The Galactic Disk North-south Asymmetry in Metallicity May Be A New Tracer for the Disk Warp

Biwei Jiang; Han Shen; Weixiang Sun; Xiaowei Liu

REVIEW 3 major objections 6 minor 47 references

The Galactic Disk North-south Asymmetry in Metallicity May Be A New Tracer for the Disk Warp

T0 review · 3 major / 6 minor · reviewed 2026-08-11 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read The north-south asymmetry in the Milky Way's stellar metallicity follows the same warped surface traced by Cepheids, so chemical abundance maps can serve as a new tracer of the Galactic disk warp.

desk verdict Real novelty in fitting the [Fe/H] mid-plane as a warp tracer, but the peak-equals-midplane assumption is asserted, not tested, so the parameters are provisional. read the letter →

arxiv 2412.12876 v1 pith:MSRRJR3O submitted 2024-12-17 astro-ph.GA

Weixiang Sun , Han Shen , Biwei Jiang , Xiaowei Liu This is my paper · ORCID

classification astro-ph.GA

keywords GalacticdiskwarpmetallicitydistributionredclumpstarslineofnodeLAMOSTAPOGEEstellarchemistry

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

Using more than 170,000 red clump stars from the LAMOST and APOGEE surveys, this paper tries to establish that the Galactic disk's north-south asymmetry in iron abundance ([Fe/H]) is a chemical signature of the disk warp. The authors define the metallicity mid-plane in each radius bin as the height where [Fe/H] is highest, and show that this surface is warped in the same quadratic-in-radius, sinusoidal-in-azimuth pattern as the warp traced by Cepheids. The best-fit warp for the full sample is $Z_w = 0.017\,(R-7.112)^2\sin(\phi-9.218)$ kiloparsecs, and the thin-disk subsample gives $Z_w = 0.016\,(R-6.507)^2\sin(\phi-4.240)$. If the identification holds, abundance surveys alone could measure the warp's amplitude, onset radius, and line of node without assuming a kinematic model or correcting a star-count selection function.

What carries the argument

The load-bearing object is the metallicity mid-plane, defined bin by bin as the height $Z$ where the [Fe/H] distribution peaks at a given Galactocentric radius $R$ and azimuth $\phi$. This surface is fitted with the quadratic warp model $Z_w = A_w (R - R_w)^2 \sin(\phi - \phi_0)$, where $A_w$ is the warp amplitude, $R_w$ the onset radius, and $\phi_0$ the line of node; the fit is done with a Markov Chain Monte Carlo sampler. The argument works because chemo-dynamical studies show metal-rich stars concentrate at the disk mid-plane, so the metal-rich ridge in the $R$-$Z$ plane should bend where the stellar disk bends.

What would settle it

Compare the metallicity-derived mid-plane, in the same $R$ and $\phi$ bins, with an independent geometric tracer of the warp such as the three-dimensional positions of Cepheids or a star-count map; if the [Fe/H] peak height deviates systematically from the Cepheid mid-plane toward fainter or more extinguished sightlines, the assumption fails. A simpler check is to recompute $Z_m$ separately from the LAMOST-only and APOGEE-only subsamples and see whether the two agree.

Watch

Extended reading notes

Core claim

The central claim is that the height $Z_m$ at which [Fe/H] is maximal in each radial bin traces the structural mid-plane of the warped Galactic disk. Fitting this surface with the standard warp model $Z_w = A_w (R-R_w)^2 \sin(\phi-\phi_0)$, the paper finds $A_w=0.017$, $R_w=7.112$ kpc, and $\phi_0=9.218^\circ$ for the whole red clump sample, and $A_w=0.016$, $R_w=6.507$ kpc, $\phi_0=4.240^\circ$ for the thin disk. These parameters match the warp measured independently with Cepheids, both in onset radius and in line-of-node orientation. The paper concludes that the disk's north-south metallicity asymmetry is a new chemistry-based tracer of the warp, one that avoids the need to assume a kinematic model and the need to de-project a density map against extinction and selection effects.

Load-bearing premise

The whole method rests on assuming that the height where iron abundance peaks equals the true mid-plane of the warped stellar disk, rather than being shifted by extinction, survey selection, or an asymmetric chemical distribution.

Editorial extensions

If this is right

Chemical abundance maps can be used as a standalone tracer of the Galactic warp, without constructing a kinematic model of the disk.
The line of node of the warp is not aligned with the Sun-Galactic Center direction: about $9.2^\circ$ for the whole red clump sample and $4.2^\circ$ for the thin disk, consistent with Cepheid-based values.
The warp onset radius is constrained to roughly $6.5$–$7.1$ kpc and the maximum warp amplitude is about $0.8$ kpc at $R \sim 13$–$14$ kpc, matching young-star tracers.
The thin-disk subsample gives cleaner warp parameters than the full sample, implying that thick-disk contamination biases metallicity-based warp measurements and should be removed.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

If the metallicity mid-plane tracks the warp, then large spectroscopic surveys could map the three-dimensional warp over a much larger volume than Cepheids, because red clump stars are far more numerous.
The offset between the full-sample line of node ($9.2^\circ$) and the thin-disk line of node ($4.2^\circ$) may itself trace how the line of node twists with radius or stellar age; splitting the sample into mono-age or mono-[$\alpha$/Fe] bins could test this.
The same abundance-ridge technique could be applied to resolved stellar populations in external edge-on galaxies to measure their warps from chemical maps alone.
A simulation test is available: run a warped-disk chemical evolution model and check whether the [Fe/H]-maximum surface actually coincides with the stellar mid-plane, or whether radial migration shifts it.

Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

Quick take: this paper's real novelty is fitting a warp model to the metallicity mid-plane, not just reporting the north-south asymmetry. That is worth a referee's time. The fitted LON (~9 deg for the whole RC sample, ~4 deg for the thin disk) lands close to Cepheid-based values, and the morphological agreement in Figures 5-6 is visually convincing.

What it does well: the sample is large and public (171k RC stars from APOGEE+LAMOST), the method is simple and reproducible, and the limitations paragraph is unusually honest about extinction and selection function. The authors also handle the Cepheid LON comparison sensibly, noting that Cepheid LON varies with radius and comparing against a range rather than a single number.

The soft spots are real but not fatal to the central morphological claim. The load-bearing assumption is that the Z where [Fe/H] peaks coincides with the true structural mid-plane. The paper justifies it by reference to prior chemo-dynamic results, but never validates it in this sample. With a survey like LAMOST/APOGEE, whose selection function is strongly inhomogeneous in Z and line-of-sight, that leap needs more support. The Zm points in Figures 5 and 6 have no error bars, and the MCMC uncertainties are conditional on the model, so systematic shifts are not captured. The agreement with Cepheid warp parameters is qualitative; there is no quantitative test of whether the two surfaces are consistent beyond overlapping parameters. And the abstract's 'accurately described' oversells a fit to a mid-plane whose definition is an approximation.

I do not think the core result is wrong. The [Fe/H] mid-plane does appear warped, and the similarity to the Cepheid warp is suggestive. But the difference between 'may be a new tracer' and 'is a new tracer' depends on showing that the metallicity peak tracks the stellar mid-plane even under the survey's selection. That validation should be the main referee request.

Bottom line: send it to review. It is a legitimate, testable new observable, and the authors have done the honest thing by flagging their own limitations. I would not build on the fitted parameters yet, but I would cite it as evidence that chemistry can trace the warp.

Referee Report

3 major / 6 minor

Summary. The paper proposes that the height of the metallicity mid-plane of the Milky Way disk, defined as the Z coordinate at which [Fe/H] is maximum in each radial bin, traces the Galactic warp. Using 170,729 red clump stars selected from LAMOST and APOGEE, the authors measure the [Fe/H] mid-plane as a function of Galactocentric radius R and azimuth phi for the whole sample and for the thin-disk subsample. They fit these points with the standard warp model of Eq. (1), obtaining Zw = 0.017 (R - 7.112)^2 sin(phi - 9.218) for the whole RC sample and Zw = 0.016 (R - 6.507)^2 sin(phi - 4.240) for the thin disk. They compare these parameters with Cepheid-based warp measurements and conclude that the north-south asymmetry in [Fe/H] may serve as a new tracer of the Galactic warp, with a line-of-node at about 4.24 degrees for the thin disk.

Significance. If the identification of the [Fe/H] peak with the structural mid-plane is valid, this would be the first chemical tracer of the Galactic warp, offering a complementary probe that avoids kinematic modeling assumptions and some selection corrections needed for density tracers. The paper provides explicit parameter estimates with MCMC uncertainties, compares with independent Cepheid results, and discusses caveats about selection functions and the line-of-node radial dependence. The novelty is genuine: using metallicity as a warp tracer is not established in the literature. However, the central claim rests on an assumption that is asserted with supporting citations but not tested against an independent mid-plane measurement in the same data. The significance is therefore conditional on a validation that the paper does not currently provide.

major comments (3)

[Section 3, Fig. 5 and Fig. 6] The central identification of the [Fe/H] maximum with the structural mid-plane of the warped disk is load-bearing but asserted rather than demonstrated. The paper states that 'at each R, metal-rich stars tend to be distributed at the mid-plane of the Galactic disk' and therefore 'we approximate the plane defined by metal-rich stars as the mid-plane of the stellar disk,' citing Schönrich & McMillan (2017) and Sun et al. (2024b). If selection effects, extinction, or an asymmetric vertical metallicity gradient shift the [Fe/H] peak away from the true mid-plane, then all fitted parameters of Eq. (1) inherit a systematic offset. The paper's own limitations paragraph concedes that the LAMOST/APOGEE selection function is 'very inhomogeneous' and is not modeled, which makes this concern concrete rather than hypothetical. I request a quantitative test of this mapping, for example a comparison of the derived Zm(R, phi) with a stellar-density-based mid-plane from the same sample, or a forward model of the selection function showing that the [Fe/H] peak remains unbiased.
[Figs. 5-6 and MCMC fitting] The data points used in the warp fits (black dots in Fig. 5, red dots in Fig. 6) are plotted without error bars, and the MCMC likelihood is defined as a least-squares fit with no explicit per-point uncertainties. The quoted 1-sigma intervals from the corner plots therefore reflect only the formal posterior width under an implicit noise model; they cannot capture bin-to-bin systematic errors from small counts, contamination, or bin-size choices. Please provide per-point uncertainties, for instance from bootstrap resampling or from the width of the [Fe/H]-Z profile fits, and propagate them into the likelihood when fitting Eq. (1).
[Section 3, Eq. (1) and Fig. 1] The azimuthal coverage of the sample is narrow (phi approximately -20 to 40 degrees, with fits over phi bins from -10 to 40 degrees), and the warp model of Eq. (1) assumes a straight line-of-node. Within this limited phi range, sin(phi - phi0) is only weakly varying and monotonic, so the constraint on phi0 is strongly influenced by the assumed functional form. The agreement with Cepheid LON values is encouraging, but I would like to see a sensitivity test in which the fit is repeated with phi0 fixed to a grid of plausible values and the resulting change in chi-square or evidence is reported, to quantify how strongly the LON is actually constrained by this dataset rather than by the model prior.

minor comments (6)

[Title page] There are typographical issues: 'SUBMITTED TO APJL; A CCEPTED DECEMBER 17, 2024' should read 'ACCEPTED,' and 'conman targets' should be 'common targets' in Section 2.
[Section 2] The notation for the vertical velocity is inconsistent: 'Vz' appears in Section 2 while the introduction uses 'VZ.' Please unify.
[Fig. 3 caption] The right panel defines Delta[Fe/H] as remaining metallicity, but the construction (subtracting the average [Fe/H] at each radius) is only given in the text. Please add a brief explanation in the caption for self-containedness.
[Section 3, method paragraph] The phrase 'we use the method of Fig. 3 to measure the [Fe/H] and Delta[Fe/H] distributions' is vague. Specify explicitly the binning scheme, the profile-fitting procedure, and the criterion for identifying the [Fe/H] maximum.
[Section 3, warp amplitude comparison] The statement that the amplitude is 'in perfect agreement' with Cepheid-based values is too strong given that the plotted points carry no error bars. Please provide a quantitative comparison (e.g., amplitude at a common radius, with uncertainties) and temper the wording accordingly.
[Eq. (1) and quoted parameters] The fitted values, such as Zw = 0.017 (R - 7.112)^2 sin(phi - 9.218), omit units for the amplitude Aw. Please specify that Aw is in kpc^-1 (or equivalent) so that the parametrization is reproducible.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the metallicity mid-plane fit is compared against independent Cepheid warp measurements, and no fitted parameter is renamed as a prediction.

full rationale

The derivation chain is: build a red-clump sample (Sun et al. 2024b), measure the vertical metallicity profile, define the metallicity mid-plane as the height where [Fe/H] is maximal, fit the standard warp functional form of Eq. (1), and compare the resulting Zw, Rw, and phi0 with independent Cepheid-based warp measurements. The fitted parameters come exclusively from LAMOST/APOGEE [Fe/H] data; the comparison values (Chen et al. 2019; Huang et al. 2024; Dehnen et al. 2023; Poggio et al. 2024) are external measurements and are not inputs to the fit. No equation in the paper reduces to its own input: the Zm data points are not constructed from Cepheid parameters, and Eq. (1) is a standard parametric description of the data, not a prediction derived from the Cepheid warp. The load-bearing physical assumption that the metal-rich peak marks the stellar mid-plane is asserted from prior chemo-dynamic results (Schönrich & McMillan 2017; Sun et al. 2024b) and is a physical approximation, not a definitional identity with the warp claim. Sun et al. (2024b) is self-cited for the sample and for the chemo-dynamic prior, but the latter is also supported by an external reference and is not a uniqueness theorem or an ansatz smuggled in by citation. The paper explicitly acknowledges that extinction and the inhomogeneous LAMOST/APOGEE selection function limit the inferred warp shape, which is a correctness caveat rather than evidence of circularity. Overall, the central claim has independent external content, and only incidental self-citations are present.

Assumptions & free parameters 6 free parameters · 6 assumptions · 0 invented entities

The central claim rests on six fitted warp parameters and several domain assumptions about RC distances, disk decomposition, and the interpretation of the [Fe/H] peak as the mid-plane. No new physical entities are introduced.

free parameters (6)

Aw, whole sample = 0.017
Amplitude coefficient fitted to the measured [Fe/H] mid-plane heights via MCMC; central to the warp fit.
Rw, whole sample = 7.112 kpc
Onset radius of the warp, fitted; the result depends on this value.
phi0, whole sample = 9.218 deg
Line of node fitted; compared to Cepheid values.
Aw, thin disk = 0.016
Amplitude coefficient for the thin disk fit.
Rw, thin disk = 6.507 kpc
Onset radius for the thin disk fit.
phi0, thin disk = 4.240 deg
Line of node for the thin disk fit; a headline result.

assumptions (6)

domain assumption The Z at which [Fe/H] is maximum marks the disk mid-plane.
Section 3: 'we approximate the plane defined by metal-rich stars as the mid-plane of the stellar disk'. This is the core mapping between chemistry and structure.
domain assumption The warp model Zw = Aw (R - Rw)^2 sin(phi - phi0) for R > Rw, and 0 otherwise, describes the metallicity mid-plane.
Adopted from Drimmel & Spergel (2001) and used for all fits; the shape is assumed, not derived.
domain assumption Red clump star distances are accurate to 5-10%.
Section 2: distance accuracy based on the standard-candle nature of RC stars; the inferred positions depend on this.
domain assumption Thin and thick disk separation by [Fe/H]-[alpha/Fe] cuts is clean.
Section 2: two empirical cuts separate the disks; contamination would bias the thin disk fit.
domain assumption Regions perturbed by Sagittarius can be excluded without biasing the warp fit.
Section 3: data points in Sagittarius-affected areas are excluded (citing Sun et al. 2024c), but the exact regions are not specified in this paper.
domain assumption For the visual comparison with COBE/DIRBE, sin(phi) can be set to 1.
Section 3: justified because most outer-disk stars lie near the anti-center direction; affects only the red-line overlay.

how reviews work

0 comments

Cite this review

Pith. "Pith review of The Galactic Disk North-south Asymmetry in Metallicity May Be A New Tracer for the Disk Warp." pith.science (2026). https://pith.science/paper/MSRRJR3O

@misc{pith2026241212876,
  author       = {Pith},
  title        = {Pith review of: The Galactic Disk North-south Asymmetry in Metallicity May Be A New Tracer for the Disk Warp},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/MSRRJR3O}},
  note         = {Machine review of arXiv:2412.12876}
}

abstract

Galactic disk warp has been widely characterized by stellar distributions and stellar kinematics but has not been traced by stellar chemistry. Here, we use a sample with over 170,000 red clump (RC) stars selected from LAMOST and APOGEE first to establish a correlation between the north-south asymmetry in metallicity ([Fe/H]) and the disk warp. Our results indicate that the height of the [Fe/H] mid-plane for the whole RC sample stars is accurately described as $Z_{w}$ = 0.017 ($R$ $-$ 7.112)$^{2}$ sin($\phi$ $-$ 9.218). This morphology aligns closely with the warp traced by Cepheids, suggesting that the disk north-south asymmetry in [Fe/H] may serve as a new tracer for the Galactic warp. Our detailed analysis of the young/thin disk stars of this RC sample suggests that its warp is well-modeled as $Z_{w}$ = 0.016 ($R$ $-$ 6.507)$^{2}$ sin($\phi$ $-$ 4.240), indicating that the line of node (LON) of the Galactic warp is oriented at 4.240$_{-1.747}^{+1.641}$ degree.

Figures

Figures reproduced from arXiv: 2412.12876 by the authors.

**Figure 1.** Left panel: Spatial distribution of the LAMOST RC sample stars, in the R–Z plane, color-coded by stellar number densities. There are no less than two stars in a bin, with both axes spaced by 0.1 kpc. Right panel: Spatial distribution of the LAMOST RC sample stars, in the X–Y plane, with over-plotted by the ϕ angle line. There is a minimum of five stars per bin, with both axes spaced by 0.25 kpc. The RC sample stars … view at source ↗

**Figure 2.** Distribution of the RC sample stars, in the [Fe/H]−[α/Fe] plane, over-plotted with contours of equal densities. The number densities are represented by the colorbar on the right. The horizontal axis and vertical axis are respectively spaced by 0.025 dex and 0.02 dex, with no less than 20 stars in a bin. The two dashed lines separate the thin (below the lines) and the thick (above the lines) disk stars. This paper i… view at source ↗

**Figure 3.** Metallicity ([Fe/H], left panel) and remaining metallicity (∆[Fe/H], right panel) distribution, in the R - Z plane, of the whole RC sample stars [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗

Figures from the paper (3 more)

**Figure 4.** Figure 4: Metallicity distribution, in the R - Z plane, of the thin (left panel) and thick (right panel) disks. tion of R. The fact that the results (Schonrich et al. ¨ 2017; Sun et al. 2024b) of chemo-dynamics have generally revealed that at each R, metal-rich stars tend to be …

**Figure 5.** Figure 5: The disk warp is traced by the disk metallicity mid-plane, of the whole RC sample stars. The black dots represent the disk mid-plane determined by the method of the right panel of [PITH_FULL_IMAGE:figures/full_fig_p004_5.png]

**Figure 6.** Figure 6: The disk warp is traced by the disk metallicity mid-plane of the thin disk stars. The red dots represent the disk mid-plane determined by the method of the right panel of [PITH_FULL_IMAGE:figures/full_fig_p005_6.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

47 extracted references · 40 canonical work pages

[1]

B., Robin, A

Amˆores, E. B., Robin, A. C., Reyl´e, C. 2017, A&A, 602, A67

work page 2017
[2]

On the age distribution of Classical Cepheids in the Galaxy

Anders, F., Padois, C., Vilanova Sar, M., et al. 2024, arXiv:2406.06228

work page Pith review arXiv 2024
[3]

Battaner, E. e. a. 1990, A&A, 236, 1

work page 1990
[4]

S., Yong, D., Mel´endez, J., 2011, ApJL, 735, L46 Bland Hawthorn, J., Gerhard, O

Bensby, T., Alves-Brito, A., Oey, M. S., Yong, D., Mel´endez, J., 2011, ApJL, 735, L46 Bland Hawthorn, J., Gerhard, O. 2016, ARA&A, 54, 529

work page 2011
[5]

L., Rix, H

Bovy, J., Nidever, D. L., Rix, H. W., et al. 2014, ApJ, 790, 127

work page 2014
[6]

2024, MNRAS, 528, 4409

Cabrera-Gadea, M., Mateu, C., Ramos, P., et al. 2024, MNRAS, 528, 4409

work page 2024
[7]

2019, NatAs, 3, 320

Chen, X., Wang, S., Deng, L., et al. 2019, NatAs, 3, 320

work page 2019
[8]

Q., Zhao, Y

Cui, X. Q., Zhao, Y . H., Chu, Y . Q., et al. 2012, RAA, 12, 1197

work page 2012

Show all 47 references

[9]

P., Sellwood, J

Debattista, V . P., Sellwood, J. A. 1999, ApJ, 513, L107

1999
[10]

2023, MNRAS, 523, 1556

Dehnen, W., Semczuk, M., & Sch¨onrich, R. 2023, MNRAS, 523, 1556

2023
[11]

C., Newberg, H

Deng, L. C., Newberg, H. J., Liu, C., et al. 2012, RAA, 12, 735

2012
[12]

Drimmel, R., Spergel, D. N. 2001, ApJ, 556, 181

2001
[13]

W., Lang, D., et al

Foreman-Mackey, D., Hogg, D. W., Lang, D., et al. 2013, PASP, 125, 306

2013
[14]

T., Berriman, G

Freudenreich, H. T., Berriman, G. B., Dwek, E., et al. 1994, ApJL, 429, L69 Gaia Collaboration, Katz, D., Antoja, T., Romero-G´omez, M., et al. 2018, A&A, 616, A11 Gaia Collaboration, Creevey, O. L., Sarro, L. M., Lobel, A., et al. et al. 2023a, A&A, 674, A39 Gaia Collaboratio...

1994
[15]

A., Cohen, R

Grabelsky, D. A., Cohen, R. S., Bronfman, L., Thaddeus, P., & May, J. 1987, ApJ, 315, 122

1987
[16]

M., Schlafly, E., Zucker, C., et al

Green, G. M., Schlafly, E., Zucker, C., et al. 2019, ApJ, 887, 93

2019
[17]

R., Lee, Y

Han, D. R., Lee, Y . S., Kim, Y . K., et al. 2020, ApJ, 896, 14H

2020
[18]

R., Bland-Hawthorn, J., Sharma, S., et al., 2020, MNRAS, 493, 2952

Hayden, M. R., Bland-Hawthorn, J., Sharma, S., et al., 2020, MNRAS, 493, 2952

2020
[19]

W., Yuan H

Huang, Y ., Liu X. W., Yuan H. B., et al., 2015, MNRAS, 449, 162

2015
[20]

W., Yuan, H

Huang, Y ., Liu, X. W., Yuan, H. B., et al., 2016, MNRAS, 463, 2623

2016
[21]

W., et al., 2018, ApJ, 864, 129

Huang, Y ., Sch¨onrich, R., Liu, X. W., et al., 2018, ApJ, 864, 129

2018
[22]

W., et al., 2020, ApJS, 249, 29

Huang, Y ., Sch¨onrich, R., Zhang, H. W., et al., 2020, ApJS, 249, 29

2020
[23]

2024, Nature Astronomy, 8, 1294

Huang, Y ., Feng, Q., Khachaturyants, T., et al. 2024, Nature Astronomy, 8, 1294

2024
[24]

G., & Binney, J

Jiang, I. G., & Binney, J. 1999, MNRAS, 303, L7

1999
[25]

D., Woltjer, L

Kahn, F. D., Woltjer, L. 1959, ApJ, 130, 705 Kerr F. J. 1957, AJ, 62, 93

1959
[26]

2024, arXiv:2410.22036

Khanna, S., Yu, J., Drimmel, R., et al. 2024, arXiv:2410.22036

2024
[27]

H., Peirani, S., Kim, S., et al

Kim, J. H., Peirani, S., Kim, S., et al. 2014, ApJ, 789, 90

2014
[28]

L., Babusiaux, C., et al

Lallement, R., Vergely, J. L., Babusiaux, C., et al. 2022, A&A, 661, A147

2022
[29]

S., Beers, T

Lee, Y . S., Beers, T. C., An, D., et al. 2011, ApJ, 738, 187

2011
[30]

Y ., Huang, Y ., Chen, B

Li, X. Y ., Huang, Y ., Chen, B. Q., et al. 2020, ApJ, 901, 56

2020
[31]

W., Yuan, H

Liu, X. W., Yuan, H. B., Huo, Z. Y ., et al. 2014, in IAU Symp. 298, Setting the Scene for Gaia and LAMOST (Cambridge: Cambridge Univ. Press), 310 L´opez-Corredoira, M., Betancort-Rijo, J., Beckman, J. E. 2002a, A&A, 386, 169 L´opez-Corredoira, M., Cabrera-Lavers, A., Garz´on,...

2014
[32]

T., Bovy, J., Leung, H

Mackereth, J. T., Bovy, J., Leung, H. W., et al. 2019, MNRAS, 489, 176

2019
[33]

R., Schiavon, R

Majewski, S. R., Schiavon, R. P., Frinchaboy, P. M., et al. 2017, AJ, 154, 94

2017
[34]

1988, A&A, 194, 107

Miyamoto, M., Yoshizawa, M., & Suzuki, S. 1988, A&A, 194, 107

1988
[35]

2006, A&A, 451, 515

Momany, Y ., Zaggia, S., Gilmore, G., et al. 2006, A&A, 451, 515

2006
[36]

C., & Binney, J

Ostriker, E. C., & Binney, J. J. 1989, MNRAS, 237, 785

1989
[37]

L., et al

Poggio, E., Drimmel, R., Smart, R. L., et al. 2017, A&A, 601, A115

2017
[38]

G., et al

Poggio, E., Drimmel, R., Lattanzi, M. G., et al. 2018, MNRAS, 481, L21

2018
[39]

2024, arXiv:2407.18659

Poggio, E., Khanna, S., Drimmel, R., et al. 2024, arXiv:2407.18659

2024 arXiv
[40]

J., & Brunthaler, A

Reid, M. J., & Brunthaler, A. 2004, ApJ, 616, 872

2004
[41]

J., Menten, K

Reid, M. J., Menten, K. M., Brunthaler, A., et al. 2014, ApJ, 783, 130 Sch¨onrich, R., Binney, J., & Dehnen, W. 2010, MNRAS, 403, 1829 Sch¨onrich, R. 2012, MNRAS, 427, 274 Sch¨onrich, R., & McMillan, P. J. 2017, MNRAS, 467, 1154 Sch¨onrich, R., & Dehnen, W. 2018, MNRAS, 478, 3809

2014
[42]

M., Skowron, J., Mr´oz, P., et al

Skowron, D. M., Skowron, J., Mr´oz, P., et al. 2019, Science, 365, 478

2019
[43]

S., Casertano, S

Sparke, L. S., Casertano, S. 1988, MNRAS, 234, 873

1988
[44]

X., Huang, Y ., Wang, H

Sun, W. X., Huang, Y ., Wang, H. F., et al. 2020, ApJ, 903, 12

2020
[45]

X., Shen, H., Jiang, B

Sun, W. X., Shen, H., Jiang, B. W., & Liu, X. W. . 2024c, arXiv:2412.07089

arXiv
[46]

2024, MNRAS, 527, 4863

Uppal, N., Ganesh, S., & Schultheis, M. 2024, MNRAS, 527, 4863

2024
[47]

B., Liu, X

Yuan, H. B., Liu, X. W., Huo, Z. Y ., et al. 2015, MNRAS, 448, 855 Yusifov I. 2004, in Uyaniker B., Reich W., Wielebinski R., eds, The Magnetized Interstellar Medium. Copernicus GmbH, Katlenburg-Lindau, p. 165 APPENDIX A. EXAMPLE POSTERIOR DISTRIBUTIONS OF MCMC SAMPLES OF THE ...

2015

Pith tools

Reviewed August 11, 2026 · model on record in the stance chip above.

[1] [1]

B., Robin, A

Amˆores, E. B., Robin, A. C., Reyl´e, C. 2017, A&A, 602, A67

work page 2017

[2] [2]

On the age distribution of Classical Cepheids in the Galaxy

Anders, F., Padois, C., Vilanova Sar, M., et al. 2024, arXiv:2406.06228

work page Pith review arXiv 2024

[3] [3]

Battaner, E. e. a. 1990, A&A, 236, 1

work page 1990

[4] [4]

S., Yong, D., Mel´endez, J., 2011, ApJL, 735, L46 Bland Hawthorn, J., Gerhard, O

Bensby, T., Alves-Brito, A., Oey, M. S., Yong, D., Mel´endez, J., 2011, ApJL, 735, L46 Bland Hawthorn, J., Gerhard, O. 2016, ARA&A, 54, 529

work page 2011

[5] [5]

L., Rix, H

Bovy, J., Nidever, D. L., Rix, H. W., et al. 2014, ApJ, 790, 127

work page 2014

[6] [6]

2024, MNRAS, 528, 4409

Cabrera-Gadea, M., Mateu, C., Ramos, P., et al. 2024, MNRAS, 528, 4409

work page 2024

[7] [7]

2019, NatAs, 3, 320

Chen, X., Wang, S., Deng, L., et al. 2019, NatAs, 3, 320

work page 2019

[8] [8]

Q., Zhao, Y

Cui, X. Q., Zhao, Y . H., Chu, Y . Q., et al. 2012, RAA, 12, 1197

work page 2012