VizieR Online Data Catalog: Composite quasar spectra from Gaia DR3 (Gaia Coll., 2023)

Composite spectra of quasars constructed from the Gaia BP/RP spectra of 42944 sources identified in the Gaia DR3 catalogue. These sources all have classprob_dsccombmod_quasar>0.01 in Gaia DR3 and a spectroscopically confirmed redshift in the Milliquas 7.2 quasar catalogue of Flesh et al. (2021yCat.7290....0F) - corresponding to a TYPE='Q' in Milliquas. A search radius of 1" is used to match the Gaia sources to their Milliquas counterparts, leading to a redshift coverage of 0.052<=z<=4.358. Redshifts from Milliquas are used to shift the observed BP/RP spectra into their restframes. Five composite spectra are also constructed from this sample using narrower redshift ranges: 0.052<=z<0.5 (2571 sources), 0.5<=z<1 (8810 sources), 1<=z<2 (20 755 sources), 2<=z<3 (9870 sources), and 3<=z<4 (929 sources). We have also constructed a "Gaia-only" composite spectrum based on a pure set of 111 563 BP/RP spectra selected from the Gaia classification and redshift predictions (see the appendix of the printed paper for details). The "Gaia-only" composite spectrum covers a predicted redshift range of 0.087<=z<= 6.128. All composite spectra are trimmed in order to remove wavelength regions whose signal-to-noise ratio is lower than one.

(7 data files).