2.2 UV Observations

Simultaneous HST far-ultraviolet (FUV) spectra of PG1211+143 listed in Table 1 were obtained on 2015 April 12 and 14 over four observations (PID 13947, PI: Lee) using the Cosmic Origins Spectrograph (COS ; Osterman et al., 2011; Green et al., 2012). We used grating G140L to cover the 912-2000Å wavelength range. To fill in the gap from 1190-1270 Å between the two segments of the COS detector, we used grating G130M during the second visit. See §6 for a summary of the observational results, and Kriss et al. (2018) for details of the data reduction, calibration and analysis.

The earlier HST UV observations of PG1211+143 listed in Table 1 were taken on 1991 April 13 and 16 (PID 1026, PI: Burbidge) using the Faint Object Spectrograph (FOS ; Keyes et al., 1995). The FOS data were retrieved from the HST legacy archive, which include two exposures of 2.0ks made in the G130H (1150-1600Å), one exposure of 1.34ks in the G190H (1580-2330Å), and one exposure of 3.49ks in the G270H (2220-3300Å).