[Show abstract][Hide abstract] ABSTRACT: We present the result of Subaru Telescope multi-band adaptive optics
observations of the complex gravitationally lensed quasar SDSS J1405+0959,
which is produced by two lensing galaxies. These observations reveal
dramatically enhanced morphological detail, leading to the discovery of an
additional object 0. 26'' from the secondary lensing galaxy, as well as three
collinear clumps located in between the two lensing galaxies. The new object is
likely to be the third quasar image, although the possibility that it is a
galaxy cannot be entirely excluded. If confirmed via future observations, it
would be the first three image lensed quasar produced by two galaxy lenses. In
either case, we show based on gravitational lensing models and photometric
redshift that the collinear clumps represent merging images of a portion of the
quasar host galaxy, with a magnification factor of 15 - 20, depending on the
[Show abstract][Hide abstract] ABSTRACT: We present a spatially resolved imaging analysis of a three-component
gravitationally lensed quasar at z = 3.91, APM 08279+5255, in the L'-
and M'-bands, and a narrow band centered at 3.05 μm using the
188-element adaptive optics system on the Subaru Telescope. The third,
faintest quasar image, component C, has been clearly resolved in all of
these bands for the first time. All of the three components are point
sources in all three bands. No new component, neither a fourth quasar
image nor a lens galaxy, was discovered. The observed bands correspond
to the long-wavelength end of the optical power-law continuum of the
source quasar in its rest frame, and are little contaminated by strong
emission lines like Hα. The measured flux ratio of components C to
B is shown to be constant in all of the observed bands, and its
achromatic nature agrees well with preceding work done at short
near-infrared wavelengths one decade ago. On the other hand, the flux
ratio of components A to B shows an increase from that of past
measurements. This could be ascribed to a microlensing event.
Publications- Astronomical Society of Japan 02/2013; · 2.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present the near-infrared images and spectra of four silhouette disks in
the Orion Nebula Cluster (ONC; M42) and M43 using the Subaru Adaptive Optics
system. While d053-717 and d141-1952 show no water ice feature at 3.1 micron, a
moderately deep (tau~0.7) water ice absorption is detected toward d132-1832 and
d216-0939. Taking into account the water ice so far detected in the silhouette
disks, the critical inclination angle to produce a water ice absorption feature
is confirmed to be 65-75deg. As for d216-0939, the crystallized water ice
profile is exactly the same as in the previous observations taken 3.63 years
ago. If the water ice material is located at 30AU, then the observations
suggest it is uniform at a scale of about 3.5AU.
The Astronomical Journal 10/2012; 144(6). · 4.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report recent development in real-time control system of 188-element
Laser Guide Star Adaptive Optics for Subaru Telescope (Subaru
LGSAO-188). The current status is reported, and plans for improvements
to enhance the performance are reported as well. A major item is to
invoke the optimum gain control, which is being implemented on the data
handling system and to be attached to the real time control system. We
also explain about other new features on the control system including
general response acquisition system as an expansion of response matrix
[Show abstract][Hide abstract] ABSTRACT: A wide-field adaptive optics system based on an adaptive secondary
mirror (ASM) is one of a future plan for the next-generation Subaru
adaptive optics system. The main application of ASM based AO will be a
groundlayer adaptive optics (GLAO) with field-of-view larger than 10 arc
minutes. The high Strehl-ratio of on-source correction by high-order ASM
(expected to be about 1000) and the reduction of emissivity are also
attractive points. In this paper, we report a preliminary result of
simulations for the these applications of ASM to study conceptual design
of the next-generation wide-field Subaru adaptive optics.
[Show abstract][Hide abstract] ABSTRACT: The Subaru adaptive optics system (AO188) is a 188-element curvature
sensor adaptive optics system that is operated in both natural and laser
guide star modes. AO188 is installed at Nasmyth platform of the 8m
Subaru telescope as a facility AO system. The laser guide star mode for
AO188 has been commissioned and offered for use in science operation
since 2011. The performance of AO188 in the laser guide star mode has
been well verified from on-sky data obtained with the infrared camera
and spectrograph (IRCS). In this paper, we describe the operation
procedure and observing efficiency for the laser guide star mode. We
also show the result of the on-sky performance evaluation of AO188 in
the laser guide star mode and the characterization of the laser guide
star, together with the obtained science results.
[Show abstract][Hide abstract] ABSTRACT: The quasar SDSS J133401.39+331534.3 at z = 2.426 is found to be a two-image
gravitationally lensed quasar with the image separation of 0.833. The object is
first identified as a lensed quasar candidate in the Sloan Digital Sky Survey
Quasar Lens Search, and then confirmed as a lensed system from follow-up
observations at the Subaru and University of Hawaii 2.2-meter telescopes. We
estimate the redshift of the lensing galaxy to be 0.557 based on absorption
lines in the quasar spectra as well as the color of the galaxy. In particular,
we observe the system with the Subaru Telescope AO188 adaptive optics with
laser guide star, in order to derive accurate astrometry, which well
demonstrates the usefulness of the laser guide star adaptive optics imaging for
studying strong lens systems. Our mass modeling with improved astrometry
implies that a nearby bright galaxy $\sim 4"$ apart from the lensing galaxy is
likely to affect the lens potential.
The Astrophysical Journal 07/2011; 738. · 6.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A tip/tilt off-load function from AO188 deformable mirror mount to Subaru telescope infrared secondary mirror has been implemented and tested. The function is effective to reduce the influence of strong background pattern at thermal infrared wavelengths. We describe the function and report the test results in this paper.
[Show abstract][Hide abstract] ABSTRACT: The Subaru laser guide star adaptive optics system (AO188) was installed at the Nasmyth focus of the Subaru Telescope on October 2006 and it is in operation with the natural guide star (NGS) mode. The operation of the laser guide star (LGS) mode started on January 2010. A visible low-order wavefront sensor (LOWFS) was built to measure tip-tilt and defocus terms of wavefront by using a single NGS within a 2.7 arcmin diameter field when an LGS is used for high-order wavefront sensing with the 188-element curvature based wavefront sensor. This LOWFS is a 2 × 2 sub-aperture Shack-Hartmann sensor with 16 photon-counting avalanche photodiode (APD) modules. A 4×4-element lenslet array is located after the 2 × 2 sub-aperture Shack-Hartmann lenslet array and it is coupled with the APD modules through optical fibers. The field of view of the LOWFS is 4 arcsec in diameter. It has own guide star acquisition unit, acquisition and pupil cameras, and atmospheric dispersion corrector. We describe the design, construction, and integration of this low-order wavefront sensor.
[Show abstract][Hide abstract] ABSTRACT: We are developing a laser guide star (LGS) system for the 188-elements Adaptive Optics system (AO188) of the Subaru telescope. In this paper we describe the results of the performance tests of the LGS system. The beam that excites sodium atoms at 90 km altitude of the LGS is generated by the following sequence. The source of the beam is a quasi-CW mode locked sum-frequency generating 589 nm laser. This laser beam propagates through a diagnostics system for measuring the wavelength and the beam quality. Then it couples into a solidcore photonic crystal fiber cable for transmitting the beam to a telescope for launching the beam (LLT: Laser Launching Telescope). The output beam from this fiber cable is collimated by the optics mounted on the LLT. This collimated beam is expanded by the LLT and launched into the sky. We executed several engineering observations of the LGS system from 2009 for confirming the performance of all the components in this sequence. We also report the quality of the LGS.
[Show abstract][Hide abstract] ABSTRACT: The current status of commissioning and recent results in performance of Subaru laser guide star adaptive optics system is presented. After the first light using natural guide stars with limited configuration of the system in October 2006, we concentrated to complete a final configuration for a natural guide star to serve AO188 to an open use observation. On sky test with full configurations using natural guide star started in August 2008, and opened to a public one month later. We continuously achieved around 0.6 to 0.7 of Strehl ratio at K band using a bright guide star around 9th to 10th magnitude in R band. We found an unexpectedly large wavefront error in our laser launching telescope. The modification to fix this large wavefront error was made and we resumed the characterization of a laser guide star in February 2009. Finally we obtained a round-shaped laser guide star, whose image size is about 1.2 to 1.6 arcsec under the typical seeing condition. We are in the final phase of commissioning. A diffraction limited image by our AO system using a laser guide star will be obtained in the end of 2010. An open use observation with laser guide star system will start in the middle of 2011.
[Show abstract][Hide abstract] ABSTRACT: Subaru adaptive optics system (AO188) is an 188-elements curvature sensor adaptive optics system that is op-erated in both natural and laser guide star modes. AO188 was installed at Nasmyth platform of the Subaru telescope and it has been successfully operating in the natural guide star mode since October 2008. The perfor-mance of AO188 in the natural guide star mode has been well verified from on-sky data obtained with the infrared camera and spectrograph (IRCS). Under normal seeing condition, AO188 achieves K-band Strehl ratio between 60% and 70% using R = 9.0 magnitude natural guide stars and it works well with faint guide stars down to R = 16.5 magnitude. We measured the FWHM and Strehl ratio of stellar images in globular clusters and found that the isoplanatic angle is approximately 30 arcsec. In this paper, we describe an overview of the operation procedure for AO188, as well as its performance such as angular resolution, Strehl ration, and sensitivity gain for detecting faint objects.
[Show abstract][Hide abstract] ABSTRACT: The image derotator is an integral part of the AO188 System at Subaru Telescope. In this article software control, characterization and integration issues of the image derotator for AO188 System presented. Physical limitations of the current hardware reviewed. Image derotator synchronization, tracking accuracy, and problem solving strategies to achieve requirements presented. It's use in different observation modes for various instruments and interaction with the telescope control system provides status and control functionality. We describe available observation modes along with integration issues. Technical solutions with results of the image derotator performance presented. Further improvements and control software for on-sky observations discussed based on the results obtained during engineering observations. An overview of the requirements, the final control method, and the structure of its control software is shown. Control limitations and accepted solutions that might be useful for development of other instrument's image derotators presented.
[Show abstract][Hide abstract] ABSTRACT: We report recent development in real time control system of Subaru adaptive optics system. The main topic is modification of the real time control system for laser guide star operation. The primary change is appending lower order wave-front sensor. And also, an auxiliary tip-tilt and focus control are appended before higher order waver-front sensor to absorb the perturbation of the laser beam and height of sodium layer. Our implementations using the control gain matrix are introduced thoroughly from the basis of the system design and down to the details. Also, other new function and prospects in the near future will be presented for the cascaded average monitor and the time domain over sampling.
[Show abstract][Hide abstract] ABSTRACT: Adaptive optics system with a laser guide star at Subaru Telescope is under commission. Characteristics of laser guide star, which is produced by all-solid state sum frequency laser at 589 nm, are presented.
[Show abstract][Hide abstract] ABSTRACT: We present new measurements of the diameter of o Ceti (Mira) as a function of wavelength in the 2.2ÃÂ¼m atmospheric window using the adaptive optics system and the infrared camera and spectrograph mounted on the Subaru Telescope. We found that the angular size of the star at the wavelengths of CO and H2O absorption lines were up to twice as large as the continuum photosphere. This size difference is attributable to optically thick CO and H2O molecular layers surrounding the photosphere. This measurement is the first direct differential spectroscopic imaging of stellar extension that resolves individual molecular lines with high spectral-resolution observations. This observation technique is extremely sensitive to differences in spatial profiles at different wavelengths; we show that a difference in diameter much smaller than the point spread function can be measured.
Publications- Astronomical Society of Japan 05/2009; · 2.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present a deep K'-band (2.12 μm) imaging of the 1' × 1' Subaru Super Deep Field (SSDF) taken with the Subaru adaptive optics (AO) system. Total integration time of 26.8 hr results in the limiting magnitude of K' ~ 24.7 (5 σ, 02 aperture) for point sources and K' ~ 23.5 (5 σ, 06 aperture) for galaxies, which is the deepest limit ever achieved in the K' band. The average stellar full width at half-maximum (FWHM) of the co-added image is 018. Based on the photometric measurements of detected galaxies, we obtained the differential galaxy number counts, for the first time, down to K' ~ 25, which is more than 0.5 mag deeper than the previous data. We found that the number count slope d log N/dm is about 0.15 at 22 < K' < 25, which is flatter than the previous data. Therefore, detected galaxies in the SSDF have only negligible contribution to the near-infrared extragalactic background light (EBL), and the discrepancy claimed so far between the diffuse EBL measurements and the estimated EBL from galaxy count integration has become more serious. The size distribution of detected galaxies was obtained down to the area size of less than 0.1 arcsec2, which is less than half of that of the previous data in the K' band. We compared the observed size-magnitude relation with a simple pure luminosity evolution model allowing for intrinsic size evolution and found that a model with no size evolution gives the best fit to the data. It implies that the surface brightness of galaxies at high redshift is not much different from that expected from the size-luminosity relation of present-day galaxies.
The Astrophysical Journal 12/2008; 629(1):29. · 6.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An H2 emission filament is found in close proximity to the unique object KH 15D using the adaptive optics system of the Subaru Telescope. The morphology of the filament, the presence of spectroscopic outflow signatures observed by Hamilton et al., and the detection of extended H2 emission from KH 15D by Deming, Charbonneau, & Harrington suggest that this filament arises from shocked H2 in an outflow. The filament extends about 15'' to the north of KH 15D.
The Astrophysical Journal 12/2008; 601(1):L91. · 6.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present new results of [Fe II] λ1.644 μm spectroscopy toward the jets from HL Tau and RW Aur carried out with the Subaru Telescope combined with the adaptive optics system. We observed the regions within 2''-3'' from the stars with the subarcsecond resolutions of 05 and 02 for HL Tau and RW Aur, respectively. In addition to the strong high-velocity component (HVC) extended along each jet, we detected a blueshifted low-velocity component (LVC) seen as a wing or shoulder of the HVC at each stellar position. The position velocity diagrams of the two objects show a characteristic similar to those of the cold disk wind and X-wind models in that the [Fe II] line width is broad close to the stellar position and narrower at the extended jet. A closer comparison suggests, however, that the disk wind model tends to have too large a line width at the HVC, while the X-wind model has excess redshifted emission at the stellar position. The narrow velocity width with symmetric line profiles of the observed HVC supports an X-wind-type model, while the LVC, located away from the star, favors the presence of a disk wind. The [Fe II] emission shows a gap of 08 for HL Tau and a marked drop of Y ~ -02 for RW Aur between the redshifted jet and the star, which indicate optically thick disks of ~160 and <40 AU in radius, respectively. Part of the Br12 emission of HL Tau originates from the jet itself because its normalized line profile shows a signigicantly large deviation from the normalized continuum in spatial profile.
The Astrophysical Journal 12/2008; 649(2):836. · 6.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present 3 μm spectroscopy of the carbon-rich protoplanetary nebulae IRAS 04296+3429 and IRAS 05341+0852, conducted with the adaptive optics system at the Subaru Telescope. We utilize the nearly diffraction-limited spectroscopy to probe the spatial extent of the hydrocarbon dust emitting zone. We find a hydrocarbon emission core extending up to 100-160 mas from the center of IRAS 04296+3429, corresponding to a physical diameter of 400-640 AU, assuming a distance of 4 kpc. However, we find that IRAS 05341+0852 is not spatially resolved with this instrumentation. The physical extent of these protoplanetary nebulae, along with the reanalyzed data of IRAS 22272+5435 published previously, suggests a correlation between the physical extent of the hydrocarbon dust emission and the spectral evolution of the aliphatic to aromatic features in these post-AGB stars. These measurements represent the first direct test of the proposed chemical synthesis route of carbonaceous dust in the circumstellar environment of evolved stars.
The Astrophysical Journal 12/2008; 662(1):389. · 6.73 Impact Factor