Table · dataset · 2025
eFEDS. X-ray sources SDSS spectroscopic obs.
Listed in IVOA Registry (Virtual Observatory)
We present one of the largest uniform optical spectroscopic surveys of X-ray selected sources to date observed as a pilot study for the Black Hole Mapper survey (BHM).
Description
The BHM program of the Sloan Digital Sky Survey (SDSS)-V is designed to provide optical spectra for hundreds of thousands of X-ray selected sources from the SRG/eROSITA all-sky survey, significantly improving our ability to classify and characterize the physical properties of large statistical populations of X-ray emitting objects.
Our sample consists of 13079 sources in the eROSITA eFEDS performance verification field, among which 12011 provide reliable redshifts from 0<z<5.8. The vast majority of these objects were detected as point-like sources (X-ray flux limit F_0.5_-2keV>6.5x10^15^erg/s/cm^2^) and observed, over about twenty years, with fiber-fed SDSS spectrographs. After including all available redshift information for the eFEDS sources from the dedicated SDSS-V plate programme and archival data, we visually inspected the SDSS optical spectra to check the reliability of these redshift measurements, as well as the performance of the SDSS pipeline.
Read the rest (2 more)
The visual inspection allowed both the recovery of reliable redshifts (for 99% of SNR> 2 spectra) and the assignment of classes to the sources, where we confirm that the vast majority of our sample consists of active galactic nuclei (AGN), with only ~3% of the eFEDS/SDSS sources being Galactic objects. We analyse the completeness and purity of the spectroscopic redshift catalogue, with the spectroscopic completeness rising from 48% (full sample) to 81% for a cleaner, brighter (rAB<21.38) sample defined considering high X-ray detection likelihood, reliable counterpart association, and optimal sky coverage.
We also showcase the diversity of the optical spectra of the X-ray-selected AGN, and provide high signal-to-noise ratio spectral stacks in various sub-samples of different redshift and optical broad-band colours. Our AGN sample contains optical spectra of (broad-line) quasars, narrow-line galaxies, and optically passive galaxies, showing considerable diversity in colours and levels of nuclear obscuration.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/698/A132 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2025A&A...698A.132A ui.adsabs.harvard.edu/abs/2025A%26A...698A.132A ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/a%2Ba/698/a132 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- X-Ray
- From keywords
- Astronomy & Astrophysics
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/698/a132 | 15 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:x-ray | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |