Calibration of coherently integrated visibilities

T. Hall; A. M. Jorgensen; D. Mozurkewich; J. T. Armstrong; H. R. Schmitt; E. K. Baines; D. Hutter

doi:10.1117/12.925818

12 September 2012 Calibration of coherently integrated visibilities

T. Hall, A. M. Jorgensen, D. Mozurkewich, J. T. Armstrong, H. R. Schmitt, E. K. Baines, D. Hutter

Proceedings Volume 8445, Optical and Infrared Interferometry III; 84453G (2012) https://doi.org/10.1117/12.925818
Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands

Abstract

Coherent integration is an analysis approach which, can greatly increase the SNR of optical interferometric visibilities compared to those computed by the traditional squared visibility power spectrum technique. Co- herent integration relies on phase-referencing, optimally through post-processing fringe-tracking, to effectively create long coherent integrations of the fringe. At the Navy Precision Optical Interferometer (NPOI) this phase- referencing is achieved by a combination of wavelength bootstrapping and baseline bootstrapping. The result is that the complex visibility with full phase information is retrieved and that the poor noise associated with the power spectrum approach is greatly reduced. For small visibilities, which are most important in resolving objects, the SNR can be improved sometimes by orders of magnitudes, sometimes making the difference between easy and practically impossible observations. The fringe-tracking portion of coherent integration is limited by the SNR of the tracking signal and the noise of that causes some fringe smearing which must be calibrated. In this paper we develop a theoretical model of the resulting fringe smearing and its correction. We then demonstrated its validity through simulation and on observations from the NPOI.

Citation Download Citation

T. Hall, A. M. Jorgensen, D. Mozurkewich, J. T. Armstrong, H. R. Schmitt, E. K. Baines, and D. Hutter "Calibration of coherently integrated visibilities", Proc. SPIE 8445, Optical and Infrared Interferometry III, 84453G (12 September 2012); https://doi.org/10.1117/12.925818

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available