1. November 2009, Lunch talk The most compact E configuration for the EVLA. L. Kogan, G. Stanzione, J. Ott, F. Owen National Radio Astronomy Observatory Socorro, NM USA

2. November 2009, Lunch talk Outline Why do we need the E configuration? Configuration figures of merit. The optimization of the configuration minimizing the worst positive side lobe. (Kogan 2000, IEEE Transaction on Antenna and Propagation, 48, 7, 1075. ) Specific features of optimization: VLA transporter, underground environment, “topography” constraints. Special cost concern. The results.

3. November 2009, Lunch talk E-config Science Drivers Galactic and Local HI HI is diffuse & extended, lose flux with interferometer Galactic HI, HI in bridges, tidal tails, ram pressure stripped gas Molecular Gas Galactic star forming regions and Nearby Galaxies with improved mosaicking Cosmic Web In CDM simulations: bridges between galaxies HI column density sensitivity of E-config <10 16 cm -2 Connections between galaxies and cosmic web Recombination lines of ionized material; wide, faint lines 3

4. November 2009, Lunch talk Radio Continuum & Magnetic Fields (Non-)thermal continuum emission in nearby objects: e.g. radio relics in clusters (ideally w/ LFS), Polarization in large-scale galactic outflows of nucleated Starbursts Radio Lobes Faint outer lobes of radio galaxies (e.g. Cen A), Jet-IGM interaction, matter and energy feedback Radio galaxies with recently shut-off engines SZ Effect and Cosmology Upscattering of CMB photons in hot cluster gas @30GHz entire cluster in FoV but still resolving structure Electron density distribution at all z Pulsar Searches Adequate number of synthesized beams over the fov for efficient processing 4

5. November 2009, Lunch talk Why do we need the most compact E-configuration? Compare with D configuration To get better Surface Brightness Sensitivity.

6. November 2009, Lunch talk Configuration figures of merit. Minimal side lobes Gaussian shape of the main beam Minimal gaps in the UV coverage Others Optimizing figures of merit other than “Minimal side lobes” improves the side lobes level implicitly, but a direct minimal side lobes optimization may produce better result. We optimize the configuration minimizing the maximum positive side lobe inside of the primary beam!

7. November 2009, Lunch talk

14. The Shadowing.

15. November 2009, Lunch talk

16. Conclusions 1.The designed E-configuration array has a maximum positive side lobes ~12% for snapshot with natural weighting. VLA-D for comparison has ~60% 2.The brightness temperature sensitivity is expected ~10 times better than VLA-D 3.Positions of all antennas satisfy requirements of the loading/reloading by the VLA transporter. 4.Positions of all antennas satisfy all constrains including underground environment. 5.The cost of the array is optimized, because the 11 existed pads are used; the existing track at the north-east sector is used; Only one extra track is added…. 6.More job may be needed: to simplify junctions of the new north-west track with the existed tracks (north and south-west). to add the hybrid configuration for the Galactic Center observation.

17. November 2009, Lunch talk THANKS

18. November 2009, Lunch talk Ultracompact E-configuration 16 new pads added at the center of the EVLA, +4 for hybrid Enhanced surface brightness sensitivity for all bands (1h E-conf: 1  of 50-100  K in continuum) Reduced sidelobe response Improved mosaicking capabilities Fill in the gap in uv space between GBT and D-config Better phase stability, potentially more time available at high frequencies in otherwise non-ideal conditions 18

19. November 2009, Lunch talk E-configuration Easy implementation: steel, concrete, fibers, power, communication Subcontractors could do most of the work Zero risk Operational Costs: ~$360K/yr 19