshifts in the ECDF-S, enabling precise galaxy redshift measurements and galaxy population analysis in a well-studied extragalactic field.

Contribution

The study introduces a comprehensive 32-band photometric catalog combining Subaru medium-band and other data, achieving highly accurate photometric redshifts, especially at 0.1<z<1.2 and z>3.5.

Findings

Photometric redshifts have a 1 sigma scatter of 0.007 for 0.1<z<1.2.

Red sequence and blue cloud are clearly identified in color-magnitude diagrams.

Approximately 20% of red-sequence galaxies show dust emission evidence.

Abstract

We present deep optical 18-medium-band photometry from the Subaru telescope over the ~30' x 30' Extended Chandra Deep Field-South (ECDF-S), as part of the Multiwavelength Survey by Yale-Chile (MUSYC). This field has a wealth of ground- and space-based ancillary data, and contains the GOODS-South field and the Hubble Ultra Deep Field. We combine the Subaru imaging with existing UBVRIzJHK and Spitzer IRAC images to create a uniform catalog. Detecting sources in the MUSYC BVR image we find ~40,000 galaxies with R_AB<25.3, the median 5 sigma limit of the 18 medium bands. Photometric redshifts are determined using the EAZY code and compared to ~2000 spectroscopic redshifts in this field. The medium band filters provide very accurate redshifts for the (bright) subset of galaxies with spectroscopic redshifts, particularly at 0.1 < z < 1.2 and at z > 3.5. For 0.1 < z < 1.2, we find a 1 sigma scatter in \Delta z/(1+z) of 0.007, similar to results obtained with a similar filter set in the COSMOS field. As a demonstration of the data quality, we show that the red sequence and blue cloud can be cleanly identified in rest-frame color-magnitude diagrams at 0.1 < z < 1.2. We find that ~20% of the red-sequence-galaxies show evidence of dust-emission at longer rest-frame wavelengths. The reduced images, photometric catalog, and photometric redshifts are provided through the public MUSYC website.