Hypervelocity supernova survivor search spectra

Spectra release for the Gaia hypervelocity-runaway search

This data release contains reduced spectra obtained for the systematic Gaia hypervelocity-runaway follow-up program described by El-Badry et al. (2023, 2026). Publicly available survey spectra (e.g. from LAMOST, Gaia XP, etc) are not duplicated here. 

If you have question, contact me at kelbadry@caltech.edu. 
 
Directory layout

- `confirmed_runaways/`: spectra of confirmed or literature runaway objects discussed in the paper.
- `contaminants/`: spectra of candidate-list false positives obtained during follow-up.

Instruments and file formats

SOAR/Goodman spectra

Files are in `contaminants/soar_goodman/` and `confirmed_runaways/soar_goodman/`. These are ASCII text files. The first column is air wavelength in Angstrom and the second column is flux in arbitrary units.

Keck/LRIS spectra

Files are in `contaminants/lris/` and `confirmed_runaways/lris/`. They are ASCII spectra with FITS-like header comments beginning with `#`, followed by spectral columns. Some sources have separate blue- and red-side files. Wavelengths are air. 

For  J1949+0745, the `coadd/` subdirectory contains inverse-variance coadds of the three blue-side exposures, the three red-side exposures, and a convenience merged blue+red spectrum. The coadd columns are wavelength in Angstrom, flux, flux uncertainty, and number of contributing exposures. The merged blue+red spectrum uses the blue-side coadd below 5500 Angstrom and the red-side coadd at and above 5500 Angstrom.

Palomar/DBSP spectra

Files are in `contaminants/dbsp/`. Most are PypeIt `spec1d` FITS products. Science spectra are stored in binary-table extensions with columns including `OPT_WAVE` (vacuum), `OPT_FLAM`, `OPT_FLAM_SIG`, `OPT_FLAM_IVAR`, and related extraction diagnostics.  

Magellan/MagE spectra

Confirmed runaways are in `confirmed_runaways/mage/`; MagE contaminant spectra are in `contaminants/mage/`. The coadded FITS spectra contain a `SPECTRUM` binary-table extension with columns including `wave` (vacuum), `flux`, `ivar`, and `mask`. 

Gemini/GMOS spectra

Files are in `confirmed_runaways/gmos/`. `Gaia_5290_updated.dat` is the coadded, normalized rest-frame spectrum used for the J0812-5943 figure. The directory also includes reduced PypeIt `spec1d` products for J1251-5059. Wavelengths are vacuum. 

Keck/ESI spectra

Files are in `confirmed_runaways/esi/` and `contaminants/esi/`. They are MAKEE-reduced ESI FITS products. `Flux-*` files contain flux spectra and `Err-*` files contain the corresponding error spectra. The primary HDU is a 2D image with echelle order and pixel axes; wavelength (vacuum)/order information is stored in the FITS headers. For J0546+0836, the three matching `Flux-*` and `Err-*` exposures are included.

VLT/X-shooter spectra

Merged text spectra are in `confirmed_runaways/xshooter/merged_text/`. These files generally have three columns: wavelength in Angstrom (air), flux, and flux uncertainty.

Final reduced 1D arm products are in `confirmed_runaways/xshooter/reduced_1d_fits/`. For the flux-calibrated `FLUX_MERGE1D` products, the primary HDU contains flux, extension 1 contains the uncertainty, and extension 2 contains the quality array. The wavelength solution is encoded in the FITS header/WCS. For Gaia_3507, the available final products are unfluxed `SCI_SLIT_MERGE1D` files.

HST/COS spectra

Files are in `confirmed_runaways/hst_cos/`. FITS files are COS `x1dsum` or `cspec` products with spectral arrays such as `WAVELENGTH`, `FLUX`, and `ERROR`. Text files named `*_rest_frame.dat` are local rest-frame spectra with columns wavelength, flux, and uncertainty.

The first of these spectra was analyzed by Werner et al. 2024 (https://ui.adsabs.harvard.edu/abs/2024A%26A...689L...6W/abstract). The other spectra have not been analyzed. If you would like to work on these data, you are welcome to, but please keep me in the loop.