Rest-Frame Optical Spectroscopy of Ten z $\sim$ 2 Weak Emission-Line Quasars
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arXiv
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| Autori principali: | , , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866909241420283904 |
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| author | Chen, Ying Luo, Bin Brandt, W. N. Zuo, Wenwen Dix, Cooper Ha, Trung Matthews, Brandon Paul, Jeremiah D. Plotkin, Richard M. Shemmer, Ohad |
| author_facet | Chen, Ying Luo, Bin Brandt, W. N. Zuo, Wenwen Dix, Cooper Ha, Trung Matthews, Brandon Paul, Jeremiah D. Plotkin, Richard M. Shemmer, Ohad |
| contents | We present near-infrared spectroscopy of ten weak emission-line quasars (WLQs) at redshifts of $z\sim2$, obtained with the Palomar 200-inch Hale Telescope. WLQs are an exceptional population of type 1 quasars that exhibit weak or no broad emission lines in the ultraviolet (e.g., the C IV $λ1549$ line), and they display remarkable X-ray properties. We derive H$β$-based single-epoch virial black-hole masses (median value $\rm 1.7 \times 10^{9} M_{\odot}$) and Eddington ratios (median value $0.5)$ for our sources. We confirm the previous finding that WLQ H$β$ lines, as a major low-ionization line, are not significantly weak compared to typical quasars. The most prominent feature of the WLQ optical spectra is the universally weak/absent [O III] $λ5007$ emission. They also display stronger optical Fe II emission than typical quasars. Our results favor the super-Eddington accretion scenario for WLQs, where the weak lines are a result of a soft ionizing continuum; the geometrically thick inner accretion disk and/or its associated outflow is responsible for obscuring the nuclear high-energy radiation and producing the soft ionizing continuum. We also report candidate extreme [O III] outflows (blueshifts of $\approx 500$ and $\rm 4900 km s^{-1}$) in one object. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_03422 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Rest-Frame Optical Spectroscopy of Ten z $\sim$ 2 Weak Emission-Line Quasars Chen, Ying Luo, Bin Brandt, W. N. Zuo, Wenwen Dix, Cooper Ha, Trung Matthews, Brandon Paul, Jeremiah D. Plotkin, Richard M. Shemmer, Ohad Astrophysics of Galaxies We present near-infrared spectroscopy of ten weak emission-line quasars (WLQs) at redshifts of $z\sim2$, obtained with the Palomar 200-inch Hale Telescope. WLQs are an exceptional population of type 1 quasars that exhibit weak or no broad emission lines in the ultraviolet (e.g., the C IV $λ1549$ line), and they display remarkable X-ray properties. We derive H$β$-based single-epoch virial black-hole masses (median value $\rm 1.7 \times 10^{9} M_{\odot}$) and Eddington ratios (median value $0.5)$ for our sources. We confirm the previous finding that WLQ H$β$ lines, as a major low-ionization line, are not significantly weak compared to typical quasars. The most prominent feature of the WLQ optical spectra is the universally weak/absent [O III] $λ5007$ emission. They also display stronger optical Fe II emission than typical quasars. Our results favor the super-Eddington accretion scenario for WLQs, where the weak lines are a result of a soft ionizing continuum; the geometrically thick inner accretion disk and/or its associated outflow is responsible for obscuring the nuclear high-energy radiation and producing the soft ionizing continuum. We also report candidate extreme [O III] outflows (blueshifts of $\approx 500$ and $\rm 4900 km s^{-1}$) in one object. |
| title | Rest-Frame Optical Spectroscopy of Ten z $\sim$ 2 Weak Emission-Line Quasars |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2407.03422 |