X-rays from the First Massive Black Holes Brandt, Vignali, Schneider, Alexander, Anderson, Bassett, Bauer, Fan, Garmire, Gunn, Lehmer, Lopez, Kaspi, Richards, Strateva, Strauss / users / niel / papers / highz-xray-detected.dat Chandra 4-10 ks snapshots (>100) z > 4.8 SDSS, Opt. bright, RLQs, Exotic High detection fraction ROSAT, Chandra, XMM-Newton archives Additional z > 4 detections Supporting samples at z = 0-4 Deep X-ray surveys Are early black holes feeding and growing in the same way as local ones?

X-ray Versus Optical Fluxes X-ray and optical fluxes correlated. Fluxes generally low; X-ray spectroscopy challenging even for XMM-Newton.

X-ray Spectroscopy at z > 4 Also see Ferrero et al. (03), Grupe et al. (04)Vignali et al. (2004) PSS z = 4.17 XMM-Newton PSS z = 4.13 XMM-Newton XMM-Newton spectroscopy possible for a few of the X-ray brightest quasars. Joint fitting can place respectable average X-ray spectral constraints.

X-ray Spectral Comparisons at Low and High Redshifts Vignali et al. (03) Significant intrinsic scatter at all redshifts, but no systematic trend. Inner-disk coronae stable. No X-ray reflection “humps” detected. No X-ray absorption detected.

X-ray Contribution to Spectral Energy Distribution Also see Vignali, Brandt, & Schneider (2003) Combine high-redshift sample with well-defined, lower-redshift samples to constrain X-ray evolution. Want broad lum. and z coverage to break degeneracies High-detection fraction (pattern censoring issues) Reliable separation of RQQ and RLQ Good BAL removal / control New sample of ~ 152 SDSS and PSS quasars spanning z = Partial correlation analyses indicate luminosity effect is primary. No highly significant trend with redshift.

New X-ray Constraints on z > 4 Radio-Loud Quasars Bassett et al. (04) Radio quiet New RLQ targets Blazars Lopez et al. (04) 12 high-redshift RLQs with flat radio spectra and moderate-to-high R. Fill X-ray observation gap between RQQs and blazars. Representative of majority of RLQs. 100% detection rate with some bright objects great for XMM-Newton. Small-scale, jet-linked X-ray component (SSC) consistent at z > 4 and z ~ 0. Degree of X-ray enhancement vs. RQQs X-ray spectral shape Suggestive evidence for X-ray absorption.

Rarity of X-ray Luminous Jets at z > 4 One “favored” model for X-ray jet emission is IC/CMB. Need bulk relativistic velocities on kpc scales. If true, X-ray jets can outshine cores at z > 4. Use Chandra’s imaging to search for such X-ray luminous jets. We do not detect X-ray jets in any of our 12 RLQs (including objects similar to 3C 273 and PKS ). Physical sizes < kpc. Such X-ray luminous jets are rare. Perhaps synchrotron with multiple electron populations? Following Rees & Setti (1968) etc.

X-ray Survey Constraints on z > 4 AGN Probe moderate-luminosity, typical AGN at z > 4 Minimize absorption bias (rest-frame 2-40 keV) Find or constrain sky density exploiting Lyman break. Alexander et al. (01), Barger et al. (03), Cristiani et al. (04), Koekemoer et al. (04) Constraints on reionization. High-redshift sources and candidates in central Chandra Deep Field-N Vignali et al. (02)

Ongoing Chandra and XMM-Newton Surveys 21 Ongoing Deep Surveys18 Ongoing Wide Surveys ~ 3.5 sq. degrees in total Lists above available from astro-ph/

Constraining Lower Luminosity AGN at High Redshift z ~ 3.0 z ~ 3.8 Lehmer et al. (04) X-ray Stacking of Large Lyman Break Galaxy Samples from GOODS 468 U-dropouts from GOODS-N Effective exposure = 0.8 Gs ~ 25 yr 338 B-dropouts from GOODS-N, S Effective exposure = 0.4 Gs ~ 13 yr Also tight constraints on V, i dropouts at z ~ 5, 6 Observed X-ray emission plausibly from X-ray binaries and supernova remnants – no need to invoke numerous lower luminosity AGN. Also see Moustakas & Immler (04), Wang et al. (04)

General Conclusions AGN at z ~ 4-6 and z ~ 0-2 have reasonably similar X-ray and broad-band spectra. No hints of different accretion/growth mechanisms. (After controlling for luminosity effects) Small-scale X-ray emission regions insensitive to strong large-scale environmental differences from z ~ 0-6. X-ray emission universal. X-ray surveys giving significant demographic constraints on mod.-lum. AGN at highest redshifts.

Some Future Prospects Improve coverage at z = Other selection methods – minimize bias IR, submm, mm Minority populations Weak-line quasars, BALQSOs, RLQs Better X-ray spectral and variability studies Chandra can go significantly deeper with best positions for ~ 20 years. Both Chandra and XMM-Newton can go wider.

Long-Term Prospects – Proto-Quasars and Black Holes from the First Stars 1 Chandra count per 35 yr