Hirohisa Tanabe

Subaru Deep Survey I. Near-Infrared Observations

Deep near-infraredimages of a blank 2 � ×2 � section of skynear the galactic north pole taken by Subaru Telescope are presented. The total integration times of the J and Kbands were 12.1 hr and 9.7 hr, resulting in 5 σ limiting magnitudes of 25.1 and 23.5 mag, respectively. The numbers of sources within these limiting magnitudes found with an automated detection procedure are 385 in the J band and 350 in K � . Based on photometric measurements of these sources, we present number count vs. magnitude relations, color vs. magnitude diagrams, size vs. color relationships, etc. The slope of the galaxy number count plotted against the AB magnitude scale is about 0.23 in the 22 to 26 AB magnitude range of both bands. The spatial number density of galaxies as well as the slopes in the faint-end region given by the Subaru Deep Field (SDF) survey are consistent with those given by HST-NICMOS surveys, as expressed on the AB magnitude diagram. Several sources having very large J − Kcolor have been found, including a few Kobjects without detection at J. In addition, a number of faint galactic stars were also

Near-Infrared Emission-Line Galaxies in the Hubble Deep Field North

We present the 2.12 yum narrow-band image of the Hubble Deep Field North taken with the nearinfrared camera (CISCO) on the Subaru telescope. Among five targets whose Ha or [O III] emission lines are redshifted into our narrow-band range expected from their spectroscopic redshift, four of them have strong emission lines, especially for the two [O III] emission-line objects. The remaining one target shows no Ha emission in spite of its bright rest-UV luminosity, indicating that this object is already under the post-starburst phase. The volume-averaged SFR derived from the detected two Ha emission is roughly consistent with that evaluated from the rest-UV continuum.

CISCO: cooled infrared spectrograph and camera for OHS

CISCO is an IR camera and spectrograph based on a single 1024 X 1024 HgCdTe array detector, which has been developed as a back-end spectrograph of OHS. It is also designed to be mounted on the Cassegrain or Nasmyth focus directly as an independent instrument. In addition to the normal imaging and spectroscopy modes, CISCO has a slitless prism spectroscopy mode at resolving power of approximately 30. This mode is primarily aimed at detecting the H(alpha) emission line of forming galaxy at z equals 2.05-2.65. The development of CISCO is in near completion, showing results of test observations carried out using a 1.5m telescope.

High-Resolution Near-Infrared Imaging of the Powerful Radio Galaxy 3C 324 at z = 1.21 with the Subaru Telescope

We have obtained high-resolution K ′ -band images of the powerful z = 1.206 radio galaxy 3C 324 with the Subaru telescope under seeing conditions of 0 ′′ .3–0 ′′ .4. We clearly resolved the galaxy and directly compared it to the optical images obtained with the Hubble Space Telescope. The host galaxy of 3C 324 is revealed to be a moderately luminous elliptical galaxy with a smooth light profile. The effective radius of the galaxy, as determined by profile fitting, is 1.3± 0 ′′ .1 (1.2 kpc), which is significantly smaller than the value of 2 ′′ .2 published in Best et al. (1998, MNRAS, 292, 758). The peak of the K ′ -band light coincides with the position of the radio core, which implies that the powerful AGN lies at the nucleus of the host galaxy. The peak also coincides with the gap in the optical knotty structures which may be a dust lane hiding the UV-optical emission of the AGN from our line of sight; it is very likely that we are seeing the obscuring structure almost edge-on. We clearly detected the ‘aligned component’ in the K ′ -band image by subtracting a model elliptical galaxy from the observed image. The red RF702W K color of the outer region of the galaxy avoiding the aligned component indicates that the near infrared light of the host galaxy is dominated by an old stellar population.