Weekly issue · Oct 5–11, 2026

Week 41, 2026

7 curated papers

01arXiv:2610.03877v1

Theme match 4/5

Internal Radiative Feedback Triggers Global Collapse and Direct-Collapse Black Hole Formation in Metal-free Atomic-Cooling Haloes

Masaki Kiyuna, Sunmyon Chon, Kazuyuki Omukai et al.

Cosmological radiation-hydrodynamic simulations suggest that Pop III stars can internally suppress H2 cooling after initial fragmentation, enabling warm-reservoir collapse and rapidly accreting supermassive-star candidates under modest external FUV fields rather than the conventionally required extreme irradiation.

What changes The proposed novelty is a causal sequence in which internal feedback triggers the conditions for global collapse instead of merely quenching star formation: initial Pop III stars dissociate H2, while atomic cooling permits the warm reservoir to collapse. The resulting stellar system is not claimed to be purely monolithic: numerous stars below ~10^3 Msun form, whereas the authors report ~90% of stellar mass accreted in this phase resides in a few protostars above ~10^4 Msun. The work further estimates a DCBH abundance of ~10^−3–10^−2 cMpc^−3 and presents this as plausibly sufficient for LRD/SMBH progenitors.

Figure notes (3)

Figure 2. Tests whether the late global-collapse episode changes stellar mass growth: it tracks total stellar mass, the eventual most-massive star, and that star’s share of total mass across the three J21 runs; open circles mark the defined onset of global-collapse-associated star formation.
Figure 9. Tests the proposed global-collapse scale dynamically. Density, temperature, and radial inflow-rate profiles evolve with time; local minima in the late inflow-rate profile define the collapse-region radii used by the authors.
Figure 12. Tests how final stellar mass is distributed among stars for J21=1, 10, and 100, and provides the captioned comparison curve from a J21=10^3 earlier run. It is a distributional comparison, not by itself evidence for a causal feedback mechanism.

02arXiv:2610.08964v1

Theme match 3/5

Can LISA See Inside the Little Red Dots?

Samuel Gómez Gómez, Xisco Jimenez Forteza, Carlos Palenzuela et al.

Modelled 10–30 solar-mass EMRIs could let LISA distinguish dense Little Red Dot interiors from vacuum, but detectability is confined largely to low-redshift, low-mass hosts and is dominated by uncertain inspiral rates and idealized gas dynamics.

What changes Rather than inferring LRD environments from spectra alone, the paper forecasts an EMRI-based discriminant among proposed interiors. For 14 JWST LRDs at z>3.9, none is detectable with a 10 M⊙ companion; for 31 objects at z<0.9, 30 would be detectable if their BHs are about 100 times below virial estimates. Population forecasts for a four-year mission are 0.08–0.8 detectable events for 10^5 M⊙ hosts with 10 M⊙ companions, rising to 1.5–15 for 30 M⊙ companions, conditional on ordinary-nucleus inspiral rates.

Figure notes (3)

Figure 1. Tests the physical separation of the assumed gas-density profiles at MBH=10^5 M⊙ across the radii traversed in the final four years before ISCO; it establishes why EMRI environmental effects may discriminate interiors.
Figure 2. Tests predicted four-year environmental dephasing against redshift for 10^4 and 10^5 M⊙ hosts with a 10 M⊙ companion, alongside SNR and perturbativity; it separates resolvable from gas-driven, non-perturbative cases.
Figure 4. Tests event-yield sensitivity to companion mass and LRD abundance under an assumed Γ=10^-6 yr^-1 per nucleus, showing where curves terminate at their SNR=10 horizons.

03arXiv:2610.08731v1

Theme match 3/5

Halo Mass Function Constraints on Early Galaxy and AGN Populations in the JWST Era

Elan Yogeswaren, Robert Schaefer

This framework treats JWST massive galaxies, AGN, and UV luminosity functions as host-halo supply tests. It finds that rare-halo abundance predictions depend strongly on high-redshift HMF calibration and assumed baryonic or black-hole mappings, precluding simple source-by-source consistency claims.

What changes Rather than interpreting any one bright source as decisive, the authors’ synthesis explicitly requires population consistency: inferred hosts must exist in adequate numbers. They use the same halo reservoir to connect three observables while separating cosmological abundance from astrophysical assignment of stellar mass, UV light, and black-hole activity. The ST–KST controlled comparison is presented as a sensitivity experiment, not a replacement cosmology or a binary falsification test.

JWST AGN
high-z

Figure notes (3)

Figure 3. Tests sensitivity of the differential HMF to the collapse/calibration prescription: KST rescales ST abundance at fixed redshift, with growing separation toward high redshift; its stated calibration range ends at z=10.
Figure 4. Tests whether observed stellar mass and cumulative number density can be supplied by halos under the absolute ε⋆=1 baryon-conversion ceiling, comparing ST with the lower KST reservoir and displaying observational uncertainty ranges near z≈7.5 and 9.1.
Figure 7. Tests AGN host availability by comparing cumulative halos above an assumed minimum host mass with high-redshift AGN abundance constraints. It is an upper bound before occupation fractions or duty cycles reduce the observable AGN abundance.

04arXiv:2610.03925v1

Theme match 3/5

The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback

Gabriel R. Hauschild-Roier, Thaisa Storchi-Bergmann, Rogério Riffel et al.

In SDSS fibre spectra of 1,541 type-1 and 688 type-2 QSOs at z=0.4–0.5, broad NLR components are more blueshifted in type 1s, consistent with orientation-dependent visibility of faster ionised outflowing gas, but energetics remain model-sensitive.

What changes Rather than relying only on a broad Gaussian, the work compares broad-component, W80, and W90 velocity prescriptions when estimating ionised mass outflow rates and powers. It frames the type-dependent broad-line kinematics statistically as an orientation effect—type 1 sightlines reaching gas nearer the nucleus—while noting that higher mean [O III] luminosity in type 2s could also indicate an evolutionary obscured phase. These are interpretations of population-level differences, not a demonstrated separation of orientation and evolution for individual QSOs.

Figure 1 from The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback

Figure 1 · Open paper

obscured AGN
QSO

Figure notes (3)

Figure 1. Defines the percentile velocities, W80/W90 widths, and centroid measured from a fitted double-Gaussian line profile; it tests the operational meaning of the kinematic diagnostics rather than an astrophysical difference.
Figure 5. Compares type-1 and type-2 distributions of mass outflow rate and power in the low-luminosity sample under three velocity estimators: broad component, W80, and W90.
Figure 10. Places broad-component-derived mass outflow rate and kinetic power against bolometric luminosity, with inclination-corrected type-2 broad velocities; it tests type-dependent scaling and comparison with literature/model efficiency lines.

05arXiv:2610.10117v1

Theme match 2/5

MUSE-ALMA Haloes XVI: a census of the condensed baryons in z~0.5 HI absorption-selected galaxies

T. O'Beirne, C. Péroux, M. Zwaan et al.

Across 79 H I absorber-selected galaxies at 0.2<z<1.2, the authors combine multiwavelength data to inventory stars and cold gas, finding broadly consistent indirect H I estimators at small impact parameter but environmentally driven scatter and mass-dependent gas fractions.

What changes The paper’s contribution is a joint, absorber-selected census connecting inferred atomic gas, CO-based molecular gas, stellar mass, and inner dynamical masses. Dynamical masses within 2R_e are derived from MUSE ionized-gas rotation and dispersion, with asymmetric-drift correction and HST Sérsic radii. The authors further report higher baryon fractions at high stellar surface density and discuss either feedback-related inner dark-matter-profile changes or aperture-dependent kinematic sampling. Figure 4 directly tests agreement between the two indirect H I estimators, while Figure 5 tests how atomic and molecular gas-to-stellar mass ratios vary with stellar mass.

Figure 1 from MUSE-ALMA Haloes XVI: a census of the condensed baryons in z~0.5 HI absorption-selected galaxies

Figure 1 · Open paper

QSO
spectroscopy
high-z

Figure notes (3)

Figure 1. Tests the inferred H I mass–stellar-mass relation against local xGASS, intermediate-redshift stacking, and low-redshift absorber-selected 21-cm measurements.
Figure 4. Tests consistency of optical-property and absorber-property H I scaling estimates; the authors identify a small-impact-parameter correlation but large environment-dependent scatter.
Figure 7. Tests inferred inner dark-matter fraction versus redshift against galaxy surveys and TNG50 analogues, while displaying the aperture mismatch among samples.

06arXiv:2610.10522v1

Theme match 2/5

Widespread steep X-ray spectra of luminous $z\simeq5.85-7.6$ quasars and their implications for future X-ray surveys

A. Tortosa, L. Zappacosta, E. Piconcelli et al.

Across 28 luminous quasars at z=5.85–7.56, X-ray continua are systematically steep, yet show no significant dependence on black-hole growth indicators. The inferred spectral shapes could modestly to severely reduce high-redshift survey count rates.

What changes The principal advance is a more growth-rate-diverse, comparably luminous EoR QSO sample with consistently updated mass/growth characterization, including ten JWST Balmer-line-based mass estimates. The result shifts the interpretation from steep spectra being peculiar to the most efficiently grown HYPERION black holes to their being widespread among these luminous z≳6 QSOs. Under the explicitly limiting assumption that this mean Γ≈2.4 applies to the broader EoR AGN population, soft-band count-rate reductions are ≲20% at fixed intrinsic L2–10 keV, but can exceed factors of ten for Γ~3–3.5 or observed hard-band measurements.

$Figure 2 from Widespread steep X-ray spectra of luminous $z\simeq5.85-7.6$ quasars and their implications for future X-ray surveys$ Figure 2 · Open paper

QSO
spectroscopy
high-z

Figure notes (3)

Figure 2. Tests whether photon index and cutoff energy vary with the adopted black-hole growth indicator, and visually compares the detected-QSO mean with typical low-z unobscured-AGN Γ and Ec ranges.
Figure 4. Directly compares the Γ probability distributions of this z≳6 sample and z~2–4 QSOs; the uncertainty-propagated KS exercise supports a statistically persistent difference between the distributions.
Figure 9. Tests the instrumental count-rate bias caused by steep Γ or low Ec for NewAthena/WFI at z=5 and z=10, separately in soft and hard observed bands.

07arXiv:2610.06680v1

Theme match 2/5

Unveiling the Origins of the Molecular Gas Reservoirs in Recently Quenched Massive Galaxies

E. Savitch, D. Narayanan, D. J. Setton et al.

In Simba, apparently molecular-gas-rich recently quenched galaxies can reflect dust-hidden star formation, a low CO–H2 conversion factor, or temporary quiescence. The model favors no single explanation; rejuvenation is high-redshift-weighted and comparatively uncommon.

What changes Rather than treating molecular gas in quenched galaxies as one anomaly, the paper tests three competing, potentially coexisting interpretations in one simulation framework. It further connects the selection problem to observables: UBV-selected systems peak at z=2 in the modeled sample, and dust-rich selected galaxies can have IR SFRs that track their true SFR while UV SFRs underpredict it. The authors also find that their sSFR-based low-SFR selection is more H2-rich than an SFMS-offset selection, a choice that directly affects the inferred prevalence of gas-rich quiescence.

Figure 3 from Unveiling the Origins of the Molecular Gas Reservoirs in Recently Quenched Massive Galaxies

Figure 3 · Open paper

obscured AGN
high-z

Figure notes (3)

Figure 3. Tests the redshift dependence of rejuvenation by separating the number of identified events from the fraction of transitioning/quenched galaxies that later rejuvenate; the latter declines toward z=0 in the model.
Figure 6. Tests whether αCO covaries with star-formation state for all massive z=0 and 1 galaxies. A bootstrapped linear fit shows lower-than-Milky-Way αCO for quenched, transitioning, and weakly star-forming systems.
Figure 15. Tests the observational fidelity of Simba’s UBV-selected analogue by stacking its z=0.5 SEDs against roughly 1,300 SQuIGGℒE galaxies at z=0.5–0.9; the caption reports redder observed SEDs and a stronger Balmer break in SQuIGGℒE.