T. Alexander

Publication List Details

Period

1883 - 2009

Number

66

Co-Authors

An Extremely Top-Heavy IMF in the Galactic Center Stellar Disks (2009)

Bartko, H., Martins, F., Trippe, S., Fritz, T. K., Genzel, R., Ott, T., ...

We present new observations of the nuclear star cluster in the central parsec of the Galaxy with the adaptive optics assisted, integral field spectrograph SINFONI on the ESO/VLT. Our work allows the...

The Galactic Center: A Laboratory for Fundamental Astrophysics and Galactic Nuclei (2009)

Ghez, A., Morris, M., Lu, J., Weinberg, N., Matthews, K., Alexander, T., ...

As the closest example of a galactic nucleus, the Galactic center presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environs. Detailed studies of stellar...

Evidence for Warped Disks of Young Stars in the Galactic Center (2008)

Bartko, H., Martins, F., Fritz, T. K., Genzel, R., Levin, Y., Perets, H. B., ...

The central parsec around the super-massive black hole in the Galactic Center hosts more than 100 young and massive stars. Outside the central cusp (R~1") the majority of these O and Wolf-Rayet (WR)...

Monitoring stellar orbits around the Massive Black Hole in the Galactic Center (2008)

Gillessen, S., Eisenhauer, F., Trippe, S., Alexander, T., Genzel, R., Martins, F., ...

We present the results of 16 years of monitoring stellar orbits around the massive black hole in center of the Milky Way using high resolution NIR techniques. This work refines our previous analysis...

Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy (2007)

Maness, H., Martins, F., Trippe, S., Genzel, R., Graham, J. R., Sheehy, C., ...

We classify 329 late-type giants within 1 parsec of Sgr A*, using the adaptive optics integral field spectrometer SINFONI on the VLT. These observations represent the deepest spectroscopic data set...

The structure of the nuclear stellar cluster of the Milky Way (2007)

Schoedel, R., Eckart, A., Alexander, T., Merritt, D., Genzel, R., Sternberg, A., ...

We present high-resolution seeing limited and AO NIR imaging observations of the stellar cluster within about one parsec of Sgr A*, the massive black hole at the centre of the Milky Way. Stellar...

The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation (2006)

Paumard, T., Genzel, R., Martins, F., Nayakshin, S., Beloborodov, A. M., Levin, Y., ...

We report the definite spectroscopic identification of 41 OB supergiants, giants and main sequence stars in the central parsec of the Galaxy. Detection of their absorption lines have become possible...

Den fremmede kvinne i Ordspråkene 1-9 (2006)

T. Alexander

Salomos Ordspråk (Proverbia) har 31 kapitler, og består av to deler; den ene begynner med kapittel 10, og står som ordtak, mens kapitlene 1-9 er en generell parenese om å akte på visdommen....

SINFONI in the Galactic Center: young stars and IR flares in the central light month (2005)

Eisenhauer, F., Genzel, R., Alexander, T., Abuter, R., Paumard, T., Ott, T., ...

We report 75 milli-arcsec resolution, near-IR imaging spectroscopy within the central 30 light days of the Galactic Center [...]. To a limiting magnitude of K~16, 9 of 10 stars in the central 0.4...

Ultraluminous X-Ray Sources as Intermediate-Mass Black Holes Fed by Tidally Captured Stars (2004)

Hopman, C., Portegies Zwart, S.F., Alexander, T.

The nature of ultraluminous X-ray (ULX) sources is presently unknown. A possible explanation is that they are accreting intermediate-mass black holes (IBHs) that are fed by Roche lobe overflow from a...

A Geometric Determination of the Distance to the Galactic Center (2003)

Eisenhauer, F., Schoedel, R., Genzel, R., Ott, T., Tecza, M., Abuter, R., ...

We report new astrometric and spectroscopic observations of the star S2 orbiting the massive black hole in the Galactic Center, which were taken at the ESO VLT with the adaptive optics assisted,...

Stellar dynamics in the central arcsecond of our galaxy (2003)

Schoedel, R., Genzel, R., Ott, T., Eckart, A., Mouawad, N., Alexander, T.

We present proper motions for $>$40 stars at projected distances $\leq1.2''$ from Sagittarius A* (Sgr A*). We find evidence on a $\geq2\sigma$ level for radial anisotropy of the cluster of stars...

The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center (2003)

Genzel, R., Schoedel, R., Ott, T., Eisenhauer, F., Hofmann, R., Lehnert, M., ...

We analyze deep near-IR adaptive optics imaging as well as new proper motion data of the nuclear star cluster of the Milky Way. The surface density distribution of faint stars peaks within 0.2" of...

Inward Bound: Studying the Galactic Centre with NAOS/CONICA (2003)

Ott, T., Schoedel, R., Genzel, R., Eckart, A., Lacombe, F., Rouan, D., ...

We report on the first results obtained using adaptive optics measurements of the Galactic Centre done with NAOS/CONICA.

The stellar cusp around the supermassive black hole in the galactic center (2003)

Genzel, R., Schödel, R., Ott, T., Eisenhauer, F., Hofmann, R., Lehnert, M., ...

We analyze deep near-IR adaptive optics imaging (taken with NAOS/CONICA on the Very Large Telescope at the European Southern Observatory, Chile), as well as new proper-motion data of the nuclear star...

Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way (2002)

Schodel, R., Ott, T., Genzel, R., Hofmann, R., Lehnert, M., Eckart, A., ...

Measurements of stellar velocities and variable X-ray emission near the centre of the Milky Way have provided the strongest evidence so far that the dark mass concentrations seen in many galactic...

A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way (2002)

Schödel, R., Ott, T., Genzel, R., Hofmann, R., Lehnert, M., Eckart, A., ...

Many galaxies are thought to have supermassive black holes at their centres(1)-more than a million times the mass of the Sun. Measurements of stellar velocities(2-7) and the discovery of variable...

A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way (2002)

Schödel, R., Ott, T., Genzel, R., Hofmann, R., Lehnert, M., Eckart, A., ...

Many galaxies are thought to have supermassive black holes at their centres(1)-more than a million times the mass of the Sun. Measurements of stellar velocities(2-7) and the discovery of variable...

ISO-SWS spectroscopy of NGC 1068 (2000)

Lutz, D., Sturm, E., Genzel, R., Moorwood, A. F. M., Alexander, T., Netzer, H., ...

We present ISO-SWS spectroscopy of NGC 1068 for the wavelength range 2.4 to 45um, detecting a total of 36 emission lines. Most of the observed transitions are fine structure and recombination lines...

A search for broad infrared recombination lines in NGC 1068 (1999)

Lutz, D., Genzel, R., Sturm, E., Tacconi, L., Wieprecht, E., Alexander, T., ...

We report infrared spectroscopy of the prototypical Seyfert 2 galaxy NGC 1068, aiming at detection of broad components of hydrogen recombination lines that originate in the obscured broad-line...

Development and Evaluation of Novel Implantable Nanosensors for Real-Time Monitoring of Individual Cells and Cellular Signaling (1998)

Cullum, B. M., Ostrand-Rosenberg, S., Alexander, T.

The goal of this project was to develop and demonstrate the potential of a versatile class of nano-biosensors capable of being implanted within individual living cells for the direct conversion of...

Infrared spectroscopy of NGC 4151: ISO observations and NLR line profiles (1998)

Sturm, E., Alexander, T., Lutz, D., Sternberg, A., Netzer, H., Genzel, R.

We present ISO-SWS and ISOPHOT-S spectroscopy of the Seyfert galaxy NGC 4151. We detect a total of 17 fine structure emission lines emitted by a wide range of low- and high-excitation ions, two...

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XIV. Intensive Optical Spectrophotometric Observations of NGC 7469 (1998)

Collier, S.J., Horne, Keith, Kaspi, S., Netzer, H., Peterson, B.M., Wanders, I., ...

We present results of an intensive 2 month campaign of ground-based spectrophotometric monitoring of the Seyfert 1 galaxy NGC 7469, with a temporal resolution [approximately less than]1 day. The...

STEPS TOWARD DETERMINATION OF THE SIZE AND STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. XI. INTENSIVE MONITORING OF THE ULTRAVIOLET SPECTRUM OF NGC 7469 (1997)

Wanders, I., Peterson, B.M., Alloin, D., Ayres, T.R., Clavel, J., Crenshaw, D.M., ...

From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored the Seyfert 1 galaxy NGC 7469 continuously in an attempt to measure time delays between the continuum and emission-line...

Two Widely-Different Architectural Approaches to Computer Image Generation (1991)

Park, H.W., Eo, K.S., Kim, D.L., Choi, B.K., Kim, Y., Alexander, T.

Among several systems from the UWGSP (University of Washington Graphics System Processor) series, two recent architectures were designed for imaging and graphics, One of them, UWGSP3, has already...

A High Performance Parallel Computing System for Imaging and Graphics (1991)

Park, H.W., Alexander, T., Moon, S.H., Kim, Y.

UWGSP4 (University of Washington Graphics System Processor) consists of four parts: a parallel vector processor, a shared-memory system, an interconnection network, and a graphics subsystem. The...

Suppressor cell defect in SLE: relationship to native DNA binding.

Krakauer, R S, Clough, J D, Alexander, T, Sundeen, J, Sauder, D N

Recent evidence suggests the presence of a suppressor T cell defect in systemic lupus erythematosus. We confirm the presence of such a defect and find a strong quantitative correlation between the...

Mid term outcome and quality of life after aortic valve replacement in elderly people: mechanical versus stentless biological valves

Florath, I, Albert, A, Rosendahl, U, Alexander, T, Ennker, I C, Ennker, J

Objective: To assess the benefit for patients older than 65 years of aortic valve replacement with stentless biological heart valves in comparison with mechanical valves.