VizieR Online Data Catalog: Gaia GraL. VI. Quadruply imaged lensed QSOs (Stern+, 2021)

Spectroscopic follow-up for the Gaia Gravitational Lenses group (GraL) program began in 2018 May and has used the Keck I Telescope atop Maunakea, Hawaii, the 200" Hale Telescope at Palomar Observatory, California, the 3.6m New Technology Telescope (NTT) at La Silla, Chile, and the Gemini-South telescope at Cerro Pachon, Chile. 20 GraL observing nights with at least one GraL spectrum were obtained between 2018 May 13 and 2020 Jun 20.

The primary instrument for GraL spectroscopic follow-up has been the Low Resolution Imaging Spectrometer (LRIS) on the Keck I telescope, used for 13 of the 20 GraL nights. Our LRIS instrument configuration covers the full optical window at moderate resolving power, R~1000 for the 1.5" slit and R~1500 for the 1.0" slit (for objects filling the slit).

Several lens candidates were observed with the Palomar Double Spectrograph (DBSP) in 2018 August. None of the confirmed quadruply imaged quasars were observed with Palomar, though two doubly imaged quasars in Krone-Martins+ (2019arXiv191208977K ; Paper V) were confirmed on these runs, and several of the GraL lens candidates were invalidated at Palomar. This instrument configuration covers the full optical window at moderate resolving power, R~1250.

We used the ESO Faint Object Spectrograph and Camera (v.2; EFOSC2) on the NTT on the nights of UT 2019 April 7-9 (PI: Ducourant; Program ID 0103.A-0077). See Section 3.3.

Seven candidates were observed in queue-mode using the Gemini-South Multi-Object Spectrograph (GMOS) in integral field unit (IFU) mode (PI: Teixeira; Program ID GS-2019A-Q-104). We used the lowest-resolution grating which covered the 7000-8200Å spectral range with a resolving power R~2000.

(2 data files).