Observer-Frame Time Accounting in the Formation History of the z = 7.54 Quasar ULAS J1342+0928

Version 1.0 — Preprint (submitted manuscript) This record hosts the Version 1.0 preprint (submitted manuscript) of: “Observer-Frame Time Accounting in the Formation History of the z = 7.54 Quasar ULAS J1342+0928” This case-study builds on the EAoU framework introduced in Hossain (2025, 2026). High-redshift quasars at z ≳ 7 are often interpreted as forming within a very limited cosmic time budget when evaluated using the standard comoving proper time in the FLRW–ΛCDM framework. ULAS J1342+0928 (z = 7.54), hosting an ∼8 × 10⁸ M⊙ supermassive black hole in a chemically evolved environment, provides a concrete case where this apparent “time compression” becomes especially prominent. This work examines the formation history of ULAS J1342+0928 using an observer-accumulated time accountingderived directly from the standard cosmological redshift relation: dT_obs = (1 + z) dt and the corresponding accumulated duration: T_eff(z) = ∫ da / (a² H(a)). No modification of the FLRW metric or ΛCDM expansion history is introduced; the approach is a frame-consistent reinterpretation of accumulated durations inferred from high-redshift observations. The manuscript provides: conservative object-level lower bounds on nuclear maturation timescales (star formation, enrichment, mixing, and fueling readiness), supermassive black hole growth times under Eddington-limited accretion across a range of seed masses, Eddington ratios, and duty cycles, and a direct comparison between conventional FLRW proper-time budgets and observer-accumulated durations relevant for high-redshift evolutionary histories. Appendix A includes a step-by-step derivation and numerical framework for computing both FLRW cosmic time and observer-accumulated duration.