NIKA2 mapping and cross-instrument SED extraction of extended sources with Scanamorphos

TL;DR

This paper adapts the Scanamorphos algorithm for NIKA2 data to improve mapping of extended astronomical sources and combines Herschel and NIKA2 data for broadband SED analysis, addressing instrument-specific noise and coverage issues.

Contribution

It introduces a tailored version of Scanamorphos for NIKA2, optimized for extended sources, and develops a tool for consistent broadband SED extraction from combined Herschel and NIKA2 observations.

Findings

Effective noise subtraction for NIKA2 extended source mapping.

Successful combination of Herschel and NIKA2 data for broadband SEDs.

Demonstrated application on real astronomical data.

Abstract

The steps taken to tailor to NIKA2 observations the Scanamorphos algorithm (initially developed to subtract low-frequency noise from Herschel on-the-fly observations) are described, focussing on the consequences of the different instrument architecture and observation strategy. The method, making the most extensive use of the redundancy built in the multi-scan coverage with large arrays of a given region of the sky, is applicable to extended sources, while the pipeline is so far optimized for compact sources. An example of application is given. A related tool to build consistent broadband SEDs from 60 microns to 2 mm, combining Herschel and NIKA2 data, has also been developed. Its main task is to process the data least affected by low-frequency noise and coverage limitations (i.e. the Herschel data) through the same transfer function as the NIKA2 data, simulating the same scan geometry and applying the same noise and atmospheric signal as extracted from the 1 mm and 2 mm data.