We present VLT spectroscopic observations with different spectral resolutions and different slit orientations of the two metal-deficient blue compact dwarf ( BCD ) galaxies Tol 1214–277 and Tol 65 .
The oxygen abundances in the brightest H ii regions of Tol 1214–277 and Tol 65 are found to be 12 + log O/H = 7.55 \pm 0.01 and 7.54 \pm 0.01 , or Z _ { \odot } /24 12+log ( O/H ) _ { \odot } = 8.92 ( Anders & Grevesse [ 1989 ] ) . .
The nitrogen-to-oxygen abundance ratios in the two galaxies are log N/O = –1.64 \pm 0.03 and –1.60 \pm 0.02 and lie in the narrow range found for other most metal-deficient BCDs .
The helium mass fraction derived in several H ii regions in both galaxies is consistent with a high primordial helium mass fraction , Y _ { p } \sim 0.244 .
We confirm the detection of the high-ionization forbidden emission line [ Fe v ] \lambda 4227 in the spectrum of Tol 1214–277 .
Additionally , weak [ Ne iv ] \lambda 4725 , [ Fe vi ] \lambda 5146 , \lambda 5177 , and [ Fe vii ] \lambda 5721 , \lambda 6087 emission lines are detected in the high-resolution spectrum of Tol 1214–277 .
The detection of these lines implies the presence of hard radiation with photon energy in the range \sim 4 – 8 Ryd .
Emission lines are detected in the spectra of eight galaxies in the fields of Tol 1214–277 and Tol 65 .
Seven of these galaxies are background objects , while one galaxy has a redshift close to that of Tol 1214–277 .
Situated at a projected distance of \sim 14.5 kpc from Tol 1214–277 , this galaxy is probably a companion of the BCD . Tables 2 , 3 , 4 and 8 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr ( 130.79.128.5 ) or via http : //cdsweb.u-strasbg.fr/cgi-bin/qcat ? J/A+A/