Simultaneous Monitoring of X-Ray and Radio Variability in Sagittarius A*
| Autor: | Geoffrey C. Bower, Nathalie Degenaar, Daryl Haggard, Daniel M. Capellupo, Heino Falcke, Sera Markoff, Nanda Rea, Nicolas Choux, Frederick K. Baganoff, Craig O. Heinke, Jason Dexter, P. Chris Fragile, Bill Cotton, Farhad Yusef-Zadeh, Casey J. Law, Gabriele Ponti, J. Neilsen |
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| Přispěvatelé: | High Energy Astrophys. & Astropart. Phys (API, FNWI) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Astronomy
Lag Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Time lag Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences law.invention law 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Short duration High Energy Astrophysical Phenomena (astro-ph.HE) Physics Sagittarius A 010308 nuclear & particles physics Astronomy and Astrophysics Long wavelength Wavelength Space and Planetary Science ComputingMethodologies_DOCUMENTANDTEXTPROCESSING Astrophysics - High Energy Astrophysical Phenomena Statistical evidence Flare |
| Zdroj: | The Astrophysical Journal, 845, 1-13 Astrophysical Journal, 845(1):35. IOP Publishing Ltd. The Astrophysical Journal, 845, 1, pp. 1-13 |
| ISSN: | 0004-637X |
| Popis: | Monitoring of Sagittarius A* from X-ray to radio wavelengths has revealed structured variability --- including X-ray flares --- but it is challenging to establish correlations between them. Most studies have focused on variability in the X-ray and infrared, where variations are often simultaneous, and because long time series at sub-millimeter and radio wavelengths are limited. Previous work on sub-mm and radio variability hints at a lag between X-ray flares and their candidate sub-millimeter or radio counterparts, with the long wavelength data lagging the X-ray. However, there is only one published time lag between an X-ray flare and a possible radio counterpart. Here we report 9 contemporaneous X-ray and radio observations of Sgr A*. We detect significant radio variability peaking $\gtrsim$176 minutes after the brightest X-ray flare ever detected from Sgr A*. We also report other potentially associated X-ray and radio variability, with the radio peaks appearing $\lesssim$80 minutes after these weaker X-ray flares. Taken at face value, these results suggest that stronger X-ray flares lead to longer time lags in the radio. However, we also test the possibility that the variability at X-ray and radio wavelengths is not temporally correlated. We cross-correlate data from mismatched X-ray and radio epochs and obtain comparable correlations to the matched data. Hence, we find no overall statistical evidence that X-ray flares and radio variability are correlated, underscoring a need for more simultaneous, long duration X-ray--radio monitoring of Sgr A*. Comment: Accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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