White Dwarfs in the HET Dark Energy Experiment
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Transcript of White Dwarfs in the HET Dark Energy Experiment
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White Dwarfs in the HET Dark Energy Experiment
Bárbara G. Castanheira
The University of Texas at AustinUniversität Wien
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
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Hobby-Eberly Telescope
Location: McDonald Observatory (30° 40' N)
Low cost: 15-20% of the cost of a 9 m telescope
Primary mirror: 11.1 x 9.8 m (9.2 m effective aperture)
91 hexagonal mirrors
Fixed elevation angle of 55o (tilted Arecibo design)
Access 81% of the sky
Queue schedule
Instruments: HRS, LRS, MRS
Model for SALT
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
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HETDEX: HET Dark Energy Experiment
Goal: probe dark energy
Observations: ~ 1400 hours in 3 years
Technique: expansion of the universe at 0<z<4
Main targets: Lyman-α emitting galaxies
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
(Hill et al. 2008)
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Dark energy:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Supernovae discovery of accelerated expansion
Within GR: smooth energy with large negative pressure
75% of the universe
Acceleration began at z~0.4 and t~10Gyr
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(Frieman et al. 2008)
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Destiny of the universe depends critically upon the nature of dark energy!
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HETDEX field:
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VIRUS-P Review: Visual Integral-field Replicable Unit
Spectrograph - Prototype
1.9’x1.9’ FOV at 2.7 m HJST
1/3 fill factor
Largest FOV of any existing IFU
4.2’’ diameter fibers on sky
3500-5800Å wavelength range
R=1000 @ 5000Å
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
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Flux calibrating the pilot survey:17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Feige 34
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Dither 1:
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Dither 2:
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Dither 3:
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Dither 4:
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Dither 5:
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Dither 6:
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Feige 34:
VIRUS-P
2.7m HJST
6x120s
V=11.2
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
HETDEX details:150 VIRUS3500-5500Å~3400 spectraFOV 22arcminResolution ~5Å~140 nights, 3 years
PARALLEL SURVEY
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(Drory 2010)
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
White Dwarfs in HETDEX
~20000 White Dwarfs Magnitude limited sample For V=22, S/N=3 Main and Parallel surveys
A powerful survey!
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
HETDEX current status:
Schedule: late 2011 VIRUS-P at HET Replication of spectrographs Software (CURE or VACCINE & DIAGNOSE) Additional science
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
White dwarf science goals:
WD Luminosity Function New candidates of pulsators (2.1m) New “flavors” of WDs?
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17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Danke! Obrigada!