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AGN in X-Ray Surveys For Astro597 Jian Wu November 10, 2004 OUTLINE Part I AGN Surveys in Different Bands Part II AGN X-ray Surveys Part I AGN Surveys in Different Bands AGN Surveys in different bands Retrospect Optical selection and implications Radio selection Infrared selection

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agn in x ray surveys

AGN in X-Ray Surveys

For Astro597

Jian Wu

November 10, 2004

outline
OUTLINE
  • Part IAGN Surveys in Different Bands
  • Part IIAGN X-ray Surveys
part i agn surveys in different bands
Part IAGN Surveys in Different Bands
  • AGN Surveys in different bands
    • Retrospect
    • Optical selection and implications
    • Radio selection
    • Infrared selection
    • High-Energy selection
  • Selection Effects
part ii agn x ray surveys
Part IIAGN X-ray Surveys
  • Soft X-rays Surveys
  • Hard X-ray Surveys
    • Pre-Chandra and XMM-Newton
    • Deep Chandra and XMM-Newton Surveys
  • Deep Extragalactic X-ray Surveys
  • 2Ms Chandra Point-Source CATA
part i

Part I

AGN Surveys in Different Bands

retrospect
Retrospect
  • Lamppost Effect
    • find something in where we can find it
  • Three types of surveys
    • Find object
    • Find object consistently
    • Find with well-defined selection criteria
retrospect7
Retrospect
  • First indication (optical)
    • NGC1068-broad emission lines (Fath, 1913)
    • M87-jet (Curtis 1917)
    • Extragalactic radio sources
    • The origin of name for quasar (Schmidt et.al., 1964)
retrospect8
Retrospect
  • Early AGN Surveys
    • Cambridge xC Surveys
    • Markarian Survey
    • Zwichky Survey
  • Recent Large Surveys
    • 2dF
    • SDSS
  • How to find AGN-SED
    • Power law (1013Hz-1020Hz)
    • Highly ionized Emission lines-C N O
    • Low-ionization emission lines-Fe
optical selection
Optical Selection
  • Principle (Sandage 1971)
    • Systematic optical color deviation from starlight
  • Bonus
    • Photometric red-shift estimation
  • Declaration of “complete samples”
  • Fatal bug
    • Lb does not correlated well with Lgalaxy→ cannot see low luminosity AGN in massive galaxies (contamination)
  • Aftermath
    • Omission (radio, IR, X-ray)
optical selection10
Optical Selection
  • Optical selection effect
    • Luminosities
    • Hard to evaluate
  • Alternatives
    • Variability
    • Absence of proper motion
radio selection
Radio Selection
  • Principles
    • Flat-spectrum, compact radio source
    • Object with low IR/radio
    • morphology
  • Advantages
    • Efficient
    • Sensitive
    • Accurate
    • Find objects omitted by optical techniques
  • Disadvantages
    • Incomplete (selection effect)
    • Star-forming region
infrared selection
Infrared Selection
  • Disadvantages
    • Color difference is subtle
    • Equivalent width insufficient
    • An Island
  • Potential advantages
    • mid-IR to be a “pivot point” in SED
    • PAH and high ionization IR lines
  • Prospect
    • SIRTF
high energy selection
High-Energy Selection
  • X-ray and γ-ray
  • Disadvantages
    • Soft X-ray suffer from larger extinction
    • Red-shift distribution
    • γ-ray position
    • Soft X-ray bias
selection effect
Selection Effect
  • Dilution of the optical/IR brightness and color by the starlight.
  • Obscuration
  • Another selection effect
part ii

Part II

AGN X-ray Surveys

advantages
Advantages
  • High contrast between AGN and stellar light
advantages17
Advantages
  • Penetrating power of X-rays.
advantages18
Advantages
  • Great sensitivity of Chandra and XMM-Newton
advantages19
Advantages
  • Accurate positions from Chandra
    • ~ 0.5 arcsec
advantages20
Advantages
  • A relatively large fraction of the bolometric energy (3-20%) is radiated in the classical X-ray bands.
  • High area density (400 deg-2)
  • Large amplitude and frequency of variability in the X-ray band.
  • Little Contamination from other objects
  • High red-shift quasars are easy to detect
  • Close to the black hole
early x ray surveys
Early X-ray Surveys
  • Uhuru (1970 10-1973 3) [2-20 keV]
  • Ariel-V (1973 10-1980 3) [0.3-40 keV]
  • HEAO-1 (1977 8-1979 1) [0.2keV-10MeV]
soft x ray surveys
Soft X-ray Surveys
  • Einstein (1978 11-1981 4) [0.2-20 keV]
  • ROSAT (1990 1-1999 2) [0.1-2.5 keV]
soft x ray surveys23
Soft X-ray Surveys
  • Fruit
    • Moderate correlation of optical and X-ray
hard x ray surveys
Hard X-ray surveys
  • ASCA (1993 2-2001 3) [0.4-10 keV]
  • BeppoSAX (1996 4-2002 4) [0.1-300 keV]
  • Fruit
    • ~ 500 serendipitous sources over ~ 100 deg2
deep chandra and xmm newton surveys
Deep Chandra and XMM-NewtonSurveys
  • Chandra (1999 7-present)
  • XMM-Newton (1999 10-present)
deep chandra and xmm newton surveys26
Deep Chandra and XMM-NewtonSurveys
  • Fruit
    • Numerous “optically dull” objects
    • Greatly enlarge the AGN population
deep extragalactic x ray surveys30
Deep Extragalactic X-ray Surveys
  • Source classification difficulties
    • Too faint to be identified by optical spectrum
    • Many of the X-ray sources have modest optical luminosities, often due to obscuration
    • “schism” between optical (type1 and type2) and X-ray (unobscured and obscured )
deep extragalactic x ray surveys32
Deep Extragalactic X-ray Surveys
  • Basic AGN Types
    • Unobscured AGN
    • Obscured AGN with clear optical/UV AGN signatures.
    • Optically faint X-ray sources
    • XBONGs

(X-ray Bright Optically Normal Galaxies)

agn red shift distribution

[Bargar et al. 2002]

[Bargar et al. 2003]

AGN Red-shift Distribution
  • Most AGN in deep X-ray surveys have z =0~2
  • Redshift distribution show “spikes” in z=0.5~2.5
agn selection completeness
AGN Selection Completeness
  • Reasons of incompleteness
    • Compton thick AGN
    • Luminous at non-X-ray, but X-ray weak
  • How many we haven’t seen

2000-3000 deg-2

key results from dexs
Key results from DEXS
  • Large optically selected luminous quasars
    • PLE (Pure luminosity Evolution)
  • Moderate-luminosity AGN
    • LDDE (luminosity-dependent density evolution)
x ray constraints
X-ray constraints
  • Sky density
    • Bottom line (z > 4) ~ 30-150 deg-2
    • AGN contribution to reionization at z ~ 6 is small
  • Accretion[z>4] ~ Accretion[local]
  • Infrared and sub-millimeter
    • star-forming processes
  • AGN/sub-mm galaxies >=40%.
  • X-ray survey should remain an effective way to find AGN at the highest redshift
future prospects
Future prospects
  • Detailed cosmic history of SMBH accretion
  • The nature of AGN activity in young, forming galaxies
  • X-ray measurements of clustering and large-scale structure
  • The X-ray properties of cosmologically distant starburst and normal galaxies
the 2ms cdf n
Main CATAlog

High significant Chandra sources

Supplementary CATAlog

Lower significance Chandra sources

The 2Ms CDF-N

20 observations

447.8 arcmin2

Flux limit=2.5×10-17 erg cm-2 s-1 (0.5-2.0 keV)

Flux limit=1.4 ×10-16 erg cm-2 s-1 (2.0-8.0 keV)

data reduction
CIAO

Chandra Interactive Analysis of Observations

Radiation damage

Quantum Efficiency Losses

Bad column

Bad pixel

Cosmic ray afterglow

Standard pixel randomization

Potential background events

Data reduction
production of catalogs
Technique feature

Matched filter

Accuracy of the X-ray source position

Correlation of optically bright sources with lower significance Chandra sources

Production of CATAlogs
standard bands

FB

HB

SB1

SB

SB2

HB1

HB2

keV

Standard Bands
point source detection

False positive probability 1×10-7

main CATAlog

1×10-5

supplementary optically bright source CATAlog

Point-source Detection
  • Key criterion
source position refinement
Source Position Refinement

X –ray

1.4GHz Radio

503 sources

prospects

Longer and longer

Prospects
  • Doubling the exposure of a Chandra observation leads to an increase in sensitivity between and .
  • The number of background counts is often negligible.
  • Negative K-correction of absorbed AGN emission