UKIRT and HST imaging of Abell 68
UNITED KINGDOM INFRARED TELESCOPE
Newsletter
Issue 10, Spring 2002
|
UKIRT and HST
imaging of Abell 68
|
|
|
|
|
A true colour RK view of
the central square arcminute of Abell 68 (z=0.26), exploiting the
superlative spatial resolution of Smith et al.'s (2002, MNRAS, 330, 1)
UKIRT (FWHM~0.4") and HST imaging data. Smith et al.'s survey for
gravitationally lensed EROs revealed this spectacular gravitational
lens system in which the foreground galaxy cluster (A 68) produces
three images of a single background galaxy (ERO J003707 — marked
A,B,C). More recently, Smith et al. (2002b, in prep.) have combined
near-infrared spectroscopic observations with CGS4/UKIRT and
NIRSPEC/Keck-II to measure the redshift of this ERO: z=1.60. The
intriguing aspect of this galaxy is that, whilst its extremely red
colour (R-K=5.4) is dominated by a central bulge of old stars, it also
possesses a star forming disk. This is at odds with the current view
that EROs are either elliptical galaxies or dust-reddened emission
line galaxies at z~1-2. This result has important implications for
future attempts to use EROs to constrain the formation epoch of
massive elliptical galaxies.
|
|
Image and text courtesy of Graham Smith & Ian
Smail, Univ. of Durham, UK.
|
UNITED KINGDOM INFRARED TELESCOPE
Newsletter
Issue 10, Spring 2002
|