Atmospheric Phase Correction using CARMA-PACS: High Angular Resolution Observations of the FU-Orionis star PP 13S*

TL;DR

This paper demonstrates the use of CARMA-PACS atmospheric phase correction to enhance high-resolution millimeter observations of the circumstellar disk around FU-Orionis star PP 13S*, improving data quality and enabling detailed disk modeling.

Contribution

The paper introduces the C-PACS technique for atmospheric correction in millimeter interferometry and applies it to observe and model the PP 13S* disk with improved sensitivity and resolution.

Findings

Increased peak flux by 1.6 times after correction

Reduced image noise by 36%

Measured disk mass of 0.06 solar masses

Abstract

We present 0.15" resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU-Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best fit model corresponds to 0.06 \msun, which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability.