The 1.4 mm Core of Centaurus A: First VLBI Results with the South Pole Telescope

Centaurus A (Cen A) is a bright radio source associated with the nearby galaxy NGC 5128 where high-resolution radio observations can probe the jet at scales of less than a light day. The South Pole Telescope (SPT) and the Atacama Pathfinder Experiment performed a single-baseline very-long-baseline i...

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Bibliographic Details
Published in:The Astrophysical journal 2018-07, Vol.861 (2), p.129
Main Authors: Kim, Junhan, Marrone, Daniel P., Roy, Alan L., Wagner, Jan, Asada, Keiichi, Beaudoin, Christopher, Blanchard, Jay, Carlstrom, John E., Chen, Ming-Tang, Crawford, Thomas M., Crew, Geoffrey B., Doeleman, Sheperd S., Fish, Vincent L., Greer, Christopher H., Gurwell, Mark A., Henning, Jason W., Inoue, Makoto, Keisler, Ryan, Krichbaum, Thomas P., Lu, Ru-Sen, Muders, Dirk, Müller, Cornelia, Nguyen, Chi H., Ros, Eduardo, SooHoo, Jason, Tilanus, Remo P. J., Titus, Michael, Vertatschitsch, Laura, Weintroub, Jonathan, Zensus, J. Anton
Format: Article
Language:English
Subjects:
Astrophysics
black hole physics
Brightness temperature
Correlation analysis
Density
Fluctuations
Flux density
Galaxies
galaxies: active
galaxies: individual (Centaurus A)
Interferometry
Particle energy
Radio observation
Radio sources (astronomy)
Relativistic particles
South Pole
submillimeter: general
techniques: high angular resolution
techniques: interferometric
Very long base interferometry
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Summary:Centaurus A (Cen A) is a bright radio source associated with the nearby galaxy NGC 5128 where high-resolution radio observations can probe the jet at scales of less than a light day. The South Pole Telescope (SPT) and the Atacama Pathfinder Experiment performed a single-baseline very-long-baseline interferometry (VLBI) observation of Cen A in 2015 January as part of VLBI receiver deployment for the SPT. We measure the correlated flux density of Cen A at a wavelength of 1.4 mm on a ∼7000 km (5 Gλ) baseline. Ascribing this correlated flux density to the core, and with the use of a contemporaneous short-baseline flux density from a Submillimeter Array observation, we infer a core brightness temperature of 1.4 × 1011 K. This is close to the equipartition brightness temperature, where the magnetic and relativistic particle energy densities are equal. Under the assumption of a circular Gaussian core component, we derive an upper limit to the core size φ = 34.0 1.8 as, corresponding to 120 Schwarzschild radii for a black hole mass of 5.5 × 107 M .
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aac7c6