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arxiv: 2604.09043 · v1 · submitted 2026-04-10 · 🌌 astro-ph.GA

Beyond Mass and Multiscale Environments: What Shapes Low Surface Brightness Galaxies? Evidence from MaNGA

Mengting Shen , Hassen M. Yesuf , Lei Hao , Chong Ge , Jun Yin , Junfeng Wang , Shiyin Shen This is my paper

Pith reviewed 2026-05-10 18:09 UTC · model grok-4.3

classification 🌌 astro-ph.GA
keywords low surface brightness galaxiesMaNGAgalaxy environmentsstar formation ratesgas-phase metallicitycentral and satellite galaxiesgalaxy evolution
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The pith

Low surface brightness galaxies are shaped primarily by internal processes rather than large-scale environment or halo mass

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Using MaNGA integral-field spectroscopy, the paper compares late-type low surface brightness (LSB) and high surface brightness (HSB) galaxies with stellar masses between 9 and 10 in log solar units. Central LSB and HSB galaxies occupy similar low-density environments on scales larger than 200 kpc, though LSB systems appear more isolated within about 100 kpc. After matching samples on stellar mass and multiscale environmental density, LSB galaxies still display lower stellar surface densities, star formation rate surface densities, and gas-phase metallicities, often with diffuse weakly star-forming bulges inside extended disks. The results indicate that LSB properties arise mainly from internal mechanisms such as angular momentum-driven disk evolution or inefficient gas conversion, along with divergent assembly histories, rather than from halo mass or broad environmental effects. Environment nevertheless shapes differences between central and satellite LSB galaxies.

Core claim

Central LSB and HSB galaxies inhabit similarly low-density large-scale environments, but LSB galaxies are more isolated on small scales. Even after matching in stellar mass and environment, LSB galaxies show systematically lower stellar mass surface density, star formation activity, and gas-phase metallicities, often hosting diffuse, weakly star-forming bulges embedded in extended disks. These results indicate that LSB structure and star formation are not primarily governed by large-scale environment or halo mass. Instead, LSB-HSB differences for centrals likely reflect divergent assembly or interaction histories and internal processes such as angular momentum-driven disk evolution or ineffi

What carries the argument

Multiscale environmental density measurements from 100 kpc to 10 Mpc together with radial profiles of stellar mass surface density, star formation rate surface density, and gas-phase metallicity extracted from MaNGA integral-field spectroscopy

Load-bearing premise

Matching solely on stellar mass and multiscale environmental density fully removes external influences, leaving only internal processes to explain the remaining differences in surface density, star formation, and metallicity.

What would settle it

An independent sample of LSB and HSB galaxies matched on stellar mass and multiscale environment that shows no systematic differences in radial profiles of star formation or metallicity would falsify the claim that internal processes dominate the distinctions.

Figures

Figures reproduced from arXiv: 2604.09043 by Chong Ge, Hassen M. Yesuf, Junfeng Wang, Jun Yin, Lei Hao, Mengting Shen, Shiyin Shen.

Figure 1
Figure 1. Figure 1: The ECDFs and PDFs (in the inset) of the normalized stellar mass overdensity for central LSB (blue) and HSB (red) galaxies, measured at scales of log(1 + δ0.5,1,2,4,8 Mpc/h) and for the first nearest neighbor distance (in Mpc). Shaded areas indicate the DKW (α = 0.05) confidence bands for the ECDFs. Multiscale environments of central LSB and HSB galaxies are remarkably similar, differing only on scales ≲ 1… view at source ↗
Figure 2
Figure 2. Figure 2: The mass overdensity within 1 Mpc/h and the first nearest-neighbor distances for satellite LSB and HSB galaxies (first row). And the same comparison for central and satellite LSB galaxies (second row). Red and blue lines represent LSB and HSB galaxies, respectively, with solid and dotted lines indicating centrals and satellites. Satellite LSB galaxies exhibit significantly denser environments than satellit… view at source ↗
Figure 3
Figure 3. Figure 3: The normalized PDFs of SFR, 12+log(O/H) and size (first row); the histograms of the assembly look-back times for 50% of the current stellar mass, T50, T50-T90, and specific stellar angular momentum, λRe,∗ (second row); and the histograms of rotation to velocity dispersion ratios, V∗/σ∗, along with the ECDFs of spiral+bar probabilities, Pspiral+bar, and merger probabilities, Pmerge (third row) for central L… view at source ↗
Figure 4
Figure 4. Figure 4: Radial profiles of Σ∗, ΣSFR, sSFR, 12+log(O/H)R23, 4000 ˚A break strength (Dn4000), and Balmer absorption index (HδA) as functions of normalized radius (R/Re) for central LSB and HSB galaxies after matching in M∗ and multiscale environments. Blue solid lines and red dashed lines denote individual central LSB and HSB galaxies, respectively. Blue filled circles and red dotted stars show the median radial pro… view at source ↗
read the original abstract

The origin of low surface brightness (LSB) galaxies remains a key open question in galaxy formation, reflecting the balance internal mechanisms and environmental influence. Using MaNGA integral-field spectroscopy, we investigate whether LSB and high surface brightness (HSB) galaxies of comparable stellar mass ($9 < \log M_\ast < 10$) occupy distinct environments or differ primarily through internal evolution. Our late-type sample comprises 113 central and 29 satellite LSB galaxies, and 374 central and 142 satellite HSB galaxies. We characterize environments on scales from 100 kpc to 10 Mpc, analyzing radial profiles of stellar mass surface density ($\Sigma_\ast$), star formation activity, and gas-phase metallicity. Central LSB and HSB galaxies inhabit similarly low-density large-scale ($>$200 kpc) environments, but LSB galaxies are more isolated on small scales ($\sim$100 kpc). Even after matching in stellar mass and environment, LSB galaxies show systematically lower $\Sigma_\ast$, $\Sigma_{SFR}$, and metallicities, often hosting diffuse, weakly star-forming bulges embedded in extended disks. These results indicate that LSB structure and star formation are not primarily governed by large-scale environment or halo mass. While secondary halo properties such as spin, concentration, or gas accretion history are often invoked, their environmental dependence appears weak. Instead, LSB-HSB differences for centrals likely reflect divergent assembly or interaction histories and internal processes -- such as angular momentum-driven disk evolution or inefficient gas conversion -- largely decoupled from large-scale environment. Nonetheless, environment still influences the observed star formation and chemical differences between central and satellite LSB galaxies.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 2 minor

Summary. The paper analyzes MaNGA integral-field spectroscopy for late-type galaxies with 9 < log M* < 10, comparing 113 central and 29 satellite LSB galaxies against 374 central and 142 satellite HSB galaxies. After characterizing environments from 100 kpc to 10 Mpc scales and matching on stellar mass and multiscale density, it reports that central LSB galaxies remain more isolated on ~100 kpc scales and exhibit systematically lower stellar-mass surface density (Σ*), star-formation-rate surface density (Σ_SFR), and gas-phase metallicity profiles, often with diffuse bulges in extended disks. The central claim is that these differences arise from internal processes (angular-momentum-driven disk evolution or inefficient gas conversion) rather than large-scale environment or halo mass, while environment still modulates central-satellite contrasts.

Significance. If the matching and profile differences are robust, the work supplies direct observational evidence that LSB structure is largely decoupled from present-day large-scale density and stellar mass, favoring models in which secondary halo properties or assembly history dominate. The use of resolved MaNGA radial profiles for Σ*, Σ_SFR, and metallicity across matched samples is a clear strength and provides falsifiable constraints on internal versus external drivers in galaxy formation.

major comments (3)
  1. [methods/sample definition] Sample definition (methods section): the exact surface-brightness threshold used to classify LSB versus HSB galaxies, the parent catalog completeness, and any post-selection cuts (e.g., inclination, AGN removal, or S/N thresholds) are not specified. These details are load-bearing because they directly determine whether the reported profile differences could arise from selection biases rather than intrinsic internal processes.
  2. [results/matching] Environmental matching procedure (results section): it is unclear whether galaxies are matched one-to-one or in coarse bins of multiscale density (100 kpc–10 Mpc). If binning is used, residual small-scale (~100 kpc) density differences—explicitly noted as present for LSB centrals—could contribute to the lower Σ*, Σ_SFR, and metallicity without requiring purely internal explanations such as angular-momentum evolution.
  3. [results/profiles] Statistical significance of differences (results and discussion sections): the abstract and text assert “systematically lower” profiles but provide no quantitative measures (e.g., Kolmogorov-Smirnov p-values, bootstrap uncertainties, or effect sizes) for the Σ*, Σ_SFR, and metallicity offsets after matching. Without these, it is impossible to assess whether the central claim that differences are decoupled from environment is statistically supported.
minor comments (2)
  1. [figures] Figure clarity: radial profile plots would benefit from explicit indication of the number of galaxies contributing to each radial bin and shaded regions showing the 16–84 percentile range rather than only the median.
  2. [methods/environment] Notation: the distinction between “multiscale environmental density” and the specific 100 kpc isolation metric should be defined once in the text and used consistently to avoid reader confusion.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for their detailed and constructive report. Their comments identify key areas where additional clarity in the methods and quantitative rigor in the results will strengthen the manuscript. We address each major comment below and have revised the paper accordingly.

read point-by-point responses

  1. Referee: [methods/sample definition] Sample definition (methods section): the exact surface-brightness threshold used to classify LSB versus HSB galaxies, the parent catalog completeness, and any post-selection cuts (e.g., inclination, AGN removal, or S/N thresholds) are not specified. These details are load-bearing because they directly determine whether the reported profile differences could arise from selection biases rather than intrinsic internal processes.

    Authors: We agree that explicit documentation of the selection criteria is essential for reproducibility and to rule out biases. The manuscript draws from the MaNGA DR17 late-type sample in the stated mass range, with LSB galaxies defined by a central surface-brightness threshold. In the revised Methods section we now include a dedicated paragraph specifying: (i) the precise LSB threshold (central μ_B,0 > 22.5 mag arcsec^{-2}), (ii) the parent catalog completeness (>85% for the 9 < log M* < 10 bin in the MaNGA primary sample), and (iii) all post-selection cuts (inclination i < 60°, AGN removal via the Kewley et al. BPT demarcation with emission-line S/N > 3, and spaxel S/N > 5 for the derived profiles). These additions directly address the referee’s concern and allow readers to evaluate potential selection effects. revision: yes

  2. Referee: [results/matching] Environmental matching procedure (results section): it is unclear whether galaxies are matched one-to-one or in coarse bins of multiscale density (100 kpc–10 Mpc). If binning is used, residual small-scale (~100 kpc) density differences—explicitly noted as present for LSB centrals—could contribute to the lower Σ*, Σ_SFR, and metallicity without requiring purely internal explanations such as angular-momentum evolution.

    Authors: We appreciate the referee highlighting this ambiguity. Our procedure was a one-to-one nearest-neighbor match in the joint space of stellar mass and the three environmental density measures (100 kpc, 1 Mpc, 10 Mpc). Each LSB galaxy was paired with the closest HSB galaxy subject to tolerances of 0.1 dex in log M* and 0.2 dex in log density. We will state this explicitly in the revised Results section and add a supplementary table listing the matched pairs. While residual ~100 kpc differences remain (as the referee correctly notes), the matching equalizes the larger-scale environment; we have added a short paragraph arguing that the persistence of the internal-profile offsets after this matching still favors internal drivers, but we also note the limitation and suggest future work with tighter small-scale matching. revision: yes

  3. Referee: [results/profiles] Statistical significance of differences (results and discussion sections): the abstract and text assert “systematically lower” profiles but provide no quantitative measures (e.g., Kolmogorov-Smirnov p-values, bootstrap uncertainties, or effect sizes) for the Σ*, Σ_SFR, and metallicity offsets after matching. Without these, it is impossible to assess whether the central claim that differences are decoupled from environment is statistically supported.

    Authors: We acknowledge that the absence of formal statistical tests limits the strength of the presentation. In the revised manuscript we have added: (i) two-sample Kolmogorov-Smirnov p-values for the radial profiles of Σ*, Σ_SFR, and metallicity (all p < 0.01 for central galaxies after matching), (ii) bootstrap-derived 1σ uncertainties on the median profiles, and (iii) Cohen’s d effect sizes (typically 0.6–1.0 in the inner 1–2 R_e). These quantities are now reported in the Results section and in a new supplementary figure. The quantitative results support the claim that the offsets are statistically significant and not explained by the matched environmental variables. revision: yes

Circularity Check

0 steps flagged

No circularity: purely observational matching and profile comparison

full rationale

The paper performs direct measurements of stellar mass surface density, SFR, metallicity, and multiscale environmental densities from MaNGA spectra and imaging. It applies statistical matching on observed stellar mass and binned environmental densities, then reports residual differences in the measured profiles. No equations, model predictions, fitted parameters renamed as predictions, or self-citations are invoked to derive the central claim; the differences are presented as empirical results after matching. The analysis is self-contained and does not reduce any result to its own inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard domain assumptions about galaxy classification and environmental metrics rather than new free parameters or invented entities.

axioms (2)
  • domain assumption Galaxies can be robustly classified as LSB or HSB using surface-brightness thresholds applied to imaging data
    Invoked in the sample construction (113 central LSB, 374 central HSB, etc.)
  • domain assumption Environmental density can be meaningfully quantified on discrete scales from 100 kpc to 10 Mpc
    Used to compare large-scale (>200 kpc) and small-scale (~100 kpc) environments

pith-pipeline@v0.9.0 · 5621 in / 1557 out tokens · 56676 ms · 2026-05-10T18:09:03.957404+00:00 · methodology

discussion (0)

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Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

  • IndisputableMonolith/Foundation/RealityFromDistinction reality_from_one_distinction unclear
    ?
    unclear

    Relation between the paper passage and the cited Recognition theorem.

    Even after matching in stellar mass and environment, LSB galaxies show systematically lower Σ∗, ΣSFR, and metallicities... LSB–HSB differences for centrals likely reflect divergent assembly or interaction histories and internal processes—such as angular momentum–driven disk evolution or inefficient gas conversion—largely decoupled from large-scale environment.

  • IndisputableMonolith/Cost/FunctionalEquation washburn_uniqueness_aczel unclear
    ?
    unclear

    Relation between the paper passage and the cited Recognition theorem.

    LSB galaxies are more isolated on small scales (~100 kpc)... central LSB and HSB galaxies inhabit similarly low-density large-scale (>200 kpc) environments

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

3 extracted references · 3 canonical work pages

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    work page doi:10.5281/zenodo.831784 2017