The 1450 - 1720 Å spectral region of NGC 4151 is analyzed by means of Gaussian decomposition for 69 different epochs, from early 1978 to the end of 1983. The C IV λ1550 emission profile is well represented by a core, whose full width at half-maximum varies between 2600 and 5500 km s-1, and an ultrabroad component (14,600 km s-1). The variations of the ultrabroad feature suggest that it originates in a region whose "radius" is ≡5 lt-day. The analysis of lines from He II, C III], N IV] and O III] indicates the presence of two additional discrete broad line subregions. A study of the velocity dispersions indicates that the motion of the gas is Keplerian and yields a value of (3.7±0.5)×107M_sun; for the central mass. A correlation is found between the wavelength of the ultrabroad C IV λ1550 component and its intensity. It strongly suggests the existence of a decelerated outflow whose velocity is 4000 km s-1 at 5 lt-day from the nucleus.
Clavel, J., Altamore, A., Boksenberg, A., Bromage, G.e., Elvius, A., Pelat, D., et al. (1987). A DETAILED STUDY OF THE C-IV-LAMBDA-1550 LINE-PROFILE AND ADJACENT SPECTRAL FEATURES IN NGC-4151 FROM 1978 TO 1983. THE ASTROPHYSICAL JOURNAL, 321(1), 251-279 [10.1086/165628].
A DETAILED STUDY OF THE C-IV-LAMBDA-1550 LINE-PROFILE AND ADJACENT SPECTRAL FEATURES IN NGC-4151 FROM 1978 TO 1983
ALTAMORE, Aldo;
1987-01-01
Abstract
The 1450 - 1720 Å spectral region of NGC 4151 is analyzed by means of Gaussian decomposition for 69 different epochs, from early 1978 to the end of 1983. The C IV λ1550 emission profile is well represented by a core, whose full width at half-maximum varies between 2600 and 5500 km s-1, and an ultrabroad component (14,600 km s-1). The variations of the ultrabroad feature suggest that it originates in a region whose "radius" is ≡5 lt-day. The analysis of lines from He II, C III], N IV] and O III] indicates the presence of two additional discrete broad line subregions. A study of the velocity dispersions indicates that the motion of the gas is Keplerian and yields a value of (3.7±0.5)×107M_sun; for the central mass. A correlation is found between the wavelength of the ultrabroad C IV λ1550 component and its intensity. It strongly suggests the existence of a decelerated outflow whose velocity is 4000 km s-1 at 5 lt-day from the nucleus.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
