1998A&A...329..863T


Query : 1998A&A...329..863T

1998A&A...329..863T - Astronomy and Astrophysics, volume 329, 863-872 (1998/1-3)

Principal component analysis of two ultraviolet emission-lines in 18 active galactic nuclei.

TUERLER M. and COURVOISIER T.J.-L.

Abstract (from CDS):

We apply a principal component analysis (PCA) to the spectra of each of the 18 Seyfert 1-like objects observed more than 15 times by the international ultraviolet explorer (IUE) from 1978 until the end of 1991. PCA allows us to decompose the Lyα and C IV λ1549 emission-lines of each object into two components with uncorrelated variations. We find that the principal component describes correlated continuum and line variations, whereas the rest component reveals the line-parts that do not vary in tune with the continuum. A cross-correlation analysis in NGC 5548 reveals that variable line features in the rest component follow the continuum by about 25 days. The symmetry usually observed in the component's line profiles excludes that the velocity field of the line-emitting region is dominated by radial motion. In some objects, the principal component reveals a clearly double-peaked line profile. The results suggest that the variable line feature in the principal and the rest component is respectively emitted in the inner and outer parts of an extended broad-line region (BLR). The fraction of the line that varies together with the continuum seems to decrease significantly with increasing luminosity. We interpret this trend as a consequence of a larger BLR in more luminous objects. Finally, we propose a solution to the C IV/Lyα ratio problem without referring to optically thin emission-line clouds.

Abstract Copyright:

Journal keyword(s): line: profiles - galaxies: active - quasars: emission lines - galaxies: Seyfert - ultraviolet: galaxies

Simbad objects: 19

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Number of rows : 19
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 Mrk 335 Sy1 00 06 19.5372339024 +20 12 10.617404076   14.19 13.85     ~ 1171 0
2 ESO 113-45 Sy1 01 23 45.7631533440 -58 48 20.808928944   14.08 13.83 13.34   ~ 815 0
3 NGC 863 Sy1 02 14 33.5604714720 -00 46 00.181845336   14.48 13.81 17.9   ~ 631 0
4 Mrk 1506 Sy1 04 33 11.0956735296 +05 21 15.619461552   15.72 15.05 10.08   ~ 1915 2
5 Mrk 1095 Sy1 05 16 11.4092471904 -00 08 59.157166920   14.30 13.92     ~ 834 1
6 NGC 3516 Sy1 11 06 47.4632200800 +72 34 07.298374656   13.12 12.40     ~ 1471 0
7 NGC 3783 Sy1 11 39 01.7096819040 -37 44 19.009642992   12.46 13.43 11.33 12.1 ~ 1551 0
8 LEDA 38224 Sy1 12 04 42.1097215992 +27 54 11.869350264   15.64 15.60     ~ 367 0
9 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3520 2
10 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5555 1
11 NGC 4593 Sy1 12 39 39.4435107024 -05 20 39.034988448   13.95 13.15     ~ 1011 0
12 Mrk 279 Sy1 13 53 03.4348964112 +69 18 29.410910460   15.15 14.46     ~ 719 0
13 NGC 5548 Sy1 14 17 59.5400291832 +25 08 12.603122268   14.35 13.73     ~ 2530 0
14 ICRF J183503.3+324146 Sy1 18 35 03.3896172576 +32 41 46.855964616   16.50 15.39 10.50   ~ 610 1
15 ICRF J184208.9+794617 Sy1 18 42 08.9904975672 +79 46 17.127835104   16.06 15.38     ~ 1258 0
16 ESO 141-55 Sy1 19 21 14.1473895816 -58 40 12.982437480   14.36 13.64 13.28   ~ 338 0
17 Mrk 509 Sy1 20 44 09.7504483224 -10 43 24.727155528   13.35 13.12 10.7   ~ 1197 0
18 NGC 7469 Sy1 23 03 15.674 +08 52 25.28 12.60 13.00 12.34     ~ 1989 3
19 Mrk 926 Sy1 23 04 43.4776098480 -08 41 08.629476864   16.20 15.91 9.4   ~ 423 0

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2022.05.20-20:01:19

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