NGC 3987. This edge-on galaxy has a prominent dust lane in the optical. Though
the submm emission follows the dust lane it is seen slightly offset. A similar
result was found for another edge-on spiral by Stevens et al. (2005), who
conclude this effect is simply an effect of the inclination of the galaxy on the
UGC 6928: No H I in AGC archive; use Bottinelli et al. (1990; lesser
quality than reprocessing of archive data).
NGC 3987: Our H I velocity is about 50 km s^-1^ lower than the 4 reported
Arecibo values, and all profiles have very large widths. The mean values
for the Arecibo spectra of NGC 3987 are V_HI_ = 4500 km s^-1^,
W_20_ = 569 km s^-1^ and I_HI_ = 7.1 Jy km s^-1^. A possible source of
confusion is the B_T_ 15.8 mag Sbc spiral NGC 3989, at an E-W distance of
1.2' from NGC 3987. NGC 3989 has no published optical redshift. The
Arecibo H I profile parameters for NGC 3989 of Mould et al. (1993) and
Scodeggio et al. (1993 - where NGC 3987 is referred to as NGC 3997) are
comparable (average V_HI_ = 4623 km s^-1^, W_20_ = 519 km s^-1^ and
I_HI_ = 3.2 Jy km s^-1^), while the Arecibo profile of Williams (1986)
has a 90 km s^-1^ higher central velocity (4713 km s^-1^), less flux
(2.0 Jy km s^-1^) and a considerably smaller width (W_20_ = 374 km s^-1^).
Confusion between the Arecibo profiles of NGC 3987 and 3989 is in
principle possible, as their projected separation is 2.6'; in fact, the
spectrum of Scodeggio et al. has a complex structure, indicative of
confusion or interaction. On the other hand, the H I emission observed at
Arecibo towards NGC 3989 cannot explain the H I observed at Nancay towards
NGC 3987 below the low-velocity edge of the Arecibo profile of NGC 3987.
In conclusion, the H I distribution appears complex and extended tidal
debris may be present in H I.
UGC 06935 at 4.6, 55
11 54.8 +25 30 = NGC 3989 at 2.6, 30, 0.7 x 0.3, m=15.7
In multiple system with NGC 3989, NGC 3993 and NGC 3997.