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Coordinated High |b| Drift Survey

Coordinated High |b| Drift Survey. Basics: Combination of 12 s/beam and 60 s/beam surveys High latitude sky (wait for low latitude for commensal) 100 MHz adequate (WAPPs ok) Limited-azimuth drift scan technique (simplest) Lays groundwork for deeper surveys

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Coordinated High |b| Drift Survey

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  1. Coordinated High |b| Drift Survey • Basics: • Combination of 12 s/beam and 60 s/beam surveys • High latitude sky (wait for low latitude for commensal) • 100 MHz adequate (WAPPs ok) • Limited-azimuth drift scan technique (simplest) • Lays groundwork for deeper surveys • Involves 30+ astronomers with wide range of interests • Precursor proposal A1946 highly ranked (“A”) • Early science potential: • M33 region • NGC 784 group of dwarfs • Leo I group region • Swath across heart of Virgo, perpendicular to Supergalactic plane • (Possible) blind HI absorption • Surprises

  2. Anti-Virgo Direction

  3. Virgo Direction

  4. Coordinated High |b| Drift Survey • Science objectives • What science goals will the proposed survey address? • How will the proposed survey improve on previous surveys? • What science goals will the proposed survey NOT address? • What are our "early science" goals (2 year timeframe)? • Possible PhD theses?

  5. Science goals, follow-up • Strategy/planning of Arecibo follow-up observations • Detection verification • New discoveries...? • Deeper sampling of selected regions? • Coordination with small ALFA projects • How will this work? What is our position? Should we make suggestion to NAIC on guidelines? • Coordination/verification of complementarity; How can we insure that small datasets can be incorporated into our larger one to increase solid angle coverage? • Coordination of complementary observations • Definition of objectives • Existing datasets (SDSS, GALEX, etc) what do we need? who? • Acquisition of new datasets: what do we need? who? • Non-Arecibo observations of new discoveries

  6. Instrument/Backends • ALFA characteristics • System specifications: updates • System performance at AO: reality sets in… • Is AO staff performing all calibration/testing we need? • System optimization for our needs? • How do we communicate with NAIC on this? • What WAPP configuration should be adopted and what are the tradeoffs in terms of spectral resolution, bit sampling, bandwidth? • Is 100 MHz required? Why or why not? (The digitizers see 100 MHz anyway.) • Is 50 MHz enough? Why or why not? There is rfi below 1375 MHz (airport radars and Puntas Salinas hopping radar). • Is 5.5 km/s resolution enough? Why or why not? • Should we conduct entire survey with WAPPS or move to new spectrometer when it's ready? (We don't need to answer this yet) • What are NAIC plans for the 2nd generation spectrometer? Availability date?

  7. Drift scan technique/tiling the sky • We propose to conduct drift scans at very limited azimuth orientations of "tiles" 20 min in RA by 4 deg in Dec. • Is this the right approach? • Should the fall VAVA' strip be shifted east by one tile; two tiles? • Best configuration: rotate arm or rotate array? • The +18d strip will be conducted at a different orientation than the other strips. How do we verify/validate that this differences introduces no biases/systematics? • Precursor/share-risk observations A 1946 • Will be scheduled in Jul-Aug • Any modifications to strategy? • Who will observe (on site)? • Data processing? • Assessment of results?

  8. Observing who, when, where • Observing issues • Scheduling: Who decides on schedule on short timescales (<~1-2 days)? • Observing logs: Who keeps records daily? Access? • Observing: On-site? Remote? Absentee? Backup plan (in case of net failure)? • What are our expectations of how this will work and what the responsibilities are? • Certainly at the beginning, someone will have to be on site. It may be that later on, observing can be done remotely. But someone does need to take the responsibility to keep track. • Data quality verification: Standards? Timescale? Who? How?

  9. Bandpass/continuum calibration • Bandpass calibration • Regular observation of selected continuum sources? • Firing the cal? How often? How long? • NAIC needs to provide software for this; it almost worked in Jan 04 • In-scan cross calibration with NVSS? • Bandpass/standing wave removal • best technique: 1-d or 2-d? • galactic HI/low velocities • software development for this task? • Continuum sources • Continuum catalog • Continuum subtraction • Transient detection? Coordination with others? • Absorption lines?

  10. RFI identification/excision • RFI expectations and effects • What RFI can we expect in the 50 or 100 MHz bands? • FAA radars plus hopping Puntas Salinas radar. They will be there; unless we want to use the radar blanker (slows things too much?) we have to live with them. • What are its characteristics? • Limitations on science goals or not? • RFI-related techniques • Beam-to-beam correlation • Sub-beam sampling (time domain) • Cross-polarization • Excision techniques: options, algorithm development? • When should they be applied?

  11. Software issues • Gridding • best algorithms • weighting schemes • platform? • what options to allow, what to save, etc? • Signal detection algorithms • Algorithm development: Fourier domain? Peak flux? Other? • Platform? • Verification? • HI catalog: parameter extraction, astrometry • Data reduction process • Distributed ("assembly line") or shared process ("pipeline")? • Coordination/management? • Verification/validation? • General software issues • Platform: IDL? • Data format: SDFITS? What standard? • Algorithm development responsibility?

  12. Public data products • Objectives • Data product definition • Data product development responsibility • Data access; release schedule • Data product standards/validation • Delivery mechanism • Education and public outreach • Development of display for AOVEF: what, who? • Display materials for our own use (PPT slides, etc): what, who? • Development of course-related materials (undergrad, grad): what, who? • http://www.astro.cornell.edu/academics/courses/astro620/ Data products/EPO

  13. Manpower needs • Task list and manpower requirements • Expectations for commitment at different levels • Task assignment • Reporting/tracking • Hardware needs • Disk storage location • Data transfer modes/medium • Data access policies • Raw compute power needs and resources? Locations? • Project management • Resource identification/management • Communications • Documentation development/maintenance • Conflict resolution: what if problems (such as non-delivery of promised task) arise? Resources/Management

  14. Software Issues: • Steve Torchinsky NAIC responsibilities and plans • Karen O’Neil Platforms and options • Wolfram Freudling Software plans for UltraDeep Precursor • Riccardo Giovanelli Software plans for Drift Precursor • Brian Kent Possible VO portal • Martha Haynes Software Issues from the Whitepaper

  15. Questions for NAIC • Does NAIC intend to deliver all the Level I data products as proposed in the E-ALFA whitepaper? • If not, what items will/will not NAIC provide? • What platform will form the basis of NAIC-provided monitoring and quick-look software? • How much archiving capability will NAIC provide? • Where will data be archived? • What protocol? • How will access be granted? • Will NAIC provide access tools?

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