Lack of Interaction between the Dust Grains and the Anomalous Radio Jet in the Nearby Spiral Galaxy NGC 4258

TL;DR

This study used multi-wavelength data to investigate whether the radio jet in NGC 4258 destroys dust, finding no evidence of interaction at the observed spatial scales.

Contribution

It provides the first detailed analysis of dust-jet interaction in NGC 4258 using high-resolution infrared and radio data, showing no detectable dust destruction.

Findings

No correlation between 8 micron emission and radio jet suggests lack of dust destruction.

Dust destruction, if any, occurs at scales below current observational resolution.

8 micron emission traces the galactic plane and is unaffected by the jet.

Abstract

We obtained Spitzer/IRAC 3.6-8 micron images of the nearby spiral galaxy NGC 4258 to study possible interactions between dust and the radio jet. In our analysis we also included high-resolution radio continuum, H-alpha, CO, and X-ray data. Our data reveal that the 8 micron emission, believed to originate largely from PAH molecules and hot dust, is an excellent tracer of the normal spiral structure in NGC 4258, and hence it originates from the galactic plane. We investigated the possibility of dust destruction by the radio jet by calculating correlation coefficients between the 8 micron and radio continuum emissions along the jet in two independent ways, namely (i) from wavelet-transformed maps of the original images at different spatial scales, and (ii) from one-dimensional intensity cuts perpendicular to the projected path of the radio jet on the sky. No definitive sign of a correlation (or anticorrelation) was detected on relevant spatial scales with either approach, implying that any dust destruction must take place at spatial scales that are not resolved by our observations.