James Larkin Research Areas

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James Larkin - Research Areas

• Extragalactic Astronomy
• Especially focused on the use of Adaptive Optics
  (AO) to observe galaxy evolution
• Infrared Instrumentation
• Focused on instruments for AO systems.

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Galaxy Sizes
WM0.25, WL0.75, Ho70 km/s/Mpc
5 kpc
Good Optical/NIR Seeing
2 kpc
0.5 kpc
Keck Diffraction Limit _at_ 1.6mm
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Galaxy Sizes
Large Nearby Galaxy _at_55 million light years
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Galaxies have Complex Spectra

• Different light production mechanisms dominate
  portions of galaxies spectra and reveal many
  aspects of a galaxies life.
• Only with a combination of Optical (HST), X-Ray
  (Chandra), Thermal IR (SIRTF), Radio (VLA) and
  Near-IF (AO) can we see a galaxy fully.

• Near IR penetrates dust and measures the older
  stars that directly reveal the total number of
  stars formed. (AO)
• Ground based observatories also offer much better
  spectroscopic facilities with new AO spectrographs

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New NIRC2 SurveyLarkin, J. E., Barczys, M.,
Matthews, K. Y., Soifer, B. T., McLean, I. S.,
Thompson, D., Egami, I., Glassman, T. M.,
Wizinowich, P., Le Mignant, D
PSF Star
17 Fields gt300 Galaxies
Example 30x30 Field All Bright objects are
galaxies.
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What do we do

• Observe galaxy fields
• Write custom reduction routines
• Find and extract objects
• Model PSF variations
• Model galaxy components
• Multislit spectroscopy for redshifts (50 zs)
• Build evolving SED models
• Use local galaxy samples to constrain evolution
  of bulges, disks, structure

Original
Model
Residual
PSF star
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Survey conclusions6 Billion Years ago,

• Most galaxies were still recognizable according
  to the
• structural types we see today.
• Low luminosity sources at this time were late
  type spirals.
• gt20 of luminous galaxies have stellar bars.
  Indicates that the disks are dynamically mature.
• Bars are found in 4 of galaxies in HDF at this
  epoch (Van den Bergh, 2002)
• gt20 have close companions that will merge within
  1 Billion years. This implies most large spirals
  have had a minor merger since formation.
• No evidence of major mergers seen in HDF at this
  epoch
• Disks in early type galaxies were comparable in
  size but were significantly (70) brighter in
  infrared than today
• Requires most stars are already in place.
• Most consistent with large disk formation 10-12
  Gyr ago (z2-3) with rapid star formation
  decrease (tlt3 Gyr).

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Next phaseCfAO Treasury Survey (CATS)
2150 nm

• None of our previous fields have HST or other
  deep observations.
• New collaborative project to observe Legacy
  Fields (HST, SIRTF and CHANDRA observations)
• UCLA Barczys, Larkin (co-leader), Wright
• UCSC Nelson(PI), Faber, Guhathakurta, Koo
  (co-leader), Max, Melbourne,
• Steinbring
• UH Chun, Takamiya
• Will take 4 years (starting Oct 2003), and
  require gt40 nights of observing time at Keck,
  Gemini and Subaru.
• NSF CfAO provides a coordinated environment to
  bring these developments together and produce an
  effective educational program.

660 nm
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OSIRISJames Larkin (PI), Andreas
Quirrenbach(PS), Alfred Krabbe(Co-PI), Ted
Aliado, Matthew Barczys, George Brims, John
Canfield, Thomas Gasaway, Evan Kress, David
LaFreniere, Nick Magnone, Michael McElwain,
Juleen Moon, Gunnar Skulason, Inseok Song,
Michael Spencer, David Sprayberry and Jason Weiss

• An AO infrared integral field spectrograph.
• Dissects arcsecond sized regions of the sky in 2
  dimensions
• My main science interest with OSIRIS
• Internal kinematics of distant galaxies (mass
  assembly)
• Other Science Goals
• Jovian planets and moons.
• Kuiper belt objects
• Close companions to stars
• Circumstellar disks
• Galactic Center dynamics and stellar types
• AGN/ circumnuclear interactions
• QSOs, host galaxies

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OSIRIS Status and Schedule

• Essentially all major components are in-house.
• Mechanisms are undergoing lifetime testing.
• Control software is close to complete.
• Major effort going into array controller software
  (SDSU, Leach)
• Preship Review in Early Summer.
• Commissioning in summer and fall 2004.

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Far Future

• Gemini
• Extreme Adaptive Optics Instrument
• Thirty Meter Telescope
• Deployable Integral Field Spectrograph