Research Description

Extragalactic HI Surveys

Most galaxy surveys select galaxies by their starlight. It is only with blind 21cm surveys that we can determine the nature of the gas-rich galaxy population in the local universe in an unbiased way. Determining the nature of this population and calculating the HI mass function is an important z=0 constraint for models of galaxy evolution. In addition, these surveys can be used to study the make-up of the local damped Lyman-alpha absorber population for comparison with high redshift observations. As the size of these surveys grows, we will be able to study how the HI mass function and properties of gas-rich galaxies change as a function of environment, allowing us to look at how evolution has affected gas-rich galaxies.

My thesis work was on the Arecibo Dual-Beam Survey (ADBS), which was the largest HI survey at the time, identifying 265 gas-rich galaxies in the local universe. HIPASS has now been completed with the Parkes telescope surpassing the ADBS but with less depth and lower spatial resolution. The next advance in HI surveys will come from the extragalactic consortium projects that have recently begun with the new multibeam receiver on the Arecibo telescope. As a member of several of these projects I am actively engaged in the push to create much larger and deeper HI surveys than what has come before.
Arecibo Telescope
The ALFA Receiver

Associated References:

  • The Arecibo Legacy Fast ALFA Survey: I. Science Goals, Survey Design, and Strategy, Giovanelli, R., Haynes, M.P., Kent, B.R., Perillat, P., Saintonge, A., Brosch, N., Catinella, B., Hoffman, G.L., Stierwalt, S., Spekkens, K., Lerner, M., Masters, K.L., Momjian, E., Rosenberg, J., Springob, C.M. plus 25 others, 2005, AJ, in press.

  • The Arecibo Legacy Fast ALFA Survey: II. Results of Precursor Observations, Giovanelli, R., Haynes, M. P., Kent, B. R., Perillat, P., Catinella, B., Hoffman, G. L., Momjian, E., Rosenberg, J. L., Saintonge, A., Spekkens, K., Stierwalt, S., Brosch, N., Masters, K. L., Springob, C. M., Karachentsev, I. D., Karachentseva, V. E., Koopmann, R. A., Muller, E., van Driel, W., van Zee, L. 2005, AJ, submitted.

  • Gas and Stars in an HI-Selected Sample, Rosenberg, J. L., Schneider, S. E., Posson-Brown, J. 2005, AJ, 129, 1311.

  • ALFA Shallow Survey/ZOA White Paper, 2003, Rosenberg, J. L., Henning, P., Putman, M., Davies, J., Brosch, N., Giovanelli, R., Darling, J., Tully, B., Kilborn, V., Bruens, C., Hoffman, L., Pantoja, C.

  • The Contribution of HI-rich Galaxies to the Damped Lyman-alpha Absorber Population at z=0, Rosenberg, J. L. & Schneider, S. E. 2003, 585, 256.

  • The Arecibo Dual-Beam Survey: The HI Mass Function of Galaxies, Rosenberg, J. L. & Schneider, S. E. 2002, ApJ, 568, 1.

  • The Arecibo Dual-Beam Survey: Arecibo and VLA Observations, Rosenberg, J. L. & Schneider, S. E. 2000, ApJS, 130,177.

  • Discovery of New Galaxies Veiled by the Milky Way, Jarrett, T., Chester, T., Cutri, R., Hurt, R., Schneider, S. E., Rosenberg, J. L., Huchra, J., & Mader, J. 2000, AJ, 120, 298.


    Connection Between Gas-Rich Galaxies and the Intergalactic Medium

    Where do galaxy halos end, where does the IGM begin? How does the size of the halo and the spread of metals away from galaxies depend on the properties of the associated galaxy? The Cosmic Origins Spectrograph (COS), the next generation UV spectrograph for the Hubble Space Telescope, should be a tremendous advance in answering these questions with its ability to obtain high SNR (R=30,000) spectra of 17th mag QSOs in only a few orbits. I have worked on finding galaxy/QSO pair candidates for observation with this instrument to test these very questions, but the servicing mission to install the instrument on HST has been cancelled. To try to observe the best candidate out of our sample, a galaxy surrounded by 3 QSOs,I suscessfully applied for STIS time in Cycle 13. To make matters worse, STIS failed before the observations could be taken. Until we get a new UV spectrograph, progress on this work will be impossible.

    To understand the relationship between galaxies and absorbers it is also important to look for galaxies in the immediate vicinity of the absorber. Mary Putman and I have led a 21 cm search for gas-rich, low-luminosity systems in the vicinity of absorbers. So far the work seems to indicate that the low column density absorbers (not the damped absorbers or the Lyman-limit systems which are identified with galaxy disks and galaxy halos respectively) are part of the same large scale structures as the galaxies, but not directly associated with an individual galaxy.
    Hubble Space Telescope
    RA Coone Diagram of PG1116

    Associated References:

  • The Relationship between Baryons and Dark Matter in Extended Galaxy Halos, Putman, M. E., Rosenberg, J. L., Stocke, J. T., McEntaffer, R. 2005, submitted.

  • Probing the Size of Low-Redshift Ly-alpha Absorbers, Rosenberg, J. L., Ganguly, R., Giroux, M. L., Stocke, J. T. 2003, ApJ, 609, 94.


    Star Formation in Local Dwarf Galaxies

    Star-forming dwarf galaxies in the local universe tend to be low metallicity, low mass, and gas-rich. These systems have properties that are the most similar to objects we would expect to exist at high redshift in a hierarchical universe. Therefore, understanding the physical processes like star formation in these objects will provide an important clue to those undergone by high redshift systems. Already I have used the Spitzer data to shown that these galaxies have diverse mid-infrared properties with their mid-infrared dust emission more strongly correlated with the optically determined star-formation rate then it is with metallicity or optical reddening. In addition, the comparison of the properties of these objects with those of mid-infrared faint Lyman-break galaxies may indicate that a subsample of the Lyman-break galaxies are low mass systems with properties similar to these objects. As the Spitzer data is pouring in there are clearly many intriguing observations to be pursued and much more that will be learned about the nature of nearby star-forming dwarf galaxies.

    IRAC color composite of KISS galaxy

    Associated References:

  • The Diverse Infrared Properties of Star-Forming Dwarf Galaxies, Rosenberg, J. L., Ashby, M. L. N., Salzer, J. J., Huang, J. -S. 2006, ApJ, in press.

  • Infrared Luminous Lyman Break Galaxies: A Population that Bridges LBGs and SCUBA Galaxies, Huang, J. -S., Rigopoulou, D., Willner, S. P., Papovich, C., Shu, C., Ashby, M. L. N., Barmby, P., Bundy, K., Conselice, C., Egami, E., Perez-Gonzalez, P. G., Rosenberg, J. L., Smith, H. A., Wilson, G., Fazio, G. G. 2005, ApJ, in press.

  • An HI Survey of Actively Star-Forming Dwarf Galaxies, Salzer, J. J., Rosenberg, J. L., Weisstein, E. W., Mazzarella, J. M., Bothun, G. D. 2002, AJ, 124, 191.

  • Emission-Line Galaxy Surveys as Probes of the Spatial Distribution of Dwarf Galaxies I: The University of Michigan Survey, Lee, J. C., Salzer, J. J., Law, D. A., & Rosenberg, J. L. 2000, ApJ, 536, 606.

  • Emission-Line Galaxies in the Slice of the Universe. II. The Deep Case Survey Sample, Rosenberg, J. L., Salzer, J. J., & Moody, J. W., 1994, AJ, 108, 1557

  • Imaging and Spectroscopic Observations of the Case Survey Blue/Emission-Line Galaxies, Salzer, J. J., Moody, J.W., Rosenberg, J. L., Gregory, S. A., & Newberry, M. V., 1995, AJ, 109, 2376