학술논문
The 1.4 mm core of Centaurus A: First VLBI results with the South Pole Telescope
Document Type
Working Paper
Author
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
Source
Subject
Language
Abstract
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 (APEX) performed a single-baseline very-long-baseline interferometry (VLBI) observation of Cen A in January 2015 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 $\sim$7000 km (5 G$\lambda$) 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 $1.4 \times 10^{11}$ 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 $\phi = 34.0 \pm 1.8~\mu\textrm{as}$, corresponding to 120 Schwarzschild radii for a black hole mass of $5.5 \times 10^7 M_{\odot}$.
Comment: 9 pages, 5 figures, accepted for publication in ApJ
Comment: 9 pages, 5 figures, accepted for publication in ApJ