{"id":"e0eab140-4c05-4cff-9022-fdd008fefc7c","arxiv_id":"2507.20822","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"Satellite galaxies at z < 0.5 show ~0.5 dex suppressed star formation relative to isolated centrals at fixed stellar mass, strongest in high-mass halos, with satellite passive fractions rising 10-15% over the last 5 Gyr.","lead":"Comparing two surveys that use the same analysis machinery, this paper finds that satellite galaxies form stars about 0.5 dex less actively than isolated galaxies of the same stellar mass, with the largest suppression in the most massive halos. It also reports that this suppression grows over the last 5 billion years, with satellite passive fractions rising by roughly 10 to 15 percent.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Claim (iii) is not robust to the paper's own alternative passive-galaxy selection: the DEVILS-to-GAMA-mid increase disappears, leaving only a two-bin, ~1 Gyr GAMA trend rather than a 5 Gyr evolution.","rationale":"The reader's weakest assumption concerns the unpublished DEVILS group catalogue and its comparability with GAMA. That is a legitimate reproducibility and validation concern, but the more decisive issue is internal: the paper itself shows that the headline 'increase over the last 5 Gyr' is sensitive to the passive-galaxy selection method. With a reasonable alternative selection, the only remaining increase is between the two GAMA bins, which span roughly 1.2 Gyr rather than 5 Gyr. For the SFR offsets, the DEVILS bin is within 1 sigma of the GAMA mid-redshift bin in every halo-mass range, so the apparent 5 Gyr trend is not statistically secure. This reinforces the reader's conditional verdict rather than overturning the paper: the 0.5 dex suppression and halo-mass dependence remain credible, but the time-evolution claim needs softening or additional validation. I agree with the reader's overall CONDITIONAL assessment, though the specific load-bearing weakness I identify is the passive-selection fragility already documented in the text rather than the unpublished catalogue itself.","tokens_in":24506,"tokens_out":9239,"duration_ms":93916,"concrete_test":"Recompute the satellite passive fractions and SFR offsets for all three redshift bins under (a) the alternative fixed 1-dex passive selection described in Section 3.2, and (b) a fit restricted to the two GAMA bins (z=0.001-0.1 and 0.1-0.2), with the DEVILS bin omitted. If the lookback-time slope of the satellite-isolated offset or the passive-fraction difference is not significantly positive in (a) or (b), claim (iii) should be downgraded to a low-redshift (z<0.2) effect and the abstract revised accordingly.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The abstract's time-evolution claim (iii) is not robust to the paper's own alternative passive-galaxy selection, and the high-redshift anchor is individually consistent with no evolution. In Section 3.2 the authors report that if passive galaxies are selected with a simpler fixed 1 dex below the SFS instead of the 2 sigma evolving-width line, 'the weak increase in satellite passive fraction between the 0.3<z<0.5 bin and 0.1<z<0.2 bin is removed'; only the GAMA z~0.15 to z~0.05 increase survives. Thus the '~10-15% over the last ~5 Gyr' headline depends on a single DEVILS bin and on one particular, non-unique definition of 'passive.' The SFR-offset version is similarly fragile: in Table 1, DEVILS 0.3<z<0.5 differs from GAMA 0.1<z<0.2 by only 0.09+/-0.18 (13<logMhalo<14), 0.13+/-0.18 (14-15), and 0.11+/-0.14 (>13), all within 1 sigma. So the 'increase with time' is, with current errors, a two-bin GAMA trend extrapolated backward rather than a demonstrated 5 Gyr evolution. Claims (i) and (ii) - the ~0.5 dex suppression and stronger suppression in massive halos - are well supported; the weak point is specifically the growth-with-time statement.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper uses DEVILS D10 (0.3 < z < 0.5) and GAMA (0 < z < 0.2), with ProSpect-derived stellar masses and SFRs and friends-of-friends group catalogues, to measure the SFR offset between satellite and isolated central galaxies, its dependence on halo mass, and the time evolution of satellite passive fractions. The abstract claims approximately 0.5 dex suppression in log10(SFR) for satellites at fixed stellar mass, stronger suppression in more massive halos (up to ~1 dex), and an increase in suppression and passive fraction with time over the last ~5 Gyr. The analysis uses running medians, 5,000-realisation Monte Carlo error bands, and comparisons with literature passive fractions and several simulations.","tokens_in":24807,"tokens_out":7041,"duration_ms":73657,"significance":"If the central claims hold, this would be one of the first direct, methodologically homogeneous measurements of satellite quenching across 0 < z < 0.5, using the same SED-fitting code and the same FoF group-finding approach for both surveys. The ~0.5 dex suppression and the halo-mass dependence are visible in the figures and supported by the Monte Carlo bands, so these parts are a useful and credible contribution. The main weakness is the time-evolution claim, which rests on a single DEVILS redshift bin and is sensitive to the passive-galaxy selection definition; this part needs to be either made quantitatively robust or substantially toned down. The comparison with simulations is a useful consistency check, though the different passive selection used for simulations complicates the normalisation comparisons.","major_comments":[{"comment":"The headline claim (iii) that satellite suppression and passive fraction increase with time over the last ~5 Gyr is not supported by the quoted numbers. In Table 1 the DEVILS 0.3<z<0.5 offsets are consistent within 1 sigma with the GAMA 0.1<z<0.2 offsets (for log Mhalo > 13: 0.58 ± 0.14 versus 0.69 ± 0.02; for 13 < log Mhalo < 14: 0.46 ± 0.18 versus 0.55 ± 0.02; for 14 < log Mhalo < 15: 0.85 ± 0.17 versus 0.98 ± 0.05). The SFR-offset evolution is therefore at most a two-bin GAMA trend extrapolated backward, not a demonstrated 5 Gyr trend. The passive-fraction version is similarly fragile: Section 3.2 reports that with a fixed 1 dex below the SFS selection, the weak increase between the 0.3<z<0.5 and 0.1<z<0.2 bins is removed, leaving only the GAMA 0.001<z<0.1 to 0.1<z<0.2 increase. I ask the authors to either quote the formal significance of the three-point slope in Figure 4, including the covariance between points, or reframe claim (iii) as a low-redshift GAMA trend with a DEVILS anchor consistent with no evolution, and adjust the abstract and summary accordingly.","section":"Section 3.2, Table 1, Figure 4"},{"comment":"The entire comparison rests on the assumption that the DEVILS D10 FoF group catalogue (Bravo et al., in preparation) recovers halos and assigns central/satellite status with the same fidelity as GAMA's public G3C catalogue, and that the M_halo ~ A R50 sigma^2 proxy is calibrated identically at both epochs. The paper states that Bravo et al. optimise linking lengths and test recovery on Shark light cones, but no recovery statistics, purity/completeness as a function of redshift, or calibration of A are presented here. Given that the DEVILS group catalogue is not yet public, the redshift evolution in Section 3.2 could in principle be an artefact of redshift-dependent group completeness or halo mass bias. Please include quantitative validation from the mocks (e.g., satellite classification completeness and halo mass bias versus redshift), or explicitly model this systematic in the error budget.","section":"Section 2.1.2"},{"comment":"The simulations are compared to the observations using a different passive-galaxy definition: the simulations use log10(sSFR/yr^-1) < -11 + 0.5z following Wright et al. (2022), while the observations use a redshift-dependent 2 sigma offset from the fitted star-forming sequence (Appendix A). Since the claimed simulation ranking (e.g., SIMBA 2-3 sigma above, EAGLE 2-3 sigma below the observed trend) is stated in normalisation, the selection mismatch can masquerade as a difference in feedback physics. Either apply the identical passive selection to the simulations and observations, or restrict the simulation comparison to slopes and state this limitation explicitly when quoting normalisation offsets.","section":"Section 3.2.2, Figures 7 and 8"}],"minor_comments":[{"comment":"The phrase 'identical manner' should be qualified: the text itself notes that GAMA and DEVILS have different photometric depths and rest-frame coverage, which is a caveat on the claimed reduction of methodology bias.","section":"Sections 2.1.1 and 2.2.1"},{"comment":"Figure 3 does not show the Monte Carlo error polygons that appear in Figure 2, even though the text uses Figure 3 to argue that the offsets are similar across epochs; adding the error ranges or referring explicitly to Table 1 would make this claim easier to verify.","section":"Figure 3"},{"comment":"The text says 'We do see tentative hints' of an increasing suppression and later says the offset increase is 'significant when considering the calculated errors'; these two statements are in tension and should be replaced with one significance statement tied to a specific number.","section":"Section 3.1"},{"comment":"The formatting of the asymmetric errors in Table 2 is difficult to read; a standard f_plus/f_minus layout or separate error columns would improve clarity.","section":"Table 2"},{"comment":"The Summary repeats claim (iii) as established ('this suppression increases over the last ~5 Gyr') even though Section 3.2 advises caution about the selection dependence; harmonise the language with the actual significance.","section":"Summary and Conclusions"}],"recommendation":"major_revision","confidential_remarks":"The paper is within the scope of the journal and the observational dataset is valuable. The main issue is that the abstract's time-evolution claim is stronger than the current data support, but this should be fixable by a re-analysis with explicit significance estimates and a more cautious framing. No concerns about citation practice or novelty disclosure."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Here's my take. The paper is worth reading for the central result: satellite SFR suppression of ~0.5 dex at fixed stellar mass, with stronger suppression (~1 dex) in more massive halos, measured with the same SED fitting and group-finding in GAMA and DEVILS. That is a genuinely useful homogeneous benchmark, and the Monte Carlo error treatment is careful. The authors are also honest about the fragility of their passive-fraction selection, which matters because the headline time-evolution claim does not survive their own robustness check.\n\nThe soft spot is claim (iii). The abstract says suppression increases with time and passive fractions grow by 10-15% over 5 Gyr. But Section 3.2 reports that with a simpler fixed 1 dex passive cut, the DEVILS-to-GAMA-mid increase vanishes; only the low-redshift GAMA trend remains. Table 1 shows the DEVILS 0.3<z<0.5 offsets are within ~0.1 dex of GAMA 0.1<z<0.2, all consistent at 1 sigma. So the 'evolution' is essentially a two-bin GAMA trend extrapolated backward, anchored by one DEVILS bin. That should be downgraded to a tentative hint, not a headline claim. Also, the simulation comparison uses a different passive definition for the simulations (fixed sSFR cut) than for the data (2 sigma SFS), so the normalisation comparisons are not apples-to-apples. Finally, the DEVILS group catalogue is still in prep; the analysis depends on it, so replication needs the data release.\n\nMinor issues: the literature comparison mixes methods and redshifts, but they acknowledge that. The central claims (i) and (ii) are robust and consistent with earlier work.\n\nVerdict: this deserves a serious referee. It is a solid observational contribution with a clear methodology, and the weakness is in the interpretation of one sub-claim, not in the measurements. I'd push the authors to soften (iii), quantify the slope uncertainty, and make the group catalogue public. With those changes it's acceptable.","headline":"Solid homogeneous measurement of satellite quenching; the time-evolution claim is fragile and should be softened.","tokens_in":25400,"tokens_out":1959,"would_cite":true,"duration_ms":18655,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Satellite galaxies in DEVILS and GAMA show star-formation suppressed by ~0.5 dex relative to isolated galaxies, with suppression growing to ~1 dex in the most massive halos and satellite passive fractions rising ~10-15% over the last ~5…","keywords":["satellite quenching","galaxy evolution","DEVILS survey","GAMA survey","passive fraction","star-forming main sequence","dark matter halo mass","intermediate redshift"],"falsifier":"Measure dark matter halo masses for the same DEVILS groups with an independent mass tracer, such as X-ray emission, the Sunyaev-Zel'dovich effect, or weak lensing, and compare them to the M_halo ~ A R50 $sigma^{2}$ proxy as a function of redshift; if the proxy bias changes between z~0 and z~0.5, the apparent growth of satellite suppression could be a selection artifact rather than an evolutionary trend.","tokens_in":24284,"feed_emoji":"🌌","tokens_out":5275,"duration_ms":54213,"temperature":0.7,"pith_summary":"This paper argues that the environmental shutdown of star formation in satellite galaxies has been operating continuously over the past five billion years, not just in the local universe. Matching the high-completeness DEVILS survey at intermediate redshift (0.3<z<0.5) to the GAMA survey at low redshift (z<0.2), with galaxy and environment measurements made identically in both, the authors find that satellites have star-formation rates about 0.5 dex below isolated galaxies of the same stellar mass. In the most massive dark matter halos the suppression reaches roughly 1 dex, and at fixed stellar and halo mass the satellite passive fraction rises by about 10-15 percent from z~0.5 to today. If correct, this establishes that satellite quenching is a gradual, ongoing process whose strength scales with halo mass, and provides a directly comparable evolutionary baseline that both simulations and future surveys can be checked against.","feed_headline":"Satellite galaxies quench star formation for 5 billion years","feed_subtitle":"Matched DEVILS and GAMA data show suppression grows with halo mass, hitting ~1 dex in the most massive halos.","key_machinery":"The argument rests on three matched tools. First, friends-of-friends group finding applied identically to DEVILS and GAMA, with halo masses estimated from the scaled proxy $M_{\\rm halo}\\sim A\\,R_{50}\\,\\sigma^2$, where $R_{50}$ is the radius containing half the group members, $\\sigma$ the galaxy velocity dispersion, and $A$ a multiplicity- and redshift-dependent scaling; only groups with N>2 are used to constrain halo masses. Second, galaxy stellar masses and star-formation rates from ProSpect SED fitting with an AGN component, run in the same way for both surveys across >20 UV-FIR bands. Third, passive galaxies defined as lying >2$\\sigma$ below the star-forming main sequence, where $\\sigma$ is derived from a two-component Gaussian mixture model at each epoch. These are the load-bearing pieces that make the cross-epoch comparison possible.","core_discovery":"The central claim is that satellite galaxies have systematically suppressed star formation relative to isolated centrals at the same stellar mass, that this suppression grows with dark matter halo mass, and that at fixed stellar and halo mass the suppression becomes stronger as the universe ages. Quantitatively: a ~0.5 dex offset in log10(SFR/Msun/yr) for all satellites, rising to ~1 dex in halos with log10(Mhalo/Msun) between 14 and 15, with the offset evolving by ~0.3 dex toward the present epoch. Correspondingly, the fraction of passive satellites at 10<log10(M*/Msun)<11 increases by ~10-15% over the last ~5 Gyr, whereas isolated centrals show flat or declining passive fractions. The paper presents these as the first results from comparing DEVILS and GAMA with identical galaxy property and environment pipelines, consistent with prior observations and numerical simulations.","pith_inferences":["Extending the same matched-pipeline comparison to the other DEVILS fields, once their group catalogues are ready, would test whether the D10 result is representative of the broader intermediate-redshift population.","If the redshift-dependent suppression is real, the halo mass dependence implies that satellites in more massive halos either quench faster after infall or were accreted earlier; distinguishing those needs infall-time information, e.g., from galaxy-galaxy lensing or merger trees.","The method of comparing satellite-to-central passive fractions, rather than absolute passive fractions, could be applied to higher-redshift surveys to build a single continuous quenching timeline from z~0 to z~1.","A direct prediction follows: at fixed stellar mass, satellites in 14<log10(Mhalo)<15 halos should show progressively older star-formation histories than those in 13-14 halos, testable with spectral indices or Dn4000 strengths."],"forward_implications":["Satellite quenching has been acting continuously for the last ~5 Gyr, so models must reproduce a suppression that persists rather than an event confined to the local universe.","The ~0.3 dex growth in the satellite-isolated SFR offset toward today means the rate of environmental quenching, not just its accumulated effect, is measurable.","Because suppression is strongest in 14<log10(Mhalo/Msun)<15 halos, the most massive group and cluster environments play the dominant role in building the passive satellite population.","The observed ~10-15% rise in satellite passive fraction, against flat or declining central fractions, gives a direct target for simulations; the paper finds TNG100 and Shark match best, while SIMBA over-quenches and EAGLE under-quenches."],"supporting_citations":[{"why":"Supplies the friends-of-friends group finder and the M_halo ~ A R50 sigma^2 mass proxy that both surveys use; DEVILS applies the same algorithm and scaling.","marker":"Robotham et al. 2011"},{"why":"Prior GAMA satellite quenching analysis that this work explicitly recalculates to match halo and stellar mass ranges; supplies the low-redshift comparison points.","marker":"Davies et al. 2019b"},{"why":"Describes the ProSpect SED-fitting prescription for DEVILS stellar masses and SFRs used here.","marker":"Thorne et al. 2021"},{"why":"Provides the analogous ProSpect fitting for GAMA, run identically with an AGN model.","marker":"Bellstedt et al. 2020b"},{"why":"The shark semi-analytic model and its mock galaxy light cones used to calibrate and test the DEVILS group finder and halo mass corrections.","marker":"Lagos et al. 2018"},{"why":"Earlier probabilistic halo-mass estimate for satellite quenching at higher redshift, which this paper compares against its passive-fraction evolution.","marker":"Fossati et al. 2017"},{"why":"The canonical satellite quenching model from SDSS that sets the expected time dependence and provides satellite-to-central passive fraction comparison.","marker":"Wetzel et al. 2013"}],"fun_headline_variants":["Satellite quenching grows with halo mass over 5 Gyr","Environments stifle star formation in satellites","Heavy halos quench satellites hardest","Satellites' star formation fades with time and mass","DEVILS reveals satellite quenching's long reach"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The analysis assumes the DEVILS group catalogue, still in preparation, recovers true dark matter halos and satellite/central assignments with the same fidelity as the GAMA G3C catalogue, so that any change in the satellite passive fraction with redshift reflects real galaxy evolution rather than a drift in group purity or halo mass calibration.","fun_headline_variants_meta":{"raw":{"variants":["Satellite quenching grows with halo mass over 5 Gyr","Environments stifle star formation in satellites","Heavy halos quench satellites hardest","Satellites' star formation fades with time and mass","DEVILS reveals satellite quenching's long reach"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000148,"raw_usage":{"total_tokens":1263,"prompt_tokens":1090,"completion_tokens":173,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":706,"completion_tokens_details":{"reasoning_tokens":98}},"tokens_in":706,"tokens_out":173,"duration_ms":2978,"temperature":1.0,"reasoning_tokens":98,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T13:13:26.741703+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Measure dark matter halo masses for the same DEVILS groups with an independent mass tracer, such as X-ray emission, the Sunyaev-Zel'dovich effect, or weak lensing, and compare them to the M_halo ~ A R50 $sigma^{2}$ proxy as a function of redshift; if the proxy bias changes between z~0 and z~0.5, the apparent growth of satellite suppression could be a selection artifact rather than an evolutionary trend.","supporting_citations":[],"review_version":1}