Milky Way nuclear star cluster extinction map Virtual Observatory Resource

Authors
  1. Schoedel R.
  2. Feldmeier A.
  3. Kunneriath D.
  4. Stolovy S.
  5. Neumauer N.
  6. Published by
    CDS
Abstract

Although the Milky Way Nuclear Star Cluster (MWNSC) was discovered more than four decades ago, several of its key properties have not been determined unambiguously up to now because of the strong and spatially highly variable interstellar extinction toward the Galactic centre. In this paper we aim at determining the shape, size, and luminosity/mass of the MWNSC.In order to investigate the properties of the MWNSC, we use Spitzer/IRAC images at 3.6 and 4.5{mu}m, where interstellar extinction is at a minimum but the overall emission is still dominated by stars. We correct the 4.5{mu}m image for PAH emission with the help of the IRAC 8.0{mu}m map and for extinction with the help of a [3.6-4.5] colour map. Finally, we investigate the symmetry of the nuclear cluster and fit it with Sersic, Moffat, and King models. We present an extinction map for the central ~300x200pc^2^ of the Milky Way, as well as a PAH-emission and extinction corrected image of the stellar emission, with a resolution of about 0.20pc. We find that the MWNSC appears in projection intrinsically point-symmetric, that it is significantly flattened, with its major axis aligned along the Galactic Plane, and that it is centred on the black hole, Sagittarius A*. Its density follows the well known approximate {rho}{prop.to}r^-2^-law at distances of a few parsecs from Sagittarius A*, but becomes as steep as about {rho}{prop.to}r^-3^ at projected radii around 5pc. We derive a half light radius of 4.2+/-0.4pc, a total luminosity of L_MWNSC,4.5{mu}m_=4.1+/-0.4x10^7^L_{sun}_, and a mass of M_MWNSC_=2.1+/-0.4x10^7^M_{sun}_. The overall properties of the MWNSC agree well with the ones of its extragalactic counterparts, which underlines its role as a template for these objects. Its flattening agrees well with its previously established rotation parallel to Galactic rotation and suggests that it has formed by accretion of material that fell in preferentially along the Galactic Plane. Our findings support the in situ growth scenario for nuclear clusters and emphasize the need to increase the complexity of theoretical models for their formation and for the interaction between their stars and the central black hole in order to include rotation, axisymmetry, and growth in recurrent episodes.

Keywords
  1. extinction
  2. milky-way-galaxy
  3. infrared-sources
Bibliographic source Bibcode
2014A&A...566A..47S
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/566/A47
IVOA Identifier IVOID
ivo://CDS.VizieR/J/A+A/566/A47
Document Object Identifer DOI
doi:10.26093/cds/vizier.35660047

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History

2014-06-11T06:44:03Z
Resource record created
2014-06-11T06:44:03Z
Created
2018-01-04T15:07:02Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr