Spitzer Observations of the Prototypical Extremely Red Objects HR 10 and LBDS 53W091: Separating Dusty Starbursts from Old Elliptical Galaxies
Abstract
We present Spitzer Space Telescope observations of the well-studied extremely red objects (EROs) HR 10 and LBDS 53W091 from 3.6 to 160 μm. These galaxies are the prototypes of the two primary classes of EROs: dusty starbursts and old, evolved galaxies, respectively. Both galaxies, as well as LBDS 53W069, another example of an old, quiescent galaxy, are well detected out to 8 μm. However, only the dusty starburst HR 10 is detected in the far-infrared. All three EROs have stellar masses of a few×1011 Msolar. Using evolutionary model fits to their multiband photometry, we predict the infrared colors of similar EROs at 1<z<2. We find that blueward of observed 10 μm, the two ERO classes are virtually indistinguishable photometrically. Deep spectroscopy and 24 μm data allow the classes to be separated.
- Publication:
-
The Astronomical Journal
- Pub Date:
- September 2006
- DOI:
- 10.1086/506347
- arXiv:
- arXiv:astro-ph/0607507
- Bibcode:
- 2006AJ....132.1405S
- Keywords:
-
- Galaxies: Evolution;
- galaxies: individual (HR 10);
- galaxies: individual (LBDS 53W069);
- galaxies: individual (LBDS 53W091);
- Infrared: Galaxies;
- Astrophysics
- E-Print:
- 23 pages, 4 figures