Astronomy and Astrophysics – Astronomy
Scientific paper
Apr 1990
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990phdt........29m&link_type=abstract
Ph.D. Thesis Tel-Aviv Univ. (Israel).
Astronomy and Astrophysics
Astronomy
Active Galactic Nuclei, Astronomical Spectroscopy, Emission Spectra, Galactic Structure, Line Spectra, Size Determination, Astronomical Models, Cross Correlation, Photoionization, Quasars, Reference Stars, Seyfert Galaxies, Variations
Scientific paper
This work investigates the size, structure and kinematics of the Broad Line Region (BLR) of Active Galactic Nuclei (AGN), as reflected through emission line variability. It includes an analysis of previous variability studies and new observational results, which are presented and analyzed. A numerical method is developed to evaluate the significance of the cross-correlation technique, as applied to the measurement of AGN emission line region sizes. It shows that such results and their significance are strongly dependent upon geometrical assumptions. When applied to published data for Akn 120 and NGC 4151, the method shows that estimates for the size of BLR do not significantly contradict the predictions of photoionization models, and that measurements with a much higher sampling frequency and lower measurement error are needed for this. An intensive monitoring project was carried out for 7 months at the Wise Observatory, in which a sample of 11 Seyfert 1 galaxies and three quasars was observed spectroscopically on an almost nightly basis. A novel calibration technique, in which each object was observed simultaneously with a field star, resulted in very accurate measurements. In terms of both the sampling rate and the measurement errors, this project constitutes a factor of 3-5 improvement over the best previous efforts. An accurate measurement of the size of the BLR in three objects which underwent large enough variations (Mrk 279, NGC 5548 and NGC 4151) confirms for the first time the small sizes suggested by the earlier studies.
No associations
LandOfFree
Emission line variability in active galactic nuclei 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 Emission line variability in active galactic nuclei, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Emission line variability in active galactic nuclei will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1383062