THE FEATURELESS CONTINUA AND HYDROGEN LINES OF SEYFERT-2 GALAXIES

被引:106
作者
KINNEY, AL
ANTONUCCI, RRJ
WARD, MJ
WILSON, AS
WHITTLE, M
机构
[1] UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106
[2] UNIV OXFORD,DEPT ASTROPHYS,OXFORD OX1 3RH,ENGLAND
[3] UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742
[4] UNIV VIRGINIA,DEPT ASTRON,CHARLOTTESVILLE,VA 22903
关键词
GALAXIES; NUCLEI; SEYFERT; SPECTROPHOTOMETRY; ULTRAVIOLET; SPECTRA;
D O I
10.1086/170339
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present optical and ultraviolet spectra taken in similar sized large apertures for 15 Seyfert 2 galaxies. Measurements of emission-line strengths of Ly-alpha, H-alpha, and H-beta are used together with measurements of the ultraviolet slopes to estimate the ratio of recombination photons to ionizing photons. The photon ratios indicate that the ionizing continuum is being emitted anisotropically for at least six of the eight objects with UV slope measurements. The median value of the UV slope is alpha = -1.35 (F(nu) is-proportional-to nu-alpha), which is indistinguishable from the UV slope of Seyfert 1 galaxies. This result suggests that in the occultation/reflection picture of Seyfert nuclei, the reflecting particles are free electrons and not dust. We verify previous observations of variability in Mrk 477 and show that this galaxy exhibits characteristics of both Seyfert 1 and Seyfert 2 galaxies.
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页码:100 / 114
页数:15
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