STRUCTURES OF LOCAL GALAXIES COMPARED TO HIGH-REDSHIFT STAR-FORMING GALAXIES
- Department of Physics, The Catholic University of America, Washington, DC 20064 (United States)
- Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States)
- Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- National Optical Astronomical Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States)
The rest-frame far-ultraviolet morphologies of eight nearby interacting and starburst galaxies (Arp 269, M 82, Mrk 8, NGC 520, NGC 1068, NGC 3079, NGC 3310, and NGC 7673) are compared with 54 galaxies at z {approx} 1.5 and 46 galaxies at z {approx} 4 observed in the Great Observatories Origins Deep Survey (GOODS) taken with the Advanced Camera for Surveys onboard the Hubble Space Telescope. The nearby sample is artificially redshifted to z {approx} 1.5 and 4 by applying luminosity and size scaling. We compare the simulated galaxy morphologies to real z {approx} 1.5 and 4 UV-bright galaxy morphologies. We calculate the Gini coefficient (G), the second-order moment of the brightest 20% of the galaxy's flux (M {sub 20}), and the Sersic index (n). We explore the use of nonparametric methods with two-dimensional profile fitting and find the combination of M {sub 20} with n an efficient method to classify galaxies as having merger, exponential disk, or bulge-like morphologies. When classified according to G and M {sub 20} 20/30% of real/simulated galaxies at z {approx} 1.5 and 37/12% at z {approx} 4 have bulge-like morphologies. The rest have merger-like or intermediate distributions. Alternatively, when classified according to the Sersic index, 70% of the z {approx} 1.5 and z {approx} 4 real galaxies are exponential disks or bulge-like with n>0.8, and {approx} 30% of the real galaxies are classified as mergers. The artificially redshifted galaxies have n values with {approx} 35% bulge or exponential at z {approx} 1.5 and 4. Therefore, {approx} 20%-30% of Lyman-break galaxies have structures similar to local starburst mergers, and may be driven by similar processes. We assume merger-like or clumpy star-forming galaxies in the GOODS field have morphological structure with values n < 0.8 and M {sub 20}> - 1.7. We conclude that Mrk 8, NGC 3079, and NGC 7673 have structures similar to those of merger-like and clumpy star-forming galaxies observed at z {approx} 1.5 and 4.
- OSTI ID:
- 21255678
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 138, Issue 2; Other Information: DOI: 10.1088/0004-6256/138/2/362; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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