Upload
norman-webster
View
213
Download
0
Tags:
Embed Size (px)
Citation preview
The Future of Direct Supermassive Black Hole Mass
Measurements
Dan Batcheldor
Rochester Institute of Technology
- The Role of SMBHs measurements.- Current Status of SMBH masses.- Mass estimate techniques.- Observational requirements.- Current and future abilities.
Dan Batcheldor, RIT, Astro2020 2
The Role of SMBHs
• Energy output, variability and longevity of AGN require accretion onto a SMBH.
• QSO number density higher in the past, expect to find relic SMBHs in local quiescent galaxies.
• Observed correlations between SMBH and host bulge properties.
• Correlations used to calibrate secondary techniques for higher redshift SMBH mass estimates.
• See review by Ferrarese & Ford (2005).
Dan Batcheldor, RIT, Astro2020 3
Current Status
• Only 3 cases that require a SMBH: NGC 4258, Circinus, Milky Way = 3.7(0.2) x 106 M
• ~ 30 direct mass estimates (106 M - 3.6 x 109 M)
• 25 with resolved spheres of influence up to 240 Mpc• Mostly early type hosts, mostly observed with HST.
• Modes: ~ 108 M, ~ 20 Mpc.
• Estimates from different methods may not be consistent.
Dan Batcheldor, RIT, Astro2020 4
Mass Measurement Techniques
• Resolved Proper Motions – Milky Way only
• 22 GHz water masers (NGC 4258)– Alignment issues– AGN required
• Asymmetric Fe K emission line (NGC 3516)– AGN required– Rev map, but crossing times < integration times
• Nucleated disk gas dynamics• Stellar dynamics
Dan Batcheldor, RIT, Astro2020 5
Mass Measurement Techniques
Gas Dynamics• Assumes rotating nuclear gas/dust disk. tot= stars + bh
• Relies on bright emission lines.• Keplerian rotation relatively easy to model and
positive signature of SMBH.• Arguments over non-gravitational forces.• Nuclear disks not present in all galaxies.• Inclination unconstrained in many cases.
Dan Batcheldor, RIT, Astro2020 6
Mass Measurement Techniques
Stellar Dynamics• 2 - integral models (Jeans equations).• 3 - integral models (orbital super-positioning).• Observed kinematics are purely gravitational.• Applicable to all galaxies.• Requires the use of faint stellar absorption lines at
low surface brightness. • Effected by extinction.• Systematic uncertainties.
Dan Batcheldor, RIT, Astro2020 7
Observational requirements
• Gas and stellar dynamics complementary. • 2D kinematics essential in both cases.• High sensitivity (STIS needs 100 orbits for
S/N 50 in M87 continuum).
• High resolution. Sphere of influence of 108 M
at 10 Mpc ( = 200 km s-1) is ~ 0.2 arcsec.
Dan Batcheldor, RIT, Astro2020 8
• Equate diffraction limit to sphere of influence.
• Evaluate for = 5200, 6563 & 8500Å.
• Assume modal distance values from current SMBH mass estimates.
• Consider sensitivities…
Current abilities
Dan Batcheldor, RIT, Astro2020 9
Future abilities
• JWST + NIRSpec.– At 9500Å R = 35, at 1.9m R = 2200 (135 km s-1) + IFU– At 8500Å R = 39, at 2.3m R = 2500 (120 km s-1) + IFU
• JWST + MIRI. – At 7.6m R = 3000 + IFU
• 16 m + ??
• TMT + ??
Dan Batcheldor, RIT, Astro2020 10
Summary
• Galaxy and SMBH formation and evolution intimately linked.
• 30 mass estimates over limited ranges.• Gas and stellar dynamics are complimentary
methods.• HST is exhausted, JWST limited abilities• To fully explore the M- plane
– 30+ m diffraction limited facility
– High spectral resolution in optical and near-mid IR