177 research outputs found
The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric precision and ghost analysis
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the
Thirty Meter Telescope (TMT) that will be used to sample the corrected adaptive
optics field by NFIRAOS with a near-infrared (0.8 - 2.4 m) imaging camera
and Integral Field Spectrograph (IFS). In order to understand the science case
specifications of the IRIS instrument, we use the IRIS data simulator to
characterize photometric precision and accuracy of the IRIS imager. We present
the results of investigation into the effects of potential ghosting in the IRIS
optical design. Each source in the IRIS imager field of view results in ghost
images on the detector from IRIS's wedge filters, entrance window, and
Atmospheric Dispersion Corrector (ADC) prism. We incorporated each of these
ghosts into the IRIS simulator by simulating an appropriate magnitude point
source at a specified pixel distance, and for the case of the extended ghosts
redistributing flux evenly over the area specified by IRIS's optical design. We
simulate the ghosting impact on the photometric capabilities, and found that
ghosts generally contribute negligible effects on the flux counts for point
sources except for extreme cases where ghosts coalign with a star of
m2 fainter than the ghost source. Lastly, we explore the photometric
precision and accuracy for single sources and crowded field photometry on the
IRIS imager.Comment: SPIE 2018, 14 pages, 14 figures, 4 tables, Proceedings of SPIE
10702-373, Ground-based and Airborne Instrumentation for Astronomy VII,
10702A7 (16 July 2018
The Bolocam Galactic Plane Survey: Survey Description and Data Reduction
We present the Bolocam Galactic Plane Survey (BGPS), a 1.1 mm continuum
survey at 33" effective resolution of 170 square degrees of the Galactic Plane
visible from the northern hemisphere. The survey is contiguous over the range
-10.5 < l < 90.5, |b| < 0.5 and encompasses 133 square degrees, including some
extended regions |b| < 1.5. In addition to the contiguous region, four targeted
regions in the outer Galaxy were observed: IC1396, a region towards the Perseus
Arm, W3/4/5, and Gem OB1. The BGPS has detected approximately 8400 clumps over
the entire area to a limiting non-uniform 1-sigma noise level in the range 11
to 53 mJy/beam in the inner Galaxy. The BGPS source catalog is presented in a
companion paper (Rosolowsky et al. 2010). This paper details the survey
observations and data reduction methods for the images. We discuss in detail
the determination of astrometric and flux density calibration uncertainties and
compare our results to the literature. Data processing algorithms that separate
astronomical signals from time-variable atmospheric fluctuations in the data
time-stream are presented. These algorithms reproduce the structure of the
astronomical sky over a limited range of angular scales and produce artifacts
in the vicinity of bright sources. Based on simulations, we find that extended
emission on scales larger than about 5.9' is nearly completely attenuated (>
90%) and the linear scale at which the attenuation reaches 50% is 3.8'.
Comparison with other millimeter-wave data sets implies a possible systematic
offset in flux calibration, for which no cause has been discovered. This
presentation serves as a companion and guide to the public data release through
NASA's Infrared Processing and Analysis Center (IPAC) Infrared Science Archive
(IRSA). New data releases will be provided through IPAC IRSA with any future
improvements in the reduction.Comment: Accepted for publication in Astrophysical Journal Supplemen
Structural and thermodynamic analysis of a three-component assembly forming <i>ortho</i>-iminophenylboronate esters
Structural studies of a three-component assembly - a host and two distinct guests - were carried out using a combination of 11B and 1H NMR. In aprotic solvent, the imino group that forms ortho to the boronic acid or boronate ester group can form a dative N-B bond. In protic solvent, a molecule of solvent inserts between the nitrogen and boron atoms, partially ionizing the solvent molecule. Additionally, 11B NMR was used in combination with a seventh-order polynomial to calculate five binding constants for each of the individual steps in protic solvent. Comparison of these binding constants was used to establish positive cooperativity in the binding of the two guests.</p
The symple choice algorythm for estimating of parametersof network protetion prioroties in analitical hierarchic process
Humans depend on services provided by ecosystems, and how services are affected by climate change is increasingly studied. Few studies, however, address changes likely to affect services from seminatural ecosystems. We analyzed ecosystem goods and services in natural and seminatural systems, specifically how they are expected to change as a result of projected climate change during the 21st century. We selected terrestrial and freshwater systems in northernmost Europe, where climate is anticipated to change more than the global average, and identified likely changes in ecosystem services and their societal consequences. We did this by assembling experts from ecology, social science, and cultural geography in workshops, and we also performed a literature review. Results show that most ecosystem services are affected by multiple factors, often acting in opposite directions. Out of 14 services considered, 8 are expected to increase or remain relatively unchanged in supply, and 6 are expected to decrease. Although we do not predict collapse or disappearance of any of the investigated services, the effects of climate change in conjunction with potential economical and societal changes may exceed the adaptive capacity of societies. This may result in societal reorganization and changes in ways that ecosystems are used. Significant uncertainties and knowledge gaps in the forecast make specific conclusions about societal responses to safeguard human well-being questionable. Adapting to changes in ecosystem services will therefore require consideration of uncertainties and complexities in both social and ecological responses. The scenarios presented here provide a framework for future studies exploring such issues
The Infrared Imaging Spectrograph (IRIS) for TMT: closed-loop adaptive optics while dithering
The InfraRed Imaging Spectrograph (IRIS) is the first-light client instrument
for the Narrow Field Infrared Adaptive Optics System (NFIRAOS) on the Thirty
Meter Telescope (TMT). IRIS includes three natural guide star (NGS)
On-Instrument Wavefront Sensors (OIWFS) to measure tip/tilt and focus errors in
the instrument focal plane. NFIRAOS also has an internal natural guide star
wavefront sensor, and IRIS and NFIRAOS must precisely coordinate the motions of
their wavefront sensor positioners to track the locations of NGSs while the
telescope is dithering (offsetting the telescope to cover more area), to avoid
a costly re-acquisition time penalty. First, we present an overview of the
sequencing strategy for all of the involved subsystems. We then predict the
motion of the telescope during dithers based on finite-element models provided
by TMT, and finally analyze latency and jitter issues affecting the propagation
of position demands from the telescope control system to individual motor
controllers.Comment: 21 pages, 19 figures, SPIE (2018) 10707-4
The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric characterization of anisoplanatic PSFs and testing of PSF-Reconstruction via AIROPA
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT) that will be used to sample the corrected adaptive optics field by the Narrow-Field Infrared Adaptive Optics System (NFIRAOS) with a near-infrared (0.8 - 2.4 µm) imaging camera and integral field spectrograph. To better understand IRIS science specifications we use the IRIS data simulator to characterize relative photometric precision and accuracy across the IRIS imaging camera 34”x34” field of view. Because the Point Spread Function (PSF) varies due to the effects of anisoplanatism, we use the Anisoplanatic and Instrumental Reconstruction of Off-axis PSFs for AO (AIROPA) software package to conduct photometric measurements on simulated frames using PSF-fitting as the PSF varies in single-source, binary, and crowded field use cases. We report photometric performance of the imaging camera as a function of the instrumental noise properties including dark current and read noise. Using the same methods, we conduct comparisons of photometric performance with reconstructed PSFs, in order to test the veracity of the current PSF-Reconstruction algorithms for IRIS/TMT
The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric characterization of anisoplanatic PSFs and testing of PSF-Reconstruction via AIROPA
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT) that will be used to sample the corrected adaptive optics field by the Narrow-Field Infrared Adaptive Optics System (NFIRAOS) with a near-infrared (0.8 - 2.4 µm) imaging camera and integral field spectrograph. To better understand IRIS science specifications we use the IRIS data simulator to characterize relative photometric precision and accuracy across the IRIS imaging camera 34”x34” field of view. Because the Point Spread Function (PSF) varies due to the effects of anisoplanatism, we use the Anisoplanatic and Instrumental Reconstruction of Off-axis PSFs for AO (AIROPA) software package to conduct photometric measurements on simulated frames using PSF-fitting as the PSF varies in single-source, binary, and crowded field use cases. We report photometric performance of the imaging camera as a function of the instrumental noise properties including dark current and read noise. Using the same methods, we conduct comparisons of photometric performance with reconstructed PSFs, in order to test the veracity of the current PSF-Reconstruction algorithms for IRIS/TMT
2012 Wild Blueberry Project Reports
The 2012 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
1. Do wild blueberries alleviate risk factors related to the Metabolic Syndrome?
2. Development of effective intervention measures to maintain and improve food safety for wild blueberries
3. Control tactics for blueberry pest insects, 2012
4. Development and implementation of a wild blueberry thrips IPM program, 2012
5. IPM
6. Biology of blueberry and pest insects, 2012
7. Biology of beneficial insects and blueberry pollination, 2012
8. Pesticide residues on lowbush blueberry, 2012
9. Maine wild blueberry –mummy berry research and extension
10. Efficacy of Apogee growth regulator for stimulating rhizome growth into bare spots in wild blueberry fields
11. Velpar by Matrix pre and post-emergence applications - demonstration plots
12. Wild blueberry Extension Education Program in 2012
INPUT SYSTEMS STUDY:
13. Systems approach to improving the sustainability of wild blueberry production, Year Three of a four-year study – experimental design
14. Food safety- Prevalence study of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp. on lowbush blueberries (Vaccinium angustifolium)
15. Abundance of insect pest species and natural enemies in lowbush blueberry fields maintained under different management practices
16. Input Systems Study: Systems approach to improving the sustainability of wild blueberry production, Year 3 of a four-year study, disease management results
17. Plant productivity, Year Three of a four-year study
18. Systems approach to improving the sustainability of wild blueberry production, Year Three of a four-year study, weed management results
19. Effects of organic and conventional management systems on the phosphorus solubility of lowbush blueberry barren soils
20. Systems approach to improving sustainability of wild blueberry production – soil health and chemistry measures
21. Evaluation of fungicides for control of mummy berry disease (ancillary study)
22. Systems approach to improving the sustainability of wild blueberry production – Ancillary land-leveling study, Year Two of a four-year study (ancillary study)
23. Pre-emergent combinations of herbicides for weed control in wild blueberry fields – 2012 results from the 2011 trial (ancillary study)
24. Pre-emergent combinations of herbicides for weed control in wild blueberry fields – 2012 trial (ancillary study)
25. Evaluation of herbicides for control of fineleaf sheep fescue for grass control in wild blueberries (ancillary study)
26. Pre-emergence application timing and rate of Alion and Sandea in combination with Velpar or Sinbar on weed control and injury to wild blueberry (ancillary study)
27. Compost and mulch effects on soil health and nutrient dynamics in wild blueberry (ancillary study
The Infrared Imaging Spectrograph (IRIS) for TMT: advancing the data reduction system
Infrared Imaging Spectrograph (IRIS) is the first light instrument for the
Thirty Meter Telescope (TMT) that consists of a near-infrared (0.84 to 2.4
micron) imager and integral field spectrograph (IFS) which operates at the
diffraction-limit utilizing the Narrow-Field Infrared Adaptive Optics System
(NFIRAOS). The imager will have a 34 arcsec x 34 arcsec field of view with 4
milliarcsecond (mas) pixels. The IFS consists of a lenslet array and slicer,
enabling four plate scales from 4 mas to 50 mas, multiple gratings and filters,
which in turn will operate hundreds of individual modes. IRIS, operating in
concert with NFIRAOS will pose many challenges for the data reduction system
(DRS). Here we present the updated design of the real-time and post-processing
DRS. The DRS will support two modes of operation of IRIS: (1) writing the raw
readouts sent from the detectors and performing the sampling on all of the
readouts for a given exposure to create a raw science frame; and (2) reduction
of data from the imager, lenslet array and slicer IFS. IRIS is planning to save
the raw readouts for a given exposure to enable sophisticated processing
capabilities to the end users, such as the ability to remove individual poor
seeing readouts to improve signal-to-noise, or from advanced knowledge of the
point spread function (PSF). The readout processor (ROP) is a key part of the
IRIS DRS design for writing and sampling of the raw readouts into a raw science
frame, which will be passed to the TMT data archive. We discuss the use of
sub-arrays on the imager detectors for saturation/persistence mitigation,
on-detector guide windows, and fast readout science cases (< 1 second).Comment: 14 pages, 5 figures, 6 tables, Proceeding 10707-112 of the SPIE
Astronomical Telescopes + Instrumentation 201
The Infrared Imaging Spectrograph (IRIS) for TMT: final design development of the data reduction system
IRIS (Infrared Imaging Spectrograph) is the near-infrared (0.84 to 2.4 micron) diffraction-limited imager and Integral Field Spectrograph (IFS) designed for the Thirty Meter Telescope (TMT) and the Narrow-Field Infrared Adaptive Optics System ( NFIRAOS ). The imager will have a 34 arcsec x 34 arcsec field of view with 4 milliarcseconds (mas) pixels. The IFS consists of a lenslet array and slicer, enabling four plate scales from 4 mas to 50 mas, with multiple gratings and filters. We will report the progress on the development of the IRIS Data Reduction System ( DRS ) in the final design phase. The IRIS DRS is being developed in Python with the software architecture based on the James Webb Space Telescope science calibration pipeline. We are developing a library of algorithms as individual Python classes that can be configured independently and bundled into pipelines. We will interface this with the observatory software to run online during observations and we will release the package publicly for scientists to develop custom analyses. It also includes a C library for readout processing to be used for both in real-time processing (e.g., up-the-ramp, MCDS) as well the ability for astronomers to use for offline reduction. Lastly, we will also discuss the development of the IRIS simulation packages that simulate raw spectra and image readout-data from the Hawaii-4RG detectors, which helps in developing reduction algorithms during this design phase
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