Yoshihiro Chikada

Current performance and on-going improvements of the 8.2 m Subaru Telescope

An overview of the current status of the 8.2m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of Japan is presented. The basic design concept and the verified performance of the telescope system are described. Also given are the status of the instrument package offered to the astronomical community, the status of operation, and some of the future plans. The status of the telescope reported in a number of SPIE papers as of the summer of 2002 are incorporated with some updates included as of 2004 February. However, readers are encouraged to check the most updated status of the telescope through the home page, http://subarutelescope.org/index.html, and/or the direct contact with the observatory staff.

Rotational spectrum of the CCS radical studied by laboratory microwave spectroscopy and radio-astronomical observations

The rotational spectral lines of the CCS radical and its isotopic species, CC(S-34), (C-13)CS, and C(C-13)S, have been observed in the laboratory, and the J(N) = 4(3)-3(2), J(N) = 2(1)-1(0), and J(N) = 3(4)-2(3) transitions for CCS and that of J(N) = 4(3)-3(2) for CC(S-34) have been observed toward a cold dark cloud, L1498. The molecular constants of CCS, CC(S-34), (C-13)CS, and C(C-13)S have been determined from the observed transition frequencies, and the rest frequencies of CCS and CC(S-34) below 300 GHz are listed with their line strengths. The frequencies of the low-N transitions of (C-13)CS and C(C-13)S are calculated for future astronomical observations. 19 refs.

Aperture synthesis observations of the molecular environment of the Sgr A complex. I. The M-0. 13-0. 08 molecular cloud

NH{sub 3} and H{sub 2}O maser observations of the 20 km/s molecular cloud M-0.13-0.08 in the Sgr A complex region are reported. NH{sub 3} (1,1) and (2,2) lines were observed simultaneously, and the molecular gas temperature and density are estimated. The NH{sub 3} emission is elongated in the same direction of the entire M-0.13-0.08 cloud and has a large velocity gradient along its major axis. Strong NH{sub 3} emission is located in the northern part of the cloud, where a perturbed velocity field and broad line widths are observed. In addition, a new H{sub 2}O maser spot was detected near one of the nonthermal continuum sources. These observational results suggest the physical association between a part of the M-0.13-0.08 molecular cloud and the nonthermal continuum sources in the Sgr A complex. 39 refs.

Molecular gas bar and expanding molecular ring in the nucleus of the spiral galaxy Maffei 2

Aperture synthesis observations of the central 1.5 kpc region of the spiral galaxy Maffei 2 have been made in CO(J = 1-0) line. A central narrow ridge of molecular gas with a size 1000 pc x 200 pc and a ringlike feature with a large noncircular motion (60 km/s) with a size 500 pc x 240 pc have been found. The narrow ridge is interpreted as a bar of molecular gas in shocks generated at the leading edges in the bar potential. The observational results suggest that the ring is an expanding and rotating ring of molecular gas in the plane of the galaxy. The ring may have been formed by a starburst induced by the efficient gas supply in the bar potential. 38 refs.

Digital Spectro-Correlator System for the Atacama Compact Array of the Atacama Large Millimeter/Submillimeter Array

We have developed an FX-architecture digital spectro-correlator for the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array. The correlator is able to simultaneously process four pairs of dual polarization signals with the bandwidth of 2 GHz, which are received by up to sixteen antennas. It can calculate auto- and cross-correlation spectra including cross-polarization in all combinations of all the antennas, and output correlation spectra with flexible spectral configuration such as multiple frequency ranges and multiple frequency resolutions. Its spectral dynamic range is estimated to be higher than 10^4 relative to Tsys from processing results of thermal noise for eight hours with a typical correlator configuration. The sensitivity loss is also confirmed to be 0.9 % with the same configuration. In this paper, we report the detailed design of the correlator and the verification results of the developed hardware.

Superwind-Driven Intense H2 Emission in NGC 6240

We have performed a long-slit K band spectroscopic observation of the luminous infrared galaxy NGC 6240. Spatially extended H2 emission is detected over 3.3 kpc around the two nuclei. The peak position of the H2 v = 1 − 0 S(1) emission in the slit is located ∼ 0. 3 − 0. 4 north of the southern nucleus. It is almost the midpoint between the southern nucleus and the peak position of the 12 CO (J = 1 − 0) emission. Based on the line-ratio analyses, we suggest the excitation mechanism of H2 is pure thermal at

Data analysis environment (DASH2000) for the Subaru telescope

New framework of data analysis system (DASH) has been developed for the SUBARU Telescope. It is designed using object-oriented methodology and adopted a restaurant model. DASH shares the load of CPU and I/O among distributed heterogeneous computers. The distributed object environment of the system is implemented with JAVA and CORBA. DASH has been evaluated by several prototypings. DASH2000 is the latest version, which will be released as the beta version of data analysis system for the SUBARU Telescope.

Distributed storage and control system of Subaru Telescope on the high-speed wide-area connection

In order to achieve an effective operation and research based on data taken by the Subaru Telescope, we installed a satellite storage and analysis system at Mitaka headquarters of Naoj, on March 2002. Data taken by instruments by Subaru Telescope located at the summit of Mauna Kea is transferred to the STN-II system at Hilo base, and satellite system at Mitaka through the OC3 dedicated network link between Hilo and Mitaka. In Japan, an academic research backbone, SuperSINET spans among various universities and institutes with 10Gbps bandwidth at most, and it is easy for astronomers from Japan to access Subaru data through high speed backbone network in Japan. Database on each site, Hilo and Mitaka, are maintained independently, however, all records and history of updating are transferred each other frequently enough to make it possible for recovery in case of any discrepancy among database. Since the round trip time of the light signal between Hawaii and Japan could not be reduced 45msec, we need a special tuning not only for the data transfer between those two node, but also for the remote control sequence.

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.

Prototype of distributed analysis software hierarchy for the Subaru Telescope

We are developing a data reduction and analysis system DASH for efficient data processing of the SUBARU telescope. We adopted CORBA as a distributed object environment and Java for a user interface in the prototype of DASH. Moreover, we introduced a data reduction procedure cube as a kind of visual procedure script.