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Application of Hectochelle - MMT Science Symposium, 06/14/2006
Gábor Fűrész, predoc fellow
Harvard-Smithsonian Center for Astrophysics
Application of Hectochelle:
Dynamical Studies of Open Clusters
Application of Hectochelle - MMT Science Symposium, 06/14/2006Gábor Fűrész - Application of Hectochelle; 06/14/2006, Tucson
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
Application of Hectochelle - MMT Science Symposium, 06/14/2006
The Hectochelle Team
PI: A.SzentgyorgyiDetectors: J.Geary, B.McLeod, S.Amato Optical Design: D.Fabricant, H.EppsOperational Support: N.Caldwell, G.WilliamsSoftware: M.Conroy, J.RollMech Eng: R.Eng, J.Barberis, M.Honsa, P.CheimetsStruct Eng: H.Bergner, R.Fata, M.PieriElec Eng: T.Gauron, D.Weaver Fibers/Calibration: J.ZajacTech Support: F.Collette, W.Brymer, F.Rivera, R.Goddard,
S.NicholsManagement: L.Feldman, C.Osterer, T.Norton, P.SozanskiScience Team: L.Hartmann, D.Latham, A. Dupree,
S.Korzennik, P.Nisenson, R.Noyes, S.BaliunisMMT Staff
“Deputy.PI”: G.Fűrész
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Hectochelle Performance Parameters
A multiobject high resolution (echelle) spectrograph for thepost-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
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Fiber positioner
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Fiber positioner
• Fred and Ginger
• Twin gantry geometry
• Each robot 5 axes (x,y,z,,)
Application of Hectochelle - MMT Science Symposium, 06/14/2006
• 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)
Fiber positioner
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Hectospec (left) and Hectochelle (right) in early phase of integration at the MMT. The Hectochelle is instrumented
with a test fiber slit.
Bench spectrographs: Hectospec and Hectochelle
Application of Hectochelle - MMT Science Symposium, 06/14/2006
• 20 Minute exposure of Kepler field• Color and pincushion present• Slit tilt present
Sample data
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Performance
RMS:
56 m/s
RMS:
225 m/s
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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.
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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)
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: NGC 2264
Radial velocity distribution
- distribution is not gaussian- ~ 3.5 km s-1
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: NGC 2264
Radial velocity vs. spatial distribution
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Model simulation: Finite sheet evolution with gravity,
initially elliptical, uniform :
then forms filament with higher concentrations of mass at ends!
pileup of material at edge, PLUS focal points at ends!
Finite sheet evolution with gravity
Application of Hectochelle - MMT Science Symposium, 06/14/2006
velocity dispersion
Finite sheet evolution with gravity: rotating ellipse
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Finite sheet evolution with gravity – NGC 2264
(GM/R • (r/R))1/2 ~ (G [4000 M]/3.5 pc • (0.55))1/2 ~ 1.6 km/s
faster infall at ends - focal point behavior
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: ONC
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Finite sheet evolution with gravity – ONC
Orion A
Orion B
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Finite sheet evolution with gravity – ONC
Orion A has a similar structure (clumps along a filament) as the Burkert-Hartmann theory predicts
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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
Open cluster kinematics: ONC
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: ONC
Histogram of cluster members:
Average radial velocity is 26.6 km/s
Velocity dispersion ~ 4 km/s
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: ONC
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: ONC
Application of Hectochelle - MMT Science Symposium, 06/14/2006
ONC: triggered star formation?
Application of Hectochelle - MMT Science Symposium, 06/14/2006
NGC 1907 & 1912
age ~250 Myrdistance ~1300 pcseparation ~18 pc
supposed pair(Subramaniam & Sagar, 1999)
photometry:FLWO 48” and MiniCam
target selection for Hectochelle spectroscopy, based on CMD
Open cluster kinematics: M 38
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: M 38
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: M 38
Region C (NGC 1912)total/member 106/45mean RV -0.9 ( 0.7) km/sdispersion 3.8 km/s
Region B (bridge)total/member 57/28mean RV -0.7 ( 1.1) km/sdispersion 3.6 km/s
Region A (NGC 1907)total/member 35/10mean RV -3.3 ( 1.1) km/sdispersion 4.5 km/s
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: M 38
N body simulation using STARLAB: fly-by of two clusters, V=3 km/s
Application of Hectochelle - MMT Science Symposium, 06/14/2006
Open cluster kinematics: M 38
1 = 3 km/s
2 = 3 km/s
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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?
Future Plans
Application of Hectochelle - MMT Science Symposium, 06/14/2006
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.
Future Plans: age determination
Application of Hectochelle - MMT Science Symposium, 06/14/2006