Central Elliptical Galaxy Research Articles

The abundance distribution and luminosity function of globular clusters in NGC 1399

view Abstract Citations (91) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Abundance Distribution and Luminosity Function of Globular Clusters in NGC 1399 Geisler, Doug ; Forte, Juan Carlos Abstract Integrated Washington photometry has been obtained for the globular cluster system of NGC 1399, the central elliptical galaxy in the Fornax cluster. A new integrated metallicity index, C - T_1_, is defined which is about 3 times more sensitive to metal abundance than the previous such Washington index. Abundances accurate to 0.3 dex are derived for ~ 150 of the brightest globular clusters. The clusters have a broad, flattened abundance distribution, with a mean metallicity of [Fe/H] = -0.85 +/- 0.1, 0.75 dex more metal-poor than the halo. A significant fraction of the clusters have an approximately solar abundance, while virtually no clusters exist with [Fe/H] < -2. The luminosity function is also determined for ~ 600 clusters to a limiting magnitude of T_1_ ~ 23.75 (50% completeness limit). The luminosity function clearly shows a turnover at T_1_ = 23.0 +/- 0.15 or V = 23.45 +/- 0.16. Matching this luminosity function with that for the globular cluster system of the Galaxy and M87 yields a distance modulus of 31.0 +/- 0.25 for Fornax, 0.5 +/- 0.2 mag closer than Virgo. A Hubble constant of 66 +/- 14 km s^-1^ Mpc^-1^ is derived assuming a canonical value for the Local Group Virgocentric infall velocity. Alternatively, solving for this infall velocity gives a value of 236 km s^-1^. Publication: The Astrophysical Journal Pub Date: February 1990 DOI: 10.1086/185654 Bibcode: 1990ApJ...350L...5G Keywords: Abundance; Elliptical Galaxies; Globular Clusters; Luminosity; Astronomical Photometry; Galactic Clusters; Late Stars; Metallicity; Astrophysics; ABUNDANCES; CLUSTERS: GLOBULAR; LUMINOSITY FUNCTION; GALAXIES: ABUNDANCES; GALAXIES: DISTANCES full text sources ADS | data products SIMBAD (3) NED (1)

NUCLEI OF NORMAL GALAXIES.

ABSTRACT The author reviews recent research on the environment in which active nuclei reside, namely the dense stellar populations found in the centers of elliptical galaxies and spiral bulges. He discusses new developments concerning the structure and dynamics of nuclei, recent results on the age and chemical composition of nuclear populations, the possibility that important changes in the initial mass function occur in nuclei, limits which can be placed on recent star formation in old populations, and the detection of "submerged" active nuclei in outwardly normal galaxies. Emphasis is placed on problems for which space astronomy experiments are well suited.

Optical and radio observations for the BL Lacertae objects 1219 + 28, 0851 + 202, and 1400 + 162

Radio- and visible-wavelength observations for the BL Lac object 1219 + 28 (ON 231, W Com) are reported along with optical observations of 0851 + 202 (OJ 287), and radio data for 1400 + 162 (4C 16.39, OQ 100). The obtained data consist of imaging and surface photometry for both 1219 + 28 and 0851 + 202, as well as spectra for 1219 + 28, and Very Long Baseline Interferometry (VLBI) observations for 1219 + 28 and 1400 + 162. Two emission features have been observed in the spectrum of 1219 + 28. Radio observations of 1219 + 28 in three frequencies reveal the presence of a radio jet with at least three components. The obtained results for 1219 + 28 support previous conclusions that at least some BL Lac objects are located at the center of elliptical galaxies.

DIRECT ELECTRONOGRAPHIC OBSERVATIONS OF THE NEBULOSITY AROUND 3C 120

ABSTRACT Direct electronographic observations of 3C 120 with a Spectracon image converter mounted at the prime focus of the 120-inch reflector show that the bright, semistellar source is situated at the center of a smooth, elliptical nebulosity whose outer dimensions, at the level of 1.0% of sky, are 44" X 63", and whose mean color index is (B- V) = +0.85 0.15. These observations are consistent with the interpretation of N-type systems as quasi-stellar objects located at the center of elliptical galaxies. Key words: quasi-stellar objects - radio sources - N-type galaxies