The non-destructive readout capability of the Skipper Charge Coupled Device (CCD) has been demonstrated to reduce the noise limitation of conventional silicon devices to levels that allow single-photon or single-electron counting. The noise reduction is achieved by taking multiple measurements of the charge in each pixel. These multiple measurements come at the cost of extra readout time, which has been a limitation for the broader adoption of this technology in particle physics, quantum imaging, and astronomy applications. This work presents recent results of a novel sensor architecture that uses multiple non-destructive floating-gate amplifiers in series to achieve sub-electron readout noise in a thick, fully-depleted silicon detector to overcome the readout time overhead of the Skipper-CCD. This sensor is called the Multiple-Amplifier Sensing Charge-Coupled Device (MAS-CCD) can perform multiple independent charge measurements with each amplifier, and the measurements from multiple amplifiers can be combined to further reduce the readout noise. We will show results obtained for sensors with 8 and 16 amplifiers per readout stage in new readout operations modes to optimize its readout speed. The noise reduction capability of the new techniques will be demonstrated in terms of its ability to reduce the noise by combining the information from the different amplifiers, and to resolve signals in the order of a single photon per pixel. The first readout operation explored here avoids the extra readout time needed in the MAS-CCD to read a line of the sensor associated with the extra extent of the serial register. The second technique explore the capability of the MAS-CCD device to perform a region of interest readout increasing the number of multiple samples per amplifier in a targeted region of the active area of the device.
Detectors with sub-electron noise open new possibilities for the spectroscopy of Earth-like exoplanets, probing the faintest signatures of dark energy and dark matter with high-redshift galaxies, and observing fast-evolving transients. Multi-amplifier sensing (MAS) charge-coupled devices (CCDs) offer the capability to achieve ultra-low readout noise floors together with a readout rate comparable to current CCDs employed in observatories. This is achieved by distributing a chain of Skipper floating-gate amplifiers along the serial register, allowing charge to be read repeatedly, non-destructively, and independently. We show recent progress in optimizing the MAS CCD for use in astronomy. These include reducing noise to sub-electron levels with faster read times than Skipper CCDs, optical characterization results, and a discussion of the range of astronomical science cases and facilities that would be enabled by MAS CCDs.
H. T. Diehl, E. Neilsen, R. Gruendl, B. Yanny, T. M. Abbott, J. Aleksić, S. Allam, J. Annis, E. Balbinot, M. Baumer, L. Beaufore, K. Bechtol, G. Bernstein, S. Birrer, C. Bonnett, D. Brout, C. Bruderer, E. Buckley-Geer, D. Capozzi, A. Carnero Rosell, F. Castander, R. Cawthon, C. Chang, L. Clerkin, R. Covarrubias, C. Cuhna, C. D'Andrea, L. da Costa, R. Das, C. Davis, J. Dietrich, A. Drlica-Wagner, A. Elliott, T. Eifler, J. Etherington, B. Flaugher, J. Frieman, A. Fausti Neto, M. Fernández, C. Furlanetto, D. Gangkofner, D. Gerdes, D. Goldstein, K. Grabowski, R. Gupta, S. Hamilton, H. Head, J. Helsby, D. Hollowood, K. Honscheid, D. James, M. Johnson, S. Jouvel, T. Kacprzac, S. Kent, R. Kessler, A. Kim, E. Krause, C. Krawiec, A. Kremin, R. Kron, S. Kuhlmann, N. Kuropatkin, O. Lahav, J. Lasker, T. Li, E. Luque, N. Maccrann, M. March, J. Marshall, N. Mondrik, E. Morganson, D. Mudd, A. Nadolski, P. Nugent, P. Melchior, F. Menanteau, D. Nagasawa, B. Nord, R. Ogando, L. Old, A. Palmese, D. Petravick, A. Plazas, A. Pujol, A. Queiroz, K. Reil, A. Romer, R. Rosenfeld, A. Roodman, P. Rooney, M. Sako, A. Salvador, C. Sánchez, E. Sánchez Álvaro, B. Santiago, A. Schooneveld, M. Schubnell, E. Sheldon, A. Smith, R. Smith, M. Soares-Santos, F. Sobreira, M. Soumagnac, H. Spinka, S. Tie, D. Tucker, V. Vikram, K. Vivas, A. Walker, W. Wester, M. Wiesner, H. Wilcox, P. Williams, A. Zenteno, Y. Zhang, Z. Zhang
The Dark Energy Survey (DES) is an operating optical survey aimed at understanding the accelerating expansion of the universe using four complementary methods: weak gravitational lensing, galaxy cluster counts, baryon acoustic oscillations, and Type Ia supernovae. To perform the 5000 sq-degree wide field and 30 sq-degree supernova surveys, the DES Collaboration built the Dark Energy Camera (DECam), a 3 square-degree, 570-Megapixel CCD camera that was installed at the prime focus of the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). DES has completed its third observing season out of a nominal five. This paper describes DES “Year 1” (Y1) to “Year 3” (Y3), the strategy, an outline of the survey operations procedures, the efficiency of operations and the causes of lost observing time. It provides details about the quality of the first three season's data, and describes how we are adjusting the survey strategy in the face of the El Niño Southern Oscillation.
Astrophysics is transforming from a data-starved to a data-swamped discipline, fundamentally changing the nature of scientific inquiry and discovery. New technologies are enabling the detection, transmission, and storage of
data of hitherto unimaginable quantity and quality across the electromagnetic, gravity and particle spectra. The
observational data obtained during this decade alone will supersede everything accumulated over the preceding
four thousand years of astronomy. Currently there are 4 large-scale photometric and spectroscopic surveys underway, each generating and/or utilizing hundreds of terabytes of data per year. Some will focus on the static
universe while others will greatly expand our knowledge of transient phenomena. Maximizing the science from
these programs requires integrating the processing pipeline with high-performance computing resources. These
are coupled to large astrophysics databases while making use of machine learning algorithms with near real-time
turnaround. Here we present an overview of one of these programs, the Palomar Transient Factory (PTF). We
will cover the processing and discovery pipeline we developed at LBNL and NERSC for it and several of the
great discoveries made during the 4 years of observations with PTF.
H. Diehl, T. M. Abbott, J. Annis, R. Armstrong, L. Baruah, A. Bermeo, G. Bernstein, E. Beynon, C. Bruderer, E. Buckley-Geer, H. Campbell, D. Capozzi, M. Carter, R. Casas, L. Clerkin, R. Covarrubias, C. Cuhna, C. D'Andrea, L. da Costa, R. Das, D. DePoy, J. Dietrich, A. Drlica-Wagner, A. Elliott, T. Eifler, J. Estrada, J. Etherington, B. Flaugher, J. Frieman, A. Fausti Neto, M. Gelman, D. Gerdes, D. Gruen, R. Gruendl, J. Hao, H. Head, J. Helsby, K. Hoffman, K. Honscheid, D. James, M. Johnson, T. Kacprzac, J. Katsaros, R. Kennedy, S. Kent, R. Kessler, A. Kim, E. Krause, R. Kron, S. Kuhlmann, A. Kunder, T. Li, H. Lin, N. Maccrann, M. March, J. Marshall, E. Neilsen, P. Nugent, P. Martini, P. Melchior, F. Menanteau, R. Nichol, B. Nord, R. Ogando, L. Old, A. Papadopoulos, K. Patton, D. Petravick, A. Plazas, R. Poulton, A. Pujol, K. Reil, T. Rigby, A. Romer, A. Roodman, P. Rooney, E. Sanchez Alvaro, S. Serrano, E. Sheldon, A. Smith, R. Smith, M. Soares-Santos, M. Soumagnac, H. Spinka, E. Suchyta, D. Tucker, A. Walker, W. Wester, M. Wiesner, H. Wilcox, R. Williams, B. Yanny, Y. Zhang
The Dark Energy Survey (DES) is a next generation optical survey aimed at understanding the accelerating expansion of the universe using four complementary methods: weak gravitational lensing, galaxy cluster counts, baryon acoustic oscillations, and Type Ia supernovae. To perform the 5000 sq-degree wide field and 30 sq-degree supernova surveys, the DES Collaboration built the Dark Energy Camera (DECam), a 3 square-degree, 570-Megapixel CCD camera that was installed at the prime focus of the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). DES started its first observing season on August 31, 2013 and observed for 105 nights through mid-February 2014. This paper describes DES “Year 1” (Y1), the strategy and goals for the first year's data, provides an outline of the operations procedures, lists the efficiency of survey operations and the causes of lost observing time, provides details about the quality of the first year's data, and hints at the “Year 2” plan and outlook.
N. Law, R. Dekany, G. Rahmer, D. Hale, R. Smith, R. Quimby, E. Ofek, M. Kasliwal, J. Zolkower, V. Velur, J. Henning, K. Bui, D. McKenna, P. Nugent, J. Jacobsen, R. Walters, J. Bloom, J. Surace, C. Grillmair, R. Laher, S. Mattingly, S. Kulkarni
The Palomar Transient Factory (PTF) is a new fully-automated, wide-field survey conducting a systematic exploration
of the optical transient sky. The transient survey is performed using a new 8.1 square degree, 101 megapixel camera
installed on the 48-inch Samuel Oschin Telescope at Palomar Observatory. The PTF Camera achieved first light at the
end of 2008, completed commissioning in July 2009, and is now in routine science operations. The camera is based on
the CFH12K camera, and was extensively modified for use on the 48-inch telescope. A field-flattening curved window
was installed, the cooling system was re-engineered and upgraded to closed-cycle, custom shutter and filter exchanger
mechanisms were added, new custom control software was written, and many other modifications were made. We here
describe the performance of these new systems during the first year of Palomar Transient Factory operations, including
a detailed and long term on-sky performance characterization. We also describe lessons learned during the construction
and commissioning of the upgraded camera, the photometric and astrometric precision currently achieved with the PTF
camera, and briefly summarize the first supernova results from the PTF survey.
P. Antilogus, R. Thomas, G. Aldering, C. Aragon, Y. Copin, E. Gangler, E. Hornero, A. Pecontal, S. Poon, K. Runge, R. Scalzo, S. Bailey, C. Baltay, C. Buton, S. Bongard, M. Childress, S. Loken, P. Nugent, R. Pain, E. Pecontal, R. Pereira, S. Perlmutter, D. Rabinowitz, G. Rigaudier, G. Smadja, C. Tao, C. Wu
Virtual Control Room allows a team of people in various locations to contribute fully to an instrument acquisition:
a reduced support is required on site but, due to the large support available off site, the data taking quality can be
still better compared to the usual on-site support scheme. The acquisition of the SNfactory spectro-photometric
follow-up is based on such data taking model. This acquisition and its performances are presented here.
Michael Sholl, Michael Lampton, Greg Aldering, W. Althouse, R. Amanullah, James Annis, Pierre Astier, Charles Baltay, E. Barrelet, Stephane Basa, Christopher Bebek, Lars Bergstrom, Gary Bernstein, Manfred Bester, Bruce Bigelow, Roger Blandford, Ralph Bohlin, Alain Bonissent, Charles Bower, Mark Brown, Myron Campbell, William Carithers, Eugene Commins, W. Craig, C. Day, F. DeJongh, Susana Deustua, T. Diehl, S. Dodelson, Anne Ealet, Richard Ellis, W. Emmet, D. Fouchez, Josh Frieman, Andrew Fruchter, D. Gerdes, L. Gladney, Gerson Goldhaber, Ariel Goobar, Donald Groom, Henry Heetderks, M. Hoff, Stephen Holland, M. Huffer, L. Hui, Dragan Huterer, B. Jain, Patrick Jelinsky, Armin Karcher, Steven Kahn, Steven Kent, Alex Kim, William Kolbe, B. Krieger, G. Kushner, N. Kuznetsova, Robin Lafever, J. Lamoureux, Olivier Le Fevre, Michael Levi, P. Limon, Huan Lin, Eric Linder, Stewart Loken, W. Lorenzon, Roger Malina, J. Marriner, P. Marshall, R. Massey, Alain Mazure, Timothy McKay, Shawn McKee, Ramon Miquel, Nicholas Morgan, E. Mörtsell, Nick Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nick Palaio, David Pankow, John Peoples, Saul Perlmutter, Eric Prieto, David Rabinowitz, Alexandre Refregier, Jason Rhodes, Natalie Roe, D. Rusin, V. Scarpine, Michael Schubnell, Gérard Smadja, Roger Smith, George Smoot, Jeffrey Snyder, Anthony Spadafora, A. Stebbins, Christopher Stoughton, Andrew Szymkowiak, Gregory Tarlé, Keith Taylor, A. Tilquin, Andrew Tomasch, Douglas Tucker, D. Vincent, Henrik von der Lippe, Jean-Pierre Walder, Guobin Wang, W. Wester
Mission requirements, the baseline design, and optical systems budgets for the SuperNova/Acceleration Probe (SNAP) telescope are presented. SNAP is a proposed space-based experiment designed to study dark energy and alternate explanations of the acceleration of the universe’s expansion by performing a series of complementary systematics-controlled astrophysical measurements. The goals of the mission are a Type Ia supernova Hubble diagram and a wide-field weak gravitational lensing survey. A 2m widefield three-mirror telescope feeds a focal plane consisting of 36 CCDs and 36 HgCdTe detectors and a high-efficiency, low resolution integral field spectrograph. Details of the maturing optical system, with emphasis on structural stability during terrestrial testing as well as expected environments during operations at L2 are discussed. The overall stray light mitigation system, including illuminated surfaces and visible objects are also presented.
Anne Ealet, Eric Prieto, Alain Bonissent, Roger Malina, Gérard Smadja, A. Tilquin, Gary Bernstein, Stephane Basa, D. Fouchez, Olivier Le Fevre, Alain Mazure, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, Manfred Bester, Roger Blandford, Ralph Bohlin, Charles Bower, Mark Brown, Myron Campbell, William Carithers, Eugene Commins, W. Craig, C. Day, F. DeJongh, Susana Deustua, H. Diehl, S. Dodelson, Richard Ellis, M. Emmet, Josh Frieman, Andrew Fruchter, D. Gerdes, L. Gladney, Gerson Goldhaber, Ariel Goobar, Donald Groom, Henry Heetderks, M. Hoff, Stephen Holland, M. Huffer, L. Hui, Dragan Huterer, B. Jain, Patrick Jelinsky, Armin Karcher, Steven Kent, Steven Kahn, Alex Kim, William Kolbe, B. Krieger, G. Kushner, N. Kuznetsova, Robin Lafever, J. Lamoureux, Michael Lampton, Michael Levi, P. Limon, Huan Lin, Eric Linder, Stewart Loken, W. Lorenzon, J. Marriner, P. Marshall, R. Massey, Timothy McKay, Shawn McKee, Ramon Miquel, Nicholas Morgan, E. Mörtsell, Nick Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nick Palaio, David Pankow, John Peoples, Saul Perlmutter, David Rabinowitz, Alexandre Refregier, Jason Rhodes, Natalie Roe, D. Rusin, V. Scarpine, Michael Schubnell, Michael Sholl, Roger Smith, George Smoot, Jeffrey Snyder, Anthony Spadafora, A. Stebbins, Christopher Stoughton, Andrew Szymkowiak, Gregory Tarlé, Keith Taylor, Andrew Tomasch, Douglas Tucker, Henrik von der Lippe, D. Vincent, Jean-Pierre Walder, Guobin Wang, W. Wester
A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Iz supernovae and to standardize the magnitude of each candidate by determining explosion parameters. The spectrograph is also a key element for the calibration of the science mission. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have high efficiency and low spectral resolution (R~100), constant through the wavelength range (0.35-1.7μm), adapted to the scientific goals of the mission.
Michael Lampton, Michael Sholl, Michael Krim, R. Besuner, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, Charles Baltay, E. Barrelet, Stephane Basa, Christopher Bebek, John Bercovitz, Lars Bergstrom, Gary Berstein, Manfred Bester, Ralph Bohlin, Alain Bonissent, Charles Bower, Myron Campbell, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, William Emmett, Mikael Eriksson, D. Fouchez, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Henry Heetderks, Stephen Holland, Dragan Huterer, William Johnston, Richard Kadel, Armin Karcher, Alex Kim, William Kolbe, Robin Lafever, J. Lamoureux, Oliver LeFevre, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, Alain Mazure, Timothy McKay, Shawn McKee, Ramon Miquel, Nicholas Morgan, E. Mortsell, Nick Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nick Palaio, David Pankow, Saul Perlmutter, Eric Prieto, David Rabinowitz, Alexandre Refregier, Jason Rhodes, Natalie Roe, Michael Schubnell, G. Smadja, R. Smith, George Smoot, Jeffrey Snyder, Anthony Spadafora, Andrew Szymkowiak, Gregory Tarle, Keith Taylor, A. Tilquin, Andrew Tomasch, D. Vincent, Henrik von der Lippe, Jean-Pierre Walder, Guobin Wang
We present the baseline telescope design for the telescope for the SuperNova/Acceleration Probe (SNAP) space mission. SNAP’s purpose is to determine expansion history of the Universe by measuring the redshifts, magnitudes, and spectral classifications of thousands of supernovae with unprecedented accuracy. Discovering and measuring these supernovae demand both a wide optical field and a high sensitivity throughout the visible and near IR wavebands. We have adopted the annular-field three-mirror anastigmat (TMA) telescope configuration, whose classical aberrations (including chromatic) are zero. We show a preliminary optmechanical design that includes important features for stray light control and on-orbit adjustment and alignment of the optics. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of the design tasks being carried out during the current SNAP research and development phase.
Christopher Bebek, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, Charles Baltay, E. Barrelet, Stephane Basa, John Bercovitz, Lars Bergstrom, Gary Berstein, Manfred Bester, Ralph Bohlin, Alain Bonissent, Charles Bower, Myron Campbell, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, William Emmett, Mikael Eriksson, D. Fouchez, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Henry Heetderks, Stephen Holland, Dragan Huterer, William Johnston, Richard Kadel, Armin Karcher, Alex Kim, William Kolbe, Robin Lafever, J. Lamoureux, Michael Lampton, Oliver LeFevre, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, Alain Mazure, Timothy McKay, Shawn McKee, Ramon Miquel, Nicholas Morgan, E. Mortsell, N. Mostek, Stuart Mufson, J. Musser, Natalie Roe, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, Eric Prieto, David Rabinowitz, Alexandre Refregier, Jason Rhodes, Michael Schubnell, Michael Sholl, G. Smadja, R. Smith, George Smoot, Jeffrey Snyder, Anthony Spadafora, Andrew Szymkowiak, Gregory Tarle, Keith Taylor, A. Tilquin, Andrew Tomasch, D. Vincent, Henrik von der Lippe, Jean-Pierre Walder, Guobin Wang
The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to advance our preparedness for mission proposal in the areas of detectors and electronics.
Anne Ealet, Eric Prieto, Alain Bonissent, Roger Malina, G. Bernstein, Stephane Basa, Oliver LeFevre, Alain Mazure, Christophe Bonneville, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, John Bercovitz, Manfred Bester, C. Bower, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, R. Ellis, Mikael Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, Alex Kim, William Kolbe, B. Krieger, R. Lafever, J. Lamoureux, Michael Lampton, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, R. Massey, Timothy McKay, Shawn McKee, Ramon Miquel, E. Moertsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Alexandre Refregier, J. Rhodes, Kem Robinson, N. Roe, Michael Sholl, Michael Schubnell, G. Smadja, George Smoot, Anthony Spadafora, Gregory Tarle, Andrew Tomasch, H. von der Lippe, D. Vincent, J.-P. Walder, Guobin Wang
A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R~100), constant through the wavelength range (0.35-1.7μm), adapted to the scientific goals of the mission.
Gregory Tarle, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, John Bercovitz, Gary Bernstein, Manfred Bester, Alain Bonissent, C. Bower, Mark Brown, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, Mikael Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, Alex Kim, William Kolbe, B. Krieger, R. Lafever, J. Lamoureux, Michael Lampton, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, R. Massey, Ramon Miquel, Timothy McKay, Shawn McKee, E. Moertsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Eric Prieto, Alexandre Refregier, Jason Rhodes, Kem Robinson, N. Roe, Michael Schubnell, Michael Sholl, G. Smadja, George Smoot, Anthony Spadafora, Andrew Tomasch, D. Vincent, H. von der Lippe, J.-P. Walder, Guobin Wang
The SuperNova/Acceleration Probe (SNAP) will measure precisely the cosmological expansion history over both the acceleration and deceleration epochs and thereby constrain the nature of the dark energy that dominates our universe today. The SNAP focal plane contains equal areas of optical CCDs and NIR sensors and an integral field spectrograph. Having over 150 million pixels and a field-of-view of 0.34 square degrees, the SNAP NIR system will be the largest yet constructed. With sensitivity in the range 0.9-1.7 μm, it will detect Type Ia supernovae between z = 1 and 1.7 and will provide follow-up precision photometry for all supernovae. HgCdTe technology, with a cut-off tuned to 1.7 μm, will permit passive cooling at 140 K while maintaining noise below zodiacal levels. By dithering to remove the effects of intrapixel variations and by careful attention to other instrumental effects, we expect to control relative photometric accuracy below a few hundredths of a magnitude. Because SNAP continuously revisits the same fields we will be able to achieve outstanding statistical precision on the photometry of reference stars in these fields, allowing precise monitoring of our detectors. The capabilities of the NIR system for broadening the science reach of SNAP are discussed.
Michael Lampton, Christopher Bebek, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Lars Bergstrom, John Bercovitz, Gary Bernstein, Manfred Bester, Alain Bonissent, C. Bower, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, Mikael Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, Alex Kim, William Kolbe, B. Krieger, R. Lafever, J. Lamoureux, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, R. Massey, Timothy McKay, Steven McKee, Ramon Miquel, E. Moertsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Eric Prieto, Alexandre Refregier, J. Rhodes, Kem Robinson, N. Roe, Michael Sholl, Michael Schubnell, G. Smadja, George Smoot, Anthony Spadafora, Gregory Tarle, Andrew Tomasch, H. von der Lippe, D. Vincent, J.-P. Walder, Guobin Wang
The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square-degree field sensitive in the visible and near-infrared wavelength regime. We describe the requirements for the instrument suite and the evolution of the focal plane design to the present concept in which all the instrumentation -- visible and near-infrared imagers, spectrograph, and star guiders -- share one common focal plane.
Alex Kim, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, J. Bercovitz, Gary Bernstein, M. Bester, A. Bonissent, C. Bower, William Carithers, Eugene Commins, C. Day, Susana Deustua, R. DiGennaro, A. Ealet, Richard Ellis, M. Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, William Kolbe, B. Krieger, Robin Lafever, J. Lamoureux, Michael Lampton, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, R. Massey, Timothy McKay, Shawn McKee, Ramon Miquel, E. Mortsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Eric Prieto, Alexandre Refregier, Jason Rhodes, Kem Robinson, N. Roe, Michael Sholl, Michael Schubnell, G. Smadja, George Smoot, Anthony Spadafora, Gregory Tarle, Andrew Tomasch, H. von der Lippe, D. Vincent, J.-P. Walder, Guobin Wang
The Supernova / Acceleration Probe (SNAP) is a proposed space-borne observatory that will survey the sky with a wide-field optical/near-infrared (NIR) imager. The images produced by SNAP will have an unprecedented combination of depth, solid-angle, angular resolution, and temporal sampling. For 16 months each, two 7.5 square-degree fields will be observed every four days to a magnitude depth of AB=27.7 in each of the SNAP filters, spanning 3500-17000Å. Co-adding images over all epochs will give AB=30.3 per filter. In addition, a 300 square-degree field will be surveyed to AB=28 per filter, with no repeated temporal sampling. Although the survey strategy is tailored for supernova and weak gravitational lensing observations, the resulting data will support a broad range of auxiliary science programs.
Greg Aldering, G. Adam, P. Antilogus, Pierre Astier, R. Bacon, S. Bongard, C. Bonnaud, Y. Copin, Delphine Hardin, Francois Henault, Dale Howell, Jean-Pierre Lemonnier, Jean-Michel Levy, Stewart Loken, Peter Nugent, Reynald Pain, A. Pecontal, E. Pecontal, Saul Perlmutter, Robert Quimby, K. Schahmaneche, G. Smadja, W. Michael Wood-Vasey
The Nearby Supernova Factory (Snfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The Snfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000Å for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the Snfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The Snfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.
Michael Lampton, Carl Akerlof, Greg Aldering, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, John Bercovitz, G. Bernstein, Manfred Bester, Alain Bonissent, C. Bower, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, Mikael Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, Alex Kim, William Kolbe, B. Krieger, R. Lafever, J. Lamoureux, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, R. Massey, Timothy McKay, Shawn McKee, Ramon Miquel, E. Mortsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Eric Prieto, Alexandre Refregier, J. Rhodes, Kem Robinson, N. Roe, Michael Sholl, Michael Schubnell, G. Smadja, George Smoot, A. Spadafora, Gregory Tarle, Andrew Tomasch, H. von der Lippe, R. Vincent, J.-P. Walder, Guobin Wang
The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.
Greg Aldering, Carl Akerlof, R. Amanullah, Pierre Astier, E. Barrelet, Christopher Bebek, Lars Bergstrom, John Bercovitz, Gary Bernstein, Manfred Bester, Alain Bonissent, Charles Bower, William Carithers, Eugene Commins, C. Day, Susana Deustua, Richard DiGennaro, Anne Ealet, Richard Ellis, Mikael Eriksson, Andrew Fruchter, Jean-Francois Genat, Gerson Goldhaber, Ariel Goobar, Donald Groom, Stewart Harris, Peter Harvey, Henry Heetderks, Steven Holland, Dragan Huterer, Armin Karcher, Alex Kim, William Kolbe, B. Krieger, R. Lafever, James Lamoreux, Michael Lampton, Michael Levi, Daniel Levin, Eric Linder, Stewart Loken, Roger Malina, R. Massey, Timothy McKay, Shawn McKee, Ramon Miquel, E. Moertsell, N. Mostek, Stuart Mufson, J. Musser, Peter Nugent, Hakeem Oluseyi, Reynald Pain, Nicholas Palaio, David Pankow, Saul Perlmutter, R. Pratt, Eric Prieto, Alexandre Refregier, J. Rhodes, Kem Robinson, N. Roe, Michael Sholl, Michael Schubnell, G. Smadja, George Smoot, Anthony Spadafora, Gregory Tarle, Andrew Tomasch, H. von der Lippe, D. Vincent, J.-P. Walder, Guobin Wang
The SuperNova / Acceleration Probe (SNAP) is a space-based experiment to measure the expansion history of the Universe and study both its dark energy and the dark matter. The experiment is motivated by the startling discovery that the expansion of the Universe is accelerating. A 0.7~square-degree imager comprised of 36 large format fully-depleted n-type CCD's sharing a focal plane with 36 HgCdTe detectors forms the heart of SNAP, allowing discovery and lightcurve measurements simultaneously for many supernovae. The imager and a high-efficiency low-resolution integral field spectrograph are coupled to a 2-m three mirror anastigmat wide-field telescope, which will be placed in a high-earth orbit. The SNAP mission can obtain high-signal-to-noise calibrated light-curves and spectra for over 2000 Type Ia supernovae at redshifts between z = 0.1 and 1.7. The resulting data set can not only determine the amount of dark energy with high precision, but test the nature of the dark energy by examining its equation of state. In particular, dark energy due to a cosmological constant can be differentiated from alternatives such as "quintessence", by measuring the dark energy's equation of state to an accuracy of ± 0.05, and by studying its time dependence.
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