1. The upgraded HET
Hobby-Eberly Telescope Dark Energy Experiment

2. You are Here
Dark Energy Dominates
Inflation??
Big Bang

3. What Controls the Expansion Rate
An Equation is worth a 1000 pictures:
Expansion Rate Radiation Matter Universe Shape Dark Energy
Observing different epochs in the Universe allows us to see the influence of different components. HETDEX probes early epochs, where shape is important.
time

4. Artist Rendition of the Multiverse

5. Dark Energy Ideas Cosmological constant
Modification of General Relativity
Quintessence; a fifth force
Leaking dimensions
Big Bang is modified
Hubble Bubble
Leaking energy from other universes

6. HETDEX is:
blind spectrographic survey on 9.2m Hobby-Eberly Telescope
300 square degrees in 1400 hours (140 nights) over 3 years (taken in 4000 pointings of 20 minutes each); at 1/5 fill, this provides 60 sq deg of sky with spectra
about 0.7 million redshifts from 1.9<z<3.5 (Ly-alpha emitters)
about 1 million redshifts from 0<z<0.5 (OII emitters)
upgraded HET with new top-end, including 22’ field
new instrument VIRUS which is 150 spectrographs (R=750 from 350nm – 550nm), covering 1/5th of the focal plane with 33,500 fibers
one unit spectrograph has been in use since 2006
TIMELINE:

7. HETDEX Funding and Budget
Private
13.0
NSF
8.0
Air Force (NESSI)
4.5 UT
11.0
Munich, AIP
4.0
TAMU
1.0
Oxford
0.5
Total
42.0 M
HET upgrade
17.0
VIRUS
15.0
Software
4.0
Project Office
6.0
Total
42.0 M
Schedule
Take down
7/13
First light
10/15
20 spectrographs
10/16
156 specs
8/17
Survey

8. Wide Field Corrector
Focal Plane
Tracker
Optical Fibers
Spectrographs (VIRUS)
Primary Mirror

9. ESSENCE of HETDEX
380,000 years after the Big Bang
There is a characteristic scale imprinted in the distribution of matter.
It acts like a fingerprint that we use to trace over cosmic time.
Requires about one million galaxies in order to see it.
Today: 13.7 billion years after the Big Bang

10. Example data from a week ago!

11. The Instrument for HETDEX: VIRUS
Visible Integral-field Replicable Unit Spectrograph
Uses idea of industrial replication
150 copies of a simple spectrograph
We’re the only ones doing this
Huge advantages
Cost savings, schedule, low risk
Build a prototype
Funded by the George & Cynthia Mitchell Foundation, McDonald Observatory, MPE, and AIP
VIRUS Prototype

13. Integral Field Unit production
Each IFU is a bundle of 448 fibers split into two slits to feed a VIRUS pair
Simple design maximizes throughput and minimizes cost
Development in collaboration with AIP
nine already delivered
IFU input heads
IFU input
IFU output

14. Example data frame (2.9 million of these in total)

15. What Can HETDEX Do For You
Detection of dark energy
Shape of Universe (curvature) to 0.1%
Best measure of shape of matter distribution early in the Universe.
Best measure of total neutrino mass
Detection of cosmic web in emission
Nature of early galaxies
Black Hole-Galaxy correlations
Star formation at late times
Dark matter in nearby galaxies
Stellar populations at large radii
Map nearby clusters
Galactic structure from stellar kinematics
Study of the first stars