2 X-ray data reduction

The previously known young stars associated with the CrA dark cloud are located in a small, $\sim 126~{\rm deg} ^{2}$ area around R CrA near $\alpha _{2000} = 19^{\rm h}$ and $\delta _{2000} = -37 ^{\circ}$. Because we also expect to find previously unknown young stars around the dark cloud, we investigated the area $\alpha _{2000} = 18^{\rm h}~35^{\rm m}$ to $19^{\rm h}~38^{\rm m}$ and $\delta _{2000} = -41^{\circ}$ to $-33^{\circ}$.

We reduced all RASS II data pertaining to that area with the Extended Scientific Analysis Software (EXSAS, Zimmermann et al. 1994) version 98APR running under ESO-MIDAS version 97NOV. We performed standard local and map source detection in the bands soft (0.1 to $0.4~{\rm keV}$), hard 1 (0.5 to $0.9~{\rm keV}$), hard 2 (0.9 to $2.0~{\rm keV}$), hard (0.5 to $2.0~{\rm keV}$), and broad (0.1 to $2.4~{\rm keV}$), as described in detail in Neuhäuser et al. (1995). After merging the source lists, each source was again tested in the above mentioned five bands by a maximum likelihood source detection algorithm. Following Neuhäuser et al. (1995) we accept only sources with $ML \ge 7.4$ corresponding to $\sim 3.5~\sigma$ as real.

   

Table 2: X-ray data for our sample. Listed are all X-ray sources detected in the ROSAT All-Sky Survey sorted by right ascension. We list a running number (used in other tables for cross-reference), the ROSAT source designation, the X-ray source position (J2000.0), the maximum likelihood of existence ML, the hardness ratios with errors, the (background subtracted and vignetting corrected) number of counts in the broad band (0.1 to $2.4~{\rm keV}$) with errors, the exposure time in seconds, and $\log ECF$ for the energy conversion factor in counts ${\rm erg^{-1}~cm^{2}}$

No.	Designation	$\alpha _{2000}$ (X-ray) $\delta _{2000}$		ML	HR 1	HR 2	Counts	Exp. [s]	$\log ECF$
1	RXJ1835.1-3404	18:35:08.0	-34:04:20.0	10.2	$\ge 0.61$	$0.30 \pm 0.36$	8.9$~\pm~$ 4.0	147.2	-10.87
2	RXJ1835.3-3927	18:35:21.5	-39:27:13.3	8.1	$0.15 \pm 0.49$	$\ge 0.10$	7.1$~\pm~$ 3.2	124.3	-11.04
3	RXJ1835.7-3259	18:35:47.0	-32:59:41.5	1240.1	$0.93 \pm 0.02$	$0.53 \pm 0.05$	364.0$~\pm~$19.6	163.0	-10.88
4	RXJ1835.8-3813	18:35:49.2	-38:13:24.1	9.8	$0.77 \pm 0.41$	$0.02 \pm 0.44$	11.7$~\pm~$ 4.3	139.4	-10.91
5	RXJ1835.8-4046	18:35:53.4	-40:46:23.5	10.2	$\ge 0.27$	$\ge 0.43$	3.6$~\pm~$ 2.3	125.7	-10.87
6	RXJ1835.9-3525	18:35:58.3	-35:25:35.5	7.7	$0.77 \pm 0.44$	$\ge 0.42$	6.1$~\pm~$ 3.4	143.3	-10.91
7	RXJ1836.3-4010	18:36:18.7	-40:10:20.2	13.1	$-0.65 \pm 0.40$	$\le 0.19$	11.2$~\pm~$ 4.0	131.5	-11.31
8	RXJ1836.6-3451	18:36:40.6	-34:51:33.5	13.2	$\ge 0.44$	$0.28 \pm 0.42$	9.4$~\pm~$ 3.9	139.1	-10.87
9	RXJ1837.3-3442	18:37:18.2	-34:42:39.0	13.1	$0.25 \pm 0.40$	$0.05 \pm 0.54$	9.2$~\pm~$ 3.5	133.2	-11.02
10	RXJ1838.2-3838	18:38:17.1	-38:38:12.9	11.8	$\ge 0.47$	$0.31 \pm 0.41$	8.0$~\pm~$ 3.3	142.1	-10.87
11	RXJ1838.3-3523	18:38:20.2	-35:23:32.6	10.3	$-0.67 \pm 0.52$	$\le 0.42$	9.4$~\pm~$ 3.8	140.0	-11.32
12	RXJ1839.0-3705	18:39:05.8	-37:05:46.8	21.6	$0.84 \pm 0.24$	$-0.03 \pm 0.31$	13.4$~\pm~$ 4.2	139.0	-10.89
13	RXJ1839.0-3726	18:39:05.9	-37:26:36.0	12.3	$0.78 \pm 0.21$	$-0.30 \pm 0.39$	9.7$~\pm~$ 3.9	142.1	-10.90
14	RXJ1839.2-3854	18:39:16.1	-38:54:13.8	9.2	$\ge 0.18$	$\ge 0.40$	3.3$~\pm~$ 2.5	135.4	-10.87
15	RXJ1839.7-3458	18:39:46.8	-34:58:58.2	7.8	$\ge 0.55$	$0.51 \pm 0.35$	5.8$~\pm~$ 3.2	167.4	-10.87
16	RXJ1840.1-3640	18:40:09.5	-36:40:09.1	7.9	$0.24 \pm 0.40$	$0.08 \pm 0.52$	8.6$~\pm~$ 3.6	154.6	-11.02
17	RXJ1840.6-3728	18:40:38.3	-37:28:44.3	13.0	$\ge 0.67$	$0.29 \pm 0.36$	8.6$~\pm~$ 3.6	150.6	-10.87
18	RXJ1840.6-3612	18:40:39.7	-36:12:14.1	7.8	$0.34 \pm 0.37$	$-0.01 \pm 0.48$	11.1$~\pm~$ 4.2	150.4	-10.99
19	RXJ1840.8-3547	18:40:53.8	-35:47:06.2	32.7	$-0.13 \pm 0.25$	$-0.19 \pm 0.38$	20.2$~\pm~$ 5.0	147.3	-11.12
20	RXJ1840.9-3350	18:40:55.1	-33:50:52.5	14.9	$0.28 \pm 0.30$	$0.38 \pm 0.33$	16.4$~\pm~$ 5.1	180.2	-11.01
21	RXJ1841.2-3821	18:41:13.5	-38:21:55.9	9.1	$\le -0.49$		5.7$~\pm~$ 3.1	151.9	-11.52
22	RXJ1841.5-3508	18:41:34.2	-35:08:27.7	11.2	$0.15 \pm 0.38$	$-0.28 \pm 0.53$	9.5$~\pm~$ 3.8	154.7	-11.04
23	RXJ1841.8-3525	18:41:49.7	-35:25:44.3	58.2	$0.47 \pm 0.18$	$-0.14 \pm 0.24$	26.6$~\pm~$ 5.6	140.0	-10.97
24	RXJ1842.1-3732	18:42:12.0	-37:32:33.0	9.4	$0.05 \pm 0.38$	$-0.09 \pm 0.53$	9.7$~\pm~$ 3.8	141.1	-11.07
25	RXJ1842.8-3845	18:42:48.6	-38:45:28.3	8.7	$\ge 0.40$	$0.46 \pm 0.45$	8.7$~\pm~$ 3.6	137.4	-10.87
26	RXJ1842.9-3451	18:42:58.2	-34:51:00.3	7.6	$0.95 \pm 0.50$	$\ge 0.22$	3.7$~\pm~$ 2.4	154.3	-10.87
27	RXJ1842.9-3532	18:42:58.4	-35:32:34.6	21.7	$0.90 \pm 0.24$	$0.29 \pm 0.34$	10.9$~\pm~$ 3.9	135.3	-10.88
28	RXJ1843.0-3331	18:43:05.2	-33:31:07.6	8.1	$0.35 \pm 0.40$	$0.14 \pm 0.49$	8.7$~\pm~$ 3.9	191.5	-10.99
29	RXJ1843.4-3314	18:43:24.5	-33:14:31.4	11.8	$-0.51 \pm 0.35$	$\le 0.32$	14.3$~\pm~$ 5.0	194.2	-11.25
30	RXJ1844.3-3541	18:44:19.5	-35:41:43.5	30.0	$0.70 \pm 0.19$	$0.12 \pm 0.26$	24.5$~\pm~$ 5.8	149.5	-10.92
31	RXJ1844.5-3723	18:44:31.1	-37:23:59.8	43.4	$0.62 \pm 0.20$	$0.18 \pm 0.26$	23.2$~\pm~$ 5.2	141.1	-10.94
32	RXJ1844.5-3739	18:44:31.3	-37:39:13.9	10.4	$0.53 \pm 0.46$	$\ge 0.24$	6.9$~\pm~$ 3.3	134.9	-10.95
33	RXJ1844.7-3313	18:44:43.4	-33:13:56.1	8.9	$0.83 \pm 0.31$	$0.78 \pm 0.47$	7.4$~\pm~$ 3.8	206.1	-10.90
34	RXJ1844.7-3450	18:44:45.9	-34:50:55.2	7.9	$0.68 \pm 0.65$	$\ge 0.41$	4.8$~\pm~$ 2.9	185.1	-10.92
35	RXJ1845.1-3324	18:45:10.4	-33:24:26.3	10.6	$-0.28 \pm 0.38$	$0.20 \pm 0.62$	9.6$~\pm~$ 3.9	200.1	-11.16
36	RXJ1845.5-3750	18:45:34.4	-37:50:24.3	57.7	$0.59 \pm 0.15$	$0.28 \pm 0.18$	39.6$~\pm~$ 6.9	143.7	-10.94
37	RXJ1846.3-3552	18:46:18.9	-35:52:34.0	7.9	$\le -0.34$		5.6$~\pm~$3.0	161.1	-11.52
38	RXJ1846.7-3604	18:46:44.3	-36:04:40.4	8.0	$\ge -0.09$	$0.06 \pm 0.59$	5.1$~\pm~$ 2.9	143.7	-10.87
39	RXJ1846.7-3636	18:46:46.2	-36:36:21.3	29.2	$0.07 \pm 0.27$	$0.20 \pm 0.36$	19.1$~\pm~$ 4.9	142.0	-11.06
40	RXJ1846.8-3911	18:46:53.3	-39:11:10.3	7.8	$0.45 \pm 0.42$	$-0.12 \pm 0.49$	8.9$~\pm~$ 3.6	125.3	-10.97
41	RXJ1846.9-3503	18:46:58.0	-35:03:59.4	9.1	$0.84 \pm 0.33$	$\le -0.59$	7.9$~\pm~$ 3.8	176.3	-10.89
42	RXJ1847.2-3709	18:47:14.3	-37:09:43.3	8.6	$0.47 \pm 0.42$	$\le -0.30$	6.5$~\pm~$ 3.2	136.3	-10.97
43	RXJ1847.5-3642	18:47:32.9	-36:42:43.9	9.6	$0.93 \pm 0.44$	$0.13 \pm 0.52$	4.6$~\pm~$ 2.3	136.0	-10.88
44	RXJ1847.7-3606	18:47:46.5	-36:06:12.4	29.7	$\ge 0.68$	$0.14 \pm 0.28$	15.7$~\pm~$ 4.4	154.3	-10.87
45	RXJ1847.7-4024	18:47:46.9	-40:24:14.2	69.8	$0.00 \pm 0.19$	$0.35 \pm 0.24$	36.7$~\pm~$ 6.5	130.2	-11.08
46	RXJ1847.8-3828	18:47:51.9	-38:28:45.9	7.4	$\ge 0.19$	$\ge 0.23$	2.2$~\pm~$ 1.7	122.5	-10.87
47	RXJ1848.2-3415	18:48:12.1	-34:15:41.3	8.2	$0.42 \pm 0.39$	$-0.16 \pm 0.47$	9.4$~\pm~$ 4.0	202.0	-10.98
48	RXJ1848.6-3458	18:48:36.1	-34:58:58.0	8.0	$0.08 \pm 0.59$	$0.22 \pm 0.85$	8.7$~\pm~$ 3.8	200.2	-11.06
49	RXJ1849.0-3734	18:49:02.0	-37:34:22.7	9.6	$\ge 0.40$	$-0.44 \pm 0.41$	6.0$~\pm~$ 3.0	157.8	-10.87
50	RXJ1849.1-3546	18:49:08.7	-35:46:41.7	45.0	$0.71 \pm 0.17$	$0.56 \pm 0.20$	22.5$~\pm~$ 5.2	193.1	-10.92
51	RXJ1851.4-3455	18:51:26.1	-34:55:31.6	8.1	$\ge 0.39$	$-0.45 \pm 0.48$	5.3$~\pm~$ 3.0	211.0	-10.87
52	RXJ1852.1-3607	18:52:10.2	-36:07:24.9	7.8	$0.19 \pm 0.39$	$-0.57 \pm 0.43$	9.4$~\pm~$ 3.8	171.9	-11.03

Table 2. continued

No.	Designation	$\alpha _{2000}$ (X-ray) $\delta _{2000}$		ML	HR 1	HR 2	Counts	Exp. [s]	$\log ECF$
53	RXJ1852.3-3700	18:52:18.2	-37:00:20.4	36.3	$0.90 \pm 0.13$	$0.54 \pm 0.25$	14.7$~\pm~$ 4.3	155.5	-10.88
54	RXJ1852.4-3730	18:52:25.6	-37:30:32.4	54.4	$-0.41 \pm 0.19$	$-0.26 \pm 0.38$	29.4$~\pm~$ 6.0	152.8	-11.21
55	RXJ1853.1-3609	18:53:06.5	-36:09:54.7	55.5	$0.33 \pm 0.18$	$0.40 \pm 0.22$	37.1$~\pm~$ 6.8	190.8	-11.00
56	RXJ1853.4-4020	18:53:26.3	-40:20:02.8	9.2	$-0.18 \pm 0.49$	$\le 0.01$	7.7$~\pm~$ 3.4	147.6	-11.13
57	RXJ1853.5-3544	18:53:36.0	-35:44:32.7	9.4	$\ge 0.34$	$0.10 \pm 0.48$	6.4$~\pm~$ 3.3	214.1	-10.87
58	RXJ1854.4-4010	18:54:25.7	-40:10:21.7	9.3	$\ge 0.32$	$0.40 \pm 0.48$	7.1$~\pm~$ 3.4	154.8	-10.87
59	RXJ1854.4-3738	18:54:28.2	-37:38:39.7	7.7	$\ge 0.37$	$0.39 \pm 0.44$	6.0$~\pm~$ 3.1	173.8	-10.87
60	RXJ1854.5-3823	18:54:34.3	-38:23:22.2	8.5	$-0.31 \pm 0.42$	$\le -0.27$	13.0$~\pm~$ 4.6	161.7	-11.18
61	RXJ1854.9-3600	18:54:59.4	-36:00:26.0	8.9	$\ge 0.40$	$-0.47 \pm 0.44$	9.5$~\pm~$ 4.0	232.8	-10.87
62	RXJ1855.5-3806	18:55:32.5	-38:06:41.2	12.7	$\ge 0.58$	$0.76 \pm 0.32$	8.4$~\pm~$ 4.0	171.9	-10.87
63	RXJ1856.5-3754	18:56:35.1	-37:54:32.7	2643.8	$-0.92 \pm 0.02$	$-0.94 \pm 0.16$	637.3$~\pm~$25.5	166.8	-11.46
64	RXJ1856.6-3545	18:56:43.7	-35:45:23.1	8.9	$\ge 0.07$	$0.22 \pm 0.28$	4.7$~\pm~$ 2.7	216.0	-10.87
65	RXJ1856.7-4021	18:56:46.2	-40:21:10.7	12.0	$\ge 0.52$	$0.61 \pm 0.37$	7.0$~\pm~$ 3.5	166.0	-10.87
66	RXJ1857.3-3635	18:57:19.8	-36:35:49.3	10.6	$-0.45 \pm 0.38$	$-0.78 \pm 1.33$	11.4$~\pm~$ 4.2	211.7	-11.23
67	RXJ1857.3-3554	18:57:22.4	-35:54:19.4	10.0	$\le -0.45$	$\ge -0.65$	6.7$~\pm~$ 3.3	244.5	-11.52
68	RXJ1857.5-3732	18:57:33.7	-37:32:57.3	10.5	$0.78 \pm 0.37$	$0.95 \pm 0.37$	5.8$~\pm~$ 2.9	176.8	-10.90
69	RXJ1857.9-3651	18:58:00.1	-36:51:10.7	8.5	$\le -0.43$	$\ge -0.83$	8.3$~\pm~$ 3.8	225.4	-11.52
70	RXJ1858.0-3640	18:58:05.3	-36:40:57.2	8.1	$-0.01 \pm 0.41$	$-0.44 \pm 0.47$	10.3$~\pm~$ 4.3	236.1	-11.08
71	RXJ1858.4-3446	18:58:29.4	-34:46:53.2	32.1	$0.83 \pm 0.16$	$-0.32 \pm 0.23$	27.8$~\pm~$ 6.4	312.3	-10.90
72	RXJ1858.6-3630	18:58:40.4	-36:30:38.8	12.3	$-0.17 \pm 0.35$	$0.42 \pm 0.45$	12.5$~\pm~$ 4.6	257.0	-11.13
73	RXJ1858.7-3706	18:58:43.5	-37:06:18.3	25.1	$-0.19 \pm 0.27$	$0.22 \pm 0.49$	20.9$~\pm~$ 5.3	229.4	-11.14
74	RXJ1859.0-4051	18:59:01.1	-40:51:19.5	8.5	$\ge 0.14$	$\le -0.23$	6.0$~\pm~$ 3.2	154.6	-10.87
75	RXJ1859.3-3406	18:59:21.7	-34:06:09.9	7.5	$\ge 0.55$	$-0.16 \pm 0.42$	6.1$~\pm~$ 3.7	300.1	-10.87
76	RXJ1900.6-3810	19:00:38.9	-38:10:19.5	14.2	$0.99 \pm 0.15$	$0.27 \pm 0.30$	13.4$~\pm~$ 4.9	234.9	-10.87
77	RXJ1900.8-3453	19:00:51.4	-34:53:08.0	7.9	$0.99 \pm 0.44$	$0.10 \pm 0.39$	9.9$~\pm~$ 4.3	296.8	-10.87
78	RXJ1900.9-3928	19:00:59.6	-39:28:55.6	10.3	$\ge 0.54$	$-0.43 \pm 0.35$	8.1$~\pm~$ 3.8	190.4	-10.87
79	RXJ1901.1-3333	19:01:08.8	-33:33:40.8	8.9	$\ge 0.39$	$\le -0.35$	3.6$~\pm~$ 2.4	233.9	-10.87
80	RXJ1901.1-3648	19:01:09.2	-36:48:01.7	9.8	$0.42 \pm 0.39$	$0.44 \pm 0.42$	9.7$~\pm~$ 4.0	272.1	-10.98
81	RXJ1901.4-4022	19:01:24.6	-40:22:31.9	11.3	$0.63 \pm 0.63$	$-0.17 \pm 0.46$	11.0$~\pm~$ 4.2	188.3	-10.93
82	RXJ1901.4-3422	19:01:26.8	-34:22:44.8	48.4	$0.11 \pm 0.19$	$-0.40 \pm 0.23$	37.7$~\pm~$ 7.1	295.0	-11.05
83	RXJ1901.5-3700	19:01:31.4	-37:00:55.1	37.7	$0.83 \pm 0.17$	$-0.06 \pm 0.22$	26.8$~\pm~$ 6.1	268.0	-10.90
84	RXJ1901.6-3652	19:01:38.9	-36:52:55.0	38.3	$0.80 \pm 0.18$	$0.54 \pm 0.20$	24.6$~\pm~$ 5.8	278.8	-10.90
85	RXJ1901.6-3644	19:01:39.0	-36:44:52.4	27.1	$\ge 0.61$	$0.95 \pm 0.15$	15.2$~\pm~$ 4.8	279.1	-10.87
86	RXJ1902.0-3822	19:02:03.1	-38:22:02.4	8.9	$0.15 \pm 0.42$	$\ge 0.21$	8.3$~\pm~$ 3.5	237.5	-11.04
87	RXJ1902.0-3707	19:02:03.1	-37:07:47.7	22.6	$0.71 \pm 0.21$	$0.58 \pm 0.24$	17.5$~\pm~$ 4.8	268.1	-10.92
88	RXJ1902.3-3310	19:02:20.0	-33:10:45.8	8.0	$-0.82 \pm 0.47$		8.1$~\pm~$ 3.7	187.4	-11.40
89	RXJ1902.3-3655	19:02:22.7	-36:55:42.8	7.5	$\ge 0.07$	$0.76 \pm 0.38$	4.8$~\pm~$ 2.8	282.5	-10.87
90	RXJ1902.3-3922	19:02:22.8	-39:22:11.2	9.5	$-0.32 \pm 0.44$	$-0.64 \pm 0.85$	9.4$~\pm~$ 3.8	204.3	-11.18
91	RXJ1902.4-3617	19:02:24.0	-36:17:53.5	7.6	$\ge 0.54$	$-0.06 \pm 0.48$	4.1$~\pm~$ 2.7	306.9	-10.87
92	RXJ1902.5-3504	19:02:31.6	-35:04:58.8	9.5	$\le -0.58$		7.0$~\pm~$ 3.6	305.2	-11.52
93	RXJ1902.7-3418	19:02:45.6	-34:18:36.0	8.8	$\ge 0.47$	$0.67 \pm 0.46$	5.3$~\pm~$ 3.3	288.8	-10.87
94	RXJ1903.0-3906	19:03:01.6	-39:06:09.4	12.9	$\ge 0.50$	$0.20 \pm 0.37$	10.4$~\pm~$ 4.1	222.5	-10.87
95	RXJ1903.0-4009	19:03:03.4	-40:09:09.7	18.6	$0.63 \pm 0.34$	$0.03 \pm 0.34$	13.6$~\pm~$ 4.3	194.3	-10.93
96	RXJ1904.0-3817	19:04:01.7	-38:17:05.0	7.7	$\ge 0.28$	$\le -0.39$	4.4$~\pm~$ 2.8	286.9	-10.87
97	RXJ1904.0-3804	19:04:04.0	-38:04:19.0	10.2	$-0.64 \pm 0.39$	$-0.76 \pm 1.61$	13.5$~\pm~$ 4.8	299.3	-11.31
98	RXJ1904.0-3824	19:04:04.7	-38:24:56.8	7.4	$\le -0.14$		5.2$~\pm~$ 3.0	293.0	-11.52
99	RXJ1904.3-3835	19:04:23.7	-38:35:15.9	10.6	$\ge 0.42$	$\ge 0.36$	7.4$~\pm~$ 3.8	289.8	-10.87
100	RXJ1904.5-3307	19:04:34.0	-33:07:16.0	8.0	$0.91 \pm 0.38$	$0.27 \pm 0.39$	7.9$~\pm~$ 3.7	115.6	-10.88
101	RXJ1904.5-4028	19:04:34.4	-40:28:31.9	7.5	$\le -0.29$	$\le 0.77$	7.4$~\pm~$ 3.8	218.5	-11.52
102	RXJ1904.6-4048	19:04:36.4	-40:48:24.2	8.9	$\ge 0.42$	$-0.15 \pm 0.44$	7.3$~\pm~$ 3.4	211.3	-10.87
103	RXJ1904.7-3604	19:04:43.8	-36:04:58.5	17.8	$0.60 \pm 0.26$	$0.33 \pm 0.29$	17.6$~\pm~$ 5.1	326.7	-10.94
104	RXJ1905.0-3817	19:05:04.9	-38:17:46.3	9.6	$0.09 \pm 0.36$	$-0.04 \pm 0.49$	11.7$~\pm~$ 4.3	313.2	-11.06
105	RXJ1905.0-3629	19:05:05.2	-36:29:14.0	8.8	$0.86 \pm 0.74$	$\le -0.50$	6.8$~\pm~$ 3.6	332.1	-10.89
106	RXJ1905.3-3855	19:05:18.8	-38:55:15.1	12.1	$0.70 \pm 0.33$	$0.07 \pm 0.35$	17.5$~\pm~$ 5.1	304.2	-10.92
107	RXJ1905.3-4030	19:05:19.6	-40:30:59.1	8.5	$-0.34 \pm 0.36$	$-0.28 \pm 0.71$	12.3$~\pm~$ 4.5	247.9	-11.19
108	RXJ1906.4-3703	19:06:25.0	-37:03:34.9	25.2	$-0.80 \pm 0.25$	$\ge -0.10$	14.3$~\pm~$ 4.2	325.1	-11.39
109	RXJ1906.5-3932	19:06:31.9	-39:32:58.1	8.8	$-0.93 \pm 0.55$	$\le 0.06$	8.6$~\pm~$ 3.9	289.6	-11.47

Table 2. continued

No.	Designation	$\alpha _{2000}$ (X-ray) $\delta _{2000}$		ML	HR 1	HR 2	Counts	Exp. [s]	$\log ECF$
110	RXJ1906.8-3748	19:06:51.2	-37:48:40.3	12.8	$\le -0.55$		8.4$~\pm~$ 3.4	325.3	-11.52
111	RXJ1907.8-3923	19:07:50.8	-39:23:39.8	74.9	$\ge 0.82$	$0.33 \pm 0.18$	28.8$~\pm~$ 5.9	294.9	-10.87
112	RXJ1909.6-3949	19:09:40.9	-39:49:37.6	35.1	$0.52 \pm 0.22$	$0.26 \pm 0.26$	20.4$~\pm~$ 5.0	322.2	-10.96
113	RXJ1909.8-3343	19:09:50.9	-33:43:17.9	10.6	$\le -0.31$		7.0$~\pm~$ 3.4	222.6	-11.52
114	RXJ1910.8-3854	19:10:48.8	-38:54:48.4	20.0	$-0.04 \pm 0.27$	$-0.42 \pm 0.36$	20.7$~\pm~$ 5.4	351.6	-11.09
115	RXJ1911.5-3434	19:11:34.8	-34:34:59.3	40.6	$0.68 \pm 0.17$	$0.13 \pm 0.24$	26.9$~\pm~$ 6.0	323.7	-10.92
116	RXJ1911.7-3641	19:11:47.4	-36:41:54.9	11.3	$-0.76 \pm 0.41$	$0.81 \pm 1.14$	10.3$~\pm~$ 3.9	320.2	-11.37
117	RXJ1912.6-3431	19:12:36.6	-34:31:40.5	16.7	$0.57 \pm 0.34$	$0.09 \pm 0.36$	13.8$~\pm~$ 4.5	322.2	-10.95
118	RXJ1913.0-3633	19:13:01.2	-36:33:04.4	22.2	$0.68 \pm 0.24$	$0.00 \pm 0.30$	16.4$~\pm~$ 4.7	319.0	-10.92
119	RXJ1913.1-3622	19:13:10.2	-36:22:06.1	8.6	$\ge 0.39$	$-0.59 \pm 0.38$	7.6$~\pm~$ 3.5	318.8	-10.87
120	RXJ1913.3-3530	19:13:21.8	-35:30:40.1	8.3	$\ge 0.27$	$\le -0.35$	4.7$~\pm~$ 2.8	317.9	-10.87
121	RXJ1913.6-3543	19:13:36.6	-35:43:10.1	11.7	$\ge 0.54$	$\le -0.39$	5.8$~\pm~$ 3.3	307.7	-10.87
122	RXJ1913.7-3303	19:13:46.3	-33:03:59.8	9.3	$0.51 \pm 0.32$	$-0.15 \pm 0.42$	10.8$~\pm~$ 4.1	194.9	-10.96
123	RXJ1913.8-3347	19:13:50.2	-33:47:49.1	13.9	$-0.06 \pm 0.38$	$0.36 \pm 0.55$	15.8$~\pm~$ 5.2	275.4	-11.10
124	RXJ1914.4-3532	19:14:28.9	-35:32:27.2	8.1	$\ge 0.14$	$\le -0.19$	7.5$~\pm~$ 3.6	292.3	-10.87
125	RXJ1914.6-3601	19:14:36.3	-36:01:12.9	8.0	$\le -0.37$		8.4$~\pm~$ 4.0	286.1	-11.52
126	RXJ1915.5-3759	19:15:32.2	-37:59:35.3	8.5	$\le -0.49$		4.6$~\pm~$ 2.7	316.6	-11.52
127	RXJ1915.5-3528	19:15:34.3	-35:28:45.2	7.8	$0.69 \pm 0.43$	$-0.42 \pm 0.36$	9.8$~\pm~$ 4.2	283.4	-10.92
128	RXJ1915.7-3321	19:15:46.7	-33:21:58.7	9.7	$\ge 0.37$	$-0.59 \pm 0.37$	5.7$~\pm~$ 2.9	228.0	-10.87
129	RXJ1915.9-3350	19:15:58.7	-33:50:47.7	9.3	$\ge 0.31$	$\le -0.50$	5.1$~\pm~$ 3.2	267.5	-10.87
130	RXJ1916.2-3548	19:16:13.1	-35:48:20.1	11.3	$0.57 \pm 0.25$	$-0.35 \pm 0.37$	13.6$~\pm~$ 4.6	283.9	-10.94
131	RXJ1916.5-3458	19:16:33.7	-34:58:55.7	9.2	$\le -0.35$	$\le 0.47$	9.2$~\pm~$ 4.1	292.7	-11.52
132	RXJ1916.9-4024	19:16:58.2	-40:24:32.0	7.8	$-0.85 \pm 0.45$	$\ge -0.50$	6.0$~\pm~$ 2.9	246.5	-11.42
133	RXJ1917.0-3331	19:17:04.0	-33:31:04.4	28.0	$\ge 0.63$	$0.77 \pm 0.19$	17.0$~\pm~$ 5.0	219.5	-10.87
134	RXJ1917.2-3931	19:17:12.9	-39:31:25.8	7.6	$\ge 0.20$	$\le -0.06$	4.1$~\pm~$ 2.5	287.9	-10.87
135	RXJ1917.4-3756	19:17:24.3	-37:56:55.4	122.6	$0.46 \pm 0.12$	$0.08 \pm 0.16$	58.1$~\pm~$ 8.2	310.7	-10.97
136	RXJ1917.8-3927	19:17:51.3	-39:27:33.4	7.8	$\ge 0.41$	$-0.16 \pm 0.47$	5.7$~\pm~$ 3.1	286.2	-10.87
137	RXJ1918.0-4000	19:18:00.7	-40:00:28.6	7.6	$0.25 \pm 0.46$	$\ge 0.24$	6.7$~\pm~$ 3.2	250.7	-11.02
138	RXJ1918.2-3823	19:18:12.9	-38:23:05.8	1044.6	$-0.08 \pm 0.06$	$0.20 \pm 0.08$	319.8$~\pm~$18.3	307.7	-11.10
139	RXJ1918.4-3913	19:18:25.1	-39:13:30.9	7.7	$0.62 \pm 0.37$	$\le -0.48$	7.8$~\pm~$ 3.6	299.9	-10.94
140	RXJ1919.4-4031	19:19:29.1	-40:31:34.7	9.0	$-0.02 \pm 0.40$	$0.51 \pm 0.56$	12.1$~\pm~$ 4.4	209.3	-11.09
141	RXJ1919.5-3639	19:19:31.5	-36:39:37.2	9.4	$-0.96 \pm 0.51$	$\le 0.61$	8.3$~\pm~$ 3.9	298.4	-11.49
142	RXJ1919.9-3924	19:19:55.3	-39:24:56.6	16.5	$-0.40 \pm 0.31$	$\ge 0.17$	14.8$~\pm~$ 4.7	306.5	-11.21
143	RXJ1919.9-4009	19:19:59.1	-40:09:22.0	7.5	$-0.52 \pm 0.36$	$-0.43 \pm 0.82$	10.4$~\pm~$ 4.1	252.7	-11.25
144	RXJ1920.6-3911	19:20:41.4	-39:11:29.6	7.9	$0.66 \pm 0.36$	$0.35 \pm 0.45$	7.3$~\pm~$ 3.3	314.8	-10.93
145	RXJ1920.9-3320	19:20:59.0	-33:20:06.7	9.5	$0.32 \pm 0.37$	$0.12 \pm 0.45$	10.4$~\pm~$ 4.0	257.8	-11.00
146	RXJ1921.1-4002	19:21:09.2	-40:02:14.4	9.6	$\le -0.55$		8.6$~\pm~$ 4.1	264.9	-11.52
147	RXJ1921.4-3459	19:21:28.9	-34:59:04.4	472.1	$-0.10 \pm 0.07$	$-0.04 \pm 0.11$	202.2$~\pm~$14.9	300.4	-11.11
148	RXJ1922.0-3549	19:22:01.8	-35:49:16.1	9.8	$\ge 0.54$	$-0.72 \pm 0.33$	7.8$~\pm~$ 4.0	311.7	-10.87
149	RXJ1922.4-3806	19:22:24.3	-38:06:13.6	8.3	$\ge 0.60$	$-0.06 \pm 0.45$	6.7$~\pm~$ 3.4	303.9	-10.87
150	RXJ1922.9-3545	19:22:55.3	-35:45:39.2	21.4	$\ge 0.68$	$\ge 0.53$	10.5$~\pm~$ 3.9	303.9	-10.87
151	RXJ1923.3-3658	19:23:18.9	-36:58:39.3	9.7	$-0.05 \pm 0.37$	$0.30 \pm 0.56$	10.2$~\pm~$ 4.0	320.7	-11.10
152	RXJ1923.6-3551	19:23:37.6	-35:51:39.8	8.7	$\ge 0.41$	$0.48 \pm 0.47$	6.2$~\pm~$ 3.2	298.5	-10.87
153	RXJ1923.8-3700	19:23:51.9	-37:00:08.2	7.6	$0.51 \pm 0.34$	$-0.02 \pm 0.51$	7.4$~\pm~$ 3.3	311.9	-10.96
154	RXJ1923.8-4036	19:23:53.3	-40:36:46.4	66.9	$-0.08 \pm 0.19$	$-0.35 \pm 0.27$	33.1$~\pm~$ 6.3	275.6	-11.10
155	RXJ1924.1-3333	19:24:09.9	-33:33:10.2	8.0	$0.74 \pm 0.40$	$0.32 \pm 0.42$	9.7$~\pm~$ 4.2	296.8	-10.91
156	RXJ1924.3-4008	19:24:20.2	-40:08:35.5	7.7	$0.02 \pm 0.46$	$\le -0.11$	10.0$~\pm~$4.3	309.0	-11.08
157	RXJ1924.4-3959	19:24:27.9	-39:59:29.1	10.3	$0.53 \pm 0.38$	$0.87 \pm 0.32$	6.9$~\pm~$ 3.2	307.9	-10.95
158	RXJ1924.5-3442	19:24:34.0	-34:42:34.6	20.5	$-0.29 \pm 0.31$	$0.95 \pm 0.47$	15.0$~\pm~$ 4.5	298.9	-11.17
159	RXJ1924.7-3601	19:24:47.3	-36:01:15.1	7.5	$-0.09 \pm 0.45$	$0.20 \pm 0.77$	7.7$~\pm~$ 3.5	297.7	-11.11
160	RXJ1925.0-3621	19:25:02.7	-36:21:39.1	10.1	$0.07 \pm 0.40$	$-0.22 \pm 0.54$	8.2$~\pm~$ 3.4	297.3	-11.06
161	RXJ1925.0-3549	19:25:03.9	-35:49:34.4	7.6	$\ge 0.39$	$0.60 \pm 0.32$	10.8$~\pm~$ 4.6	297.0	-10.87
162	RXJ1925.3-3413	19:25:21.4	-34:13:06.4	7.4	$\le -0.49$	$\le 0.88$	9.6$~\pm~$ 4.3	312.5	-11.52
163	RXJ1926.5-3426	19:26:31.8	-34:26:25.7	7.6	$\le -0.47$	$\ge -0.60$	6.8$~\pm~$ 3.5	300.9	-11.52
164	RXJ1927.1-3713	19:27:06.2	-37:13:42.2	14.6	$\ge 0.65$	$0.77 \pm 0.30$	10.2$~\pm~$ 4.0	316.9	-10.87
165	RXJ1927.4-3847	19:27:28.0	-38:47:06.9	28.3	$\ge 0.71$	$0.29 \pm 0.25$	17.3$~\pm~$ 5.0	307.7	-10.87
166	RXJ1927.9-3955	19:27:55.0	-39:55:03.8	7.9	$\le -0.44$	$\le 0.98$	5.5$~\pm~$3.0	325.6	-11.52

Table 2. continued

No.	Designation	$\alpha _{2000}$ (X-ray) $\delta _{2000}$		ML	HR 1	HR 2	Counts	Exp. [s]	$\log ECF$
167	RXJ1928.0-4050	19:28:04.8	-40:50:04.0	46.2	$0.60 \pm 0.17$	$0.00 \pm 0.22$	31.1$~\pm~$ 6.5	322.3	-10.94
168	RXJ1928.2-3352	19:28:13.1	-33:52:16.1	11.9	$\ge 0.45$	$0.03 \pm 0.45$	8.2$~\pm~$ 3.5	281.6	-10.87
169	RXJ1928.2-3915	19:28:13.3	-39:15:13.5	7.4	$0.76 \pm 0.70$	$\le -0.33$	5.1$~\pm~$ 3.0	320.8	-10.91
170	RXJ1928.3-4031	19:28:20.6	-40:31:19.7	10.3	$\ge 0.48$	$0.85 \pm 0.54$	9.4$~\pm~$ 4.4	325.7	-10.87
171	RXJ1928.5-3508	19:28:31.6	-35:08:02.0	268.9	$0.83 \pm 0.07$	$0.27 \pm 0.11$	88.8$~\pm~$ 9.9	307.2	-10.90
172	RXJ1928.7-3646	19:28:46.3	-36:46:38.6	13.6	$\ge 0.52$	$0.15 \pm 0.35$	9.7$~\pm~$ 3.7	308.9	-10.87
173	RXJ1929.0-3805	19:29:03.2	-38:05:15.8	8.6	$0.39 \pm 0.57$	$\ge 0.42$	7.5$~\pm~$ 4.0	324.6	-10.98
174	RXJ1929.2-4055	19:29:16.0	-40:55:20.4	9.1	$\le -0.43$		5.4$~\pm~$ 2.8	329.9	-11.52
175	RXJ1929.6-4018	19:29:36.5	-40:18:53.6	39.3	$0.80 \pm 0.17$	$0.07 \pm 0.23$	26.9$~\pm~$ 5.9	344.0	-10.90
176	RXJ1929.8-3702	19:29:50.0	-37:02:35.7	14.8	$-0.74 \pm 0.35$	$\ge -0.03$	12.9$~\pm~$ 4.6	318.8	-11.36
177	RXJ1929.9-3338	19:29:57.4	-33:38:16.7	8.9	$\ge 0.38$	$-0.21 \pm 0.43$	8.5$~\pm~$ 3.9	281.0	-10.87
178	RXJ1930.0-3302	19:30:03.1	-33:02:55.2	7.9	$\le -0.57$		6.0$~\pm~$ 3.7	248.9	-11.52
179	RXJ1930.6-3525	19:30:39.2	-35:25:47.5	13.8	$\ge 0.61$	$-0.19 \pm 0.31$	13.6$~\pm~$ 4.7	324.4	-10.87
180	RXJ1931.1-3441	19:31:08.1	-34:41:06.6	11.0	$\ge 0.39$	$\le -0.47$	9.6$~\pm~$ 4.1	319.5	-10.87
181	RXJ1931.4-4008	19:31:25.1	-40:08:46.9	8.8	$0.65 \pm 0.39$	$0.72 \pm 0.38$	6.4$~\pm~$ 3.2	344.1	-10.93
182	RXJ1931.5-3340	19:31:32.5	-33:40:15.9	7.8	$\le -0.51$		5.8$~\pm~$ 3.3	272.9	-11.52
183	RXJ1931.6-3354	19:31:37.7	-33:54:38.7	96.7	$0.93 \pm 0.07$	$0.76 \pm 0.10$	52.5$~\pm~$ 8.4	285.2	-10.88
184	RXJ1932.3-3804	19:32:19.3	-38:04:58.6	7.4	$\ge 0.41$	$0.67 \pm 0.32$	6.0$~\pm~$ 3.3	324.9	-10.87
185	RXJ1932.5-3506	19:32:33.5	-35:06:32.9	7.8	$\ge 0.47$	$-0.46 \pm 0.40$	8.0$~\pm~$ 3.8	313.0	-10.87
186	RXJ1932.5-3837	19:32:34.1	-38:37:00.5	10.6	$\ge 0.22$	$\le -0.54$	6.5$~\pm~$ 3.6	329.6	-10.87
187	RXJ1932.7-3432	19:32:44.3	-34:32:22.7	11.8	$-0.34 \pm 0.31$	$0.50 \pm 0.63$	13.4$~\pm~$ 4.6	305.7	-11.19
188	RXJ1932.7-3858	19:32:45.6	-38:58:39.6	9.5	$0.88 \pm 0.54$	$\le -0.45$	7.4$~\pm~$ 3.6	336.0	-10.89
189	RXJ1932.9-3554	19:32:56.0	-35:54:23.0	7.9	$\ge 0.30$	$\le -0.13$	5.6$~\pm~$ 3.2	314.9	-10.87
190	RXJ1933.2-3337	19:33:18.1	-33:37:29.4	10.5	$0.55 \pm 0.50$	$\ge 0.26$	8.8$~\pm~$ 3.9	284.4	-10.95
191	RXJ1933.3-3812	19:33:20.2	-38:12:30.8	14.7	$0.68 \pm 0.40$	$-0.08 \pm 0.39$	10.9$~\pm~$ 4.0	350.1	-10.92
192	RXJ1933.5-3743	19:33:33.5	-37:43:46.7	7.4	$\le -0.58$		5.6$~\pm~$ 3.5	336.1	-11.52
193	RXJ1933.6-3453	19:33:41.6	-34:53:27.1	11.8	$0.77 \pm 0.34$	$0.48 \pm 0.37$	13.2$~\pm~$ 4.7	321.7	-10.91
194	RXJ1933.8-3522	19:33:51.3	-35:22:53.1	7.6	$-0.29 \pm 0.47$	$\le -0.03$	9.0$~\pm~$ 3.9	320.6	-11.17
195	RXJ1934.5-3620	19:34:33.6	-36:20:43.0	9.0	$\ge 0.51$	$0.06 \pm 0.42$	6.8$~\pm~$ 3.7	318.2	-10.87
196	RXJ1934.6-3433	19:34:41.1	-34:33:33.2	7.7	$\le -0.40$		9.0$~\pm~$ 4.2	328.1	-11.52
197	RXJ1934.7-3805	19:34:46.7	-38:05:06.0	52.9	$0.76 \pm 0.18$	$0.26 \pm 0.20$	30.8$~\pm~$ 6.3	342.6	-10.91
198	RXJ1935.5-3536	19:35:34.2	-35:36:10.9	9.9	$0.42 \pm 0.47$	$0.87 \pm 0.57$	8.3$~\pm~$ 3.5	329.8	-10.98
199	RXJ1936.0-3325	19:36:03.6	-33:25:59.1	8.8	$0.89 \pm 0.38$	$\ge 0.16$	4.5 $~\pm~$2.7	274.4	-10.88
200	RXJ1936.0-4002	19:36:05.6	-40:02:24.6	10.7	$-0.21 \pm 0.39$	$\ge 0.24$	9.9$~\pm~$ 3.8	335.3	-11.14
201	RXJ1936.9-3429	19:36:56.9	-34:29:28.0	9.4	$0.28 \pm 0.42$	$\le -0.44$	8.7$~\pm~$ 3.8	305.6	-11.01
202	RXJ1937.2-3958	19:37:12.6	-39:58:01.1	22.1	$0.41 \pm 0.26$	$0.21 \pm 0.29$	21.6$~\pm~$ 5.6	333.6	-10.98
203	RXJ1937.2-4010	19:37:13.2	-40:10:21.5	11.8	$\ge 0.46$	$0.08 \pm 0.44$	8.8$~\pm~$ 4.0	335.8	-10.87
204	RXJ1938.0-3801	19:38:03.0	-38:01:05.8	10.3	$0.04 \pm 0.49$	$\ge 0.46$	7.7$~\pm~$ 3.6	346.1	-11.07
205	RXJ1938.1-3914	19:38:09.4	-39:14:02.4	9.3	$\ge 0.36$	$\ge 0.42$	3.6$~\pm~$ 2.6	345.0	-10.87
206	RXJ1938.2-4006	19:38:13.1	-40:06:38.1	7.8	$0.55 \pm 0.40$	$\ge 0.50$	7.6$~\pm~$4.0	333.7	-10.95

The moderate energy resolution of the PSPC allows to extract some spectral information from the RASS data, namely so-called hardness ratios, i.e., X-ray colors, which are defined as follows: If Z_s,h1,h2 are the count rates in the bands soft, hard 1, and hard 2, respectively, then

$$% HR~1~=~\frac{ Z_{h1} + Z_{h2} - Z_{s} } { Z_{h1} + Z_{h2} +... ... \quad HR~2~=~\frac{ Z_{h2} - Z_{h1} } { Z_{h2} + Z_{h1}}\cdot$$ (1)

I.e., hardness ratios range from -1 to +1, hardness ratio errors can be larger than 2. If no counts are detected, e.g, in the soft band, then HR 1 = 1, but one can estimate a lower limit to HR 1 by using the upper limit to the soft band count rate $Z_{\rm s}$ in Eq. (1), similar for upper limits to HR 1 as well as for upper and lower limits to HR 2.

In Table 2, we list all RASS X-ray sources detected in our study area with X-ray position, likelihood for existence, hardness ratio, number of counts, exposure time, and individual energy conversion factor

$$% ECF = \left( 5.30 \cdot HR~1 + 8.31 \right) \cdot 10 ^{-12}~{\rm erg~cm} ^{-2}~{\rm cts}^{-1}$$ (2)

according to Schmitt et al. (1995).

In Table 3, we list the optical counterparts to the X-ray sources, most of which are the closest counterparts, but in four cases, the most likely counterpart turned out to be not the closest potential optical counterpart. Table 3 gives optical positions, offsets between X-ray and optical positions, V magnitudes, X-ray to optical flux ratios, identification information, e.g. whether it is a new young star, and remarks, e.g. on previously known stars found among our X-ray sources. The typical positional error of RASS sources is 40 arcsec (Neuhäuser et al. 1995), which we allow as offset between optical and X-ray position for source identification. We searched for stellar counterparts in Simbad, the Hubble Space Telescope Guide Star Catalog (GSC), and the NASA Extragalactic Database (NED). We list in Table 3 the optical positions, V magnitude, X-ray to optical flux ratio, as well as some more information on the identified counterparts. See Sect. 3 for details on the identification. For calculating the X-ray to optical flux ratio, we use

$$% f_{V} = 10 ^{ -0.4 \cdot (V + 13.42) }~{\rm erg~cm} ^{-2}~{\rm s} ^{-1}$$ (3)

(with V in ${\rm mag}$) and the X-ray flux, which we get from the data in Table 2 via

$$% f_{\rm X} = ECF \cdot {\rm counts}/{\rm exposure}.$$ (4)

For sources where we can list only an upper or lower limit to HR 1 (in Table 2), we use HR 1 = 1 or HR 1 = -1, respectively, for calculating the flux according to Eq. (2). The X-ray to optical flux ratio already gives some hints on the nature of an unidentified X-ray source: Extragalactic X-ray sources are optically faint but X-ray bright with $\log (f_{\rm X}/f_{V})~\ge~-0.5$, while normal stars usually have $\log (f_{\rm X}/f_{V})~\le~-1$ (Stocke et al. 1983; Motch et al. 1998).