The low-mass dwarf host galaxy of nonrepeating FRB 20230708A

We present Very Large Telescope/X-Shooter spectroscopy for the host galaxies of 12 fast radio bursts (FRBs) detected by the Australian SKA Pathfinder (ASKAP), observed through the ESO Large Programme \"FURBY\", which imposes strict selection criteria on the included FRBs and their host galaxies to produce a homogeneous and well-defined sample. We describe the data reduction and analysis of these spectra and report their redshifts, line-emission fluxes, and derived host properties. From the present sample, this paper focuses on the faint host of FRB (mR = 22.53 +/- 0.02) identified at low redshift (z = 0.1050). This indicates an intrinsically very low-luminosity galaxy (L ~ 108 L_Sun), making it the lowest-luminosity non-repeating FRB host to date by a factor of ~3, and slightly dimmer than the lowest-luminosity host for repeating FRBs. Our SED fitting analysis reveals a low stellar mass (M* ~ 108 MSun), low star formation rate (SFR ~ 0.04 MSun/yr), and very low metallicity (12 + log(..., , # Data from: The low-mass dwarf host galaxy of nonrepeating FRB 20230708A

Dataset DOI: [10.5061/dryad.d2547d8hh](https://doi.org/10.5061/dryad.d2547d8hh)

## Description of the data and file structure

These data were obtained with the X-Shooter spectrograph on the Very Large Telescope owned and operated by the European Southern Observatory. These are spectra of the galaxies hosting fast radio bursts.

### Files and variables

Each file is an ASCII+binary FITS file which contains a 1D spectrum as observed in a single arm of the VLT/X-Shooter spectrograph. Files are labelled by FRB TNS name, galaxy coordinates, and X-Shooter arm (U = UVB, V = VIS, N = NIR).

The first extension of the FITS file contains the ASCII header, which provides the metadata of the observation and the software used to process the data.

The second extension of the FITS file is a binary table with these columns:

* wave -- wavelengths of the spectrum (Angstroms) 
* wave_grid_mid -- wavelengths of the spectrum at t..., ,