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31 results on '"Smith, R. Chris"'

1. The essence supernova survey: survey optimization, observations, and supernova photometry

Author

Miknaitis, Gajus, Pignata, Guiliano, Rest, Armin, Wood-Vasey, W. Michael, Blondin, Stephanie, Challis, Peter M, Smith, R. Chris, Stubbs, Christopher, Suntzeff, Nicholas B, Foley, Ryan, Matheson, Thomas, Tonry, John, Aguilera, Claudio, Blackman, Joshua, Becker, Andrew C, Clocchiatti, Alejandro, Covarrubias, Ricardo, Davis, T M, Filippenko, Alexei, Garg, Armin, Garnavich, Peter M, Hicken, Malcolm, Jha, Saurabh, Krisciunas, Kevin, Kirshner, Robert P, Leibundgut, Bruno, Li, Weidong, Miceli, Anthony, Narayan, Gautham, Prieto, Jose Luis, Riess, Adam, Salvo, Maria, Schmidt, Brian, Sollerman, Jesper, Spyromilio, Jason, Zenteno, Alfredo, Miknaitis, Gajus, Pignata, Guiliano, Rest, Armin, Wood-Vasey, W. Michael, Blondin, Stephanie, Challis, Peter M, Smith, R. Chris, Stubbs, Christopher, Suntzeff, Nicholas B, Foley, Ryan, Matheson, Thomas, Tonry, John, Aguilera, Claudio, Blackman, Joshua, Becker, Andrew C, Clocchiatti, Alejandro, Covarrubias, Ricardo, Davis, T M, Filippenko, Alexei, Garg, Armin, Garnavich, Peter M, Hicken, Malcolm, Jha, Saurabh, Krisciunas, Kevin, Kirshner, Robert P, Leibundgut, Bruno, Li, Weidong, Miceli, Anthony, Narayan, Gautham, Prieto, Jose Luis, Riess, Adam, Salvo, Maria, Schmidt, Brian, Sollerman, Jesper, Spyromilio, Jason, and Zenteno, Alfredo

Abstract

We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w = P/(pc 2). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4 m telescope, measuring the luminosity distances and redshifts for Supernovae at modest redshifts (z ≈ 0.5± 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find Supernovae automatically and in nearly real time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their apparent brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4 m telescope's natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 Type Ia supernovae, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for all of the Type Ia Supernovae found by ESSENCE and used in our measurement of w, presented in a companion paper by Wood-Vasey and coworkers.

Published
2007

2. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes

Author

Davis, T M, Mortsell, E, Sollerman, Jesper, Becker, Andrew C, Blondin, Stephanie, Challis, Peter M, Clocchiatti, Alejandro, Filippenko, Alexei, Foley, Ryan, Garnavich, Peter M, Jha, S, Krisciunas, Kevin, Kirshner, Robert P, Leibundgut, Bruno, Li, W, Matheson, Thomas, Miknaitis, Gajus, Pignata, Guiliano, Rest, Armin, Riess, Adam, Schmidt, Brian, Smith, R. Chris, Spyromilio, Jason, Stubbs, Christopher, Suntzeff, Nicholas B, Tonry, John, Wood-Vasey, W. Michael, Zenteno, Alfredo, Davis, T M, Mortsell, E, Sollerman, Jesper, Becker, Andrew C, Blondin, Stephanie, Challis, Peter M, Clocchiatti, Alejandro, Filippenko, Alexei, Foley, Ryan, Garnavich, Peter M, Jha, S, Krisciunas, Kevin, Kirshner, Robert P, Leibundgut, Bruno, Li, W, Matheson, Thomas, Miknaitis, Gajus, Pignata, Guiliano, Rest, Armin, Riess, Adam, Schmidt, Brian, Smith, R. Chris, Spyromilio, Jason, Stubbs, Christopher, Suntzeff, Nicholas B, Tonry, John, Wood-Vasey, W. Michael, and Zenteno, Alfredo

Abstract

The first cosmological results from the ESSENCE supernova survey (Wood-Vasey and coworkers) are extended to a wider range of cosmological models including dynamical dark energy and nonstandard cosmological models. We fold in a greater number of external data sets such as the recent Higher-z release of high-redshift supernovae (Riess and coworkers), as well as several complementary cosmological probes. Model comparison statistics such as the Bayesian and Akaike information criteria are applied to gauge the worth of models. These statistics favor models that give a good fit with fewer parameters. Based on this analysis, the preferred cosmological model is the flat cosmological constant model, where the expansion history of the universe can be adequately described with only one free parameter describing the energy content of the universe. Among the more exotic models that provide good fits to the data, we note a preference for models whose best-fit parameters reduce them to the cosmological constant model.

Published
2007

3. Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey

Author

Rest, Armin, Stubbs, Christopher W, Becker, Andrew C, Miknaitis, Gajus, Miceli, Anthony, Covarrubias, Ricardo, Hawley, Suzanne, Smith, R. Chris, Suntzeff, Nicholas B, Olsen, K, Prieto, Jose Luis, Hiriart, R, Welch, D L, Cook, Kem H, Nikolaev, S, Huber, M, Prochtor, G, Clocchiatti, Alejandro, Minniti, Dante, Garg, Armin, Challis, Peter M, Keller, Stefan, Schmidt, Brian, Rest, Armin, Stubbs, Christopher W, Becker, Andrew C, Miknaitis, Gajus, Miceli, Anthony, Covarrubias, Ricardo, Hawley, Suzanne, Smith, R. Chris, Suntzeff, Nicholas B, Olsen, K, Prieto, Jose Luis, Hiriart, R, Welch, D L, Cook, Kem H, Nikolaev, S, Huber, M, Prochtor, G, Clocchiatti, Alejandro, Minniti, Dante, Garg, Armin, Challis, Peter M, Keller, Stefan, and Schmidt, Brian

Abstract

Characterizing the nature and spatial distribution of the lensing objects that produce the previously measured microlensing optical depth toward the Large Magellanic Cloud (LMC) remains an open problem. We present an appraisal of the ability of the SuperMACHO Project, a next-generation microlensing survey directed toward the LMC, to discriminate between various proposed lensing populations. We consider two scenarios: lensing by a uniform foreground screen of objects and self-lensing by LMC stars. The optical depth for "screen lensing" is essentially constant across the face of the LMC, whereas the optical depth for self-lensing shows a strong spatial dependence. We have carried out extensive simulations, based on data obtained during the first year of the project, to assess the SuperMACHO survey's ability to discriminate between these two scenarios. In our simulations we predict the expected number of observed microlensing events for various LMC models for each of our fields by adding artificial stars to the images and estimating the spatial and temporal efficiency of detecting microlensing events using Monte Carlo methods. We find that the event rate itself shows significant sensitivity to the choice of the LMC luminosity function, limiting the conclusions that can be drawn from the absolute rate. If instead we determine the differential event rate across the LMC, we will decrease the impact of these systematic biases and render our conclusions more robust. With this approach the SuperMACHO Project should be able to distinguish between the two categories of lens populations. This will provide important constraints on the nature of the lensing objects and their contributions to the Galactic dark matter halo.

Published
2005

4. Twenty-Three High-Redshift Supernovae from the Institute for Astronomy Deep Survey: Doubling the Supernova Sample at z > 0.7

Author

Barris, Brian, Tonry, John, Blondin, Stephane, Challis, Peter M, Chornock, Ryan, Clocchiatti, Alejandro, Filippenko, Alexei, Garnavich, Peter M, Holland, Stephen T., Jha, Saurabh, Kirshner, Robert P, Krisciunas, Kevin, Leibundgut, Bruno, Li, Weidong, Matheson, Thomas, Miknaitis, Gajus, Riess, Adam, Schmidt, Brian, Smith, R. Chris, Solheim, Jesper, Spyromilio, Jason, Stubbs, Christopher W, Suntzeff, Nicholas B, Aussel, Hervé, Chambers, K C, Connelley, M S, Donovan, D, Henry, Jasmine, Kaiser, Nick, Liu, Michael C, Martin, Eduardo, Wainscoat, Richard J, Barris, Brian, Tonry, John, Blondin, Stephane, Challis, Peter M, Chornock, Ryan, Clocchiatti, Alejandro, Filippenko, Alexei, Garnavich, Peter M, Holland, Stephen T., Jha, Saurabh, Kirshner, Robert P, Krisciunas, Kevin, Leibundgut, Bruno, Li, Weidong, Matheson, Thomas, Miknaitis, Gajus, Riess, Adam, Schmidt, Brian, Smith, R. Chris, Solheim, Jesper, Spyromilio, Jason, Stubbs, Christopher W, Suntzeff, Nicholas B, Aussel, Hervé, Chambers, K C, Connelley, M S, Donovan, D, Henry, Jasmine, Kaiser, Nick, Liu, Michael C, Martin, Eduardo, and Wainscoat, Richard J

Abstract

We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range of z = 0.34-1.03, nine of which are unambiguously classified as Type la. These SNe were discovered during the IfA Deep Survey, which began in 2001

Published
2004

5. Calibration of Nebular Emission-Line Diagnostics: I. Stellar Effective Temperatures

Author

Oey, M, Smith, R. Chris, Dopita, Michael, Oey, M, Smith, R. Chris, and Dopita, Michael

Abstract

We present a detailed comparison of optical H II region spectra to photoionization models based on modern stellar atmosphere models. We examine both spatially resolved and integrated emission-line spectra of the H II regions DEM L323, DEM L243, DEM L199

Published
2000

6. Optical Spectra of Type 1a Supernovae at z = 0.46 and z = 1.2

Author

Coil, Alison L, Matheson, Thomas, Filippenko, Alexei, Leonard, D C, Tonry, John, Reiss, D, Challis, Peter M, Clocchiatti, Alejandro, Garnavich, Peter M, Hogan, Craig, Jha, Saurabh, Kirshner, Robert P, Leibundgut, Bruno, Phillips, Matthew R, Schmidt, Brian, Smith, R. Chris, Soderberg, A M, Spyromilio, Jason, Stubbs, Christopher W, Suntzeff, Nicholas B, Woudt, P, Schommer, Robert, Coil, Alison L, Matheson, Thomas, Filippenko, Alexei, Leonard, D C, Tonry, John, Reiss, D, Challis, Peter M, Clocchiatti, Alejandro, Garnavich, Peter M, Hogan, Craig, Jha, Saurabh, Kirshner, Robert P, Leibundgut, Bruno, Phillips, Matthew R, Schmidt, Brian, Smith, R. Chris, Soderberg, A M, Spyromilio, Jason, Stubbs, Christopher W, Suntzeff, Nicholas B, Woudt, P, and Schommer, Robert

Abstract

We present optical spectra, obtained with the Keck 10 m telescope, of two high-redshift Type Ia supernovae (SNe Ia) discovered by the High-z Supernova Search Team: SN 1999ff at z = 0.455 and SN 1999fv at z ∼ 1.2, the highest redshift published SN Ia spe

Published
2000

7. Toward More Precise Survey Photometry for PanSTARRS and LSST: Measuring Directly the Optical Transmission Spectrum of the Atmosphere

Author

Stubbs, Christopher W., primary, High, F. William, additional, George, Matthew R., additional, DeRose, Kimberly L., additional, Blondin, Stéphane, additional, Tonry, John L., additional, Chambers, Kenneth C., additional, Granett, Benjamin R., additional, Burke, David L., additional, and Smith, R. Chris, additional

Published
2007
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10. Spectroscopy of High-Redshift Supernovae from the ESSENCE Project: The First 2 YearsBased in part on observations obtained at the Cerro Tololo Inter-American Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the National Science Foundation (NSF); the European Southern Observatory, Chile (ESO Programme 170.A-0519); the Gemini Observatory, which is operated by AURA under a cooperative agreement with the NSF on behalf of the Gemini partnership (the NSF [United States], the Particle Physics and Astronomy Research Council [United Kingdom], the National Research Council [Canada], CONICYT [Chile], the Australian Research Council [Australia], CNPq [Brazil], and CONICET [Argentina] [programs GN-2002B-Q-14, GN-2003B-Q-14, and GS-2003B-Q-11]); the Magellan Telescopes at Las Campanas Observatory; the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona; and the F. L. Whipple Observatory, which is operated by the Smithsonian Astrophysical Observatory. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration; the Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Author

Matheson, Thomas, Blondin, Stéphane, Foley, Ryan J., Chornock, Ryan, Filippenko, Alexei V., Leibundgut, Bruno, Smith, R. Chris, Sollerman, Jesper, Spyromilio, Jason, Kirshner, Robert P., Clocchiatti, Alejandro, Aguilera, Claudio, Barris, Brian, Becker, Andrew C., Challis, Peter, Covarrubias, Ricardo, Garnavich, Peter, Hicken, Malcolm, Jha, Saurabh, and Krisciunas, Kevin

Published
2005
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11. Twenty-Three High-Redshift Supernovae from the Institute for Astronomy Deep Survey: Doubling the Supernova Sample at z > 0.7 CFHT: Based in part on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. CTIO: Based in part on observations taken at the Cerro Tololo Inter-American Observatory. Keck: Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Magellan: Based in part on observations from the 6.5 m Baade telescope operated by the Observatories of the Carnegie Institution of Washington for the Magellan Consortium, a collaboration between the Carnegie Observatories, the University of Arizona, Harvard University, the University of Michigan, and the Massachusetts Institute of Technology. UH: Based in part on observations with the University of Hawaii 2.2 m telescope at Mauna Kea Observatory, Institute for Astronomy, University of Hawaii. VLT: Based in part on observations obtained at the European Southern Observatory, Paranal, Chile, under programs ESO 68.A-0427. Based in part on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. This research is primarily associated with proposal GO-09118.

Author

Barris, Brian J., Tonry, John L., Blondin, Stéphane, Challis, Peter, Chornock, Ryan, Clocchiatti, Alejandro, Filippenko, Alexei V., Garnavich, Peter, Holland, Stephen T., Jha, Saurabh, Kirshner, Robert P., Krisciunas, Kevin, Leibundgut, Bruno, Li, Weidong, Matheson, Thomas, Miknaitis, Gajus, Riess, Adam G., Schmidt, Brian P., Smith, R. Chris, and Sollerman, Jesper

Published
2004
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13. Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant.

Author

Riess, Adam G., Filippenko, Alexei V., Challis, Peter, Clocchiatti, Alejandro, Diercks, Alan, Garnavich, Peter M., Gilliland, Ron L., Hogan, Craig J., Jha, Saurabh, Kirshner, Robert P., Leibundgut, B., Phillips, M. M., Reiss, David, Schmidt, Brian P., Schommer, Robert A., Smith, R. Chris, Spyromilio, J., Stubbs, Christopher, Suntzeff, Nicholas B., and Tonry, John

Published
1998
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14. The High-Z Supernova Search: Measuring Cosmic Deceleration and Global Curvature of the Universe Using Type Ia SupernovaeThis work is based in part on observations at the European Southern Observatory, La Silla, Chile.

Author

Schmidt, Brian P., Suntzeff, Nicholas B., Phillips, M. M., Schommer, Robert A., Clocchiatti, Alejandro, Kirshner, Robert P., Garnavich, Peter, Challis, Peter, Leibundgut, B., Spyromilio, J., Riess, Adam G., Filippenko, Alexei V., Hamuy, Mario, Smith, R. Chris, Hogan, Craig, Stubbs, Christopher, Diercks, Alan, Reiss, David, Gilliland, Ron, and Tonry, John

Published
1998
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16. All-Weather Calibration of Wide-Field Optical and NIR Surveys

Author

Burke, David L., Saha, Abhijit, Claver, Jenna, Axelrod, T., Claver, Chuck, DePoy, Darren, Ivezić, Željko, Jones, Lynne, Smith, R. Chris, and Stubbs, Christopher William

Subjects
atmospheric effects, methods: observational, surveys, techniques: photometric
Abstract

The science goals for ground-based large-area surveys, such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope, require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of a percent or better. This performance will need to be achieved with data taken over the course of many years, and often in less than ideal conditions. This paper describes a strategy to achieve precise internal calibration of imaging survey data taken in less than "photometric" conditions, and reports results of an observational study of the techniques needed to implement this strategy. We find that images of celestial fields used in this case study with stellar densities ~1 arcmin–2 and taken through cloudless skies can be calibrated with relative precision ~0.5% (reproducibility). We report measurements of spatial structure functions of cloud absorption observed over a range of atmospheric conditions, and find it possible to achieve photometric measurements that are reproducible to 1% in images that were taken through cloud layers that transmit as little as 25% of the incident optical flux (1.5 magnitudes of extinction). We find, however, that photometric precision below 1% is impeded by the thinnest detectable cloud layers. We comment on implications of these results for the observing strategies of future surveys., Astronomy

Published
2013
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20. Light Curves of Type Ia Supernovae from Near the Time of Explosion.

Author

Garg, Arti, Stubbs, Christopher W., Challis, Peter, Wood-Vasey, W. Michael, Blondin, Stéphane, Huber, Mark E., Cook, Kem, Nikolaev, Sergei, Rest, Armin, Smith, R. Chris, Olsen, Knut, Suntzeff, Nicholas B., Aguilera, Claudio, Prieto, Jose Luis, Becker, Andrew, Miceli, Antonino, Miknaitis, Gajus, Clocchiatti, Alejandro, Minniti, Dante, and Morelli, Lorenzo

Published
2007
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26. Optical Spectra of Type Ia Supernovae at z = 0.46 and z = 1.2.

Author

Coil, Alison L., Matheson, Thomas, Filippenko, Alexei V., Leonard, Douglas C., Tonry, John, Riess, Adam G., Challis, Peter, Clocchiatti, Alejandro, Garnavich, Peter M., Hogan, Craig J., Jha, Saurabh, Kirshner, Robert P., Leibundgut, B., Phillips, M. M., Schmidt, Brian P., Schommer, Robert A., Smith, R. Chris, Soderberg, Alicia M., Spyromilio, J., and Stubbs, Christopher

Published
2000
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27. Tests of the Accelerating Universe with Near-Infrared Observations of a High-Redshift Type Ia Supernova.

Author

Riess, Adam G., Filippenko, Alexei V., Liu, Michael C., Challis, Peter, Clocchiatti, Alejandro, Diercks, Alan, Garnavich, Peter M., Hogan, Craig J., Jha, Saurabh, Kirshner, Robert P., Leibundgut, B., Phillips, M. M., Reiss, David, Schmidt, Brian P., Schommer, Robert A., Smith, R. Chris, Spyromilio, J., Stubbs, Christopher, Suntzeff, Nicholas B., and Tonry, John

Published
2000
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29. Supernova Limits on the Cosmic Equation of State.

Author

Garnavich, Peter M., Jha, Saurabh, Challis, Peter, Clocchiatti, Alejandro, Diercks, Alan, Filippenko, Alexei V., Gilliland, Ron L., Hogan, Craig J., Kirshner, Robert P., Leibundgut, Bruno, Phillips, M. M., Reiss, David, Riess, Adam G., Schmidt, Brian P., Schommer, Robert A., Smith, R. Chris, Spyromilio, Jason, Stubbs, Chris, Suntzeff, Nicholas B., and Tonry, John

Published
1998
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