Cosmic Web Ram-Pressure Stripping

• Cosmic web ram-pressure stripping is the removal of gas from low-mass halos by dynamic pressure from cosmic filaments, pancakes, and void walls.
• The process is quantified by comparing the external ram pressure with the halo's gravitational restoring force using analytical models adapted from ICM studies.
• Simulations and observations reveal its role in quenching star formation in isolated dwarfs and massive protocluster cores across diverse cosmic environments.

to=arxiv_search 亚历山大发json code omitted to=arxiv_search 久赢json code {"query":"id:(Zhou et al., 16 Jun 2026) OR id:(Benitez-Llambay et al., 2012) OR id:(Thompson et al., 2022) OR id:(Yang et al., 2022) OR id:(Luber et al., 18 Sep 2025) OR id:(Koppen et al., 2018)","max_results":10} Cosmic web ram-pressure stripping denotes hydrodynamical gas removal driven by gas associated with large-scale structure rather than only by the mature intracluster medium of a virialized cluster. In the narrow sense introduced for dwarf halos, the stripping agent is the moving cosmic web itself—especially filaments and large-scale pancakes that overtake low-mass halos outside massive hosts. In a broader but qualified usage, related stripping can occur in void walls, in low-density intergalactic or intra-group reservoirs, at filament intersections, and in dynamically young protocluster cores whose hot atmospheres are already sufficiently dense to displace cold gas before relaxed cluster assembly (Benitez-Llambay et al., 2012, Thompson et al., 2022, Yang et al., 2022, Luber et al., 18 Sep 2025, Zhou et al., 16 Jun 2026).

1. Definition and conceptual scope

The original formulation by Benítez-Llambay et al. identifies “cosmic web stripping” as a mechanism in which gaseous structures of the forming web—specifically filaments and especially large-scale pancakes—move relative to low-mass halos and remove their gas by ram pressure, while leaving the dark-matter halo largely intact. The mechanism is explicitly framed as a hydrodynamical environmental effect outside massive host halos, distinct from internal gas loss by supernova feedback and distinct from suppression by cosmic reionization (Benitez-Llambay et al., 2012).

Subsequent work has broadened the set of environments in which analogous physics appears. In void-wall simulations, the relevant driver is not a quasi-static dense ambient atmosphere of a cluster, but opposed large-scale converging cosmic-web flows on the two sides of a wall; haloes that have recently crossed the wall can encounter a headwind that both cuts off external gas accretion and partially strips halo gas (Thompson et al., 2022). In nearby observational work on WLM, the stripping medium is described more cautiously as an inter-galactic gaseous reservoir or IGM far from large galaxies, with possible association to the Local Void or Local Sheet rather than to a directly detected filament (Yang et al., 2022). In AGC 727130, the proposed stripping medium is diffuse gas associated with a junction of several DisPerSE filaments, a location expected to host shock-heated gas (Luber et al., 18 Sep 2025). In SPT2349$-$56-C26, the immediate agent is framed more narrowly as dense hot gas in a disturbed protocluster core rather than a generic filament alone; this makes the case highly relevant to broad, pre-virialized environmental stripping, but not a clean filament-only demonstration (Zhou et al., 16 Jun 2026).

The literature therefore supports two related usages. The narrow usage refers to stripping by the moving cosmic web outside massive virialized halos. The broader usage includes hydrodynamic stripping by dense gas associated with assembling structure—nodes, walls, groups, and protocluster cores—before the emergence of a mature low-redshift-style ICM. This suggests that the central physical distinction is not simply “cluster” versus “non-cluster,” but whether large-scale-structure gas can generate a ram pressure sufficient to overcome the restoring force of the affected galaxy or halo.

2. Pressure balance, response times, and analytical formulations

Across the literature, the core condition is the same competition between external dynamical pressure and internal restoring force. In the dwarf-halo formulation, the web exerts

$P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$

or, in the pancake notation,

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$

while the halo retains gas with a restoring pressure written schematically as

$P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$

Efficient stripping requires

$$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$

so that

$$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$

In the showcase event of Benítez-Llambay et al., a pancake velocity of about $300\ {\rm km\,s^{-1}}$ and a halo with $V_{200}\sim 40\ {\rm km\,s^{-1}}$ imply $\left(300/40\right)^2 \approx 56 \sim 60$, so gas roughly 60 times denser than the pancake can still be removed (Benitez-Llambay et al., 2012).

Disk-based treatments use a more explicit Gunn–Gott-style force balance. For WLM the criterion is written as

$$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$

with $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$0, $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$1, and $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$2 for $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$3 kpc (Yang et al., 2022). For the $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$4 protocluster galaxy C26, the minimum external pressure needed to overcome restoring gravity is

$P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$5

with exponential profiles

$P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$6

and ram pressure

$P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$7

Using $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$8, $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$9, $P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$0 kpc, and $P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$1 kpc, the paper derives

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$2

The conclusion is qualitative rather than a unique best-fit solution: for plausible ambient densities at $P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$3, substantial gas displacement is possible (Zhou et al., 16 Jun 2026).

A general analytical treatment is given by the kinematic framework of “Ram Pressure Stripping Made Easy.” There the relevant distinction is whether the ram-pressure pulse is long or short compared to the local vertical oscillation period,

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$4

In the long-pulse limit, the usual Gunn–Gott criterion is recovered:

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$5

In the short-pulse limit, the stripping outcome depends on the time-integrated ram pressure,

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$6

and escape requires

$P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$7

The formalism is deliberately general in $P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$8, but its calibration, orbital arguments, and typical pulse durations are cluster-specific; the paper explicitly warns that the cluster-based $P_{\rm ram} \propto \rho_{\rm p} V_{\rm p}^2,$9 Myr pulse-length intuition should not be imported unchanged to filament, sheet, or intragroup encounters (Koppen et al., 2018).

3. Low-mass halos in filaments, pancakes, and void walls

The canonical cosmic-web case concerns low-mass central halos during Local Group formation. Benítez-Llambay et al. used a constrained cosmological hydrodynamical simulation from the CLUES project, with an $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$0 Mpc parent box and a high-resolution region of $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$1 Mpc radius at $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$2, to show that Local Group-scale collapse generates a network of filaments and a prominent pancake by about $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$3. Galaxies 17, 30, and 50 all cross the pancake at roughly the same epoch and subsequently show strongly truncated star formation histories. Galaxy 30 loses most of its baryons abruptly between $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$4 and $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$5; afterward its virial mass more than doubles while its baryonic mass barely increases, and by $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$6 its baryon content is less than 10% of the universal expectation. The broader quenched dwarf population in that realization retains no more than $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$7 of the baryons expected from the cosmic baryon fraction. Galaxy 17 provides the clearest visualization: at $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$8 the pancake approaches rapidly, and by $P_{\rm gal} \propto \rho_{\rm gal}\, V_{200}^2.$9 much of the gaseous halo has been torn away, trailing toward the pancake in streams. A second requirement is also emphasized: the web structure must sweep enough gas column across the halo. For galaxy 17, the total pancake gas mass intersected by a cylinder of radius equal to the halo virial radius exceeds the halo gas mass by more than a factor of two (Benitez-Llambay et al., 2012).

The mechanism is strongly mass dependent. For a fixed web velocity, $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$0 rises steeply as halo mass decreases, so low-mass halos can be fully stripped while more massive ones remain only mildly affected. Because the interaction is hydrodynamical, the dark matter is not comparably altered: the halo’s virial mass can continue to grow after baryons are lost. The paper presents this as a mechanism for producing gas-poor, quenched, isolated dwarfs and for helping explain the scarcity of luminous dwarfs and the diversity of dwarf morphologies and star-formation histories, while also stressing that cosmic web stripping is complementary to reionization and feedback rather than a total substitute (Benitez-Llambay et al., 2012).

Void-wall stripping extends the same logic to a lower-density but dynamically specific environment. In hydrodynamical cosmological zoom simulations of 14 voids at $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$1, halo–gas flow was measured in a $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$2–$$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$3 shell with

$$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$4

The authors define “fast flow haloes” by $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$5 and “slow flow haloes” by $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$6. Out of 10,402 central haloes, 1,261 are fast-flow and 7,308 slow-flow, so fast-flow haloes make up 12.1% of the total sample, while slow-flow haloes comprise 70%. Fast-flow haloes are concentrated near walls: within $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$7 of a wall the fast-flow fraction rises to 22.9%, and if the criterion is relaxed to $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$8 then 18% of all void haloes and 33% near walls qualify. These haloes have recently crossed the void wall and are still moving away from it, while ambient gas from the neighboring void flows toward the wall in the opposite direction, producing a headwind. The predicted outcome is usually starvation plus partial stripping rather than complete denuding. For masses below a few $$\rho_{\rm web} v_{\rm rel}^2 \gtrsim \rho_{\rm gal} V_{200}^2,$$9, halo gas is heavily truncated but not totally removed; full stripping is rare in void walls. The simulations also show numerous jelly-fish-like haloes with one-sided gaseous tails aligned with the inferred flow direction (Thompson et al., 2022).

Taken together, the filament/pancake and void-wall results suggest that cosmic-web ram pressure is not a single morphology tied to a single density regime. It includes both relatively brief encounters with moving pancakes during anisotropic collapse and longer-lived headwind configurations produced by wall crossing and counterstreaming gas.

4. Observational candidate systems outside massive hosts

Observational evidence outside rich groups and clusters remains heterogeneous, but two nearby systems are particularly informative because both are far from the standard satellite-stripping geometry.

WLM is presented as an archetypal isolated, gas-rich field dwarf that nevertheless shows signatures of ongoing ram-pressure stripping. Using MeerKAT H I data, deep Subaru Suprime-Cam optical imaging, and Gaia EDR3 proper motions, the study identifies four significant, extended H I clouds—C1, C2, C3, and C4—lying $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$0 to $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$1 arcminutes northwest of WLM, corresponding to $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$2 to $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$3 kpc. Their total H I mass is $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$4, about $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$5 of the main body’s $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$6. The two innermost clouds are connected to the galaxy by a bridge, the stellar component lacks counterparts in the clouds, and the H I distribution is offset relative to the stellar distribution in the same direction as the trailing clouds. Gaia-based proper motions combined with the heliocentric radial velocity imply a total space velocity of about $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$7 with respect to the Milky Way center, and the trailing H I features align opposite to that motion. A Gunn–Gott estimate using $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$8 gives a minimum ambient density $$\frac{\rho_{\rm gal}}{\rho_{\rm web}} \lesssim \left(\frac{v_{\rm rel}}{V_{200}}\right)^2.$$9. The interpretation is deliberately cautious about nomenclature: the paper argues for an inter-galactic gaseous reservoir far from large galaxies, but does not directly identify the medium as cosmic-web gas in the strict sense (Yang et al., 2022).

AGC 727130 is a more explicitly cosmic-web candidate. It is a low-mass, gas-rich dwarf field galaxy with $300\ {\rm km\,s^{-1}}$0, $300\ {\rm km\,s^{-1}}$1, an H I radius of $300\ {\rm km\,s^{-1}}$2 kpc, and an optical radius of $300\ {\rm km\,s^{-1}}$3 kpc. VLA H I imaging shows a strongly asymmetric one-sided H I distribution extending well beyond the stellar disk, while the stellar body traced by Pan-STARRS appears comparatively undisturbed. The VLA 1.4 GHz continuum map yields a $300\ {\rm km\,s^{-1}}$4 upper limit on the star-formation rate of $300\ {\rm km\,s^{-1}}$5, and prior optical spectroscopy found no H$300\ {\rm km\,s^{-1}}$6 or other emission lines. The main tidal alternative is a nearby interacting dwarf pair at a projected separation of 60 kpc, but the inferred tidal radius is 30 kpc, much larger than the optical and H I radii, and the crossing time $300\ {\rm km\,s^{-1}}$7 Myr is about 15 times longer than the inferred tail formation timescale $300\ {\rm km\,s^{-1}}$8 Myr. DisPerSE reconstruction of the SDSS spectroscopic galaxy distribution places AGC 727130 at the intersection of several filaments, specifically at an intersection of three filaments in the discussion, and the Gunn–Gott estimate is evaluated against filament-gas conditions $300\ {\rm km\,s^{-1}}$9 and galaxy velocities of a few hundred km s$V_{200}\sim 40\ {\rm km\,s^{-1}}$0. The authors treat the system as a strong candidate rather than a definitive detection because the ambient medium is not directly observed and the ram-pressure estimate is order-of-magnitude (Luber et al., 18 Sep 2025).

These cases illustrate two observationally distinct but related regimes. WLM argues that ram-pressure stripping can occur well outside the immediate halo of a massive galaxy in a low-density intergalactic environment. AGC 727130 argues more specifically that a field dwarf at a filament junction may be stripped by diffuse gas associated with the cosmic web itself. In both, the strongest evidence is gas–star decoupling plus one-sided gaseous morphology; the weakest link is direct characterization of the stripping medium.

5. Protocluster-core stripping before relaxed virialization

At high redshift, the most extreme current case is SPT2349$V_{200}\sim 40\ {\rm km\,s^{-1}}$156-C26 in the SPT2349$V_{200}\sim 40\ {\rm km\,s^{-1}}$256 protocluster at $V_{200}\sim 40\ {\rm km\,s^{-1}}$3. The system is embedded in a compact, dense protocluster core containing roughly 30 dusty star-forming galaxies within $V_{200}\sim 40\ {\rm km\,s^{-1}}$4 kpc, and recent ALMA thermal Sunyaev-Zeldovich measurements indicate that hot intracluster gas is already present. The surrounding medium is described not as a mature relaxed ICM, but as an early, dense, hot intraprotocluster or intracluster medium in a dynamically young core, possibly with turbulence, shocks, winds, or bulk motions, together with giant gas streamers and diffuse gas in the core. The galaxy itself has a cometary stellar morphology: a compact head plus a $V_{200}\sim 40\ {\rm km\,s^{-1}}$5 kpc one-sided clumpy stellar tail, with a bright downstream knot at projected distance $V_{200}\sim 40\ {\rm km\,s^{-1}}$6 kpc. ALMA and JWST show that the gas morphology is decoupled from the stars. The [C II] peak is offset from the stellar head by $V_{200}\sim 40\ {\rm km\,s^{-1}}$7 relative to F444W, or $V_{200}\sim 40\ {\rm km\,s^{-1}}$8 kpc, and $V_{200}\sim 40\ {\rm km\,s^{-1}}$9 relative to F200W, or $\left(300/40\right)^2 \approx 56 \sim 60$0 kpc. The dust continuum peak is also offset but less so: $\left(300/40\right)^2 \approx 56 \sim 60$1 ($\left(300/40\right)^2 \approx 56 \sim 60$2 kpc) relative to F444W and $\left(300/40\right)^2 \approx 56 \sim 60$3 ($\left(300/40\right)^2 \approx 56 \sim 60$4 kpc) relative to F200W. From [C II], the full cold-gas reservoir is estimated as $\left(300/40\right)^2 \approx 56 \sim 60$5, with $\left(300/40\right)^2 \approx 56 \sim 60$6 and $\left(300/40\right)^2 \approx 56 \sim 60$7; the tail therefore contains at least 55% of the total [C II] emission and more than half of the observed cold-gas reservoir (Zhou et al., 16 Jun 2026).

The kinematic and geometric evidence favors stripped gas rather than a conventional merger. The [C II] position–velocity diagram shows a continuous velocity gradient from the head toward the downstream knot, with the gas kinematically connected without a clearly detached component. [N II] lies on both flanks of the tail rather than along the [C II] ridge, and is interpreted as ionized interface layers around displaced cold gas interacting with a surrounding hot medium. The stellar tail is one-sided and aligned with the cluster-centric axis: the measured tail PA is $\left(300/40\right)^2 \approx 56 \sim 60$8, nearly identical to the cluster-centric axis defined by the tSZ signal ($\left(300/40\right)^2 \approx 56 \sim 60$9), and nearly perpendicular to the direction to the nearest neighboring galaxy ($$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$0). The authors argue that gravitational disturbance should affect stars and gas more similarly, whereas C26 shows strong decoupling between stellar and gaseous distributions and differential displacement among ISM phases. A major merger is disfavored because the downstream knot contains $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$1 of the stellar mass of the head, while the galaxy also shows only modest star formation and very low CO excitation, with $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$2 (Zhou et al., 16 Jun 2026).

The evolutionary significance of the system is unusually strong. The head has $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$3 and $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$4, with $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$5, relatively low for a main-sequence galaxy at $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$6. The authors argue that once more than half of the gas is removed, the restoring force of the remaining head is reduced, so stripping should continue. They describe C26 as an intermediate stage in motion through the $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$7-$$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$8 plane from a gas-rich main-sequence-like state toward a gas-poor, quiescent-like state at roughly fixed stellar mass. Their abstract conclusion is explicit: RPS can remove most of the cold gas from massive galaxies in dense protocluster cores as early as $$\rho_{igm}v^2 \geq 2 \pi G \Sigma_{\rm tot} \Sigma_g ,$$9, providing a direct hydrodynamic pathway for environmental quenching at $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$00. For the narrower question of cosmic-web stripping, however, the case remains qualified: it is direct evidence for severe stripping in a dynamically young assembling overdensity, but not direct evidence for stripping by a generic low-density filament well outside a core (Zhou et al., 16 Jun 2026).

6. Implications, limitations, and interpretive boundaries

A consistent implication across these studies is that hydrodynamic environmental processing need not wait for infall into a mature cluster. Low-mass halos can lose baryons to pancakes and filaments during anisotropic collapse, void-wall haloes can be starved and partially stripped by counterstreaming gas, isolated dwarfs can show ram-pressure signatures in low-density extra-halo environments, filament-junction dwarfs may undergo slow gas loss outside any massive host, and dense protocluster cores can already remove most of the cold gas from massive galaxies at $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$01 (Benitez-Llambay et al., 2012, Thompson et al., 2022, Yang et al., 2022, Luber et al., 18 Sep 2025, Zhou et al., 16 Jun 2026).

The interpretive strength of the evidence is uneven. The dwarf-halo cosmic-web mechanism of Benítez-Llambay et al. is demonstrated in one high-resolution Local Group simulation rather than a large statistical sample. The void-wall study analyzes 14 relatively small voids at $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$02, omits star formation and feedback by design, and therefore emphasizes gas accretion and stripping rather than direct SFR histories. The WLM case depends on an uncertain 3D velocity relative to the stripping medium and on an ambient medium that is inferred rather than directly detected. AGC 727130 lacks direct detection of the proposed filament gas, and the authors explicitly present it as a candidate case. C26 is a single-object case study; its local ambient density and relative velocity are not directly measured, and the stripping calculations are plausibility arguments rather than a full dynamical reconstruction (Benitez-Llambay et al., 2012, Thompson et al., 2022, Yang et al., 2022, Luber et al., 18 Sep 2025, Zhou et al., 16 Jun 2026).

There is also an important boundary in terminology. If “cosmic web ram-pressure stripping” is used narrowly for stripping by relatively low-density filaments or pancakes outside cluster cores, then the 2012 dwarf-halo work and the void-wall and AGC 727130 studies are the most direct exemplars. If the term is used more broadly to include dense gas associated with assembling nodes, sheets, groups, and protoclusters before relaxed virialization, then the C26 event is highly relevant because it demonstrates that severe ram-pressure stripping can occur in dynamically young structure at very high redshift (Zhou et al., 16 Jun 2026).

Finally, the analytical framework most often used to estimate stripping remains a first-order tool rather than a dedicated cosmic-web theory. The pulse-based treatment of ram pressure in terms of $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$03, $P_{\rm ram} \sim \rho_{\rm web} \, v_{\rm rel}^2,$04, and the comparison with the galaxy’s restoring force is general in form, but it was calibrated for cluster ICM stripping of disk H I and transfers most naturally to direct disk stripping rather than to earlier removal of diffuse CGM. A plausible implication is that the framework is best used to ask whether cosmic-web gas can plausibly reach the stripping threshold, while detailed outcomes in filaments, walls, and protoclusters still depend on geometry, multiphase structure, response times, and whether the dominant effect is catastrophic removal, partial truncation, or starvation (Koppen et al., 2018).