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Abstract We report the discovery of an accreting supermassive black hole atz= 8.679. This galaxy, denoted here as CEERS_1019, was previously discovered as a Lyα-break galaxy by Hubble with a Lyαredshift from Keck. As part of the Cosmic Evolution Early Release Science (CEERS) survey, we have observed this source with JWST/NIRSpec, MIRI, NIRCam, and NIRCam/WFSS and uncovered a plethora of emission lines. The Hβline is best fit by a narrow plus a broad component, where the latter is measured at 2.5σwith an FWHM ∼1200 km s−1. We conclude this originates in the broadline region of an active galactic nucleus (AGN). This is supported by the presence of weak high-ionization lines (N V, N IV], and C III]), as well as a spatial point-source component. The implied mass of the black hole (BH) is log (MBH/M⊙) = 6.95 ± 0.37, and we estimate that it is accreting at 1.2 ± 0.5 times the Eddington limit. The 1–8μm photometric spectral energy distribution shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/M⊙∼9.5) and highly star-forming (star formation rate, or SFR ∼ 30 M⊙yr−1; log sSFR ∼ − 7.9 yr−1). The line ratios show that the gas is metal-poor (Z/Z⊙∼ 0.1), dense (ne∼ 103cm−3), and highly ionized (logU∼ − 2.1). We use this present highest-redshift AGN discovery to place constraints on BH seeding models and find that a combination of either super-Eddington accretion from stellar seeds or Eddington accretion from very massive BH seeds is required to form this object.
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Calibration of Solid State Nuclear Track Detectors for rare event searches
Abstract The calibration of the CR39®and Makrofol®Nuclear Track Detectors of the MoEDAL experiment at the CERN-LHC was performed by exposing stacks of detector foils to heavy ion beams with energies ranging from 340 MeV/nucleon to 150 GeV/nucleon. After chemical etching, the base areas and lengths of etch-pit cones were measured using automatic and manual optical microscopes. The response of the detectors as measured by the ratio of the track-etching rate over the bulk-etching rate, was determined over a range extending from their threshold at Z/β∼ 7 and ∼ 50 for CR39 and Makrofol, respectively, up to Z/β∼ 92.
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- Award ID(s):
- 2309505
- PAR ID:
- 10580216
- Publisher / Repository:
- JINST
- Date Published:
- Journal Name:
- Journal of Instrumentation
- Volume:
- 20
- Issue:
- 03
- ISSN:
- 1748-0221
- Page Range / eLocation ID:
- P03014
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1088/1748-0221/20/03/P03014
