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Gábor Fűrész, predoc fellow Harvard-Smithsonian Center for Astrophysics

Application of Hectochelle:. Dynamical Studies of Open Clusters. Gábor Fűrész, predoc fellow Harvard-Smithsonian Center for Astrophysics. Talk outline. Talk overview Brief description of the Hectochelle Some scientific programs underway with Hectochelle:

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Gábor Fűrész, predoc fellow Harvard-Smithsonian Center for Astrophysics

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  1. Application of Hectochelle: Dynamical Studies of Open Clusters Gábor Fűrész, predoc fellow Harvard-Smithsonian Center for Astrophysics

  2. Talk outline Talk overview Brief description of the Hectochelle Some scientific programs underway with Hectochelle: NGC 2264 – signs of cluster formation Orion Nebula Cluster – birth of a cluster NGC 1907 & 1912 – interacting open clusters Plans for the future Gábor Fűrész - Application of Hectochelle; 06/14/2006, Tucson

  3. The Hectochelle Team PI: A.Szentgyorgyi Detectors: J.Geary, B.McLeod, S.Amato Optical Design: D.Fabricant, H.Epps Operational Support: N.Caldwell, G.Williams Software: M.Conroy, J.Roll Mech Eng: R.Eng, J.Barberis, M.Honsa, P.Cheimets Struct Eng: H.Bergner, R.Fata, M.Pieri Elec Eng: T.Gauron, D.Weaver Fibers/Calibration: J.Zajac Tech Support: F.Collette, W.Brymer, F.Rivera, R.Goddard, S.Nichols Management: L.Feldman, C.Osterer, T.Norton, P.Sozanski Science Team: L.Hartmann, D.Latham, A. Dupree, S.Korzennik, P.Nisenson, R.Noyes, S.Baliunis MMT Staff “Deputy.PI”: G.Fűrész

  4. Hectochelle Performance Parameters A multiobject high resolution (echelle) spectrograph for the post-conversion MMT, operating at f/5 • Resolution: 34,000 • Single order • Order separation by filter • Number of fibers: 240 • Shares HectoRobot as Hectospec • Number of available passbands, typically 150Å wide • Typical efficiency: 8% • Precision radial velocity (PRV) in development

  5. Fiber positioner

  6. Fiber positioner • Fred and Ginger • Twin gantry geometry • Each robot  • 5 axes • (x,y,z,,)

  7. Fiber positioner • Positions 300 optical • fibers on curved 1º • focal plane in 5 • minutes with < 25µ • accuracy. • Fibers magnetically • attached to focal • surface. • Positioner consists of • two robots operating • simultaneously. • Plate scale is • 174μ/arcsec • Fibers are 250µ dia. • (1.4 arcsec)

  8. Bench spectrographs: Hectospec and Hectochelle Hectospec (left) and Hectochelle (right) in early phase of integration at the MMT. The Hectochelle is instrumented with a test fiber slit.

  9. Sample data • 20 Minute exposure of Kepler field • Color and pincushion present • Slit tilt present

  10. Performance RMS: 225 m/s RMS: 56 m/s

  11. Examples of Science Programs In Progress • Surveys of Young Clusters - Hartmann, Calvet et al. • Kepler Ground Segment – Latham, et.al. • Internal Dynamics of Local Group dSphe – Olszewski, Mateo et al. • & Majewski et al. • PRV Extrasolar Planet Searches – Korzennik, Noyes, Latham, &c. • Wisconsin Open Cluster Survey (WOCS) – Mathieu, Latham, et al. • Studies of Globular Cluster Spitzer Sources – Dupree, et al. • Absorption line distance to the Cygnus Loop – Eriksen • Chromospheric Activity of Solar-Type Stars - Baliunis et al. • Open Cluster Dynamics – Fűrész & Hartmann, et al.

  12. Open cluster kinematics: NGC 2264 targets based on a list of X-ray sources (Ramírez et al. 2004) and later 2MASS sources added (selected in color-color diagram)

  13. Open cluster kinematics: NGC 2264 Radial velocity distribution - distribution is not gaussian - s~ 3.5 km s-1

  14. Open cluster kinematics: NGC 2264 Radial velocity vs. spatial distribution- matching molecular gas key: Hectochelle targets in a given RV bin Ha emission stars form Reipurth et al. 2004 13CO channel maps from Ridge et al. 2003

  15. Open cluster kinematics: NGC 2264 Radial velocity vs. spatial distribution

  16. Finite sheet evolution with gravity Model simulation: Finite sheet evolution with gravity, initially elliptical, uniform : • pileup of material at edge, PLUS focal points at ends! • then forms filament with higher concentrations of mass at ends!

  17. velocity dispersion Finite sheet evolution with gravity: rotating ellipse

  18. Finite sheet evolution with gravity – NGC 2264 faster infall at ends - focal point behavior (GM/R • (r/R))1/2 ~ (G [4000 M]/3.5 pc • (0.55))1/2 ~ 1.6 km/s

  19. Open cluster kinematics: ONC

  20. Finite sheet evolution with gravity – ONC Orion B Orion A

  21. Finite sheet evolution with gravity – ONC Orion A has a similar structure (clumps along a filament) as the Burkert-Hartmann theory predicts

  22. Open cluster kinematics: ONC Hectochelle field of view is shown in cyan. Likely cluster members based on RV: Green – errors less than 1 km/s Red- errors greater than 1 km/s Blue- Observed on both nights Size of dots is proportional to quality of radial velocity: larger dot-better velocity fit IRAC image of the ONC with cluster members

  23. Open cluster kinematics: ONC Histogram of cluster members: Average radial velocity is 26.6 km/s Velocity dispersion ~ 4 km/s

  24. Open cluster kinematics: ONC

  25. Open cluster kinematics: ONC

  26. ONC: triggered star formation?

  27. Open cluster kinematics: M 38 NGC 1907 & 1912age ~250 Myr distance ~1300 pc separation ~18 pc supposed pair (Subramaniam & Sagar, 1999) photometry:FLWO 48” and MiniCam target selection for Hectochelle spectroscopy, based on CMD

  28. Open cluster kinematics: M 38 Photometric result: average color inbetween the clusters is closer to the value of clusters, rather than field stars: hint for a tidal bridge? also, signs for tidal tails

  29. Open cluster kinematics: M 38

  30. Open cluster kinematics: M 38 Region C (NGC 1912) total/member 106/45 mean RV -0.9 ( 0.7) km/s dispersion 3.8 km/s Region B (bridge) total/member 57/28 mean RV -0.7 ( 1.1) km/s dispersion 3.6 km/s Region A (NGC 1907) total/member 35/10 mean RV -3.3 ( 1.1) km/s dispersion 4.5 km/s

  31. Open cluster kinematics: M 38 N body simulation using STARLAB: fly-by of two clusters, DV=3 km/s

  32. Open cluster kinematics: M 38 s1 = 3 km/s s2 = 3 km/s

  33. Future Plans Histogram of stars from our sample which have ages from Hillenbrand (1997). Ages were determined by evolutionary track fitting. What is the dispersion of so-called old and young stars from our sample?

  34. Future Plans: age determination Empty Regions Why are these here? If all off-cloud stars are ONC members, there should be a continuous flow of stars, as in Trapezium region (yellow rectangle). Possible explanation is the off-cloud stars are part of another, older association: Orion OB1c To answer this, age determination is necessary for more stars.

  35. hectochelle@cfa.harvard.edu

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