DETECTION OF THE GLOBULAR-CLUSTER POPULATION AROUND NGC 7814

Abstract

ABSTRACT We report the statistical detection of 120 ± 25 globular clusters in fields surrounding the edge-on S03 galaxy NGC 7814. Counts of objects are made to V = 24.5 and reach at least the peak of the globular cluster luminosity function (GCLF). The bulge of NGC 7814 is of moderate luminosity and is highly flatteend with an axial ratio of b/a==0.48. Counts made for 0.5' - 5.0' radius in concentric rings of width 0.5' show a clear detection of excess objects relative to the background in each annulus. Correcting for incompleteness in both magnitude and areal coverage yields a total cluster population of 498 ± 164 within this region. We are thus confident that we have a strong detection of the globular cluster system (GCS) of NGC 7814. Accounting for the presence of clusters that we could not detect in the inner few kpc and those that might lie outside our survey area would likely increase the total population by a factor of two. At our assumed distance of (m-M)=30.48, the specific frequency (S) of globulars is 7.6 ± 3.2. The intrinsic GCLF for NGC 7814 is very poorly determined from these data but may indicate a distance one magnitude further away, in which case S would be 5.2 ± 2.2. These values of S are typical for elliptical galaxies but are rather high compared to those of spirals. The radial distribution of globular cluster candidates does not fall off as fast as the halo light. Excess counts in a field are not centered on the minor axis and can only be reconciled with the rest of the data if the GCS of NGC 7814 is highly flattened.