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Astron. Astrophys. 323, 5-13 (1997)


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Balmer emission-line profile variations in NGC 4593

W. Kollatschny 1 and M. Dietrich 2

1 Universitäts-Sternwarte Göttingen, Geismarlandstraße 11, D-37083 Göttingen, Germany
2 Landessternwarte Heidelberg, Königstuhl, D-69117 Heidelberg, Germany,

Received 26 March 1996 / Accepted 9 August 1996

Abstract

We present results of a variability campaign of Balmer line profiles in NGC 4593. The continuum and the broad emission line intensities varied up to 50 per cent during the observing period. The rms profiles of the Balmer lines as well as the difference line profiles can be described by a limited number of strong components only: a central component and two to four outer components which are located more or less symmetrically with respect to [FORMULA] = 0 km s-1. The components varied neither simultaneously nor with the same amplitude. But there is a trend that the pairwise components varied in a similar way. The outer line wings responded nearly simultaneously within of 2 days to continuum variations. The inner regions of the line profiles responded within about 5 days. Strong radial motions can be excluded to be dominant in the BLR. Indications have been found for the appearance or disappearance of line profile components within a few days only. The BLR seems to be clumpy and to consist of a limited number of clouds or cloud complexes only. These clouds or the ionizing source might have a bidimensional structure.

Key words: galaxies: individual: NGC4593 – galaxies: Seyfert – lines: profiles

Send offprint requests to: W. Kollatschny

© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998

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