Morphology and Kinematics of Filaments in the Serpens and Perseus Molecular Clouds

We present H13CO+ (J=1-0) and HNC (J=1-0) maps of regions in Serpens South, Serpens Main and NGC 1333 containing filaments. We also observe the Serpens regions using H13CN (J=1-0). These dense gas tracer molecular line observations carried out with CARMA have an angular resolution of ~7", a spectral resolution of ~0.16 km/s and a sensitivity of 50-100 mJy/beam. Although the large scale structure compares well with the Herschel dust continuum maps, we resolve finer structure within the filaments identified by Herschel. The H13CO+ emission distribution agrees with the existing CARMA N2H+ (J=1-0) maps; so they trace the same morphology and kinematics of the filaments. The H13CO+ maps additionally reveal that many regions have multiple structures partially overlapping in the line-of-sight. In two regions, the velocity differences are as high as 1.4 m/s. We identify 8 filamentary structures having typical widths of 0.03-0.08 pc in these tracers. At least 50% of the filamentary structures have distinct velocity gradients perpendicular to their major axis with average values in the range 4-10 km/s/pc. These findings are in support of the theoretical models of filament formation by 2-D inflow in the shock layer created by colliding turbulent cells. We also find evidence of velocity gradients along the length of two filamentary structures; the gradients suggest that these filaments are inflowing towards the cloud core.Comment: 30 pages, 16 figure

Commissioning and performance results of the WFIRST/PISCES integral field spectrograph

The Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a high contrast integral field spectrograph (IFS) whose design was driven by WFIRST coronagraph instrument requirements. We present commissioning and operational results using PISCES as a camera on the High Contrast Imaging Testbed at JPL. PISCES has demonstrated ability to achieve high contrast spectral retrieval with flight-like data reduction and analysis techniques.Comment: Author's copy - Proceedings of SPIE Volume 10400. Citation to SPIE proceedings volume will be added when availabl

Simulating the WFIRST coronagraph Integral Field Spectrograph

A primary goal of direct imaging techniques is to spectrally characterize the atmospheres of planets around other stars at extremely high contrast levels. To achieve this goal, coronagraphic instruments have favored integral field spectrographs (IFS) as the science cameras to disperse the entire search area at once and obtain spectra at each location, since the planet position is not known a priori. These spectrographs are useful against confusion from speckles and background objects, and can also help in the speckle subtraction and wavefront control stages of the coronagraphic observation. We present a software package, the Coronagraph and Rapid Imaging Spectrograph in Python (crispy) to simulate the IFS of the WFIRST Coronagraph Instrument (CGI). The software propagates input science cubes using spatially and spectrally resolved coronagraphic focal plane cubes, transforms them into IFS detector maps and ultimately reconstructs the spatio-spectral input scene as a 3D datacube. Simulated IFS cubes can be used to test data extraction techniques, refine sensitivity analyses and carry out design trade studies of the flight CGI-IFS instrument. crispy is a publicly available Python package and can be adapted to other IFS designs.Comment: 15 page

Finding the Needles in the Haystacks: High-Fidelity Models of the Modern and Archean Solar System for Simulating Exoplanet Observations

We present two state-of-the-art models of the solar system, one corresponding to the present day and one to the Archean Eon 3.5 billion years ago. Each model contains spatial and spectral information for the star, the planets, and the interplanetary dust, extending to 50 AU from the sun and covering the wavelength range 0.3 to 2.5 micron. In addition, we created a spectral image cube representative of the astronomical backgrounds that will be seen behind deep observations of extrasolar planetary systems, including galaxies and Milky Way stars. These models are intended as inputs to high-fidelity simulations of direct observations of exoplanetary systems using telescopes equipped with high-contrast capability. They will help improve the realism of observation and instrument parameters that are required inputs to statistical observatory yield calculations, as well as guide development of post-processing algorithms for telescopes capable of directly imaging Earth-like planets.Comment: Accepted for publication in PAS

Lessons Learned from the Investigation of an Anomalous Termination of BETTII

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) mission launched from Palestine, Texas in June 2017. After an exciting launch and successful cruise, the BETTII gondola suffered an anomalous event at termination. BETTII separated from its parachute and free-fell 136,000 feet into the west Texas desert. This event was classified as a "close-call" and investigated as such. We present here the recovery effort required to find the payload and extract the payload from its impact site. We also present lessons learned from the event and results from the investigation, the design for the next BETTII gondola, and a path forward for return to flight

WFIRST CGI Integral Field Spectrograph Performance and Post-Processing in the OS6 Observing Scenario

The WFIRST coronagraph instrument (CGI) will have an integral field spectrograph (IFS) backend to disperse the entire field of view at once and obtain spatially-resolved, low-resolution spectra of the speckles and science scene. The IFS will be key to understanding the spectral nature of the speckles, obtain science spectra of planets and disks, and will be used for broadband wavefront control. In order to characterize, predict, and optimize the performance of the instrument, we present a detailed model of the IFS in the context of the new OS6 observing scenario. The simulation includes spatial, spectral, and temporal variations of the speckle field on the IFS detector plane, which allows us to explore several post-processing methods and assess what gains can be expected. The simulator includes the latest models of the detector behavior when operating in photon-counting mode

A Dispersive Backend Design for the 'Double-Fourier' Interferometer BETTII

BETTII (Balloon Experimental Twin Telescope for Infra-red Interferometry) is designed to provide high angular resolution spectroscopic data in the far-infrared (FIR) wavelengths. The most significant limitation for BETTII is its sensitivity; obtaining spectral signal-to-noise ratio greater than 5 in less than 10 minutes requires sources greater than 13 Janskys (Jy). One possible way to improve the signal-to-noise ratio (SNR) for future BETTII flights is by reducing the spectral bandwidth post beam-combination. This involves using a dispersive element to spread out a polychromatic point source PSF (Point Spread Function) on the detector array, such that each pixel corresponds to a small fraction of the bandwidth. This results in a broader envelope of the interferometric fringe pattern allowing more fringes to be detected, and thereby improving the spectral SNR. Here we present the analysis and optical design of the dispersive backend, discussing the tradeoffs and how it can be combined with the existing design

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): towards the first flight

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is a balloon-borne, far-infrared direct detection interferometer with a baseline of 8 m and two collectors of 50 cm. It is designed to study galactic clustered star formation by providing spatially-resolved spectroscopy of nearby star clusters. It is being assembled and tested at NASA Goddard Space Flight Center for a first flight in Fall 2016. We report on recent progress concerning the pointing control system and discuss the overall status of the project as it gets ready forits commissioning flight

Camilla: A Centaur reconnaissance and impact mission concept

Centaurs, minor planets with a semi-major axis between the orbits of Jupiter and Neptune (5–30 AU), are thought to be among the most diverse small bodies in the solar system. These important targets for future missions may have recently been Kuiper Belt Objects (KBOs), which are thought to be chemically and physically primitive remnants of the early solar system. While the Kuiper Belt spans distances of 30–50 AU, making direct observations difficult, Centaurs' proximity to the Earth and Sun make them more accessible targets for robotic missions. Thus, we outline a mission concept designed to reconnoiter 10199 Chariklo, the largest Centaur and smallest ringed body yet discovered. Named for a legendary Centaur tamer, the conceptual Camilla mission is designed to fit under the cost cap of the National Aeronautics and Space Administration (NASA) New Frontiers program, leveraging a conservative payload to support a foundational scientific investigation to these primitive bodies. Specifically, the single flyby encounter utilizes a combined high-resolution camera/VIS-IR mapping spectrometer, a sub-mm point spectrometer, and a UV mapping spectrometer. In addition, the mission concept utilizes a kinetic impactor, which would provide the first opportunity to sample the composition of potentially primitive subsurface material beyond Saturn, thus providing key insights into solar system origins. Such a flyby of the Chariklo system would provide a linchpin in the understanding of small body composition, evolution, and transport of materials in the solar system