We present the analysis of the restframe optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z = 3.911. The spectroscopic data were taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between C III] λ1910 and [O III] λλ4959,5007. We have investigated the possible presence of multiple BALs by computing "balnicity" and absorption indexes (i.e., BI, BI0, and AI) for the transitions Si IV λ1400, C IV λ1549, Al III λ1860, and Mg II λ2800. No clear evidence for the presence of absorption features is found in addition to the already known, prominent BAL associated to C IV, which supports a high-ionization BAL classification for APM 08279+5255. We also studied the properties of the [O III], Hβ, and Mg II emission lines. We find that [O III] is intrinsically weak (F[OIII] FHβ 0.04), as it is typically found in luminous quasars with a strongly blueshifted C IV emission line (~2500 km s-1 for APM 08279+5255). We computed the single-epoch black hole mass based on Mg II and Hβ broad emission lines, finding MBH = (2 ÷ 3) × 1010μ-1 M·, with the magnification factor μ that can vary between 4 and 100 according to CO and restframe UV-to-mid-IR imaging respectively. Using a Mg II equivalent width (EW)-to-Eddington ratio relation, the EWMgII ∼ 27 Å measured for APM 08279+5255 translates into an Eddington ratio of ∼0.4, which is more consistent with μ = 4. This magnification factor also provides a value of MBH that is consistent with recent reverberation-mapping measurements derived from C IV and Si IV.

Saturni, F., Bischetti, M., Piconcelli, E., Bongiorno, A., Cicone, C., Feruglio, C., et al. (2018). Restframe UV-to-optical spectroscopy of APM 08279+5255: BAL classification and black hole mass estimates. ASTRONOMY & ASTROPHYSICS, 617, A118-A118 [10.1051/0004-6361/201832794].

Restframe UV-to-optical spectroscopy of APM 08279+5255: BAL classification and black hole mass estimates

Vignali, C.
Membro del Collaboration Group
2018

Abstract

We present the analysis of the restframe optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z = 3.911. The spectroscopic data were taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between C III] λ1910 and [O III] λλ4959,5007. We have investigated the possible presence of multiple BALs by computing "balnicity" and absorption indexes (i.e., BI, BI0, and AI) for the transitions Si IV λ1400, C IV λ1549, Al III λ1860, and Mg II λ2800. No clear evidence for the presence of absorption features is found in addition to the already known, prominent BAL associated to C IV, which supports a high-ionization BAL classification for APM 08279+5255. We also studied the properties of the [O III], Hβ, and Mg II emission lines. We find that [O III] is intrinsically weak (F[OIII] FHβ 0.04), as it is typically found in luminous quasars with a strongly blueshifted C IV emission line (~2500 km s-1 for APM 08279+5255). We computed the single-epoch black hole mass based on Mg II and Hβ broad emission lines, finding MBH = (2 ÷ 3) × 1010μ-1 M·, with the magnification factor μ that can vary between 4 and 100 according to CO and restframe UV-to-mid-IR imaging respectively. Using a Mg II equivalent width (EW)-to-Eddington ratio relation, the EWMgII ∼ 27 Å measured for APM 08279+5255 translates into an Eddington ratio of ∼0.4, which is more consistent with μ = 4. This magnification factor also provides a value of MBH that is consistent with recent reverberation-mapping measurements derived from C IV and Si IV.
2018
Saturni, F., Bischetti, M., Piconcelli, E., Bongiorno, A., Cicone, C., Feruglio, C., et al. (2018). Restframe UV-to-optical spectroscopy of APM 08279+5255: BAL classification and black hole mass estimates. ASTRONOMY & ASTROPHYSICS, 617, A118-A118 [10.1051/0004-6361/201832794].
Saturni, F.G.; Bischetti, M.; Piconcelli, E.; Bongiorno, A.; Cicone, C.; Feruglio, C.; Fiore, F.; Gallerani, S.; Giustini, M.; Piranomonte, S.; Vietri...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/673665
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