We investigated a total of 156 RASS sources and an additional number of 79 sources from pointed observations. On average, there were about two candidate counterparts per source. With regard to the discussion of candidate selection on the basis of X-ray hardness ratios below, we stress that all the investigated sources have been selected at random from the input source lists, regardless of their hardness ratios or X-ray luminosity.
A star was classified as TTS if
it showed a late spectral type (F or later), and a Li I 
absorption line with an equivalent width 
of
.
Stars classified as TTS were subdivided in WTTS and CTTS on the basis
of their 
emission.
If 
was present in emission above the
photospheric continuum with an equivalent width 
in excess of 10 Å, the star was classified as CTTS, otherwise
as WTTS. However, we did not use the presence of 
emission
as indicator for the pre-main sequence nature of a star, because
some late-type main sequence stars have significant
emission, while in some PMS stars the 
emission may
not even fill up the photospheric absorption.
Of 156 RASS sources studied so far, 86 have been identified with TTS. In three cases two TTS were found within the error circle, thus the total number of TTS found on the basis of the RASS is 89 (86 WTTS and 3 CTTS). Additionaly, out of 92 sources of pointed observations we studied, 46 could be identified with TTS. In one case two TTS were found within the error circle, thus 47 additional TTS (45 WTTS and 2 CTTS) were found on the basis of the pointed observations.
The new WTTS found in our study are listed in Table 5. If possible, stars are named by a catalog identifier, otherwise the RASS source name is given. Whenever possible, the coordinates are taken from the Hubble Guide Star Catalog (GSC).
During our survey, 44 stars of spectral type K to M were found, which
displayed 
in emission above the continuum, but most probably are
not PMS stars, as none of them shows obvious Li I 
absorption.
These stars are listed in Table 6.
As we do not have photometric
data for these stars, we cannot make any statement concerning their distance
or a possible association with the Lupus SFR.
The number of these stars is within the expected range, as a comparison
with the EINSTEIN Medium Sensitivity Survey (EMSS; Stocke et al. 1991)
shows. The EMSS has a limiting sensitivity ranging from
to 
,
which is comparable to the sensitivity of the RASS. 26% of the
EMSS sources were identified with galactic stars, most of them
active late-type dwarfs.
We identified this source with a CTTS with strong 
emission
(
) and marked emission in 
,
HeI 
, 6678, and [OI] 
.
This star is identical with Thé 11 (Thé 1962).
Although
the star is only about 
from the center of plate CS 19279 of the
objective prism survey carried out by Schwarz (1977), it is not
listed in the paper, and apparently has never been studied in more detail.
This star may exhibit
strong variability in the 
line,
which could be the reason why it has not
been found by Schwarz (1977).
In the error circle of this source we found a star of spectral type M4
with a rather strong 
emission (
).
Also 
and HeI 
are in emission. However, although
the 
emission is much stronger than usually found for
dMe-stars, no LiI 
absorption could be found. As the
absorption spectrum of this star is relatively weak in comparison with
other stars of the same spectral type, we suspect that
the LiI line might be hidden by veiling and tentatively identify this
object as CTTS candidate.