Transcript PowerPoint Presentation - High Energy Astrophysics Division

8.971: X-ray Astronomy
Lecture 12
Super-Massive Black Holes, Jets, AGN,
Quasars, Blazars
Belinda Wilkes
Chandra X-ray Center
Smithsonian Astrophysical Observatory
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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
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Belinda Wilkes, 29 Nov 2007
Unification
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Belinda Wilkes, 29 Nov 2007
The Nuclear Regions of an AGN
Nuclear region of an AGN/Quasar
• View of Active Galaxy
(AGN) depends on
inclination
• Optical/UV light:
obscured when edgeon
• Traditional surveys:
optical/UV, soft X-ray
• Hard X-ray/IR/radio
surveys see all
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
Unification Model: nuclear regions
X-ray source
Type 1
BROAD LINE
REGION
NARROW
LINE
REGION
Accretion Disk:
OUV +soft X-ray
emission
Type 2
Scattered,
polarized light
Dusty material:
near+mid IR
emission
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X-ray reflection off
cold/warm material
Belinda Wilkes, 29 Nov 2007
Spectral Energy Distributions of
Active Galaxies
Face-on View
Edge-on
View
EB-V=0.6
Radio
Elvis et al. 1994
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X-ray
Belinda Wilkes, 29 Nov 2007
Emission Mechanisms
Radio-quiet
Radio-loud
• Synchrotron
• Synchrotron
• Synchrotron + thermal
•
Thermal:
dust
with
wide
Infrared
temperature range
(~50-1000K)
• Thermal: gas in
Optical/UV • Thermal: gas in
accretion disk (AD)
accretion disk
+soft X-ray
Radio
Hard X-ray • Thermal
Comptonisation of UV
γ-ray
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• Synchrotron selfCompton from radio
• Synchrotron (beamed)
Belinda Wilkes, 29 Nov 2007
Complex Unification!
Urry & Padovani
• X-ray surveys generally
find:
Elvis
– 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)
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Belinda Wilkes, 29 Nov 2007
Surveys
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Belinda Wilkes, 29 Nov 2007
To View the Population
• Optical and soft X-rays miss edge-on/obscured AGN and
20 years ago
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
Now
range of possibly SEDs
• Can Unification explain the many varieties of AGN?
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Belinda Wilkes, 29 Nov 2007
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 Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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)
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Belinda Wilkes, 29 Nov 2007
SWIRE/Chandra Survey
(w/Lonsdale, Kilgard, Polletta, Smith, Owen, et al.)
•
•
•
•
•
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)
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Belinda Wilkes, 29 Nov 2007
Statistical Results
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)
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Belinda Wilkes, 29 Nov 2007
SWIRE/Chandra Survey
SWIRE X-ray Sample
• Standard R vs X plot
• Blue lines indicate
AGN region (not welldefined)
• Radio sources all
over
• Extended sources in
low L AGN region
R
X-ray
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Belinda Wilkes, 29 Nov 2007
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)
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Belinda Wilkes, 29 Nov 2007
IR
Optical
Obscured AGN
• Potential:
log NH ~ 21-24
– 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)
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Belinda Wilkes, 29 Nov 2007
Compton-thick AGN
(Polletta et al. 2006)
• 5 hard X-ray selected
(2 at z>2)
• 120 red, AGN-dominated, IRselected: 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
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Belinda Wilkes, 29 Nov 2007
SWIRE: X-ray Compton-Thick QSO
(Polletta et al. 2006)
•
•
•
•
SW 104409, z=2.54
X-ray HR~0.85, 11 cnts
NLSy1 optical spectrum
SED:
X-ray
– Obscured QSO, AV=4
– 0.6% QSO type 1
(scattered light)
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Belinda Wilkes, 29 Nov 2007
Optical/IR
Red AGN: Hard X-ray Spectra
Chandra data: Wilkes et al., in prep
• 44 2MASS Red (J-K>2)
AGN w/Chandra
• 21 spectral fits:
– Log NH~22
– PL slope flatter for
weaker X-rays
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Belinda Wilkes, 29 Nov 2007
XMM-Newton Observations
(Wilkes, Pounds et al. 2005, 2007)
• 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
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Belinda Wilkes, 29 Nov 2007
Complex Red Quasar: 2M1049+5837
Schmidt et al 2007
• 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
– Blue fan (3.5”
– Red fringe (polar, 2”)
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
Red
XMM-Newton Data
Wilkes, Pounds, Schmidt, in prep.
• 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%
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
Over-the-Top View
Courtesy
Charlotte
Garcia
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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!
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Belinda Wilkes, 29 Nov 2007
GRATING SPECTRA
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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
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Belinda Wilkes, 29 Nov 2007
JETS
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Belinda Wilkes, 29 Nov 2007
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!
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
M87 Jet in Radio and X-rays
Double-lobed radio
source with onesided relativistic jet
X-ray
Radio
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Belinda Wilkes, 29 Nov 2007
X-ray/Radio Jets in Quasars
M87 jet in X-ray, radio and optical
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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!
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
Double Quasar
Chandra: spatial + spectral
resolution
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
NGC 6240: Galaxy with Double X-ray Core
Starburst
LINER
z=0.0245
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Belinda Wilkes, 29 Nov 2007
NGC 6240: X-ray Spectrum
Fe Kα (6.4keV)
2
X-ray Astronomy # 12
2
Belinda Wilkes, 29 Nov 2007
NGC 6240 Movie
X-ray Astronomy # 12
Belinda Wilkes, 29 Nov 2007
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 # 12
Belinda Wilkes, 29 Nov 2007