Details

Autor(en) / Beteiligte

• Whitmore, Bradley C.
• Schweizer, Francois
• Leitherer, Claus
• Borne, Kirk
• Robert, Carmelle

Titel

Hubble Space Telescope discovery of candidate young globular clusters in the merger remnant NGC 7252

Ist Teil von

• The Astronomical journal, 1993-10, Vol.106 (4), p.1354-1370

Ort / Verlag

Legacy CDMS: University of Chicago Press

Erscheinungsjahr

1993

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• New, high-resolution images of the central region of NGC 7252 obtained with the Planetary Camera of the HST are presented. NGC 7252 is a prototypical example of a remnant of two merged disk galaxies. Our most striking result is the discovery of a population of about 40 blue pointlike objects in this galaxy. The mean absolute magnitude of these objects is Mv = -13 mag; the mean color is V-I = 0.7 mag; and the mean effective radius is 10 pc. The luminosities, colors, projected spatial distribution, and sizes are all compatible 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 globular clusters may increase during the merger of gas-rich galaxies. This weakens van den Bergh's objection against ellipticals being formed through disk mergers, based mainly on the fact that disk galaxies have fewer globular clusters per unit luminosity than ellipticals do. NGC 7252 shows a single, semistellar nucleus; relatively bright spiral structure is seen within 1.6 kpc of the center, presumably formed through the continued infall of gas into a disk around the center of the galaxy.