1 Introduction

Low surface brightness (LSB) dwarf galaxies are believed to be the most numerous galaxy population in the Universe. They are recognized as ideal laboratories to study star formation in different types of galaxies, the evolution of the interstellar medium, and the amount and nature of galactic dark matter; they also represent a key element in studies of galaxy formation and evolution in general. LSB dwarf galaxies are difficult to detect because their surface brightness is typically only a few percent above the dark night sky. For this reason their total number remains unknown even within the Local Group boundaries, not to mention the Local Supercluster and beyond. Some authors believe that $\sim$90% of all galaxies have surface brightness below the currently achieved detection limit (Disney & Phillips 1983; McGaugh 1996).

Systematic all-sky searches for LSB dwarfs began after the public distribution of the first photographic survey of the Northern sky (= POSS-I), which covers a sky area at declinations $D > -30\hbox{$^\circ$ }$(van den Bergh 1959, 1966; Karachentseva 1968, 1972, 1973). Also many dwarf galaxies were found when general galaxy catalogues, such as MCG (Vorontsov-Velyaminov et al. 1962), UGC (Nilson 1973), UGCA (Nilson 1974) were compiled based on the POSS-I.

A special search for LSB dwarfs in the southern sky has been conducted by Feitzinger & Galinsky (1985) on the ESO/SERC sky survey covering a sky area below $-18\hbox{$^\circ$ }$. A large number of LSB dwarfs entered in the catalogues by Lauberts (1982) and Arp & Madore (1987) are based on that survey. Note that due to the better quality of photographic material used for the ESO/SERC survey, one may detect objects that are fainter and have lower surface brightness than those achievable with the POSS-I.

Different lists of LSB dwarf galaxies compiled before 1987 were reinspected by Karachentseva & Sharina (1988). After re-inspection of several thousand objects presented in different catalogues and lists, they compiled a catalogue of about 1500 LSB dwarf galaxies. The catalogue covers all the sky and has a characteristic depth of $\sim 20$ Mpc matching the Local Supercluster boundaries.

 

Table 1: List of new dwarf galaxy candidates found in the SERC EJ zone

No	RA (1950.0) Dec.	$a\times b$		Type	SB	NED ident.	Notes
1	2	3		4	5	6	7
1	$00^{\rm h}23^{\rm m}38\hbox{$.\!\!^{\rm s}$ }5 -11\hbox{$^\circ$ }19\hbox{$^\prime$ }50\hbox{$^{\prime\prime}$ }$	$5\hbox{$.\mkern-4mu^\prime$ }0$	$4\hbox{$.\mkern-4mu^\prime$ }3$	Sph	VL	Cetus	LG member [1]
2	00 37 44.6 - 18 06 04	0.9	0.6	Sph/Ir	L	Scu 26	granulated
3	01 32 16.7 - 07 36 38	0.6	0.4	Ir	L	kdg 7	N615 5' NE [2]
4	02 39 19.2 - 08 36 54	1.2	1.1	Sph	L		in N1052 gr.?
5	02 47 03.0 - 13 25 06	1.0	0.5	Ir	L
6	04 27 59.2 - 14 18 56	0.9	0.4	Ir	L
7	05 57 02.8 - 13 05 28	0.8	0.2	Ir	L		distant?
8	06 42 15.2 - 17 52 51	1.8	0.3	Ir	H	IC 2171	different $V_{\rm h}$[3]
9	06 44 44.3 - 17 53 10	0.5	0.35	Epec	H	CGMW 1-0381	$V_{\rm h}$ = 696
10	07 10 28.9 - 07 44 12	1.0	0.25	Ir	L
11	07 28 41.0 - 00 52 04	0.7	0.4	Ir	L		distant?
12	08 51 05.8 - 17 47 42	0.5	0.4	Ir	L		patchy
13	09 33 05.4 - 16 06 34	1.2	0.2	Ir	VL	VC,94	4 gal. $\sim7\hbox{$^\prime$ }$ SW
14	09 37 55.0 - 03 39 30	1.1	1.0	Ir	L	PGC 27612
15	09 52 40.9 - 06 02 00	1.3	0.3	Ir?	H	APMUKS	comp. N3115?
16	09 57 18.2 - 09 06 39	0.9	0.7	Ir?	VL		comp. N3115?
17	09 59 09.4 - 08 00 27	1.4	0.25	Ir	H	MCG-1-26-11	comp. N3115?
18	10 03 12.3 - 07 44 16	1.7	1.4	S0pec	H	NGC 3115dw1	$V_{\rm h}$ = 698
19	10 22 00.5 - 12 10 43	0.7	0.6	Ir	L
20	11 02 06.3 + 00 19 40	0.5	0.4	Ir/Sph	L	APMUKS	comp. N3521?
21	11 03 01.7 - 01 35 36	1.7	0.8	Ir	L	UGC 6145	$V_{\rm h}$ = 740, c. N3521?
22	11 03 34.5 - 01 10 36	0.5	0.4	Ir?	L	APMUKS	comp. N3521?
23	11 03 42.2 - 14 08 04	3.5	1.2	Ir	L
24	11 11 20.3 - 03 15 31	0.5	0.4	Ir	L	APMUKS
25	11 42 45.5 - 16 59 46	1.2	0.7	Ir	VL		v. blue
26	11 51 18.3 - 14 44 51	1.8	1.1	Ir	VL		v. blue
27	12 19 30.9 - 09 31 23	0.8	0.3	Ir	L		distant?
28	12 21 22.0 - 14 40 34	1.2	1.0	Ir	EL
29	12 34 38.4 - 10 13 21	1.4	0.6	Ir	L	PGC 42120	comp. N4594?
30	12 35 00.5 - 08 35 32	1.0	0.5	Ir	L		comp. N4594?
31	12 35 58.0 - 10 12 56	0.8	0.7	Sph	VL		comp. N4594?
32	12 37 18.3 - 11 28 35	0.6	0.5	Sph	EL		comp. N4594?
33	12 37 32.7 - 12 05 25	0.5	0.4	Sph	VL		comp. N4594?
34	12 38 42.7 - 11 39 12	0.8	0.7	Sph	VL		comp. N4594?
35	12 39 58.6 - 14 40 02	0.4	0.4	Ir	EL		bluish
36	12 44 02.8 - 03 48 10	0.9	0.65	Ir	L	kdg 198
37	12 45 24.2 - 12 23 00	0.6	0.5	Sph?	VL
38	12 50 56.6 - 05 39 25	1.2	0.5	Ir	L	APMUKS
39	12 51 06.5 - 05 48 46	0.8	0.6	Sph	EL
40	12 57 15.7 - 13 51 04	1.0	0.6	Ir	VL
41	13 03 07.6 - 07 29 29	1.4	1.1	Ir	L	kdg 218	comp. N4948?
42	13 03 42.7 - 07 49 31	1.2	0.9	Ir	VL		comp. N4948?
43	13 06 39.6 - 17 05 55	0.7	0.5	Ir?	EL
44	13 30 23.5 - 12 00 20	0.5	0.3	Ir	L		blue; distant?
45	14 11 06.0 - 01 57 12	0.6	0.4	Sph?	VL	kdg 230	distant?
46	14 25 47.0 - 08 41 55	0.5	0.5	Ir	L		distant?
47	14 32 38.5 - 16 56 43	1.8	0.9	Ir	L
48	16 03 02.4 - 04 26 16	1.3	1.0	Ir	L		distant S?
49	16 40 45.7 - 07 58 00	1.1	0.4	Ir	L		distant?
50	17 39 00.1 - 04 35 59	1.3	0.5	Ir	L		distant S?

[1] Discovered by Whiting et al. (1999).
[2] Probably belongs to a group of NGC 584, 596, 600, 615 with the mean $V_{\rm h} = 1850$ km s^-1.
[3] There are two different velocity estimates: $V_{\rm h}$ = 3395 km s^-1. $\quad$ (Visvanathan & Yamada 1996), and $V_{\rm h}$ = 784 km s^-1 (Theureau et al. 1998).