Dynamic energy/power spectra from X-ray spectra and light curves
Abstract
The key data product of an X-ray observation is an events table with information of calibrated position, energy, and arrival time for each individual X-ray photon. Many X-ray sources are variable and clues for origins for variations can be found in spectral changes along with light curve variations. This is commonly done by extracting spectra from certain episodes of variability such as low-states/high-states. I present a systematic approach of a dynamic X-ray spectrum, a 3-dimensional representation of wavelength/energy, time, and intensity. It is constructed from a series of spectra extracted from adjacent short time intervals, displayed as wavelength (or energy) versus time and a colour code for intensity. The same concept can be used for dynamic power spectra, displaying the evolution of periodic oscillations in an X-ray light curve. Dynamic energy/power spectra constructed from XMM-Newton and Chandra data have revealed some surprises such as short-lived emission lines during a flare, softening owed to changes in the absorption column of OI, or transient short-period oscillations in various supersoft sources. Some examples are shown to illustrate the diagnostic power of these diagrams.
- Publication:
-
Exploring the Hot and Energetic Universe: The first scientific conference dedicated to the Athena X-ray observatory
- Pub Date:
- September 2015
- Bibcode:
- 2015eheu.conf...54N