Groh, Jose H., Damineli, Augusto, Hillier, D. John, Barba, Rodolfo, Fernandez-Lajus, Eduardo, Gamen, Roberto C., ...
We report optical observations of the Luminous Blue Variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to Si...
Groh, Jose H., Hillier, D. John, Damineli, Augusto, Whitelock, Patricia A., Marang, Fred, Rossi, C.
We present a detailed spectroscopic analysis of the luminous blue variable AG Carinae during the last two visual minimum phases of its S-Dor cycle (1985-1990 and 2000-2003). The analysis reveals an...
SN 1994W: an interacting supernova or two interacting shells? (2009)
Dessart, Luc, Hillier, D. John, Gezari, Suvi, Basa, Stéphane, Matheson, Tom
We present a multi-epoch quantitative spectroscopic analysis of the Type IIn supernova (Type IIn SN) 1994W, an event interpreted by Chugai et al. as stemming from the interaction between the ejecta...
Metallicity in the Galactic Center: The Quintuplet cluster (2008)
Najarro, Francisco, Figer, Don F., Hillier, D. John, Geballe, T. R., Kudritzki, Rolf P.
We present a measurement of metallicity in the Galactic center Quintuplet Cluster made using quantitative spectral analysis of two Luminous Blue Variables (LBVs). The analysis employs line-blanketed...
Probing Shock Breakout with Serendipitous GALEX Detections of Two SNLS Type II-P Supernovae (2008)
Gezari, Suvi, Dessart, Luc, Basa, Stéphane, Martin, D. Christopher, Neill, James D., Woosley, S. E., ...
We report the serendipitous detection by GALEX of fast (
Probing Shock Breakout with Serendipitous GALEX Detections of Two SNLS Type II-P Supernovae (2008)
Gezari, Suvi, Dessart, Luc, Basa, Stephane, Martin, D. Chris, Neill, James D., Woosley, S. E., ...
We report the serendipitous detection by GALEX of fast (1 mag) UV emission from two Type II plateau (II-P) supernovae (SNe) at z=0.185 and 0.324 discovered by the Supernova Legacy Survey. Optical...
SN 1994W: An Interacting Supernova or Two Interacting Shells? (2008)
Dessart, Luc, Hillier, D. John, Gezari, Suvi, Basa, Stephane, Matheson, Tom
We present a multi-epoch quantitative spectroscopic analysis of the Type IIn SN 1994W, an event interpreted by Chugai et al. as stemming from the interaction between the ejecta of a SN and a 0.4Msun...
The Neon Abundance in WC stars II. ISO/SWS Spectroscopy of HD 156385 (WR90) (2007)
Luc Dessart, Allan J. Willis, Paul A. Crowther, D. John Hillier
In general, observationally derived wind compositions of WR stars are in reasonable agreement with predictions from stellar evolution models for massive stars. However, Barlow et al. (1988)...
A Massive Star Odyssey, from Main Sequence to Supernova (2007)
Proceedings Iau Symposium, A. Herrero, C. Esteban, Christopher J. Evans, Paul A. Crowther, ...
We present results from optical and ultraviolet analysis of nine LMC/SMC supergiants. Temperatures, mass-loss rates and CNO abundances are obtained using the non-LTE, line-blanketed model atmosphere...
Dessart, Luc, Blondin, Stephane, Brown, Peter J., Hicken, Malcolm, Hillier, D. John, Holland, Stephen T., ...
We analyze the Type II Plateau supernovae (SN II-P) 2005cs and 2006bp with the non-LTE model atmosphere code CMFGEN. We fit 13 spectra in the first month for SN 2005cs and 18 for SN 2006bp. {\sl...
Time-dependent Effects in Photospheric-Phase Type II Supernova Spectra (2007)
Dessart, Luc, Hillier, D. John
Spectroscopic modeling of Type II supernovae (SNe) generally assumes steady-state. Following the recent suggestion of Utrobin & Chugai, but using the 1D non-LTE line-blanketed model atmosphere code...
X-ray Spectral Variation of Eta Carinae through the 2003 X-ray Minimum (2007)
Hamaguchi, Kenji, Corcoran, Michael F., Gull, Theodore, Ishibashi, Kazunori, Pittard, Julian M., Hillier, D. John, ...
We report the results of an X-ray observing campaign on the massive, evolved star Eta Carinae, concentrating on the 2003 X-ray minimum as seen by the XMM-Newton observatory. These are the first...
Time-dependence Effects in Photospheric-Phase Type II Supernova Spectra (2007)
Because of radiative cooling and the fast expansion of the exploding mantle of the progenitor massive star, photospheric-phase Type II SN spectra evolve rapidly. At shock breakout the spectral energy
The UV Scattering Halo of the Central Source Associated with Eta Carinae (2006)
Hillier, D. John, Gull, T., Nielsen, K., Sonneborn, G., Iping, R., Smith, Nathan, ...
We have made an extensive study of the UV spectrum of Eta Carinae, and find that we do not directly observe the star and its wind in the UV. Because of dust along our line of sight, the UV light that...
Detection of a Hot Binary Companion of $\eta$ Carinae (2005)
Iping, Rosina C., Sonneborn, George, Gull, Theodore R., Massa, Derck L., Hillier, D. John
We report the detection of a hot companion of $\eta$ Carinae using high resolution spectra (905 - 1180 \AA) obtained with the Far Ultraviolet Spectroscopic Explorer (\fuse) satellite. Observations...
Quantitative spectroscopic analysis of and distance to SN1999em (2005)
Dessart, Luc, Hillier, D. John
This work presents a detailed quantitative spectroscopic analysis of, and the determination of the distance to, the type II supernovae (SN) SN1999em with CMFGEN (Dessart & Hillier 2005a), based on...
Characteristic QSO Accretion Disk Temperatures from Spectroscopic Continuum Variability (2005)
Pereyra, Nicolas A., Berk, Daniel E. Vanden, Turnshek, David A., Hillier, D. John, Wilhite, Brian C., Kron, Richard G., ...
Using Sloan Digital Sky Survey (SDSS) quasar spectra taken at multiple epochs, we find that the composite flux density differences in the rest frame wavelength range 1300-6000 AA can be fit by a...
On the Steady Nature of Line-Driven Disk Winds: Application to Cataclysmic Variables (2005)
Pereyra, Nicolas A., Turnshek, David A., Hillier, D. John
We apply the semi-analytical analysis of the steady nature of line-driven winds presented in two earlier papers to disk winds driven by the flux distribution of a standard Shakura & Sunyaev (1973)...
Distance determinations using type II supernovae and the expanding photosphere method (2005)
Dessart, Luc, Hillier, D. John
Due to their high intrinsic brightness, type II supernovae (SN) can be used as lighthouses to constrain distances in the Universe using variants of the Baade-Wesselink method. Based on a large set of...
Metallicity in the Galactic Center: The Arches cluster (2004)
Najarro, Francisco, Figer, Donald F., Hillier, D. John, Kudritzki, Rolf P.
We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most...
Kinematics and Ultraviolet to Infrared Morphology of the Inner Homunculus of η Carinae (2004)
Smith, Nathan, Morse, Jon A., Gull, Theodore R., Hillier, D. John, Gehrz, Robert D., Walborn, Nolan R., ...
We present the first ultraviolet and optical images of η Car and itscircumstellar Homunculus nebula, obtained with the Advanced Camera forSurveys/High Resolution Camera (ACS/HRC) on board the Hubble...
On the Steady Nature of Line-Driven Disk Winds (2003)
Pereyra, Nicolas A., Owocki, Stanley P., Hillier, D. John, Turnshek, David A.
We perform an analytic investigation of the stability of line-driven disk winds, independent of hydrodynamic simulations. Our motive is to determine whether or not line-driven disk winds can account...
Crowther, Paul A., Dessart, Luc, Hillier, D. John, Abbott, Jay B., Fullerton, Alex W.
We use ultraviolet space-based (FUSE, HST) and optical/IR ground-based (2.3m MSSSO, NTT) spectroscopy to determine the physical parameters of six WC4-type Wolf-Rayet stars in the Large Magellanic...
Quantitative analysis of WC stars: Constraints on neon abundances from ISO/SWS spectroscopy (2000)
Dessart, Luc, Crowther, Paul A., Hillier, D. John, Willis, Allan J., Morris, Patrick W., Van Der Hucht, Karel A.
Neon abundances are derived in four Galactic WC stars -- gamma Vel (WR11, WC8+O7.5III), HD156385 (WR90, WC7), HD192103 (WR135, WC8), and WR146 (WC5+O8) - using mid-infrared fine structure lines...