Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms

Brian D. Metzger; Claudio Ricci; Daniele Rogantini; Daniel Kasen; Ehud Behar; Erin Kara; Erwan Quintin; Fatima Zaidouni; Frits Paerels; Giovanni Miniutti

REVIEW

Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms

High Energy Astrophysical Phenomena · Submitted 28 Aug 2026

Pith's verdict: New data and a clever wind model for QPEs, but the key assumption that X-rays are kinetically powered rather than accretion-powered is not independently tested, so the energetics are plausible but not yet locked down.

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CitationBrian D. Metzger, Claudio Ricci, Daniele Rogantini, Daniel Kasen, Ehud Behar, Erin Kara, Erwan Quintin, Fatima Zaidouni, Frits Paerels, Giovanni Miniutti, Itai Linial, Joheen Chakraborty, Lorena Hernandez-Garcia, Margherita Giustini, Olivia Aspegren, Paula Sanchez-Saez, Peter Kosec, Riccardo Arcodia, Sudip Bhattacharyya, Wenbin Lu. "Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms." arXiv:2608.28507 (2026). https://pith.science/paper/VNIWXJK2

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The new XMM-Newton observations of Ansky are impressive — deepest look at any QPE, clearly showing time-evolving P Cygni profiles from Fe XIX–XXIV. The detection alone is novel, and the ionization-response explanation for the profile evolution is a real step forward over the earlier velocity-change interpretation. The data analysis is careful (pile-up checks, multi-instrument consistency), and the time-dependent wind model is a sensible way to tie the light curve to the line evolution with relatively few parameters.

The soft spot is the one flagged by the stress test: Equation 2, which assumes the X-ray luminosity is entirely wind-powered with constant radiative efficiency. That assumption is what converts the observed light curve into mass-loss rate and kinetic energy. If ϵ_X varies, or if the X-rays come from accretion rather than the wind, the inferred Ṁ_w, M_ej (~10^{-3} M⊙), and E_K (~10^{49} erg) all lose support. The model’s mild circularity — using L_X(t) both to drive the wind density and to compute the ionization — doesn’t help. The fit statistics (C-stat/dof ~1.7–2.0) aren’t great either, and the coarse grid (two velocities, three columns) leaves real room for degeneracy.

That said, the paper is open about these limitations. The model is called a “toy model,” the grid is acknowledged as coarse, and the assumptions are stated. The multiwavelength predictions (radio afterglow, infrared echo) are clearly testable, which is exactly what a good model should do.

This paper is for the QPE community — it provides the most quantitative constraints yet on eruption energetics and mass loss, and it gives EMRI modelers something concrete to compare against. It deserves a serious referee. The main thing I’d ask in review is a sensitivity analysis on the constant-efficiency assumption: how would the results change if ϵ_X is allowed to vary? Even a simple bounding exercise would help.

Referee report

Significance

If the central assumption that the X-ray emission is kinetically powered (Eq. 2) is correct, this work would provide the first quantitative demonstration that QPEs are driven by relativistic outflows rather than direct accretion, with direct measurements of the mass and energy budgets of individual bursts. The time-dependent wind model is a novel analytical framework for interpreting rapidly varying absorption lines in SMBH transients. The constraints on ejected mass, kinetic energy, and recurrence lifetime are valuable discriminants for the competing orbiter-disk collision and disk-instability models. The paper also makes falsifiable predictions for delayed radio and infrared signatures, which can be tested with ongoing monitoring. The dataset itself – the deepest high-resolution spectroscopy of any QPE – is a significant observational achievement.

Major objections (5)

[§3.2, Eq. (2)] The entire energy budget and mass-loss rate derivation rest on the assumption that the X-ray luminosity is purely powered by the wind kinetic energy with a constant radiative efficiency ε_X = L_X / (½ Ṁ_w v_w²). Although the authors note that ε_X is held constant in time (end of §3.2), they provide no physical justification for why this efficiency would be unchanging over the full factor-of-∼1500 luminosity rise and fall. If ε_X varies (e.g., because the dissipation mechanism changes as the wind expands), then Ṁ_w(t), the total ejected mass, and the kinetic energy are no longer determined by the data. The authors should discuss the plausibility of constant ε_X, explore the sensitivity of the results to time-varying ε_X, or provide an independent argument that the thermal continuum indeed originates from kinetic dissipation rather than accretion onto the SMBH.
[§3.2, §4] The fit statistics of the time-dependent wind model are C-stat/dof ≈ 2.0 and 1.7 for the two eruptions, which are significantly above unity and indicate substantial residuals. The paper does not discuss the nature of these residuals (e.g., whether they are systematic patterns in energy or time), nor does it compare simpler alternative models (e.g., a pure accretion-powered continuum with the same line absorption) on the same dataset. While the coarse grid precludes a rigorous goodness-of-fit assessment, the authors should explicitly address whether the residuals could be explained by the assumed form of L_X(t) (Eq. 8) or by the fixed-velocity, constant-ε_X assumptions, and whether the data actually prefer the kinetic-power model over a model where the continuum is not tied to Ṁ_w.
[§3.2, Table 3 (implied by grid description)] The parameter space is explored on an extremely coarse grid: two values of v_w, three of N_H, two of f_Ω, three of ε_X, and three of R_ξ/R_ph. The best-fit model is identified by the lowest C-stat among these 108 combinations, but no formal uncertainties are quoted on any of the wind parameters. Given that the difference in C-stat between the best and the next-best combinations can be large (e.g., v_w=0.1c yields ΔC ≥ 503), it is not clear whether the global minimum lies within the grid or whether different parameter combinations could produce similar spectral evolution. The authors should provide a more densely sampled grid or a Markov-chain exploration to demonstrate that the inferred values are not artifacts of the coarse grid, and they should report confidence intervals (e.g., via ΔC contours) for the key parameters.
[§3.2, below Eq. (3)] The authors argue that the photon-trapping time (r_tr/v_w ∼ 5 ks) is much shorter than the rise timescale (∼30 ks) and therefore ignorable. However, 5 ks is comparable to the time bin widths used in the spectral analysis (10 ks bins shifted by 1 ks). The early rise phase (t-t₀ < 10 ks) includes spectra where the trapping delay could smear the relationship between Ṁ_w(t) and L_X(t). This may affect the inferred density profile at small radii and the early-time ionization parameter. The authors should quantitatively estimate the impact of this delay on the model predictions, or at least note that it introduces systematic uncertainty in the first few bins.
[§3.2, Eqs. (4)–(7)] The model uses the same L_X(t) both to set the mass-loss rate (Eq. 3) and to compute the ionization parameter (Eq. 7). Because ξ(r,t) is expressed as a ratio of L_X(t) to L_X(t-r/v_w), its evolution is largely determined by the light curve shape and not by independent physics. The fact that the model reproduces the observed line centroid shifts is thus partly a restatement of the light curve shape, not a fully independent check. The authors should clarify what independent constraints the spectral data actually provide beyond the light-curve-driven evolution; for instance, the absolute value of log ξ (or the inferred column density N_H) is not fixed by L_X alone and does provide a check via the requirement that the wind be photoionized to the observed Fe charge states.

Minor objections (6)

[Fig. 5 and Table 1] Table 1 reports C-stat/dof values of 1.13 and 1.36 for the stacked spectra; while these are better than the time-dependent model fits, the error bars on the absorption column are generally asymmetric and large. The authors should comment on whether the stacked fits and the time-dependent model are statistically consistent given the different binning and degrees of freedom.
[§3.2, description of grid models] The parameter R_ξ / R_ph is defined as the line-forming radius ratio, but the physical interpretation of a constant ratio throughout the eruption is not discussed. Since the density profile evolves (Fig. 8), the location where a given ionization zone occurs may shift relative to the photosphere. The authors should briefly justify why R_ξ / R_ph is a reasonable fixed parameter.
[§4.1, Eq. (12)] The period-derivative estimate assumes that the ejected mass is 10⁻³ M⊙ and that the anisotropy factor f_∥ is of order 0.2. The order-of-magnitude agreement with the observed Ṗ is intriguing, but the authors should state that this is a speculative calculation and note that a full hydrodynamical treatment is required to assess whether the required anisotropy can be realized.
[Throughout] Several acronyms are used without definition on first use (e.g., C-stat/dof is introduced in §2 but re-used in §3.2; EMRI defined in §1 but referenced again in §4.1). A glossary of abbreviations would improve readability.
[Fig. 6 caption] The panel showing turbulence velocities (second from bottom) uses a logarithmic y-axis, but the label says 'v_turb/c'. In the leftmost portion of the early rise, the emission turbulence velocity appears to drop to zero, which may be an artifact of the binning or model degeneracy; the authors should comment on this.
[Fig. A.1] The collisionally ionized model quoted in the figure has kT = 0.20 keV, which is far below the typical temperatures needed to produce Fe XIX–XXIV. This comparison is already clearly in favor of photoionization, but the authors should note that the collisional model is a poor fit for this reason alone.

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The paper

The paper claims

QPEs in Ansky are powered by relativistic winds with v_w ~ 0.2c, ejecting ~10^{-3} Msun per burst and kinetically driving the X-ray emission.

The reading

Quasi-periodic eruptions (QPEs) are repeating X-ray flares from supermassive black holes, thought to be linked to tidal disruption events. The source Ansky shows the brightest and longest eruptions known. Using newly obtained XMM-Newton spectra, the authors detect blueshifted iron absorption and redshifted emission lines that evolve over the course of a few days. These features are classic P Cygni profiles produced by a dense, photoionized wind outflowing at about 0.2 times the speed of light. The same wind also kinetically powers the X-ray flare itself: a fraction (around 10%) of the wind's kinetic energy is converted into X-rays. The authors construct a time-dependent model where the wind density profile is set by the mass-loss rate at earlier times, accounting for the ionization changes as the wind expands. Fitting this model to the light curve and spectra yields an outflow rate of roughly 10^{-9} to 10^{-8} solar masses per second, ejecting about 10^{-3} solar masses per eruption with a kinetic energy of about 10^{49} erg. These numbers imply that if the source is a star-disk collision, the star can only survive a few decades. The cumulative energy is enough to shock the surrounding gas and may produce a delayed radio or infrared afterglow.

Extended reading notes

Core claim

The X-ray emission during QPEs in Ansky originates from a kinetically powered, mildly relativistic (v_w ~ 0.2c) wind-like outflow, with mass outflow rate ~10^{-9} to 10^{-8} Msun/s, per-eruption ejected mass ~10^{-3} Msun, kinetic energy >~10^{49} erg, and radiative efficiency L_X / E_K ~ 0.1. The time evolving P Cygni profiles are produced by the ionization response of this wind as it expands.

Load-bearing premise

The assumption that the X-ray luminosity is entirely powered by the wind kinetic energy with a constant radiative efficiency (Equation 2: L_X(t) = epsilon_X * 0.5 * Mdot_w(t) * v_w^2). This ties the mass-loss rate directly to the observed light curve and is not independently verified. If the efficiency varies in time or the X-ray luminosity has a different origin (e.g., accretion), the inferred Mdot and energetics are invalid.

Original abstract

Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs). They are an unprecedented type of structured, high-amplitude SMBH variability, but the physical origins of their regularity, timescales, energetics, and emission are uncertain. We present new XMM-Newton observations of the QPEs in ZTF19acnskyy/"Ansky", constituting the deepest observations of individual bursts in any source thus far. The X-ray spectra reveal time-evolving P Cygni profiles comprising blueshifted absorption and redshifted emission from L-shell transitions of Fe XIX-XXIV, with column densities $N_H\sim 10^{22-23}$ cm$^{-2}$ and bulk velocities of $|v_w/c|\sim 0.2$, indicating relativistic mass ejections during each eruption. We construct a time-dependent analytical model of a wind turning on to self-consistently compute its evolving luminosity and ionization properties, and find that the light curve and spectral lines can be simultaneously produced by a wide-angle outflow with $\dot{M}\sim 10^{-9}-10^{-8}\,M_\odot$ s$^{-1}$ kinetically powering the X-rays with an efficiency of $L_X/\dot{E}_K\sim 0.1$. For a covering fraction $f_\Omega\sim0.5$, each eruption ejects $\sim 10^{-3}\,M_\odot$ and $\gtrsim 10^{49}$ erg of kinetic energy, setting an upper bound on the QPE lifetime of $\lesssim1000$ bursts if the underlying mass reservoir is $\sim1 M_\odot$, and implying that the bursts may result in detectable multiwavelength signatures of reverberation and feedback. These measurements provide new quantitative constraints on QPE energetics, emission mechanisms, and the mass/energy they recycle into their circumnuclear environments, as well as an observational probe for direct comparison with physical models and hydrodynamical simulations of QPEs.

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arXiv listing abstract v1. Results and the main claim are underlined; show every role.

Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs). They are an unprecedented type of structured, high-amplitude SMBH variability, but the physical origins of their regularity, timescales, energetics, and emission are uncertain. We present new XMM-Newton observations of the QPEs in ZTF19acnskyy/``Ansky'', constituting the deepest observations of individual bursts in any source thus far. The X-ray spectra reveal time-evolving P Cygni profiles comprising blueshifted absorption and redshifted emission from L-shell transitions of Fe XIX-XXIV, with column densities $N_H\sim 10^{22-23}$ cm$^{-2}$ and bulk velocities of $|v_w/c|\sim 0.2$, indicating relativistic mass ejections during each eruption. We construct a time-dependent analytical model of a wind turning on to self-consistently compute its evolving luminosity and ionization properties, and find that the light curve and spectral lines can be simultaneously produced by a wide-angle outflow with $\dot{M}\sim 10^{-9}-10^{-8}\,M_\odot$ s$^{-1}$ kinetically powering the X-rays with an efficiency of $L_X/\dot{E}_K\sim 0.1$. Each eruption ejects $\sim 10^{-3}\,M_\odot$ and $\gtrsim 10^{49}$ erg of kinetic energy, setting an upper bound on the QPE lifetime of $\lesssim30$ years if the underlying mass reservoir is $\sim1 M_\odot$, and implying that the bursts may result in detectable multiwavelength signatures of reverberation and feedback. These measurements provide new quantitative constraints on QPE energetics, emission mechanisms, and the mass/energy they recycle into their circumnuclear environments, as well as an observational probe for direct comparison with physical models and hydrodynamical simulations of QPEs.

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What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs).	background 1.00	0.04	0.02	asserted 1.00
s1	They are an unprecedented type of structured, high-amplitude SMBH variability, but the physical origins of their regularity, timescales, energetics, and emission are uncertain.	gap 0.96	0.04	0.03	asserted 0.92
s2	We present new XMM-Newton observations of the QPEs in ZTF19acnskyy/``Ansky'', constituting the deepest observations of individual bursts in any source thus far.	contribution 0.75	0.96	0.03	asserted 1.00
s3	The X-ray spectra reveal time-evolving P Cygni profiles comprising blueshifted absorption and redshifted emission from L-shell transitions of Fe XIX-XXIV, with column densities $N_H\sim 10^{22-23}$ cm$^{-2}$ and bulk velocities of $\|v_w/c\|\sim 0.2$, indicating relativistic mass ejections during each eruption.	result 0.99	0.94	0.25	hedged possibility 0.64
s4	We construct a time-dependent analytical model of a wind turning on to self-consistently compute its evolving luminosity and ionization properties, and find that the light curve and spectral lines can be simultaneously produced by a wide-angle outflow with $\dot{M}\sim 10^{-9}-10^{-8}\,M_\odot$ s$^{-1}$ kinetically powering the X-rays with an efficiency of $L_X/\dot{E}_K\sim 0.1$.	result 0.66	0.97	0.37	asserted 1.00
s5	Each eruption ejects $\sim 10^{-3}\,M_\odot$ and $\gtrsim 10^{49}$ erg of kinetic energy, setting an upper bound on the QPE lifetime of $\lesssim30$ years if the underlying mass reservoir is $\sim1 M_\odot$, and implying that the bursts may result in detectable multiwavelength signatures of reverberation and feedback.	result 0.56	0.91	0.36	asserted 0.64
s6	These measurements provide new quantitative constraints on QPE energetics, emission mechanisms, and the mass/energy they recycle into their circumnuclear environments, as well as an observational probe for direct comparison with physical models and hydrodynamical simulations of QPEs.	interpretation 0.83	0.80	0.30	asserted 0.99

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 1.00.

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Figures

**Figure 1.** X-ray light curves of Ansky in 2025. (a): Long-term monitoring with NICER (black diamonds), Swift (red squares), and XMM-Newton (open circles). Open triangles denote upper limits and shaded bands mark the two eruptions observed by XMM, expanded in the lower panels. (b)-(c): Zoom-in of the XMM observations of quiescence (OBSIDs 0101/0301) and eruptions (OBSIDs 0201/0401). (d): XMM eruption light curves overlaid with their peaks aligned. The rise profiles are indistinguishable, while the eruptions diverge in their stochastic variability after the peaks. XMM-Newton data were obtained…

**Figure 2.** Stacked EPIC-pn spectrum of the quiescent state (OBSIDs 0101+0301; 164 ks total exposure), fit with a thermal disk blackbody model over 0.3–0.7 keV. The fitted model has kBTin = 64+4 −4 eV and LX = 1.9 × 1040 erg s−1 . secutive non-detections are combined into wider bands to increase sensitivity to low-amplitude variability. 3. RESULTS We show the 2025 X-ray light curve of Ansky in

**Figure 3.** Simultaneous XMM-Newton RGS and EPIC-PN spectra, stacked over the combined eruption rises (left) and peaks (right) of both observations. Upper panels show the data with single-blackbody continuum models. The best-fit blackbody temperatures kBT are annotated, and disagree by 3 eV between RGS and PN, likely due to instrument calibration differences. Lower panels show the data-to-model ratio, revealing the P Cygni profile near ∼ 1 keV that deepens from rise to peak. redward of the trough, near ∼0.9 keV. This combination of blueshifted absorption and redshifted emission is the classic…

**Figure 4.** Rest-frame transmission spectra of photoionized plasma with NH = 5 × 1022 cm−2 and vturb = 500 km s−1 irradiated by a 100 eV blackbody continuum. Increasing ξ shifts the lines to higher energies, which, for a broad unresolved line blend, can mimic the effect of a higher blueshift. emission+absorption model as the RGS data. Fitting the spectra with all parameters free is highly degenerate, so we iteratively fixed the outflow speed to determine the response of the other parameters. We tested 9 different assumed speeds, vw/c = {0, 0.05, 0.1, ..., 0.4}, holding them constant while leav

**Figure 5.** Model preference in the time-resolved fits. (a): Outflow velocity preference: for each window, ∆C(vw) = C(vw) − min C(v) measures how much worse each vw is than the best one. The minimum is flat over 0.1c − 0.2c and rises outside it, excluding both a static absorber and vw ≳ 0.25c. (b): reduced fit statistics comparing collisionally ionized to photoionized absorption. In nearly all windows the collisional ionization model is disfavored. emission. We show the comparison of fit statistics in Fig. 5b. The collisional model is worse in 85% of the 234 windows, by a median ∆C = 53 and by…

**Figure 6.** Time evolution of the wind model (Section 3.2) providing the best fit to our data (ϵX = 0.1, vw = 0.2c, fΩ = 0.5, NH = 5 × 1022, Rξ = 1.2Rph). Data are shown for both eruptions (OBSID 0201/0401 in black/blue). From top to bottom, we show time evolution of luminosity, photosphere temperature, ionization parameter at the line-forming radius, turbulent velocities of the absorption/emission components, and column densities of the absorption/emission components. rise PSDs are fully described by a smooth power-law increase. If we detrend the rise light curve by subtracting the best-fit…

**Figure 8.** Radial structure of the wind model throughout an eruption. From top to bottom, we show the time-evolving profiles of ion number density, optical depth, ionization parameter, and local diffusion time in the wind. The filled circles in each panel mark the photosphere radii, where the optical depth integrates to one. The shaded region in the third panel marks the range of ionization parameters which can form the observed Fe-L absorption features. variabilities of Fvar = 2.9 ± 0.2%/3.3 +0.4 −0.3% in the 0.25– 3 mHz band. The RMS variability rises smoothly as a function of energy, from…

**Figure 9.** Rapid variability diagnostics of the two eruptions (OBSID 0201/0401 are in black/blue). Left/center: PSDs of the rise/peak segments fit with power-law models. The dashed lines indicate the Poisson noise floor. For the rise light curves, we also show the PSD of the detrended light curve, indicating no variability is present apart from the power-law rise. Right: energy-resolved fractional variability in the 0.25–3 mHz band for the peak segments. The variability increases at higher energies. Wind-like relativistic outflow powering each QPE Rph ∼ 1014−15 cm kBTph ∼ 60 − 100 eV Rξ ≳ Rph…

**Figure 10.** Schematic illustration (not to scale) of the eruption geometry implied by our measurements. The system has a persistent accretion disk with kBTin ≈ 65 eV (

Showing 9 of the paper's 10 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:2608.28507 by the authors.

References

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What this paper does with the arXiv papers it cites

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

What it cites · 20 sentences without a confident label

Uses the method or tool of 6 papers

To characterize the profile, we fit the stacked RGS spectra with a two-component photoionized plasma of solar chemical abundance, characterized by the spectral model [ref] .

Systematic comparison of photoionised plasma codes with application to spectroscopic studies of AGN in X-rays · P Cygni profile during the eruptions · 1.00
We follow the treatment of [ref] and [ref] and normalize to fiducial values of $E_K,51=E_K/10^51$ erg, $n_cnm,1=n_cnm/10^1$ cm$^-3$, $ϵ_e,-1=ϵ_e/10^-1$, and $ϵ_B,-2=ϵ_B/10^-2$ for the fractions of shock energy in non-thermal electrons and magnetic fields, and adopt an electron index $p=2.5$.

Delayed Radio Flares in Tidal Disruption Events from Star-Disk Collision Outflows · Implications for reverberation and feedback · 0.98
We follow the treatment of [ref] and [ref] and normalize to fiducial values of $E_K,51=E_K/10^51$ erg, $n_cnm,1=n_cnm/10^1$ cm$^-3$, $ϵ_e,-1=ϵ_e/10^-1$, and $ϵ_B,-2=ϵ_B/10^-2$ for the fractions of shock energy in non-thermal electrons and magnetic fields, and adopt an electron index $p=2.5$.

Radio constraint on outflows from tidal disruption events · Implications for reverberation and feedback · 0.98

Compares with 4 papers

This picture agrees qualitatively with recent work modeling QPEs arising from the collisions of extended debris streams surrounding an EMRI orbiter with the SMBH accretion disk [ref] ; however, it is not yet clear whether other models (e.g. disk instabilities) are entirely unable to produce such behavior, making definitive model comparisons premature.

Star-Disk Collisions II: Debris Stream Dynamics and Implications for QPEs and Other Transients Near SMBHs · Conclusion · 0.92
This picture agrees qualitatively with recent work modeling QPEs arising from the collisions of extended debris streams surrounding an EMRI orbiter with the SMBH accretion disk [ref] ; however, it is not yet clear whether other models (e.g. disk instabilities) are entirely unable to produce such behavior, making definitive model comparisons premature.

2506.10096 · Conclusion · 0.92
For $M_∙∼10^6 M_⊙$, this is $30%$ of the Eddington luminosity, significantly larger than the $Ė_K/L_bol∼0.5$–$5%$ measured for ultrafast outflows in high-$L_Edd$ AGN, the regime generally regarded as sufficient for efficient coupling to the host [ref] .

Energy input from quasars regulates the growth and activity of black holes and their host galaxies · Implications for reverberation and feedback · 0.98

Cites as background 13 papers

While EMRI models show promise in explaining many QPE observables—particularly their regularity, timescales, rates, and energetics—there remain uncertainties regarding their radiation mechanisms [ref] , formation channels and evolution [ref] , mass and energy budgets [ref] , short- and long-term timing variations [ref] , and broader implications for dynamics in galactic nuclei [ref] .

Radiation-hydrodynamics of star-disc collisions: From system parameters to outflows and lightcurves · Introduction · 0.91
While EMRI models show promise in explaining many QPE observables—particularly their regularity, timescales, rates, and energetics—there remain uncertainties regarding their radiation mechanisms [ref] , formation channels and evolution [ref] , mass and energy budgets [ref] , short- and long-term timing variations [ref] , and broader implications for dynamics in galactic nuclei [ref] .

2506.10096 · Introduction · 0.91
While EMRI models show promise in explaining many QPE observables—particularly their regularity, timescales, rates, and energetics—there remain uncertainties regarding their radiation mechanisms [ref] , formation channels and evolution [ref] , mass and energy budgets [ref] , short- and long-term timing variations [ref] , and broader implications for dynamics in galactic nuclei [ref] .

2506.11231 · Introduction · 0.91

Discussion

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