2. Targets and observations

Table 1 (click here) provides the list of targets considered in this catalogue. It includes the central galaxy's name, reference coordinates, morphological type, heliocentric velocity and size. The column "field size'' is the projected size of the field of view (of ) at the distance of the central galaxy, calculated using . The positions of the central galaxies' nuclei were used as the reference positions for the identifications presented in the main part of the catalogue. For these reference positions, we used published coordinates of the central galaxies' nucleus (taken from NED), if they agreed well with our determination of the geometric center of the Central Galaxy (using astrometry based on the Hubble-GSC), otherwise we re-determined the reference coordinates; see the notes to Table 1 (click here).

 

Galaxy morph.type velocity Galaxy Size Field Size

name h:mm:s km/s arcmin² Kpc²

NGC 520 01:24:35 3:47:37⁽⁴⁾ S pec 2266 9200 (ARP157:VV231c)

NGC 772 01:59:20 19:00:28⁽²⁾ SA(s)b 2472 11000 (ARP78)

NGC 1023 02:40:24 39:03:46⁽¹⁾ SB(rs)0 637 730 (ARP135)

NGC1253 03:14:09 -02:49:22⁽¹⁾ SB(s)m 1831 6030 (ARP279)

ARP 141 07:14:21 73:28:36⁽⁶⁾ E 2735 - 13400

NGC2535/6 08:11:15 25:11:36⁽⁵⁾ SB(rs)c pec 4142 30800 (ARP 82)

NGC 2623 08:38:24 25:45:17⁽¹⁾ - 5535 - 55000 (ARP243)

NGC2782 09:14:05 40:06:49⁽¹⁾ SAB(rs)a pec 2562 11800 (ARP 215)

NGC 3226/7 10:23:29 19:52:54⁽³⁾ E2:pec 1151 2380 (ARP94)

NGC 3656 11:23:38 53:50:31⁽¹⁾ (R)I0:pec 2860 14700 (ARP155)

NGC 3690 11:28:31.9 58:33:45⁽¹⁾ SBm pec 3132 17600 (ARP299)

NGC 3921 11:51:06.6 55:04:45⁽¹⁾ (R)SA(s)0/a pec 5838 61300 (ARP224)

Notes to Table: Source for reference coordinates: ⁽¹⁾ position taken from NED; ⁽²⁾ position measured on CCD frame; ⁽³⁾ position measured on CCD, midway between NGC 3226 and NGC 3227; ⁽⁴⁾ position listed for VV231c in NED (positions of other identifications do not correspond well with the geometric center); ⁽⁵⁾ position listed for Arp82 in NED (is midway between NGC 2535 and NGC 2536); ⁽⁶⁾ position measured on CCD, midway between the two major nuclei of Arp 141.

Images of the galaxies were taken on 1.-3. December 1992, using the 2.5 m Isaac Newton Telescope at the Observatorio del Roque de los Muchachos (ORM), La Palma. The observations were done with the EEV5 CCD-camera attached to the prime focus of the telescope, with an effective field of arcmin² and 0.55 arcsec/pixel spatial resolution. Observations were taken in grey-bright time, which restricted the limiting magnitudes. The atmospheric transparency conditions were very good and seeing ranged from 0.9 to 1.5 arcsec. Images were taken with V and R filters; the exposure times are given in Table 2 (click here). In order to allow positional calibrations of the fields, images with short (20 s) exposures were also taken, where the bright stars are not saturated. For photometric calibration, Landolt (1992) standards were observed at a range of airmasses.

Raw images were zero-subtracted and flatfielded in the usual manner. A "standard" flatfield was obtained by averaging the individual sky-flats taken at the entire observing run. This was possible, since the stability of the flats between nights was better than 1%.

 

Galaxy exp.time field-size N(EO) N(SO)

measured expected measured expected

sec arcsec mag

NGC 520 300, 600 (0.70, 0.65) 20.0 3.3 85, 45 150, 70 45

NGC 772 300, 500s (0.75, 0.70) 20.5 2.9 119, 84 209, 98 69

NGC 1023 200, 300 (0.70, 0.60) 19: 3.0 21, 9 487, 191 157

NGC 1253 300, 600 (0.70, 0.60) 19: 2.7 44, 7 111, 33 28

ARP 141 500, 600 (0.70, 0.65) 20.5 3.2 183, 76 623, 301 140

NGC 2535/6 300, 1000 (0.60, 0.55) 20.5 3.2 120, 48 373, 160 129

NGC 2623 600, 500 (0.70, 0.65) 20.0 3.3 113, 37 368, 95 81

NGC 2782 600, 600 (0.75, 0.70) 20.5 3.1 93, 33 274, 110 62

NGC 3226/7 600, 600 (0.60, 0.60) 20.5 3.1 156, 63 260, 91 50

NGC 3656 600, 600 (0.60, 0.55) 20.5 3.2 257, 76 510, 72 48

NGC 3690 200, - (0.55, 0.50) 20.5 3.2 116, 81 181, 76 50

NGC 3921 200, - (0.60, 0.50) 20.0 3.3 137, 98 146, 56 42