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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
earth and planetary sciences
Discovery of a gas-rich companion to the extremely metal-poor galaxy DDO 68
Astrophysical Journal Letters, Volume 787, No. 1, Article L1, Year 2014
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Description
We present H I spectral-line imaging of the extremely metal-poor galaxy DDO 68. This system has a nebular oxygen abundance of only 3% Z , making it one of the most metal-deficient galaxies known in the local volume. Surprisingly, DDO 68 is a relatively massive and luminous galaxy for its metal content, making it a significant outlier in the mass-metallicity and luminosity-metallicity relationships. The origin of such a low oxygen abundance in DDO 68 presents a challenge for models of the chemical evolution of galaxies. One possible solution to this problem is the infall of pristine neutral gas, potentially initiated during a gravitational interaction. Using archival H I spectral-line imaging obtained with the Karl G. Jansky Very Large Array, we have discovered a previously unknown companion of DDO 68. This low-mass ( = 2.8 × 10 7 M ), recently star-forming (SFRFUV = 1.4 × 10-3 M yr-1, SFRHα < 7 × 10-5 M yr-1) companion has the same systemic velocity as DDO 68 (V sys = 506 km s -1; D = 12.74 ± 0.27 Mpc) and is located at a projected distance of 42 kpc. New H I maps obtained with the 100 m Robert C. Byrd Green Bank Telescope provide evidence that DDO 68 and this companion are gravitationally interacting at the present time. Low surface brightness H I gas forms a bridge between these objects. © 2014. The American Astronomical Society. All rights reserved..
Authors & Co-Authors
Cannon, John M.
United States, Minneapolis
Macalester College
Johnson, Megan
Australia, Sydney
Australia Telescope National Facility
McQuinn, Kristen B.W.
United States, Minneapolis
University of Minnesota Twin Cities
Alfvin, Erik D.
United States, Minneapolis
Macalester College
Bailin, Jeremy
United States, Tuscaloosa
The University of Alabama
Ford, H. Alyson
United States, Charlottesville
National Radio Astronomy Observatory
Girardi, L.
Italy, Padua
Osservatorio Astronomico Di Padova
Hirschauer, Alec S.
United States, Bloomington
Indiana University Bloomington
Janowiecki, Steven
United States, Bloomington
Indiana University Bloomington
Salzer, John J.
United States, Bloomington
Indiana University Bloomington
Van Sistine, Angela
United States, Bloomington
Indiana University Bloomington
Dolphin, Andrew E.
United States, Waltham
Raytheon
Elson, Edward C.
South Africa, Cape Town
University of Cape Town
Koribalski, Baerbel S.
Australia, Sydney
Australia Telescope National Facility
Marigo, P.
Italy, Padua
Università Degli Studi Di Padova
Rosenberg, Jessica L.
United States, Fairfax
George Mason University
Rosenfield, Philip
Italy, Padua
Università Degli Studi Di Padova
Skillman, Evan D.
United States, Minneapolis
University of Minnesota Twin Cities
Venkatesan, Aparna
United States, San Francisco
University of San Francisco
Warren, Steven R.
United States, College Park
University of Maryland, College Park
Statistics
Citations: 20
Authors: 20
Affiliations: 13
Identifiers
Doi:
10.1088/2041-8205/787/1/L1
ISSN:
20418205
e-ISSN:
20418213