3 Data

  
3.1 Optical data

The optical spectra were secured during two observing runs in December 1995 and December 1996. The observations were carried out with the Boller & Chivens Spectrograph on the ESO 1.52 meter telescope. The instrumental setup in these two runs is given in Table 2. In all cases, the detector was windowed down to 300 $\times$ 2048 pixels, giving a slit length of 4$\farcm$1. In the second part of the December 1996 run, the grating was changed, which split the spectra in two sets, differing in wavelength range.

Of every H II region in our sample, longslit spectra and several driftscan spectra were taken. The longslit spectra were taken at intervals of 4-5$\arcsec$ in the direction perpendicular to the slit so as to cover the whole object. The orientation of the slit was chosen such that the effects of differential refraction were minimized. The driftscan spectra scan areas ranging from 10$\arcsec$ to 60$\arcsec$, depending on scan speed and integration time, and are used to facilitate the combination of ISO and optical data. These driftscan spectra were obtained holding the slit in a fixed North-South direction. Unless stated otherwise, the reduction process described in this section is the same for both the longslit and the driftscan spectra.

The reduction of the optical spectra was done with the Image Reduction and Analysis Facility (IRAF) V2.11. The reduction involved bias subtraction, flatfielding using dome flats, and cosmic ray removal. A slit illumination function was created from sky flats to correct for illumination gradients in the dome flats along the spatial direction of the slit. These gradients, though, amounted to only a few percent going from one end of the slit to the other. Several Helium-Argon lamp exposures were made during every night for the wavelength calibration of the spectra. The Helium-Argon exposures were also used to correct for a slight misalignment of the slit with the dispersion lines of the detector.

For the flux calibration of the spectra, a response function of the total setup was derived using the combined spectra from the standard stars Feige 24, L 745-46A and G 99-37 (Oke 1974). The uncertainty in the response function, and hence in the flux calibration, was determined by overplotting the different "sub'' response functions as derived from the separate standard star exposures. The scatter in the combined "sub'' response functions as a function of wavelength was then determined. This scatter translated into an uncertainty in the flux calibration varying from 3% in the yellow, central part of the spectrum, to 5% in the red and blue parts at the ends. From the combined "sub'' response functions a master response function was derived. The 2D-spectra were then flux calibrated. A correction for atmospheric extinction was made with a standard extinction curve for the site using the airmass in mid-observation. Given the short exposure times of the spectra, the change in the airmass during the observation was negligible.

The background emission was subtracted from the 2D-spectra by fitting a constant function to every dispersion line. To this end, windows were placed along the slit where no nebular emission was present. In some of the spectra, however, the emission was seen to extend all across the slit, particularly in H$\alpha$ and [O III] 5007 Å. In these cases, two "versions'' of the same spectrum were created, one with and one without the background emission removed. This procedure was necessary because of the multitude of nightsky lines in the far red which would otherwise make the identification of the nebular lines difficult.

From the spectra thus reduced a 1D-spectrum was extracted. For the stationary longslit spectra, the number of 1D-spectra extracted and their placing across the slit depend highly on the source under consideration. We therefore defer their discussion to future papers on the separate objects. As far as the driftscan spectra are concerned, the appropriate width and placing of the extraction window for every separate object was derived from the projection of the ISO-SWS band 4 aperture (20 $\arcsec \times 33\arcsec$) on the slit. Only for the object N159-5 the extraction window was made smaller to tightly fit the knot seen in the center panel of Fig. 2, this to increase the S/N ratio of the spectrum. Decreasing the width of the extraction window to match the projection of the other three (smaller) apertures did not change the derived 1D-spectra significantly.

Fluxes were derived from the 1D-spectra with the SPLOT package. The flux of each line in the spectra was measured several times by fitting Gaussian profiles to the lines as well as by simple pixel integration. These measurements were repeated at least eight times for every line in order to get an estimate of the uncertainties in the line flux due to noise and continuum fitting. For most of the lines the profile was adequately decribed by a Gaussian, but for some of the stronger lines sometimes a small blue wing was seen. In such cases, the flux derived from the pixel integration was adopted, but the difference between the fluxes derived in the two different ways amounted to only a few percent.

In the case of a spectrum from which it was impossible to subtract the background emission, the line fitting procedure was a bit different. For those lines which did not extend all across the slit, the background subtracted version of the 1D-spectrum was used to derive the fluxes. These lines included the ones blue-wards from H$\beta$ and red-wards from H$\alpha$. The lines extending all across the slit were measured in both versions of the 1D-spectrum. The difference in the fluxes derived for those lines was treated as an extra uncertainty.

   

Table 3: The optical fluxes for the LMC objects N160A1, N160A2, N159-5, N157B and the four pointings in 30 Doradus. The first and second column give the wavelength and identification of the lines, respectively. The fluxes are given relative to H$\beta$ ( $\times 100$). Given in the last row is the reddening $E_{\beta - \alpha }$ in magnitudes. The flux uncertainties are coded as follows: A < 5%, 5% $\le$ B < 7.5%, 7.5% $\le$ C < 10%, 10% $\le$ D < 12.5%, 12.5% $\le$ E < 15%, F $\ge$ 15%.

$\lambda$ (Å)	Identifier	N160A1		N160A2		N159-5		N157B		30 Dor#1		30 Dor#2		30 Dor#3		30 Dor#4
		$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err
3727	[O II]	165.5	C	164.6	C	246.0	C	223.0	B	-	-	-	-	-	-	-	-
3869	[Ne III]	29.4	B	26.5	C	29.5	E	19.9	D	-	-	-	-	-	-	-	-
3888	H$\zeta$	17.4	C	16.5	C	17.3	E	15.8	D	-	-	-	-	-	-	-	-
3968	[Ne III]	23.6	B	22.2	C	25.2	F	21.3	E	-	-	-	-	-	-	-	-
4101	H$\delta$	24.7	B	24.2	B	24.6	F	23.3	C	24.1	B	23.0	A	24.9	A	27.3	B
4340	H$\gamma$	44.4	B	44.1	B	47.0	D	42.4	C	50.5	A	48.9	A	49.3	A	52.6	B
4363	[O III]	2.4	D	1.8	E	-	-	4.8	F	4.8	B	3.8	C	3.8	B	3.7	E
4471	He I	3.8	C	3.6	D	-	-	3.5	F	4.2	C	3.7	D	4.3	B	5.4	E
4711	[Ar IV]	-	-	-	-	-	-	-	-	-	-	-	-	0.88	E	-	-
4861	H$\beta$	100.0	A	100.0	A	100.0	B	100.0	B	100.0	A	100.0	A	100.0	A	100.0	A
4959	[O III]	139.9	A	126.5	A	120.0	B	108.0	B	189.0	A	167.0	C	168.0	A	151.0	A
5007	[O III]	423.6	A	382.1	A	368.0	B	324.0	B	566.0	A	502.0	C	497.0	A	457.0	A
5200	[N I]	-	-	0.49	F	-	-	-	-	-	-	-	-	-	-	-	-
5270	[Fe III]	-	-	-	-	-	-	-	-	0.28	F	-	-	0.26	F	-	-
5517	[Cl III]	0.45	E	0.41	F	-	-	-	-	-	-	0.55	F	0.56	D	-	-
5537	[Cl III]	0.31	F	0.25	F	-	-	-	-	-	-	0.44	F	0.37	D	-	-
5754	[N II]	0.34	F	-	-	-	-	-	-	-	-	-	-	-	-	-	-
5875	He I	12.1	A	11.7	A	12.8	C	11.7	B	11.7	B	13.1	A	12.7	A	12.1	A
6302	[O I]	1.60	B	1.27	C	2.7	F	5.5	C	0.50	E	-	-	0.59	C	1.2	C
6312	[S III]	1.43	B	1.44	C	1.3	F	1.6	C	1.7	C	1.7	F	1.7	B	1.7	C
6362	[O I]	0.71	F	-	-	1.0	F	2.2	F	-	-	-	-	0.29	F	0.68	F
6563	H$\alpha$	286.0	A	286.0	A	286.0	B	286.0	B	286.0	A	286.0	A	286.0	A	286.0	A
6585	[N II]	18.7	B	18.3	B	21.0	B	22.2	C	5.2	B	4.7	B	7.9	A	12.9	A
6678	He I	3.3	B	3.2	B	3.4	C	3.8	D	3.3	B	3.3	B	3.6	A	3.2	B
6717	[S II]	12.7	C	11.7	C	18.1	B	29.1	B	3.7	B	5.1	B	4.3	A	8.6	A
6730	[S II]	10.1	C	9.3	C	14.3	B	24.5	B	3.2	B	4.1	B	4.1	A	7.3	A
7065	He I	3.2	B	3.3	B	4.5	C	2.4	E	3.5	B	3.2	B	3.7	A	2.5	B
7137	[Ar III]	11.9	A	11.2	A	12.4	B	10.5	B	11.5	A	11.3	A	12.8	A	11.4	A
7281	He I	0.61	E$^\dag$	0.59	E$^\dag$	-	-	-	-	0.46	E$^\dag$	0.59	E$^\dag$	0.60	C$^\dag$	0.53	E$^\dag$
7320	[O II]	2.6	B$^\dag$	2.5	B$^\dag$	3.5	C$^\dag$	-	-	1.3	C$^\dag$	1.2	B$^\dag$	1.7	B$^\dag$	1.9	B$^\dag$
7330	[O II]	2.0	B$^\dag$	2.0	B$^\dag$	2.7	C$^\dag$	-	-	1.2	C$^\dag$	1.0	B$^\dag$	1.4	B$^\dag$	1.6	B$^\dag$
7450	[Fe II] (?)	3.0	C$^\dag$	2.8	C$^\dag$	2.4	F$^\dag$	5.0	F$^\dag$	-	-	-	-	0.27	F$^\dag$	-	-
7726	He I	0.57	D	0.45	E	-	-	-	-	0.35	F	-	-	0.37	E	-	-
7751	[Ar III]	3.1	B	2.8	B	3.0	D	-	-	2.9	B	2.9	C	3.3	B	2.7	B
8750	P 12	1.34	D$^\ddag$	1.3	D$^\ddag$	2.0	F$^\ddag$	-	-	1.2	E$^\ddag$	1.1	D$^\ddag$	1.3	C$^\ddag$	1.4	D$^\ddag$
8862	P 11	2.10	D$^\ddag$	2.0	C$^\ddag$	2.4	F$^\ddag$	-	-	1.6	D$^\ddag$	1.5	D$^\ddag$	1.8	C$^\ddag$	1.6	E$^\ddag$
9015	P 10	2.05	D$^\ddag$	2.1	D$^\ddag$	3.3	F$^\ddag$	-	-	1.7	F$^\ddag$	1.8	C$^\ddag$	1.9	B$^\ddag$	1.7	D$^\ddag$
9069	[S III]	37.9	A$^\ddag$	35.3	A$^\ddag$	42.6	B$^\ddag$	35.6	B$^\ddag$	28.8	A$^\ddag$	27.0	A$^\ddag$	32.7	A$^\ddag$	29.9	A$^\ddag$
9229	P 9	3.53	B$^\ddag$	3.4	C$^\ddag$	4.1	F$^\ddag$	-	-	3.4	C$^\ddag$	3.1	C$^\ddag$	3.8	B$^\ddag$	3.1	C$^\ddag$
9532	[S III]	87.1	A$^\ddag$	82.2	A$^\ddag$	91.6	B$^\ddag$	85.8	B$^\ddag$	79.4	A$^\ddag$	-	-	97.5	A$^\ddag$	85.3	A$^\ddag$
	$E_{\beta - \alpha }$	0.27		0.30		0.59		0.25		0.40		0.35		0.33		0.59

$^\dag$ These lines sit in an absorption feature near 7200 Å.
$^\ddag$ The fluxes are affected by telluric absorption. The extra uncertainty arising from this is not included here.

   

Table 4: The same as in Table 3 but then for the LMC objects N11A, N83B, N79A and N4A, and for the SMC objects N88A, N66 and N81.

$\lambda$ (Å)	Identifier	N11A		N83B		N79A		N4A		N88A		N66			N81
		$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err	$I_\lambda$/$I_\beta$	Err		$I_\lambda$/$I_\beta$	Err
3727	[O II]	-	-	-	-	233.0	B	152.2	B	95.6	B	116.9	C		137.0	B
3869	[Ne III]	-	-	-	-	17.7	C	28.0	B	53.6	B	34.1	C		46.0	C
3888	H$\zeta$	-	-	-	-	14.7	C	18.4	C	11.4	C	15.3	E		15.0	D
3968	[Ne III]	-	-	-	-	18.9	C	23.9	B	29.1	C	26.1	F		27.6	B
4101	H$\delta$	25.9	C	24.5	B	23.4	C	24.7	B	24.7	C	19.7	D		25.4	B
4340	H$\gamma$	52.9	B	54.5	A	41.5	B	44.7	B	44.4	B	40.9	C		45.6	B
4363	[O III]	2.9	F	2.5	F	2.4	F	2.6	F	12.0	C	5.6	F		7.4	B
4471	He I	4.6	C	4.0	E	3.6	E	3.9	D	3.6	E	3.1	F		3.8	D
4711	[Ar IV]	-	-	-	-	-	-	-	-	-	-	-	-		-	-
4861	H$\beta$	100.0	A	100.0	A	100.0	B	100.0	A	100.0	A	100.0	B		100.0	A
4959	[O III]	128.0	A	92.1	A	101.0	A	142.0	A	222.0	A	156.0	B		175.0	A
5007	[O III]	387.0	A	277.0	A	306.0	A	430.0	A	672.0	A	469.0	B		528.0	A
5200	[N I]	-	-	-	-	-	-	-	-	-	-	-	-		0.4	F
5270	[Fe III]	-	-	-	-	-	-	-	-	-	-	-	-		-	-
5517	[Cl III]	-	-	-	-	-	-	-	-	-	-	-	-		-	-
5537	[Cl III]	-	-	-	-	-	-	-	-	-	-	-	-		-	-
5754	[N II]	-	-	-	-	-	-	0.41	F	-	-	-	-		-	-
5875	He I	12.3	B	11.4	A	11.4	A	12.4	A	12.9	B	11.0	C		10.9	B
6302	[O I]	1.7	D	1.3	D	1.8	C	1.2	C	1.6	C	2.3	E		1.1	C
6312	[S III]	1.5	D	1.4	C	1.3	C	1.5	C	1.6	C	1.8	E		1.6	C
6362	[O I]	-	-	-	-	0.76	F	-	-	-	-	1.4	F		-	-
6563	H$\alpha$	286.0	A	286.0	A	286.0	A	286.0	A	286.0	A	286.0	B		-	-
6585	[N II]	17.0	C	22.7	A	23.8	A	13.3	A	5.3	B	6.1	C		5.5	B
6678	He I	3.3	C	3.2	B	3.1	C	3.3	B	2.9	B	3.1	D		2.5	B
6717	[S II]	11.3	E	14.4	C	15.1	A	9.1	A	5.2	B	10.1	B		6.9	B
6730	[S II]	9.3	E	11.8	B	12.5	A	6.9	A	4.5	B	7.0	C		5.2	B
7065	He I	3.2	E	3.8	B	3.9	C	2.6	B	9.3	A	2.9	F		2.7	B
7137	[Ar III]	11.5	B	10.2	A	10.6	B	11.4	A	10.7	A	8.3	C		8.3	A
7281	He I	-	-	-	-	0.74	F$^\dag$	0.68	F$^\dag$	0.87	E$^\dag$	-	-		0.6	F$^\dag$
7320	[O II]	4.8	C$^\dag$	4.0	B$^\dag$	4.1	B$^\dag$	2.2	C$^\dag$	2.9	B$^\dag$	2.1	E$^\dag$		2.5	C$^\dag$
7330	[O II]	3.8	C$^\dag$	3.5	B$^\dag$	3.3	B$^\dag$	1.8	C$^\dag$	2.2	B$^\dag$	2.0	F$^\dag$		1.9	C$^\dag$
7450	[Fe II] (?)	-	-	-	-	5.9	C$^\dag$	3.4	C$^\dag$	1.7	F$^\dag$	3.6	F$^\dag$		-	-
7726	He I	-	-	-	-	-	-	0.66	E	0.6	F	-	-		1.2	D
7751	[Ar III]	3.3	D	2.7	C	2.7	C	2.9	B	2.2	D	-	-		2.0	C
8750	P 12	-	-	1.5	F$^\ddag$	1.8	D$^\ddag$	1.1	E$^\ddag$	1.8	E$^\ddag$	-	-		1.2	F$^\ddag$
8862	P 11	-	-	1.7	F$^\ddag$	2.7	F$^\ddag$	1.9	E$^\ddag$	1.7	E$^\ddag$	-	-		1.5	F$^\ddag$
9015	P 10	-	-	1.6	F$^\ddag$	2.4	F$^\ddag$	2.9	E$^\ddag$	2.8	F$^\ddag$	-	-		2.1	F$^\ddag$
9069	[S III]	27.5	A$^\ddag$	28.5	A$^\ddag$	38.3	A$^\ddag$	34.7	A$^\ddag$	17.5	B$^\ddag$	20.7	D$^\ddag$		18.0	B$^\ddag$
9229	P 9	-	-	3.8	F$^\ddag$	4.0	D$^\ddag$	-	-	4.0	D$^\ddag$	-	-		3.0	C$^\ddag$
9532	[S III]	77.8	A$^\ddag$	81.5	A$^\ddag$	90.4	A$^\ddag$	75.8	A$^\ddag$	20.7	B$^\ddag$	45.7	D$^\ddag$		37.7	B$^\ddag$
	$E_{\beta - \alpha }$	0.25		0.27		0.13		0.27		0.01		0.26		$E_{\beta - \delta}$	-0.08$^\star$

$^\dag$ These lines sit in an absorption feature near 7200 Å.
$^\ddag$ The fluxes are affected by telluric absorption. The extra uncertainty arising from this is not included here.
$^\star$ The H$_\alpha$ line was saturated. The Balmer-decrements H$_\gamma$/H$_\beta$ and H$_\delta$/H$_\beta$were used for the extinction correction. Given here is $E_{\beta - \delta}$.

   

Table 5: The ISO-SWS/LWS fluxes for the LMC objects N160A1, N160A2, N159-5, N157B, N4A, N11A, N83B and N79A. The first and second column give the wavelength and identification of the lines, respectively. The fluxes are given in 10^-16 W m^-2. The flux uncertainties are coded as follows: A < 5%, 5% $\le$ B < 10%, 10% $\le$ C < 15%, 15% $\le$ D < 20%, 20% $\le$ E < 30%, F $\ge$ 30%.

$\lambda$ ($\mu$m)	Identifier	N160A1		N160A2		N159-5		N157B		N4A		N11A		N83B		N79A
		Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err
4.05	Br$\alpha$	51.7	C	55.2	C	12.6	C	-	-	10.7	E	-	-	12.3	D	-	-
2.63	Br$\beta$	24.0	B	28.4	B	5.98	C	3.65	C	10.8	B	-	-	6.53	B	-	-
7.46	Pf$\alpha$	16.1	F	15.5	D	-	-	-	-	6.50	D	-	-	-	-	-	-
4.65	Pf$\beta$	7.73	D	9.43	D	-	-	-	-	-	-	-	-	-	-	-	-
12.8	[Ne II]	112	E	124	E	51.0	E	28.5	E	41.1	E	18.9	E	18.9	E	-	-
15.6	[Ne III]	438	C	332	C	152	C	49.5	C	121	C	42.6	C	26.7	C	5.39	C
36.0	[Ne III]	70.6	F	55.9	F	17.9	F	7.35	F	20.4	F	6.22	F	4.92	F	-	-
18.7	[S III]	317	C	268	C	74.2	C	46.5	C	93.6	C	36.1	C	28.8	C	1.64/6.32	F/C
33.5	[S III]	643	F	491	F	204	F	116	F	212	F	60.3	F	52.2	F	24.8	F
10.5	[S IV]	289	C	194	C	56.7	C	11.7	C	75.9	C	23.3	C	18.1	C	2.49	C
34.8	[Si II]	111	F	120	F	80.5	F	44.0	F	32.5	F	14.4	F	15.1	F	14.2	F
6.98	[Ar II]	6.47	E	11.3	F	-	-	-	-	-	-	-	-	-	-	-	-
8.99	[Ar III]	70.3	C	76.2	C	19.9	C	8.72	D	25.8	C	11.6	C	10.7	C	-	-
25.99	[Fe II]	-	-	-	-	-	-	4.52	E	-	-	-	-	-	-	-	-
63.1	[O I]	890	B	890	B	540	B	106	B	182	B	270	B	153	C	63	C
145.5	[O I]	53	B	53	B	39	B	9	E	13	C	8.3	D	8.3	D	3.5	D
51.8	[O III]	3000	B	3000	B	1900	B	815	B	800	B	1140	B	130	C	151	C
88.3	[O III]	2700	B	2700	B	2250	B	1450	B	850	C	1710	B	140	C	275	C
25.91	[O IV]	-	-	-	-	-	-	5.09	D	-	-	-	-	-	-	-	-
121.8	[N II]	<22	$\star$	<22	$\star$	<23	$\star$	<7	$\star$	<7.5	$\star$	<14	$\star$	<6	$\star$	<5	$\star$
57.3	[N III]	275	B	275	B	187	B	77	C	67	C	133	C	<35	$\star$	20	F
157.7	[C II]	595	B	595	B	560	B	170	B	160	B	270	B	156	B	81	B

$^\star$ 3 $\sigma$ upper limit only.

 

 

Table 6: The same as in Table 5 but then for the four pointings in 30 Doradus and the SMC sources N88A, N66 and N81.

$\lambda$ ($\mu$m)	Identifier	30 Dor#1		30 Dor#2		30 Dor#3		30 Dor#4		N88A		N66		N81
		Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err	Flux	Err
4.05	Br$\alpha$	34.9	C	53.5	C	95.9	C	26.6	C	-	-	-	-	-	-
2.63	Br$\beta$	16.0	B	27.0	B	45.8	B	12.7	C	8.45	C	1.83	F	5.60	D
7.46	Pf$\alpha$	-	-	19.6	C	38.3	C	12.7	D	-	-	-	-	-	-
4.65	Pf$\beta$	-	-	-	-	20.2	D	-	-	-	-	-	-	-	-
3.74	Pf$\gamma$	-	-	-	-	14.1	B	-	-	-	-	-	-	-	-
3.29	Pf$\delta$	-	-	-	-	9.68	B	-	-	-	-	-	-	-	-
3.04	Pf$\epsilon$	-	-	-	-	8.73	C	-	-	-	-	-	-	-	-
2.87	Pf$\zeta$	-	-	-	-	4.92	C	-	-	-	-	-	-	-	-
12.8	[Ne II]	70.4	E	100	E	169	E	72.0	E	-	-	4.77	E	2.90	E
15.6	[Ne III]	371	C	689	C	1120	C	404	C	25.1	C	15.0	C	21.4	C
36.0	[Ne III]	109	F	123	F	194	F	87.1	F	6.75	F	-	-	1.60	F
18.7	[S III]	278	C	381	C	554	C	270	C	8.99	C	7.18	C	14.1	C
33.5	[S III]	785	F	921	F	1650	F	754	F	8.86	F	20.1	F	23.2	F
10.5	[S IV]	246	C	448	C	761	C	186	C	55.1	C	9.71	C	15.9	C
34.8	[Si II]	152	F	107	F	1440	F	116	F	13.1	F	-	-	6.20	F
6.98	[Ar II]	-	-	-	-	-	-	-	-	-	-	-	-	-	-
8.99	[Ar III]	49.3	C	71.9	C	146	C	45.7	C	8.07	D	3.55	E	3.90	C
21.8	[Ar III]	-	-	-	-	19.8	D	-	-	-	-	-	-	-	-
25.99	[Fe II]	-	-	-	-	-	-	-	-	-	-	-	-	-	-
63.1	[O I]	910	B	970	B	1140	B	830	B	86	B	105	D	37	B
145.5	[O I]	54	C	56	E	78	C	70	C	3	F	5	C	<2	-
51.8	[O III]	10000	B	12000	B	12200	B	8800	B	85	D	340	D	67	E
88.3	[O III]	10200	B	11700	B	11700	B	9400	B	22	F	590	C	74	E
25.91	[O IV]	-	-	-	-	-	-	-	-	-		-	-	-	-
121.8	[N II]	<26	$\star$	<19	$\star$	<25	$\star$	<24	$\star$	<4.5	$\star$	<7	$\star$	<2.5	$\star$
57.3	[N III]	770	B	910	B	970	B	810	B	<32	$\star$	<67	$\star$	<38	$\star$
157.7	[C II]	575	B	500	B	600	B	610	B	35	B	58	C	14	E

$^\star$ 3 $\sigma$ Upper limit only.

The line fluxes were corrected for extinction using the Balmer-decrement H$\alpha$/H$\beta$. The only exception here was for some of the spectra of SMC-N81 for which the H$\alpha$ line was sometimes saturated and H$\delta$/H$\beta$ had to be used instead. For the unreddened decrements, the Baker & Menzel (1938) Case B values from Storey & Hummer (1995) were taken for $T_{\rm e}$ = 10 000 Kelvin and $n_{\rm e}$ = 100 cm^-3. The correction was applied taking the extinction curve towards the Magellanic Clouds as parameterized by Howarth (1983), with the usual relation

$$% \log(I_\lambda/I_\beta) = \log(F_\lambda/F_\beta) + C({\rm H}_\beta)f_\lambda,$$ (1)

with $I_\lambda/I_\beta$ and $F_\lambda/F_\beta$ the dereddened and reddened fluxes relative to H$\beta$ respectively, $f_\lambda$ the extinction curve, and $C({\rm H}_\beta$) the reddening parameter derived from the decrement H$\alpha$/H$\beta$. The amount of extinction in the driftscan spectra is generally low. Assuming an $R_{\rm V}$ of 3.1, the values for $A_{\rm V}$ range from $\sim$ 0.1 mag for SMC-N66 to as high as 1.7 mag for the LMC object N159-5.

The line fluxes of a representative sub-sample of the driftscan spectra of the program objects are given in Tables 3 and 4. For all the objects, the spectrum covering the wavelength range from 3400 Å to 10 000 Å is given. For LMC-N83B, LMC-N11A and the pointings in 30 Doradus, however, only driftscan spectra covering the wavelength range from 4000 Å to 9800 Å were available. The error in the fluxes as given in the tables is due to uncertainties in the flux calibration, noise and uncertainties arising from the continuum fitting and background subtraction. The error due to uncertainties in the applied reddening correction is not included, but a typical error for $E_{\beta - \alpha }$ resulting from the uncertainty in the H$\alpha$/H$\beta$ decrement is in the order of 0.03 mag. An extra source of uncertainty exists in the fluxes redward from 8000 Å  which is a spectral region that can be heavily affected by absorption from atmospheric water. This absorption was clearly present in the standard star exposures and in the objects with a strong continuum. The absorption was not "divided'' out of the spectra, but an attempt was made to derive the extra uncertainty in the flux arising from this problem (see Sect. 4.2).

  
3.2 Infrared data

  
3.2.1 Short Wavelength Spectrometer

The infrared data obtained with the Short Wavelength Spectrometer (SWS, de Graauw et al. 1996) on board ISO consist of separate line scans (AOT2, covering wavelength ranges from 0.02 to 0.6 $\mu$m), AOT6 scans (30 Doradus#1, covering wavelength ranges from 0.22 to 1.7 $\mu$m for wavelenghts shorter than 7.0 $\mu$m, and from 5.1 to 15 $\mu$m for longer wavelengths), and one archival full-grating scan (AOT1 speed 4, 30 Doradus #3). The observations were carried out during the revolutions 136-298 and 519-750. The total spectral coverage of the SWS instrument ranges from 2.4 $\mu$m to 45.2 $\mu$m. This range is roughly divided into 4 sub-ranges or bands associated with 4 separate detector blocks of 12 detectors each. Each band has its own aperture that increases in size with increasing wavelength. The positions of the band 4 ISO-SWS aperture (20 $\arcsec\times$ 33$\arcsec$) on the sky are shown in Figs. 2 and 3. The SWS AOT2 data were reduced using version 6.0 of the Standard Product Generation pipeline as implemented in Interactive Analysis (IA³). The AOT6 and AOT1 data were processed with version 8.7. A recalibration of the AOT2 data with pipeline version 8.7 did not change the reduction results from version 6.0, so the first ones were retained. In all cases, the reduction process started at the Standard Processed Data (SPD) level.

The reduction of every SPD involved the steps of a zeroth order correction for memory effects, dark current subtraction, response calibration, flux calibration, and a correction for the velocity of the ISO spacecraft in the line of sight towards the object. Special attention was paid to the dark current subtraction step where, when possible, a correction was made for variations in the dark current during a scan. The absence of a continuum in most of the scans made this not too difficult. After the dark current subtraction, the separate up and down scans were checked for symmetry. Finally, bad detectors were removed from the SPD and an Auto Analysis Result (AAR) was extracted. The AAR was then flatfielded, sigma clipped to remove spurious points from the scans and rebinned to the default resolution for the particular observing template (3000 for AOT2/AOT6 and 2000 for AOT1 speed 4). This was done for the up and down scans separately, as well as for the combined data.

Fluxes were derived from the AAR by fitting Gaussians to the line profiles using the line-fitting routines within the ISO Spectral Analysis Package (ISAP). The fluxes were independently checked with self-developed line-fitting software. In all cases, both flux measurements agreed well. The fluxes derived with the ISAP routines from the combined up and down scans are given in Tables 5 and 6. The fluxes have not been corrected for possible extinction. The highest Br$\alpha$/Br$\beta$ ratio found in our SWS spectra is 2.18 $\pm$ 0.32, which is comparable with the Storey & Hummer (1995) Case B value of 1.76 for $T_{\rm e}$ = 10 000 Kelvin and $n_{\rm e}$ = 100 cm^-3. For some of our objects no estimate of the possible extinction could be made because of the absence of suitable hydrogen recombination lines. The uncertainties in the line fluxes arise mainly from noise, uncertainties in the flux calibration and from the differences in the fluxes as measured from the separate up and down AARs. For most of the objects, the main contributor to the error in the flux is the uncertainty in the flux calibration, which can be as high as 30% for the band 4 lines.

  
3.2.2 Long Wavelength Spectrometer

The Long Wavelength Spectrometer (LWS, Clegg et al. 1996) on board ISO was used in AOT1 mode to get full grating scan spectra covering the wavelength range from 43 $\mu$m to 196 $\mu$m. Over this spectral range, the resolving power varies from 140 to 330. The total spectral range covered is split into two sets of five parts each, a Short Wavelength part (SW, 43-93 $\mu$m) and a Long Wavelength part (LW, 84-196 $\mu$m). Both the SW and LW part have their own set of 5 detectors (SW 1-5 and LW 1-5). The total spectrum is formed by adding the subspectra from each of the ten separate detectors in the LWS. For each source and for each of the ten detectors, six scans were obtained. The positions of the LWS beam on the sky are shown in Figs. 2 and 3.

The spectra were reduced with LWS Interactive Analysis (LIA) V8.7, starting at the SPD level. The reduction process involved six separate steps. In the first reduction step, the absolute response of the detectors is calibrated using the illuminator flashes bracketing every observation. Following this is a correction for the drift in responsivity of every detector. The conversion from photocurrents (V s^-1) to flux units (W cm^-2 $\mu$m^-1) is done in two steps: the relative response correction and the spectral element correction. The first of these two steps corrects for the wavelength-dependent responsivity of every separate detector, while the second step corrects for the size of its spectral element. Next, a dark current correction was applied. The last reduction steps were the wavelength calibration of the spectra and a correction for the line-of-sight velocity of the ISO spacecraft towards the object. For those objects for which the continuum was very weak (flux density lower than 300 Jy at 100 $\mu$m) the dark current subtraction was done a second time with extra care. This was done to prevent the baselines of the separate scans from becoming negative as a result of inaccurate dark current subtraction. The thus reduced spectra were further processed in ISAP, where they were manually deglitched, sigma clipped to remove the remaining outlying points and corrected for fringes. The up and down scan spectra were reduced separately and in combined form. The ten subspectra were then combined to give the total spectrum. The different subspectra were not corrected for detector-to-detector jumps in the baseline (stitching).

Figure 4: The optical and infrared spectra from N159-5. The top part shows the optical ( left) and LWS ( right) spectra, the bottom part the SWS line scans.

Figure 5: The optical and infrared spectra from N83B. The top part shows the optical ( left) and LWS ( right) spectra, the bottom part the SWS line scans.

Figure 6: The optical and infrared spectra from 30 Doradus#1. Note the almost continous spectral coverage over three decades.

The line fluxes were measured in the same way as the SWS lines by fitting Gaussians (see Sect. 3.2.1). The approximation of the LWS lines by Gaussians introduces errors in the measured flux of less than 2.5% (Gry et al. 2000). The FWHM of the fitted Gaussians was held constant at 0.283 $\mu$m for the SW detectors and at 0.584 $\mu$m for the LW detectors. Extensive calibration of LWS has shown the FWHM of the lines to be constant for both sets of detectors (Gry et al. 2000). The fluxes were measured in the separate up and down scans and in the combined spectra. The fluxes from the combined up and down scans are given in Tables 5 and 6. For lines of which the flux was less than three times the noise level only an upper limit is given. No extinction correction has been applied to the LWS fluxes (see Sect. 3.2.1). Sources of uncertainty in the line fluxes include noise, differences between the fluxes measured in the up and down scan and the uncertainty in the absolute flux calibration. The uncertainty due to noise was determined from line-fit residuals. The main source of error is the uncertainty in the flux calibration. For strong sources, this uncertainty is in the order of 10%. For weak sources or for sources with a complex morphology, however, this uncertainty can be as high as 30%. These numbers apply to every detector except the detectors SW1 and LW2 for which the calibration is less clear.

3.3 The spectra

Examples of the spectra are given for the LMC objects N159-5 (Fig. 4) and N83B (Fig. 5). Shown in these Figures are the optical spectrum (upper left panel), the LWS spectrum (upper right panel) and the separate SWS line scans (lower panel). Also shown in Fig. 6 are the combined optical and infrared spectra of 30 Doradus#1. These spectra serve as an example of the general quality of our data, where the spectra of LMC-N83B represent the lower end of the quality scale. It is worth noting that the spectral coverage of the 30 Doradus#1 spectra is almost continuous and spans three decades.