astrophysical black holes
DESCRIPTION
Astrophysical black holes. Chris Reynolds Department of Astronomy. Topics. Observational evidence for black holes X-ray studies of strong-gravity region First observational studies of BH spin Future directions. Observational evidence for black holes. - PowerPoint PPT PresentationTRANSCRIPT
1
Astrophysical black holesAstrophysical black holes
Chris ReynoldsDepartment of Astronomy
2
TopicsTopics
Observational evidence for black holesX-ray studies of strong-gravity regionFirst observational studies of BH spinFuture directions
3
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
4
QuickTime™ and aAnimation decompressor
are needed to see this picture.
5
Observational evidence for Observational evidence for black holesblack holes
Early X-ray observations [1965] discovered a powerful X-ray source in Cygnus
Cygnus X-1– Binary star system… black
hole in orbit around a massive O-star
– Black hole mass 7-13 M– X-rays produced due to
accretion of stellar wind from O-star
– 2kpc away
6
How do we know the black How do we know the black hole mass?hole mass?
Period 5.6 days K = V sin i = 75km/s Newtonian analysis…
– MBH>f– Cyg X-1… f=0.24MBH
Feed in knowledge of i and companion mass… M=7-13Msun
6 “golden” cases with f>3Msun
Brocksopp et al. (1998)
7
8
9A. Ghez (UCLA)
Strong evidence for a 3-4 million solar mass BH at the Galactic Center (closest stellar approach only 40AU!)
10Chandra+VLA image of GC (Baganoff et al. 2001)
X-ray studies of black holesX-ray studies of black holes
11
MCG-6-30-15 (Seyfert gal)(LX~1036 W)
3C273 (Quasar)LX ~1038 W
12
13
X-ray “reflection” imprints well-defined features in the spectrum
14
15
Relativistic effects imprint characteristic profile Relativistic effects imprint characteristic profile on the emission line…on the emission line…
Iron line profile inMCG-6-30-15
16MCG-6-30-15 Suzaku(Miniutti et al. 2006)
17
Also see Suzaku results on broad iron lines at this meeting:• MCG-5-23-16 (Reeves et al.)• NGC 3516 (Markowitz et al.)
Systematic surveys of the XMM archive are showing that ~1/2 of type-1 AGN show broad iron lines (largely confirming ASCA results)
MCG-5-23-16 (Dewangan 2003)
NGC2992
IRAS 18325 (Iwasawa 2004)
18
19Brenneman & Reynolds (2006)
Assuming no emission from within rms
a>0.987 (formal 90% limit)
XMM analysis of MCG-6-30-15
20
Black Hole Quasi-periodic Black Hole Quasi-periodic oscillationsoscillations
High-frequency QPOs– Comparable frequency to
orbital frequency in inner accretion flow
– Often found in pairs with 3:2 ratio
Stable frequencies– probably determined by
gravitational potential– Could be an excellent probe
of the mass and spin!!
21
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
22
23
QPO theoryQPO theory Lack of standard QPO
theoretical framework is problem
Global modes of accretion disk– “Diskoseismology”; Wagoner,
Nowak, Kato…– Produce g-, p-, and c-modes– Linear theory… no natural
explanation for 3:2 ratio Resonance model
– Parametric resonance between vertical/radial epicyclic frequencies (Abramowicz & Kluzniak)
– Source of free energy?
Fundamental g-mode (Nowak & Wagoner)Movie by Mike Nowak
24
The Future of BH X-ray StudiesThe Future of BH X-ray Studies
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
Armitage & Reynolds (2004)
Dynamical timescale variability… probes orbital motions in accretion disk
25
Powerful probe of turbulent disk physics. Also, arcs approximately trace test-particle Keplerian orbits in = plane.
Iwasawa et al. (2004)
26
Light crossing timescale allows reverberation effects to be studied.
27Chandra Deep Field
28
Constellation-X simulations…Constellation-X simulations…
Simulated 100ks; F2-10=10-12erg/s/cm2 Simulated 1Ms; z=1; F2-10=10-14erg/s/cm2
~4 such source per Con-X field
29
Imaging a black holeImaging a black holemm-VLBImm-VLBI
30
Imaging a black holeImaging a black holeMicro-arcsecond X-ray Imaging Micro-arcsecond X-ray Imaging
Mission (MAXIM)Mission (MAXIM)
HST (0.1 arcsec)
MAXIM (0.05 -arcsec)
31
~20,000 km
Current MAXIM conceptCurrent MAXIM conceptGroup 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.
~500-1000 m Baseline
A scalable MAXIM concept.