1 / 17

EVLA

EVLA. Bryan Butler. What is the EVLA?. keep VLA antennas, pads, rail system, buildings, etc…, i.e., all the infrastructure upgrade: Front Ends (feeds + Rx) LO Data transmission Correlator software add antennas & pads (Phase II). What is the EVLA?. Results:

ailsa
Download Presentation

EVLA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EVLA Bryan Butler

  2. What is the EVLA? • keep VLA antennas, pads, rail system, buildings, etc…, i.e., all the infrastructure • upgrade: • Front Ends (feeds + Rx) • LO • Data transmission • Correlator • software • add antennas & pads (Phase II)

  3. What is the EVLA? • Results: • continuous frequency coverage from 1 - 50 GHz • improved sensitivity: 1 Jy in 12 hours • higher resolution: 10 masec @ 20 GHz (Phase II) • better brightness sensitivity: 0.1 mK @ 10 GHz @ 10" • more flexible correlator (WIDAR): 16384 channels available at full bandwidth, 4.2 million channels at highest spectral resolution; independently tunable subchannels • dynamic scheduling • much easier for the astronomer to use

  4. EVLA Sensitivity

  5. Phased Deployment Split into two “phases” - Phase I and Phase II, for strategic reasons. Phase I - hardware, electronics, correlator, software currently funded (details on next slide) Phase II - 8 new antennas, 20 new close-packed pads proposal just went in to NSF

  6. Phase I Science Themes • Four science themes chosen to underscore the capabilities of the EVLA, and radio astronomy: • The Magnetic Universe • The Obscured Universe • The Transient Universe • The Evolving Universe

  7. Phase I Specific Science Goals The Phase I proposal identified the following key science goals: • Measuring the 3-dimensional motions of ionized gas and stars in the center of the Galaxy. • Conducting unbiased searches for redshifted atomic and molecular absorption lines. • Measuring the 3-dimensional structure of magnetic fields on the sun. • Mapping the changing structure of the dynamic heliosphere. • Accurate positions, sizes, and expansion estimates of ~100 GRBs every year. • Mapping the magnetic fields in individual galaxy clusters. • Observing ambipolar diffusion and thermal jet motions in young stellar objects. • Measuring the rotation speeds of asteroids.

  8. Phase I Status • A proposal for $50M (2000 dollars) was submitted to the NSF in May 2000. • After approval by the NSB, funding from the NSF began in 2001, at a rate of $5M/year, with completion anticipated by 2012. • Canadian government approval for full correlator funding (US$14.4M) came in 2003. • Mexican funds $2M are also available. • Prototyping is now well advanced. First light was achieved in October 2003; first fringes in April 2004. • Outfitting with full production electronics will begin later this year. • Fully operational by 2012.

  9. Phase I Status

  10. Phase I Status

  11. First Light • EVLA achieved first light in October, 2003. • X-Band (8 – 12 GHz) • Bandwidth of 1 GHz. • Utilized all new EVLA electronics • Drift scan of the moon: expected antenna temperature of about 200 K.

  12. Phase II Status • The Phase II (completion) proposal was submitted to the NSF in April 2004. • Lengthy approval process expected. • Competition for MRE funding very stiff. • If approved, a 7-yr timescale will be needed: if we start in 2005, can complete by 2012.

  13. The Frequency-Resolution Plane

  14. Why both EVLA and ALMA? • Non-thermal processes emit at cm-wavelengths • Lower dust opacity at long  • Cosmic expansion shifts spectrum to longer 

  15. Why both EVLA and ALMA? • At z > 5 or so, only the high energy transitions of CO will be available to ALMA

  16. Why both EVLA and ALMA? • The inner portions of dense star-formation regions are optically thick at mm 

  17. EVLA - WVR The EVLA, like ALMA, will need phase correction. Current efforts are very encouraging see Claire’s poster…

More Related