Modeling mm- to X-ray flare emission from sagittarius A

A. Eckart, F. K. Baganoff, M. R. Morris, D. Kunneriath, M. Zamaninasab, G. Witzel, R. Schödel, M. García-Marín, L. Meyer, G. C. Bower, D. Marrone, M. W. Bautz, William Nielsen Brandt, G. P. Garmire, G. R. Ricker, C. Straubmeier, D. A. Roberts, K. Muzic, J. Mauerhan, A. Zensus

Research output: Contribution to journalArticle

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Abstract

Context. We report on new modeling results based on the mm- to X-ray emission of the SgrA* counterpart associated with the massive ∼4×106 Mȯ black hole at the Galactic Center.Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. Our modeling is based on simultaneous observations carried out on 07 July, 2004, using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope*and the ACIS-I instrument aboard the Chandra X-ray Observatory as well as the Submillimeter Array SMA**on Mauna Kea, Hawaii, and the Very Large Array***in New Mexico. Results. The observations revealed several flare events in all wavelength domains. Here we show that the flare emission can be described with a combination of a synchrotron self-Compton (SSC) model followed by an adiabatic expansion of the source components. The SSC emission at NIR and X-ray wavelengths involves up-scattered sub-millimeter photons from a compact source component. At the start of the flare, spectra of these components peak at frequencies between several 100 GHz and 2 THz. The adiabatic expansion then accounts for the variable emission observed at sub-mm/mm wavelengths. The derived physical quantities that describe the flare emission give a blob expansion speed of vexp ∼ 0.005 c, magnetic field of B around 60 G or less and spectral indices of α = 0.8 to 1.4, corresponding to a particle spectral index p ∼2.6 to 3.8. Conclusions. A combined SSC and adiabatic expansion model can fully account for the observed flare flux densities and delay times covering the spectral range from the X-ray to the mm-radio domain. The derived model parameters suggest that the adiabatic expansion takes place in source components that have a bulk motion larger than vexp or the expanding material contributes to a corona or disk, confined to the immediate surroundings of SgrA*.

Original languageEnglish (US)
Pages (from-to)935-946
Number of pages12
JournalAstronomy and Astrophysics
Volume500
Issue number3
DOIs
StatePublished - Jun 1 2009

Fingerprint

flares
expansion
modeling
synchrotrons
x rays
wavelength
observatory
wavelengths
spectral mixture analysis
Very Large Array (VLA)
European Southern Observatory
adaptive optics
coronas
corona
observatories
coverings
time lag
flux density
telescopes
radio

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Eckart, A., Baganoff, F. K., Morris, M. R., Kunneriath, D., Zamaninasab, M., Witzel, G., ... Zensus, A. (2009). Modeling mm- to X-ray flare emission from sagittarius A. Astronomy and Astrophysics, 500(3), 935-946. https://doi.org/10.1051/0004-6361/200811354
Eckart, A. ; Baganoff, F. K. ; Morris, M. R. ; Kunneriath, D. ; Zamaninasab, M. ; Witzel, G. ; Schödel, R. ; García-Marín, M. ; Meyer, L. ; Bower, G. C. ; Marrone, D. ; Bautz, M. W. ; Brandt, William Nielsen ; Garmire, G. P. ; Ricker, G. R. ; Straubmeier, C. ; Roberts, D. A. ; Muzic, K. ; Mauerhan, J. ; Zensus, A. / Modeling mm- to X-ray flare emission from sagittarius A. In: Astronomy and Astrophysics. 2009 ; Vol. 500, No. 3. pp. 935-946.
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abstract = "Context. We report on new modeling results based on the mm- to X-ray emission of the SgrA* counterpart associated with the massive ∼4×106 Mȯ black hole at the Galactic Center.Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. Our modeling is based on simultaneous observations carried out on 07 July, 2004, using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope*and the ACIS-I instrument aboard the Chandra X-ray Observatory as well as the Submillimeter Array SMA**on Mauna Kea, Hawaii, and the Very Large Array***in New Mexico. Results. The observations revealed several flare events in all wavelength domains. Here we show that the flare emission can be described with a combination of a synchrotron self-Compton (SSC) model followed by an adiabatic expansion of the source components. The SSC emission at NIR and X-ray wavelengths involves up-scattered sub-millimeter photons from a compact source component. At the start of the flare, spectra of these components peak at frequencies between several 100 GHz and 2 THz. The adiabatic expansion then accounts for the variable emission observed at sub-mm/mm wavelengths. The derived physical quantities that describe the flare emission give a blob expansion speed of vexp ∼ 0.005 c, magnetic field of B around 60 G or less and spectral indices of α = 0.8 to 1.4, corresponding to a particle spectral index p ∼2.6 to 3.8. Conclusions. A combined SSC and adiabatic expansion model can fully account for the observed flare flux densities and delay times covering the spectral range from the X-ray to the mm-radio domain. The derived model parameters suggest that the adiabatic expansion takes place in source components that have a bulk motion larger than vexp or the expanding material contributes to a corona or disk, confined to the immediate surroundings of SgrA*.",
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Eckart, A, Baganoff, FK, Morris, MR, Kunneriath, D, Zamaninasab, M, Witzel, G, Schödel, R, García-Marín, M, Meyer, L, Bower, GC, Marrone, D, Bautz, MW, Brandt, WN, Garmire, GP, Ricker, GR, Straubmeier, C, Roberts, DA, Muzic, K, Mauerhan, J & Zensus, A 2009, 'Modeling mm- to X-ray flare emission from sagittarius A', Astronomy and Astrophysics, vol. 500, no. 3, pp. 935-946. https://doi.org/10.1051/0004-6361/200811354

Modeling mm- to X-ray flare emission from sagittarius A. / Eckart, A.; Baganoff, F. K.; Morris, M. R.; Kunneriath, D.; Zamaninasab, M.; Witzel, G.; Schödel, R.; García-Marín, M.; Meyer, L.; Bower, G. C.; Marrone, D.; Bautz, M. W.; Brandt, William Nielsen; Garmire, G. P.; Ricker, G. R.; Straubmeier, C.; Roberts, D. A.; Muzic, K.; Mauerhan, J.; Zensus, A.

In: Astronomy and Astrophysics, Vol. 500, No. 3, 01.06.2009, p. 935-946.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Modeling mm- to X-ray flare emission from sagittarius A

AU - Eckart, A.

AU - Baganoff, F. K.

AU - Morris, M. R.

AU - Kunneriath, D.

AU - Zamaninasab, M.

AU - Witzel, G.

AU - Schödel, R.

AU - García-Marín, M.

AU - Meyer, L.

AU - Bower, G. C.

AU - Marrone, D.

AU - Bautz, M. W.

AU - Brandt, William Nielsen

AU - Garmire, G. P.

AU - Ricker, G. R.

AU - Straubmeier, C.

AU - Roberts, D. A.

AU - Muzic, K.

AU - Mauerhan, J.

AU - Zensus, A.

PY - 2009/6/1

Y1 - 2009/6/1

N2 - Context. We report on new modeling results based on the mm- to X-ray emission of the SgrA* counterpart associated with the massive ∼4×106 Mȯ black hole at the Galactic Center.Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. Our modeling is based on simultaneous observations carried out on 07 July, 2004, using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope*and the ACIS-I instrument aboard the Chandra X-ray Observatory as well as the Submillimeter Array SMA**on Mauna Kea, Hawaii, and the Very Large Array***in New Mexico. Results. The observations revealed several flare events in all wavelength domains. Here we show that the flare emission can be described with a combination of a synchrotron self-Compton (SSC) model followed by an adiabatic expansion of the source components. The SSC emission at NIR and X-ray wavelengths involves up-scattered sub-millimeter photons from a compact source component. At the start of the flare, spectra of these components peak at frequencies between several 100 GHz and 2 THz. The adiabatic expansion then accounts for the variable emission observed at sub-mm/mm wavelengths. The derived physical quantities that describe the flare emission give a blob expansion speed of vexp ∼ 0.005 c, magnetic field of B around 60 G or less and spectral indices of α = 0.8 to 1.4, corresponding to a particle spectral index p ∼2.6 to 3.8. Conclusions. A combined SSC and adiabatic expansion model can fully account for the observed flare flux densities and delay times covering the spectral range from the X-ray to the mm-radio domain. The derived model parameters suggest that the adiabatic expansion takes place in source components that have a bulk motion larger than vexp or the expanding material contributes to a corona or disk, confined to the immediate surroundings of SgrA*.

AB - Context. We report on new modeling results based on the mm- to X-ray emission of the SgrA* counterpart associated with the massive ∼4×106 Mȯ black hole at the Galactic Center.Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. Our modeling is based on simultaneous observations carried out on 07 July, 2004, using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope*and the ACIS-I instrument aboard the Chandra X-ray Observatory as well as the Submillimeter Array SMA**on Mauna Kea, Hawaii, and the Very Large Array***in New Mexico. Results. The observations revealed several flare events in all wavelength domains. Here we show that the flare emission can be described with a combination of a synchrotron self-Compton (SSC) model followed by an adiabatic expansion of the source components. The SSC emission at NIR and X-ray wavelengths involves up-scattered sub-millimeter photons from a compact source component. At the start of the flare, spectra of these components peak at frequencies between several 100 GHz and 2 THz. The adiabatic expansion then accounts for the variable emission observed at sub-mm/mm wavelengths. The derived physical quantities that describe the flare emission give a blob expansion speed of vexp ∼ 0.005 c, magnetic field of B around 60 G or less and spectral indices of α = 0.8 to 1.4, corresponding to a particle spectral index p ∼2.6 to 3.8. Conclusions. A combined SSC and adiabatic expansion model can fully account for the observed flare flux densities and delay times covering the spectral range from the X-ray to the mm-radio domain. The derived model parameters suggest that the adiabatic expansion takes place in source components that have a bulk motion larger than vexp or the expanding material contributes to a corona or disk, confined to the immediate surroundings of SgrA*.

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Eckart A, Baganoff FK, Morris MR, Kunneriath D, Zamaninasab M, Witzel G et al. Modeling mm- to X-ray flare emission from sagittarius A. Astronomy and Astrophysics. 2009 Jun 1;500(3):935-946. https://doi.org/10.1051/0004-6361/200811354