X-rays from the First Massive Black Holes
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X-rays from the First Massive Black HolesBrandt, Vignali, Schneider, Alexander, Anderson, Bassett, Bauer, Fan,
Garmire, Gunn, Lehmer, Lopez, Kaspi, Richards, Strateva, Strauss
www.astro.psu.edu / 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 forXMM-Newton.
X-ray Spectroscopy at z > 4
Also see Ferrero et al. (03), Grupe et al. (04)Vignali et al. (2004)
PSS 1326+0743z = 4.17XMM-Newton
PSS 0121+0347z = 4.13XMM-Newton
XMM-Newton spectroscopy possiblefor a few of the X-ray brightest quasars.
Joint fitting can place respectableaverage X-ray spectral constraints.
X-ray Spectral Comparisons at Low and High Redshifts
Vignali et al. (03)
Significant intrinsic scatterat all redshifts, but nosystematic 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 = 0.02-6.28
Partial correlation analyses indicate luminosity effectis primary.
No highly significant trendwith redshift.
New X-ray Constraints on z > 4 Radio-Loud Quasars
Bassett et al. (04)
Radio quiet
New RLQ targets
BlazarsLopez et al. (04)
12 high-redshift RLQs with flat radiospectra and moderate-to-high R.
Fill X-ray observation gapbetween RQQs and blazars.
Representative of majority of RLQs.
100% detection rate with some bright objects great for XMM-Newton.
Small-scale, jet-linked X-raycomponent (SSC) consistentat 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 > 4One “favored” model for X-ray jet emissionis IC/CMB. Need bulk relativistic velocitieson kpc scales.
If true, X-ray jets can outshine cores at z > 4.
Use Chandra’s imaging to search for suchX-ray luminous jets.
We do not detect X-ray jets in any of our12 RLQs (including objects similar to 3C 273 and PKS 0637-752).
Physical sizes < 10-15 kpc.
Such X-ray luminous jets are rare.
Perhaps synchrotron with multiple electronpopulations?
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 sourcesand candidates in centralChandra Deep Field-N
Vignali et al. (02)
Ongoing Chandra and XMM-Newton Surveys21 Ongoing Deep Surveys 18 Ongoing Wide Surveys
~ 3.5 sq. degrees in total
Lists above available from astro-ph/0403646
Constraining Lower Luminosity AGN at High Redshift
z ~ 3.0z ~ 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 supernovaremnants – no need to invoke numerous lower luminosity AGN.
Also see Moustakas & Immler (04), Wang et al. (04)
General ConclusionsAGN at z ~ 4-6 and z ~ 0-2 havereasonably similar X-ray andbroad-band spectra. No hints ofdifferent accretion/growth mechanisms.
(After controlling for luminosity effects)
Small-scale X-ray emission regionsinsensitive to strong large-scaleenvironmental 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 ProspectsImprove coverage at z = 5 - 6.5 +
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 withbest positions for ~ 20 years.
Both Chandra and XMM-Newton can gowider.
Long-Term Prospects – Proto-Quasars and Black Holes from the First Stars
1 Chandra count per 35 yr