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Measurement of the Broad Line Region Size in Two Bright Quasars

Shai Kaspi·Paul S. Smith·Dan Maoz·Hagai Netzer·Buell. T. Jannuzi
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Abstract

We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and emission line variations. The variations of the H$β$ line follow those of the continuum with a time lag, as derived from a cross-correlation analysis, of 93$\pm$30 days for PG 0804+762 and 111$\pm$55 days for PG 0953+414. This is the first reliable measurement of such a lag in active galactic nuclei with luminosity $L>10^{45}$ erg s$^{-1}$. The broad line region (BLR) size that is implied is almost an order of magnitude larger than that measured in several Seyfert 1 galaxies and is consistent with the hypothesis that the BLR size grows as $L^{0.5}$.

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Shai Kaspi, Paul S. Smith, Dan Maoz, Hagai Netzer, Buell. T. Jannuzi. 1996-08-29. Measurement of the Broad Line Region Size in Two Bright Quasars. https://doi.org/10.1086/310339

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