135 research outputs found

    Low energy cluster beam deposited BN films as the cascade for Field Emission

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    The atomic deposited BN films with the thickness of nanometers (ABN) were prepared by radio frequency magnetron sputtering method and the nanostructured BN films (CBN) were prepared by Low Energy Cluster Beam Deposition. UV-Vis Absorption measurement proves the band gap of 4.27eV and field emission of the BN films were carried out. F-N plots of all the samples give a good fitting and demonstrate the F-N tunneling of the emission process. The emission of ABN begins at the electric field of 14.6 V/{\mu}m while that of CBN starts at 5.10V/{\mu}m. Emission current density of 1mA/cm2 for ABN needs the field of 20V/{\mu}m while that of CBN needs only 12.1V/{\mu}m. The cluster-deposited BN on n-type Silicon substrate proves a good performance in terms of the lower gauge voltage, more emission sites and higher electron intensity and seems a promising substitute for the cascade of Field Emission

    Statistics of leading digits leads to unification of quantum correlations

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    We show that the frequency distribution of the first significant digits of the numbers in the data sets generated from a large class of measures of quantum correlations, which are either entanglement measures, or belong to the information-theoretic paradigm, exhibit a universal behaviour. In particular, for Haar uniformly simulated arbitrary two-qubit states, we find that the first-digit distribution corresponding to a collection of chosen computable quantum correlation quantifiers tend to follow the first-digit law, known as the Benford's law, when the rank of the states increases. Considering a two-qubit state which is obtained from a system governed by paradigmatic spin Hamiltonians, namely, the XY model in a transverse field, and the XXZ model, we show that entanglement as well as information theoretic measures violate the Benford's law. We quantitatively discuss the violation of the Benford's law by using a violation parameter, and demonstrate that the violation parameter can signal quantum phase transitions occurring in these models. We also comment on the universality of the statistics of first significant digits corresponding to appropriate measures of quantum correlations in the case of multipartite systems as well as systems in higher dimensions.Comment: v1: 11 pages, 5 figures, 2 tables; v2: 11 pages, 6 figures, 2 tables, new results added, extended version of the published pape

    The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae

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    The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.Comment: Updated a couple of small error

    The Carnegie Supernova Project. I. Third Photometry Data Release of Low-redshift Type Ia Supernovae and Other White Dwarf Explosions

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    We present final natural-system optical (ugriBV) and near-infrared (YJH) photometry of 134 supernovae (SNe) with probable white dwarf progenitors that were observed in 2004-2009 as part of the first stage of the Carnegie Supernova Project (CSP-I). The sample consists of 123 Type Ia SNe, 5 Type Iax SNe, 2 super-Chandrasekhar SN candidates, 2 Type Ia SNe interacting with circumstellar matter, and 2 SN 2006bt-like events. The redshifts of the objects range from to 0.0835; the median redshift is 0.0241. For 120 (90%) of these SNe, near-infrared photometry was obtained. Average optical extinction coefficients and color terms are derived and demonstrated to be stable during the five CSP-I observing campaigns. Measurements of the CSP-I near-infrared bandpasses are also described, and near-infrared color terms are estimated through synthetic photometry of stellar atmosphere models. Optical and near-infrared magnitudes of local sequences of tertiary standard stars for each supernova are given, and a new calibration of Y-band magnitudes of the Persson et al. standards in the CSP-I natural system is presented.Fil: Krisciunas, Kevin. Texas A&M University; Estados UnidosFil: Contreras, Carlos. University Aarhus; Dinamarca. Las Campanas Observatory; ChileFil: Burns, Christopher R.. Las Campanas Observatory; ChileFil: Phillips, M. M.. Las Campanas Observatory; ChileFil: Stritzinger, Maximilian D.. Las Campanas Observatory; Chile. University Aarhus; DinamarcaFil: Morrell, Nidia Irene. Las Campanas Observatory; ChileFil: Hamuy, Mario. Universidad de Chile; ChileFil: Anais, Jorge. Las Campanas Observatory; ChileFil: Boldt, Luis. Las Campanas Observatory; ChileFil: Busta, Luis. Las Campanas Observatory; ChileFil: Campillay, Abdo. Las Campanas Observatory; ChileFil: Castellón, Sergio. Las Campanas Observatory; ChileFil: Folatelli, Gaston. Las Campanas Observatory; Chile. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Freedman, Wendy L.. University of Chicago; Estados UnidosFil: González, Consuelo. Las Campanas Observatory; ChileFil: Hsiao, Eric Y.. Florida State University; Estados Unidos. University Aarhus; Dinamarca. Las Campanas Observatory; ChileFil: Krzeminski, Wojtek. Las Campanas Observatory; ChileFil: Persson, Sven Eric. Carnegie Observatories;Fil: Roth, Miguel. Gmto Corporation; Chile. Las Campanas Observatory; ChileFil: Salgado, Francisco. Leiden Observatory Research Institute; . Las Campanas Observatory; ChileFil: Serón, Jacqueline. Las Campanas Observatory; Chile. Cerro Tololo Inter American Observatory; ChileFil: Suntzeff, Nicholas B.. Texas A&M University; Estados UnidosFil: Torres, Simón. Soar Telescope; Chile. Las Campanas Observatory; ChileFil: Filippenko, Alexei V.. University of California at Berkeley; Estados UnidosFil: Li, Weidong. University of California at Berkeley; Estados UnidosFil: Madore, Barry F.. Jet Propulsion Laboratory, California Institute Of Technology; . Las Campanas Observatory; ChileFil: DePoy, D.L.. Texas A&M University; Estados UnidosFil: Marshall, Jennifer L.. Texas A&M University; Estados UnidosFil: Rheault, Jean Philippe. Texas A&M University; Estados UnidosFil: Villanueva, Steven. Texas A&M University; Estados Unidos. Ohio State University; Estados Unido

    The Carnegie Supernova Project II. The shock wave revealed through the fog: The strongly interacting Type IIn SN 2013L

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    We present ultra-violet to mid-infrared observations of the long-lasting Type IIn supernova (SN) 2013L obtained by the Carnegie Supernova Project II (CSP-II). The spectra of SN 2013L are dominated by H emission features characterized by three components attributed to different regions. A unique feature of this Type IIn SN is that the blue shifted line profile is dominated by the macroscopic velocity of the expanding shock wave of the SN. We are therefore able to trace the evolution of the shock velocity in the dense and partially opaque circumstellar medium (CSM), from 4800 km s1\sim 4800~km~s^{-1} at +48 d, decreasing as t0.23t^{-0.23} to 2700 km s1\sim 2700~km~s^{-1} after a year. We perform spectral modeling of both the broad- and intermediate-velocity components of the Hα\alpha line profile. The high-velocity component is consistent with emission from a radially thin, spherical shell located behind the expanding shock with emission wings broadened by electron scattering. We propose that the intermediate component originates from pre-ionized gas from the unshocked dense CSM with the same velocity as the narrow component, 100 km s1\sim 100~km~s^{-1}, but also broadened by electron scattering. The spectral energy distributions (SEDs) of SN 2013L after +132 d are well reproduced by a two-component black-body (BB) model. The circumstellar-interaction model of the bolometric light curve reveals a mass-loss rate history with large values (1.7×1020.15 M yr11.7\times 10^{-2} - 0.15~M_\odot~yr^{-1}) over the \sim 25 - 40 years before explosion. The drop in the light curve at 350\sim 350 days and presence of electron scattering wings at late epochs indicate an anisotropic CSM. The mass-loss rate values and the unshocked CSM velocity are consistent with the characteristics of a massive star, such as a luminous blue variable (LBV) undergoing strong eruptions, similar to η\eta Carina.Comment: Replaced after language editor corrections, accepted for publication on Astronomy and Astrophysics, 43 pages, 29 figures. Abstract abridge

    Carnegie Supernova Project-II: Extending the Near-Infrared Hubble Diagram for Type Ia Supernovae to z0.1z\sim0.1

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    The Carnegie Supernova Project-II (CSP-II) was an NSF-funded, four-year program to obtain optical and near-infrared observations of a "Cosmology" sample of 100\sim100 Type Ia supernovae located in the smooth Hubble flow (0.03z0.100.03 \lesssim z \lesssim 0.10). Light curves were also obtained of a "Physics" sample composed of 90 nearby Type Ia supernovae at z0.04z \leq 0.04 selected for near-infrared spectroscopic time-series observations. The primary emphasis of the CSP-II is to use the combination of optical and near-infrared photometry to achieve a distance precision of better than 5%. In this paper, details of the supernova sample, the observational strategy, and the characteristics of the photometric data are provided. In a companion paper, the near-infrared spectroscopy component of the project is presented.Comment: 43 pages, 10 figures, accepted for publication in PAS

    Carnegie Supernova Project: The First Homogeneous Sample of Super-Chandrasekhar-mass/2003fg-like Type Ia Supernovae

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    We present a multiwavelength photometric and spectroscopic analysis of 13 super-Chandrasekhar-mass/2003fg-like Type Ia supernovae (SNe Ia). Nine of these objects were observed by the Carnegie Supernova Project. The 2003fg-like SNe have slowly declining light curves (Δm 15(B) < 1.3 mag), and peak absolute B-band magnitudes of -19 < M B < -21 mag. Many of the 2003fg-like SNe are located in the same part of the luminosity-width relation as normal SNe Ia. In the optical B and V bands, the 2003fg-like SNe look like normal SNe Ia, but at redder wavelengths they diverge. Unlike other luminous SNe Ia, the 2003fg-like SNe generally have only one i-band maximum, which peaks after the epoch of the B-band maximum, while their near-IR (NIR) light-curve rise times can be ⪆40 days longer than those of normal SNe Ia. They are also at least 1 mag brighter in the NIR bands than normal SNe Ia, peaking above M H = -19 mag, and generally have negative Hubble residuals, which may be the cause of some systematics in dark-energy experiments. Spectroscopically, the 2003fg-like SNe exhibit peculiarities such as unburnt carbon well past maximum light, a large spread (8000-12,000 km s-1) in Si ii λ6355 velocities at maximum light with no rapid early velocity decline, and no clear H-band break at +10 days. We find that SNe with a larger pseudo-equivalent width of C ii at maximum light have lower Si ii λ6355 velocities and more slowly declining light curves. There are also multiple factors that contribute to the peak luminosity of 2003fg-like SNe. The explosion of a C-O degenerate core inside a carbon-rich envelope is consistent with these observations. Such a configuration may come from the core-degenerate scenario.Fil: Ashall, C.. University Hawaii Institute For Astronomy; Estados UnidosFil: Lu, J.. Florida State University; Estados UnidosFil: Hsiao, E. Y.. Florida State University; Estados UnidosFil: Hoeflich, P.. Florida State University; Estados UnidosFil: Phillips, M. M.. Las Campanas Observatory; ChileFil: Galbany, Lluís. Instituto de Ciencias del Espacio; EspañaFil: Burns, C. R.. Las Campanas Observatory; ChileFil: Contreras, C.. Las Campanas Observatory; ChileFil: Krisciunas, K.. Texas A&M University; Estados UnidosFil: Morrell, Nidia Irene. Las Campanas Observatory; ChileFil: Stritzinger, M. D.. University Aarhus; DinamarcaFil: Suntzeff, Nicholas B.. Texas A&M University; Estados UnidosFil: Taddia, F.. University Aarhus; DinamarcaFil: Anais, J.. Las Campanas Observatory; ChileFil: Baron, E.. Oklahoma State University; Estados Unidos. Universitat Hamburg; AlemaniaFil: Brown, P. J.. Texas A&M University; Estados UnidosFil: Busta, L.. Las Campanas Observatory; ChileFil: Campillay, A.. Universidad de La Serena; ChileFil: Castellón, S.. Las Campanas Observatory; ChileFil: Corco, C.. Las Campanas Observatory; Chile. Soar Telescope; ChileFil: Davis, S.. University of California at Davis; Estados UnidosFil: Folatelli, Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Förster, F.. Universidad de Chile; Chile. Instituto Milenio de Astrofísica; ChileFil: Freedman, W. L.. University of Chicago; Estados UnidosFil: Gonzaléz, C.. Las Campanas Observatory; ChileFil: Hamuy, M.. Universidad de Chile; ChileFil: Holmbo, S.. University Aarhus; DinamarcaFil: Kirshner, R. P.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Kumar, S.. Florida State University; Estados UnidosFil: Marion, G. H.. University of Texas at Austin; Estados UnidosFil: Mazzali, P.. Liverpool John Moores University; Reino UnidoFil: Morokuma, T.. The University Of Tokyo; JapónFil: Nugent, P. E.. Lawrence Berkeley National Laboratory; Estados Unidos. University of California at Berkeley; Estados UnidosFil: Persson, S. E.. Las Campanas Observatory; ChileFil: Piro, A. L.. Las Campanas Observatory; ChileFil: Roth, M.. Las Campanas Observatory; ChileFil: Salgado, F.. Las Campanas Observatory; ChileFil: Sand, D.J.. University of Arizona; Estados UnidosFil: Seron, J.. Las Campanas Observatory; ChileFil: Shahbandeh, M.. Florida State University; Estados UnidosFil: Shappee, B. J.. University Hawaii Institute For Astronomy; Estados Unido

    ASASSN-15hy: An Underluminous, Red 03fg-like Type Ia Supernova

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    We present photometric and spectroscopic observations of the 03fg-like Type Ia supernova (SN Ia) ASASSN-15hy from the ultraviolet (UV) to the near-infrared (NIR). ASASSN-15hy shares many of the hallmark characteristics of 03fg-like SNe Ia, previously referred to as "super-Chandrasekhar" SNe Ia. It is bright in the UV and NIR, lacks a clear i-band secondary maximum, shows a strong and persistent C ii feature, and has a low Si ii lambda 6355 velocity. However, some of its properties are also extreme among the subgroup. ASASSN-15hy is underluminous (M (B,peak) = -19.14(-0.16)(+0.11) mag), red ((B-V)(Bmax)= 0.18(-0.03)(+0.01) mag), yet slowly declining (Delta m (15)(B) = 0.72 +/- 0.04 mag). It has the most delayed onset of the i-band maximum of any 03fg-like SN. ASASSN-15hy lacks the prominent H-band break emission feature that is typically present during the first month past maximum in normal SNe Ia. Such events may be a potential problem for high-redshift SN Ia cosmology. ASASSN-15hy may be explained in the context of an explosion of a degenerate core inside a nondegenerate envelope. The explosion impacting the nondegenerate envelope with a large mass provides additional luminosity and low ejecta velocities. An initial deflagration burning phase is critical in reproducing the low Ni-56 mass and luminosity, while the large core mass is essential in providing the large diffusion timescales required to produce the broad light curves. The model consists of a rapidly rotating 1.47 M-circle dot degenerate core and a 0.8 M-circle dot nondegenerate envelope. This "deflagration core-degenerate" scenario may result from the merger between a white dwarf and the degenerate core of an asymptotic giant branch star

    Optical Spectroscopy of Type Ia Supernovae by the Carnegie Supernova Projects I and II

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    We present the second and final release of optical spectroscopy of Type Ia supernovae (SNe Ia) obtained during the first and second phases of the Carnegie Supernova Project (CSP-I and CSP-II). The newly released data consist of 148 spectra of 30 SNe Ia observed in the course of CSP-I and 234 spectra of 127 SNe Ia obtained during CSP-II. We also present 216 optical spectra of 46 historical SNe Ia, including 53 spectra of 30 SNe Ia observed by the Calán/Tololo Supernova Survey. We combine these observations with previously published CSP data and publicly available spectra to compile a large sample of measurements of spectroscopic parameters at maximum light, consisting of pseudo-equivalent widths and expansion velocities of selected features for 232 CSP and historical SNe Ia (including more than 1000 spectra). Finally, we review some of the strongest correlations between spectroscopic and photometric properties of SNe Ia. Specifically, we define two samples: one consisting of SNe Ia discovered by targeted searches (most of them CSP-I objects) and the other composed of SNe Ia discovered by untargeted searches, which includes most of the CSP-II objects. The analyzed correlations are similar for both samples. We find a larger incidence of SNe Ia belonging to the cool and broad-line Branch subtypes among the events discovered by targeted searches, shallow-silicon SNe Ia are present with similar frequencies in both samples, while core normal SNe Ia are more frequent in untargeted searches
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