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Register a new userCalibrating the James Webb Space Telescope filters as star formation rate indicators
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We have calibrated the 6.5 m James Webb Space Telescope (JWST) mid-infrared filters as star formation rate indicators, using JWST photometry synthesized from $Spitzer$ spectra of 49 low redshift galaxies, which cover a wider luminosity range than most previous studies. We use Balmer decrement corrected $rm{Halpha}$ luminosity and synthesized mid-infrared photometry to empirically calibrate the $Spitzer$, WISE and JWST filters as star formation rate indicators. Our $Spitzer$ and WISE calibrations are in good agreement with recent calibrations from the literature. While mid-infrared luminosity may be directly proportional to star formation rate for high luminosity galaxies, we find a power-law relationship between mid-infrared luminosity and star formation rate for low luminosity galaxies ($L_{rm Halpha} leq 10^{43}~{rm erg~s^{-1}}$). We find that for galaxies with a $rm{Halpha}$ luminosity of $rm{10^{40}}~erg~s^{-1}$ (corresponding to a star formation rate of $sim 0.055~{rm M_odot~yr^{-1}}$), the corresponding JWST mid-infrared $ u L_{ u}$ luminosity is between $rm{10^{40.50}}$ and $rm{10^{41.00}}~erg~s^{-1}$. Power-law fits of JWST luminosity as a function of $rm{Halpha}$ luminosity have indices between 1.17 and 1.32. We find that the scatter in the JWST filter calibrations decreases with increasing wavelength from 0.39 to 0.20 dex, although F1000W is an exception where the scatter is just 0.24 dex.
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The James Webb Space Telescope (JWST), as the largest space-based astronomical observatory with near- and mid-infrared instrumentation, will elucidate many mysterious aspects of comets. We summarize four cometary science themes especially suited for this telescope and its instrumentation: the drivers of cometary activity, comet nucleus heterogeneity, water ice in comae and on surfaces, and activity in faint comets and main-belt asteroids. With JWST, we can expect the most distant detections of gas, especially CO2, in what we now consider to be only moderately bright comets. For nearby comets, coma dust properties can be studied with their driving gases, measured simultaneously with the same instrument or contemporaneously with another. Studies of water ice and gas in the distant Solar System will help us test our understanding of cometary interiors and coma evolution. The question of cometary activity in main-belt comets will be further explored with the possibility of a direct detection of coma gas. We explore the technical approaches to these science cases and provide simple tools for estimating comet dust and gas brightness. Finally, we consider the effects of the observatorys non-sidereal tracking limits, and provide a list of potential comet targets during the first 5 years of the mission.
The James Webb Space Telescope will enable a wealth of new scientific investigations in the near- and mid-infrared, with sensitivity and spatial/spectral resolution greatly surpassing its predecessors. In this paper, we focus upon Solar System science facilitated by JWST, discussing the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. We also present numerous example observing scenarios for a wide variety of Solar System targets to illustrate the potential of JWST science to the Solar System community. This paper updates and supersedes the Solar System white paper published by the JWST Project in 2010 (Lunine et al., 2010). It is based both on that paper and on a workshop held at the annual meeting of the Division for Planetary Sciences in Reno, NV in 2012.
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