Pith. sign in

REVIEW 3 major objections 4 minor 66 references

Molecular envelope around the HII region RCW 120

T0 review · 3 major / 4 minor · reviewed 2026-08-14 · deepseek-v4-flash

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

Pith's one-line read RCW 120, one of the most studied infrared bubbles in the Milky Way, is an oblate ring-like molecular envelope seen face-on rather than a spherical expanding shell.

desk verdict Solid, honest phenomenological case that RCW 120's molecular envelope is a face-on torus rather than a sphere, but the untested foreground-absorption alternative leaves a real gap that a referee should ask them to close. read the letter →

arxiv 1908.05394 v1 pith:TAIBDTPN submitted 2019-08-15 astro-ph.SR astro-ph.GA

M. S. Kirsanova , Ya N. Pavlyuchenkov , D. S. Wiebe , P. A. Boley , S. V. Salii , S. V. Kalenskii , A. M. Sobolev , L. D Anderson This is my paper · ORCID
classification astro-ph.SRastro-ph.GA
keywords RCW120HIIregiongeometrymolecularenvelopeinfraredbubbleCOisotopologuesradiativetransfermodellinginterstellarextinctiontriggeredstarformation
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

This paper tries to settle the long-debated geometry of RCW 120, a nearby H II region whose infrared image is an almost perfect ring. The authors argue that the molecular envelope around RCW 120 is an oblate, torus-like structure seen face-on, not the spherical expanding shell of the standard picture. Their case rests on the failure of a spherically symmetric model, which predicts bright carbon-monoxide emission from the front and back walls across the entire interior of the H II region, where the observations show essentially no molecular emission; a two-dimensional ring model reproduces the observed integrated intensities and position–velocity diagrams. The paper also proposes a diffuse foreground molecular cloud to explain the deep self-absorption dips in the 13CO lines, and finds support for that cloud in near-infrared extinction maps. If true, this changes how RCW 120 is used as a template for triggered star formation and for the interaction of massive stars with their parent molecular clouds.

What carries the argument

The argument is carried by synthetic emission-line modelling: the MARION code provides a one-dimensional spherical model of an expanding H II region with a dense compressed molecular shell, and the URAN(IA) code solves the two-dimensional non-LTE line transfer to produce synthetic 13CO and C18O position–velocity diagrams. The decisive geometric move is cutting the conical caps off the spherical dense shell to form a face-on torus; the synthetic PV diagrams of the torus, viewed along its axis, lose the bright interior emission that the intact sphere cannot avoid, and match the observed ring-like maps. A supporting layer is the LTE column-density analysis of 13CO and C18O, and near-infrared extinction mapping that reveals the foreground diffuse cloud invoked for self-absorption.

What would settle it

Measure the foreground cloud's 13CO(2–1) opacity toward the centre of RCW 120 in absorption against the free-free continuum: if the cloud is thick enough to absorb the central emission predicted by the spherical model, the ring interpretation is not forced; a deep, high-resolution C18O(2–1) map of the centre should then show no near/far wall velocity components if the torus is real.

Watch

Extended reading notes

Core claim

The central claim is that RCW 120's surrounding neutral material is a flattened, ring-like molecular envelope, a torus seen nearly face-on, rather than a spherical bubble. The evidence is that the observed integrated intensities of the 13CO(2–1) and C18O(2–1) lines, together with their position–velocity diagrams, are reproduced by a two-dimensional model in which the conical parts of the dense shell are removed and the line of sight runs parallel to the polar axis; the spherical model cannot remove the predicted bright, double-peaked CO emission from the interior that is not seen. A diffuse foreground molecular cloud, traced in near-infrared extinction maps over a region about 11.3 pc across, is invoked to explain the deep self-absorption dips in the 13CO lines. The paper also finds that optically thick tracers, 13CO and the 8 µm PAH band, show a continuous ring, while optically thin tracers, C18O and far-infrared dust, break the envelope into separate clumps and reveal discontinuities where ionizing radiation leaks out.

Load-bearing premise

The diffuse foreground cloud invoked to explain the self-absorption dips is not so optically thick at the 13CO frequencies that it would also absorb the bright central emission that a spherical shell would produce; if it were, the observed absence of central CO emission would be an absorption artifact rather than evidence for a ring.

Editorial extensions

If this is right

  • If RCW 120 is a face-on torus, its H II region is expanding into a flattened parent cloud, and line-of-sight velocity measurements will systematically miss most of the expansion.
  • The fitted torus has a molecular shell thickness of about 16% of the H II region radius, with the extent along the line of sight varying from about 50% to 90% of the radius depending on impact parameter.
  • The deep self-absorption dips in the 13CO(2–1) and 13CO(3–2) lines require foreground gas rather than the torus alone, and the proposed diffuse cloud of density about 50 cm^-3 and sky-plane size about 11.3 pc is independently visible in extinction maps.
  • Optically thick tracers, 13CO(2–1) and the 8 µm PAH band, show a continuous neutral ring around RCW 120, while optically thin tracers, C18O(2–1) and far-infrared dust, resolve the same envelope into separate clumps and reveal discontinuities where ultraviolet radiation leaks out.
  • If RCW 120 is typical, infrared bubbles catalogued as three-dimensional shells may generally be rings in flattened clouds, which would change how the collected mass and the potential for triggered star formation are inferred from images.

Reading between the lines

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

  • The optically thick versus optically thin tracer comparison could be applied to other Spitzer bubbles with existing molecular-line and far-infrared data, offering a geometric screen that does not require full hydrodynamic modelling of each object.
  • A face-on torus geometry would change the interpretation of the dense condensations around RCW 120: they would sit in a flattened disc-like cloud rather than in a spherical swept-up shell, so gravitational-instability and triggering analyses would need to be reworked.
  • A direct test of the torus picture is to search, in the centre of RCW 120, for the second velocity component that a spherical shell would put on the far side of the H II region; high-sensitivity observations in an optically thin tracer such as C18O should find no such component.
  • The foreground-cloud explanation predicts that 13CO self-absorption should also appear in absorption against the H II region's radio continuum, a signature that could be checked with existing or new interferometric observations.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

3 major / 4 minor

Summary. This paper presents new APEX observations of 13CO(2–1), C18O(2–1), 13CO(3–2), and C18O(3–2) toward the HII region RCW 120, together with analysis of archival data and infrared extinction maps. The authors use the spherically symmetric MARION hydrodynamic model and the URAN(IA) non-LTE radiative transfer code to compute synthetic PV diagrams. They show that a spherical expanding shell model predicts bright double-peaked CO emission from the central region, which is not observed. By manually truncating the spherical shell into a face-on torus (removing the conical caps), the synthetic PV diagrams become consistent with the observed absence of central emission and with the observed line shapes in the envelope. To explain self-absorption dips in 13CO lines, the authors introduce a diffuse foreground molecular cloud and claim support from a 2MASS/NICEST extinction map. They conclude that RCW 120 is a face-on torus/ring-like structure rather than a spherical shell.

Significance. The paper addresses a long-standing question about the geometry of infrared bubbles and HII regions. If the face-on torus interpretation is correct, it would support the idea that many Spitzer bubbles are flattened/ring-like structures, with implications for triggered star formation and for interpreting column density maps. The work benefits from new APEX observations and a clear presentation of the spherical-versus-torus discrepancy. A notable strength is the authors' transparency: they explicitly acknowledge that the torus is a manually imposed geometry, not a self-consistent hydrodynamic model, and that the foreground cloud is a phenomenological addition. However, the central claim is not yet quantitatively established, primarily because the foreground cloud is not tested against the spherical model and because the model comparison is qualitative.

major comments (3)
  1. [§4.1 and §4.2] The rejection of the spherical shell model is incomplete because the foreground absorbing cloud introduced in §4.2 is never inserted into the spherical model. The spherical model is rejected on the basis of bright central CO emission that is absent in the observations (Fig. 7), but the quoted foreground cloud parameters (N13CO up to 1e17 cm^-2, Tgas=10 K, Vnth=1 km/s) can produce large optical depth in 13CO(2-1), as the authors' own RADEX calculation shows (Tex below the observed 14-16 K, the condition for absorption). If such a cloud lies in front of the HII region, it could attenuate the front and back walls of a spherical shell by a factor e^-τ and hide the central emission, making the observed hole an absorption artifact rather than evidence for torus geometry. The authors must either include the foreground cloud in the spherical model and show that the central emission remains above the observed threshold, or quantify the cloud's optical depth and rule out this degeneracy.
  2. [§3.4 and §4.2] The adopted foreground cloud parameters appear inconsistent with the extinction data used to support the cloud's existence. Toward the ionizing star the authors measure AV=8-12 mag and infer an extended cloud of 11.3 pc (§3.4). A foreground column of even a fraction of this AV corresponds to a molecular hydrogen column far exceeding that of the tested 50 cm^-3 × 1 pc cloud (N(H2) ≈ 1.5e20 cm^-2, giving N13CO ≈ 3e14 cm^-2 at the adopted 13C abundance, well below the 1e17 cm^-2 upper limit used in the RADEX calculation). The paper does not demonstrate that a cloud consistent with the extinction map has sufficiently low 13CO optical depth to preserve the spherical model's central emission, nor does it explore the allowed parameter space. The self-absorption interpretation—and the geometry conclusion that depends on it—therefore needs a self-consistent column-density budget.
  3. [§4.2 and Abstract] The comparison between observed and synthetic PV diagrams is qualitative. The abstract states that the lines 'are fitted' by a 2D model, but no quantitative goodness-of-fit measure (e.g., χ², residual maps, or profile comparison at fixed positions) is provided. Observed profiles vary strongly across the region (§3.3), and the model is compared by eye with selected cuts (Figs. 3, 8). Given the foreground-absorption degeneracy, a quantitative test is needed to determine whether the torus model is actually preferred over a spherical model with a foreground screen.
minor comments (4)
  1. [§2.4 and §4] In §2.4, 'ngas = 3 · 103 cm−1' should be '10^3 cm^-3'; in §4, 'nH+ ≈ 102 cm−2' should be 'cm^-3'.
  2. [§4.2] 'testified' should be 'tested'.
  3. [§3.4] The sentence 'Sharp linear absorption across the face of the H ii region is visible at optical wavelengths (see also H α images by ...) might be a part of the absorbing cloud' is a fragment and should be rephrased.
  4. [§2.4] 'adopted as a the age' should be 'adopted as the age'.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the torus conclusion is a model comparison against independent APEX/SEDIGISM and extinction data, and the torus is explicitly phenomenological rather than a derived prediction.

full rationale

The paper's central geometric claim is not obtained by circular reduction. The spherical MARION model is a forward model whose parameters are set before comparing with the CO data; its failure to reproduce the observed absence of central emission is a nontrivial falsification of that model. The torus model is then introduced openly as an illustration: the authors state they 'illustrate the associated geometrical effects by manually modifying our simpler spherically symmetric model' and remove 'conical parts of the dense layer.' This means the absence of central emission in the torus model is an input property, not a prediction from first principles; the paper does not disguise the manual construction as independent confirmation. The self-citations to MARION, URAN(IA), and prior Pavlyuchenkov/Akimkin simulations are tool provenance and parameter choices, not load-bearing external theorems; the models are tested against observational data in the present paper. The foreground cloud invoked for self-absorption is supported by an independent extinction map. The skeptical concern that the foreground cloud could also absorb the spherical model's central emission is a genuine untested degeneracy and a correctness risk, but it is not a circularity because the paper never claims to have excluded that scenario. Overall, the derivation is largely self-contained against external data, with only minor self-citation weight, so the circularity score is low.

Assumptions & free parameters 9 free parameters · 6 assumptions · 1 invented entities

The central geometry claim rests on a small set of adopted parameters (density, age, microturbulence, cloud properties, face-on viewing) that are tuned to RCW 120. The foreground cloud is the only newly introduced physical component, and it has independent support from extinction data, though its parameters are not directly measured.

free parameters (9)
  • Initial hydrogen number density in MARION model = 10^4 cm^-3
    Raised from 3x10^3 cm^-3 to obtain a better fit to observed dust intensities at 100-500 um (Pavlyuchenkov et al., in prep); directly controls the dense shell density and CO line brightness.
  • Age of the HII region = 590 kyr
    Chosen as the time required for the dense molecular layer to reach the 1.2 pc radius of the envelope; scales with assumed distance.
  • Microturbulent velocity Vnth = 0.3 and 1.0 km/s
    Two values tested; 1.0 km/s adopted because observed line widths are several km/s. Broadens synthetic lines to match data.
  • Foreground cloud gas density = 50 cm^-3
    Adopted to reproduce the self-absorption depth in 13CO lines; part of a model of the extended diffuse cloud.
  • Foreground cloud thickness = 1 pc
    Adopted for the model cloud; no physical justification beyond plausibility.
  • Foreground cloud temperature = 10 K
    Adopted as the cold cloud temperature; RADEX runs up to 2000 K show Tex remains below observed Tmb.
  • Outer radius of undisturbed envelope = 1.6 pc
    Adopted because molecular emission is seen up to 300 arcsec offset from the ionizing star at 1.3 kpc.
  • Torus geometry (removal of conical caps)
    The spherical model is manually modified by removing conical parts of the dense layer to create a face-on torus; the exact shape and opening angle are not quantified.
  • Distance to RCW 120 = 1.3 kpc
    Adopted from Russeil (2003) for consistency with prior work, despite Gaia DR2 parallax suggesting 0.5-1.1 kpc; sets physical scales.
assumptions (6)
  • domain assumption MARION hydrodynamic and chemical model correctly describes the expansion of an HII region into a molecular cloud.
    The paper adopts the MARION code from Kirsanova et al. 2009 and Pavlyuchenkov et al. 2013 without re-justifying its physical formulations.
  • domain assumption URAN(IA) non-LTE radiative transfer code correctly computes line profiles given density, temperature, velocity and abundance fields.
    The model line emission is computed with URAN(IA) (Pavlyuchenkov & Shustov 2004; Pavlyuchenkov et al. 2008), which is assumed valid.
  • domain assumption A constant excitation temperature along the line of sight for 13CO and C18O in the LTE column density analysis.
    Column densities are derived via the LTE method of Mangum & Shirley (2015) with an implicit constant Tex.
  • domain assumption The diffuse extinction cloud visible in the 2MASS/NICEST map is physically associated with RCW 120 rather than an unrelated foreground or background cloud.
    The cloud is proposed to explain self-absorption; the paper argues association from angular proximity but this is an assumption.
  • ad hoc to paper The self-absorption dip in 13CO lines is caused by the foreground diffuse cloud rather than by local clumps or condensations.
    The authors acknowledge the alternative and prefer the cloud hypothesis based on the persistence of self-absorption beyond condensations; this is a model choice.
  • ad hoc to paper The face-on torus geometry is a valid representation of the actual 3D structure, with the line of sight parallel to the symmetry axis.
    The torus is imposed by removing caps from a spherical model and viewing it pole-on; no self-consistent 2D or 3D hydrodynamical simulation is performed.
invented entities (1)
  • Diffuse foreground molecular cloud independent evidence
    purpose: Produces the self-absorption dips in 13CO(2-1) and 13CO(3-2) lines and explains the deep absorption that the torus model alone cannot reproduce.
    Supported by the 2MASS/NICEST extinction map (Fig. 5) showing an extended AV ~ 8-12 mag cloud, and by obscuration of background stars; however, its physical association and exact parameters are inferred, not measured.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Molecular envelope around the HII region RCW 120." pith.science (2026). https://pith.science/paper/TAIBDTPN

@misc{pith2026190805394,
  author       = {Pith},
  title        = {Pith review of: Molecular envelope around the HII region RCW 120},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/TAIBDTPN}},
  note         = {Machine review of arXiv:1908.05394}
}
read the original abstract

The H II region RCW120 is a well-known object, which is often considered as a target to verify theoretical models of gas and dust dynamics in the interstellar medium. However, the exact geometry of RCW120 is still a matter of debate. In this work, we analyse observational data on molecular emission in RCW120 and show that 13CO(2-1) and C18O(2-1) lines are fitted by a 2D model representing a ring-like face-on structure. The changing of the C18O(3-2) line profile from double-peaked to single-peaked from the dense molecular Condensation 1 might be a signature of stalled expansion in this direction. In order to explain a self-absorption dip of the 13CO(2-1) and 13CO(3-2) lines, we suggest that RCW120 is surrounded by a diffuse molecular cloud, and find confirmation of this cloud on a map of interstellar extinction. Optically thick 13CO(2-1) emission and the infrared 8 um PAH band form a neutral envelope of the H II region resembling a ring, while the envelope breaks into separate clumps on images made with optically thin C18O(2-1) line and far-infrared dust emission.

Figures

Figures reproduced from arXiv: 1908.05394 by the authors.

Figure 1
Figure 1. 13CO(2–1) line intensity integrated over the −20 to 0 km s−1 velocity range. The original 13CO(2–1) data was smoothed and regridded to reach noise level of 1 K. Only pix￾els with the intensity higher than 6 K km s−1 are shown. The pixel size is 20′′×20′′. Black circles show the locations of compact sources described by Figueira et al. (2017) (their [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 3
Figure 3. PV diagrams for 13CO(2–1) (left) and C18O(2–1) (right) using APEX archive data for Condensation 1 (rows 1– 3) and Condensation 2 (rows 4–5). The original 13CO(2–1) data was smoothed and regridded to reach noise level of 1 K. The projected distance between the compact sources and the ioniz￾ing star are shown as white dashed lines (the source are des￾ignated as S1, S2 etc). Top to bottom: PV diagrams for ϕ = 29.0, 37.… view at source ↗
Figure 5
Figure 5. Extinction map in AJ units around RCW 120. White contour shows ATLASGAL 870 µm emission. Note the cut-off of the 870 µm image on the right side of the map. cloudlets in the 12 µm WISE image, delineating the bor￾der of the absorbing cloud. Sharp linear absorption across the face of the H ii region is visible at optical wavelengths (see also Hα images by Zavagno et al. 2007; Anderson et al. 2015) might be a part of th… view at source ↗
Figures from the paper (5 more)
Figure 4
Figure 4. Figure 4: Spectra in Condensation 1. 13CO(2–1), 13CO(3–2) and C18O(3–2) lines are shown with black, green and blue lines, re￾spectively. 13CO(2–1) integrated intensity map from [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 6
Figure 6. Figure 6: Modelled chemical composition and physical condi￾tions in the dense molecular shell around the H ii region. a) abun￾dances of H+, H and H2, b) gas temperature, c) abundances of C++, C+, and CO, d) gas velocity. 4.1 Line emission in a spherically-symmetric molecular she…
Figure 7
Figure 7. Figure 7: PV diagrams for a spherical molecular envelope around the H ii region, based on the original MARION results (top row), and calculated with reduced CO abundances (bottom row). The direction to the observer is shown as a yellow arrow in the left panel. Dashed vertical li…
Figure 8
Figure 8. Figure 8: PV diagrams for the torus envelope around the H ii region. The direction to the observer is shown as a yellow arrow in the left panel. Dashed vertical lines show location of the dense compressed shell. Red line shows location of the density peak. Microturbulent velocit…
Figure 9
Figure 9. Figure 9: Left: 13CO(2–1) integrated intensity (red contours) overlaid on Spitzer image at 8 µm. The contours are for 4.5, 20.0 and 30.0 K km s−1 . Black circles show locations of YSOs described by Figueira et al. (2017). The position of the ionizing star of RCW 120 is marked as…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

66 extracted references · 12 canonical work pages

  1. [1]

    V., Kirsanova M

    Akimkin V. V., Kirsanova M. S., Pavlyuchenkov Y. N., Wiebe D. S., 2015, @doi [ ] 10.1093/mnras/stv187 , http://esoads.eso.org/abs/2015MNRAS.449..440A 449, 440

    doi:10.1093/mnras/stv187 2015

  2. [2]

    V., Kirsanova M

    Akimkin V. V., Kirsanova M. S., Pavlyuchenkov Y. N., Wiebe D. S., 2017, @doi [ ] 10.1093/mnras/stx797 , http://esoads.eso.org/abs/2017MNRAS.469..630A 469, 630

    doi:10.1093/mnras/stx797 2017

  3. [3]

    D., et al., 2010, @doi [ ] 10.1051/0004-6361/201014657 , http://adsabs.harvard.edu/abs/2010A

    Anderson L. D., et al., 2010, @doi [ ] 10.1051/0004-6361/201014657 , http://adsabs.harvard.edu/abs/2010A

    doi:10.1051/0004-6361/201014657 2010

  4. [4]

    D., Bania T

    Anderson L. D., Bania T. M., Balser D. S., Rood R. T., 2011, @doi [ ] 10.1088/0067-0049/194/2/32 , http://adsabs.harvard.edu/abs/2011ApJS..194...32A 194, 32

    doi:10.1088/0067-0049/194/2/32 2011

  5. [5]

    D., Zavagno A., Barlow M

    Anderson L. D., Zavagno A., Barlow M. J., Garc \' a-Lario P., Noriega-Crespo A., 2012, @doi [ ] 10.1051/0004-6361/201117640 , http://esoads.eso.org/abs/2012A

    doi:10.1051/0004-6361/201117640 2012

  6. [6]

    D., Bania T

    Anderson L. D., Bania T. M., Balser D. S., Cunningham V., Wenger T. V., Johnstone B. M., Armentrout W. P., 2014, @doi [ ] 10.1088/0067-0049/212/1/1 , http://adsabs.harvard.edu/abs/2014ApJS..212....1A 212, 1

    doi:10.1088/0067-0049/212/1/1 2014

  7. [7]

    D., et al., 2015, @doi [ ] 10.1088/0004-637X/800/2/101 , http://esoads.eso.org/abs/2015ApJ...800..101A 800, 101

    Anderson L. D., et al., 2015, @doi [ ] 10.1088/0004-637X/800/2/101 , http://esoads.eso.org/abs/2015ApJ...800..101A 800, 101

    doi:10.1088/0004-637x/800/2/101 2015

  8. [8]

    J., Henney W

    Arthur S. J., Henney W. J., Mellema G., de Colle F., V \'a zquez-Semadeni E., 2011, @doi [ ] 10.1111/j.1365-2966.2011.18507.x , http://adsabs.harvard.edu/abs/2011MNRAS.414.1747A 414, 1747

    arXiv 2011

Show all 66 references
  1. [9]

    Astropy Collaboration et al., 2013, @doi [ ] 10.1051/0004-6361/201322068 , http://adsabs.harvard.edu/abs/2013A

    2013 doi

  2. [10]

    N., Williams J

    Beaumont C. N., Williams J. P., 2010, @doi [ ] 10.1088/0004-637X/709/2/791 , http://adsabs.harvard.edu/abs/2010ApJ...709..791B 709, 791

    2010 doi

  3. [11]

    Belitsky V., et al., 2006, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series. p. 62750G, @doi 10.1117/12.671383

    2006 doi

  4. [12]

    G., et al., 2015, @doi [ ] 10.1093/mnras/stv1659 , http://adsabs.harvard.edu/abs/2015MNRAS.453.1324B 453, 1324

    Bisbas T. G., et al., 2015, @doi [ ] 10.1093/mnras/stv1659 , http://adsabs.harvard.edu/abs/2015MNRAS.453.1324B 453, 1324

    2015 doi

  5. [13]

    C.-J., Large M

    Bock D. C.-J., Large M. I., Sadler E. M., 1999, @doi [ ] 10.1086/300786 , http://adsabs.harvard.edu/abs/1999AJ....117.1578B 117, 1578

    1999 doi

  6. [14]

    Bonnarel F., et al., 2000, @doi [ ] 10.1051/aas:2000331 , https://ui.adsabs.harvard.edu/abs/2000A&AS..143...33B 143, 33

    2000 doi

  7. [15]

    A., Clayton G

    Cardelli J. A., Clayton G. C., Mathis J. S., 1989, @doi [ ] 10.1086/167900 , https://ui.adsabs.harvard.edu/\#abs/1989ApJ...345..245C 345, 245

    1989 doi

  8. [16]

    Churchwell E., et al., 2006, @doi [ ] 10.1086/507015 , http://adsabs.harvard.edu/abs/2006ApJ...649..759C 649, 759

    2006 doi

  9. [17]

    Churchwell E., et al., 2007, @doi [ ] 10.1086/521646 , http://adsabs.harvard.edu/abs/2007ApJ...670..428C 670, 428

    2007 doi

  10. [18]

    J., Cotton W

    Condon J. J., Cotton W. D., Greisen E. W., Yin Q. F., Perley R. A., Taylor G. B., Broderick J. J., 1998, @doi [ ] 10.1086/300337 , http://esoads.eso.org/abs/1998AJ....115.1693C 115, 1693

    1998 doi

  11. [19]

    Deharveng L., Zavagno A., Caplan J., 2005, @doi [ ] 10.1051/0004-6361:20041946 , http://adsabs.harvard.edu/abs/2005A

    2005 doi

  12. [20]

    Deharveng L., Zavagno A., Schuller F., Caplan J., Pomar \`e s M., De Breuck C., 2009, @doi [ ] 10.1051/0004-6361/200811337 , http://adsabs.harvard.edu/abs/2009A

    2009 doi

  13. [21]

    Deharveng L., et al., 2010, @doi [ ] 10.1051/0004-6361/201014422 , http://adsabs.harvard.edu/abs/2010A

    2010 doi

  14. [22]

    G., Lada C

    Elmegreen B. G., Lada C. J., 1977, @doi [ ] 10.1086/155302 , http://adsabs.harvard.edu/abs/1977ApJ...214..725E 214, 725

    1977 doi

  15. [23]

    E., Churchwell E., 2010, @doi [ ] 10.1088/0004-637X/713/1/592 , http://adsabs.harvard.edu/abs/2010ApJ...713..592E 713, 592

    Everett J. E., Churchwell E., 2010, @doi [ ] 10.1088/0004-637X/713/1/592 , http://adsabs.harvard.edu/abs/2010ApJ...713..592E 713, 592

    2010 doi

  16. [24]

    Figueira M., et al., 2017, @doi [ ] 10.1051/0004-6361/201629379 , http://esoads.eso.org/abs/2017A

    2017 doi

  17. [25]

    Figueira M., Bronfman L., Zavagno A., Louvet F., Lo N., Finger R., Rod \'o n J., 2018, @doi [ ] 10.1051/0004-6361/201832930 , http://adsabs.harvard.edu/abs/2018A

    2018 doi

  18. [26]

    Gaia Collaboration 2018, VizieR Online Data Catalog, https://ui.adsabs.harvard.edu/#abs/2018yCat.1345....0G p. I/345

    2018

  19. [27]

    F., Langer W

    Goldsmith P. F., Langer W. D., 1999, @doi [ ] 10.1086/307195 , http://adsabs.harvard.edu/abs/1999ApJ...517..209G 517, 209

    1999 doi

  20. [28]

    Hanaoka M., et al., 2019, @doi [ ] 10.1093/pasj/psy126 , http://adsabs.harvard.edu/abs/2019PASJ...71....6H 71, 6

    2019 doi

  21. [29]

    Hosokawa T., Inutsuka S.-i., 2006, @doi [ ] 10.1086/504789 , http://adsabs.harvard.edu/abs/2006ApJ...646..240H 646, 240

    2006 doi

  22. [30]

    Juvela M., Montillaud J., 2016, @doi [ ] 10.1051/0004-6361/201425112 , http://adsabs.harvard.edu/abs/2016A

    2016 doi

  23. [31]

    S., Wiebe D

    Kirsanova M. S., Wiebe D. S., Sobolev A. M., 2009, @doi [ ] 10.1134/S106377290907004X , http://adsabs.harvard.edu/abs/2009ARep...53..611K 53, 611

    2009 doi

  24. [32]

    L., 1984, , http://adsabs.harvard.edu/abs/1984A

    Leger A., Puget J. L., 1984, , http://adsabs.harvard.edu/abs/1984A

    1984

  25. [33]

    J., Gvaramadze V

    Mackey J., Haworth T. J., Gvaramadze V. V., Mohamed S., Langer N., Harries T. J., 2016, @doi [ ] 10.1051/0004-6361/201527569 , http://adsabs.harvard.edu/abs/2016A

    2016 doi

  26. [34]

    G., Shirley Y

    Mangum J. G., Shirley Y. L., 2015, @doi [ ] 10.1086/680323 , http://adsabs.harvard.edu/abs/2015PASP..127..266M 127, 266

    2015 doi

  27. [35]

    A., Whitworth A

    Marsh K. A., Whitworth A. P., 2019, @doi [ ] 10.1093/mnras/sty3186 , http://adsabs.harvard.edu/abs/2019MNRAS.483..352M 483, 352

    2019 doi

  28. [36]

    J., 2005, @doi [ ] 10.1051/0004-6361:20042386 , http://adsabs.harvard.edu/abs/2005A

    Martins F., Schaerer D., Hillier D. J., 2005, @doi [ ] 10.1051/0004-6361:20042386 , http://adsabs.harvard.edu/abs/2005A

    2005 doi

  29. [37]

    C., 2010, @doi [ ] 10.1051/0004-6361/200913158 , http://adsabs.harvard.edu/abs/2010A

    Martins F., Pomar \`e s M., Deharveng L., Zavagno A., Bouret J. C., 2010, @doi [ ] 10.1051/0004-6361/200913158 , http://adsabs.harvard.edu/abs/2010A

    2010 doi

  30. [38]

    M., Dickey J

    McClure-Griffiths N. M., Dickey J. M., Gaensler B. M., Green A. J., Haverkorn M., Strasser S., 2005, @doi [ ] 10.1086/430114 , http://adsabs.harvard.edu/abs/2005ApJS..158..178M 158, 178

    2005 doi

  31. [39]

    B., Verdolini S., Cox N

    Ochsendorf B. B., Verdolini S., Cox N. L. J., Bern \'e O., Kaper L., Tielens A. G. G. M., 2014, @doi [ ] 10.1051/0004-6361/201423545 , http://adsabs.harvard.edu/abs/2014A

    2014 doi

  32. [40]

    N., Shustov B

    Pavlyuchenkov Y. N., Shustov B. M., 2004, @doi [Astronomy Reports] 10.1134/1.1704676 , https://ui.adsabs.harvard.edu/\#abs/2004ARep...48..315P 48, 315

    2004 doi

  33. [41]

    Pavlyuchenkov Y., Wiebe D., Shustov B., Henning T., Launhardt R., Semenov D., 2008, @doi [ ] 10.1086/592564 , https://ui.adsabs.harvard.edu/\#abs/2008ApJ...689..335P 689, 335

    2008 doi

  34. [42]

    N., Kirsanova M

    Pavlyuchenkov Y. N., Kirsanova M. S., Wiebe D. S., 2013, @doi [ ] 10.1134/S1063772913070056 , http://adsabs.harvard.edu/abs/2013ARep...57..573P 57, 573

    2013 doi

  35. [43]

    C., Cant \'o J., Rodr \' guez L

    Raga A. C., Cant \'o J., Rodr \' guez L. F., 2012, , http://adsabs.harvard.edu/abs/2012RMxAA..48..149R 48, 149

    2012

  36. [44]

    Robitaille T., Bressert E., 2012, APLpy: Astronomical Plotting Library in Python , Astrophysics Source Code Library ( @eprint ascl 1208.017 )

    2012

  37. [45]

    P., Churchwell E., Benjamin R

    Robitaille T. P., Churchwell E., Benjamin R. A., Whitney B. A., Wood K., Babler B. L., Meade M. R., 2012, @doi [ ] 10.1051/0004-6361/201219073 , http://adsabs.harvard.edu/abs/2012A

    2012 doi

  38. [46]

    Russeil D., 2003, @doi [ ] 10.1051/0004-6361:20021504 , http://adsabs.harvard.edu/abs/2003A

    2003 doi

  39. [47]

    R., Deharveng L., Zavagno A., Anderson L

    Samal M. R., Deharveng L., Zavagno A., Anderson L. D., Molinari S., Russeil D., 2018, @doi [ ] 10.1051/0004-6361/201833015 , http://adsabs.harvard.edu/abs/2018A

    2018 doi

  40. [48]

    S \'a nchez-Cruces M., Castellanos-Ram \' rez A., Rosado M., Rodr \' guezGonz \'a lez A., Reyes-Iturbide J., 2018, , http://adsabs.harvard.edu/abs/2018RMxAA..54..375S 54, 375

    2018

  41. [49]

    Schuller F., et al., 2009, @doi [ ] 10.1051/0004-6361/200811568 , https://ui.adsabs.harvard.edu/\#abs/2009A&A...504..415S 504, 415

    2009 doi

  42. [50]

    Schuller F., et al., 2017, @doi [ ] 10.1051/0004-6361/201628933 , http://esoads.eso.org/abs/2017A

    2017 doi

  43. [51]

    Sellgren K., 1984, @doi [ ] 10.1086/161733 , http://adsabs.harvard.edu/abs/1984ApJ...277..623S 277, 623

    1984 doi

  44. [52]

    J., et al., 2012, @doi [ ] 10.1111/j.1365-2966.2012.20770.x , http://adsabs.harvard.edu/abs/2012MNRAS.424.2442S 424, 2442

    Simpson R. J., et al., 2012, @doi [ ] 10.1111/j.1365-2966.2012.20770.x , http://adsabs.harvard.edu/abs/2012MNRAS.424.2442S 424, 2442

    2012

  45. [53]

    New York Wiley-Interscience, 1978

    Spitzer L., 1978, Physical processes in the interstellar medium . New York Wiley-Interscience, 1978. 333 p., @doi 10.1002/9783527617722

    1978 doi

  46. [54]

    P., Wiebe D

    Topchieva A. P., Wiebe D. S., Kirsanova M. S., Krushinskii V. V., 2017, @doi [Astronomy Reports] 10.1134/S1063772917120083 , http://adsabs.harvard.edu/abs/2017ARep...61.1015T 61, 1015

    2017 doi

  47. [55]

    S., 2018a, @doi [Research in Astronomy and Astrophysics] 10.1088/1674-4527/18/8/91 , http://adsabs.harvard.edu/abs/2018RAA....18...91T 18, 091

    Topchieva A., Wiebe D., Kirsanova M. S., 2018a, @doi [Research in Astronomy and Astrophysics] 10.1088/1674-4527/18/8/91 , http://adsabs.harvard.edu/abs/2018RAA....18...91T 18, 091

    doi

  48. [56]

    P., Kirsanova M

    Topchieva A. P., Kirsanova M. S., Sobolev A. M., 2018b, @doi [Astronomy Reports] 10.1134/S1063772918110082 , http://adsabs.harvard.edu/abs/2018ARep...62..764T 62, 764

    doi

  49. [57]

    P., Akimkin V

    Topchieva A. P., Akimkin V. V., Smirnov-Pinchukov G. V., 2019, arXiv e-prints, https://ui.adsabs.harvard.edu/abs/2019arXiv190511077T p. arXiv:1905.11077

    2019 arXiv

  50. [58]

    Tremblin P., et al., 2014, @doi [ ] 10.1051/0004-6361/201322700 , http://adsabs.harvard.edu/abs/2014A

    2014 doi

  51. [59]

    Vassilev V., et al., 2008, @doi [ ] 10.1051/0004-6361:200810459 , http://adsabs.harvard.edu/abs/2008A

    2008 doi

  52. [60]

    P., Bisbas T

    Walch S., Whitworth A. P., Bisbas T. G., Hubber D. A., W \"u nsch R., 2015, @doi [ ] 10.1093/mnras/stv1427 , https://ui.adsabs.harvard.edu/\#abs/2015MNRAS.452.2794W 452, 2794

    2015 doi

  53. [61]

    Wenger M., et al., 2000, @doi [ ] 10.1051/aas:2000332 , http://adsabs.harvard.edu/abs/2000A

    2000 doi

  54. [62]

    L., 1999, @doi [Reports on Progress in Physics] 10.1088/0034-4885/62/2/002 , http://adsabs.harvard.edu/abs/1999RPPh...62..143W 62, 143

    Wilson T. L., 1999, @doi [Reports on Progress in Physics] 10.1088/0034-4885/62/2/002 , http://adsabs.harvard.edu/abs/1999RPPh...62..143W 62, 143

    1999 doi

  55. [63]

    Zavagno A., Pomar \`e s M., Deharveng L., Hosokawa T., Russeil D., Caplan J., 2007, @doi [ ] 10.1051/0004-6361:20077474 , http://adsabs.harvard.edu/abs/2007A

    2007 doi

  56. [64]

    Zavagno A., et al., 2010, @doi [ ] 10.1051/0004-6361/201014623 , http://adsabs.harvard.edu/abs/2010A

    2010 doi

  57. [65]

    van der Tak F. F. S., Black J. H., Sch \"o ier F. L., Jansen D. J., van Dishoeck E. F., 2007, , 468, 627

    2007

  58. [66]

    write newline

    " write newline "" before.all 'output.state := FUNCTION fin.entry write newline FUNCTION new.block output.state before.all = 'skip after.block 'output.state := if FUNCTION new.sentence output.state after.block = 'skip output.state before.all = 'skip after.sentence 'output.stat...

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.