The radio-continuum emission of the LMC has been investigated numerous times at several frequencies. The first catalogue of radio sources in the LMC (MC catalogue) was obtained by McGee et al. (1972a,b). They observed the LMC with the Parkes radio telescope at 5 GHz and 2.7 GHz. As a part of the whole sky survey at 0.408 GHz the LMC has been observed by Clark et al. (1976) using the Molonglo radio telescope. They detected 227 sources presented in the MC4 catalogue. Recent surveys of the LMC include the observations with Parkes at several frequencies (1.4 GHz, 2.45 GHz, 4.75 GHz and 8.55 GHz) (Filipovic et al. 1995) revealing 469 discrete sources, the PMN southern sky survey at 4.85 GHz (Wright et al. 1994) and the MOST survey at 0.843 GHz (Mills et al. 1984a,b; Ye et al., in preparation).
The Australia Telescope Compact Array (ATCA) offers the possibility of surveying compact sources in and behind the LMC with much higher spatial resolution than has been possible previously. Here we present the results of a short (12 min per field) ATCA continuum survey ("snapshot'' survey) at 1.4 GHz and 2.4 GHz in the region of the giant molecular cloud and 30 Doradus.
This catalogue of compact (subarcminute) sources is useful for several
purposes.
Compact sources are needed to search for neutral-hydrogen 21 cm-line
absorption. To study the cool (
) atomic gas in the LMC
an interferometer is necessary, because it acts as a spatial
filter, removing the extended emission which confuses the absorption
measurement. Baselines longer than about
800 m (3000 wavelengths) are needed (Dickey et al. 1994;
Marx et al. in preparation), so the
background sources must be smaller than about 50''.
The deepest survey of the LMC with sufficiently high angular resolution,
the MOST
survey (0.75'), is not sensitive enough to include all sources
which are useful for an HI-absorption study of the LMC.
A list of point sources complete to about 6 mJy peak flux density at 1.4 GHz
and to about 3 mJy at 2.4 GHz is
given by the present ATCA snapshot survey.
The compact radio sources in directions towards the LMC are also interesting in themselves. Most compact radio sources are background objects like quasars or Seyfert galaxies. But there are also compact objects located within the LMC. These intrinsic sources are of peculiar interest, as they might be compact HII regions (Habing & Israel 1979), young supernova remnants or planetary nebulae. A list of compact radio sources is the first step toward identifying such objects.