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1. KELT-22Ab: A Massive Hot Jupiter Transiting a Near Solar Twin

Author

Labadie-Bartz, Jonathan, Rodriguez, Joseph E., Stassun, Keivan G., Ciardi, David R., Johnson, Marshall C., Gaudi, B. Scott, Penev, Kaloyan M., Bieryla, Allyson, Latham, David W., Pepper, Joshua, Collins, Karen A., Evans, Phil, Relles, Howard M., Siverd, Robert J., Bento, Joao, Yao, Xinyu, Stockdale, Chris, Tan, Thiam-Guan, Zhou, George, Colon, Knicole D., Eastman, Jason D., Albrow, Michael D., Malpas, Amber, Bayliss, Daniel, Beatty, Thomas G., Bozza, Valerio, Cohen, David H., Curtis, Ivan A., DePoy, Darren L., Feliz, Dax, Fulton, Benjamin J., Gregorio, Joao, James, David, Jang-Condell, Hannah, Jensen, Eric L., Johnson, John A., Johnson, Samson A., Joner, Michael D., Kielkopf, John, Kuhn, Rudolf B., Lund, Michael B., Manner, Mark, Marshall, Jennifer L., McCrady, Nate, McLeod, Kim K., Oberst, Thomas E., Penny, Matthew T., Pogge, Rick, Reed, Phillip A., Sliski, David H., Stephens, Denise C., Stevens, Daniel J., Trueblood, Mark, Trueblood, Patricia, Villanueva Jr., Steven, Wittenmyer, Robert A., Wright, Jason T., Zambelli, Roberto, Berlind, Perry, Calkins, Michael L., and Esquerdo, Gilbert A.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright ($V\sim 11.1$) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of $P = 1.3866529 \pm 0.0000027 $ days, a radius of $R_{P} = 1.285_{-0.071}^{+0.12}~R_{J}$, and a relatively large mass of $M_{P} = 3.47_{-0.14}^{+0.15}~ M_{J}$. The star has $R_{\star} = 1.099_{-0.046}^{+0.079}~ R_{\odot}$, $M_{\star} = 1.092_{-0.041}^{+0.045}~ M_{\odot}$, ${T_{\rm eff}\,} = 5767_{-49}^{+50}~$ K, ${\log{g_\star}} = 4.393_{-0.060}^{+0.039}~$ (cgs), and [m/H] = $+0.259_{-0.083}^{+0.085}~$, and thus, other than its slightly super-solar metallicity, appears to be a near solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin disk stars. Nevertheless, the star is rotating quite rapidly for its estimated age, shows evidence of chromospheric activity, and is somewhat metal rich. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6\arcsec ($\sim$1400 AU). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semi-major axis of $a/R_{\star} = 4.97$), and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semi-major axis of KELT-22Ab is decreasing rapidly, and is thus predicted to spiral into the star within the next Gyr., Comment: 14 pages, 13 figures, 5 tables

Published
2018
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2. A study of quasar selection in the supernova fields of the Dark Energy Survey

Author

Tie, Suk Sien, Martini, Paul, Mudd, Dale, Ostrovski, F., Reed, Sophie L., Lidman, Chris, Kochanek, C.S., Davis, Tamara M., Sharp, Robert G., Uddin, Syed, King, Anthea L., Wester, William Carl, Tucker, Bradley, Tucker, Douglas L., Buckley-Geer, Elizabeth, Carollo, Daniela, Childress, Michael, Glazebrook, Karl, Hinton, Samuel, Lewis, Geraint F., Macaulay, Edward, O'Neill, C. R., Abbott, Timothy M. C., Abdalla, Filipe B., Annis, James T., Benoit-Lévy, Aurélien, Bertin, Emmanuel, Brooks, D., Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, Costa, Luiz N. da, DePoy, Darren L., Desai, S., Doel, Peter, Eifler, Tim, Evrard, August E., Finley, David A., Flaugher, Brenna, Fosalba Vela, Pablo, Frieman, Joshua A., García-Bellido, Juan, Gaztañaga, Enrique, Gerdes, David W., Goldstein, Daniel Abraham, Gruen, Daniel, Gruendl, Robert A., Gutierrez, Gaston R., Honscheid, K., James, David J., Kuehn, Kyler, Kuropatkin, Nikolay P., Lima, Marcos Vinicius Borges Teixeira, Maia, Marcio Antonio Geimba, Marshall, Jennifer L., Menanteau, Felipe, Miller, Christopher J., Miquel, Ramon, Nichol, Robert C., Nord, Brian Dennis, Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Romer, Anita K., Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Scarpine, Victor Emanuel, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thomas, D., Walker, Alistair, and DES Collaboration

Subjects
Mapeamentos astronômicos, Fotometria astronômica, Catalogos astronomicos, general [Quasars], Quasars
Abstract

We present a study of quasar selection using the supernova fields of the Dark Energy Survey (DES). 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. In all cases, we considered only objects that appear as point sources in the DES images. We examine color selection methods based on the Wide-field Infrared Survey Explorer (WISE) mid- IR W1 - W2 color, a mixture of WISE and DES colors (g − i and i - W1), and a mixture of Vista Hemisphere Survey and DES colors (g − i and i − K ). For probabilistic quasar selection, we used XDQSO, an algorithm that employs an empirical multi-wavelength flux model of quasars to assign quasar probabilities. Our variability selection uses the multi-band χ2-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, i85% 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 1263 spectroscopically confirmed quasars from three years of OzDES observation in the 30 deg2 of the DES supernova fields. The catalog includes quasars with redshifts up to z4 and brighter than i = 22 mag, although the catalog is not complete up to this magnitude limit.

Published
2017

3. An r -process enhanced star in the dwarf galaxy Tucana III

Author

Hansen, Terese T., Simon, Josh D., Marshall, Jennifer L., Li, T. S., Carollo, Daniela, DePoy, Darren L., Nagasawa, Daniel Q., Bernstein, Rebecca A., Drlica-Wagner, Alex, Abdalla, Filipe B., Allam, Sahar S., Annis, James T., Bechtol, Keith, Benoit-Lévy, Aurélien, Brooks, D., Buckley-Geer, Elizabeth, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, Costa, Luiz N. da, Desai, S., Eifler, Tim, Fausti Neto, Angelo, Flaugher, Brenna, Frieman, Joshua A., García-Bellido, Juan, Gaztañaga, Enrique, Gerdes, David W., Gruen, Daniel, Gruendl, Robert A., Gschwend, Julia de Figueiredo, Gutierrez, Gaston R., James, David J., Krause, Elisabeth, Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Miquel, Ramon, Plazas Malagón, Andrés Alejandro, Romer, Anita K., Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Scarpine, Victor Emanuel, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Walker, Alistair, and DES Collaboration

Subjects
dwarf [Galaxies], Readable tables, Nucleosíntese, Captura radioativa de nêutrons, abundances [Stars], abundances [galaxies], Metalicidade, Composicao estelar, machine [Supporting material], chemically peculiar [Stars]
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 (MW) 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 rprocess 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 MW 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.

Published
2017

4. Farthest neighbor : the distant Milky Way satellite Eridanus II

Author

Li, T. S., Simon, Josh D., Drlica-Wagner, Alex, Bechtol, Keith, Wang, M., García-Bellido, Juan, Frieman, Joshua A., Marshall, Jennifer L., James, David J., Strigari, Louis E., Pace, Andrew B., Balbinot, Eduardo, Zhang, Yuanyuan, Abbott, Timothy M. C., Allam, Sahar S., Benoit-Lévy, Aurélien, Bernstein, Gary M., Bertin, Emmanuel, Brooks, D., Burke, David Lyle, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Eifler, Tim, Flaugher, Brenna, Goldstein, Daniel Abraham, Gruen, Daniel, Gruendl, Robert A., Gschwend, Julia de Figueiredo, Gutierrez, Gaston R., Krause, Elisabeth, Kuehn, Kyler, Lin, H., Maia, Marcio Antonio Geimba, March, Marisa Cristina, Menanteau, Felipe, Miquel, Ramon, Plazas Malagón, Andrés Alejandro, Romer, Anita K., Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Sobreira, Flávia, Suchyta, Eric, Tarle, Gregory, Thomas, D., Tucker, Douglas L., Walker, Alistair, Wechsler, Risa H., Wester, William Carl, Yanny, Brian, and DES Collaboration

Subjects
dwarf [Galaxies], Populacoes estelares, Via láctea, abundances [Stars], Dark matter, Local group, Matéria escura, stellar content [Galaxies], individual (Eridanus II) [Galaxies], Composicao estelar, Metalicidade, Galáxias
Abstract

We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite EridanusII (Eri II). We identify 28 member stars in EriII, from which we measure a systemic radial velocity of vhel = 75.6 1.3 (stat.) 2.0 (sys.) km s-1 and a velocity dispersion of - 6.9+0.9 1.2 km s-1. Assuming that EriII is a dispersion-supported system in dynamical equilibrium, we derive a mass within the half-light radius of - ´ 1.2+ 10 0.3 0.4 7 M, indicating a mass-tolight ratio of - 420+140 210 M/L and confirming that it is a dark matter-dominated dwarf galaxy. From the equivalent width measurements of the Ca triplet lines of 16 red giant member stars, we derive a mean metallicity of [Fe/ H]=−2.38±0.13 and a metallicity dispersion of s[ / ] = - 0.47+ Fe H 0.09 0.12. The velocity of EriII in the Galactic standard of rest frame is vGSR=−66.6 km s-1, indicating that either EriII is falling into the Milky Way potential for the first time or that it has passed the apocenter of its orbit on a subsequent passage. At a Galactocentric distance of 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 EriII. The lack of gas and recent star formation in EriII 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 massive compact halo object dark matter with mass 10 M.

Published
2017

5. Nearest neighbor : the low-mass Milky Way satellite Tucana III

Author

Simon, Josh D., Li, T. S., Drlica-Wagner, Alex, Bechtol, Keith, Marshall, Jennifer L., James, David J., Wang, M., Strigari, Louis E., Balbinot, Eduardo, Kuehn, Kyler, Walker, Alistair, Abbott, Timothy M. C., Allam, Sahar S., Annis, James T., Benoit-Lévy, Aurélien, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Doel, Peter, Fernandez, Enrique, Flaugher, Brenna, Frieman, Joshua A., García-Bellido, Juan, Gaztañaga, Enrique, Goldstein, Daniel Abraham, Gruen, Daniel, Gutierrez, Gaston R., Kuropatkin, Nikolay P., Maia, Marcio Antonio Geimba, Martini, Paul, Menanteau, Felipe, Miller, Christopher J., Miquel, Ramon, Neilsen, Eric H., Nord, Brian Dennis, Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Romer, Anita K., Rykoff, Eli, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Scarpine, Victor Emanuel, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Whiteway, L., Yanny, Brian, and DES Collaboration

Subjects
dwarf [Galaxies], Via láctea, individual (Tucana III) [Galaxies], abundances [Stars], Dark matter, Local group, Matéria escura, stellar content [Galaxies], Composicao estelar, Metalicidade, Galáxias
Abstract

We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite TucanaIII (Tuc III). We identify 26 member stars in TucIII from which we measure a mean radial velocity of vhel=−102.3±0.4 (stat.)±2.0(sys.) km s-1, a velocity dispersion of - 0.1+0.1 0.7 km s-1, and a mean metallicity of = - - [Fe/H] 2.42+0.08 0.07. The upper limit on the velocity dispersion is σ

Published
2017

6. Observation of two new L4 Neptune Trojans in the Dark Energy Survey supernova fields

Author

Gerdes, David W., Jennings, R. J., Bernstein, Gary M., Sako, Masao, Adams, Fred, Goldstein, Daniel Abraham, Kessler, Richard S., Hamilton, S., Abbott, Timothy M. C., Abdalla, Filipe B., Allam, Sahar S., Benoit-Lévy, Aurélien, Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Capozzi, Diego, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Dietrich, Jörg P., Doel, Peter, Eifler, Tim, Fausti Neto, Angelo, Flaugher, Brenna, Frieman, Joshua A., Gaztañaga, Enrique, Gruen, Daniel, Gruendl, Robert A., Gutierrez, Gaston R., Honscheid, K., James, David J., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Li, T. S., Maia, Marcio Antonio Geimba, March, Marisa Cristina, Martini, Paul, Miller, Christopher J., Miquel, Ramon, Nichol, Robert C., Nord, Brian Dennis, Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Romer, Anita K., Roodman, Aaron, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thaler, Jon J., Walker, Alistair, Wester, William Carl, Zhang, Yuanyuan, and DES Collaboration

Subjects
Asteroides, Sistema solar, Fotometria astronômica, Minor planets, general [Asteroids]
Abstract

We report the discovery of the eighth and ninth known Trojans in stable orbits around Neptune’s leading Lagrange point, L4. The objects 2014QO441 and 2014QP441 were detected in data obtained during the 2013–14 and 2014–15 observing seasons by the Dark Energy Survey, using the Dark Energy Camera (DECam) on the 4-m Blanco telescope at Cerro Tololo Inter-American Observatory. Both are in high-inclination orbits (18°.8 and 19°.4, respectively). With an eccentricity of 0.104, 2014QO441 has the most eccentric orbit of the 11 known stable Neptune Trojans. Here we describe the search procedure and investigate the objects’ long-term dynamical stability and physical properties.

Published
2016

7. Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

Author

Bonnett, Christopher, Troxel, Michael, Hartley, William, Amara, Adam, Leistedt, Boris, Becker, Matthew R., Bernstein, Gary M., Bridle, Sarah Louise, Bruderer, Claudio, Busha, M. T., Carrasco Kind, Matías, Childress, Michael, Castander Serentill, Francisco Javier, Chang, Chihway, Crocce, Martin, Davis, Tamara M., Eifler, Tim, Frieman, Joshua A., Gangkofner, C., Gaztañaga, Enrique, Glazebrook, Karl, Gruen, Daniel, Kacprzak, Tomasz, King, Anthea L., Kwan, Juliana, Lahav, Ofer, Lewis, Geraint F., Lidman, Chris, Lin, H., MacCrann, Niall, Miquel, Ramon, O'Neill, C. R., Palmese, A., Peiris, Hiranya V., Refregier, Alexandre, Rozo, Eduardo, Rykoff, Eli, Sadeh, Iftach, Sánchez Alonso, Carles, Sheldon, Erin, Uddin, Syed, Wechsler, Risa H., Zuntz, J., Abbott, Timothy M. C., Abdalla, Filipe B., Allam, Sahar S., Armstrong, Robert, Banerji, M., Bauer, Anne Hollister, Benoit-Lévy, Aurélien, Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Capozzi, Diego, Carnero Rosell, Aurelio, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Dietrich, Jörg P., Doel, Peter, Fausti Neto, Angelo, Fernandez, Enrique, Flaugher, Brenna, Fosalba Vela, Pablo, Gerdes, David W., Gruendl, Robert A., Honscheid, K., Jain, Bhuvnesh, James, David J., Jarvis, Michael, Kim, A. G., Kuehn, Kyler, Kuropatkin, Nikolay P., Li, T. S., Lima, Marcos Vinicius Borges Teixeira, Maia, Marcio Antonio Geimba, March, Marisa Cristina, Marshall, Jennifer L., Martini, Paul, Melchior, Peter M., Miller, Christopher J., Neilsen, Eric H., Nichol, Robert C., Nord, Brian Dennis, Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Reil, Kevin, Romer, Anita K., Roodman, Aaron, Sako, Masao, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thaler, Jon J., Thomas, D., Vikram, Vinu, Walker, Alistair, and DES Collaboration

Subjects
Lentes gravitacionais, DATA RELEASE, SURVEY REQUIREMENTS, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, SHAPE MEASUREMENT, 01 natural sciences, Cosmology, Physics, Particles & Fields, PRECISION COSMOLOGY, LARGE-SCALE STRUCTURE, 0103 physical sciences, STAR-FORMING GALAXIES, PHOTO-Z PERFORMANCE, Deslocamento para o vermelho, Galáxias, PHOTOMETRIC REDSHIFTS, 010303 astronomy & astrophysics, Weak gravitational lensing, Astrophysics::Galaxy Astrophysics, QB, Photometric redshift, Physics, Science & Technology, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Sigma, VLT DEEP SURVEY, Redshift survey, Galaxy, Redshift, Fotometria astronômica, Physical Sciences, astro-ph.CO, Dark energy, NEURAL-NETWORKS
Abstract

We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model-or machine learning-based photometric redshift methods-ANNZ2, BPZ calibrated against BCC-Ufig simulations, SKYNET, and TPZ-are analyzed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-z's. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 +/- 0.01 over the range 0.3 < z < 1.3, we construct three tomographic bins with means of z = {0.45;0.67;1.00}. These bins each have systematic uncertainties delta z

Published
2016

8. The Phoenix stream : a cold stream in the southern hemisphere

Author

Balbinot, Eduardo, Yanny, Brian, Li, T. S., Santiago, Basilio Xavier, Marshall, Jennifer L., Finley, David A., Pieres, Adriano, Abbott, Timothy M. C., Abdalla, Filipe B., Allam, Sahar S., Benoit-Lévy, Aurélien, Bernstein, Gary M., Bertin, Emmanuel, Brooks, D., Burke, David Lyle, Carnero Rosell, Aurelio, Carrasco Kind, Matías, Carretero Palacios, Jorge, Cunha, Carlos Eduardo, Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Doel, Peter, Estrada, Juan, Flaugher, Brenna, Frieman, Joshua A., Gerdes, David W., Gruen, Daniel, Gruendl, Robert A., Honscheid, K., James, David J., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, March, Marisa Cristina, Martini, Paul, Miquel, Ramon, Nichol, Robert C., Ogando, Ricardo L.C., Romer, Anita K., Sanchez-Alvaro, Eusebio, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Tarle, Gregory, Thomas, D., Tucker, Douglas L., Walker, Alistair, and DES Collaboration

Subjects
Fotometria astronômica, Evolucao estelar, halo [Galaxy], Galaxia, structure [Galaxy]
Abstract

We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color–magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color–magnitude space, we find that a stellar population with age τ=11.5±0.5 Gyr and [Fe/H]

Published
2016

9. redMaGiC : selecting luminous red galaxies from the DES Science Verification data

Author

Rozo, Eduardo, Rykoff, Eli, Abate, Alexandra, Bonnet, Christopher Clive, Crocce, Martin, Davis, Christopher P., Hoyle, Ben, Leistedt, Boris, Peiris, Hiranya V., Wechsler, Risa H., Abbott, Timothy M. C., Abdalla, Filipe B., Banerji, M., Bauer, Anne Hollister, Benoit-Lévy, Aurélien, Bernstein, Gary M., Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Capozzi, Diego, Carnero Rosell, Aurelio, Carollo, Daniela, Carrasco Kind, Matías, Carretero Palacios, Jorge, Castander Serentill, Francisco Javier, Childress, Michael, Cunha, Carlos Eduardo, D'Andrea, Christopher B., Davis, Tamara M., DePoy, Darren L., Desai, S., Diehl, H. Thomas, Dietrich, Jörg P., Doel, Peter, Eifler, Tim, Evrard, August E., Fausti Neto, Angelo, Flaugher, Brenna, Fosalba Vela, Pablo, Frieman, Joshua A., Gaztañaga, Enrique, Gerdes, David W., Glazebrook, Karl, Gruen, Daniel, Gruendl, Robert A., Honscheid, K., James, David J., Jarvis, Michael, Kim, A. G., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Lewis, Geraint F., Lidman, Chris, Lima, Marcos Vinicius Borges Teixeira, Maia, Marcio Antonio Geimba, March, Marisa Cristina, Martini, Paul, Melchior, Peter M., Miller, Christopher J., Miquel, Ramon, Mohr, Joseph J., Nichol, Robert C., Nord, Brian Dennis, O'Neill, C. R., Ogando, Ricardo L.C., Plazas Malagón, Andrés Alejandro, Romer, Anita K., Roodman, Aaron, Sako, Masao, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Thaler, Jon J., Thomas, D., Uddin, Syed, Vikram, Vinu, Walker, Alistair, Wester, William Carl, Zhang, Yuanyuan, and Costa, Luiz N. da

Subjects
statistical [Methods], Fotometria astronômica, photometric [Techniques], general [Galaxies], Deslocamento para o vermelho, Galáxias
Abstract

We introduce redMaGiC, an automated algorithm for selecting luminous red galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the colour cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine learning-based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalogue sampling the redshift range z ∈ [0.2, 0.8]. Our fiducial sample has a comoving space density of 10−3 (h−1 Mpc)−3, and a median photo-z bias (zspec − zphoto) and scatter (σz/(1 + z)) of 0.005 and 0.017, respectively. The corresponding 5σ outlier fraction is 1.4 per cent.We also test our algorithm with Sloan Digital Sky Survey Data Release 8 and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1 per cent level.

Published
2016

10. Stellar kinematics and metallicities in the ultra-faint dwarf galaxy Reticulum II

Author

Simon, Josh D., Drlica-Wagner, Alex, Li, T. S., Nord, Brian Dennis, Geha, Marla, Bechtol, Keith, Balbinot, Eduardo, Buckley-Geer, Elizabeth, Lin, H., Marshall, Jennifer L., Santiago, Basilio Xavier, Strigari, Louis E., Wang, M., Wechsler, Risa H., Yanny, Brian, Abbott, Timothy M. C., Bauer, Anne Hollister, Bernstein, Gary M., Bertin, Emmanuel, Brooks, D., Burke, David Lyle, Capozzi, Diego, Carnero Rosell, Aurelio, Carrasco Kind, Matías, D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Dodelson, Scott, Cunha, Carlos Eduardo, Estrada, Juan, Evrard, August E., Fausti Neto, Angelo, Fernandez, Enrique, Finley, David A., Flaugher, Brenna, Frieman, Joshua A., Gaztañaga, Enrique, Gerdes, David W., Gruen, Daniel, Gruendl, Robert A., Honscheid, K., James, David J., Kent, Stephen M., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Maia, Marcio Antonio Geimba, March, Marisa Cristina, Martini, Paul, Miller, Christopher J., Miquel, Ramon, Ogando, Ricardo L.C., Romer, Anita K., Roodman, Aaron, Sako, Masao, Sanchez-Alvaro, Eusebio, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thaler, Jon J., Tucker, Douglas L., Vikram, Vinu, Walker, Alistair, Wester, William Carl, and DES Collaboration

Subjects
dwarf [Galaxies], abundances [Stars], Dark matter, individual (Reticulum II) [Galaxies], Local group, Matéria escura, stellar content [Galaxies], Galaxia, Composicao estelar, Dinamica estelar, Grande Nuvem de Magalhães, Espectros estelares, Pequena Nuvem de Magalhães
Abstract

We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8  0.5 km s-1 and a velocity dispersion of 3.3  0.7 km s-1. The mass-to-light ratio of Ret II within its half-light radius is 470  210 M L, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km s-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H] = -2.65  0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log10 (J) 18.8 0.6 GeV cm =  2 -5 within 0 ◦. 2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.

Published
2015

11. Search for gamma-ray emission from DES dwarf spheroidal galaxy candidates with Fermi-LAT data

Author

Drlica-Wagner, Alex, Albert, Andrea, Bechtol, Keith, Wood, Matthew Dunseth, Strigari, Louis E., Sánchez-Conde, Miguel A., Baldini, Luca, Essig, Rouven, Cohen-Tanugi, Johann, Anderson, Brandon, Bellazzini, Ronaldo, Bloom, Elliott D., Caputo, Regina, Cecchi, Claudia, Charles, Eric Andre, Chiang, James, De Angelis, Alessandro, Funk, Stefan, Fusco, Piergiorgio, Gargano, Fabio, Giglietto, Nico, Giordano, Francesco, Guiriec, Sylvain, Gustafsson, Michael, Kuss, Michael, Loparco, Francesco, Lubrano, Pasquale, Mirabal, N., Mizuno, Tsunefumi, Morselli, Aldo, Ohsugi, Takashi, Orlando, Elena, Persic, Massimo, Raino, Silvia, Spada, Francesca Romana, Suson, Daniel J., Zaharijas, Gabrijela, Zimmer, Stephan, Abbott, Timothy M. C., Allam, Sahar S., Balbinot, Eduardo, Bauer, Anne Hollister, Benoit-Lévy, Aurélien, Bernstein, Rebecca A., Bernstein, Gary M., Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Burke, David Lyle, Carnero Rosell, Aurelio, Castander Serentill, Francisco Javier, Covarrubias, Ricardo A., D'Andrea, Christopher B., Costa, Luiz N. da, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Cunha, Carlos Eduardo, Eifler, Tim, Estrada, Juan, Evrard, August E., Fausti Neto, Angelo, Fernandez, Enrique, Finley, David A., Flaugher, Brenna, Frieman, Joshua A., Gaztañaga, Enrique, Gerdes, David W., Gruen, Daniel, Gruendl, Robert A., Gutierrez, Gaston R., Honscheid, K., Jain, Bhuvnesh, James, David J., Jeltema, Tesla E., Kent, Stephen M., Kron, Richard G., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, Li, T. S., Luque Canaza, Elmer Fidel, Maia, Marcio Antonio Geimba, Makler, Martín, March, Marisa Cristina, Marshall, Jennifer L., Martini, Paul, Merritt, K. Wyatt, Miller, Christopher J., Miquel, Ramon, Mohr, Joseph J., Neilsen, Eric H., Nord, Brian Dennis, Ogando, Ricardo L.C., Peoples, John, Petravick, Donald L., Pieres, Adriano, Plazas Malagón, Andrés Alejandro, Queiroz, Anna Bárbara de Andrade, Romer, Anita K., Roodman, Aaron, Rykoff, Eli, Sako, Masao, Sanchez-Alvaro, Eusebio, Santiago, Basilio Xavier, Scarpine, Victor Emanuel, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Sobreira, Flávia, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Thaler, Jon J., Thomas, D., Tucker, Douglas L., Walker, Alistair, Wechsler, Risa H., Wester, William Carl, Williams, P., Yanny, Brian, Zuntz, J., Fermi LAT Collaboration, and DES Collaboration

Subjects
dwarf [Galaxies], galaxies [Gamma rays], Leptons pesados, Dark matter, Quarks, Local group, Matéria escura, Galaxia
Abstract

Due to their proximity, high dark-matter (DM) content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of DM. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with DM halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged DM annihilation cross section for these new targets. If the estimated DM content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for DM particles with masses 20 GeV annihilating via the bb¯ or τ+τ− channels.

Published
2015

12. The LMC geometry and outer stellar populations from early DES data

Author

Balbinot, Eduardo, Santiago, Basilio Xavier, Girardi, Leo Alberto, Pieres, Adriano, Costa, Luiz N. da, Maia, Marcio Antonio Geimba, Gruendl, Robert A., Walker, Alistair, Yanny, Brian, Drlica-Wagner, Alex, Benoit-Lévy, Aurélien, Abbott, Timothy M. C., Allam, Sahar S., Annis, James T., Bernstein, Joseph P., Bernstein, Rebecca A., Bertin, Emmanuel, Brooks, D., Buckley-Geer, Elizabeth, Carnero Rosell, Aurelio, Cunha, Carlos Eduardo, DePoy, Darren L., Desai, S., Diehl, H. Thomas, Doel, Peter, Estrada, Juan, Evrard, August E., Fausti Neto, Angelo, Finley, David A., Flaugher, Brenna, Frieman, Joshua A., Gruen, Daniel, Honscheid, K., James, David J., Kuehn, Kyler, Kuropatkin, Nikolay P., Lahav, Ofer, March, Marisa Cristina, Marshall, Jennifer L., Miller, Christopher J., Miquel, Ramon, Ogando, Ricardo L.C., Peoples, John, Plazas Malagón, Andrés Alejandro, Scarpine, Victor Emanuel, Schubnell, Michael, Sevilla Noarbe, Ignacio, Smith, Robert Christopher, Soares-Santos, Marcelle, Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Tucker, Douglas L., Wechsler, Risa H., and Zuntz, J.

Subjects
Mapeamentos astronômicos, statistics [Stars], stellar content [Galaxies], Magellanic clouds, Grande Nuvem de Magalhães
Abstract

The Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey (DES). The SV footprint covers a large portion of the outer LargeMagellanic Cloud (LMC), providing photometry 1.5 mag fainter than the main sequence turn-off of the oldest LMC stellar population.We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = −38. ◦ 14 ± 0. ◦ 08 (near side in the north) and a position angle for the line of nodes of θ0 = 129. ◦ 51 ± 0. ◦ 17. We find that stars younger than ∼4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R>4 Gyr = 1.41 ± 0.01 kpc, while the younger population has R

Published
2015

13. KELT-7b: A hot Jupiter transiting a bright V=8.54 rapidly rotating F-star

Author

Bieryla, Allyson, Collins, Karen, Beatty, Thomas G., Eastman, Jason, Siverd, Robert J., Pepper, Joshua, Gaudi, B. Scott, Stassun, Keivan G., Canas, Caleb, Latham, David W., Buchhave, Lars A., Sanchis-Ojeda, Roberto, Winn, Joshua N., Jensen, Eric L. N., Kielkopf, John F., McLeod, Kim K., Gregorio, Joao, Colon, Knicole D., Street, Rachel, Ross, Rachel, Penny, Matthew, Mellon, Samuel N., Oberst, Thomas E., Fulton, Benjamin J., Wang, Ji, Berlind, Perry, Calkins, Michael L., Esquerdo, Gilbert A., DePoy, Darren L., Gould, Andrew, Marshall, Jennifer, Pogge, Richard, Trueblood, Mark, and Trueblood, Patricia

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of $1.28 \pm 0.18$ MJ, radius of $1.53_{-0.047}^{+0.046}$ RJ, and an orbital period of $2.7347749 \pm 0.0000039$ days. The bright host star (HD33643; KELT-7) is an F-star with $V=8.54$, Teff $=6789_{-49}^{+50}$ K, [Fe/H] $=0.139_{-0.081}^{+0.075}$, and $\log{g}=4.149 \pm 0.019$. It has a mass of $1.535_{-0.054}^{+0.066}$ Msun, a radius of $1.732_{-0.045}^{+0.043}$ Rsun, and is the fifth most massive, fifth hottest, and the ninth brightest star known to host a transiting planet. It is also the brightest star around which KELT has discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed characterization given its relatively low surface gravity, high equilibrium temperature, and bright host star. The rapid rotation of the star ($73 \pm 0.5$ km/s) results in a Rossiter-McLaughlin effect with an unusually large amplitude of several hundred m/s. We find that the orbit normal of the planet is likely to be well-aligned with the stellar spin axis, with a projected spin-orbit alignment of $\lambda=9.7 \pm 5.2$ degrees. This is currently the second most rapidly rotating star to have a reflex signal (and thus mass determination) due to a planetary companion measured., Comment: Accepted to The Astronomical Journal

Published
2015
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14. First-Year Spectroscopy for the SDSS-II Supernova Survey

Author

Zheng, Chen, Romani, Roger W., Sako, Masao, Marriner, John, Bassett, Bruce, Becker, Andrew, Choi, Changsu, Cinabro, David, DeJongh, Fritz, Depoy, Darren L., Dilday, Ben, Doi, Mamoru, Frieman, Joshua A., Garnavich, Peter M., Hogan, Craig J., Holtzman, Jon, Im, Myungshin, Jha, Saurabh, Kessler, Richard, Konishi, Kohki, Lampeitl, Hubert, Marshall, Jennifer L., McGinnis, David, Miknaitis, Gajus, Nichol, Robert C., Prieto, Jose Luis, Riess, Adam G., Richmond, Michael W., Schneider, Donald P., Smith, Mathew, Takanashi, Naohiro, Tokita, Kouichi, van der Heyden, Kurt, Yasuda, Naoki, Assef, Roberto J., Barentine, John, Bender, Ralf, Blandford, Roger D., Bremer, Malcolm, Brewington, Howard, Collins, Chris A., Crotts, Arlin, Dembicky, Jack, Eastman, Jason, Edge, Alastair, Elson, Ed, Eyler, Michael E., Filippenko, Alexei V., Foley, Ryan J., Frank, Stephan, Goobar, Ariel, Harvanek, Michael, Hopp, Ulrich, Ihara, Yutaka, Kahn, Steven, Ketzeback, William, Kleinman, Scott J., Kollatschny, Wolfram, Krzesiński, Jurek, Leloudas, Giorgos, Long, Daniel C., Lucey, John, Malanushenko, Elena, Malanushenko, Viktor, McMillan, Russet J., Morgan, Christopher W., Morokuma, Tomoki, Nitta, Atsuko, Ostman, Linda, Pan, Kaike, Romer, A. Kathy, Saurage, Gabrelle, Schlesinger, Katie, Snedden, Stephanie A., Sollerman, Jesper, Stritzinger, Maximilian, Watson, Linda C., Watters, Shannon, Wheeler, J. Craig, and York, Donald

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra., Comment: Accepted for publication in The Astronomical Journal(47pages, 9 figures)

Published
2008
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15. KELT-8b: A HIGHLY INFLATED TRANSITING HOT JUPITER AND A NEW TECHNIQUE FOR EXTRACTING HIGH-PRECISION RADIAL VELOCITIES FROM NOISY SPECTRA

Author

D'Ago, Giuseppe, Zambelli, Roberto, Corfini, Giorgio, Fulton, Benjamin J., Lund, Michael B., Ziegler, Carl, Riddle, Reed, DePoy, Darren L., Law, Nicholas M., Marshall, Jennifer, Siverd, Robert J., Jensen, Eric L.N., Gaudi, B. Scott, Collins, Karen A., Eastman, Jason D., McLeod, Kim K., Manner, Mark, Gregorio, Joao, Howard, Andrew W., Penev, Kaloyan, Stassun, Keivan G., Stevens, Daniel J., Bieryla, Allyson, Latham, David W., Kielkopf, John F., Oberst, Thomas E., Beatty, Thomas G., Penny, Matthew T., Rodriguez, Joseph E., Pepper, Joshua, Reed, Phillip A., and Baranec, Christoph

Subjects
13. Climate action, Astrophysics::Earth and Planetary Astrophysics
Abstract

We announce the discovery of a highly inflated transiting hot Jupiter by the KELT-North survey. A global analysis including constraints from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly evolved, G dwarf with K, , , an inferred mass , and radius . The planetary companion has a mass MJ, radius RJ, surface gravity , and density g cm−3. The planet is on a roughly circular orbit with semimajor axis AU and eccentricity . The best-fit linear ephemeris is and days. This planet is one of the most inflated of all known transiting exoplanets, making it one of the few members of a class of extremely low density, highly irradiated gas giants. The low stellar and large implied radius are supported by stellar density constraints from follow-up light curves, as well as an evolutionary and space motion analysis. We also develop a new technique to extract high-precision radial velocities from noisy spectra that reduces the observing time needed to confirm transiting planet candidates. This planet boasts deep transits of a bright star, a large inferred atmospheric scale height, and a high equilibrium temperature of K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.

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