Search Publications
Physical properties of fullerene-containing Galactic planetary nebulae
Otsuka, Masaaki; Peeters, E.; Bernard-Salas, J. +2 more
We searched the Spitzer Space Telescope data archive for Galactic planetary nebulae (PNe), which show the characteristic 17.4 and 18.9 µm features due to C60, also known as buckminsterfullerene. Out of 338 objects with Spitzer/Infrared Spectrograph data, we found eleven C60-containing PNe, six of which (Hen2-68, IC2501,…
Abundance stratification in Type Ia supernovae - IV. The luminous, peculiar SN 1991T
Pian, E.; Cappellaro, E.; Benetti, S. +4 more
The abundance distribution of the elements in the ejecta of the peculiar, luminous Type Ia supernova (SN Ia) 1991T is obtained modelling spectra from before maximum light until a year after the explosion, with the method of `Abundance Tomography'. SN 1991T is different from other slowly declining SNe Ia (e.g. SN 1999ee) in having a weaker Si II 63…
Outflows from active galactic nuclei: the BLR-NLR metallicity correlation
Valls-Gabaud, David; Du, Pu; Hu, Chen +4 more
The metallicity of active galactic nuclei (AGNs), which can be measured by emission line ratios in their broad- and narrow-line regions (BLRs and NLRs), provides invaluable information about the physical connection between the different components of AGNs. From the archival data bases of the International Ultraviolet Explorer, the Hubble Space Tel…
Broad absorption line variability in radio-loud quasars
Brandt, W. N.; Welling, C. A.; Miller, B. P. +2 more
We investigate C IV broad absorption line (BAL) variability within a sample of 46 radio-loud quasars (RLQs), selected from Sloan Digital Sky Survey (SDSS)/Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) data to include both core-dominated (39) and lobe-dominated (7) objects. The sample consists primarily of high-ionization BAL quasars,…
UV spectral analysis of very hot H-deficient [WCE]-type central stars of planetary nebulae: NGC 2867, NGC 5189, NGC 6905, Pb 6 and Sand 3
Bianchi, Luciana; Keller, Graziela R.; Maciel, Walter J.
We analysed ultraviolet Far Ultraviolet Spectroscopic Explorer, International Ultraviolet Explorer, and Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra of five of the hottest [WCE]-type central stars of planetary nebulae: NGC 2867, NGC 5189, NGC 6905, Pb 6, and Sand 3. The analysis leveraged on our grid of cmfgen synthetic spec…
Rummaging inside the Eskimo's parka: variable asymmetric planetary nebula fast wind and a binary nucleus?
Prinja, R. K.; Urbaneja, M. A.
We report on high-resolution optical time series spectroscopy of the central star of the `Eskimo' planetary nebula NGC 2392. Data sets were secured with the European Southern Observatory (ESO) 2.3 m in 2006 March and Canada-France-Hawaii Telescope (CFHT) 3.6 m in 2010 March to diagnose the fast wind and photospheric properties of the central star.…
Hubble Space Telescope imaging and spectroscopy of the sirius-like triple star system HD 217411
Bond, Howard E.; Barstow, M. A.; Holberg, J. B. +2 more
We present Hubble Space Telescope imaging and spectroscopy of HD 217411, a G3 V star associated with the extreme ultraviolet (UV) excess source (EUV 2RE J2300-07.0). This star is revealed to be a triple system with a G 3V primary (HD 217411 A) separated by ∼1.1 arcsec from a secondary that is in turn composed of an unresolved K0 V star (HD 21741…
Lyman edges in supermassive black hole binaries.
Generozov, A.; Haiman, Z.
We propose a new spectral signature for supermassive black hole binaries (SMBHBs) with circumbinary gas discs: a sharp drop in flux bluewards of the Lyman limit. A prominent edge is produced if the gas dominating the emission in the Lyman continuum region of the spectrum is sufficiently cold (T ≲ 20 000 K) to contain significant neutral hydrogen. …
Ultraviolet characteristics, outflow properties and variability of active galactic nucleus Markarian 1513
Arav, Nahum; Borguet, Benoit; Edmonds, Doug +4 more
We analysed data from the Cosmic Origins Spectrograph (COS) to characterize the spectral properties and outflows of the active galactic nucleus (AGN), Markarian 1513. Further investigation using previous data collected by the Space Telescope Imaging Spectrograph (STIS), Goddard High Resolution Spectrograph (GHRS), and International Ultraviolet Exp…