Bc. Whitmore et al., HUBBLE-SPACE-TELESCOPE DISCOVERY OF CANDIDATE YOUNG GLOBULAR-CLUSTERSIN THE MERGER REMNANT NGC-7252, The Astronomical journal, 106(4), 1993, pp. 1354-1370
New, high-resolution images of the central region of NGC 7252 obtained
with the Planetary Camera of the Hubble Space Telescope are presented
. NGC 7252 (sometimes referred to as the ''Atoms-for-Peace'' Galaxy) i
s a prototypical example of a remnant of two merged disk galaxies. Our
most striking result is the discovery of a population of about 40 blu
e pointlike objects in this galaxy. The mean absolute magnitude of the
se objects is M(V) = -13 mag; the mean color is V-I=0.7 mag; and the m
ean effective radius is 10 pc (for H-1 = 50 km s-1 Mpc-1). The luminos
ities, colors, projected spatial distribution, and sizes are all compa
tible with the hypothesis that these objects formed within the last 1
Gyr following the collision of two spiral galaxies, and that they are
young globular clusters. It therefore appears that the number of globu
lar clusters may increase during the merger of gas-rich galaxies. This
weakens van den Bergh's objection against ellipticals being formed th
rough disk mergers, based mainly on the fact that disk galaxies have f
ewer globular clusters per unit luminosity than ellipticals do. Other
findings are: (1) NGC 7252 shows a single, semistellar nucleus; (2) re
latively bright spiral structure is seen within 3''.5 (1.6 kpc) of the
center, presumably formed through the continued infall of gas into a
disk around the center of the galaxy; (3) dust lanes and very weak spi
ral structure are seen out to about 9'' (4.2 kpc), primarily on the NE
side; and (4) a ripple is found on the west side, 5''.0 from the cent
er.