62 citations · 348 across the 21 of their papers we have counts for
18 papers · 1 filter
Tests of Chemical Enrichment Scenarios in Ellipticals Using Continuum Colors and Spectroscopy
J. Schombert, K. Rakos
We combine spectroscopic metallicity values with integrated narrowband continuum colors to explore the internal metallicity distribution in early-type galaxies. The different techn…
The Age of Cluster Galaxies from Continuum Colors
K. Rakos, J. Schombert, A. Odell
We determine the age of 1,104 early-type galaxies in eight rich clusters ( to ) using a new continuum color technique. We find that galaxies in clusters divide i…
Age and Metallicities of Cluster Galaxies: A1185 and Coma
K. Rakos, J. Schombert, A. Odell
We present age and metallicities determinations based on narrow band continuum colors for the galaxies in the rich clusters A1185 and Coma. Using a new technique to extract luminos…
The Rest-frame Optical Colors of 99,000 SDSS Galaxies
V. Smolcic, Z. Ivezic, M. Gacesa +17
We synthesize the rest-frame Stroemgren colors using SDSS spectra for 99,088 galaxies selected from Data Release 1. This narrow-band ~200 AA photometric system (uz, vz, bz, yz), fi…
Cluster Populations in Abell 2125 and 2218
K. Rakos, J. Schombert
We combine new narrow band photometry with archival WFPC2 data for A2218 (=0.18) and A2125 (=0.25), two clusters with intermediate redshifts but very different cluster proper…
Age and Metallicity Estimations in Old Stellar Populations from Stromgren Photometry
K. Rakos, J. Schombert, A. Odell
We present a new technique to determine age and metallicity of old stellar populations (globular clusters and elliptical galaxies) using an iterative principal component analysis o…
Age and Metallicity Estimation of Globular Clusters from Stromgren Photometry
K. Rakos, J. Schombert
We present a new technique for the determination of age and metallicity in composite stellar populations using Stromgren filters. Using principal component (PC) analysis on multi-c…
The Ages of Dwarf Ellipticals
K. Rakos, J. Schombert
We present narrow band photometry of 91 dwarf ellipticals in the Coma and Fornax clusters taken through the Stromgren (uvby) filter system. Dividing the sample by dwarf morphology…
Narrow Band Continuum Colors of Distant Cluster Populations
J. Schombert, K. Rakos
In this poster, we present new results on narrow band photometry for A2218 (=0.18) and A2125 (=0.25), two clusters with similar redshifts, but very different cluster properti…
Global Metallicities From Globulars Through To Elliptical Galaxies
K. Rakos, J. Schombert, A. Odell
We present narrow band data on dwarf ellipticals in nearby (Virgo, Fornax) and intermediate redshift clusters (A2125, A2218) in order to study their mean age and metallicities. In…
Stroemgren uvby photometry of the open clusters NGC 6192 and NGC 6451
E. Paunzen, H. M. Maitzen, K. D. Rakos +1
We have investigated the two open clusters NGC 6192 and NGC 6451 for which widely different reddening values and thus ages and distances can be found in the literature via Stroemgr…
The Color-Magnitude Relation in Coma: Clues to the Age and Metallicity of Cluster Populations
A. Odell, J. Schombert, K. Rakos
We have observed three fields of the Coma cluster of galaxies with a narrow band (modified Stromgren) filter system. Observed galaxies include 31 in the vicinity of NGC 4889, 48 ne…
Ages and Metallicities of Fornax Dwarf Ellipticals
K. Rakos, J. Schombert, H. M. Maitzen +2
Narrow band photometry is presented on 27 dwarf ellipticals in the Fornax cluster. Calibrated with Galactic globular cluster data and spectrophotometric population models, the colo…
Stromgren Photometry from z=0 to z~1. The Method
Susanna Steindling, Noah Brosch, Karl Rakos
We use rest-frame Stromgren photometry to observe clusters of galaxies in a self-consistent manner from z=0 to z=0.8. Stromgren photometry of galaxies is an efficient compromise be…
Cluster Populations in A115 and A2283
Karl D. Rakos, James M. Schombert, Andrew P. Odell +1
This paper presents four color narrow-band photometry of clusters A115 () and A2283 () in order to follow the star formation history of various galaxy types. Alth…
The Butcher-Oemler Effect in Abell 2317
Karl D. Rakos, Andrew P. Odell, James M. Schombert
This paper presents deep narrow band photometry of the cluster A2317 (z=0.211) carried out using KPNO 4 m and Steward 2.3 m telescopes. Using rest frame Stromgren photometry, it is…
Color Evolution from z=0 to z=1
Karl Rakos, James Schombert
Rest frame Stromgren photometry (3500A, 4100A, 4750A and 5500A) is presented for 509 galaxies in 17 rich clusters between z=0 and z=1 as a test of color evolution. Our observations…
Photometric Signatures of Starbursts in Interacting Galaxies and the Butcher-Oemler Effect
Karl Rakos, Thomas Maindl, James Schombert
This paper presents new and synthetic narrow band photometry of ellipticals, spirals, Seyferts and interacting galaxies in an attempt to identify the cause of the unusually high fr…