Bryan N. Dorland

IDENTIFICATION OF 1.4 MILLION ACTIVE GALACTIC NUCLEI IN THE MID-INFRARED USING WISE DATA

Abstract : We present an all-sky sample of approx. equal 1.4 million active galactic nuclei (AGNs) meeting a two-color infrared photometric selection criteria for AGNs as applied to sources from the Wide-field Infrared Survey Explorer final catalog release (AllWISE). We assess the spatial distribution and optical properties of our sample and find that the results are consistent with expectations for AGNs. These sources have a mean density of approx. equal 38 AGNs per square degree on the sky, and their apparent magnitude distribution peaks at g approx. equal 20, extending to objects as faint as g approx. equal 26. We test the AGN selection criteria against a large sample of optically identified stars and determine the leakage (that is, the probability that a star detected in an optical survey will be misidentified as a quasi-stellar object (QSO) in our sample) rate to be less than or = 4.0 x 10(exp -5). We conclude that our sample contains almost no optically identified stars (less than or = 0.041%), making this sample highly promising for future celestial reference frame work as it significantly increases the number of all-sky, compact extragalactic objects. We further compare our sample to catalogs of known AGNs/QSOs and find a completeness value of greater than or approx. 84% (that is, the probability of correctly identifying a known AGN/QSO is at least 84%) for AGNs brighter than a limiting magnitude of R less than or approx. 19. Our sample includes approximately 1.1 million previously uncataloged AGNs.

Forced libration of tidally synchronized planets and moons

Tidal dissipation of kinetic energy, when it is strong enough, tends to synchronize the rotation of planets and moons with the mean orbital motion, or drive it into long-term stable spin-orbit resonances. As the orbital motion undergoes periodic acceleration due to a finite orbital eccentricity, the spin rate oscillates around the equilibrium mean value too, giving rise to the forced, or eccentricity-driven, librations. Both the shape and amplitude of forced librations of synchronous viscoelastic planets and moons are defined by a combination of two different types of perturbative torque, the tidal torque and the triaxial torque. Consequently, forced librations can be tidally dominated (e.g., Io and possibly Titan) or deformation-dominated (e.g., the Moon) depending on a set of orbital, rheological, and other physical parameters. With small eccentricities, for the former kind, the largest term in the libration angle can be minus cosine of the mean anomaly, whereas for the latter kind, it is minus sine of the mean anomaly. The shape and the amplitude of tidal forced librations determine the rate of orbital evolution of synchronous planets and moons, i.e., the rate of dissipative damping of semimajor axis and eccentricity. The known super-Earth exoplanets can exhibit both kinds of libration, or a mixture thereof, depending on, for example, the effective Maxwell time of their rigid mantles. Our approach can be extended to estimate the amplitudes of other libration harmonics, as well as the forced libration in non-synchronous spin-orbit resonances.

Laboratory and sky testing results for the TIS H4RG-10 4k x 4k 10-micron visible CMOS-hybrid detector

We present both laboratory and telescope testing results describing the performance of the H4RG-10 CMOS-Hybrid detector. The H4RG-10 is the largest visible hybrid array currently in existence and shows great potential for use in future space missions. We report read noise, dark current, pixel connectivity, persistence, and inter-pixel capacitance measurements for the temperature range 110-240 K. We report on quantitative astrometric and qualitative photometric performance of the instrument based on observations made at USNOs Flagstaff Station observatory and establish an upper limit to the astrometric performance of the detector. We discuss additional testing and future work associated with improving detector performance.

Realization and application of a 111 million pixel backside-illuminated detector and camera

A full-wafer, 10,580 × 10,560 pixel (95 × 95 mm) CCD was designed and tested at Semiconductor Technology Associates (STA) with 9 μm square pixels and 16 outputs. The chip was successfully fabricated in 2006 at DALSA and some performance results are presented here. This program was funded by the Office of Naval Research through a Small Business Innovation in Research (SBIR) program requested by the U.S. Naval Observatory for its next generation astrometric sky survey programs. Using Leach electronics, low read-noise output of the 111 million pixels requires 16 seconds at 0.9 MHz. Alternative electronics developed at STA allow readout at 20 MHz. Some modifications of the design to include anti-blooming features, a larger number of outputs, and use of p-channel material for space applications are discussed.

UrHip PROPER MOTION CATALOG

Proper motions are computed and collected in a catalog using the Hipparcos positions (epoch 1991.25) and URAT1 positions (epoch 2012.3–2014.6). The goal is to obtain a significant improvement on the proper motion accuracy of single stars in the northern hemisphere, and to identify new astrometric binaries perturbed by orbital motion. For binaries and multiple systems, the longer baseline of Tycho2 (~100 years) makes it more reliable despite its larger formal uncertainties. The resulting proper motions obtained for 67,340 stars have a consequent gain in accuracy by a factor of ~3 compared to Hipparcos. Comparison between UrHip and Hipparcos shows that they are reasonably close, but also reveals stars with large discrepant proper motions, a fraction of which are potential binary candidates.

Initial laboratory and sky testing results for the second generation H4RG-10 4k x 4k, 10 micron visible CMOS-Hybrid detector

We present the initial performance test results for the H4RG-10 (A2), the second generation of the H4RG-10 visible CMOS-Hybrid Sensor Chip Assembly (SCA). The first science grade H4RG-10 (A2), delivered in 2009, is an evolution of the first generation A1, first delivered and tested in 2007. The H4RG-10 is primarily intended for ground- and space-based astronomical applications. Our evaluation focused on the performance parameters as they are related to astrometric applications. We find that the A2 SCA shows high pixel interconnect (99.6%), and low read noise (10-15 e- RMS) when operated at high speeds, consistent with A1 results. Most importantly, the H4RG-10 (A2) shows a dramatic improvement in dark current vs. the A1, with a two order of magnitude reduction in mean dark level and significantly reduced hot pixel population below 200 K.

CORRELATED AND ZONAL ERRORS OF GLOBAL ASTROMETRIC MISSIONS: A SPHERICAL HARMONIC SOLUTION

We propose a computer-efficient and accurate method of estimating spatially correlated errors in astrometric positions, parallaxes, and proper motions obtained by space- and ground-based astrometry missions. In our method, the simulated observational equations are set up and solved for the coefficients of scalar and vector spherical harmonics representing the output errors rather than for individual objects in the output catalog. Both accidental and systematic correlated errors of astrometric parameters can be accurately estimated. The method is demonstrated on the example of the JMAPS mission, but can be used for other projects in space astrometry, such as SIM or JASMINE.

Interpixel crosstalk in Teledyne Imaging Sensors H4RG-10 detectors.

Complementary metal-oxide semiconductor (CMOS)-hybrid arrays have become competitive optical detectors for use in ground- and space-based astronomy. Interpixel capacitance (IPC) is one source of error that appears in most CMOS arrays. In this paper, we use a single-pixel-reset method to model IPC. We combine this IPC model with a model for charge diffusion to estimate the total crosstalk on H4RG-10 arrays. Finally, we compare our model results to 55Fe data obtained using an astrometric camera built to test the H4RG-10 B0 generation detectors.

Radiometric and noise characteristics of SI-1920HD cameras built from the AltaSens ProCamHD 3560 FPA

This paper presents the radiometric and noise characteristics of 12-bit SI-1920HD cameras built from the AltaSens ProCamHD 3560 FPA as a function of integration time and temperature. Our measurements are for two integration time regions: 1 to 50 millisecond, which is standard for video operation; and 1 to 240 seconds, of possible use for stellar observations. For 1 to 50 millisecond integration times, the cameras are extremely linear with a Gaussian-like dark frame. As we increased to seconds-long integration times, the camera initially remains radiometrically linear, but develops a dark frame with the vast majority of pixels at dn=5. Further increases in integration time eventually result in a saturated dark frame with all pixels at dn=4095. Reducing the operating temperature to -7.2°C increased the integration times at which the cameras two transitions occur by a factor of 20. The calibration parameters determined from our measurements were applied to the image data collected by Dorland et al. (these proceedings).

Astrometric sky testing results for the TIS 5-micron 3T-class CMOS detector

CMOS-based focal planes have many potential advantages over CCDs for use in space for star mapping/star tracking applications. These include more flexible readout circuitry and improved radiation tolerance. There are also weaknesses, including noise performance, quantum efficiency, and potential systematics introduced by the presence of circuitry on the photosensitive side of the detector. In this paper, we measure the effects of these sources of error on centroiding and photometry for the HDTV (1k x 2k) SI-1920HD camera by observing stellar reference fields using USNOs 8-inch Twin Astrograph telescope in Flagstaff, AZ. This camera serves as an archetype for the entire family of related TIS detectors, including the 3k x 4k V12M and the 7.6k x 7.6k V59M. We determine an upper limit for the astrometric centroiding performance for this class of detector to be ~1/30th of a pixel. There are indications that better performance may be possible if improvements are made to the temperature control system used for this first set of observations.