VizieR Online Data Catalog: Follow-up spectroscopy of SDSS changing-look QSOs (Macleod+, 2019)
Abstract
We use imaging data from the SDSS and Pan-STARRS 1 (PS1) to select strongly variable quasars for spectroscopic follow-up. See Section 2 and 3.1.1.
Relatively bright (g<20.5) and highly variable (|Δg|>1.3mag) changing-look quasar (CLQ) candidates were observed on the nights of 2016 February 6-8 and May 30, 31 using the 4.2m William Herschel Telescope (WHT) in La Palma. Observations were performed using the Intermediate dispersion Spectrograph and Imaging System (ISIS). The setup gives a spectral resolution of R~1500 at 5200Å in the blue and R~1000 at 7200Å in the red for a slit width of 1.0" and nominal total coverage of ~3100 to 10600Å (but effectively further limited by the atmosphere). Observations of a fainter set of targets were made with the Blue Channel Spectrograph on the 6.5m MMT situated on Mount Hopkins, Arizona. Observations were carried out over several dates in 2016 to 2018 (see Table 2). The central wavelength setting ranged from 5835 to 6335Å. To observe most of our targets in the South Galactic Cap (SGC), and most of the relatively high-redshift targets, we used the Magellan Clay 6.5m telescope with the Low Dispersion Survey Spectrograph 3 (LDSS3)-C spectrograph. Observations were carried out over the nights 2016 July 26-29 (range 4250-10000Å). We also obtained second-epoch spectra of two quasars with Double Spectrograph (DBSP) on the Hale 200" Telescope at Palomar Observatory on UT 2017 May 30, and second-epoch spectra of an additional six quasars using the same instrument on UT 2017 June 26. (2 data files).- Publication:
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VizieR Online Data Catalog
- Pub Date:
- August 2020
- DOI:
- 10.26093/cds/vizier.18740008
- Bibcode:
- 2020yCat..18740008M
- Keywords:
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- QSOs;
- Spectra: optical;
- Redshifts;
- Photometry: SDSS