2. The sample

In the following, we describe the results obtained on a sample of BCDGs selected from the two Surveys conducted at Byurakan Observatory:

• the First Byurakan Survey (FBS) or Markaryan survey (Markaryan 1967 and following papers), on which thoroughly complete information is given by Mazzarella & Balzano (1986),
• the Second Byurakan Survey (SBS) (Markaryan & Stepanian 1983, and following papers) which spans a restricted area in the Northern Hemisphere but is 2 magnitude deeper than the FBS in the average.

Both surveys use a color criterion (the ultraviolet excess in the continuum) to select active galaxies. Most low-redshift, moderate or faint luminosity objects present in the FBS and the SBS exhibit an HII-like, narrow emission line spectrum. The presence of emission lines is a direct indicator of formation of massive ionizing stars, while the continuum ultraviolet excess is the signature of an integrated population containing a rich main-sequence of intermediate mass stars of B-A-F spectral types.

Our main interests lying in low-luminosity objects, we have selected BCDGs of low redshifts (typically lower than a recession velocity of ) with estimates of absolute magnitude . At the distances implied by these small recession velocities, we could keep a sufficient image size even on small linear diameter objects and retrieve physically significant data from the surface photometry even with 1 arcsec seeing conditions. All the selected objects have been previously observed spectroscopically at low spectral resolution (Stepanian, private communication for SBS objects, and numerous other sources, see Mazzarella & Balzano 1986) and have an HII-like emission line spectrum. Finally, objects with small angular size for the given redshift (typically 10 to 50'') have been preferred in order to bias deliberately the sample towards dwarf "compact'' galaxies.

Table 2 (click here) lists the observed objects and is self-explanatory. The apparent magnitudes are photographic estimates from the Byurakan surveys. Note that some objects present in Table 2 (click here) are still unpublished (Stepanian, private communication).

 

Object name z mag. app. Obs. period/ Telescope photom. cond.

SBS 0136+328 01 36 21.4 32 51 50 0.0211 18. Asiago Nov. 92 * fair

SBS 0940+544C 09 40 50.9 54 25 20 0.0057 18. TBL March 93** good

SBS 1006+578 10 06 11.9 57 48 42 0.0045 17. TBL Feb. 94 ** v. good

SBS 1054+504 10 54 02.5 50 24 19 0.0046 16.5 TBL Feb. 94 ** v. good

SBS 1147+520 11 47 16.4 52 00 51 0.0036 16.5 TBL March 93 ** good

SBS 1331+493 13 31 20.3 49 21 35 0.0024 15. Asiago March 94 * fair

SBS 1413+495 14 13 18.8 49 34 24 0.0024 16. Asiago March 94 * fair

SBS 1428+457 14 28 19.2 45 45 54 0.0078 16. TBL March 93 ** good

SBS 1533+574 15 33 03.5 57 27 02 0.0107 17.5 TBL March 93 ** good

MRK 324 23 26 32 18 15 58 0.0054 15.6 Asiago Aug. 92 * poor

MRK 900 21 29 59.5 02 24 51 0.0038 14.3 Asiago Aug. 92 * poor

MRK 996 01 27 35.4 -06 19 36 0.0054 15.5 Asiago Oct. 92 * not photometric(R)

MRK 1131 23 28 01.1 -02 09 53 0.0065 16. Asiago Oct. 92 * not photometric (B and R)

MRK 1308 11 54 12.2 00 08 11 0.0035 13.7 TBL Feb. 94 ** v. good

MRK 1416 09 20 55.9 52 34 08 0.0072 17. TBL March 93/Feb. 94 ** good/v. good

MRK 1418 09 40 27.2 48 20 13 0.0015 13.5 TBL Dec. 92 ** good

MRK 1423 09 43 01.7 58 58 24 0.0037 15.1 TBL Dec. 92 ** good

MRK 1426 09 49 18.4 48 33 49 0.0062 16.5 TBL March 93 ** good

MRK 1434 10 34 10 58 03 50 0.0068 16.5 TBL March 93 ** good

MRK 1450 11 38 35.6 57 52 27 0.0029 16. TBL March 93 ** good

MRK 1480 13 42 51.7 52 42 31 0.0058 16.5 TBL March 93/Feb. 94 ** good/v. good

MRK 1481 13 42 59.3 52 41 18 0.0060 17. TBL Feb. 94 ** v. good

MRK 1499 16 35 21.1 52 12 53 0.0087 15.6 TBL March 93 ** good

(*): Asiago: 1.82 m Telescope, Cima Ekar.
(**): TBL: Pic du Midi, 2 m Bernard Lyot Telescope.