Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 2016 | Submitted + Published
Journal Article Open

The CARMA Paired Antenna Calibration System: Atmospheric Phase Correction for Millimeter Wave Interferometry and its Application to Mapping the Ultraluminous Galaxy Arp 193


Phase fluctuations introduced by the atmosphere are the main limiting factor in attaining diffraction limited performance in extended interferometric arrays at millimeter and submillimeter wavelengths. We report the results of C-PACS, the Combined Array for Research in Millimeter-Wave Astronomy Paired Antenna Calibration System. We present a systematic study of several hundred test observations taken during the 2009–2010 winter observing season where we utilize CARMA's eight 3.5 m antennas to monitor an atmospheric calibrator while simultaneously acquiring science observations with 6.1 and 10.4 m antennas on baselines ranging from a few hundred meters to ~2 km. We find that C-PACS is systematically successful at improving coherence on long baselines under a variety of atmospheric conditions. We find that the angular separation between the atmospheric calibrator and target source is the most important consideration, with consistently successful phase correction at CARMA requiring a suitable calibrator located ≾6° away from the science target. We show that cloud cover does not affect the success of C-PACS. We demonstrate C-PACS in typical use by applying it to the observations of the nearby very luminous infrared galaxy Arp 193 in ^(12)CO(2-1) at a linear resolution of ≈70 pc (0".12 × 0".18), 3 times better than previously published molecular maps of this galaxy. We resolve the molecular disk rotation kinematics and the molecular gas distribution and measure the gas surface densities and masses on 90 pc scales. We find that molecular gas constitutes ~30% of the dynamical mass in the inner 700 pc of this object with a surface density ~10^4 M_⊙ pc^(−2); we compare these properties to those of the starburst region of NGC 253.

Additional Information

© 2016. The American Astronomical Society. Received 2013 December 18; accepted 2015 September 25; published 2016 January 7. We thank the referee for constructive comments and suggestions. Support for CARMA construction was derived from the Gordon and Betty Moore Foundation, the Kenneth T. and Eileen L. Norris Foundation, the James S. McDonnell Foundation, the Associates of the California Institute of Technology, the University of Chicago, the states of California, Illinois, and Maryland, and the National Science Foundation. Ongoing CARMA development and operations are supported by the National Science Foundation under a cooperative agreement, and by the CARMA partner universities. We acknowledge support from NSF AST-0838178. The funds for the additional hardware for the paired antennas were from a NASA CDDF grant, an NSF-Y1 Award, and the David and Lucile Packard Foundation. B.A.Z. wishes to acknowledge the Department of Astronomy at the University of Maryland, where most of this research was conducted. B.A.Z. also acknowledges partial support from NSF AST-1302954 (AAPF), NSF PHYS-1066293, and the hospitality of the Aspen Center for Physics. A. B. wishes to acknowledge partial support from NSF AST-0955836, a Cottrell Scholar award from the Research Corporation for Science Advancement, and the Humboldt Foundation. We thank M. S. Clemens and P. Alexander for kindly providing their reduced H i data cubes for comparison and analysis. We acknowledge the input and support in implementation of this experiment from Owens Valley Radio Observatory staff Dave Hawkins and Ira Snyder (correlator); Steve Scott, Andy Beard, and Rick Hobbs (software and computing); Michael Cooper, Ron Lawrence, Paul Rasmussen, Curt Giovanine, Steve Miller, and Andres Rizo (paired antenna pad construction and array operations); Brad Wiitala, Michael Laxen, Russ Keeney, Stan Hudson, and Mark Hodges (receivers and technical development); John Marzano, Gene Kahn, Mike Virgin, Mary Daniel, Lori McGraw, Cecil Patrick, and Terry Sepsey (general operations).

Attached Files

Published - Zauderer_2016p18.pdf

Submitted - 1410.5560v1.pdf


Files (7.9 MB)
Name Size Download all
3.1 MB Preview Download
4.7 MB Preview Download

Additional details

August 22, 2023
October 17, 2023