Improving the identification of high-z Herschel sources with position priors and optical/NIR and FIR/mm photometric redshifts

TL;DR

This paper introduces a photometric method using position priors and multi-wavelength data to improve the detection and redshift estimation of high-redshift (U)LIRGs in Herschel survey fields.

Contribution

It presents a new procedure combining Spitzer/MIPS priors with optical/NIR and FIR/mm photometric redshifts for more accurate source identification and characterization.

Findings

Reliable detection of high-z (U)LIRGs above specified flux thresholds.

Effective use of combined priors and photometric redshifts for source counterpart assignment.

Demonstrated potential for improved high-redshift galaxy studies.

Abstract

We present preliminary results about the detection of high redshift (U)LIRGs in the Bullet cluster field by the PACS and SPIRE instruments within the Herschel Lensing Survey (HLS) Program. We describe in detail a photometric procedure designed to recover robust fluxes and deblend faint Herschel sources near the confusion noise. The method is based on the use of the positions of Spitzer/MIPS 24 um sources as priors. Our catalogs are able to reliably (5 sigma) recover galaxies with fluxes above 6 and 10 mJy in the PACS 100 and 160 um channels, respectively, and 12 to 18 mJy in the SPIRE bands. We also obtain spectral energy distributions covering the optical through the far-infrared/millimeter spectral ranges of all the Herschel detected sources, and analyze them to obtain independent estimations of the photometric redshift based on either stellar population or dust emission models. We exemplify the potential of the combined use of Spitzer position priors plus independent optical and IR photometric redshifts to robustly assign optical/NIR counterparts to the sources detected by Herschel and other (sub-)mm instruments.