3 Results

3.1 Spectral imaging in H $\mathsf{_{2}}$

Lines from purely rotationally excited H₂ are clearly discernible in the CVF-image. In particular, all lines which fall in the observed spectral range, were detected and, in Table 1, their observed fluxes are listed. These refer to the 3 para-H₂ lines 0-0 S(2) 12.3, S(4) 8.0 and S(6) 6.1 $\mu$m and the 3 ortho-H₂ lines 0-0 S(3) 9.7, S(5) 6.9 and S(7) 5.5 $\mu$m. Figure 2 shows maps near SMM 1 in these six lines, delineating the spatial distribution of the rotationally excited H₂ gas along the known jet-flow from SMM 1 (Eiroa & Casali 1989; Hodapp 1999). In addition, somewhat weaker H₂ emission is also observed near SMM 3, the discussion of which will be postponed to a future paper.

 

 

Table 1: Observed H₂ fluxes near SMM 1.

Transition	Peak $^{\dagger}$	Total $^{\ddagger}$
	(10-21 W cm-2)	(10-20 W cm-2)
0-0 S(2)	$2.9 \pm 0.9$	$1.5 \pm 0.2$
0-0 S(3)	$5.2 \pm 0.6$	$4.8 \pm 0.4$
0-0 S(4)	$8.8 \pm 1.0$	$3.6 \pm 0.3$
0-0 S(5)	$19.8 \pm 1.2$	$7.0 \pm 0.5$
0-0 S(6)	$6.2 \pm 0.8$	$0.7 \pm 0.2$
0-0 S(7)	$15.6 \pm 2.8$	$5.8 \pm 0.6$
1-0 S(1)$^{\amalg}$	2.5	1.0

Notes to the table:
$^{\dagger}$ Peak emission into a 36 arcsec² pixel.
$^{\ddagger}$ Total emission over a source of 350 arcsec².
$^{\amalg}$ Estimated from Fig. 3 of Eiroa & Casali (1989).

Figure 2: CVF images toward SMM 1 in 3 ortho-H2 (upper frames) and 3 para-H2 (lower row) lines. Offsets are in arcsec and relative to the centre position (0, 0) of the LWS map. The white arcs outline the FWHM contour of the LWS beam (70 $^{\prime \prime }$) and the white spot designates the position of SMM 1. The actual CVF pixels are square 6 $^{\prime \prime }$.

3.2 LWS-maps of [O I] 63 $\mu$m, [C II] 157 $\mu$m, ortho-H $\mathsf{_{2}}$O 179.5 $\mu$m and CO 186 $\mu$m

Within the $8^{\prime}\times 8^{\prime}$ map observed with the LWS, the spatial distribution of the fine structure lines [O  I] 63 $\mu$m and [C  II] 157 $\mu$m is shown in Fig. 3 together with that of the rotational lines of H₂O ( 2₁₂-1₀₁) (connecting to the ground state) and CO (J=14-13) (lowest J-transition admitted and close in wavelength to the H₂O line).

Figure 3: Maps of integrated line fluxes of [O  I] 63 $\mu$m, [C  II] 157 $\mu$m, H2O (212-101) and CO (14-13), with individual flux levels indicated by the bars next to each frame. The crosses refer to the positions toward which the LWS spectra have been obtained.

Like the emission in [C  II] 157 $\mu$m, [O  I] 63 $\mu$m emission is observed in each position of our map, but with maximum intensity at the position of SMM 1. Secondary maxima are also seen along a ridge toward SMM 4/3/8 in the southeast-to-east. In addition, the emission is extended toward SMM 9/S 68 NW. The overall [O  I] 63 $\mu$m distribution is strikingly similar to that seen in the mm-regime in a variety of high density tracing molecules (McMullin et al. 2000). Very interesting is also the fact that, just in the northwest corner of the map, the shocked flow HH 460 (Davis et al. 1999; Ziener & Eislöffel 1999) seems to be discernible.

In [C  II] 157 $\mu$m, maximum emission is seen toward S 68 (Sharpless 1959) and the cluster in the southeast, whereas SMM 1 is inconspicuous in this map. To some extent, the [C  II] 157 $\mu$m-map is an inverted image of that seen in [O  I] 63 $\mu$m.

The molecular emision in the 179.5 $\mu$m line of ortho-H₂O and in the 186 $\mu$m line of CO is strongest toward SMM 1, but displays also some extensions along the [O  I] 63 $\mu$m ridge, i.e. toward the northwest and the southeast. The spatial resolution is not sufficient, however, to decide whether this emission is extended or due to the numerous SMM-sources in the region (cf. Fig. 3).

3.3 The line spectrum of SMM 1 from 43 to 197 $\mu$m

The continuum subtracted line spectrum of SMM 1 from 43 to 197 $\mu$m is displayed in Fig. 4, revealing a plethora of emission lines from both atomic and molecular species. In the figure, also the wavelength coverage of the ten individual LWS detectors is indicated (cf. Sect. 2.2). The identification of the lines and their parameters, as obtained from profile fitting, are listed in Tables 2 to 5. Listed are the identified species, the upper and lower states and the rest wavelength of the transition. This is followed by the observed wavelength with the measurement error and the difference between the observed and the rest wavelength. Then the line width and the line flux with fitting-errors, respectively, are tabulated and the error estimate for the line flux, i.e. $\Delta F = \sqrt{\sigma_{\rm l}^2 + \sigma_{\rm c}^2}$ where $\sigma_{\rm l}$ is the fitting error and $\sigma_{\rm c}$ is the rms-level of the surrounding continuum integrated over one spectral resolution element. In the last two columns, the type of the Gauss fitting (single or multiple component) and the LWS detector are given.

Figure 4: The LWS spectrum (43 to 197 $\mu$m) of Serpens SMM 1 with line positions indicated. For clarity the strong continuum (Larsson et al. 2000) has been subtracted. The originally four times oversampled data have been rebinned to 0.1 $\mu$m for the short wavelength (SW) and to 0.2 $\mu$m for the long wavelength (LW) spectral range. Also shown, below the spectrum, is the extent of the individual LWS detectors.

Out of a total of 8 measured CO lines, clear detections are found for 7 transitions. In addition, we identfy 5 (possibly 8) lines of ortho-H₂O, and 1 (possibly 2) of para-H₂O. Further, 4 lines of OH are clearly present in the spectrum, whereas for two more lines this status is less clear. Aside from the line emission from molecules, lines from O⁰ and C⁺ are also present. Possible implications from these results will be discussed in the following sections.

 

 

Table 2: Line fluxes of atoms and ions toward SMM 1.

Ion id	Transition	Wavelength				Flux $\times$ 1019		Single/	LWS
		($\mu$m)				(W cm-2)		Multi	Detector
		$\lambda$	$\lambda_{\rm obs}$	$\Delta \lambda$	$\sigma_{\lambda}$	F	$\Delta F$	fit
[CII]	2P3/2-2P1/2	157.74	157.72 $\pm$ 0.02	-0.02	0.46 $\pm$ 0.03	2.07 $\pm$ 0.21	0.35	S	LW 4
			157.72 $\pm$ 0.04	-0.02	0.60 Fix	2.31 $\pm$ 0.20	0.34	S	LW 4
[OI]	3P0-3P1	145.53	145.53 Fix	+0.00	0.60 Fix	0.37 $\pm$ 0.84	0.90	M	LW 4
			145.53 Fix	+0.00	0.60 Fix	0.76 $\pm$ 0.83	0.89	M	LW 3
	3P1-3P2	63.18	63.19 $\pm$ 0.01	+0.01	0.27 $\pm$ 0.01	9.5 $\pm$ 0.7	0.74	S	SW 3
			63.19 $\pm$ 0.01	+0.01	0.29 Fix	9.8 $\pm$ 0.4	0.46	S	SW 3
			63.17 $\pm$ 0.01	-0.01	0.28 $\pm$ 0.01	10.3 $\pm$ 0.9	0.96	S	SW 2
			63.17 $\pm$ 0.01	-0.01	0.29 Fix	10.5 $\pm$ 0.5	0.60	S	SW 2
[NII]	3P2-3P1	121.90					0.29	S	LW 2
[OIII]	3P1-3P0	88.36					0.47	S	LW 1
							0.32	S	SW 5
	3P2-3P1	51.82					0.73	S	SW 2

  

Table 3: CO line measurements in the spectrum of SMM 1.

$$\begin{tabular}{lccccccll} \hline\hline\\ [-3mm] Transition... ... & 118.58 & & & & & 0.29 & S & LW 2 \\ \hline \end{tabular}$$

Notes to the table:
$\Delta F = \sqrt{\sigma_{\rm l}^2 + \sigma_{\rm c}^2}$ where $\sigma_{\rm l}$ is the fitting error and $\sigma_{\rm c}$ is the rms-level of the surrounding continuum integrated over one spectral resolution element, i.e. 0.29 $\mu$m and 0.60 $\mu$m for the SW and LW detectors, respectively. S = Single line component fit; M = multi component line fit. Underlined flux values were used in the rotation diagram analysis and are shown in Fig. 7.

 

 

Table 4: H₂O line measurements in the spectrum of SMM 1.

Transition	Wavelength			Width	Flux $\times$ 1019	Err $\times$ 1019	Single/	LWS
	($\mu$m)			($\mu$m)	(W cm-2)	(W cm-2)	Multi	Detector
	$\lambda$	$\lambda_{\rm obs}$	$\Delta \lambda$	$\sigma_{\lambda}$	F	$\Delta F$	fit
ortho-H2O
221-212	180.49	180.49 $\pm$ 0.03	+0.00	0.45 $\pm$ 0.03	0.53 $\pm$ 0.11	0.24	S	LW 5
		180.49 $\pm$ 0.05	+0.00	0.60 Fix	0.60 $\pm$ 0.01	0.23	S	LW 5
212-101	179.53	179.55 $\pm$ 0.04	+0.02	0.57 $\pm$ 0.04	1.40 $\pm$ 0.24	0.32	S	LW 5
		179.55 $\pm$ 0.04	+0.02	0.60 Fix	1.43 $\pm$ 0.13	0.25	S	LW 5
303-212	174.63	174.63 $\pm$ 0.03	+0.00	0.70 $\pm$ 0.03	2.15 $\pm$ 0.24	0.33	S	LW 5
		174.63 $\pm$ 0.03	+0.00	0.60 Fix	1.97 $\pm$ 0.14	0.26	S	LW 5
		174.63 $\pm$ 0.06	+0.00	0.60 Fix	1.93 $\pm$ 0.66	0.71	M	LW 5
330-321	136.49	136.52 $\pm$ 0.09	+0.03	0.64 $\pm$ 0.11	0.85 $\pm$ 0.34	0.48	S	LW 3
		136.51 $\pm$ 0.06	+0.02	0.60 Fix	0.81 $\pm$ 0.11	0.35	S	LW 3
		136.51 Fix	+0.02	0.60 Fix	0.77 $\pm$ 0.82	0.88	M	LW 3
414-303	113.54	113.54 $\pm$ 0.04	+0.00	0.61 $\pm$ 0.04	2.96 $\pm$ 0.39	0.52	S	LW 2
		113.54 $\pm$ 0.03	+0.00	0.60 Fix	2.93 $\pm$ 0.21	0.41	S	LW 2
221-110	108.07	108.13 $\pm$ 0.05	+0.06	0.39 $\pm$ 0.02	1.29 $\pm$ 0.40	0.50	S	LW 2
		108.18 $\pm$ 0.07	+0.11	0.60 Fix	1.58 $\pm$ 0.31	0.45	S	LW 2
		107.83 $\pm$ 0.03	-0.25	0.51 $\pm$ 0.05	1.60 $\pm$ 0.24	0.52	S	LW 1
		107.84 $\pm$ 0.05	-0.24	0.60 Fix	1.79 $\pm$ 0.22	0.51	S	LW 1
321-212	75.38	75.40 $\pm$ 0.03	+0.02	0.29 $\pm$ 0.03	2.05 $\pm$ 0.51	0.60	S	SW 4
		75.40 $\pm$ 0.03	+0.02	0.29 Fix	2.03 $\pm$ 0.28	0.42	S	SW 4
441-330	49.34	49.32 $\pm$ 0.02	-0.02	0.25 $\pm$ 0.02	1.69 $\pm$ 0.29	0.37	S	SW 1
		49.32 $\pm$ 0.02	-0.02	0.29 Fix	1.81 $\pm$ 0.18	0.29	M	SW 1
para-H2O
220-111	100.98	100.66 $\pm$ 0.05	-0.32	0.57 $\pm$ 0.04	2.53 $\pm$ 0.68	0.82	S	LW 1
		100.66 $\pm$ 0.06	-0.32	0.60 Fix	2.60 $\pm$ 0.37	0.58	S	LW 1
322-211	89.99	89.99 $\pm$ 0.05	+0.00	0.44 $\pm$ 0.04	2.71 $\pm$ 0.76	0.83	S	SW 4
		90.01 $\pm$ 0.04	+0.02	0.29 Fix	2.02 $\pm$ 0.42	0.53	S	SW 4