Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21322001m&link_type=abstract
American Astronomical Society, AAS Meeting #213, #220.01; Bulletin of the American Astronomical Society, Vol. 41, p.390
Astronomy and Astrophysics
Astronomy
Scientific paper
A substantial fraction of the distant absorbed AGNs detected in the Chandra Deep Fields (CDFs) lack optical evidence of nuclear activity in follow-up observations. However, it remains unclear whether the differences between nearby and distant AGNs are real or largely apparent in nature. Samples of of these objects are assembled in very different ways, which affects the portions of the luminosity functions they represent. Moreover, the data normally acquired for nearby and distant galaxies differ greatly. For example, emission from the nucleus can be isolated for nearby objects, whereas only the integrated emission of distant galaxies can be obtained at most wavelengths. The program described in this talk aims to characterize the multiwavelength properties of nearby absorbed AGNs and their host galaxies in a way that facilitates a meaningful direct comparison to the absorbed AGNs detected in the CDFs. To accomplished this, we have used a number of NASA-supported data archives to assemble the spectral energy distributions (SEDs) of the integrated emission of a large, unbiased sample of nearby Seyfert 2 galaxies. We have examined the SEDs of the local objects for correlations in their overall shape that might be driven by the contrast between the nucleus and host galaxy in the integrated light, and have derived the median values and effective 1-sigma ranges of their luminosities at all frequencies. A comparison of the SEDs of individual absorbed AGNs from the CDFs to those of the local sample, properly accounting for redshift effects and the way the intrinsic luminosity function is sampled in deep pencil-beam surveys, reveals essentially no differences between nearby absorbed AGNs and those detected in the CDFs. This suggests that observational factors -- host-galaxy dilution, redshift effects, and signal-to-noise ratio -- are mainly responsible for the normal appearance of distant absorbed AGNs in ground-based observations.
No associations
LandOfFree
Distant Active Galaxies: Insights from the Local Population does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Distant Active Galaxies: Insights from the Local Population, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Distant Active Galaxies: Insights from the Local Population will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1696585