Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud

TL;DR

This paper presents a large-scale, velocity-resolved [CII] emission map of the Orion molecular cloud, detailing observation, calibration, and data reduction techniques, and explores the ISM processes and stellar feedback effects in star-forming regions.

Contribution

It introduces new calibration and data reduction methods for large-scale [CII] mapping and demonstrates their application in studying ISM dynamics and stellar feedback.

Findings

A square-degree [CII] map with 0.3 km/s spectral resolution is provided.

Discussion of [CII] interaction with molecular clouds and feedback mechanisms.

Comparison with previous Herschel/HIFI data highlights calibration improvements.

Abstract

Context. The [CII] 158micron far-infrared fine-structure line is one of the dominant cooling lines of the star-forming interstellar medium (ISM). Hence [CII] emission originates in and thus can be used to trace a range of ISM processes. Velocity-resolved large-scale mapping of [CII] in star-forming regions provides a unique perspective of the kinematics of these regions and their interactions with the exciting source of radiation. Aims. We explore the scientific applications of large-scale mapping of velocity-resolved [CII] observations. With the [CII] observations, we investigate the effect of stellar feedback on the ISM. We present the details of observation, calibration, and data reduction using a heterodyne array receiver mounted on an airborne observatory. Results. A square-degree [CII] map with a spectral resolution of 0.3 km/s is presented. The scientific potential of this data is summarized with discussion of mechanical and radiative stellar feedback, filament tracing using [CII], [CII] opacity effects, [CII] and carbon recombination lines, and [CII] interaction with the large molecular cloud. The data quality and calibration is discussed in detail, and new techniques are presented to mitigate the effects of unavoidable instrument deficiencies (e.g. baseline stability) and thus to improve the data quality. A comparison with a smaller [CII] map taken with the Herschel/Heterodyne Instrument for the Far-Infrared (HIFI) spectrometer is presented.