JHU 2375

The most distant field galaxy imaged with adaptive optics

J. Larkin, T. Glassman (UCLA), D. C. Koo, E. Steinbring, N. Cardiel, A. C. Phillips, C. N. A. Willmer (UCSC), B. Holden (UC Davis)

In a joint project involving the teams studying distant galaxies at UCLA and UCSC, we have used the Keck AO system to obtain near-infrared images of what may be the most distant field galaxy imaged with adaptive optics (AO).

The galaxy is JHU 2375, from a catalogue created by Robert Brunner (Caltech), Matt Bershady (U of Wisconsin) and A. Connolly (U. of Pittsburgh) in a subsection of the Kapteyn Selected Area 68:

Parameters for JHU 2375

R.A. 00:17:13.88 2000.0
DEC. 15:46:15.65 2000.0
z 0.5308
i 20.30
v-i 0.62
Mb -22.9 H0 =70, q0=0.1
(U-B)0 -0.55

Figure 1

JHU 2375 has broad band ground-based images in UBRI (by Brunner et al.), in J and K' (non-AO) by DEEP, and HST images using the Wide Field and Planetary Camera (WFPC2) in F606W and F814W. On the left is the WFPC2 F814W image. To the right of this is a Keck AO/NIRSPEC K' image resampled at the WFPC2 pixel scale. Next to this is the original K' image smoothed to simulate the larger diffraction pattern for NICMOS and resampled to the WFPC2 pixel scale. The image furthest to the right simulates the K' image under natural seeing conditions. N is to the top and E towards the left.

Figure 2

False colour image obtained by non-AO imaging in J and K' using NIRSPEC for the galaxy. Orientation is N to the top left corner and E to the bottom left corner. Compare with the simulated image displayed in rightmost image in the panel above.

Figure 3

False colour image combining HST V, I and the resampled Keck AO observations. Regions with intense star formation appear blue, N is to the top and E towards the left. while older stellar populations have a yellowish colour.

Figure 4

Keck LRIS spectrum in the blue (top) and red (bottom). In the middle the region around prominent emission-lines is blown-up clearly showing the rotation curve of this galaxy

Last modified: Tue Oct 24 18:12:32 2000