Water in low-mass star-forming regions with Herschel (WISH-LM) - High-velocity H2O bullets in L1448-MM observed with HIFI

L. E. Kristensen; E. F. van Dishoeck; M. Tafalla; R. Bachiller; B. Nisini; R. Liseau; U. A. Yıldız

doi:10.1051/0004-6361/201116975

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Volume 531 (July 2011)

A&A, 531 (2011) L1

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Issue		A&A Volume 531, July 2011


Article Number		L1
Number of page(s)		6
Section		Letters
DOI		https://doi.org/10.1051/0004-6361/201116975
Published online		30 May 2011

Online material

Appendix A: Gauss fit of data

The data are fitted by Gaussians, with the exception of the narrow absorption component. Figure A.1 shows the example of the H₂O 1₁₁–0₀₀ line, with the residual plotted below. Furthermore, Fig. A.1 shows the CO 3–2 line scaled and overplotted on the H₂O 1₁₁–0₀₀ line, highlighting the similar line profile in the EHV components.

	Fig. A.1 Top: Gauss fit of the H₂O 1₁₁–0₀₀ line (red) with the residual shown below (offset at − 0.1 K). The central absorption feature is not fitted. Bottom: CO 3–2 scaled to the peak intensity of H₂O in the bullets and overplotted on the H₂O 1₁₁–0₀₀ line.
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Appendix B: RADEX results

The non-LTE, escape-probability code RADEX was used to create rotational diagrams for H₂O and CO in the optically thin limit. Collisional rate coefficients are from Faure et al. (2007) and Yang et al. (2010), respectively. The same transitions as observed were then used to calculate the rotational temperature as function of T_kin and n_H. The results are shown in Fig. B.1.

RADEX was also used to calculate the optical depth, τ of the HO 1₁₀–1₀₁ line at 557 GHz. Results are shown in Fig. B.2, where also the beam-filling factor is shown as a function of H₂O column density for the three different models.

Fig. B.1

T_rot of optically thin H₂O emission (top), optically thick H₂O emission (N = 10¹⁷ cm^-2; middle) and optically thin CO emission (bottom) determined from RADEX simulations. T_rot is calculated from the same transitions as in Sect. 2, i.e., excluding the ground-state transitions. The gray area indicates the observed values of T_rot. The points indicate the different physical conditions examined; model 1 (red) has (T, n) = (150 K, 10⁶ cm^-3) for the EHV components and (100 K, 10⁶ cm^-3) for the broad component. Model 2 (blue) has (T, n) = (500 K, 10⁵ cm^-3) for the EHV components, respectively. Model 3 (green) has (T, n) = (500 K, 10⁶ cm^-3) for all components.

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	Fig. B.2 Top: τ of the HO 1₁₀–1₀₁ line. The black dashed line corresponds to the observed value in each of the three velocity components as specified in Sect. 2. Bottom: beam-filling factor for the three different components and three different models as a function of total H₂O column density. Best-fit results are marked with points in both plots.
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Table 2

H₂O, HO and CO emission in each velocity component at the source position^a.

Table 3

H₂O, HO and CO transitions observed with Herschel-HIFI^a.

© ESO, 2011

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