Статья

Steps toward Determination of the Size and Structure of the Broad‐Line Region in Active Galactic Nuclei. IX. Ultraviolet Observations of Fairall 9

P. M. Rodriguez‐PascualESA IUE Observatory, P.O. Box 50727, 28080 Madrid, SpainD. AlloinCentre d'Etudes de Saclay, Service d'Astrophysique, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, FranceJ. ClavelISO Project, European Space Agency, Apartado 50727, 28080 Madrid, SpainD. M. CrenshawComputer Sciences Corporation, Laboratory for Astronomy and Solar Physics, NASA/Goddard Space Flight Center, Code 681, Greenbelt, MD 20771K. HorneSchool of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, Scotland, UKG. A. KrissDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218Julian H. KrolikDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218Matthew A. MalkanDepartment of Astronomy, University of California, Math-Science Building, Los Angeles, CA 90024H. NetzerSchool of Physics and Astronomy and the Wise Observatory, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, IsraelP. T. O’BrienDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, England, UKB. M. PetersonDepartment of Astronomy, Ohio State University, 174 West 18th Avenue, Columbus, OH 43210G. A. ReichertNASA/Goddard Space Flight Center, Code 631, Greenbelt, MD 20771W. WamstekerESA IUE Observatory, P.O. Box 50727, 28080 Madrid, SpainTal AlexanderSchool of Physics and Astronomy and the Wise Observatory, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, IsraelP. BarrISO Project, European Space Agency, Apartado 50727, 28080 Madrid, SpainR. D. BlandfordTheoretical Astrophysics, Caltech 130-33, Pasadena, CA 91125Joel N. BregmanDepartment of Astronomy, University of Michigan, Dennison Building, Ann Arbor, MI 48109T. E. CaronePresent address: 28740 West Fox River Drive, Cary, IL 60013S. D. ClementsDepartment of Astronomy, University of Florida, P.O. Box 112055, 211 SSRB, Gainesville, FL 32611-2055T. J.-L. CourvoisierObservatoire de Genève, CH-1290 Sauverny, SwitzerlandM. M. De RobertisDepartment of Physics and Astronomy, York University, 4700 Keele Street, North York, ON M3J 1P3, CanadaM. DietrichH. DottoriDepartamento de Astronomia, Instituto de Física, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CP15051, CEP 91500, Porto Alegre, RS, BrazilRick EdelsonDepartment of Physics and Astronomy, University of Iowa, Iowa City, IA 52242A. V. FilippenkoDepartment of Astronomy, University of California, Berkeley, CA 94720-3411C. M. GaskellDepartment of Physics and Astronomy, University of Nebraska, Lincoln, NE 68588J. P. HuchraHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138J. B. HutchingsDominion Astrophysical Observatory, 5071 West Saanich Road, Victoria, B.C. V8X 4M6, CanadaW. KollatschnyUniversitäts-Sternwarte Göttingen, Geismarlandstrasse 11, D-37083 Göttingen, GermanyAnuradha KoratkarSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218K. T. KoristaDepartment of Physics and Astronomy, University of Kentucky, Lexington, KY 40506Ari LaorPhysics Department, Technion Israel Institute of Technology, Haifa 32000, IsraelG. M. MacAlpineDepartment of Astronomy, University of Michigan, Dennison Building, Ann Arbor, MI 48109P. G. MartinCanadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8, CanadaDan MaozSchool of Physics and Astronomy and the Wise Observatory, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, IsraelB. McCollumComputer Sciences Corporation, NASA/Goddard Space Flight Center, Code 684.9, Greenbelt, MD 20771S. L. MorrisDominion Astrophysical Observatory, 5071 West Saanich Road, Victoria, B.C. V8X 4M6, CanadaG. C. PerolaIstituto Astronomico dell'Università, Via Lancisi 29, I-00161 Rome, ItalyRichard W. PoggeDepartment of Astronomy, Ohio State University, 174 West 18th Avenue, Columbus, OH 43210R. PtakDepartment of Physics and Astronomy, Bowling Green State University, Bowling Green, OH 43403Carmen RecondoFacultad de Ciencias, Departament de Físicas, Universidad de Oviedo, C/Calvo Sotelo, s/n. Oviedo, Asturias, SpainJ. M. Rodriguez‐EspinozaInstituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, SpainE. RokakiRoyal Observatory Edinburgh, University of Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, Scotland, UKM. Santos‐LleóLAEFF, Apartado 50727, E-28080 Madrid, SpainK. SekiguchiSouth African Astronomical Observatory, P.O. Box 9, Observatory 7935, South AfricaJ. Michael ShullJoint Institute for Laboratory Astrophysics, University of Colorado and National Institute of Standards and Technology, Campus Box 440, Boulder, CO 80309M. A. J. SnijdersIRAM, 300 Rue de la Piscine, 38046 Saint Martin d'Heres, FranceL. S. SparkeG. M. StirpeOsservatorio Astronomico di Bologna, Via Zamboni 33, I-40126, Bologna, ItalyR. StonerDepartment of Physics and Astronomy, Bowling Green State University, Bowling Green, OH 43403Wei‐Hsin SunInstitute of Astronomy, National Central University, Chung-Li, Taiwan 32054, Republic of ChinaS. J. WagnerI. WandersDepartment of Astronomy, Ohio State University, 174 West 18th Avenue, Columbus, OH 43210B. J. WilkesHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138C. WingeDepartamento de Astronomia, Instituto de Física, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CP15051, CEP 91500, Porto Alegre, RS, BrazilWei ZhengDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218

1997en

ABI

Аннотация

An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum-emission-line delays for a high-luminosity active galactic nucleus (AGN). While the results of this campaign are more ambiguous than those of previous monitoring campaigns on lower luminosity sources, we find general agreement with the earlier results: (1) there is no measurable lag between ultraviolet continuum bands, and (2) the measured emission-line time lags are very short. It is especially notable that the Lyα + N V emission-line lag is about 1 order of magnitude smaller than determined from a previous campaign by Clavel, Wamsteker, & Glass (1989) when Fairall 9 was in a more luminous state. In other well-monitored sources, specifically NGC 5548 and NGC 3783, the highest ionization lines are found to respond to continuum variations more rapidly than the lower ionization lines, which suggests a radially ionization-stratified broad-line region. In this case, the results are less certain, since none of the emission-line lags are very well determined. The best-determined emission line lag is Lyα + N V, for which we find that the centroid of the continuum-emission-line cross-correlation function is τcent ≈ 14-20 days. We measure a lag τcent lesssim 4 days for He II λ1640; this result is consistent with the ionization-stratification pattern seen in lower luminosity sources, but the relatively large uncertainties in the emission-line lags measured here cannot rule out similar lags for Lyα + N V and He II λ1640 at a high level of significance. We are unable to determine a reliable lag for C IV λ1550, but we note that the profiles of the variable parts of Lyα and C IV λ1550 are not the same, which does not support the hypothesis that the strongest variations in these two lines arise in the same region.

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Идентификаторы

DOI: 10.1086/312996

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