1 / 16

Extending α OX Studies to Include the Numerous Low-to-Moderate Luminosity AGNs

Investigate αOX studies on low-to-moderate luminosity AGNs to break the redshift degeneracy. Utilize statistical tests on large AGN samples to explore αOX evolution over cosmic time.

dclark
Download Presentation

Extending α OX Studies to Include the Numerous Low-to-Moderate Luminosity AGNs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Extending αOX Studies to Include the Numerous Low-to-Moderate Luminosity AGNs • Aaron Steffen • The Pennsylvania State University • November 6th, 2006

  2. Collaborators Iskra Strateva MPE Niel Brandt PSU Franz Bauer Columbia David Alexander Durham, U.K. Anton Koekemoer STScI Bret Lehmer PSU Don Schneider PSU Cristian Vignali INAF - Bologna

  3. Project Motivation ● Extend αOX 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 αOX 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

  4. 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)

  5. Breaking the L-z Degeneracy

  6. Comparing LUV and LX vs. redshift Our sample spans 5 (4) orders of magnitude in LUV (LX).

  7. OLS Bisector yields: Non-parametric Kendall’s partial τ= 0.519 (15σ) X-ray vs. Optical Luminosity

  8. Non-parametric Kendall’s partial τ= −0.377 (14σ) Evidence for a non-linear relation Dependance of αOX on log(LUV)

  9. No Evidence for Evolution Parametric Non-Parametric Kendall’s Partial τ = −0.031 (1.3σ)

  10. AT86 W94 S05 S06 Number of Sources 154 343 228 333 % X-ray Detected 61% 52% 86% 88% Radio Loud or BALs? Yes Yes No No Comparison with Earlier Studies

  11. Future Studies: Including the Most Luminous AGNs

  12. Still no Evidence for Cosmic Evolution

  13. Are the COMBO-17 selected AGNs the Faint Extension of the SDSS Population?

  14. COMBO-17 αOX Distrbution

More Related