Proposal Details - 1020008
Hard X-ray spectroscopy of two ultraluminous X-ray sources and a low-luminosity AGN (Sazonov)

Proposal Abstract

The nature of ultraluminous X-ray sources (ULXs) remains unknown. We do not know whether they host stellar- or intermediate-mass black holes, nor do we have a clear understanding of the accretion process. Similarly poorly studied is accretion onto supermassive black holes in low-luminosity active galactic nuclei (LLAGN). To address these problems, high-sensitivity observations at energies above 10 keV are needed. We propose to add 2+2 Ms of exposure with INTEGRAL in AO9 and AO10 to a 4 Ms exposure to be accumulated in AO7 and AO8 in a unique field where two of the brightest ULXs, M82 X-1 and Holmberg IX X-1, and one of the brightest LLAGN, M81, are located. We will measure the spectra of these sources in the 3-100 keV energy band and study their spectral variability. A preliminary analysis of ~2.5 Ms of observations provided to us so far confirms the feasibility of achieving our scientific goals.

Observation Strategy (Recommended by TAC)

Total of 2 Ms in the standard 5x5 dithering mode, centered on RA, Dec (J12000.0, in degrees) = 148.958, 69.679 (l,b= 141.412, 40.564 degrees).

Proposal grade: A

Data Rights (Recommended by TAC)

Data rights were granted for M821 X-1, Holmberg IX X-1 and M81

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Exposure Map

The exposure maps are in galactic coordinates using the Aitoff projection and units of seconds, and the colour scale is indicated at the bottom. The green lines provide the 50, 200, 350, 500 and 650 ksec contour.