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Jeffrey D. Crane
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The Observatories of the Carnegie Institution for Science
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Earth and Planetary Astrophysics (11)
 
Solar and Stellar Astrophysics (11)
 
Astrophysics of Galaxies (8)
 
Astrophysics (8)
 
Cosmology and Nongalactic Astrophysics (5)
 
Instrumentation and Methods for Astrophysics (2)

Publications Authored By Jeffrey D. Crane

2017Feb
Authors: Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Timothy C. Beers, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael Blomqvist, Adam S. Bolton, Médéric Boquien, Jura Borissova, Remco van den Bosch, Jo Bovy, William N. Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Adam J. Burgasser, Etienne Burtin, Nicolás G. Busca, Michele Cappellari, Maria Leticia Delgado Carigi, Joleen K. Carlberg, Aurelio Carnero Rosell, Ricardo Carrera, Brian Cherinka, Edmond Cheung, Yilen Gómez Maqueo Chew, Cristina Chiappini, Peter Doohyun Choi, Drew Chojnowski, Chia-Hsun Chuang, Haeun Chung, Rafael Fernando Cirolini, Nicolas Clerc, Roger E. Cohen, Johan Comparat, Luiz da Costa, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Rupert A. C. Croft, Irene Cruz-Gonzalez, Daniel Garrido Cuadra, Katia Cunha, Guillermo J. Damke, Jeremy Darling, Roger Davies, Kyle Dawson, Axel de la Macorra, Nathan De Lee, Timothée Delubac, Francesco Di Mille, Aleks Diamond-Stanic, Mariana Cano-Díaz, John Donor, Juan José Downes, Niv Drory, Hélion du Mas des Bourboux, Christopher J. Duckworth, Tom Dwelly, Jamie Dyer, Garrett Ebelke, Daniel J. Eisenstein, Eric Emsellem, Mike Eracleous, Stephanie Escoffier, Michael L. Evans, Xiaohui Fan, Emma Fernández-Alvar, J. G. Fernandez-Trincado, Diane K. Feuillet, Alexis Finoguenov, Scott W. Fleming, Andreu Font-Ribera, Alexander Fredrickson, Gordon Freischlad, Peter M. Frinchaboy, Lluís Galbany, R. Garcia-Dias, D. A. García-Hernández, Patrick Gaulme, Doug Geisler, Joseph D. Gelfand, Héctor Gil-Marín, Bruce A. Gillespie, Daniel Goddard, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul J. Green, Catherine J. Grier, James E. Gunn, Hong Guo, Julien Guy, Alex Hagen, ChangHoon Hahn, Matthew Hall, Paul Harding, Sten Hasselquist, Suzanne L. Hawley, Fred Hearty, Jonay I. Gonzalez Hernández, Shirley Ho, David W. Hogg, Kelly Holley-Bockelmann, Jon A. Holtzman, Parker H. Holzer, Joseph Huehnerhoff, Timothy A. Hutchinson, Ho Seong Hwang, Héctor J. Ibarra-Medel, Gabriele da Silva Ilha, Inese I. Ivans, KeShawn Ivory, Kelly Jackson, Trey W. Jensen, Jennifer A. Johnson, Amy Jones, Henrik Jönsson, Eric Jullo, Vikrant Kamble, Karen Kinemuchi, David Kirkby, Francisco-Shu Kitaura, Mark Klaene, Gillian R. Knapp, Jean-Paul Kneib, Juna A. Kollmeier, Ivan Lacerna, Richard R. Lane, Dustin Lang, David R. Law, Daniel Lazarz, Jean-Marc Le Goff, Fu-Heng Liang, Cheng Li, Hongyu LI, Marcos Lima, Lihwai Lin, Yen-Ting Lin, Sara Bertran de Lis, Chao Liu, Miguel Angel C. de Icaza Lizaola, Dan Long, Sara Lucatello, Britt Lundgren, Nicholas K. MacDonald, Alice Deconto Machado, Chelsea L. MacLeod, Suvrath Mahadevan, Marcio Antonio Geimba Maia, Roberto Maiolino, Steven R. Majewski, Elena Malanushenko, Viktor Malanushenko, Arturo Manchado, Shude Mao, Claudia Maraston, Rui Marques-Chaves, Karen L. Masters, Cameron K. McBride, Richard M. McDermid, Brianne McGrath, Ian D. McGreer, Nicolás Medina Peña, Matthew Melendez, Andrea Merloni, Michael R. Merrifield, Szabolcs Meszaros, Andres Meza, Ivan Minchev, Dante Minniti, Takamitsu Miyaji, Surhud More, John Mulchaey, Francisco Müller-Sánchez, Demitri Muna, Ricardo R. Munoz, Adam D. Myers, Preethi Nair, Kirpal Nandra, Janaina Correa do Nascimento, Alenka Negrete, Melissa Ness, Jeffrey A. Newman, Robert C. Nichol, David L. Nidever, Christian Nitschelm, Pierros Ntelis, Julia E. O'Connell, Ryan J. Oelkers, Audrey Oravetz, Daniel Oravetz, Zach Pace, Nelson Padilla, Nathalie Palanque-Delabrouille, Pedro Alonso Palicio, Kaike Pan, Taniya Parikh, Isabelle Pâris, Changbom Park, Alim Y. Patten, Sebastien Peirani, Marcos Pellejero-Ibanez, Samantha Penny, Will J. Percival, Ismael Perez-Fournon, Patrick Petitjean, Matthew M. Pieri, Marc Pinsonneault, Alice Pisani, Radosław Poleski, Francisco Prada, Abhishek Prakash, Anna Bárbara de Andrade Queiroz, M. Jordan Raddick, Anand Raichoor, Sandro Barboza Rembold, Hannah Richstein, Rogemar A. Riffel, Rogério Riffel, Hans-Walter Rix, Annie C. Robin, Constance M. Rockosi, Sergio Rodríguez-Torres, A. Roman-Lopes, Carlos Román-Zúñiga, Margarita Rosado, Ashley J. Ross, Graziano Rossi, John Ruan, Rossana Ruggeri, Eli S. Rykoff, Salvador Salazar-Albornoz, Mara Salvato, Ariel G. Sánchez, David Sánchez Aguado, José R. Sánchez-Gallego, Felipe A. Santana, Basílio Xavier Santiago, Conor Sayres, Ricardo P. Schiavon, Jaderson da Silva Schimoia, Edward F. Schlafly, David J. Schlegel, Donald P. Schneider, Mathias Schultheis, William J. Schuster, Axel Schwope, Hee-Jong Seo, Zhengyi Shao, Shiyin Shen, Matthew Shetrone, Michael Shull, Joshua D. Simon, Danielle Skinner, M. F. Skrutskie, Anže Slosar, Verne V. Smith, Jennifer S. Sobeck, Flavia Sobreira, Garrett Somers, Diogo Souto, David V. Stark, Keivan Stassun, Fritz Stauffer, Matthias Steinmetz, Thaisa Storchi-Bergmann, Alina Streblyanska, Guy S. Stringfellow, Genaro Suárez, Jing Sun, Nao Suzuki, Laszlo Szigeti, Manuchehr Taghizadeh-Popp, Baitian Tang, Charling Tao, Jamie Tayar, Mita Tembe, Johanna Teske, Aniruddha R. Thakar, Daniel Thomas, Benjamin A. Thompson, Jeremy L. Tinker, Patricia Tissera, Rita Tojeiro, Hector Hernandez Toledo, Sylvain de la Torre, Christy Tremonti, Nicholas W. Troup, Octavio Valenzuela, Inma Martinez Valpuesta, Jaime Vargas-González, Mariana Vargas-Magaña, Jose Alberto Vazquez, Sandro Villanova, M. Vivek, Nicole Vogt, David Wake, Rene Walterbos, Yuting Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Kyle B. Westfall, David G. Whelan, Vivienne Wild, John Wilson, W. M. Wood-Vasey, Dominika Wylezalek, Ting Xiao, Renbin Yan, Meng Yang, Jason E. Ybarra, Christophe Yèche, Nadia Zakamska, Olga Zamora, Pauline Zarrouk, Gail Zasowski, Kai Zhang, Gong-Bo Zhao, Zheng Zheng, Zhi-Min Zhou, Guangtun B. Zhu, Manuela Zoccali, Hu Zou

We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratio in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially-resolved spectroscopy for thousands of nearby galaxies (median redshift of z = 0. Read More

We present a new precision radial velocity (RV) dataset that reveals multiple planets orbiting the stars in the $\sim$360 AU, G2$+$G2 "twin" binary HD 133131AB. Our 6 years of high-resolution echelle observations from MIKE and 5 years from PFS on the Magellan telescopes indicate the presence of two eccentric planets around HD 133131A with minimum masses of 1.43$\pm$0. Read More

2016Aug
Authors: SDSS Collaboration, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott Anderson, Brett H. Andrews, Alfonso Aragon-Salamanca, Maria Argudo-Fernandez, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Beatriz Barbuy, Kat Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Sarbani Basu, Dominic Bates, Giuseppina Battaglia, Falk Baumgarten, Julien Baur, Julian Bautista, Timothy C. Beers, Francesco Belfiore, Matthew Bershady, Sara Bertran de Lis, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael Blanton, Michael Blomqvist, Adam S. Bolton, J. Borissova, Jo Bovy, William Nielsen Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Etienne Burtin, Nicolas G. Busca, Hugo Orlando Camacho Chavez, M. Cano Diaz, Michele Cappellari, Ricardo Carrera, Yanping Chen, Brian Cherinka, Edmond Cheung, Cristina Chiappini, Drew Chojnowski, Chia-Hsun Chuang, Haeun Chung, Rafael Fernando Cirolini, Nicolas Clerc, Roger E. Cohen, Julia M. Comerford, Johan Comparat, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Rupert Croft, Katia Cunha, Luiz da Costa, Gabriele da Silva Ilha, Jeremy Darling, James W. Davidson Jr., Kyle Dawson, Nathan De Lee, Axel de la Macorra, Sylvain de la Torre, Alice Deconto Machado, Timothee Delubac, Aleksandar M. Diamond-Stanic, John Donor, Juan Jose Downes, Niv Drory, Helion du Mas des Bourboux, Cheng Du, Tom Dwelly, Garrett Ebelke, Arthur Eigenbrot, Daniel J. Eisenstein, Yvonne P. Elsworth, Eric Emsellem, Michael Eracleous, Stephanie Escoffier, Michael L. Evans, Jesus Falcon-Barroso, Xiaohui Fan, Ginevra Favole, Emma Fernandez-Alvar, J. G. Fernandez-Trincado, Diane Feuillet, Scott W. Fleming, Andreu Font-Ribera, Gordon Freischlad, Peter Frinchaboy, Hai Fu, Yang Gao, D. A. Garcia-Hernandez, Ana E. Garcia Perez, Rafael A. Garcia, R. Garcia-Dias, Patrick Gaulme, Junqiang Ge, Douglas Geisler, Hector Gil Marin, Bruce Gillespie, Leo Girardi, Daniel Goddard, Yilen Gomez Maqueo Chew, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul Green, Catherine J. Grier, Thomas Grier, Hong Guo, Julien Guy, Alex Hagen, Matt Hall, Paul Harding, R. E. Harley, Sten Hasselquist, Suzanne Hawley, Christian R. Hayes, Fred Hearty, Saskia Hekker, Hector Hernandez Toledo, Shirley Ho, David W. Hogg, Kelly Holley-Bockelmann, Jon A. Holtzman, Parker H. Holzer, Jian Hu, Daniel Huber, Timothy Alan Hutchinson, Ho Seong Hwang, Hector J. Ibarra-Medel, Inese I. Ivans, KeShawn Ivory, Kurt Jaehnig, Trey W. Jensen, Jennifer A. Johnson, Amy Jones, Eric Jullo, T. Kallinger, Karen Kinemuchi, David Kirkby, Mark Klaene, Jean-Paul Kneib, Juna A. Kollmeier, Ivan Lacerna, Richard R. Lane, Dustin Lang, Pierre Laurent, David R. Law, Jean-Marc Le Goff, Alexie Leauthaud, Cheng Li, Ran Li, Chen Li, Niu Li, Fu-Heng Liang, Yu Liang, Marcos Lima, Lihwai Lin, Lin Lin, Yen-Ting Lin, Dan Long, Sara Lucatello, Nicholas MacDonald, Chelsea L. MacLeod, J. Ted Mackereth, Suvrath Mahadevan, Marcio Antonio-Geimba Maia, Roberto Maiolino, Steven R. Majewski, Olena Malanushenko, Nicolas Dullius Mallmann, Arturo Manchado, Claudia Maraston, Rui Marques-Chaves, Inma Martinez Valpuesta, Karen L. Masters, Savita Mathur, Ian D. McGreer, Andrea Merloni, Michael R. Merrifield, Szabolcs Meszaros, Andres Meza, Andrea Miglio, Ivan Minchev, Karan Molaverdikhani, Antonio D. Montero-Dorta, Benoit Mosser, Demitri Muna, Adam Myers, Preethi Nair, Kirpal Nandra, Melissa Ness, Jeffrey A. Newman, Robert C. Nichol, David L. Nidever, Christian Nitschelm, Julia O'Connell, Audrey Oravetz, Nelson Padilla, Nathalie Palanque-Delabrouille, Kaike Pan, John Parejko, Isabelle Paris, John A. Peacock, Sebastien Peirani, Marcos Pellejero-Ibanez, Samantha Penny, Will J. Percival, Jeffrey W. Percival, Ismael Perez-Fournon, Patrick Petitjean, Matthew Pieri, Marc H. Pinsonneault, Alice Pisani, Francisco Prada, Abhishek Prakash, Natalie Price-Jones, M. Jordan Raddick, Mubdi Rahman, Anand Raichoor, Sandro Barboza Rembold, A. M. Reyna, James Rich, Hannah Richstein, Jethro Ridl, Rogerio Riffel, Rogemar A. Riffel, Hans-Walter Rix, Annie C. Robin, Constance M. Rockosi, Sergio Rodriguez-Torres, Thaise S. Rodrigues, Natalie Roe, A. Roman Lopes, Carlos Roman-Zuniga, Ashley J. Ross, Graziano Rossi, John Ruan, Rossana Ruggeri, Jessie C. Runnoe, Salvador Salazar-Albornoz, Mara Salvato, Ariel G. Sanchez, Sebastian F. Sanchez, Jose R. Sanchez-Gallego, Basilio Xavier Santiago, Ricardo Schiavon, Jaderson S. Schimoia, Eddie Schlafly, David J. Schlegel, Donald P. Schneider, Ralph Schoenrich, Mathias Schultheis, Axel Schwope, Hee-Jong Seo, Aldo Serenelli, Branimir Sesar, Zhengyi Shao, Matthew Shetrone, Michael Shull, Victor Silva Aguirre, M. F. Skrutskie, Anže Slosar, Michael Smith, Verne V. Smith, Jennifer Sobeck, Garrett Somers, Diogo Souto, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Thaisa Storchi Bergmann, Michael A. Strauss, Alina Streblyanska, Guy S. Stringfellow, Genaro Suarez, Jing Sun, Manuchehr Taghizadeh-Popp, Baitian Tang, Charling Tao, Jamie Tayar, Mita Tembe, Daniel Thomas, Jeremy Tinker, Rita Tojeiro, Christy Tremonti, Nicholas Troup, Jonathan R. Trump, Eduardo Unda-Sanzana, O. Valenzuela, Remco van den Bosch, Mariana Vargas-Magana, Jose Alberto Vazquez, Sandro Villanova, M. Vivek, Nicole Vogt, David Wake, Rene Walterbos, Yuting Wang, Enci Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Kyle B. Westfall, David G. Whelan, Eric Wilcots, Vivienne Wild, Rob A. Williams, John Wilson, W. M. Wood-Vasey, Dominika Wylezalek, Ting Xiao, Renbin Yan, Meng Yang, Jason E. Ybarra, Christophe Yeche, Fang-Ting Yuan, Nadia Zakamska, Olga Zamora, Gail Zasowski, Kai Zhang, Cheng Zhao, Gong-Bo Zhao, Zheng Zheng, Zheng Zheng, Zhi-Min Zhou, Guangtun Zhu, Joel C. Zinn, Hu Zou

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2, MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. Read More

In an effort to measure the masses of planets discovered by the NASA {\it K2} mission, we have conducted precise Doppler observations of five stars with transiting planets. We present the results of a joint analysis of these new data and previously published Doppler data. The first star, an M dwarf known as K2-3 or EPIC~201367065, has three transiting planets ("b", with radius $2. Read More

We present a multiplexed, high-resolution (R~50,000 median) spectroscopic survey designed to detect exoplanet candidates in two southern star clusters (NGC 2516 and NGC 2422) using the Michigan/Magellan Fiber System (M2FS) on the Magellan/Clay telescope at Las Campanas Observatory. With 128 available fibers in our observing mode, we are able to target every star in the core half-degree of each cluster that could plausibly be a solar-analog member. Our template-based spectral fits provide precise measurements of fundamental stellar properties - $T_{eff}$ ($\pm$30 K), [Fe/H] and [$\alpha$/Fe] ($\pm$0. Read More

2016Jan
Affiliations: 1U. Michigan, JINA-CEE, 2U. Michigan, 3U. Michigan, 4U. Michigan, 5U. Michigan, 6Carnegie Observatories, 7U. Michigan, 8LSST, Steward Observatory, 9Steward Observatory, 10Carnegie Observatories, 11Carnegie Observatories, 12U. Michigan, 13Carnegie Mellon U.

The ultra-faint dwarf galaxy Reticulum 2 (Ret 2) was recently discovered in images obtained by the Dark Energy Survey. We have observed the four brightest red giants in Ret 2 at high spectral resolution using the Michigan/Magellan Fiber System. We present detailed abundances for as many as 20 elements per star, including 12 elements heavier than the Fe group. Read More

2015Oct
Affiliations: 1University of Michigan, 2University of Michigan, 3University of Michigan, 4University of Michigan, 5Carnegie Observatories, 6Carnegie Observatories

We present radial velocities, stellar parameters, and detailed abundances of 39 elements derived from high-resolution spectroscopic observations of red giant stars in the luminous, metal-poor globular cluster NGC 5824. We observe 26 stars in NGC 5824 using the Michigan/Magellan Fiber System (M2FS) and two stars using the Magellan Inamori Kyocera Echelle (MIKE) spectrograph. We derive a mean metallicity of [Fe/H]=-1. Read More

We present precise Doppler observations of WASP-47, a transiting planetary system featuring a hot Jupiter with both inner and outer planetary companions. This system has an unusual architecture and also provides a rare opportunity to measure planet masses in two different ways: the Doppler method, and the analysis of transit-timing variations (TTV). Based on the new Doppler data, obtained with the Planet Finder Spectrograph on the Magellan/Clay 6. Read More

A combined effort utilizing spectroscopy and photometry has revealed the existence of a new globular cluster class. These "anomalous" clusters, which we refer to as "iron-complex" clusters, are differentiated from normal clusters by exhibiting large (>0.10 dex) intrinsic metallicity dispersions, complex sub-giant branches, and correlated [Fe/H] and s-process enhancements. Read More

Stellar activity may induce Doppler variability at the level of a few m/s which can then be confused by the Doppler signal of an exoplanet orbiting the star. To first order, linear correlations between radial velocity measurements and activity indices have been proposed to account for any such correlation. The likely presence of two super-Earths orbiting Kapteyn's star was reported in Anglada et al. Read More

A recent analysis comparing the [Na/Fe] distributions of red giant branch (RGB) and asymptotic giant branch (AGB) stars in the Galactic globular cluster NGC 6752 found that the ratio of Na-poor to Na-rich stars changes from 30:70 on the RGB to 100:0 on the AGB. The surprising paucity of Na-rich stars on the AGB in NGC 6752 warrants additional investigations to determine if the failure of a significant fraction of stars to ascend the AGB is an attribute common to all globular clusters. Therefore, we present radial velocities, [Fe/H], and [Na/Fe] abundances for 35 AGB stars in the Galactic globular cluster 47 Tucanae (47 Tuc; NGC 104), and compare the AGB [Na/Fe] distribution with a similar RGB sample published previously. Read More

2014Feb
Affiliations: 1The Observatories of the Carnegie Institution for Science, 2The Observatories of the Carnegie Institution for Science, 3The Observatories of the Carnegie Institution for Science, 4The Observatories of the Carnegie Institution for Science, 5The Observatories of the Carnegie Institution for Science, 6The Observatories of the Carnegie Institution for Science, 7The Observatories of the Carnegie Institution for Science, 8The Observatories of the Carnegie Institution for Science, 9The Observatories of the Carnegie Institution for Science

We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with IMACS on Magellan-Baade. CSI uses a flux-limited sample of galaxies in Spitzer IRAC 3.6micron imaging of SWIRE fields to efficiently trace the stellar mass of average galaxies to z~1. Read More

We report two low mass companions orbiting the nearby K7 dwarf GJ 221 that have emerged from re-analyzing 4.4 years of publicly available HARPS spectra complemented with 2 years of high precision Doppler measurements with Magellan/PFS. The HARPS measurements alone contain the clear signal of a low mass companion with a period of 125 days and a minimum mass of 53. Read More

We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 247 RRc selected from the All Sky Automated Survey (ASAS) for which high-quality light curves, photometry and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey (CARRS). Read More

We provide evidence that the obliquities of stars with close-in giant planets were initially nearly random, and that the low obliquities that are often observed are a consequence of star-planet tidal interactions. The evidence is based on 14 new measurements of the Rossiter-McLaughlin effect (for the systems HAT-P-6, HAT-P-7, HAT-P-16, HAT-P-24, HAT-P-32, HAT-P-34, WASP-12, WASP-16, WASP-18, WASP-19, WASP-26, WASP-31, Gl 436, and Kepler-8), as well as a critical review of previous observations. The low-obliquity (well-aligned) systems are those for which the expected tidal timescale is short, and likewise the high-obliquity (misaligned and retrograde) systems are those for which the expected timescale is long. Read More

We re-analyze 4 years of HARPS spectra of the nearby M1.5 dwarf GJ 667C available through the ESO public archive. The new radial velocity (RV) measurements were obtained using a new data analysis technique that derives the Doppler measurement and other instrumental effects using a least-squares approach. Read More

2012Jan
Affiliations: 1The Observatories of the Carnegie Institution for Science, 2The Observatories of the Carnegie Institution for Science, 3The Observatories of the Carnegie Institution for Science, 4The Observatories of the Carnegie Institution for Science, 5The Observatories of the Carnegie Institution for Science, 6The Observatories of the Carnegie Institution for Science, 7The Observatories of the Carnegie Institution for Science, 8The Observatories of the Carnegie Institution for Science, 9The Observatories of the Carnegie Institution for Science

We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade. By defining a flux-limited sample of galaxies in Spitzer 3.6micron imaging of SWIRE fields, the CSI Survey efficiently traces the stellar mass of average galaxies to z~1. Read More

We measure a tilt of 86+-6 deg between the sky projections of the rotation axis of the WASP-7 star, and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Read More

We present precise radial-velocity measurements of WASP-1 and WASP-2 throughout transits of their giant planets. Our goal was to detect the Rossiter-McLaughlin (RM) effect, the anomalous radial velocity observed during eclipses of rotating stars, which can be used to study the obliquities of planet-hosting stars. For WASP-1 a weak signal of a prograde orbit was detected with ~2sigma confidence, and for WASP-2 no signal was detected. Read More

2009Aug
Affiliations: 1Carnegie Observatories, 2The Ohio State University, 3Carnegie Observatories, 4Carnegie Observatories, 5Carnegie Observatories, 6Carnegie Observatories, 7Carnegie Observatories, 8University of Washington, 9University of Washington

We present spectroscopic confirmation of the "Pisces Overdensity", also known as "Structure J", a photometric overdensity of RR Lyrae stars discovered by the Sloan Digital Sky Survey (SDSS) at an estimated photometric distance of ~85kpc. We measure radial velocities for 8 RR Lyrae stars within Pisces. We find that 5 of the 8 stars have heliocentric radial velocities within a narrow range of -87 km/s < v < -67 km/s, suggesting that the photometric overdensity is mainly due to a physically associated system, probably a dwarf galaxy or a disrupted galaxy. Read More

A new large-area Washington M,T_2+DDO51 filter survey of more than 10 deg^2 around the Carina dSph galaxy reveals a spectroscopically confirmed power law radial density "break" population of Carina giant stars extending several degrees beyond the central King profile. Magellan telescope MIKE spectroscopy establishes the existence of Carina stars to at least 4.5 times its central King limiting radius, r_lim and primarily along Carina's major axis. Read More

We present reliable measurements of the metallicity distribution function (MDF) at different points along the tidal stream of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy, based on high resolution, echelle spectroscopy of candidate M giant members of the Sgr system. The Sgr MDF is found to evolve significantly from a median [Fe/H] ~-0.4 in the core to ~-1. Read More

The Fan Observatory Bench Optical Spectrograph (FOBOS) is intended for single-object optical spectroscopy at moderate resolution (R~1500-3000) using a fiber-fed, bench-mounted design to maintain stability. Whenever possible, the instrument uses off-the-shelf components to maintain a modest cost. FOBOS supports Galactic astronomy projects that require consistently well-measured (~5 km/sec) radial velocities for large numbers of broadly distributed and relatively bright (V<14) stars. Read More

We report here the discovery of an apparent excess of 2MASS M giant candidates with dereddened 0.85 < J-K_S < 1.2 spanning a considerably large area of the celestial sphere between, at least, $100\degr < l < 150\degr$ and $-20\degr > b > -40\degr$, and covering most of the constellations of Triangulum and Andromeda. Read More

We present moderate resolution (~6 km/s) spectroscopy of 284 M giant candidates selected from the Two Micron All Sky Survey photometry. Radial velocities (RVs) are presented for stars mainly in the south, with a number having positions consistent with association to the trailing tidal tail of the Sagittarius (Sgr) dwarf galaxy. The latter show a clear RV trend with orbital longitude, as expected from models of the orbit and destruction of Sgr. Read More

The Galactic Anticenter Stellar Structure (GASS) has been identified with excess surface densities of field stars in several large area sky surveys, and with an unusual, string-like grouping of five globular clusters. At least two of these are diffuse, young ``transitional'' clusters between open and globular types. Here we call attention to the fact that four {\it younger} open or transitional clusters extend the previously identified, string-like cluster grouping, with at least one having a radial velocity consistent with the previously found GASS velocity-longitude trend. Read More

To determine the nature of the recently discovered, ring-like stellar structure at the Galactic anticenter, we have collected spectra of a set of presumed constituent M giants selected from the 2MASS point source catalog. Radial velocities have been obtained for stars spanning ~100 degrees, exhibiting a trend in velocity with Galactic longitude and an estimated dispersion of 20 +/- 4 km/sec. A mean metallicity [Fe/H] = -0. Read More

2003Jul
Affiliations: 1Astronomy Department, University of Virginia, 2Astronomy Department, University of Virginia, 3Astronomy Department, University of Virginia, 4Astronomy Department, University of Virginia
Category: Astrophysics

The recently discovered, ring-like structure just outside the Galactic disk in Monoceros is detected and traced among 2MASS M giant stars. We have developed a method to recover the signature of this structure from the distance probability density function of stars along a given line of sight. Its detection is possible even when the metallicity is unknown, provided that the structure is not too embedded in the disk. Read More