1. National Radio Astronomy Observatory EVLA Workshop Deeper Knowledge Through Confusion Jim Condon

2. EVLA Workshop 2008 Dec 17 Outline: What can sensitive 1–10 GHz continuum surveys tell us about galaxy evolution? Current problems with continuum surveys EVLA: 5X deeper knowledge through confusion ( ~ 1000 nJy at 1.4 GHz, 600 nJy at 3 GHz, 400 nJy at 6 GHz, and 250 nJy at 10 GHz) Unique EVLA contributions as a continuum pathfinder for the SKA

3. EVLA Workshop 2008 Dec 17 FIR and radio flux densities of star- forming galaxies are correlated so the rescaled FIR (dashed curve) and radio (solid curve) LLFs of star-forming galaxies coincide; FIR and radio trace the same SFRD. solid curve: 1.4 GHz dashed curve: FIR

4. EVLA Workshop 2008 Dec 17 Luminosity Evolution Local visibility function yields counts normalized by static Euclidean counts ∆ log(L) ~ 1.2 evolution for all radio sources ~ 0.8, ∆ log(z) ~ 0.5 over wide flux range stars AGN stars

5. EVLA Workshop 2008 Dec 17 Condon (1989) and Wilner et al. (2008) models

6. EVLA Workshop 2008 Dec 17 Evolution of Star Formation: Radio View

7. EVLA Workshop 2008 Dec 17 Problems with current faint-source counts Huynh et al. (2005) P(D) 1.4 GHz

8. EVLA Workshop 2008 Dec 17

10. Deepest counts seem to disagree

11. EVLA Workshop 2008 Dec 17 Isotropy of faint NVSS sources

12. EVLA Workshop 2008 Dec 17 1.4 GHz source counts in 17 FLS fields  2 is consistent with no clustering (P > 30%) “Cosmic rms” 99%)

13. EVLA Workshop 2008 Dec 17 Faint sources and sky brightness

14. EVLA Workshop 2008 Dec 17

15. EVLA sensitivity and confusion surveys

16. EVLA Workshop 2008 Dec 17

17. EVLA confusion surveys as pathfinders for SKA

18. EVLA Workshop 2008 Dec 17 Ultimate radio survey limits confusion:  c ~.03 K (1.4 GHz) instrumental natural field of view Ω dynamic range noise 

19. EVLA Workshop 2008 Dec 17 Summary: S ~ 1  Jy surveys at 1.4 GHz can constrain the evolution of the SFRD to z ~ 1.5 Current surveys disagree below S ~ 100  Jy EVLA confusion surveys could yield source counts to S ~ 1  Jy at 1.4 GHz and measure the effective spectral index at this level. EVLA confusion surveys will be the deepest pathfinders for SKA continuum surveys, and they will approach the natural confusion limit.

20. EVLA Workshop 2008 Dec 17

21. X-band surveys Small numbers of sources Spectral-index distributions differ?

22. EVLA Workshop 2008 Dec 17 Isotropy of strong sources

23. EVLA Workshop 2008 Dec 17 Detecting distant sources and characterizing source populations

24. EVLA Workshop 2008 Dec 17 The recent SFRD is proportional to ∫u m d log(L) = 1.5  10 19 W Hz -1 Mpc -3 at 1.4 GHz M82 Arp 220 Power-density functions Vir A

25. EVLA Workshop 2008 Dec 17

26. The 1.4 GHz sky at 5 arcsec resolution, 23 µJy/beam = 0.6 K rms noise ~1/2 AGN ~1/2 star- forming galaxies part of the Spitzer FLS / VLA survey