| Author(s) and Co-Author(s) with Affiliation: Aashirbad Sethi(Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560 034, Karnataka, India), Shaik Sayuf(Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560 034, Karnataka, India), Indrajit Vittal Barve(Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560 034, Karnataka, India), Kathiravan C(Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560 034, Karnataka, India), Ramesh R(Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560 034, Karnataka, India) |
| Abstract: The Gauribidanur Radioheliograph (GRAPH) is a T-shaped interferometric array dedicated to observing the solar corona in the frequency range 40-130 MHz. It produces two-dimensional images at two spot frequencies presently. The frequency range corresponds to a heliocentric height of approximately 1.2~3.0 Rs (Rs = photospheric radius), the inner to middle corona, wherein the coronal transients that can affect the geospace originate.
The existing AIPS-based pipeline generates Stokes I and Stokes V images from a FITS file. Observatories around the world have adopted a new format called the Measurement Set (MS), a standard directory-based file format for storing interferometric and single-dish data, acting as a relational database for astronomical observations, using the NRAO’s Common Astronomy Software Applications (CASA). We have redefined our imaging pipeline (CASA-GRAPH), which utilizes Python-based tools to write CASA MS files from daily observations of the Sun and other sources. We are currently in the preliminary stages of development for generating calibrators and Stokes I images of the Sun.
We discuss the features of the CASA-GRAPH, including flagging of RFI on short and long baselines, customized calibration techniques, and subsequent imaging of the Solar Corona. Our future plan is to develop a fully automated pipeline to produce Stokes I and Stokes V images from daily observations.
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