Push-broom Mapping of Galaxies and Supernova Remnants with the SPRITE CubeSat

Abstract

Supernovae (SNe) enrich and energize the surrounding interstellar medium (ISM) and are a key mechanism in the galaxy feedback cycle. The heating of the ISM by supernova shocks, and its subsequent cooling is critical to future star formation. The cooling of the diffuse shock-heated ISM is dominated by ultraviolet (UV) emission lines. These cooling regions and interfaces have complex spatial structure on sub-parsec scales. Mapping this cooling process is essential to understanding the feedback cycle of galaxies, a major goal of the 2020 Astrophysics Decadal Survey. The Supernova remnants and Proxies for ReIonization Testbed Experiment (SPRITE) CubeSat Mission will house the first long-slit orbital spectrograph with sub-arcminute angular resolution covering far ultraviolet wavelengths (FUV; 1000 - 1750 angstroms) and access to the Lyman UV (lambda < 1216 angstroms). SPRITE aims to provide new insights into the stellar feedback that drives galaxy evolution by mapping key FUV emission lines at the interaction lines between supernova remnants (SNRs) and the ambient interstellar medium (ISM). SPRITE will also measure the ionizing escape from approximately 50 low-redshift (0.16 < z < 0.4) star-forming galaxies. Current models predict SPRITE capable of detecting strong O VI, O IV], and C IV emission lines with angular resolution from 10 - 20 arcseconds. The SPRITE SNR survey will use push-broom mapping of its long-slit on extended sources to produce the first large sample of sub-arcminute 3D data cubes of extended sources in the FUV. In this paper, we present simulated SPRITE observations of Large Magellanic Cloud (LMC) SNRs to demonstrate the efficacy of the SPRITE instrument ahead of launch and instrument commissioning. These models serve as critical planning tools and incorporate the final pre-flight predicted performance of the instrument and the early extended source data reduction pipeline.

Figures (11)

• Figure 1: FUSE and IUE spectra for N132D using separate pointings 1 and 2 respectively (see Section 4.4 for location in SNR). Prior to SPRITE, only HUT and SPEAR have been able to obtain spectra over the combined FUSE and IUE bandpass.
• Figure 2: Figure a) A rendering of SPRITE’s components inside of the chassis walls, including the spectrograph, telescope, electronics, and spacecraft avionics; b) An image of the assembled satellite showcasing the telescope; c) SPRITE personnel assembling the base-plate with the science instrument; d) An image of SPRITE electronics.
• Figure 3: Figure (Left) two-dimensional (raw) image from the SPRITE detector of a point-source lab calibration lamp spectra showing excited transitions of room air. The inset shows the three corresponding images through the SCC, tracking the distance between the slit regions. (Right) the extracted spectrum with lines labeled. These calibration images are used to establish the pre-flight imaging and spectral resolution, as well as scattered light background.
• Figure 4: SPRITE’s expected effective area in the case of using the flight grating is represented in solid blue. The effective area of the two most relevant missions for comparison, HUT and a single LiF+Al channel of FUSE, are shown in the dotted green lines and dashed purple respectively. The SPRITE effective area compares well with these previous larger and more expensive instruments.
• Figure 5: The following block flowchart highlights the main steps of creating 1D and 2D spectral models.