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First Results from EUNIS-06

The Extreme Ultraviolet Normal-Incidence Spectrograph (EUNIS) sounding rocket experiment successfully completed its first flight on 12 April 2006 from White Sands Missile Range, obtaining 145 science images in each of two wavelength channels. EUNIS is designed to investigate the energetics of the solar corona and hotter transition region through high-resolution imaging spectroscopy with a rapid (2-3 second) cadence. The two independent optical systems of EUNIS simultaneously record spectra over two passbands (170-205 Angstroms and 300-370 Angstroms), each spatially resolved along slit lengths of about 660 arcsec. The longwave channel includes He II 304 Angstroms and strong lines from Fe XI-XVI. The shortwave passband has a sequence of very strong Fe IX-XIII lines. Together, the EUNIS telescopes furnish a wide range of temperature and density diagnostics and enables underflight calibration of instrumental passbands on the SOHO, TRACE, Solar-B and STEREO missions. We present an overview of the science images from the first flight with emphasis on transient phenomena. The target was active region NOAA 10871 and adjacent quiet areas. Spectra were recorded with exposure times as short as 0.1 s, demonstrating that EUNIS is the most sensitive solar EUV spectrograph in operation, with over 100 times the throughput of its predecessor, the Solar Extreme ultraviolet Research Telescope and Spectrograph (SERTS). EUNIS is supported by the NASA Heliophysics Division's Solar & Heliospheric Physics Supporting Research and Technology and Low Cost Access to Space Program.

Rabin, Douglas M.↗

The Importance of High Spatial and Appropriate Spectral Resolution Spectroscopy

Many diverse astronomical sources are resolved with diffraction-limited large telescopes. Application of appropriate dispersion spectroscopy unveils much information on the physics of these objects ranging from gamma ray bursters in host galaxies, star-formation regions and central engines in nearby galaxies, structures in galactic nebulae, resolved binaries with mass exchange, extended winds of massive stars, protoplanetary systems, and comets, asteroids and planets within our own solar system. Active optics and interferometers coupled with spectrographs can provide near-diffraction-limited spectroscopy from the ground but only longward of one micron. Below one micron, and certainly below 6000A, we must turn to space-based large telescopes equipped with spectrographs capable of providing spatially diffraction-limited spectroscopy of astronomical sources. Examples will be presented from the HST/STIS, ground-based and other instruments on science that has been accomplished. Suggestions will be made of what might be possible, and limitations thereof, with future large monolithic, multiple mirror or interferometric telescopes equipped with spectrographs that would be matched to the diffraction limit of the telescope.

Gull, Theodore↗

"Constellation-X and JWST: Concurrent X-ray and Infrared Great Observatories"

Great synergy has been enjoyed between NASA's current Great Observatories and we expect that this will continue in the next decade with the concurrent operation of both Constellation-X and JWST. The great increase in sensitivity offered by these two observatories, working in unison, will be required for a number of key science investigations, several of which we describe in this poster. For instance, although >SO% of the cosmic X-ray background is resolved at 2-8 keV in the deepest Chandra surveys, the peak of the cosmic X-ray background remains largely unexplained (at energies of 8-40 keV). There may be a significant population of obscured (perhaps Compton-thick) AGN that produce this part of the extragalactic background radiation, and Constellation-X's large collecting area and spectroscopic capabilities over the 1-40 keV bandpass will allow determination of the nature of the obscuring material. This obscured nuclear emission is expected to be re-emitted at longer wavelengths and hence mid-infrared (MIR) observations can be crucial to reveal obscured AGN emission. However, current photometric observations in the infrared are limited by contamination from star formation, and sensitive, moderate-to-high resolution IR spectroscopy (provided by JWST) will be required. In addition, the two observatories will make great advances in unraveling the nature of the highest redshift AGN (4 < z < 8; and possibly ~ 8dow)n to Seyfert luminosities and will probe the formation and evolution of galaxy groups and clusters (including important cosmological measurements). This poster describes these science areas and briefly touches upon the role of the various Con-X and JWST instruments in these science investigations.

Hornschemeier, Ann↗

Multi-decade Measurements of the Long-Term Trends of Atmospheric Species by High-Spectral-Resolution Infrared Solar Absorption Spectroscopy

Solar absorption spectra were recorded for the first time in 5 years with the McMath Fourier transform spectrometer at the US National solar Observatory on Kitt Peak in southern Arizona, USA (31.91 N latitude, 111.61 W longitude, 2.09 km altitude). The solar absorption spectra cover 750-1300 and 1850-5000 cm(sup -1) and were recorded on 20 days during March-June 2009. The measurements mark the continuation of a long-term record of atmospheric chemical composition measurements that have been used to quantify seasonal cycles and long-term trends of both tropospheric and stratospheric species from observations that began i 1977. Fits to the measured spectra have been performed, and they indicate the spectra obtained since return to operational status are nearly free of channeling and the instrument line shape function is well reproduced taking into account the measurement parameters. We report updated time series measurements of total columns for six atmospheric species and their analysis for seasonal cycles and long-term trends. An sn example, the time series fit shows a decrease in the annual increase rate i Montreal-Protocol-regulated chlorofluorocarbon CCL2F2 from 1.51 plus or minus 0.38% yr(sup -1) at the beginning of the time span to -1.54 plus or minus 1.28 yr(sup -1) at the end of the time span, 1 sigma, and hence provides evidence for the impact of those regulations on the trend.

Rinsland, Curtis P.↗

First Stars and Galaxies, the Roadmap Ahead: Observation

A complete observational understanding of the first stars and galaxies will require four facilities: JWST, 30m ground-based telescopes, ALMA, and the SKA. Each provides complementary capabilities. JWST is our best hope for looking to very high redshift. 30m-class ground-based telescopes provide sensitivity to the rest-frame ultraviolet with high-resolution imaging and high-resolution NIR spectroscopy, possibly reaching as far as z approx.15. They will also allow us to study stellar populations in nearby galaxies and examine the fossil record of the first stars. ALMA will image the redshifted dust continuum emission from evolving galaxies out to z approx.10. The SKA will do cosmic tomography, mapping the process of reionization.

Gardner, Jonathan P.↗

An Integral-Field Spectrograph for a Terrestrial Planet Finding Mission

We describe a conceptual design for an integral field spectrograph for characterizing exoplanets that we developed for NASA's Terrestrial Planet Finder Coronagraph (TPF-C), although it is equally applicable to an external-occulter mission. The spectrograph fulfills all four scientific objectives of a terrestrial planet finding mission by: (1) Spectrally characterizing the atmospheres of detected planets in search of signatures of habitability or even biological activity; (2) Directly detecting terrestrial planets in the habitable zone around nearby stars; (3) Studying all constituents of a planetary system including terrestrial and giant planets, gas and dust around sun-like stars of different ages and metallicities; (4) Enabling simultaneous, high-spatial-resolution, spectroscopy of all astrophysical sources regardless of central source luminosity, such as AGN's, proplyds, etc.

Heap, Sara R.↗

Latest Progress on the Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

We present the latest progress on building the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument, including testing and calibration of the detectors and development of the imaging and aspect systems. A continental-US test flight is slated for fall 2012. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approx.20. keV to > approx.10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 cu mm. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that ha-.e been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

Shih, Albert Y.↗

Terahertz Radiation Heterodyne Detector Using Two-Dimensional Electron Gas in a GaN Heterostructure

High-resolution submillimeter/terahertz spectroscopy is important for studying atmospheric and interstellar molecular gaseous species. It typically uses heterodyne receivers where an unknown (weak) signal is mixed with a strong signal from the local oscillator (LO) operating at a slightly different frequency. The non-linear mixer devices for this frequency range are unique and are not off-the-shelf commercial products. Three types of THz mixers are commonly used: Schottky diode, superconducting hot-electron bolometer (HEB), and superconductor-insulation-superconductor (SIS) junction. A HEB mixer based on the two-dimensional electron gas (2DEG) formed at the interface of two slightly dissimilar semiconductors was developed. This mixer can operate at temperatures between 100 and 300 K, and thus can be used with just passive radiative cooling available even on small spacecraft.

Karasik, Boris S.↗

The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

The balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approximately 20 keV to greater than approximately 10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of less than 0.1 cubic millimeter. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-centimeter thick tungsten alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 millimeters. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS is scheduled for a continental-US engineering test flight in fall 2013, followed by long or ultra-long duration balloon flights in Antarctica.

Shih, Albert Y.↗

Highly Depleted Ethane and Mildly Depleted Methanol in Comet 21P/Giacobini-Zinner: Application of a New Empirical nu(sub 2) Band Model for CH30H Near 50 K

Infrared spectra of Comet 2lP/Giacobini-Zinner (hereafter 2IP/GZ) were obtained using NIRSPEC at Keck II on UT 2005 June 03, approximately one month before perihelion, that simultaneously measured H2O, C2H6, and CH3OH. For H2O, the production rate of 3.8 x 10(exp 28) molecules / S was consistent with that measured during other apparitions of 21P/GZ retrieved from optical, infrared, and mm-wavelength observations. The water analysis also provided values for rotational temperature (T(sub rot) = 55(epx +3) /-.2 K) and the abundance ratio of ortho- and para-water (3.00 +/-0.15, implying a spin temperature exceeding 50 K). Six Q-branches in the V7 band of C2H6 provided a production rate (5.27 +/- 0.90 x 10(exp 25)/S) that corresponded to an abundance ratio of 0.139 +/- 0.024 % relative to H2O, confirming the previously reported strong depletion of C2H6 from IR observations during the 1998 apparition, and in qualitative agreement with the depletion in C2 known from optical studies. For CH30H, we applied our recently published ab initia model for the v3 band to obtain a rotational temperature (48(exp + 10) / -7 K) consistent with that obtained for H2O. In addition we applied a newly developed empirical model for the CH30H v2 band, and obtained a production rate consistent with that obtained from the v3 band. Combining results from both v2 and v3 bands provided a production rate (47.5 +/- 4.4 x 10(exp 25) / S) that corresponded to an abundance ratio of 1.25 +/- 0.12 % relative to H2O in 21P/GZ. Our study provides the first measure of primary volatile production rates for any Jupiter family comet over multiple apparitions using high resolution IR spectroscopy.

DiSanti, M. A.↗

Greenhouse Gas Concentration Data Recovery Algorithm for a Low Cost, Laser Heterodyne Radiometer

The goal of a coordinated effort between groups at GWU and NASA GSFC is the development of a low-cost, global, surface instrument network that continuously monitors three key carbon cycle gases in the atmospheric column: carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), as well as oxygen (O2) for atmospheric pressure profiles. The network will implement a low-cost, miniaturized, laser heterodyne radiometer (mini-LHR) that has recently been developed at NASA Goddard Space Flight Center. This mini-LHR is designed to operate in tandem with the passive aerosol sensor currently used in AERONET (a well established network of more than 450 ground aerosol monitoring instruments worldwide), and could be rapidly deployed into this established global network. Laser heterodyne radiometry is a well-established technique for detecting weak signals that was adapted from radio receiver technology. Here, a weak light signal, that has undergone absorption by atmospheric components, is mixed with light from a distributed feedback (DFB) telecommunications laser on a single-mode optical fiber. The RF component of the signal is detected on a fast photoreceiver. Scanning the laser through an absorption feature in the infrared, results in a scanned heterodyne signal io the RF. Deconvolution of this signal through the retrieval algorithm allows for the extraction of altitude contributions to the column signal. The retrieval algorithm is based on a spectral simulation program, SpecSyn, developed at GWU for high-resolution infrared spectroscopies. Variations io pressure, temperature, composition, and refractive index through the atmosphere; that are all functions of latitude, longitude, time of day, altitude, etc.; are modeled using algorithms developed in the MODTRAN program developed in part by the US Air Force Research Laboratory. In these calculations the atmosphere is modeled as a series of spherically symmetric shells with boundaries specified at defined altitudes. Temperature, pressure, and species mixing ratios are defined at these boundaries. Between the boundaries, temperature is assumed to vary linearly with altitude while pressure (and thus gas density) vary exponentially. The observed spectrum at the LHR instrument will be the integration of the contributions along this light path. For any absorption measurement the signal at a particular spectral frequency is a linear combination of spectral line contributions from several species. For each species that might absorb in a spectral region, we have pre-calculated its contribution as a function of temperature and pressure. The integrated path absorption spectrum can then by calculated using the initial sun angle (from location, date, and time) and assumptions about pressure and temperature profiles from an atmospheric model. The modeled spectrum is iterated to match the experimental observation using standard multilinear regression techniques. In addition to the layer concentrations, the numerical technique also provides uncertainty estimates for these quantities as well as dependencies on assumptions inherent in the atmospheric models.

Miller, J. Houston↗

Design of Optical/IR Blocking Filters for the Lynx X-Ray Microcalorimeter

The Lynx mission concept, under development ahead of the 2020 Astrophysics Decadal Review, includes the Lynx X-ray Microcalorimeter (LXM) as one of its primary instruments. The LXM uses a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.2 to 15 keV) with exquisite angular resolution. Similar to other x-ray microcalorimeters, the LXM uses a set of blocking filters mounted within the dewar that pass the photons of interest (x-rays) while attenuating the out-of-band long-wavelength radiation. Such filters have been successfully used on previous orbital and suborbital instruments; however, the Lynx science objectives, which emphasize observations in the soft x-ray band (<1keV), pose more challenging requirements on the set of LXM blocking filters. We present an introduction to the design of the LXM optical/IR blocking filters and discuss recent advances in filter capability targeted at LXM. In addition, we briefly describe the external filters and the modulated x-ray sources to be used for onboard detector calibration.

Eckart, Megan E.↗

Extraplanar Emission-Line Gas in NGC 891

We have used spectroscopy and high resolution imaging to study the disk-halo interaction in the edge-on spiral galaxy NGC 891, which is known to have extraplanar gas.

edge-on↗

An X-Ray Spectroscopic Search For Dark Matter And Unidentified Line Signatures In The Perseus Cluster With Hitomi

The reported detection of a 3.5 keV emission signal in the Perseus cluster core by Bulbulet al. (2014, ApJ, 789, 13) was ruled out at high confidence in analysis conducted by Aharonian et al. (2017, ApJ, 837, L15) of X-ray spectra at 5 eV energy resolution obtained with the Hitomi observatory Soft X-ray Spectrometer (SXS). Using the same data, we search the full 2–12 keV SXS energy band for previously unidentified emission and absorption features. No significant unidentified line emission or absorption is found. Line flux upper limits (1σper resolution element) vary with photon energy and assumed intrinsic width, decreasing from∼100 at 2 keV to<10 photons cm−2s−1sr−1over most of the 5–10 keV energy range for a Gaussian line with Doppler broadening of 640 kms−1. Limits for narrower and broader lines have a similar energy dependence and are systematically smaller and larger, respectively. These line flux limits are used to constrain the decay rate of hypothetical dark matter candidates. For the sterile neutrino decay rate, we place new constraints over the mass range of 4–24 keV with mass resolution better than any previous X-ray analysis. Additionally, the accuracy of relevant thermal spectral models and atomic data are evaluated. The Perseus cluster spectra may be described by a composite of multi-temperature thermal and active galactic nuclei (AGN) power-law continua. Superposed on these, a few line emission signals possibly originating from unmodeled atomic processes (including SiXIV and FeXXV)are marginally detected and tabulated. Comparisons with previous X-ray upper limits and future prospects for dark matter searches using high-energy resolution spectroscopy are discussed.

Takayuki Tamura↗

CH3OH and HCN in Interstellar Comet 3I/ATLAS Mapped with the ALMA Atacama Compact Array: Distinct Outgassing Behaviors and a Remarkably High CH3OH/HCN Production Rate Ratio

We report the detection of methanol (CH3OH) toward interstellar comet 3I/ATLAS using the At-acama Compact Array of the Atacama Large Millimeter/Submillimeter Array (ALMA) on UT 2025 August 28, September 18 and 22, and October 1, and of hydrogen cyanide (HCN) on September 12 and 15. These observations spanned pre-perihelion heliocentric distances (r H ) of 2.6 – 1.7 au. The molecules showed outgassing patterns distinct from one another, with HCN production being depleted in the sunward hemisphere of the coma, whereas CH3OH was enhanced in that direction. Statistical analysis of molecular scale lengths in 3I/ATLAS indicated that CH3OH included production from coma sources at Lp > 258 km at 99% confidence. However low signal-to-noise on long baselines, which sample emission on small spatial scales closest to the nucleus, prevented definitively ruling out CH3OH as purely a parent species. In contrast, HCN production was indistinguishable from direct nucleus sublimation. The CH3OH production rate increased sharply from August through October, including an uptick near the inner edge of the H2O sublimation zone at rH = 2 au. Compared to comets measured to date at radio wavelengths, the derived CH3OH/HCN ratios in 3I/ATLAS of 124+30−34 and 79+11−14on September 12 and 15, respectively, are among the most enriched values measured in any comet, surpassed only by anomalous solar system comet C/2016 R2 (PanSTARRS)

Comae↗

Accurate VUV Laboratory Measurements of Fe III Transitions for Astrophysical Applications

We report preliminary measurements of Fe III spectra in the 1150 to 2500 A wavelength interval. Spectra have been recorded with an iron-neon Penning discharge lamp (PDL) between 1600 and 2500 A at Imperial College (IC) using high resolution Fourier (FT) transform spectroscopy. These FT spectrometer measurements were extended beyond 1600 A to 1150 A using high-resolution grating spectroscopy at the National Institute of Standards and Technology (NIST). These recorded spectra represent the first radiometrically calibrated measurements of a doubly-ionized iron-group element spectrum combining the techniques of vacuum ultraviolet FT and grating spectroscopy. The spectral range of the new laboratory measurements corresponds to recent HST/STIS observations of sharp-lined B stars and of Eta Carinae. The new improved atomic data can be applied to abundance studies and diagnostics of astrophysical plasmas.

Blackwell-Whitehead, R. J.↗

Atomic-Level Structure of Mesoporous Hexagonal Boron Nitride Determined by High-Resolution Solid-State Multinuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations

Mesoporous hexagonal boron nitride (p-BN) has received significant attention over the last decade as a promising candidate for water cleaning/pollutant removal and hydrogen storage applications. In this work, high-resolution solid-state NMR spectroscopy and plane-wave density-functional theory (DFT) calculations are used to obtain an atomic-level description of p-BN. 1 H– 15 N or 1 H– 14 N heteronuclear (HETCOR) correlation experiments recorded with either conventional NMR at room temperature or dynamic nuclear polarization surface-enhanced spectroscopy (DNP-SENS) at ca. 100 K reveal NB 2 H, NBH 2 , NBH 3 + species residing on the edges of BN sheets. Ultra-high field 35.2 T 11 B NMR spectroscopy was used to resolve 11 B NMR signals from BN 3 , BN 2 O x (OH) 1–x (x = 0–1), BNO x (OH) 2–x (x = 0–2), BO x (OH) 3–x (x = 0–3), and BO x (OH) 4–x – (x = 0–4). Importantly, 2D 11 B dipolar double-quantum–single-quantum homonuclear correlation spectra reveal that many pore/defect sites are composed of boron oxide/hydroxide clusters connected to the BN framework through BN 2 O units. 1D and 2D 11 B{ 15 N} HETCOR NMR experiments, in addition to plane-wave DFT calculations of nine different structural models, further confirm the assignment of all NMR signals. The detailed structure determination of the pore and edge/defect sites within p-BN should further enable the rational design and development of next-generation p-BN-based materials. In addition, the techniques outlined here should be applicable to determine structure within other porous and/or boron-based materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Capabilities, Performance, and Status of the SOFIA Science Instrument Suite

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory, carrying a 2.5 m telescope onboard a heavily modified Boeing 747SP aircraft. SOFIA is optimized for operation at infrared wavelengths, much of which is obscured for ground-based observatories by atmospheric water vapor. The SOFIA science instrument complement consists of seven instruments: FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope), GREAT (German Receiver for Astronomy at Terahertz Frequencies), HIPO (High-speed Imaging Photometer for Occultations), FLITECAM (First Light Infrared Test Experiment CAMera), FIFI-LS (Far-Infrared Field-Imaging Line Spectrometer), EXES (Echelon-Cross-Echelle Spectrograph), and HAWC (High-resolution Airborne Wideband Camera). FORCAST is a 540 m imager with grism spectroscopy, developed at Cornell University. GREAT is a heterodyne spectrometer providing high-resolution spectroscopy in several bands from 60240 m, developed at the Max Planck Institute for Radio Astronomy. HIPO is a 0.31.1 m imager, developed at Lowell Observatory. FLITECAM is a 15 m wide-field imager with grism spectroscopy, developed at UCLA. FIFI-LS is a 42210 m integral field imaging grating spectrometer, developed at the University of Stuttgart. EXES is a 528 m high-resolution spectrograph, developed at UC Davis and NASA ARC. HAWC is a 50240 m imager, developed at the University of Chicago, and undergoing an upgrade at JPL to add polarimetry capability and substantially larger GSFC detectors. We describe the capabilities, performance, and status of each instrument, highlighting science results obtained using FORCAST, GREAT, and HIPO during SOFIA Early Science observations conducted in 2011.

SOFIA↗