Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

Spitzer Local Volume Legacy (LVL) SEDs and physical properties

Abstract: We present the panchromatic spectral energy distributions (SEDs) of the Local Volume Legacy (LVL) survey which consists of 258 nearby galaxies (D <11 Mpc). The wavelength coverage spans the ultraviolet to the infrared (1500 u to 24 µm) which is utilized to derive global physical properties (i.e., star formation rate, stellar mass, internal extinction due to dust.). With these data, we find color-color relationships and correlated trends between observed and physical properties (i.e., optical magnitudes and dust properties, optical color and specific star formation rate, and ultravioletinfrared color and metallicity). The SEDs are binned by different galaxy properties to reveal how each property affects the observed shape of these SEDs. In addition, due to the volume-limited nature of LVL, we utilize the dwarf-dominated galaxy sample to test star formation relationships established with higher-mass galaxy samples. We find good agreement with the star-forming “main-sequence” relationship, but find a systematic deviation in the infrared “main-sequence” at low luminosities. This deviation is attributed to suppressed polycyclic aromatic hydrocarbon (PAH) formation in low metallicity environments and/or the destruction of PAHs in more intense radiation fields occurring near a suggested threshold in sSFR at a value of log(sSF R) » –10.2.

Robust Extraction of Tomographic Information via Randomized Benchmarking

Abstract: We describe how randomized benchmarking can be used to reconstruct the unital part of any trace-preserving quantum map, which in turn is sufficient for the full characterization of any unitary evolution, or more generally, any unital trace-preserving evolution. This approach inherits randomized benchmarking's robustness to preparation, measurement, and gate imperfections, therefore avoiding systematic errors caused by these imperfections. We also extend these techniques to efficiently estimate the average fidelity of a quantum map to unitary maps outside of the Clifford group. The unitaries we consider correspond to large circuits commonly used as building blocks to achieve scalable, universal, and fault-tolerant quantum computation. Hence, we can efficiently verify all such subcomponents of a circuit-based universal quantum computer. In addition, we rigorously bound the time and sampling complexities of randomized benchmarking procedures, proving that the required non-linear estimation problem can be solved efficiently.

Integrated circuit fusing technique

Abstract: A fusing technique whereby a fuse is fabricated upon a substrate by integrated circuit techniques. Three or more layers of chemically dissimilar metals are deposited upon the region where the fuse is to be formed. The top layers are then etched away from the region where the fusible link is to be formed leaving the lower two layers, the top one of which forms the actual fusible link. The lower layer is then etched away leaving the fusible link suspended from the underlying substrate. The current necessary to cause such a fuse to blow is consistent from fuse to fuse since the physical dimensions of the fusible link can accurately be controlled with the integrated circuit techniques used and, since the fusible link is not in contact with the substrate, the rate at which heat is conducted away from the fusible link cannot vary from fuse to fuse. The method is used to advantage in microwave power and oscillator diode circuits such as those used in phased array radar systems and in read only memories and memory reconfiguration applications, as well as other semiconductor fusing applications.

Discovery of Water Maser Emission in Eight AGNs with 70 m Antennas of NASA's Deep Space Network

Abstract: We report the discovery of water maser emission in eight active galactic nuclei (AGNs) with the 70 m NASA Deep Space Network (DSN) antennas at Tidbinbilla, Australia, and Robledo, Spain. The positions of the newly discovered masers, measured with the VLA, are consistent with the optical positions of the host nuclei to within 1 σ (03 radio and 13 optical) and most likely mark the locations of the embedded central engines. The spectra of two sources, NGC 3393 and NGC 5495, display the characteristic spectral signature of emission from an edge-on accretion disk, with orbital velocities of ~600 and ~400 km s-1, respectively. In a survey with DSN facilities of 630 AGNs selected from the NASA Extragalactic Database, we have discovered a total of 15 water maser sources. The resulting incidence rate of maser emission among nearby (vsys < 7000 km s-1) Seyfert 1.8-2.0 and LINER systems is ~10% for a typical rms noise level of ~14 mJy over 1.3 km s-1 spectral channels. As a result of this work, the number of nearby AGNs (vsys < 7000 km s-1) observed with <20 mJy rms noise has increased from 130 to 449.

The ACS LCID Project. IX. Imprints of the Early Universe in the Radial Variation of the Star Formation History of Dwarf Galaxies

Abstract: Based on Hubble Space Telescope observations from the Local Cosmology from Isolated Dwarfs project, we present the star formation histories, as a function of galactocentric radius, of four isolated Local Group dwarf galaxies: two dSph galaxies, Cetus and Tucana, and two transition galaxies (dTrs), LGS-3 and Phoenix. The oldest stellar populations of the dSphs and dTrs are, within the uncertainties, coeval (~13?Gyr) at all galactocentric radii. We find that there are no significative differences between the four galaxies in the fundamental properties (such as the normalized star formation rate or age-metallicity relation) of their outer regions (radii greater than four exponential scale lengths); at large radii, these galaxies consist exclusively of old ( 10.5?Gyr) metal-poor stars. The duration of star formation in the inner regions varies from galaxy to galaxy, and the extended central star formation in the dTrs produces the dichotomy between dSph and dTr galaxy types. The dTr galaxies show prominent radial stellar population gradients: The centers of these galaxies host young ( 1?Gyr) populations, while the age of the last formation event increases smoothly with increasing radius. This contrasts with the two dSph galaxies. Tucana shows a similar, but milder, gradient, but no gradient in age is detected Cetus. For the three galaxies with significant stellar population gradients, the exponential scale length decreases with time. These results are in agreement with outside-in scenarios of dwarf galaxy evolution, in which a quenching of the star formation toward the center occurs as the galaxy runs out of gas in the outskirts.