Table 3: Molecular column densities and abundances at 3 different positions of the PDR named "Cloud'', "IR peak'' and "IR edge''. Equatorial offsets refer to the Mosaic 2 map center given in Table 1. $(\delta x, \delta y)$ offsets refer to the coordinate system defined in Fig. 3. H₂ column densities have been derived from the 1.2 $\ensuremath{~ \ensuremath{{\rm mm}}}$ dust continuum emission using a dust temperature range of 20 to 40 $\ensuremath{~ \ensuremath{{\rm K}}}$ for the "Cloud'' position and 40 to 80 $\ensuremath{~ \ensuremath{{\rm K}}}$ for the IR positions. Others column densities used LVG models with a representative set of densities and kinetic temperature. 1- $\sigma$ uncertainties thus reflect the systematics due to the approximate knowledge of density and kinetic temperature. Abundances are computed with respect to the number of protons, i.e. $[{\rm X}] = 0.5~N({\rm X})/N(\mbox{H$_2$ })$ .
$\delta$ RA $\delta$ Dec $\delta x$ $\delta y$

Cloud +6'' -4'' +24.9'' -5.3''

IR peak -6'' -4'' +12.2'' -2.4''

IR edge -12'' -4'' +7.4'' -1.0''

**Table 3:** Molecular column densities and abundances at 3 different positions of the PDR named "Cloud'', "IR peak'' and "IR edge''. Equatorial offsets refer to the Mosaic 2 map center given in Table 1. $(\delta x, \delta y)$ offsets refer to the coordinate system defined in Fig. 3. H₂ column densities have been derived from the 1.2 $\ensuremath{~ \ensuremath{{\rm mm}}}$ dust continuum emission using a dust temperature range of 20 to 40 $\ensuremath{~ \ensuremath{{\rm K}}}$ for the "Cloud'' position and 40 to 80 $\ensuremath{~ \ensuremath{{\rm K}}}$ for the IR positions. Others column densities used LVG models with a representative set of densities and kinetic temperature. 1- $\sigma$ uncertainties thus reflect the systematics due to the approximate knowledge of density and kinetic temperature. Abundances are computed with respect to the number of protons, i.e. $[{\rm X}] = 0.5~N({\rm X})/N(\mbox{H$_2$ })$ .
	$\delta$ RA	$\delta$ Dec	$\delta x$	$\delta y$
Cloud	+6''	-4''	+24.9''	-5.3''
IR peak	-6''	-4''	+12.2''	-2.4''
IR edge	-12''	-4''	+7.4''	-1.0''

Quantity Unit Cloud IR peak IR edge

$S_{1.2\ensuremath{~ \ensuremath{{\rm mm}}} }$ mJy/Beam $38 \pm 2$ $35 \pm 2$ $12\pm 2$

$N(\mbox{H$_2$ })$ 10²¹ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$ $27 \pm 9.5$ $10.5 \pm 4$ $3.6\pm 1.7$

$N(\mbox{C$^{18}$ O})$ 10¹⁵ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$ $5.8 \pm 0.5$ $4 \pm 0.5$ $1\pm 0.3$

$N(\mbox{CCH})$ 10¹³ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$ $5.5 \pm 1$ $30 \pm 5$ $11\pm 3$

$N(\mbox{c-C$_3$ H$_2$ })$ 10¹² $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$ $2.3 \pm 0.7$ $24 \pm 10$ $9.5\pm 5$

$N(\mbox{C$_4$ H})$ 10¹² $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$ $20 \pm 10$ $40 \pm 10$ $37\pm 10$

Quantity Unit Cloud IR peak IR edge

$[\mbox{C$^{18}$ O}]$ 10^-7 1.07 1.9 1.4

$[\mbox{CCH}]$ 10^-8 0.10 1.4 1.5

$[\mbox{c-C$_3$ H$_2$ }]$ 10^-10 0.43 11.4 13.2

$[\mbox{C$_4$ H}]$ 10^-9 0.37 1.9 5.2

	1 Introduction
	2 Observations and data reduction
	3 Results
	4 Discussion
	5 Summary and conclusions
	References

Quantity	Unit	Cloud	IR peak	IR edge
$S_{1.2\ensuremath{~ \ensuremath{{\rm mm}}} }$	mJy/Beam	$38 \pm 2$	$35 \pm 2$	$12\pm 2$
$N(\mbox{H$_2$ })$	10²¹ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$	$27 \pm 9.5$	$10.5 \pm 4$	$3.6\pm 1.7$
$N(\mbox{C$^{18}$ O})$	10¹⁵ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$	$5.8 \pm 0.5$	$4 \pm 0.5$	$1\pm 0.3$
$N(\mbox{CCH})$	10¹³ $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$	$5.5 \pm 1$	$30 \pm 5$	$11\pm 3$
$N(\mbox{c-C$_3$ H$_2$ })$	10¹² $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$	$2.3 \pm 0.7$	$24 \pm 10$	$9.5\pm 5$
$N(\mbox{C$_4$ H})$	10¹² $\ensuremath{~ \ensuremath{{\rm cm^{-2}}}}$	$20 \pm 10$	$40 \pm 10$	$37\pm 10$