Strong size evolution of the most massive galaxies since z∼ 2 |
| |
| Authors: | Ignacio Trujillo † C J Conselice Kevin Bundy M C Cooper P Eisenhardt Richard S Ellis |
| |
| Institution: | School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD;Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Rm 101, Toronto ONM5S 3H4, Canada;Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720, USA;Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA;Caltech MC 105-24, 1201 East California Boulevard, Pasadena, CA 91125, USA |
| |
| Abstract: | Using the combined capabilities of the large near-infrared Palomar/DEEP-2 survey, and the superb resolution of the Advanced Camera for Surveys HST camera, we explore the size evolution of 831 very massive galaxies ( M ?≥ 1011 h ?270 M⊙) since z ～ 2 . We split our sample according to their light concentration using the Sérsic index n . At a given stellar mass, both low ( n < 2.5) and high ( n > 2.5) concentrated objects were much smaller in the past than their local massive counterparts. This evolution is particularly strong for the highly concentrated (spheroid like) objects. At z ～ 1.5 , massive spheroid-like objects were a factor of 4 (±0.4) smaller (i.e. almost two orders of magnitudes denser) than those we see today. These small sized, high-mass galaxies do not exist in the nearby Universe, suggesting that this population merged with other galaxies over several billion years to form the largest galaxies we see today. |
| |
| Keywords: | galaxies: elliptical and lenticular cD galaxies: evolution galaxies: formation galaxies: fundamental parameters galaxies: high-redshift galaxies: structure |
|
|
