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MULTI-FREQUENCY IMAGING ALGORITHMS AND SIMULATION OF SPACE VLBI USING VLA

MULTI-FREQUENCY IMAGING ALGORITHMS AND SIMULATION OF SPACE VLBI USING VLA S. Likhachev (1), L, Kogan(2), E. Fomalont(2), F. Owen(2) (1) Astro Space Center of P.N. Lebedev Physical Institute (2) National Radio Astronomical Observatory. Introduction

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MULTI-FREQUENCY IMAGING ALGORITHMS AND SIMULATION OF SPACE VLBI USING VLA

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  1. MULTI-FREQUENCY IMAGING ALGORITHMS AND SIMULATION OF SPACE VLBI USING VLA S. Likhachev (1), L, Kogan(2), E. Fomalont(2), F. Owen(2) (1) Astro Space Center of P.N. Lebedev Physical Institute (2) National Radio Astronomical Observatory Introduction New Multi-Frequency Synthesis (MFS) algorithms were developed and implemented in the Astro Space Locator (ASL) operating under MS Windows system. In comparison with existed MFS algorithms, developed earlier by Sault, Conway and Cornwell, the ASL's MFS can directly estimate the structure and spectra of radio sources for a few frequency bands. All the details of the algorithm can be found in [1]. MFS Image of M87.CLEAN image and spectral index map VLA Observation Parameters Test VLA observations (configuration D) of M87 (RA=12:28, Dec=12:40) took place on November 16th, 2005. There were 22 antennas enabled. Frequency bands: K (K1=21300, K2=22200, K3=23000 , K4=23400 MHz) и U (U1=14700, U1=15200 MHz) Total observation time were 3 hours. Restoration of image quality by means of MFS Goals of the VLA Experiment Multi-frequency synthesis (MFS) of a M87 at the reference frequency (21.3 GHz) with bandwidth of 7 GHz by means of a new class of the multi-frequency imaging (MFI) algorithms developed at ASC. Multi-frequency analysis (MFA) of M87. Estimation of a spectral index maps of the source on the same reference frequency. Comparison of the obtained results with the existing MFI-technologies at NRAO. Investigations of the improvement of image fidelity due to MFS. Tools Astro Space Center (ASC) has used ASL for Windows(ftp://www.asc.rssi.ru/outgoing/ASL/ASL_10) software MFS Data Processing Steps (ASL for Windows) Maps synthesis by means of self-calibration procedure for all six frequencies (14665, 15135, 21535, 21965, 22935, 23364 MHz). Synthesis of the image of M87 on the reference frequency (21535.1 MHz) by means of generalized linear multi-frequency deconvolution algorithm[1]. Spectral analysis of the image (spectral indexes map, spectrum of different parts of the image of M87). Spectral Artifacts M87. Comparison of the Spectral Indexes (two-frequency data processing: 14.6 и 23.3 GHz) References Likhachev, S. F.;Ladygin, V. A.;Guirin, I. A. Linear algorithms of multi-frequency image processing for VLBI, Radiophysics and Quantum Electronics, Volume 49, Issue 7, pp.499-505

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