We present large scale 870 \mu m maps of the nearby starburst galaxies NGC 253 and NGC 4945 as well as the nearest giant elliptical radio galaxy Centaurus A ( NGC 5128 ) obtained with the newly commissioned Large Apex Bolometer Camera ( LABOCA ) operated at the Atacama Pathfinder Experiment telescope .
Our continuum images reveal for the first time the distribution of cold dust at a angular resolution of 20 ^ { \prime \prime } across the entire optical disks of NGC 253 and NGC 4945 out to a radial distance of 10 ^ { \prime } ( 7.5 kpc ) .
In NGC 5128 our LABOCA image also shows , for the first time at submillimeter wavelengths , the synchrotron emission associated with the radio jet and the inner radio lobes .
From an analysis of the 870 \mu m emission in conjunction with ISO-LWS , IRAS and long wavelengths radio data we find temperatures for the cold dust in the disks of all three galaxies of 17–20 K , comparable to the dust temperatures in the disk of the Milky Way .
The total gas mass in the three galaxies is determined to be 2.1 , 4.2 and 2.8 \times 10 ^ { 9 } { { M } _ { \odot } } for NGC 253 , NGC 4945 and NGC 5128 , respectively .
The mass of the warmer ( 30–40 K ) gas associated with the central starburst regions in NGC 253 and NGC 4945 only accounts for \sim 10 \% of the total gas mass .
A detailed comparison between the gas masses derived from the dust continuum and the integrated CO ( 1–0 ) intensity in NGC 253 suggests that changes of the CO luminosity to molecular mass conversion factor are mainly driven by a metallicity gradient and only to a lesser degree by variations of the CO excitation .
An analysis of the synchrotron spectrum in the northern radio lobe of NGC 5128 shows that the synchrotron emission from radio to the ultraviolet ( UV ) wavelengths is well described by a broken power law and that the break frequency is a function of the distance from the radio core as expected for aging electrons .
We derive an outflow speed of \sim 0.5 c at a distance of 2.6 kpc from the center , consistent with the speed derived in the vicinity of the nucleus .