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Wide-field, very long baseline interferometry (VLBI) observations of the nearby starburst galaxy NGC 253, obtained with the Australian Long Baseline Array (LBA), have produced a 2.3 GHz image with a maximum angular resolution of 15 mas (0.3 pc). Six sources were detected, all corresponding to sources identified in higher frequency (>5 GHz) VLA images. One of the sources, supernova remnant 5.48-43.3, is resolved into a shell-like structure approximately 90 mas (1.7 pc) in diameter. From these data and data from the literature, the spectra of 20 compact radio sources in NGC 253 were modelled and found to be consistent with free-free absorbed power laws. Broadly, the free-free opacity is highest toward the nucleus but varies significantly throughout the nuclear region (tau_0 ~ 1->20), implying that the overall structure of the ionised medium is clumpy. Of the 20 sources, nine have flat intrinsic spectra associated with thermal radio emission and the remaining 11 have steep intrinsic spectra, associated with synchrotron emission from supernova remnants. A supernova rate upper limit of 2.4 yr^-1 is determined for the inner 320 pc region of the galaxy at the 95% confidence level, based on the lack of detection of new sources in observations spanning almost 17 years and a simple model for the evolution of supernova remnants. A supernova rate of >0.14 (v/10^4) yr^-1 is implied from estimates of supernova remnant source counts, sizes and expansion rates, where v is the radial expansion velocity of the supernova remnant in km s^-1. A star formation rate of 3.4 (v/10^4) < SFR(M<=5Msun) < 59 Msun yr^-1 has been estimated directly from the supernova rate limits and is of the same order of magnitude as rates determined from integrated FIR and radio luminosities.
Wide-field VLBI observations of the nearby starburst galaxy NGC 4945, obtained with the Australian LBA, have produced 2.3 GHz images over two epochs with a maximum spatial resolution of 0.3 pc. 15 sources were detected, 13 of which correspond to sour
We searched for X-ray supernova remnants (SNRs) in the starburst region of M82, using archival data from the Chandra X-ray Observatory with a total effective exposure time of 620 ks with an X-ray spectroscopic selection. Strong line-emission from Fe
Observations of the nearby starburst galaxy NGC 253 in the 21-cm line reveal the presence of neutral hydrogen in the halo, up to 12 kpc from the galactic plane. This extra-planar HI is found only in one half of the galaxy and is concentrated in a hal
We present a study of the young population in the starburst galaxy NGC 253. In particular, we focused our attention on searching young star groups, obtaining their main properties and studying their hierarchical organization. For this task, we used m
We present submillimeter spectra of the (proto-)super star cluster (SSC) candidates in the starbursting center of the nearby galaxy NGC 253 identified by Leroy et al. (2018). The 2.5pc resolution of our ALMA cycle 3 observations approach the size of