GammeV: a milli-eV particle search at Fermilab

W. Wester

GammeV is an experiment conducted at Fermilab that employs the light shining through a wall technique to search for axion-like particles and employs a particle in a jar technique to search for dilaton-like chameleon particles. We obtain limits on the coupling of photons to an axion-like particle that extend previous limits for both scalars and pseudoscalars in the milli-eV mass range. We are able to exclude the axion-like particle interpretation of the anomalous PVLAS 2006 result by more than 5 standard deviations. We also present results on a search for chameleons and set limits on their possible coupling to photons.

Candidate Massive Galaxies at $z \sim 4$ in the Dark Energy Survey

Pierandrea Guarnieri, Claudia Maraston, Daniel Thomas, Janine Pforr, Violeta Gonzalez-Perez, James Etherington, Joakim Carlsen, Xan Morice-Atkinson, Christopher J. Conselice, Julia Gschwend, Matias Carrasco Kind, Tim Abbott, Sahar Allam, David Brooks, David Burke, Aurelio Carnero Rosell, Jorge Carretero, Carlos Cunha, Chris ďAndrea, Luiz da Costa, Juan De Vincente, Darren DePoy, H. Thomas Diehl, Peter Doel, Josh Frieman, Juan Garcia-Bellido, Daniel Gruen, Gaston Gutierrez, Dominic Hanley, Devon Hollowood, Klaus Honscheid, David James, Tesla Jeltema, Kyler Kuehn, Marcos Lima, Marcio A. G. Maia, Jennifer Marshall, Paul Martini, Peter Melchior, Felipe Menanteau, Ramon Miquel, Andres Plazas Malagon, Samuel Richardson, Kathy Romer, Eusebio Sanchez, Vic Scarpine, Rafe Schindler, Ignacio Sevilla, Mathew Smith, Marcelle Soares-Santos, Flavia Sobreira, Eric Suchyta, Gregory Tarle, Alistair Walker, William Wester

Using stellar population models, we predicted that the Dark Energy Survey (DES) - due to its special combination of area (5000 deg. sq.) and depth ($i = 24.3$) - would be in the position to detect massive ($\gtrsim 10^{11}$ M$_{\odot}$) galaxies at $z \sim 4$. We confront those theoretical calculations with the first $\sim 150$ deg. sq. of DES data reaching nominal depth. From a catalogue containing $\sim 5$ million sources, $\sim26000$ were found to have observed-frame $g-r$ vs $r-i$ colours within the locus predicted for $z \sim 4$ massive galaxies. We further removed contamination by stars and artefacts, obtaining 606 galaxies lining up by the model selection box. We obtained their photometric redshifts and physical properties by fitting model templates spanning a wide range of star formation histories, reddening and redshift. Key to constrain the models is the addition, to the optical DES bands $g$, $r$, $i$, $z$, and $Y$, of near-IR $J$, $H$, $K_{s}$ data from the Vista Hemisphere Survey. We further applied several quality cuts to the fitting results, including goodness of fit and a unimodal redshift probability distribution. We finally select 233 candidates whose photometric redshift probability distribution function peaks around $z\sim4$, have high stellar masses ($\log($M$^{*}$/M$_{\odot})\sim 11.7$ for a Salpeter IMF) and ages around 0.1 Gyr, i.e. formation redshift around 5. These properties match those of the progenitors of the most massive galaxies in the local universe. This is an ideal sample for spectroscopic follow-up to select the fraction of galaxies which is truly at high redshift. These initial results and those at the survey completion, which we shall push to higher redshifts, will set unprecedented constraints on galaxy formation, evolution, and the re-ionisation epoch.

Design for the First Narrowband Filter for the Dark Energy Camera: Optimizing the LAGER Survey for z ~ 7 Galaxies

Zhen-Ya Zheng, James E. Rhoads, Junxian Wang, Sangeeta Malhotra, Alistair Walker, Thomas Mooney, Chunyan Jiang, Weida Hu, Pascale Hibon, Linhua Jiang, Leopoldo Infante, L. Felipe Barrientos, Gaspar Galaz, Francisco Valdes, William Wester, Huan Yang, Alicia Coughlin, Santosh Harish, Wenyong Kang, Ali Ahmad Khostovan, Xu Kong, Lucia A. Perez, John Pharo, Isak Wold, XianZhong Zheng

We present the design for the first narrowband filter NB964 for the Dark Energy Camera (DECam), which is operated on the 4m Blanco Telescope at the Cerro Tololo Inter-American Observatory. The NB964 filter profile is essentially defined by maximizing the power of searching for Lyman alpha emitting galaxies (LAEs) in the epoch of reionization, with the consideration of the night sky background in the near-infrared and the DECam quantum efficiency. The NB964 filter was manufactured by Materion in 2015. It has a central wavelength of 964.2 nm and a full width at half maximum (FWHM) of 9.2 nm. An NB964 survey named LAGER (Lyman Alpha Galaxies in the Epoch of Reionization) has been ongoing since December 2015. Here we report results of lab tests, on-site tests and observations with the NB964 filter. The excellent performances of this filter ensure that the LAGER project is able to detect LAEs at z~7 with a high efficiency.

Host Galaxy Identification for Supernova Surveys

Ravi R. Gupta, Steve Kuhlmann, Eve Kovacs, Harold Spinka, Richard Kessler, Daniel A. Goldstein, Camille Liotine, Katarzyna Pomian, Chris B. D'Andrea, Mark Sullivan, Jorge Carretero, Francisco J. Castander, Robert C. Nichol, David A. Finley, John A. Fischer, Ryan J. Foley, Alex G. Kim, Andreas Papadopoulos, Masao Sako, Daniel M. Scolnic, Mathew Smith, Brad E. Tucker, Syed Uddin, Rachel C. Wolf, Fang Yuan, Tim M. C. Abbott, Filipe B. Abdalla, Aurelien Benoit-Levy, Emmanuel Bertin, David Brooks, Aurelio Carnero Rosell, Matias Carrasco Kind, Carlos E. Cunha, Luiz N. da Costa, Shantanu Desai, Peter Doel, Tim F. Eifler, August E. Evrard, Brenna Flaugher, Pablo Fosalba, Enrique Gaztanaga, Daniel Gruen, Robert Gruendl, David J. James, Kyler Kuehn, Nikolay Kuropatkin, Marcio A. G. Maia, Jennifer L. Marshall, Ramon Miquel, Andres A. Plazas, A. Kathy Romer, Eusebio Sanchez, Michael Schubnell, Ignacio Sevilla-Noarbe, Flavia Sobreira, Eric Suchyta, Molly E. C. Swanson, Gregory Tarle, Alistair R. Walker, William Wester

Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST), which will discover SNe by the thousands. Spectroscopic resources are limited, so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

Marco Battaglieri, Alberto Belloni, Aaron Chou, Priscilla Cushman, Bertrand Echenard, Rouven Essig, Juan Estrada, Jonathan L. Feng, Brenna Flaugher, Patrick J. Fox, Peter Graham, Carter Hall, Roni Harnik, JoAnne Hewett, Joseph Incandela, Eder Izaguirre, Daniel McKinsey, Matthew Pyle, Natalie Roe, Gray Rybka, Pierre Sikivie, Tim M. P. Tait, Natalia Toro, Richard Van De Water, Neal Weiner, Kathryn Zurek, Eric Adelberger, Andrei Afanasev, Derbin Alexander, James Alexander, Vasile Cristian Antochi, David Mark Asner, Howard Baer, Dipanwita Banerjee, Elisabetta Baracchini, Phillip Barbeau, Joshua Barrow, Noemie Bastidon, James Battat, Stephen Benson, Asher Berlin, Mark Bird, Nikita Blinov, Kimberly K. Boddy, Mariangela Bondi, Walter M. Bonivento, Mark Boulay, James Boyce, Maxime Brodeur, Leah Broussard, Ranny Budnik, Philip Bunting, Marc Caffee, Sabato Stefano Caiazza, Sheldon Campbell, Tongtong Cao, Gianpaolo Carosi, Massimo Carpinelli, Gianluca Cavoto, Andrea Celentano, Jae Hyeok Chang, Swapan Chattopadhyay, Alvaro Chavarria, Chien-Yi Chen, Kenneth Clark, John Clarke, Owen Colegrove, Jonathon Coleman, David Cooke, Robert Cooper, Michael Crisler, Paolo Crivelli, Francesco D'Eramo, Domenico D'Urso, Eric Dahl, William Dawson, Marzio De Napoli, Raffaella De Vita, Patrick DeNiverville, Stephen Derenzo, Antonia Di Crescenzo, Emanuele Di Marco, Keith R. Dienes, Milind Diwan, Dongwi Handiipondola Dongwi, Alex Drlica-Wagner, Sebastian Ellis, Anthony Chigbo Ezeribe, Glennys Farrar, Francesc Ferrer, Enectali Figueroa-Feliciano, Alessandra Filippi, Giuliana Fiorillo, Bartosz Fornal, Arne Freyberger, Claudia Frugiuele, Cristian Galbiati, Iftah Galon, Susan Gardner, Andrew Geraci, Gilles Gerbier, Mathew Graham, Edda Gschwendtner, Christopher Hearty, Jaret Heise, Reyco Henning, Richard J. Hill, David Hitlin, Yonit Hochberg, Jason Hogan, Maurik Holtrop, Ziqing Hong, Todd Hossbach, T. B. Humensky, Philip Ilten, Kent Irwin, John Jaros, Robert Johnson, Matthew Jones, Yonatan Kahn, Narbe Kalantarians, Manoj Kaplinghat, Rakshya Khatiwada, Simon Knapen, Michael Kohl, Chris Kouvaris, Jonathan Kozaczuk, Gordan Krnjaic, Valery Kubarovsky, Eric Kuflik, Alexander Kusenko, Rafael Lang, Kyle Leach, Tongyan Lin, Mariangela Lisanti, Jing Liu, Kun Liu, Ming Liu, Dinesh Loomba, Joseph Lykken, Katherine Mack, Jeremiah Mans, Humphrey Maris, Thomas Markiewicz, Luca Marsicano, C. J. Martoff, Giovanni Mazzitelli, Christopher McCabe, Samuel D. McDermott, Art McDonald, Bryan McKinnon, Dongming Mei, Tom Melia, Gerald A. Miller, Kentaro Miuchi, Sahara Mohammed Prem Nazeer, Omar Moreno, Vasiliy Morozov, Frederic Mouton, Holger Mueller, Alexander Murphy, Russell Neilson, Tim Nelson, Christopher Neu, Yuri Nosochkov, Ciaran O'Hare, Noah Oblath, John Orrell, Jonathan Ouellet, Saori Pastore, Sebouh Paul, Maxim Perelstein, Annika Peter, Nguyen Phan, Nan Phinney, Michael Pivovaroff, Andrea Pocar, Maxim Pospelov, Josef Pradler, Paolo Privitera, Stefano Profumo, Mauro Raggi, Surjeet Rajendran, Nunzio Randazzo, Tor Raubenheimer, Christian Regenfus, Andrew Renshaw, Adam Ritz, Thomas Rizzo, Leslie Rosenberg, Andre Rubbia, Ben Rybolt, Tarek Saab, Benjamin R. Safdi, Elena Santopinto, Andrew Scarff, Michael Schneider, Philip Schuster, George Seidel, Hiroyuki Sekiya, Ilsoo Seong, Gabriele Simi, Valeria Sipala, Tracy Slatyer, Oren Slone, Peter F Smith, Jordan Smolinsky, Daniel Snowden-Ifft, Matthew Solt, Andrew Sonnenschein, Peter Sorensen, Neil Spooner, Brijesh Srivastava, Ion Stancu, Louis Strigari, Jan Strube, Alexander O. Sushkov, Matthew Szydagis, Philip Tanedo, David Tanner, Rex Tayloe, William Terrano, Jesse Thaler, Brooks Thomas, Brianna Thorpe, Thomas Thorpe, Javier Tiffenberg, Nhan Tran, Marco Trovato, Christopher Tully, Tony Tyson, Tanmay Vachaspati, Sven Vahsen, Karl van Bibber, Justin Vandenbroucke, Anthony Villano, Tomer Volansky, Guojian Wang, Thomas Ward, William Wester, Andrew Whitbeck, David A. Williams, Matthew Wing, Lindley Winslow, Bogdan Wojtsekhowski, Hai-Bo Yu, Shin-Shan Yu, Tien-Tien Yu, Xilin Zhang, Yue Zhao, Yi-Ming Zhong

Discovery of a New Quasar: SDSS J022155.26-064916.6

Jacob M. Robertson, Douglas L. Tucker, J. Allyn Smith, William Wester, Haun Lin, Jack H. Mueller, Deborah J. Gulledge

We report the discovery of a new quasar: SDSS J022155.26-064916.6. This object was discovered while reducing spectra of a sample of stars being considered as spectrophotometric standards for the Dark Energy Survey. The flux and wavelength calibrated spectrum is presented with four spectral lines identified. From these lines, the redshift is determined to be z is approximately equal to 0.806. In addition, the rest-frame u-, g-, and r-band luminosity, determined using a k-correction obtained with synthetic photometry of a proxy QSO, are reported as 7.496 $\times 10^{13}$ solar luminosities, 2.049 $\times 10^{13}$ solar luminosities, and $1.896 \times 10^{13}$ solar luminosities, respectively.

Extreme variability quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

Nick Rumbaugh, Yue Shen, Eric Morganson, Xin Liu, Manda Banerji, Richard G. McMahon, Filipe Abdalla, Aurelien Benoit-Levy, Emmanuel Bertin, David Brooks, Elizabeth Buckley-Geer, Diego Capozzi, Aurelio Carnero Rosell, M. Carrasco Kind, Jorge Carretero, Carlos Cunha, Chris D'Andrea, Luiz da Costa, Darren DePoy, Shantanu Desai, Peter Doel, Joshua Frieman, Juan Garcia-Bellido, Daniel Gruen, Robert Gruendl, Julia Gschwend, Gaston Gutierrez, Klaus Honscheid, David James, Kyler Kuehn, Steve Kuhlmann, Nikolay Kuropatkin, Marcos Lima, Marcio Maia, Jennifer Marshall, Paul Martini, Felipe Menanteau, Andres Plazas Malagon, Kevin Reil, Aaron Roodman, Eusebio Sanchez, Vic Scarpine, Rafe Schindler, Michael Schubnell, Erin Sheldon, Mathew Smith, Marcelle Soares-Santos, Flavia Sobreira, Eric Suchyta, Molly Swanson, Alistair Walker, William Wester

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L_bol~10^45-10^47 erg/s and L/L_Edd~0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30-50% among all g<~22 quasars over a baseline of ~15 years. These EVQs are good candidates for so-called "changing-look quasars", where a spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales.

Astrometry and Occultation predictions to Trans-Neptunian and Centaur Objects observed within the Dark Energy Survey

Martin Banda-Huarca, Julio Camargo, Josselin Desmars, Ricardo Ogando, Roberto Vieira-Martins, Marcelo Assafin, Luiz da Costa, Gary Bernstein, Matias Carrasco Kind, Alex Drlica Wagner, Rodney Gomes, Matheus Gysi, Felipe Braga Ribas, Marcio Maia, David Gerdes, Stephanie Hamilton, William Wester, Tim Abbot, Filipe Abdalla, Sahar Allam, Santiago Avila, Emmanuel Bertin, David Brooks, Elizabeth Buckley-Geer, David Burke, Aurelio Carnero Rossell, Jorge Carretero, Carlos Cunha, Christopher Davis, Juan de Vicente, Thomas Diehl, Peter Doel, Pablo Fosalba, Josh Frieman, Juan Garcia-Bellido, Enrique Gaztanaga, Daniel Gruen, Robert Gruendl, Julia Gschwend, Gaston Gutierrez, Will Hartley, Devon Hollowood, Klaus Honscheid, David James, Kyler Kuehn, Nikolay Kuropatkin, Felipe Menanteau, Christopher Miller, Ramon Miquel, Andres Plazas, Kathy Romer, Eusebio Sanchez, Vic Scarpine, Michael Schubnell, Santiago Serrano, Ignacio Sevilla, Mathew Smith, Marcelle Soares-Santos, Flavia Sobreira, Eric Suchyta, Molly Swanson, Gregory Tarle

Transneptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and the Gaia space mission, a new exciting era is within reach as accurate predictions of stellar occultations by numerous distant small solar system bodies become available. From them, diameters with kilometer accuracies can be determined. Albedos, in turn, can be obtained from diameters and absolute magnitudes. We use observations from the Dark Energy Survey (DES) from November 2012 until February 2016, amounting to 4292847 CCD frames. We searched them for all known small solar system bodies and recovered a total of 202 TNOs and Centaurs, 63 of which have been discovered by the DES collaboration until the date of this writing. Their positions were determined using the Gaia Data Release 2 as reference and their orbits were refined. Stellar occultations were then predicted using these refined orbits plus stellar positions from Gaia. These predictions are maintained, and updated, in a dedicated web service. The techniques developed here are also part of an ambitious preparation to use the data from the Large Synoptic Survey Telescope (LSST), that expects to obtain accurate positions and multifilter photometry for tens of thousands of TNOs.

Discovery of a New Blue Quasar: SDSS J022218.03-062511.1

Mees B. Fix, J. Allyn Smith, Douglas L. Tucker, William Wester, James Annis

We report the discovery of a bright blue quasar: SDSS J022218.03-062511.1. This object was discovered spectroscopically while searching for hot white dwarfs that may be used as calibration sources for large sky surveys such as the Dark Energy Survey or the Large Synoptic Survey Telescope project. We present the calibrated spectrum, spectral line shifts and report a redshift of z = 0.521 +/- 0.0015 and a rest-frame g-band luminosity of 8.71 X 10^11 L(Sun).

Laboratory constraints on chameleon dark energy and power-law fields

Jason H. Steffen, Amol Upadhye, Al Baumbaugh, Aaron S. Chou, Peter O. Mazur, Ray Tomlin, Amanda Weltman, William Wester

We report results from the GammeV Chameleon Afterglow Search---a search for chameleon particles created via photon/chameleon oscillations within a magnetic field. This experiment is sensitive to a wide class of chameleon power-law models and dark energy models not previously explored. These results exclude five orders of magnitude in the coupling of chameleons to photons covering a range of four orders of magnitude in chameleon effective mass and, for individual chameleon models, exclude between 4 and 12 orders of magnitude in chameleon couplings to matter.

A Rich Tapestry: Supersymmetric Axions, Dark Radiation, and Inflationary Reheating

Farinaldo S. Queiroz, Kuver Sinha, William Wester

We exploit the complementarity among supersymmetry, inflation, axions, Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background Radiation (CMB) to constrain supersymmetric axion models in the light of the recent Planck and BICEP results. In particular, we derive BBN bounds coming from altering the light element abundances by taking into account hadronic and electromagnetic energy injection, and CMB constraints from black-body spectrum distortion. Lastly, we outline the viable versus excluded region of these supersymetric models that might account for the mild dark radiation observed.

OzDES Reverberation Mapping Program: Lag recovery reliability for 6-year CIV analysis

Andrew Penton, Umang Malik, Tamara Davis, Paul Martini, Zhefu Yu, Rob Sharp, Christopher Lidman, Brad E. Tucker, Janie Hoormann, Michel Aguena, Sahar Allam, James Annis, Jacobo Asorey, David Bacon, Emmanuel Bertin, Sunayana Bhargava, David Brooks, Josh Calcino, Aurelio Carnero Rosell, Daniela Carollo, Matias Carrasco Kind, Jorge Carretero, Matteo Costanzi, Luiz da Costa, Maria Elidaiana da Silva Pereira, Juan De Vicente, H. Thomas Diehl, Tim Eifler, Spencer Everett, Ismael Ferrero, Pablo Fosalba, Josh Frieman, Juan Garcia-Bellido, Enrique Gaztanaga, David Gerdes, Daniel Gruen, Robert Gruendl, Julia Gschwend, Gaston Gutierrez, Samuel Hinton, Devon L. Hollowood, Klaus Honscheid, David James, Alex Kim, Kyler Kuehn, Nikolay Kuropatkin, Marcio Maia, Jennifer Marshall, Felipe Menanteau, Ramon Miquel, Anais Möller, Robert Morgan, Antonella Palmese, Francisco Paz-Chinchon, Andrés Plazas Malagón, Kathy Romer, Eusebio Sanchez, Vic Scarpine, Daniel Scolnic, Santiago Serrano, Mathew Smith, Eric Suchyta, Molly Swanson, Gregory Tarle, Chun-Hao To, Syed Uddin, Tamas Norbert Varga, William Wester, Reese Wilkinson

We present the statistical methods that have been developed to analyse the OzDES reverberation mapping sample. To perform this statistical analysis we have created a suite of customisable simulations that mimic the characteristics of each source in the OzDES sample. These characteristics include: the variability in the photometric and spectroscopic lightcurves, the measurement uncertainties, and the observational cadence. By simulating the sources in the OzDES sample that contain the CIV emission line, we developed a set of criteria that rank the reliability of a recovered time lag depending on the agreement between different recovery methods, the magnitude of the uncertainties, and the rate at which false positives were found in the simulations. These criteria were applied to simulated light curves and these results used to estimate the quality of the resulting Radius-Luminosity relation.We grade the results using three quality levels (gold, silver and bronze). The input slope of the R-L relation was recovered within $1σ$ for each of the three quality samples, with the gold standard having the lowest dispersion with a recovered a R-L relation slope of $0.454\pm 0.016$ with an input slope of 0.47. Future work will apply these methods to the entire OzDES sample of 771 AGN.

Measuring the flatness of focal plane for very large mosaic CCD camera

Jiangang Hao, Juan Estrada, Herman Cease, H. Thomas Diehl, Brenna L. Flaugher, Donna Kubik, Keivin Kuk, Nickolai Kuropatkine, Huan Lin, Jorge Montes, Vic Scarpine, Ken Schultz, William Wester

Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k$\times$2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 years starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. Simulation and real measurements show that the two methods work very well for our purpose, and are in good agreement with the direct optical measurements.

Discovery and Physical Characterization of a Large Scattered Disk Object at 92 AU

David Gerdes, Masao Sako, Stephanie Hamilton, Ke Zhang, Tali Khain, Juliette Becker, James Annis, William Wester, Gary Bernstein, Colin Scheibner, Lynus Zullo, Fred Adams, Edwin Bergin, Alistair Walker, J. H. Mueller, T. Abbott, Filipe Abdalla, Sahar Allam, K. Bechtol, Aurelien Benoit-Lévy, Emmanuel Bertin, David Brooks, David Burke, A. Rosell, M. Kind, Jorge Carretero, Carlos Cunha, Luiz da Costa, S. Desai, H. Thomas Diehl, Tim Eifler, Brenna Flaugher, Joshua Frieman, J. Garc'ia-Bellido, Enrique Gaztanaga, Daniel Goldstein, Daniel Gruen, J. Gschwend, Gaston Gutierrez, Klaus Honscheid, D. James, Stephen M. Kent, E. Krause, Kyler Kuehn, Nikolay Kuropatkin, O. Lahav, T. Li, M. Maia, Marisa Cristina March, Jennifer Marshall, P. Martini, Felipe Menanteau, Ramon Miquel, Robert Nichol, Andres Plazas Malagón, A. Kathy Romer, Aaron Roodman, Eusebio Sanchez, Ignacio Sevilla-Noarbe, Mathew Smith, R. Smith, Marcelle Soares-Santos, Flavia Sobreira, E. Suchyta, M. Swanson, Gregory Tarle, Douglas Tucker, Y. Zhang

We report the observation and physical characterization of the possible dwarf planet \UZ\ ("DeeDee"), a dynamically detached trans-Neptunian object discovered at 92 AU. This object is currently the second-most distant known trans-Neptunian object with reported orbital elements, surpassed in distance only by the dwarf planet Eris. The object was discovered with an $r$-band magnitude of 23.0 in data collected by the Dark Energy Survey between 2014 and 2016. Its 1140-year orbit has $(a,e,i) = (109~\mathrm{AU}, 0.65, 26.8^{\circ})$. It will reach its perihelion distance of 38 AU in the year 2142. Integrations of its orbit show it to be dynamically stable on Gyr timescales, with only weak interactions with Neptune. We have performed followup observations with ALMA, using 3 hours of on-source integration time to measure the object's thermal emission in the Rayleigh-Jeans tail. The signal is detected at 7$σ$ significance, from which we determine a $V$-band albedo of $13.1^{+3.3}_{-2.4}\mathrm{(stat)}^{+2.0}_{-1.4}\mathrm{(sys)}$ percent and a diameter of $635^{+57}_{-61}\mathrm{(stat)}^{+32}_{-39}\mathrm{(sys)}$~km, assuming a spherical body with uniform surface properties.

Double machine learning to estimate the effects of multiple treatments and their interactions

Qingyan Xiang, Yubai Yuan, Dongyuan Song, Usman J. Wudil, Muktar H. Aliyu, C. William Wester, Bryan E. Shepherd

Causal inference literature has extensively focused on binary treatments, with relatively fewer methods developed for multi-valued treatments. In particular, methods for multiple simultaneously assigned treatments remain understudied despite their practical importance. This paper introduces two settings: (1) estimating the effects of multiple treatments of different types (binary, categorical, and continuous) and the effects of treatment interactions, and (2) estimating the average treatment effect across categories of multi-valued regimens. To obtain robust estimates for both settings, we propose a class of methods based on the Double Machine Learning (DML) framework. Our methods are well-suited for complex settings of multiple treatments/regimens, using machine learning to model confounding relationships while overcoming regularization and overfitting biases through Neyman orthogonality and cross-fitting. To our knowledge, this work is the first to apply machine learning for robust estimation of interaction effects in the presence of multiple treatments. We further establish the asymptotic distribution of our estimators and derive variance estimators for statistical inference. Extensive simulations demonstrate the performance of our methods. Finally, we apply the methods to study the effect of three treatments on HIV-associated kidney disease in an adult HIV cohort of 2455 participants in Nigeria.

Linear Collider Physics

Paul F. Derwent, Bogdan A. Dobrescu, Andreas S. Kronfeld, Heather E. Logan, Konstantin T. Matchev, Adam Para, David L. Rainwater, Slawomir Tkaczyk, William C. Wester

We report on a study of the physics potential of linear $e^+e^-$ colliders. Although a linear collider (LC) would support a broad physics program, we focus on the contributions that could help elucidate the origin of electroweak symmetry breaking. Many extensions of the standard model have a decoupling limit, with a Higgs boson similar to the standard one and other, higher-mass states. Mindful of such possibilities, we survey the physics of a (nearly) standard Higgs boson, as a function of its mass. We also review how measurements from an LC could help verify several well-motivated extensions of the standard model. For supersymmetry, we compare the strengths of an LC with the LHC. Also, assuming the lightest superpartner explains the missing dark matter in the universe, we examine other places to search for a signal of supersymmetry. We compare the signatures of several scenarios with extra spatial dimensions. We also explore the possibility that the Higgs is a composite, concentrating on models that (unlike technicolor) have a Higgs boson with mass of a few hundred GeV or less. Where appropriate, we mention the importance of high luminosity, for example to measure branching ratios of the Higgs, and the importance of multi-TeV energies, for example to explore the full spectrum of superpartners.

Project X: Physics Opportunities

Andreas S. Kronfeld, Robert S. Tschirhart, Usama Al-Binni, Wolfgang Altmannshofer, Charles Ankenbrandt, Kaladi Babu, Sunanda Banerjee, Matthew Bass, Brian Batell, David V. Baxter, Zurab Berezhiani, Marc Bergevin, Robert Bernstein, Sudeb Bhattacharya, Mary Bishai, Thomas Blum, S. Alex Bogacz, Stephen J. Brice, Joachim Brod, Alan Bross, Michael Buchoff, Thomas W. Burgess, Marcela Carena, Luis A. Castellanos, Subhasis Chattopadhyay, Mu-Chun Chen, Daniel Cherdack, Norman H. Christ, Tim Chupp, Vincenzo Cirigliano, Pilar Coloma, Christopher E. Coppola, Ramanath Cowsik, J. Allen Crabtree, André de Gouvêa, Jean-Pierre Delahaye, Dmitri Denisov, Patrick deNiverville, Ranjan Dharmapalan, Markus Diefenthaler, Alexander Dolgov, Georgi Dvali, Estia Eichten, Jürgen Engelfried, Phillip D. Ferguson, Tony Gabriel, Avraham Gal, Franz Gallmeier, Kenneth S. Ganezer, Susan Gardner, Douglas Glenzinski, Stephen Godfrey, Elena S. Golubeva, Stefania Gori, Van B. Graves, Geoffrey Greene, Cory L. Griffard, Ulrich Haisch, Thomas Handler, Brandon Hartfiel, Athanasios Hatzikoutelis, Ayman Hawari, Lawrence Heilbronn, James E. Hill, Patrick Huber, David E. Jaffe, Xiaodong Jiang, Christian Johnson, Yuri Kamyshkov, Daniel M. Kaplan, Boris Kerbikov, Brendan Kiburg, Harold G. Kirk, Andreas Klein, Kyle Knoepfel, Boris Kopeliovich, Vladimir Kopeliovich, Joachim Kopp, Wolfgang Korsch, Graham Kribs, Ronald Lipton, Chen-Yu Liu, Wolfgang Lorenzon, Zheng-Tian Lu, Naomi C. R. Makins, David McKeen, Geoffrey Mills, Michael Mocko, Rabindra Mohapatra, Nikolai V. Mokhov, Guenter Muhrer, Pieter Mumm, David Neuffer, Lev Okun, Mark A. Palmer, Robert Palmer, Robert W. Pattie, David G. Phillips, Kevin Pitts, Maxim Pospelov, Vitaly S. Pronskikh, Chris Quigg, Erik Ramberg, Amlan Ray, Paul E. Reimer, David G. Richards, Adam Ritz, Amit Roy, Arthur Ruggles, Robert Ryne, Utpal Sarkar, Andy Saunders, Yannis K. Semertzidis, Anatoly Serebrov, Hirohiko Shimizu, Robert Shrock, Arindam K. Sikdar, Pavel V. Snopok, William M. Snow, Aria Soha, Stefan Spanier, Sergei Striganov, Zhaowen Tang, Lawrence Townsend, Jon Urheim, Arkady Vainshtein, Richard Van de Water, Ruth S. Van de Water, Richard J. Van Kooten, Bernard Wehring, William C. Wester, Lisa Whitehead, Robert J. Wilson, Elizabeth Worcester, Albert R. Young, Geralyn Zeller