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General Relativistic effects and the NIR variability of Sgr A* II: A systematic approach to temporal asymmetry
- Source :
- A&A 688, L12 (2024)
- Publication Year :
- 2024
-
Abstract
- A systematic study, based on the third-moment structure function, of Sgr A*'s variability finds an exponential rise time $\tau_{1,\rm{obs}}=14.8^{+0.4}_{-1.5}~\mathrm{minutes}$ and decay time $\tau_{2,\rm{obs}}=13.1^{+1.3}_{-1.4}~\mathrm{minutes}$. This symmetry of the flux-density variability is consistent with earlier work, and we interpret it as caused by the dominance of Doppler boosting, as opposed to gravitational lensing, in Sgr~A*'s light curve. A relativistic, semi-physical model of Sgr~A* confirms an inclination angle $i<45$ degrees. The model also shows that the emission of the intrinsic radiative process can have some asymmetry even though the observed emission does not. The third-moment structure function, which is a measure of the skewness of the light-curve increments, may be a useful summary statistic in other contexts of astronomy because it senses only temporal asymmetry, i.e., it averages to zero for any temporally symmetric signal.<br />Comment: Accepted for publication in A&A letters
Details
- Database :
- arXiv
- Journal :
- A&A 688, L12 (2024)
- Publication Type :
- Report
- Accession number :
- edsarx.2407.07091
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1051/0004-6361/202451146