White Dwarfs in the HET Dark Energy Experiment
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Transcript of White Dwarfs in the HET Dark Energy Experiment
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
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
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)
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
(Frieman et al. 2008)
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Destiny of the universe depends critically upon the nature of dark energy!
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
HETDEX field:
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
Flux calibrating the pilot survey:17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Feige 34
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 1:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 2:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 3:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 4:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 5:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Dither 6:
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Feige 34:
VIRUS-P
2.7m HJST
6x120s
V=11.2
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
(Drory 2010)
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
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!
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
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?
17th European White Dwarf Workshop – Tübingen, August 16-20, 2010
Danke! Obrigada!