Clocking the formation of today's largest galaxies: wide field integral spectroscopy of brightest cluster galaxies and their surroundings

Author(s):Show less -

Edwards, V, Louise O. ; Salinas, Matthew ^[1] ; Stanley, Steffanie ^[1] ; West, Priscilla E. Holguin ^[1] ; Trierweiler, Isabella ^{[2, 3]} ; Alpert, Hannah ^{[2, 4]} ; Coelho, Paula ^[5] ; Koppaka, Saisneha ^[2] ; Tremblay, Grant R. ^[6] ; Martel, Hugo ^{[7, 8]} ; Li, Yuan ^[9]

Affiliation

^[1] Edwards, Louise O., V, Cal Poly State Univ, Dept Phys, San Luis Obispo, CA 93407 - USA

^[2] Yale Univ, Dept Phys & Astron, New Haven, CT 06520 - USA

^[3] Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 - USA

^[4] Stanford Univ, Aeronaut & Astronaut Dept, Stanford, CA 94305 - USA

^[5] Univ Sao Paulo, Dept Astron, IAG, BR-05508909 Sao Paulo - Brazil

^[6] Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 - USA

^[7] Univ Laval, Dept Phys Genie Phys & Opt, Quebec City, PQ G1V 0A6 - Canada

^[8] Ctr Rech Astrophys Quebec, CP 6128, Succ Ctr Ville, Monteal, PQ H3C 3J7Q - Canada

^[9] Flatiron Inst, CCA, New York, NY 10010 - USA

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 491, n. 2, p. 2617-2638, JAN 2020.
• Web of Science Citations: 0

Abstract

The formation and evolution of local brightest cluster galaxies (BCGs) is investigated by determining the stellar populations and dynamics from the galaxy core, through the outskirts and into the intracluster light (ICL). Integral spectroscopy of 23 BCGs observed out to 4 re is collected and high signal-to-noise regions are identified. Stellar population synthesis codes are used to determine the age, metallicity, velocity, and velocity dispersion of stars within each region. The ICL spectra are best modelled with populations that are younger and less metalrich than those of the BCG cores. The average BCG core age of the sample is 13.3 +/- 2.8Gyr and the average metallicity is {[}Fe/H] = 0.30 +/- 0.09, whereas for the ICL the average age is 9.2 +/- 3.5Gyr and the average metallicity is {[}Fe/H] = 0.18 +/- 0.16. The velocity dispersion profile is seen to be rising or flat in most of the sample (17/23), and those with rising values reach the value of the host cluster's velocity dispersion in several cases. The most extended BCGs are closest to the peak of the cluster's X-ray luminosity. The results are consistent with the idea that the BCG cores and inner regions formed quickly and long ago, with the outer regions and ICL forming more recently, and continuing to assemble through minor merging. Any recent star formation in the BCGs is a minor component, and is associated with the cluster cool core status. (AU)

• FAPESP's process: 18/05392-8 - A new library of fully theoretical stellar population models
• Grantee: Paula Rodrigues Teixeira Coelho
• Support Opportunities: Regular Research Grants