PI: Kimberly A Herrmann, Pennsylvania State U., firstname.lastname@example.org
Address: 1 Campus Drive, Mont Alto, Pennsylvania 17237 United States
CoI: Deidre A Hunter, Lowell Observatory
CoI: Robin B Ciardullo, Pennsylvania State U.
CoI: George H Jacoby, GMT
CoI: Megan Johnson, CSIRO
CoI: Hongxin Zhang, Kavli Institute for Astronomy and Astrophysics
Title: Planetary Nebula Dynamics in Dwarf Irregular Galaxies
Abstract: Dwarf galaxies are the most common type of galaxy in the universe and (apparently) fairly simple systems, yet there are still many aspects about their structure that are unknown. Even seemingly simple details such as the thickness of their disks are controversial. Since an uncertainty in the disk thickness propagates into estimates of their mass, it is crucial that we pin down these parameters. The ratio between rotational velocity and velocity dispersion (via absorption line spectroscopy) provides information about the thickness. Unfortunately, this method cannot extend to the outer regions of dwarfs where the star light becomes much too faint. We therefore propose to use planetary nebulae (PNe) and \ion regions as kinematic probes of the old and young stellar populations throughout the disks of two dwarf irregular galaxies. This proposal is to perform follow-up spectroscopic observations of the LITTLE THINGS galaxies DDO~50 and NGC~4214 with WIYN+Hydra on $\sim150$ candidate PNe and $\sim200$ \ion regions identified from DCT (Discovery Channel Telescope) and HST narrow-band images. Velocities from spectra will be used to determine the shapes and disk surface mass of tiny dwarf galaxies and their relationship to star formation and surface brightness profile breaks. Additionally, the PNe will be useful to probe metallicity and chemical abundances.
Program Type: Standard/Extragalactic
Run 1 (2015A): WIYN/HYDR -- 4n on Feb 19 - Feb 22 2015
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360