Akinari NAKAGAWA*

Dipartimento di Astronomia e Scienza dello Spazio, Università degli Studi di Firenze, Largo Enrico Fermi, 5-50125 Firenze, Italia

(Received March 14, 2002; Revised October 9, 2002; Accepted October 11, 2002)

It has been noticed that observed spectral line profiles by the SOHO ultraviolet coronagraph spectrometer (SOHO/UVCS) are contaminated by a so-called detector effect, and an iterative correction of observed profiles by convolution with a zero-integral function has been employed to remove this unwanted effect on UVCS detectors. It is shown here that this iteration procedure using a zero-integral function can be replaced by an only-once application of convolution. For zero-integral functions of exp[-|x|/L]-type, the convolution function in this method is proved to have exactly the same, but narrower (steeper), functional form as the original one. These results are also valid, with some modifications, for the discrete case used in numerical calculation.

Key words: solar corona, SOHO/UVCS, coronagraph spectrometer, detector effect, profile correction, zero-integral function, convolution