ONLY THE LONELY: H I IMAGING OF VOID GALAXIES
- Department of Astronomy, Columbia University, Mail Code 5246, 550 West 120th Street, New York, NY 10027 (United States)
- Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands)
- Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States)
- Institute of Astronomy, Swiss Federal Institute of Technology (ETH Hoenggerberg), CH-8093, Zuerich (Switzerland)
- Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States)
Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an environment undisturbed by the complex processes modifying galaxies in clusters and groups, as well as provide an observational test for theories of cosmological structure formation. We have completed a pilot survey for the H I imaging aspects of a new Void Galaxy Survey (VGS), imaging 15 void galaxies in H I in local (d < 100 Mpc) voids. H I masses range from 3.5 x 10{sup 8} to 3.8 x 10{sup 9} M{sub sun}, with one nondetection with an upper limit of 2.1 x 10{sup 8} M{sub sun}. Our galaxies were selected using a structural and geometric technique to produce a sample that is purely environmentally selected and uniformly represents the void galaxy population. In addition, we use a powerful new backend of the Westerbork Synthesis Radio Telescope that allows us to probe a large volume around each targeted galaxy, simultaneously providing an environmentally constrained sample of fore- and background control samples of galaxies while still resolving individual galaxy kinematics and detecting faint companions in H I. This small sample makes up a surprisingly interesting collection of perturbed and interacting galaxies, all with small stellar disks. Four galaxies have significantly perturbed H I disks, five have previously unidentified companions at distances ranging from 50 to 200 kpc, two are in interacting systems, and one was found to have a polar H I disk. Our initial findings suggest void galaxies are a gas-rich, dynamic population which present evidence of ongoing gas accretion, major and minor interactions, and filamentary alignment despite the surrounding underdense environment.
- OSTI ID:
- 21443123
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 1; Other Information: DOI: 10.1088/0004-6256/141/1/4; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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