David R. Andersen
National Science Foundation
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Featured researches published by David R. Andersen.
Astrophysical Journal Supplement Series | 2006
David R. Andersen; Matthew A. Bershady; Linda S. Sparke; John S. Gallagher; Eric M. Wilcots; Wim van Driel; Delphine Monnier-Ragaigne
We present a survey of the photometric and kinematic properties of 39 nearby, nearly face-on disk galaxies. Our approach exploits echelle-resolution integral-field spectroscopy of the Hα regions, obtained with DensePak on the WIYN 3.5 m telescope Bench Spectrograph. These data are complemented by H I line profiles observed with the Nancay radio telescope for 25 of these sample galaxies. Twelve additional line widths are available for sample galaxies from the literature. In this paper, we introduce the goals of this survey, define the sample selection algorithm, and amass the integral field spectroscopic data and H I line widths. We establish spatially integrated Hα line widths for the sample. We test the veracity of these spatially integrated line profiles by convolving narrowband imaging data with velocity field information for one of the sample galaxies, PGC 38268, and also by comparing to H I line profiles. We find H I and Hα line profiles to be similar in width but different in shape, indicating that we are observing different spatial distributions of ionized and neutral gas in largely axisymmetric systems with flat outer rotation curves. We also find vertical velocity dispersions of the ionized disk gas within several disk scale lengths have a median value of 18 km s-1 and an 80% range of 12-26 km s-1. This is only a factor of ~2 larger than what is observed for neutral atomic and molecular gas. With standard assumptions for intrinsic and thermal broadening for Hα, this translates into a factor of 3 range in turbulent velocities, between 8 and 25 km s-1.
International Conference on Hunting for the Dark: The Hidden Side of Galaxy Formation | 2010
Kyle B. Westfall; Matthew A. Bershady; Marc Verheijen; Thomas P. K. Martinsson; David R. Andersen; Rob A. Swaters
We briefly review measurements of the disk stellar velocity ellipsoid (SVE) completed [1] for the Disk‐Mass Survey [2] and illustrate additional Calar Alto PMAS/PPak data that will supplement these results. This discussion is motivated by the fundamental physical insights into both the disk and overall gravitational potential provided by the three‐dimensional (3D) description of the SVE.
Archive | 2011
Nadine Neumayer; Carl Jakob Walcher; David R. Andersen; Hans-Walter Rix
Archive | 2008
David R. Andersen; Matthew A. Bershady; Linda S. Sparke; Joseph S. Gallagher; Eric M. Wilcots; Wim van Driel; Delphine Monnier-Ragaigne
Archive | 2007
David R. Andersen; Carl Jakob Walcher; Hans-Walter Rix; Luis C. Ho
Archive | 2007
Kyle B. Westfall; Matthew A. Bershady; Marc Verheijen; David R. Andersen; R. A. Swaters
Archive | 2006
R. A. Swaters; David R. Andersen; Matthew A. Bershady; Marc Verheijen; Kyle B. Westfall
Archive | 2002
David R. Andersen; Matthew A. Bershady
Archive | 2002
Stephane Courteau; Matthew A. Bershady; Hans-Walter Rix; David R. Andersen
NOAO Proposal | 2002
Rob A. Swaters; David R. Andersen; Matthew A. Bershady; Marc Verheijen