Juhun Kwak, John Podczerwinski, Peter Timbie, Reza Ansari, John Marriner, Albert Stebbins, Fengquan Wu, Haotian Cao, Xuelei Chen, Kai He, Jixia Li, Shijie Sun, Jiacong Zhu
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引用次数: 0
Abstract
The visibilities measured by radio astronomical interferometers include non-astronomical correlated signals that arise from the local environment of the array. These correlated signals are especially important in compact arrays such as those under development for 21\,cm intensity mapping. The amplitudes of the contaminated visibilities can exceed the expected 21\,cm signal and represent a significant systematic effect. We study the receiver noise radiated by antennas in compact arrays and develop a model for how it couples to other antennas. We apply the model to the Tianlai Dish Pathfinder Array (TDPA), a compact array of 16, 6-m dish antennas. The coupling model includes electromagnetic simulations, measurements with a network analyzer, and measurements of the noise of the receivers. We compare the model to drift-scan observations with the array and set requirements on the level of antenna cross-coupling for 21\,cm intensity mapping instruments. We find that for the TDPA, cross-coupling would have to be reduced by TBD orders of magnitude in order to contribute negligibly to the visibilities.
期刊介绍:
The Journal of Astronomical Instrumentation (JAI) publishes papers describing instruments and components being proposed, developed, under construction and in use. JAI also publishes papers that describe facility operations, lessons learned in design, construction, and operation, algorithms and their implementations, and techniques, including calibration, that are fundamental elements of instrumentation. The journal focuses on astronomical instrumentation topics in all wavebands (Radio to Gamma-Ray) and includes the disciplines of Heliophysics, Space Weather, Lunar and Planetary Science, Exoplanet Exploration, and Astroparticle Observation (cosmic rays, cosmic neutrinos, etc.). Concepts, designs, components, algorithms, integrated systems, operations, data archiving techniques and lessons learned applicable but not limited to the following platforms are pertinent to this journal. Example topics are listed below each platform, and it is recognized that many of these topics are relevant to multiple platforms. Relevant platforms include: Ground-based observatories[...] Stratospheric aircraft[...] Balloons and suborbital rockets[...] Space-based observatories and systems[...] Landers and rovers, and other planetary-based instrument concepts[...]