pith. machine review for the scientific record. sign in

arxiv: 2604.23963 · v1 · submitted 2026-04-27 · 🌌 astro-ph.GA

Recognition: unknown

East Asian VLBI Network astrometry toward the star-forming region G040.96+02.48 in the Extreme Outer Galaxy

Xianjin Shen , Zehao Lin , Nobuyuki Sakai , Ye Xu , Shuaibo Bian , Yuanwei Wu , Yan Sun , Dejian Liu
show 13 more authors
Jingjing Li Bo Zhang Shuangjing Xu Tomoaki Oyama Chungsik Oh Wu Jiang Lang Cui Pengfei Jiang Guanghui Li Mareki Honma Se-Jin Oh Zhi-Qiang Shen Na Wang
Authors on Pith no claims yet

Pith reviewed 2026-05-08 03:02 UTC · model grok-4.3

classification 🌌 astro-ph.GA
keywords VLBI astrometrywater maserstar-forming regionGalactic warpkinematic distanceOuter Scutum-Centaurus ArmExtreme Outer Galaxy
0
0 comments X

The pith

VLBI astrometry of a water maser places G040.96+02.48 at 20.2 kpc, outside the Outer Scutum-Centaurus Arm in a warped outer disk.

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

The paper uses East Asian VLBI Network observations of a 22 GHz water maser to measure the proper motion of star-forming region G040.96+02.48 on the far side of the Milky Way. Combining these motions with radial velocity yields a three-dimensional kinematic distance of 20.2 kpc. This location sits slightly beyond the Outer Scutum-Centaurus Arm. The derived vertical height of 872 pc matches expectations from a precessing warp model for the outer Galactic disk. The measurements also show peculiar motions including a large outward radial velocity component.

Core claim

The water maser's proper motion is measured as (μ_α cos δ, μ_δ) = (-2.06, -2.95) mas yr^{-1}. The resulting kinematic distance to G040.96+02.48 is 20.2 ± 3.2 kpc, placing the region slightly outside the Outer Scutum-Centaurus Arm. The corresponding vertical height of 872 ± 139 pc indicates a significant warp of the outer Galactic disk in agreement with the latest precessing warp model. Peculiar motions include a large outward radial velocity of -32 ± 18 km s^{-1}.

What carries the argument

Three-dimensional kinematic distance calculated from VLBI-measured proper motions of the associated water maser together with the region's radial velocity under a standard Galactic rotation curve.

Load-bearing premise

The maser shares the exact distance of the star-forming region and the region follows circular orbits in the standard Galactic rotation curve without significant streaming or non-circular motions.

What would settle it

An independent trigonometric parallax or other direct distance measurement that differs from 20.2 kpc by more than the stated uncertainty would falsify the kinematic distance and warp height.

Figures

Figures reproduced from arXiv: 2604.23963 by Bo Zhang, Chungsik Oh, Dejian Liu, Guanghui Li, Jingjing Li, Lang Cui, Mareki Honma, Na Wang, Nobuyuki Sakai, Pengfei Jiang, Se-Jin Oh, Shuaibo Bian, Shuangjing Xu, Tomoaki Oyama, Wu Jiang, Xianjin Shen, Yan Sun, Ye Xu, Yuanwei Wu, Zehao Lin, Zhi-Qiang Shen.

Figure 1
Figure 1. Figure 1: Parallax fitting results without incorporating geodetic blocks. The top panels present the eastward (left) and northward (right) positional offsets as a function of time. Similar to the top panels, the bottom panels show the eastward and northward offsets with the fitted proper motion removed. Outliers are marked by orange scatters view at source ↗
Figure 2
Figure 2. Figure 2 view at source ↗
Figure 4
Figure 4. Figure 4: Distance PDFs for star-forming region G040.96+02.48. The term ”kinematic” denotes the PDF de￾rived solely from the LSR velocity. Abbreviations for the proper motions in Galactic longitude and latitude directions are Pml and Pmb, respectively. The black curve combines different components (colored curves) and yields a 3D kine￾matic distance of 20.2±3.2 kpc. rable in complexity to that observed near the end … view at source ↗
Figure 5
Figure 5. Figure 5: Spatial distributions of three most distant star-forming regions with precise distance measurements projected onto the Galactic plane. The sources shown in clockwise order are G040.96+02.48 (this work), G034.84−00.95 (Sakai et al. 2023), and G007.47+0.06 (Sanna et al. 2017). The yellow arrow shows the peculiar motion vector of star-forming region G040.96+02.48. A velocity scale of 50 km s−1 is indicated in… view at source ↗
Figure 6
Figure 6. Figure 6: Maximum amplitudes of the northern warp overlaid with the vertical heights of HMSFR masers. Similar to Chen et al. (2019), all maser samples are presented merely to illustrate a simple warping trend. The gray dots indicate the HMSFR masers collected from the literature, while the cyan triangle marks G040.96+02.48. The curves show maximum warp amplitudes derived from different studies: DS01, dust (Drimmel &… view at source ↗
read the original abstract

Accurate astrometric measurements for star-forming regions located on the far side of the Milky Way remain scarce. In this work, we present the astrometric results for a 22\,GHz water maser associated with star-forming region G040.96+02.48 located on the far side of the Milky Way, using the East Asian VLBI Network. The target water maser's proper motion was determined to be ($\mu_{\alpha}\cos\delta, \mu_{\delta}$) = ($-2.06_{-0.51}^{+0.53}$, $-2.95_{-0.44}^{+0.45}$)~mas~yr$^{-1}$. The derived three-dimensional kinematic distance to the star-forming region is 20.2$\pm$3.2\,kpc, placing it slightly outside the Outer Scutum$-$Centaurus Arm. The corresponding vertical height of 872$\pm$139\,pc indicates a significant warp of the outer Galactic disk, which is in good agreement with the latest precessing warp model. Moreover, the resulting peculiar motions reveal a complex kinematic pattern, characterized by a large outward radial velocity of $-32\pm$18\,km~s$^{-1}$. Our observations substantially expand the valuable sample of star-forming regions with accurate astrometric measurements in the Extreme Outer Galaxy.

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

0 major / 2 minor

Summary. The manuscript reports East Asian VLBI Network astrometry of a 22 GHz water maser in star-forming region G040.96+02.48. Proper motions are measured as (μ_α cos δ, μ_δ) = (-2.06_{-0.51}^{+0.53}, -2.95_{-0.44}^{+0.45}) mas yr^{-1}. Using these with radial velocity and a standard rotation curve, the authors derive a kinematic distance of 20.2 ± 3.2 kpc (placing the source slightly outside the Outer Scutum-Centaurus Arm) and a vertical height |z| = 872 ± 139 pc (indicating a warp of the outer disk consistent with precessing models). Peculiar motions are also reported, including a large outward radial velocity component of -32 ± 18 km s^{-1}.

Significance. If the results hold, the work adds one of the few precise astrometric anchors in the Extreme Outer Galaxy, where such measurements remain scarce. The derived distance and height provide direct support for the outer-disk warp and help map far-side Galactic structure and kinematics. The expansion of the sample of regions with VLBI-quality proper motions and distances is a clear strength.

minor comments (2)
  1. [Abstract] The abstract and methods would benefit from explicitly stating the Galactic rotation curve, solar motion parameters, and any assumptions about non-circular motions used to convert observed proper motion and radial velocity into the three-dimensional kinematic distance and peculiar motions.
  2. Figure captions and text could clarify whether the reported asymmetric proper-motion uncertainties come from the formal fit covariance or from a separate error analysis (e.g., Monte Carlo or jackknife).

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive evaluation of our manuscript and for recommending acceptance. The referee's summary accurately captures the key results on the VLBI astrometry, kinematic distance, vertical height, and peculiar motions of G040.96+02.48, and we appreciate the recognition of its value as one of the few precise anchors in the Extreme Outer Galaxy.

Circularity Check

0 steps flagged

No significant circularity; results follow directly from VLBI data and standard formulas

full rationale

The paper reports direct VLBI measurements of proper motion for the water maser, combined with radial velocity and a standard (externally assumed) Galactic rotation curve to compute kinematic distance via the usual three-dimensional conversion. The vertical height follows geometrically from that distance and Galactic latitude. No parameters are fitted to the target data inside the paper, no predictions reduce to the inputs by construction, and no load-bearing uniqueness theorem or ansatz is imported via self-citation. The derivation chain is therefore self-contained against external benchmarks and standard astrometric practice.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on standard VLBI reduction techniques and a Galactic rotation model drawn from prior literature; no new free parameters or invented entities are introduced.

axioms (1)
  • domain assumption Standard Milky Way rotation curve for converting observed velocities to distances and peculiar motions
    Invoked to derive the 3D kinematic distance and radial peculiar motion from proper motion and line-of-sight velocity.

pith-pipeline@v0.9.0 · 5623 in / 1177 out tokens · 78411 ms · 2026-05-08T03:02:28.939494+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

62 extracted references · 60 canonical work pages

  1. [1]

    2022, Galaxies, 10, 113, doi: 10.3390/galaxies10060113

    Akiyama, K., Algaba, J.-C., An, T., et al. 2022, Galaxies, 10, 113, doi: 10.3390/galaxies10060113

    work page doi:10.3390/galaxies10060113 2022

  2. [2]

    Nature Astronomy , archivePrefix = "arXiv", eprint =

    An, T., Sohn, B. W., & Imai, H. 2018, Nature Astronomy, 2, 118, doi: 10.1038/s41550-017-0277-z

    work page doi:10.1038/s41550-017-0277-z 2018

  3. [3]

    D., Armentrout , W

    Anderson, L. D., Armentrout, W. P., Johnstone, B. M., et al. 2015, ApJS, 221, 26, doi: 10.1088/0067-0049/221/2/26

    work page doi:10.1088/0067-0049/221/2/26 2015

  4. [4]

    , keywords =

    Armentrout, W. P., Anderson, L. D., Balser, D. S., et al. 2017, ApJ, 841, 121, doi: 10.3847/1538-4357/aa71a1

    work page doi:10.3847/1538-4357/aa71a1 2017

  5. [5]

    E., & Neugebauer, G

    Becklin, E. E., & Neugebauer, G. 1968, ApJ, 151, 145, doi: 10.1086/149425

    work page doi:10.1086/149425 1968

  6. [6]

    B., Wu, Y

    Bian, S. B., Wu, Y. W., Xu, Y., et al. 2024, AJ, 167, 267, doi: 10.3847/1538-3881/ad4030 EA VN observations of G040.96+02.4811

    work page doi:10.3847/1538-3881/ad4030 2024

  7. [7]

    J., Menten, K

    Brunthaler, A., Reid, M. J., Menten, K. M., et al. 2011, Astronomische Nachrichten, 332, 461, doi: 10.1002/asna.201111560

    work page doi:10.1002/asna.201111560 2011

  8. [8]

    Burke, B. F. 1957, AJ, 62, 90, doi: 10.1086/107463

    work page doi:10.1086/107463 1957

  9. [9]

    2019, Nature Astronomy, 3, 320, doi: 10.1038/s41550-018-0686-7

    Chen, X., Wang, S., Deng, L., et al. 2019, Nature Astronomy, 3, 320, doi: 10.1038/s41550-018-0686-7 Chrob´ akov´ a,ˇZ., Nagy, R., & L´ opez-Corredoira, M. 2022, A&A, 664, A58, doi: 10.1051/0004-6361/202243296

    work page doi:10.1038/s41550-018-0686-7 2019

  10. [10]

    M., & Thaddeus, P

    Dame, T. M., & Thaddeus, P. 2011, ApJL, 734, L24, doi: 10.1088/2041-8205/734/1/L24

    work page doi:10.1088/2041-8205/734/1/l24 2011

  11. [11]

    , keywords =

    Digel, S., de Geus, E., & Thaddeus, P. 1994, ApJ, 422, 92, doi: 10.1086/173706

    work page doi:10.1086/173706 1994

  12. [12]

    2003, A&A, 409, 205, doi: 10.1051/0004-6361:20031070

    Drimmel, R., Cabrera-Lavers, A., & L´ opez-Corredoira, M. 2003, A&A, 409, 205, doi: 10.1051/0004-6361:20031070

    work page doi:10.1051/0004-6361:20031070 2003

  13. [13]

    Drimmel, R., & Spergel, D. N. 2001, ApJ, 556, 181, doi: 10.1086/321556

    work page doi:10.1086/321556 2001

  14. [14]

    2010, in Astronomical Society of the Pacific Conference Series, Vol

    Foster, T., & Cooper, B. 2010, in Astronomical Society of the Pacific Conference Series, Vol. 438, The Dynamic Interstellar Medium: A Celebration of the Canadian Galactic Plane Survey, ed. R. Kothes, T. L. Landecker, & A. G. Willis, 16, doi: 10.48550/arXiv.1009.3220 Gaia Collaboration, Brown, A. G. A., Vallenari, A., et al. 2018, A&A, 616, A1, doi: 10.105...

    work page doi:10.48550/arxiv.1009.3220 2010

  15. [15]

    Greisen, E. W. 2003, in Astrophysics and Space Science

    2003

  16. [16]

    285, Information Handling in Astronomy - Historical Vistas, ed

    Library, Vol. 285, Information Handling in Astronomy - Historical Vistas, ed. A. Heck, 109, doi: 10.1007/0-306-48080-8 7

    work page doi:10.1007/0-306-48080-8

  17. [17]

    S., Kerr, F

    Gum, C. S., Kerr, F. J., & Westerhout, G. 1960, MNRAS, 121, 132, doi: 10.1093/mnras/121.2.132

    work page doi:10.1093/mnras/121.2.132 1960

  18. [18]

    M., et al

    Hachisuka, K., Brunthaler, A., Menten, K. M., et al. 2006, ApJ, 645, 337, doi: 10.1086/502962

    work page doi:10.1086/502962 2006

  19. [19]

    J., Xu, Y., Hou, L

    Hao, C. J., Xu, Y., Hou, L. G., et al. 2021, A&A, 652, A102, doi: 10.1051/0004-6361/202140608

    work page doi:10.1051/0004-6361/202140608 2021

  20. [20]

    2023, ApJL, 954, L9, doi: 10.3847/2041-8213/ace77d

    He, Z. 2023, ApJL, 954, L9, doi: 10.3847/2041-8213/ace77d

    work page doi:10.3847/2041-8213/ace77d 2023

  21. [21]

    2012, PASJ, 64, 136, doi: 10.1093/pasj/64.6.136

    Honma, M., Nagayama, T., Ando, K., et al. 2012, PASJ, 64, 136, doi: 10.1093/pasj/64.6.136

    work page doi:10.1093/pasj/64.6.136 2012

  22. [22]

    Hou, L. G. 2021, Frontiers in Astronomy and Space Sciences, 8, 103, doi: 10.3389/fspas.2021.671670

    work page doi:10.3389/fspas.2021.671670 2021

  23. [23]

    Kerr, F. J. 1957, AJ, 62, 93, doi: 10.1086/107466

    work page doi:10.1086/107466 1957

  24. [24]

    2006, in Astronomical Society of the Pacific Conference Series, Vol

    Cotton, B. 2006, in Astronomical Society of the Pacific Conference Series, Vol. 351, Astronomical Data Analysis Software and Systems XV, ed. C. Gabriel, C. Arviset, D. Ponz, & S. Enrique, 497

    2006

  25. [25]

    S., Blitz, L., & Heiles, C

    Levine, E. S., Blitz, L., & Heiles, C. 2006, ApJ, 643, 881, doi: 10.1086/503091

    work page doi:10.1086/503091 2006

  26. [26]

    2022, ApJ, 931, 72, doi: 10.3847/1538-4357/ac67a6

    Lin, Z., Xu, Y., Hou, L., et al. 2022, ApJ, 931, 72, doi: 10.3847/1538-4357/ac67a6

    work page doi:10.3847/1538-4357/ac67a6 2022

  27. [27]

    2023, ApJS, 268, 46, doi: 10.3847/1538-4365/acf3e3 L´ opez-Corredoira, M., Cabrera-Lavers, A., Garz´ on, F., &

    Liu, D., Xu, Y., Hao, C., et al. 2023, ApJS, 268, 46, doi: 10.3847/1538-4365/acf3e3 L´ opez-Corredoira, M., Cabrera-Lavers, A., Garz´ on, F., &

    work page doi:10.3847/1538-4365/acf3e3 2023

  28. [28]

    Hammersley, P. L. 2002, A&A, 394, 883, doi: 10.1051/0004-6361:20021175

    work page doi:10.1051/0004-6361:20021175 2002

  29. [29]

    2006, A&A, 453, 635, doi: 10.1051/0004-6361:20053842

    Picaud, S. 2006, A&A, 453, 635, doi: 10.1051/0004-6361:20053842

    work page doi:10.1051/0004-6361:20053842 2006

  30. [30]

    2006, A&A, 451, 515, doi: 10.1051/0004-6361:20054081

    Momany, Y., Zaggia, S., Gilmore, G., et al. 2006, A&A, 451, 515, doi: 10.1051/0004-6361:20054081

    work page doi:10.1051/0004-6361:20054081 2006

  31. [31]

    W., Whitford, A

    Morgan, W. W., Whitford, A. E., & Code, A. D. 1953, ApJ, 118, 318, doi: 10.1086/145754

    work page doi:10.1086/145754 1953

  32. [32]

    2020, Nature Astronomy, 4, 590, doi: 10.1038/s41550-020-1017-3

    Poggio, E., Drimmel, R., Andrae, R., et al. 2020, Nature Astronomy, 4, 590, doi: 10.1038/s41550-020-1017-3

    work page doi:10.1038/s41550-020-1017-3 2020

  33. [33]

    G., et al

    Poggio, E., Drimmel, R., Lattanzi, M. G., et al. 2018, MNRAS, 481, L21, doi: 10.1093/mnrasl/sly148

    work page doi:10.1093/mnrasl/sly148 2018

  34. [34]

    2021, A&A, 651, A104, doi: 10.1051/0004-6361/202140687

    Poggio, E., Drimmel, R., Cantat-Gaudin, T., et al. 2021, A&A, 651, A104, doi: 10.1051/0004-6361/202140687

    work page doi:10.1051/0004-6361/202140687 2021

  35. [35]

    2025, A&A, 699, A199, doi: 10.1051/0004-6361/202451668

    Poggio, E., Khanna, S., Drimmel, R., et al. 2025, A&A, 699, A199, doi: 10.1051/0004-6361/202451668

    work page doi:10.1051/0004-6361/202451668 2025

  36. [36]

    Reid, M. J. 2022, AJ, 164, 133, doi: 10.3847/1538-3881/ac80bb

    work page doi:10.3847/1538-3881/ac80bb 2022

  37. [37]

    Reid, M. J. 2024, in IAU Symposium, Vol. 380, Cosmic Masers: Proper Motion Toward the Next-Generation Large Projects, ed. T. Hirota, H. Imai, K. Menten, & Y. Pihlstr¨ om, 111–115, doi: 10.1017/S1743921323002211

    work page doi:10.1017/s1743921323002211 2024

  38. [38]

    J., & Honma, M

    Reid, M. J., & Honma, M. 2014, ARA&A, 52, 339, doi: 10.1146/annurev-astro-081913-040006

    work page doi:10.1146/annurev-astro-081913-040006 2014

  39. [39]

    J., Menten, K

    Reid, M. J., Menten, K. M., Brunthaler, A., et al. 2009a, ApJ, 693, 397, doi: 10.1088/0004-637X/693/1/397

    work page doi:10.1088/0004-637x/693/1/397

  40. [40]

    J., Menten, K

    Reid, M. J., Menten, K. M., Zheng, X. W., et al. 2009b, ApJ, 700, 137, doi: 10.1088/0004-637X/700/1/137

    work page doi:10.1088/0004-637x/700/1/137

  41. [41]

    J., Menten, K

    Reid, M. J., Menten, K. M., Brunthaler, A., et al. 2019, ApJ, 885, 131, doi: 10.3847/1538-4357/ab4a11 Romero-G´ omez, M., Mateu, C., Aguilar, L., Figueras, F., &

    work page doi:10.3847/1538-4357/ab4a11 2019

  42. [42]

    2019, A&A, 627, A150, doi: 10.1051/0004-6361/201834908

    Castro-Ginard, A. 2019, A&A, 627, A150, doi: 10.1051/0004-6361/201834908

    work page doi:10.1051/0004-6361/201834908 2019

  43. [43]

    2023, PASJ, 75, 208, doi: 10.1093/pasj/psac102

    Sakai, N., Zhang, B., Xu, S., et al. 2023, PASJ, 75, 208, doi: 10.1093/pasj/psac102

    work page doi:10.1093/pasj/psac102 2023

  44. [44]

    2017, Science, 358, 227, doi: 10.1126/science.aan5452

    Brunthaler, A. 2017, Science, 358, 227, doi: 10.1126/science.aan5452

    work page doi:10.1126/science.aan5452 2017

  45. [45]

    2020, Research in Astronomy and Astrophysics, 20, 159, doi: 10.1088/1674-4527/20/10/159

    Shen, J., & Zheng, X.-W. 2020, Research in Astronomy and Astrophysics, 20, 159, doi: 10.1088/1674-4527/20/10/159

    work page doi:10.1088/1674-4527/20/10/159 2020

  46. [46]

    J., Hou, L

    Shen, X. J., Hou, L. G., Liu, H. L., & Gao, X. Y. 2025, A&A, 696, A67, doi: 10.1051/0004-6361/202452712

    work page doi:10.1051/0004-6361/202452712 2025

  47. [47]

    M., Skowron, J., Mr´ oz, P., et al

    Skowron, D. M., Skowron, J., Mr´ oz, P., et al. 2019, Science, 365, 478, doi: 10.1126/science.aau3181

    work page doi:10.1126/science.aau3181 2019

  48. [48]

    2019, ApJS, 240, 9, doi: 10.3847/1538-4365/aaf1c8

    Su, Y., Yang, J., Zhang, S., et al. 2019, ApJS, 240, 9, doi: 10.3847/1538-4365/aaf1c8 12Shen et al

    work page doi:10.3847/1538-4365/aaf1c8 2019

  49. [49]

    2017, ApJS, 230, 17, doi: 10.3847/1538-4365/aa63ea

    Sun, Y., Su, Y., Zhang, S.-B., et al. 2017, ApJS, 230, 17, doi: 10.3847/1538-4365/aa63ea

    work page doi:10.3847/1538-4365/aa63ea 2017

  50. [50]

    , keywords =

    Sun, Y., Xu, Y., Yang, J., et al. 2015, ApJL, 798, L27, doi: 10.1088/2041-8205/798/2/L27

    work page doi:10.1088/2041-8205/798/2/l27 2015

  51. [51]

    2018, ApJ, 869, 148, doi: 10.3847/1538-4357/aaee86

    Sun, Y., Xu, Y., Chen, X., et al. 2018, ApJ, 869, 148, doi: 10.3847/1538-4357/aaee86

    work page doi:10.3847/1538-4357/aaee86 2018

  52. [52]

    2021, ApJS, 256, 32, doi: 10.3847/1538-4365/ac11fe

    Sun, Y., Yang, J., Yan, Q.-Z., et al. 2021, ApJS, 256, 32, doi: 10.3847/1538-4365/ac11fe

    work page doi:10.3847/1538-4365/ac11fe 2021

  53. [53]

    , keywords =

    Sun, Y., Yang, J., Zhang, S., et al. 2024, ApJL, 977, L35, doi: 10.3847/2041-8213/ad9605 van Moorsel, G., Kemball, A., & Greisen, E. 1996, in Astronomical Society of the Pacific Conference Series, Vol. 101, Astronomical Data Analysis Software and Systems V, ed. G. H. Jacoby & J. Barnes, 37 VERA Collaboration, Hirota, T., Nagayama, T., et al. 2020, PASJ, 7...

    work page doi:10.3847/2041-8213/ad9605 2024

  54. [54]

    J., Liu, D

    Xu, Y., Hao, C. J., Liu, D. J., et al. 2023, ApJ, 947, 54, doi: 10.3847/1538-4357/acc45c

    work page doi:10.3847/1538-4357/acc45c 2023

  55. [55]

    G., Bian, S

    Xu, Y., Hou, L. G., Bian, S. B., et al. 2021a, A&A, 645, L8, doi: 10.1051/0004-6361/202040103

    work page doi:10.1051/0004-6361/202040103

  56. [56]

    Research in Astronomy and Astrophysics , keywords =

    Xu, Y., Hou, L.-G., & Wu, Y.-W. 2018, Research in Astronomy and Astrophysics, 18, 146, doi: 10.1088/1674-4527/18/12/146

    work page doi:10.1088/1674-4527/18/12/146 2018

  57. [57]

    J., Zheng, X

    Xu, Y., Reid, M. J., Zheng, X. W., & Menten, K. M. 2006, Science, 311, 54, doi: 10.1126/science.1120914

    work page doi:10.1126/science.1120914 2006

  58. [58]

    B., Reid, M

    Xu, Y., Bian, S. B., Reid, M. J., et al. 2021b, ApJS, 253, 1, doi: 10.3847/1538-4365/abd8cf

    work page doi:10.3847/1538-4365/abd8cf

  59. [59]

    2016, PASJ, 68, 60, doi: 10.1093/pasj/psw058

    Yamauchi, A., Yamashita, K., Honma, M., et al. 2016, PASJ, 68, 60, doi: 10.1093/pasj/psw058

    work page doi:10.1093/pasj/psw058 2016

  60. [60]

    2026, ApJS, 282, 65, doi: 10.3847/1538-4365/ae29e7

    Yang, J., Yan, Q.-Z., Su, Y., et al. 2026, ApJS, 282, 65, doi: 10.3847/1538-4365/ae29e7

    work page doi:10.3847/1538-4365/ae29e7 2026

  61. [61]

    2021, ApJ, 922, 80, doi: 10.3847/1538-4357/ac1e91

    Yu, Y., Wang, H.-F., Cui, W.-Y., et al. 2021, ApJ, 922, 80, doi: 10.3847/1538-4357/ac1e91

    work page doi:10.3847/1538-4357/ac1e91 2021

  62. [62]

    Pulsars and the Warp of the Galaxy

    Yusifov, I. 2004, in The Magnetized Interstellar Medium, ed. B. Uyaniker, W. Reich, & R. Wielebinski, 165–169, doi: 10.48550/arXiv.astro-ph/0405517

    work page Pith review doi:10.48550/arxiv.astro-ph/0405517 2004