x-ray astronomy # 12belinda wilkes, 29 nov 2007 8.971: x-ray astronomy lecture 12 super-massive...

X-ray Astronomy # 12 Belinda Wilkes, 29 Nov 2007

8.971: X-ray Astronomy

Lecture 12

Super-Massive Black Holes, Jets, AGN, Quasars, Blazars

Belinda Wilkes

Chandra X-ray Center

Smithsonian Astrophysical Observatory


Super-Massive Black Holes (SMBH)• Active Galactic Nuclei (AGN):

– Galaxy containing a SMBH (log Mo=6-10) at its core– Strong, broad (~103 kms-1), high-ionization emission

lines – Strong, narrow (~100 kms-1), low-ionization lines

• Many observational types, related via Unification models:– Quasars/Quasi-Stellar Objects (QSOs)– Seyfert galaxies (types: 1-2)

• Type 1: broad and narrow emission lines• Type 2: narrow emission lines only

– Broad Line Radio Galaxies– Narrow Line Radio Galaxies


X-rays and Active Galaxies• AGN are multi-wavelength emitters: radio-X-ray

(and γ-ray)• Strong X-ray sources

– X-ray surveys mostly see AGN so are a good way to find them

– Provide information on nuclear regions– Major advances with current X-ray satellites

• Chandra + XMM-Newton’s main roles:– Finding new SMBHs: Surveys– High signal-to-noise CCD spectroscopy– High Resolution Spectroscopy– X-ray jets


Unification


The Nuclear Regions of an AGN

• View of Active Galaxy (AGN) depends on inclination

• Optical/UV light: obscured when edge-on

• Traditional surveys: optical/UV, soft X-ray

• Hard X-ray/IR/radio surveys see all

Nuclear region of an AGN/Quasar


Unification Model: nuclear regionsX-ray source

Accretion Disk: OUV +soft X-ray

emission

Dusty material: near+mid IR

emission

X-ray reflection off cold/warm material

Scattered, polarized light

BROAD LINE REGION

NARROW LINE REGION

Type 1

Type 2


Spectral Energy Distributions of Active Galaxies

Face-on View

Elvis et al. 1994Radio X-ray

Edge-on View

EB-V=0.6


Emission Mechanisms

• Synchrotron• Synchrotron + thermal

• Thermal: gas in accretion disk

• Synchrotron self-Compton from radio

• Synchrotron (beamed)

• Synchrotron• Thermal: dust with wide

temperature range (~50-1000K)

• Thermal: gas in accretion disk (AD)

• Thermal Comptonisation of UV

Radio-quiet Radio-loud

Radio

Infrared

Optical/UV+soft X-ray

Hard X-ray

γ-ray


Complex Unification!

• X-ray surveys generally find:– Type 1 AGN - unobscured– Type 2 AGN – obscured– Consistent with simple

Unification models

• But MANY exceptions:– Broad Absorption Line (BAL)– Red AGN– Intermediate types (1.2-1.9)– XBONGs

• Disk-wind models (Konigl & Kartje 1994)

Elvis

Urry & Padovani


Surveys


To View the Population• Optical and soft X-rays miss edge-on/obscured AGN and

quasars• An unbiased view of the population

– X-ray surveys: Chandra, XMM-Newton– Infrared (IR) Surveys: 2MASS, Spitzer– Γ-ray: Integral– Low-frequency Radio: 3CR

• Many ongoing, deeper, multi-wavelength surveys, cover full range of possibly SEDs

• Can Unification explain the many varieties of AGN?

20 years ago

Now


X-ray Surveys• Strategy: layered surveys

– Deep, narrow: all populations, small number sources, cosmic variance:

• Chandra Deep Field North: .08 deg2 (1 ACIS-I field); 2 Msecs

• Chandra Deep Field South: .08 deg2, 2 Msecs; + 4 flanking fields, 250 ksecs

– Medium deep, wider: larger samples, miss faintest AGN, less cosmic variance:

• SWIRE: 0.6 deg2, 70 ksecs• COSMOS 0.6 deg2, 200 ksec• Groth Strip: 0.25 deg2, 200 ksecs, 0.25 deg2, 800 ksec


X-ray Surveys (cont)• Layered Surveys (cont)

– Shallow and Wide: very large samples, only brightest sources, little cosmic variance

• Bootes: 9 deg2, 5-10 ksecs

• Multi-wavelength approach, finds more AGN types:– optical (ground based, HST)– Near-IR (ground-based)– Far-IR (Spitzer)– Radio (ground-based)


SWIRE/Chandra Survey

• 0.6 deg2 contiguous, 70 ksecs

• Lockman Hole region of SWIRE

• Centered on Deepest VLA image

• X-ray flux limit: 2x10-16 erg cm-2 s-1

• Depth: distinction between AGN and starbursts (undetected)

(w/Lonsdale, Kilgard, Polletta, Smith, Owen, et al.)


775 unique X-ray sources to a limiting flux of 2x10-16 erg cm-2 s-1

765 with secure IR counterparts and 626 secure optical counterparts

>160 radio counterparts (analysis on-going)

75 spec z (so far)

49 X-ray sources coincident with optically extended galaxies

2 extended X-ray sources (clusters)

Statistical Results

SWIRE/Chandra Survey


SWIRE X-ray Sample

• Standard R vs X plot• Blue lines indicate

AGN region (not well-defined)

• Radio sources all over

• Extended sources in low L AGN region

R

X-ray


Current X-ray and IR Surveys→ Broader range of SEDs

• Einstein-era: optically/radio-selected, blue bias (Elvis et al. 1994)

• HEAO: hard X-ray, reduces blue bias (Kuraskiewicz et al. 2003)

• 2MASS: J-K>2, red AGN, little/no blue bump (Kuraskiewicz et al. 2007, Fig 4b)

IR Optical


Obscured AGNlog NH ~ 21-24

• Potential:– Numbers: geometry of central regions– Properties: information on obscuring material

• No single population (Alexander et al. 2003,

Rosati et al. 2002): – Type 2 AGN/QSOs (Norman et al 2002, Kim et al. 2006)

– Compton-thick AGN (Polletta et al. 2006)

– XBONGS (Fiore et al. 2000, Kim et al. 2006)

– Obscured type 1 AGN (Wilkes et al 2002)

– Optically Highly Polarized Type 1 AGN (Smith et al. 2002)


Compton-thick AGN

• 5 hard X-ray selected (2 at z>2)

• 120 red, AGN-dominated, IR-selected: power-law SED, αIR>1.0

• >25 Compton-thick AGN deg-2

• 40% optical O/IR AGN 60% host galaxy dominates

• 30% X-ray detected to F(.3-8)~10-15 erg cm-2 s-1

(Polletta et al. 2006)


SWIRE: X-ray Compton-Thick QSO

• SW 104409, z=2.54• X-ray HR~0.85, 11 cnts• NLSy1 optical spectrum• SED:

– Obscured QSO, AV=4

– 0.6% QSO type 1 (scattered light)

(Polletta et al. 2006)

X-ray Optical/IR


• 44 2MASS Red (J-K>2) AGN w/Chandra

• 21 spectral fits:– Log NH~22

– PL slope flatter for weaker X-rays

Chandra data: Wilkes et al., in prep

Red AGN: Hard X-ray Spectra


XMM-Newton Observations

• 8 X-ray-bright, 2MASS AGN:– Range of optical types and X-ray hardness ratio

• Variety of results:– Complexity in type 1 and 1.5s– Type 2 consistent with Unification– Variation in 3 (1 of each type)– No systematic error in Chandra data– BUT low S/N data are misleading

• Harder X-ray: due to NH + reflection

(Wilkes, Pounds et al. 2005, 2007)


Complex Red Quasar: 2M1049+5837

• Optical Type: 1.8• X-ray hard (HR=0.6)• 2 scattering regions:

– Blue: thin, small dust grains

– Red: dusty region, red due to obscuration

– Starlight dilution

• HST ACS imaging: – Blue fan (3.5”– Red fringe (polar, 2”)

Schmidt et al 2007

Blue Red


XMM-Newton Data

• Unusually hard 2-10keV spectrum, HR~0.6

• Requires:– Compton-thick PL– Unabsorbed Cold

Reflection – Soft excess: warm

ionized region – Scattered power law

~1.7%

Wilkes, Pounds, Schmidt, in prep.


Over-the-Top View

Courtesy Charlotte Garcia


Towards the Full Population

• We are finding a lot of new varieties of AGN

• Collecting so much data on so many sources takes a while

• We still do not have a census

• But we will!


GRATING SPECTRA


NGC3783• Seyfert 1, Redshift, z=0.009760, V=13.5• 900 ksec HETG observation (Cycle 2 LP)• Extremely rich emission and absorption

spectrum• 9 papers modeling physical and dynamical

conditions and variability• 3 or 4 co-spatial, out-flowing absorbers, range

of ionization and velocity (Netzer et al 2003, Krongold et al 2003)

• Not many AGN sufficiently bright


JETS


Actual Chandra First Light

• Point Source to focus: Quasar PKS0637-75, z=0.5

• X-ray Jet visible: 10” long, 400,000 lyrs

• Birth of a new research topic!


M87 Jet in Radio and X-rays

Radio

X-rayDouble-lobed radio source with one-sided relativistic jet


X-ray/Radio Jets in QuasarsM87 jet in X-ray, radio and optical


X-ray Emission Mechanisms

• Radio: Synchrotron emission• Radio/X-ray ratio often

constant along 10-100 kpc jet length

• X-ray: Inverse-Compton (IC) Scattering

• IC Seed photons: – Self, i.e. synchrotron photons– Cosmic Microwave Background

(CMB)

• Ongoing discussion!


Double QuasarChandra: spatial + spectral

resolution


NGC 6240: Galaxy with Double X-ray Core

Starburst

LINER z=0.0245


NGC 6240 Spectra

NGC 6240: X-ray Spectrum

Fe Kα (6.4keV)

2 2


NGC 6240NGC 6240 Movie Movie


X-ray Studies of AGN• Full View of Population:

– from surveys, need Chandra - coming soon!

• Evolution of Population (not today): – from surveys, need Chandra - very close

• Low-resolution spectral studies: – progress made, XMM-Newton best instrument– need Con-X to push to high-redshift

• High-resolution spectral studies:– New capability, progress but is hard

• Jets: – New field, lots of progress, Chandra is primary instrument

x-ray astronomy # 12belinda wilkes, 29 nov 2007 8.971: x-ray astronomy lecture 12 super-massive...

Documents

xray astronomy lecture

population xray surveys

ray slide

unification slide

active galaxies agn

agn view of active galaxy

agnquasar slide

agn unobscured type