MAXIM: The Blackhole Imager

1. MAXIM: The Blackhole Imager Keith Gendreau Study Scientist Code 662 NASA Goddard Space Flight Center Fiscal Year 2002 IRAD Colloquium…Science and Technology Accomplishments: Dec. 2002

2. Science Driver for MAXIM • Current best estimates for the size of the event horizon of a blackhole: a few microarcseconds • Variability and spectral data describe an x-ray bright region near the event horizon. • Baselines at 1-10Å are a factor of of 1000 shorter than at 1000-10000Å • The MAXIM mission will have resolution of 0.1 as. • Resolve the event horizon • Study physics and dynamics of inner accretion region near event horizon • For Scientific and Technical context, we are exploring MAXIM Pathfinder mission concepts. • Discover where AGN Jets take off • Study Stellar Coronae http://maxim.gsfc.nasa.gov

3. Science Driver for MAXIM

4. Supermassive Blackhole Targets • The distances are calculated assuming a Hubble constant of 65 km/s/Mpc. Accurately determined kinematic black hole masses are denoted by an asterisk. All other black hole masses are estimates based upon reverberation experiments or host galaxy properties. All of these sources are known to possess variable fluxes; we quote a typical value in the 2-10 keV bandpass.

5. Objectives for FY02 • Testbed Development • This year we planned to get fringes in 1-D of a scaled version of the MAXIM X-ray interferometer at ~ 1 keV • Test tolerances of a grazing incidence interferometer • Advance Mission Concepts • Make the Pathfinder mission true stepping stone to the full mission • Look for new methods to point micro-arcsecond imagers • Identify technological tall Poles

6. Accomplishments for the Year: Testbed Development and Results • Detected fringes @ 0.525 keV (23 Å) and 1.49 keV (8.35 Å) with a 650 micron baseline (~0.1” at 1.49 keV) • There are several significant implications of this years work: • We have demonstrated interferometry over a factor of 3 of wavelength within the X-ray band. • Our measurement at 8.35 Å is the shortest wavelength light to have produced fringes in a broadbandpass interferometer. • We have successfully proven a core MAXIM concept Fringes at 8.35 Å 25 November 2002

7. Accomplishments for the Year: Testbed Development and Results L d Beams Cross Flats Detector • Grazing Incidence softens tolerances by ~2 orders of magnitude. Optics that are diffraction limited for normal incidence UV is diffraction limited for grazing incidence X-rays. • Use “simple” optics to keep diffraction limit. • Demonstrated in lab at ~10 Angstroms (1.25 keV). W. Cash et al, Nature 407 14 September 2000 • Demonstrated at GSFC with 23.6 Angstroms 27September 2002 s Fringe Spacing:

8. Accomplishments for the Year: Testbed Development and Results • Penthouse of Bldg 2 • 80 m long X-ray beam line • 25 m source to optics • 50 m focal length • ~ 1mm baseline • (0.25 arcsec at 1 keV) • Fringe Spacings of 75 to 250 microns-> simple vibration suppression at 3 stations

9. Accomplishments for the Year: Mission Concept Development (I) • Improved Grouping of Mirrors: “Periscope” Pairs • “Easy” Formation Flying (microns)- It was nanometers • All s/c act like thin lenses- Higher Robustness • Possibility to introduce phase control within one space craft- an x-ray delay line- More Flexibility • Offers more optimal UV-Plane coverage- Less dependence on Detector Energy Resolution • Each Module, self contained- Lower Risk. • Offers the Pathfinder Mission higher resolution than in our baseline mission • Makes the Pathfinder Mission scalable towards the full Blackhole Imager • Completed an IMDC Study using this concept along with new pointing techniques for new scalable MAXIM-> cost est $550-600M

10. MAXIM Pathfinder • “Easy” Formation Flying (mm control) • Optics in 1 s/c act like a thin lens Accomplishments for the Year: Mission Concept Development (I) Improved Mirror Grouping Pre FY02 Baseline Mirror Grouping Group and package Primary and Secondary Mirrors as “Periscope” Pairs • “Easy” Formation Flying (microns) • All s/c act like thin lenses- Higher Robustness • Possibility to introduce phase control within one space craft- an x-ray delay line- More Flexibility • Offers more optimal UV-Plane coverage- Less dependence on Detector Energy Resolution • Each Module, self contained- Lower Risk. Full MAXIM- the black hole imager • Nanometer formation flying • Primaries must point to milliarcseconds A scalable MAXIM concept.

11. Accomplishments for the Year: Mission Concept Development (I) 1 km Science Phase #2 High Resolution (100 nas) Science Phase #1 Low Resolution (100 mas) Launch 200 km 20,000 km Transfer Stage

12. Accomplishments for the Year: Mission Concept Development (II) • Line-of-Sight Alignment: Pointing sub milli-arcsecond telescopes • Needed to find alternates to using SIM as a star tracker • Completed an ISAL study for the “super startracker” • Compared traditional star tracker approaches to inertial reference frame approaches • Identified specific challenges • Found that *High* Precision Gyroscopes may be the solution • Started a new collaboration with UMD on “Super Fluid Gyroscopes” • Could offer higher sensitivity and a much higher bandpass than the GP-B gyros • Multiple uses

13. Future Work: X-ray Interferometry Testbed • Improve stability of testbed with more thermal control • Attempt to lock in on fringes • Extend the wavelength range of our testbed to the Iron K X-ray line • Interferometry at less than 2 angstroms- an extension of more than an order of magnitude • Our interferometer will work at wavelengths where we know the inner regions of a blackhole are bright • We will need a longer facility • Extend testbed to 2-D • Bring into phase a 3rd set of mirrors • Make larger mirrors • Integration with the Formation Flying Testbed • Compensate for building motion • Provide more definition for mission concept studies