Scientific Papers

Papers with Instrument Focus for HETDEX
Papers with Theory and Observational Focus for HETDEX
Papers with Additional Science

Summary Document Abstract & Download

The solution to the problem of dark energy will require a fundamental shift in our understanding of the universe, and acceptance of any model will require signiﬁcant corroboration with observations. The Hobby-Eberly Telescope Dark Energy Experiment, HETDEX, oﬀers a technically clean and observationally robust approach to measuring the eﬀects of dark energy. The project has three parts: upgrade of the HET to have a 22 ′ diameter ﬁeld-of-view, deployment of the VIRUS integral ﬁeld spectrograph, and completion of a wide ﬁeld survey to constrain the evolution of dark energy. In 1400 hours of observations on the Hobby-Eberly Telescope, we will obtain approximately 0.8 million redshifts of Lyman-α emitting galaxies. This survey will determine the local Hubble expansion at z = 2.4 and angular diameter distance out to z = 2.4 to 0.8% each and the growth of structure at z = 2.4 to 2%. Our approach is to observe 420 contiguous square degrees with a 1/7 ﬁll factor with the instrument VIRUS, composed of 75 integral ﬁeld units feeding 150 spectrographs. With a spectral range of 350–550 nm and spectral resolution of 6.4˚A, we can identify Lyman-alpha emitting galaxies at 1.9 < z < 3.5. HETDEX further will measure curvature of the universe to about 0.1%, which is over a factor of ten better than current projects; this measurement of curvature will then be leveraged by all late-time dark energy experiments since there is a degeneracy of curvature with dark energy. Thus, HETDEX strongly complements future and ongoing studies. With no theoretical guidance as to the nature of dark energy, HETDEX takes the approach of exploring a new part of parameter space as well as signiﬁcantly reducing uncertainties on the eﬀect of dark energy at late times. HETDEX is optimized for measures of the expansion history, but there is signiﬁcant additional science from the survey (e.g., spectra of a 0.25 million stars and 1.4 million other galaxies); given its capability, VIRUS will remain the primary instrument for HET for many years after completion. VIRUS will also be operated in a parallel mode with the other HET instruments, so that after 10 years of HET operation, we have the ability to increase the area surveyed by VIRUS by a factor of 5–10. This mode will have very strong scientiﬁc implications for a large variety of science, for example, direct detection of the cosmic web, new regimes for studying Galactic structure, ﬁnding the most metal poor stars, constraints on non-Gaussianity, and probes of outer regions of nearby galaxies for measures of dark matter and star formation. All of these investigations are enabled by VIRUS and HETDEX but will require additional organizational structure and data analysis not currently budgeted.

The signiﬁcant insights on dark energy, the large database with substantial overall science, and the availability of a unique and powerful integral ﬁeld spectrograph that takes at least 33,600 spectra per exposure on the HET will have a broad impact on the astronomy community. The large, blind spectroscopic capability opens new regions of phase space (such as the emission-line universe) for general use. Also, given the importance of dark energy and the ﬁnancial investment from the public, we must reach beyond the science community. With dark energy, the astronomical community has an extraordinary opportunity to engage the public in a way that is rarely possible. We are creating a signiﬁcant outreach component involving the McDonald Observatory Visitors Center and Stardate radio. We also have a popular webpage (hetdex.org, which has 0.4M visits as of March 2009) that we continually update. We plan to exploit fully HETDEX in this manner.

Download the full HETDEX Summary document

Papers with Instrument Focus for HETDEX

Adams, J.J., Hill, G.J., and MacQueen, P.J., 2008, "Volume Phase Holographic Grating Performance on the VIRUS-P Instrument", Proc. SPIE, 7014-258

Booth, J. A., MacQueen, P. J., Good, J. M., Wesley, G. L., Hill, G. J., Palunas, P., Segura, P. R., Calder, R. E., 2006, "The wide field upgrade for the Hobby-Eberly Telescope", Proc. SPIE, 6267, 128

Goessl, C. A., Drory, N., Relke, H., Gebhardt, K., Grupp, F., Hill, G., Hopp, U., Koehler, R. & MacQueen, P., 2006, "The VIRUS data reduction pipeline", Proc. SPIE, 6270, 66

Goessl, C.A., Hopp, U., Koehler, R., Grupp, F., Relke, H., Drory, N., Gebhardt, K., Hill, G., and MacQueen, P., 2007, "The VIRUS Emission Line Detection Recipe", Astronomical Data Analysis Software and Systems XVI, 376, 281

Good, J.M., Hill, G.J., Mollison, N.T., Vattiat, B.L., Murphy, J.D., Klez, A, Roth, M.M., MacQueen, P.J., Rafal, M.D., Savage, R.D., Smith, M.P., Bayless, A.J., 2008, "Current Status of the HETDEX Fiber Optic Support System", Proc. SPIE, 7014-280

Hill, G. J.; MacQueen, Phillip J.; Tejada, Carlos; Cobos, Francisco J.; Palunas, Povilas; Gebhardt, Karl; Drory, Niv, "VIRUS: a massively replicated IFU spectrograph for HET", 2004, Proc. SPIE, 5492, 251

Hill G.J., MacQueen, P.J., Palunas,P., Kelz A., Roth, M.M., Gebhardt, K., Grupp, F., 2006 "VIRUS: a hugely replicated integral field spectrograph for HETDEX", New AR, 50, 378

Hill, G. J., MacQueen, P. J., Tufts, J. R., Kelz, A., Roth, M. M., Altmann, W., Segura, P., Gebhardt, K., & Palunas, P., 2006, "VIRUS: a massively replicated integral-field spectrograph for HET", Proc. SPIE, 6269, 79

Hill, G.J., MacQueen, P.J., Smith, M.P., Tufts, J.R., Roth, M.M., Kelz, A., Adams, J.J., Drory, N., Grupp, F., Barnes, S.I., Blanc, G.A., Murphy, J.D., Altmann, W., Wesley, G.L., Segura, P.R., Good, J.M., Booth, J.A., Bauer, S-M., Popow, E., Goertz, J.A., Edmonston, R.D., & Wilkinson, C.P., 2008, "Design, construction, and performance of VIRUS-P: the prototype of a highly replicated integral field spectrograph for the HET", Proc. SPIE, 7014, 257

Kelz, A., Bauer, S. M., Grupp, F., Hill, G. J., Popow, E., Palunas, P., Roth, M. M., MacQueen, P. J., & Tripphahn, U., 2006, "Prototype development of the integral-field unit for VIRUS", Proc. SPIE, 6273, 121

Murphy, J.D., Palunas, P., Grupp, F., MacQueen, P.J., Hill, G.J., Kelz, A. & Roth, M.M., 2008, "Focal ratio degradation and transmission in VIRUS-P optical fibers", Proc. SPIE, 7018-104

Savage, R.D., Booth, J.A., Gebhardt, K., Good, J.M., Hill, G.J., MacQueen, P.J, Rafal, M.D., Smith, M.P., & Vattiat, B.L., 2008, "Current status of the Hobby-Eberly Telescope wide field upgrade and VIRUS", Proc. SPIE, 7012-9

Smith, M.P., Hill, G.J., MacQueen, P.J., Altman, W., Goertz,, J.A., Good, J.M., Segura, P.R., Wesley, G.L., 2008, "Mechanical design of VIRUS-P for the McDonald 2.7m Harland J Smith Telescope", Proc. SPIE, 7014-259

Smith, M.P., Mulholland, G.T., Booth, J.A., Good, J.M., Hill, G.J., MacQueen, P.J., Rafal, M.D., Savage, R.D., Vattiat, B.L., "The cryogenic system for the VIRUS array of spectrographs on the Hobby Eberly Telescope", 2008, Proc. SPIE, 7018-117

Tufts, J.R., MacQueen, P.J., Smith, M.P., Segura, P.R., Hill, G.J., Edmonston, R.D., 2008, "VIRUS-P: camera design and performance", Proc. SPIE, 7021-10

Papers with Theory and Observational Focus for HETDEX

Hill, G. J. Gebhardt, Karl; Komatsu, Eiichiro; MacQueen, Phillip J., "The Hobby-Eberly Telescope Dark Energy Experiment", The New Cosmology: Conference on Strings and Cosmology; The Mitchell Symposium on Observational Cosmology, AIP Conference Proc., 743, 2004, p.224-233

Hill, G.J., MacQueen, P.J., Palunas, P., Barnes, S.I., & Shetrone, M.D., 2008, "Present and future instrumentation for the Hobby-Eberly Telescope", Proc. SPIE, 7014, 5

Hill, G.J., Gebhardt, K., Komatsu, E., Drory, N., MacQueen, P.J., Adams, J.A., Blanc, G.A., Koehler, R., Rafal, Roth, M.M., Kelz, A., Grupp, F., Murphy, J., Palunas, P., Gronwall, C., Ciardullo, R., Bender, R., Hopp, U., and Schneider, D.P., 2008, "The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX): Description and Early Pilot Survey Results", in Panoramic Views of the Universe, ASP Conf. Series, vol 399, p 115

Jeong, D., and Komatsu, E., 2006, "Perturbation Theory Reloaded: Analytical Calculation of Nonlinearity in Baryonic Oscillations in the Real-Space Matter Power Spectrum", ApJ, 651, 619

Jeong, D., and Komatsu, E., 2009, "Perturbation Theory Reloaded. II. Nonlinear Bias, Baryon Acoustic Oscillations, and Millennium Simulation in Real Space", ApJ, 691, 569

Jeong, D., and Komatsu, E., 2010, "Primordial non-Gaussianity, scale-dependent bias, and the bispectrum of galaxies", arXiv:0904.0497

Koehler, R. S., Schuecker, P., and Gebhardt, K., 2007, "Probing dark energy with baryonic acoustic oscillations at high redshifts", A&A, 462, 7

Shoji, M., Jeong, D., and Komatsu, E., 2009, "Extracting Angular Diameter Distance and Expansion Rate of the Universe From Two-Dimensional Galaxy Power Spectrum at High Redshifts: Baryon Acoustic Oscillation Fitting Versus Full Modeling", ApJ, 693, 1404

Papers with Additional Science

Adams, J.A., Hill, G.J., and MacQueen, P.J., 2009, "B20902+34: a collapsing proto-giant elliptical galaxy at z=3.4", ApJ, 694, 314

Blanc, G., Heiderman, A., Gebhardt, K., Evans, N.J. III, Adams, J. 2009, "The Spatially Resolved Star Formation Law from Integral Field Spectroscopy: VIRUS-P Observations of NGC 5194" ApJ, arXiv:0908.2810