A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of z > 6.5 Quasars Using JWST
Studies of rest-frame optical emission in quasars at z > 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations...
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Veröffentlicht in: | Astrophysical journal. Letters 2023-07, Vol.951 (1), p.L5 |
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Sprache: | eng |
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Zusammenfassung: | Studies of rest-frame optical emission in quasars at
z
> 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at
z
> 6.5 using the JWST/NIRCam Wide Field Slitless Spectroscopy as a part of the “A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)” program. Our JWST spectra cover the quasars’ emission between rest frame ∼4100 and 5100 Å. The profiles of these quasars’ broad H
β
emission lines span a full width at half maximum from 3000 to 6000 km s
−1
. The H
β
-based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their Mg
ii
-based BH masses. The new measurements based on the more reliable H
β
tracer thus confirm the existence of a billion solar-mass BHs in the reionization epoch. In the observed [O
iii
]
λ
λ
4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components (≤ 1200 km s
−1
), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [O
iii
] emission, thought to trace galactic-scale outflows, with median velocities of −610 and −1430 km s
−1
relative to the [C
ii
] 158
μ
m line. All eight quasars show strong optical Fe
ii
emission and follow the eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties. |
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ISSN: | 2041-8205 2041-8213 |
DOI: | 10.3847/2041-8213/acc9c8 |