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At the University of Hawaii, Institute for Astronomy, we are carrying out several activities to develop CCDs for astronomical observation. In this paper, we report the test results of devices from three CCD manufacturers: Loral, Hamamatsu Photonics and MIT/Lincoln Laboratory.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We report the detection of weak gravitational lensing of faint, distant background galaxies by the rich, X-ray luminous cluster of galaxies MS1054-03 at z=0.83. This is the first measurement of weak lensing by a bona fide cluster at such a high redshift. We detect tangential shear at the 5% - 10% level over a range of radii 50'' < r < 250'' centered on the optical position of the cluster. Two-dimensional mass reconstruction using galaxies with 21.5 < I < 25.5 shows a strong peak which coincides with the peak of the smoothed cluster light distribution. Splitting this sample by magnitude (at I = 23.5) and color (at R-I = 0.7), we find that the brighter and redder subsamples are only very weakly distorted, indicating that the faint blue galaxies (FBG's), which dominate the shear signal, are relatively more distant. The derived cluster mass is quite sensitive to the N(z) for the FBG's. At one extreme, if all the FBG's are at z_s = 3, then the mass within a $0.5h^{-1}$Mpc aperture is $(5.9 \pm 1.24)\times 10^{14}$\h1 $M_\odot$, and the mass-to-light ratio is $M/L_V = 350 \pm 70 h$ in solar units. For $z_s = 1.5$ the derived mass is $\sim$70\% higher and $M/L \simeq 580 h$. If $N(z)$ follows the no evolution model (in shape) then $M/L \simeq 800h$, and if all the FBG's lie at $z_s\la 1$ the required $M/L$ exceeds $1600h$. These data provide clear evidence that large, dense mass concentrations existed at early epochs; that they can be weighed efficiently by weak lensing observations; and that most of the FBG's are at high redshift., Submitted to ApJ, 15 pages (incl 8 figs, 3 of which are plates). Plate images not included, but are available from ftp://hubble.ifa.hawaii.edu/pub/ger/ms1054/ms1054_fig[1,3,5].ps.Z

The MegaCam is a multi-purpose, wide-field, two-color camera being designed for use at the UH 2.2m telescope. The camera will utilize a Rockwell 1024 x 1024 HgCdTe detector array for 1-2.5 micrometers imaging, and a 2048 x 4096 frame-store CCD (2048 x 2048 active area) for optical imaging. The optics are based on a modified Offner relay design with additional lenses to give a 2:1 magnification in the infrared channel for a field of view of 5'.8 x 5'.8 (0.34 arcsec/pixel) using the f/10 telescope secondary, or a scale of 1'.9 x 1'.9 (0.15 arcsec/pixel) at f/31. This design provides a simple, high-throughput, and compact optical layout. A beamsplitter is placed in front of the IR optics at a low angle of incidence to form the optical image at 1:1 magnification on the CCD, for a field of view of 4'.7 x 4'.7 and 1'.5 x 1'.5 at f/10 and f/31, respectively. The optics and filters are to be housed in a LN2-cooled dewar. The CCD and IR arrays will be operated with modified SDSU-design controllers. The user interface will have several modes to make simultaneous optical/IR imaging simple to configure and perform at the telescope.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We describe the design of an ultra-format, 8192 x 8192 pixel CCD mosaic imager under construction for the Mauna Kea Observatory. The mosaic will be built from a 4 x 2 array of 3-edge-buttable 2048 x 4096 15 micrometers pixel CCDs fabricated by Loral Fairchild. We outline the scientific justification for such a mosaic and the technical details of the 3-edge-buttable 2048 x 4096 CCD design. We also present our strategy for imager packaging and subsequent mosaic construction which will result in a mosaic with individual elements that can easily be installed and removed. This particular CCD mosaic is intended for two existing MKO telescopes: the UH 2.2 m and the CFHT 3.6m. In either configuration, the imager will offer an enormous field of view with excellent spatial sampling.

A fast tip-tilt secondary is being implemented on the University of Hawaii 2.2-m telescope, to provide image quality to match the site characteristics of Mauna Kea, and complement the existing wide-field RC secondary.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

CCDs having circular rather than rectilinear symmetry offer some advantages for low-order wavefront sensing. A series of imagers having 24 sectors and 12 radial zones (plus frame store) has been developed. Three different output structures have been utilized in order to investigate low-noise operational limits.

We present the highest redshift detections of resolved Lyman alpha emission, using Hubble Space Telescope/ACS F658N narrowband-imaging data taken in parallel with the Wide Field Camera 3 Early Release Science program in the GOODS CDF-S. We detect Lyman alpha emission from three spectroscopically confirmed z = 4.4 Lyman alpha emitting galaxies (LAEs), more than doubling the sample of LAEs with resolved Lyman alpha emission. Comparing the light distribution between the rest-frame ultraviolet continuum and narrowband images, we investigate the escape of Lyman alpha photons at high redshift. While our data do not support a positional offset between the Lyman alpha and rest-frame ultraviolet (UV) continuum emission, the half-light radii in two out of the three galaxies are significantly larger in Lyman alpha than in the rest-frame UV continuum. This result is confirmed when comparing object sizes in a stack of all objects in both bands. Additionally, the narrowband flux detected with HST is significantly less than observed in similar filters from the ground. These results together imply that the Lyman alpha emission is not strictly confined to its indigenous star-forming regions. Rather, the Lyman alpha emission is more extended, with the missing HST flux likely existing in a diffuse outer halo. This suggests that the radiative transfer of Lyman alpha photons in high-redshift LAEs is complicated, with the interstellar-medium geometry and/or outflows playing a significant role in galaxies at these redshifts.

This paper describes a low cost adaptive optics (AO) instrument that is being built for the f/31 focus of the UH 2.2m telescope. While operating within the low cost constraint, we have tried to maximize the flexibility and usefulness of the instrument, and minimize the impact of the necessary performance compromises. We have used off-the-shelf optical and electronic components wherever possible, and have emphasized simplicity of design throughout the instrument. The UH prototype AO system, on which the 2.2m AO system is based, is described elsewhere, thus the principles of operation of the UH 2.2m instrument will not be described in detail here.

We present the first results from the University of Hawaii Institute for Astronomy project to develop largeformat optical CCD mosaics for the telescopes on Manna Kea. We have constructed two 4096 x 4096 mosaics: both are 2 x 2 arrays of 2-edge abuttable 2048 x 2048 15tm pixel imagers built by Loral Aeronutronics. The first mosaic is constructed using an abuttable package design yielding an array that can be assembled and disassembled using the bestavailable separatelytested quadrants. The second mosaic is formed by packaging a monolithic quad die consisting of four functioning 2048 x 2048 devices from a single wafer. In addition to the mechanical design of the focal plane and dewar we describe the system used to operate the CCDs including the programmable DSP-based CCD controller and our high-speed serial interface into the DSP port of a NeXT computer workstation. We present our initial x-ray and optical test results from the " monolithic mosaic" and our first data from the telescope. 1

A large-format CCD imager to be used in a 2 X 2 mosaic array has been designed and fabricated. Each quadrant is an independent imager of 2048 X 2048 15 micrometers pixels, designed to be edge-butted on two sides. After sawing and mounting the individual dice in custom, buttable packages, the authors assembled a 4096 X 4096 mosaic array measuring more than 61 mm on a side with just 400 microns dead space between imaging areas. With this buttable package design, each quadrant of the mosaic can be separately tested, optimized, and, if necessary, replaced. Also described are smaller 2688 X 512 15 micrometers pixel CCD imagers designed for spectrographic applications that were fabricated using space in the chords of the same 100 mm silicon wafer containing the 2048 X 2048 edge-buttable devices.

We have taken 2.1 μm infrared K'-band images of the Local Group galaxies M31 and M32 and the nearby elliptical galaxy Maffei 1 using a 256×256 pixel HgCdTe infrared array. Measurement of the amplitude of the K'-band surface brightness fluctuations (SBFs) for M31 has enabled us to calibrate the K'-band fluctuations absolute magnitude, M K' =-5.61±0.09, taking M31 to be 0.77 Mpc distant. This agrees with theoretical predictions

We present an IR image of the gravitational lens system MG 0414 + 0534, and IR photometry of PG 1115 + 080, H1413 + 117, and Q1429 - 008. The IR of MG 0414 + 0534 shows a morphology that is similar to the radio and optical morphologies. The object is bright (K-prime = 13.7) and extremely red (I-K-prime = 5.7). MG 0414 + 0534 thus becomes the second radio-selected lens system to have very red optical IR colors. When plotted on a color-magnitude diagram of objects from a radio survey, MG 0414 + 0534 and the other very red system, MG 1131 + 0456, lie near the locus of radio galaxies. We therefore suggest that these systems are lensed high-redshift radio galaxies. In general, lensed radio galaxies should be common among lens systems selected from radio surveys, since a high proportion of radio sources are radio galaxies.

BVRI CCD photometric observations of an extremely rich, X-ray selected cluster of galaxies, Cl 1358+6245, are presented. Spectroscopy of the optically dominant cluster galaxy indicate a redshift of z = 0.32 for the cluster. The photometric catalog contains 322 galaxies measured in at least two colors detected in the CCD field. The cluster luminosity function and color-magnitude diagrams are included. Cl 1358+6245 is extremely rich, contains a compact, concentrated core of galaxies, exhibits the Butcher-Oemler effect with a blue galaxy fraction 0.10 < f b < 0.18, and is X-ray luminous

VRI photometric observations of surface-brightness fluctuation in 13 Virgo Cluster galaxies, M32, and NGC 3379, obtained using an 800 x 800 CCD array on the 4-m telescope at KPNO during March 1989, are reported. The data-reduction techniques are described in detail, and the results are presented in tables and graphs. Particular attention is given to distance estimates derived from the I-band fluctuations: it is shown that NGC 4365 is behind the cluster, while NGC 4468 and NGC 4489 are in the foreground. The average distance to the cluster is found to be 17 + or - 1 Mpc, with H0 = 78 + or - 6 km/sec Mpc; the corresponding values from a direct isochrone calibration are 21 Mpc and 64 + or - 5 km/sec Mpc.

In general, attention to a multitude of details is essential when designing low noise CCD cameras. This paper describes some of the critical details of the MIT X-ray CCD camera design. Special attention is given to those portions of the system which are different from conventional practice in the design of CCD cameras. Furthermore, an attempt has been made to generalize the design so that both optical and X-ray requirements can be satisfied wherever possible. Currently, noise levels of

This paper describes the design and performance of a laboratory instrument for imaging and nondispersive spectroscopy of soft X-rays (300 eV to 10 keV) utilizing a virtual-phase CCD. This instrument has achieved a spatial resolution of 22 microns (limited by pixel size) with an overall array area of 584 x 390 pixels. It has achieved an energy resolution of about 140 eV FWHM for single-pixel Fe-55 X-ray events (5.9 keV) with the CCD operated at -30 C. The CCD has been operated in photon-counting mode at room temperature, and X-ray spectra with an energy resolution of about 450 eV at 5.9 keV have been obtained. The low energy X-ray sensitivity of the CCD also has been demonstrated by detecting carbon K-alpha X-rays (277eV).

This paper describes some of the critical details of the MIT X-ray CCD camera design. Special attention is given to those portions of the system that deviate from conventional practice in the design of CCD cameras. Furthermore, an attempt has been made to generalize the design so that both optical and X-ray requirements can be satisfied whenever possible. Currently, noise levels of less than 8 electrons rms are routinely achieved with this design, and even lower levels (less than 5 electrons) should be realizable.

The use of charge-coupled devices (CCDs) as single photon X-ray detectors has been documented by several research groups. In this paper we describe the design and performance of a powerful laboratory instrument for imaging and non-dispersive spectroscopy of soft X-rays (200 eV to 10 keV) utilizing Texas Instruments TI-4849 virtual-phase CCDs. With this instrument we have achieved a spatial resolution of 22 microns (limited by pixel size) with an overall array area of 584x390 pixels.We have achieved an energy-resolution of -140 eV FWHM for single-pixel Fe55 X-ray events (5.9 keV) with the CCD operated at only -30°C. We have operated the CCD in photon-counting mode at room-temperature and have obtained X-ray spectra with an energy resolution of -450 eV at 5.9 keV. We also have demonstrated the low-energy X-ray sensitivity of the CCD by detecting Carbon K-alpha X-rays (277 eV).

Preliminary results from a project to measure the fluxes of giant stars in M32, NGC 3379, and five Virgo Cluster galaxies are presented. Since the Virgo Cluster galaxies are approximately equidistant, variations in observed fluctuation amplitude from galaxy to galaxy can be ascribed to variations in absolute luminosity of the giant stars in the galaxies. Assuming a distance of 0.72 Mpc for M32 and correcting for the color effect in m-bar, the typical brightness of giant stars, distances of 9 Mpc for NGC 3379 and 14 Mpc for Virgo, accurate to about 10 percent, are derived. This is used to find a Hubble constant of 88 km/s/Mpc. The method can be used to measure m-bar in galaxies at least 40-50 Mpc distant.