black holes in the deepest extragalactic x-ray surveys

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

Chandra ACIS

XMM-Newton EPIC

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

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.

1. X-ray emission universal property of accreting supermassive black holes

Penetrating Power of X-rays

Many Complementary X-ray Surveys Ongoing

About 35 ongoing surveys with Chandra and XMM-Newton.

Usually performed in regionswith 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 fromwider X-ray surveys!

Blue = ChandraGreen = XMM-NewtonRed = ROSAT

Supporting Multiwavelength Data: HST

Supporting Multiwavelength Data: Spitzer

Supporting Multiwavelength Data: Submillimeter

James Clerk Maxwell TelescopeMauna Kea, Hawaii

The Deepest X-ray Surveys to DateThe 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

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.

X-ray Number Counts for Chandra Deep Fields

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 EvolutionProbe evolution of moderateluminosity AGN. More numerous!

Lower luminosity AGN peakedlater. Called “anti-hierarchical growth” or “cosmic downsizing.”

Basic result appears robust to incompleteness, but detailsstill uncertain.

More “frugal” X-ray universethan some expected beforeChandra and XMM-Newton.

X-ray background not dominated by many obscured quasars.

AGN make ~ 5-10% of the powerin the Universe since the formationof galaxies (not ~ 50%).

Number-Density Changes for AGN of Different Luminosities

Black-Hole Accretion Versus Cosmic Star Formation

SFR density

Scaled SMBHaccretion-rate density

Accretion-rate density and cosmic star-formation rate density similar to first order.

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.

X-ray strong

X-ray weak

SDSSz > 4 snapshots

BQS E-CDF-SSDSS

E-CDF-SSDSS

BQS

Luminosity Dependence and Evolution of AGN Spectra

z > 4 snapshots

SDSS

E-CDF-S

BQS

Seyfert 1s

AGN Content of Distant Submillimeter Galaxies

James Clerk Maxwell TelescopeMauna Kea, Hawaii

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.

Can we see the black hole growing inside the forming spheroid?

About 85% of submm galaxies withprecise 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?

Submm sources in 2 Ms Chandra Deep Field-NorthGreen = X-ray detected submm sources (17/20)

Yellow = X-ray undetected submm sources (3/20)

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