Don Backer - introduction and welcome Brief description of ATA status, introduction to Radio Sky Surveys project, to take place from 2010-2017. Expand ATA to 256 or 350 antennas. Conduct 5 years of sky surveys. Seeking continued support of NSF, PGAFF, and USAF. Geoff Bower - agenda RSS goals: o Conduct term-limited surveys (transients, extragalactic HI, pulsar timing, Galactic spectroscopy, commensal SETI where feasible) o Build ATA out to 256 antennas o Public / private partnership in funding - $10m ops + $10m science, both spread over 5 years + $40m construction o Community projects o Radio telescope network - EVLA, VLBA, GBT, AO, ASKAP, etc.; multiwavelength and international partners o Build survey science community o Develop large-N capability -> SKA (calibration and imaging, station analog, data management, operations) Construction can take place without much more tech development and without major interruptions to observing. Bryan Gaensler: Does this include software development? Geoff: It ought to. Feb 15 is deadline for white papers on science topics. 7 pages plus 1 cover page, web links permitted. White papers should focus on the central questions (up to four) that are being addressed in each area of the Decadal Survey. Notice of intent due Jan 14 - this includes a list of participants. Jack Welch - intro to the ATA Geoff - imaging transients. FiGSS table (showing cadences, sensitivities, etc.) is illustrative of the level of detail required for the white paper (cf. LSST - they have all this detail worked out). Don: Remember that we can do things commensally too. Geoff: For example, run the Fly's Eye fast autocorrelator to look for bursts while all the antennas are pointed in the same direction doing something else (e.g. HI observing). Fast dump time correlator, and hybrid imaging with sub-arrays. Aiming for dump times of 10 ms for fast dump time correlator, although this might lead to data rate problems. Challenges: o Algorithms for hybrid mode o Real-time processing / thinking telescope: - pipeline calibration, imaging, source detection - classification - notification - response o Data archiving Peter: Should we emphasise the complementarity of LSST and ATA to the decadal panel? Geoff: Yes. The ATA, PanSTARRS and LSST are well-matched. Fields of view are similar. The SDSS is a paradigm that we want to follow. Bryan: ASKAP can do similar things up to dec = +50. We have to come up with a process by which we divide up the sky. ATA might give better localisation at 5 GHz, for example. Geoff: ATA has broader frequency coverage. Leo - RSST and extragalactic HI. We need to make a survey of molecular gas in order to understand the connection between atomic and molecular gas. Locally we know that the ratio of the two depends on hydrostatic pressure, but we need more detail to understand the star formation history of the Universe. A start has been made by ALFALFA at Arecibo, but the ATA-256 will have more than twice the sensitivity of Arecibo, and be better than the eVLA too. In terms of speed, it's nearly 6 times faster than Arecibo and twice as fast as eVLA. We'd like to do a survey that's complete in volume to measure galactic and intergalactic gas. Can observe all galaxies with MW HI mass (> 10^9.6 Msun) out to redshift of 0.08. Out to z=0.16, we'll detect the most massive galaxies (HI mass > 10^10.2). Other interesting surveys would be high redshift CO (J=1-0) at 25 GHz (z > 3.6) - this requires modification to the ATA to reach high frequencies. Perhaps we can do integrated baryon acoustic oscillations, look for dark galaxies, and other extragalactic topics. Jack - Galactic spectroscopy. Ed Churchwell: Need to do chemistry of infrared dark clouds, extended green objects, and look at radio recombination lines in the 1 - 12 GHz range in HII region bubbles. The ATA would allow enough time to do follow-up. ATA-256 would be best matched to higher-resolution work such as that on extended green objects, to find maser spots. Geoff: Carl Heiles has sketched out a survey of several hundred square degrees to map magnetic field in large structures in the Galaxy. Bryan has been looking at polarisation data. Don: New frontiers in "pulsarology". Radio telescopes might be able to detect gravitational waves from merging SMBHs (via pulsar timing) before LISA or LIGO. Can also test general relativity in pulsars. And can explore extreme states of matter such as the interior of the neutron star. Several features of ATA make it ideal for these studies: broadband sensitivity (3 or 4 frequencies are necessary to remove effects of interstellar weather), collecting area, and commensal science can go on at the same time. Need to get down on paper what's required on the digital signal processing side to make this happen. Geographic location is a minus. Fred Lo: How much time would this take though? You need a panel to choose which science case is most convincing. What can uniquely be done in the radio? Geoff: This should proceed in a similar way to the ALFA consortia. Different teams propose for their science. Fred: The difference is that Arecibo is already there whereas you're asking for money to build the telescope. LIGO spent $300m - why don't we say that we /will/ detect gravitational waves. Jim Cordes: We have to be honest when talking among ourselves that this is extremely difficult. Fred: We're on the same footing as LIGO and LISA. Crystal: EVLA phase 2 failed on the basis of a laundry list. Jill Tarter: The funds to build the ATA to date have come to a large extent on the basis of doing SETI. General philosophy has been to assign 2 tunings to radio astronomy and 2 to SETI. SETI is compatible for HI, but not so much with transient surveys such as FiGSS because we want to look at the same field for a longer period of time. Moving towards a software defined radio telescope based on an open-source model. Can also use active nulling - put a second beam on another star, and then if we see the same signal in both beams we know it's interference. Started doing commensal observing - 50 stars in the direction of M 81. Almost at the point where we can really start doing SETI surveys. 6 months of observing, 5 - 6 times a day, to do Galactic plane waterhole survey. ATA-350 is not as much of an issue in terms of sensitivity for SETI searches as it is for the ability to do better nulling. Geoff: Space Situational Awareness may take up to 30% of the time on ATA. This would come with a stable stream of funding. Jim: When will we know if this partnership is going ahead? Don: In time for the full NSF proposal. Jim: You want to be selective for the Decadal panel but still get broad support for the community. Bryan: We can do the NVSS at a range of frequencies. Don: We've costed the construction in some detail for the Allen Foundation, so we can be quite convincing even to an external auditor. Jim: The ATA is well-positioned as an SKA precursor. Surveys, particularly commensal, is something that the ATA does well. It's also being done now at Arecibo too. The ATA can address issues regarding large N, calibration and processing, RFI mitigation, wide field of view, commensal observing - operational pathfinding for SKA - as well as science pathfinding to figure out what science the SKA should do. Jim: $60m is below the $100m MREFC threshold. Jill: We have to show that large N (where N=256) is feasible in advance of SKA. Geoff: Action items: January 14 - notice of interest has to be submitted - if you want to be attached let us know. If you want to be part of a science team writing a white paper, we have identified the internal leads. Now let's assign external leads. So there are 7 areas - we're looking at writing 7 white papers.