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Near infrared variability of Sgr A* - spectral index measurements

Published online by Cambridge University Press:  22 May 2014

G. Witzel ,
M. Morris ,
A. Ghez ,
L. Meyer ,
E. Becklin ,
K. Matthews ,
J. R. Lu ,
T. Do  and
R. Campbell
G. Witzel
Affiliation:
Dep. of Physics and Astronomy, University of California Los Angeles (UCLA), 465 Portola Plaza, Los Angeles, CA 90095, USA email: witzel@astro.ucla.edu
M. Morris
Affiliation:
Dep. of Physics and Astronomy, University of California Los Angeles (UCLA), 465 Portola Plaza, Los Angeles, CA 90095, USA email: witzel@astro.ucla.edu
A. Ghez
Affiliation:
Dep. of Physics and Astronomy, University of California Los Angeles (UCLA), 465 Portola Plaza, Los Angeles, CA 90095, USA email: witzel@astro.ucla.edu
L. Meyer
Affiliation:
Dep. of Physics and Astronomy, University of California Los Angeles (UCLA), 465 Portola Plaza, Los Angeles, CA 90095, USA email: witzel@astro.ucla.edu
E. Becklin
Affiliation:
Dep. of Physics and Astronomy, University of California Los Angeles (UCLA), 465 Portola Plaza, Los Angeles, CA 90095, USA email: witzel@astro.ucla.edu
K. Matthews
Affiliation:
Caltech, Pasadena, USA
J. R. Lu
Affiliation:
Institute for Astronomy, University of Hawaii, USA
T. Do
Affiliation:
Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Canada
R. Campbell
Affiliation:
Keck Observatory, Kamuela, Hawaii, USA
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Abstract

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We discuss observations of Sagittarius A* with NACO@VLT in K-band and recent synchronous observations with NIRC2@Keck II and OSIRIS@Keck I in L′-band and H-band, respectively. The variability of Sagittarius A* in the near infrared is a continuous one-state process that can be described by a pure red-noise process having a timescale of a few hours. We describe this process and its properties in detail. Our newest observations with the Keck telescopes represent the first truly synchronous high cadence data set to test for time variability of the spectral index within the near infrared. We discovered a time-variable spectral index that might be interpreted as a time lag of the L′-band with respect to the H-band.

Keywords

Galaxy: center — black hole physics — radiation mechanisms: general — methods: statistical
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 9 , Symposium S303: The Galactic Center: Feeding and Feedback in a Normal Galactic Nucleus , October 2013 , pp. 274 - 282
Copyright
Copyright © International Astronomical Union 2014 

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