Operation of the University of Hawaii 2.2M telescope on Mauna Kea

NASA's planetary astronomy program provides part of the funding for the 2.2 meter telescope. The parameters for time on the telescope are laid out. A major instrumental highlight has been the commissioning of a 256 x 256 near infrared camera which uses a Rockwell NICMOS-3 array. At the f/10 focus, image scales of 0.37 and 0.75 arcsec/pixel are available. A new, high quantum efficiency Tektronix 1024 x 1024 CCD saw first light on the telescope in 1991, and was available regularly from April 1991. Data from both of these detectors are transmitted directly to the Sun workstation for immediate analysis by the observers. The autoguider software was enhanced to permit guided tracking on objects have nonsideral motions (i.e., solar system objects)

Wide field imaging of solar system objects with an 8192 x 8192 CCD mosaic

As part of this program, we successfully completed the construction of the world's largest CCD camera, an 8192 x 8192 CCD mosaic. The system employs 8 2K x 4K 3-edge buttable CCDs arranged in a 2 x 4 chip mosaic. The focal plane has small gaps (less than 1 mm) between mosaic elements and measures over 120 mm x 120 mm. The initial set of frontside illuminated CCDs were developed with Loral-Fairchild in a custom foundry run. The initial lots yielded of order 20 to 25 functional devices, of which we selected the best eight for inclusion for the camera. We have designed a custom 3-edge-buttable package that ensures the CCD dies are mounted flat to plus or minus 10 microns over the entire area of the mosaic. The mosaic camera system consists of eight separate readout signal chains controlled by two independent DSP microcontrollers. These are in turn interfaced to a Sun Sparc-10 workstation through two high speed fiber optic interfaces. The system saw first-light on the Canada-France-Hawaii Telescope on Mauna Kea in March 1995. First-light on the University of Hawaii 2.2-M Telescope on Mauna Kea was in July 1995. Both runs were quite successful. A sample of some of the early science from the first light run is reported in the publication, 'Observations of Weak Lensing in Clusters with an 8192 x 8192 CCD Mosaic Camera'

Operation of the University of Hawaii 2.2 M Telescope on Mauna KEA

During the period October 5, 1993-October 31, 1997, operation of the University of Hawaii's 2.2-meter telescope was partially funded by NASA Planetary Astronomy Program. During the grant period, the fraction of observing time devoted to studies of solar system objects (e.g., planets, planetary satellites, asteroids, and comets) was approximately 24% (i.e., it exceeded the fractional funding provided by this NASA grant). The number of nights allocated to planetary observing time is summarized. Proposals for use of the solar system observing time coming from within and outside the University of Hawaii competed for this observing time on an equal basis; applications were judged on scientific merit by a time allocation committee at the University of Hawaii

Overview of the SAPHIRA Detector for AO Applications

We discuss some of the unique details of the operation and behavior of Leonardo SAPHIRA detectors, particularly in relation to their usage for adaptive optics wavefront sensing. SAPHIRA detectors are 320$\times$256@24 $\mu$m pixel HgCdTe linear avalanche photodiode arrays and are sensitive to 0.8-2.5 $\mu m$ light. SAPHIRA arrays permit global or line-by-line resets, of the entire detector or just subarrays of it, and the order in which pixels are reset and read enable several readout schemes. We discuss three readout modes, the benefits, drawbacks, and noise sources of each, and the observational modes for which each is optimal. We describe the ability of the detector to read subarrays for increased frame rates, and finally clarify the differences between the avalanche gain (which is user-adjustable) and the charge gain (which is not).Comment: 13 pages, 4 figures, 2 tables, accepted to JATI

Discovery of a Gravitationally Lensed Quasar from the Sloan Digital Sky Survey: SDSS J133222.62+034739.9

We report the discovery of the two-image gravitationally lensed quasar SDSS J133222.62+034739.9 (SDSS J1332+0347) with an image separation of Delta_theta=1.14". This system consists of a source quasar at z_s=1.445 and a lens galaxy at z_l=0.191. The agreement of the luminosity, ellipticity and position angle of the lens galaxy with those expected from lens model confirms the lensing hypothesis.Comment: 16 pages, 4 figures, the Astronomical Journal accepte

Two New Gravitationally Lensed Double Quasars from the Sloan Digital Sky Survey

We report the discoveries of the two-image gravitationally lensed quasars, SDSS J0746+4403 and SDSS J1406+6126, selected from the Sloan Digital Sky Survey (SDSS). SDSS J0746+4403, which will be included in our lens sample for statistics and cosmology, has a source redshift of z_s=2.00, an estimated lens redshift of z_l~0.3, and an image separation of 1.08". SDSS J1406+6126 has a source redshift of z_s=2.13, a spectroscopically measured lens redshift of z_l=0.27, and an image separation of 1.98". We find that the two quasar images of SDSS J1406+6126 have different intervening MgII absorption strengths, which are suggestive of large variations of absorbers on kpc scales. The positions and fluxes of both the lensed quasar systems are easily reproduced by simple mass models with reasonable parameter values. These objects bring to 18 the number of lensed quasars that have been discovered from the SDSS data.Comment: 25 pages, 6 figures, The Astronomical Journal accepte

X-ray Insights Into Interpreting CIV Blueshifts and Optical/UV Continua

We present 0.5-8.0 keV Chandra observations of six bright quasars that represent extrema in quasar emission-line properties -- three quasars each with small and large blueshifts of the CIV emission line with respect to the systemic redshift of the quasars. Supplemented with seven archival Chandra observations of quasars that met our selection criteria, we investigate the origin of this emission-line phenomenon in the general context of the structure of quasars. We find that the quasars with the largest CIV blueshifts show evidence, from joint-spectral fitting, for intrinsic X-ray absorption (N_H ~ 10^22 cm^-2). Given the lack of accompanying CIV absorption, this gas is likely to be highly ionized, and may be identified with the shielding gas in the disk-wind paradigm. Furthermore, we find evidence for a correlation of alpha_uv, the ultraviolet spectral index, with the hardness of the X-ray continuum; an analysis of independent Bright Quasar Survey data from the literature supports this conclusion. This result points to intrinsically red quasars having systematically flatter hard X-ray continua without evidence for X-ray absorption. We speculate on the origins of these correlations of X-ray properties with both CIV blueshift and alpha_uv and discuss the implications for models of quasar structure.Comment: 9 figs, 25 pages, AASTeX; accepted for publication in A

The Sloan Digital Sky Survey Reverberation Mapping Project: Ensemble Spectroscopic Variability of Quasar Broad Emission Lines

We explore the variability of quasars in the MgII and Hbeta broad emission lines and UV/optical continuum emission using the Sloan Digital Sky Survey Reverberation Mapping project (SDSS-RM). This is the largest spectroscopic study of quasar variability to date: our study includes 29 spectroscopic epochs from SDSS-RM over $6$ months, containing 357 quasars with MgII and 41 quasars with Hbeta . On longer timescales, the study is also supplemented with two-epoch data from SDSS-I/II. The SDSS-I/II data include an additional $2854$ quasars with MgII and 572 quasars with Hbeta. The MgII emission line is significantly variable ($\Delta f/f$ 10% on 100-day timescales), a necessary prerequisite for its use for reverberation mapping studies. The data also confirm that continuum variability increases with timescale and decreases with luminosity, and the continuum light curves are consistent with a damped random-walk model on rest-frame timescales of $\gtrsim 5$ days. We compare the emission-line and continuum variability to investigate the structure of the broad-line region. Broad-line variability shows a shallower increase with timescale compared to the continuum emission, demonstrating that the broad-line transfer function is not a $\delta$-function. Hbeta is more variable than MgII (roughly by a factor of $1.5$), suggesting different excitation mechanisms, optical depths and/or geometrical configuration for each emission line. The ensemble spectroscopic variability measurements enabled by the SDSS-RM project have important consequences for future studies of reverberation mapping and black hole mass estimation of $1<z<2$ quasars.Comment: 20 pages, 25 figures. ApJ accepted: minor revisions following referee repor

Discovery of Two Gravitationally Lensed Quasars with Image Separations of 3 Arcseconds from the Sloan Digital Sky Survey

We report the discovery of two doubly-imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and 1.789 and with image separations of 2.86'' and 2.90'', respectively. The objects were selected as lens candidates from the Sloan Digital Sky Survey (SDSS). Based on the identical nature of the spectra of the two quasars in each pair and the identification of the lens galaxies, we conclude that the objects are gravitational lenses. The lenses are complicated; in both systems there are several galaxies in the fields very close to the quasars, in addition to the lens galaxies themselves. The lens modeling implies that these nearby galaxies contribute significantly to the lens potentials. On larger scales, we have detected an enhancement in the galaxy density near SDSS J100128.61+502756.9. The number of lenses with image separation of ~3'' in the SDSS already exceeds the prediction of simple theoretical models based on the standard Lambda-dominated cosmology and observed velocity function of galaxies.Comment: 24 pages, 9 figures, accepted for publication in Ap