The Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR) is one of four large mission concepts currently undergoing community study for consideration by the 2020 Astronomy and Astrophysics Decadal Survey. LUVOIR is being designed to pursue an ambitious program of exoplanetary discovery and characterization, cosmic origins astrophysics, and planetary science. The LUVOIR study team is investigating two large telescope apertures (9- and 15-meter primary mirror diameters) and a host of science instruments to carry out the primary mission goals. Many of the exoplanet, cosmic origins, and planetary science goals of LUVOIR require high-throughput, imaging spectroscopy at ultraviolet (100 – 400 nm) wavelengths. The LUVOIR Ultraviolet Multi-Object Spectrograph, LUMOS, is being designed to support all of the UV science requirements of LUVOIR, from exoplanet host star characterization to tomography of circumgalactic halos to water plumes on outer solar system satellites. LUMOS offers point source and multi-object spectroscopy across the UV bandpass, with multiple resolution modes to support different science goals. The instrument will provide low (R = 8,000 – 18,000) and medium (R = 30,000 – 65,000) resolution modes across the far-ultraviolet (FUV: 100 – 200 nm) and nearultraviolet (NUV: 200 – 400 nm) windows, and a very low resolution mode (R = 500) for spectroscopic investigations of extremely faint objects in the FUV. Imaging spectroscopy will be accomplished over a 3 × 1.6 arcminute field-of-view by employing holographically-ruled diffraction gratings to control optical aberrations, microshutter arrays (MSA) built on the heritage of the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST), advanced optical coatings for high-throughput in the FUV, and next generation large-format photon-counting detectors. The spectroscopic capabilities of LUMOS are augmented by an FUV imaging channel (100 – 200nm, 13 milliarcsecond angular resolution, 2 × 2 arcminute field-of-view) that will employ a complement of narrow- and medium-band filters. The instrument definition, design, and development are being carried out by an instrument study team led by the University of Colorado, Goddard Space Flight Center, and the LUVOIR Science and Technology Definition Team. LUMOS has recently completed a preliminary design in Goddard’s Instrument Design Laboratory and is being incorporated into the working LUVOIR mission concept. In this proceeding, we describe the instrument requirements for LUMOS, the instrument design, and technology development recommendations to support the hardware required for LUMOS. We present an overview of LUMOS’ observing modes and estimated performance curves for effective area, spectral resolution, and imaging performance. Example “LUMOS 100-hour Highlights” observing programs are presented to demonstrate the potential power of LUVOIR’s ultraviolet spectroscopic capabilities.
Dark matter in a universe dominated by a cosmological constant seeds the formation of structure and is the scaffolding
for galaxy formation. The nature of dark matter remains one of the fundamental unsolved problems in astrophysics and
physics even though it represents 85% of the mass in the universe, and nearly one quarter of its total mass-energy
budget. The mass function of dark matter "substructure" on sub-galactic scales may be enormously sensitive to the mass
and properties of the dark matter particle. On astrophysical scales, especially at cosmological distances, dark matter
substructure may only be detected through its gravitational influence on light from distant varying sources. Specifically,
these are largely active galactic nuclei (AGN), which are accreting super-massive black holes in the centers of galaxies,
some of the most extreme objects ever found. With enough measurements of the flux from AGN at different
wavelengths, and their variability over time, the detailed structure around AGN, and even the mass of the super-massive
black hole can be measured. The Observatory for Multi-Epoch Gravitational Lens Astrophysics (OMEGA) is a mission
concept for a 1.5-m near-UV through near-IR space observatory that will be dedicated to frequent imaging and
spectroscopic monitoring of ~100 multiply-imaged active galactic nuclei over the whole sky. Using wavelength-tailored
dichroics with extremely high transmittance, efficient imaging in six channels will be done simultaneously during each
visit to each target. The separate spectroscopic mode, engaged through a flip-in mirror, uses an image slicer
spectrograph. After a period of many visits to all targets, the resulting multidimensional movies can then be analyzed to
a) measure the mass function of dark matter substructure; b) measure precise masses of the accreting black holes as well
as the structure of their accretion disks and their environments over several decades of physical scale; and c) measure a
combination of Hubble's local expansion constant and cosmological distances to unprecedented precision. We present
the novel OMEGA instrumentation suite, and how its integrated design is ideal for opening the time domain of known
cosmologically-distant variable sources, to achieve the stated scientific goals.
The Universe appears to be expanding at an accelerating rate, driven by a mechanism called Dark Energy. The nature of Dark Energy is largely unknown and needs to be derived from observation of its effects. JEDI (Joint Efficient Dark-energy Investigation) is a candidate implementation of the NASA-DOE Joint Dark Energy Mission (JDEM). It will probe the effects of Dark Energy in three independent ways: (1) using Type Ia supernovae as cosmological standard candles over a range of distances, (2) using baryon acoustic oscillations as a cosmological standard ruler over a range of cosmic epochs, and (3) mapping the weak gravitational lensing distortion by foreground galaxies of the images of background galaxies at different distances. JEDI provides crucial systematic error checks by simultaneously applying these three independent observational methods to derive the Dark Energy parameters. The concordance of the results from these methods will not only provide an unprecedented understanding of Dark Energy, but also indicate the reliability of such an understanding. JEDI will unravel the nature of Dark Energy by obtaining observations only possible from a vantage point in space, coupled with a unique instrument design and observational strategy. Using a 2 meter-class space telescope with simultaneous wide-field imaging (~ 1 deg2, 0.8 to 4.2 μm in five bands) and multi-slit spectroscopy (minimum wavelength coverage 1 to 2 μm), JEDI will efficiently execute the surveys needed to solve the mystery of Dark Energy.