Star-Forming Brightest Cluster Galaxies at 0.25 < z < 1.25: A Transitioning Fuel Supply

• Published in: The Astrophysical Journal
• Main Authors: McDonald, M., Stalder, B., Bayliss, M. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, Harvard Univ., Cambridge, MA . Dept. of Physics, Allen, S. W. Stanford Univ., CA . Kavli Inst. for Particle Astrophysics and Cosmology; Stanford Univ., CA . Dept. of Physics; SLAC National Accelerator Lab., Menlo Park, CA, Applegate, D. E. Argelander-Inst. for Astronomy, Bonn, Ashby, M. L. N. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, Bautz, M. Massachusetts Inst. of Technology , Cambridge, MA . Kavli Inst. for Astrophysics and Space Research, Benson, B. A. Fermi National Accelerator Lab. , Batavia, IL, Univ. of Chicago, IL . Kavli Inst. for Cosmological Physics; Univ. of Chicago, IL . Dept. of Astronomy and Astrophysics, Bleem, L. E. Univ. of Chicago, IL . Kavli Inst. for Cosmological Physics; Argonne National Lab. , Argonne, IL, Univ. of Chicago, IL . Dept. of Physics, Brodwin, M. Univ. of Missouri, Kansas City, MO . Dept. of Physics and Astronomy, Carlstrom, J. E. Univ. of Chicago, IL . Kavli Inst. for Cosmological Physics; Univ. of Chicago, IL . Dept. of Astronomy and Astrophysics; Argonne National Lab. , Argonne, IL, Univ. of Chicago, IL . Dept. of Physics; Univ. of Chicago, IL . Enrico Fermi Inst., Chiu, I. Ludwig Maximilian Univ., Munich . Dept. of Physics, Desai, S. Ludwig Maximilian Univ., Munich . Dept. of Physics; Excellence Cluster Universe, Garching, Gonzalez, A. H. Univ. of Florida, Gainesville, FL . Dept. of Astronomy, Hlavacek-Larrondo, J. Univ. of Montreal, Quebec . Dept. of Physics, Holzapfel, W. L. Univ. of California, Berkeley, CA . Dept. of Physics, Marrone, D. P. Univ. of Arizona, Tucson, AZ . Steward Observatory, Miller, E. D. Massachusetts Inst. of Technology , Cambridge, MA . Kavli Inst. for Astrophysics and Space Research, Reichardt, C. L. Univ. of Melbourne . School of Physics, Saliwanchik, B. R. Case Western Reserve Univ., Cleveland, OH . Physics Dept. Center for Education and Research in Cosmology and Astrophysics, Saro, A. Ludwig Maximilian Univ., Munich . Dept. of Physics, Schrabback, T. Argelander-Inst. for Astronomy, Bonn, Stanford, S. A. Univ. of California, Davis, CA . Dept. of Physics, Stark, A. A. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, Vieira, J. D. Univ. of Illinois, Urbana, IL . Dept. of Astronomy. Dept. of Physics, Zenteno, A. Cerro Tololo Inter-American Observatory , La Serena
• Language: unknown
• Published: 2022
• Subjects: 79 ASTRONOMY AND ASTROPHYSICS; South Pole; Hubble; South pole
• Online Access: http://www.osti.gov/servlets/purl/1271012; https://www.osti.gov/biblio/1271012; https://doi.org/10.3847/0004-637X/817/2/86

In this paper, we present a multiwavelength study of the 90 brightest cluster galaxies (BCGs) in a sample of galaxy clusters selected via the Sunyaev Zel'dovich effect by the South Pole Telescope, utilizing data from various ground- and space-based facilities. We infer the star-formation rate (SFR) for the BCG in each cluster—based on the UV and IR continuum luminosity, as well as the [O ii]λλ3726,3729 emission line luminosity in cases where spectroscopy is available—and find seven systems with SFR > 100 M ⊙ yr -1 . We find that the BCG SFR exceeds 10 M ⊙ yr -1 in 31 of 90 (34%) cases at 0.25 < z < 1.25, compared to ~1%–5% at z ~ 0 from the literature. At z ≳ 1, this fraction increases to ${92}_{-31}^{+6}$%, implying a steady decrease in the BCG SFR over the past ~9 Gyr. At low-z, we find that the specific SFR in BCGs is declining more slowly with time than for field or cluster galaxies, which is most likely due to the replenishing fuel from the cooling ICM in relaxed, cool core clusters. At z ≳ 0.6, the correlation between the cluster central entropy and BCG star formation—which is well established at z ~ 0—is not present. Instead, we find that the most star-forming BCGs at high-z are found in the cores of dynamically unrelaxed clusters. We use data from the Hubble Space Telescope to investigate the rest-frame near-UV morphology of a subsample of the most star-forming BCGs, and find complex, highly asymmetric UV morphologies on scales as large as ~50–60 kpc. Finally, the high fraction of star-forming BCGs hosted in unrelaxed, non-cool core clusters at early times suggests that the dominant mode of fueling star formation in BCGs may have recently transitioned from galaxy–galaxy interactions to ICM cooling.