Black Holes in the Deepest Extragalactic X-ray Surveys Chandra X-ray Observatory X-ray Multi-Mirror Mission-Newton Angular res. and positions improved by factor ~ 10. 50-250 times sensitivity of previous missions. Photon collection improved by factor ~ 10. Both operating well and can likely continue for ~ 5-10 more years.

X-ray Imaging Optics

X-ray CCD Detectors XMM-Newton EPIC Chandra ACIS

The Cosmic X-ray Background

X-rays from Active Galaxies

Nuclear Obscuration in Active Galaxies Obscuring “Torus” Cut-Through View

Three Important Reasons to Survey in X-rays 1. X-ray emission universal property of accreting supermassive black holes 2. Penetrating; reduced absorption bias 3. Low dilution by host-galaxy light X-ray emission can penetrate and measure large amounts of absorbing material. Majority of active galaxies are absorbed. Absorption bias drops going to high redshift.

Penetrating Power of X-rays

Many Complementary X-ray Surveys Ongoing Blue = Chandra Green = XMM-Newton Red = ROSAT About 35 ongoing surveys with Chandra and XMM-Newton. Usually performed in regions with strong multiwavelength data and / or notable objects. Together the surveys cover a broad part of the sensitivity vs. solid-angle “discovery space”. I will focus on results from the deepest X-ray surveys. Equally important results from wider X-ray surveys!

Supporting Multiwavelength Data: HST

Supporting Multiwavelength Data: Spitzer

Supporting Multiwavelength Data: Submillimeter James Clerk Maxwell Telescope Mauna Kea, Hawaii

The Deepest X-ray Surveys to Date The Chandra Deep Field-North (CDF-N) The CDF-S and Extended CDF-S 250 ks to 2 Ms coverage 1125 arcmin2 (~ 150% Moon) ~ 990 point sources

Matching of X-ray and Optical Sources

Optical Spectroscopic Follow-Up Observations to Get Redshifts Keck Observatory Very Large Telescope

Follow-Up Challenges and Results X-ray Number Counts for Chandra Deep Fields 50-70% spectroscopic completeness overall. Good completeness to I ~ 23-24. Hundreds of very faint sources, often with weak-to-moderate line emission. Further deep spectroscopy needed to identify these. Likely are obscured AGN at z ~ 1.5-6. More than 70% of sources are z ~ 0.1-5 AGN. AGN source density ~ 7200 deg-2. Also many starburst and normal galaxies. Rapidly rising population to faintest X-ray fluxes.

Highlights on Some Key Topics Number-density and spectral evolution of AGN. AGN content of distant submillimeter galaxies. Other great topics: Host galaxies, AGN clustering, variability, absorption, starburst & normal galaxies, clusters & groups.

Evolution of Luminous Quasars

Luminosity Dependent AGN Evolution Number-Density Changes for AGN of Different Luminosities Probe evolution of moderate luminosity AGN. More numerous! Lower luminosity AGN peaked later. Called “anti-hierarchical growth” or “cosmic downsizing.” Basic result appears robust to incompleteness, but details still uncertain. More “frugal” X-ray universe than some expected before Chandra and XMM-Newton. X-ray background not dominated by many obscured quasars. AGN make ~ 5-10% of the power in the Universe since the formation of galaxies (not ~ 50%).

Black-Hole Accretion Versus Cosmic Star Formation SFR density Scaled SMBH accretion-rate density Accretion-rate density and cosmic star-formation rate density similar to first order.

Luminosity Dependence and Evolution of AGN Spectra X-ray strong BQS BQS SDSS z > 4 snapshots E-CDF-S SDSS Seyfert 1s X-ray weak E-CDF-S BQS SDSS E-CDF-S SDSS z > 4 snapshots Luminosity dependence of X-ray vs. total power. X-ray fraction declines with luminosity. Not understood. No detectable redshift dependence. X-ray-to-optical flux ratios of AGN change by < 30% from z = 0-6. Despite large number-density changes, individual AGN “unit” is remarkably stable over ~ all of cosmic history.

AGN Content of Distant Submillimeter Galaxies Submm from dust-shrouded starbursts forming stars at ~ 1000 solar masses / year. About 1000 times more common at z ~ 2 as today. Likely seeing the epoch of spheroid formation in massive galaxies at z ~ 1.5-4.0. James Clerk Maxwell Telescope Mauna Kea, Hawaii Submm sources in 2 Ms Chandra Deep Field-North Green = X-ray detected submm sources (17/20) Yellow = X-ray undetected submm sources (3/20) Can we see the black hole growing inside the forming spheroid? About 85% of submm galaxies with precise positions have detections in Chandra Deep Field-North. Detection fraction much higher than for any other coeval galaxy population. Most appear to contain obscured AGN. Seeing simultaneous growth of black hole and spheroid in “pre-quasar” phase? 0.5-8 keV image

Pushing Back the “Edge” of the X-ray Universe Chandra has not yet reached its natural limits. Can go much deeper while remaining confusion free and largely photon limited. Heavily obscured AGN that are currently missed Better photon statistics for better X-ray spectra and variability Normal and starburst galaxies

Prospects for the Long Term NuSTAR eROSITA International X-ray Observatory