Related papers: Rule or exception? Planetary nebulae around hot su…
RWT 152 is one of the few known planetary nebulae with an sdO central star. We present subarcsecond red tunable filter Halpha imaging and intermediate-resolution, long-slit spectroscopy of RWT 152 obtained with OSIRIS/GTC with the goal of…
RWT 152 is one of the few planetary nebula with an sdO central star. We present subarcsecond red tunable filter imaging and intermediate-resolution, long-slit spectroscopy of RWT 152, obtained with OSIRIS/GTC, which allow us to describe in…
We present narrow-band Halpha and [OIII] images, and high-resolution, long-slit spectra of the planetary nebulae (PNe) Abell36, DeHt2, and RWT152 aimed at studying their morphology and internal kinematics. These data are complemented with…
(Abridged) The origin of hot subdwarf O-type stars (sdOs) remains unclear since their discovery in 1947. Among others, a post-Asymptotic Giant Branch (post-AGB) origin is possible for a fraction of sdOs. We are involved in a comprehensive…
Planetary nebulae (PNe) consist of an ionized envelope surrounding a hot central star (CSPN) that emits mostly at ultraviolet (UV) wavelengths. Ultraviolet observations, therefore, provide important information on both the CSPN and the…
Hot subdwarf stars (sdO/Bs) are the stripped cores of red giants located at the bluest extension of the horizontal branch. They constitute the dominant population of UV-bright stars in old stellar environments and are most likely formed by…
We have developed a method to identify planetary nebula (PN) candidates in imaging data of the Sloan Digital Sky Survey (SDSS). This method exploits the SDSS' five-band sampling of emission lines in PN spectra, which results in a color…
We present a possible evolutionary pathway to form planetary nebulae (PNe) with close neutron star (NS)-white dwarf (WD) binary central stars. By employing a comprehensive binary population synthesis technique we find that the evolution…
Planetary nebulae (PNe) are the only single stars in galaxies outside the Local Group that can be used as kinematic tracers of the diffuse light in the extended halo. Analysing their luminosity-specific number density across galaxies of…
We report the results of an [O III] 5007 spectroscopic survey for planetary nebulae (PNe) located within the star clusters of M31. By examining R ~ 5000 spectra taken with the WIYN+Hydra spectrograph, we identify 3 PN candidates in a sample…
Context. There are more than 3000 true and probable known Galactic Planetary Nebulae (PNe), but only for 13% of them there is central star spectroscopic information available. Aims. To contribute to the knowledge of central stars of…
Diffuse X-ray emission has been detected in a small number of planetary nebulae (PNe), indicating the existence of shocked fast stellar winds and providing support for the interacting-stellar-winds formation scenario of PNe. However, the…
The kinematic structure of a sample of planetary nebulae, consisting of 23 [WR] central stars, 21 weak emission line stars (wels) and 57 non-emission line central stars, is studied. The [WR] stars are shown to be surrounded by turbulent…
Spectroscopic observations have been carried out for eleven objects believed to be planetary nebulae on the basis of their optical appearance. They were discovered in an ongoing deep search for galaxies in the Southern Milky Way…
While pulsar wind nebulae (PWNe) and their associated isolated pulsars are commonly detected at X-ray energies, they are much rarer at near infrared (nIR) and optical wavelengths. Here we examine three PWN systems in the Galactic plane -…
We present Gemini-South observations of nine faint and extended planetary nebulae. Using direct images taken with the spectrograph GMOS, we built the $(u' - g')$ vs. $(g' - r')$ diagrams of the stars in the observed areas which allowed us,…
We present deep Halpha+[N II] CCD images of selected new Planetary Nebulae (PNe) discovered through an [O III] 5007 A emission line survey in the Galactic Bulge region with l > 0 deg. In total, we detected more than 200 objects, including…
A number of efforts are underway to detect close binary stars in planetary nebulae. The primary goal of these studies is to determine the binary fraction of central stars. The next stage is a detailed analysis of the binaries to determine…
Context: Planetary nebulae (PNe) are excellent tracers of stellar populations with low surface brightness, and therefore provide a powerful method to detect and explore the rich system of substructures discovered around the main spiral…
In latest years, the high sensitivity of the instruments on-board the XMM-Newton and Chandra satellites allowed us to explore the properties of the X-ray emission from hot subdwarf stars. The small but growing sample of X-ray detected hot…