MUSE-based emission-line maps of the spiral galaxy NGC 4030 reveal the existence of unresolved sources with forbidden line emission enhanced with respect to those seen in its own H ii regions. This study reports our efforts to detect and isolate these objects and identify their nature. Candidates are first detected as unresolved sources on an image of the second principal component of the H β, [O iii] 5007, H α, [N ii] 6584, [S ii] 6716, 6731 emission-line data cube, where they stand out clearly against both the dominant H ii region population and the widespread diffuse emission. The intrinsic emission is then extracted accounting for the highly inhomogeneous emission-line ‘background’ throughout the field of view. Collisional to recombination line ratios like [S ii]/H α, [N ii]/H α, and [O i]/H α tend to increase when the background emission is corrected for. We find that many (but not all) sources detected with the principal component analysis have properties compatible with supernova remnants (SNRs). Applying a combined [S ii]/H α and [N ii]/H α classification criterion leads to a list of 59 sources with SNR-like emission lines. Many of them exhibit conspicuous spectral signatures of SNRs around 7300 Å, and a stacking analysis shows that these features are also present, except weaker, in other cases. At nearly 30 Mpc, these are the most distant SNRs detected by optical means to date. We further report the serendipitous discovery of a luminous (MV ∼ −12.5), blue, and variable source, possibly associated with a supernova impostor.

We have used integral field spectroscopy to study the internal kinematics of the H ii galaxies CTS 1020 and UM 461. We based our analysis on the velocity and velocity dispersion maps, and intensity-velocity dispersion (I − σ) and velocity-velocity dispersion (V r − σ) diagrams. We found that the motion in both star-forming knots of UM 461 has different patterns, suggesting a weak kinematical connection between the knots. The overall kinematics of the galaxy is probably affected by stellar feedback. CTS 1020 has an ordered motion with a gradient compatible with a disc rotating at ∼ 50 km s −1 , though the velocity field is disturbed. In both galaxies the highest and lowest σ values are distributed in the outer parts and are associated with the diffuse gas that permeates the galaxies. UM 461 has a ring-like structure with small regions of increasing σ in the eastern knot, which resemble what we could expect in a collect and collapse scenario of star formation. We found that UM 461 seems to be more susceptible to stellar feedback, whereas in CTS 1020 the gravitational potential dominates.

We present the Deep IFS View of Nuclei of Galaxies (DIVING3D) survey, a seeing-limited optical 3D spectroscopy study of the central regions of all 170 galaxies in the Southern hemisphere with B < 12.0 and |b| > 15○. Most of the observations were taken with the Integral Field Unit of the Gemini Multi-Object Spectrograph, at the Gemini South telescope, but some are also being taken with the SOAR Integral Field Spectrograph. The DIVING3Dsurvey was designed for the study of nuclear emission line properties, circumnuclear (within scales of hundreds of pc) emission-line properties, stellar and gas kinematics and stellar archaeology. The data have a combination of high spatial and spectral resolution not matched by previous surveys and will result in significant contributions for studies related to, for example, the statistics of low-luminosity active galactic nuclei, the ionisation mechanisms in low ionisation nuclear emission-line regions, the nature of transition objects, among other topics.