Related papers: WR bubbles and HeII emission

Aims: Following our comprehensive studies of the WR stars in the Milky Way, we now present spectroscopic analyses of almost all known WN stars in the LMC. Methods: For the quantitative analysis of the wind-dominated emission-line spectra,…

We present new high spectral resolution VLT/UVES spectroscopy and archival HST/STIS imaging and spectroscopy of the giant HII region Tol89 in NGC5398. From optical and UV HST images, we find that the star-forming complex as a whole contains…

We present mid-infrared Spitzer-IRS spectroscopy of the prototype WN star EZ CMa (HD50896, WN4b). Numerous stellar wind lines of HeII are revealed, plus fine-structure lines of [NeIII] 15.5um and [OIV] 25.9um. We carry out a spectroscopic…

We present the analysis of the planetary nebula (PN) NGC 2371 around the [Wolf-Rayet] ([WR]) star WD 0722$+$295. Our Isaac Newton Telescope (INT) Intermediate Dispersion Spectrograph (IDS) spectra, in conjunction with archival optical and…

As part of the VLT/X-shooter science verification, we obtained the first optical medium-resolution spectrum of a previously identified bright O-type object in NGC55, an LMC-like galaxy at a distance of \sim2.0 Mpc. Based on the stellar and…

We present a study of the ionized, neutral atomic, and molecular gas associated with the ring nebula RCW 78 around the WR star HD 117688 (= WR 55). We based our study on CO observations carried out with the SEST and NANTEN telescopes. We…

We provide line luminosities and spectroscopic templates of prominent optical emission lines of 133 Galactic Wolf-Rayet stars by exploiting Gaia DR3 parallaxes and optical spectrophotometry, and provide comparisons with 112 counterparts in…

The Wolf-Rayet (WR) bubble S 308 around the WR star HD 50896 is one of the only two WR bubbles known to possess X-ray emission. We present XMM-Newton observations of three fields of this WR bubble that, in conjunction with an existing…

We have discovered a ~45 kpc Lya nebula (or Lya ``blob'') at z~1.67 which exhibits strong, spatially-extended HeII emission and very weak CIV and CIII] emission. This is the first spatially-extended Lya+HeII emitter observed and the lowest…

We present images and slitless spectra which were obtained in HST surveys of Planetary Nebulae (PNe) in both the Large and Small Magellanic Clouds, using the Space Telescope Imaging Spectrograph. These new data on 59 PNe (54 in the LMC and…

We performed a detailed photometric analysis and photoionisation modelling on three high excitation multiple shell planetary nebulae: NGC 3242, NGC 6826 and NGC 7662. Archival HST/WFPC2 narrow band filter images were used to investigate…

We report the discovery of a relatively faint (V=15.5) early-type WN star in the SMC. The line strength and width of He II lambda 4686 emission is similar to that of the other SMC WNs, and the presense of N V lambda 4603,19 emission…

The origin of nebular HeII emission, which is frequently observed in low-metallicity (O/H) star-forming galaxies, remains largely an unsolved question. Using the observed anticorrelation of the integrated X-ray luminosity per unit of star…

We obtained new optical spectra of 13 H II regions in WLM with EFOSC2; oxygen abundances are derived for nine H II regions. The temperature-sensitive [O III] 4363 emission line was measured in two bright H II regions HM7 and HM9. The direct…

We present the results of deep optical spectroscopic observations using the LRIS spectrograph on the Keck I 10-m telescope of three ultra-luminous X-ray sources (ULXs), Ho IX X-1; M81 X-6; and Ho II X-1. Our observations reveal the…

We present the results of Chandra X-ray Observatory (CXO) observations of the planetary nebulae (PNs) NGC 40 and Hen 2-99. Both PNs feature late-type Wolf-Rayet central stars that are presently driving fast ~1000 km/s, massive winds into…

We present a study of the diffuse X-ray emission from the star forming region LMC-N 57 in the Large Magellanic Cloud (LMC). We use archival XMM-Newton observations to unveil in detail the distribution of hot bubbles in this complex. X-ray…

We present long-slit observations in the optical and near infrared of eight HII regions in the spiral galaxy NGC 4258. Six of the observed regions are located in the SE inner spiral arms and the other two are isolated in the northern outer…

[13CII] observations in several Galactic sources show that the fine-structure [12CII] emission is often optically thick (the optical depths around 1 to a few). The aim of our study is to test whether this also affects the [12CII] emission…

As part of a search for Wolf-Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He ii and Balmer absorption lines…