30 research outputs found
Design and performance of a F/#-conversion microlens for Prime Focus Spectrograph at Subaru Telescope
The PFS is a multi-object spectrograph fed by 2394 fibers at the prime focus
of Subaru telescope. Since the F/# at the prime focus is too fast for the
spectrograph, we designed a small concave-plano negative lens to be attached to
the tip of each fiber that converts the telescope beam (F/2.2) to F/2.8. We
optimized the lens to maximize the number of rays that can be confined inside
F/2.8 while maintaining a 1.28 magnification. The microlenses are manufactured
by glass molding, and an ultra-broadband AR coating (<1.5% for lambda=0.38-1.26
um) will be applied to the front surface.Comment: 7 pages, 8 figures, SPIE201
Are Two z~6 Quasars Gravitationally Lensed ?
Several high-z (z > 5.7) quasars have been found in the course of Sloan
Digital Sky Survey. The presence of such very high-z quasars is expected to
give constraints on early structure formation. On one hand, it is suggested
that these most luminous objects at high redshift are biased toward the highly
magnified objects by gravitational lensing. To clarify the effect of
gravitational lensing on the high-z quasars, we began the imaging survey of
intervening lensing galaxies. Indeed our previous optical image showed that
SDSSp J104433.04+012502.2 at z=5.74 is gravitationally magnified by a factor 2.
In this paper, we report our new optical imaging of other two high-z quasars,
SDSSp J103027.10+052455.0 at z=6.28 and SDSSp J130608.26+035626.3 at z=5.99.
Since we find neither intervening galaxy nor counter image with i^{\prime} <
25.4-25.8 around each quasar, we conclude that they are not strongly magnified
regardless that a lens galaxy is dusty.Comment: 10 pages, 8 figures, Accepted for PAS
Reddening and Distance of the Local Group Starburst Galaxy IC 10
We estimate the reddening and distance of the nearest starburst galaxy IC 10
using deep near infrared photometry obtained with the Multi-Object
InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope. We estimate
the foreground reddening toward IC 10 using photometry of IC 10 from the
Local Group Survey, obtaining mag. We derive the total
reddening including the internal reddening, mag, using
photometry of early-type stars in IC 10 and comparing
photometry of red giant branch stars in IC 10 and the SMC. Using the 2MASS
point source catalog of 20 Galactic globular clusters, we derive a relation
between the metallicity [Fe/H] and the slope of the red giant branch
in the color-magnitude diagram. The mean metallicity of the
red giant branch stars in IC 10 is estimated to be
[Fe/H]. The magnitude of the tip of the red giant branch
(TRGB) of IC 10 in the band is measured to be
. Based on the TRGB method, we estimate the distance
modulus of IC 10 to be , corresponding to the distance of kpc. This
confirms that IC 10 is a member of the Local Group.Comment: 35 pages, 11 figures, To appear in the Astrophysical Journal, 200
Metrology Camera System of Prime Focus Spectrograph for Subaru Telescope
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber
spectrograph designed for the prime focus of the 8.2m Subaru telescope. The
metrology camera system of PFS serves as the optical encoder of the COBRA fiber
motors for the configuring of fibers. The 380mm diameter aperture metrology
camera will locate at the Cassegrain focus of Subaru telescope to cover the
whole focal plane with one 50M pixel Canon CMOS sensor. The metrology camera is
designed to provide the fiber position information within 5{\mu}m error over
the 45cm focal plane. The positions of all fibers can be obtained within 1s
after the exposure is finished. This enables the overall fiber configuration to
be less than 2 minutes.Comment: 10 pages, 12 figures, SPIE Astronomical Telescopes and
Instrumentation 201
The Subaru Deep Field Project: Lyman Emitters at Redshift of 6.6
We present new results of a deep optical imaging survey using a narrowband
filter () centered at 9196 \AA ~ together with , ,
, , and broadband filters in the sky area of the Subaru
Deep Field which has been promoted as one of legacy programs of the 8.2m Subaru
Telescope. We obtained a photometric sample of 58 Ly emitter candidates
at 6.5 -- 6.6 among strong -excess () objects together with a color criterion of . We then obtained optical spectra of 20 objects in our -excess
sample and identified at least nine Ly emitters at -- 6.6
including the two emitters reported by Kodaira et al. (2003). Since our
Ly emitter candidates are free from strong amplification of
gravitational lensing, we are able to discuss their observational properties
from a statistical point of view. Based on these new results, we obtain a lower
limit of the star formation rate density of yr Mpc at , being
consistent with our previous estimate. We discuss the nature of star-formation
activity in galaxies beyond .Comment: 49 pages, 16 figures, PASJ, Vol. 57, No. 1, in pres
Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)
We describe the conceptual design of the camera cryostats, detectors, and
detector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS)
being developed for the Subaru telescope. The SuMIRe PFS will consist of four
identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic
positioner at the prime focus. Each spectrograph will have three channels
covering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA},
and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in each
channel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pair
of Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4K
x 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel,
mercury-cadmium-telluride sensor with substrate removed for short-wavelength
response and a 1.7 um cutoff will be used. Identical detector geometry and a
nearly identical optical design allow for a common cryostat design with the
only notable difference being the need for a cold radiation shield in the IR
camera to mitigate thermal background. This paper describes the details of the
cryostat design and cooling scheme, relevant thermal considerations and
analysis, and discusses the detectors and detector readout electronics
The Taiwan ECDFS Near-Infrared Survey: Very Bright End of the Luminosity Function at z>7
The primary goal of the Taiwan ECDFS Near-Infrared Survey (TENIS) is to find
well screened galaxy candidates at z>7 (z' dropout) in the Extended Chandra
Deep Field-South (ECDFS). To this end, TENIS provides relatively deep J and Ks
data (~25.3 ABmag, 5-sigma) for an area of 0.5*0.5 degree. Leveraged with
existing data at mid-infrared to optical wavelengths, this allows us to screen
for the most luminous high-z objects, which are rare and thus require a survey
over a large field to be found. We introduce new color selection criteria to
select a z>7 sample with minimal contaminations from low-z galaxies and
Galactic cool stars; to reduce confusion in the relatively low angular
resolution IRAC images, we introduce a novel deconvolution method to measure
the IRAC fluxes of individual sources. Illustrating perhaps the effectiveness
at which we screen out interlopers, we find only one z>7 candidate, TENIS-ZD1.
The candidate has a weighted z_phot of 7.8, and its colors and luminosity
indicate a young (45M years old) starburst galaxy with a stellar mass of
3.2*10^10 M_sun. The result matches with the observational luminosity function
analysis and the semi-analytic simulation result based on the Millennium
Simulations, which may over predict the volume density for high-z massive
galaxies. The existence of TENIS-ZD1, if confirmed spectroscopically to be at
z>7, therefore poses a challenge to current theoretical models for how so much
mass can accumulate in a galaxy at such a high redshift.Comment: 14 pages, 11 figures, ApJ accepte
Current Performance and On-Going Improvements of the 8.2 m Subaru Telescope
An overview of the current status of the 8.2 m 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.Comment: 18 pages (17 pages in published version), 29 figures (GIF format),
This is the version before the galley proo
Prime Focus Instrument of Prime Focus Spectrograph for Subaru Telescope
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber
spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will
cover 1.3 degree diameter field with 2394 fibers to complement the imaging
capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime
Focus Instrument (PFI) provides the interface with the top structure of Subaru
telescope and also accommodates the optical bench in which Cobra fiber
positioners are located. In addition, the acquisition and guiding (A&G)
cameras, the optical fiber positioner system, the cable wrapper, the fiducial
fibers, illuminator, and viewer, the field element, and the telemetry system
are located inside the PFI. The mechanical structure of the PFI was designed
with special care such that its deflections sufficiently match those of the HSC
Wide Field Corrector (WFC) so the fibers will stay on targets over the course
of the observations within the required accuracy.Comment: 9 pages, 7 figures, SPIE Astronomical Telescopes and Instrumentation
201