Using VLA/GBT Data Combined with a New Interferometer and Single-Dish Joint Deconvolution Technique to Model Radio Halos of Galaxies
Abstract
We present preliminary results from a new joint deconvolution algorithm we use to combine wideband On-The-Fly (OTF) Robert C. Byrd Green Bank Telescope (GBT) data with Karl G. Jansky Very Large Array (JVLA) data from the Continuum Halos in Nearby Galaxies - an EVLA Survey (CHANG-ES). This technique feathers wideband single-dish (SD) data with interferometric (INT) data within an iterative image reconstruction scheme and solves the missing short-spacings problem, while also supporting imaging options such as multi-term multi-frequency synthesis, multi-scale modeling, and joint mosaicing. By jointly deconvolving SD and INT data, we avoid burning in negative bowls and we retain the absolute flux density at zero spacing in the uv-plane, both of which are problematic when imaging INT-only observations of large-scale diffuse emission. We apply this combination technique to create a Stokes I C-band (6 GHz) continuum image and a spectral index map of the nearby edge-on galaxy NGC 891 using data from the CHANG-ES project. This galaxy features a well characterized lagging gaseous halo, where the rotation velocity of the gas decreases with increasing height from the midplane. We use these images to model nonthermal halo radial pressure gradients, with the goal of understanding whether such pressure gradients can explain the amplitude of the lag. In the future, we plan to extend our analysis to a subsample of CHANG-ES galaxies with measured lags.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23326004B