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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

References

Bremer, M., Witzel, G., Eckart, A., et al. 2011, A&A 532, A26Google Scholar
Diolaiti, E., Bendinelli, O., Bonaccini, D., et al. 2000, in Presented at the Society of Photo-Optical Instrumentation Engineers (SPIE) Conference, Vol. 4007, Proc. SPIE Vol. 4007, p. 879-888, Adaptive Optical Systems Technology, Peter L. Wizinowich; Ed., ed. P.L. Wizinowich, 879–888Google Scholar
Do, T., Ghez, A. M., Morris, M. R., et al. 2009, ApJ 691, 1021CrossRefGoogle Scholar
Dodds-Eden, K., Gillessen, S., Fritz, T. K., et al. 2011, ApJ 728, 37Google Scholar
Eckart, A., García-Marín, M., Vogel, S. N., et al. 2012, A&A 537, A52Google Scholar
Eckart, A., Schödel, R., Meyer, L., et al. 2006, A&A 455, 1Google Scholar
Eisenhauer, F., Genzel, R., Alexander, T., et al. 2005, ApJ 628, 246Google Scholar
Genzel, R., Eisenhauer, F., & Gillessen, S. 2010, Reviews of Modern Physics, 82, 3121Google Scholar
Genzel, R., Schödel, R., Ott, T., et al. 2003, Nature 425, 934Google Scholar
Ghez, A. M., Hornstein, S.D., Lu, J. R., et al. 2005, ApJ 635, 1087Google Scholar
Ghez, A. M., Salim, S., Weinberg, N. N., et al. 2008, ApJ 689, 1044Google Scholar
Gillessen, S., Eisenhauer, F., Quataert, E., et al. 2006, ApJ Lett. 640, L163Google Scholar
Heil, L. M., Vaughan, S., & Uttley, P. 2011, MNRAS 411, L66CrossRefGoogle Scholar
Hornstein, S. D., Matthews, K., Ghez, A. M., et al. 2007, ApJ 667, 900Google Scholar
Krabbe, A., Iserlohe, C., Larkin, J. E., et al. 2006, ApJ Lett. 642, L145Google Scholar
Meyer, L., Do, T., Ghez, A., et al. 2009, ApJ Lett. 694, L87Google Scholar
Meyer, L., Schödel, R., Eckart, A., et al. 2006, A&A 458, L25Google Scholar
Morris, M. R., Meyer, L., & Ghez, A. M. 2012, Research in Astronomy and Astrophysics, 12, 995Google Scholar
Schödel, R., Morris, M. R., Muzic, K., et al. 2011, A&A 532, A83Google Scholar
Schödel, R., Najarro, F., Muzic, K., & Eckart, A. 2010, A&A 511, A18Google Scholar
Timmer, J. & Koenig, M. 1995, A&A 300, 707Google Scholar
Trap, G., Goldwurm, A., Dodds-Eden, K., et al. 2011, A&A 528, A140Google Scholar
Uttley, P. & McHardy, I. M. 2001, MNRAS 323, L26CrossRefGoogle Scholar
Uttley, P., McHardy, I. M., & Vaughan, S. 2005, MNRAS 359, 345Google Scholar
Witzel, G., Eckart, A., Bremer, M., et al. 2012, ApJS 203, 18CrossRefGoogle Scholar