Mármol-Queraltó, E., Cardiel, N., Sánchez-Blázquez, P., Trager, S. C., Peletier, R. F., Kuntschner, H., ...
The study of stellar populations in early-type galaxies in different environments is a powerful tool for constraining their star formation histories. This study has been traditionally restricted to...
RR Lyrae Variables in Two Fields in the Spheroid of M31 (2009)
Sarajedini, Ata, Mancone, Conor L., Lauer, Tod R., Dressler, Alan, Freedman, Wendy, Trager, S. C., ...
We present Hubble Space Telescope observations taken with the Advanced Camera for Surveys Wide Field Channel of two fields near M32—between 4 and 6 kpc from the center of M31. The data cover a time...
RR Lyrae Variables in Two Fields in the Spheroid of M31 (2009)
Sarajedini, Ata, Mancone, Conor L., Lauer, Tod R., Dressler, Alan, Freedman, Wendy, Trager, S. C., ...
We present Hubble Space Telescope observations taken with the Advanced Camera for Surveys Wide Field Channel of two fields near M32 - between four and six kpc from the center of M31. The data cover a...
ESO 381-47, an early-type galaxy with extended HI and a star forming ring (2009)
Donovan, Jennifer L., Serra, Paolo, Van Gorkom, J. H., Trager, S. C., Oosterloo, Tom, Hibbard, J. E., ...
ESO 381-47 is an early type galaxy with an extended HI disk. GALEX and very deep optical images reveal a distinct stellar ring far outside the optical body with a diameter of ~30 kpc, which has...
Trager, S. C., Somerville, R. S.
Stellar population parameters derived from spectral line-strengths provide a powerful probe of galaxy properties and formation histories. We implement the machinery for extracting...
Worthey, G., Dotter, A., Chaboyer, B., Jevremovic, D., Baron, E., ...
The first paper in this series explored the effects of altering the chemical mixture of the stellar population on an element by element basis on stellar evolutionary tracks and isochrones to the end...
The stellar population histories of early-type galaxies. III. The Coma Cluster (2008)
Trager, S. C., Faber, S. M., Dressler, Alan
We present stellar population parameters of twelve early-type galaxies (ETGs) in the Coma Cluster based on spectra obtained using the Low Resolution Imaging Spectrograph on the Keck II Telescope. Our...
Stellar abundances of early-type galaxies (2006)
It is currently impossible to determine the abundances of stellar populations star-by-star in dense stellar systems more distant than a few megaparsecs. Therefore, methods to analyse the composite...
IC 4200: a gas-rich early-type galaxy formed via a major merger (2006)
Serra, P., Trager, S. C., Van Der Hulst, J. M., Oosterloo, T. A., Morganti, R.
We present the result of radio and optical observations of the S0 galaxy IC 4200. We find that the galaxy hosts 8.5 billion solar masses of HI rotating on a ~90 deg warped disk extended out to 60 kpc...
The very late-stage merger IC 4200:pre-elliptical or pre-spiral? (2005)
Serra, P., Trager, S. C., Van Der Hulst, J. M., Oosterloo, T. A., Morganti, R., Van Gorkom, J. H.
Recent observations have revealed a class of unusually HI-rich early-type galaxies. By combining observations of their morphology, stellar populations and neutral hydrogen we aim to understand how...
Hot Stars in Old Stellar Populations: A Continuing Need for Intermediate Ages (2005)
Trager, S. C., Worthey, Guy, Faber, S. M., Dressler, Alan
We investigate the effect of a small contamination of hot, old, metal-poor starlight on the inferred stellar populations of early-type galaxies in the core of the Coma Cluster. We find that the...
Abundances from the Integrated Light of Globular Clusters and Galaxies (2003)
It is currently impossible to determine the abundances and ages of the stellar populations of distant, dense stellar systems star by star. Therefore, methods to analyze the composite light of stellar...
Determination of the Dark Matter Profile of Abell 2199 from Integrated Starlight (2002)
Kelson, Daniel D., Zabludoff, Ann I., Williams, K. A., Trager, S. C., Mulchaey, J. S., Bolte, Michael
We have obtained deep, long-slit spectroscopy along the major axis of NGC 6166, the cD galaxy in the cluster Abell 2199, in order to measure the kinematics of intracluster starlight at large radii....
The Formation Timescales of Giant Spheroids (2001)
Trager, S. C., Faber, S. M., Dressler, A.
We review current progress in the study of the stellar populations of early-type galaxies, both locally and at intermediate redshifts. In particular, we focus on the ages of these galaxies and their...
A Search for Environmental Effects on Type Ia Supernovae (2000)
Hamuy, Mario, Trager, S. C., Pinto, Philip A., Phillips, M. M., Schommer, R. A., Ivanov, Valentin, ...
We use integrated colors and B and V absolute magnitudes of Type Ia supernova (SN) host galaxies in order to search for environmental effects on the SN optical properties. With the new sample of 44...
Trager, S. C., Faber, S. M., Worthey, G., Gonzalez, J. J.
We analyze single-stellar-population (SSP) equivalent parameters for 50 local elliptical galaxies as a function of their structural parameters. These galaxies fill a two-dimensional plane in the...
The Stellar Population Histories of Local Early-Type Galaxies. I. Population Parameters (2000)
Trager, S. C., Faber, S. M., Worthey, Guy, Gonzalez, J. Jesus
We present single stellar population (SSP) equivalent ages, metallicities, and abundance ratios for local elliptical galaxies derived from Hbeta, Mgb, and absorption line strengths. We use an...
The Ages of Early-Type Galaxies: A Cautionary Tale (1999)
Early-type galaxies are not the simple Population II systems they have long been assumed to be. While upwards of 80% of the stellar mass of early-type galaxies likely formed at high redshift, small...
The Stellar Ages of Elliptical Galaxies (1999)
Faber, S.M., Trager, S.C., Gonzalez, J.J., Worthey, Guy
Integrated broad-band colors and metallic lines cannot discriminate clearly between the effects of age and Z in old stellar populations. Such data are more sensitive to Z than to age. The H β...
Integrated Stellar Populations of Bulges: First Results (1998)
Trager, S. C., Dalcanton, J. J., Weiner, B. J.
We present first results from an on-going survey of the stellar populations of the bulges and inner disks of spirals at various points along the Hubble sequence. In particular, we are investigating...
Old Stellar Populations. VI. Absorption-Line Spectra of Galaxy Nuclei and Globular Clusters (1997)
Trager, S. C., Worthey, Guy, Faber, S. M., Burstein, David, Gonzalez, J. J.
We present absorption-line strengths on the Lick/IDS line-strength system of 381 galaxies and 38 globular clusters in the 4000--6400 \AA region. All galaxies were observed at Lick Observatory between...
Galaxies at z=4 and the Formation of Population II (1997)
Trager, S. C., Faber, S. M., Dressler, A., Oemler, A.
We report the discovery of four high-redshift objects (3.3 < z < 4) observed behind the rich cluster CL0939+4713 (Abell 851). One object (DG 433) has a redshift of z=3.3453; the other three objects...