L1448

2 Observations and data reduction

The spectra presented in this study were obtained using the ISO satellite (Kessler et al. 1996) with the SWS (de Graauw et al. 1996) and the LWS (Clegg et al. 1996) instruments. A log of the observations is provided in Table1.

For CepA, the positions of the spectrograph apertures are displayed in Fig.1. Our position CepA "East'' includes data with object names CepA IRS6A and CepA (except for observation 79201033) in the ISO data archive, while CepA "West'' assembles the CepA (W), CepA PK2 and the 79201033 data.

For L1448, the positions of the spectrograph apertures are shown in Fig.2. Here, we have six different positions, which we name N2, N1 in the northern lobe, C in the centre, and S1, S2, S3 in the southern lobe. They include the data with ISO names (see Table1) N and IRS3 for position N2, N2 for N1, L1448ON for C, S1 for S1, S for S2, and S2 and SIO for S3.

  

 

Table 1: Observation log for the CepheusA and L1448 data.

TDT	Object (ISO)	Position	$\alpha$(J2000)	$\delta$(J2000)	AOT
09605051	CepAPK2	West	22 56 05	+61 01 57	SWS02
10101553	CepAPK2	West	22 56 05	+61 01 59	LWS01
22000636	CepAIRS6A	East	22 56 19	+61 02 01	SWS02
22001001	CepA(W)	West	22 56 05	+61 01 57	SWS02
24800552	CepAPK2	West	22 56 05	+61 01 57	SWS07
28301183	CepA	East	22 56 21	+61 02 02	LWS01
41400837	CepA	East	22 56 21	+61 02 03	SWS06
46500654	CepAPK2	West	22 56 05	+61 01 59	LWS04
46500669	CepAPK2	West	22 56 05	+61 01 59	LWS01
46500801	CepA(W)	West	22 56 05	+61 01 59	LWS04
46500802	CepA(W)	West	22 56 05	+61 01 59	LWS01
56300803	CepA	East	22 56 18	+61 01 50	SWS07
56300918	CepA	East	22 56 18	+61 01 48	LWS04
56301021	CepA	East	22 56 18	+61 01 50	SWS02
56600809	CepAIRS6A	East	22 56 19	+61 02 01	SWS02
56600810	CepAIRS6A	East	22 56 20	+61 01 59	LWS02
65701021	CepA	East	22 56 18	+61 01 50	SWS02
79201033	CepA	West	22 56 05	+61 01 57	SWS02
84300404	CepAIRS6A	East	22 56 20	+61 01 59	SWS01
65300362	L1448N2	N1	03 25 37	+30 44 42	LWS01
65300363	L1448S1	S1	03 25 40	+30 43 24	LWS01
65300364	L1448S2	S3	03 25 41	+30 41 59	LWS01
65300701	L1448	C	03 25 39	+30 44 05	LWS01
65300702	L1448N	N2	03 25 36	+30 45 20	LWS01
65300703	L1448S	S2	03 25 41	+30 42 44	LWS01
81401066	L1448ON	C	03 25 39	+30 44 05	SWS02
81401067	L1448IRS3	N2	03 25 36	+30 45 20	SWS02
81601568	L1448N2	N1	03 25 37	+30 44 42	SWS02
81601569	L1448SIO	S3	03 25 41	+30 41 58	SWS02
84701470	L1448S1	S1	03 25 40	+30 43 24	SWS02
84701471	L1448S	S2	03 25 41	+30 42 44	SWS02

Figure 2: Positions of apertures of SWS and LWS observations in L1448 superimposed on an image in the 1-0S(1) line of H2 at 2.12$\mu$m.

2.1 SWS data

The ISO SWS instrument covered the wavelength range from 2.38 to 45.2$\mu$m. The two grating spectrometers had a spectral resolution of $R\approx1000{-}2000$ (AOT SWS01,02,06; see Table1), corresponding to a velocity resolution of $\Delta\nu\approx150{-}300$ kms^-1. Higher resolution ( $R\approx 30\,000$) was achieved by inserting one of the two Fabry-Pérot filters (wavelength range $15{-}26~\mu$m, and $26{-}35~\mu$m respectively; AOT SWS07). The aperture of the SWS instrument is rectangular, with a size depending on the detector (i.e., wavelength). The typical aperture sizes of $14\hbox{$^{\prime\prime}$ }\times 27\hbox{$^{\prime\prime}$ }$are shown in Figs.1 and 2. For more details on the instrument and AOTs see the ISO Handbook, Volume VI: SWS-The Short Wavelength Spectrometer and de Graauw et al. 1996.

The data were reduced using the standard pipeline version 8.4. We deglitched and flux calibrated the spectra with the ISO Spectral Analyses Package (ISAP 1.6a). Line fluxes (Gaussian fit centred on the line) were measured above the continuum (fit by a second order polynomial). We measured the line fluxes for each observation (TDT number) separately. Then the fluxes of the same line were averaged for each of our positions (see Table1). "Lines'' with a measured FWHM significantly smaller than the instrumental profile are not included, because we do not consider them as real.

2.2 LWS data

With the ISO LWS instrument, observations were carried out in the wavelength range from 43$\mu$m up to 196.9$\mu$m. Like with SWS, grating (AOT LWS01,02) or Fabry-Pérot (AOT LWS04) modes are available. Grating scans have a resolving power between 150-300 and the spectral resolution of the Fabry-Pérot mode varies between 6800 and 9700. The spatial resolution of the instrument is of the order of 80 $^{\prime\prime}$ (Swinyard et al. 1996). See the ISO Handbook, Volume IV: LWS-The Long Wavelength Spectrometer and Clegg et al. (1996) for details.

The data were reduced using the standard pipeline 7. Data reduction was done similar to the SWS data, using the ISAP and LIA (version 7.3) software. Glitches due to cosmic rays were rejected and for every observation (TDT number) the line fluxes were measured. As for the SWS data, line fluxes of the same lines of spectra for each of our positions (see Table1) were averaged, again also excluding lines with FWHM significantly smaller than the instrumental profile. The FP data reduction was done by standard processing and we used associated LWS01 grating scans for optimizing the dark current. Afterwards the continuum was aligned horizontally in an interactive mode.

L1448