Extending aOX Studies to Include the Numerous Low-to-Moderate Luminosity AGNs

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Extending aOX Studies to Include the Numerous
Low-to-Moderate Luminosity AGNs

• Aaron Steffen
• The Pennsylvania State University
• November 6th, 2006

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Collaborators
Iskra Strateva MPE
Niel Brandt PSU
David Alexander Durham, U.K.
Franz Bauer Columbia
Anton Koekemoer STScI
Bret Lehmer PSU
Don Schneider PSU
Cristian Vignali INAF - Bologna
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Project Motivation
? Extend aOX studies to include the
low-to-moderate luminosity AGNs that numerically
dominate the AGN population.
? Break the luminosity - redshift degeneracy
present in flux-limited samples.
? Compile a large, homogeneous AGN sample and use
both parametric and non-parametric statistical
tests to determine if aOX evolves with cosmic
time.
COMBO-17 (Wolf et al. 2004) Optically selected
AGNs using 5 Broad-band and 12 Medium-band filters
Extended Chandra Deep Field - South (E-CDF-S
Lehmer et al. 2005) Four contiguous 250 ks ACIS-I
exposures centered on the 1Ms CDF-S
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Relation Between UV and X-ray Emission in AGN
Sobolewska, Siemiginowska Zycki (2004)
? UV emission from a thermalized thin accretion
disk. ? X-ray emission from inverse-Compton
scattering off of energetic electrons in
optically thin corona. ? Radio jets and intrinsic
absorption can affect the measurement of the
intrinsic X-ray/UV emission.
Richards et al. (2006)
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Breaking the L-z Degeneracy
Sample srcs X-ray Detected
Strateva et al. (2006) Strateva et al. (2006) Strateva et al. (2006)
Seyfert 1s 25a 25 (100)
SDSS / ROSAT 155 126 (81)
High-z 36 32 (89)
Sample srcs X-ray Detected
Strateva et al. (2006) Strateva et al. (2006) Strateva et al. (2006)
Seyfert 1s 25a 25 (100)
SDSS / ROSAT 155 126 (81)
High-z 36 32 (89)
Steffen et al. (2006) Steffen et al. (2006) Steffen et al. (2006)
BQS / ROSAT 46 45 (98)
COMBO-17 / E-CDF-S 52 47 (90)
High-z 19 32 (89)
Total 333 293 (88)
Sample srcs X-ray Detected
Strateva et al. (2006) Strateva et al. (2006) Strateva et al. (2006)
Seyfert 1s 25a 25 (100)
SDSS / ROSAT 155 126 (81)
High-z 36 32 (89)
Steffen et al. (2006) Steffen et al. (2006) Steffen et al. (2006)
BQS / ROSAT 46 45 (98)
COMBO-17 / E-CDF-S 52 47 (90)
High-z 19 32 (89)
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Comparing LUV and LX vs. redshift
Our sample spans 5 (4) orders of magnitude in LUV
(LX).
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X-ray vs. Optical Luminosity
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Dependance of aOX on log(LUV)
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No Evidence for Evolution
Parametric
Non-Parametric
Kendalls Partial t -0.031 (1.3s)
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Comparison with Earlier Studies
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Future Studies Including the Most Luminous AGNs
Sample srcs X-ray Detected
Strateva et al. (2006) Strateva et al. (2006) Strateva et al. (2006)
Seyfert 1s 25a 25 (100)
SDSS / ROSAT 155 126 (81)
High-z 36 32 (89)
Steffen et al. (2006) Steffen et al. (2006) Steffen et al. (2006)
BQS / ROSAT 46 45 (98)
COMBO-17 / E-CDF-S 52 47 (90)
High-z 19 32 (89)
Total 333 293 (88)
Sample srcs X-ray Detected
Strateva et al. (2006) Strateva et al. (2006) Strateva et al. (2006)
Seyfert 1s 25a 25 (100)
SDSS / ROSAT 155 126 (81)
High-z 36 32 (89)
Steffen et al. (2006) Steffen et al. (2006) Steffen et al. (2006)
BQS / ROSAT 46 45 (98)
COMBO-17 / E-CDF-S 52 47 (90)
High-z 19 18 (89)
Just et al. (2007) Just et al. (2007) Just et al. (2007)
SDSS / Chandra 30 30 (100)
High-z 19 14 (74)
Total 382 337 (88)
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Still no Evidence for Cosmic Evolution
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Are the COMBO-17 selected AGNs the Faint
Extension of the SDSS Population?
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COMBO-17 aOX Distrbution
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