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The deuterium fractionation of NH$_3$ in massive star-forming regions

T0 review · 4 major / 4 minor · reviewed 2026-08-12 · deepseek-v4-flash

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Pith's one-line read The paper shows that within massive star-forming regions, ammonia's deuterium fraction falls as temperature rises, with the deuteration peak displaced from the ammonia peak.

desk verdict A useful resolved survey of ammonia deuteration across 12 massive clumps, with plausible temperature trends that rest on an unverified beam-filling assumption. read the letter →

arxiv 2411.17121 v2 pith:YA6P3LEA submitted 2024-11-26 astro-ph.GA astro-ph.SR

Yuqiang Li , Junzhi Wang , Juan Li , Prathap Rayalacheruvu , Liton Majumdar , Yaoting Yan , Donghui Quan , Xing Lu
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Siqi Zheng
This is my paper · ORCID
classification astro-ph.GAastro-ph.SR
keywords deuteriumfractionationammoniaNH2Dmassivestar-formingregionsrotationtemperaturegas-grainchemicalmodelinterstellarchemistrymolecularclouds
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

The paper argues that the deuteration of ammonia in massive star-forming regions is regulated by local temperature and by the chemical evolution of the core. Using maps of ortho-NH$_2$D, NH$_3$(1,1), and NH$_3$(2,2) toward twelve late-stage regions, it finds that in seven sources the ammonia deuterium fraction $D_{\rm frac}(\mathrm{NH_3}) = N(\mathrm{NH_2D})/N(\mathrm{NH_3})$ decreases as the ammonia rotation temperature rises, and that in essentially every source the highest deuterium fraction is offset from the NH$_3$ peak. When all twelve sources are combined, the temperature trend weakens, which the paper explains as the result of source-to-source differences in density, cosmic-ray ionization rate, and evolutionary stage. A gas-grain chemical model that varies these parameters reproduces a general decline of $D_{\rm frac}(\mathrm{NH_3})$ with temperature while also showing why a single global trend should not be expected. The result matters because spatially resolved deuteration maps could become a practical thermometer and a tracer of core evolution in massive star formation.

What carries the argument

The central quantity is the deuterium fraction $D_{\rm frac}(\mathrm{NH_3}) = N(\mathrm{NH_2D})/N(\mathrm{NH_3})$, built from LTE column densities of the singly deuterated isotopologue NH$_2$D (in its ortho spin state) and of NH$_3$. The temperature axis is the ammonia rotation temperature $T_{\rm rot}(2,2;1,1)$ derived from the NH$_3$(2,2)/(1,1) line ratio, and the argument assumes this temperature also holds for NH$_2$D and that both molecules fill the 28.6-42.5 arcsecond beams. The chemical mechanism invoked is the standard deuterium chemistry in which H$_2$D$^+$ and CH$_2$D$^+$ donate deuterium to ammonia; because the H$_2$D$^+$/H$_3^+$ ratio falls sharply above roughly 15 K, and because CO released from grains at higher temperature consumes H$_3^+$, the NH$_2$D/NH$_3$ ratio declines as the gas warms. A gas-grain chemical model varying temperature (6-60 K), density ($10^4$-$10^7$ cm$^{-3}$), cosmic-ray ionization rate, and timescale (0.1-1 Myr) is used to show this decline while demonstrating that the other parameters introduce scatter large enough to hide the temperature trend in a mixed sample.

What would settle it

Observe one of the seven anticorrelating sources (for example G081.87+00.78) with an interferometer at sub-arcsecond resolution and detect a second NH$_2$D transition to measure its excitation temperature; if the deuterium fraction at the NH$_3$ peak is not lower than at the offset position once beam dilution and excitation are corrected, then the claimed anticorrelation and peak offset would be artifacts of the single-dish assumptions.

Watch

Extended reading notes

Core claim

Within a sample of twelve late-stage massive star-forming regions mapped in ortho-NH$_2$D $1_{11}^s-1_{01}^a$ at 85.9 GHz and NH$_3$(1,1)/(2,2) at 23.7 GHz, the paper reports that the deuterium fraction of ammonia anticorrelates with ammonia rotation temperature inside individual clouds. The anticorrelation is clear in seven sources (G031.28+00.06, G034.39+00.22, G035.19-00.74, G081.87+00.78, G109.87+02.11, G111.54+00.77, G121.29+00.65), with $D_{\rm frac}(\mathrm{NH_3})$ falling by factors of several as $T_{\rm rot}(2,2;1,1)$ climbs across its roughly 13-27 K range within a source. The paper also finds that the location of peak deuterium fractionation is offset from the NH$_3$ peak in almost all sources, most dramatically in G081.87+00.78 where the maximum $D_{\rm frac}=0.086\pm0.007$ lies $45''$ east and $9''$ north of the NH$_3$ peak. The offset is interpreted as the combined effect of higher temperatures near the NH$_3$ peak, gas-phase depletion of NH$_2$D as the core evolves, and CO released from grains suppressing the H$_2$D$^+$ pathway that forms NH$_2$D. The paper argues that the absence of a global anticorrelation across all twelve sources is expected because density, cosmic-ray ionization rate, and chemical timescale differ from source to source.

Load-bearing premise

The result depends on assuming that the NH$_2$D emission fills the telescope beam and that its excitation temperature equals the ammonia rotation temperature; if the NH$_2$D is actually colder or more compact than the beam, then the derived deuterium fraction near the NH$_3$ peak would be too low, which could create both the anticorrelation and the observed offsets by itself.

Editorial extensions

If this is right

  • Within a given massive star-forming clump, NH$_2$D/NH$_3$ can be used as a temperature indicator, with cooler pixels showing systematically higher deuterium fractionation.
  • Single-pointing surveys that pool many regions will systematically miss the temperature dependence, because variations in density, ionization rate, and age between clouds scatter the relation.
  • The spatial offset between the NH$_3$ peak and the NH$_2$D fractionation peak implies that the coldest, most deuterium-enriched gas is not the densest gas, and that core-scale chemical evolution separates the two.
  • If the model's chemistry is right, the anticorrelation should be strongest in regions where CO has been recently released from grains, and weakest in young, CO-poor cores.

Reading between the lines

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

  • An untested extension of the paper's logic is that the same anticorrelation should appear for other deuterated molecules such as DCO$^+$, DCN, or N$_2$D$^+$ when mapped at comparable angular resolution, since they share the H$_2$D$^+$-based deuteration chemistry.
  • The offset pattern implies a testable prediction for higher-resolution observations: the single-dish peak of $D_{\rm frac}$ is probably a blend of unresolved cold cores, each with its own temperature-deuteration gradient, rather than a single smooth ring.
  • A direct way to check the interpretation would be to observe a second NH$_2$D transition in one of the anticorrelating sources; measuring its excitation temperature independently would confirm whether the assumed $T_{\rm ex}=T_{\rm rot}$ is the source of the trend or a genuine chemical effect.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

4 major / 4 minor

Summary. Using IRAM 30 m maps of ortho-NH2D 1_11^s-1_01^a together with GBT and Effelsberg maps of NH3(1,1) and NH3(2,2), the paper derives the deuterium fractionation Dfrac(NH3) at roughly 30-42 arcsecond resolution in 12 late-stage massive star-forming regions. The authors report a decreasing Dfrac(NH3) with increasing rotational temperature within seven individual sources, no clear global trend when all 12 sources are combined, and a spatial offset between the NH3 peak and the position of highest Dfrac(NH3). They interpret these results with gas-grain chemical model calculations over a grid of temperature, density, cosmic-ray ionization rate, and time, concluding that temperature and environmental evolution drive the NH2D distribution.

Significance. If the central claims survive scrutiny, this paper provides a comparatively large single-dish mapping sample connecting NH2D/NH3 to temperature within individual regions, extending earlier interferometric case studies. The authors make a useful effort to tabulate per-position rotational temperatures, column densities, and Dfrac values, and they use an established public chemical network with a documented parameter grid rather than fitting the model to the observed Dfrac values. They also state their key assumptions openly, including the unity beam filling factor and the assumed equality between Trot and Tex(NH2D). The main risk is that the conversion from observed line intensities to the physical ratio N(NH2D)/N(NH3), which underlies every conclusion, depends on assumptions about source size and excitation that are not yet quantitatively bounded.

major comments (4)
  1. [§2.3 and §3.2] The assumption that the beam filling factor is unity for all lines (Section 2.3) is load-bearing because NH2D and NH3 were observed at different native resolutions and no source-size measurement is presented. If NH2D emission is more compact than NH3 emission, particularly near the NH3 peak, the NH2D main-beam temperature is diluted relative to NH3, and the derived Dfrac(NH3) would be artificially low at the peak. This mechanism alone could generate both the within-source anticorrelation in Figure 4 and the spatial offset between Dfrac and NH3 peaks in Figures E1/E2. The statement in Section 3.2 that the Tex(NH2D)=Trot assumption gives at most a 15% error for Tex>10 K does not cover filling-factor dilution or subthermal excitation below 10 K, both of which can be substantially larger. Please quantify the sensitivity of the results to a range of plausible source-size and excitation profiles, or explicitly restrict the claims to quantities that are robust under such variations.
  2. [Table 3, Table C1, §3.4.3] The Dfrac values for G031.28+00.06 are internally inconsistent by roughly an order of magnitude. Table C1 lists Dfrac(NH3)×100 in the range 0.062-0.13, while Section 3.4.3 states a range from 0.009±0.001 to 0.013±0.002. Computing the ratio from the tabulated N(NH3) and N(NH2D) columns in Table C1, for example 0.69×10^15 cm^-2 and 0.81×10^13 cm^-2 in the first row, gives Dfrac≈1.17×10^-2, i.e., about 1.17%, not 0.07%. Because G031.28+00.06 is one of the seven sources used to support the anticorrelation claim, the tables and text must be reconciled before the statistical conclusions can be accepted.
  3. [§4.1, Table 3] The classification of the seven sources as showing a clear anticorrelation between Dfrac(NH3) and Trot(2,2;1,1) is not supported by any quantitative measure. No correlation coefficient, significance test, or explicit definition of a 'clear' trend is given, and some sources assigned to the 'no' group have comparable dynamic ranges, such as G015.03-00.67 with Dfrac varying from 0.005 to 0.012 over Trot 19.5-24.8 K and G081.75+00.59 with Dfrac varying from 0.022 to 0.068. Additionally, the rows in Table C1 are averages over 3×3 or 2×2 pixel boxes, so adjacent rows are not independent samples; the effective number of independent data points is smaller than the number of rows. Please provide a correlation statistic or a pre-specified criterion and account for spatial autocorrelation.
  4. [Abstract; §3.3; §4.4; §5] The paper's offset claim is stated in inconsistent strengths. The abstract says the region of highest Dfrac is 'offset from the NH3 peak in each source'; Section 3.3 states this for the six sources in which the NH3 and NH2D morphologies differ; Section 4.4 notes that in G075.76+00.33 the highest Dfrac and the highest rotation temperature occur at the same position; and Conclusion item 2 restricts the offset to the seven sources with different morphologies. The abstract and the body need to agree on the qualified version of this claim.
minor comments (4)
  1. [§3.4.7] The uncertainty on the lower end of the Dfrac range is printed as '0.018 ±0.2'; this is presumably a typo for ±0.002 and should be corrected.
  2. [Figure 8 caption] The caption says 'The cosmic-ray ionization rate is set to nH2=10^6 cm^-3'; this should read 'The proton density is set to nH=10^6 cm^-3'.
  3. [§2.3] The text states that the nine GBT sources were regridded to a beam size of 30 arcsec, while Section 2.1.2 gives the GBT beam as 31.8 arcsec at 23 GHz; please clarify whether a 30 arcsec Gaussian beam or the actual 31.8 arcsec beam was adopted.
  4. [Table 3] The column heading 'Dfrac(NH3)×100' is used inconsistently with the values in Table C1 and with the body text; define the unit once and apply it uniformly across all tables and text.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: Dfrac values come from standard LTE formulae and independent chemical simulations, not from fitting the target trend.

full rationale

The paper's central claim is an observed anticorrelation between Dfrac(NH3) and Trot within individual sources. Dfrac(NH3) is obtained from measured velocity-integrated intensities of NH2D and NH3 using the standard LTE column-density formula (Eq. 1), with stated assumptions: beam filling factor unity, NH2D optically thin, ortho/para ratio 3, and Tex(NH2D)=Trot(NH3). These assumptions could bias the derived values, but they are not fitted parameters tuned to reproduce the anticorrelation, and the LTE correction factors do not by construction force a decreasing Dfrac-versus-Trot trend over the 13-27 K range; the trend instead reflects the observed line-intensity ratios. The chemical model is the published DNAUTILUS gas-grain code based on the KIDA network, run over a grid of temperature, density, cosmic-ray ionization rate, and timescale; its predicted Dfrac(T) is not fitted to the observed Dfrac values. Self-citations to Li et al. (2024) for the NH2D maps and to Majumdar et al. (2017) for the model are uses of observational data and a published code, not unverified theorems or ansatze imported to forbid alternatives. The acknowledged assumptions about filling factor and excitation temperature are systematic-uncertainty concerns, not circular reductions. The derivation chain is therefore self-contained against external data and independent modeling, and no load-bearing step reduces to its own inputs.

Assumptions & free parameters 2 free parameters · 7 assumptions · 0 invented entities

The observational Dfrac values rest on a chain of LTE assumptions rather than on measured excitation temperatures. The chemical model is a parameter exploration, not a fit, so no model parameters were tuned to the observed Dfrac values; however, the model conclusions inherit the KIDA network's uncertainties. No new particles, forces, or physical entities are introduced.

free parameters (2)
  • ortho-to-para ratio of NH2D = 3 (assumed, from Tiné et al. 2000)
    Section 3.2: N(NH2D) is derived from the ortho line and multiplied by this ratio to obtain total NH2D. Absolute Dfrac values scale with this choice, though relative spatial trends do not.
  • beam filling factor = 1 (assumed)
    Section 2.3: all lines are treated as filling the beam. If NH2D emission is clumpy or more compact than the beam, column densities are underestimated, most severely at the NH3 peak, which could create artificial offsets.
assumptions (7)
  • domain assumption LTE and a single excitation temperature describe the NH3 and NH2D level populations
    Equation 1 (Section 3.2) converts integrated intensities to column densities using LTE partition functions. Subthermal excitation would bias N and Dfrac.
  • domain assumption Tex(NH2D) equals Trot(2,2;1,1) for the ortho-NH2D 1_11-1_01 line
    Section 3.2: only one NH2D transition is observed, so Tex cannot be measured. The authors bound the error at 15% for Tex above 10 K, but larger deviations are possible in cold, low-density gas.
  • domain assumption The ortho-NH2D line is optically thin
    Section 3.2: no opacity correction is applied for NH2D. Significant optical depth would make N(NH2D) a lower limit and could flatten the derived anticorrelation.
  • domain assumption Beam filling factor is unity for all lines at the smoothed resolutions
    Section 2.3: unresolved structure, especially in NH2D, is ignored. Differential clumpiness between NH2D and NH3 can create artificial spatial trends.
  • domain assumption NH3 and NH2D emission trace the same gas, and the NH3 peak marks the core center
    Sections 3.3 and 4.4: the Dfrac and core-offset interpretation assume co-spatial emitting regions. If NH2D traces a different gas component, the physical picture changes.
  • domain assumption The KIDA gas-grain network and the DNAUTILUS two-phase/three-phase treatment are reliable for NH2D/NH3 chemistry
    Section 4.2: model predictions inherit all reaction-rate uncertainties, the assumed initial abundances, and the neglect of spin-state chemistry for deuterated species.
  • domain assumption Rotational temperature from NH3(2,2)/(1,1) is a good kinetic temperature proxy in these regions
    Sections 3.2 and 4.4: Trot is interpreted as the gas temperature driving the chemistry, though it can differ from kinetic temperature in low-density gas.

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Cite this review

Pith. "Pith review of The deuterium fractionation of NH$_3$ in massive star-forming regions." pith.science (2026). https://pith.science/paper/YA6P3LEA

@misc{pith2026241117121,
  author       = {Pith},
  title        = {Pith review of: The deuterium fractionation of NH$_3$ in massive star-forming regions},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/YA6P3LEA}},
  note         = {Machine review of arXiv:2411.17121}
}
abstract

Deuteration is sensitive to environmental conditions in star-forming regions. To investigate NH$_2$D chemistry, we compared the spatial distribution of ortho-NH$_2$D $1_{11}^s-1_{01}^a$, NH$_3$(1,1) and NH$_3$(2,2) in 12 late-stage massive star-forming regions. By averaging several pixels along the spatial slices of ortho-NH$_2$D $1_{11}^s-1_{01}^a$, we obtained the deuterium fractionation of NH$_3$. In seven targets, the deuterium fractionation of NH$_3$ shows a decreasing trend with increasing rotational temperature. This trend is less clear in the remaining five sources, likely due to limited spatial resolution. However, when considering all 12 sources together, the anticorrelation between NH$_3$ deuterium fractionation and rotational temperature becomes less significant, suggesting that other physical parameters may influence the fractionation. Additionally, we found that the region of highest deuterium fractionation of NH$_3$ is offset from the NH$_3$ peak in each source, likely because the temperature is higher near the NH$_3$ peaks and NH$_2$D may be depleted from the gas phase as the molecular cloud core evolves, as well as the increased release of CO from grains into the gas phase.

Figures

Figures reproduced from arXiv: 2411.17121 by the authors.

Figure 1
Figure 1. (a) The velocity-integrated intensity of the ortho-NH2D 1s 11 − 1 a 01 contour (red contour) overlaid on the NH3(1,1) main group velocity-integrated intensity image (gray scale and black contour) in G035.19-00.74. The contour levels start at 5σ in steps of 5σ for ortho-NH2D 1s 11 − 1 a 01, while the contour levels start at 90σ in steps of 54σ for the NH3(1,1) main group. The gray scale starts at 3σ. (b) Ortho-NH2D 1… view at source ↗
Figure 2
Figure 2. The pixels in the box are the average area in G035.19-00.74. The order of the region numbers is the order in Table C1. 0 10 20 30 40 50 60 70 distance( 00) 2 × 10 2 3 × 10 2 4 × 10 2 Dfrac(N H3) G035.19-00.74 NH3 peak: (0 00 ,0 00) p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 [PITH_FULL_IMAGE:figures/full_fig_p016_2.png] view at source ↗
Figure 3
Figure 3. The relationship between deuterium fractionation of NH3 and distance of NH3 peak in G035.19-00.74 [PITH_FULL_IMAGE:figures/full_fig_p016_3.png] view at source ↗
Figures from the paper (6 more)
Figure 4
Figure 4. Figure 4: The deuterium fractionation of ammonia compared with the ammonia rotation temperature. Each source is repre￾sented by a different color. (a) Dfrac(NH3) compared with Trot(2,2;1,1) over the whole sample. (b) Dfrac(NH3) compared with Trot(2,2;1,1) for seven sources that …
Figure 5
Figure 5. Figure 5: Deuterium fractionation of NH3 as a function of temperature simulated by the gas-grain chemical model. The timescales for the red, blue and green lines are 0.1, 0.5 and 1 Myr, respectively [PITH_FULL_IMAGE:figures/full_fig_p017_5.png]
Figure 6
Figure 6. Figure 6: Deuterium fractionation of NH3 as a function of timescale simulated by the gas-grain chemical model. The timescales for the red, blue, green and yellow lines are 10, 20, 30 and 60 K, respectively. 10 20 30 40 50 60 Temperature (K) 10−3 10−2 10−1 Dfrac(NH 3) (a) 0.1 Myr…
Figure 7
Figure 7. Figure 7: Deuterium fractionation of NH3 as a function of temperature for different densities simulated by the gas-grain chemical model. The density of H2 for the red, blue, green and yellow lines is 104 , 105 , 106 and 107 cm−3 , respectively. The timescales for the left, middl…
Figure 8
Figure 8. Figure 8: Deuterium fractionation of NH3 as a function of temperature for different cosmic-ray ionization rates simulated by the gas-grain chemical model. The cosmic-ray ionization rate for the red, blue, green, yellow and violet lines is 3×10−18 , 1.5×10−17, 3×10−17, 6×10−17 an…
Figure 9
Figure 9. Figure 9: The relationship between rotation temperature of NH3 and distance of NH3 peak in G035.19-00.74. The red marker is the position with the highest deuterium fractionation of NH3 [PITH_FULL_IMAGE:figures/full_fig_p019_9.png]

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Works this paper leans on

96 extracted references · 27 canonical work pages

  1. [1]

    , " * write output.state after.block = add.period write newline

    ENTRY address archivePrefix author booktitle chapter doi edition editor eprint howpublished institution journal key month number organization pages publisher school series title misctitle type volume year version url label extra.label sort.label short.list INTEGERS output.state before.all mid.sentence after.sentence after.block FUNCTION init.state.consts ...

  2. [2]

    write newline

    " write newline "" before.all 'output.state := FUNCTION format.url url empty "" new.block "" url * "" * if FUNCTION format.eprint eprint empty "" archivePrefix empty "" archivePrefix "arXiv" = new.block " " eprint * " " * new.block " " eprint * " " * if if if FUNCTION format.doi doi empty "" " " doi * " " * if FUNCTION format.pid doi empty eprint empty ur...

  3. [3]

    - [1] #1 = = ^ ^ ^ .\!\!^ d .\!\!^ h .\!\!^ m .\!\!^ s .\!\!^ @mss

    thebibliography [1] 20pt to REFERENCES 6pt =0pt -12pt 10pt plus 3pt =0pt =0pt =1pt plus 1pt =0pt =0pt -12pt =13pt plus 1pt =20pt =13pt plus 1pt \@M =10000 =-1.0em =0pt =0pt 0pt =0pt =1.0em @enumiv\@empty 10000 10000 `\.\@m \@noitemerr \@latex@warning Empty `thebibliography' environment \@ifnextchar \@reference \@latexerr Missing key on reference command E...

    2021

  4. [4]

    2022, , 659, A77, 10.1051/0004-6361/202142689

    Beuther , H., Schneider , N., Simon , R., et al. 2022, , 659, A77, 10.1051/0004-6361/202142689

    doi:10.1051/0004-6361/202142689 2022

  5. [5]

    2010, , 517, L6, 10.1051/0004-6361/201014866

    Busquet , G., Palau , A., Estalella , R., et al. 2010, , 517, L6, 10.1051/0004-6361/201014866

    work page doi:10.1051/0004-6361/201014866 2010

  6. [6]

    2002, , 50, 1133, 10.1016/S0032-0633(02)00074-0

    Caselli , P. 2002, , 50, 1133, 10.1016/S0032-0633(02)00074-0

    doi:10.1016/s0032-0633(02)00074-0 2002

  7. [7]

    2012, , 20, 56, 10.1007/s00159-012-0056-x

    Caselli , P., & Ceccarelli , C. 2012, , 20, 56, 10.1007/s00159-012-0056-x

    doi:10.1007/s00159-012-0056-x 2012

  8. [8]

    2008, , 492, 703, 10.1051/0004-6361:20079009

    Caselli , P., Vastel , C., Ceccarelli , C., et al. 2008, , 492, 703, 10.1051/0004-6361:20079009

    doi:10.1051/0004-6361:20079009 2008

Show all 96 references
  1. [9]

    M., Terzieva , R., & Herbst , E

    Caselli , P., Walmsley , C. M., Terzieva , R., & Herbst , E. 1998, , 499, 234, 10.1086/305624

    1998 doi

  2. [10]

    2014, in Protostars and Planets VI, ed

    Ceccarelli , C., Caselli , P., Bockel \'e e-Morvan , D., et al. 2014, in Protostars and Planets VI, ed. H. Beuther , R. S. Klessen , C. P. Dullemond , & T. Henning , 859--882, 10.2458/azu_uapress_9780816531240-ch037

    2014 doi

  3. [11]

    B., Wyrowski , F., Menten , K

    Christensen , I. B., Wyrowski , F., Menten , K. M., Beuther , H., & Cascade Team . 2023, in Physics and Chemistry of Star Formation: The Dynamical ISM Across Time and Spatial Scales, 253

    2023

  4. [12]

    M., et al

    Crapsi , A., Caselli , P., Walmsley , C. M., et al. 2005, , 619, 379, 10.1086/426472

    2005 doi

  5. [13]

    C., & Tafalla , M

    Crapsi , A., Caselli , P., Walmsley , M. C., & Tafalla , M. 2007, , 470, 221, 10.1051/0004-6361:20077613

    2007 doi

  6. [14]

    Dent , W. R. F., Little , L. T., & White , G. J. 1984, , 210, 173, 10.1093/mnras/210.1.173

    1984 doi

  7. [15]

    R., Dickel , H

    Dickel , J. R., Dickel , H. R., & Wilson , W. J. 1978, , 223, 840, 10.1086/156317

    1978 doi

  8. [16]

    H., Stutzki , J., & Wiedner , M

    Emprechtinger , M., Caselli , P., Volgenau , N. H., Stutzki , J., & Wiedner , M. C. 2009, , 493, 89, 10.1051/0004-6361:200810324

    2009 doi

  9. [17]

    A., Di Francesco , J., et al

    Fallscheer , C., Reid , M. A., Di Francesco , J., et al. 2013, , 773, 102, 10.1088/0004-637X/773/2/102

    2013 doi

  10. [18]

    L., Claussen , M

    Fey , A. L., Claussen , M. J., Gaume , R. A., Nedoluha , G. E., & Johnston , K. J. 1992, , 103, 234, 10.1086/116056

    1992 doi

  11. [19]

    2015, , 575, A87, 10.1051/0004-6361/201424753

    Fontani , F., Busquet , G., Palau , A., et al. 2015, , 575, A87, 10.1051/0004-6361/201424753

    2015 doi

  12. [20]

    2011, , 529, L7, 10.1051/0004-6361/201116631

    Fontani , F., Palau , A., Caselli , P., et al. 2011, , 529, L7, 10.1051/0004-6361/201116631

    2011 doi

  13. [21]

    G., Hoare , M

    Gibb , A. G., Hoare , M. G., Little , L. T., & Wright , M. C. H. 2003, , 339, 1011, 10.1046/j.1365-8711.2003.06251.x

    2003

  14. [22]

    F., & Langer , W

    Goldsmith , P. F., & Langer , W. D. 1999, , 517, 209, 10.1086/307195

    1999 doi

  15. [23]

    M., Joy , M., Lester , D

    Harvey , P. M., Joy , M., Lester , D. F., & Wilking , B. A. 1986, , 300, 737, 10.1086/163848

    1986 doi

  16. [24]

    2012, , 543, L3, 10.1051/0004-6361/201219429

    Hennemann , M., Motte , F., Schneider , N., et al. 2012, , 543, L3, 10.1051/0004-6361/201219429

    2012 doi

  17. [25]

    1982, , 111, 76

    Herbst , E. 1982, , 111, 76

    1982

  18. [26]

    Ho , P. T. P., & Townes , C. H. 1983, , 21, 239, 10.1146/annurev.aa.21.090183.001323

    1983

  19. [27]

    2018, , 237, 27, 10.3847/1538-4365/aacf94

    Hogge , T., Jackson , J., Stephens , I., et al. 2018, , 237, 27, 10.3847/1538-4365/aacf94

    2018 doi

  20. [28]

    C., Goodson , M

    Hsu , C.-J., Tan , J. C., Goodson , M. D., et al. 2021, , 502, 1104, 10.1093/mnras/staa4031

    2021 doi

  21. [29]

    A., & Wouterloot , J

    Hughes , V. A., & Wouterloot , J. G. A. 1984, , 276, 204, 10.1086/161603

    1984 doi

  22. [30]

    S., J rgensen , J

    Jensen , S. S., J rgensen , J. K., Kristensen , L. E., et al. 2021, , 650, A172, 10.1051/0004-6361/202140560

    2021 doi

  23. [31]

    B., Girart , J

    Ju \'a rez , C., Liu , H. B., Girart , J. M., et al. 2019, , 621, A140, 10.1051/0004-6361/201834173

    2019 doi

  24. [32]

    2019, , 884, 4, 10.3847/1538-4357/ab3e76

    Keown , J., Di Francesco , J., Rosolowsky , E., et al. 2019, , 884, 4, 10.3847/1538-4357/ab3e76

    2019 doi

  25. [33]

    2009, , 694, 1056, 10.1088/0004-637X/694/2/1056

    Kirby , L. 2009, , 694, 1056, 10.1088/0004-637X/694/2/1056

    2009 doi

  26. [34]

    Kurtz , S., Cesaroni , R., Churchwell , E., Hofner , P., & Walmsley , C. M. 2000, in Protostars and Planets IV, ed. V. Mannings , A. P. Boss , & S. S. Russell , 299--326

    2000

  27. [35]

    Lada , C. J. 1976, , 32, 603, 10.1086/190409

    1976 doi

  28. [36]

    A., Bally , J., & Stark , A

    Lada , E. A., Bally , J., & Stark , A. A. 1991, , 368, 432, 10.1086/169708

    1991 doi

  29. [37]

    2017, , 466, 248, 10.1093/mnras/stw3076

    Li , S., Wang , J., Zhang , Z.-Y., et al. 2017, , 466, 248, 10.1093/mnras/stw3076

    2017 doi

  30. [38]

    2021, , 912, L7, 10.3847/2041-8213/abf64f

    Li , S., Lu , X., Zhang , Q., et al. 2021, , 912, L7, 10.3847/2041-8213/abf64f

    2021 doi

  31. [39]

    2024, , 527, 5049, 10.1093/mnras/stad3480

    Li , Y., Wang , J., Li , J., et al. 2024, , 527, 5049, 10.1093/mnras/stad3480

    2024 doi

  32. [40]

    L., Diplas , A., Wood , B

    Linsky , J. L., Diplas , A., Wood , B. E., et al. 1995, , 451, 335, 10.1086/176223

    1995 doi

  33. [41]

    C., Gerin , M., Phillips , T

    Lis , D. C., Gerin , M., Phillips , T. G., & Motte , F. 2002, , 569, 322, 10.1086/339232

    2002 doi

  34. [42]

    T., Dent , W

    Little , L. T., Dent , W. R. F., Heaton , B., Davies , S. R., & White , G. J. 1985, , 217, 227, 10.1093/mnras/217.2.227

    1985 doi

  35. [43]

    2015, , 805, 171, 10.1088/0004-637X/805/2/171

    Lu , X., Zhang , Q., Wang , K., & Gu , Q. 2015, , 805, 171, 10.1088/0004-637X/805/2/171

    2015 doi

  36. [44]

    D., Balser , D

    Luisi , M., Anderson , L. D., Balser , D. S., Bania , T. M., & Wenger , T. V. 2016, , 824, 125, 10.3847/0004-637X/824/2/125

    2016 doi

  37. [45]

    2017, , 466, 4470, 10.1093/mnras/stw3360

    Majumdar , L., Gratier , P., Ruaud , M., et al. 2017, , 466, 4470, 10.1093/mnras/stw3360

    2017 doi

  38. [46]

    G., Wootten , A., & Mundy , L

    Mangum , J. G., Wootten , A., & Mundy , L. G. 1991, , 378, 576, 10.1086/170459

    1991 doi

  39. [47]

    1992, , 388, 467, 10.1086/171167

    ---. 1992, , 388, 467, 10.1086/171167

    1992 doi

  40. [48]

    E., Goss , W

    Matthews , H. E., Goss , W. M., Winnberg , A., & Habing , H. J. 1973, , 29, 309

    1973

  41. [49]

    P., Rodriguez , L

    Miralles , M. P., Rodriguez , L. F., & Scalise , E. 1994, , 92, 173, 10.1086/191965

    1994 doi

  42. [50]

    2007, , 476, 1243, 10.1051/0004-6361:20077843

    Motte , F., Bontemps , S., Schilke , P., et al. 2007, , 476, 1243, 10.1051/0004-6361:20077843

    2007 doi

  43. [51]

    u ller , H. S. P., Schl \

    M \"u ller , H. S. P., Schl \"o der , F., Stutzki , J., & Winnewisser , G. 2005, Journal of Molecular Structure, 742, 215, 10.1016/j.molstruc.2005.01.027

    2005 doi

  44. [52]

    M \"u ller , H. S. P., Thorwirth , S., Roth , D. A., & Winnewisser , G. 2001, , 370, L49, 10.1051/0004-6361:20010367

    2001 doi

  45. [53]

    L., Crockett , N

    Neill , J. L., Crockett , N. R., Bergin , E. A., Pearson , J. C., & Xu , L.-H. 2013, , 777, 85, 10.1088/0004-637X/777/2/85

    2013 doi

  46. [54]

    2011, , 529, A41, 10.1051/0004-6361/201016271

    Nguyen Luong , Q., Motte , F., Schuller , F., et al. 2011, , 529, A41, 10.1051/0004-6361/201016271

    2011 doi

  47. [55]

    I., Cleeves , L

    \"O berg , K. I., Cleeves , L. I., Bergner , J. B., et al. 2021, , 161, 38, 10.3847/1538-3881/abc74d

    2021 doi

  48. [56]

    M., H \'e brard , G., Howk , J

    Oliveira , C. M., H \'e brard , G., Howk , J. C., et al. 2003, , 587, 235, 10.1086/368019

    2003 doi

  49. [57]

    Pagani , L., Salez , M., & Wannier , P. G. 1992, , 258, 479

    1992

  50. [58]

    G., Zinchenko , I

    Pazukhin , A. G., Zinchenko , I. I., Trofimova , E. A., Henkel , C., & Semenov , D. A. 2023, , 526, 3673, 10.1093/mnras/stad2976

    2023 doi

  51. [59]

    Persi , P., Tapia , M., & Smith , H. A. 2006, , 445, 971, 10.1051/0004-6361:20053251

    2006 doi

  52. [60]

    2011, , 530, A118, 10.1051/0004-6361/201015899

    Pillai , T., Kauffmann , J., Wyrowski , F., et al. 2011, , 530, A118, 10.1051/0004-6361/201015899

    2011 doi

  53. [61]

    G., & Thompson , M

    Pillai , T., Wyrowski , F., Hatchell , J., Gibb , A. G., & Thompson , M. A. 2007, , 467, 207, 10.1051/0004-6361:20065682

    2007 doi

  54. [62]

    S., Churchwell , E., Bieging , J

    Povich , M. S., Churchwell , E., Bieging , J. H., et al. 2009, , 696, 1278, 10.1088/0004-637X/696/2/1278

    2009 doi

  55. [63]

    M., Jackson , J

    Rathborne , J. M., Jackson , J. M., & Simon , R. 2006, , 641, 389, 10.1086/500423

    2006 doi

  56. [64]

    2014, , 440, 3557, 10.1093/mnras/stu462

    Reboussin , L., Wakelam , V., Guilloteau , S., & Hersant , F. 2014, , 440, 3557, 10.1093/mnras/stu462

    2014 doi

  57. [65]

    A., & Wilson , C

    Reid , M. A., & Wilson , C. D. 2005, , 625, 891, 10.1086/429790

    2005 doi

  58. [66]

    Z., Liu , T., Wu , Y., & Li , L

    Ren , J. Z., Liu , T., Wu , Y., & Li , L. 2011, , 415, L49, 10.1111/j.1745-3933.2011.01076.x

    2011

  59. [67]

    D., & Charnley , S

    Rodgers , S. D., & Charnley , S. B. 2001, , 553, 613, 10.1086/320987

    2001 doi

  60. [68]

    N., Zuckerman , B., & Kuiper , T

    Rodriguez Kuiper , E. N., Zuckerman , B., & Kuiper , T. B. H. 1978, , 219, L49, 10.1086/182604

    1978 doi

  61. [69]

    A., Goss , W

    Roshi , D. A., Goss , W. M., Anantharamaiah , K. R., & Jeyakumar , S. 2005, , 626, 253, 10.1086/429747

    2005 doi

  62. [70]

    C., van der Tak , F

    Roueff , E., Lis , D. C., van der Tak , F. F. S., Gerin , M., & Goldsmith , P. F. 2005, , 438, 585, 10.1051/0004-6361:20052724

    2005 doi

  63. [71]

    C., Hickson , K

    Ruaud , M., Loison , J. C., Hickson , K. M., et al. 2015, , 447, 4004, 10.1093/mnras/stu2709

    2015 doi

  64. [72]

    Rygl , K. L. J., Brunthaler , A., Reid , M. J., et al. 2010, , 511, A2, 10.1051/0004-6361/200913135

    2010 doi

  65. [73]

    Rygl , K. L. J., Goedhart , S., Polychroni , D., et al. 2014, , 440, 427, 10.1093/mnras/stu300

    2014 doi

  66. [74]

    2000, , 535, 227, 10.1086/308818

    Saito , S., Ozeki , H., Ohishi , M., & Yamamoto , S. 2000, , 535, 227, 10.1086/308818

    2000 doi

  67. [75]

    2012, , 747, 140, 10.1088/0004-637X/747/2/140

    Sakai , T., Sakai , N., Furuya , K., et al. 2012, , 747, 140, 10.1088/0004-637X/747/2/140

    2012 doi

  68. [76]

    K., Ojha , D

    Sharma , S., Pandey , A. K., Ojha , D. K., et al. 2017, , 467, 2943, 10.1093/mnras/stx014

    2017 doi

  69. [77]

    S., Kurtz , S

    Shepherd , D. S., Kurtz , S. E., & Testi , L. 2004, , 601, 952, 10.1086/380633

    2004 doi

  70. [78]

    S., Testi , L., & Stark , D

    Shepherd , D. S., Testi , L., & Stark , D. P. 2003, , 584, 882, 10.1086/345743

    2003 doi

  71. [79]

    2013, , 554, A92, 10.1051/0004-6361/201220922

    Sipil \"a , O., Caselli , P., & Harju , J. 2013, , 554, A92, 10.1051/0004-6361/201220922

    2013 doi

  72. [80]

    2015 a , , 578, A55, 10.1051/0004-6361/201424364

    ---. 2015 a , , 578, A55, 10.1051/0004-6361/201424364

    2015 doi

  73. [81]

    2015 b , , 581, A122, 10.1051/0004-6361/201526468

    Sipil \"a , O., Harju , J., Caselli , P., & Schlemmer , S. 2015 b , , 581, A122, 10.1051/0004-6361/201526468

    2015 doi

  74. [82]

    2000, , 356, 1039

    Tin \'e , S., Roueff , E., Falgarone , E., Gerin , M., & Pineau des For \^e ts , G. 2000, , 356, 1039

    2000

  75. [83]

    Turner , B. E. 1990, , 362, L29, 10.1086/185840

    1990 doi

  76. [84]

    E., Zuckerman , B., Morris , M., & Palmer , P

    Turner , B. E., Zuckerman , B., Morris , M., & Palmer , P. 1978, , 219, L43, 10.1086/182603

    1978 doi

  77. [85]

    2000, , 537, 221, 10.1086/308992

    Ungerechts , H., Umbanhowar , P., & Thaddeus , P. 2000, , 537, 221, 10.1086/308992

    2000 doi

  78. [86]

    S., Figura , C

    Urquhart , J. S., Figura , C. C., Moore , T. J. T., et al. 2015, , 452, 4029, 10.1093/mnras/stv1514

    2015 doi

  79. [87]

    van der Tak , F. F. S., & van Dishoeck , E. F. 2000, , 358, L79, 10.48550/arXiv.astro-ph/0006246

    2000 doi arXiv

  80. [88]

    F., & Blake , G

    van Dishoeck , E. F., & Blake , G. A. 1998, , 36, 317, 10.1146/annurev.astro.36.1.317

    1998 doi

  81. [89]

    C., Hickson , K

    Wakelam , V., Loison , J. C., Hickson , K. M., & Ruaud , M. 2015 a , , 453, L48, 10.1093/mnrasl/slv097

    2015 doi

  82. [90]

    C., Herbst , E., et al

    Wakelam , V., Loison , J. C., Herbst , E., et al. 2015 b , , 217, 20, 10.1088/0067-0049/217/2/20

    2015 doi

  83. [91]

    J., Burton , M

    Walsh , A. J., Burton , M. G., Hyland , A. R., & Robinson , G. 1998, , 301, 640, 10.1046/j.1365-8711.1998.02014.x

    1998

  84. [92]

    M., et al

    Wienen , M., Wyrowski , F., Walmsley , C. M., et al. 2021, , 649, A21, 10.1051/0004-6361/201731208

    2021 doi

  85. [93]

    Wood , D. O. S., & Churchwell , E. 1989, , 69, 831, 10.1086/191329

    1989 doi

  86. [94]

    J., et al

    Xu , Y., Moscadelli , L., Reid , M. J., et al. 2011, , 733, 25, 10.1088/0004-637X/733/1/25

    2011 doi

  87. [95]

    2020, , 638, A105, 10.1051/0004-6361/201936118

    Zhang , C.-P., Li , G.-X., Pillai , T., et al. 2020, , 638, A105, 10.1051/0004-6361/201936118

    2020 doi

  88. [96]

    2023, , 522, 503, 10.1093/mnras/stad996

    Zhu , F.-Y., Wang , J., Yan , Y., Zhu , Q.-F., & Li , J. 2023, , 522, 503, 10.1093/mnras/stad996

    2023 doi

Pith tools

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