Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/0502129)
· On-line Data
· References in the article
· Citations to the Article (517) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (19)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month
Authors:
Eisenhauer, F.; Genzel, R.; Alexander, T.; Abuter, R.; Paumard, T.; Ott, T.; Gilbert, A.; Gillessen, S.; Horrobin, M.; Trippe, S.; Bonnet, H.; Dumas, C.; Hubin, N.; Kaufer, A.; Kissler-Patig, M.; Monnet, G.; Ströbele, S.; Szeifert, T.; Eckart, A.; Schödel, R.; Zucker, S.
Affiliation:
AA(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AB(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany; Department of Physics, University of California, Berkeley, CA 94720.), AC(Center for Astrophysics, Weizmann Institute of Science, Rehovot, Israel; Incumbent of the William Z. and Eda Bess Novick career development chair.), AD(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AE(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AF(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AG(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AH(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AI(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AJ(Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany), AK(European Southern Observatory (ESO), Garching bei München, Germany), AL(European Southern Observatory (ESO), Garching bei München, Germany), AM(European Southern Observatory (ESO), Garching bei München, Germany), AN(European Southern Observatory (ESO), Garching bei München, Germany), AO(European Southern Observatory (ESO), Garching bei München, Germany), AP(European Southern Observatory (ESO), Garching bei München, Germany), AQ(European Southern Observatory (ESO), Garching bei München, Germany), AR(European Southern Observatory (ESO), Garching bei München, Germany), AS(Physikalisches Institut der Universität Köln, Germany), AT(Physikalisches Institut der Universität Köln, Germany), AU(Center for Astrophysics, Weizmann Institute of Science, Rehovot, Israel.)
Publication:
The Astrophysical Journal, Volume 628, Issue 1, pp. 246-259. (ApJ Homepage)
Publication Date:
07/2005
Origin:
UCP
Astronomy Keywords:
Black Hole Physics, Galaxy: Center, Galaxy: Structure, Infrared: Stars, Techniques: Spectroscopic
DOI:
10.1086/430667
Bibliographic Code:
2005ApJ...628..246E

Abstract

We report on 75 mas resolution, near-IR imaging spectroscopy within the central 30 lt-days of the Galactic center, taken with the new adaptive optics-assisted integral-field spectrometer SINFONI on the ESO VLT. To a limiting magnitude of K~16, 9 of 10 stars in the central 0.4", and 13 of 17 stars out to 0.7" from the central black hole have spectral properties of B0-B9 main-sequence stars. Based on the 2.1127 mum He I line width, all brighter early-type stars have normal rotation velocities, similar to solar neighborhood stars. We combine the new radial velocities with SHARP/NACO astrometry to derive improved three-dimensional stellar orbits for six of these ``S stars'' in the central 0.5". Their orientations in space appear random. Their orbital planes are not co-aligned with those of the two disks of massive young stars 1"-10" from Sgr A*. We can thus exclude the hypothesis that the S stars as a group inhabit the inner regions of these disks. They also cannot have been located/formed in these disks and then migrated inward within their planes. From the combination of their normal rotation and random orbital orientations, we conclude that the S stars were most likely brought into the central light-month by strong individual scattering events. The updated estimate of distance to the Galactic center from the S2 orbit fit is R0=7.62+/-0.32 kpc, resulting in a central mass value of (3.61+/-0.32)×106 Msolar. We happened to catch two smaller flaring events from Sgr A* during our spectral observations. The 1.7-2.45 mum spectral energy distributions of these flares are fit by a featureless, ``red'' power law of spectral index alpha'=-4+/-1 (Snu~nualpha'). The observed spectral slope is in good agreement with synchrotron models in which the infrared emission comes from accelerated, nonthermal, high-energy electrons in a radiatively inefficient accretion flow in the central R~10RS region.

Based on observations obtained at the Very Large Telescope of the European Southern Observatory, Chile.


Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints