Table 1: Log of the observations. The instruments and telescopes, filter names and central wavelengths, full width at half-maximum ( FWHM) of point sources, final useful field of view, total integration times and the dates of the observations are given.
Instrument Wavelength FWHM Field Integr. Date

[ $\mu$ m] [ $^{\prime\prime}$ ] of View time [s]

ISAAC UT1/VLT 1.2 (Js) 0.6'' 4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime$ 25 843.2 1st May 1999

ISAAC UT1/VLT 1.6 (H) 0.6'' 4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime25$ 1757.8 1st May 1999

ISAAC UT1/VLT 2.2 (Ks) 0.4'' 4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime25$ 2636.7 10th April 1999

ISAAC UT1/VLT 3.78 (L) 0.5'' 15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$ 237.6 1st June 2001

ISAAC UT1/VLT 4.07 (Br $\alpha$ ) 0.6'' 15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$ 431.2 1st June 2001

ISAAC UT1/VLT 4.66 (M(nb)) 0.5'' 15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$ 415.8 1st June 2001

TIMMI2/3.6 m 4.6 (M) 0.6'' 40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$ 424 14th March 2001

TIMMI2/3.6 m 11.9 (N11.9) 0.8'' 40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$ 807 14th March 2001

TIMMI2/3.6 m 12.9 (N12.9) 0.8'' 40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$ 1451 14th March 2001

TIMMI2/3.6 m 20 (Q) $1\hbox{$.\!\!^{\prime\prime}$ }4$ 40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$ 1008 14th March 2001

TIMMI2/3.6 m N-Spectr. 0.8'' 3 $^{\prime\prime}$ $\times$ 60 $^{\prime\prime}$ 510 14th March 2001

SIMBA/SEST 1200 24'' 9 $.\hskip-2pt^\prime$ 3 $\times$ 15 $^\prime$ 100 16th July 2003

**Table 1:** Log of the observations. The instruments and telescopes, filter names and central wavelengths, full width at half-maximum ( *FWHM*) of point sources, final useful field of view, total integration times and the dates of the observations are given.
Instrument	Wavelength	FWHM	Field	Integr.	Date
	[ $\mu$ m]	[ $^{\prime\prime}$ ]	of View	time [s]
ISAAC UT1/VLT	1.2 (Js)	0.6''	4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime$ 25	843.2	1st May 1999
ISAAC UT1/VLT	1.6 (H)	0.6''	4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime25$	1757.8	1st May 1999
ISAAC UT1/VLT	2.2 (Ks)	0.4''	4 $.\hskip-2pt^\prime25 \times 4.\hskip-2pt^\prime25$	2636.7	10th April 1999
ISAAC UT1/VLT	3.78 (L)	0.5''	15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$	237.6	1st June 2001
ISAAC UT1/VLT	4.07 (Br $\alpha$ )	0.6''	15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$	431.2	1st June 2001
ISAAC UT1/VLT	4.66 (M(nb))	0.5''	15 $^{\prime\prime}$ $\times$ 15 $^{\prime\prime}$	415.8	1st June 2001
TIMMI2/3.6 m	4.6 (M)	0.6''	40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$	424	14th March 2001
TIMMI2/3.6 m	11.9 (N11.9)	0.8''	40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$	807	14th March 2001
TIMMI2/3.6 m	12.9 (N12.9)	0.8''	40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$	1451	14th March 2001
TIMMI2/3.6 m	20 (Q)	$1\hbox{$.\!\!^{\prime\prime}$ }4$	40 $^{\prime\prime}$ $\times$ 40 $^{\prime\prime}$	1008	14th March 2001
TIMMI2/3.6 m	N-Spectr.	0.8''	3 $^{\prime\prime}$ $\times$ 60 $^{\prime\prime}$	510	14th March 2001
SIMBA/SEST	1200	24''	9 $.\hskip-2pt^\prime$ 3 $\times$ 15 $^\prime$	100	16th July 2003

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observations and data reduction
	3 Results
	4 Global picture and summary
	References