Radio astronomy archives present particular challenges due to the complexity of the data processing. New radio telescopes such as the Jansky-VLA and ALMA also have much larger data volumes than the previous generation of instruments, requiring large amounts of storage and processing. Here we describe the approach taken by NRAO towards making the data products of the VLA and ALMA available to our users. This includes traditional approaches of pipelining and imaging, and also on-demand server side processing, visualization and analysis. We discuss how the size of the image products is related to that of the visibility data, and how this places variable demands on the data flow from the telescope and its data center as configurations are changed throughout the year. Finally, we look ahead to the next generation of radio telescopes such as the SKA and ngVLA.
The Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership of Europe, North America and East Asia in cooperation with the Republic of Chile, is the largest astronomical project in existence. While ALMA’s capabilities are ramping up, Early Science observations have started. The ALMA Archive is at the center of the operations of the telescope array and is designed to manage the 200 TB of data that will be taken each year, once the observatory is in full operations. We briefly describe design principles. The second part of this paper focuses on how astronomy is likely to evolve as the amount and complexity of data taken grows. We argue that in the future observatories will compete for astronomers to work with their data, that observatories will have to reorient themselves to from providing good data only to providing an excellent end-to-end user-experience with all its implications, that science-grade data-reduction pipelines will become an integral part of the design of a new observatory or instrument and that all this evolution will have a deep impact on how astronomers will do science. We show how ALMA’s design principles are in line with this paradigm.
We present an overview of the calibration and properties of data from the IRAC instrument aboard the Spitzer Space
Telescope taken after the depletion of cryogen. The cryogen depleted on 15 May 2009, and shortly afterward a two-month-
long calibration and characterization campaign was conducted. The array temperature and bias setpoints were
revised on 19 September 2009 to take advantage of lower than expected power dissipation by the instrument and to
improve sensitivity. The final operating temperature of the arrays is 28.7 K, the applied bias across each detector is 500
mV and the equilibrium temperature of the instrument chamber is 27.55 K. The final sensitivities are essentially the
same as the cryogenic mission with the 3.6 μm array being slightly less sensitive (10%) and the 4.5 μm array within 5%
of the cryogenic sensitivity. The current absolute photometric uncertainties are 4% at 3.6 and 4.5 μm, and better than
milli-mag photometry is achievable for long-stare photometric observations. With continued analysis, we expect the
absolute calibration to improve to the cryogenic value of 3%. Warm IRAC operations fully support all science that was
conducted in the cryogenic mission and all currently planned warm science projects (including Exploration Science
programs). We expect that IRAC will continue to make ground-breaking discoveries in star formation, the nature of the
early universe, and in our understanding of the properties of exoplanets.
We present an analysis of the stability of the Infrared Array Camera (IRAC) on board the Spitzer Space Telescope over
the first 4.5 years of in-flight operations. IRAC consists of two InSb and two Si:As 256x256 imaging arrays with
passbands centered on 3.6, 4.5. 5.8 and 8.0 microns. Variations in photometric stability, read noise, dark offsets, pixel
responsivity and number of hot and noisy pixels for each detector array are trended with time. To within our
measurement uncertainty, the performance of the IRAC arrays has not changed with time. The most significant variation
is that number of hot pixels in the 8 micron array has increased linearly with time at a rate of 60 pixels per year. We
expect that the 3.6 and 4.5 micron arrays should remain stable during the post-cryogenic phase of the Spitzer mission.
We will briefly discuss some science that is enabled by the excellent stability of IRAC.
We report on observations of two quasar host galaxies made with the Lick Observatory adaptive optic system using a laser guide star tuned to the wavelength of the sodium D lines. A brief outline of the system is given, and a description of its performance when obtaining science data. We discuss techniques for obtaining calibration of the point spread function and the analysis steps required to obtain useful scientific results. We present H-band images of quasar host galaxies made with the system. Estimates of the host galaxy
magnitudes and central black hole masses were made from these data.
These are the first observations of quasar host galaxies with a sodium laser guide star.
We describe the astronomical observation template (AOT) for the Infrared Array Camera (IRAC) on the Spitzer Space Telescope (formerly SIRTF, hereafter Spitzer). Commissioning of the AOTs was carried out in the first three months of the Spitzer mission. Strategies for observing fixed and moving targets are described, along with the performance of the AOT in flight. We also outline the operation of the IRAC data reduction pipeline at the Spitzer Science Center (SSC) and describe residual effects in the data due to electronic and optical anomalies in the instrument.
The Infrared Array Camera (IRAC) on Spitzer Space Telescope includes four Raytheon Vision Systems focal plane arrays, two with InSb detectors, and two with Si:As detectors. A brief comparison of pre- flight laboratory results vs. in-flight performance is given, including quantum efficiency and noise, as well as a discussion of irregular effects, such as residual image performance, "first frame effect", "banding", "column pull-down" and multiplexer bleed. Anomalies not encountered in pre-flight testing, as well as post-flight laboratory tests on these anomalies at the University of Rochester and at NASA Ames using sister parts to the flight arrays, are emphasized.
The Infrared Array Camera (IRAC) is one of three focal plane instruments on board the Spitzer Space Telescope. IRAC is a four-channel camera that obtains simultaneous broad-band images at 3.6, 4.5, 5.8, and 8.0 μm in two nearly adjacent fields of view. We summarize here the in-flight scientific, technical, and operational performance of IRAC.
The Infrared Array Camera (IRAC) is one of three focal plane instruments in the Space Infrared Telescope Facility (SIRTF). IRAC is a four-channel camera that obtains simultaneous images at 3.6, 4.5, 5.8, and 8 microns. Two adjacent 5.12x5.12 arcmin fields of view in the SIRTF focal plane are viewed by the four channels in pairs (3.6 and 5.8 microns; 4.5 and 8 microns). All four detector arrays in the camera are 256x256 pixels in size, with the two shorter wavelength channels using InSb and the two longer wavelength channels using Si:As IBC detectors. We describe here the results of the instrument functional and calibration tests completed at Ball Aerospace during the integration with the cryogenic telescope assembly, and provide updated estimates of the in-flight sensitivity and performance of IRAC in SIRTF.