Data for "A binary system in the S cluster close to the supermassive black hole Sagittarius A*"

Data related to the Nature Communications publication "A binary system in the S cluster close to the supermassive black hole Sagittarius A*" (Peißker et al. 2025).

The list of data contains science-ready observations from 2019 that were downloaded from the Keck Observatory Archive (KOA). This data can be smoothed with a 3-pixel Gaussian or smooth subtracted with a 6-pixel Gaussian (PSF sized) and smoothed again with a 3-pixel Gaussian. Both methods show D9 at the expected position.

The H and K band continuum images are extracted from a SINFONI data cube. In addition, a Br\gamma line map of the data cube that covers the entire observation epoch in 2019 is added. This file shows three sources: D9, D23, and X8 (see Peißker et al. 2024a for an overview). Some remnants of other G objects can be found.

For the SED fit, we included the input file (d9_input.txt) that can be used with the SED fitter. The fitter is described here https://sedfitter.readthedocs.io/en/stable/index.html and can be downloaded from GitHub (https://github.com/astrofrog/sedfitter).

The fitter used about 10000 individual models that were compared with the input flux (see also Robitaille et al. 2017). The related output file is uploaded here (parameters_d9.txt).

All spectra are extracted using an aperture of radius 2. Please note that the variable background, weather conditions, and data quality may impact the spectrum. A local background subtraction has been applied.

The data for Figure 3 in the manuscript, including the RV model, is uploaded. In addition, the file with the epoch and related Doppler-shifted wavelength is added to this database. 

The spectrum between 2005 and 2019 was observed with SINFONI and shows the Br\gamma emission of D9. In 2022, the Galactic center was observed with ERIS. Again, both spectra show the related Br\gamma emission of D9. Please note a calibration inconsistency for the ERIS observation on 13-06-2022 visible by the line emission of the Brr\gamma bar (Peißker et al. 2020c). This is fixed by an adjusted CRVAL1 value of 1.93432 µm.

In the related manuscript, we present a periodic pattern of the D9 binary system using the data between 2013 and 2019. This data was used for the fitting tool Exo-Stricker. All other data is used to verify our findings. Hence, the data between 2005-2012 and 2022 is not fitted but acts as an independent verification of the findings.

We recommend using QFitsView to inspect the data (https://www.mpe.mpg.de/~ott/QFitsView/).