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12 results on '"GARNAVICH, PETER"'

1. Three Gravitationally Lensed Supernovae Behind Clash Galaxy Clusters

Author

Patel, Brandon, McCully, Curtis, Jha, Saurbh W, Rodney, Steven A, Jones, David O, Graur, Or, Merten, Julian, Zitrin, Adi, Riess, Adam G, Matheson, Thomas, Sako, Masao, Holoien, Thomas W. -S, Postman, Marc, Coe, Dan, Bartelmann, Matthias, Balestra, Italo, Benitez, Narciso, Bouwens, Rychard, Bradley, Larry, Broadhurst, Tom, Cenko, Stephen Bradley, Donahue, Megan, Filippenko, Alexei V, Ford, Holland, Garnavich, Peter, Grillo, Claudio, Infante, Leopoldo, Jouvel, Stephanie, Kelson, Daniel, Koekemoer, Anton, Lahav, Ofer, Lemze, Doron, Maoz, Dan, Medezinski, Elinor, Melchior, Peter, Meneghetti, Massimo, Molino, Alberto, Moustakas, John, Moustakas, Leonidas A, Nonino, Mario, Rosati, Piero, Seitz, Stella, Strolger, Louis G, Umetsu, Keiichi, and Zheng, Wei

Subjects
Astronomy, Astrophysics
Abstract

We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was approx. 1.0 +/- 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is approx. 0.2 +/- 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log10 μ): 0.83 +/- 0.16 mag for SN CLO12Car, 0.28 +/- 0.08 mag for SN CLN12Did, and 0.43 +/- 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.

Published
2014
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2. HST-COS Observations on Hydrogen, Helium, Carbon, and Nitrogen Emission from the SN 1987A Reverse Shock

Author

France, Kevin, McCray, Richard, Penton, Steven V, Kirshner, Robert P, Challis, Peter, Laming, J. Martin, Bouchet, Patrice, Chevalier, Roger, Garnavich, Peter M, Fransson, Claes, Heng, Kevin, Larsson, Josefin, Lawrence, Stephen, Lundqvist, Peter, Panagia, Nino, Pun, Chun S. J, Smith, Nathan, Sollerman, Jesper, Sonneborn, George, Sugerman, Ben, and Wheeler, J. Craig

Subjects
Astronomy
Abstract

We present the most sensitive ultraviolet observations of Supernova 1987 A to date. Imaging spectroscopy from the Hubble Space Telescope-Cosmic Origins Spectrograph shows many narrow (Delta v approximates 300 km/s) emission lines from the circumstellar ring, broad Delta v approximates 10-20 x 10(exp 3) km/s) emission lines from the reverse shock, and ultraviolet continuum emission. The high signal-to-noise ratio (>40 per resolution element) broad Ly-alpha emission is excited by soft X-ray and EUV heating of mostly neutral gas in the circumstellar ring and outer supernova debris. The ultraviolet continuum at lambda > 1350 A can be explained by H-I two-photon (2s(exp 2)S(sub 1/2)-l(exp 2)S(sub 1/2)) emission from the same region. We confirm our earlier, tentative detection of N V lambda 1240 emission from the reverse shock and present the first detections of broad He II lambda1640, C IV lambda 1550, and N IV ] lambda1486 emission lines from the reverse shock. The helium abundance in the high-velocity material is He/H = 0.14 +/- 0.06. The N V /H alpha line ratio requires partial ion-electron equilibration (T(sub e)/T(sub p) approximately equal to 0.14-0.35). We find that the N/C abundance ratio in the gas crossing the reverse shock is significantly higher than that in the circumstellar ring, a result that may be attributed to chemical stratification in the outer envelope of the supernova progenitor. The N/C abundance may have been stratified prior to the ring expUlsion, or this result may indicate continued CNO processing in the progenitor subsequent to the expUlsion of the circumstellar ring.

Published
2011
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3. Observing Supernova 1987A with the Refurbished Hubble Space Telescope

Author

France, Kevin, McCray, Richard, Heng, Kevin, Kirshner, Robert P, Challis, Peter, Bouchet, Patrice, Crotts, Arlin, Dwek, Eli, Fransson, Claes, Garnavich, Peter M, Larsson, Josefin, Lundqvist, Peter, Panagia, Nino, Pun, Chun S. J, Smith, Nathan, Sollerman, Jesper, Sonneborn, George, Stocke, John T, and Wheeler, J. Craig

Subjects
Astronomy
Abstract

The young remnant of supernova 1987A (SN 1987A) offers an unprecedented glimpse into the hydrodynamics and kinetics of fast astrophysical shocks. We have been monitoring SN 1987A with the Hubble Space Telescope (HST) since it was launched. The recent repair of the Space Telescope Imaging Spectrograph (STIS) allows us to compare observations in 2004, just before its demise, with those in 2010, shortly after its resuscitation by NASA astronauts. We find that the Ly-alpha and H-alpha lines from shock emission continue to brighten, while their maximum velocities continue to decrease. We report evidence for nearly coherent, resonant scattering of Lya photons (to blueshifts approximately -12,000 km /s) from hotspots on the equatorial ring. We also report emission to the red of Ly-alpha that we attribute to N v lambda lambda 1239,1243 Angstrom line emission. These lines are detectable because, unlike hydrogen atoms, N4+ ions emit hundreds of photons before they are ionized. The profiles of the N v lines differ markedly from that of H-alpha. We attribute this to scattering of N4+ ions by magnetic fields in the ionized plasma. Thus, N v emission provides a unique probe of the isotropization zone of the collisionless shock. Observations with the recently installed Cosmic Origins Spectrograph (COS) will enable us to observe the N v lambda lambda 1239,1243 Angstrom line profiles with much higher signal-to-noise ratios than possible with STIS and may reveal lines of other highly ionized species (such as C IVlambda lambda 1548,1551 Angstrom) that will test our explanation for the N v emission

Published
2010

4. New Hubble Space Telescope Observations of High-Velocity Ly(alpha) and H(alpha) in SNR 1987A

Author

Michael, Eli, McCray, Richard, Pun, C. S. J, Borkowski, Kazimierz, Garnavich, Peter, Challis, Peter, Kirshner, Robert P, Chevalier, Roger, Filippenko, Alexei V, Fransson, Claes, Panagia, Nino, Phillips, Mark, Schmidt, Brian, and Suntzef, Nicholas

Subjects
Astronomy
Abstract

We describe and model high-velocity (approximately 15,000 km S(exp -1)) Ly Alpha and H Alpha emission from the supernova remnant SNR 1987A seen in 1997 September and October with the Space Telescope Imaging Spectrograph. Part of this emission comes from a reverse shock located at approximately 75% of the radius of the inner boundary ofthe innercircumstellar ring and confined within + or - 30 degrees of the equatorial plane. Departure from axisymmetry in the Ly Alpha and H Alpha emission correlates with that seen in nonthermal radio emission and reveals an asymmetry in the circumstellar gas distribution. We also see diffuse high-velocity Ly-Alpha emission from supernova debris inside the reverse shock that may be due to excitation by nonthermal particles accelerated by the shock.

Published
1998

5. Ginga and ROSAT observations of the cataclysmic variable S193

Author

Szkody, Paula, Garnavich, Peter, Castelaz, Michael, and Makino, F

Subjects
Astronomy
Abstract

The cataclysmic variable S193 was observed with the Ginga and ROSAT satellites, along with ground-based optical observations. The bremsstrahlung temperatures and the column densities derived from these two observations are noticeably different. However, since the observations were separated by 3 yr and took place at different optical magnitudes, it is not clear whether this is related to an intrinsic change in the system or to a two component source of X-rays. While the X-ray data are not sufficient to accomplish a detailed analysis for periodicities, the Ginga data place an upper limit of 40% on the amplitude of any sinusoidal modulation.

Published
1994
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8. THE EFFECT OF WEAK LENSING ON DISTANCE ESTIMATES FROM SUPERNOVAE.

Author

Smith, Mathew, Bacon, David J., Nichol, Robert C., Campbell, Heather, Clarkson, Chris, Maartens, Roy, D'Andrea, Chris B., Bassett, Bruce A., Cinabro, David, Finley, David A., Frieman, Joshua A., Galbany, Lluis, Garnavich, Peter M., Olmstead, Matthew D., Schneider, Donald P., Shapiro, Charles, and Sollerman, Jesper

Subjects
SUPERNOVAE, CATACLYSMIC variable stars, GALACTIC X-ray sources, GALAXIES, ASTRONOMY
Abstract

Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight. We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction from lensing (at a significance of 1.7σ). Strong correlations are also found between the residuals and supernova nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the lensing signal is detected at 1.4σ. We show, for the first time, that distance estimates from supernovae can be improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic microwave background data from WMAP7, H0 data from Hubble Space Telescope and Sloan Digital Sky Survey (SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and show that the central values and uncertainties on Ωm and w are unaffected. The lensing of supernovae, while only seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of surveys, such as DES and LSST, which will be systematics-dominated. [ABSTRACT FROM AUTHOR]

Published
2014
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9. THE MID-INFRARED AND OPTICAL DECAY OF SN 2011fe.

Author

MCCLELLAND, COLIN M., GARNAVICH, PETER M., MILNE, PETER A., SHAPPEE, BENJAMIN J., and POGGE, RICHARD W.

Subjects
*STARS, *NEBULAE, *GALAXIES, *ASTRONOMY, *PHYSICS
Abstract

We measure the decay rate of the mid-IR luminosity from Type Ia supernova 2011fe between six months and one year after explosion using Spitzer/IRAC observations. The fading in the 3.6μm channel is 1.48±0.02 mag/100d, which is similar to that seen in blue optical bands. The supernova brightness fades at 0.78 ± 0.02 mag/100d in the 4.5μm channel which is close to that observed in the near-IR. We argue that the difference is a result of doubly ionized iron-peak elements dominating the bluer IRAC band while singly ionized species are controlling the longer wavelength channel. To test this, we use Large Binocular Telescope spectra taken during the same phases to show that doubly ionized emission lines do fade more slowly than their singly ionized cousins. We also find that [Co iii] emission fades at more than twice the radioactive decay rate due to the combination of decreasing excitation in the nebula, recombination and cobalt decaying to iron. The nebular emission velocities of [Fe iii] and [Co iii] lines show a smaller blueshift than emission from singly ionized atoms. The Si ii velocity gradient near maximum light combined with our nebular velocity measurements suggest SN 2011fe was a typical member of the "low velocity gradient" class of Type Ia. Analyzing IRAC photometry from other supernovae we find that mid-IR color of Type Ia events is correlated with the early light curve width and can be used as an indicator of the radioactive nickel yield. [ABSTRACT FROM AUTHOR]

Published
2013
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10. A TYPE Ia SUPERNOVA AT REDSHIFT 1.55 IN HUBBLE SPACE TELESCOPE INFRARED OBSERVATIONS FROM CANDELS.

Author

Rodney, Steven A., Riess, Adam G., Dahlen, Tomas, Strolger, Louis-Gregory, Ferguson, Henry C., Hjorth, Jens, Frederiksen, Teddy F., Weiner, Benjamin J., Mobasher, Bahram, Casertano, Stefano, Jones, David O., Challis, Peter, Faber, S. M., Filippenko, Alexei V., Garnavich, Peter, Graur, Or, Grogin, Norman A., Hayden, Brian, Jha, Saurabh W., and Kirshner, Robert P.

Subjects
TYPE I supernovae, REDSHIFT, ASTRONOMICAL spectroscopy, ASTRONOMY
Abstract

We report the discovery of a Type la supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SN Ia with direct spectroscopic evidence for classification. It is also the first SN Ia at z > 1 found and followed in the infrared, providing a full light curve in rest-frame optical bands. The classification and redshift are securely defined from a combination of multi-band and multi-epoch photometry of the SN, ground-based spectroscopy of the host galaxy, and WFC3-IR grism spectroscopy of both the SN and host. This object is the first of a projected sample at z > 1.5 that will be discovered by the CANDELS and CLASH programs. The full CANDELS+CLASH SN Ia sample will enable unique tests for evolutionary effects that could arise due to differences in SN Ia progenitor systems as a function of redshift. This high-z sample will also allow measurement of the SN Ia rate out to z ≈ 2, providing a complementary constraint on SN Ia progenitor models. [ABSTRACT FROM AUTHOR]

Published
2012
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11. LSST Science Book, Version 2.0

Author

Lsst, Science Collaboration, Abell, Paul A., Allison, Julius, Anderson, Scott F., Andrew, John R., Angel, J. Roger P., Armus, Lee, Arnett, David, Asztalos, S. J., Axelrod, Tim S., Bailey, Stephen, Ballantyne, D. R., Bankert, Justin R., Barkhouse, Wayne A., Barr, Jeffrey D., Barrientos, L. Felipe, Barth, Aaron J., Bartlett, James G., Becker, Andrew C., Becla, Jacek, Beers, Timothy C., Bernstein, Joseph P., Biswas, Rahul, Blanton, Michael R., Bloom, Joshua S., Bochanski, John J., Boeshaar, Pat, Borne, Kirk D., Bradac, Marusa, Brandt, W. N., Bridge, Carrie R., Brown, Michael E., Brunner, Robert J., Bullock, James S., Burgasser, Adam J., Burge, James H., Burke, David L., Cargile, Phillip A., Chandrasekharan, Srinivasan, Chartas, George, Chesley, Steven R., Chu, You-Hua, Cinabro, David, Claire, Mark W., Claver, Charles F., Clowe, Douglas, Connolly, A. J., Cook, Kem H., Cooke, Jeff, Cooray, Asantha, Covey, Kevin R., Culliton, Christopher S., Jong, Roelof, Vries, Willem H., Debattista, Victor P., Delgado, Francisco, Antonio, Ian P., Dhital, Saurav, Di Stefano, Rosanne, Dickinson, Mark, Dilday, Benjamin, Djorgovski, S. G., Dobler, Gregory, Donalek, Ciro, Dubois-Felsmann, Gregory, Durech, Josef, Eliasdottir, Ardis, Eracleous, Michael, Eyer, Laurent, Falco, Emilio E., Fan, Xiaohui, Fassnacht, Christopher D., Ferguson, Harry C., Fernandez, Yanga R., Fields, Brian D., Finkbeiner, Douglas, Figueroa, Eduardo E., Fox, Derek B., Francke, Harold, Frank, James S., Frieman, Josh, Fromenteau, Sebastien, Furqan, Muhammad, Galaz, Gaspar, Gal-Yam, A., Garnavich, Peter, Gawiser, Eric, Geary, John, Gee, Perry, Gibson, Robert R., Gilmore, Kirk, Grace, Emily A., Green, Richard F., Gressler, William J., Grillmair, Carl J., Habib, Salman, Haggerty, J. S., Hamuy, Mario, Harris, Alan W., Hawley, Suzanne L., Heavens, Alan F., Hebb, Leslie, Henry, Todd J., Hileman, Edward, Hilton, Eric J., Hoadley, Keri, Holberg, J. B., Holman, Matt J., Howell, Steve B., Infante, Leopoldo, Ivezic, Zeljko, Jacoby, Suzanne H., Jain, Bhuvnesh, R, Jedicke, Jee, M. James, Garrett Jernigan, J., Jha, Saurabh W., Johnston, Kathryn V., Jones, R. Lynne, Juric, Mario, Kaasalainen, Mikko, Styliani, Kafka, Kahn, Steven M., Kaib, Nathan A., Kalirai, Jason, Kantor, Jeff, Kasliwal, Mansi M., Keeton, Charles R., Kessler, Richard, Knezevic, Zoran, Kowalski, Adam, Krabbendam, Victor L., Krughoff, K. Simon, Kulkarni, Shrinivas, Kuhlman, Stephen, Lacy, Mark, Lepine, Sebastien, Liang, Ming, Lien, Amy, Lira, Paulina, Long, Knox S., Lorenz, Suzanne, Lotz, Jennifer M., Lupton, R. H., Lutz, Julie, Macri, Lucas M., Mahabal, Ashish A., Mandelbaum, Rachel, Marshall, Phil, May, Morgan, Mcgehee, Peregrine M., Meadows, Brian T., Meert, Alan, Milani, Andrea, Miller, Christopher J., Miller, Michelle, Mills, David, Minniti, Dante, Monet, David, Mukadam, Anjum S., Nakar, Ehud, Neill, Douglas R., Newman, Jeffrey A., Nikolaev, Sergei, Nordby, Martin, O Connor, Paul, Oguri, Masamune, Oliver, John, Olivier, Scot S., Olsen, Julia K., Olsen, Knut, Olszewski, Edward W., Oluseyi, Hakeem, Padilla, Nelson D., Parker, Alex, Pepper, Joshua, Peterson, John R., Petry, Catherine, Pinto, Philip A., Pizagno, James L., Popescu, Bogdan, Prsa, Andrej, Radcka, Veljko, Raddick, M. Jordan, Rasmussen, Andrew, Rau, Arne, Rho, Jeonghee, Rhoads, James E., Richards, Gordon T., Ridgway, Stephen T., Robertson, Brant E., Roskar, Rok, Saha, Abhijit, Sarajedini, Ata, Scannapieco, Evan, Schalk, Terry, Schindler, Rafe, Schmidt, Samuel, Schmidt, Sarah, Schneider, Donald P., Schumacher, German, Scranton, Ryan, Sebag, Jacques, Seppala, Lynn G., Ohad Shemmer, Simon, Joshua D., Sivertz, M., Smith, Howard A., Allyn Smith, J., Smith, Nathan, Spitz, Anna H., Stanford, Adam, Stassun, Keivan G., Strader, Jay, Strauss, Michael A., Stubbs, Christopher W., Sweeney, Donald W., Szalay, Alex, Szkody, Paula, Takada, Masahiro, Thorman, Paul, Trilling, David E., Trimble, Virginia, Tyson, Anthony, Berg, Richard, Vanden Berk, Daniel, Vanderplas, Jake, Verde, Licia, Vrsnak, Bojan, Walkowicz, Lucianne M., Wandelt, Benjamin D., Wang, Sheng, Wang, Yun, Warner, Michael, Wechsler, Risa H., West, Andrew A., Wiecha, Oliver, Williams, Benjamin F., Willman, Beth, Wittman, David, Wolff, Sidney C., Wood-Vasey, W. Michael, Wozniak, Przemek, Young, Patrick, Zentner, Andrew, Zhan, Hu, APC - Cosmologie, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), LSST, Bartlett, James, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], media_common.quotation_subject, Milky Way, FOS: Physical sciences, Large Synoptic Survey Telescope, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Weak gravitational lensing, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, media_common, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR.CO] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Redshift, Galaxy, Astrophysics - Solar and Stellar Astrophysics, Sky, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics of Galaxies (astro-ph.GA), Dark energy, Instrumentation and Methods for Astrophysics, Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy., 596 pages. Also available at full resolution at http://www.lsst.org/lsst/scibook

12. Physics in the extreme: X-ray and optical studies of magnetic white dwarfs and related objects

Author

Kennedy, Mark R., Callanan, Paul, and Garnavich, Peter

Subjects
Cataclysmic variables, Accretion, Interacting binary stars, Astronomy, Physics
Abstract

In this thesis, we present results from optical and X-ray studies of compact binary systems. These observations are used to constrain orbital parameters - mainly periods and inclinations for several cataclysmic variables - and examine the accretion structures within the systems. In Chapters 3 and 4, optical and X-ray studies of two interesting cataclysmic variables systems, Lanning 386 and MASTER OTJ192328.22+612413.5, are presented. The X-ray and optical data of these objects suggest that both systems have a high inclination and harbour weakly magnetic white dwarfs with spin periods 17-22 min. There is also a strong focus on studying the long term behaviour in intermediate polars in this thesis. Chapter 5 presents results from Kepler observations of FO Aquarii taken over 69 consecutive days. The shape of the light curve is consistent with the outer edge of the accretion disc being eclipsed and the detected period is longer than the last reported period of 1254.284(16) s, suggesting that FO Aqr was now spinning down, and had a positive P˙ at the time of the observations. Chapter 6 continues the work on FO Aquarii, and presents X-ray data taken during a low accretion state. The X-ray spectrum shows an increase in the ratio of the soft X-ray flux to the hard X-ray flux due to a change in the partial covering fraction of the white dwarf and a change in the hydrogen column density within the disc. XMM-Newton observations of FO Aqr during the subsequent recovery suggest that the system had not yet returned to its typical high state by November 2016. The spin period of the white dwarf in 2014 and 2015 is refined to 1254.3342(8) s. Chapter 7 focuses on CSS120422:J111127+571239, an “evolved main-sequence” channel cataclysmic variable. We present spectroscopy of CSS120422:J111127+571239 using the COS FUV instrument on the Hubble Space Telescope and using the MODS spectrograph on the Large Binocular Telescope. The UV spectrum shows Si IV, N V and He II, but no detectable C IV. The anomalous nitrogen/carbon ratio is seen in a small number of other CVs and confirms a unique binary evolution. We also present and compare the optical spectrum of V418 Ser and advocate that it is also an evolved main-sequence system. Finally, Chapter 8 presents results on UW Coronae Borealis, a low mass X-ray x Abstract binary that shows both Type 1 X-ray and optical bursts. The orbital period is refined to 110.97680(1) min. 17 optical bursts are presented, with 10 of these bursts being resolved temporally. The average e-folding time of 19 ± 3s for the bursts is consistent with the previously found value. Optical bursts are observed during a previously identified gap in orbital phase centred on φ = 0.967, meaning the reprocessing site is not eclipsed as previously thought. Finally, the apparent P-Cygni profiles present in some of the atomic lines in the optical spectra are due to transient absorption, which suggests the origin of the absorption is not a wind from the primary.

Published
2017

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