Bruno Leibundgut

Time evolution of the line emission from the inner circumstellar ring of SN 1987A and its hot spots (2008)

Groeningsson, Per, Fransson, Claes, Leibundgut, Bruno, Lundqvist, Peter, Challis, Peter, Chevalier, Roger A., ...

We present seven epochs between October 1999 and November 2007 of high resolution VLT/UVES echelle spectra of the ejecta-ring collision of SN 1987A. The fluxes of most of the narrow lines from the...

Late-Time HST Photometry of SN 1994I: Hints of Positron Annihilation Energy Deposition (2008)

Clocchiatti, Alejandro, Wheeler, J. Craig, Kirshner, Robert P., Branch, David, Challis, Peter, Chevalier, Roger A., ...

We present multicolor Hubble Space Telescope (HST) WFPC2 broadband observations of the Type Ic SN 1994I obtained approximately 280 days after maximum light. We measure the brightness of the SN and,...

Supernovae and Cosmology (2008)

Leibundgut, Bruno

The extreme luminosity and their fairly unique temporal behaviour have made supernovae a superb tool to measure distances in the universe. As complex astrophysical events they provide interesting...

Direct Analysis of Spectra of the Type Ic Supernova 1994I (2007)

Jennifer Millard, David Branch, E. Baron, Adam Fisher, A. V. Filippenko, R. P. Kirshner, ...

Synthetic spectra generated by the parameterized supernova synthetic-- spectrum code SYNOW are compared to observed photospheric--phase spectra of the Type Ic supernova 1994I. The observed optical...

High resolution spectroscopy of the line emission from the inner circumstellar ring of SN 1987A and its hot spots (2007)

Groeningsson, Per, Fransson, Claes, Lundqvist, Peter, Lundqvist, Natalia, Leibundgut, Bruno, Spyromilio, Jason, ...

We discuss high resolution VLT/UVES observations (FWHM ~ 6 km/s) from October 2002 (day ~5700 past explosion) of the shock interaction of SN 1987A and its circumstellar ring. A nebular analysis of...

Infrared Integral Field Spectroscopy of SN 1987A (2007)

Kjaer, Karina, Leibundgut, Bruno, Fransson, Claes, Groeningsson, Per, Spyromilio, Jason, Kissler-Patig, Markus

SN 1987A in the Large Magellanic Cloud is close enough for a study of the very late time evolution of a supernova and its transition to a supernova remnant. Nearly two decades after explosion we are...

SN 1987A at the end of its second decade (2006)

Kjaer, Karina, Groeningsson, Per, Kotak, Rubina, Fransson, Claes, Leibundgut, Bruno

After nearly two decades at least five emission mechanisms can be found in SN 1987A. The ejecta continue to glow as a result of the radioactive decay of long-lived nuclei (mostly 44Ti), but is fading...

Report by the ESA-ESO Working Group on Fundamental Cosmology (2006)

Peacock, John A., Schneider, Peter, Efstathiou, George, Ellis, Jonathan R., Leibundgut, Bruno, Lilly, Simon J., ...

ESO and ESA agreed to establish a number of Working Groups to explore possible synergies between these two major European astronomical institutions. This Working Group's mandate was to concentrate on...

Coronal emission from the shocked circumstellar ring of SN 1987A (2006)

Groeningsson, Per, Fransson, Claes, Lundqvist, Peter, Nymark, Tanja, Lundqvist, Natalia, Chevalier, Roger, ...

High resolution spectra with UVES/VLT of SN 1987A from December 2000 until November 2005 show a number of high ionization lines from gas with velocities of roughly 350 km/s, emerging from the shocked...

Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts (2006)

Blondin, Stéphane, Dessart, Luc, Leibundgut, Bruno, Branch, David, Höflich, Peter, Tonry, John L., ...

Using archival data of low-redshift (z < 0.01; Center for Astrophysics and SUSPECT databases) Type Ia supernovae (SNe Ia) and recent observations of high-redshift (0.16 < z < 0.64) SNe Ia, we study...

Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts (2006)

Blondin, Stéphane, Dessart, Luc, Leibundgut, Bruno, Branch, David, Höflich, Peter, Tonry, John L., ...

Using archival data of low-redshift (z < 0.01; Center for Astrophysics and SUSPECT databases) Type Ia supernovae (SNe Ia) and recent observations of high-redshift (0.16 < z < 0.64) SNe Ia, we study...

Hubble Space Telescope and ground-based observations of type Ia supernovae at redshift 0.5: cosmological implications (2006)

Clocchiatti, Alejandro, Schmidt, Brian P., Filippenko, Alexei V., Challis, Peter, Coil, Alison L., Covarrubias, R., ...

We present observations of the Type I Supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshiftz z ≈ 0.5. They were discovered in early 1999 with the 4.0 m Blanco telescope at Cerro...

Hubble Space Telescope and ground-based observations of type Ia supernovae at redshift 0.5: cosmological implications (2006)

Clocchiatti, Alejandro, Schmidt, Brian P., Filippenko, Alexei V., Challis, Peter, Coil, Alison L., Covarrubias, R., ...

We present observations of the Type I Supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshiftz z ≈ 0.5. They were discovered in early 1999 with the 4.0 m Blanco telescope at Cerro...

Supernova Cosmology and the ESSENCE project (2005)

Sollerman, Jesper, Aguilera, Claudio, Becker, Andy, Blondin, Stephane, Challis, Pete, Clocchiatti, Alejandro, ...

The proper usage of Type Ia supernovae (SNe Ia) as distance indicators has revolutionized cosmology, and added a new dominant component to the energy density of the Universe, dark energy. Following...

Constraints on the Progenitor Systems of Type Ia Supernovae (2005)

Stritzinger, Maximilian, Leibundgut, Bruno, Walch, Stefanie, Contardo, Gertrud

UVOIR bolometric light curves provide valuable insight into the nature of type Ia supernovae. We present an analysis of sixteen well-observed SNe Ia. Constraints are placed on several global...

Hubble Space Telescope and Ground-Based Observations of SN 1993J and SN 1998S: CNO Processing in the Progenitors (2004)

Fransson, Claes, Challis, Peter M., Chevalier, Roger A., Filippenko, Alexei V., Kirshner, Robert P., Kozma, Cecilia, ...

Ground-based and Hubble Space Telescope observations are presented for SN 1993J and SN 1998S. SN 1998S shows strong, relatively narrow circumstellar emission lines of N III-V and C III-IV, as well as...

The late-time light curve of the Type Ia supernova 2000cx (2004)

Sollerman, Jesper, Lindahl, Jan, Kozma, Cecilia, Challis, Peter, Filippenko, Alexei V., Fransson, Claes, ...

We have conducted a systematic and comprehensive monitoring programme of the Type Ia supernova 2000cx at late phases using the VLT and HST. The VLT observations cover phases 360 to 480 days past...

Diffuse Interstellar Bands in NGC 1448 (2004)

Sollerman, Jesper, Cox, Nick, Mattila, Seppo, Ehrenfreund, Pascale, Kaper, Lex, Leibundgut, Bruno, ...

We present spectroscopic VLT/UVES observations of two emerging supernovae, the Type Ia SN 2001el and the Type II SN 2003hn, in the spiral galaxy NGC 1448. Our high resolution and high signal-to-noise...

Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution (2004)

Riess, Adam G., Strolger, Louis-Gregory, Tonry, John, Casertano, Stefano, Ferguson, Henry C., Mobasher, Bahram, ...

We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to provide the first conclusive evidence for cosmic deceleration that preceded the current...

23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7 (2003)

Barris, Brian J., Tonry, John, Blondin, Stephane, Challis, Peter, Chornock, Ryan, Clocchiatti, Alejandro, ...

We present photometric and spectroscopic observations of 23 high redshift supernovae spanning a range of z=0.34-1.03, 9 of which are unambiguously classified as Type Ia. These supernovae were...

Imaging and Demography of the Host Galaxies of High-Redshift Type Ia Supernovae (2003)

Williams, Benjamin F., Hogan, Craig J., Barris, Brian, Candia, Pablo, Challis, Peter, Clocchiatti, Alejandro, ...

We present the results of a study of the host galaxies of high redshift Type Ia supernovae (SNe Ia). We provide a catalog of 18 hosts of SNe Ia observed with the Hubble Space Telescope (HST) by the...

High-resolution optical studies of nearby Type Ia supernovae (2003)

Lundqvist, Peter, Mattila, Seppo, Sollerman, Jesper, Baron, E., Ehrenfreund, Pascale, Fransson, Claes, ...

Since April 2000, a program using the ESO/VLT/UVES to search for early circumstellar signatures from nearby supernovae has been conducted. Until now, two Type Ia supernovae have been observed, SNe...

Identification of Type Ia Supernovae at Redshift 1.3 and Beyond with the Advanced Camera for Surveys on HST (2003)

Riess, Adam G., Strolger, Louis-Gregory, Tonry, John, Tsvetanov, Zlatan, Casertano, Stefano, Ferguson, Henry C., ...

We present discoveries of SNe Ia at z > 1 and the photometric diagnostic used to discriminate them from other types of SNe detected during the GOODS Hubble Space Telescope Treasury program with the...

Cosmological Results from High-z Supernovae (2003)

Tonry, John L., Schmidt, Brian P., Barris, Brian, Candia, Pablo, Challis, Peter, Clocchiatti, Alejandro, ...

The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z=0.3-1.2. These independent observations, confirm the result of Riess et al. (1998a) and...

Optical Light Curves of Supernovae (2003)

Leibundgut, Bruno, Suntzeff, Nicholas B.

Photometry is the most easily acquired information about supernovae. The light curves constructed from regular imaging provide signatures not only for the energy input, the radiation escape, the...

A cosmological surprise: the universe accelerates (2002)

Leibundgut, Bruno, Sollerman, Jesper

Review article on the cosmological implications of Type Ia Supernovae for Europhysics News.

Modelling the Hubble Space Telescope Ultraviolet and Optical Spectrum of Spot 1 on the Circumstellar Ring of SN 1987A (2002)

Pun, Chun S. J., Michael, Eli, Zhekov, Svetozar A., McCray, Richard, Garnavich, Peter M., Challis, Peter M., ...

We report and interpret HST/STIS long-slit observations of the optical and ultraviolet (1150 - 10270 Angstrom) emission-line spectra of the rapidly brightening Spot 1 on the equatorial ring of SN...

Optical and Ultraviolet Spectroscopy of SN 1995N: Evidence for Strong Circumstellar Interaction (2001)

Fransson, Claes, Chevalier, Roger A., Filippenko, Alexei V., Leibundgut, Bruno, Barth, Aaron J., Fesen, Robert A., ...

Optical and ultraviolet observations of the Type IIn supernova 1995N at epochs between 321 and 1799 days after the explosion show three distinct velocity components. The narrow lines come from...

The metamorphosis of SN1998bw (2001)

Patat, Ferdinando, Cappellaro, Enrico, Danziger, John, Mazzali, Paolo A., Sollerman, Jesper, Augusteijn, Thomas, ...

We present and discuss the photometric and spectroscopic evolution of the peculiar SN1998bw, associated with GRB980425, through an analysis of optical and near IR data collected at ESO-La Silla. The...

Preliminary Spectral Analysis of the Type II Supernova 1999em (2000)

Baron, E., Branch, David, Hauschildt, Peter H., Filippenko, Alexei V., Kirshner, R. P., Challis, P. M., ...

We have calculated fast direct spectral model fits to two early-time spectra of the Type-II plateau SN 1999em, using the SYNOW synthetic spectrum code. The first is an extremely early blue optical...

Analysis of the Type IIn Supernova 1998S: Effects of Circumstellar Interaction on Observed Spectra (2000)

Lentz, Eric J., Baron, E., Lundqvist, Peter, Branch, David, Hauschildt, Peter H., Fransson, Claes, ...

We present spectral analysis of early observations of the Type IIn supernova 1998S using the general non-local thermodynamic equilibrium atmosphere code \tt PHOENIX}. We model both the underlying...

SN 1998bw at late phases (2000)

Sollerman, Jesper, Kozma, Cecilia, Fransson, Claes, Leibundgut, Bruno, Lundqvist, Peter, Ryde, Felix, ...

We present observations of the peculiar supernova SN 1998bw, which was probably associated with GRB 980425. The photometric and spectroscopic evolution is monitored up to 500 days past explosion. We...

Type Ia Supernovae (2000)

Leibundgut, Bruno

Type Ia Supernovae are in many aspects still enigmatic objects. Recent years have witnessed a bonanza of supernova observations. The increased samples from dedicated searches have allowed the...

The High-Redshift Supernova Search -- Evidence for a Positive Cosmological Constant (1998)

Leibundgut, Bruno, Contardo, Gertrud, Woudt, Patrick, Spyromilio, Jason

A new component of the Universe which leads to an accelerated cosmic expansion is found from the measurements of distances to high-redshift type Ia supernovae. We describe the method and the results...

Deep optical observations at the position of PSR1706-44 with the VLT-UT1 (1998)

Lundqvist, Peter, Sollerman, Jesper, Ray, Alak, Leibundgut, Bruno, Sutaria, Firoza

We present optical data gathered by the VLT Test Camera in the V-band at the radio (interferometric) position of PSR1706-44. We find no optical counterpart to the pulsar in the VLT image. At a...

A Deep Optical Luminosity Function of NGC 6712 with the VLT: Evidence for Severe Tidal Disruption (1998)

De Marchi, Guido, Leibundgut, Bruno, Paresce, Francesco, Pulone, Luigi

The VLT on Cerro Paranal was used to observe four fields located at 2.3' from the center of the Galactic globular cluster NGC 6712 in the V and R bands. The resulting color-magnitude diagram shows a...

Late-Time Optical and UV Spectra of SN 1979C and SN 1980K (1998)

Fesen, Robert A., Gerardy, Christopher L., Filippenko, Alexei V., Matheson, Thomas, Chevalier, Roger A., Kirshner, Robert P., ...

A low-dispersion Keck I spectrum of SN 1980K taken in August 1995 (t = 14.8 yr after explosion) and a November 1997 MDM spectrum (t = 17.0 yr) show broad 5500 km s^{-1} emission lines of H\alpha, [O...

Hubble Space Telescope WFPC2 Imaging of SN 1979C and Its Environment (1998)

Van Dyk, Schuyler D., Peng, Chien Y., Barth, Aaron J., Filippenko, Alexei V., Chevalier, Roger A., Fesen, Robert A., ...

The locations of supernovae in the local stellar and gaseous environment in galaxies contain important clues to their progenitor stars. As part of a program to study the environments of supernovae...

Emission within a Damped Lyman Alpha Absorption Trough: the Complex Sight Line Towards Q2059-360 (1998)

Leibundgut, Bruno, Robertson, J. Gordon

We present new spectroscopic observations of the quasar Q2059-360, confirming the existence of an emission feature within the Damped Lyman Alpha (DLA) absorption trough. By observing also at slit...

The Rise Times and Bolometric Light Curve of SN 1994D: Constraints on Models of Type Ia Supernovae (1996)

Vacca, William D., Leibundgut, Bruno

Using the published photometry and an empirical model of the temporal evolution of the apparent magnitudes in the UBVRI passbands, we have constructed a continuous optical bolometric, or...

TYPE Ib/c SUPERNOVAE AND THEIR RELATION TO BINARY STARS (1995)

Leibundgut, Bruno

The present understanding of type Ib/c supernovae and their connection to interacting binaries is reviewed. The problems of the classification and the lack of well-observed events exclude direct...

SN~1991T: Reflections of Past Glory (1994)

Schmidt, Brian P., Kirshner, Robert P., Leibundgut, Bruno, Wells, Lisa A., Porter, Alain C., Ruiz-Lapuente, Pilar, ...

We have obtained photometry and spectra of SN~1991T which extend more than 1000 days past maximum light, by far the longest a SN~Ia has been followed. Although SN~1991T exhibited nearly normal...