Rainer Lenzen

Near-infrared wavefront sensing for the VLT interferometer (2008)

Hippler, Stefan, Brandner, Wolfgang, Clénet, Yann, Hormuth, Felix, Gendron, Eric, Henning, Thomas, ...

The very large telescope (VLT) interferometer (VLTI) in its current operating state is equipped with high-order adaptive optics (MACAO) working in the visible spectrum. A low-order near-infrared...

METIS - the Mid-infrared E-ELT Imager and Spectrograph (2008)

Brandl, Bernhard R., Lenzen, Rainer, Pantin, Eric, Glasse, Alistair, Blommaert, Joris, Venema, Lars, ...

METIS, the Mid-infrared ELT Imager and Spectrograph (formerly called MIDIR), is a proposed instrument for the European Extremely Large Telescope (E-ELT), currently undergoing a phase-A study. The...

A comprehensive examination of the Eps Eri system -- Verification of a 4 micron narrow-band high-contrast imaging approach for planet searches (2008)

Janson, Markus, Reffert, Sabine, Brandner, Wolfgang, Henning, Thomas, Lenzen, Rainer, Hippler, Stefan

Due to its proximity, youth, and solar-like characteristics with a spectral type of K2V, Eps Eri is one of the most extensively studied systems in an extrasolar planet context. Based on radial...

Constraints on extrasolar planet populations from VLT NACO/SDI and MMT SDI and direct adaptive optics imaging surveys: giant planets are rare at large separations (2008)

Nielsen, Eric L., Close, Laird M., Biller, Beth A., Masciadri, Elena, Lenzen, Rainer

We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast...

LUCIFER status report: summer 2008 (2008)

Mandel, Holger, Seifert, Walter, Hofmann, Reiner, Jütte, Marcus, Lenzen, Rainer, Ageorges, Nancy, ...

LUCIFER is a NIR spectrograph and imager (wavelength range 0.9 to 2.5 micron) for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona, working at cryogenic temperatures of less than 70K. Two...

Near-infrared wavefront sensing for the VLT interferometer (2008)

Hippler, Stefan, Brandner, Wolfgang, Clénet, Yann, Hormuth, Felix, Gendron, Eric, Henning, Thomas, ...

The very large telescope (VLT) interferometer (VLTI) in its current operating state is equipped with high-order adaptive optics (MACAO) working in the visible spectrum. A low-order near-infrared...

METIS: the mid-infrared E-ELT imager and spectrograph (2008)

Brandl, Bernhard R., Lenzen, Rainer, Pantin, Eric, Glasse, Alistair, Blommaert, Joris, Venema, Lars, ...

METIS, the Mid-infrared ELT Imager and Spectrograph (formerly called MIDIR), is a proposed instrument for the European Extremely Large Telescope (E-ELT), currently undergoing a phase-A study. The...

SPHERE: a planet finder instrument for the VLT (2008)

Beuzit, Jean-Luc, Feldt, Markus, Dohlen, Kjetil, Mouillet, David, Puget, Pascal, Wildi, Francois, ...

Direct detection and spectral characterization of extra-solar planets is one of the most exciting but also one of the most challenging areas in modern astronomy. The challenge consists in the very...

PANIC: the new panoramic NIR camera for Calar Alto (2008)

Baumeister, Harald, Alter, Matthias, Cárdenas Vázquez, M. Concepcián, Fernandez, Matilde, Fried, Josef, Helmling, Jens, ...

PANIC is a wide-field NIR camera, which is currently under development for the Calar Alto observatory (CAHA) in Spain. It uses a mosaic of four Hawaii-2RG detectors and covers the spectral range from...

Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations (2007)

Nielsen, Eric L., Close, Laird M., Biller, Beth A., Masciadri, Elena, Lenzen, Rainer

We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast...

NACO-SDI direct imaging search for the exoplanet Eps Eri b (2007)

Janson, Markus, Brandner, Wolfgang, Henning, Thomas, Lenzen, Rainer, McArthur, Barbara, Benedict, G. Fritz, ...

The active K2V star $\epsilon$ Eri hosts the most nearby known extrasolar planet. With an angular separation of about 1" on average, and an age of a few to several hundred Myrs, $\epsilon$ Eri b is...

NACO-SDI direct imaging search for the exoplanet e Eri b (2007)

Janson, Markus, Brandner, Wolfgang, Henning, Thomas, Lenzen, Rainer, McArthur, Barbara, Benedict, G. Fritz, ...

The active K2 V star ɛ Eri hosts the nearest known extrasolar planet. With an angular separation of about 1" on average, and an age of a few to several hundred megayears, ɛ Eri b is one of the...

Improved age constraints for the AB Dor quadruple system - The binary nature of AB Dor B (2006)

Janson, Markus, Brandner, Wolfgang, Lenzen, Rainer, Close, Laird, Nielsen, Eric, Hartung, Markus, ...

We present resolved NACO photometry of the close binary AB Dor B in H- and Ks-band. AB Dor B is itself known to be a wide binary companion to AB Dor A, which in turn has a very low-mass close...

Suppressing Speckle Noise for Simultaneous Differential Extrasolar Planet Imaging (SDI) at the VLT and MMT (2006)

Biller, Beth A., Close, Laird M., Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, Nielsen, Eric, ...

We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a double...

A Survey of Close, Young Stars with the Simultaneous Differential Imager (SDI) at the VLT and MMT (2006)

Biller, Beth A., Close, Laird M., Masciadri, Elena, Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, ...

We discuss the preliminary results of a survey of young ( 10 mag, Delta H > 11.5 mag for a T6 spectral type) at a separation of 0.5" from the primary star. With this degree of attenuation, we should...

Observational capabilities and technical solutions of a thermal and MIR instrument at E-ELT (2006)

Lenzen, Rainer, Brandl, Bernhard, Brandner, Wolfgang, Finger, Gert, Glasse, Alistair, Käufl, Hans-Ulrich, ...

A MIR instrumentation study for a European ELT has been performed by a Dutch consortium led by the Leiden Observatory (The Netherlands) and the Max-Planck-Institut fur Astronomie in Heidelberg...

ELT instrument concepts: impact on telescope and adaptive optics design (2006)

Cunningham, Colin, Atad-Ettadgui, Eli, Bacon, Roland, Brandl, Bernhard, Cuby, Jean-Gabriel, Dalton, Gavin, ...

We report on the development of instrument concepts for a European ELT, expanding on studies carried out as part of the ESO OWL concept. A range of instruments were chosen to demonstrate how an ELT...

MIDIR/T-OWL: the thermal/mid-IR instrument for the E-ELT (2006)

Brandl, Bernhard, Lenzen, Rainer, Venema, Lars, Käufl, Hans-Ulrich, Finger, Gert, Glasse, Alistair, ...

MIDIR is a combined thermal/mid-infrared imager and spectrograph for the European Extremely Large Telescope (EELT). It will operate in the infrared L, M, N, and Q-band to 20mum with a goal to extend...

Contrast limits with the Simultaneous Differential Extrasolar Planet Imager (SDI) at the VLT and MMT (2006)

Biller, Beth A., Close, Laird M., Masciadri, Elena, Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, ...

We discuss contrast limits obtained during a survey of young (10 mag, DeltaH>10.6 mag for a T6 spectral type) at a separation of 0.5" from the primary star. With this degree of attenuation, we can...

Suppressing Speckle Noise for simultaneous differential extrasolar planet imaging (SDI) at the VLT and MMT (2006)

Biller, Beth A., Close, Laird M., Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, Nielsen, Eric, ...

We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a quad filter to...

The Arches Cluster - Evidence for a Truncated Mass Function? (2005)

Stolte, Andrea, Brandner, Wolfgang, Grebel, Eva K., Lenzen, Rainer, Lagrange, Anne-Marie

We have analyzed high-resolution, adaptive optics (AO) HK observations of the Arches cluster obtained with NAOS/CONICA. With a spatial resolution of 84 mas, the cluster center is uniquely resolved....

A dynamical calibration of the mass-luminosity relation at very low stellar masses and young ages (2005)

Close, Laird M., Lenzen, Rainer, Guirado, Jose C., Nielsen, Eric L., Mamajek, Eric E., Brandner, Wolfgang, ...

Mass is the most fundamental parameter of a star, yet it is also one of the most difficult to measure directly. In general, astronomers estimate stellar masses by determining the luminosity and using...

The Arches cluster: Evidence for a truncated mass function? (2005)

Stolte, Andrea, Brandner, Wolfgang, Grebel, Eva K., Lenzen, Rainer, Lagrange, Anne-Marie

We have analyzed high-resolution, adaptive optics HK observations of the Arches cluster obtained with NAOS-CONICA. With a spatial resolution of 84 mas, the cluster center is uniquely resolved. From...

Discovery of a candidate for the central star of the ultracompact H II region G5.89-0.39 (2003)

Feldt, Markus, Puga, Elena, Lenzen, Rainer, Henning, Thomas, Brandner, Wolfgang, Stecklum, B., ...

We present high-resolution, near-infrared images of the ultracompact H II region G5.89-0.39 that were taken during a commissioning run of the NACO adaptive optics/near-infrared camera system at the...