Arecibo Frontiers – 12 Sep 2007 1 Beyond the Frontiers: The Road From Arecibo to The Radio...

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1 Arecibo Frontiers – 12 Sep 2007 Beyond the Frontiers: The Road From Arecibo to The Radio Synoptic Survey Telescope (RSST) Steven T. Myers National Radio Astronomy Observatory Socorro, NM

Transcript of Arecibo Frontiers – 12 Sep 2007 1 Beyond the Frontiers: The Road From Arecibo to The Radio...

Page 1: Arecibo Frontiers – 12 Sep 2007 1 Beyond the Frontiers: The Road From Arecibo to The Radio Synoptic Survey Telescope (RSST) Steven T. Myers National Radio.

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Beyond the Frontiers: The Road From Arecibo to

The Radio Synoptic Survey Telescope(RSST)

Steven T. Myers

National Radio Astronomy Observatory

Socorro, NM

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What is the RSST?

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The Radio Synoptic Survey Telescope

• The RSST concept is for a “SKA-mid” facility– see “Chicago 3” meeting later this week

• Primary Science Goals– Cosmological HI Large Deep Survey (CHILDS)

• billion galaxies to z~1.5 (and beyond)• redshift survey• galaxy evolution

– Deep Continuum Survey (DeCoS)• radio photometric and polarimetric survey

– Transient Monitoring Survey (TraMS)• commensal with other RSST surveys

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What is the RSST?

• Radio?– core frequency range 0.4-1.4 GHz (z<2.5)

• A Square Kilometer Array– square kilometer of something (effective area?)

– high gain/low noise A/Tsys ≈ 2×104 m2 K-1

• don’t throw away all that collecting area!

– wide field-of-view, target 1 square degree– “Areal Product” A ≈ 106 m2 deg2 (at 1.4 GHz)

• A Survey Telescope– cover large areas of sky 104 deg2 = ¼ sky

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The Synoptic Part

• Revisit the sky regularly– if you want to cover 104 deg2 with 1deg2 FOV– can do so in 1 day with 2-8s per point– different parts of survey can have different

depths (and thus cadences)

• What cadence? Depends on the science– many short visits or fewer longer ones?– looking for individual “bursts” or “pulses”?– looking for groups or trains of pulses?– classical variability curves (e.g. microlensing)?

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Arecibo asa RSST Precursor

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Numerology

• What about that A thing?– Arecibo 90 m2 deg2 (single beam at 1.4 GHz)– vs. EVLA 2300 m2 deg2 (25x better but *)

• But, if A~naD2 and ~nb(/D)2

– A ~ nanb

– all single dishes the same for single feed– AO single beam 27x worse than EVLA

• Arecibo must multibeam, the more the better

– bigger array (LNSD) or camera (Megapix) wins!– SKA ~ 104 beams × elements = 10 Megapix

* EVLA has limited frequency coverage below 1GHz, and “starts” in 2010

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Perspective: Figures of Merit at 1.4GHz

• Areal Product– SKA: A ≈ 106 m2 deg2

• Area/Tsys– SKA: A/Tsys ≈ 2×104 m2 K-1

• Survey Speed– SKA: (A/Tsys)2 ≈ 3×1017 deg2 m4 K-2 Hz-1

– product of A and A/T and T

• Upshot for surveys:– AO and EVLA equivalent for 7 beams (ALFA)

• 0.002% of SKA

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Focus for Arecibo? My take …

• Must have large multibeam “camera”– ALFA 7x, ALFA++ 40, can we get 100?

• Should focus on interesting targets– make every beam count!– smaller surveys, like Virgo or galactic regions– hit targets matched to camera footprint– can be commensal with other observations

• Sensitivity = Thresholding– Arecibo has 0.03 square km eff. area (11 K/Jy)– can go deeply if interesting stuff in beam

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What Arecibo Provides

• Highest Instantaneous Sensitivity per beam– allows detection of faint phenomena– sets threshold for transient detections– sets depth of “survey” in pointing: d ~ A½

• Arecibo depth 17% of SKA! Not too shabby!

• Some key thresholds– see Cordes et al. SKA ScienceBook paper

• mostly continuum phenomena (possibly dispersed)• 10Jy-1Jy (ALFA 3Jy SEFD ~ 0.17 mJy in 1s)

• e.g. Crab giant pulses d ~ 1.6Mpc (A/AAO)½

– also HI threshold (see this afternoon session)

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Summary: Arecibo as a Precursor

• Arecibo can be profitably used to pioneer SKA science– but need to target key projects and objects

• Science it would be good to know…– giant pulsar pulses in nearby galaxies– radio bursts from extrasolar planets– HI galaxy mass function and bias– add to list from other talks at this meeting!

• These provide critical informed input to design of next generation projects

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RSST Roadmap

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What really needs to happen

• Need to write a White Paper for DR– assemble small “blue team” to write the case– need punchy science case– remaining technical development?– need “Phase A” level costing– put in front of “red team” next year– present to Decadal Review

• How does AO fit into the next decade?– Arecibo “White Paper” for DR?– need science output throughout decade

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For more information…

• RSST White Paper (draft)– on this conference website:

http://www.naic.edu/~astro/frontiers/RSST-Whitepaper-20070910.txt

• SKA Info– http://www.skatelescope.org– particularly see the “Science Book”

• “The Dynamic Radio Sky” by Cordes, Lazio & McLaughlin

• “Galaxy Evolution, Cosmology, and Dark Energy with the SKA” by Rawlings et al.