Infrared Dust Emission in Starburst Galaxies: Self-Consistent Modeling From the UV to Far Infrared.

In the first part of this thesis, the ultraviolet extinction from dust in the Large Magellanic Cloud is re-analyzed. Differences in the extinction properties between different lines of sight, as well as between the LMC, SMC, and Milky Way are discussed in the context of their implications for the constitution and size distributions of the dust grains. The UV extinction curves derived in this work, along with those from other studies, have been used to constrain dust models used as inputs to dust heating models. Next, the DIRTY model, a Monte Carlo radiative transfer code from the ultraviolet to the far IR, is extended to self-consistently include dust heating and emission, fully accounting for the effects of the transient heating of small grains. The code is completely general; the density structure of the dust, heating sources, and their geometric configurations can be specified arbitrarily. The dust scattering, absorbing, and emitting properties are calculated from realistic dust models derived by fitting observed extinction curves. Dust self-absorption is also accounted for by treating photons emitted by the dust as an additional heating source and adopting an iterative radiative transfer scheme. The dependence of the UV-FIR SED, dust temperatures, and dust masses predicted by DIRTY on variations of the input parameters is examined. Finally, the DIRTY model is applied directly to a sample of nearby starburst galaxies. The UV to far IR SEDs of the galaxies are well reproduced using DIRTY, and quantitative information including star formation rates, dust masses, and dust temperatures are derived. The ability to accurately reproduce the full SED of starburst galaxies is discussed in the context of modeling galaxies at high redshift. The model developed in this thesis is well suited to simulate galaxies at different evolutionary stages and hence has promise for investigating the star formation history of the universe. However, it must be emphasized that its range of applicability is not limited to galaxies. It should prove a useful tool in future investigations of a wide range of astrophysical systems in which dust plays an important role

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit