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J/A+A/426/81        Kinematic analysis of the Minispiral      (Paumard+, 2004)

Kinematic and structural analysis of the Minispiral in the Galactic Center from BEAR spectro-imagery. Paumard T., Maillard J.-P., Morris M. <Astron. Astrophys. 426, 81 (2004)> =2004A&A...426...81P
ADC_Keywords: H II regions ; Infrared sources ; Space velocities Keywords: Galaxy: center - ISM: individual objects: Sgr A West - ISM: kinematics and dynamics - infrared: ISM - instrumentation: interferometers - line: profiles Description: We have obtained BEAR spectro-imaging data of the Galactic Center HII region "Sgr A West", also known as the "Minispiral", in the hydrogen Brackett γ line (2.166 microns). Through multi-component line fitting, we have decomposed this HII region into nine overlapping velocity structures, for which we have extracted the line flux and radial velocity maps. We have then fitted a set of Keplerian orbits onto the radial velocity map of the most extended structure (the "Northern Arm"), assuming that it was orbiting the central black hole candidate Sgr A*. This fit allows us to propose a three-dimensional kinematic model for this structure, which is hereby given as a set of FITS files. In this model, the central mass, its location in the field, and the distance to the Galactic Center are fixed: we use a mass of 3e6 solar masses and a distance of 8kpc; the pixel scale is 0.353 arcsec/pix, Sgr A* is considered to be located at pixel (59.2538, 38.9849) (IDL notation: (0, 0) is the center of the lower-left pixel, add 1 for FITS convention). Objects: ------------------------------------------ RA (2000) DE Designation(s) ------------------------------------------ 17 45 39.95 -29 00 28.2 Sgr A West ------------------------------------------ Note: The position given here is that of the radio source and supermassive black hole candidate Sgr A*, at the focus of the orbits in our model. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file 2880 82 *Three-dimensional velocity map in km/s 2880 82 *Error bars for in km/s 2880 28 *Line-of-sight distance in mas 2880 28 *Error bars for in mas
Note on Three-dimensional velocity map, a stack of three images (on the third axis of the FITS file) giving, in km/s, the velocity in each of the three dimensions: eastwards (V_alpha), northwards (V_delta), and outwards (V_radial). Note on Line-of-sight distance relative to the plane containing the central mass (Sgr A*), in equivalent milli-arcseconds on the sky. Positive for points of the structure further away from the observer than the central mass. Note on and The error bars are evaluated as follows: each fitting parameter is slightly moved within the range where moving it does not change Chi2 by more than 2 sigma. For each point of the field, we keep the highest and lowest values for each of the 4 variables we are interested in (LOS distance plus 3D velocity). The error bar is then (highest value-lowest value)/2.
Acknowledgements: Thibaut Paumard, paumard(at) References: Maillard, J. P., 1995, 3D-Spectroscopy with a Fourier Transform Spectrometer, in Tridimensional Optical Spectroscopic Methods in Astrophysics, ed. G. Comte & M. Marcelin, ASP Conf. Ser., 71, 316, 1995tosm.conf..316M Maillard, J. P. 2000, BEAR Imaging FTS: High Resolution Spectroscopy in Infrared Emission Lines, in Imaging the Universe in Three Dimensions, ed. W. van Breugel & J. Bland-Hawthorn, ASP Conf. Ser., 195, 185, 2000iutd.conf..185M
(End) Paumard [Max-Planck-Institut fuer extraterrestrische Physik] 09-Jul-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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