Author: "Depoy, D." - Searchworks@Jio Institute Digital Library Search Results

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1. The Dark Energy Survey: Cosmology Results With ~1500 New High-redshift Type Ia Supernovae Using The Full 5-year Dataset

Author: DES Collaboration, Abbott, T. M. C., Acevedo, M., Aguena, M., Alarcon, A., Allam, S., Alves, O., Amon, A., Andrade-Oliveira, F., Annis, J., Armstrong, P., Asorey, J., Avila, S., Bacon, D., Bassett, B. A., Bechtol, K., Bernardinelli, P. H., Bernstein, G. M., Bertin, E., Blazek, J., Bocquet, S., Brooks, D., Brout, D., Buckley-Geer, E., Burke, D. L., Camacho, H., Camilleri, R., Campos, A., Rosell, A. Carnero, Carollo, D., Carr, A., Carretero, J., Castander, F. J., Cawthon, R., Chang, C., Chen, R., Choi, A., Conselice, C., Costanzi, M., da Costa, L. N., Crocce, M., Davis, T. M., DePoy, D. L., Desai, S., Diehl, H. T., Dixon, M., Dodelson, S., Doel, P., Doux, C., Drlica-Wagner, A., Elvin-Poole, J., Everett, S., Ferrero, I., Ferté, A., Flaugher, B., Foley, R. J., Fosalba, P., Friedel, D., Frieman, J., Frohmaier, C., Galbany, L., García-Bellido, J., Gatti, M., Gaztanaga, E., Giannini, G., Glazebrook, K., Graur, O., Gruen, D., Gruendl, R. A., Gutierrez, G., Hartley, W. G., Herner, K., Hinton, S. R., Hollowood, D. L., Honscheid, K., Huterer, D., Jain, B., James, D. J., Jeffrey, N., Kasai, E., Kelsey, L., Kent, S., Kessler, R., Kim, A. G., Kirshner, R. P., Kovacs, E., Kuehn, K., Lahav, O., Lee, J., Lee, S., Lewis, G. F., Li, T. S., Lidman, C., Lin, H., Malik, U., Marshall, J. L., Martini, P., Mena-Fernández, J., Menanteau, F., Miquel, R., Mohr, J. J., Mould, J., Muir, J., Möller, A., Neilsen, E., Nichol, R. C., Nugent, P., Ogando, R. L. C., Palmese, A., Pan, Y. -C., Paterno, M., Percival, W. J., Pereira, M. E. S., Pieres, A., Malagón, A. A. Plazas, Popovic, B., Porredon, A., Prat, J., Qu, H., Raveri, M., Rodríguez-Monroy, M., Romer, A. K., Roodman, A., Rose, B., Sako, M., Sanchez, E., Cid, D. Sanchez, Schubnell, M., Scolnic, D., Sevilla-Noarbe, I., Shah, P., Smith, J. Allyn., Smith, M., Soares-Santos, M., Suchyta, E., Sullivan, M., Suntzeff, N., Swanson, M. E. C., Sánchez, B. O., Tarle, G., Taylor, G., Thomas, D., To, C., Toy, M., Troxel, M. A., Tucker, B. E., Tucker, D. L., Uddin, S. A., Vincenzi, M., Walker, A. R., Weaverdyck, N., Wechsler, R. H., Weller, J., Wester, W., Wiseman, P., Yamamoto, M., Yuan, F., Zhang, B., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present cosmological constraints from the sample of Type Ia supernovae (SN Ia) discovered during the full five years of the Dark Energy Survey (DES) Supernova Program. In contrast to most previous cosmological samples, in which SN are classified based on their spectra, we classify the DES SNe using a machine learning algorithm applied to their light curves in four photometric bands. Spectroscopic redshifts are acquired from a dedicated follow-up survey of the host galaxies. After accounting for the likelihood of each SN being a SN Ia, we find 1635 DES SNe in the redshift range $0.100.5$ SNe compared to the previous leading compilation of Pantheon+, and results in the tightest cosmological constraints achieved by any SN data set to date. To derive cosmological constraints we combine the DES supernova data with a high-quality external low-redshift sample consisting of 194 SNe Ia spanning $0.025
Published: 2024

2. The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections

Author: Gebhardt, Karl, Cooper, Erin Mentuch, Ciardullo, Robin, Acquaviva, Viviana, Bender, Ralf, Bowman, William P., Castanheira, Barbara G., Dalton, Gavin, Davis, Dustin, de Jong, Roelof S., DePoy, D. L., Devarakonda, Yaswant, Dongsheng, Sun, Drory, Niv, Fabricius, Maximilian, Farrow, Daniel J., Feldmeier, John, Finkelstein, Steven L., Froning, Cynthia S., Gawiser, Eric, Gronwall, Caryl, Herold, Laura, Hill, Gary J., Hopp, Ulrich, House, Lindsay R., Janowiecki, Steven, Jarvis, Matthew, Jeong, Donghui, Jogee, Shardha, Kakuma, Ryota, Kelz, Andreas, Kollatschny, W., Komatsu, Eiichiro, Krumpe, Mirko, Landriau, Martin, Liu, Chenxu, Niemeyer, Maja Lujan, MacQueen, Phillip, Marshall, Jennifer, Mawatari, Ken, McLinden, Emily M., Mukae, Shiro, Nagaraj, Gautam, Ono, Yoshiaki, Ouchi, Masami, Papovich, Casey, Sakai, Nao, Saito, Shun, Schneider, Donald P., Schulze, Andreas, Shanmugasundararaj, Khavvia, Shetrone, Matthew, Sneden, Chris, Snigula, Jan, Steinmetz, Matthias, Thomas, Benjamin P., Thomas, Brianna, Tuttle, Sarah, Urrutia, Tanya, Wisotzki, Lutz, Wold, Isak, Zeimann, Gregory, and Zhang, Yechi
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We describe the survey design, calibration, commissioning, and emission-line detection algorithms for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the redshifts of over a million Ly$\alpha$ emitting galaxies between 1.88
Published: 2021
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3. The HETDEX Instrumentation: Hobby-Eberly Telescope Wide Field Upgrade and VIRUS

Author: Hill, Gary J., Lee, Hanshin, MacQueen, Phillip J., Kelz, Andreas, Drory, Niv, Vattiat, Brian L., Good, John M., Ramsey, Jason, Kriel, Herman, Peterson, Trent, DePoy, D. L., Gebhardt, Karl, Marshall, J. L., Tuttle, Sarah E., Bauer, Svend M., Chonis, Taylor S., Fabricius, Maximilian H., Froning, Cynthia, Haeuser, Marco, Indahl, Briana L., Jahn, Thomas, Landriau, Martin, Leck, Ron, Montesano, Francesco, Prochaska, Travis, Snigula, Jan M., Zeimann, Gregory R., Bryant, Randy, Damm, George, Fowler, J. R., Janowiecki, Steven, Martin, Jerry, Mrozinski, Emily, Odewahn, Stephen, Rostopchin, Sergey, Shetrone, Matthew, Spencer, Renny, Cooper, Erin Mentuch, Armandroff, Taft, Bender, Ralf, Dalton, Gavin, Hopp, Ulrich, Komatsu, Eiichiro, Nicklas, Harald, Ramsey, Lawrence W., Roth, Martin M., Schneider, Donald P., Sneden, Chris, and Steinmetz, Matthias
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The Hobby-Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is undertaking a blind wide-field low-resolution spectroscopic survey of 540 square degrees of sky to identify and derive redshifts for a million Lyman-alpha emitting galaxies (LAEs) in the redshift range 1.9 < z < 3.5. The ultimate goal is to measure the expansion rate of the Universe at this epoch, to sharply constrain cosmological parameters and thus the nature of dark energy. A major multi-year wide field upgrade (WFU) of the HET was completed in 2016 that substantially increased the field of view to 22 arcminutes diameter and the pupil to 10 meters, by replacing the optical corrector, tracker, and prime focus instrument package and by developing a new telescope control system. The new, wide-field HET now feeds the Visible Integral-field Replicable Unit Spectrograph (VIRUS), a new low-resolution integral field spectrograph (LRS2), and the Habitable Zone Planet Finder (HPF), a precision near-infrared radial velocity spectrograph. VIRUS consists of 156 identical spectrographs fed by almost 35,000 fibers in 78 integral field units arrayed at the focus of the upgraded HET. VIRUS operates in a bandpass of 3500-5500 Angstroms with resolving power R~800. VIRUS is the first example of large scale replication applied to instrumentation in optical astronomy to achieve spectroscopic surveys of very large areas of sky. This paper presents technical details of the HET WFU and VIRUS, as flowed-down from the HETDEX science requirements, along with experience from commissioning this major telescope upgrade and the innovative instrumentation suite for HETDEX., Comment: 65 pages, 25 figures, published in the Astronomical Journal; replaced with final published version
Published: 2021
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4. The Exoplanet Transmission Spectroscopy Imager (ETSI)

Author: Limbach, Mary Anne, Schmidt, Luke M., DePoy, D. L., Mason, Jeffrey C., Scobey, Mike, Brown, Pat, Taylor, Chelsea, and Marshall, Jennifer L.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the design of a novel instrument tuned to detect transiting exoplanet atmospheres. The instrument, which we call the exoplanet transmission spectroscopy imager (ETSI), makes use of a new technique called common-path multi-band imaging (CMI). ETSI uses a prism and multi-band filter to simultaneously image 15 spectral bandpasses on two detectors from $430-975nm$ (with a average spectral resolution of $R = \lambda/\Delta\lambda = 23$) during exoplanet transits of a bright star. A prototype of the instrument achieved photon-noise limited results which were below the atmospheric amplitude scintillation noise limit. ETSI can detect the presence and composition of an exoplanet atmosphere in a relatively short time on a modest-size telescope. We show the optical design of the instrument. Further, we discuss design trades of the prism and multi-band filter which are driven by the science of the ETSI instrument. We describe the upcoming survey with ETSI that will measure dozens of exoplanet atmosphere spectra in $\sim2$ years on a two meter telescope. Finally, we will discuss how ETSI will be a powerful means for follow up on all gas giant exoplanets that transit bright stars, including a multitude of recently identified TESS (NASA's Transiting Exoplanet Survey Satellite) exoplanets., Comment: 14 pages, 9 figures, Proc. of SPIE 11447-100
Published: 2020

5. OGLE-2013-BLG-0911Lb: A Secondary on the Brown-Dwarf Planet Boundary around an M-dwarf

Author: Miyazaki, Shota, Sumi, Takahiro, Bennett, David P., Udalski, Andrzej, Shvartzvald, Yossi, Street, Rachel, Bozza, Valerio, Yee, Jennifer C., Bond, Ian A., Rattenbury, Nicholas, Koshimoto, Naoki, Suzuki, Daisuke, Fukui, Akihiko, Abe, F., Bhattacharya, A., Barry, R., Donachie, M., Fujii, H., Hirao, Y., Itow, Y., Kamei, Y., Kondo, I., Li, M. C. A., Ling, C. H., Matsubara, Y., Matsuo, T., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Saito, T., Sharan, A., Shibai, H., Suematsu, H., Sullivan, D. J., Tristram, P. J., Yamakawa, T., Yonehara, A., Skowron, J., Poleski, R., Mr'oz, P., Szyma'nski, M. K., Soszy'nski, I., Pietrukowicz, P., KozLowski, S., Ulaczyk, K., Wyrzykowski, L., Friedmann, Matan, Kaspi, Shai, Maoz, Dan, Albrow, M., Christie, G., DePoy, D. L., Gal-Yam, A., Gould, A., Lee, C. -U., Manulis, I., McCormick, J., Natusch, T., Ngan, H., Pogge, R. W., Porritt, I., Tsapras, Y., Bachelet, E., Hundertmark, M. P. G., Dominik, M., Bramich, D. M., Cassan, A., Jaimes, R. Figuera, Horne, K., Schmidt, R., Snodgrass, C., Wambsganss, J., Steele, I. A., Menzies, J., Mao, S., Jorgensen, U. G., Burgdorf, M. J., Ciceri, S., Novati, S. Calchi, D'Ago, G., Evans, D. F., Hinse, T. C., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Peixinho, N., and Verma, P.
Subjects: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the analysis of the binary-lens microlensing event OGLE-2013-BLG-0911. The best-fit solutions indicate the binary mass ratio of q~0.03 which differs from that reported in Shvartzvald+2016. The event suffers from the well-known close/wide degeneracy, resulting in two groups of solutions for the projected separation normalized by the Einstein radius of s~0.15 or s~7. The finite source and the parallax observations allow us to measure the lens physical parameters. The lens system is an M-dwarf orbited by a massive Jupiter companion at very close (M_{host}=0.30^{+0.08}_{-0.06} M_{Sun}, M_{comp}=10.1^{+2.9}_{-2.2} M_{Jup}, a_{exp}=0.40^{+0.05}_{-0.04} au) or wide (M_{host}=0.28^{+0.10}_{-0.08} M_{Sun}, M_{comp}=9.9^{+3.8}_{-3.5}M_{Jup}, a_{exp}=18.0^{+3.2}_{-3.2} au) separation. Although the mass ratio is slightly above the planet-brown dwarf (BD) mass-ratio boundary of q=0.03 which is generally used, the median physical mass of the companion is slightly below the planet-BD mass boundary of 13M_{Jup}. It is likely that the formation mechanisms for BDs and planets are different and the objects near the boundaries could have been formed by either mechanism. It is important to probe the distribution of such companions with masses of ~13M_{Jup} in order to statistically constrain the formation theories for both BDs and massive planets. In particular, the microlensing method is able to probe the distribution around low-mass M-dwarfs and even BDs which is challenging for other exoplanet detection methods., Comment: 22 pages, 10 figures, Accepted for publication in The Astronomical Journal
Published: 2019
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6. KELT-24b: A 5M$_{\rm J}$ Planet on a 5.6 day Well-Aligned Orbit around the Young V=8.3 F-star HD 93148

Author: Rodriguez, Joseph E., Eastman, Jason D., Zhou, George, Quinn, Samuel N., Beatty, Thomas G., Penev, Kaloyan, Johnson, Marshall C., Cargile, Phillip A., Latham, David W., Bieryla, Allyson, Collins, Karen A., Dressing, Courtney D., Ciardi, David R., Relles, Howard M., Murawski, Gabriel, Nishiumi, Taku, Yonehara, Atsunori, Ishimaru, Ryo, Yoshida, Fumi, Gregorio, Joao, Lund, Michael B., Stevens, Daniel J., Stassun, Keivan G., Gaudi, B. Scott, Colón, Knicole D., Pepper, Joshua, Narita, Norio, Awiphan, Supachai, Chuanraksasat, Pongpichit, Benni, Paul, Zambelli, Roberto, Garrison, Lehman H., Wilson, Maurice L., Cornachione, Matthew A., Wang, Sharon X., Labadie-Bartz, Jonathan, Rodríguez, Romy, Siverd, Robert J., Yao, Xinyu, Bayliss, Daniel, Berlind, Perry, Calkins, Michael L., Christiansen, Jessie L., Cohen, David H., Conti, Dennis M., Curtis, Ivan A., Depoy, D. L., Esquerdo, Gilbert A., Evans, Phil, Feliz, Dax, Fulton, Benjamin J., Holoien, Thomas W. S., James, David J., Jayasinghe, Tharindu, Jang-Condell, Hannah, Jensen, Eric L. N., Johnson, John A., Joner, Michael D., Khakpash, Somayeh, Kielkopf, John F., Kuhn, Rudolf B., Manner, Mark, Marshall, Jennifer L., McLeod, Kim K., McCrady, Nate, Oberst, Thomas E., Oelkers, Ryan J., Penny, Matthew T., Reed, Phillip A., Sliski, David H., Shappee, B. J., Stephens, Denise C., Stockdale, Chris, Tan, Thiam-Guan, Trueblood, Mark, Trueblood, Pat, Villanueva Jr., Steven, Wittenmyer, Robert A., and Wright, Jason T.
Subjects: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V=8.3 mag, K=7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a $T_{\rm eff}$ =$6509^{+50}_{-49}$ K, a mass of $M_{*}$ = $1.460^{+0.055}_{-0.059}$ $M_{\odot}$, radius of $R_{*}$ = $1.506\pm0.022$ $R_{\odot}$, and an age of $0.78^{+0.61}_{-0.42}$ Gyr. Its planetary companion (KELT-24 b) has a radius of $R_{\rm P}$ = $1.272\pm0.021$ $R_{\rm J}$, a mass of $M_{\rm P}$ = $5.18^{+0.21}_{-0.22}$ $M_{\rm J}$, and from Doppler tomographic observations, we find that the planet's orbit is well-aligned to its host star's projected spin axis ($\lambda$ = $2.6^{+5.1}_{-3.6}$). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs., Comment: 18 pages, 10 Figures, 6 Tables, Accepted to the Astronomical Journal
Published: 2019
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7. Achieving Transformative Understanding of Extreme Stellar Explosions with ELT-enabled Late-time Spectroscopy

Author: Milisavljevic, D., Margutti, R., Chornock, R., Rest, A., Graham, M., DePoy, D., Marshall, J., Golkhou, V. Z., Williams, G., Rho, J., Street, R., Skidmore, W., Haojing, Y., Bloom, J., Starrfield, S., Lee, C. -H., Cowperthwaite, P. S., Stringfellow, G., Coppejans, D., Terreran, G., Sravan, N., Fox, O., Mauerhan, J., Long, K. S., Blair, W. P., Winkler, P. F., Drout, M. R., Andrews, J., Kerzendorf, W., Wheeler, J. C., Filippenko, A. V., Smith, N., Metzger, B. D., Modjaz, M., Fesen, R. A., Berger, E., Garnavich, P., and Chevalier, R. A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Supernovae are among the most powerful and influential explosions in the universe. They are also ideal multi-messenger laboratories to study extreme astrophysics. However, many fundamental properties of supernovae related to their diverse progenitor systems and explosion mechanisms remain poorly constrained. Here we outline how late-time spectroscopic observations obtained during the nebular phase (several months to years after explosion), made possible with the next generation of Extremely Large Telescopes, will facilitate transformational science opportunities and rapidly accelerate the community towards our goal of achieving a complete understanding of supernova explosions. We highlight specific examples of how complementary GMT and TMT instrumentation will enable high fidelity spectroscopy from which the line profiles and luminosities of elements tracing mass loss and ejecta can be used to extract kinematic and chemical information with unprecedented detail, for hundreds of objects. This will provide uniquely powerful constraints on the evolutionary phases stars may experience approaching a supernova explosion; the subsequent explosion dynamics; their nucleosynthesis yields; and the formation of compact objects that may act as central engines., Comment: 9 pages, 3 figures, Astro2020 Science White Paper
Published: 2019

8. Chemical Abundance Analysis of Tucana III, the Second $r$-process Enhanced Ultra-Faint Dwarf Galaxy

Author: Marshall, J. L., Hansen, T., Simon, J. D., Li, T. S., Bernstein, R. A., Kuehn, K., Pace, A. B., DePoy, D. L., Palmese, A., Pieres, A., Strigari, L., Drlica-Wagner, A., Lidman, C., Nagasawa, D. Q., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., De Vicente, J., Desai, S., Doel, P., Eifler, T. F., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Hollowood, D. L., Honscheid, K., Hoyle, B., James, D. J., Kuropatkin, N., Maia, M. A. G., Menanteau, F., Miller, C. J., Miquel, R., Plazas, A. A., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M. E. C., Tarle, G., and Wester, W.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present a chemical abundance analysis of four additional confirmed member stars of Tucana III, a Milky Way satellite galaxy candidate in the process of being tidally disrupted as it is accreted by the Galaxy. Two of these stars are centrally located in the core of the galaxy while the other two stars are located in the eastern and western tidal tails. The four stars have chemical abundance patterns consistent with the one previously studied star in Tucana III: they are moderately enhanced in $r$-process elements, i.e. they have $<$[Eu/Fe]$> \approx +$0.4 dex. The non-neutron-capture elements generally follow trends seen in other dwarf galaxies, including a metallicity range of 0.44 dex and the expected trend in $\alpha$-elements, i.e., the lower metallicity stars have higher Ca and Ti abundance. Overall, the chemical abundance patterns of these stars suggest that Tucana III was an ultra-faint dwarf galaxy, and not a globular cluster, before being tidally disturbed. As is the case for the one other galaxy dominated by $r$-process enhanced stars, Reticulum II, Tucana III's stellar chemical abundances are consistent with pollution from ejecta produced by a binary neutron star merger, although a different $r$-process element or dilution gas mass is required to explain the abundances in these two galaxies if a neutron star merger is the sole source of $r$-process enhancement., Comment: 18 pages, 10 figures; accepted by ApJ
Published: 2018
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9. More out of less: an excess integrated Sachs-Wolfe signal from supervoids mapped out by the Dark Energy Survey

Author: Kovács, A., Sánchez, C., García-Bellido, J., Elvin-Poole, J., Hamaus, N., Miranda, V., Nadathur, S., Abbott, T., Abdalla, F. B., Annis, J., Avila, S., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cawthon, R., Crocce, M., Cunha, C., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D., Desai, S., Diehl, H. T., Doel, P., Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., Gaztañaga, E., Gerdes, D., Gruendl, R., Gutierrez, G., Hartley, W., Hollowood, D. L., Honscheid, K., Hoyle, B., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M., March, M., Marshall, J., Melchior, P., Menanteau, F., Miller, C. J., Miquel, R., Mohr, J., Plazas, A. A., Romer, K., Rykoff, E., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M., Tarle, G., Thomas, D., Vikram, V., and Weller, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The largest structures in the cosmic web probe the dynamical nature of dark energy through their integrated Sachs-Wolfe imprints. In the strength of the signal, typical cosmic voids have shown good consistency with expectation $A_{\rm ISW}=\Delta T^{\rm data} / \Delta T^{\rm theory}=1$, given the substantial cosmic variance. Discordantly, large-scale hills in the gravitational potential, or supervoids, have shown excess signals. In this study, we mapped out 87 new supervoids in the total 5000 deg$^2$ footprint of the Dark Energy Survey at $0.2
Published: 2018
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10. Dark Energy Survey Year 1 Results: Constraints on Intrinsic Alignments and their Colour Dependence from Galaxy Clustering and Weak Lensing

Author: Samuroff, S., Blazek, J., Troxel, M. A., MacCrann, N., Krause, E., Leonard, C. D., Prat, J., Gruen, D., Dodelson, S., Eifler, T. F., Gatti, M., Hartley, W. G., Hoyle, B., Larsen, P., Zuntz, J., Abbott, T. M. C., Allam, S., Annis, J., Bernstein, G. M., Bertin, E., Bridle, S. L., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cunha, C. E., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Dietrich, J. P., Doel, P., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., Martini, P., Melchior, P., Menanteau, F., Miller, C. J., Miquel, R., Ogando, R. L. C., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Sheldon, E., Smith, M., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., and Vikram, V.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We perform a joint analysis of intrinsic alignments and cosmology using tomographic weak lensing, galaxy clustering and galaxy-galaxy lensing measurements from Year 1 (Y1) of the Dark Energy Survey. We define early- and late-type subsamples, which are found to pass a series of systematics tests, including for spurious photometric redshift error and point spread function correlations. We analyse these split data alongside the fiducial mixed Y1 sample using a range of intrinsic alignment models. In a fiducial Nonlinear Alignment Model (NLA) analysis, assuming a flat \lcdm~cosmology, we find a significant difference in intrinsic alignment amplitude, with early-type galaxies favouring $A_\mathrm{IA} = 2.38^{+0.32}_{-0.31}$ and late-type galaxies consistent with no intrinsic alignments at $0.05^{+0.10}_{-0.09}$. We find weak evidence of a diminishing alignment amplitude at higher redshifts in the early-type sample. The analysis is repeated using a number of extended model spaces, including a physically motivated model that includes both tidal torquing and tidal alignment mechanisms. In multiprobe likelihood chains in which cosmology, intrinsic alignments in both galaxy samples and all other relevant systematics are varied simultaneously, we find the tidal alignment and tidal torquing parts of the intrinsic alignment signal have amplitudes $A_1 = 2.66 ^{+0.67}_{-0.66}$, $A_2=-2.94^{+1.94}_{-1.83}$, respectively, for early-type galaxies and $A_1 = 0.62 ^{+0.41}_{-0.41}$, $A_2 = -2.26^{+1.30}_{-1.16}$ for late-type galaxies. In the full (mixed) Y1 sample the best constraints are $A_1 = 0.70 ^{+0.41}_{-0.38}$, $A_2 = -1.36 ^{+1.08}_{-1.41}$. For all galaxy splits and IA models considered, we report cosmological parameter constraints that are consistent with the results of Troxel et al. (2017) and Dark Energy Survey Collaboration (2017)., Comment: 31 pages, 23 figures; accepted by MNRAS
Published: 2018
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11. Steve: A hierarchical Bayesian model for Supernova Cosmology

Author: Hinton, S. R., Davis, T. M., Kim, A. G., Brout, D., D'Andrea, C. B., Kessler, R., Lasker, J., Lidman, C., Macaulay, E., Möller, A., Sako, M., Scolnic, D., Smith, M., Wolf, R. C., Childress, M., Morganson, E., Allam, S., Annis, J., Avila, S., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D. L., Doel, P., Eifler, T. F., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Hollowood, D. L., Honscheid, K., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., Menanteau, F., Miquel, R., Ogando, R. L. C., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., Vikram, V., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present a new Bayesian hierarchical model (BHM) named Steve for performing type Ia supernova (SNIa) cosmology fits. This advances previous works by including an improved treatment of Malmquist bias, accounting for additional sources of systematic uncertainty, and increasing numerical efficiency. Given light curve fit parameters, redshifts, and host-galaxy masses, we fit Steve simultaneously for parameters describing cosmology, SNIa populations, and systematic uncertainties. Selection effects are characterised using Monte-Carlo simulations. We demonstrate its implementation by fitting realisations of SNIa datasets where the SNIa model closely follows that used in Steve. Next, we validate on more realistic SNANA simulations of SNIa samples from the Dark Energy Survey and low-redshift surveys. These simulated datasets contain more than $60\,000$ SNeIa, which we use to evaluate biases in the recovery of cosmological parameters, specifically the equation-of-state of dark energy, $w$. This is the most rigorous test of a BHM method applied to SNIa cosmology fitting, and reveals small $w$-biases that depend on the simulated SNIa properties, in particular the intrinsic SNIa scatter model. This $w$-bias is less than $0.03$ on average, less than half the statistical uncertainty on $w$.These simulation test results are a concern for BHM cosmology fitting applications on large upcoming surveys, and therefore future development will focus on minimising the sensitivity of Steve to the SNIa intrinsic scatter model., Comment: 27 pages, 12 figures
Published: 2018
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12. First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey: Analysis, Systematic Uncertainties, and Validation

Author: Brout, D., Scolnic, D., Kessler, R., D'Andrea, C. B., Davis, T. M., Gupta, R. R., Hinton, S. R., Kim, A. G., Lasker, J., Lidman, C., Macaulay, E., Möller, A., Nichol, R. C., Sako, M., Smith, M., Sullivan, M., Zhang, B., Andersen, P., Asorey, J., Avelino, A., Bassett, B. A., Brown, P., Calcino, J., Carollo, D., Challis, P., Childress, M., Clocchiatti, A., Filippenko, A. V., Foley, R. J., Galbany, L., Glazebrook, K., Hoormann, J. K., Kasai, E., Kirshner, R. P., Kuehn, K., Kuhlmann, S., Lewis, G. F., Mandel, K. S., March, M., Miranda, V., Morganson, E., Muthukrishna, D., Nugent, P., Palmese, A., Pan, Y. -C., Sharp, R., Sommer, N. E., Swann, E., Thomas, R. C., Tucker, B. E., Uddin, S. A., Wester, W., Abbott, T. M. C., Allam, S., Annis, J., Avila, S., Bechtol, K., Bernstein, G. M., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cunha, C. E., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Drlica-Wagner, A., Eifler, T. F., Estrada, J., Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gruen, D., Gruendl, R. A., Gutierrez, G., Hartley, W. G., Hollowood, D. L., Honscheid, K., Hoyle, B., James, D. J., Jarvis, M., Jeltema, T., Krause, E., Lahav, O., Li, T. S., Lima, M., Maia, M. A. G., Marriner, J., Marshall, J. L., Martini, P., Menanteau, F., Miller, C. J., Miquel, R., Ogando, R. L. C., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Troxel, M. A., Tucker, D. L., Vikram, V., Walker, A. R., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present the analysis underpinning the measurement of cosmological parameters from 207 spectroscopically classified type Ia supernovae (SNe Ia) from the first three years of the Dark Energy Survey Supernova Program (DES-SN), spanning a redshift range of 0.017<$z$<0.849. We combine the DES-SN sample with an external sample of 122 low-redshift ($z$<0.1) SNe Ia, resulting in a "DES-SN3YR" sample of 329 SNe Ia. Our cosmological analyses are blinded: after combining our DES-SN3YR distances with constraints from the Cosmic Microwave Background (CMB; Planck Collaboration 2016), our uncertainties in the measurement of the dark energy equation-of-state parameter, $w$, are .042 (stat) and .059 (stat+syst) at 68% confidence. We provide a detailed systematic uncertainty budget, which has nearly equal contributions from photometric calibration, astrophysical bias corrections, and instrumental bias corrections. We also include several new sources of systematic uncertainty. While our sample is <1/3 the size of the Pantheon sample, our constraints on $w$ are only larger by 1.4$\times$, showing the impact of the DES SN Ia light curve quality. We find that the traditional stretch and color standardization parameters of the DES SNe Ia are in agreement with earlier SN Ia samples such as Pan-STARRS1 and the Supernova Legacy Survey. However, we find smaller intrinsic scatter about the Hubble diagram (0.077 mag). Interestingly, we find no evidence for a Hubble residual step ( 0.007 $\pm$ 0.018 mag) as a function of host galaxy mass for the DES subset, in 2.4$\sigma$ tension with previous measurements. We also present novel validation methods of our sample using simulated SNe Ia inserted in DECam images and using large catalog-level simulations to test for biases in our analysis pipelines., Comment: 30 Pages, 18 Figures, 12 Tables. Submitted to ApJ. Comments welcome
Published: 2018
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13. First Cosmology Results using Type Ia Supernovae from the Dark Energy Survey: Constraints on Cosmological Parameters

Author: Abbott, T. M. C., Allam, S., Andersen, P., Angus, C., Asorey, J., Avelino, A., Avila, S., Bassett, B. A., Bechtol, K., Bernstein, G. M., Bertin, E., Brooks, D., Brout, D., Brown, P., Burke, D. L., Calcino, J., Rosell, A. Carnero, Carollo, D., Kind, M. Carrasco, Carretero, J., Casas, R., Castander, F. J., Cawthon, R., Challis, P., Childress, M., Clocchiatti, A., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., Davis, T. M., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Drlica-Wagner, A., Eifler, T. F., Evrard, A. E., Fernandez, E., Filippenko, A. V., Finley, D. A., Flaugher, B., Foley, R. J., Fosalba, P., Frieman, J., Galbany, L., Garcia-Bellido, J., Gaztanaga, E., Giannantonio, T., Glazebrook, K., Goldstein, D. A., Gonzalez-Gaitan, S., Gruen, D., Gruendl, R. A., Gschwend, J., Gupta, R. R., Gutierrez, G., Hartley, W. G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Hoormann, J. K., Hoyle, B., James, D. J., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Kasai, E., Kent, S., Kessler, R., Kim, A. G., Kirshner, R. P., Kovacs, E., Krause, E., Kron, R., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lasker, J., Lewis, G. F., Li, T. S., Lidman, C., Lima, M., Lin, H., Macaulay, E., Maia, M. A. G., Mandel, K. S., March, M., Marriner, J., Marshall, J. L., Martini, P., Menanteau, F., Miller, C. J., Miquel, R., Miranda, V., Mohr, J. J., Morganson, E., Muthukrishna, D., Möller, A., Neilsen, E., Nichol, R. C., Nord, B., Nugent, P., Ogando, R. L. C., Palmese, A., Pan, Y. -C., Plazas, A. A., Pursiainen, M., Romer, A. K., Roodman, A., Rozo, E., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Scolnic, D., Serrano, S., Sevilla-Noarbe, I., Sharp, R., Smith, M., Soares-Santos, M., Sobreira, F., Sommer, N. E., Spinka, H., Suchyta, E., Sullivan, M., Swann, E., Tarle, G., Thomas, D., Thomas, R. C., Troxel, M. A., Tucker, B. E., Uddin, S. A., Walker, A. R., Wester, W., Wiseman, P., Wolf, R. C., Yanny, B., Zhang, B., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from the Dark Energy Survey Supernova Program (DES-SN). The analysis uses a subsample of 207 spectroscopically confirmed SNe Ia from the first three years of DES-SN, combined with a low-redshift sample of 122 SNe from the literature. Our "DES-SN3YR" result from these 329 SNe Ia is based on a series of companion analyses and improvements covering SN Ia discovery, spectroscopic selection, photometry, calibration, distance bias corrections, and evaluation of systematic uncertainties. For a flat LCDM model we find a matter density Omega_m = 0.331 +_ 0.038. For a flat wCDM model, and combining our SN Ia constraints with those from the cosmic microwave background (CMB), we find a dark energy equation of state w = -0.978 +_ 0.059, and Omega_m = 0.321 +_ 0.018. For a flat w0waCDM model, and combining probes from SN Ia, CMB and baryon acoustic oscillations, we find w0 = -0.885 +_ 0.114 and wa = -0.387 +_ 0.430. These results are in agreement with a cosmological constant and with previous constraints using SNe Ia (Pantheon, JLA).
Published: 2018
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14. Cosmological Constraints from Multiple Probes in the Dark Energy Survey

Author: DES Collaboration, Abbott, T. M. C., Alarcon, A., Allam, S., Andersen, P., Andrade-Oliveira, F., Annis, J., Asorey, J., Avelino, A., Avila, S., Bacon, D., Banik, N., Bassett, B. A., Baxter, E., Bechtol, K., Becker, M. R., Bernstein, G. M., Bertin, E., Blazek, J., Bridle, S. L., Brooks, D., Brout, D., Burke, D. L., Calcino, J., Camacho, H., Campos, A., Rosell, A. Carnero, Carollo, D., Kind, M. Carrasco, Carretero, J., Castander, F. J., Cawthon, R., Challis, P., Chan, K. C., Chang, C., Childress, M., Clocchiatti, A., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., Davis, T. M., De Vicente, J., DePoy, D. L., DeRose, J., Desai, S., Diehl, H. T., Dietrich, J. P., Dodelson, S., Doel, P., Drlica-Wagner, A., Eifler, T. F., Elvin-Poole, J., Estrada, J., Evrard, A. E., Fernandez, E., Filippenko, A. V., Flaugher, B., Foley, R. J., Fosalba, P., Frieman, J., Galbany, L., García-Bellido, J., Gatti, M., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Glazebrook, K., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Hoormann, J. K., Hoyle, B., Huterer, D., Jain, B., James, D. J., Jarvis, M., Jeltema, T., Kasai, E., Kent, S., Kessler, R., Kim, A. G., Kirshner, R. P., Kokron, N., Krause, E., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Lasker, J., Lemos, P., Lewis, G. F., Li, T. S., Lidman, C., Lima, M., Lin, H., Macaulay, E., MacCrann, N., Maia, M. A. G., Mandel, K. S., March, M., Marriner, J., Marshall, J. L., Martini, P., McMahon, R. G., Melchior, P., Menanteau, F., Miquel, R., Mohr, J. J., Morganson, E., Muir, J., Möller, A., Neilsen, E., Nichol, R. C., Nord, B., Ogando, R. L. C., Palmese, A., Pan, Y. -C., Peiris, H. V., Percival, W. J., Plazas, A. A., Porredon, A., Prat, J., Romer, A. K., Roodman, A., Rosenfeld, R., Ross, A. J., Rykoff, E. S., Samuroff, S., Sánchez, C., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Scolnic, D., Secco, L. F., Serrano, S., Sevilla-Noarbe, I., Sharp, R., Sheldon, E., Smith, M., Soares-Santos, M., Sobreira, F., Sommer, N. E., Swann, E., Swanson, M. E. C., Tarle, G., Thomas, D., Thomas, R. C., Troxel, M. A., Tucker, B. E., Uddin, S. A., Vielzeuf, P., Walker, A. R., Wang, M., Weaverdyck, N., Wechsler, R. H., Weller, J., Yanny, B., Zhang, B., Zhang, Y., and Zuntz, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically--confirmed Type Ia supernova lightcurves; the baryon acoustic oscillation feature; weak gravitational lensing; and galaxy clustering. Here we present combined results from these probes, deriving constraints on the equation of state, $w$, of dark energy and its energy density in the Universe. Independently of other experiments, such as those that measure the cosmic microwave background, the probes from this single photometric survey rule out a Universe with no dark energy, finding $w=-0.80^{+0.09}_{-0.11}$. The geometry is shown to be consistent with a spatially flat Universe, and we obtain a constraint on the baryon density of $\Omega_b=0.069^{+0.009}_{-0.012}$ that is independent of early Universe measurements. These results demonstrate the potential power of large multi-probe photometric surveys and pave the way for order of magnitude advances in our constraints on properties of dark energy and cosmology over the next decade., Comment: 8 pages, 2 figures; v3 matches version accepted by PRL
Published: 2018
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15. The morphology and structure of stellar populations in the Fornax dwarf spheroidal galaxy from Dark Energy Survey Data

Author: Wang, Mei-Yu, de Boer, T., Pieres, A., Li, T. S., Drlica-Wagner, A., Koposov, S. E., Vivas, A. K., Pace, A. B., Santiago, B., Walker, A. R., Tucker, D. L., Strigari, L., Marshall, J. L., Yanny, B., DePoy, D. L., Bechtol, K., Roodman, A., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Avila, S., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Cunha, C. E., D'Andrea, C. B., da Costa, L. N., De Vicente, J., Desai, S., Eifler, T. F., Estrada, J., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gutierrez, G., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lahav, O., Maia, M. A. G., Miquel, R., Sanchez, E., Scarpine, V., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., and Tarle, G.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Using deep wide-field photometry three-year data (Y3) from the Dark Energy Survey (DES), we present a panoramic study of the Fornax dwarf spheroidal galaxy. The data presented here -- a small subset of the full survey -- uniformly covers a region of 25 square degrees centered on the galaxy to a depth of g ~ 23.5. We use this data to study the structural properties of Fornax, overall stellar population, and its member stars in different evolutionary phases. We also search for possible signs of tidal disturbance. Fornax is found to be significantly more spatially extended than what early studies suggested. No statistically significant distortions or signs of tidal disturbances were found down to a surface brightness limit of ~32.1 mag/arcsec^2. However, there are hints of shell-like features located ~30' - 40' from the center of Fornax that may be stellar debris from past merger events. We also find that intermediate age and young main-sequence populations show different orientation at the galaxy center and have many substructures. The deep DES Y3 data allows us to characterize the age of those substructures with great accuracy, both those previously known and those newly discovered in this work, on the basis of their color-magnitude diagram morphology. We find that the youngest overdensities are all found on the Eastern side of Fornax, where the Fornax field population itself is slightly younger than in the West. The high quality DES Y3 data reveals that Fornax has many rich structures, and provides insights into its complex formation history., Comment: 15 pages, 10 figures, 3 tables, submitted to ApJ
Published: 2018
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16. On the relative bias of void tracers in the Dark Energy Survey

Author: Pollina, G., Hamaus, N., Paech, K., Dolag, K., Weller, J., Sánchez, C., Rykoff, E. S., Jain, B., Abbott, T. M. C., Allam, S., Avila, S., Bernstein, R. A., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Giannantonio, T., Gruen, D., Gschwend, J., Gutierrez, G., Hartley, W. G., Hollowood, D. L., Honscheid, K., Hoyle, B., James, D. J., Jeltema, T., Kuehn, K., Kuropatkin, N., Lima, M., March, M., Marshall, J. L., Melchior, P., Menanteau, F., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Walker, A. R., and Wester, W.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Luminous tracers of large-scale structure are not entirely representative of the distribution of mass in our Universe. As they arise from the highest peaks in the matter density field, the spatial distribution of luminous objects is biased towards those peaks. On large scales, where density fluctuations are mild, this bias simply amounts to a constant offset in the clustering amplitude of the tracer, known as linear bias. In this work we focus on the relative bias between galaxies and galaxy clusters that are located inside and in the vicinity of cosmic voids, extended regions of relatively low density in the large-scale structure of the Universe. With the help of hydro-dynamical simulations we verify that the relation between galaxy and cluster overdensity around voids remains linear. Hence, the void-centric density profiles of different tracers can be linked by a single multiplicative constant. This amounts to the same value as the relative linear bias between tracers for the largest voids in the sample. For voids of small sizes, which typically arise in higher density regions, this constant has a higher value, possibly showing an environmental dependence similar to that observed for the linear bias itself. We confirm our findings by analysing mocks and data obtained during the first year of observations by the Dark Energy Survey. As a side product, we present the first catalogue of three-dimensional voids extracted from a photometric survey with a controlled photo-z uncertainty. Our results will be relevant in forthcoming analyses that attempt to use voids as cosmological probes., Comment: 17 pages, 13 figures, MNRAS submitted
Published: 2018
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17. Systems engineering applied to ELT instrumentation: The GMACS case

Author: Faes, D. M., Souza, A., Froning, C., Schmidt, L., Bortoletto, D., Cook, E., DePoy, D. L., Ji, T. -G., Jones, D., Lee, H. -I., Marshall, J. L., Oliveira, C. M., Pak, S., Papovich, C., Prochaska, T., Ribeiro, R., and Taylor, K.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: An important tool for the development of the next generation of extremely large telescopes (ELTs) is a robust Systems Engineering (SE) methodology. GMACS is a first-generation multi-object spectrograph that will work at visible wavelengths on the Giant Magellan Telescope (GMT). In this paper, we discuss the application of SE to the design of next-generation instruments for ground-based astronomy and present the ongoing development of SE products for the GMACS spectrograph, currently in its Conceptual Design phase. SE provides the means to assist in the management of complex projects, and in the case of GMACS, to ensure its operational success, maximizing the scientific potential of GMT., Comment: To appear in Proc. SPIE 10705 (Ground-based and Airborne Instrumentation for Astronomy VII, SPIEastro18)
Published: 2018
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18. The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign. II. New quasar lenses from double component fitting

Author: Anguita, T., Schechter, P. L., Kuropatkin, N., Morgan, N. D., Ostrovski, F., Abramson, L. E., Agnello, A., Apostolovski, Y., Fassnacht, C. D., Hsueh, J. W., Motta, V., Rojas, K., Rusu, C. E., Treu, T., Williams, P., Auger, M., Buckley-Geer, E., Lin, H., McMahon, R., Abbott, T. M. C., Allam, S., Annis, J., Bernstein, R. A., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Flaugher, B., García-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Hartley, W. G., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Lima, M., Maia, M. A. G., Miquel, R., Plazas, A. A., Sanchez, E., Scarpine, V., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., and Walker, A. R.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We report upon the follow up of 34 candidate lensed quasars found in the Dark Energy Survey using NTT-EFOSC, Magellan-IMACS, KECK-ESI and SOAR-SAMI. These candidates were selected by a combination of double component fitting, morphological assessment and color analysis. Most systems followed up are indeed composed of at least one quasar image and 13 with two or more quasar images: two lenses, four projected binaries and seven Nearly Identical Quasar Pairs (NIQs). The two systems confirmed as genuine gravitationally lensed quasars are one quadruple at $z_s=1.713$ and one double at $z_s=1.515$. Lens modeling of these two systems reveals that both systems require very little contribution from the environment to reproduce the image configuration. Nevertheless, small flux anomalies can be observed in one of the images of the quad. Further observations of 9 inconclusive systems (including 7 NIQs) will allow to confirm (or not) their gravitational lens nature., Comment: 13 pages, 8 figures. MNRAS submitted (05/24). Approved by the DES Collaboration Wide Review
Published: 2018
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19. Dark Energy Survey Year 1 Results: Methodology and Projections for Joint Analysis of Galaxy Clustering, Galaxy Lensing, and CMB Lensing Two-point Functions

Author: Baxter, E. J., Omori, Y., Chang, C., Giannantonio, T., Kirk, D., Krause, E., Blazek, J., Bleem, L., Choi, A., Crawford, T. M., Dodelson, S., Eifler, T. F., Friedrich, O., Gruen, D., Holder, G. P., Jain, B., Jarvis, M., MacCrann, N., Nicola, A., Pandey, S., Prat, J., Reichardt, C. L., Samuroff, S., Sánchez, C., Secco, L. F., Sheldon, E., Troxel, M. A., Zuntz, J., Abbott, T. M. C., Abdalla, F. B., Annis, J., Avila, S., Bechtol, K., Benson, B. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cawthon, R., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D. L., Diehl, H. T., Doel, P., Estrada, J., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Hollowood, D., Hoyle, B., James, D. J., Kent, S., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., Melchior, P., Menanteau, F., Miquel, R., Plazas, A. A., Roodman, A., Rykoff, E. S., Sanchez, E., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Walker, A. R., Wu, W. L. K., and Weller, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Optical imaging surveys measure both the galaxy density and the gravitational lensing-induced shear fields across the sky. Recently, the Dark Energy Survey (DES) collaboration used a joint fit to two-point correlations between these observables to place tight constraints on cosmology (DES Collaboration et al. 2017). In this work, we develop the methodology to extend the DES year one joint probes analysis to include cross-correlations of the optical survey observables with gravitational lensing of the cosmic microwave background (CMB) as measured by the South Pole Telescope (SPT) and Planck. Using simulated analyses, we show how the resulting set of five two-point functions increases the robustness of the cosmological constraints to systematic errors in galaxy lensing shear calibration. Additionally, we show that contamination of the SPT+Planck CMB lensing map by the thermal Sunyaev-Zel'dovich effect is a potentially large source of systematic error for two-point function analyses, but show that it can be reduced to acceptable levels in our analysis by masking clusters of galaxies and imposing angular scale cuts on the two-point functions. The methodology developed here will be applied to the analysis of data from the DES, the SPT, and Planck in a companion work., Comment: 21 pages, 11 figures; matches version resubmitted to journal
Published: 2018
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20. The Dark Energy Survey Data Release 1

Author: Abbott, T. M. C., Abdalla, F. B., Allam, S., Amara, A., Annis, J., Asorey, J., Avila, S., Ballester, O., Banerji, M., Barkhouse, W., Baruah, L., Baumer, M., Bechtol, K., Becker, M . R., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Blazek, J., Bocquet, S., Brooks, D., Brout, D., Buckley-Geer, E., Burke, D. L., Busti, V., Campisano, R., Cardiel-Sas, L., Rosell, A. C arnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cawthon, R., Chang, C., Chen, X., Conselice, C., Costa, G., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Das, R., Daues, G., Davis, T. M., Davis, C., De Vicente, J., DePoy, D. L., DeRose, J., Desai, S., Diehl, H. T., Dietrich, J. P., Dodelson, S., Doel, P., Drlica-Wagner, A., Eifler, T. F., Elliott, A. E., Evrard, A. E., Farahi, A., Neto, A. Fausti, Fernandez, E., Finley, D. A., Fitzpatrick, M., Flaugher, B., Foley, R. J., Fosalba, P., Friedel, D. N., Frieman, J., García-Bellido, J., tanaga, E. Gaz, Gerdes, D. W., Giannantonio, T., Gill, M. S. S., Glazebrook, K., Goldstein, D. A., Gower, M., Gruen, D., Gruendl, R. A., Gschwend, J., Gupta, R. R., Gutierrez, G., Hamilton, S., Hartley, W. G., Hinton, S. R., Hislop, J. M., Hollowood, D., Honscheid, K., Hoyle, B., Huterer, D., Jain, B., James, D. J., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Juneau, S., Kacprzak, T., Kent, S., Khullar, G., Klein, M., Kovacs, A., Koziol, A. M. G., Krause, E., Kremin, A., Kron, R., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lasker, J., Li, T. S., Li, R. T., Liddle, A. R., Lima, M., Lin, H., López-Reyes, P., MacCrann, N., Maia, M. A. G., Maloney, J. D., Manera, M., March, M., Marriner, J., Marshall, J. L., Martini, P., McClintock, T., McKay, T., McMahon, R . G., Melchior, P., Menanteau, F., Miller, C. J., Miquel, R., Mohr, J. J., Morganson, E., Mould, J., Neilsen, E., Nichol, R. C., Nidever, D., Nikutta, R., Nogueira, F., Nord, B., Nugent, P., Nunes, L., Ogando, R. L. C., Old, L., Olsen, K., Pace, A. B., Palmese, A., Paz-Chinchón, F., Peiris, H. V., Percival, W. J., Petravick, D., Plazas, A. A., Poh, J., Pond, C., redon, A. Por, Pujol, A., Refregier, A., Reil, K., Ricker, P. M., Rollins, R. P., Romer, A. K., Roodman, A., Rooney, P., Ross, A. J., Rykoff, E. S., Sako, M., Sanchez, E., Sanchez, M. L., Santiago, B., Saro, A., Scarpine, V., Scolnic, D., Scott, A., Serrano, S., Sevilla-Noarbe, I., Sheldon, E., Shipp, N., Silveira, M. L., Smith, R. C., Smith, J. A., Smith, M., Soares-Santos, M., ira, F. Sobre, Song, J., Stebbins, A., Suchyta, E., Sullivan, M., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Thomas, R. C., Troxel, M. A., Tucker, D. L., Vikram, V., Vivas, A. K., ker, A. R. Wal, Wechsler, R. H., Weller, J., Wester, W., Wolf, R. C., Wu, H., Yanny, B., Zenteno, A., Zhang, Y., and Zuntz, J.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We describe the first public data release of the Dark Energy Survey, DES DR1, consisting of reduced single epoch images, coadded images, coadded source catalogs, and associated products and services assembled over the first three years of DES science operations. DES DR1 is based on optical/near-infrared imaging from 345 distinct nights (August 2013 to February 2016) by the Dark Energy Camera mounted on the 4-m Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. We release data from the DES wide-area survey covering ~5,000 sq. deg. of the southern Galactic cap in five broad photometric bands, grizY. DES DR1 has a median delivered point-spread function of g = 1.12, r = 0.96, i = 0.88, z = 0.84, and Y = 0.90 arcsec FWHM, a photometric precision of < 1% in all bands, and an astrometric precision of 151 mas. The median coadded catalog depth for a 1.95" diameter aperture at S/N = 10 is g = 24.33, r = 24.08, i = 23.44, z = 22.69, and Y = 21.44 mag. DES DR1 includes nearly 400M distinct astronomical objects detected in ~10,000 coadd tiles of size 0.534 sq. deg. produced from ~39,000 individual exposures. Benchmark galaxy and stellar samples contain ~310M and ~ 80M objects, respectively, following a basic object quality selection. These data are accessible through a range of interfaces, including query web clients, image cutout servers, jupyter notebooks, and an interactive coadd image visualization tool. DES DR1 constitutes the largest photometric data set to date at the achieved depth and photometric precision., Comment: 30 pages, 20 Figures. Release page found at this url https://des.ncsa.illinois.edu/releases/dr1
Published: 2018
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21. UV-Luminous, Star-Forming Hosts of z~2 Reddened Quasars in the Dark Energy Survey

Author: Wethers, C. F., Banerji, M., Hewett, P. C., Lemon, C. A., McMahon, R. G., Reed, S. L., Shen, Y., Abdalla, F. B., Benoit-Lévy, A., Brooks, D., Buckley-Geer, E., Capozzi, D., Rosell, A. Carnero, CarrascoKind, M., Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Jeltema, T., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Martini, P., Menanteau, F., Miquel, R., Nichol, R. C., Nord, B., Plazas, A. A., Romer, A. K., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., and Walker, A. R.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the first rest-frame UV population study of 17 heavily reddened, high-luminosity (E(B-V)$_{\rm{QSO}}\gtrsim$ 0.5; L$_{\rm{bol}}>$ 10$^{46}$ergs$^{-1}$) broad-line quasars at $1.5 < z < 2.7$. We combine the first year of deep, optical, ground-based observations from the Dark Energy Survey (DES) with the near infrared VISTA Hemisphere Survey (VHS) and UKIDSS Large Area Survey (ULAS) data, from which the reddened quasars were initially identified. We demonstrate that the significant dust reddening towards the quasar in our sample allows host galaxy emission to be detected at the rest-frame UV wavelengths probed by the DES photometry. By exploiting this reddening effect, we disentangle the quasar emission from that of the host galaxy via spectral energy distribution (SED) fitting. We find evidence for a relatively unobscured, star-forming host galaxy in at least ten quasars, with a further three quasars exhibiting emission consistent with either star formation or scattered light. From the rest-frame UV emission, we derive instantaneous, dust-corrected star formation rates (SFRs) in the range 25 < SFR$_{\rm{UV}}$ < 365 M$_{\odot}$yr$^{-1}$, with an average SFR$_{\rm{UV}}$ = 130 $\pm$ 95 M$_{\odot}$yr$^{-1}$. We find a broad correlation between SFR$_{\rm{UV}}$ and the bolometric quasar luminosity. Overall, our results show evidence for coeval star formation and black hole accretion occurring in luminous, reddened quasars at the peak epoch of galaxy formation., Comment: 21 pages, 8 figures, MNRAS Accepted
Published: 2018
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22. Dark Energy Survey Year 1 Results: Calibration of redMaGiC Redshift Distributions in DES and SDSS from Cross-Correlations

Author: Cawthon, R., Davis, C., Gatti, M., Vielzeuf, P., Elvin-Poole, J., Rozo, E., Frieman, J., Rykoff, E. S., Alarcon, A., Bernstein, G. M., Bonnett, C., Rosell, A. Carnero, Castander, F. J., Chang, C., da Costa, L. N., De Vicente, J., DeRose, J., Drlica-Wagner, A., Gaztanaga, E., Giannantonio, T., Gruen, D., Gschwend, J., Hartley, W. G., Hoyle, B., Lin, H., Maia, M. A. G., Miquel, R., Ogando, R. L. C., Rau, M. M., Roodman, A., Ross, A. J., Sevilla-Noarbe, I., Troxel, M. A., Wechsler, R. H., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Avila, S., Banerji, M., Bechtol, K., Bernstein, R. A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Evrard, A. E., Flaugher, B., Fosalba, P., García-Bellido, J., Gerdes, D. W., Gruendl, R. A., Gutierrez, G., Hollowood, D., Honscheid, K., James, D. J., Jeltema, T., Krause, E., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Marshall, J. L., Martini, P., Menanteau, F., Miller, C. J., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sheldon, E., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Tucker, D. L., and Walker, A. R.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present calibrations of the redshift distributions of redMaGiC galaxies in the Dark Energy Survey Year 1 (DES Y1) and Sloan Digital Sky Survey (SDSS) DR8 data. These results determine the priors of the redshift distribution of redMaGiC galaxies, which were used for galaxy clustering measurements and as lenses for galaxy-galaxy lensing measurements in DES Y1 cosmological analyses. We empirically determine the bias in redMaGiC photometric redshift estimates using angular cross-correlations with Baryon Oscillation Spectroscopic Survey (BOSS) galaxies. For DES, we calibrate a single parameter redshift bias in three photometric redshift bins: $z \in[0.15,0.3]$, [0.3,0.45], and [0.45,0.6]. Our best fit results in each bin give photometric redshift biases of $|\Delta z|<0.01$. To further test the redMaGiC algorithm, we apply our calibration procedure to SDSS redMaGiC galaxies, where the statistical precision of the cross-correlation measurement is much higher due to a greater overlap with BOSS galaxies. For SDSS, we also find best fit results of $|\Delta z|<0.01$. We compare our results to other analyses of redMaGiC photometric redshifts., Comment: 18 pages, 12 figures. Minor changes to text to match version accepted by MNRAS
Published: 2017
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23. Dark Energy Survey Year 1 Results: Measurement of the Baryon Acoustic Oscillation scale in the distribution of galaxies to redshift 1

Author: The Dark Energy Survey Collaboration, Abbott, T. M. C., Abdalla, F. B., Alarcon, A., Allam, S., Andrade-Oliveira, F., Annis, J., Avila, S., Banerji, M., Banik, N., Bechtol, K., Bernstein, G. M., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Camacho, H., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cawthon, R., Chan, K. C., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Drlica-Wagner, A., Eifler, T. F., Elvin-Poole, J., Estrada, J., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Hollowood, D., Honscheid, K., Hoyle, B., Jain, B., James, D. J., Jeltema, T., Johnson, M. D., Kent, S., Kokron, N., Krause, E., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lacasa, F., Lahav, O., Lima, M., Lin, H., Maia, M. A. G., Manera, M., Marriner, J., Marshall, J. L., Martini, P., Melchior, P., Menanteau, F., Miller, C. J., Miquel, R., Mohr, J. J., Neilsen, E., Percival, W. J., Plazas, A. A., Porredon, A., Romer, A. K., Roodman, A., Rosenfeld, R., Ross, A. J., Rozo, E., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schindler, R., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Sheldon, E., Smith, R. C., Smith, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Troxel, M. A., Tucker, D. L., Vikram, V., Walker, A. R., Wechsler, R. H., Weller, J., Yanny, B., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present angular diameter distance measurements obtained by locating the BAO scale in the distribution of galaxies selected from the first year of Dark Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1318 deg$^2$ with $0.6 < z_{\rm photo} < 1$ and a typical redshift uncertainty of $0.03(1+z)$. This sample was selected, as fully described in a companion paper, using a color/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the co-moving transverse separation, and spherical harmonics. Further, we compare results obtained from template based and machine learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, $D_A$, at the effective redshift of our sample divided by the true physical scale of the BAO feature, $r_{\rm d}$. We obtain close to a 4 per cent distance measurement of $D_A(z_{\rm eff}=0.81)/r_{\rm d} = 10.75\pm 0.43 $. These results are consistent with the flat $\Lambda$CDM concordance cosmological model supported by numerous other recent experimental results. All data products are publicly available here: https://des.ncsa.illinois.edu/releases/y1a1/bao, Comment: accepted by MNRAS; main results unchanged, some restructuring, clarifications, and robustness tests added based on referee's comments; all data products are publicly available here: https://des.ncsa.illinois.edu/releases/y1a1/bao
Published: 2017
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24. KELT-21b: A Hot Jupiter Transiting the Rapidly-Rotating Metal-Poor Late-A Primary of a Likely Hierarchical Triple System

Author: Johnson, Marshall C., Rodriguez, Joseph E., Zhou, George, Gonzales, Erica J., Cargile, Phillip A., Crepp, Justin R., Penev, Kaloyan, Stassun, Keivan G., Gaudi, B. Scott, Colón, Knicole D., Stevens, Daniel J., Strassmeier, Klaus G., Ilyin, Ilya, Collins, Karen A., Kielkopf, John F., Oberst, Thomas E., Maritch, Luke, Reed, Phillip A., Gregorio, Joao, Bozza, Valerio, Novati, Sebastiano Calchi, D'Ago, Giuseppe, Scarpetta, Gaetano, Zambelli, Roberto, Latham, David W., Bieryla, Allyson, Cochran, William D., Endl, Michael, Tayar, Jamie, Serenelli, Aldo, Aguirre, Victor Silva, Clarke, Seth P., Martinez, Maria, Spencer, Michelle, Trump, Jason, Joner, Michael D., Bugg, Adam G., Hintz, Eric G., Stephens, Denise C., Arredondo, Anicia, Benzaid, Anissa, Yazdi, Sormeh, McLeod, Kim K., Jensen, Eric L. N., Hancock, Daniel A., Sorber, Rebecca L., Kasper, David H., Jang-Condell, Hannah, Beatty, Thomas G., Carroll, Thorsten, Eastman, Jason, James, David, Kuhn, Rudolf B., Labadie-Bartz, Jonathan, Lund, Michael B., Mallonn, Matthias, Pepper, Joshua, Siverd, Robert J., Yao, Xinyu, Cohen, David H., Curtis, Ivan A., DePoy, D. L., Fulton, Benjamin J., Penny, Matthew T., Relles, Howard, Stockdale, Christopher, Tan, Thiam-Guan, and Villanueva Jr, Steven
Subjects: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We present the discovery of KELT-21b, a hot Jupiter transiting the $V=10.5$ A8V star HD 332124. The planet has an orbital period of $P=3.6127647\pm0.0000033$ days and a radius of $1.586_{-0.040}^{+0.039}$ $R_J$. We set an upper limit on the planetary mass of $M_P<3.91$ $M_J$ at $3\sigma$ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of $\lambda=-5.6_{-1.9}^{+1.7 \circ}$. The star has $T_{\mathrm{eff}}=7598_{-84}^{+81}$ K, $M_*=1.458_{-0.028}^{+0.029}$ $M_{\odot}$, $R_*=1.638\pm0.034$ $R_{\odot}$, and $v\sin I_*=146$ km s$^{-1}$, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal-poor and $\alpha$-enhanced, with [Fe/H]$=-0.405_{-0.033}^{+0.032}$ and [$\alpha$/Fe]$=0.145 \pm 0.053$; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.2" and with a combined contrast of $\Delta K_S=6.39 \pm 0.06$ with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of $\sim0.12$ $M_{\odot}$, a projected mutual separation of $\sim20$ AU, and a projected separation of $\sim500$ AU from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems., Comment: Accepted for publication in AJ. Updated to match accepted version. 25 pages, 14 figures
Published: 2017
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25. Evidence for Dynamically Driven Formation of the GW170817 Neutron Star Binary in NGC 4993

Author: Palmese, A., Hartley, W., Tarsitano, F., Conselice, C., Lahav, O., Allam, S., Annis, J., Lin, H., Soares-Santos, M., Tucker, D., Brout, D., Banerji, M., Bechtol, K., Diehl, H. T., Fruchter, A., Garcia-Bellido, J., Herner, K., Levan, A. J., Li, T. S., Lidman, C., Misra, K., Sako, M., Scolnic, D., Smith, M., Abbott, T. M. C., Abdalla, F. B., Benoit-Levy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Dietrich, J. P., Doel, P., Drlica-Wagner, A., Eifler, T. F., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., Jain, B., James, D. J., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Krause, E., Kron, R., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., McMahon, R. G., Menanteau, F., Miller, C. J., Miquel, R., Neilsen, E., Ogando, R. L. C., Plazas, A. A., Reil, K., Romer, A. K., Sanchez, E., Schindler, R., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Thomas, R. C., Walker, A. R., Weller, J., Zhang, Y., and Zuntz, J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We present a study of NGC 4993, the host galaxy of the GW170817 gravitational wave event, the GRB170817A short gamma-ray burst (sGRB) and the AT2017gfo kilonova. We use Dark Energy Camera imaging, AAT spectra and publicly available data, relating our findings to binary neutron star (BNS) formation scenarios and merger delay timescales. NGC4993 is a nearby (40 Mpc) early-type galaxy, with $i$-band S\'ersic index $n=4.0$ and low asymmetry ($A=0.04\pm 0.01$). These properties are unusual for sGRB hosts. However, NGC4993 presents shell-like structures and dust lanes indicative of a recent galaxy merger, with the optical transient located close to a shell. We constrain the star formation history (SFH) of the galaxy assuming that the galaxy merger produced a star formation burst, but find little to no on-going star formation in either spatially-resolved broadband SED or spectral fitting. We use the best-fit SFH to estimate the BNS merger rate in this type of galaxy, as $R_{NSM}^{gal}= 5.7^{+0.57}_{-3.3} \times 10^{-6} {\rm yr}^{-1}$. If star formation is the only considered BNS formation scenario, the expected number of BNS mergers from early-type galaxies detectable with LIGO during its first two observing seasons is $0.038^{+0.004}_{-0.022}$, as opposed to $\sim 0.5$ from all galaxy types. Hypothesizing that the binary system formed due to dynamical interactions during the galaxy merger, the subsequent time elapsed can constrain the delay time of the BNS coalescence. By using velocity dispersion estimates and the position of the shells, we find that the galaxy merger occurred $t_{\rm mer}\lesssim 200~{\rm Myr}$ prior to the BNS coalescence., Comment: 9 pages, 4 figures, 1 table. Edited to match the ApJL version
Published: 2017
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26. A gravitational-wave standard siren measurement of the Hubble constant

Author: Abbott, B. P., Abbott, R., Abbott, T. D., Acernese, F., Ackley, K., Adams, C., Adams, T., Addesso, P., Adhikari, R. X., Adya, V. B., Affeldt, C., Afrough, M., Agarwal, B., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., Allen, B., Allen, G., Allocca, A., Altin, P. A., Amato, A., Ananyeva, A., Anderson, S. B., Anderson, W. G., Angelova, S. V., Antier, S., Appert, S., Arai, K., Araya, M. C., Areeda, J. S., Arnaud, N., Arun, K. G., Ascenzi, S., Ashton, G., Ast, M., Aston, S. M., Astone, P., Atallah, D. V., Aufmuth, P., Aulbert, C., AultONeal, K., Austin, C., Avila-Alvarez, A., Babak, S., Bacon, P., Bader, M. K. M., Bae, S., Baker, P. T., Baldaccini, F., Ballardin, G., Ballmer, S. W., Banagiri, S., Barayoga, J. C., Barclay, S. E., Barish, B. C., Barker, D., Barkett, K., Barone, F., Barr, B., Barsotti, L., Barsuglia, M., Barta, D., Bartlett, J., Bartos, I., Bassiri, R., Basti, A., Batch, J. C., Bawaj, M., Bayley, J. C., Bazzan, M., Bécsy, B., Beer, C., Bejger, M., Belahcene, I., Bell, A. S., Berger, B. K., Bergmann, G., Bero, J. J., Berry, C. P. L., Bersanetti, D., Bertolini, A., Betzwieser, J., Bhagwat, S., Bhandare, R., Bilenko, I. A., Billingsley, G., Billman, C. R., Birch, J., Birney, R., Birnholtz, O., Biscans, S., Biscoveanu, S., Bisht, A., Bitossi, M., Biwer, C., Bizouard, M. A., Blackburn, J. K., Blackman, J., Blair, C. D., Blair, D. G., Blair, R. M., Bloemen, S., Bock, O., Bode, N., Boer, M., Bogaert, G., Bohe, A., Bondu, F., Bonilla, E., Bonnand, R., Boom, B. A., Bork, R., Boschi, V., Bose, S., Bossie, K., Bouffanais, Y., Bozzi, A., Bradaschia, C., Brady, P. R., Branchesi, M., Brau, J. E., Briant, T., Brillet, A., Brinkmann, M., Brisson, V., Brockill, P., Broida, J. E., Brooks, A. F., Brown, D. A., Brown, D. D., Brunett, S., Buchanan, C. C., Buikema, A., Bulik, T., Bulten, H. J., Buonanno, A., Buskulic, D., Buy, C., Byer, R. L., Cabero, M., Cadonati, L., Cagnoli, G., Cahillane, C., Bustillo, J. Calderón, Callister, T. A., Calloni, E., Camp, J. B., Canepa, M., Canizares, P., Cannon, K. C., Cao, H., Cao, J., Capano, C. D., Capocasa, E., Carbognani, F., Caride, S., Carney, M. F., Diaz, J. Casanueva, Casentini, C., Caudill, S., Cavaglià, M., Cavalier, F., Cavalieri, R., Cella, G., Cepeda, C. B., Cerdá-Durán, P., Cerretani, G., Cesarini, E., Chamberlin, S. J., Chan, M., Chao, S., Charlton, P., Chase, E., Chassande-Mottin, E., Chatterjee, D., Chatziioannou, K., Cheeseboro, B. D., Chen, H. Y., Chen, X., Chen, Y., Cheng, H. -P., Chia, H., Chincarini, A., Chiummo, A., Chmiel, T., Cho, H. S., Cho, M., Chow, J. H., Christensen, N., Chu, Q., Chua, A. J. K., Chua, S., Chung, A. K. W., Chung, S., Ciani, G., Ciolfi, R., Cirelli, C. E., Cirone, A., Clara, F., Clark, J. A., Clearwater, P., Cleva, F., Cocchieri, C., Coccia, E., Cohadon, P. -F., Cohen, D., Colla, A., Collette, C. G., Cominsky, L. 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Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The detection of GW170817 in both gravitational waves and electromagnetic waves heralds the age of gravitational-wave multi-messenger astronomy. On 17 August 2017 the Advanced LIGO and Virgo detectors observed GW170817, a strong signal from the merger of a binary neutron-star system. Less than 2 seconds after the merger, a gamma-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within $\sim 10$ arcsec of the galaxy NGC 4993. These multi-messenger observations allow us to use GW170817 as a standard siren, the gravitational-wave analog of an astronomical standard candle, to measure the Hubble constant. This quantity, which represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Our measurement combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using electromagnetic data. This approach does not require any form of cosmic "distance ladder;" the gravitational wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be $70.0^{+12.0}_{-8.0} \, \mathrm{km} \, \mathrm{s}^{-1} \, \mathrm{Mpc}^{-1}$ (maximum a posteriori and 68% credible interval). This is consistent with existing measurements, while being completely independent of them. Additional standard-siren measurements from future gravitational-wave sources will provide precision constraints of this important cosmological parameter., Comment: 26 pages, 5 figures, Nature in press. For more information see https://dcc.ligo.org/LIGO-P1700296/public
Published: 2017
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27. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. II. UV, Optical, and Near-IR Light Curves and Comparison to Kilonova Models

Author: Cowperthwaite, P. S., Berger, E., Villar, V. A., Metzger, B. D., Nicholl, M., Chornock, R., Blanchard, P. K., Fong, W., Margutti, R., Soares-Santos, M., Alexander, K. D., Allam, S., Annis, J., Brout, D., Brown, D. A., Butler, R. E., Chen, H. -Y., Diehl, H. T., Doctor, Z., Drout, M. R., Eftekhari, T., Farr, B., Finley, D. A., Foley, R. J., Frieman, J. A., Fryer, C. L., García-Bellido, J., Gill, M. S. S., Guillochon, J., Herner, K., Holz, D. E., Kasen, D., Kessler, R., Marriner, J., Matheson, T., Neilsen, Jr., E. H., Quataert, E., Palmese, A., Rest, A., Sako, M., Scolnic, D. M., Smith, N., Tucker, D. L., Williams, P. K. G., Balbinot, E., Carlin, J. L., Cook, E. R., Durret, F., Li, T. S., Lopes, P. A. A., Lourenço, A. C. C., Marshall, J. L., Medina, G. E., Muir, J., Muñoz, R. R., Sauseda, M., Schlegel, D. J., Secco, L. F., Vivas, A. K., Wester, W., Zenteno, A., Zhang, Y., Abbott, T. M. C., Banerji, M., Bechtol, K., Benoit-Lévy, A., Bertin, E., Buckley-Geer, E., Burke, D. L., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Castander, F. J., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Dietrich, J. P., Drlica-Wagner, A., Eifler, T. F., Evrard, A. E., Fernandez, E., Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D. J., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Kent, S., Krause, E., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Lin, H., Maia, M. A. G., March, M., Martini, P., McMahon, R. G., Menanteau, F., Miller, C. J., Miquel, R., Mohr, J. J., Neilsen, E., Nichol, R. C., Ogando, R. L. C., Plazas, A. A., Roe, N., Romer, A. K., Roodman, A., Rykoff, E. S., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Thomas, R. C., Troxel, M. A., Vikram, V., Walker, A. R., Wechsler, R. H., Weller, J., Yanny, B., and Zuntz, J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present UV, optical, and NIR photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced LIGO/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at $0.47$ days to $18.5$ days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), and the {\it Hubble Space Telescope} ({\it HST}). The spectral energy distribution (SED) inferred from this photometry at $0.6$ days is well described by a blackbody model with $T\approx 8300$ K, a radius of $R\approx 4.5\times 10^{14}$ cm (corresponding to an expansion velocity of $v\approx 0.3c$), and a bolometric luminosity of $L_{\rm bol}\approx 5\times10^{41}$ erg s$^{-1}$. At $1.5$ days we find a multi-component SED across the optical and NIR, and subsequently we observe rapid fading in the UV and blue optical bands and significant reddening of the optical/NIR colors. Modeling the entire data set we find that models with heating from radioactive decay of $^{56}$Ni, or those with only a single component of opacity from $r$-process elements, fail to capture the rapid optical decline and red optical/NIR colors. Instead, models with two components consistent with lanthanide-poor and lanthanide-rich ejecta provide a good fit to the data, the resulting "blue" component has $M_\mathrm{ej}^\mathrm{blue}\approx 0.01$ M$_\odot$ and $v_\mathrm{ej}^\mathrm{blue}\approx 0.3$c, and the "red" component has $M_\mathrm{ej}^\mathrm{red}\approx 0.04$ M$_\odot$ and $v_\mathrm{ej}^\mathrm{red}\approx 0.1$c. These ejecta masses are broadly consistent with the estimated $r$-process production rate required to explain the Milky Way $r$-process abundances, providing the first evidence that BNS mergers can be a dominant site of $r$-process enrichment., Comment: 13 Pages, 3 Figures, 2 Tables. ApJL, In Press. Keywords: GW170817, LVC
Published: 2017
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28. Observations of the first electromagnetic counterpart to a gravitational wave source by the TOROS collaboration

Author: Díaz, M. C., Macri, L. M., Lambas, D. Garcia, de Oliveira, C. Mendes, Castellón, J. L. Nilo, Ribeiro, T., Sánchez, B., Schoenell, W., Abramo, L. R., Akras, S., Alcaniz, J. S., Artola, R., Beroiz, M., Bonoli, S., Cabral, J., Camuccio, R., Castillo, M., Chavushyan, V., Coelho, P., Colazo, C., Costa-Duarte, M. V., Larenas, H. Cuevas, DePoy, D. L., Romero, M. Domínguez, Dultzin, D., Fernández, D., García, J., Girardini, C., Gonçalves, D. R., Gonçalves, T. S., Gurovich, S., Jiménez-Teja, Y., Kanaan, A., Lares, M., de Oliveira, R. Lopes, López-Cruz, O., Marshall, J. L., Melia, R., Molino, A., Padilla, N., Peñuela, T., Placco, V. M., Quiñones, C., Rivera, A. Ramírez, Renzi, V., Riguccini, L., Ríos-López, E., Rodriguez, H., Sampedro, L., Schneiter, M., Sodré, L., Starck, M., Torres-Flores, S., Tornatore, M., and Zadrożny, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration (TOROS). We detected highly significant dimming in the light curves of the counterpart (Delta g=0.17+-0.03 mag, Delta r=0.14+-0.02 mag, Delta i=0.10 +- 0.03 mag) over the course of only 80 minutes of observations obtained ~35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ~59 hr after the event with the EABA 1.5m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a "blue kilonova" relatively free of lanthanides., Comment: Accepted for publication in The Astrophysical Journal Letters
Published: 2017
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29. The Carnegie Supernova Project I: Third Photometry Data Release of Low-Redshift Type Ia Supernovae and Other White Dwarf Explosions

Author: Krisciunas, Kevin, Contreras, Carlos, Burns, Christopher R., Phillips, M. M., Stritzinger, Maximilian D., Morrell, Nidia, Hamuy, Mario, Anais, Jorge, Boldt, Luis, Busta, Luis, Campillay, Abdo, Castellon, Sergio, Folatelli, Gaston, Freedman, Wendy L., Gonzalez, Consuelo, Hsiao, Eric. Y., Krzeminski, Wojtek, Persson, Sven Eric, Roth, Miguel, Salgado, Francisco, Seron, Jacqueline, Suntzeff, Nicholas B., Torres, Simon, Filippenko, Alexei V., Li, Weidong, Madore, Barry F., DePoy, D. L., Marshall, Jennifer L., Rheault, Jean-Philippe, and Villanueva, Steven
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present final natural system optical (ugriBV) and near-infrared (YJH) photometry of 134 supernovae (SNe) with probable white dwarf progenitors that were observed in 2004-2009 as part of the first stage of the Carnegie Supernova Project (CSP-I). The sample consists of 123 Type Ia SNe, 5 Type Iax SNe, 2 super-Chandrasekhar SN candidates, 2 Type Ia SNe interacting with circumstellar matter, and 2 SN 2006bt-like events. The redshifts of the objects range from z = 0.0037 to 0.0835; the median redshift is 0.0241. For 120 (90%) of these SNe, near-infrared photometry was obtained. Average optical extinction coefficients and color terms are derived and demonstrated to be stable during the five CSP-I observing campaigns. Measurements of the CSP-I near-infrared bandpasses are also described, and near-infrared color terms are estimated through synthetic photometry of stellar atmosphere models. Optical and near-infrared magnitudes of local sequences of tertiary standard stars for each supernova are given, and a new calibration of Y-band magnitudes of the Persson et al. (1998) standards in the CSP-I natural system is presented., Comment: 95 pages, 50 figures, published in Astronomical Journal, vol. 154, article 211 (November 2017). The full online version contains 114 more finder charts and 119 more light curve plots. Version 2 of this preprint has an updated Table 3, additional references, and two updated light curve plots. Version 3 has updated Table 4
Published: 2017
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30. Dark Energy Survey Year 1 Results: Cross-Correlation Redshifts - Methods and Systematics Characterization

Author: Gatti, M., Vielzeuf, P., Davis, C., Cawthon, R., Rau, M. M., DeRose, J., De Vicente, J., Alarcon, A., Rozo, E., Gaztanaga, E., Hoyle, B., Miquel, R., Bernstein, G. M., Bonnett, C., Rosell, A. Carnero, Castander, F. J., Chang, C., da Costa, L. N., Gruen, D., Gschwend, J., Hartley, W. G., Lin, H., MacCrann, N., Maia, M. A. G., Ogando, R. L. C., Roodman, A., Sevilla-Noarbe, I., Troxel, M. A., Wechsler, R. H., Asorey, J., Davis, T. M., Glazebrook, K., Hinton, S. R., Lewis, G., Lidman, C., Macaulay, E., Möller, A., O'Neill, C. R., Sommer, N. E., Uddin, S. A., Yuan, F., Zhang, B., Abbott, T. M. C., Allam, S., Annis, J., Bechtol, K., Brooks, D., Burke, D. L., Carollo, D., Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., DePoy, D. L., Desai, S., Eifler, T. F., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Goldstein, D. A., Gruendl, R. A., Gutierrez, G., Honscheid, K., Hoormann, J. K., Jain, B., James, D. J., Jarvis, M., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Krause, E., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Li, T. S., Lima, M., Marshall, J. L., Melchior, P., Menanteau, F., Nichol, R. C., Nord, B., Plazas, A. A., Reil, K., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Sheldon, E., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Tucker, B. E., Tucker, D. L., Vikram, V., Walker, A. R., Weller, J., Wester, W., and Wolf, R. C.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1 (DES Y1) sample with redMaGiC galaxies (luminous red galaxies with secure photometric redshifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-$z$ methods applied to the same source galaxy sample. We apply the method to three photo-$z$ codes run in our simulated data: Bayesian Photometric Redshift (BPZ), Directional Neighborhood Fitting (DNF), and Random Forest-based photo-$z$ (RF). We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering vs photo-$z$'s. The systematic uncertainty in the mean redshift bias of the source galaxy sample is $\Delta z \lesssim 0.02$, though the precise value depends on the redshift bin under consideration. We discuss possible ways to mitigate the impact of our dominant systematics in future analyses., Comment: submitted to MNRAS
Published: 2017
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31. Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I

Author: Nagasawa, D. Q., Marshall, J. L., Simon, J. D., Hansen, T. T., Li, T. S., Bernstein, R. A., Balbinot, E., Drlica-Wagner, A., Pace, A. B., Strigari, L. E., Pellegrino, C. M., DePoy, D. L., Suntzeff, N. B., Bechtol, K., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Benoit-Lévy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Davis, C., Desai, S., Doel, P., Eifler, T. F., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hartley, W. G., Honscheid, K., James, D. J., Jeltema, T., Krause, E., Kuehn, K., Kuhlmann, S., Kuropatkin, N., March, M., Miquel, R., Nord, B., Roodman, A., Sanchez, E., Santiago, B., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., Tucker, D. L., Walker, A. R., Wechsler, R. H., Wolf, R. C., and Yanny, B.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We present chemical abundance measurements of three stars in the ultra-faint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high resolution spectroscopic observations we measure the metallicity of the three stars as well as abundance ratios of several $\alpha$-elements, iron-peak elements, and neutron-capture elements. The abundance pattern is relatively consistent among all three stars, which have a low average metallicity of [Fe/H] $\sim -2.6$ and are not $\alpha$-enhanced ([$\alpha$/Fe] $\sim 0.0$). This result is unexpected when compared to other low-metallicity stars in the Galactic halo and other ultra-faint dwarfs and hints at an entirely different mechanism for the enrichment of Hor I compared to other satellites. We discuss possible scenarios that could lead to this observed nucleosynthetic signature including extended star formation, a Population III supernova, and a possible association with the Large Magellanic Cloud.
Published: 2017
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32. Dark Energy Survey Year 1 Results: Cosmological Constraints from Cosmic Shear

Author: Troxel, M. A., MacCrann, N., Zuntz, J., Eifler, T. F., Krause, E., Dodelson, S., Gruen, D., Blazek, J., Friedrich, O., Samuroff, S., Prat, J., Secco, L. F., Davis, C., Ferté, A., DeRose, J., Alarcon, A., Amara, A., Baxter, E., Becker, M. R., Bernstein, G. M., Bridle, S. L., Cawthon, R., Chang, C., Choi, A., De Vicente, J., Drlica-Wagner, A., Elvin-Poole, J., Frieman, J., Gatti, M., Hartley, W. G., Honscheid, K., Hoyle, B., Huff, E. M., Huterer, D., Jain, B., Jarvis, M., Kacprzak, T., Kirk, D., Kokron, N., Krawiec, C., Lahav, O., Liddle, A. R., Peacock, J., Rau, M. M., Refregier, A., Rollins, R. P., Rozo, E., Rykoff, E. S., Sánchez, C., Sevilla-Noarbe, I., Sheldon, E., Stebbins, A., Varga, T. N., Vielzeuf, P., Wang, M., Wechsler, R. H., Yanny, B., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Dietrich, J. P., Doel, P., Fernandez, E., Flaugher, B., Fosalba, P., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Goldstein, D. A., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Kent, S., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Li, T. S., Lima, M., Lin, H., Maia, M. A. G., March, M., Marshall, J. L., Martini, P., Melchior, P., Menanteau, F., Miquel, R., Mohr, J. J., Neilsen, E., Nichol, R. C., Nord, B., Petravick, D., Plazas, A. A., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Tucker, D. L., Vikram, V., Walker, A. R., Weller, J., and Zhang, Y.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We use 26 million galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg$^2$ of the sky to produce the most significant measurement of cosmic shear in a galaxy survey to date. We constrain cosmological parameters in both the flat $\Lambda$CDM and $w$CDM models, while also varying the neutrino mass density. These results are shown to be robust using two independent shape catalogs, two independent \photoz\ calibration methods, and two independent analysis pipelines in a blind analysis. We find a 3.5\% fractional uncertainty on $\sigma_8(\Omega_m/0.3)^{0.5} = 0.782^{+0.027}_{-0.027}$ at 68\% CL, which is a factor of 2.5 improvement over the fractional constraining power of our DES Science Verification results. In $w$CDM, we find a 4.8\% fractional uncertainty on $\sigma_8(\Omega_m/0.3)^{0.5} = 0.777^{+0.036}_{-0.038}$ and a dark energy equation-of-state $w=-0.95^{+0.33}_{-0.39}$. We find results that are consistent with previous cosmic shear constraints in $\sigma_8$ -- $\Omega_m$, and see no evidence for disagreement of our weak lensing data with data from the CMB. Finally, we find no evidence preferring a $w$CDM model allowing $w\ne -1$. We expect further significant improvements with subsequent years of DES data, which will more than triple the sky coverage of our shape catalogs and double the effective integrated exposure time per galaxy., Comment: 32 pages, 19 figures; matches PRD referee response version
Published: 2017
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33. Dark Energy Survey Year 1 Results: Redshift distributions of the weak lensing source galaxies

Author: Hoyle, B., Gruen, D., Bernstein, G. M., Rau, M. M., De Vicente, J., Hartley, W. G., Gaztanaga, E., DeRose, J., Troxel, M. A., Davis, C., Alarcon, A., MacCrann, N., Prat, J., Sánchez, C., Sheldon, E., Wechsler, R. H., Asorey, J., Becker, M. R., Bonnett, C., Rosell, A. Carnero, Carollo, D., Kind, M. Carrasco, Castander, F. J., Cawthon, R., Chang, C., Childress, M., Davis, T. M., Drlica-Wagner, A., Gatti, M., Glazebrook, K., Gschwend, J., Hinton, S. R., Hoormann, J. K., Kim, A. G., King, A., Kuehn, K., Lewis, G., Lidman, C., Lin, H., Macaulay, E., Maia, M. A. G., Martini, P., Mudd, D., Möller, A., Nichol, R. C., Ogando, R. L. C., Rollins, R. P., Roodman, A., Ross, A. J., Rozo, E., Rykoff, E. S., Samuroff, S., Sevilla-Noarbe, I., Sharp, R., Sommer, N. E., Tucker, B. E., Uddin, S. A., Varga, T. N., Vielzeuf, P., Yuan, F., Zhang, B., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Busha, M. T., Capozzi, D., Carretero, J., Crocce, M., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Estrada, J., Evrard, A. E., Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Giannantonio, T., Goldstein, D. A., Gruendl, R. A., Gutierrez, G., Honscheid, K., James, D. J., Jarvis, M., Jeltema, T., Johnson, M. W. G., Johnson, M. D., Kirk, D., Krause, E., Kuhlmann, S., Kuropatkin, N., Lahav, O., Li, T. S., Lima, M., March, M., Marshall, J. L., Melchior, P., Menanteau, F., Miquel, R., Nord, B., O'Neill, C. R., Plazas, A. A., Romer, A. K., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schindler, R., Schubnell, M., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Tucker, D. L., Vikram, V., Walker, A. R., Weller, J., Wester, W., Wolf, R. C., Yanny, B., and Zuntz, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z=0.2 and 1.3, and to produce initial estimates of the lensing-weighted redshift distributions $n^i_{PZ}(z)$ for bin i. Accurate determination of cosmological parameters depends critically on knowledge of $n^i$ but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts $n^i(z)=n^i_{PZ}(z-\Delta z^i)$ to correct the mean redshift of $n^i(z)$ for biases in $n^i_{\rm PZ}$. The $\Delta z^i$ are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the COSMOS field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the $\Delta z^i$ are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15
Published: 2017
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34. Dark Energy Survey Year 1 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing

Author: DES Collaboration, Abbott, T. M. C., Abdalla, F. B., Alarcon, A., Aleksić, J., Allam, S., Allen, S., Amara, A., Annis, J., Asorey, J., Avila, S., Bacon, D., Balbinot, E., Banerji, M., Banik, N., Barkhouse, W., Baumer, M., Baxter, E., Bechtol, K., Becker, M. R., Benoit-Lévy, A., Benson, B. A., Bernstein, G. M., Bertin, E., Blazek, J., Bridle, S. L., Brooks, D., Brout, D., Buckley-Geer, E., Burke, D. L., Busha, M. T., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Castander, F. J., Cawthon, R., Chang, C., Chen, N., Childress, M., Choi, A., Conselice, C., Crittenden, R., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Das, R., Davis, T. M., Davis, C., De Vicente, J., DePoy, D. L., DeRose, J., Desai, S., Diehl, H. T., Dietrich, J. P., Dodelson, S., Doel, P., Drlica-Wagner, A., Eifler, T. F., Elliott, A. E., Elsner, F., Elvin-Poole, J., Estrada, J., Evrard, A. E., Fang, Y., Fernandez, E., Ferté, A., Finley, D. A., Flaugher, B., Fosalba, P., Friedrich, O., Frieman, J., García-Bellido, J., Garcia-Fernandez, M., Gatti, M., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Gill, M. S. S., Glazebrook, K., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hamilton, S., Hartley, W. G., Hinton, S. R., Honscheid, K., Hoyle, B., Huterer, D., Jain, B., James, D. J., Jarvis, M., Jeltema, T., Johnson, M. D., Johnson, M. W. G., Kacprzak, T., Kent, S., Kim, A. G., King, A., Kirk, D., Kokron, N., Kovacs, A., Krause, E., Krawiec, C., Kremin, A., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lacasa, F., Lahav, O., Li, T. S., Liddle, A. R., Lidman, C., Lima, M., Lin, H., MacCrann, N., Maia, M. A. G., Makler, M., Manera, M., March, M., Marshall, J. L., Martini, P., McMahon, R. G., Melchior, P., Menanteau, F., Miquel, R., Miranda, V., Mudd, D., Muir, J., Möller, A., Neilsen, E., Nichol, R. C., Nord, B., Nugent, P., Ogando, R. L. C., Palmese, A., Peacock, J., Peiris, H. V., Peoples, J., Percival, W. J., Petravick, D., Plazas, A. A., Porredon, A., Prat, J., Pujol, A., Rau, M. M., Refregier, A., Ricker, P. M., Roe, N., Rollins, R. P., Romer, A. K., Roodman, A., Rosenfeld, R., Ross, A. J., Rozo, E., Rykoff, E. S., Sako, M., Salvador, A. I., Samuroff, S., Sánchez, C., Sanchez, E., Santiago, B., Scarpine, V., Schindler, R., Scolnic, D., Secco, L. F., Serrano, S., Sevilla-Noarbe, I., Sheldon, E., Smith, R. C., Smith, M., Smith, J., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., Troxel, M. A., Tucker, D. L., Tucker, B. E., Uddin, S. A., Varga, T. N., Vielzeuf, P., Vikram, V., Vivas, A. K., Walker, A. R., Wang, M., Wechsler, R. H., Weller, J., Wester, W., Wolf, R. C., Yanny, B., Yuan, F., Zenteno, A., Zhang, B., Zhang, Y., and Zuntz, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321 deg$^2$ of $griz$ imaging data from the first year of the Dark Energy Survey (DES Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric redshift estimation and validation, and likelihood analysis pipelines. To prevent confirmation bias, the bulk of the analysis was carried out while blind to the true results; we describe an extensive suite of systematics checks performed and passed during this blinded phase. The data are modeled in flat $\Lambda$CDM and $w$CDM cosmologies, marginalizing over 20 nuisance parameters, varying 6 (for $\Lambda$CDM) or 7 (for $w$CDM) cosmological parameters including the neutrino mass density and including the 457 $\times$ 457 element analytic covariance matrix. We find consistent cosmological results from these three two-point functions, and from their combination obtain $S_8 \equiv \sigma_8 (\Omega_m/0.3)^{0.5} = 0.783^{+0.021}_{-0.025}$ and $\Omega_m = 0.264^{+0.032}_{-0.019}$ for $\Lambda$CDM for $w$CDM, we find $S_8 = 0.794^{+0.029}_{-0.027}$, $\Omega_m = 0.279^{+0.043}_{-0.022}$, and $w=-0.80^{+0.20}_{-0.22}$ at 68% CL. The precision of these DES Y1 results rivals that from the Planck cosmic microwave background measurements, allowing a comparison of structure in the very early and late Universe on equal terms. Although the DES Y1 best-fit values for $S_8$ and $\Omega_m$ are lower than the central values from Planck ..., Comment: Matches published version. Results essentially unchanged, except updated covariance matrix leads to improved chi^2 (colored text removed)
Published: 2017
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35. Dark Energy Survey Year 1 Results: Photometric Data Set for Cosmology

Author: Drlica-Wagner, A., Sevilla-Noarbe, I., Rykoff, E. S., Gruendl, R. A., Yanny, B., Tucker, D. L., Hoyle, B., Rosell, A. Carnero, Bernstein, G. M., Bechtol, K., Becker, M. R., Benoit-Levy, A., Bertin, E., Kind, M. Carrasco, Davis, C., de Vicente, J., Diehl, H. T., Gruen, D., Hartley, W. G., Leistedt, B., Li, T. S., Marshall, J. L., Neilsen, E., Rau, M. M., Sheldon, E., Smith, J., Troxel, M. A., Wyatt, S., Zhang, Y., Abbott, T. M. C., Abdalla, F. B., Allam, S., Banerji, M., Brooks, D., Buckley-Geer, E., Burke, D. L., Capozzi, D., Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Dietrich, J. P., Doel, P., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gerdes, D. W., Giannantonio, T., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Jeltema, T., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Lin, H., Maia, M. A. G., Martini, P., McMahon, R. G., Melchior, P., Menanteau, F., Miquel, R., Nichol, R. C., Ogando, R. L. C., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Vikram, V., Walker, A. R., Wechsler, R. H., and Zuntz, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: We describe the creation, content, and validation of the Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support of upcoming cosmological analyses. The Y1A1 GOLD data set is assembled from multiple epochs of DES imaging and consists of calibrated photometric zeropoints, object catalogs, and ancillary data products - e.g., maps of survey depth and observing conditions, star-galaxy classification, and photometric redshift estimates - that are necessary for accurate cosmological analyses. The Y1A1 GOLD wide-area object catalog consists of ~137 million objects detected in coadded images covering ~1800 deg$^2$ in the DES grizY filters. The 10{\sigma} limiting magnitude for galaxies is g = 23.4, r = 23.2, i = 22.5, z = 21.8, and Y = 20.1. Photometric calibration of Y1A1 GOLD was performed by combining nightly zeropoint solutions with stellar-locus regression, and the absolute calibration accuracy is better than 2% over the survey area. DES Y1A1 GOLD is the largest photometric data set at the achieved depth to date, enabling precise measurements of cosmic acceleration at z $\lesssim$ 1., Comment: 43 pages, 28 figures, 8 tables; updated to match published version
Published: 2017
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36. The First Planetary Microlensing Event with Two Microlensed Source Stars

Author: Bennett, D. P., Udalski, A., Han, C., Bond, I. A., Beaulieu, J. -P., Skowron, J., Gaudi, B. S., Koshimoto, N., Abe, F., Asakura, Y., Barry, R. K., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Oyokawa, H., Ranc, C., Rattenbury, N. J., Rosenthal, M. K., Saito, To., Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yonehara, A., Szymanski, M. K., Poleski, R., Soszynski, I., Ulaczyk, K., Wyrzykowski, L., DePoy, D., Gould, A., Pogge, R. W., Yee, J. C., Albrow, M. D., Bachelet, E., Batista, V., Bowens-Rubin, R., Brillant, S., Caldwell, J. A. R., Cole, A., Coutures, C., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouque, P., Horne, K., Hundertmark, M., Kains, N., Kane, S. R., Marquette, J. -B., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., and Zub, M.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the analysis of microlensing event MOA-2010-BLG-117, and show that the light curve can only be explained by the gravitational lensing of a binary source star system by a star with a Jupiter mass ratio planet. It was necessary to modify standard microlensing modeling methods to find the correct light curve solution for this binary-source, binary-lens event. We are able to measure a strong microlensing parallax signal, which yields the masses of the host star, $M_* = 0.58\pm 0.11 M_\odot$, and planet $m_p = 0.54\pm 0.10 M_{\rm Jup}$ at a projected star-planet separation of $a_\perp = 2.42\pm 0.26\,$AU, corresponding to a semi-major axis of $a = 2.9{+1.6\atop -0.6}\,$AU. Thus, the system resembles a half-scale model of the Sun-Jupiter system with a half-Jupiter mass planet orbiting a half-solar mass star at very roughly half of Jupiter's orbital distance from the Sun. The source stars are slightly evolved, and by requiring them to lie on the same isochrone, we can constrain the source to lie in the near side of the bulge at a distance of $D_S = 6.9 \pm 0.7\,$kpc, which implies a distance to the planetary lens system of $D_L = 3.5\pm 0.4\,$kpc. The ability to model unusual planetary microlensing events, like this one, will be necessary to extract precise statistical information from the planned large exoplanet microlensing surveys, such as the WFIRST microlensing survey., Comment: Accepted version. Now published in AJ
Published: 2017
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37. KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603

Author: Lund, Michael B., Rodriguez, Joseph E., Zhou, George, Gaudi, B. Scott, Stassun, Keivan G., Johnson, Marshall C., Bieryla, Allyson, Oelkers, Ryan J., Stevens, Daniel J., Collins, Karen A., Penev, Kaloyan, Quinn, Samuel N., Latham, David W., Villanueva Jr., Steven, Eastman, Jason D., Kielkopf, John F., Oberst, Thomas E., Jensen, Eric L. N., Cohen, David H., Joner, Michael D., Stephens, Denise C., Relles, Howard, Corfini, Giorgio, Gregorio, Joao, Zambelli, Roberto, Esquerdo, Gilbert A., Calkins, Michael L., Berlind, Perry, Ciardi, David R., Dressing, Courtney, Patel, Rahul, Gagnon, Patrick, Gonzales, Erica, Beatty, Thomas G., Siverd, Robert J., Labadie-Bartz, Jonathan, Kuhn, Rudolf B., Colon, Knicole D., James, David, Pepper, Joshua, Fulton, Benjamin J., McLeod, Kim K., Stockdale, Christopher, Novati, Sebastiano Calchi, DePoy, D. L., Gould, Andrew, Marshall, Jennifer L., Trueblood, Mark, and Trueblood, Patricia
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of KELT-20b, a hot Jupiter transiting a V~7.6 early A star with an orbital period of P~3.47 days. We identified the initial transit signal in KELT-North survey data. Archival and follow-up photometry, the Gaia parallax, radial velocities, Doppler tomography, and adaptive optics imaging were used to confirm the planetary nature of the companion and characterize the system. From global modeling we infer that the host star HD 185603 is a rapidly-rotating (VsinI~120 km/s) A2V star with an effective temperature of $T_{eff}$=8730K, mass of $M_{star}=1.76M_{sun}$, radius of $R_{star}=1.561R_{sun}$, surface gravity of logg=4.292, and age of <600 Myr. The planetary companion has a radius of $1.735^{+0.070}_{-0.075}~R_{J}$, a semimajor axis of $a=0.0542^{+0.0014}_{-0.0021}$AU, and a linear ephemeris of $BJD_{TDB}=2457503.120049 \pm 0.000190 + E(3.4741070\pm0.0000019)$. We place a $3\sigma$ upper limit of ~3.5 $M_{J}$ on the mass of the planet. The Doppler tomographic measurement indicates that the planetary orbit is well aligned with the projected spin-axis of the star ($\lambda= 3.4\pm {2.1}$ degrees). The inclination of the star is constrained to be $24.4
Published: 2017
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38. Dark Energy Survey Year 1 Results: Multi-Probe Methodology and Simulated Likelihood Analyses

Author: Krause, E., Eifler, T. F., Zuntz, J., Friedrich, O., Troxel, M. A., Dodelson, S., Blazek, J., Secco, L. F., MacCrann, N., Baxter, E., Chang, C., Chen, N., Crocce, M., DeRose, J., Ferte, A., Kokron, N., Lacasa, F., Miranda, V., Omori, Y., Porredon, A., Rosenfeld, R., Samuroff, S., Wang, M., Wechsler, R. H., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Levy, A., Bernstein, G. M., Brooks, D., Burke, D. L., Capozzi, D., Kind, M. Carrasco, Carretero, J., D'Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Diehl, H. T., Dietrich, J. P., Evrard, A. E., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Giannantonio, T., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Jeltema, T., Kuehn, K., Kuhlmann, S., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., Martini, P., Menanteau, F., Miquel, R., Nichol, R. C., Plazas, A. A., Romer, A. K., Rykoff, E. S., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Tucker, D. L., Vikram, V., Walker, A. R., and Weller, J.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present the methodology for and detail the implementation of the Dark Energy Survey (DES) 3x2pt DES Year 1 (Y1) analysis, which combines configuration-space two-point statistics from three different cosmological probes: cosmic shear, galaxy-galaxy lensing, and galaxy clustering, using data from the first year of DES observations. We have developed two independent modeling pipelines and describe the code validation process. We derive expressions for analytical real-space multi-probe covariances, and describe their validation with numerical simulations. We stress-test the inference pipelines in simulated likelihood analyses that vary 6-7 cosmology parameters plus 20 nuisance parameters and precisely resemble the analysis to be presented in the DES 3x2pt analysis paper, using a variety of simulated input data vectors with varying assumptions. We find that any disagreement between pipelines leads to changes in assigned likelihood $\Delta \chi^2 \le 0.045$ with respect to the statistical error of the DES Y1 data vector. We also find that angular binning and survey mask do not impact our analytic covariance at a significant level. We determine lower bounds on scales used for analysis of galaxy clustering (8 Mpc$~h^{-1}$) and galaxy-galaxy lensing (12 Mpc$~h^{-1}$) such that the impact of modeling uncertainties in the non-linear regime is well below statistical errors, and show that our analysis choices are robust against a variety of systematics. These tests demonstrate that we have a robust analysis pipeline that yields unbiased cosmological parameter inferences for the flagship 3x2pt DES Y1 analysis. We emphasize that the level of independent code development and subsequent code comparison as demonstrated in this paper is necessary to produce credible constraints from increasingly complex multi-probe analyses of current data.
Published: 2017

39. COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408-5354 with high-cadence photometric monitoring

Author: Courbin, F., Bonvin, V., Buckley-Geer, E., Fassnacht, C. D., Frieman, J., Lin, H., Marshall, P. J., Suyu, S. H., Treu, T., Anguita, T., Motta, V., Meylan, G., Paic, E., Tewes, M., Agnello, A., Chao, D. C. -Y., Chijani, M., Gilman, D., Rojas, K., Williams, P., Hempel, A., Kim, S., Lachaume, R., Rabus, M., Abbott, T. M. C., Allam, S., Annis, J., Banerji, M., Bechtol, K., Benoit-Lévy, A., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., D'Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Flaugher, B., Fosalba, P., Garcia-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., McMahon, R. G., Menanteau, F., Miquel, R., Nord, B., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Tucker, D. L., Walker, A. R., and Wester, W.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We present time-delay measurements for the new quadruply imaged quasar DES J0408-5354, the first quadruply imaged quasar found in the Dark Energy Survey (DES). Our result is made possible by implementing a new observational strategy using almost daily observations with the MPIA 2.2m telescope at La Silla observatory and deep exposures reaching a signal-to-noise ratio of about 1000 per quasar image. This data quality allows us to catch small photometric variations (a few mmag rms) of the quasar, acting on temporal scales much shorter than microlensing, hence making the time delay measurement very robust against microlensing. In only 7 months we measure very accurately one of the time delays in DES J0408-5354: Dt(AB) = -112.1 +- 2.1 days (1.8%) using only the MPIA 2.2m data. In combination with data taken with the 1.2m Euler Swiss telescope, we also measure two delays involving the D component of the system Dt(AD) = -155.5 +- 12.8 days (8.2%) and Dt(BD) = -42.4 +- 17.6 days (41%), where all the error bars include systematics. Turning these time delays into cosmological constraints will require deep HST imaging or ground-based Adaptive Optics (AO), and information on the velocity field of the lensing galaxy., Comment: 9 pages, 5 figures, accepted for publication in Astronomy & Astrophysics
Published: 2017
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40. A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host

Author: Gaudi, B. Scott, Stassun, Keivan G., Collins, Karen A., Beatty, Thomas G., Zhou, George, Latham, David W., Bieryla, Allyson, Eastman, Jason D., Siverd, Robert J., Crepp, Justin R., Gonzales, Erica J., Stevens, Daniel J., Buchhave, Lars A., Pepper, Joshua, Johnson, Marshall C., Colon, Knicole D., Jensen, Eric L. N., Rodriguez, Joseph E., Bozza, Valerio, Novati, Sebastiano Calchi, D'Ago, Giuseppe, Dumont, Mary T., Ellis, Tyler, Gaillard, Clement, Jang-Condell, Hannah, Kasper, David H., Fukui, Akihiko, Gregorio, Joao, Ito, Ayaka, Kielkopf, John F., Manner, Mark, Matt, Kyle, Narita, Norio, Oberst, Thomas E., Reed, Phillip A., Scarpetta, Gaetano, Stephens, Denice C., Yeigh, Rex R., Zambelli, Roberto, Fulton, B. J., Howard, Andrew W., James, David J., Penny, Matthew, Bayliss, Daniel, Curtis, Ivan A., DePoy, D. L., Esquerdo, Gilbert A., Gould, Andrew, Joner, Michael D., Kuhn, Rudolf B., Labadie-Bartz, Jonathan, Lund, Michael B., Marshall, Jennifer L., McLeod, Kim K., Pogge, Richard W., Relles, Howard, Stockdale, Chistopher, Tan, T. G., Trueblood, Mark, and Trueblood, Patricia
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extra-solar planets now known, only four giant planets have been found that transit hot, A-type stars (temperatures of 7300-10,000K), and none are known to transit even hotter B-type stars. WASP-33 is an A-type star with a temperature of ~7430K, which hosts the hottest known transiting planet; the planet is itself as hot as a red dwarf star of type M. The planet displays a large heat differential between its day-side and night-side, and is highly inflated, traits that have been linked to high insolation. However, even at the temperature of WASP-33b's day-side, its atmosphere likely resembles the molecule-dominated atmospheres of other planets, and at the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be significantly ablated over the lifetime of its star. Here we report observations of the bright star HD 195689, which reveal a close-in (orbital period ~1.48 days) transiting giant planet, KELT-9b. At ~10,170K, the host star is at the dividing line between stars of type A and B, and we measure the KELT-9b's day-side temperature to be ~4600K. This is as hot as stars of stellar type K4. The molecules in K stars are entirely dissociated, and thus the primary sources of opacity in the day-side atmosphere of KELT-9b are likely atomic metals. Furthermore, KELT-9b receives ~700 times more extreme ultraviolet radiation (wavelengths shorter than 91.2 nanometers) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star., Comment: 39 pages, 3 figures, 1 table, 3 extended data figures, 3 extended data tables. Published in Nature on 22 June 2017
Published: 2017
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41. Astrometric calibration and performance of the Dark Energy Camera

Author: Bernstein, G. M., Armstrong, R., Plazas, A. A., Walker, A. R., Abbott, T. M. C., Allam, S., Bechtol, K., Benoit-Lévy, A., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Fernandez, E., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kent, S., Krause, E., Kuehn, K., Kuropatkin, N., Li, T. S., Maia, M. A. G., March, M., Marshall, J. L., Menanteau, F., Miquel, R., Ogando, R. L. C., Reil, K., Roodman, A., Rykoff, E. S., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., and Tarle, G.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500~Mpix, 3 deg^2 science field of view, and across 4 years of operation. This is done using internal comparisons of ~4x10^7 measurements of high-S/N stellar images obtained in repeat visits to fields of moderate stellar density, with the telescope dithered to move the sources around the array. An empirical astrometric model includes terms for: optical distortions; stray electric fields in the CCD detectors; chromatic terms in the instrumental and atmospheric optics; shifts in CCD relative positions of up to ~10 um when the DECam temperature cycles; and low-order distortions to each exposure from changes in atmospheric refraction and telescope alignment. Errors in this astrometric model are dominated by stochastic variations with typical amplitudes of 10-30 mas (in a 30 s exposure) and 5-10 arcmin coherence length, plausibly attributed to Kolmogorov-spectrum atmospheric turbulence. The size of these atmospheric distortions is not closely related to the seeing. Given an astrometric reference catalog at density ~0.7 arcmin^{-2}, e.g. from Gaia, the typical atmospheric distortions can be interpolated to 7 mas RMS accuracy (for 30 s exposures) with 1 arcmin coherence length for residual errors. Remaining detectable error contributors are 2-4 mas RMS from unmodelled stray electric fields in the devices, and another 2-4 mas RMS from focal plane shifts between camera thermal cycles. Thus the astrometric solution for a single DECam exposure is accurate to 3-6 mas (0.02 pixels, or 300 nm) on the focal plane, plus the stochastic atmospheric distortion., Comment: Submitted to PASP
Published: 2017
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42. An R-process enhanced star in the dwarf galaxy Tucana III

Author: Hansen, T. T., Simon, J. D., Marshall, J. L., Li, T. S., Carollo, D., DePoy, D. L., Nagasawa, D. Q., Bernstein, R. A., Drlica-Wagner, A., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., da Costa, L. N., Desai, S., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Scarpine, V., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., and Walker, A. R.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66$-$593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the $r$-process and can be classified as an $r$-I star. DES J235532 is the first $r$-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain $r$-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with $r$-I and $r$-II stars found in other dwarf galaxies and in the Milky Way halo suggests a common astrophysical origin for the neutron-capture elements seen in all $r$-process enhanced stars. We explore both internal and external scenarios for the $r$-process enrichment of Tuc III and show that with abundance patterns for additional stars it should be possible to distinguish between them., Comment: 12 pages, 5 figures. Accepted for publication in ApJ
Published: 2017
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43. KELT-18b: Puffy Planet, Hot Host, Probably Perturbed

Author: McLeod, Kim K., Rodriguez, Joseph E., Oelkers, Ryan J., Collins, Karen A., Bieryla, Allyson, Fulton, Benjamin J., Stassun, Keivan G., Gaudi, B. Scott, Penev, Kaloyan, Stevens, Daniel J., Colón, Knicole D., Pepper, Joshua, Narita, Norio, Tsuguru, Ryu, Fukui, Akihiko, Reed, Phillip A., Tirrell, Bethany, Visgaitis, Tiffany, Kielkopf, John F., Cohen, David H., Jensen, Eric L. N., Gregorio, Joao, Baştürk, Özgür, Oberst, Thomas E., Melton, Casey, Kempton, Eliza M. -R., Baldridge, Andrew, Zhao, Y. Sunny, Zambelli, Roberto, Latham, David W., Esquerdo, Gilbert A., Berlind, Perry, Calkins, Michael L., Howard, Andrew W., Isaacson, Howard, Weiss, Lauren M., Beatty, Thomas G., Eastman, Jason D., Penny, Matthew T., Siverd, Robert J., Lund, Michael B., Labadie-Bartz, Jonathan, Zhou, G., Curtis, Ivan A., Joner, Michael D., Manner, Mark, Relles, Howard, Scarpetta, Gaetano, Stephens, Denise C., Stockdale, Chris, Tan, T. G., DePoy, D. L., Marshall, Jennifer L., Pogge, Richard W., Trueblood, Mark, and Trueblood, Patricia
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87d orbit around the bright (V=10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of 6670+/-120 K and a mass of 1.524+/-0.069 Msun, situating it as one of only a handful of known transiting planets with hosts that are as hot, massive, and bright. The planet has a mass of 1.18+/-0.11 Mjup, a radius of 1.57+/-0.04 Rjup, and a density of 0.377+/-0.040 g/cm^3, making it one of the most inflated planets known around a hot star. We argue that KELT-18b's high temperature and low surface gravity, which yield an estimated ~600 km atmospheric scale height, combined with its hot, bright host make it an excellent candidate for observations aimed at atmospheric characterization. We also present evidence for a bound stellar companion at a projected separation of ~1100 AU, and speculate that it may have contributed to the strong misalignment we suspect between KELT-18's spin axis and its planet's orbital axis. The inferior conjunction time is 2457542.524998 +/-0.000416 (BJD_TDB) and the orbital period is 2.8717510 +/- 0.0000029 days. We encourage Rossiter-McLaughlin measurements in the near future to confirm the suspected spin-orbit misalignment of this system., Comment: 16 pages, 13 figures, 6 tables, accepted to AJ
Published: 2017
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44. Eight new luminous z > 6 quasars selected via SED model fitting of VISTA, WISE and Dark Energy Survey Year 1 Observations

Author: Reed, S. L., McMahon, R. G., Martini, P., Banerji, M., Auger, M., Hewett, P. C., Koposov, S. E., Gibbons, S. L. J., Gonzalez-Solares, E., Ostrovski, F., Tie, S. S., Abdalla, F. B., Allam, S., Benoit-Levy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Evrard, A. E., Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Garcıa-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gutierrez, G., James, D. J., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., Marshall, J. L., Melchior, P., Miller, C. J., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Tucker, D. L., Walker, A. R., and Wester, W.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present the discovery and spectroscopic confirmation with the ESO NTT and Gemini South telescopes of eight new 6.0 < z < 6.5 quasars with z$_{AB}$ < 21.0. These quasars were photometrically selected without any star-galaxy morphological criteria from 1533 deg$^{2}$ using SED model fitting to photometric data from the Dark Energy Survey (g, r, i, z, Y), the VISTA Hemisphere Survey (J, H, K) and the Wide-Field Infrared Survey Explorer (W1, W2). The photometric data was fitted with a grid of quasar model SEDs with redshift dependent Lyman-{\alpha} forest absorption and a range of intrinsic reddening as well as a series of low mass cool star models. Candidates were ranked using on a SED-model based $\chi^{2}$-statistic, which is extendable to other future imaging surveys (e.g. LSST, Euclid). Our spectral confirmation success rate is 100% without the need for follow-up photometric observations as used in other studies of this type. Combined with automatic removal of the main types of non-astrophysical contaminants the method allows large data sets to be processed without human intervention and without being over run by spurious false candidates. We also present a robust parametric redshift estimating technique that gives comparable accuracy to MgII and CO based redshift estimators. We find two z $\sim$ 6.2 quasars with HII near zone sizes < 3 proper Mpc which could indicate that these quasars may be young with ages < 10$^6$ - 10$^7$ years or lie in over dense regions of the IGM. The z = 6.5 quasar VDESJ0224-4711 has J$_{AB}$ = 19.75 is the second most luminous quasar known with z > 6.5., Comment: 19 pages, 15 figures
Published: 2017
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45. Weak lensing magnification in the Dark Energy Survey Science Verification Data

Author: Garcia-Fernandez, M., Sánchez, E., Sevilla-Noarbe, I., Suchyta, E., Huff, E. M., Gaztanaga, E., Aleksić, J., Ponce, R., Castander, F. J., Hoyle, B., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Crocce, M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Evrard, A. E., Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gerdes, D. W., Giannantonio, T., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Jarvis, M., Kirk, D., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., MacCrann, N., Maia, M. A. G., March, M., Marshall, J. L., Melchior, P., Miquel, R., Mohr, J. J., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Scarpine, V., Schubnell, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Tarle, G., Thomas, D., Walker, A. R., and Wester, W.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: In this paper the effect of weak lensing magnification on galaxy number counts is studied by cross-correlating the positions of two galaxy samples, separated by redshift, using data from the Dark Energy Survey Science Verification dataset. The analysis is carried out for two photometrically-selected galaxy samples, with mean photometric redshifts in the $0.2 < z < 0.4$ and $0.7 < z < 1.0$ ranges, in the riz bands. A signal is detected with a $3.5\sigma$ significance level in each of the bands tested, and is compatible with the magnification predicted by the $\Lambda$CDM model. After an extensive analysis, it cannot be attributed to any known systematic effect. The detection of the magnification signal is robust to estimated uncertainties in the outlier rate of the pho- tometric redshifts, but this will be an important issue for use of photometric redshifts in magnification mesurements from larger samples. In addition to the detection of the magnification signal, a method to select the sample with the maximum signal-to-noise is proposed and validated with data., Comment: 18 pages, 16 figures, submitted to MNRAS
Published: 2016
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46. A Search for Kilonovae in the Dark Energy Survey

Author: Doctor, Z., Kessler, R., Chen, H. Y., Farr, B., Finley, D. A., Foley, R. J., Goldstein, D. A., Holz, D. E., Kim, A. G., Morganson, E., Sako, M., Scolnic, D., Smith, M., Soares-Santos, M., Spinka, H., Abbott, T. M. C., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Levy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., DAndrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Drlica-Wagner, A., Eifler, T. F., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., Menanteau, F., Miquel, R., Neilsen, E., Nichol, R. C., Nord, B., Plazas, A. A., Romer, A. K., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Walker, A. R., and Wester, W.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The coalescence of a binary neutron star (BNS) pair is expected to produce gravitational waves (GW) and electromagnetic (EM) radiation, both of which may be detectable with currently available instruments. We describe a search for a theoretically predicted r-process optical transient from these mergers, dubbed the kilonova (KN), using griz broadband data from the Dark Energy Survey Supernova Program (DES-SN). Some models predict KNe to be redder, shorter-lived, and dimmer than supernovae (SNe), but at present the event rate of KNe is poorly constrained. We simulate observations of KN and SN light curves with the Monte-Carlo simulation code SNANA to optimize selection requirements, determine search efficiency, and predict SN backgrounds. We also perform an analysis using fake point sources on images to account for anomalous efficiency losses from difference-imaging on bright low-redshift galaxies. Our analysis of the first two seasons of DES-SN data results in 0 events, and is consistent with our prediction of 1.1 background events based on simulations of SN. Given our simulation prediction, there is a 33 percent chance of finding 0 events in the data. Assuming no underlying galaxy flux, our search sets 90 percent upper limits on the KN volumetric rate of $1.0\times10^7$ Gpc$^{-3}$ yr$^{-1}$ for the dimmest KN model we consider (peak i-band absolute magnitude $M_i=-11.4$ mag) and $2.4\times10^4$ Gpc$^{-3}$ yr$^{-1}$ for the brightest ($M_i=-16.2$ mag). Accounting for efficiency loss from host galaxy Poisson noise, these limits are 1.1 times higher; accounting for anomalous subtraction artifacts on bright galaxies, these limits are ~3 times higher. While previous KN searches were based on triggered follow-up, this analysis is the first untriggered optical KN search and informs selection requirements and strategies for future KN searches and GW follow-up observations.
Published: 2016
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47. A Study of Quasar Selection in the Dark Energy Survey Supernova fields

Author: Tie, S. S., Martini, P., Mudd, D., Ostrovski, F., Reed, S. L., Lidman, C., Kochanek, C., Davis, T. M., Sharp, R., Uddin, S., King, A., Wester, W., Tucker, B. E., Tucker, D. L., Buckley-Geer, E., Carollo, D., Childress, M., Glazebrook, K., Hinton, S. R., Lewis, G., Macaulay, E., O'Neill, C. R., Abbott, T. M. C., Abdalla, F. B., Annis, J., Benoit-L'evy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Gerdes, D. W., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Menanteau, F., Miller, C. J., Miquel, R., Nichol, R. C., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Walker, A. R., and Collaboration, The DES
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present a study of quasar selection using the DES supernova fields. We used a quasar catalog from an overlapping portion of the SDSS Stripe 82 region to quantify the completeness and efficiency of selection methods involving color, probabilistic modeling, variability, and combinations of color/probabilistic modeling with variability. We only considered objects that appear as point sources in the DES images. We examine color selection methods based on the WISE mid-IR W1-W2 color, a mixture of WISE and DES colors (g-i and i-W1) and a mixture of VHS and DES colors (g-i and i-K). For probabilistic quasar selection, we used XDQSOz, an algorithm that employs an empirical multi-wavelength flux model of quasars to assign quasar probabilities. Our variability selection uses the multi-band chi2-probability that sources are constant in the DES Year 1 griz-band light curves. The completeness and efficiency are calculated relative to an underlying sample of point sources that are detected in the required selection bands and pass our data quality and photometric error cuts. We conduct our analyses at two magnitude limits, i<19.8 mag and i<22 mag. For sources with W1 and W2 detections, the W1-W2 color or XDQSOz method combined with variability gives the highest completenesses of >85% for both i-band magnitude limits and efficiencies of >80% to the bright limit and >60% to the faint limit; however, the giW1 and giW1+variability methods give the highest quasar surface densities. The XDQSOz method and combinations of W1W2/giW1/XDQSOz with variability are among the better selection methods when both high completeness and high efficiency are desired. We also present the OzDES Quasar Catalog of 1,263 spectroscopically-confirmed quasars taken by the OzDES survey. The catalog includes quasars with redshifts up to z~4 and brighter than i=22 mag, although the catalog is not complete up this magnitude limit., Comment: 16 pages, 12 figures, 3 tables; Submitted to ApJ. The OzDES Quasar Catalog can be downloaded at http://bit.ly/2fWsK9t . For a video summary of the paper, please see https://www.youtube.com/watch?v=JeQNdUATze0
Published: 2016
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48. Farthest Neighbor: The Distant Milky Way Satellite Eridanus II

Author: Li, T. S., Simon, J. D., Drlica-Wagner, A., Bechtol, K., Wang, M. Y., García-Bellido, J., Frieman, J., Marshall, J. L., James, D. J., Strigari, L., Pace, A. B., Balbinot, E., Zhang, Y., Abbott, T. M. C., Allam, S., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Flaugher, B., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Krause, E., Kuehn, K., Lin, H., Maia, M. A. G., March, M., Menanteau, F., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., Tucker, D. L., Walker, A. R., Wechsler, R. H., Wester, W., and Yanny, B.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present Magellan/IMACS spectroscopy of the recently-discovered Milky Way satellite Eridanus II (Eri II). We identify 28 member stars in Eri II, from which we measure a systemic radial velocity of $v_{\rm hel} = 75.6 \pm 1.3~\mbox{(stat.)} \pm 2.0~\mbox{(sys.)}~\mathrm{km\,s^{-1}}$ and a velocity dispersion of $6.9^{+1.2}_{-0.9}~\mathrm{km\,s^{-1}}$. Assuming that Eri~II is a dispersion-supported system in dynamical equilibrium, we derive a mass within the half-light radius of Eri II is $1.2^{+0.4}_{-0.3} \times 10^{7}~\mathrm{M_\odot}$, indicating a mass-to-light ratio of $420^{+210}_{-140}~\mathrm{M_\odot}/\mathrm{L_\odot}$ and confirming that it is a dark matter-dominated dwarf galaxy. From the equivalent width measurements of the CaT lines of 16 red giant member stars, we derive a mean metallicity of ${\rm [Fe/H]} = -2.38 \pm 0.13$ and a metallicity dispersion of $\sigma_{\rm [Fe/H]} = 0.47 ^{+0.12}_{-0.09}$. The velocity of Eri II in the Galactic Standard of Rest frame is $v_{\rm GSR} = -66.6~\mathrm{km\,s^{-1}}$, indicating that either Eri II is falling into the Milky Way potential for the first time or it has passed the apocenter of its orbit on a subsequent passage. At a Galactocentric distance of $\sim$370 kpc, Eri II is one of the Milky Way's most distant satellites known. Additionally, we show that the bright blue stars previously suggested to be a young stellar population are not associated with Eri II. The lack of gas and recent star formation in Eri II is surprising given its mass and distance from the Milky Way, and may place constraints on models of quenching in dwarf galaxies and on the distribution of hot gas in the Milky Way halo. Furthermore, the large velocity dispersion of Eri II can be combined with the existence of a central star cluster to constrain MACHO dark matter with mass $\gtrsim10~\mathrm{M_\odot}$., Comment: 16 pages, 10 figures, Accepted for publication in ApJ
Published: 2016
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49. Nearest Neighbor: The Low-Mass Milky Way Satellite Tucana III

Author: Simon, J. D., Li, T. S., Drlica-Wagner, A., Bechtol, K., Marshall, J. L., James, D. J., Wang, M. Y., Strigari, L., Balbinot, E., Kuehn, K., Walker, A. R., Abbott, T. M. C., Allam, S., Annis, J., Benoit-Levy, A., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Fernandez, E., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gutierrez, G., Kuropatkin, N., Maia, M. A. G., Martini, P., Menanteau, F., Miller, C. J., Miquel, R., Neilsen, E., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Rykoff, E. S., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Whiteway, L., and Yanny, B.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite Tucana III (Tuc III). We identify 26 member stars in Tuc III, from which we measure a mean radial velocity of v_hel = -102.3 +/- 0.4 (stat.) +/- 2.0 (sys.) km/s, a velocity dispersion of 0.1^+0.7_-0.1 km/s, and a mean metallicity of [Fe/H] = -2.42^+0.07_-0.08. The upper limit on the velocity dispersion is sigma < 1.5 km/s at 95.5% confidence, and the corresponding upper limit on the mass within the half-light radius of Tuc III is 9.0 x 10^4 Msun. We cannot rule out mass-to-light ratios as large as 240 Msun/Lsun for Tuc III, but much lower mass-to-light ratios that would leave the system baryon-dominated are also allowed. We measure an upper limit on the metallicity spread of the stars in Tuc III of 0.19 dex at 95.5% confidence. Tuc III has a smaller metallicity dispersion and likely a smaller velocity dispersion than any known dwarf galaxy, but a larger size and lower surface brightness than any known globular cluster. Its metallicity is also much lower than those of the clusters with similar luminosity. We therefore tentatively suggest that Tuc III is the tidally-stripped remnant of a dark matter-dominated dwarf galaxy, but additional precise velocity and metallicity measurements will be necessary for a definitive classification. If Tuc III is indeed a dwarf galaxy, it is one of the closest external galaxies to the Sun. Because of its proximity, the most luminous stars in Tuc III are quite bright, including one star at V=15.7 that is the brightest known member star of an ultra-faint satellite., Comment: 14 pages, 4 figures (2 in color), 3 tables. Submitted for publication in the AAS Journals
Published: 2016
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50. Imprint of DES super-structures on the Cosmic Microwave Background

Author: Kovács, A., Sánchez, C., García-Bellido, J., Nadathur, S., Crittenden, R., Gruen, D., Huterer, D., Bacon, D., DeRose, J., Dodelson, S., Gaztañaga, E., Kirk, D., Lahav, O., Miquel, R., Naidoo, K., Peacock, J. A., Soergel, B., Whiteway, L., Abdalla, F. B., Allam, S., Annis, J., Benoit-Lévy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Eifler, T. F., Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Giannantonio, T., Goldstein, D. A., Gruendl, R. A., Gutierrez, G., James, D. J., Kuehn, K., Kuropatkin, N., Marshall, J. L., Melchior, P., Menanteau, F., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Sanchez, E., Scarpine, V., Sevilla-Noarbe, I., Sobreira, F., Suchyta, E., Swanson, M., Tarle, G., Thomas, D., and Walker, A. R.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Small temperature anisotropies in the Cosmic Microwave Background can be sourced by density perturbations via the late-time integrated Sachs-Wolfe effect. Large voids and superclusters are excellent environments to make a localized measurement of this tiny imprint. In some cases excess signals have been reported. We probed these claims with an independent data set, using the first year data of the Dark Energy Survey in a different footprint, and using a different super-structure finding strategy. We identified 52 large voids and 102 superclusters at redshifts $0.2 < z < 0.65$. We used the Jubilee simulation to a priori evaluate the optimal ISW measurement configuration for our compensated top-hat filtering technique, and then performed a stacking measurement of the CMB temperature field based on the DES data. For optimal configurations, we detected a cumulative cold imprint of voids with $\Delta T_{f} \approx -5.0\pm3.7~\mu K$ and a hot imprint of superclusters $\Delta T_{f} \approx 5.1\pm3.2~\mu K$ ; this is $\sim1.2\sigma$ higher than the expected $|\Delta T_{f}| \approx 0.6~\mu K$ imprint of such super-structures in $\Lambda$CDM. If we instead use an a posteriori selected filter size ($R/R_{v}=0.6$), we can find a temperature decrement as large as $\Delta T_{f} \approx -9.8\pm4.7~\mu K$ for voids, which is $\sim2\sigma$ above $\Lambda$CDM expectations and is comparable to previous measurements made using SDSS super-structure data., Comment: 16 pages, 12 figures. Accepted for publication by MNRAS without further review. Author list updated
Published: 2016
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