Spectral Sciences Incorporated

About: Spectral Sciences Incorporated is a company organization based out in Burlington, Massachusetts, United States. It is known for research contribution in the topics: Hyperspectral imaging & Radiance. The organization has 114 authors who have published 342 publications receiving 10875 citations.

Atmospheric Compensation of Hyperspectral Data: An Overview and Review of In-Scene and Physics-Based Approaches

Abstract: In this tutorial overview, we examine atmospheric compensation of hyperspectral data in the visible and nearinfrared (VNIR)-short-wave infrared (SWIR) region. The background is discussed, including the motivation for and a brief history of image compensation. Atmospheric characteristics are presented to highlight important optical effects that must be mitigated (i.e., atmospheric absorption and scattering). A full radiative transfer (RT) expression with simplifications is presented, resulting in formulations that are solved in terms of reflectance.

Swift follow-up of IceCube triggers, and implications for the Advanced-LIGO era

Abstract: PAE and JPO acknowledge UK Space Agency support. JMG gratefully acknowledges the support from NASA under award NNH13CH61C.

Visible Spectra of Thruster Plumes from the Space Shuttle Primary Reaction Control System

Abstract: In situ measurements of plume spectra from high-altitude, 870-lb, liquid propellent engine plumes have been obtained from observations of the Space Shuttle's primary reaction control system engines. Spectra were taken in the wavelength range of 350-800 nm with a spectral resolution of 3 nm and a spatial resolution of 10 cm. These spectra show numerous emissions from molecular and atomic species. There is significant variation in the spatial distribution of the emitting species. A survey of the auroral photography experiment (APE) thruster emission data will be given. The data will be compared to a chemical kinetic multizone flowfield model. This model was developed to analyze data from vacuum chamber tests. It incorporates 149 separate reactions and 53 distinct ground and excited state species, but this model is only valid around the exit plane of the thruster. A simplified exhaust plume model, valid for the first few meters of the plume, was then applied to the exit-plane conditions and the results are consistent with all of the major features of the data.

Space Telescope and Optical Reverberation Mapping Project. IX. Velocity–Delay Maps for Broad Emission Lines in NGC 5548

Abstract: In this contribution, we achieve the primary goal of the active galactic nucleus (AGN) STORM campaign by recovering velocity–delay maps for the prominent broad emission lines (Lyα, C iv, He ii, and Hβ) in the spectrum of NGC 5548. These are the most detailed velocity–delay maps ever obtained for an AGN, providing unprecedented information on the geometry, ionization structure, and kinematics of the broad-line region. Virial envelopes enclosing the emission-line responses show that the reverberating gas is bound to the black hole. A stratified ionization structure is evident. The He ii response inside 5–10 lt-day has a broad single-peaked velocity profile. The Lyα, C iv, and Hβ responses extend from inside 2 to outside 20 lt-day, with double peaks at ±2500 km s−1 in the 10–20 lt-day delay range. An incomplete ellipse in the velocity–delay plane is evident in Hβ. We interpret the maps in terms of a Keplerian disk with a well-defined outer rim at R = 20 lt-day. The far-side response is weaker than that from the near side. The line-center delay $\tau =(R/c)(1-\sin i)\approx 5$ days gives the inclination i ≈ 45°. The inferred black hole mass is MBH ≈ 7 × 107 M⊙. In addition to reverberations, the fit residuals confirm that emission-line fluxes are depressed during the "BLR Holiday" identified in previous work. Moreover, a helical "Barber-Pole" pattern, with stripes moving from red to blue across the C iv and Lyα line profiles, suggests azimuthal structure rotating with a 2 yr period that may represent precession or orbital motion of inner-disk structures casting shadows on the emission-line region farther out.

Potential surfaces and dynamics of the O(P3)+H2O(XA111)→OH(XΠ2)+OH(XΠ2) reaction

Abstract: We present global potential energy surfaces for the three lowest triplet states in O(P3)+H2O(XA11) collisions and present results of classical dynamics calculations on the O(P3)+H2O(XA11)→OH(XΠ2)+OH(XΠ2) reaction using these surfaces. The surfaces are spline-based fits of ∼20000 fixed geometry ab initio calculations at the complete-active-space self-consistent field+second-order perturbation theory (CASSCF+MP2) level with a O(4s3p2d1f)/H(3s2p) one electron basis set. Computed rate constants compare well to measurements in the 1000–2500 K range using these surfaces. We also compute the total, rovibrationally resolved, and differential angular cross sections at fixed collision velocities from near threshold at ∼4kms−1 (16.9kcalmol−1 collision energy) to 11kms−1 (122.5kcalmol−1 collision energy), and we compare these computed cross sections to available space-based and laboratory data. A major finding of the present work is that above ∼40kcalmol−1 collision energy rovibrationally excited OH(XΠ2) products are...