Multi-epoch Detection of an Ultra-fast Inflow in ESP 39607: Evidence for an Accretion Cascade
Abstract
We present simultaneous XRISM, XMM-Newton, and NuSTAR observations of ESP 39607, a Seyfert 2 galaxy at z = 0.201. XRISM/Resolve reveals two absorption features near 4.7 and 4.9 keV in the observed frame, consistent with redshifted Fe XXV He-α/Fe XXVI Ly-α absorption from gas inflowing at vin ≃ 0.16c. The high velocity identifies the absorber as an ultra-fast inflow (UFI), which is detected at ∼ 3-3.7σ across different methods and continuum models. Photoionization modeling yields log ξ/erg s−1 cm ≃ 3.7-$3.8$ and a column density log NH,abs/cm−2 ≃ 23.2-$23.8$, the latter depending on the assumed metallicity. The inflow velocity and line properties are consistent with those reported from two earlier NuSTAR epochs, indicating that similar inflowing material was present over a baseline of at least 2.2 yr in the source rest frame. Across all three epochs, the combined detection significance of the UFI is 5.3σ. Given the dynamical timescale of a few days at the inferred radius, R ≃ 49-77 Rg, the multi-year evidence favors a scenario in which the inflow is continuously replenished, forming an accretion "cascade", rather than a single long-lived cloud. With an estimated mass inflow rate of Ṁin ≃ 0.3-1.4 M⊙ yr−1, depending on metallicity, and a ratio Ṁin/Ṁacc ≃ 0.2-$1.0$, the inflow could supply a substantial fraction of the accretion needed to power the central active galactic nucleus.
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BibTeX
@misc{peca2026multiepoch,
title = {{Multi-epoch Detection of an Ultra-fast Inflow in ESP 39607: Evidence for an Accretion Cascade}},
author = {Alessandro Peca and Michael J. Koss and Roberto Serafinelli and C. Megan Urry and Claudio Ricci and Keigo Fukumura and Massimo Gaspari and Elias Kammoun and Alessia Tortosa and Giulia Cerini and Peter G. Boorman and Richard Mushotzky and Quirino D'Amato},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03019},
eprint = {2609.03019},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03019},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Multi-epoch Detection of an Ultra-fast Inflow in ESP 39607: Evidence for an Accretion Cascade
AU - Alessandro Peca
AU - Michael J. Koss
AU - Roberto Serafinelli
AU - C. Megan Urry
AU - Claudio Ricci
AU - Keigo Fukumura
AU - Massimo Gaspari
AU - Elias Kammoun
AU - Alessia Tortosa
AU - Giulia Cerini
AU - Peter G. Boorman
AU - Richard Mushotzky
AU - Quirino D'Amato
PY - 2026
DA - 2026/09/05
PB - arXiv
DO - 10.48550/arxiv.2609.03019
UR - https://arxiv.org/abs/2609.03019
AB - We present simultaneous XRISM, XMM-Newton, and NuSTAR observations of ESP 39607, a Seyfert 2 galaxy at z = 0.201. XRISM/Resolve reveals two absorption features near 4.7 and 4.9 keV in the observed frame, consistent with redshifted Fe XXV He-α/Fe XXVI Ly-α absorption from gas inflowing at v_in ≃ 0.16c. The high velocity identifies the absorber as an ultra-fast inflow (UFI), which is detected at ∼ 3-3.7σ across different methods and continuum models. Photoionization modeling yields log ξ/erg s^−1 cm ≃ 3.7-$3.8$ and a column density log N_H,abs/cm^−2 ≃ 23.2-$23.8$, the latter depending on the assumed metallicity. The inflow velocity and line properties are consistent with those reported from two earlier NuSTAR epochs, indicating that similar inflowing material was present over a baseline of at least 2.2 yr in the source rest frame. Across all three epochs, the combined detection significance of the UFI is 5.3σ. Given the dynamical timescale of a few days at the inferred radius, R ≃ 49-77 R_g, the multi-year evidence favors a scenario in which the inflow is continuously replenished, forming an accretion "cascade", rather than a single long-lived cloud. With an estimated mass inflow rate of Ṁ_in ≃ 0.3-1.4 M_⊙ yr^−1, depending on metallicity, and a ratio Ṁ_in/Ṁ_acc ≃ 0.2-$1.0$, the inflow could supply a substantial fraction of the accretion needed to power the central active galactic nucleus.
ER -