Wednesday, March 04, 2009

International X-ray Observatory (IXO) white papers for Astro2010

Following on from this morning's post on Astro2010 Decadal Survey science white papers I should mention that the aim of my white paper (and various other white papers) is ultimately to emphasize the need for the US to engage in building and launching the International X-ray Observatory (IXO).

In terms of the science I am interested in, only IXO will have the capability to perform spectral-imaging of diffuse plasmas with high enough spectral resolution and high enough sensitivity to tell us what the rate of ejection from galaxies of gas, energy and newly-synthesized elements into the intergalactic medium is.

This entails being able to measure the velocity of the hot X-ray-emitting plasmas that drive superwinds in a sample of starburst galaxies covering a broad range in galaxy mass, which is impossible with the current generation of observatories, or even future non-X-ray observatories like HST/COS or NGST.

IXO, even if fully funded by all the international groups involved (NASA, ESA and JAXA), would have a launch date of around 2020. JAXA's ASTRO-H will have been launched well before then, around 2013 if all goes to plan, and it should be able to measure wind velocities in one or two of the brightest starburst-driven winds. These will be historic measurements, but won't be enough to establish how or if wind velocities vary with galaxy mass or star formation intensity. Ultimately we need to observe a decent sample, and IXO will be able to measure wind speeds more accurately in more objects.

Ultimately there are a broad range of pressing astrophysical questions that can only be answered with an observatory-class X-ray mission, which is what the broad range IXO white papers aim to demonstrate to the Decadal Survey panels. The full list of IXO-related Astro2010 science white papers (including mine) can be found here.

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