Wolfgang Brandner

Search for very low-mass brown dwarfs and free-floating planetary-mass objects in Taurus (2009)

Quanz, Sascha P., Goldman, Bertrand, Henning, Thomas, Brandner, Wolfgang, Burrows, Adam, Hofstetter, Lorne W.

The number of low-mass brown dwarfs and even free floating planetary mass objects in young nearby star-forming regions and associations is continuously increasing, offering the possibility to study...

Recent Star Formation in Low Metallicities. The Star-Forming Region NGC 346/N66 in the Small Magellanic Cloud from Near-Infrared VLT/ISAAC Observations (2009)

Gouliermis, Dimitrios A., Bestenlehner, Joachim M., Brandner, Wolfgang, Henning, Thomas, Rubio, Monica, Barba, Rodolfo H.

We perform a photometric analysis on deep, seeing-limited near-IR VLT images of the region NGC 346/N66 and a nearby control field of the SMC in order to locate the centres of active high- and...

The Evolution Of Massive Young Stellar Objects in the Large Magellanic Cloud. I. Identification and Spectral Classification (2009)

Seale, Jonathan P., Looney, Leslie W., Chu, You-Hua, Gruendl, Robert A., Brandl, Bernhard, Chen, C.-H. Rosie, ...

We present and categorize Spitzer infrared spectrometer spectra of 294 objects in the Large Magellanic Cloud (LMC) to create the largest and most complete catalog of massive young stellar object...

The Evolution of Massive YSOs in the LMC: Part I. Identification and Spectral Classification (2009)

Seale, Jonathan P., Looney, Leslie W., Chu, You-Hua, Gruendl, Robert A., Brandl, Bernhard, Chen, C. -H. Rosie, ...

We present and categorize Spitzer IRS spectra of 294 objects in the Large Magellanic Cloud (LMC) to create the largest and most complete catalog of massive young stellar object (YSO) spectra in the...

Testing the models: NIR imaging and spectroscopy of the benchmark T-dwarf binary Eps Indi B (2009)

Kasper, Markus, Burrows, Adam, Brandner, Wolfgang

The relative roles of metallicity and surface gravity on the near-infrared spectra of late-T brown dwarfs are not yet fully understood, and evolutionary models still need to be calibrated in order to...

The AstraLux large M dwarf survey (2008)

Hormuth, Felix, Brandner, Wolfgang, Janson, Markus, Hippler, Stefan, Henning, Thomas

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope and the 3.5-m NTT at La Silla. It allows nearly diffraction limited imaging in the SDSS i' and z' bands of objects as faint as...

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...

AstraLux: the Calar Alto Lucky Imaging Camera (2008)

Hormuth, Felix, Hippler, Stefan, Brandner, Wolfgang, Wagner, Karl, Henning, Thomas

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope, based on an electron-multiplying high speed CCD. By selecting only the best 1-10% of several thousand short exposure frames,...

AstraLux - the Calar Alto 2.2-m telescope Lucky Imaging camera (2008)

Hormuth, Felix, Brandner, Wolfgang, Hippler, Stefan, Henning, Thomas

AstraLux is a Lucky Imaging camera for the Calar Alto 2.2-m telescope, based on an electron-multiplying high speed CCD. By selecting only the best 1-10% of several thousand short exposure frames,...

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...

Westerlund 1 and its Galactic siblings -Observation confronts Theory (2008)

Brandner, Wolfgang

Because of their large number of stars spread over the entire stellar mass spectrum, starburst clusters are highly suitable to benchmark and calibrate star formation models and theories. Among the...

Dense molecular gas in a young cluster around MWC 1080: rule of the massive star (2008)

Wang, Shiya, Looney, Leslie W., Brandner, Wolfgang, Close, Laird M.

We present CS J=2-->1, 13CO J=1-->0, and C18O J=1-->0, observations with the 10 element Berkeley Illinois Maryland Association (BIMA) array toward the young cluster around the Be star MWC 1080. These...

The orbital motion of the Arches cluster --- clues on cluster formation near the galactic center (2008)

Stolte, Andrea, Ghez, Andrea M., Morris, Mark R., Lu, Jessica R., Brandner, Wolfgang, Matthews, Keith

The Arches cluster is one of the most massive, young clusters in the Milky Way. Located inside the central molecular zone in the inner 200 pc of the Galactic center, it formed in one of the most...

Opto-mechanical design of the spectrometers of GRAVITY: the 6-baseline K-band interferometer for the VLTI (2008)

Straubmeier, Christian, Eisenhauer, Frank, Perrin, Guy, Brandner, Wolfgang, Eckart, Andreas

GRAVITY is a 2nd generation VLTI instrument that operates in the K-band and uses up to 4 telescopes simultaneously. GRAVITY will provide interferometric astrometry of two objects in a 2 arcsecond...

NGC 346 in the Small Magellanic Cloud. IV. Triggered star formation in the H II region N66 (2008)

Gouliermis, Dimitrios A., Chu, You-Hua, Henning, Thomas, Brandner, Wolfgang, Gruendl, Robert A., Hennekemper, Eva, ...

Stellar feedback, expanding H II regions, wind-blown bubbles, and supernovae are thought to be important triggering mechanisms of star formation. Stellar associations, being hosts of significant...

The rapid outbursting star GM Cep: an EXor in Tr 37? (2008)

Sicilia-Aguilar, Aurora, Merí­n, Bruno, Hormuth, Felix, Ãbrahám, Peter, Henning, Thomas, Kun, Mária, ...

We present optical, IR, and millimeter observations of the solar-type star 13-277, also known as GM Cep, in the 4 Myr old cluster Tr 37. GM Cep experiences rapid magnitude variations of more than 2...

Fringe detection laser metrology for differential astrometric stellar interferometers (2008)

Rabien, S., Gillessen, S., Ziegleder, J., Thiel, Markus, Gräter, Alex, Haug, Marcus, ...

Differential measurements with dual feed stellar interferometers using large baselines can deliver extremely accurate astrometric data. Separating the phase difference measured on the stars from the...

AstraLux: the Calar Alto lucky imaging camera (2008)

Hormuth, Felix, Hippler, Stefan, Brandner, Wolfgang, Wagner, Karl, Henning, Thomas

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope, based on an electron-multiplying high speed CCD. By selecting only the best 1-10% of several thousand short exposure frames,...

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...

NGC 346 in the Small Magellanic Cloud. III. Recent star formation and stellar clustering properties in the bright H II region N66 (2008)

Hennekemper, Eva, Gouliermis, Dimitrios A., Henning, Thomas, Brandner, Wolfgang, Dolphin, Andrew E.

In the third part of our photometric study of the star-forming region NGC 346/N66 and its surrounding field in the Small Magellanic Cloud (SMC), we focus on the large number of low-mass...

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...

The orbital motion of the Arches cluster — clues on cluster formation near the galactic center (2008)

Stolte, Andrea, Ghez, Andrea M., Morris, Mark R., Lu, Jessica R., Brandner, Wolfgang, Matthews, Keith

The Arches cluster is one of the most massive, young clusters in the Milky Way. Located inside the central molecular zone in the inner 200 pc of the Galactic center, it formed in one of the most...

Intermediate to low-mass stellar content of Westerlund 1 (2007)

Brandner, Wolfgang, Clark, J. Simon, Stolte, Andrea, Waters, Rens, Negueruela, Ignacio, Goodwin, Simon P.

We have analysed near-infrared NTT/SofI observations of the starburst cluster Westerlund 1, which is among the most massive young clusters in the Milky Way. A comparison of colour-magnitude diagrams...

Integral field spectroscopy of L 449-1 -- A test case for spectral differential imaging with SINFONI (2007)

Janson, Markus, Brandner, Wolfgang, Henning, Thomas

Spectral differential imaging is an increasingly used technique for ground-based direct imaging searches for brown dwarf and planetary mass companions to stars. The technique takes advantage of...

The Rapid Outbursting Star GM Cep: An EX-or in Tr 37? (2007)

Sicilia-Aguilar, Aurora, Merin, Bruno, Hormuth, Felix, Abraham, Peter, Henning, Thomas, Kun, Maria, ...

We present optical, IR and millimeter observations of the solar-type star 13-277, also known as GM Cep, in the 4 Myr-old cluster Tr 37. GM Cep experiences rapid magnitude variations of more than 2...

NGC 346 in The Small Magellanic Cloud. IV. Triggered Star Formation in the HII Region N66 (2007)

Gouliermis, Dimitrios A., Chu, You-Hua, Henning, Thomas, Brandner, Wolfgang, Gruendl, Robert A., Hennekemper, Eva, ...

Stellar feedback, expanding HII regions, wind-blown bubbles, and supernovae are thought to be important triggering mechanisms of star formation. Stellar associations, being hosts of significant...

NGC 346 in the Small Magellanic Cloud. III. Recent Star Formation and Stellar Clustering Properties in the Bright HII Region N 66 (2007)

Hennekemper, Eva, Gouliermis, Dimitrios A., Henning, Thomas, Brandner, Wolfgang, Dolphin, Andrew E.

In the third part of our photometric study of the star-forming region NGC 346/N~66 and its surrounding field in the Small Magellanic Cloud (SMC), we focus on the large number of low-mass pre-main...

Dense Molecular Gas In A Young Cluster Around MWC 1080 -- Rule Of The Massive Star (2007)

Wang, Shiya, Looney, Leslie W., Brandner, Wolfgang, Close, Laird M.

We present CS $J = 2 \to 1$, $^{13}$CO $J = 1 \to 0$, and C$^{18}$O $J = 1 \to 0$, observations with the 10-element Berkeley Illinois Maryland Association (BIMA) Array toward the young cluster around...

Discovery of the Pre-Main Sequence Population of the Stellar Association LH 95 in the Large Magellanic Cloud with Hubble Space Telescope ACS Observations (2007)

Gouliermis, Dimitrios A., Henning, Thomas, Brandner, Wolfgang, Dolphin, Andrew E., Rosa, Michael, Brandl, Bernhard

We report the discovery of an extraordinary number of pre-main sequence (PMS) stars in the vicinity of the stellar association LH 95 in the Large Magellanic Cloud (LMC). Using the {\em Advanced...

The proper motion of the Arches cluster with Keck Laser-Guide Star Adaptive Optics (2007)

Stolte, Andrea, Ghez, Andrea M., Morris, Mark, Lu, Jessica R., Brandner, Wolfgang, Matthews, Keith

We present the first measurement of the proper motion of the young, compact Arches cluster near the Galactic center from near-infrared adaptive optics (AO) data taken with the recently commissioned...

The very nearby M/T dwarf binary SCR 1845-6357 (2007)

Kasper, Markus, Biller, Beth A., Burrows, Adam, Brandner, Wolfgang, Budaj, Jano, Close, Laird M.

The recently discovered star SCR 1845-6357 is the first late M/T dwarf binary discovered. SCR 1845 is a particular object due to its tight orbit (currently around 4 AU) and its proximity to the Sun...

A novel L-band imaging search for giant planets in the Tucana and Beta Pictoris moving groups (2007)

Kasper, Markus, Apai, Daniel, Janson, Markus, Brandner, Wolfgang

The paper presents results from a small survey of 22 young, nearby stars that was designed to detect substellar companions and ultimately giant extrasolar planets down to Jupiter masses. The targets...

The Star-forming Region NGC 346 in the Small Magellanic Cloud with Hubble Space Telescope ACS Observations. II. Photometric Study of the Intermediate-Age Star Cluster BS 90 (2007)

Rochau, Boyke, Gouliermis, Dimitrios A., Brandner, Wolfgang, Dolphin, Andrew E., Henning, Thomas

We present the results of our investigation of the intermediate-age star cluster BS 90, located in the vicinity of the HII region N 66 in the SMC, observed with HST/ACS. The high-resolution data...

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...

DENSE MOLECULAR GAS IN A YOUNG CLUSTER AROUND MWC1080 -- OBSERVATIONAL EVIDENCE FOR CLOUD SHREDDING (2007)

Wang, Shiya, Looney, L. W., Brandner, Wolfgang, Close, Laird M.

Author Institution: Department of Astronomy, University of Illinois,; 1002 W. Green St., Urbana, IL 61801; Max-Planck-Institut fur Astronomie in Heidelberg, Germany; Steward Observatory, University...

The star-forming region NGC 346 in the Small Magellanic Cloud with Hubble Space Telescope ACS observations. II. Photometric study of the intermediate-age star cluster BS 90 (2007)

Rochau, Boyke, Gouliermis, Dimitrios A., Brandner, Wolfgang, Dolphin, Andrew E., Henning, Thomas

We present the results of our investigation of the intermediate-age star cluster BS 90, located in the vicinity of the H II region N66 in the SMC, observed with HST ACS. The high-resolution data...

A novel L-band imaging search for giant planets in the Tucana and b Pictoris moving groups (2007)

Kasper, Markus, Apai, Daniel, Janson, Markus, Brandner, Wolfgang

The paper presents results from a small survey of 22 young, nearby stars that was designed to detect substellar companions and ultimately giant extrasolar planets down to Jupiter masses. The targets...

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...

Discovery of the pre-main-sequence population of the stellar association LH 95 in the Large Magellanic Cloud with Hubble Space Telescope advanced camera for surveys observations (2007)

Gouliermis, Dimitrios A., Henning, Thomas, Brandner, Wolfgang, Dolphin, Andrew E., Rosa, Michael, Brandl, Bernhard

We report the discovery of an extraordinary number of pre-main-sequence (PMS) stars in the vicinity of the stellar association LH 95 in the Large Magellanic Cloud (LMC). Using the Advanced Camera for...

Direct imaging of the young spectroscopic binary HD 160934 (2006)

Hormuth, Felix, Brandner, Wolfgang, Hippler, Stefan, Janson, Markus, Henning, Thomas

We report on the direct detection of a close companion to HD 160934, a young active star, SB1 spectroscopic binary, and suggested member of the AB Doradus moving group. High angular resolution at 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...

Atmosphere-like turbulence generation with surface-etched phase-screens (2006)

Hippler, Stefan, Hormuth, Felix, Butler, David J., Brandner, Wolfgang, Henning, Thomas

We built and characterized an optical system that emulates the optical characteristics of an 8m-class telescope like the Very Large Telescope. The system contains rotating glass phase-screens to...

High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks (2006)

Sicilia-Aguilar, Aurora, Hartmann, Lee, Furezs, Gabor, Henning, Thomas, Dullemond, Cornelis, Brandner, Wolfgang

Using the Hectochelle multifiber spectrograph, we have obtained high-resolution (R~34,000) spectra in the Halpha region for a large number of stars in the 4 Myr-old cluster Tr 37, containing 146...

The secrets of the nearest starburst cluster: II. The present-day mass function in NGC 3603 (2006)

Stolte, Andrea, Brandner, Wolfgang, Brandl, Bernhard, Zinnecker, Hans

Based on deep VLT/ISAAC JHK photometry, we have derived the present-day mass function of the central starburst cluster NGC 3603 YC (Young Cluster) in the giant HII region NGC 3603. The effects of...

Early ComeOn+ Adaptive Optics Observation of GQ Lup and its Substellar Companion (2006)

Janson, Markus, Brandner, Wolfgang, Henning, Thomas, Zinnecker, Hans

An analysis of adaptive optics K-band imaging data of GQ Lup acquired in 1994 by the first generation adaptive optics system ComeOn+ at the ESO 3.6m optical telescope in La Silla is presented. The...

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...

The secrets of the nearest starburst cluster. II. The present-day mass function in NGC 3603 (2006)

Stolte, Andrea, Brandner, Wolfgang, Brandl, Bernhard, Zinnecker, Hans

Based on deep Very Large Telescope Infrared Spectrometer and Array Camera JHK photometry, we have derived the present-day mass function (MF) of the central starburst cluster NGC 3603 YC (Young...

High-resolution spectroscopy in Tr 37: Gas accretion evolution in evolved dusty disks (2006)

Sicilia-Aguilar, Aurora, Hartmann, Lee W., Fürész, Gábor, Henning, Thomas, Dullemond, Cornelis, Brandner, Wolfgang

Using the Hectochelle multifiber spectrograph, we have obtained high-resolution (R~34,000) spectra in the Halpha region for a large number of stars in the 4 Myr old cluster Tr 37, containing 146...

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...

Planet Formation (2006)

Klahr, Hubert, Brandner, Wolfgang

This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our solar system in particular. Drawing from recent advances in observational,...

Atmosphere-like turbulence generation with surface-etched phase-screens (2006)

Hippler, Stefan, Hormuth, Felix, Butler, David J., Brandner, Wolfgang, Henning, Thomas

We built and characterized an optical system that emulates the optical characteristics of an 8m-class telescope like the Very Large Telescope. The system contains rotating glass phase-screens to...

The MPIA multipurpose laboratory atmospheric turbulence simulator MAPS (2006)

Hippler, Stefan, Hormuth, Felix, Brandner, Wolfgang, Butler, David J., Henning, Thomas, Egner, Sebastian

We built an optical system that emulates the optical characteristics of an 8m-class telescope like the VLT and that contains rotating glass plates phase screens to generate realistic atmosphere-like...

The search for the sub-solar initial mass function in the Local Group (2006)

Gouliermis, Dimitrios, Berton, Alessandro, Brandner, Wolfgang, Henning, Thomas, Feldt, Markus

The stellar Initial Mass Function (IMF) is a quantity which accounts for the distribution of the masses of stars, when they are formed. All the information available on the IMF in the low-mass regime...

Exoplanet detection techniques - from astronomy to astrobiology (2006)

Brandner, Wolfgang

Not Available Aims.Properties of multiplicity, such as the multiplicity frequency, the distribution of mass ratios and periods, provide important informations on the formation processes at work....

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...

Halo Mass Function: Low-mass Stars in Deep Fields (2004)

Brandner, Wolfgang

Deep fields are unique probes of the Galactic halo. With a limiting magnitude of, e.g., I = 30 mag, all stars down to the hydrogen-burning limit are detected out to distances of 10 kpc, while stars...

Binaries among Ultra-cool Dwarfs and Brown Dwarfs (2004)

Brandner, Wolfgang, Bouy, Herve, Martin, Eduardo L., Umbreit, Stefan

Observations of brown dwarfs provide important feedback on theories of atmospheres and inner structure of substellar objects. Brown dwarf binary systems furthermore offer the unique opportunity to...

Near-IR observations of UCHII regions (2004)

Alvarez, Carlos, Feldt, Markus, Henning, Thomas, Puga, Elena, Brandner, Wolfgang, Stecklum, Bringfried

We present adaptive-optics (AO) assisted J, H and K/K' images of 8 UCHII regions taken with the ALFA and ADONIS AO systems at Calar Alto and La Silla observatories. The images show details of the...

The secrets of the nearest starburst cluster. I. Very Large Telescope/ISAAC photometry of NGC 3603 (2004)

Stolte, Andrea, Brandner, Wolfgang, Brandl, Bernhard, Zinnecker, Hans, Grebel, Eva K.

VLT/ISAAC JHKL photometry with subarcsecond resolution of the dense, massive starburst cluster NGC 3603 YC forming the core of the NGC 3603 giant molecular cloud is analyzed to reveal characteristics...

Adaptive Optics in Star Formation (2003)

Brandner, Wolfgang

Over the past ten years, the concept of adaptive optics has evolved from early experimental stages to a standard observing tool now available at almost all major optical and near-infrared telescope...

Multiplicity of Nearby Free-floating Ultra-cool Dwarfs: a HST-WFPC2 search for companions (2003)

Bouy, Herve, Brandner, Wolfgang, Martin, Eduardo L., Delfosse, Xavier, Allard, France, Basri, Gibor

We present HST/WFPC2 observations of a sample of 134 ultra-cool objects (spectral types later than M7) coming from the DENIS, 2MASS and SDSS surveys, with distances estimated to range from 7 pc to...

The Mass function of the Arches cluster from Gemini adaptive optics data (2003)

Stolte, Andrea, Grebel, Eva, Brandner, Wolfgang, Figer, Donald

"Galactic Star Formation Across the Stellar Mass Spectrum", proceedings of the 2002 International Astronomical Observatories [IAOC]. Astronomical Society of the Pacific Conference Series....

The mass function of the Arches cluster from Gemini adaptive optics data (2003)

Stolte, Andrea, Grebel, Eva, Brandner, Wolfgang, Figer, Donald

"Galactic Star Formation Across the Stellar Mass Spectrum", proceedings of the 2002 International Astronomical Observatories [IAOC]. Astronomical Society of the Pacific Conference Series....

Multiplicity of nearby free-floating ultracool dwarfs: A Hubble Space Telescope WFPC2 search for companions (2003)

Bouy, Hervé, Brandner, Wolfgang, Martín, Eduardo L., Delfosse, Xavier, Allard, France, Basri, Gibor

We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) observations of a sample of 134 ultracool objects (spectral types later than M7) coming from the Deep Near Infrared...

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...

VLT spectra of the companion candidate Cha Ha 5/cc 1 (2002)

Neuhaeuser, Ralph, Guenther, Eike, Brandner, Wolfgang

We obtained optical and infrared spectra of Cha Ha 5/cc 1, a faint possibly sub-stellar companion candidate next to the M6-type brown dwarf candidate Cha Ha 5 in Cha I, using FORS1 and ISAAC at the...

HST, VLT, and NTT imaging search for wide companions to bona-fide and candidate brown dwarfs in the Cha I dark cloud (2002)

Neuhaeuser, Ralph, Brandner, Wolfgang, Alves, Joao, Joergens, Viki, Comeron, Fernando

We present results from a deep imaging search for companions around the young bona-fide and candidate brown dwarfs Cha Ha 1 to 12 in the Cha I dark cloud, performed with HST WFPC2 (R, I, Ha), VLT...

The Mass Function of the Arches Cluster from Gemini Adaptive Optics Data (2002)

Stolte, Andrea, Grebel, Eva K., Brandner, Wolfgang, Figer, Donald F.

We present the mass function (MF) of the Arches cluster obtained from ground-based adaptive optics data in comparison with results derived from HST/NICMOS data. A MF slope of Gamma = -0.8 +- 0.2 is...

Imaging and spectroscopy of DENIS-P J104814-395606 (2002)

Neuhaeuser, Ralph, Guenther, Eike, Alves, Joao, Grosso, Nicolas, Leinert, Christoph, Ratzka, Thorsten, ...

We obtained deep H- and K-band images of DENIS-P J104814-395606 using SofI and the speckle camera SHARP-I at the ESO-3.5m-NTT as well as QUIRC at the Mauna Kea 2.2m telescope between December 2000...

An Adaptive Optics Survey of M8-M9 Stars: Discovery of 4 Very Low mass Binaries With at Least One System Containing a Brown Dwarf Companion (2002)

Close, Laird M., Siegler, Nick, Potter, Dan, Brandner, Wolfgang, Liebert, James

Use of the highly sensitive Hokupa'a/Gemini curvature wavefront sensor has allowed for the first time direct adaptive optics (AO) guiding on M8-M9 very low mass (VLM) stars. An initial survey of 20...

NGC 3603 - a local template for massive young clusters (2002)

Brandl, Bernhard R., Brandner, Wolfgang, Eisenhauer, Frank, Moffat, Anthony F. J., Palla, Francesco, Zinnecker, Hans

We present a study of the star cluster associated with the massive Galactic HII region NGC 3603 based on near-IR broad- and narrowband observations taken with ISAAC/VLT under excellent seeing...

The Evolution of Circumstellar Disks: Lessons from the VLT and ISO (2001)

Brandner, Wolfgang, Potter, Dan, Sheppard, Scott S., Moneti, Andrea, Zinnecker, Hans

There is strong evidence that the planets in the solar system evolved from a disk-shaped solar nebula ~4.56 Gyr ago. By studying young stars in various evolutionary stages, one aims at tracing back...

Observing the planet formation time-scale by ground-based direct imaging of planetary companions to young nearby stars: Gemini/Hokupa'a image of TWA-5 (2001)

Neuhaeuser, Ralph, Potter, Dan, Brandner, Wolfgang

Many extra-solar planets and a few planetary systems have been found indirectly by small periodic radial velocity variations around old nearby stars. The orbital characteristics of most of them are...

Multiplicity of young brown dwarfs in Cha I (2001)

Joergens, V., Guenther, E., Neuhäuser, R., Comerón, F., Huélamo, N., Alves, J., ...

How frequent are brown dwarf binaries? Do brown dwarfs have planets? Are current theoretical pre-main-sequence evolutionary tracks valid down to the substellar regime? - Any detection of a companion...

HST/NICMOS detection of a partially embedded, intermediate-mass pre-main-sequence population in the 30 Doradus Nebula (2001)

Brandner, Wolfgang, Grebel, Eva K., Barba, Rodolfo H., Walborn, Nolan R., Moneti, Andrea

We present the detection of an intermediate-mass pre-main-sequence population embedded in the nebular filaments surrounding the 30 Doradus region in the Large Magellanic Cloud (LMC) using HST/NICMOS....

Ground-based exoplanet near-infrared search by imaging and spectroscopy: 3 new companion candidates in TWA (2001)

Neuhaeuser, Ralph, Huelamo, Nuria, Guenther, Eike W., Brandner, Wolfgang, Alves, Joao, Comeron, Fernando, ...

We report first results from our ground-based infrared imaging search for sub-stellar companions (brown dwarfs and giant planets) of young (up to 100 Myrs) nearby (up to 100 pc) stars, where...

Probing the Substellar Regime with SIRTF (2000)

Martin, Eduardo L., Brandner, Wolfgang, Jewitt, David, Simon, Theodore, Wainscoat, Richard, Marley, Mark, ...

One of the main scientific drivers of the Space InfraRed Telescope Facility (SIRTF) is the search for brown dwarfs and extrasolar superplanets. We discuss observational strategies for identification...

HST/NICMOS Imaging of Disks and Envelopes Around Very Young Stars (1999)

Padgett, Deborah L., Brandner, Wolfgang, Stapelfeldt, Karl R., Strom, Stephen E., Terebey, Susan, Koerner, David

We present HST/NICMOS observations with 0.1" (15 AU) resolution of six young stellar objects in the Taurus star-formation region. The targets of our survey are three Class I IRAS sources (IRAS...

Kinematics of T Tauri stars in Chamaeleon (1998)

Frink, Sabine, Roeser, Siegfried, Alcala, Juan M., Covino, Elvira, Brandner, Wolfgang

We study the kinematics of T Tauri stars (TTS) located in the cores of the Chamaeleon clouds as well as far off these clouds. Our sample comprises 2 early type stars known to be related to Cha I, 6...

Star formation environments and the distribution of binary separations (1998)

Brandner, Wolfgang, Koehler, Rainer

We have carried out K-band speckle observations of a sample of 114 X-ray selected weak-line T Tauri stars in the nearby Scorpius-Centaurus OB association. We find that for binary T Tauri stars...

HIPPARCOS results for ROSAT-discovered young stars (1997)

Neuhaeuser, Ralph, Brandner, Wolfgang

Out of about 500 Lithium-rich ROSAT counterparts, which are presumed to be low-mass pre-main sequence stars, 21 stars have been observed by HIPPARCOS. We study their parallaxes, proper motions, and...

The Hourglass Nebulae of Sher 25 and SN 1987 A: Two of a Kind? (1997)

Brandner, Wolfgang, Chu, You-Hua, Eisenhauer, Frank, Grebel, Eva K., Points, Sean D.

We have performed a detailed study of the morphology and kinematics of the hourglass-shaped nebula around the blue supergiant Sher 25 in the galactic giant HII region NGC 3603. Near-infrared high...

Ring Nebula and Bipolar Outflows Associated with the B1.5 Supergiant Sher #25 in NGC 3603 (1996)

Brandner, Wolfgang, Grebel, Eva K., Chu, You-Hua, Weis, Kerstin

We have identified a ring-shaped emission-line nebula and a possible bipolar outflow centered on the B1.5 supergiant Sher #25 in the Galactic giant HII region NGC 3603 (distance 6 kpc). The clumpy...

Physical Properties of 90 AU to 250 AU Pre-Main-Sequence Binaries (1996)

Brandner, Wolfgang, Zinnecker, Hans

We have analyzed photometric and spectroscopic data of a sample of 14 spatially resolved pre-main-sequence binaries (separations 0.6" to 1.7") in the nearby (150 pc) low-mass star-forming regions of...

Simultaneous optical speckle masking and NIR adaptive optics imaging of the 126 mas Herbig Ae/Be binary star NX Puppis (1996)

Schöller, Markus, Brandner, Wolfgang, Lehmann, Thomas, Weigelt, Gerd, Zinnecker, Hans

We present simultaneous optical and near-infrared high angular resolution observations of the close Herbig Ae/Be binary star NX Pup which is associated with cometary globule~1. The reconstructed...

On the nature of the blue giants in NGC 330 (1995)

Grebel, Eva K., Roberts, Wm James, Brandner, Wolfgang

The young SMC cluster NGC 330 contains a number of blue stars that lie above the main-sequence turnoff found from our isochrone fitting and below the position of the blue supergiants. We used our...

Multiplicity among T Tauri stars in OB and T associations: Implications for binary star formation (1995)

Brandner, Wolfgang, Alcala, Juan M., Kunkel, Michael, Moneti, Andrea, Zinnecker, Hans

We present first results of a survey for companions among X-ray selected pre-main sequence stars, most of them being weak-line T Tauri stars (WTTS). These T Tauri stars have been identified in the...

The outburst of the T Tauri star EX Lupi in 1994 (1995)

Lehmann, Thomas, Reipurth, Bo, Brandner, Wolfgang

We have observed an outburst of the T Tauri star EX Lup in March 1994. We present both photometric (BVR) and spectroscopic (low and medium resolution) observations carried out during the decline...

Low-mass star formation in CG1: a diffraction limited search for pre-main sequence stars next to NX Puppis (1995)

Brandner, Wolfgang, Bouvier, Jerome, Grebel, Eva K., Tessier, Eric, De Winter, Dolf, Beuzit, Jean-Luc

Using adaptive optics at the ESO 3.6m telescope, we obtained diffraction limited JHK-images of the region around the Herbig AeBe star NX Pup. We clearly resolved the close companion (sep. 0.128") to...