AGN Content of the  Jy Population Through X-ray stacking Franz Bauer (Columbia), Glenn Morrison (Hawaii) FOR CDF/GOODS Teams

Motivation Radio traces massive SF, AGN jets Characterization of uJy population to understand evolution and interplay to other bands.  As we push deeper, we will have very limited number of diagnostics (even worse for EVLA?)  Easier to detect AGN when they dominate radio, but AGN are predicted to affect and play off of evolving galaxies of all types and could contaminate SFR estimates

X-ray Emission as SFR tracer (Lehmer et al. 2007, Persic & Rephaeli 2007)

X-ray Emission as SFR tracer (Barger, Cowie,& Wang 2007) Uh Oh?

FOCUS on DATA RICH Chandra Deep Fields Dozens of bands from NUV to 8um with extremely deep limits HST imaging Deepest X-ray coverage in entire Sky Deep MIPS 24um/70um imaging Deep 1.4GHz imaging 1000s of speczs ~100k photzs (Morrison et al. 2009)

S 1.4GHz ~20  Jy (5  ), S 24  m ~20  Jy (3  ) S 1.4GHz ~45  Jy (5  ), S 24  m ~14  Jy (3  ) S 1.4GHz vs. S 24um GOODS-N probes deep, E-CDF-S probes wide. MIPS photometry: clustering/blending leads to some overestimated MIR fluxes, while aperture photometry may lead to some underestimated MIR fluxes. Obviously confused radio/MIR sources rejected. Will soon triple GOODS-N dataset by merging with GTO MIPS data for full CDF-N field. (Morrison et al. 2009)(Miller et al. 2008)

S 1.4GHz vs. S 24um S 1.4GHz ~20  Jy (5  ), S 24  m ~20  Jy (3  )S 1.4GHz ~45  Jy (5  ), S 24  m ~14  Jy (3  ) Spec z’s for ~ 60% (only good quality z chosen if flag provided). (numerous refs) High quality phot z’s: typically  NMAD < 0.06 with ~5% outliers. (Rafferty/Xue in prep) A disproportionate % of radio sources lacking z are radio-loud and likely at z>1-2.

q 24  m vs. z SEDs locked to local q24 values and evolved using MIR spectrum convolved with MIPS 24um bandpass and radio spectral index  =-0.7. This appears to fit faint GOODS-N spike sources.

q 24  m vs. z

q cor 24  m vs. z

q cor 24 vs. L 1.4GHz Starburst? AGN? RL/RI AGN

L keV vs. L 1.4GHz X-ray/radio SFR relations X-ray AGN

L keV limits vs. L 1.4GHz X-ray/radio SFR relations X-ray AGN

L keV Stack vs. L 1.4GHz X-ray/radio SFR relations X-ray AGN X-ray Steep = SF? X-ray Flat = AGN

q cor 24 vs. L 1.4GHz Starburst? AGN! RL/RI AGN eVLA/eMerlin decide SF?

DISCUSSION/CONCLUSIONS Radio 20-40uJy population…AGN/Starburst? Likely a mix, with a significant AGN component amongst the star-forming disk. How well can we trust radio-derived SFR rates? How well can we constrain evolution? (See Ballantyne poster upstairs) Local and distant X-ray/MIR+UV correlations suggest X-ray provides a SFR baseline. What is driving the perceived large X- ray/radio dispersion? q 24 thought to be a powerful selection tool, however we may need to take conservative cuts on the radio side in order to limit AGN contamination. More investigation is needed, but appears that even a factor of ~3-10 off the most basic local template may be dominated by obscured AGN activity in radio. Furthermore, even when on template at the radio luminous end, likely to have severe AGN contamination! Several tweaks still to do with existing data…

Prospects for EVLA and future instruments to constrain AGN constrain of uJy population Spectral indices? Comparison of ~2-5” and <0.2” beams? Variability? Push comparisons to 24um to higher redshift, lower luminosities?