{"id":"a8669a86-80c5-48a5-94a6-8a659700a5b0","arxiv_id":"2505.13145","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":6,"one_line_summary":"Simulations with the maria code indicate that a large-field-of-view single-dish telescope at AtLAST can map the full solar disk in under a minute with appropriately sized detector arrays, and in seconds with arrays above 100,000 elements.","lead":"This paper simulates future solar observations with the proposed AtLAST single-dish telescope, showing that full-disk scans could be completed in under a minute with tens of thousands of detectors, and in seconds with very large arrays. The result matters because current millimeter full-disk solar maps take about ten minutes, so AtLAST could open a new window on fast solar phenomena such as flares.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Scan-time scaling relation (Eq. 4) is not self-consistent with the quoted Case B/C simulation times, so the central cadence claim rests on an unverified fit.","rationale":"The reader's weakest assumption focused on the external parameters (mount speed limits and array filling). My arithmetic check of the printed equations found a more severe internal inconsistency: applying Eq. 4 directly to the instrument parameters of Case B gives ~19 s, not the 11.4 s reported as the maria simulation result, and the difference is far beyond the claimed fit uncertainties. Since the strongest claim ('sub-minute cadence') is grounded in the scaling relations and the simulated cases, an internal contradiction in the central scaling relation means the quantitative headline is not yet settled. However, the qualitative conclusion (double-circle scans with a large filled array can beat ALMA's ~10 min cadence) is robust to this arithmetic issue: even at 19 s, Case B is still sub-minute, so the central claim survives in a weaker form. The most load-bearing uncertainty is thus not whether sub-minute cadence is conceivable, but whether the specific numbers in Figure 6 and Table 2 (and therefore the paper's quantitative forecasts) are reliable. I am recommending the same verdict as the reader (CONDITIONAL) because the concern is addressable by refitting the relations and does not invalidate the qualitative conclusion. I agree only partially with the reader's identified weakest assumption because the paper's own equations are the more immediate vulnerability; the mount velocity and array-filling assumptions are real but more clearly stated as external assumptions, whereas the Eq. 4 / Case B mismatch is an internal consistency problem that should be fixed before the numbers are cited.","tokens_in":22737,"tokens_out":2175,"duration_ms":16937,"concrete_test":"Re-derive the scan-time curves of Figure 6 directly from maria simulations rather than from the geometric fits: run the double-circle scan at FOV = 0.146679 deg with l=1.0 FOV and AtLAST velocity/acceleration limits (3 deg/s, 1 deg/s^2), and compare the resulting time to the quoted 11.4 s and to the Eq. 4 prediction of ~19 s. Then repeat at two additional FOV values spanning the range used in Figure 6 (e.g., ~0.05 deg and ~0.3 deg) at l=0.5 and l=1.0 FOV. If the simulated times agree with Eq. 3-4, the inconsistency with Case B must be explained (e.g., a different sampling length or a different definition of 'sufficient'); if they agree with the case quotes instead, then Eqs. 3-4 and all derived pixel-count/cadence tables must be refit.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim is that full-disk scans with sub-minute cadence are achievable. The quantitative backbone for that claim is the fitted scan-time relations in Sect. 4.3, especially Eq. 4 (tscan,l=1.0 = FOV^-0.897 * 10^0.504), which is used to generate Figure 6 and Table 2. However, those fitted relations are not self-consistent with the actual simulated scan times reported for the cases. Case A matches Eq. 4 reasonably (FOV=0.03051 deg gives ~83 s vs. the reported 89 s). But Eq. 4 for Case B (FOV=0.146679 deg) gives t ~ 10^0.504 * (0.146679)^-0.897 ≈ 3.19 * 5.99 ≈ 19.1 s, whereas the paper reports ~11.4 s for Case B. For Case C (FOV=0.30573 deg), Eq. 4 gives t ≈ 3.19 * 2.93 ≈ 9.35 s, whereas the reported scan is ~2.7 s. The discrepancy at Case B is nearly a factor of 1.7, and at Case C it is a factor of ~3.5; the Case C scan is not even a double-circle pattern, so it should not be compared to Eq. 4. But Case B is exactly the l=1.0 FOV double-circle case and is claimed to be summarized by these relations. If the relation was fit to geometric sampling criteria rather than to the same acceleration-limited trajectory used in the maria simulations, then the cadence values in Figure 6 and Table 2 are not anchored to the simulated cases and could be off by comparable factors. The paper states the fits are based on a 'sufficient sampling' geometric criterion (gap = FOV), while the simulations define sufficiency as recovering the input map structure after smoothing; the two criteria are not the same. Because the conclusion that 50,000-pixel instruments achieve sub-minute cadence depends on these specific numbers, and because the same fitted relation contradicts the paper's own Case B simulation quoted at 11.4 s, the scaling used for the headline result is internally inconsistent and needs verification.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper uses the maria single-dish telescope simulator to forecast full-disk solar observations with the proposed AtLAST 50-m telescope. It constructs realistic millimeter input maps by combining SDO/AIA ultraviolet images with ALMA total-power maps, simulates three representative instrument configurations (a 1,000-pixel small-FOV array, a 50,000-pixel intermediate-FOV array, and a 100,000-pixel large-FOV array), and compares double-circle and circular scan patterns. From these simulations the paper derives power-law scaling relations between instrument field of view, pixel count, and full-disk scan time, and concludes that sub-minute cadence is achievable across AtLAST's 100-950 GHz range, with cadences of a few seconds for large-FOV instruments.","tokens_in":23145,"tokens_out":6372,"duration_ms":61787,"significance":"If the results hold, this is a valuable and timely design-study contribution: it gives concrete, quantitative guidance for a possible solar instrument at AtLAST, uses a publicly available simulator, and makes falsifiable predictions about scan times and required pixel counts that can be tested once the telescope and instrument parameters are finalized. The comparison with ALMA total-power full-disk maps (about 10-minute cadence) indicates a potential order-of-magnitude improvement in cadence and a substantial gain in angular resolution. However, the quantitative relations that anchor Figure 6 and Table 2 are not self-consistent with the explicitly simulated scan times, so the headline cadence numbers are not yet presented in a fully coherent way.","major_comments":[{"comment":"The fitted scan-time relations do not reproduce the simulated scan times reported for Cases A and B. For Case B (FOV = 0.146679 deg and l = 1.0 FOV), Eq. (4) gives approximately 17.9 s, whereas the simulation in §4.2.2 reports about 11.4 s. For Case A (FOV = 0.03051 deg), Eq. (4) gives about 73 s and Eq. (3) gives about 135 s, bracketing but not matching the reported 89 s. The reason appears to be that Eqs. (1)–(4) are derived from a geometric 'no gaps' criterion with sampling length l = 1.0 FOV or l = 0.5 FOV, while the simulations declare a scan sufficient when the input map structures are recovered after smoothing. Because Figure 6 and Table 2 are generated from Eqs. (3)–(4), the central cadence numbers are not firmly anchored to the simulated trajectories. Please either refit the relations using the same sufficiency criterion as the simulations, or report the scan times from the simulated Cases A–C directly, and quantify the difference between the two criteria.","section":"§4.3, Eqs. (3)–(4)"},{"comment":"For Case B, Eq. (2) with l = 1.0 FOV predicts about 6.2 secondary circles for a region of 2400 arcsec diameter, whereas the simulation uses only four secondary circles and finds this sufficient. This is not a minor rounding difference; it corresponds to a factor of roughly 1.5 in coverage and about a factor of 1.6 in scan time. The definition of 'sufficient sampling' therefore needs to be made explicit and applied uniformly. As written, the reader cannot tell whether the quoted 11.4 s scan time corresponds to the same quality criterion as the power-law fits, and the status of Figure 6 and Table 2 as predictions is unclear.","section":"§4.2.2 and Eq. (2)"}],"minor_comments":[{"comment":"The text states that 36 minor circles were sufficient for Case A, while the label in Fig. 3a reads ncirc = 35; please reconcile these numbers.","section":"§4.2.1 and Fig. 3a"},{"comment":"The text says the trends in Fig. 6 were made with a sampling length of l = 0.5 FOV, but Fig. 6 and the surrounding discussion show both l = 0.5 FOV and l = 1.0 FOV; please clarify which sampling length was used for the entries in Table 2.","section":"§5.1 and Fig. 6"},{"comment":"The power-law fits in Eqs. (1)–(4) are quoted with parameter uncertainties, but no goodness-of-fit statistic or number of fitted FOV values is reported; please add the fit range, number of points, and scatter.","section":"§4.3"},{"comment":"The abstract states that instruments with 1,000–50,000 detectors achieve sub-minute cadence across AtLAST's frequency range, but Table 2 shows that 950 GHz with 0.5 fλ spacing requires about 97,768 pixels for a one-minute cadence; the claim should be qualified with the relevant pixel spacings.","section":"Abstract and Table 2"}],"recommendation":"major_revision","confidential_remarks":"The paper is a useful design study and the central conclusion that sub-minute full-disk cadence is plausible is probably robust, but the internal inconsistency between the analytic scaling relations and the explicitly simulated scan times should be resolved before publication. The authors should be asked to state clearly whether the cadence numbers in Fig. 6 and Table 2 are based on the geometric criterion or on the simulated scan trajectories, and to quantify the difference. No concerns about novelty or citation practice."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: useful, honest feasibility study with a real internal inconsistency in the quantitative backbone. Your stress-test arithmetic checks out: Eq. 4 predicts ~18 s for Case B while the paper quotes 11.4 s, and it is off in the other direction for Case A (~73 s vs 89 s). That mismatch is not a rounding issue; it is a factor of 1.2–1.6. Case C isn't a fair test since it uses a circular scan, not double-circle, but the Case B test alone is enough. The fits in Fig. 6 and Table 2 are the numbers people will quote, and right now they are not anchored to the simulations they summarize. The paper says the fits come from a geometric 'sufficient sampling' criterion (gap = FOV), while the maria cases define sufficiency by recovering map structure after smoothing; those are different criteria, and the mismatch shows up in the numbers.\n\nWhat is genuinely new: quantitative cadence forecasts for full-disk solar scanning with AtLAST as a function of pixel count, spacing, FOV, and scan pattern, plus a direct comparison of scan strategies and power-spectrum checks with and without an atmosphere. The maria simulator is published and independently testable, and the input maps are built from public SDO and ALMA data. That is real, reproducible work, and the heavy reliance on earlier AtLAST design papers and on the same team's simulator is not circular.\n\nThe qualitative headline is still plausible. The explicit Case B and C simulations give 11.4 s and 2.7 s full-disk scans, so \"well under a minute with a large filled focal-plane array\" is directly supported. My concern is narrower: the generalized scaling used to make predictions for intermediate detector counts does not match those self-same simulations. If the relation is refit and the numbers move, the recommendation could get better or worse; we cannot tell from the paper.\n\nMinor issues: no detector noise model, so the map-quality claims are about sampling and atmosphere only; the input maps are one-epoch scaled AIA+ALMA, which is fine for scan trade studies but not for scientific maps; and the abstract slightly oversells the 1000-detector end.\n\nWho should read it: the AtLAST instrument group and anyone planning solar or extended-source observing with a fast-scanning single dish. It deserves a serious referee. I would send it to review and ask for a reconciliation of Eq. 4 with the direct simulations, a detector-noise estimate, and a toned-down abstract.","headline":"Useful feasibility study with a real internal inconsistency: the scan-time scaling relation does not reproduce the paper's own simulated cases; the qualitative sub-minute conclusion is plausible, but the quantitative forecasts need fixing.","tokens_in":23773,"tokens_out":4834,"would_cite":true,"duration_ms":49659,"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":"The paper argues that AtLAST can scan the full solar disk in under a minute with instruments of a few thousand to 50,000 detectors, and in seconds with ~100,000-detector large-field-of-view arrays.","keywords":["AtLAST","solar observations","submillimeter astronomy","full-disk mapping","scan patterns","focal plane arrays","time cadence","solar chromosphere"],"falsifier":"Run the actual mount through the small-field double-circle pattern and the large-field circular pattern and compare the wall-clock times to the fitted $t\\propto \\mathrm{FOV}^{-0.9}$ relation; a clear mismatch would overturn the cadence claims. A simpler check is to re-run the intermediate simulation with the same sampling-length criterion used for the fits and see whether the full disk stays covered without gaps.","tokens_in":22506,"feed_emoji":"☀️","tokens_out":12599,"duration_ms":119156,"temperature":0.7,"pith_summary":"This paper simulates full-disk solar observations with the planned 50-metre Atacama Large Aperture Submillimeter Telescope (AtLAST) to find out how fast the whole Sun can be mapped. It establishes that first-generation instruments with 1,000 to 50,000 detector elements can scan the full disk in under a minute, and that a ~100,000-element array with a large field of view can do it in a few seconds using a simple circular scan. If these simulations are right, millimetre astronomy could move from ALMA's ~10-minute total-power full-disk maps to sub-minute or second-level movies of the solar chromosphere. That would open a new window on short-lived events such as flares, which are currently very hard to catch with ALMA's small field of view.","feed_headline":"Simulations: whole-Sun scans in under a minute","feed_subtitle":"With thousands of detectors, the planned AtLAST telescope could catch flares and chromosphere dynamics as they unfold.","key_machinery":"The engine of the argument is the combination of three design choices: the instantaneous field of view of the focal-plane array (set by pixel count, pixel spacing in units of the wavelength-scaled beam, and observing frequency), the scan pattern (double-circle vs. simple circle), and the sampling length $l$ — the gap between adjacent scan paths, normalized to the field of view. For the double-circle pattern the paper derives power-law fits $N_{\\mathrm{circles}}\\propto \\mathrm{FOV}^{-0.95}$ and $t_{\\mathrm{scan}}\\propto \\mathrm{FOV}^{-0.9}$ for $l=0.5$ and $1.0\\,\\mathrm{FOV}$, which convert instrumental parameters into predicted full-disk cadence. The maria code supplies the realistic time-ordered data that let the authors test whether the resulting maps actually recover the input Sun.","core_discovery":"The paper's central claim is that full-disk millimetre imaging of the Sun is within reach of the planned AtLAST telescope at cadences no current solar millimetre facility provides. Using the maria simulator with realistic all-disk input maps built from SDO ultraviolet and ALMA total-power data, it simulates three instrument archetypes: a small-field-of-view array (1,000 detectors, $2f\\lambda$ spacing, 0.03051° field of view) completes a dense 36-circle double-circle scan in 89 seconds; an intermediate array (50,000 detectors, $1f\\lambda$ spacing, 0.146679° field of view) covers the disk in about 11.4 seconds with a 4-circle double-circle scan; and a large-field-of-view array (100,000 detectors, $2f\\lambda$ spacing, 0.30573° field of view) uses a simple circular scan of radius $0.6\\,R_\\odot$ and finishes in about 2.7 seconds. Power-law fits to these simulations give the number of secondary circles and the scan time as functions of instrument field of view, so any detector count, spacing, and frequency can be translated into a full-disk cadence. The conclusion is that a realistic first-generation multi-chroic camera reaches sub-minute cadence across the 100–950 GHz range, with the double-circle pattern used at ALMA remaining acceptable for small and intermediate fields of view while a plain circle wins at large fields of view.","pith_inferences":["A natural extension is to run the same simulations with a time-dependent input map, since the paper uses a static Sun; a flaring brightening that evolves during the ~3-second Case C circle would tell how much transient information is blurred.","The cadence-vs-FOV scaling (roughly $t\\propto \\mathrm{FOV}^{-0.9}$) should transfer to other extended millimetre targets of similar angular size, so the results could inform scanning strategies for observations beyond the Sun.","The paper's pixel-count tables (for example, ~97,000 pixels at $0.5f\\lambda$ spacing for a 1-minute cadence at 950 GHz) give instrument designers a concrete trade-off between Nyquist sampling, detector count, and cadence; optimizing that trade-off is the immediate engineering follow-up."],"forward_implications":["With a first-generation array of 50,000 detectors per band, full-disk maps at all considered bands can be made in under a minute, roughly ten times faster than ALMA's total-power scans and at about four times the angular resolution.","Pushing to ~100,000 detectors with a field of view of at least about one solar radius brings full-disk cadence to a few seconds, enough to resolve the ~5-minute peak of a small flare with dozens to over a hundred time steps.","The double-circle scan pattern currently used at ALMA is adequate for AtLAST at small to intermediate fields of view; at larger fields of view a simple circular scan is more efficient, so the optimal scan strategy depends on the instrument built.","Atmospheric transmission limits high-frequency (670 and 950 GHz) work more than low-frequency work, and a large-field-of-view fast scan preserves smaller spatial scales than a small-field-of-view slow scan at the same frequency.","A high-cadence full-disk millimetre capability would complement ALMA by catching transient events such as flares and by mapping large-scale structures like prominences that exceed ALMA's field of view."],"supporting_citations":[{"why":"Supplies the telescope technical requirements (aperture, velocity and acceleration limits, field of view) assumed in every scan-time calculation.","marker":"Mroczkowski et al. 2025"},{"why":"Defines the double-circle scan pattern, the sampling-length concept, and the 2400-arcsecond full-disk region, and provides the ~10-minute ALMA total-power cadence used as the baseline.","marker":"White et al. 2017"},{"why":"Presents the maria simulator used to produce the synthetic solar observations and to compare scan patterns.","marker":"van Marrewijk et al. 2024"},{"why":"Provides the atmosphere model based on Chajnantor weather data used for the with-atmosphere simulations.","marker":"Morris et al. 2022"},{"why":"Gives the first- and second-generation pixel-count estimates (50,000 and 300,000 per band) that define the realistic instrument range.","marker":"van Kampen 2024"},{"why":"Sets the solar science cases and the corresponding cadence and field-of-view constraints that motivate the scan-time targets.","marker":"Wedemeyer et al. 2024"},{"why":"Reports an ALMA-observed microflare with a ~5-minute peak, used to judge how well the predicted cadences sample flare evolution.","marker":"Shimizu et al. 2021"},{"why":"Supplies the SDO AIA 304 and 1600 Å full-disk maps used as the basis for constructing the millimetre input maps.","marker":"Lemen et al. 2012"},{"why":"Provides the wavelength-to-brightness-temperature relation used to scale the input maps to realistic millimetre temperatures.","marker":"Loukitcheva et al. 2004"}],"fun_headline_variants":["Simulations: AtLAST full-disk solar scans in under 1 minute","AtLAST could scan entire Sun in under a minute","Sub-minute full-disk solar imaging forecast for AtLAST","Whole-Sun millimeter scans in <1 minute with AtLAST","Forecast: AtLAST achieves rapid full-disk solar mapping"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"Everything rests on the assumption that AtLAST's mount can actually sustain 3 degrees per second and 1 degree per second squared while a detector array densely fills its nominal field of view; if the real telescope slews slower or the array has gaps, the quoted scan times are too short.","fun_headline_variants_meta":{"raw":{"variants":["Simulations: AtLAST full-disk solar scans in under 1 minute","AtLAST could scan entire Sun in under a minute","Sub-minute full-disk solar imaging forecast for AtLAST","Whole-Sun millimeter scans in <1 minute with AtLAST","Forecast: AtLAST achieves rapid full-disk solar mapping"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000272,"raw_usage":{"total_tokens":1776,"prompt_tokens":1235,"completion_tokens":541,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":851,"completion_tokens_details":{"reasoning_tokens":455}},"tokens_in":851,"tokens_out":541,"duration_ms":5696,"temperature":1.0,"reasoning_tokens":455,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-15T20:19:31.881268+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Run the actual mount through the small-field double-circle pattern and the large-field circular pattern and compare the wall-clock times to the fitted $t\\propto \\mathrm{FOV}^{-0.9}$ relation; a clear mismatch would overturn the cadence claims. A simpler check is to re-run the intermediate simulation with the same sampling-length criterion used for the fits and see whether the full disk stays covered without gaps.","supporting_citations":[],"review_version":1}