Abstract
We present an in-depth analysis of the Butcher-Oemler cluster A2111, including new optical spectroscopy plus a deep Very Large Array (VLA) radio continuum observation. These are combined with optical imaging from the Sloan Digital Sky Survey (SDSS) to assess the activity and properties of member galaxies. Prior X-ray studies have suggested A2111 to be a head-on cluster merger, a dynamical state that might be connected to the high level of activity inferred from its blue fraction. We are able to directly assess this claim, using our spectroscopic data to identify 95 cluster members among 196 total galaxy spectra. These galaxy velocities do not themselves provide significant evidence for the merger interpretation; however, they are consistent with it provided that the system is viewed near the time of core passage and at a viewing angle
30° from the merger axis. The SDSS data allow us to confirm the high blue fraction for A2111, fb = 0.15 ± 0.03 based on photometry alone and fb = 0.23 ± 0.03 using spectroscopic data to remove background galaxies. We are able to detect 175 optical sources from the SDSS in our VLA radio data, of which 35 have redshift information. We use the SDSS photometry to determine photometric redshifts for the remaining 140 radio-optical sources. In total we identify up to 26 cluster radio galaxies, 14 of which have spectroscopic redshifts. The optical spectroscopy and radio data reveal a substantial population of dusty starbursts within the cluster. The high blue fraction and prevalence of star formation are consistent with the hypothesis that dynamically active clusters are associated with more active member galaxies than relaxed clusters.
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References
- Abazajian, K., et al. 2004, AJ, 128, 502
- Abazajian, K., et al. 2005, AJ, 129, 1755
- Adelman-McCarthy, J. K., et al. 2005, ApJS, 162, 38
- Blanton, E. L., Gregg, M. D., Helfand, D. J., Becker, R. H., & Leighly, K. M. 2001, AJ, 121, 2915
- Blanton, M. R., et al. 2003, AJ, 125, 2348
- Dressler, A., Smail, I., Poggianti, B. M., Butcher, H., Couch, W. J., Ellis, R. S., & Oemler, A., Jr. 1999, ApJS, 122, 51
- Dwarakanath, K. S., & Owen, F. N. 1999, AJ, 118, 625
- Eisenstein, D. J., et al. 2001, AJ, 122, 2267
- Fasano, G., Poggianti, B. M., Couch, W. J., Bettoni, D., Kjærgaard, P., & Moles, M. 2000, ApJ, 542, 673
- Hill, J. M., & Oegerle, W. R. 1998, AJ, 116, 1529
- Homeier, N. L., et al. 2005, ApJ, 621, 651
- López-Cruz, O., Barkhouse, W. A., & Yee, H. K. C. 2004, ApJ, 614, 679
- Metevier, A. J., Romer, A. K., & Ulmer, M. P. 2000, AJ, 119, 1090
- Miller, N. A. 2005, AJ, 130, 2541
- Miller, N. A., & Owen, F. N. 2002, AJ, 124, 2453
- Miller, N. A., & Owen, F. N. 2003, AJ, 125, 2427
- Miller, N. A., Owen, F. N., Hill, J. M., Keel, W. C., Ledlow, M. J., & Oegerle, W. R. 2004, ApJ, 613, 841
- Morrison, G. E., Owen, F. N., Ledlow, M. J., Keel, W. C., Hill, J. M., Voges, W., & Herter, T. 2003, ApJS, 146, 267
- Owen, F. N., Ledlow, M. J., Keel, W. C., & Morrison, G. E. 1999, AJ, 118, 633
- Owen, F. N., Ledlow, M. J., Keel, W. C., Wang, Q. D., & Morrison, G. E. 2005, AJ, 129, 31
- Poggianti, B. M., Smail, I., Dressler, A., Couch, W. J., Barger, A. J., Butcher, H., Ellis, R. S., & Oemler, A., Jr. 1999, ApJ, 518, 576
- Schlegel, D. J., Finkbeiner, D. P., & Davis, M. 1998, ApJ, 500, 525
- Shioya, Y., Bekki, K., & Couch, W. J. 2001, ApJ, 558, 42
- Smail, I., Morrison, G., Gray, M. E., Owen, F. N., Ivison, R. J., Kneib, J.-P., & Ellis, R. S. 1999, ApJ, 525, 609
- Spergel, D. N., et al. 2003, ApJS, 148, 175
- Strauss, M. A., et al. 2002, AJ, 124, 1810
- Venemans, B. P., et al. 2002, ApJ, 569, L11
- York, D. G., et al. 2000, AJ, 120, 1579
- Yun, M. S., Reddy, N. A., & Condon, J. J. 2001, ApJ, 554, 803
Citations
-
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M. S. Owers et al. 2013 The Astrophysical Journal 772 104 -
The IMACS Cluster Building Survey. III. The Star Formation Histories of Field Galaxies
Augustus Oemler, Jr. et al. 2013 The Astrophysical Journal 770 63 -
Bayesian analysis of weak gravitational lensing and Sunyaev-Zel’dovich data for six galaxy clusters★ : Analysis of lensing & SZ data for six clusters
Natasha Hurley-Walker et al 2011 Monthly Notices of the Royal Astronomical Society no -
The Dissection of Abell 2744: A Rich Cluster Growing Through Major and Minor Mergers
Matt S. Owers et al. 2011 The Astrophysical Journal 728 27 -
LoCuSS: Probing galaxy transformation physics with
Herschel
G. P. Smith et al 2010 Astronomy and Astrophysics 518 L18 -
Catalog of radio galaxies with z > 0.3. I: Construction of the sample
M. L. Khabibullina and O. V. Verkhodanov 2009 Astrophysical Bulletin 64 123 -
LoCuSS: luminous infrared galaxies in the merging cluster Abell 1758 at z= 0.28
C. P. Haines et al 2009 Monthly Notices of the Royal Astronomical Society -
LOCUSS: The Mid-Infrared Butcher-Oemler Effect
C. P. Haines et al. 2009 The Astrophysical Journal 704 126 -
Radio observations of the Horologium-Reticulum supercluster - I. A3158: excess star-forming galaxies in a merging cluster?
M. C. Fleenor et al 2008 Monthly Notices of the Royal Astronomical Society 390 289 -
The bright galaxy population of five medium redshift clusters
B. Ascaso et al 2008 Astronomy & Astrophysics 487 453 -
A 2163: Merger events in the hottest Abell galaxy cluster
S. Maurogordato et al 2008 Astronomy and Astrophysics 481 593