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تسجيل مستخدم جديدThe Science Vision for the Stratospheric Observatory for Infrared Astronomy (SOFIA)
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An updated Science Vision for the SOFIA project is presented, including an overview of the characteristics and capabilities of the observatory and first generation instruments. A primary focus is placed on four science themes: The Formation of Stars and Planets, The Interstellar Medium of the Milky Way, Galaxies and the Galactic Center and Planetary Science.
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The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory consisting of a specially modified Boeing 747SP with a 2.7-m telescope, flying at altitudes as high as 13.7 km (45,000 ft). Designed to observe at wavelengths fro
m 0.3 micron to 1.6 mm, SOFIA operates above 99.8 % of the water vapor that obscures much of the infrared and submillimeter. SOFIA has seven science instruments under development, including an occultation photometer, near-, mid-, and far-infrared cameras, infrared spectrometers, and heterodyne receivers. SOFIA, a joint project between NASA and the German Aerospace Center DLR, began initial science flights in 2010 December, and has conducted 30 science flights in the subsequent year. During this early science period three instruments have flown: the mid-infrared camera FORCAST, the heterodyne spectrometer GREAT, and the occultation photometer HIPO. This article provides an overview of the observatory and its early performance.
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servable from airborne or space-based platforms, no first-generation instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA) is presently designed with polarimetric capabilities. We study several options for upgrading the High-resolution Airborne Wideband Camera (HAWC) to a sensitive FIR polarimeter. HAWC is a 12 x 32 pixel bolometer camera designed to cover the 53 - 215 micron spectral range in 4 colors, all at diffraction-limited resolution (5 - 21 arcsec). Upgrade options include: (1) an external set of optics which modulates the polarization state of the incoming radiation before entering the cryostat window; (2) internal polarizing optics; and (3) a replacement of the current detector array with two state-of-the-art superconducting bolometer arrays, an upgrade of the HAWC camera as well as polarimeter. We discuss a range of science studies which will be possible with these upgrades including magnetic fields in star-forming regions and galaxies and the wavelength-dependence of polarization.
SPHEREx is a proposed NASA MIDEX mission selected for Phase A study. SPHEREx would carry out the first all-sky spectral survey in the near infrared. At the end of its two-year mission, SPHEREx would obtain 0.75-to-5$mu$m spectra of every 6.2 arcsec p
ixel on the sky, with spectral resolution R>35 and a 5-$sigma$ sensitivity AB$>$19 per spectral/spatial resolution element. More details concerning SPHEREx are available at http://spherex.caltech.edu. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light. Though these three themes are undoubtedly compelling, they are far from exhausting the scientific output of SPHEREx. Indeed, SPHEREx would create a unique all-sky spectral database including spectra of very large numbers of astronomical and solar system targets, including both extended and diffuse sources. These spectra would enable a wide variety of investigations, and the SPHEREx team is dedicated to making the data available to the community to enable these investigations, which we refer to as Legacy Science. To that end, we have sponsored two workshops for the general scientific community to identify the most interesting Legacy Science themes and to ensure that the SPHEREx data products are responsive to their needs. In February of 2016, some 50 scientists from all fields met in Pasadena to develop these themes and to understand their implications for the SPHEREx mission. The 2016 workshop highlighted many synergies between SPHEREx and other contemporaneous astronomical missions, facilities, and databases. Consequently, in January 2018 we convened a second workshop at the Center for Astrophysics in Cambridge to focus specifically on these synergies. This white paper reports on the results of the 2018 SPHEREx workshop.
Building on the experience of the high-resolution community with the suite of VLT high-resolution spectrographs, which has been tremendously successful, we outline here the (science) case for a high-fidelity, high-resolution spectrograph with wide wa
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For astronomers to make a significant contribution to the reduction of climate change-inducing greenhouse gas emissions, we first must quantify our sources of emissions and review the most effective approaches for reducing them. Here we estimate that
Australian astronomers total greenhouse gas emissions from their regular work activities are $gtrsim$25 ktCO$_2$-e/yr (equivalent kilotonnes of carbon dioxide per year). This can be broken into $sim$15 ktCO$_2$-e/yr from supercomputer usage, $sim$4.2 ktCO$_2$-e/yr from flights (where individuals flight emissions correlate with seniority), $>$3.3 ktCO$_2$-e/yr from the operation of observatories, and 2.6$pm$0.4 ktCO$_2$-e/yr from powering office buildings. Split across faculty scientists, postdoctoral researchers, and PhD students, this averages to $gtrsim$37 tCO$_2$-e/yr per astronomer, over 40% more than what the average Australian non-dependant emits in total, equivalent to $sim$5$times$ the global average. To combat these environmentally unsustainable practices, we suggest astronomers should strongly preference use of supercomputers, observatories, and office spaces that are predominantly powered by renewable energy sources. Where facilities that we currently use do not meet this requirement, their funders should be lobbied to invest in renewables, such as solar or wind farms. Air travel should also be reduced wherever possible, replaced primarily by video conferencing, which should also promote inclusivity.
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