Bradley A. Jacobs

THE EXTRAGALACTIC DISTANCE DATABASE

A database can be accessed on the Web at http://edd.ifa.hawaii.edu that was developed to promote access to information related to galaxy distances. The database has three functional components. First, tables from many literature sources have been gathered and enhanced with links through a distinct galaxy naming convention. Second, comparisons of results both at the levels of parameters and of techniques have begun and are continuing, leading to increasing homogeneity and consistency of distance measurements. Third, new material is presented arising from ongoing observational programs at the University of Hawaii 2.2 m telescope, radio telescopes at Green Bank, Arecibo, and Parkes and with the Hubble Space Telescope. This new observational material is made available in tandem with related material drawn from archives and passed through common analysis pipelines.

Cosmicflows-2: The Data

Cosmicflows-2 is a compilation of distances and peculiar velocities for over 8000 galaxies. Numerically the largest contributions come from the luminosity-line width correlation for spirals, the Tully-Fisher relation (TFR), and the related fundamental plane relation for E/S0 systems, but over 1000 distances are contributed by methods that provide more accurate individual distances: Cepheid, tip of the red giant branch (TRGB), surface brightness fluctuation, Type Ia supernova, and several miscellaneous but accurate procedures. Our collaboration is making important contributions to two of these inputs: TRGB and TFR. A large body of new distance material is presented. In addition, an effort is made to ensure that all the contributions, both our own and those from the literature, are on the same scale. Overall, the distances are found to be compatible with a Hubble constant H 0 = 74.4 ? 3.0?km?s?1?Mpc?1. The great interest going forward with this data set will be with velocity field studies. Cosmicflows-2 is characterized by a great density and high accuracy of distance measures locally, falling to sparse and coarse sampling extending to z = 0.1.

The Extragalactic Distance Database: Color-Magnitude Diagrams

The color-magnitude diagrams/tip of the red giant branch (CMDs/TRGB) section of the Extragalactic Distance Database contains a compilation of observations of nearby galaxies from the Hubble Space Telescope. Approximately 250 (and increasing) galaxies in the Local Volume have CMDs and the stellar photometry tables used to produce them available through the Web. Various stellar populations that make up a galaxy are visible in the CMDs, but our primary purpose for collecting and analyzing these galaxy images is to measure the TRGB in each. We can estimate the distance to a galaxy by using stars at the TRGB as standard candles. In this paper, we describe the process of constructing the CMDs and make the results available to the public.

IDENTIFICATION OF A COMPLETE 160 μm FLUX-LIMITED SAMPLE OF INFRARED GALAXIES IN THE ISO LOCKMAN HOLE 1 deg 2 DEEP FIELDS: SOURCE PROPERTIES AND EVIDENCE FOR STRONG EVOLUTION IN THE FIR LUMINOSITY FUNCTION FOR ULIRGs

We have identified a complete, flux-limited (S_(160) > 120 mJy) sample of 160 μm selected sources from Spitzer observations of the 1 deg^2 Infrared Space Observatory (ISO) Deep Field region in the Lockman Hole (LH). Ground-based UV, optical, and near-infrared (NIR) photometry and optical spectroscopy have been used to determine colors, redshifts, and masses for the complete sample of 40 galaxies. Spitzer-IRAC+MIPS photometry, supplemented by ISOPHOT data at 90 μm and 170 μm, has been used to calculate accurate total infrared luminosities, L_(IR)(8-1000 μm), and to determine the IR luminosity function (LF) of luminous infrared galaxies (LIRGs). The maximum observed redshift is z ~ 0.80 and the maximum total infrared luminosity is log (L_(IR)/L_⊙) = 12.74. Over the luminosity range log (L_(IR)/L_⊙)) = 10-12, the LF for LIRGs in the LH Deep Field is similar to that found previously for local sources at similar infrared luminosities. The mean host galaxy mass, log (M/M_⊙ ) = 10.7, and dominance of H_(II)-region spectral types, is also similar to what has been found for local LIRGs, suggesting that intense starbursts likely power the bulk of the infrared luminosity for sources in this range of L_(IR). However for the most luminous sources, log (L_(IR)/L_⊙ ) > 12.0, we find evidence for strong evolution in the LF ∝ (1 + z)^(6±1), assuming pure number density evolution. These ultraluminous infrared galaxies (ULIRGs) have a larger mean host mass, log (M/M_⊙) = 11.0, and exhibit disturbed morphologies consistent with strong interactions/mergers, and they are also more likely to be characterized by starburst-active galactic nucleus (AGN) composite or AGN spectral types.