The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder V. Rotational measurements of NGC 891

TL;DR

This paper presents an automated spectral feature finder for Herschel SPIRE FTS data, demonstrating its use in measuring the rotation of ionized and neutral gas in galaxy NGC 891, revealing correlated velocity profiles across different ISM phases.

Contribution

The paper introduces an automated spectral feature fitting routine for Herschel SPIRE FTS data and applies it to measure gas rotation in NGC 891, linking infrared and radio observations.

Findings

NII and CI gas velocities match HI and Halpha profiles.

Ionized and neutral gas show correlated rotation patterns.

Spectral feature finder effectively analyzes galaxy spectra.

Abstract

The ESA Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF) project is an automated spectral feature fitting routine developed within the SPIRE instrument team to extract all prominent spectral features from all publicly available SPIRE FTS observations. In this work, we demonstrate the use of the FF information extracted from three observations of the edge-on spiral galaxy NGC 891 to measure the rotation of NII and CI gas at Far-infrared frequencies in complement to radio observations of the HI 21cm line and the CO(1-0) transition as well as optical measurements of Halpha. We find that measurements of both NII and CI gas follow a similar velocity profile to that of HI and Halpha showing a correlation between neutral and ionized regions of the interstellar medium (ISM) in the disk of NGC 891.