The µJy Sky and the Radio-FIR relation vs. z

1 EVLA VisionDecember 17, 2008

Frazer OwenNRAO

The µJy Sky and the Radio-FIR relation vs. z


Frazer OwenNRAO

Outline of Talk

1) µJy radio properties

2) Radio-FIR relation vs z

3) Implications, future directions


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• G. Morrison (UH)• M. Pannella, V. Strazzullo, W-H. Wang (NRAO)• M. Polletta (Milan)• C. Lonsdale (NRAO)• A. Baker, Matt Klimek (Rutgers)• R. Ivison, A. Biggs (ROE)• D. Shupe (Herschel)• B. Wilkes (CFA)• R. Kilgard (Wesleyan)

Short List of Collaborators


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SWIRE Deep Field: 1046+59

• Deepest existing radio survey at 20cm (rms 2.7µJy), also 50cm (10µJy), 90cm (70µJy)

• GALEX UV, ground-based optical, NIR, Spitzer IRAC, confusion-limited MIPS (24,70,160 µm),MAMBO 1.2mm, Chandra imaging, spectroscopy.

• XMM, SCUBA2, Herschel HerMES 100-500µm (1st priority) to come.


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Radio Source Photo-z’s

Pannella/Strazzullo

UgrizJHK3.6µ4.5µ


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Radio Luminosities vs. z

Majority of sources > 10^23 W/Hz, more luminous than Arp 220


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1) µJysources are

resolvedmedian size ~ 1

arcsecor ~10 kpc,unlike local ULIRGs <

100pc.


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Median Sizes from 1046+59

Large median size for sources continues down to bottom of the survey.


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20cm Log N –Log S

Log N-log S

continues flat to bottom of survey.

6 sources/sq arcmin.

EVLA: 10X deeper: natural confusion ?

Huyng et al 2005


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Radio SF or AGN ?

Both ~ galaxy size, but different relation to optical light.

M84: AGN (Mechanical Energy) M82: SF


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Relation of Radio and Optical Brightness distributions (GOODS-N)


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Radio SF vs. AGN

Condon et al 2002

Locally, AGN/SF luminosity functions cross at 10^23 W/Hz.

<10^23 SF>10^23 AGN

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EVLA VisionDecember 17, 2008

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Generic Radio/FIR Spectrum


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Radio-FIR Relation

For SF q=2.3σ(q)~0.2

Condon et al 2002

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ULIRGs (Ultraluminous Infrared Galaxies)

L_FIR > 10^12 L_sun

Local examples have radio size < 100pc

(LIRGs > 10^11 L_sun)

Arp220 L_20cm=2.3x10^23 W/HzL_FIR=1.2x10^12 L_sun

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Radio-FIR Relation vs. z from Stacking Spitzer MIPS data

• 24, 70 and 160 µm sources stacked at the radio source positions in ranges of L_20cm and z.

• 160/70 µm ratio and error calculated.• Using redshifted templates with different dust

temperatures, rest-frame: T(dust), L_FIR and q=log(L_20cm/L_FIR) are calculated.

24µ 70µ 160µ


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Best fit opt/NIRSEDs

Strazzullo et al

(2009)


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5) X-rays


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Conclusions/Speculations• Star-formation and AGN activity go together: composites• Relation of AGN activity to evolutionary sequence still

unclear but probably not related by a simple, one-time event. Too many star-forming galaxies with AGN evidence.

• Deeper Herschel, XMM, EVLA data should make the picture clearer.

• Deep EVLA imaging will probably be dominated by more extreme star-forming objects. May reach natural confusion.

• Higher resolution radio observations from EVLA, eMerlin and SKA may be most productive path for more understanding.

• Need new imaging algorithms for EVLA /eMerlin to make deep, wide-field images.

Documents

The µJy Sky and the Radio-FIR relation vs. z