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Low Hanging Fruit inThe New Radio Sky

orRadio Surveys and Transients

with the Allen Telescope Arrayor

The Same Road Twice

Geoffrey Bower, UC Berkeley

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ATA-42 Operational SoonATA-42 Operational Soon

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peATA FiGSS ATA FiGSS

FFive ive GGHz Hz SSky ky SSurveyurvey• 5 GHz Counterpart to Sloan Digital Sky Survey

– Overlap with NVSS, FIRST & SDSS– 104 Square degrees– Arcminute resolution

• Highest Frequency Deep, Large Radio Survey– 0.6 mJy rms– Factor of ~10 more sensitive than GB6– 2 Smaller, deeper fields

• 6 calendar months to complete with ATA-42• Extendable in area and sensitivity

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FiGSS ScienceFiGSS Science• Detect 250,000 Sources• Cross with NVSS: 1.4-5 GHz Spectral Indices

– Separate star burst galaxies from AGN– Arp 220 detectable to z=0.16 (0.3, 0.5)

• Cross with SDSS, SWIRE, COSMOS– Galaxy evolution– Obscured star-formation and AGN science– AGN activity census– Radio continuum-star formation relations

• Polarization & Rotation Measure (103 --106 rad m-2) for all objects– Identify hidden or depolarized nonthermal sources: jets, SNe remnants – Dense probe of ISM B-field

• Galactic foregrounds for CMB and EOR• Community property

– Virtual Observatory catalog• Survey sample lists• NVSS+FIRST produced more than 1000 refereed citations

– Gravitational lens source list• Flat spectrum, compact objects Geometry of the Universe (ala CLASS project)

• Transient detection

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FiGSS Layer CakeFiGSS Layer Cake

10,000 Sq. Deg. 3 mJy

100 Sq. Deg. 1 mJy

10 Sq. Deg. 0.3 mJy

Daily

Every 10 Days

Every 100 Days

Overlap with SWIRE

Overlap with SDSS/FIRST/NVSS

Overlap COSMOS

Transients & Steady Sources

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Radio Transient Source CountsRadio Transient Source Counts

FiGGS

Orphan AfterglowsRSNeTidal FlaresIDV???

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Transients Discovered in the VLA ArchivesTransients Discovered in the VLA Archives• VLA

calibration check observations

• 1983-2003• ~1000 weekly

epochs • 1.4, 5, 8.4 GHz• 40 uJy

rms/epoch• Effective

surveyed area at 600 microJy ~10 sq degrees10 Transients Discovered (□◊Δ)

Very Deep, Multi-λ Images: 2.6 uJy rms

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The Same Road Twice:The Same Road Twice:Conclusions for Legacy ScienceConclusions for Legacy Science• The radio astronomy landscape is

changing– ATA is coming soon (also LOFAR, LWA, etc.)– Complementarity & synergy of efforts is critical

• ATA has powerful survey capability– Commensal RA & SETI

• FiGSS: simultaneous survey for transient and stationary sources

• Archival data are a powerful legacy product