Appendix A. Comments

We present here individual comments and notes for a set of disturbed HI spectra which were recognized as possibly confused. For the objects marked with an "a" in Table 2, it was possible to measure both the line width and the systemic velocity. The objects marked with a "c" have been definitely classified as HI-confused galaxies, either their HI profile is distorted by the HI emission of a close companion, or it is atypical, due to some internal features or tidal effects. However, we give in Table 2 the velocity corresponding to the center of the detected signal.

Some of the results presented in Table 2 refer to HI observations that were done almost 10 years ago; for those galaxies, it was not possible to read the original files containing the spectra, they are thus not given in Fig. 5. These 62 objects are marked with a star in Table 2.

P0366, UGC 36: Already measured at 21-cm (V=6291 km s^-1) by Lu et al. (1993). Given as pair in Nilson catalogue with UGC 34, also in the beam at V=6134 km s^-1. HI confusion.

P1746, UGC 282: Pair with UGC 283, both galaxies are in the center of the beam. Previously measured in HI at V=4032 km s^-1 and V=3854 km s^-1 respectively (LEDA). The emission of UGC 283 is seen on the left edge of the main profile.

P2352, NGC 192: 3 galaxies in the beam: NGC 192, NGC 196 and NGC 197, known to have respectively V=4210 km s^-1, V=4238 km s^-1, and V=4176 km s^-1, according to Hickson et al. (1993). NGC 196 (T=-2)^S and NGC 197 (T=-1) are lenticular and consequently rather hydrogen poor. However, considering the atypical shape of the HI profile, NGC 196 and NGC 197 should contribute to the emission line.

P2357, NGC 196: HI confusion, see P2352.

P3442, NGC 317A: 3 objects in the beam: NGC 317 (lenticular, V=5305 km s^-1 -Karachentsev et al. 1979-, V=5283 km s^-1 -Tift et al. 1982), NGC 317B (Sb, V=5326 km s^-1 -LEDA, HI measurement-), and MCG 7-3-11 (Scd, V=5422 km s^-1 -Rubin et al. 1976, HI measurement-). Most probable HI confusion.

P6966: 2 companions according to Vorontsov-Velyaminov at 2'4 and 3'0 (B=15 mag). Strange double shape HI profile, certainly HI confusion.

P8173, NGC 825: Also IC208 (Sbc, face-on galaxy) in the beam. NGC 825 (Sa, edge-on) is expected at V=3398 km s^-1 according to Chengalur et al. (1993, HI measurement). The narrow HI profile expected for IC208 is clearly seen at $V\simeq3520$ km s^-1 and confirms previous optical measurements at V=3449 km s^-1 (White et al. 1983) and V=3504 km s^-1 (Karachentsev 1987). However, NGC 825's emission probably contributes to the total width of the observed HI profile centered at $V\simeq3400$ km s^-1.

P8225, NGC 835: Paired galaxies probably in interaction (NGC 835 and NGC 833, ARP318, HICK 16A and 16B). Both are in the beam at V=3853 km s^-1 (Martin et al. 1991, HI measurement for NGC 835) and V=3899 km s^-1 (LEDA, for NGC 833). Probably HI confusion.

P8228, NGC 833: See P8225.

P9849, UGC 2028: 4 galaxies in the beam: UGC 2028 (Sdm), MCG 7-6-40 (Sa), and the pair galaxy UGC 2063 (lenticular, V=5757 km s^-1, from Magri 1994, HI measurement) and UGC 2066 (Sa, V=5873 km s^-1, from Haynes et al. 1988, HI measurement). the two former are satellites of the pair, the rotation of UGC 2028 is distorted by his companions. Most probably HI confusion.

P13283: Already measured in HI by Fouqué et al. (1990) at V=1803 km s^-1 (confirmed). P13275 (Sc) is at the edge of the beam with V=1510 km s^-1 (Da Costa 1991), It is probably the faint signal detected on the left of the emission due to P13283.

P16863, HICK 33C: Distorted HI profile, confusion suspected. 4 objects in the beam: HICK 33A, 33B, 33C, and 33D, with V=7570 km s^-1, V=8006 km s^-1, V=7818 km s^-1, and V=7767 km s^-1 respectively. All are ellipticals except HICK 33C which is an Scd spiral.

P19861 and P19862: Galaxies aligned along the same meridian and separated by 9 arcmin in declination. They are both in the Nançay beam. However, it is the same profile which is detected when one or the other is in the center of the beam, though with a fainter signal when P19862 is sighted (see figure). It is consequently the emission of P19861 which is detected in both spectra, P19862 emission being too faint to disturb it. Already observed at 21-cm by Fouqué et al. (1990).

P20363: Observed at V=2604 km s^-1 (LEDA). P20367 also in the beam, but no known velocity. However, the assymetrical shape of the HI profile may be the sign of an HI confusion.

P21044, KCPG136A: Pair with P21045 (KCPG136B). KCPG136A is an Sc galaxy expected at V=9753 km s^-1, and KCPG136B is a Sb galaxy expected at V=9914 km s^-1 (Tift 1982). Most probable HI confusion, the 2 profiles are superimposed.

P21380, UGC 3922: Already measured in HI at V=8785 km s^-1 by Giovanelli et al. (1982). Distorted galaxy (warp), no close companion known. Atypical HI profile.

P21886, ESO 493-18: Already measured in HI at V=2658 km s^-1 by Kraan-Korteweg & Huchtmeier (1992). Profile disturbed, could be due to P21878 (Sab galaxy) which is at the edge of the beam.

P23537, NGC 2585: Sb galaxy, measured in OH at V=7193 km s^-1 (Baan et al. 1992). A signal is detected at $V\simeq6870$ km s^-1, but nothing is seen at the above expected velocity. The emission of NGC 2584 (Sbc, at the edge of the beam) could contribute to the low velocity peak at V $\simeq$ 6800 km s^-1, or perhaps to the total profile (optical velocity from Mathewson et al. 1992).

P23558, ESO 495-12: SAIT3407-2 and SAIT3412-2 (Sc galaxies) also in the beam, but probably far beyond P23558. No confusion expected.

P23697: IRAS galaxy with V=8984 km s^-1 from Strauss et al. (1992). P23696 close to the center of the beam, but no known velocity. The noisy shape of the HI profile could be the sign of an HI confusion.

P24889, UGC 4638: It is a disrupted spiral with a chaotic outer disc. In pair with MCG 0-23-6 (Irr galaxy); double system (ARP257): galaxies joint by a segment of thin arc. Radial velocities are respectively V=3340 km s^-1 (Tift 1982) and V=3318 km s^-1 (Karachentsev 1980). HI confusion expected.

P27468: Expected at V=2400 km s^-1 from Pietro et al. (1986), but nothing is detected at this velocity. The signal present in the spectrum is the contribution of ESO 373-12, which is at the edge of the beam (measured at V=2640 km s^-1 by Fouqué et al. 1990; HI measurement).

P27991, NGC 2993: Pair with NGC 2992 (ARP 245), galaxies in interaction, expected respectively at V=2420 km s^-1 (HI measurement, Richter & Huchtmeier 1987) and V=2314 km s^-1 (LEDA, HI measurements). The two corresponding emissions are well seen in the spectrum, but are not separable (see Richter & Huchtmeier 1987).

P28290, IC2513: IC2513 and IC2514 described as a single object in LEDA. However, the HI profile seems to indicate the presence of two different galaxies: one with a narrow profile at $V\simeq3000$ km s^-1, the other one around $V\simeq2800-2900$ km s^-1. (this point is also questionned in ESO catalogue).

P28388, M-1-25-50: Expected at V=6348 km s^-1 (LEDA). Strange profile, the right hand peak could be the object sighted. Possible HI-confusion with M-1-25-51 which is also in the beam (unknown velocity).

P29578: this object was probably sighted at a wrong velocity. The low velocity peak is certainly the emission from N3143 which is expected at V=3536 km s^-1 (Schweizer 1987). The second fainter peak is probably the contribution of N3145 which is a large Sbc galaxy located at the edge of the beam (V=3696 km s^-1, according to LEDA).

P29813, UGC 5514, KCPG227A: Pair with KCPG227B. Distorted HI profile: warp due to interactions or HI-contribution of the companion? V(227A) $\simeq$ 3635-3666 km s^-1 (Karachentsev 1980; Scodegio & Gavazzi 1993); and V(227B) $\simeq$3486-3709 km s^-1 (Karachentsev 1980; Tift 1982).

P30211: 4 objects in the beam: P30211 (V=3427 km s^-1, Fairall 1992), P30209 (V=3533 km s^-1, Fairall, 1992), P30208, and P30204 (V=3697 km s^-1, Davies et al. 1987). The left signal could be due to P30208 emission; The signal at $\simeq$3500 km s^-1 is the superimposition of P30211 and P30209 contributions.

P31885: Face-on galaxy. Also HI contribution due to P31875. However, its signal is most certainly the narrow peak at $V\simeq2950$ km s^-1. The emission line of P31875 has been successfully measured without confusion (see spectrum and Table) at V=3180 km s^-1.

P32059, UGC 5837: Expected at V=1689 km s^-1 (Chincarini & Rood 1972) or V=1918 km s^-1 (Sandage 1978). HI confusion due to P32081 (UGC 5841) with V=1883 km s^-1 (Haynes & Giovanelli 1991, HI-measurement).

P32495, NGC 3394: Measured in HI at V=3390 km s^-1 by Magri (1994). N3392 is also in the beam at $V\simeq3275$ km s^-1 (average, LEDA). Possible HI-confusion.

P32531: Expected at V=5253 km s^-1 (Fairall 1992). Disturbed HI-profile, probably due to contribution of P32573 at the edge of the beam (V=5476 km s^-1, HI-measurement from Bottinelli et al. 1993: the faint peak at $V\simeq5750$ km s^-1 could be its high velocity peak).

P33862, UGC 6207: Close paired galaxies (ARP301), in interaction with U6204. Confused HI- profile.

P34864: Triple system (Vorontsov-Velyaminov) with companions at 1.5' and 1.9'. Possible HI confusion.

P34874: Expected at V=2950 km s^-1 (LEDA). P34856 is in the beam at V=2737 km s^-1 (HI- measurement, Gallagher et al. 1995). HI confusion.

P35321, UGC 6472: 4 objects in the beam (ARP299, VV218): P35372, P35325, P35321 (V=3024 km s^-1, LEDA), P35326 (V=3090 km s^-1, LEDA). HI confusion.

P36889, NGC 3894: See P36907.

P36907, NGC 3895: P36889 (NGC 3894) appears in absorption in the center of N3895's emission line. This absorption line was directly measured by Gorkom et al. (1989) and Dickey (1986) at V=3230 km s^-1 and V=3256 km s^-1 respectively. The width of NGC 3895's emission line was correctly measured.

P37616, NGC 3994: 3 objects (ARP 313): NGC 3994 (Sc galaxy expected at V=3133 km s^-1, LEDA), NGC 3991 (Irr galaxy expected at V=3192 km s^-1, LEDA), and NGC 3995 (Sm galaxy expected at V=3250 km s^-1, LEDA). HI confusion.

P37969, NGC 4039: Paired galaxies (ARP 244) in interaction. Companion NGC 4038. HI confusion.

P38454: Pair with P38455 ($B_{\rm t}=15.7$ mag) according to NGC, also in the beam. The sighted galaxy P38454 is a Sb, face-on, with $B_{\rm t}=14.7$ mag, and should show a rather narrow HI line. UGC 7104 (Sb, $B_{\rm t}=15.1$ mag) is also in the beam. Probably HI confusion, given the shape of the signal detected.

P44959, HICK 63D: HICK 63A, 63B, and 63C are all in the beam at V=5238 km s^-1, 9346 km s^-1, and 9460 km s^-1 respectively (Hickson 1993). HICK 63D is expected at V=9141 km s^-1. The HI contributions of B and C components disturb strongly the measured profile.

P45000, UGC 8164: Sbc galaxy. UGC 8183 (Sb) in the off-beam of comparison: no velocity known, but approximately same magnitude as UGC 8164. It probably causes the negative signal which appears in the middle of UGC 8164's HI profile.

P46479, IC879: Expected at V=1979 km s^-1 (LEDA). In fact, we measured mainly the emission of NGC 5078 which is close to the beam, has a large apparent diameter ($\simeq$5 arcmin), and is expected at V=2168 km s^-1 according to Richter&Huchtmeier (1987). NGC 5078 has a wide double-horn HI profile (W₂₀=612 km s^-1), the 2 peaks being respectively at V=1950 km s^-1 and V=2450 km s^-1. The contribution of IC879 coul be the intermediate peak centered on V=2070 km s^-1.

P47161: P47140 also in the beam at about the same velocity. However, this is a SO galaxy whose poor HI content probably does not contribute to the detected signal of the much brighter, Sbc galaxy, P47161.

P48862, UGC 8713, VV317: Pair with UGC 8715 (face-on, Sd). Both signals identified in the HI spectrum and well separated. The profile of UGC 8715 appears asymmetrical because not in the center of the beam. No confusion.

P49489, NGC 5376: NGC 5379 (SO, V=1756 km s^-1, LEDA) and UGC 8859 (Irr, V=1610 km s^-1, LEDA) both at the edge of the beam. The contribution of UGC 8859 is seen at V=1600 km s^-1 (low velocity peak), and the emission of NGC 5376 is found as expected at $V\simeq 2050$ km s^-1 (see Table). No HI confusion: the contribution of NGC 5379 is probably negligible.

P49598, NGC 5378: NGC 5380 at the edge of the beam, probably contributes a little at the high velocity edge of the detected profile (cf. velocities listed in LEDA). Probably HI confusion.

P50183, UGC A 382: Scd galaxy. Profile certainly disturbed by close face-on companion UGC A 383 (Scd) also in the beam.

P52839, NGC 5757: Profile strongly disturbed by P52846 (1.9' W, 3.2' N). Its HI signal should be the narrow low velocity peak centered on V=2550 km s^-1. See below comments on P52846.

P52846: Edge-on Sc galaxy. HI profile could be slightly disturbed by P52839 emission, which is much fainter. Its 2 peaks at V=2650 km s^-1 and 2800 km s^-1 (32 and 21 mJy respectively) are found fainter when the beam is centered on the companion P52839 (see above).

P53995, NGC 5857: Pair with NGC 5859 also in the beam. Both have similar type, magnitude and velocity. The HI profile is consequently confused.

P55070: HI confusion possible with P55082: probably in pair (interaction?) at approximately the same velocity; both have been observed separately, the two corresponding beams appearing well separated on the sky. However, each galaxy could contribute partly to the profile of its counterpart.

P55082: The low velocity peak could reflect a contribution from P55070.

P55080: Close pair in interaction (ARP90, VV823). The emission of the companion P55076 is superimposed.

P55410: Sa galaxy. Atypical profile with two peaks clearly separated. Confusion suspected, but not confirmed (see comments on P55426).

P55426: Face-on galaxy, type unknown, velocity unknown. Should have a narrow profile as expected from its inclination: what we detected is certainly the emission of P55410 which is a edge-on Sa galaxy (cf. comment above and spectra).

P57125, UGC 10197: Paired galaxies (VV327). Companion is the Sd galaxy P57124 (U10198). Both are in the center of the beam. P57125 expected around V=4600 km s^-1 (optical measurements: Chincarini & Martins 1975; Tarenghi et al. 1979). The central peak could be the superimposition of the two profiles, one being slightly shifted with respect to the other one.

P57173: Atypical profile for a single object. Also VV624: "3 members or an ellipse or a ring edge-on?". Nilson catalogue: "very large nucleous bulge with a faint halo similar to M104?"

P57312, ESO 451-11: 3 Sc galaxies in the beam (ESO $\rm 451-G11$ group): ESO 451-11, ESO 451- 12, ESO 451-14. The second with V=4298 km s^-1 (LEDA, optical measurements) contributes to the observed profile and is probably responsible for the main (high velocity) peak. See also comments on P57331.

P57331, ESO 451-14: In group ESO 451-G11 (see comment on P57312). What is measured is certainly the contribution of ESO 451-12, which is also in the beam.

P57984, NGC 6142: Sc galaxy, expected at V=10151 km s^-1 (LEDA, optical measurements) with a wide profile (edge-on), which should correspond to the total observed width. P57979 also in the beam (face-on, Sc) at V=10046 km s^-1 (Huchra et al. 1995) and certainly contributes to the HI profile. Given as pair in NGC .

P59077, NGC 6246: Sc galaxy with companion at 2.6' (late SB galaxy). P59090 (NGC 6246A) at 9.8' also at the edge of the beam: Sc galaxy, face-on, that probably also contributes to the observed signal (one of the peaks). From Oosterloo (1993), V(P59077)=5334 km s^-1 and V(P59090)=5260 km s^-1; then P59077 should correspond to the total width, and P59090 to the signal defined by the two low velocity peaks at V=5115 and 5405 km s^-1.

P59251, VV289: Sa galaxy, edge-on. Pair with UGC 10610. Two objects expected respectively at V=9900 km s^-1 and V=9780 km s^-1 respectively (Bushouse 1986). Wide HI profile expected for P59251, but not detected.

P61161, UGC 11055: Sb galaxy expected at $V\simeq2950$ km s^-1 (LEDA). Given as pair in UGC with Scd galaxy P61165 (UGC 11057) also in the beam at $V\simeq2860$ km s^-1 (LEDA). HI confusion expected.

P61558, UGC 11152: Sdm, pair with P61568 (Zwicky catalogue). P61558 expected at $V\simeq2730$ km s^-1 (LEDA, HI-measurement). Atypical profile which could reflect a contribution of the companion.

P64939, NGC 6926, VV 621: Sbc, pair with NGC 6929 (SO) which could disturb the signal. However, the atypical shape of the profile could rather be due to intrinsic pattern: "very bright patchy arc tends to disrupt the spiral pattern" (from UGC ).

P65625, HICK 88B: Triple system HICK 88A (Sb), HICK 88B (Sa), and HICK 88C (Sbc). All are in the beam at respectively V=6033, 6010, 6083 km s^-1 (Hickson 1993). The 3 HI contributions are superimposed.

P68292, IC5174: Sb galaxy. Two other galaxies in the beam: IC5175 (Sab) and Leda122359 at V=10724 km s^-1 (LEDA) and V=11029 km s^-1 (Schectman 1996). IC 5174 expected at V=11125 km s^-1 (LEDA). Probably HI confusion.

P68880: P68981 is in the off-beam of comparison and appears with negative flux in the spectrum at V=6150 km s^-1. However, the edges of the HI profile of P68880 are not disturbed, and the line width is unambiguously measurable.

P68953, NGC 7285: Pair with NGC 7284 (ARP93, VV74). V=4272 and 4527 km s^-1 respectively (LEDA). Each main peak well corresponds to the above expected values.

P71155, UGC 12535: Sbc, edge-on galaxy, expected at V=4214 km s^-1 (RC3, optical measurement). P71159 also in the beam (type unknown); its HI signal at V=3886 km s^-1 (Bothun et al. 1985, HI measurement) is well seen in our spectrum. There may be also an HI contribution of NGC 7631 at V=3754 km s^-1 (LEDA, HI measurement).

P71209, UGC 12548: Sa edge-on galaxy expected at V=4951 km s^-1 (Karachentsev 1980, optical measurement). UGC 12547 also contributes to the observed HI profile at V=5029 km s^-1 (Karachentsev 1980, optical measurement). Also P71224 at the edge of the beam, but no known type or velocity.

P71634, IC 1496: Expected at V=5162 km s^-1 (Huchra et al. 1993). IC 1492 close to the beam, with approximately same velocity (V=5287 km s^-1, Huchra et al. 1993). The two peaks could be the separate narrow lines of these two face-on galaxies.

P72430: Signal at the limit of detection ($S/N\simeq1.7$). No confident line edges.

P72985: Sc galaxy, expected at V=6806 (Huchra et al. 1993). P72987 (Sb) also in the center of the beam at V=6635 (Huchra et al. 1993). the two profiles are superimposed with a shift of about 200 km s^-1 between.

P72987: see P72985.