Galaxies

GALAXIES

UMass astronomers are pursuing research on nearby galaxies using a wide range of tools and techniques spanning radio waves to X-rays. The more than one million galaxies detected by 2MASS, combined with redshift surveys, are producing the first view of the texture of the distribution of galaxies in the local universe unhindered by intervening dust in our own Milky Way. These measurements will constrain conditions which prevailed in the early universe and, given that they will detect structures to distances of several hundred megaparsecs, will complement millimeter-wave studies of the inhomogeneity in the cosmic microwave background. The infrared selected galaxies will produce not just a slice of the local universe, but a picture of the distribution in a complete volume that extends to more that twice the distance of early redshift surveys (z=0.1).

Other questions UMass astronomers are addressing use facilities at FCRAO, Kitt Peak National Observatory, the VLA, the NRO in Japan, and the JCMT in Hawaii. These questions include the following: Do the disks of spiral galaxies of different Hubble type display different star formation rates and/or efficiencies? Do galaxies with low star formation rates have any significant gas reservoir in the interstellar medium? How long can the high star formation rates observed in some galaxies be sustained, given the observed supply of interstellar gas? Are active galactic nuclei the result of unusually high star formation rates, efficiencies, or both? The answers to these and related questions will constrain models of the formation and evolution of galaxies and of the origin of structures within galaxies. In addition, the high angular resolution of the LMT will make that instrument ideal for investigating the nuclei of active galaxies and the origin of spiral structure.