Table 1.
Spectroscopic epochs and X-ray and radio properties.
Epoch | MJD (date) | Instrument | X-ray (§) | Radio (†) | Brγ EW [Å] (‡) | BrγFWHM [km s−1] | Ks (AB mag) |
---|---|---|---|---|---|---|---|
E–18A | 58 263.207 (2018-05-25) | GTC/EMIR | High | Quiet | 10.8 ± 0.7 | 590 ± 30 | 14.53 ± 0.12 |
E–18B | 58 305.005 (2018-07-06) | GTC/EMIR | High | Quiet | 9.7 ± 0.6 | 630 ± 30 | – |
E–18C | 58 315.951 (2018-07-16) | GTC/EMIR | High | Quiet | 6.5 ± 0.9 | 620 ± 60 | – |
E–18D | 58 354.025 (2018-08-24) | GTC/EMIR | High | Quiet | 3.7 ± 1.2 | 600 ± 150 | – |
E–19A | 58 626.323 (2019-05-23) | VLT/X-shooter | Low | Loud | 66.9 ± 0.1 | 2090 ± 20 | 14.18 ± 0.03 (a) |
E–19B | 58 633.308 (2019-05-30) | VLT/X-shooter | Low | Loud | 33.4 ± 0.1 | 1058 ± 14 | ∼14.9 (b) |
E–19C | 58 640.284 (2019-06-06) | VLT/X-shooter | Low | Loud | 59.6 ± 0.1 | 1740 ± 30 | ∼13.6 (b) |
E–19D | 58 659.199 (2019-06-25) | VLT/X-shooter | Low | Loud | 27.5 ± 0.1 | 813 ± 11 | ∼13.9 (b) |
E–21A | 59 446.019 (2021-08-20) | GTC/EMIR | Flare | Quiet | 7.8 ± 0.5 | 660 ± 40 | 15.33 ± 0.03 |
E–21B | 59 451.095 (2021-08-25) | GTC/EMIR | Flare | Quiet | 6.1 ± 0.4 | 486 ± 13 | 15.10 ± 0.05 |
59 451.989 (2021-08-25) | |||||||
59 453.075 (2021-08-27) | |||||||
E–21C | 59 476.904 (2021-09-19) | GTC/EMIR | Low | Quiet | 8.4 ± 0.7 | 810 ± 90 | 14.82 ± 0.04 |
E–22A | 59 828.021 (2022-09-06) | GTC/EMIR | Low | Quiet | < 0.17 | – | – |
59 830.052 (2022-09-08) | |||||||
E–22B | 59 859.906 (2022-10-07) | GTC/EMIR | Low | Quiet | < 0.17 | – | 15.8 ± 0.2 |
E–22C | 59 891.803 (2022-11-08) | GTC/EMIR | Low | Quiet | < 0.17 | – | 15.7 ± 0.2 |
59 894.810 (2022-11-11) | |||||||
59 895.811 (2022-11-12) | |||||||
E–23A | 60 076.375 (2023-05-12) | VLT/X-shooter | Low | Loud | 138.3 ± 0.1 | 641 ± 7 | ∼12.7 (b) |
E–23B | 60 082.374 (2023-05-18) | VLT/X-shooter | Low | Loud | 99.1 ± 0.1 | 626 ± 6 | ∼12.2 (b) |
E–23C | 60 094.285 (2023-05-30) | VLT/X-shooter | Low | Loud | 142.7 ± 0.1 | 674 ± 6 | ∼12.3 (b) |
E–23D | 60 161.195 (2023-08-05) | VLT/X-shooter | Low | Loud | 37.31 ± 0.05 | 620 ± 7 | ∼12.9 (b) |
Notes.
The label “high” indicates X-ray fluxes ≥0.2 × 10−8 erg cm−2 s−1, whereas “low” corresponds to < 0.1 × 10−8 erg cm−2 s−1. Observations taken during X-ray flares (“flare”) have associated fluxes in the range of ∼0.1 − 0.2 × 10−8 erg cm−2 s−1 (Fig. 1).
Radio-quiet periods exhibit fluxes of ∼1–5 mJy, whereas radio-loud epochs range from ∼10 to 2000 mJy (Fig. 1).
From the value Ks = 12.33 ± 0.03 (Vega) obtained by Vishal et al. (2019) four days before E-19A. We use mAB − mVega = 1.85 (Blanton & Roweis 2007).
Derived from the flux calibrated spectra and comparison with E-19A (see Sect. 2.2).
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