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Updated: Jul 30, 2026
11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Structure and evolution of the compact radio source in NGC 1275
J D Romney1, J M Benson, V Dhawan
1National Radio Astronomy Observatory, Socorro, NM 87801, USA.
Summary
Researchers studied the radio source 3C 84 in NGC 1275, revealing subluminal motions in its jet and a newly detected counterjet. This counterjet
Area of Science:
- * Astrophysics
- * Radio Astronomy
Background:
- * Investigating the fine-scale structure of the compact nucleus in the radio source 3C 84 (NGC 1275).
- * Long-term structural monitoring observations initiated in 1976.
Purpose of the Study:
- * To analyze subluminal motions within a jet-like region of 3C 84.
- * To investigate the nature and spectral properties of a newly discovered counterjet feature.
Main Methods:
- * Employing structural monitoring with very-long-baseline radio interferometry (VLBI).
- * Conducting multi-frequency observations (5 to 43 GHz) of the counterjet.
Main Results:
- * Detected subluminal motions in a diffuse jet region extending from a flat-spectrum core.
- * Discovered a counterjet feature in 1993, confirmed across five frequencies.
- * Observed a strong low-frequency cutoff in the counterjet, indicating an inverted spectrum.
Conclusions:
- * The counterjet's inverted spectrum is consistent with free-free absorption obscuring it from a surrounding volume.
- * This model suggests VLBI can probe parsec-scale accretion regions outside the radio jet.
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