We analyze spectral properties of 1671 galaxies from the Stromlo-APM survey, selected to have 15 ≤ bJ ≤ 17.15 and having a mean redshift z = 0.05. This is a representative local sample of field galaxies, so the global properties of the galaxy population provide a comparative point for analysis of more distant surveys. We measure Hα, [O II] λ3727, [S II] λλ6716, 6731, [N II] λ6583 and [O I] λ630...

A correlation between the orbital period and the strength of the Hα line in Be/X-ray binaries has been found. Those systems with shorter orbital periods show less emission in Hα than those with longer orbital periods. The neutron star appears to act as a barrier which prevents the formation of a extended disk in systems with short orbital period.

We present and analyze the correlations between mid-infrared (MIR), farinfrared (FIR), total-infrared (TIR), Hα, and FUV luminosities for star-forming galaxies, composite galaxies and AGNs, based on a large sample of galaxies selected from the Spitzer SWIRE fields. The MIR luminosities of star-forming galaxies are well correlated with their Hα, TIR and FUV luminosities, and we re-scaled the MIR...

We present wide-field Hα images of the Galactic supernova remnant G156.2+5.7 which reveal the presence of considerable faint Hα line emission coincident with the remnant’s X-ray emission. We also present low-resolution optical spectra for a few representative emission regions. The outermost Hα emission consists largely of long and thin (unresolved), smoothly curved filaments of Balmer-dominated...

We present Hα spectropolarimetry observations of a sample of 23 Herbig Ae/Be stars. A change in the linear polarisation across Hα is detected in a large fraction of the objects, which indicates that the regions around Herbig stars are flattened (disclike) on small scales. A second outcome of our study is that the spectropolarimetric signatures for the Ae stars differ from those of the Herbig Be...

We report a new Fabry-Perot search for Hα emission from the intergalactic cloud HI 1225+01 in an attempt to measure the low redshift ionizing background radiation. We set a new 2σ upper limit on Hα emission of 8 mR (5 × 10 ergs cm s arcsec). Conversion of this limit to limits on the strength of

It is now apparent that classical T Tauri-like outflows commonly accompany the formation of young brown dwarfs. To date two optical outflows have been discovered and results presented in this paper increase this number to three. Using spectro-astrometry the origin of the LS-RCrA 1 forbidden emission lines in a blue-shifted outflow is confirmed. The non-detection of the red-shifted component of ...

Long-slit observations of the blue compact galaxy Haro 2 have been performed around Hα and Hβ. The main aim of these observations was to detect the Hα emission originating in the partially ionized wind outflowing at 200 km/s, that had been previously detected with the Hubble Space Telescope (HST). A shallow broadening of the Hα line wings has been observed, consistent with the existence of an e...

We investigate the far-infrared (far-IR) properties of galaxies selected via deep, narrow-band imaging of the Hα emission line in four redshift slices from z = 0.40–2.23 over ∼ 1 deg as part of the Highredshift Emission Line Survey (HiZELS). We use a stacking approach in the Herschel PACS/SPIRE far-IR bands, along with 850μm imaging from SCUBA-2 and Very Large Array (VLA) 1.4GHz imaging to stud...

We study the two main corrections generally applied to narrow-band Hα fluxes from galaxies in order to convert them to star formation rates, namely for [N] contamination and for extinction internal to the galaxy. From an imaging study using carefully chosen narrow-band filters, we find the [N] and Hα emission to be differently distributed. Nuclear measurements are likely to overestimate the...