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WAS 49 - MIRROR FOR A HIDDEN SEYFERT-1 NUCLEUS
被引:41
作者:
MORAN, EC
HALPERN, JP
BOTHUN, GD
BECKER, RH
机构:
[1] UNIV OREGON,DEPT PHYS,EUGENE,OR 97403
[2] UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616
[3] LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550
关键词:
D O I:
10.1086/116292
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
Was 49 is an interacting system of galaxies at z=0.063 containing two Seyfert nuclei. Spectra of the nuclei indicate that Was 49a is a normal Seyfert 2, while Was 49b is a "hidden" Seyfert 1 as indicated by its strong narrow emission lines, weak broad Balmer lines, and weak featureless continuum. Spatially resolved long-slit spectra of Was 49 show strong, extended emission lines throughout the system. These provide independent evidence for a powerful source of ionizing radiation that is obscured from our line of sight. We have derived estimates of the intrinsic ionizing luminosities of both nuclei on the basis of standard photoionization models applied to the extended emission lines. These calculations show that Was 49a is not significantly obscured, but that Was 49b is approximately 200 times more luminous than it is observed to be and is chiefly responsible for the photoionization of the interstellar medium of its companion. The intrinsic high-energy luminosity of Was 49b is predicted to be > 10(45) erg s-1. We also observed Was 49 with the VLA. The radio luminosity of Was 49b places it on the high-luminosity tail of the Seyfert radio luminosity function, along with all eight other published examples of hidden Seyfert I's. We conclude that the extreme radio luminosity of hidden Seyfert I's is an intrinsic property of these objects, and rules out the strong version of the unified Seyfert scheme in which Seyfert classification is purely a viewing angle effect. Some Seyfert 2 galaxies must then be "true" Seyfert 2's.
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页码:990 / 999
页数:10
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