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Low-Intensity States in the Neutron Star X-ray Binary Aql X-1

Dipankar Maitra·Charles D. Bailyn
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Abstract

Aql X-1 was observed in a Low Intensity State (LIS), a state that is usually characterized by high optical but low X-ray flux. Our daily monitoring of the source using the 1.3m telescope in Cerro Tololo Inter-America Observatory operated by the Small and Moderate Aperture Research Telescope System (SMARTS) was used to trigger a series of target-of-opportunity (ToO) observations of the source using the Rossi X-ray Timing Explorer satellite (RXTE). The X-ray colors and temporal variability studies suggest that the source was in a powerlaw dominated state featuring high rms variability in the lightcurve and dominance of hard photons during this LIS. The ToO observations were continued until the source made a transition to the canonical thermal dominated or high/soft state.

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Dipankar Maitra, Charles D. Bailyn. 2005-10-11. Low-Intensity States in the Neutron Star X-ray Binary Aql X-1. https://arxiv.org/abs/astro-ph/0510329

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