HOW ROBUST ARE THE SIZE MEASUREMENTS OF HIGH-REDSHIFT COMPACT GALAXIES?

High - redshift elliptical galaxies : are they ( all ) really compact ?

We investigate the properties of 12 ultramassive passively evolving early-type galaxies (ETGs) at zphot > 1.4 in the COSMOS 2 deg2 field. These 12 ETGs were selected as pBzKs, have accurate 1.4 zphot 1.7, high Sérsic index profiles typical of ellipticals, no detection at 24μm, resulting in a complete ETG sample at M∗ > 2.5 × 1011 M (Chabrier initial mass function). Contrary to the previous clai...

Compact High-Redshift Galaxies Are the Cores of the Most Massive Present-Day Spheroids

Observations suggest that the effective radii of high-redshift massive spheroids are as much as a factor ∼ 6 smaller than low-redshift galaxies of comparable mass. Given the apparent absence of low-redshift counterparts, this has often been interpreted as indicating that the high density, compact red galaxies must be “puffed up” by some mechanism. We compare the ensemble of high-redshift observ...

How Massive Are Massive Compact Galaxies?

Using a sample of nine massive compact galaxies at z ∼ 2.3 with rest-frame optical spectroscopy and comprehensive U → 8μm photometry we investigate how assumptions in SED modeling change the stellar mass estimates of these galaxies, and how this affects our interpretation of their size evolution. The SEDs are fit to τ -models with a range of metallicities, dust laws, as well as different stella...

Galaxies at High Redshift

Galaxies at High Redshift

Within just the last few years, we have advanced from knowing only a few galaxies at z > 2 to having redshifts for nearly 1000 z ∼ 2–5 objects. The majority of this sample has been detected through the photometric “dropout” technique used so successfully by Steidel and his collaborators. In addition, a handful of objects have already been detected at z > 5, and we may already have a few objects...