Pioneering Ultraviolet Integral-Field Spectrograph Technologies for Deep Mapping of Galaxy Halos

IONIZED GAS IN THE CIRCUMGALACTIC MEDIUM (CGM) TRACES THE INTERACTION BETWEEN GALAXIES AND THEIR SURROUNDING MEDIUM FUELS FUTURE STAR FORMATION IN GALAXIES AND MAY HOLD A SIGNIFICANT PROPORTION OF UNDETECTED BARYONS IN THE PRESENT UNIVERSE. HOWEVER BECAUSE IT IS EXTREMELY DIFFUSE AND FAINT IT HAS BEEN DIFFICULT TO MAP IN EMISSION AND HAS PREVIOUSLY BEEN EXPLORED MAINLY IN SINGLE ABSORPTION SIGHT LINES. INSTRUMENTS SUCH AS THE FAINT INTERGALACTIC MEDIUM REDSHIFTED BALLOON (FIREBALL-2) AND CIRCUMGALACTIC H-ALPHA SPECTROGRAPH.(CHAS) WILL SURVEY THE COMPLEX DYNAMICS OF THE CGM AND HAVE DEVELOPED TECHNOLOGY FOR OBSERVING THIS FAINT EMISSION. WE PROPOSE DIFFUSAT A CUBESAT CARRYING AN INTEGRAL FIELD SPECTROGRAPH WHICH WILL MAP THE CGM OF NEARBY GALAXIES IN UV DEEPER THAN EVER BEFORE. DIFFUSAT'S WIDE FIELD OF VIEW HIGH GRASP AND MODERATE RESOLUTION WILL ALLOW IT TO OBTAIN THREE-DIMENSIONAL SPATIAL AND KINEMATIC INFORMATION OVER THE ENTIRE CGM OF NEARBY GALAXIES GIVING US AN UNPRECEDENTED VIEW OF ITS LARGE-SCALE STRUCTURE AND THE CYCLING OF GAS BETWEEN GALAXIES AND HALOS. THE DESIGN OF THIS INSTRUMENT WILL INVOLVE DEVELOPMENT OF KEY TECHNOLOGIES SUCH AS LENSLET.ARRAYS IN THE UV AND IN SPACE AND CCD COATINGS ENHANCING EFFICIENCY IN THE UV FOR USE IN FUTURE NASA MISSIONS.