white dwarfs in the het dark energy experiment bárbara g. castanheira the university of texas at...
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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
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!