STAR CLUSTERS IN THE TIDAL TAILS OF INTERACTING GALAXIES: CLUSTER POPULATIONS ACROSS A VARIETY OF TAIL ENVIRONMENTS

Journal Article · Wed Apr 20 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/731/2/93· OSTI ID:21574717

Mullan, B; Konstantopoulos, I S; Lee, K H; Charlton, J C; Gronwall, C; Hunsberger, S; Palma, C ^[1]; Kepley, A A; Johnson, K E ^[2]; Knierman, K ^[3]; Bastian, N ^[4]; Chandar, R ^[5]; Durrell, P R ^[6]; Elmegreen, D ^[7]; English, J ^[8]; Gallagher, S C ^[9]; Hibbard, J E ^[10]; Maybhate, A ^[11]; Trancho, G ^[12]

---

1. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16803 (United States)
2. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
3. School of Earth and Space Exploration, Bateman Physical Sciences Center, Arizona State University, F-wing Room 686, Tempe, AZ 85287-1404 (United States)
4. School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
5. Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States)
6. Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States)
7. Department of Physics and Astronomy, Vassar College, Box 745, Poughkeepsie, NY 12604 (United States)
8. Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)
9. Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3K7 (Canada)
10. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)
11. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
12. Gemini Observatory, Casilla 603, Colina el Pino S/N, La Serena (Chile)

We have searched for compact stellar structures within 17 tidal tails in 13 different interacting galaxies using F606W- and F814W-band images from the Wide Field Planetary Camera 2 on the Hubble Space Telescope. The sample of tidal tails includes a diverse population of optical properties, merging galaxy mass ratios, H I content, and ages. Combining our tail sample with Knierman et al., we find evidence of star clusters formed in situ with M{sub V} < -8.5 and V - I < 2.0 in 10 of 23 tidal tails; we are able to identify cluster candidates to M{sub V} = -6.5 in the closest tails. Three tails offer clear examples of 'beads on a string' star formation morphology in V - I color maps. Two tails present both tidal dwarf galaxy candidates and cluster candidates. Statistical diagnostics indicate that clusters in tidal tails may be drawn from the same power-law luminosity functions (with logarithmic slopes {approx}-2 to -2.5) found in quiescent spiral galaxies and interiors of interacting systems. We find that the tail regions with the largest number of observable clusters are relatively young ({approx}<250 Myr old) and bright (V {approx}< 24 mag arcsec{sup -2}), probably attributed to the strong bursts of star formation in interacting systems soon after periapse. Otherwise, we find no statistical difference between cluster-rich and cluster-poor tails in terms of many observable characteristics, though this analysis suffers from complex, unresolved gas dynamics and projection effects.

• OSTI ID: 21574717
• Journal Information: Astrophysical Journal, Vol. 731, Issue 2; Other Information: DOI: 10.1088/0004-637X/731/2/93; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
GALAXIES
GALAXY CLUSTERS
INTERACTIONS
PHOTOMETRY
STAR CLUSTERS