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The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of He II λ1640 in young star clusters
Howarth, I. D.; Angus, C. R.; Lennon, D. J. +17 more
We introduce a Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph (STIS) stellar census of R136a, the central ionizing star cluster of 30 Doradus. We present low resolution far-ultraviolet STIS spectroscopy of R136 using 17 contiguous 52 arcsec × 0.2 arcsec slits which together provide complete coverage of the central 0.85 parsec (3…
The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and its implications for the trigger for relativistic jets
Done, Chris; Jin, Chichuan
Relativistic reflection models of the X-ray spectrum of the `complex' Narrow Line Seyfert 1 (NLS1) 1H 0707-495 require a high-spin, moderate-inclination, low-mass black hole. With these parameters fixed, the observed optical/UV emission directly determines the mass accretion rate through the outer disc and hence predicts the bolometric luminosity.…
SU Lyncis, a hard X-ray bright M giant: clues point to a large hidden population of symbiotic stars
Nuñez, N. E.; Nelson, T.; Mukai, K. +6 more
Symbiotic star surveys have traditionally relied almost exclusively on low resolution optical spectroscopy. However, we can obtain a more reliable estimate of their total Galactic population by using all available signatures of the symbiotic phenomenon. Here we report the discovery of a hard X-ray source, 4PBC J0642.9+5528, in the Swift hard X-ray…
Abundance stratification in Type Ia supernovae - V. SN 1986G bridging the gap between normal and subluminous SNe Ia
Pian, E.; Ashall, C.; Mazzali, P. A. +1 more
A detailed spectroscopic analysis of SN 1986G has been performed. SN 1986G `bridges the gap' between normal and subluminous Type Ia supernovae (SNe Ia). The abundance tomography technique is used to determine the abundance distribution of the elements in the ejecta. SN 1986G was found to be a low-energy Chandrasekhar mass explosion. Its kinetic en…
X-ray, UV and optical analysis of supergiants: ɛ Ori
Hillier, D. John; Leutenegger, Maurice A.; Cohen, David H. +2 more
We present a multi-wavelength (X-ray to optical) analysis, based on non-local thermodynamic equilibrium photospheric+wind models, of the B0 Ia-supergiant: ɛ Ori. The aim is to test the consistency of physical parameters, such as the mass-loss rate and CNO abundances, derived from different spectral bands. The derived mass-loss rate is {dot {M}} / …
Spectroscopic study of the HgMn star HD 49606: the quest for binarity, abundance stratifications and magnetic field
Giarrusso, M.; Leone, F.; Scalia, C. +4 more
In this paper, we present a multi-instrument analysis of the mercury-manganese star HD 49606. New spectroscopic observations have been obtained by us with Catania Astrophysical Observatory Spectropolarimeter (CAOS@OAC) and High Accuracy Radial Velocity Planet Searcher-North@Telescopio Nazionale Galileo (HARPS-N@TNG). Combining these observations w…
The CHARA Array resolves the long-period Wolf-Rayet binaries WR 137 and WR 138
Gies, Douglas R.; Moffat, Anthony F. J.; Richardson, Noel D. +10 more
We report on interferometric observations with the CHARA Array of two classical Wolf-Rayet (WR) stars in suspected binary systems, namely WR 137 and WR 138. In both cases, we resolve the component stars to be separated by a few milliarcseconds. The data were collected in the H band, and provide a measure of the fractional flux for both stars in ea…
Bright stars observed by FIMS/SPEAR
Edelstein, Jerry; Jo, Young-Soo; Choi, Yeon-Ju +5 more
In this paper, we present a catalogue of the spectra of bright stars observed during the sky survey using the Far-Ultraviolet Imaging Spectrograph (FIMS), which was designed primarily to observe diffuse emissions. By carefully eliminating the contamination from the diffuse background, we obtain the spectra of 70 bright stars observed for the first…
Observations of the planetary nebula RWT 152 with OSIRIS/GTC
Solano, E.; Ulla, A.; Miranda, L. F. +2 more
RWT 152 is one of the few known planetary nebulae with an sdO central star. We present subarcsecond red tunable filter Hα imaging and intermediate-resolution, long-slit spectroscopy of RWT 152 obtained with OSIRIS/GTC (Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy/Gran Telescopio Canarias) with the goal of anal…