End-to-end ground calibration and in-flight performance of the FIREBall-2 instrument

TL;DR

This paper details the calibration, in-flight performance, and sensitivity predictions of the FIREBall-2 balloon-borne spectrograph, demonstrating its capability to detect specific galactic emission lines but with limitations in resolving the circumgalactic medium.

Contribution

It presents the first multi-object acquisition from space with FIREBall-2 and provides calibration and performance analysis based on flight data.

Findings

Successful multi-object acquisition from space

Predicted detection of HI Lyα in galaxies at z~0.67

Challenges in resolving the circumgalactic medium

Abstract

The payload of the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2), the second generation of the FIREBall instrument (PI: C. Martin, Caltech), has been calibrated and launched from the NASA Columbia Scientific Balloon Facility (CSBF) in Fort Sumner, NM. FIREBall-2 was launched for the first time on the 22nd September 2018, and the payload performed the very first multi-object acquisition from space using a multi-object slit spectrograph (MOS). This performance-oriented paper presents the calibration and last ground adjustments of FIREBall-2, the in-flight performance assessed based on the flight data, and the predicted instrument's ultimate sensitivity. This analysis predicts that future flights of FIREBall-2 should be able to detect the HI Ly\alpha resonance line in galaxies at z~0.67, but will find it challenging to spatially resolve the circumgalactic medium (CGM).