Nicole P. Vogt

The i-band tully-fisher relation for cluster galaxies: a template relation, its scatter and bias corrections

Infrared I band photometry and velocity widths for galaxies in 24 clusters, with radial velocities between 1,000 and 10,000 kms, are used to construct a template Tully--Fisher (TF) relation. The sources of scatter in the TF diagram are analyzed in detail; it is shown that the common practice of referring to a single figure of TF scatter is incorrect and can lead to erroneous bias corrections. Biases resulting from sample incompleteness, catalog inaccuracies, cluster size and other sources, as well as dependences of TF parameters on morphological type and local environment, are discussed and appropriate corrections are obtained. A template TF relation is constructed by combining the data from the 24 clusters, and kinematic cluster offsets from a putative reference frame which well approximates null velocity with respect to the cosmic microwave background, are obtained.

The I band Tully-Fisher relation for cluster galaxies: data presentation.

Observational parameters which can be used for redshift-independent distance determination using the Tully-Fisher (TF) technique are given for 782 spiral galaxies in the fields of 24 clusters or groups. I band photometry for the full sample was either obtained by us or compiled from published literature. Rotational velocities are derived either from 21 cm spectra or optical emission line long--slit spectra, and converted to a homogeneous scale. In addition to presenting the data, a discussion of the various sources of error on TF parameters is introduced, and the criteria for the assignment of membership to each cluster are given. The construction of a TF template, bias corrections and cluster motions are discussed in an accompanying paper.

M/L, Hα Rotation Curves, and H I Gas Measurements for 329 Nearby Cluster and Field Spirals. II. Evidence for Galaxy Infall

We have conducted a study of optical and H I properties of spiral galaxies (size, luminosity, Hflux distribu- tion, circular velocity, H I gas mass) to explore the role of gas stripping as a driver of morphological evolution in clusters. We find a strong correlation between the spiral a nd S0 fractions within clusters, and the spiral fraction scales tightly with cluster X-ray gas luminosity. We explore young star formation and identify spirals that are (1) asymmetric, with truncated Hemission and H I gas reservoirs on the leading edge of the disk, on a first pass through the dense intracluster medium in the core s of rich clusters; (2) strongly H I deficient and stripped, with star formation confined to the inner 5 h -1 kpc and 3 disk scale lengths; (3) reddened, extremely H I deficient and quenched, where star formation has been halted across the entire disk. We propose that these spirals are in successive stages of morphological transfor mation, between infalling field spirals and cluster S0s, and that the process which acts to remove the H I gas reservoir suppresses new star formation on a similarly fast timescale. These data suggest that gas stripping plays a significant role in morphological transformation and rapid truncation of star formation across the disk. Subject headings:galaxies: clusters — galaxies: evolution — galaxies: kinematics and dynamics

M/L, Hα Rotation Curves, and H I Measurements for 329 Nearby Cluster and Field Spirals. I. Data

A survey of 329 nearby galaxies (redshift z < 0.045) has been conducted to study the distribution of mass and light within spiral galaxies over a range of environments. The 18 observed clusters and groups span a range of richness, density, and X-ray temperature and are supplemented by a set of 30 isolated field galaxies. Optical spectroscopy taken with the 200 inch (5 m) Hale Telescope provides separately resolved Hα and [N II] major-axis rotation curves for the complete set of galaxies, which are analyzed to yield velocity widths and profile shapes, extents, and gradients. H I line profiles provide an independent velocity width measurement and a measure of H I gas mass and distribution. I-band images are used to deconvolve profiles into disk and bulge components, to determine global luminosities and ellipticities, and to check morphological classification. These data are combined to form a unified data set ideal for the study of the effects of environment upon galaxy evolution.

The rotation curves of galaxies at intermediate redshift

We have undertaken a pilot project to measure the rotation velocities of spiral galaxies in the redshift range 0.18≤z≤0.4 using high-dispersion long-slit spectroscopy obtained with the Palomar 5 m telescope. One field galaxy and three cluster objects known to have strong emission lines were observed over wavelength ranges covering the redshifted lines of [O II], Ca II K, Hβ, and [O III]. Two of the objects show extended line emission that allows the tracing of the rotation curve in one or more lines. A line width similar to that obtained with single-dish telescopes for the 21 cm H I line observed in lower redshift galaxies can be derived from the observed Hβ, [O II], and [O III] emission by measuring a characteristic width from the velocity histogram

M/L, Hα Rotation Curves, and H I Gas Measurements for 329 Nearby Cluster and Field Spirals. III. Evolution in Fundamental Galaxy Parameters

We have conducted a study of optical and H I properties of spiral galaxies (size, luminosity, Hflux distri- bution, circular velocity, H I gas mass) to investigate causes (e.g., nature versus nurture) for variation within the cluster environment. We find H I deficient cluster galaxies to be offset in Fundamental Plane space, with disk scale lengths decreased by a factor of 25%. This may be a relic of early galaxy formation, caused by the disk coalescing out of a smaller, denser halo (e.g., higher concentration index) or by truncation of the hot gas envelope due to the enhanced local density of neighbors, though we cannot completely rule out the effect of the gas stripping process. The spatial extent of Hflux and the B-band radius also decreases, but only in early type spirals, suggesting that gas removal is less efficient w ithin steeper potential wells (or that stripped late type spirals are quickly rendered unrecognizable). We find n o significant trend in stellar mass-to-light ratios or circular velocities with H I gas content, morphological type, or clustercentric radius , for star forming spiral galaxies throughout the clusters. These data support the fin dings of a companion paper that gas stripping pro- motes a rapid truncation of star formation across the disk, a nd could be interpreted as weak support for dark matter domination over baryons in the inner regions of spiral galaxies. Subject headings:galaxies: clusters — galaxies: evolution — galaxies: kinematics and dynamics

THE NEAR-INFRARED TULLY-FISHER RELATION: A PRELIMINARY STUDY OF THE COMA AND ABELL 400 CLUSTERS

We have started a large project to study the near-infrared luminosity-linewidth (Tully-Fisher) relation using H- and I-band surface photometry of spiral galaxies. A preliminary study of 20 spirals in the Coma and Abell 400 clusters (both at ~7000 km s-1) is presented. The near-infrared images have been used to derive accurate inclinations and total magnitudes, and rotational line widths are measured from high quality 21 cm Arecibo data. The scatter in the Coma Tully-Fisher plot is found to be 0.19 mag in the H-band and 0.20 mag in the I-band for a set of 13 galaxies, if we assume that they are all at the same distance. The deviation of the Coma galaxies from the best-fit Tully-Fisher relation is correlated with their redshift, indicating that some of the galaxies are not bound to the cluster. Indeed, if we treat all the galaxies in the Coma sample as undergoing free Hubble expansion, the Tully-Fisher scatter drops to 0.12 mag and 0.13 mag for the H- and I-band datasets, respectively. The Abell 400 sample is best fit by a common distance model, yielding a scatter of 0.12 mag for seven galaxies in H using a fixed Tully-Fishr slope (derived from our Coma H sample). We are in the process of studying cluster and field spirals out to ~10,000 km s-1 in order to calibrate the near-infrared Tully-Fisher relation and will apply it to more nearby galaxies to measure the peculiar velocity field (and hence the mass distribution) in the local Universe.