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The Black Hole Mass – Pitch Angle Relation

The Black Hole Mass – Pitch Angle Relation. Julia Kennefick University of Arkansas Fayetteville Department of Physics Arkansas Center for Space and Planetary Science. Toward a Supermassive Black Hole Mass Function. The Arkansas Galaxy Evolution Survey (AGES). Principles Dan Kennefick

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The Black Hole Mass – Pitch Angle Relation

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  1. The Black Hole Mass – Pitch Angle Relation Julia Kennefick University of ArkansasFayetteville Department of Physics Arkansas Center for Space and Planetary Science Toward a Supermassive Black Hole Mass Function 7th Korean Astrophysics

  2. The Arkansas Galaxy Evolution Survey (AGES) • Principles • Dan Kennefick • Julia Kennefick • Claud Lacy • Marc Seigar (UALR) • Postdocs • Joel Berrier(Rutgers) • Patrick Treuthardt(Adler Planetarium) • UAF Graduate Students • R. Scott Barrows (Ph.D.) • Ben Davis • Doug Shields • J. Adam Hughes • Amanda Schilling • JazminBerlanga-Medina • Kim Zoldak • Jon Bessler • Michael Fusco 7th Korean Astrophysics

  3. Outline • Classification of Galaxies • The Black Hole Mass – Pitch Angle Relation • Measuring Pitch Angle • A Local Black Hole Mass Function of Late Type Galaxies • Why does this work? – A little theory • Current and Future Work 7th Korean Astrophysics

  4. “Early Types” “Late Types” 7th Korean Astrophysics

  5. Which came first, the black hole or the galaxy? • Current questions center on structure and galaxy formation and evolution • Do black holes “seed” galaxies, or do they form as the galaxy collapses? • Need to determine what galaxies are like now, and what they were like in the past, including their central masses • Build a “black hole mass function” – number of black holes as a function of mass and time 7th Korean Astrophysics

  6. Why Spirals? • Most correlations involve the bulge of the galaxy, but bulge features can be difficult to measure in spirals. Therefore, less work done on spirals to date. • Lots of galaxies are spirals – 70% in the field • Cleaner histories – fewer mergers • Represent the lower mass end of the BHMF – relic AGN • Local BHMF can be used to constrain AGN accretion rates Photo T. Davis 7th Korean Astrophysics

  7. Are Pitch Angle and Central Mass Related? • Hints from work by Seigar et al. that they might be • D. Kennefick suggests we look at M vs. P for a sample of local galaxies • Seigar measures P for a sample of 28 galaxies with measured or estimated central black hole masses (13 direct, 11 from sigma, 4 limits) Early version from Seigar et al. 2008 7th Korean Astrophysics

  8. Spiral Arm Pitch Angle • Most disk galaxies are found to have a logarithmic spiral structure • This results in a constant pitch angle, P, over the extent of the spiral arms 7th Korean Astrophysics

  9. How do you measure P? • 2DFFT code from Saraiva Schroeder et al. (1994) Based on FOURN routine in Numerical Recipes • Decomposes observed distributions into a superposition of logarithmic spirals of different P’s and number of arms, m. • p is equivalent to frequency and then pitch angle, P or ϕ, is like a wavelength. NGC 5054 Davis et al. 2012, ApJS, 199, 33 7th Korean Astrophysics

  10. How do you measure P? Deproject Star subtract 7th Korean Astrophysics

  11. How do you measure P? • Where do you start? 7th Korean Astrophysics

  12. How do you measure P? • Compute P over all possible inner radii out to some maximum radius and then average over the stable region. • The quoted error will be (largely) the variation of the pitch angle over the stable region, although currently we are bump those up a bit for objects with short stable regions. 7th Korean Astrophysics

  13. How do you measure P? • NGC 5054, m=3 harmonic mode dominates • Red contours show a inverse FFT of spiral arms with P=-40°.60 from 77-456 pixels (20”-118”), over about 75% of the galaxy NGC 5054 7th Korean Astrophysics

  14. How do you measure P? NGC 5054 “Raw” Galaxy: P=-24°.5 ± 12°.8 Symmetrical component: P=-25°.6 ± 3°.7 7th Korean Astrophysics

  15. How do you measure P? • Sometimes you need to select a different outer radius. • P = 19°.1 ± 4°.8 vs. P=16°.3 ± 3°.2 M51 7th Korean Astrophysics

  16. How do you measure P? • Sometimes things work out just fine… • P= -19°.4 ± 3°.2 NGC 7083 7th Korean Astrophysics

  17. New Results for M-P relation • Updated methodology for measuring P • More masses available • All masses are “directly” measured • χ2 = 4.68 with a scatter of 0.38 dex. • Pearson Rank Correlation Coefficient test gives -0.81, a strong anti-correlation with a 99.7% significance, a 3-σ result. star and gas dynamics (10) reverberation mapping (12) masers (12) Berrieret al., 2013, ApJ 7th Korean Astrophysics

  18. How does it compare to M-σ? masses from M-σ σ’s from Ferrarese (2002) Scatter of spiral galaxies about the M-σ relation is ~0.56 dex (Gultekinet al. 2009) 7th Korean Astrophysics

  19. Local Black Hole Mass Function • Sample selected from Carnegie-Irvine Galaxy Survey 0f 605 galaxies (Ho et al. 2011) • Volume limited to z=0.0057 (DL = 25.4 Mpc) and MB=-19.12 • 140 spiral galaxies within VC = 3.37 x 104 (Mpc/h67.77)3 and tL≤ 82.14 (Myr/h67.77) 7th Korean Astrophysics

  20. Multi-armed Galaxies • While two armed galaxies are the most common type, three armed galaxies are also found fairly frequently. Galaxies with four or more arms often represent flocculents where the number of arms present can be hard to determine by eye. 7th Korean Astrophysics

  21. Pitch Angle and Mass Distributions Mass peaks around 107 for late types, compared to 108 for ellipticals Each galaxy modeled as a normalized Gaussian, with the error as the standard deviation. Errors in mass also include uncertainties in M-P relation, giving a smoother curve 7th Korean Astrophysics

  22. Local Black Hole Mass Function • BHMF generated from pitch angle distribution. • Errors determined using a Monte Carlo sampling of the 128 measured galaxies, with pitch angles randomly generated from the data with a Gaussian distribution within 5σ of each measured value. • The M-P relation was also allowed to vary within its uncertainties. Davis et al., accepted to ApJ 7th Korean Astrophysics

  23. Other BHMF’s Late types • Marconi uses many steps… • Vika uses more distant galaxy sample, perhaps missing dimmer galaxies • We can include brighter galaxies as well… 7th Korean Astrophysics

  24. What about non-locally? • Looking at evolution in pitch angle as a function of time. • Using GOODS fields imaging • Simulations • Numerical modeling • Selection efficiencies • Signal filtering z= 0.410 (4.3 Gyr) P = 33.5 ± 5.8 z= 0.298 (3.4 Gyr) P = -23.1 ± 4.4 z= 0.486 (4.9 Gyr) P = -17.5 ± 3.7 z= 0.595 (5.7 Gyr) P = -27.7 ± 13.1 Shields et al., in prep. 7th Korean Astrophysics

  25. Spiral AGN in GOODS • Found 3 AGN with spiral structure and existing spectra with Mg II line • Preliminary results are consistent with local M-P relation • Need a larger sample 7th Korean Astrophysics

  26. The GOODS Sample z = 1.2 is 8.5 Gyr light travel time Masses determined from existing spectroscopy of GOODs galaxies, using the broad Mg II line and appropriate scaling relations. 7th Korean Astrophysics

  27. Type -1 Project Design • SDSS DR7 quasar catalog – 105,783 sources (at least one broad emission line) • Requiring extended structure and z < 1.0 – 4124 sources • Examine image cutouts – 221 sources (z < 0.64 – 5.9 Gyr) • Prefer 20 pixel radius in the galaxy images to measure P • Imaging: • SDSS imaging for z < 0.15, • KPNO pODI at WIYN for 0.1 < z < 0.3 (3 nights in Nov.) • HST for z > 0.25 (2.9 Gyr) 7th Korean Astrophysics

  28. Type-1 Imaging Goals • 221 spiral type-1 AGN from SDSS DR7 quasar catalog • HST and KPNO proposals for higher resolution imaging • Four objects with existing HST imaging • Find that we can measure P in SDSS imaging data out to at least z = 0.15 7th Korean Astrophysics

  29. KPNO in November • The Milky Way would extend 6.6 arcsec on the sky at z = 0.3 • Pixels are 12 μm square • Giving a pixel scale 0.11 arcsec/pixel • ~30 pixels over which to measure P 7th Korean Astrophysics

  30. Why should this work? • One of the first qualitative observations of galaxies – the Hubble Sequence: galaxies with tighter arms have bigger bulges. • That black hole mass depends on the mass of the central galactic bulge is now well established. • Spiral density wave theory – standing waves • pitch angle (i) – wavelengthdisk mass density (σ) – density of mediumcentral mass (M) – tension • To be continued… Shu (1984) in the case of Saturn (bulge dominated). 7th Korean Astrophysics

  31. Conclusions • Discovered a possible correlation between central black hole mass and pitch angle in disk galaxies • Developed a robust methodology for measuring P • Confirmed the M-P relation in a sample of galaxies with direct measurements of their central black hole masses. • M-P relation has the lowest scatter of any method currently used to estimate the mass of SMBH’s residing in spiral galaxies. • Computed a local black hole mass function for late-type galaxies • Developing a sample of more distant galaxies to explore evolution of the M-P relation for use at earlier times. • Physical basis for relation – standing waves 7th Korean Astrophysics

  32. Future Work Needed • Need to address image quality – signal filtering • Need to address selection effects to estimate completeness • Surface brightness • Redshift • Inclination angle • Pitch Angle • Need a larger sample • pODI at WIYN in November for higher-res imaging data • Explore HST archive • Type-2 AGN (sigma proxy) 7th Korean Astrophysics

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