Table A.1: Log of the observations used.
Transition Observing ISO LWS Spectral Repeated

Mode TDT detector resolution scans

Number (km s^-1)

¹⁶OH

$^{2}\Pi_{3/2}~J=5/2$ -3/2 (119 $\mu$ m) L03 50601013 LW2 33 3

$^{2}\Pi _{1/2}$ - $^{2}\Pi _{3/2}$ L03 50400823 SW2 61 3

J=3/2-3/2 (53 $\mu$ m) L03 50601013 SW2 61 3

L03 50700707 SW2 61 3

L03 50800317 SW2 61 3

$^{2}\Pi _{1/2}$ - $^{2}\Pi _{3/2}$ L03 50900521 SW5 40 3

J=1/2-3/2 (79 $\mu$ m) L03 50600814 SW5 40 3

L03 50600603 SW4 40 3

L03 50700208 SW4 40 3

L03 83800606 SW4 40 4

L03 50600506 SW4 40 3

¹⁸OH

$^{2}\Pi_{3/2}~J=5/2$ -3/2 (120 $\mu$ m) L03 50601013 LW2 33 3

L03 50700610 LW2 33 3

L04 49401705 LW2 33 15

L04 46201118 LW2 33 11

L04 46900332 LW2 33 14

**Table A.1:** Log of the observations used.
Transition	Observing	ISO	LWS	Spectral	Repeated
	Mode	TDT	detector	resolution	scans
		Number		(km s^-1)
¹⁶OH
$^{2}\Pi_{3/2}~J=5/2$ -3/2 (119 $\mu$ m)	L03	50601013	LW2	33	3
$^{2}\Pi _{1/2}$ - $^{2}\Pi _{3/2}$	L03	50400823	SW2	61	3
J=3/2-3/2 (53 $\mu$ m)	L03	50601013	SW2	61	3
	L03	50700707	SW2	61	3
	L03	50800317	SW2	61	3
$^{2}\Pi _{1/2}$ - $^{2}\Pi _{3/2}$	L03	50900521	SW5	40	3
J=1/2-3/2 (79 $\mu$ m)	L03	50600814	SW5	40	3
	L03	50600603	SW4	40	3
	L03	50700208	SW4	40	3
	L03	83800606	SW4	40	4
	L03	50600506	SW4	40	3
¹⁸OH
$^{2}\Pi_{3/2}~J=5/2$ -3/2 (120 $\mu$ m)	L03	50601013	LW2	33	3
	L03	50700610	LW2	33	3
	L04	49401705	LW2	33	15
	L04	46201118	LW2	33	11
	L04	46900332	LW2	33	14

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observations and data reduction
	3 Results
	4 Modelling of OH in the line of sight
	5 ¹⁶OH/¹⁸OH ratio
	6 Comparison with other species
	7 Summary
	Appendix A: Observations and wavelengths
	References