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Sample records for classical nova outburst

  1. The classical nova outburst

    International Nuclear Information System (INIS)

    The classical nova outburst occurs on the white dwarf component in a close binary system. Nova systems are members of the general class of cataclysmic variables and other members of the class are the Dwarf Novae, AM Her variables, Intermediate Polars, Recurrent Novae, and some of the Symbiotic variables. Although multiwavelength observations have already provided important information about all of these systems, in this review I will concentrate on the outbursts of the classical and recurrent novae and refer to other members of the class only when necessary. 140 refs., 1 tab

  2. The Outbursts of Classical and Recurrent Novae

    CERN Document Server

    Bode, M F

    2009-01-01

    In this review, I present our current state of knowledge regarding both Classical Nova and Recurrent Nova systems. Two particular objects (V1974 Cyg and RS Oph) are chosen to illustrate the range of phenomena that may be associated with their outbursts. The wider importance of nova research is emphasised and some of the most pressing unsolved problems are summarised.

  3. Observations of classical novae in outburst

    International Nuclear Information System (INIS)

    Over the past 10 years the IUE Satellite has obtained ultraviolet data on a number of novae in outburst and the characteristics of every one of the outbursts have been different. In addition, our group has also obtained optical and infrared data on many of the same novae. In this paper we present the data on three members of the carbon-oxygen class of novae

  4. The Thermonuclear Runaway and the Classical Nova Outburst

    CERN Document Server

    Starrfield, S; Hix, W R

    2016-01-01

    Nova explosions occur on the white dwarf component of a Cataclysmic Variable binary stellar system that is accreting matter lost by its companion. When sufficient material has been accreted by the white dwarf, a thermonuclear runaway occurs and ejects material in what is observed as a Classical Nova explosion. We describe both the recent advances in our understanding of the progress of the outburst and outline some of the puzzles that are still outstanding. We report on the effects of improving both the nuclear reaction rate library and including a modern nuclear reaction network in our one-dimensional, fully implicit, hydrodynamic computer code. In addition, there has been progress in observational studies of Supernovae Ia with implications about the progenitors and we discuss that in this review.

  5. The Thermonuclear Runaway and the Classical Nova Outburst

    Science.gov (United States)

    Starrfield, S.; Iliadis, C.; Hix, W. R.

    2016-05-01

    Nova explosions occur on the white dwarf component of a cataclysmic variable binary stellar system that is accreting matter lost by its companion. When sufficient material has been accreted by the white dwarf, a thermonuclear runaway occurs and ejects material in what is observed as a classical nova explosion. We describe both the recent advances in our understanding of the progress of the outburst and outline some of the puzzles that are still outstanding. We report on the effects of improving both the nuclear reaction rate library and including a modern nuclear reaction network in our one-dimensional, fully implicit, hydrodynamic computer code. In addition, there has been progress in observational studies of supernovae Ia with implications about the progenitors, and we discuss that in this review.

  6. Soft x-ray emission from classical novae in outburst

    International Nuclear Information System (INIS)

    Theoretical modeling of novae in outburst predicts that they should be active emitters of radiation at soft x-ray wavelengths twice during their outburst. The first time occurs very early in the outburst when only a very sensitive all sky survey will be able to detect them. This period lasts only a few hours for the very fastest novae. They again become bright in x-rays late in the outburst when the remnant object becomes very hot and is still luminous. Both simulations and observations show that novae can remain very hot for months to years. It is important to observe them at these late times because a measurement both of the flux and temperature can provide information about the mass of the white dwarf, the turn-off time scale, and the energy budget of the outburst. 8 refs., 2 figs

  7. Swift observations of the 2015 outburst of AG Peg -- from slow nova to classical symbiotic outburst

    CERN Document Server

    Ramsay, Gavin; Luna, G J M; Nunez, N E

    2016-01-01

    Symbiotic stars often contain white dwarfs with quasi-steady shell burning on their surfaces. However, in most symbiotics, the origin of this burning is unclear. In symbiotic slow novae, however, it is linked to a past thermonuclear runaway. In June 2015, the symbiotic slow nova AG Peg was seen in only its second optical outburst since 1850. This recent outburst was of much shorter duration and lower amplitude than the earlier eruption, and it contained multiple peaks -- like outbursts in classical symbiotic stars such as Z And. We report Swift X-ray and UV observations of AG Peg made between June 2015 and January 2016. The X-ray flux was markedly variable on a time scale of days, particularly during four days near optical maximum, when the X-rays became bright and soft. This strong X-ray variability continued for another month, after which the X-rays hardened as the optical flux declined. The UV flux was high throughout the outburst, consistent with quasi-steady shell burning on the white dwarf. Given that a...

  8. The time-dependent rebrightenings in classical novae outbursts: a late-time episodic fuel burning?

    OpenAIRE

    Pejcha, Ondrej

    2009-01-01

    A significant fraction of novae exhibit a series of rebrightenings on the decline branch of their light curves. We use visual observations to study this phase in several well-observed novae. We find that these rebrightenings are isolated flare-like events on otherwise smooth light curves and we show that in most novae in our sample the time intervals between consecutive flares gradually increase as a geometric series; rebrightenings are equally spaced in logarithmic time. We also find a corre...

  9. TIME-DEPENDENT REBRIGHTENINGS IN CLASSICAL NOVA OUTBURSTS: A LATE-TIME EPISODIC FUEL BURNING?

    International Nuclear Information System (INIS)

    A significant fraction of novae exhibit a series of rebrightenings on the decline branch of their light curves. We use visual observations to study this phase in several well-observed novae. We find that these rebrightenings are isolated flare-like events on otherwise smooth light curves and we show that in most novae in our sample the time intervals between consecutive flares gradually increase as a geometric series; rebrightenings are equally spaced in logarithmic time. We also find a correlation between the rate of increase in the time between rebrightenings with the speed class of the nova in the sense that slower novae tend to increase the time intervals faster. We attribute these rebrightenings to instabilities in the envelope hydrogen burning and we mention other cases of such timing patterns in astronomy and natural sciences in general.

  10. Nuclear Thermometers for Classical Novae

    CERN Document Server

    Downen, Lori N; José, Jordi; Starrfield, Sumner

    2012-01-01

    Classical novae are stellar explosions occurring in binary systems, consisting of a white dwarf and a main sequence companion. Thermonuclear runaways on the surface of massive white dwarfs, consisting of oxygen and neon, are believed to reach peak temperatures of several hundred million kelvin. These temperatures are strongly correlated with the underlying white dwarf mass. The observational counterparts of such models are likely associated with outbursts that show strong spectral lines of neon in their shells (neon novae). The goals of this work are to investigate how useful elemental abundances are for constraining the peak temperatures achieved during these outbursts and determine how robust "nova thermometers" are with respect to uncertain nuclear physics input. We present updated observed abundances in neon novae and perform a series of hydrodynamic simulations for several white dwarf masses. We find that the most useful thermometers, N/O, N/Al, O/S, S/Al, O/Na, Na/Al, O/P, and P/Al, are those with the s...

  11. AG Pegasi - now a classical symbiotic star in outburst?

    CERN Document Server

    Tomov, T V; Zamanov, R K

    2016-01-01

    Optical spectroscopy study of the recent AG Peg outburst observed during the second half of 2015 is presented. Considerable variations of the intensity and the shape of the spectral features as well as the changes of the hot component parameters, caused by the outburst, are discussed and certain similarities between the outburst of AG Peg and the outburst of a classical symbiotic stars are shown. It seems that after the end of the symbiotic nova phase, AG Peg became a member of the classical symbiotic stars group.

  12. NUCLEAR THERMOMETERS FOR CLASSICAL NOVAE

    International Nuclear Information System (INIS)

    Classical novae are stellar explosions occurring in binary systems, consisting of a white dwarf and a main-sequence companion. Thermonuclear runaways on the surface of massive white dwarfs, consisting of oxygen and neon, are believed to reach peak temperatures of several hundred million kelvin. These temperatures are strongly correlated with the underlying white dwarf mass. The observational counterparts of such models are likely associated with outbursts that show strong spectral lines of neon in their shells (neon novae). The goals of this work are to investigate how useful elemental abundances are for constraining the peak temperatures achieved during these outbursts and determine how robust 'nova thermometers' are with respect to uncertain nuclear physics input. We present updated observed abundances in neon novae and perform a series of hydrodynamic simulations for several white dwarf masses. We find that the most useful thermometers, N/O, N/Al, O/S, S/Al, O/Na, Na/Al, O/P, and P/Al, are those with the steepest monotonic dependence on peak temperature. The sensitivity of these thermometers to thermonuclear reaction rate variations is explored using post-processing nucleosynthesis simulations. The ratios N/O, N/Al, O/Na, and Na/Al are robust, meaning they are minimally affected by uncertain rates. However, their dependence on peak temperature is relatively weak. The ratios O/S, S/Al, O/P, and P/Al reveal strong dependences on temperature and the poorly known 30P(p, γ)31S rate. We compare our model predictions to neon nova observations and obtain the following estimates for the underlying white dwarf masses: 1.34-1.35 M ☉ (V838 Her), 1.18-1.21 M ☉ (V382 Vel), ≤1.3 M ☉ (V693 CrA), ≤1.2 M ☉ (LMC 1990 no. 1), and ≤1.2 M ☉ (QU Vul).

  13. Dwarf Nova Outbursts with Magnetorotational Turbulence

    CERN Document Server

    Coleman, M S B; Blaes, O; Lasota, J -P; Hirose, S

    2016-01-01

    The phenomenological Disc Instability Model has been successful in reproducing the observed light curves of dwarf nova outbursts by invoking an enhanced Shakura-Sunyaev $\\alpha$ parameter $\\sim0.1-0.2$ in outburst compared to a low value $\\sim0.01$ in quiescence. Recent thermodynamically consistent simulations of magnetorotational (MRI) turbulence with appropriate opacities and equation of state for dwarf nova accretion discs have found that thermal convection enhances $\\alpha$ in discs in outburst, but only near the hydrogen ionization transition. At higher temperatures, convection no longer exists and $\\alpha$ returns to the low value comparable to that in quiescence. In order to check whether this enhancement near the hydrogen ionization transition is sufficient to reproduce observed light curves, we incorporate this MRI-based variation in $\\alpha$ into the Disc Instability Model, as well as simulation-based models of turbulent dissipation and convective transport. These MRI-based models can successfully r...

  14. Statistical analysis of dwarf nova outbursts

    International Nuclear Information System (INIS)

    Correlation between maximum brightness, outburst width, lengths of preceding and following intervals has been studied for 14 dwarf novae (mostly from southern sky). Significant correlations (ρ ≥ 0.4) occur only in 16 per cent of cases, what confirms earlier results of Szkody and Mattei (1984). Global correlations have also been studied between mean photometric parameters and binary system parameters using a sample including over 30 objects. The most interesting result is the strong correlation (ρ = +0.94) between the orbital period and the outburst duration. It implies that the quantity α(z0/r)2 is approximately constant for all dwarf novae. Using typical estimates for z0/r we get α = 0.2. 30 refs., 1 figs., 2 tabs. (author)

  15. Statistical analysis of properties of dwarf novae outbursts

    CERN Document Server

    Otulakowska-Hypka, Magdalena; Patterson, Joseph

    2016-01-01

    We present a statistical study of all measurable photometric features of a large sample of dwarf novae during their outbursts and superoutbursts. We used all accessible photometric data for all our objects to make the study as complete and up-to-date as possible. Our aim was to check correlations between these photometric features in order to constrain theoretical models which try to explain the nature of dwarf novae outbursts. We managed to confirm a few of the known correlations, that is the Stolz and Schoembs Relation, the Bailey Relation for long outbursts above the period gap, the relations between the cycle and supercycle lengths, amplitudes of normal and superoutbursts, amplitude and duration of superoutbursts, outburst duration and orbital period, outburst duration and mass ratio for short and normal outbursts, as well as the relation between the rise and decline rates of superoutbursts. However, we question the existence of the Kukarkin-Parenago Relation but we found an analogous relation for superou...

  16. Quiescent and outburst photometry of the dwarf nova SS Cygni

    Energy Technology Data Exchange (ETDEWEB)

    Honey, W.B.; Bath, G.T.; Charles, P.A. and others

    1989-02-01

    It has been suggested that the wide outbursts of U Gem stars are analogous to the wide or 'super' outbursts of SU UMa stars and hence that the basic mechanism which gives rise to the two types of outburst is the same. If this is true, then the U Gem type stars should also exhibit some of the more exotic properties associated with superoutbursts in SU UMa stars, in particular superhumps. In order to test this hypothesis, extensive photometric observations of a wide and a narrow outburst (and also the period of quiescence separating them) of the dwarf nova SS Cygni were obtained in order to search for modulations at or near the orbital period. No such modulations were found in either the wide or narrow outbursts to a limit of /similar to/ 0.05 mag.

  17. A theoretical study of problems in classical nova evolution

    International Nuclear Information System (INIS)

    Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics. The effects of convection on nova outbursts are examined within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. The effects of a strong magnetic field on the TNR are explored. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately. The conditions necessary for the production of strong TNR's in the hibernation model of cataclysmic binary evolution are also examined. The feasibility of obtaining strong nova outbursts is investigated when the accretion rate during hibernation is decreased. It is found that a reduction (by a factor of 100) for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates. The effects of a common envelope phase (CEP) on the outburst are discussed. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km/sec

  18. Rebrightening Phenomenon in Classical Novae

    CERN Document Server

    Kato, Taichi; Maehara, Hiroyuki; Kiyota, Seiichiro

    2009-01-01

    Two classical novae V1493 Aql and V2362 Cyg were known to exhibit unprecedented large-amplitude rebrightening during the late stage of their evolution. We analyzed common properties in these two light curves. We show that these unusual light curves are very well expressed by a combination of power-law decline, omnipresent in fast novae, and exponential brightening. We propose a schematic interpretation of the properties common to these rebrightenings can be a consequence of a shock resulting from a secondary ejection and its breakout in the optically thick nova winds. This interpretation has an advantage in explaining the rapid fading following the rebrightening and the subsequent evolution of the light curve. The exponential rise might reflect emerging light from the shock front, analogous to a radiative precursor in a supernova shock breakout. The consequence of such a shock in the nova wind potentially explains many kinds of unusual phenomena in novae including early-stage variations and potentially dust f...

  19. Outburst-related period changes of recurrent nova CI aquilae

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R. E.; Honeycutt, R. K., E-mail: honey@astro.indiana.edu, E-mail: rewilson@ufl.edu [Astronomy Department, Indiana University, Swain Hall West, Bloomington, IN 47405 (United States)

    2014-11-01

    Pre-outburst and post-outburst light curves and post-outburst eclipse timings are analyzed to measure any period (P) change related to nova CI Aql's outburst of early 2000 and a mean post-outburst dP/dt, which then lead to estimates of the accreting component's rate of mass (M) change and its overall outburst-related change of mass over roughly a decade of observations. We apply a recently developed procedure for unified analysis of three timing-related data types (light curves, radial velocities, and eclipse timings), although with only light curves and timings in this case. Fits to the data are reasonably good without need for a disk in the light-curve model, although the disk certainly exists and has an important role in our post-outburst mass flow computations. Initial experiments showed that, although there seems to be an accretion hot spot, it has essentially no effect on derived outburst-related ΔP or on post-outburst dP/dt. Use of atomic time (HJED) in place of HJD also has essentially nil effect on ΔP and dP/dt. We find ΔP consistently negative in various types of solutions, although at best only marginally significant statistically in any one experiment. Pre-outburst HJD {sub 0} and P results are given, as are post-outburst HJD {sub 0}, P, and dP/dt, with light curves and eclipse times as joint input, and also with only eclipse time input. Post-outburst dP/dt is negative at about 2.4σ. Explicit formulae for mass transfer rates and epoch-to-epoch mass change are developed and applied. A known offset in the magnitude zero point for 1991-1994 is corrected.

  20. The panchromatic spectroscopic evolution of the classical CO nova V339 Del (Nova Del 2013) until X-ray turnoff

    CERN Document Server

    Shore, S N; Schwarz, G J; Teyssier, F M; Buil, C; Aquino, I De Gennaro; Page, K L; Osborne, J P; Scaringi, S; Starrfield, S; van Winckel, H; Williams, R E; Woodward, C E

    2016-01-01

    Classical novae are the product of thermonuclear runaway-initiated explosions occurring on accreting white dwarfs. V339 Del (Nova Delphinus 2013) was one of the brightest classical novae of the last hundred years. Spectroscopy and photometry are available from $\\gamma$-rays through infrared at stages that have frequently not been well observed. The complete data set is intended to provide a benchmark for comparison with modeling and for understanding more sparsely monitored historical classical and recurrent novae. This paper is the first in the series of reports on the development of the nova. We report here on the early stages of the outburst, through the X-ray active stage. A time sequence of optical, flux calibrated high resolution spectra was obtained with the Nordic Optical Telescope (NOT) using FIES simultaneously, or contemporaneously, with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope during the early stages of the outburst. These were supplemented with MERCATOR/HE...

  1. The Inter-Eruption Timescale of Classical Novae from Expansion of the Z Camelopardalis Shell

    CERN Document Server

    Shara, Michael M; Zurek, David; Martin, Christopher D; Neill, James D; Seibert, Mark

    2012-01-01

    The dwarf nova Z Camelopardalis is surrounded by the largest known classical nova shell. This shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts. The current size of the shell, its known distance, and the largest observed nova ejection velocity set a lower limit to the time since Z Cam's last outburst of 220 years. The brightest part of the Z Cam shell's radius is currently p ~ 1690 pixels. No expansion of the radius of the brightest part of the ejecta was detected, with an upper limit of pdot 5,000 years ago. However, including the important effect of deceleration as the ejecta sweeps up interstellar matter in its snowplow phase reduces the lower limit to 1300 years. This is the first strong test of the prediction of nova thermonuclear runaway theory that the inter-outburst times of classical novae are longer than 1000 yr. The intriguing suggestion ...

  2. Nova outburst modeling and its application to the recurrent nova phenomenon

    International Nuclear Information System (INIS)

    The thermonuclear runaway (TNR) theory for the cause of the common novae is reviewed. Numerical simulations of this theory were performed using an implicit hydrodynamic Lagrangian computer code. Relevant physical phenomena are explained with the simpler envelope-in-place calculations. Next the models that include accretion are discussed. The calculations agree very well with observations of common novae. The observational differences between common novae and recurrent novae are examined. We propose input parameters to the TNR model which can give the outburst characteristics of RS Ophiuchi and discuss the implications. This review is concluded with a brief discussion of two current topics in novae research: shear mixing on the white dwarf and Neon novae. 36 refs., 4 figs

  3. Nuclear reaction rates and the nova outburst

    International Nuclear Information System (INIS)

    In this paper we examined the consequences of improving the nuclear reaction library on our simulations of TNRs on 1.25M, WD and 1.35M, WDS. We have found that the changes in the rates have affected the nucleosynthesis predictions of our calculations but not, to any great extent, the gross features. In addition, we have used a lower mass accretion rate than in our previous studies in order to accrete (and eject) more material. This has, as expected, caused the peak values of some important parameters to increase over our previous studies at the same WD mass. However, because some important reaction rates have declined in the new compilation this has not increased the abundances for nuclei above aluminum and, in fact, they have declined while the abundances of both 26Al and 27Al have increased at both WD masses. In contrast, the abundance of 22Na has declined at both WD masses over the values predicted in our earlier work. This has important implications with respect to predictions of the observability of novae with INTEGRAL

  4. Infrared studies of Nova Scorpii 2014: an outburst in a symbiotic system sans an accompanying blast wave

    Science.gov (United States)

    Joshi, Vishal; Banerjee, D. P. K.; Ashok, N. M.; Venkataraman, V.; Walter, F. M.

    2015-10-01

    Near-IR (NIR) spectroscopy is presented for Nova Scorpii 2014. It is shown that the outburst occurred in a symbiotic binary system - an extremely rare configuration for a classical nova outburst to occur in but appropriate for the eruption of a recurrent nova of the T CrB class. We estimate the spectral class of secondary as M5III ± (two sub-classes). The maximum magnitude versus rate of decline relations give an unacceptably large value of 37.5 kpc for the distance. The spectra are typical of the He/N class of novae with strong He I and H lines. The profiles are broad and flat topped with full width at zero intensities approaching 9000-10 000 km s-1 and also have a sharp narrow component superposed which is attributable to emission from the giant's wind. Hot shocked gas, accompanied by X-rays and γ-rays, is expected to form when the high-velocity ejecta from the nova ploughs into the surrounding giant wind. Although X-ray emission was observed no γ-ray emission was reported. It is also puzzling that no signature of a decelerating shock is seen in the NIR, seen in similar systems like RS Oph, V745 Sco and V407 Cyg, as rapid narrowing of the line profiles. The small outburst amplitude and the giant secondary strongly suggest that Nova Sco 2014 could be a recurrent nova.

  5. TGRS observations of positron annihilation in classical novae

    International Nuclear Information System (INIS)

    The TGRS experiment on board the Wind spacecraft has many advantages as a sky monitor--broad field of view (∼2π centered on the south ecliptic pole), long life (1994-present), and stable low background and continuous coverage due to Wind's high altitude high eccentricity orbit. The Ge detector has sufficient energy resolution (3-4 keV at 511 keV) to resolve a cosmic positron annihilation line from the strong background annihilation line from β-decays induced by cosmic ray impacts on the instrument, if the cosmic line is Doppler-shifted by this amount. Such lines (blueshifted) are predicted from nucleosynthesis in classical novae. We have searched the entire TGRS database for 1995-1997 for this line, with negative results. In principle such a search could yield an unbiased upper limit on the highly-uncertain Galactic nova rate. We carefully examined the times around the known nova events during this period, also with negative results. The upper limit on the nova line flux in a 6-hr interval is typically -3photon cm-2 s-1 (4.6σ). We performed the same analysis for times around the outburst of Nova Vel 1999, obtaining a worse limit due to recent degradation of the detector response caused by cosmic ray induced damage

  6. Getting to know classical novae with Swift

    Science.gov (United States)

    Osborne, Julian P.

    2015-09-01

    Novae have been reported as transients for more than two thousand years. Their bright optical outbursts are the result of explosive nuclear burning of gas accreted from a binary companion onto a white dwarf. Novae containing a white dwarf close to the Chandrasekhar mass limit and accreting at a high rate are potentially the unknown progenitors of the type Ia supernovae used to measure the acceleration of the Universe. Swift X-ray observations have radically transformed our view of novae by providing dense monitoring throughout the outburst, revealing new phenomena in the super-soft X-rays from the still-burning white dwarf such as early extreme variability and half- to one-minute timescale quasi-periodic oscillations. The distinct evolution of this emission from the harder X-ray emission due to ejecta shocks has been clearly delineated. Soft X-ray observations allow the mass of the white dwarf, the mass burned and the mass ejected to be estimated. In combination with observations at other wavelengths, including the high spectral resolution observations of the large X-ray observatories, high resolution optical and radio imaging, radio monitoring, optical spectroscopy, and the detection of GeV gamma-ray emission from recent novae, models of the explosion have been tested and developed. I review nine novae for which Swift has made a significant impact; these have shown the signature of the components in the interacting binary system in addition to the white dwarf: the re-formed accretion disk, the companion star and its stellar wind.

  7. Getting to know Classical Novae with Swift

    CERN Document Server

    Osborne, Julian P

    2015-01-01

    Novae have been reported as transients for more than two thousand years. Their bright optical outbursts are the result of explosive nuclear burning of gas accreted from a binary companion onto a white dwarf. Novae containing a white dwarf close to the Chandrasekhar mass limit and accreting at a high rate are potentially the unknown progenitors of the type Ia supernovae used to measure the acceleration of the Universe. Swift X-ray observations have radically transformed our view of novae by providing dense monitoring throughout the outburst, revealing new phenomena in the super-soft X-rays from the still-burning white dwarf such as early extreme variability and half- to one-minute timescale quasi-periodic oscillations. The distinct evolution of this emission from the harder X-ray emission due to ejecta shocks has been clearly delineated. Soft X-ray observations allow the mass of the white dwarf, the mass burned and the mass ejected to be estimated. In combination with observations at other wavelengths, includi...

  8. Multi-wavelength observations of novae in outburst

    International Nuclear Information System (INIS)

    This review serves as the introduction to the observational studies of novae and I will mention a number of results that will be emphasized by other reviewers. Therefore, I will try to provide the physical framework for multi-wavelength observations as applied to studies of novae. I divide the outburst into phases based on the physical effects that are occurring at that time. The first phase is the rise to bolometric maximum and occurs on a convective time scale. The second phase is the rise to visual maximum and occurs on the time scale for the envelope to expand to ∼1012cm. The third phase is the time when the nova is emitting at constant bolometric luminosity, but declining optical magnitude, and it lasts until most of the accreted material has been either exhausted or eroded from the surface of the white dwarf. The fourth and final phase is the return is the return to quiescence (turn-off phase) and it occurs at the time that nuclear burning is ending. I will discuss each of these phases in turn and end with a discussion. 36 refs

  9. The awakening of a classical nova from hibernation

    CERN Document Server

    Mroz, P; Pietrukowicz, P; Szymanski, M K; Soszynski, I; Wyrzykowski, L; Poleski, R; Kozlowski, S; Skowron, J; Ulaczyk, K; Skowron, D; Pawlak, M

    2016-01-01

    Cataclysmic variable stars (CVs) are close binary systems consisting of a white dwarf (primary) that is accreting matter from a low-mass companion star (secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, over $10^4$ times in brightness, occur in classical novae and are caused by a thermonuclear runaway on the surface of the white dwarf. Such eruptions are thought to recur on timescales of $10^4-10^6$. In between, the system's properties depend primarily on the mass-transfer rate: if it is lower than a $10^{-9} M_{\\odot}$/year, the accretion becomes unstable and the matter is dumped onto the white dwarf during quasi-periodic dwarf nova outbursts. The hibernation hypothesis predicts that nova eruptions strongly affect the mass-transfer rate, keeping it high for centuries after the event. Subsequently, the mass-transfer rate should significantly decrease for $10^3-10^6$ years, starting the hibernation phase. After that the nova awakes again - with acc...

  10. Observations and predictions of EUV emission from classical novae

    International Nuclear Information System (INIS)

    Theoretical modeling of novae in outburst predicts that they should be active emitters of radiation both in the EUV and soft X-ray wavelengths twice during the outburst. The first time is very early in the outburst when only an all sky survey can detect them. This period lasts only a few hours. They again become bright EUV and soft X-ray emitters late in the outburst when the remnant object becomes very hot and is still luminous. The predictions imply both that a nova can remain very hot for months to years and that the peak temperature at this time strongly depends upon the mass of the white dwarf. It is important to observe novae at these late times because a measurement of both the flux and temperature can provide information about the mass of the white dwarf, the tun-off time scale, and the energy budget of the outburst. We review the existing observations of novae in late stages of their outburst and present some newly obtained data for GQ Mus 1983. We then provide results of new hydrodynamic simulations of novae in outburst and compare the predictions to the observations. 43 refs., 6 figs

  11. The spectroscopic evolution of the $\\gamma$-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae

    CERN Document Server

    Shore, S N; Schwarz, G J; Augusteijn, T; Cheung, C C; Walter, F M; Starrfield, S

    2013-01-01

    Nova Mon 2012 was the first classical nova to be detected as a high energy $\\gamma$-ray transient, by Fermi-LAT, before its optical discovery. We study a time sequence of high resolution optical echelle spectra (Nordic Optical Telescope) and contemporaneous NOT, STIS UV, and CHIRON echelle spectra (Nov 20/21/22). We use [O III] and H$\\beta$ line fluxs to constrain the properties of the ejecta. We derive the structure from the optical and UV line profiles and compare our measured line fluxes for with predictions using Cloudy with abundances from other ONe novae. Mon 2012 is confirmed as an ONe nova. We find E(B-V)=0.85$\\pm$0.05 and hydrogen column density $\\approx 5\\times 10^{21}$ cm$^{-2}$. The corrected continuum luminosity is nearly the same in the entire observed energy range as V1974 Cyg, V382 Mon, and Nova LMC 2000 at the same epoch after outburst. The distance, about 3.6 kpc, is quite similar to V1974 Cyg. The line profiles can be modeled using an axisymmetric bipolar geometry for the ejecta with variou...

  12. Infrared studies of Nova Scorpii 2014: an outburst in a symbiotic system sans an accompanying blast wave

    CERN Document Server

    Joshi, Vishal; Ashok, N M; Venkataraman, V; Walter, F M

    2015-01-01

    Near-IR spectroscopy is presented for Nova Scorpii 2014. It is shown that the outburst occurred in a symbiotic binary system - an extremely rare configuration for a classical nova outburst to occur in but appropriate for the eruption of a recurrent nova of the T CrB class. We estimate the spectral class of secondary as M5III $\\pm$ (two sub-classes). The maximum magnitude versus rate of decline (MMRD) relations give an unacceptably large value of 37.5 kpc for the distance. The spectra are typical of the He/N class of novae with strong HeI and H lines. The profiles are broad and flat topped with full width at zero intensities (FWZIs) approaching 9000-10000 km s$^{-1}$ and also have a sharp narrow component superposed which is attributable to emission from the giant's wind. Hot shocked gas, accompanied by X-rays and $\\gamma$ rays, is expected to form when the high velocity ejecta from the nova plows into the surrounding giant wind. Although X-ray emission was observed no $\\gamma$-ray emission was reported. It is...

  13. Convective Undershoot Mixing in Nova Outbursts - the Dependence on the Composition of the Underlying White Dwarf

    CERN Document Server

    Glasner, Ami S; Truran, James W

    2011-01-01

    We present here, for the first time, a 2D study of the undershoot convective mechanism in nova outbursts for a wide range of possible compositions of the layer underlying the accreted envelope. Previous surveys studied the mechanism only for solar matter accreted on top of a carbon oxygen white dwarf. Mixing with carbon was found to be crucial for the process since it dramatically enhanced the burning rates. According to observations and stellar evolution theory, in classical and recurrent novae the outermost underlying layer of the white dwarf can also be composed of ONe or pure Helium. In all the cases we examined we found significant amounts of mixing. We present the details of the burning rates and the convective flow for each underlying layer and discuss its significance for the long term debate as to the exact mechanism responsible for the enrichment of novae ejecta. Our results show that the undershoot convective dredge up model predict mixing amounts that can be consistent with observations in all the...

  14. Beacons in the sky. Classical novae vs. X-ray bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this review talk, we outline our understanding of the mechanisms leading to classical nova explosions and X-ray bursts, together with their associated nucleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (mainly 13C, 15N, and 17O), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based both on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of X-ray bursts as well as an insight into the nuclear uncertainties affecting critical reactions, for both novae and X-ray bursts, will also be presented. (author)

  15. Stellar Pyrotechnics: Nucleosynthesis in Classical Novae and X-Ray Bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this paper, we review our understanding of the mechanisms leading to classical nova explosions and x-ray bursts, together with their associated nu- cleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (mainly 13C, 15N, and 17O), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based both on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of x-ray bursts as well as an insight into the nuclear uncertainties affecting critical reactions, for both novae and x-ray bursts, are also reviewed

  16. Outburst characteristics of the dwarf nova V452 Cassiopeiae

    CERN Document Server

    Shears, Jeremy; Boyd, David; Brady, Steve; Miller, Ian; Pickard, Roger

    2008-01-01

    V452 Cas was thought to have rare outbursts, but monitoring from 2005 to 2008 has shown that the outburst interval is about one month and is weakly periodic. Observations of seven superoutbursts over the same period shows a very repeatable superoutburst period of 146 +/-16 days. Time series photometry of the 2007 September superoutburst shows that the outburst reached magnitude 15.3 at maximum and had an amplitude of 3.2 magnitudes. The outburst lasted for 12 days. Early superhumps with an amplitude of 0.3 magnitudes and period of Psh = 0.08943(7) days gave way to superhumps with decreasing amplitude and Psh = 0.08870(2) days later in the outburst, corresponding to a continuous period change Pdot/P = -9(2)x10-4 d-1 . V452 Cas has one of the smallest outburst amplitudes and shortest superoutburst periods of typical UGSU systems.

  17. Beacons in the sky: Classical novae vs. X-ray bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this review talk, we outline our understanding of the mechanisms leading to classical nova explosions and X-ray bursts, together with their associated nucleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (where 13C, 15N, and 17O constitute the likely imprints of many nova outbursts during the overall 10Gyr of Galactic history), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of X-ray bursts as well as an insight into the input nuclear physics requests, for both novae and X-ray bursts, will also be presented. (orig.)

  18. Dwarf novae in outburst: simultaneous ultraviolet and optical observations of UZ Serpentis, RX Andromedae and AH Herculis

    Energy Technology Data Exchange (ETDEWEB)

    Verbun, F.; Pringle, J.E.; Wade, R.A. (Cambridge Univ. (UK). Inst. of Astronomy); Echevarria, J.; Jones, D.H.P.; Argyle, R.W.; Schwarzenberg-Czerny, A. (Royal Greenwich Observatory, Hailsham (UK); Sussex Univ., Brighton (UK). Astronomy Centre); Dous, C. la; Schoembs, R. (Muenchen Univ. (Germany, F.R.). Sternwarte)

    1984-09-01

    Spectroscopic and photometric observations in the optical and ultraviolet wavelength regions made during outbursts of the three dwarf novae UZ Serpentis, RX Andromedae and AH Herculis are presented. The observations do not cover the rapid initial rise to outburst, but rather the peak and the subsequent decline. The overall changes of the continuum distributions are different in the three objects, and for UZ Ser evidence is presented that the distribution repeats from outburst to outburst, although the line strengths do not. The decline from outburst is characterized by a drop in flux at all wavelengths, the drop being faster at shorter wavelengths.

  19. Dwarf novae in outburst: simultaneous ultraviolet and optical observations of UZ Serpentis, RX Andromedae and AH Herculis

    International Nuclear Information System (INIS)

    Spectroscopic and photometric observations in the optical and ultraviolet wavelength regions made during outbursts of the three dwarf novae UZ Serpentis, RX Andromedae and AH Herculis are presented. The observations do not cover the rapid initial rise to outburst, but rather the peak and the subsequent decline. The overall changes of the continuum distributions are different in the three objects, and for UZ Ser evidence is presented that the distribution repeats from outburst to outburst, although the line strengths do not. The decline from outburst is characterized by a drop in flux at all wavelengths, the drop being faster at shorter wavelengths. (author)

  20. Discovery and outburst characteristics of the dwarf nova ASAS J224349+0809.5

    CERN Document Server

    Shears, Jeremy; Bolt, Greg; Hambsch, Franz-Josef; Krajci, Tom; Miller, Ian; Sabo, Richard; Staels, Bart

    2010-01-01

    We report the discovery of a new dwarf nova and our observations of its first confirmed superoutburst during 2009 October. The outburst amplitude was 6 magnitudes. The main outburst lasted 17 days and was followed 4 days later by a remarkable rebrightening. Superhumps were present during the main outburst, which confirms that it belongs to the SU UMa family. Initially the mean superhump period was Psh = 0.06965(17) d, but analysis of the O-C residuals showed a dramatic evolution in Psh during the outburst. During the first two-thirds of the plateau phase the period increased with dPsh/dt = +1.24(5) x 10-3. There was then an abrupt change following which the period decreased with dPsh/dt = -1.01(9) x 10-3. The amplitude of the superhumps also varied, with a maximum amplitude near the beginning of the outburst and a second maximum corresponding to the discontinuity in Psh. Analysis of archival data showed outbursts also occurred in October 2005, June 2006 and June 2007. Assuming that the superoutbursts are peri...

  1. An International Ultraviolet Explorer Archival Study of Dwarf Novae in Outburst

    CERN Document Server

    Hamilton, Ryan T; Sion, Edward M; Riedel, Adric R; Voyer, Elysse N; Marcy, John T; Lakatos, Sarah L

    2007-01-01

    We present a synthetic spectral analysis of nearly the entire far ultraviolet International Ultraviolet Explorer (IUE) archive of spectra of dwarf novae in or near outburst. The study includes 46 systems of all dwarf nova subtypes both above and below the period gap. The spectra were uniformly analyzed using synthetic spectral codes for optically thick accretion disks and stellar photospheres along with the best-available distance measurements or estimates. We present newly estimated accretion rates and discuss the implications of our study for disk accretion physics and CV evolution.

  2. OGLE Atlas of Classical Novae I. Galactic Bulge Objects

    CERN Document Server

    Mroz, P; Poleski, R; Soszynski, I; Szymanski, M K; Pietrzynski, G; Wyrzykowski, L; Ulaczyk, K; Kozlowski, S; Pietrukowicz, P; Skowron, J

    2015-01-01

    Classical novae eruptions are possible sources of lithium formation and gamma-rays emission. The remnant systems of novae eruptions can also become Type Ia supernovae. The contribution of novae to these phenomena depends on nova rates that are not well established for the Galaxy. Here, we directly measure the Galactic bulge nova rate of $13.9 \\pm 2.6$ yr$^{-1}$. This measurement is much more accurate than any previous measurement of this kind thanks to multiple years of bulge monitoring by the OGLE survey. Our sample consists of 39 novae eruptions, $\\sim$1/3 of which are OGLE-based discoveries. The long-term monitoring allows us to not only measure the nova rate but also to study in detail the light curves of 39 eruptions and over 80 post-nova candidates. We measured orbital periods for 9 post-novae and 9 novae, in 14 cases we procured the first estimates. The OGLE survey is very sensitive to the frequently erupting recurrent novae. We did not found any object similar to M31 2008-12a, which erupts once a year...

  3. Infrared accretion disc mapping of the dwarf nova V2051 Ophiuchi in outburst and in quiescence

    Science.gov (United States)

    Wojcikiewicz, E.; Baptista, R.

    2014-10-01

    Dwarf novae are compact binaries where a late-type star (the secondary) fills its Roche lobe and transfers matter to a companion white dwarf (the primary) via an accretion disc. They show outbursts which recur on timescales of weeks to years, where the accretion disc brightens by factors 20 to 100 either due to a thermal-viscous instability in the disc (DI model) or to a burst of enhanced mass-transfer from the secondary (MTI model). We report time-series of fast photometry of the dwarf nova V2051 Oph in the J and H bands, obtained with the CAMIV at the 1.6 m telescope of Observatório Pico dos Dias/Brazil, during the decline of an outburst in 2005 June, and in 2008 when the object was in quiescence. We modeled the ellipsoidal variations caused by the secondary to infer its contribution to the J and H fluxes, and fitted stellar atmosphere models to find a photometric parallatic distance of d = (111± 14)pc. Front-back brightness asymmetries in J and H-band eclipse maps along the decline from the 2005 outburst suggest that the accretion disc had a non-negligible opening angle which decreased as the disc cooled down. The time evolution of the disc radial temperature distribution along the outburst decline shows a cooling wave which accelerates as is travels inwards - in contradiction to a basic prediction from the DI model.

  4. NEAR-IR STUDIES OF RECURRENT NOVA V745 SCORPII DURING ITS 2014 OUTBURST

    International Nuclear Information System (INIS)

    The recurrent nova V745 Scorpii underwent its third known outburst on 2014 February 6. Infrared monitoring of the eruption on an almost daily basis, starting from 1.3 days after discovery, shows the emergence of a powerful blast wave generated by the high velocity nova ejecta exceeding 4000 km s–1 plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 108 K immediately after outburst commencement. The energetics of the outburst clearly surpass those of similar symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The shock does not show a free-expansion stage but rather shows a decelerative Sedov-Taylor phase from the beginning. Such strong shock fronts are known to be sites for γ-ray generation. V745 Sco is the latest nova, apart from five other known novae, to show γ-ray emission. It may be an important testbed to resolve the crucial question of whether or not all novae are generically γ-ray emitters by virtue of having a circumbinary reservoir of material that is shocked by the ejecta rather than γ-ray generation being restricted to only symbiotic systems with a shocked red giant (RG) wind. The lack of a free-expansion stage favors V745 Sco to have a density enhancement around the white dwarf (WD), above that contributed by a RG wind. Our analysis also suggests that the WD in V745 Sco is very massive and a potential progenitor for a future SN Ia explosion

  5. Non-LTE Luminosity and Abundance Diagnostics of Classical Novae in X-rays

    CERN Document Server

    Németh, Péter

    2013-01-01

    Classical novae are significant sources of interstellar material, especially carbon, nitrogen and oxygen. These standard candles are only behind supernovae and $\\gamma$-ray bursts as the third brightest objects in the sky, and the most probable progenitors of type Ia supernovae. After a nova outburst the system enters into the constant bolometric luminosity phase and the nova maintains a stable hydrogen burning in the surface layers of the white dwarf. As the expanding shell around the nova attenuates, progressively deeper and hotter layers become visible. At the end of the constant bolometric luminosity phase, the hottest layers are exposed and novae radiate X-rays. This work uses the static, plane-parallel model atmosphere code TLUSTY to calculate atmospheric structure and SYNSPEC to calculate synthetic X-ray spectra. It was necessary to incorporate atomic data for the highest ionization stages of elements ranging from hydrogen to iron in both programs. Atomic data on energy levels, bound-free, bound-bound ...

  6. ELEMENTAL ABUNDANCES IN THE EJECTA OF OLD CLASSICAL NOVAE FROM LATE-EPOCH SPITZER SPECTRA

    International Nuclear Information System (INIS)

    We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst, respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low-density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs (WDs). We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO WD.

  7. Multi-mission observations of the old nova GK Per during the 2015 outburst

    CERN Document Server

    Zemko, Polina; Luna, Gerardo Juan Manuel; Mukai, Koji

    2016-01-01

    The remarkable old nova and an intermediate polar (IP) - GK Per was observed with Swift, the Chandra HETG and NuSTAR during its recent dwarf nova (DN) outburst in March - April 2015. Monitoring the outburst, we noticed several processes occurring on different time scales, such as: the slow evolution of the very soft X-ray emission (below 0.6 keV) during the first two weeks of the outburst and the very fast saturation of the X-ray flux above 1 keV. The Swift UVOT lights curves also showed different behaviour, depending on the filter. The broad band X-ray spectra revealed the presence of at least three different emitting sources. The white dwarf (WD) spin was observed even in the very hard X-ray range of NuSTAR, indicating that the modulation is not due to absorption, in contrast to a typical IP. It is also supported by the similarity of the on-pulse and off-pulse X-ray spectra. We propose that the scenario when the inner accretion disk pushed towards the WD by the increased accretion obscures the lower WD pole...

  8. The $^{7}$Be II Resonance Lines in Two Classical Novae V5668 Sgr and V2944 Oph

    CERN Document Server

    Tajitsu, Akito; Naito, Hiroyuki; Arai, Akira; Kawakita, Hideyo; Aoki, Wako

    2016-01-01

    We report spectroscopic observations of the resonance lines of singly ionized $^{7}$Be in the blue-shifted absorption line systems found in the post-outburst spectra of two classical novae -- V5668 Sgr (Nova Sagittarii 2015 No.2) and V2944 Oph (Nova Ophiuchi 2015). The unstable isotope, $^{7}$Be, should has been created during the thermonuclear runaway (TNR) of these novae and decays to form $^{7}$Li within a short period (a half-life of 53.22 days). Confirmations of $^{7}$Be are the second and the third ones following the first case found in V339 Del by Tajitsu et al. (2015). The blue-shifted absorption line systems in both novae are clearly divided into two velocity components, both of which contain $^{7}$Be. This means that the absorbing gases in both velocity components consist of products of TNR. We estimate amounts of $^{7}$Be produced during outbursts of both novae and conclude that significant $^{7}$Li should have been created. These findings strongly suggest that the explosive production of $^{7}$Li ...

  9. Suzaku X-ray observation of the GK Persei dwarf nova outburst in 2015

    Science.gov (United States)

    Yuasa, Takayuki; Hayashi, Takayuki; Ishida, Manabu

    2016-06-01

    The intermediate polar GK Per exhibited a dwarf nova outburst in 2015 March-April. Suzaku X-ray telescope serendipitously captured the onset of the outburst during its pre-scheduled pointing observation spanning four days. In this paper, we present temporal and spectral analysis results of this outburst, together with those from archival data of quiescent obtained in 2009 and 2014. Our temporal analysis confirmed previously reported spin modulation of X-ray count rates in outburst with a white dwarf (WD) spin period of PWD = 351.4 ± 0.5 s. The modulation is also detected in the hard X-ray band (16-60 keV), and spectral modelling of the absorption suggests obscuration by a dense absorption with a line-of-sight column density of NH > 1023 cm-2. A complex time evolution of spin modulation profiles is seen; the spin minimum phase shifts from phase ˜0.25 in the first half of the observation to ˜0.65 in the second one, and the pulse shape significantly changes epoch by epoch. Spectral fitting in the Fe K α band revealed an increase of the fluorescent line equivalent width, from ˜80 eV (quiescent) to ˜140 eV (outburst). The equivalent widths of He-like and H-like Fe K α are consistent with being constant at ˜40 eV in the two states. Broad-band spectral fitting in the 2-60 keV band resulted in a sub-solar Fe abundance of ˜0.1 Z⊙ and the maximum plasma temperature kTmax ˜ 50-60 keV when the isobaric cooling-flow model was applied. Based on the very small temperature change against a 6-7 times increased accretion rate, the accretion geometry in early outburst is discussed.

  10. Photometric evolution of the 2016 outburst of recurrent Nova LMC 1968: the first three weeks

    CERN Document Server

    Munari, U; Hambsch, F -J; Frigo, A

    2016-01-01

    Optical (BVRI) photometry of the first three weeks of the 2016 outburst of the recurrent Nova LMC 1968 is presented and discussed. The 2016 I-band light-curve is an exact replica, even in the most minute details, of that for the 2010 eruption. The maximum is inferred to have occurred on 2016 Jan 21.2 at I=11.5 mag, corresponding to an absolute magnitude M(I)=-7.15. A ~1 day plateau is present in all bands about six days past optical maximum, simultaneous with the emergence of super-soft X-ray emission in Swift observations, signalling the widespread ionization of the ejecta. The nova entered a much longer plateau about 9 days past maximum, governed by the brightness of the white dwarf, now directly visible and still nuclearly burning on its surface. An outburst recurrence mean period of ~955 days (2.6 yrs) would fit both the OGLE inter-season gaps and the observed intervals between previous outburts.

  11. Recent advances in the modelling of classical novae and type I X-ray bursts

    International Nuclear Information System (INIS)

    Classical nova outbursts and type I X-ray bursts are thermonuclear stellar explosions driven by charged-particle reactions. Extensive numerical simulations of nova explosions have shown that the accreted envelopes attain peak temperatures between 0.1 and 0.4 GK, for about several hundred seconds, and therefore, their ejecta is expected to show signatures of significant nuclear activity. Indeed, it has been claimed that novae play some role in the enrichment of the interstellar medium through a number of intermediate-mass elements. This includes 17O, 15N, and 13C, systematically overproduced in huge amounts with respect to solar abundances, with a lower contribution to a number of species with A7Li, 19F, or 26Al. In this review, we present new 1-D hydrodynamic models of classical nova outbursts, from the onset of accretion up to the explosion and ejection phases. Special emphasis is put on their gross observational properties (including constraints from meteoritic presolar grains and potential gamma-ray signatures) and on their associated nucleosynthesis. Multidimensional models of mixing at the core-envelope interface during outbursts will also be presented. The impact of nuclear uncertainties on the final yields will be also outlined. Detailed analysis of the relevant reactions along the main nuclear path for type I X-ray bursts has only been scarcely addressed, mainly in the context of parameterized one-zone models. Here, we present a detailed study of the nucleosynthesis and nuclear processes powering type I X-ray bursts. The reported bursts have been computed by means of a spherically symmetric (1D), Lagrangian, hydrodynamic code, linked to a nuclear reaction network that contains 325 isotopes (from 1H to 107Te), and 1392 nuclear processes. These evolutionary sequences, followed from the onset of accretion up to the explosion and expansion stages, have been performed for two different metallicities to explore the dependence between the extension of the main

  12. The panchromatic spectroscopic evolution of the classical CO nova V339 Delphini (Nova Del 2013) until X-ray turnoff

    Science.gov (United States)

    Shore, S. N.; Mason, E.; Schwarz, G. J.; Teyssier, F. M.; Buil, C.; De Gennaro Aquino, I.; Page, K. L.; Osborne, J. P.; Scaringi, S.; Starrfield, S.; van Winckel, H.; Williams, R. E.; Woodward, C. E.

    2016-05-01

    Context. Classical novae are the product of thermonuclear runaway-initiated explosions occurring on accreting white dwarfs. Aims: V339 Del (Nova Delphinus 2013) was one of the brightest classical novae of the last hundred years. Spectroscopy and photometry are available from γ-rays through infrared at stages that have frequently not been observed well. The complete data set is intended to provide a benchmark for comparison with modeling and for understanding more sparsely monitored historical classical and recurrent novae. This paper is the first in the series of reports on the development of the nova. We report here on the early stages of the outburst, through the X-ray active stage. Methods: A time sequence of optical, flux calibrated high resolution spectra was obtained with the Nordic Optical Telescope (NOT) using FIES simultaneously, or contemporaneously, with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope during the early stages of the outburst. These were supplemented with Mercator/HERMES optical spectra. High resolution IUE ultraviolet spectra of OS And 1986, taken during the Fe curtain phase, served as a template for the distance determination. We used standard plasma diagnostics (e.g., [O III] and [N II] line ratios, and the Hβ line flux) to constrain electron densities and temperatures of the ejecta. Using Monte Carlo modeling of the ejecta, we derived the structure, filling factor, and mass from comparisons of the optical and ultraviolet line profiles. Results: We derive an extinction of E(B - V) = 0.23 ± 0.05 from the spectral energy distribution, the interstellar absorption, and H I emission lines. The distance, about 4-4.5 kpc, is in agreement with the inferred distance from near infrared interferometry. The maximum velocity was about 2500 km s-1, measured from the UV resonance and optical profiles. The ejecta showed considerable fine structure in all transitions, much of which persisted as emission knots. The

  13. Near-infrared studies of V5558 Sgr: an unusually slow nova with multiple outbursts

    CERN Document Server

    Das, Ramkrishna; Nandi, Arpita; Ashok, N M; Mondal, Soumen

    2014-01-01

    We present near-infrared (1-2.5 $\\mu$m) $JHK$ photo-spectroscopic results of the unusually slow nova V5558 Sgr (2007). V5558 Sgr showed a slow climb to maximum that lasted for about 60 days and then underwent at least five strong secondary outbursts. We have analyzed the optical light curve to derive large t${_2}$ and t${_3}$ values of 281 $\\pm$ 3 and 473 $\\pm$ 3 days respectively. An alternate approach is adopted to derive a distance estimate of 1.55 $\\pm$ 0.25 kpc as conventional MMRD relation may not be applicable for a slow nova. In the pre-maxima stage the spectra showed narrow (FWHM $\\sim$ 400 - 550 km s$^{-1}$) and strong emission lines of Paschen and Brackett series with prominent P-Cygni components. In the later phase the spectra show significant changes with the development of strong and broad ($\\sim$ 1000 km s$^{-1}$) emission lines of HI, HeI, OI, and NI and some uncommon Fe II emission lines. No evidence of dust formation is seen. V5558 Sgr has been shown to be a rare hybrid nova showing a transi...

  14. Simultaneous photometry and echelle-spectroscopy of the dwarf nova BZ Ursae Majoris during the 2005 January Outburst

    CERN Document Server

    Neustroev, V V; Michel, R

    2006-01-01

    We report simultaneous photometric and echelle-spectroscopic observations of the dwarf nova BZ UMa during which we were lucky to catch the system at the onset of an outburst, the development of which we traced in detail from quiescence to early decline. The outburst had a precursor, and was of a short duration (~5 days) with a highly asymmetrical light curve. On the rise we observed a `jump' during which the brightness almost doubled over the course of half an hour. Power spectra analysis revealed well-defined oscillations with period of ~42 minutes. Using Doppler tomography we found that the unusual emission distribution detected in quiescence held during the outburst. After the maximum a new emission source arose, from the inner hemisphere of the secondary star, which became the brightest at that time. We analyse this outburst in terms of `inside-out' and `outside-in' types, in order to determine which of these types occured in BZ UMa.

  15. The Dusty Nova: An Examination of Dust Production and Processing in the Ejecta of Classical Novae

    Science.gov (United States)

    Helton, L. A.; Evans, A.; Woodward, C. E.; Gehrz, R. D.; Vacca, W.

    2014-12-01

    Classical novae (CNe) are known to frequently produce dust in their ejecta. Infrared observations have revealed that the dust produced can be of a variety of different species, including silicates, amorphous carbon, hydrocarbons, and silicon carbide. Due to their relatively rapid evolution, CNe provide unique laboratories for the examination of the processes of dust condensation, grain growth, and destruction. Here we present analysis of the near- to mid-IR spectra of a number of recent dust forming novae, including V2361 Cyg, V2362 Cyg, and V1280 Sco. We discuss the implications for our understanding of dust formation and processing with particular emphasis on the role of hydrocarbon species.

  16. The Curious Case of ASAS J174600-2321.3: an Eclipsing Symbiotic Nova in Outburst?

    CERN Document Server

    Huemmerich, Stefan; Tisserand, Patrick; Bernhard, Klaus

    2015-01-01

    The star ASAS J174600-2321.3 was found to exhibit peculiar photometric variability (conspicuous brightening of about 4 magnitudes (V), fast luminosity declines, intrinsic pulsations). It was rejected as an RCB candidate in recent investigations on spectroscopic grounds. We have collected and present all available data from public sky surveys, photometric catalogues, and the literature. From an analysis of these data, we have identified ASAS J174600-2321.3 as a long-period eclipsing binary (Porb = 1011.5 days). The primary star, which is probably a white dwarf, is currently in outburst and exhibits the spectral characteristics of a reddened, early F-type supergiant; the secondary star is a giant of spectral type late M. We discuss the possible origin of the observed brightening, which is related to the primary component. ASAS J174600-2321.3 is most certainly an eclipsing symbiotic binary - probably a symbiotic nova of GCVS type NC - that is currently in outburst. However, further photometric and spectroscopic ...

  17. The 2011 outburst of recurrent nova T PYX: Radio observations reveal the ejecta mass and hint at complex mass loss

    International Nuclear Information System (INIS)

    Despite being the prototype of its class, T Pyx is arguably the most unusual and poorly understood recurrent nova. Here, we use radio observations from the Karl G. Jansky Very Large Array to trace the evolution of the ejecta over the course of the 2011 outburst of T Pyx. The radio emission is broadly consistent with thermal emission from the nova ejecta. However, the radio flux began rising surprisingly late in the outburst, indicating that the bulk of the radio-emitting material was either very cold, or expanding very slowly, for the first ∼50 days of the outburst. Considering a plausible range of volume filling factors and geometries for the ejecta, we find that the high peak flux densities of the radio emission require a massive ejection of (1-30) × 10–5 M ☉. This ejecta mass is much higher than the values normally associated with recurrent novae, and is more consistent with a nova on a white dwarf well below the Chandrasekhar limit.

  18. EXPANDED VERY LARGE ARRAY NOVA PROJECT OBSERVATIONS OF THE CLASSICAL NOVA V1723 AQUILAE

    International Nuclear Information System (INIS)

    We present radio light curves and spectra of the classical nova V1723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of V1723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of V1723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

  19. The γ-ray sources in classical novae

    Science.gov (United States)

    Sun, Weichao; Zhu, Chunhua; Wang, Zhaojun; Lü, Guoliang

    2016-08-01

    The interaction between novae ejecta and accretion disks or circumbinary (CB) disks surrounding nova systems based on the diffusive shock acceleration (DSA) mechanism are investigated. Results suggest that interaction between the novae ejecta and CB disks most probably produce γ-rays. Both leptonic and hadronic scenarios can feasibly produce γ-rays in CB disks. A grid is calculated in order to discuss the γ-ray sources in classical novae (CNe), and results indicated that the mass of a white dwarf and the orbit period in CNe can greatly affect the production of γ-rays. According to the proposed grid and synthesis population method, it is estimated that the percentage of CNe that can produce γ-rays ranges from approximately 0.17 % to 51 % for leptonic scenarios when the magnetic field strength in the shock region ranges from 0.005 G to 0.02 G. The occurrence rate of γ-ray CNe ranges from approximately 1 yr^{-1} to 27 yr^{-1} in the galaxy. The corresponding percentage ranges from approximately 64 % to 97 % in hadronic scenarios, while the occurrence rate of γ-ray CNe ranges from approximately 35 yr^{-1} to 52 yr^{-1} in the galaxy.

  20. A Detailed Photometric and Spectroscopic Study of the 2011 Outburst of the Recurrent Nova T Pyxidis from 0.8 to 250 Days after Discovery

    Science.gov (United States)

    Surina, F.; Hounsell, R. A.; Bode, M. F.; Darnley, M. J.; Harman, D. J.; Walter, F. M.

    2014-05-01

    We investigated the optical light curve of T Pyx during its 2011 outburst by compiling a database of Solar Mass Ejection Imager (SMEI) and AAVSO observations. The SMEI light curve, providing unprecedented detail covering t = 1.5-49 days post-discovery, was divided into four phases based on the idealized nova optical light curve: the initial rise (1.5-3.3 days), the pre-maximum halt (3.3-13.3 days), the final rise (14.7-27.9 days), and the early decline (27.9+ days). The SMEI light curve contains a strongly detected period of 1.44 ± 0.05 days during the pre-maximum halt phase. These oscillations resemble those found in recent thermonuclear runaway models arising from instabilities in the expanding envelope. No spectral variations that mirror the light curve periodicity were found, however. The marked dip at t ~ 22-24 days just before the light curve maximum at t = 27.9 days may represent the same (shorter duration) phenomenon seen in other novae observed by SMEI and present in some model light curves. The spectra from the 2 m Liverpool Telescope and SMARTS 1.5 m telescope were obtained from t = 0.8-80.7 and 155.1-249.9 days, covering the major phases of development. The nova was observed very early in its rise where a distinct high-velocity ejection phase was evident with initially derived V ej ~ 4000 km s-1. A marked drop occurred at t = 5.7 days, and then a gradual increase in derived V ej to stabilize at ~1500 km s-1 at the pre-maximum halt. Here, we propose two different stages of mass loss, a short-lived phase occurring immediately after outburst and lasting ~6 days, followed by a more steadily evolving and higher mass loss phase. The overall spectral development follows that typical of a classical nova and comparison with the photometric behavior reveals consistencies with the simple evolving pseudo-photosphere model of the nova outburst. Comparing optical spectra to X-ray and radio light curves, weak [Fe X] 6375 Å emission was marginally detected before the

  1. Explosive lithium production in the classical nova V339 Del (Nova Delphini 2013)

    CERN Document Server

    Tajitsu, Akito; Naito, Hiroyuki; Arai, Akir; Aoki, Wako

    2015-01-01

    The origin of lithium (Li) and its production process have long been an unsettled question in cosmology and astrophysics. Candidates environments of Li production events or sites suggested by previous studies include big bang nucleosynthesis, interactions of energetic cosmic rays with interstellar matter, evolved low mass stars, novae, and supernova explosions. Chemical evolution models and observed stellar Li abundances suggest that at least half of the present Li abundance may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. However, no direct evidence for the supply of Li from stellar objects to the Galactic medium has yet been found. Here we report on the detection of highly blue-shifted resonance lines of the singly ionized radioactive isotope of beryllium, $^{7}$Be, in the near ultraviolet (UV) spectra of the classical nova V339 Del (Nova Delphini 2013). Spectra were obtained 38 to 48 days after the explosion. $^{7}$Be decays to form $^{7}$Li within a short time (half-li...

  2. SWIFT X-RAY OBSERVATIONS OF CLASSICAL NOVAE. II. THE SUPER SOFT SOURCE SAMPLE

    International Nuclear Information System (INIS)

    The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10 keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000 Å) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations. The data set shows that the faster novae have an early hard X-ray phase that is usually missing in slower novae. The Super Soft X-ray phase occurs earlier and does not last as long in fast novae compared to slower novae. All the Swift novae with sufficient observations show that novae are highly variable with rapid variability and different periodicities. In the majority of cases, nuclear burning ceases less than three years after the outburst begins. Previous relationships, such as the nuclear burning duration versus t2 or the expansion velocity of the eject and nuclear burning duration versus the orbital period, are shown to be poorly correlated with the full sample indicating that additional factors beyond the white dwarf mass and binary separation play important roles in the evolution of a nova outburst. Finally, we confirm two optical phenomena that are correlated with strong, soft X-ray emission which can be used to further increase the efficiency of X-ray campaigns.

  3. X-ray grating observations of recurrent nova T Pyxidis during the 2011 outburst

    Energy Technology Data Exchange (ETDEWEB)

    Tofflemire, Benjamin M.; Orio, Marina [Astronomy Department, University of Wisconsin-Madison, 475 N. Charter St., WI 53711 (United States); Page, Kim L.; Osborne, Julian P. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco [Department of Physics and Astronomy, Padova University, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Maxwell, Michael [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom)

    2013-12-10

    The recurrent nova T Pyx was observed with the X-ray gratings of Chandra and XMM-Newton, 210 and 235 days, respectively, after the discovery of the 2011 April 14 outburst. The X-ray spectra show prominent emission lines of C, N, and O, with broadening corresponding to an FWHM of ∼2000-3000 km s{sup –1}, and line ratios consistent with high-density plasma in collisional ionization equilibrium. On day 210 we also measured soft X-ray continuum emission that appears to be consistent with a white dwarf (WD) atmosphere at a temperature ∼420,000 K, partially obscured by anisotropic, optically thick ejecta. The X-ray continuum emission is modulated with the photometric and spectroscopic period observed in quiescence. The continuum at day 235 indicated a WD atmosphere at a consistent effective temperature of 25 days earlier, but with a lower flux. The effective temperature indicates a mass of ∼1 M {sub ☉}. The conclusion of partial WD obscuration is supported by the complex geometry of non-spherically symmetric ejecta confirmed in recent optical spectra obtained with the Southern African Large Telescope in November and December of 2012. These spectra exhibited prominent [O III] nebular lines with velocity structures typical of bipolar ejecta.

  4. X-Ray Grating Observations of Recurrent Nova T Pyxidis During The 2011 Outburst

    CERN Document Server

    Tofflemire, Benjamin M; Page, Kim L; Osborne, Julian P; Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco; Maxwell, Michael

    2013-01-01

    The recurrent nova T Pyx was observed with the X-ray gratings of Chandra and XMM-Newton, 210 and 235 days, respectively, after the discovery of the 2011 April 14 outburst. The X-ray spectra show prominent emission lines of C, N, and O, with broadening corresponding to a full width at half maximum of ~2000-3000 km/s, and line ratios consistent with high-density plasma in collisional ionization equilibrium. On day 210 we also measured soft X-ray continuum emission that appears to be consistent with a white dwarf (WD) atmosphere at a temperature ~420,000 K, partially obscured by anisotropic, optically thick ejecta. The X-ray continuum emission is modulated with the photometric and spectroscopic period observed in quiescence. The continuum at day 235 indicated a WD atmosphere at a consistent effective temperature of 25 days earlier, but with a lower flux. The effective temperature indicates a mass of ~1 solar mass. The conclusion of partial WD obscuration is supported by the complex geometry of non-spherically-sy...

  5. The 2011 Outburst of Recurrent Nova T Pyx: X-ray Observations Expose the White Dwarf Mass and Ejection Dynamics

    CERN Document Server

    Chomiuk, Laura; Mukai, Koji; Sokoloski, J L; Rupen, Michael P; Page, Kim L; Osborne, Julian P; Kuulkers, Erik; Mioduszewski, Amy J; Roy, Nirupam; Weston, Jennifer; Krauss, Miriam I

    2014-01-01

    The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and became the subject of an intensive multi-wavelength observational campaign. We analyze data from the Swift and Suzaku satellites to produce a detailed X-ray light curve augmented by epochs of spectral information. X-ray observations yield mostly non-detections in the first four months of outburst, but both a super-soft and hard X-ray component rise rapidly after Day 115. The super-soft X-ray component, attributable to the photosphere of the nuclear-burning white dwarf, is relatively cool (~45 eV) and implies that the white dwarf in T Pyx is significantly below the Chandrasekhar mass (~1 M_sun). The late turn-on time of the super-soft component yields a large nova ejecta mass (>~10^-5 M_sun), consistent with estimates at other wavelengths. The hard X-ray component is well fit by a ~1 keV thermal plasma, and is attributed to shocks internal to the 2011 nova ejecta. The presence of a strong oxygen line in this thermal plasma on Day 194...

  6. Hydrogen Burning of 17O in Classical Novae

    International Nuclear Information System (INIS)

    We report on the observation of a previously unknown resonance at ERlab=194.1±0.6 keV in the 17O(p,α)14N reaction, with a measured resonance strength ωγpα=1.6±0.2 meV. We studied in the same experiment the 17O(p,γ)18F reaction by an activation method and the resonance-strength ratio was found to be ωγpα/ωγpγ=470±50. The corresponding excitation energy in the 18F compound nucleus was determined to be 5789.8±0.3 keV by γ-ray measurements using the 14N(α,γ)18F reaction. These new resonance properties have important consequences for 17O nucleosynthesis and γ-ray astronomy of classical novae

  7. The 2011 outburst of recurrent nova T Pyx: X-ray observations expose the white dwarf mass and ejection dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chomiuk, Laura [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Nelson, Thomas [School of Physics and Astronomy, University of Minnesota, 115 Church Street SE, Minneapolis, MN 55455 (United States); Mukai, Koji [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Sokoloski, J. L.; Weston, Jennifer [Columbia Astrophysics Laboratory, Columbia University, New York, NY (United States); Rupen, Michael P.; Mioduszewski, Amy J.; Krauss, Miriam I. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Page, Kim L.; Osborne, Julian P. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Kuulkers, Erik [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Caada, Madrid (Spain); Roy, Nirupam, E-mail: chomiuk@pa.msu.edu [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-06-20

    The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and became the subject of an intensive multi-wavelength observational campaign. We analyze data from the Swift and Suzaku satellites to produce a detailed X-ray light curve augmented by epochs of spectral information. X-ray observations yield mostly non-detections in the first four months of outburst, but both a super-soft and hard X-ray component rise rapidly after Day 115. The super-soft X-ray component, attributable to the photosphere of the nuclear-burning white dwarf, is relatively cool (∼45 eV) and implies that the white dwarf in T Pyx is significantly below the Chandrasekhar mass (∼1 M {sub ☉}). The late turn-on time of the super-soft component yields a large nova ejecta mass (≳ 10{sup –5} M {sub ☉}), consistent with estimates at other wavelengths. The hard X-ray component is well fit by a ∼1 keV thermal plasma, and is attributed to shocks internal to the 2011 nova ejecta. The presence of a strong oxygen line in this thermal plasma on Day 194 requires a significantly super-solar abundance of oxygen and implies that the ejecta are polluted by white dwarf material. The X-ray light curve can be explained by a dual-phase ejection, with a significant delay between the first and second ejection phases, and the second ejection finally released two months after outburst. A delayed ejection is consistent with optical and radio observations of T Pyx, but the physical mechanism producing such a delay remains a mystery.

  8. CNO abundances and hydrodynamic models of the nova outburst. II - 1.00 solar mass models with enhanced carbon and oxygen

    Science.gov (United States)

    Starrfield, S.; Sparks, W. M.; Truran, J. W.

    1974-01-01

    Results of a computation of a variety of evolutionary sequences involving thermonuclear runaways in the hydrogen-rich envelopes of 1.00-solar-mass carbon-oxygen white dwarfs. The evidence concerning the location of the outburst in the nova system is reexamined, and it is concluded that the white dwarf is the seat of the outburst. An order-of-magnitude argument is presented which indicates that for a 1.00-solar-mass white dwarf it is impossible to achieve mass ejection without an energy generation of approximately 10 to the 16th ergs/g/sec. A description is given of models with low nuclear enhancements that do not produce an outburst, although their evolution has certain implications for the cause of the dwarf-nova outburst. The results for models that produced a nova outburst are then presented, and on the basis of these results it is found possible to explain continuous ejection, Kukarkin and Parenago's (1934) relationship, and other gross features of the nova phenomena.

  9. EVIDENCE FOR AN FU ORIONIS-LIKE OUTBURST FROM A CLASSICAL T TAURI STAR

    International Nuclear Information System (INIS)

    We present pre- and post-outburst observations of the new FU Orionis-like young stellar object PTF 10qpf (also known as LkHα 188-G4 and HBC 722). Prior to this outburst, LkHα 188-G4 was classified as a classical T Tauri star (CTTS) on the basis of its optical emission-line spectrum superposed on a K8-type photosphere and its photometric variability. The mid-infrared spectral index of LkHα 188-G4 indicates a Class II-type object. LkHα 188-G4 exhibited a steady rise by ∼1 mag over ∼11 months starting in August 2009, before a subsequent more abrupt rise of >3 mag on a timescale of ∼2 months. Observations taken during the eruption exhibit the defining characteristics of FU Orionis variables: (1) an increase in brightness by ∼>4 mag, (2) a bright optical/near-infrared reflection nebula appeared, (3) optical spectra are consistent with a G supergiant and dominated by absorption lines, the only exception being Hα which is characterized by a P Cygni profile, (4) near-infrared spectra resemble those of late K-M giants/supergiants with enhanced absorption seen in the molecular bands of CO and H2O, and (5) outflow signatures in H and He are seen in the form of blueshifted absorption profiles. LkHα 188-G4 is the first member of the FU Orionis-like class with a well-sampled optical to mid-infrared spectral energy distribution in the pre-outburst phase. The association of the PTF 10qpf outburst with the previously identified CTTS LkHα 188-G4 (HBC 722) provides strong evidence that FU Orionis-like eruptions represent periods of enhanced disk accretion and outflow, likely triggered by instabilities in the disk. The early identification of PTF 10qpf as an FU Orionis-like variable will enable detailed photometric and spectroscopic observations during its post-outburst evolution for comparison with other known outbursting objects.

  10. Evidence for an FU Orionis Outburst from a Classical T Tauri Star

    CERN Document Server

    Miller, Adam A; Covey, Kevin R; Poznanski, Dovi; Silverman, Jeffrey M; Kleiser, Io K W; Rojas-Ayala, Barbara; Muirhead, Philip S; Cenko, S Bradley; Bloom, Joshua S; Kasliwal, Mansi M; Filippenko, Alexei V; Law, Nicholas M; Ofek, Eran O; Dekany, Richard G; Rahmer, Gustavo; Hale, David; Smith, Roger; Quimby, Robert M; Nugent, Peter; Jacobsen, Janet; Zolkower, Jeff; Velur, Viswa; Walters, Richard; Henning, John; Bui, Khanh; McKenna, Dan; Kulkarni, Shrinivas R; Klein, Christopher R

    2010-01-01

    We present pre- and post-outburst observations of the new FU Orionis-like young stellar object Lk Halpha 188-G4 (also known as HBC 722 and PTF 10qpf). Prior to this outburst, Lk Halpha 188-G4 would have been classified as a classical T Tauri star on the basis of its optical emission-line spectrum superposed on a K8-type photosphere, and photometric variability. The mid-infrared spectral index of Lk Halpha 188-G4 indicates a Class II type object. Lk Halpha 188-G4 exhibited a steady rise by ~1 mag over ~11 months starting in Aug. 2009, before a subsequent more abrupt rise of >3 mag on a time scale of ~2 months. Observations taken during and after eruption exhibit all of the defining characteristics of FU Orionis variables: (i) Lk Halpha 188-G4 increased in brightness by >4 mag, (ii) a bright optical/near-infrared reflection nebula has now appeared (iii) optical spectra in the outburst phase are consistent with a G supergiant and dominated by absorption lines, the only exception being Halpha which is characteriz...

  11. Binary Orbits as the Driver of Gamma-Ray Emission and Mass Ejection in Classical Novae

    Science.gov (United States)

    Chomiuk, Laura; Linford, Justin D.; Yang, Jun; O'Brien, T. J.; Paragi, Zsolt; Mioduszewski, Amy J.; Beswick, R. J.; Cheung, C. C.; Mukai, Koji; Nelson, Thomas

    2014-01-01

    Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10 (sup -4) solar masses of material at velocities exceeding 1,000 kilometers per second.However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at giga-electronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion..At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are gamma-ray emitters.

  12. The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst. II.The optically thin phase and the structure of the ejecta in recurrent novae

    CERN Document Server

    Shore, S N; Aquino, I De Gennaro; Augusteijn, T; Walter, F M; Starrfield, S; Sion, E M

    2012-01-01

    We continue our study of the physical properties of the recurrent nova T Pyx, focussing on the structure of the ejecta in the nebular stage of expansion during the 2011 outburst. The nova was observed contemporaneously with the Nordic Optical Telescope (NOT), at high resolution spectroscopic resolution (R ~ 65000) on 2011 Oct. 11 and 2012 Apr. 8 (without absolute flux calibration), and with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope, at high resolution (R ~ 30000) on 2011 Oct. 10 and 2012 Mar. 28 (absolute fluxes). We use standard plasma diagnostics (e.g. [O III] and [N II] line ratios and the H$\\beta$ line fluxes) to constrain electron densities and temperatures. Using Monte Carlo modeling of the ejecta, we derive the structure and filling factor from comparisons to the optical and ultraviolet line profiles. The ejecta can be modeled using an axisymmetric conical -- bipolar -- geometry with a low inclination of the axis to the line of sight, i=15+/-5 degrees, compatible...

  13. The January 2015 outburst of a red nova in M31

    Czech Academy of Sciences Publication Activity Database

    Kurtenkov, A.A.; Pessev, P.; Tomov, T.; Barsukova, E.A.; Fabrika, S.; Vida, K.; Hornoch, Kamil; Ovcharov, E.P.; Goranskij, V.P.; Valeev, A.F.; Molnár, L.; Sárneczky, K.; Kostov, A.; Nedialkov, P.; Valenti, S.; Geier, S.; Wiersema, K.; Henze, M.; Shafter, A.W.; Dimitrova, R.V.M.; Popov, V.N.; Stritzinger, M.

    2015-01-01

    Roč. 578, June (2015), L10/1-L10/5. ISSN 0004-6361 Institutional support: RVO:67985815 Keywords : novae * cataclysmic variables Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  14. X-ray nova MAXI J1828-249. Evolution of the broadband spectrum during its 2013-2014 outburst

    CERN Document Server

    Grebenev, S A; Burenin, R A; Krivonos, R A; Mescheryakov, A V

    2016-01-01

    Based on data from the SWIFT, INTEGRAL, MAXI/ISS orbital observatories, and the ground-based RTT-150 telescope, we have investigated the broadband (from the optical to the hard X-ray bands) spectrum of the X-ray nova MAXI J1828-249 and its evolution during the outburst of the source in 2013-2014. The optical and infrared emissions from the nova are shown to be largely determined by the extension of the power-law component responsible for the hard X-ray emission. The contribution from the outer cold regions of the accretion disk, even if the X-ray heating of its surface is taken into account, turns out to be moderate during the source's "high" state (when a soft blackbody emission component is observed in the X-ray spectrum) and is virtually absent during its "low" ("hard") state. This result suggests that much of the optical and infrared emissions from such systems originates in the same region of main energy release where their hard X-ray emission is formed. This can be the Compton or synchro-Compton radiati...

  15. Outburst of a WZ Sge-type dwarf nova, AL Com in 2007

    CERN Document Server

    Uemura, M; Sasada, M; Schmeer, P; Miller, I; Ohsugi, T; Yamashita, T; Kawabata, K S; Isogai, M; Sato, S; Kino, M

    2008-01-01

    We report photometric observations of AL Com during its rare outburst in 2007. The light curve is reminiscent of its past superoutbursts in 1995 and 2001, except for the rebrightening phase after the main superoutburst. During the rebrightening phase in 2007, we found clear modulations between V=16.2-15.2. In conjunction with the lack of prominent superhumps in our time-series observations, the modulations can most naturally be interpreted as repetitive short rebrightenings with a cycle of 1-2 days. The rebrightening characteristics in 2007 are different from those in 1995 and 2001. This indicates that the type of rebrightenings in WZ Sge stars depends not on binary parameters of objects, but on the mass-accretion process for each outburst.

  16. Outburst of a WZ Sge-type dwarf nova, AL Com in 2007

    OpenAIRE

    M. Uemura(Hiroshima Astrophysical Science Center, Hiroshima University, Japan); Arai, A.; Sasada, M.; Schmeer, P.; Miller, I.; Ohsugi, T.; Yamashita, T; Kawabata, K. S.; Isogai, M.; Sato, S.; Kino, M.

    2008-01-01

    We report photometric observations of AL Com during its rare outburst in 2007. The light curve is reminiscent of its past superoutbursts in 1995 and 2001, except for the rebrightening phase after the main superoutburst. During the rebrightening phase in 2007, we found clear modulations between V=16.2-15.2. In conjunction with the lack of prominent superhumps in our time-series observations, the modulations can most naturally be interpreted as repetitive short rebrightenings with a cycle of 1-...

  17. Swift X-ray and UV monitoring of the Classical Nova V458 Vul (Nova Vul 2007)

    CERN Document Server

    Ness, J -U; Beardmore, A P; Boyd, D; Bode, M F; Brady, S; Evans, P A; Gänsicke, B T; Kitamoto, S; Knigge, C; Miller, I; Osborne, J P; Page, K L; Rodríguez-Gil, P; Schwarz, G; Staels, B; Steeghs, D; Takei, D; Tsujimoto, M; Wesson, R; Zijlstra, A

    2009-01-01

    We describe the highly variable X-ray and UV emission of V458 Vul (Nova Vul 2007), observed by Swift between 1 and 422 days after outburst. Initially bright only in the UV, V458 Vul became a variable hard X-ray source due to optically thin thermal emission at kT=0.64 keV with an X-ray band unabsorbed luminosity of 2.3x10^{34} erg s^{-1} during days 71-140. The X-ray spectrum at this time requires a low Fe abundance (0.2^{+0.3}_{-0.1} solar), consistent with a Suzaku measurement around the same time. On day 315 we find a new X-ray spectral component which can be described by a blackbody with temperature of kT=23^{+9}_{-5} eV, while the previous hard X-ray component has declined by a factor of 3.8. The spectrum of this soft X-ray component resembles those typically seen in the class of supersoft sources (SSS) which suggests that the nova ejecta were starting to clear and/or that the WD photosphere is shrinking to the point at which its thermal emission reaches into the X-ray band. We find a high degree of varia...

  18. Precursor outbursts and superoutbursts in the SU UMa-type dwarf nova NN Camelopardalis

    CERN Document Server

    Shears, Jeremy; Julian, William Mack; Krajci, Tom; Kudzej, Igor; Miller, Ian; Morelle, Etienne; Sabo, Richard; Solovyova, Irina; Staels, Bart; Vanmunster, Tonny

    2010-01-01

    We report photometry of three outbursts of NN Cam in 2007, 2008 and 2009. The 2007 event started with a normal outburst, lasting about 4 days, which was a precursor to a superoutburst lasting at least 13 days. Both the precursor and the superoutburst had an amplitude of 4.9 mag above mean quiescence. Superhumps with a maximum peak-to-peak amplitude of 0.22 mag were detected during the superoutburst with a mean superhump period Psh = 0.07385(56) d. Psh decreased continuously with dPsh /dt = -1.72(23) x 10-3. We used our measurement to confirm that the shorter of two possible values of Porb reported by another researcher is the correct one, Porb = 0.0717 d. The 2008 outburst was rather poorly observed, although we present evidence that this too may have been a superoutburst. The 2009 event was also a superoutburst, with Psh = 0.07414(44) d, but we could find no evidence for a precursor. From the 2007 and 2009 data, we report a superhump period excess of epsilon = 0.030(8) to 0.034(6), which is typical for SU UM...

  19. Pre-nova X-ray observations of V2491 Cyg (Nova Cyg 2008b)

    CERN Document Server

    Ibarra, A; Osborne, J P; Page, K; Ness, J U; Saxton, R D; Baumgartner, W; Beckmann, V; Bode, M F; Hernanz, M; Mukai, K; Orio, M; Sala, G; Starrfield, S; Wynn, G A

    2009-01-01

    Classical novae are phenomena caused by explosive hydrogen burning on an accreting white dwarf. So far, only one classical nova has been identified in X-rays before the actual optical outburst occurred (V2487 Oph). The recently discovered nova, V2491 Cyg, is one of the fastest (He/N) novae observed so far. Using archival ROSAT, XMM-Newton and Swift data, we show that V2491 Cyg was a persistent X-ray source during its quiescent time before the optical outburst. We present the X-ray spectral characteristics and derive X-ray fluxes. The pre-outburst X-ray emission is variable, and at least in one observation it shows a very soft X-ray source.

  20. CNO abundances and hydrodynamic models of the nova outburst. III - 0.5 solar mass models with enhanced carbon, oxygen, and nitrogen

    Science.gov (United States)

    Starrfield, S.; Sparks, W. M.; Truran, J. W.

    1974-01-01

    Consideration of the evolution of thermonuclear runaways in the hydrogen-rich envelopes of 0.5 solar mass carbon-oxygen white dwarfs. The larger radii of these stars, compared with the 1.00 solar mass white dwarfs, results in a lesser degree of degeneracy at the same depth in the star. Four models of luminosity with .00355 solar luminosity, differing only in the initial abundances of C-12, N-14, and O-16, are presented. The degree of enhancement required to produce mass ejection, and thereby a nova-type outburst, is greater than for the 1.00 solar mass model. Nevertheless, the evolution of the 0.5 solar mass model that ejected material is very similar to that of the 1.00 solar mass models, and it also ejects significant amounts of C-13, N-15, and O-17 into the interstellar medium. The 0.5 solar mass outburst is considerably less intense than the 1.00 solar mass outburst (even under optimum conditions), and this lower mass behavior is interpreted as associated with the observed outburst of the slowest novae.

  1. THE 7.1 HR X-RAY-ULTRAVIOLET-NEAR-INFRARED PERIOD OF THE {gamma}-RAY CLASSICAL NOVA MONOCEROTIS 2012

    Energy Technology Data Exchange (ETDEWEB)

    Page, K. L.; Osborne, J. P.; Beardmore, A. P. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Wagner, R. M. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Shore, S. N. [Dipartimento di Fisica ' ' Enrico Fermi' ' , Universita di Pisa, and INFN - Sezione di Pisa (Italy); Starrfield, S. [School of Earth and Space Exploration, P.O. Box 871404, Arizona State University, Tempe, AZ 85287-1404 (United States); Woodward, C. E., E-mail: klp5@leicester.ac.uk [Minnesota Institute for Astrophysics, U. Minnesota, 116 Church St, SE Minneapolis, MN 55455 (United States)

    2013-05-10

    Nova Monocerotis 2012 is the third {gamma}-ray transient identified with a thermonuclear runaway on a white dwarf, that is, a nova event. Swift monitoring has revealed the distinct evolution of the harder and super-soft X-ray spectral components, while Swift-UV and V- and I-band photometry show a gradual decline with subtle changes of slope. During the super-soft emission phase, a coherent 7.1 hr modulation was found in the soft X-ray, UV, optical, and near-IR data, varying in phase across all wavebands. Assuming this period to be orbital, the system has a near-main-sequence secondary, with little appreciable stellar wind. This distinguishes it from the first GeV nova, V407 Cyg, where the {gamma}-rays were proposed to form through shock-accelerated particles as the ejecta interacted with the red giant wind. We favor a model in which the {gamma}-rays arise from the shock of the ejecta with material close to the white dwarf in the orbital plane. This suggests that classical novae may commonly be GeV sources. We ascribe the orbital modulation to a raised section of an accretion disk passing through the line of sight, periodically blocking and reflecting much of the emission. The disk must therefore have reformed by day 150 after outburst.

  2. SWIFT X-RAY AND ULTRAVIOLET MONITORING OF THE CLASSICAL NOVA V458 VUL (NOVA VUL 2007)

    International Nuclear Information System (INIS)

    We describe the highly variable X-ray and UV emission of V458 Vul (Nova Vul 2007), observed by Swift between 1 and 422 days after outburst. Initially bright only in the UV, V458 Vul became a variable hard X-ray source due to optically thin thermal emission at kT = 0.64 keV with an X-ray band unabsorbed luminosity of 2.3 x 1034 erg s-1 during days 71-140. The X-ray spectrum at this time requires a low Fe abundance (0.2+0.3-0.1 solar), consistent with a Suzaku measurement around the same time. On day 315 we find a new X-ray spectral component which can be described by a blackbody with temperature of kT = 23+9-5 eV, while the previous hard X-ray component has declined by a factor of 3.8. The spectrum of this soft X-ray component resembles those typically seen in the class of supersoft sources (SSS) which suggests that the nova ejecta were starting to clear and/or that the white dwarf photosphere is shrinking to the point at which its thermal emission reaches into the X-ray band. We find a high degree of variability in the soft component with a flare rising by an order of magnitude in count rate in 0.2 days. In the following observations on days 342.4-383.6, the soft component was not seen, only to emerge again on day 397. The hard component continued to evolve, and we found an anticorrelation between the hard X-ray emission and the UV emission, yielding a Spearman rank probability of 97%. After day 397, the hard component was still present, was variable, and continued to fade at an extremely slow rate but could not be analyzed owing to pile-up contamination from the bright SSS component.

  3. On the Raman O VI and related lines in classical novae

    CERN Document Server

    Shore, Steven N; Scaringi, Simone; van Winckel, Hans

    2014-01-01

    We critically examine the recent claimed detection of Raman scattered O VI at around 6830\\AA\\ in the iron curtain stage spectra of the classical CO nova V339 Del. The observed line variations are compatible in profile and timing of emission line strength with an excited state transition of neutral carbon. Line formation in classical nova ejecta is physically very different from that in symbiotic binaries, in which the O VI emission line is formed within the wind of the companion red giant at low differential velocity. The ejecta velocity and density structure prevent the scattering from producing analogous features. There might , however, be a broadband spectropolarimetric signature of the Raman process and also Rayleigh scattering at some stage in the expansion. We show that the neutral carbon spectrum, hitherto under-exploited for novae, is especially useful as a probe of the structure of the ejecta during the early, optically thick stages of the expansion

  4. The January 2015 outburst of a red nova in M31

    CERN Document Server

    Kurtenkov, Alexander; Tomov, Toma; Barsukova, Elena A; Fabrika, Sergei; Vida, Krisztián; Hornoch, Kamil; Ovcharov, Evgeni P; Goranskij, Vitaly P; Valeev, Azamat F; Molnár, László; Sárneczky, Krisztián; Kostov, Andon; Nedialkov, Petko; Valenti, Stefano; Geier, Stefan; Wiersema, Klaas; Henze, Martin; Shafter, Allen W; Dimitrova, Rosa Victoria Muñoz; Popov, Vasil N; Stritzinger, Maximilian

    2015-01-01

    M31N 2015-01a (or M31LRN 2015) is a red nova that erupted in January 2015 -- the first event of this kind observed in M31 since 1988. Very few similar events have been confirmed as of 2015. Most of them are considered to be products of stellar mergers. Results of an extensive optical monitoring of the transient in the period January-March 2015 are presented. Eight optical telescopes were used for imaging. Spectra were obtained on BTA, GTC and the Rozhen 2m telescope. We present a highly accurate 70 d lightcurve and astrometry with a 0.05" uncertainty. The color indices reached a minimum 2-3 d before peak brightness and rapidly increased afterwards. The spectral type changed from F5I to F0I in 6 d before the maximum and then to K3I in the next 30 d. The luminosity of the transient was estimated to $8.7^{+3.3}_{-2.2}\\times10^{5}L_{\\odot}$ during the optical maximum. Both the photometric and the spectroscopic results confirm that the object is a red nova, similar to V838 Monocerotis.

  5. Modelling the Soft X-Ray and EUV Emission in Classical Novae: EUVE and ROSAT Observations of V1974 Cygni

    Science.gov (United States)

    Stringfellow, Guy S.; Bowyer, Stuart

    1996-01-01

    We have conducted an extensive analysis of the observability of Classical Novae with the EUVE Lex/B and Al/Ti/C detectors. Predicted count rates have been computed using optically thin, isothermal plasma models for solar and metal-rich compositions, and hot ONeMg white dwarf model atmospheres. We find EUVE to be quite sensitive to both the EUV and soft X-ray emission emitted by the underlying hot white dwarf during novae outbursts, except for the coolest temperatures with very high intervening hydrogen column density. These results are used to interpret the emission detected during the EUVE all-sky survey of Nova Cygni 1992 (approx. = V1974 Cyg), 279-290 days after visual maximum. We find the best fit to the observed emission from V1974 Cyg arises from a hot ONeMg white dwarf with surface temperature approx. 4 x l0(exp 5) K and a mas of approx. 1.2 solar mass, and derive an interstellar hydrogen column density of approx. 3 x 10(exp 21)/sq cm. Virtually all this emission arises from supersoft X-rays rather than the EUV. We also report the detection of V1974 Cyg with the EUVE Deep Survey detector at 549 days after visual maximum. This observation is compatible with the above properties, indicating that the mechanism responsible for the soft X-ray emission, connected with the underlying white dwarf, had not yet entirely turned off. We also present analysis of a ROSAT PSPC observation which is contemporaneous with the EUVE survey observations; this independently confirms the high column density we derived from the EUVE survey observation. Light curves for the EUVE and ROSAT observations are presented. Statistical tests for variability show that all of these observations are indeed highly variable over various time scales. The EUVE survey data shows one day variations, the EUVE DS data show approx. 30 minute fluctuations, while the ROSAT data vary rapidly on time scales of seconds. The EUVE data shows no periodic variability on any time scale. The implications of the

  6. Three-dimensional simulations of turbulent convective mixing in ONe and CO classical nova explosions

    CERN Document Server

    Casanova, Jordi; Garcia-Berro, Enrique; Shore, Steven N

    2016-01-01

    Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in binary systems. The material piles up under degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope heats the material up to peak temperatures about 100 - 400 MK. During these events, about 10-3 - 10-7 Msun, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, Al) are ejected into the interstellar medium. To account for the gross observational properties of classical novae (in particular, the large concentrations of metals spectroscopically inferred in the ejecta), models require mixing between the (solar-like) material transferred from the secondary and the outermost layers (CO- or ONe-rich) of the underlying white dwarf. Recent multidimensional simulations have demonstrated that Kelvin-Helmholtz instabilities can naturally produce self-enrichment of the accreted envelope with material from the...

  7. Nova Aquila 1919: a nova after all?

    CERN Document Server

    Lau, Herbert H B; Liu, X W

    2010-01-01

    Nova 1919 Aquila is today widely assumed to have been the result of a final helium shell flash occurring on a single post-asymptotic giant branch star. The fact that the outbursting star is in the middle of an old planetary nebula and that the ejecta associated with the outburst is hydrogen deficient supports this diagnosis. However, the material ejected during that outburst is also extremely neon rich, suggesting that it derives from an oxygen-neon-magnesium star, as is the case in the so-called neon novae. We have therefore attempted to construct a scenario that explains all the observations of the nebula and its central star, including the ejecta abundances. We find two scenarios that have the potential to explain the observations, although neither is a perfect match. The first scenario invokes the merger of a main sequence star and a massive oxygen-neon-magnesium white dwarf. The second invokes an oxygen-neon-magnesium classical nova that takes place shortly after a final helium shell flash. The main draw...

  8. The hunt for old novae

    CERN Document Server

    Tappert, C; Schmidtobreick, L; Ederoclite, A

    2013-01-01

    We inform on the progress of our on-going project to identify and classify old classical novae, using deep UBVR photometry and subsequent spectroscopy for a proper candidate confirmation, and time-resolved observations in order to find the orbital period and other physical properties of the identified old novae. This way, we have already increased the number of confirmed southern and equatorial post-novae from 33 to 50, and determined new orbital periods of eight objects. As an example, we summarise the results on V728 Sco (Nova Sco 1862) which we found to be an eclipsing system with a 3.32 h orbital period, displaying high and low states similar to dwarf-nova outbursts. Analysis of the low-state eclipse indicates the presence of a small hot inner disc around the white dwarf component.

  9. DISCOVERY OF X-RAY EMISSION IN THE OLD CLASSICAL NOVA DK LACERTAE

    International Nuclear Information System (INIS)

    We report the discovery of X-ray emission at the position of the old classical nova DK Lacertae using the Swift satellite. Three observations were conducted using the X-Ray Telescope 62 years after the discovery of the nova, yielding 46 source signals in an exposure time of 4.8 ks. A background-subtracted count rate was 9 ± 2 × 10–3 counts s–1, corresponding to a detection significance level of 5σ. The X-ray spectrum was characterized by a continuum extending up to about 7 keV, which can be modeled by a power-law component with a photon index of 1.4-5.6, or by a thermal bremsstrahlung component with a temperature of 0.7-13.3 keV, convolved with interstellar absorption with an equivalent hydrogen column density of 0.3-2.4 × 1022 cm–2. Assuming a distance of 3900 pc to the source, the luminosity was 1032-1034 erg s–1 in the 0.3-10 keV energy band. The origin of X-rays is considered to be either mass accretion on the white dwarf or adiabatic shocks in nova ejecta, with the former appearing much more likely. In either case, DK Lacertae represents a rare addition to the exclusive club of X-ray emitting old novae.

  10. Fermi LAT Gamma-ray Detections of Classical Novae V1369 Centauri 2013 and V5668 Sagittarii 2015

    CERN Document Server

    Cheung, C C; Shore, S N; Stawarz, L; Corbet, R H D; Knodlseder, J; Starrfield, S; Wood, D L; Desiante, R; Longo, F; Pivato, G; Wood, K S

    2016-01-01

    We report the Fermi Large Area Telescope (LAT) detections of high-energy (>100 MeV) gamma-ray emission from two recent optically bright classical novae, V1369 Centauri 2013 and V5668 Sagittarii 2015. At early times, Fermi target-of-opportunity observations prompted by their optical discoveries provided enhanced LAT exposure that enabled the detections of gamma-ray onsets beginning ~2 days after their first optical peaks. Significant gamma-ray emission was found extending to 39-55 days after their initial LAT detections, with systematically fainter and longer duration emission compared to previous gamma-ray detected classical novae. These novae were distinguished by multiple bright optical peaks that encompassed the timespans of the observed gamma rays. The gamma-ray light curves and spectra of the two novae are presented along with representative hadronic and leptonic models, and comparisons to other novae detected by the LAT are discussed.

  11. Swift observations of the 2006 outburst of the recurrent nova RS Ophiuchi: II. 1D hydrodynamical models of wind driven shocks

    CERN Document Server

    Vaytet, N M H; Bode, M F

    2007-01-01

    Following the early Swift X-ray observations of the latest outburst of the recurrent nova RS Ophiuchi in February 2006 (Paper I), we present new 1D hydrodynamical models of the system which take into account all three phases of the remnant evolution. The models suggest a novel way of modelling the system by treating the outburst as a sudden increase then decrease in wind mass-loss rate and velocity. The differences between this wind model and previous Primakoff-type simulations are described. A more complex structure, even in 1D, is revealed through the presence of both forward and reverse shocks, with a separating contact discontinuity. The effects of radiative cooling are investigated and key outburst parameters such as mass-loss rate, ejecta velocity and mass are varied. The shock velocities as a function of time are compared to the ones derived in Paper I. We show how the manner in which the matter is ejected controls the evolution of the shock and that for a well-cooled remnant, the shock deceleration ra...

  12. SOAR observations of the high-viscosity accretion disc of the dwarf nova V4140 Sagitarii in quiescence and in outburst

    CERN Document Server

    Baptista, Raymundo; Oliveira, Alexandre S

    2016-01-01

    We report the analysis of 22 B-band light curves of the dwarf nova V4140 Sgr obtained with SOI/SOAR during two nights along the decline of a superoutburst in 2006 Sep 12-24 and in quiescence over 50 days following the superoutburst. Three-dimensional eclipse mapping of the outburst light curves indicates that the accretion disc is elliptical (eccentricity e=0.13) and that superhump maximum occurs when the mass donor star is aligned with the bulge of the elliptical disc. The accretion disc is geometrically thin both in outburst and in quiescence; it fills the primary Roche lobe in outburst and shrinks to about half this size in quiescence. The stability of the eclipse shape, width and depth along quiescence and the derived disc surface brightness distribution indicate that the quiescent accretion disc is in a high-viscosity, steady-state. Flickering mapping of the quiescent data reveal that the low-frequency flickering arises from an azimuthally-extended stream-disc impact region at disc rim and from the inner...

  13. Detectability of gamma-ray emission from classical novae with Swift/BAT

    OpenAIRE

    Senziani, F.; Skinner, G. K.; Jean, P; Hernanz, M.

    2008-01-01

    Classical novae are expected to emit gamma rays during their explosions. The most important contribution to the early gamma-ray emission comes from the annihilation with electrons of the positrons generated by the decay of 13N and 18F. The photons are expected to be down-scattered to a few tens of keV, and the emission is predicted to occur some days before the visual discovery and to last ~2 days. Despite a number of attempts, no positive detections of such emission have been made, due to la...

  14. Classical novae and type I X-ray bursts: Challenges for the 21st century

    International Nuclear Information System (INIS)

    Classical nova explosions and type I X-ray bursts are the most frequent types of thermonuclear stellar explosions in the Galaxy. Both phenomena arise from thermonuclear ignition in the envelopes of accreting compact objects in close binary star systems. Detailed observations of these events have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. We discuss observational features of these phenomena and theoretical efforts to better understand the energy production and nucleosynthesis in these explosions. We also examine and summarize studies directed at identifying nuclear physics quantities with uncertainties that significantly affect model predictions

  15. Spectral evolution of the X-ray nova XTE J1859+226 during its outburst observed by BeppoSAX and RXTE

    CERN Document Server

    Farinelli, R; Shaposhnikov, N; Frontera, F; Masetti, N; Palazzi, E; Landi, R; Lombardi, C; Orlandini, M; Brocksopp, C

    2012-01-01

    We report results of an extensive analysis of the X-ray nova XTE J1859+226 observed with BeppoSAX and RXTE during its 1999 outburst. We modelled the source spectrum with a multicolour blackbody-like feature plus the generic Comptonization model BMC which has the advantage of providing spectral description of the emitted-radiation properties without assumptions on the underlying physical process. The multicolour component is attributed to the geometrically thin accretion disk, while the Comptonization spectrum is claimed to originate in the innermost sub-Keplerian region of the system (transition layer). We find that XTE J1859+226 covers all the spectral states typical of black-hole sources during its evolution across the outburst, however during the very high state, when the disk contribution to the total luminosity is more than 70% and the root mean square variability > 5%, the high-energy photon index is closer to a hard state value (Gamma ~ 1.8). The BMC normalization and photon index Gamma well correlate ...

  16. Rossi X-Ray Timing Explorer Observations of an Outburst of Recurrent X-Ray Nova GS 1354-644

    International Nuclear Information System (INIS)

    We present the results of Rossi X-Ray Timing Explorer (RXTE) observations of GS 1354-644 during a modest outburst in 1997-1998. The source is one of a handful of black hole X-ray transients that are confirmed to be recurrent in X-rays. A 1987 outburst of the same source observed by Ginga was much brighter and showed a high/soft spectral state. In contrast, the 1997-1998 outburst showed a low/hard spectral state. Both states are typical of black hole binaries. The RXTE All-Sky Monitor observed an outburst duration of 150-200 days. PCA and HEXTE observations covered ∼70 days near the maximum of the light curve and during the flux decline. Throughout the observations, the spectrum can be approximated by Compton upscattering of soft photons by energetic electrons. The hot electron cloud has a temperature kT∼30 keV and optical depth τ∼4-5. To fit the data well, an additional iron fluorescent line and reflection component are required, which indicates the presence of optically thick cool material, most probably in the outer part of the accretion disk. Dramatic fast variability was observed and has been analyzed in the context of a shot noise model. The spectrum appeared to be softest at the peaks of the shot noise variability. The shape of the power spectrum was typical for black hole systems in a low/hard state. We note a qualitative difference in the shape of the dependence of fractional variability on energy when we compare systems with black holes and with neutron stars. Since it is difficult to discriminate these systems on spectral grounds, at least in their low/hard states, this new difference might be important. (c) 2000 The American Astronomical Society

  17. The Onset of a Common Envelope Episode: Lessons from the Remarkable M31 2015 Luminous Red Nova Outburst

    CERN Document Server

    MacLeod, Morgan; Ramirez-Ruiz, Enrico; Grindlay, Jonathan; Batta, Aldo; Montes, Gabriela

    2016-01-01

    This paper investigates the recent transient M31LRN 2015 in the Andromeda galaxy. We analyze published optical photometry and spectroscopy along with a Hubble Space Telescope detection of the color and magnitude of the pre-outburst source. Using these data, we determine that the transient outburst is caused by dynamically driven ejecta at the onset of a common envelope episode, which eventually leads to the complete merger of a binary system. Just prior to merger, we find that the primary star is a $3-5.5 M_\\odot$ sub-giant branch star with radius of $30-40R_\\odot$. Its position in the color-magnitude diagram shows that it is growing in radius to eventually engulf its companion. By matching the properties of the binary system to the transient outburst, we show that the light curve contains two components: first $10^{-2} M_\\odot$ of fast ejecta driven by shocks at contact in between the primary and secondary, and later, $0.2 M_\\odot$ of slower ejecta as the secondary becomes more deeply engulfed within the pri...

  18. Recurrent nova M31N 2008-12a: the 2015 outburst detected in X-rays with Swift XRT

    Science.gov (United States)

    Henze, M.; Darnley, M. J.; Shafter, A. W.; Kato, M.; Hachisu, I.; Bode, M. F.; Ness, J.-U.; Osborne, J. P.; Kennea, J. A.; Gehrels, N.

    2015-09-01

    In ATel #7964 we reported the discovery of the 2015 eruption of the recurrent nova M31N 2008-12a on 2015-08-28.55 UT. Comprehensive multi-wavelength studies of previous eruptions were published by Darnley et al.

  19. On the Galactic Nova Progenitor Population

    CERN Document Server

    Darnley, M J; Harman, D J; Hounsell, R A; Munari, U; Ribeiro, V A R M; Surina, F; Williams, R P; Williams, S C

    2013-01-01

    Of the 350 or more known Galactic classical novae, only a handful of them, the recurrent novae, have been observed in outburst more than once. At least eight of these recurrents are known to harbour evolved secondary stars, rather than the main sequence secondaries typical in classical novae. Here we present a selection of the work and rationale that led to the proposal of a new nova classification scheme based not on the outburst properties but on the nature of the quiescent system. Also outlined are the results of a photometric survey of a sample of quiescent Galactic novae, showing that the evolutionary state of the secondary can be easily determined and leading to a number of predictions. We discuss the implications of these results, including their relevance to extragalactic work and the proposed link to type Ia supernovae. We also present a summary of the work using the SMEI instrument to produce exquisite nova light-curves and confirmation of the pre-maximum halt.

  20. The Detailed Photometric and Spectroscopic Study of the 2011 Outburst of the Recurrent Nova T Pyxidis from 0.8 to 250 Days after Discovery

    CERN Document Server

    Surina, F; Bode, M F; Darnley, M J; Harman, D J; Walter, F M

    2014-01-01

    We investigated the optical lightcurve of T Pyx during its 2011 outburst by compiling a database of SMEI and AAVSO observations. The SMEI lightcurve, providing unprecedented detail covering 1.5-49d post-discovery, was divided into four phases based on the idealised CN optical lightcurve; the initial rise (1.5-3.3d), the pre-maximum halt (3.3-13.3d), the final rise (14.7-27.9d), and the early decline (27.9d-). The SMEI lightcurve contains a strongly detected period of 1.44+/-0.05d during the pre-maximum phase. These oscillations resemble those found in TNR models arising from instabilities in the expanding envelope. No spectral variation mirroring the lightcurve periodicity was found. A marked dip at 22-24d just before maximum light (27.9d) may represent the same phenomenon seen in novae observed by SMEI. Spectra from the Liverpool Telescope and SMARTS 1.5m were obtained from 0.8-80.7 and 155.1-249.9d, covering the major phases of development. A distinct high velocity ejection phase was evident during the earl...

  1. The spectroscopic evolution of the symbiotic-like recurrent nova V407 Cygni during its 2010 outburst. I. The shock and its evolution

    CERN Document Server

    Shore, S N; Augusteijn, T; Liimets, T; Page, K L; Osborne, J P; Beardmore, A P; Koubsky, P; Šlechta, M; Votruba, V

    2010-01-01

    On 2010 Mar 10, V407 Cyg was discovered in outburst, eventually reaching V< 8 and detected by Fermi. Using medium and high resolution ground-based optical spectra, visual and Swift UV photometry, and Swift X-ray spectrophotometry, we describe the behavior of the high-velocity profile evolution for this nova during its first three months. The peak of the X-ray emission occurred at about day 40 with a broad maximum and decline after day 50. The main changes in the optical spectrum began at around that time. The He II 4686A line first appeared between days 7 and 14 and initially displayed a broad, symmetric profile that is characteristic of all species before day 60. Low-excitation lines remained comparatively narrow, with v(rad,max) of order 200-400 km/s. They were systematically more symmetric than lines such as [Ca V], [Fe VII], [Fe X], and He II, all of which showed a sequence of profile changes going from symmetric to a blue wing similar to that of the low ionization species but with a red wing extended ...

  2. Near Infrared studies during maximum and early decline of Nova Cephei 2014 and Nova Scorpii 2015

    CERN Document Server

    Srivastava, Mudit K; Banerjee, D P K; Sand, D

    2015-01-01

    We present multi-epoch near-infrared photo-spectroscopic observations of Nova Cephei 2014 and Nova Scorpii 2015, discovered in outburst on 2014 March 8.79 UT and 2015 February 11.84 UT respectively. Nova Cep 2014 shows the conventional NIR characteristics of a Fe II class nova characterized by strong CI, HI and O I lines, whereas Nova Sco 2015 is shown to belong to the He/N class with strong He I, HI and OI emission lines. The highlight of the results consists in demonstrating that Nova Sco 2015 is a symbiotic system containing a giant secondary. Leaving aside the T CrB class of recurrent novae, all of which have giant donors, Nova Sco 2015 is shown to be only the third classical nova to be found with a giant secondary. The evidence for the symbiotic nature is three-fold; first is the presence of a strong decelerative shock accompanying the passage of the nova's ejecta through the giant's wind, second is the H$\\alpha$ excess seen from the system and third is the spectral energy distribution of the secondary i...

  3. Differences in the fast optical variability of the dwarf nova V1504 Cyg between quiescence and outbursts detected in Kepler data and simulations of the rms-flux relations

    CERN Document Server

    Dobrotka, A

    2015-01-01

    An optical light curve of SU UMa type dwarf nova V1504 Cyg taken by Kepler was analysed in order to study fast optical variability (flickering). We calculated power density spectra and rms-flux relations for two different stages of activity, i.e. quiescence and regular outbursts. A multicomponent power density spectrum with two break frequencies was found during both activity stages. The rms-flux relation is obvious only in the quiescent data. However, while the collection of all outburst data do not show this variability, every individual outburst does show it in the majority of cases keeping the rms value approximately in the same interval. Furthermore, the same analysis was performed for light curve subsamples taken from the beginning, middle and the end of the supercycle both for quiescence and regular outbursts. Every light curve subsample shows the same multicomponent power density spectrum. The stability of the break frequencies over the supercycle can be confirmed for all frequencies except for the hi...

  4. The 7.1 hour X-ray-UV-NIR period of the gamma-ray classical Nova Monocerotis 2012

    CERN Document Server

    Page, K L; Wagner, R M; Beardmore, A P; Shore, S N; Starrfield, S; Woodward, C E

    2013-01-01

    Nova Mon 2012 is the third gamma-ray transient identified with a thermonuclear runaway on a white dwarf, that is, a nova event. Swift monitoring has revealed the distinct evolution of the harder and super-soft X-ray spectral components, while Swift-UV and V and I-band photometry show a gradual decline with subtle changes of slope. During the super-soft emission phase, a coherent 7.1 hr modulation was found in the soft X-ray, UV, optical and near-IR data, varying in phase across all wavebands. Assuming this period to be orbital, the system has a near-main sequence secondary, with little appreciable stellar wind. This distinguishes it from the first GeV nova, V407 Cyg, where the gamma-rays were proposed to form through shock-accelerated particles as the ejecta interacted with the red giant wind. We favor a model in which the gamma-rays arise from the shock of the ejecta with material close to the white dwarf in the orbital plane. This suggests that classical novae may commonly be GeV sources. We ascribe the orb...

  5. PHASE-RESOLVED INFRARED SPECTROSCOPY AND PHOTOMETRY OF V1500 CYGNI, AND A SEARCH FOR SIMILAR OLD CLASSICAL NOVAE

    International Nuclear Information System (INIS)

    We present phase-resolved near-infrared photometry and spectroscopy of the classical nova (CN) V1500 Cyg to explore whether cyclotron emission is present in this system. While the spectroscopy do not indicate the presence of discrete cyclotron harmonic emission, the light curves suggest that a sizable fraction of its near-infrared fluxes are due to this component. The light curves of V1500 Cyg appear to remain dominated by emission from the heated face of the secondary star in this system. We have used infrared spectroscopy and photometry to search for other potential magnetic systems among old CNe. We have found that the infrared light curves of V1974 Cyg superficially resemble those of V1500 Cyg, suggesting a highly irradiated companion. The old novae V446 Her and QV Vul have light curves with large amplitude variations like those seen in polars, suggesting they might have magnetic primaries. We extract photometry for 79 old novae from the Two Micron All Sky Survey Point Source Catalog and use those data to derive the mean, un-reddened infrared colors of quiescent novae. We also extract WISE data for these objects and find that 45 of them were detected. Surprisingly, a number of these systems were detected in the WISE 22 μm band. While two of those objects produced significant dust shells (V705 Cas and V445 Pup), the others did not. It appears that line emission from their ionized ejected shells is the most likely explanation for those detections

  6. The spectroscopic evolution of novae in the bulge of M31 and a search for their possible origin in the M31 globular cluster system

    Science.gov (United States)

    Tomaney, Austin Bede

    Results are presented from a three year (1987 to 1989) spectroscopic and photometric survey of novae in M3l's bulge, the first comprehensive study of novae outside the Galactic and Magellanic Cloud systems. Nine novae were detected and monitored and their spectra cover a range of outburst states from early decline to the early nebular phases. Broad agreement in spectral morphology and evolution is found with Galactic novae. Since Galactic novae are mainly disk objects, this indicates that novae outburst properties are not critically dependent on the metallicity of the progenitor population. However, in this sample, and in a sample of four M31 nova spectra taken in 1983, no fast, violent outbursts frequently associated with nova systems containing ONeMg white dwarfs were found, suggestive of a systematic difference between the observed proportion of such outbursts between Galactic and M31 bulge novae. Three novae in the sample were observed on succeeding nights during the transition phase of their evolution. Extraordinary variations in some nightly line strengths, particularly the N III lines, were discovered. It is argued that this variability reflects the deposition of drag energy by the secondary star during the common envelope phase of nova evolution and is indicative of a key phase in mass loss from nova systems. Observations include the spectroscopic coverage of an extremely slow nova from 1987 to l990, during the object's evolution in the nebula phase. This provided a unique opportunity to make the first detailed comparison of the evolution and properties of an extra galactic nova with those in our own Galaxy. The roughly solar abundances obtained are typical of similar slow Galactic novae. Further observations are also presented of a unique outburst in 1988 that was independently discovered and reported by Rich et al. These data confirm the inferences of other observers that the outburst differed markedly from that of a typical classical nova. Finally an

  7. Search for Soft X-ray Flashes at Fireball Phase of Classical/Recurrent Novae using MAXI/GSC data

    CERN Document Server

    Morii, Mikio; Mihara, Tatehiro; Matsuoka, Masaru; Kawai, Nobuyuki

    2016-01-01

    We searched for precursive soft X-ray flashes (SXFs) associated with optically-discovered classical or recurrent novae in the data of five-years all-sky observations with Gas Slit Camera (GSC) of the Monitor of All-sky X-ray Image (MAXI). We first developed a tool to measure fluxes of point sources by fitting the event distribution with the model that incorporates the point-spread function (PSF-fit) to minimize the potential contamination from nearby sources. Then we applied the PSF-fit tool to 40 classical/recurrent novae that were discovered in optical observations from 2009 August to 2014 August. We found no precursive SXFs with significance above $3 \\sigma$ level in the energy range of 2$-$4 keV between $t_{d}-10$d and $t_{d}$, where $t_{d}$ is the date when each nova was discovered. We obtained the upper limits for the bolometric luminosity of SXFs, and compared them with the theoretical prediction and that observed for MAXI J0158$-$744. This result could constrain the population of massive white dwarfs ...

  8. Discovery of Irradiation Induced Variations in the Light Curve of the Classical Nova Cygni 2001 No.2 (V2275 Cyg)

    CERN Document Server

    Balman, S; Retter, A; Saygac, T; Esenoglu, H

    2004-01-01

    We present the CCD photometry, light curve and time series analysis of the classical nova V2275 Cyg (N Cyg 2001 No.2). The source was observed for 14 nights in total using an R filter in 2002 and 2003 with the 1.5 m Russian-Turkish joint telescope (RTT150) at the TUBITAK (The Scientific and Technical Research Council of Turkey) National Observatory in Antalya Turkey, as part of a large program on the CCD photometry of Cataclysmic Variables (CVs). We report the detection of two distinct periodicities in the light curve of the nova : a) P_1=0.31449(15) d -- 7.6 h, b) P_2=0.017079(17) d -- 24.6 min. The first period is evident in both 2002 and 2003 whereas the second period is only detected in the 2003 data set. We interpret the first period as the orbital period of the system and attribute the orbital variations to aspect changes of the secondary irradiated by the hot WD. We suggest that the nova was a Super Soft X-ray source in 2002 and, perhaps, in 2003. The second period could be a QPO originating from the o...

  9. Supersoft X-rays reveal a classical nova in the M 31 globular cluster Bol 126

    Czech Academy of Sciences Publication Activity Database

    Henze, M.; Pietsch, W.; Haberl, F.; Della Valle, M.; Riffeser, A.; Salla, G.; Hatzidimitriou, D.; Hofmann, F.; Hartmann, D.H.; Koppenhoefer, J.; Seitz, S.; Williams, G.; Hornoch, Kamil; Itagaki, K.; Kabashima, F.; Nishiyama, K.; Xing, G.; Lee, C.H.; Magnier, E.; Chambers, K.

    2013-01-01

    Roč. 549, January (2013), A120/1-A120/15. ISSN 0004-6361 Institutional support: RVO:67985815 Keywords : galaxies individual M 31 * novae * cataclysmic variables Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.479, year: 2013

  10. Discovery and Spectroscopic Classification of iPTFemh as a Classical Nova in M31

    Science.gov (United States)

    Chinetti, K.; Darnley, M. J.; Blagorodnova, N.; Neill, J. D.; Williams, S. C.

    2016-08-01

    We report the discovery of nova candidate iPTFemh with the CFH12k instrument taken on 2016 Aug 01.45 UT on the Palomar 48-in telescope. The new object is located at RA 00:43:57.77, DEC +41:34:52.6 (J2000.0), and was not detected in images taken 2016 July 26.49.

  11. Optical Spectroscopy of the Classical Novae V339 Del (2013) and V5668 Sgr (2015 No. 2)

    Science.gov (United States)

    Wagner, R. Mark; Woodward, Charles E.; Starrfield, Sumner; Ilyin, Ilya; Strassmeier, Klaus G.; Page, Kim; Osborne, Julian P.; Beardmore, Andrew P.

    2016-01-01

    We report the results of optical spectroscopy of the gamma-ray classical novae V339 Del (2013) and V5668 Sgr (PNV J18365700-2855420/Nova Sgr 2015 No. 2) supplemented by UV and X-ray observations obtained with Swift. Our spectra were obtained with the Steward Observatory Bok 2.3 m telescope (+B&C), the MDM 2.4 m Hiltner telescope (+OSMOS), the 6.5 m MMT (+BlueChannel), and the 2 x 8.4 m Large Binocular Telescope (+MODS1 and PEPSI) between 2013 August and 2015 September. The PEPSI spectra cover all or part of the 384-907 nm spectral region at a resolution of up to 270,000 (1 km/s). This is the highest resolution available on any 8-10 m class telescope. V339 Del was discovered on 2015 August 14.58 by Itagaki at V about 6.8. This nova reached a peak magnitude of about 4.3 making it one of the brightest novae of this century. Because of its exceptional brightness it has been observed at a variety of wavelengths and by a host of observatories both on the ground and in space. V5668 Sgr was discovered on 2015 March 15.634 by Seach at a magnitude of 6.0. It subsequently reached a maximum brightness of about 4.0 in late March. High resolution PEPSI spectra obtained in early April show dramatic variations in the multi-component P Cygni-type line profiles. V5668 Sgr was observed to form dust in June thereafter fading to about 13th magnitude. Our recent observations show that it has now evolved into the nebular phase. SS acknowledges partial support from NSF and NASA grants to ASU. CEW acknowledges support from NASA.

  12. Discovery of $^{34g,m}$Cl$(p,\\gamma)^{35}$Ar resonances activated at classical nova temperatures

    CERN Document Server

    Fry, C; Bishop, S; Brown, B A; Chen, A A; Faestermann, T; Hertenberger, R; Parikh, A; Pérez-Loureiro, D; Wirth, H -F; García, A; Ortez, R

    2015-01-01

    Background: The thermonuclear $^{34g,m}$Cl($p,\\gamma$)$^{35}$Ar reaction rates are unknown due to a lack of experimental nuclear physics data. Uncertainties in these rates translate to uncertainties in $^{34}$S production in models of classical novae on oxygen-neon white dwarfs. $^{34}$S abundances have the potential to aid in the classification of presolar grains. Purpose: Determine resonance energies for the $^{34g,m}$Cl($p,\\gamma$)$^{35}$Ar reactions within the region of astrophyical interest for classical novae to a precision of a few keV as an essential first step toward constraining their thermonuclear reaction rates. Method: $^{35}$Ar excited states were populated by the $^{36}$Ar($d,t$)$^{35}$Ar reaction at $E$(d)=22~MeV and reaction products were momentum analyzed by a high resolution quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph. Results: Seventeen new $^{35}$Ar levels have been detected at a statistically significant level in the region $E_x\\approx$~5.9-6.7~MeV ($E_r$ \\textless~800~ k...

  13. Synthesis of C-rich dust in CO nova ourbursts

    CERN Document Server

    Jose, Jordi; Eid, Mounib F El

    2016-01-01

    Context. Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in stellar binary systems. The material transferred onto the white dwarf piles up under degenerate conditions, driving a thermonuclear runaway. In those outbursts, about 10-7 - 10-3 Msun, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, or Al, for ONe novae) are ejected into the interstellar medium. The large concentrations of metals spectroscopically inferred in the nova ejecta reveal that the (solar-like) material transferred from the secondary mixes with the outermost layers of the underlying white dwarf. Aims. Most theoretical models of nova outbursts reported to date yield, on average, outflows characterized by O > C, from which only oxidized condensates (e.g, O-rich grains) would be expected, in principle. Methods. To specifically address whether CO novae can actually produce C-rich dust, six different hydrodynamic nova models have been evolved, from accreti...

  14. First Direct Measurement of the ^{17}O(p,\\gamma)^{18}F Reaction Cross-Section at Gamow Energies for Classical Novae

    CERN Document Server

    Scott, D A; DiLeva, A; Formicola, A; Aliotta, M; Anders, M; Bemmerer, D; Broggini, C; Campeggio, M; Corvisiero, P; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Laubenstein, M; Menegazzo, R; Marta, M; Napolitani, E; Prati, P; Rigato, V; Roca, V; Somorjai, E; Salvo, C; Straniero, O; Strieder, F; Szücs, T; Terrasi, F; Trezzi, D

    2012-01-01

    Classical novae are important contributors to the abundances of key isotopes, such as the radioactive ^{18}F, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The ^{17}O(p,\\gamma)^{18}F reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range Ecm = 200 - 370 keV appropriate to hydrogen burning in classical novae. In addition, the E=183 keV resonance strength, \\omega \\gamma=1.67\\pm0.12 \\mueV, has been measured with the highest precision to date. The uncertainty on the ^{17}O(p,\\gamma)^{18}F reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis.

  15. Review of the ultraviolet studies of galactic novae

    International Nuclear Information System (INIS)

    The ultraviolet studies of galactic novae both in outburst and also in quiescence have provided new and fundamental data on these exploding stars. As a direct result of the IUE spectral studies, we have identified a new class of novae in which the outburst occurs on an ONeMg white dwarf. We have also been able to determine ejected masses, elemental abundances, and ultraviolet light curves for a wide variety of nova outbursts. 70 refs

  16. Very high energy gamma-ray follow-up observations of novae and dwarf novae with the MAGIC telescopes

    CERN Document Server

    López-Coto, R; Bednarek, W; Desiante, R; Longo, F

    2015-01-01

    In the last few years the Fermi-LAT instrument has detected GeV gamma-ray emission from several novae. Such GeV emission can be interpreted in terms of inverse Compton emission from electrons accelerated in the shock or in terms of emission from hadrons accelerated in the same conditions. The latter might reach much higher energies and could produce a second component in the gamma-ray spectrum at TeV energies. We perform follow-up observations of selected novae and dwarf novae in search of the second component in TeV energy gamma rays. This can shed light on the acceleration process of leptons and hadrons in nova explosions. We have performed observations with the MAGIC telescopes of 3 sources, a symbiotic nova YY Her, a dwarf nova ASASSN-13ax and a classical nova V339 Del, shortly after their outbursts. We did not detect TeV gamma-ray emission from any of the objects observed. The TeV upper limits from MAGIC observations and the GeV detection by Fermi constrain the acceleration parameters for electrons and h...

  17. Experimental Study of 17O(p,α)14N and 17O(p,γ)18F for Classical Nova Nucleosynthesis

    International Nuclear Information System (INIS)

    We investigated the proton-capture reactions on 17O occurring in classical nova explosions. We observed a previously undiscovered resonance at ERlab=194.1±0.6 keV in the 17O(p,α)14N reaction, with a measured resonance strength ωγpα=1.6±0.2 meV. We studied in the same experiment the 17O(p,γ)18F reaction by an activation method and the resonance-strength ratio was found to be ωγpα/ωγpγ=470±50. The corresponding excitation energy in the 18F compound nucleus was determined to be 5789.8±0.3 keV by γ-ray measurements using the 14N(α,γ)18F reaction. These new resonance properties have important consequences for 17O nucleosynthesis and γ-ray astronomy of classical novae

  18. EFFECTS OF A COMPANION STAR ON SLOW NOVA OUTBURSTS—TRANSITION FROM STATIC TO WIND EVOLUTIONS

    International Nuclear Information System (INIS)

    Two types of nova evolutions can occur in low-mass white dwarfs of ∼0.5-0.7 M☉, i.e., an evolution with optically thick winds like in usual classical novae, or an another type of evolution without them like in the symbiotic nova PU Vul. The latter type is characterized by spectra with no indication of strong winds as well as a long-lasting flat optical peak in its light curve. We propose a transition from evolution with no optically thick wind to usual evolution with optically thick winds as a new outburst model for slow novae that show a relatively long-lasting multipeak phase followed by a wind phase like in the slow novae V723 Cas, HR Del, and V5558 Sgr. We calculated nova envelopes with one-dimensional approximation of the companion's effects and found that when the companion star is deeply embedded in the extended nova envelope, the structure of the static envelope approaches that of the optically thick wind solution. Thus, the transition from static to wind solution is triggered by the effect of the companion. The transition occurs in a close binary nova like V723 Cas, but is not triggered in a long-period binary like PU Vul. We reconfirm our previous results that the frictional energy deposition is negligibly small in almost all hydrogen/helium novae because of the low envelope density at the orbit.

  19. The 2015 super-active state of recurrent nova T CrB and the long term evolution after the 1946 outburst

    CERN Document Server

    Munari, U; Cherini, G

    2016-01-01

    The recurrent nova T CrB has entered in 2015 a phase of unprecedented high activity. To trace something equivalent, it is necessary to go back to 1938, before the last nova eruption in 1946. The 2015 super-active state is characterized by: a large increase in the mean brightness (Delta B =0.72 mag over the uderlying secular trend), vanishing of the orbital modulation from the B-band lightcurve, and appearance of strong and high ionization emission lines, on top of a nebular continuum that overwhelms at optical wavelengths the absoption spectrum of the M giant. Among the emission lines, HeII 4686 attains a flux in excess of Hgamma, the full set of OIII and NIII lines involved in the Bowen fluorescence mechanism are strong and varying in intensity in phase with HeII 4686, and OIV and [NeV] are present. A large increase in the radiation output from the hot source is reponsible for a large expansion in the ionized fraction of the M giant wind. The wind is completely ionized in the direction to the observer. A hig...

  20. The 2015 super-active state of recurrent nova T CrB and the long term evolution after the 1946 outburst

    Science.gov (United States)

    Munari, Ulisse; Dallaporta, Sergio; Cherini, Giulio

    2016-08-01

    The recurrent nova T CrB has entered in 2015 a phase of unprecedented high activity. To trace something equivalent, it is necessary to go back to 1938, before the last nova eruption in 1946. The 2015 super-active state is characterized by: a large increase in the mean brightness (ΔB=0.72 mag over the underlying secular trend), vanishing of the orbital modulation from the B-band lightcurve, and appearance of strong and high ionization emission lines, on top of a nebular continuum that overwhelms at optical wavelengths the absorption spectrum of the M giant. Among the emission lines, HeII 4686 attains a flux in excess of Hγ, the full set of OIII and NIII lines involved in the Bowen fluorescence mechanism are strong and varying in intensity in phase with HeII 4686, and OIV and [NeV] are present. A large increase in the radiation output from the hot source is responsible for a large expansion in the ionized fraction of the M giant wind. The wind is completely ionized in the direction to the observer. A high electron density is supported by the weakness of forbidden lines and by the large amplitude and short time scale of the reprocessing by the nebular material of the highly variable photo-ionization input from the hot source. During the super-active state the nebula is varying to and from ionization-bounded and density-bounded conditions, and the augmented irradiation of the cool giant has changed the spectral type of its side facing the WD from M3III to M2III, i.e. an increase of ˜80 K in effective temperature.

  1. Radio emission from novae

    International Nuclear Information System (INIS)

    The nature and measurement of radio emission from novae is discussed. The classical novae for which there are reported measurements of radio flux densities are listed. The three which have been studied most extensively are the slow nova HR Delta, the moderate speed nova FH Ser and the fast nova V1500 Cyg. Two different types of models have been used to model classical novae, the variable speed model and a Hubble flow model. V1500 Cyg has been observed in both radio and infrared spectra. The behaviour which explains this is discussed. Estimates of distance shell, mass and kinetic energy have been made from the data. Radioemissions from related objects and nova remnants are also discussed. (U.K.)

  2. Infrared emission from novae

    CERN Document Server

    Evans, A

    2012-01-01

    We review infrared observations of classical and recurrent novae, at wavelengths >3microns, including both broad-band and spectroscopic observations. In recent years infrared spectroscopy in particular has revolutionised our understanding of the nova phenomenon, by revealing fine-structure and coronal lines, and the mineralogy of nova dust. Infrared spectroscopic facilities that are, or will be, becoming available in the next 10 - 20 years have the potential for a comprehensive study of nova line emission and dust mineralogy, and for an unbiassed assessment of the extragalactic nova populations.

  3. Novae in globular clusters

    International Nuclear Information System (INIS)

    We present the first light-curve analysis of Population II novae that appeared in M31 globular clusters. Our light-curve models, based on the optically thick wind theory, reproduce well both the X-ray turn-on and turnoff times with the white dwarf (WD) mass of about 1.2 M ☉ for M31N 2007-06b in Bol 111 and about 1.37 M ☉ for M31N 2010-10f in Bol 126. The transient supersoft X-ray source CXO J004345 in Bol 194 is highly likely a nova remnant of 1.2-1.3 M ☉ WD. These WD masses are quite consistent with the temperatures deduced from X-ray spectra. We also present the dependence of nova light curves on the metallicity in the range from [Fe/H] = 0.4 to –2.7. Whereas strong optically thick winds are accelerated in Galactic disk novae owing to a large Fe opacity peak, only weak winds occur in Population II novae with low Fe abundance. Thus, nova light curves are systematically slow in low Fe environment. For an extremely low Fe abundance normal nova outbursts may not occur unless the WD is very massive. We encourage V or y filter observation rather than R as well as high cadence X-ray monitorings to open quantitative studies of extragalactic novae.

  4. The first two transient supersoft X-ray sources in M 31 globular clusters and the connection to classical novae

    Czech Academy of Sciences Publication Activity Database

    Henze, M.; Pietsch, W.; Haberl, F.; Sala, G.; Quimby, R.; Hernanz, M.; Della Valle, M.; Milne, P.; Williams, G.G.; Burwitz, V.; Greiner, J.; Stiele, H.; Hartmann, D. H.; Kong, A. K. H.; Hornoch, Kamil

    2009-01-01

    Roč. 500, č. 2 (2009), s. 769-779. ISSN 0004-6361 Institutional research plan: CEZ:AV0Z10030501 Keywords : M 31 * novae * globular clusters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.179, year: 2009

  5. Very-high-energy {\\gamma}-ray observations of novae and dwarf novae with the MAGIC telescopes

    CERN Document Server

    Ahnen, M L; Antonelli, L A; Antoranz, P; Babic, A; Banerjee, B; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Chatterjee, A; Clavero, R; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Di Pierro, F; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Glawion, D Eisenacher; Elsaesser, D; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giammaria, P; Godinović, N; Muñoz, A González; Guberman, D; Hanabata, Y; Hayashida, M; Herrera, J; Hose, J; Hrupec, D; Hughes, G; Idec, W; Kellermann, H; Kodani, K; Konno, Y; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Majumdar, P; Makariev, M; Mallot, K; Maneva, G; Manganaro, M; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palacio, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Saito, T; Saito, K; Satalecka, K; Scapin, V; Schultz, C; Schweizer, T; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Steinbring, T; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Torres, D F; Toyama, T; Treves, A; Verguilov, V; Vovk, I; Will, M; Zanin, R; Desiante, R; Hays, E

    2015-01-01

    Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV {\\gamma}-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. In this case it is expected that protons in the same conditions can be accelerated to much higher energies. Consequently they may produce a second component in the {\\gamma}-ray spectrum at TeV energies. Aims. We aim to explore the very-high-energy domain to search for {\\gamma}-ray emission above 50 GeV and to shed light on the acceleration process of leptons and hadrons in nova explosions. Methods. We have performed observations with the MAGIC telescopes of the classical nova V339 Del shortly after the 2013 outburst, triggered by optical and subsequent GeV {\\gamma}-ray detec- tions. We also briefly report on VHE observations of the symbiotic nova YY Her and the dwarf nova ASASSN-13ax. We complement the TeV MAGIC observations with the analysis of con- temporaneous Fermi-...

  6. Spectral mapping of the spiral structures in IP Pegasi on the decline from an outburst

    CERN Document Server

    Baptista, R; Thomas, G; Baptista, Raymundo; Haswell, Carole A.; Thomas, Gino

    2002-01-01

    (abridged) We report eclipse mapping of time resolved spectroscopy of the dwarf nova IP Pegasi on the late decline from the May 1993 outburst. The spiral arms are still visible some 8 days after the onset of the outburst. Their fractional contribution to the continuum emission is similar to that measured close to outburst maximum, whereas their orientation is rotated by 58 degrees with respect to the spirals seen in the eclipse map at outburst maximum. Velocity-resolved light curves across the Halpha and the HeI lines show the classical rotational disturbance, with the blue side of the line being eclipsed earlier than the red side. The differences between the Halpha and the HeI maps are significant. The spiral arms are clearly seen in the HeI maps, with the receding arm being stronger in the red side while the approaching arm is stronger in the blue side of the line. The analysis of the Halpha maps suggests that this emission arises mainly from a large and vertically-extended region which we interpret as an o...

  7. Novae in Globular Clusters

    CERN Document Server

    Kato, Mariko; Henze, Martin

    2013-01-01

    We present the first light curve analysis of Population II novae that appeared in M31 globular clusters. Our light curve models, based on the optically thick wind theory, reproduce well both the X-ray turn-on and turnoff times with the white dwarf (WD) mass of about 1.2 Mo for M31N 2007-06b in Bol 111 and about 1.37 Mo for M31N 2010-10f in Bol 126. The transient supersoft X-ray source CXO J004345 in Bol 194 is highly likely a nova remnant of 1.2 -- 1.3 Mo WD. These WD masses are quite consistent with the temperatures deduced from X-ray spectra. We also present the dependence of nova light curves on the metallicity in the range from [Fe/H]=0.4 to -2.7. Whereas strong optically thick winds are accelerated in Galactic disk novae owing to a large Fe opacity peak, only weak winds occur in Population II novae with low Fe abundance. Thus, nova light curves are systematically slow in low Fe environment. For an extremely low Fe abundance normal nova outbursts may not occur unless the WD is very massive. We encourage V...

  8. Rapid Dust Formation in Novae: The Speed Class - Formation Timescale Correlation Explained

    CERN Document Server

    Williams, S C; Darnley, M J; Evans, A; Zubko, V; Shafter, A W

    2013-01-01

    Observations show that the time of onset of dust formation in classical novae depends strongly on their speed class, with dust typically taking longer to form in slower novae. Using empirical relationships between speed class, luminosity and ejection velocity, it can be shown that dust formation timescale is expected to be essentially independent of speed class. However, following a nova outburst the spectrum of the central hot source evolves, with an increasing proportion of the radiation being emitted short-ward of the Lyman limit. The rate at which the spectrum evolves also depends on the speed class. We have therefore refined the simple model by assuming photons at energies higher than the Lyman limit are absorbed by neutral hydrogen gas internal to the dust formation sites, therefore preventing these photons reaching the nucleation sites. With this refinement the dust formation timescale is theoretically dependent on speed class and the results of our theoretical modification agree well with the observat...

  9. Classical-Nova Contribution to the Milky Way's $^{26}$Al Abundance: Exit Channel of the Key $^{25}$Al($p,\\gamma$)$^{26}$Si Resonance

    CERN Document Server

    Bennett, M B; Chipps, K A; José, J; Liddick, S N; Santia, M; Bowe, A; Chen, A A; Cooper, N; Irvine, D; McNeice, E; Montes, F; Naqvi, F; Ortez, R; Pain, S D; Pereira, J; Prokop, C; Quaglia, J; Quinn, S J; Schwartz, S B; Shanab, S; Simon, A; Spyrou, A; Thiagalingam, E

    2013-01-01

    Classical novae are expected to contribute to the 1809-keV Galactic $\\gamma$-ray emission by producing its precursor $^{26}$Al, but the yield depends on the thermonuclear rate of the unmeasured $^{25}$Al($p,\\gamma$)$^{26}$Si reaction. Using the $\\beta$ decay of $^{26}$P to populate the key $J^{\\pi}=3^+$ resonance in this reaction, we report the first evidence for the observation of its exit channel via a $1741.6 \\pm 0.6 (\\textrm{stat}) \\pm 0.3 (\\textrm{syst})$ keV primary $\\gamma$ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured $\\gamma$-ray energy and intensity with other experimental data on $^{26}$Si, we find the center-of-mass energy and strength of the resonance to be $E_r = 414.9 \\pm 0.6(\\textrm{stat}) \\pm 0.3 (\\textrm{syst}) \\pm 0.6(\\textrm{lit.})$ keV and $\\omega\\gamma = 23 \\pm 6 (\\textrm{stat})^{+11}_{-10}(\\textrm{lit.})$ meV, respectively, where the last uncertainties are from adopted literature data. We use hydrodynamic nova simulations to model $...

  10. Neon novae, recurrent novae, and type I supernovae

    International Nuclear Information System (INIS)

    Over the past few years, we have been investigating the effects of accretion onto massive white dwarfs and its implications for their growth in mass toward the Chandrasekhar limit, in attempts to identify a possible relationship between SN I and novae. In our studies we have considered accretion at various mass accretion rates onto a variety of different white dwarf masses. We have found that there is a critical white dwarf mass above which a significant fraction of the accreted mass can remain on the white dwarf after the outburst. Below this value of the white dwarf mass, all of the accreted mass, plus core material dredged up into the envelope, is ejected as a result of the explosion. Our latest results include accretion and boundary layer heating produced by the infalling material. From these studies, we have identified some members of the class of recurrent novae, those involving a thermonuclear runaway, as the novae that are occurring on very massive white dwarfs and evolving toward an SN I explosion. One of the outgrowths of our uv studies of novae in outburst has been the identification of a class of novae which eject material that is very rich in the elements from oxygen to aluminum. We have shown that these outbursts occur on ONeMg white dwarfs, which are necessarily very massive white dwarfs. 11 refs

  11. The reproducible radio outbursts of SS Cygni

    CERN Document Server

    Russell, T D; Sivakoff, G R; Altamirano, D; O'Brien, T J; Page, K L; Templeton, M R; Koerding, E G; Knigge, C; Rupen, M P; Fender, R P; Heinz, S; Maitra, D; Markoff, S; Migliari, S; Remillard, R A; Russell, D M; Sarazin, C L; Waagen, E O

    2016-01-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disk material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows th...

  12. Spectrophotometry of DWARF Novae

    International Nuclear Information System (INIS)

    The spectrophotometry of seven dwarf novae was obtained from lambda lambda3800-5200 A three objects were observed during outburst and four near minimum. The Balmer lines in emission and absorption have similar widths (approx4540 km s-1). RU Peg, SS Cyg and AB Dra show weak C II lambda4227 in emission. EM Cyg shows strong He II lambda 4686 in emission during outburst. CY Lyr and UU Aq1 have, near maximum, equivalent widths comparable with those of a B3 III star. The emission line ratios from optically thin steady state accretion disc models are lower than the observed values. The latter are approx.3 times greater than Case B recombination values. The observed He I/H I flux ratios are consistent with the predicted values by Williams and Ferguson (1982) for models with high helium abundance. (author)

  13. Spectrophotometry of DWARF Novae

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, J.; Costero, R.

    1983-01-01

    The spectrophotometry of seven dwarf novae was obtained from lambda lambda3800-5200 A three objects were observed during outburst and four near minimum. The Balmer lines in emission and absorption have similar widths (approx4540 km s/sup -1/). RU Peg, SS Cyg and AB Dra show weak C II lambda4227 in emission. EM Cyg shows strong He II lambda 4686 in emission during outburst. CY Lyr and UU Aq1 have, near maximum, equivalent widths comparable with those of a B3 III star. The emission line ratios from optically thin steady state accretion disc models are lower than the observed values. The latter are approx.3 times greater than Case B recombination values. The observed He I/H I flux ratios are consistent with the predicted values by Williams and Ferguson (1982) for models with high helium abundance.

  14. Transient Classification and Novae Ejecta

    CERN Document Server

    Williams, Robert

    2016-01-01

    A third parameter, in addition to luminosity and rate of brightness decline, that is derived from the spectra of transients is suggested as a means of more accurately classifying objects in outburst. Principal component analysis of the spectra of transients is suggested as the best way to determine the third parameter. A model is suggested for novae ejecta that is based on the ballistic ejection of an ensemble of clouds having a wide range of sizes. Short term brightness fluctuations of novae, the formation of dust, and the production of X-ray emission follow naturally from such a picture of the evolving clouds.

  15. Near-infrared studies of the carbon monoxide and dust-forming Nova V5668 Sgr

    Science.gov (United States)

    Banerjee, D. P. K.; Srivastava, Mudit K.; Ashok, N. M.; Venkataraman, V.

    2016-01-01

    We present near-infrared (NIR) observations of Nova V5668 Sgr, discovered in outburst on 2015 March 15.634 UT, between 2 and 107 d after outburst. NIR spectral features are used to classify it as a Fe II class of nova. The spectra follow the evolution of the spectral lines from a P Cygni stage to a pure emission phase where the shape of the profiles suggests the presence of a bipolar flow. A notable feature is the presence of carbon monoxide first overtone bands which are seen in emission. The CO emission is modelled to make estimates of the mass, temperature and column density to be (0.5-2.0) × 10-8 M⊙, 4000 ± 300 K and (0.36-1.94) × 1019 cm-2, respectively. The 12C/13C ratio is estimated to be ˜1.5. V5668 Sgr was a strong dust producer exhibiting the classical deep dip in its optical light curve during dust formation. Analysis of the dust SED yields a dust mass of 2.7 × 10-7 M⊙, a blackbody angular diameter of the dust shell of 42 mas and a distance estimate to the nova of 1.54 kpc which agrees with estimates made from MMRD relations.

  16. Ultraviolet observations of LMC nova 1988

    International Nuclear Information System (INIS)

    This currently bright novae was first detected in outburst on March 21, 1988. Its discovery has given us the opportunity of studying the first extragalactic nova in the ultraviolet and we have, therefore, obtained a number of LWP and SWP spectra when it was at maximum. We have also obtained a high dispersion LWP spectrum in order to study the ISM in the Large Magellanic Cloud on a slightly different line-of-slight from that analyzed using SN 1987A

  17. Nuclear ashes and outflow in the eruptive star Nova Vul 1670

    CERN Document Server

    Kaminski, Tomasz; Tylenda, Romuald; Hajduk, Marcin; Patel, Nimesh A; Kraus, Alexander

    2015-01-01

    CK Vulpeculae was observed in outburst in 1670-16721, but no counterpart was seen until 1982, when a bipolar nebula was found at its location. Historically, CK Vul has been considered to be a nova (Nova Vul 1670), but a similarity to 'red transients', which are more luminous than classical nova and thought to be the result of stellar collisions, has re-opened the question of CK Vul's status. Red transients cool to resemble late M-type stars, surrounded by circumstellar material rich in molecules and dust. No stellar source has been seen in CK Vul, though a radio continuum source was identified at the expansion centre of the nebula. Here we report CK Vul is surrounded by chemically rich molecular gas with peculiar isotopic ratios, as well as dust. The chemical composition cannot be reconciled with a nova or indeed any other known explosion. In addition, the mass of the surrounding gas is too high for a nova, though the conversion from observations of CO to a total mass is uncertain. We conclude that CK Vul is ...

  18. Analysis of the AAVSO light curves of 21 dwarf novae

    International Nuclear Information System (INIS)

    Measurements of all observed outbursts of 21 dwarf novae during a three-year interval (JD2442300-JD2443300), using the data records of the AAVSO, are reported. Relationships among the rise time, outburst length, decline time, quiescent interval, maximum V magnitude, and physical-system parameters (such as orbital period and masses of the component stars) were investigated. The results confirm some, but not all, of the correlations previously found for the best-studied system SS Cyg and other less consistent surveys. The long-outburst and short-outburst separation characteristic of the SU UMa class are used to identify several prime suspects for this group

  19. Serendipitous discovery of a dwarf Nova in the Kepler field near the G dwarf KIC 5438845

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Alexander; Ayres, Thomas R. [Center for Astrophysics and Space Astronomy, University of Colorado, 593 UCB, Boulder, CO 80309-0593 (United States); Neff, James E.; Wells, Mark A. [Department of Physics and Astronomy, College of Charleston, 66 George Street, Charleston, SC 29424 (United States); Kowalski, Adam [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hawley, Suzanne [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Berdyugina, Svetlana [Kiepenheuer Institut für Sonnenphysik, University of Freiburg, Freiburg, D-79104 (Germany); Harper, Graham M. [School of Physics, Trinity College, Dublin 2 (Ireland); Korhonen, Heidi [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Piskunov, Nikolai [Department of Astronomy and Space Physics, Uppsala University, Uppsala SE-751-20 (Sweden); Saar, Steven [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Walkowicz, Lucianne, E-mail: Alexander.Brown@colorado.edu [Astrophysical Sciences Department, Princeton University, Princeton, NJ 08544-1001 (United States)

    2015-02-01

    The Kepler satellite provides a unique window into stellar temporal variability by observing a wide variety of stars with multi-year, near-continuous, high precision, optical photometric time series. While most Kepler targets are faint stars with poorly known physical properties, many unexpected discoveries should result from a long photometric survey of such a large area of sky. During our Kepler Guest Observer programs that monitored late-type stars for starspot and flaring variability, we discovered a previously unknown dwarf nova that lies within a few arcseconds of the mid-G dwarf star KIC 5438845. This dwarf nova underwent nine outbursts over a 4 year time span. The two largest outbursts lasted ∼17–18 days and show strong modulations with a 110.8 minute period and a declining amplitude during the outburst decay phase. These properties are characteristic of an SU UMa-type cataclysmic variable. By analogy with other dwarf nova light curves, we associate the 110.8 minute (1.847 hr) period with the superhump period, close to but slightly longer than the orbital period of the binary. No precursor outbursts are seen before the super-outbursts and the overall super-outburst morphology corresponds to Osaki and Meyer “Case B” outbursts, which are initiated when the outer edge of the disk reaches the tidal truncation radius. “Case B” outbursts are rare within the Kepler light curves of dwarf novae. The dwarf nova is undergoing relatively slow mass transfer, as evidenced by the long intervals between outbursts, but the mass transfer rate appears to be steady, because the smaller “normal” outbursts show a strong correlation between the integrated outburst energy and the elapsed time since the previous outburst. At super-outburst maximum the system was at V ∼ 18, but in quiescence it is fainter than V ∼ 22, which will make any detailed quiescent follow-up of this system difficult.

  20. THE DUSTY NOVA V1065 CENTAURI (NOVA CEN 2007): A SPECTROSCOPIC ANALYSIS OF ABUNDANCES AND DUST PROPERTIES

    International Nuclear Information System (INIS)

    We examine the ejecta evolution of the classical nova V1065 Centauri, constructing a detailed picture of the system based on spectrophotometric observations obtained from 9 to approximately 900 days post-outburst with extensive coverage from optical to mid-infrared wavelengths. We estimate a reddening toward the system of E(B-V) = 0.5 ± 0.1, based upon the B - V color and analysis of the Balmer decrement, and derive a distance estimate of 8.7+2.8-2.1 kpc. The optical spectral evolution is classified as P ofe Nne Ao according to the CTIO Nova Classification system of Williams et al. Photoionization modeling yields absolute abundance values by number, relative to solar of He/H = 1.6 ± 0.3, N/H = 144 ± 34, O/H = 58 ± 18, and Ne/H = 316 ± 58 for the ejecta. We derive an ejected gas mass of Mg = (1.6 ± 0.2) x 10-4 Msun. The infrared excess at late epochs in the evolution of the nova arises from dust condensed in the ejecta composed primarily of silicate grains. We estimate a total dust mass, Md , of order (0.2-3.7) x 10-7 Msun, inferred from modeling the spectral energy distribution observed with the Spitzer IRS and Gemini-South GNIRS spectrometers. Based on the speed class, neon abundance, and the predominance of silicate dust, we classify V1065 Cen as an ONe-type classical nova.

  1. Recurrent Novae - A Review

    CERN Document Server

    Mukai, Koji

    2014-01-01

    In recent years, recurrent nova eruptions are often observed very intensely in wide range of wavelengths from radio to optical to X-rays. Here I present selected highlights from recent multi-wavelength observations. The enigma of T Pyx is at the heart of this paper. While our current understanding of CV and symbiotic star evolution can explain why certain subset of recurrent novae have high accretion rate, that of T Pyx must be greatly elevated compared to the evolutionary mean. At the same time, we have extensive data to be able to estimate how the nova envelope was ejected in T Pyx, and it turns to be a rather complex tale. One suspects that envelope ejection in recurrent and classical novae in general is more complicated than the textbook descriptions. At the end of the review, I will speculate that these two may be connected.

  2. The outburst of V713 Cephei in August 2009

    CERN Document Server

    Boyd, David; Koff, Robert; Miller, Ian; Staels, Bart

    2010-01-01

    During the outburst of V713 Cephei in August 2009 the times of 8 eclipses were measured and these, together with 5 eclipse timings obtained during quiescence in August 2007, provide an improved orbital period of 0.085418432(4)d. No superhumps were observed in the light curve indicating this was a normal UG-type dwarf nova outburst. We found the eclipse depth decreased linearly with rising system excitation level, falling from ~3 magnitudes in quiescence to ~2 magnitudes during outburst. The depth and totality of eclipses in quiescence suggests a high orbital inclination. We saw no variation in the FWHM of eclipses between quiescence and outburst despite a significant change in shape of the eclipse profile.

  3. Nova-driven winds in globular clusters

    International Nuclear Information System (INIS)

    Recent sensitive searches for Hα emission from ionized intracluster gas in globular clusters have set upper limits that conflict with theoretical predictions. We suggest that nova outbursts heat the gas, producing winds that resolve this discrepancy. The incidence of novae in globular clusters, the conversion of kinetic energy of the nova shell to thermal energy of the intracluster gas, and the characteristics of the resultant winds are discussed. Calculated emission from the nova-driven models does not conflict with any observations to date. Some suggestions are made concerning the most promising approaches for future detection of intracluster gas on the basis of these models. The possible relationship of nova-driven winds of globular cluster X-ray sources is also considered

  4. NLTE model atmospheres for the hottest white dwarfs: Spectral analysis of the compact component in nova V4743 Sgr

    CERN Document Server

    Rauch, T; Gonzales-Riestra, R; Nelson, T; Still, M; Werner, K; Wilms, J; 10.1088/0004-637X/717/1/363

    2010-01-01

    Half a year after its outburst in September 2002, nova V4743 Sgr evolved into the brightest supersoft X-ray source in the sky with a flux maximum around 30A. We calculated grids of synthetic energy distributions (SEDs) based on NLTE model atmospheres for the analysis of the hottest white dwarfs and present the result of fits to Chandra and XMM-Newton grating X-ray spectra of V4743 Sgr of outstanding quality, exhibiting prominent resonance lines of C V, C VI, N VI, N VII, and O VII in absorption. The nova reached its highest effective temperature (Teff = 740 +/- 70kK) around April 2003 and remained at that temperature at least until September 2003. We conclude that the white dwarf is massive, about 1.1 - 1.2 Msun. The nuclear-burning phase lasted for 2 to 2.5 years after the outburst, probably the average duration for a classical nova. The photosphere of V4743 Sgr was strongly carbon deficient (about times solar) and enriched in nitrogen and oxygen (> 5 times solar). Especially the very low C/N ratio indicates...

  5. X-Ray Emission from an Asymmetric Blast Wave and a Massive White Dwarf in the Gamma Ray Emitting Nova V407 CYG

    Science.gov (United States)

    Nelson, Thomas; Donato, Davide; Mukai, Koji; Sokoloski, Jennifer; Chomiuk, Laura

    2012-01-01

    Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equilibrium and non-equilibrium ionization plasmas at the time of peak X-ray brightness, indicating a strong asymmetry in the density of the emitting region. Comparing a simple model to the data, we find that the X-ray evolution is broadly consistent with nova ejecta driving a forward shock into the dense wind of the Mira companion. We detect a highly absorbed soft X-ray component in the spectrum during the first 50 days of the outburst that is consistent with supersoft emission from the nuclear burning white dwarf. The high temperature and short turn off time of this emission component, in addition to the observed breaks in the optical and UV lightcurves, indicate that the white dwarf in the binary is extremely massive. Finally, we explore the connections between the X-ray and GeV-ray evolution, and propose that the gamma ray turn-off is due to the stalling of the forward shock as the ejecta reach the red giant surface.

  6. V2487 Oph 1998: a puzzling recurrent nova observed with XMM-Newton

    Science.gov (United States)

    Hernanz, M.; Sala, G.; Ospina, N.

    2014-07-01

    V2487 Oph exploded as a classical nova in 1998. Several years later it was identified as a recurrent nova, with a previous eruption in 1900. Most recurrent novae host massive white dwarfs (WDs), which could increase in mass after each eruption, finally reaching the Chandrasekar mass and exploding as type Ia supernovae, if CO WDs. We observed V2487 Oph with XMM-Newton between 2 and 9 years after its explosion, to study its post-outburst behavior, and the WD and companion star properties. The emission revealed restablished accretion onto a magnetic WD in a cataclysmic variable of the intermediate polar (IP) type. Interestingly, V2487 Oph was also detected in hard X-rays with INTEGRAL/IBIS, and was again tentatively classified as IP. There's not yet a confirmation of P_{spin}(WD) < P_{orbit}, the defining property of IPs. V2487 Oph is not the first nova exploding in a magnetic CV, but it is indeed challenging to reach explosive conditions without genuine accretion disks. Also, the type of binary system should be reconciled with the fact of being recurrent (where larger accretion rates than in CVs are required). It will be discussed how XMM-Newton observations (EPIC and RGS) provide insight into such a puzzling object.

  7. Thermal radio emission from novae & symbiotics with the Square Kilometre Array

    OpenAIRE

    O’Brien, T J.; Rupen, M.; Chomiuk, L.; Ribeiro, V. A. R. M.; Bode, M.; Sokoloski, J.; Woudt, P.A.

    2014-01-01

    The thermal radio emission of novae during outburst enables us to derive fundamental quantities such as the ejected mass, kinetic energy, and density profile of the ejecta. Recent observations with newly-upgraded facilities such as the VLA and e-MERLIN are just beginning to reveal the incredibly complex processes of mass ejection in novae (ejections appear to often proceed in multiple phases and over prolonged timescales). Symbiotic stars can also exhibit outbursts, which are sometimes accomp...

  8. Nuclear Reaction Rate Uncertainties and their effects on Nova Nucleosynthesis Modeling

    OpenAIRE

    Hix, W. Raphael; Smith, Michael S.; Mezzacappa, Anthony; Starrfield, Sumner; Smith, Donald L.

    2001-01-01

    The nucleosynthesis and other observable consequences of a nova outburst depend sensitively on the details of the thermonuclear runaway which initiates the outburst. One important source of uncertainty in our current models is the nuclear reaction data used as input for the evolutionary calculations. We present preliminary results of the first analyses of the impact on nova nucleosynthesis of all reaction rate uncertainties considered simultaneously.

  9. Modelling nova populations in galaxies

    Science.gov (United States)

    Chen, Hai-Liang; Woods, T. E.; Yungelson, L. R.; Gilfanov, M.; Han, Zhanwen

    2016-05-01

    Theoretical modelling of the evolution of classical and recurrent novae plays an important role in studies of binary evolution, nucleosynthesis and accretion physics. However, from a theoretical perspective the observed statistical properties of novae remain poorly understood. In this paper, we have produced model populations of novae using a hybrid binary population synthesis approach for differing star formation histories (SFHs): a starburst case (elliptical-like galaxies), a constant star formation rate case (spiral-like galaxies) and a composite case (in line with the inferred SFH for M31). We found that the nova rate at 10 Gyr in an elliptical-like galaxy is ˜10-20 times smaller than a spiral-like galaxy with the same mass. The majority of novae in elliptical-like galaxies at the present epoch are characterized by low-mass white dwarfs (WDs), long decay times, relatively faint absolute magnitudes and long recurrence periods. In contrast, the majority of novae in spiral-like galaxies at 10 Gyr have massive WDs, short decay times, are relatively bright and have short recurrence periods. The mass-loss time distribution for novae in our M31-like galaxy is in agreement with observational data for Andromeda. However, it is possible that we underestimate the number of bright novae in our model. This may arise in part due to the present uncertainties in the appropriate bolometric correction for novae.

  10. Near Infrared studies of the carbon-monoxide and dust forming nova V5668 Sgr

    CERN Document Server

    Banerjee, D P K; Ashok, N M; Venkataraman, V

    2015-01-01

    We present near-infrared (NIR) observations of Nova V5668 Sgr, discovered in outburst on 2015 March 15.634 UT, between 2d to 107d after outburst. NIR spectral features are used to classify it as a FeII class of nova. The spectra follow the evolution of the spectral lines from a P Cygni stage to a pure emission phase where the shape of the profiles suggests the presence of a bipolar flow. A notable feature is the presence of carbon monoxide first overtone bands which are seen in emission. The CO emission is modeled to make estimates of the mass, temperature and column density to be (0.5--2.0)$\\times$ 10$^{-8}$ M$_\\odot$, 4000 $\\pm$ 300K and (0.36--1.94)$\\times$ 10$^{19}$ cm$^{-2}$ respectively. The $^{12}$C/$^{13}$C ratio is estimated to be $\\sim$ 1.5. V5668 Sgr was a strong dust producer exhibiting the classical deep dip in its optical light curve during dust formation. Analysis of the dust SED yields a dust mass of 2.7 $\\times$ 10${^{\\rm -7}}$ $M_\\odot $, a blackbody angular diameter of the dust shell of 42 ...

  11. The formation of Cataclysmic Variables: the influence of nova eruptions

    CERN Document Server

    Nelemans, G; Repetto, S; Toonen, S; Phinney, E S

    2015-01-01

    The theoretical and observed populations of pre-cataclysmic variables (pre-CVs) are dominated by systems with low-mass white dwarfs (WDs), while the WD masses in CVs are typically high. In addition, the space density of CVs is found to be significantly lower than theoretical models. We investigate the influence of nova outbursts on the formation and (initial) evolution of CVs. In particular, we calculate the stability of the mass transfer in case all the material accreted on the WD is lost in classical novae, and part of the energy to eject the material comes from a common-envelope like interaction with the companion. In addition, we study the effect of an asymmetry in the mass ejection, that may lead to small eccentricities in the orbit. We find that a common-envelope like ejection significantly decreases the stability of the mass transfer, in particular for low-mass WD. Similarly, the influence of asymmetric mass loss can be important for short-period systems and even more so for low-mass WD, but likely dis...

  12. Disc structure and variability in dwarf novae

    Science.gov (United States)

    Harlaftis, Emilios Theofanus

    An introduction is given to dwarf novae reviewing the current research status in the field. We present IUE observations of Z Cha which support the mass transfer instability as the cause of the superoutbursts observed in SU UMa type dwarf novae. Comparison between the superoutburst and a normal outburst of Z Cha shows that the disc is flatter and has significantly less azimuthal structure than during superoutburst. Z Cha exhibits a soft x-ray deficit during superoutburst compared to OY Car. We find that the secondary star of Z Cha contributes approximately 30 percent of the infrared flux at peak of outburst. The second part of the thesis presents results from the 1988 International Time Project at the Observatorio del Roque de los Muchachos. Investigation of the behavior of SU UMa and YZ Cnc is carried out through the outburst cycle. The secular changes of the equivalent widths of both systems shows an increasing trend even during quiescence and are caused by the continuum decrease. Both systems show a low-velocity emission component which contaminates the wings of the H(alpha) profile. In addition to doppler broadening, the Stark effect is found to cause significant broadening to the line profile. The radial dependence of the emission lines is discussed in relation to other cataclysmic variables. H(alpha) emission from the secondary star of YZ Cnc is found during superoutburst, during outburst and during quiescence after outburst. Photometry during late decline of outburst shows a sinusoidal, weak variation peaking at 0.5 orbital phase and which is related to heating of the red star or to a transient disc event. During quiescence, the flickering is found to be caused by the bright spot. This modulation increases with time and is maximum before the outburst. Doppler tomography of IP Peg during quiescence reveals an emission line distribution not consistent to the standard model. We find Balmer emission from the secondary star, at a level of only 2.5 percent of the

  13. Infrared Observations of novae in the SOFIA era

    CERN Document Server

    Gehrz, R D; Helton, L A; Woodward, C E

    2015-01-01

    Classical novae inject chemically enriched gas and dust into the local inter-stellar medium (ISM). Abundances in the ejecta can be deduced from infrared (IR) forbidden line emission. IR spectroscopy can determine the mineralogy of grains that grow in nova ejecta. We anticipate the impact that NASA's new Stratospheric Observatory for Infrared Astronomy (SOFIA) will have on future IR studies of novae.

  14. Eclipsing SU UMa-Type Dwarf Nova 1RXS J003828.7+250920 During thE "Period Gap". I. Multiperiodicity and Color Features in 2011-2012

    Science.gov (United States)

    Pavlenko, E. P.; Sosnovskij, A. A.; Katysheva, N. A.; Kato, T.; Littlefield, K.

    2016-09-01

    Results are reported from multicolor photometric observations of the SU UMa-type dwarf nova 1RXS J003828.7+250920 in 2011, roughly a year after the super-outburst of 2010, and in 2012, when the object was in a quiescent state and underwent an outburst. Partial eclipses were observed in the system with depths of about 0m.6 in all color bands, both in the quiescent state and during the outburst. The orbital period of the system, 0.09451001(4) days, was determined for the first time and identifies the object as a dwarf nova in the "gap" in the orbital-period distribution of the cataclysmic variables. The ephemerides for the middle of the eclipse are determined. The average light curve profile resembles the "classical" light curve of U Gem. The orbital periodicity in the brightness variations of 1RXS J003828.7+250920 coexists with another signal with a period of 0.092 days, which we interpret as a period of negative superhumps. The color temperatures derived from the color indices may indicate multicomponent emission from 1RXS J003828.7+250920 by sources which appear to be hot and cold parts of the accretion disk and a hot spot on the accretion disk.

  15. Nova-induced mass transfer variations

    CERN Document Server

    Kolb, U; Schenker, K; Howell, S; Kolb, Ulrich; Rappaport, Saul; Schenker, Klaus; Howell, Steve

    2001-01-01

    We investigate variations of the mass transfer rate in cataclysmic variables (CVs) that are induced by nova outbursts. The ejection of nova shells leads to a spread of transfer rates in systems with similar orbital period. The effect is maximal if the specific angular momentum in the shell is the same as the specific orbital angular momentum of the white dwarf. We show analytically that in this case the nova-induced widening of the mass transfer rate distribution can be significant if the system, in the absence of nova outbursts, is close to mass transfer instability (i.e., within a factor of ~1.5 of the critical mass ratio). Hence the effect is negligible below the period gap and for systems with high-mass white dwarfs. At orbital periods between about 3 and 6 hrs the width of the mass transfer rate distribution exceeds an order of magnitude if the mass accreted on the white dwarf prior to the runaway is larger than a few 10^{-4} M_sun. At a given orbital period in this range, systems with the highest transf...

  16. "Velhos são os Trapos": do positivismo clássico à nova era "Aged People are Rags": from classic positivism to the new era

    Directory of Open Access Journals (Sweden)

    Carlos António Laranjeira

    2010-12-01

    Full Text Available Para que o ser humano consiga concretizar o direito à vida plena e digna, para que se justifique completamente a procura pela longevidade, deve socialmente permitir-se que essa vida maior seja igualmente melhor. Para que isso aconteça algo tem que mudar nas representações da velhice, no respeito pelas particularidades que a envolvem e pela oferta de estruturas específicas. A velhice é uma fase da vida que tem sido socialmente desvalorizada, negativamente representada, o que se reflete na qualidade de vida dos idosos. Esse ensaio reflexivo pretende desvelar os principais debates culturais sobre a velhice, ao analisar duas estruturas ideológicas dicotômicas sobre o envelhecimento e a velhice. Os resultados são defensores da necessidade de construção de imagens positivas sobre o envelhecimento, para combater os tradicionais modelos de declínio e de despessoalização. Realça-se a complexidade e a heterogeneidade dos fenômenos em análise sublinhando a aplicação de novas estratégias destinadas à construção de uma nova era sobre a velhice, ancorada nos paradigmas de cidadania e pluralidade sociais.For human beings to fulfil their right to live a full and dignified life, to completely justify the quest for longevity, it must be socially possible for that greater life to be also a better one. For this to occur, something needs to change in the representations of old age, in the respect for its particularities, and in the supply of specific structures. Old age is a stage of life that has been socially devalued, being represented in a negative way. This reflects on the quality of life of older people. This reflexive essay shall explore the main cultural debates regarding old age by analysing two dichotomic ideological structures on aging and old age. The results defend the need to build positive images regarding aging in order to fight the traditional models of decline and depersonalization. Noteworthy is the complexity and

  17. Novae news

    CERN Multimedia

    2012-01-01

    As announced in the previous Bulletin, Novae has opened a new snack bar on the Flagstaff car park, just a few metres from CERN's reception area (Building 33).   Just a few metres from the CERN Reception, the new Novae snack point welcomes visitors and CERNois. Opening hours Currently: Monday to Friday, 8 a.m. to 4 p.m. From September: Monday to Friday, 7:45 a.m. to 5 p.m.; Saturdays from 8 a.m. to 2 p.m. The snack bar selection includes breakfast, starting at 2.70 CHF, cold dishes from 5 CHF, and hot dishes from 6 CHF.   Novae has also installed a 24-hour-a-day food vending machine in the CERN hostel (Building 39) and in Building 13. You can buy pasta and cooked dishes for 6.50 CHF to 8 CHF. In addition, a groceries vending machine has been installed in the main building, just across from the news kiosk. Nearly 60 different items are available around the clock. Finally, Novae has introduced a new payment system in several buildings on the Meyrin site. It accepts credit ca...

  18. V4743 Sgr, a magnetic nova?

    Science.gov (United States)

    Zemko, P.; Orio, M.; Mukai, K.; Bianchini, A.; Ciroi, S.; Cracco, V.

    2016-05-01

    Two XMM Newton observations of Nova V4743 Sgr (Nova Sgr 2002) were performed shortly after it returned to quiescence, 2 and 3.5 years after the explosion. The X-ray light curves revealed a modulation with a frequency of ≃0.75 mHz, indicating that V4743 Sgr is most probably an intermediate polar (IP). The X-ray spectra have characteristics in common with known IPs, with a hard thermal plasma component that can be fitted only assuming a partially covering absorber. In 2004 the X-ray spectrum had also a supersoft blackbody-like component, whose temperature was close to that of the white dwarf (WD) in the supersoft X-ray phase following the outburst, but with flux by at least two orders of magnitude lower. In quiescent IPs, a soft X-ray flux component originates at times in the polar regions irradiated by an accretion column, but the supersoft component of V4743 Sgr disappeared in 2006, indicating a possible origin different from accretion. We suggest that it may have been due to an atmospheric temperature gradient on the WD surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. An optical spectrum obtained with SALT 11.5 years after the outburst showed a prominent He II λ4686 line and the Bowen blend, which reveal a very hot region, but with peak temperature shifted to the ultraviolet (UV) range. V4743 Sgr is the third post-outburst nova and IP candidate showing a low-luminosity supersoft component in the X-ray flux a few years after the outburst.

  19. GW Librae: Still Hot Eight Years Post-Outburst

    CERN Document Server

    Szkody, Paula; Gaensicke, Boris T; Chote, Paul; Nelson, Peter; Myers, Gordon; Toloza, Odette; Waagen, Elizabeth O; Sion, Edward M; Sullivan, Denis J; Townsley, Dean M

    2016-01-01

    We report continued Hubble Space Telescope (HST) ultraviolet spectra and ground-based optical photometry and spectroscopy of GW Librae eight years after its largest known dwarf nova outburst in 2007. This represents the longest cooling timescale measured for any dwarf nova. The spectra reveal that the white dwarf still remains about 3000 K hotter than its quiescent value. Both ultraviolet and optical light curves show a short period of 364-373 s, similar to one of the non-radial pulsation periods present for years prior to the outburst, and with a similar large UV/optical amplitude ratio. A large modulation at a period of 2 h (also similar to that observed prior to outburst) is present in the optical data preceding and during the HST observations, but the satellite observation intervals did not cover the peaks of the optical modulation so it is not possible to determine its corresponding UV amplitude. The similarity of the short and long periods to quiescent values implies the pulsating, fast spinning white d...

  20. Modelling nova populations in galaxies

    CERN Document Server

    Chen, Hai-Liang; Yungelson, L R; Gilfanov, M; Han, Zhanwen

    2016-01-01

    Theoretical modelling of the evolution of classical and recurrent novae plays an important role in studies of binary evolution, nucleosynthesis and accretion physics. However, from a theoretical perspective the observed statistical properties of novae remain poorly understood. In this paper, we have produced model populations of novae using a hybrid binary population synthesis approach for differing star formation histories (SFHs): a starburst case (elliptical-like galaxies), a constant star formation rate case (spiral-like galaxies) and a composite case (in line with the inferred SFH for M31). We found that the nova rate at 10\\;Gyr in an elliptical-like galaxy is $\\sim 10-20$ times smaller than a spiral-like galaxy with the same mass. The majority of novae in elliptical-like galaxies at the present epoch are characterized by low mass white dwarfs (WDs), long decay times, relatively faint absolute magnitudes and long recurrence periods. In contrast, the majority of novae in spiral-like galaxies at 10\\;Gyr hav...

  1. Herschel Observations of Circinus X-1 during Outburst and Quiescence

    Science.gov (United States)

    Harrison, Thomas E.; Gelino, Dawn M.; Buxton, Michelle; Fost, Tyler

    2014-07-01

    We have used the Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging REceiver instruments on the Herschel Space Observatory to observe Cir X-1 both in and out of outburst. We detected Cir X-1 during outburst at 70 μm. Unfortunately, a cold background source dominates Cir X-1 at longer wavelengths. We have assembled optical and infrared (IR) data for Cir X-1 to model its spectral energy distribution (SED) in both quiescence and outburst and find that in both states it is consistent with a heavily reddened, 10,000 K blackbody. We believe this behavior is completely consistent with previous suggestions that these outbursts are due to accretion disk events, not unlike those of dwarf novae. To explore the behavior of other low-mass X-ray binaries with reported synchrotron jets, we have extracted and/or compiled optical and near- and mid-IR data sets for five such systems to construct their SEDs. The Z-source GX 349+2 and the black hole system GRS 1915+105 have strong and variable mid-IR excesses that suggest synchrotron emission. The other Z-sources have rather weak (or no) IR excesses that can be explained as reddened blackbody spectra with the addition of either synchrotron or bremsstrahlung components. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  2. Early Spectroscopy of the 2010 Outburst of U Scorpii

    CERN Document Server

    Yamanaka, Masayuki; Kawabata, Koji S; Fujii, Mitsugu; Tanabe, Kenji; Imamura, Kazuyoshi; Komatsu, Tomoyuki; Arai, Akira; Sasada, Mahito; Itoh, Ryosuke; Harao, Tatsuya; Kunitomi, Nanae; Nagae, Osamu; Nose, Mikiha; Ohsugi, Takashi; Okushima, Takako; Sakimoto, Kiyoshi; Yoshida, Michitoshi

    2010-01-01

    We present early spectroscopy of the recurrent nova U~Sco during the outburst in 2010. We successfully obtained time-series spectra at $t_{\\rm d}=$0.37--0.44~d, where $t_{\\rm d}$ denotes the time from the discovery of the present outburst. This is the first time-resolved spectroscopy on the first night of U Sco outbursts. At $t_{\\rm d}\\sim 0.4$~d the H$\\alpha$ line consists of a blue-shifted ($-5000$ km s$^{-1}$) narrow absorption component and a wide emission component having triple peaks, a blue ($\\sim -3000$ km s$^{-1}$), a central ($\\sim 0$ km s$^{-1}$) and a red ($\\sim +3000$ km s$^{-1}$) ones. The blue and red peaks developed more rapidly than the central one during the first night. This rapid variation would be caused by the growth of aspherical wind produced during the earliest stage of the outburst. At $t_{\\rm d}=1.4$~d the H$\\alpha$ line has a nearly flat-topped profile with weak blue and red peaks at $\\sim \\pm 3000$ km s$^{-1}$. This profile can be attributed to a nearly spherical shell, while the ...

  3. The soft X-ray turnoff of Nova Muscae 1983

    Science.gov (United States)

    Shanley, L.; Ogelman, H.; Gallagher, J. S.; Orio, M.; Krautter, J.

    1995-01-01

    Nova GQ Muscae 1983 was detected by ROSAT as a luminous 'supersoft' X-ray source in 1992, nearly a decade after outburst. Further, this is the only classical postnova known to have maintained constant luminosity on a timescale predicted by theoretical models. Follow-up observations were made with the ROSAT position-sensitive proportional counter in 1993 January and September, and complemented with B-band photometry taken in 1993 January. By 1993 January, the X-ray count rate had declined by a factor of 17, while there was neither an appreciable decrease in the optical magnitude nor a change in the amplitude of modulation. In 1993 September the soft X-ray flux was below the ROSAT threshold limit, implying a decrease of a factor greater than or equal to 30 in the count rate. This decline can be interpreted by the turnoff of nuclear processes due to the complete consumption of the residual hydrogen-rich envelope. However, the optical luminosity of the system is not simply coupled to the X-ray luminosity (e.g., through reprocessing).

  4. Atomic processes in nova shells

    International Nuclear Information System (INIS)

    The unusual spectra of the spatially-resolved nova shells of DQ Her, T Aur and CP Pup are reviewed. Because calculations for these conditions have not been made, recombination models of HI, HeI and CNO from a neutral to a doubly ionized state were constructed. The models are described and the results presented for densities at various temperatures. A photoionization model is also described. The effects of non-uniform density distributions in nova shells have been investigated and the observational consequences discussed. A model of the CP Pup shell is described and the evolution of this plasma during the nova's constant luminosity phase traced. The properties of neon novae are summarized and compared with the features seen in the optical spectra of old classical novae. Enhanced neon abundances are used in the model of the CP Pup Shell to investigate its effect on the evolution of the shell. Finally, the results of some near-infrared observations made on the shells of CP Pup, RR Pic and T Pyx are reported. 245 refs., 48 tabs., 17 figs

  5. High spectral resolution monitoring of Nova V339 Delphini with TIGRE

    Science.gov (United States)

    De Gennaro Aquino, I.; Schröder, K.-P.; Mittag, M.; Wolter, U.; Jack, D.; Eenens, P.; González-Pérez, J. N.; Hempelmann, A.; Schmitt, J. H. M. M.; Hauschildt, P. H.; Rauw, G.

    2015-09-01

    Aims: We investigate the early development of the classical nova V339 Del (Nova Delphini 2013) through high-resolution optical spectroscopy. To study the structure of the ejecta, we focus on the evolution of the absorption and emission features and the changes within the line profiles. Methods: We obtained spectra with the robotic 1.2 m telescope TIGRE equipped with the HEROS spectrograph (R = 20 000, wavelength coverage from 3800 to 8800 Å). Our data set covers the outburst from 3 until 121 days after discovery. Results: We provide a qualitative analysis of the spectra, describing the line profiles evolution and providing a rich list of identified lines. During the optically thick phase, we detected several blue-shifted absorption features from s-processed elements, whose origin is unclear. The presence of strong lines from C/O and the absence of Neon features confirm that the nature of the central white dwarf is a CO type. The later "nebular" phase spectra show evidence of the non-spherical, inhomogeneous structure of the ejecta. The detailed evolution of the line profiles and appearance of high ionization species (e.g. N III, O III, He II, [Fe VII]) are direct consequences of the re-ionization of the ejecta during the peak of the soft X-ray emission.

  6. Infrared spectra of nova dust shells

    International Nuclear Information System (INIS)

    Results of fitting blackbody and pseudoblackbody functions to infrared photometry for three classical novae are briefly summarised. It is concluded that: the data are consistent with blackbody fits for all times for all three novae; the dust shell temperatures of LW Ser and NQ Vul rose after an initial decline, subsequently levelled out and finally fell; neither pre-existing grain, nor grain growth models, in their original forms, adequately account for the time-dependence. (Auth.)

  7. ONeMg novae and the evolution of their shells

    International Nuclear Information System (INIS)

    The properties of ONeMg novae are summarized and compared with the features seen in the optical spectra of old classical novae. None of the old novae had ejection velocities as high as those of the ONeMg novae. Photo-ionization models of nova shells are used to trace how the ejecta from ONeMg novae should evolve, and to predict what old ONeMg nova shells should look like. Finally, the model we developed for CP Pup is used with enhanced neon abundances to see the effect it has on the evolution of the shell. A neon enhancement of between 10 and 100 times the solar abundance would most probably not have been noticed in the spectra of this object. (author)

  8. Optical and ultraviolet observations of Nova Vul 1987

    International Nuclear Information System (INIS)

    We present a brief summary of the outburst for a nova that was discovered in November 1987 and has been followed since that time. Although we were able to observe it with the IUE at maximum, its ultraviolet energy faded rapidly and after the first two weeks we were no longer able to observe it at IUE wavelengths. It was observed to form a thick dust shell and currently is in the nebular stage

  9. Population of post-nova supersoft X-ray sources

    CERN Document Server

    Soraisam, Monika D; Wolf, William M; Bildsten, Lars

    2015-01-01

    Novae undergo a supersoft X-ray phase of varying duration after the optical outburst. Such transient post-nova supersoft X-ray sources (SSSs) are the majority of the observed SSSs in M31. In this paper, we use the post-nova evolutionary models of Wolf et al. to compute the expected population of post-nova SSSs in M31. We predict that depending on the assumptions about the WD mass distribution in novae, at any instant there are about 250-600 post-nova SSSs in M31 with (unabsorbed) 0.2-1.0 keV luminosity L_x>10^36 erg/s. Their combined unabsorbed luminosity is of the order of ~10^39 erg/s. Their luminosity distribution shows significant steepening around log(L_x)~37.7-38 and becomes zero at L_x~2x10^38 erg/s, the maximum L_x achieved in the post-nova evolutionary tracks. Their effective temperature distribution has a roughly power law shape with differential slope of ~4-6 up to the maximum temperature of T_eff~1.5x10^6 K. We compare our predictions with the results of the XMM-Newton monitoring of the central fi...

  10. CNO "Breakout" and Nucleosynthesis in Classical Novae

    OpenAIRE

    Glasner, S. Ami; Truran, Jame. W.

    2008-01-01

    For very slow white dwarf accretors in CV's Townsley and Bildsten (2004) found a relation between the accretion rate and the central temperature of the white dwarf Tc. According to this relation for accretion rates less than 10^-10 solar masses per year Tc is much lower than 10^7 K. Motivated by this study we follow the thermonuclear runaway on massive white dwarfs (M_WD=1.25 - 1.40 solar masses) with Tc lower than 10^7 K, accreting matter of solar composition. We demonstrate that in that ran...

  11. CNO "Breakout" and Nucleosynthesis in Classical Novae

    CERN Document Server

    Glasner, S Ami

    2008-01-01

    For very slow white dwarf accretors in CV's Townsley and Bildsten (2004) found a relation between the accretion rate and the central temperature of the white dwarf Tc. According to this relation for accretion rates less than 10^-10 solar masses per year Tc is much lower than 10^7 K. Motivated by this study we follow the thermonuclear runaway on massive white dwarfs (M_WD=1.25 - 1.40 solar masses) with Tc lower than 10^7 K, accreting matter of solar composition. We demonstrate that in that range of the relevant parameter space (Tc,M_WD and accretion rate) the slope of the relation between the peak temperatures achieved during the runaway and Tc becomes much steeper than its value for Tc above 10^7 K. The peak temperatures we derive can lead to nuclear breakout from the conventional "hot carbon-nitrogen-oxygen" cycle. When breakout conditions are achieved the heavy element abundances can show a much wider variety than what is possible with the common enrichment mechanisms.

  12. Continuous `stunted' outbursts detected from the cataclysmic variable KIC 9202990 using Kepler data

    Science.gov (United States)

    Ramsay, Gavin; Hakala, Pasi; Wood, Matt A.; Howell, Steve B.; Smale, Alan; Still, Martin; Barclay, Thomas

    2016-01-01

    Based on early Kepler data, Østensen et al. found that KIC 9202990 showed a 4-h and a two-week photometric period. They suggested the 4-h period was a signature of an orbital period; the longer period was possibly due to precession of an accretion disc and KIC 9202990 was a cataclysmic variable with an accretion disc which is always in a bright state (a nova-like system). Using the full Kepler data set on KIC 9202990 which covers 1421 d (Quarter 2-17), and includes 1-min cadence data from the whole of Quarters 5 and 16, we find that the 4-h period is stable and therefore a signature of the binary orbital period. In contrast, the 10-12 d period is not stable and shows an amplitude between 20 and 50 per cent. This longer period modulation is similar to those nova-like systems which show `stunted' outbursts. We discuss the problems that a precessing disc model has in explaining the observed characteristics and indicate why we favour a stunted outburst model. Although such stunted events are considered to be related to the standard disc instability mechanism, their origin is not well understood. KIC 9202990 shows the lowest amplitude and shortest period of continuous stunted outburst systems, making it an ideal target to better understand stunted outbursts and accretion instabilities in general.

  13. Synthesis of radioactive nuclei and $\\gamma$-line radiation from novae

    CERN Document Server

    Kudryashov, A D; Tutukov, A V

    1999-01-01

    We carried out kinetic calculations of thermonuclear burning in the hydrogen-rich matter to simulate nucleosynthesis yields in nova outbursts. These results are used to calculate the light curves of annihilation gamma-ray line from N, O and F radioactive isotopes.

  14. SW Sex stars, old novae, and the evolution of cataclysmic variables

    CERN Document Server

    Schmidtobreick, Linda

    2014-01-01

    The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.

  15. Photometry and spectroscopy of the luminous red nova PSNJ14021678+5426205 in the galaxy M101

    Science.gov (United States)

    Goranskij, V. P.; Barsukova, E. A.; Spiridonova, O. I.; Valeev, A. F.; Fatkhullin, T. A.; Moskvitin, A. S.; Vozyakova, O. V.; Cheryasov, D. V.; Safonov, B. S.; Zharova, A. V.; Hancock, T.

    2016-01-01

    We present the results of the study of a red nova from the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor,we used the data from the Digital Sky Survey and amateur photos available on the Internet. In the period between April 1993 and July 2014, the brightness of the progenitor gradually increased by 2_ \\cdot ^m 2 in the V-band. At the peak of the first outburst in mid-November 2014, the star reached an absolute visual magnitude of - 12_ \\cdot ^m 75 but was discovered later, in February 2015, in a repeated outburst at the magnitude of - 11_ \\cdot ^m 65. The amplitude of the outburst was minimum among the red novae, only 5_ \\cdot ^m 6 in V-band. The Hα emission line and the background of a cool supergiant continuum with gradually decreasing surface temperature were observed in the spectra. Such process is typical for red novae, although the object under study showed extreme parameters: maximum luminosity, maximum outburst duration, minimum outburst amplitude, unusual shape of the light curve. This event is interpreted as a massive OB star system components'merging accompanied by formation of a common envelope and then the expansion of this envelope with minimal energy losses.

  16. The evolution of Rapid Burster outbursts

    NARCIS (Netherlands)

    Guerriero, R; Fox, DW; Kommers, J; Lewin, WHG; Rutledge, R; Moore, CB; Morgan, E; Van Paradijs, J; Van der Klis, M; Bildsten, L; Dotani, T

    1999-01-01

    We describe the evolutionary progression of an outburst of the Rapid Burster. Four outbursts have been observed with the Rossi X-Ray Timing Explorer between 1996 February and 1998 May, and our observations are consistent with a standard evolution over the course of each. An outburst can be divided i

  17. The analysis of spectra of novae taken near maximum

    International Nuclear Information System (INIS)

    We have recently begun a project to analyze ultraviolet spectra of novae obtained at or near maximum optical light. These spectra are characterized by a relatively cool continuum with superimposed permitted emission lines from ions such as FE II, Mg II, and Si II. In contrast, the spectra obtained late in the outburst show only emission lines from highly ionized species and in many cases these are forbidden lines. These ultraviolet data will be used in combination with recent calculations of spherical, expanding, stellar atmospheres for novae to determine elemental abundances by spectral line synthesis. This method is extremely sensitive to the abundances and completely independent of the nebular analyses usually used to obtain novae abundances

  18. A WISE view of novae. I. The data

    CERN Document Server

    Evans, A; Woodward, C E; Helton, L A

    2014-01-01

    We present the results of data-mining the Wide-field Infrared Survey Explorer (WISE) archive for data on classical and recurrent novae. We find that the detections are consistent with dust emission, line emission, emission by a stellar photosphere, or a combination of these. Of the 36 novae detected in one or more WISE bands, 16 are detected in all four; thirty-one known novae are not detected by WISE. We also searched for WISE data on post-WISE novae, to gain information about nova progenitors. In this first paper we consider only the WISE data. In future papers we will provide a more detailed modelling of the WISE data, and discuss WISE data on post-WISE novae - including their variability - and will complement the WISE data with data from other IR surveys.

  19. Dwarf nova-type cataclysmic variable stars are significant radio emitters

    CERN Document Server

    Coppejans, Deanne L; Miller-Jones, James C A; Rupen, Michael P; Sivakoff, Gregory R; Knigge, Christian; Groot, Paul J; Woudt, Patrick A; Waagen, Elizabeth O; Templeton, Matthew

    2016-01-01

    We present 8--12\\,GHz radio light curves of five dwarf nova (DN) type Cataclysmic Variable stars (CVs) in outburst (RX And, U Gem and Z Cam), or superoutburst (SU UMa and YZ Cnc), increasing the number of radio-detected DN by a factor of two. The observed radio emission was variable on time-scales of minutes to days, and we argue that it is likely to be synchrotron emission. This sample shows no correlation between the radio luminosity and optical luminosity, orbital period, CV class, or outburst type; however higher-cadence observations are necessary to test this, as the measured luminosity is dependent on the timing of the observations in these variable objects. The observations show that the previously detected radio emission from SS Cyg is not unique in type, luminosity (in the plateau phase of the outburst), or variability time-scales. Our results prove that DN, as a class, are radio emitters in outburst.

  20. HUBBLE SPACE TELESCOPE AND GROUND-BASED OBSERVATIONS OF V455 ANDROMEDAE POST-OUTBURST

    International Nuclear Information System (INIS)

    Hubble Space Telescope spectra obtained in 2010 and 2011, 3 and 4 yr after the large amplitude dwarf nova outburst of V455 And, were combined with optical photometry and spectra to study the cooling of the white dwarf, its spin, and possible pulsation periods after the outburst. The modeling of the ultraviolet (UV) spectra shows that the white dwarf temperature remains ∼600 K hotter than its quiescent value at 3 yr post-outburst, and still a few hundred degrees hotter at 4 yr post-outburst. The white dwarf spin at 67.6 s and its second harmonic at 33.8 s are visible in the optical within a month of outburst and are obvious in the later UV observations in the shortest wavelength continuum and the UV emission lines, indicating an origin in high-temperature regions near the accretion curtains. The UV light curves folded on the spin period show a double-humped modulation consistent with two-pole accretion. The optical photometry 2 yr after outburst shows a group of frequencies present at shorter periods (250-263 s) than the periods ascribed to pulsation at quiescence, and these gradually shift toward the quiescent frequencies (300-360 s) as time progresses past outburst. The most surprising result is that the frequencies near this period in the UV data are only prominent in the emission lines, not the UV continuum, implying an origin away from the white dwarf photosphere. Thus, the connection of this group of periods with non-radial pulsations of the white dwarf remains elusive

  1. NOVA 201 ultrasonic thickness gage (NOVA Gage)

    Science.gov (United States)

    Garecht, Diane

    1990-01-01

    The measurement integrity of the NOVA 201 digital ultrasonic thickness gage (NOVA gage) was demonstrated by comparing the NOVA gage measurements to the thickness gage measurements, and determining the bias and uncertainty of the NOVA gage when measuring redesigned solid rocket motor (RSRM) hardware per engineering test plans (ETP). The NOVA gage was tested by three different operators on steel and aluminum RSRM hardware for wall thickness. The results show that the measurement bias is not consistent. The uncertainty of the bias is caused by the heterogeneous material properties of the RSRM components that influence the time of flight of ultrasonic waves. The measurement uncertainty inherent to the design and operation of the NOVA gage is less in comparison to the uncertainty of the bias. The total measurement uncertainty cannot be substantially reduced by taking more than one measurement. There is no correlation between bias and the surface finish range of this test unless 3-in-One oil is used as a couplant, in which case there appears to be a slight trend. There is no correlation between uncertainty and the surface finish range. The measurement uncertainty of the NOVA gage can be reduced using 3-in-One oil as a couplant.

  2. Recovery of old novae

    Directory of Open Access Journals (Sweden)

    L. Schmidtobreick

    2004-01-01

    Full Text Available Durante un proyecto a largo plazo dedicado a la investigaci on de novas cl asicas con explosiones de grandes amplitudes hemos llevado a cabo fotometr a a m ultiples longitudes de onda y espectroscop a optica de varios candidatos de novas viejas. Introducimos aqu el objetivo del proyecto, la b usqueda de novas con baja trans- ferencia de masa y per odos orbitales cortos, y explicamos el m etodo para recuperar estas novas viejas a trav es de sus caracter sticas de color. Finalmente nos concentramos en los primeros resultados para una selecci on de objetos de nuestra muestra.

  3. KVN Monitoring Obsevations toward the Recent Outburst Symbiotic Star V407 Cygni

    CERN Document Server

    Cho, Se-Hyung; Yun, Youngjoo

    2015-01-01

    Simultaneous time monitoring observations of H$_{2}$O and SiO maser lines were performed toward the D-type symbiotic binary system V407 Cyg with the Korean VLBI Network single dish radio telescope. These monitoring observations were carried out from March 2, 2010 (optical phase $\\phi$ = 0.0), 8 days before the nova outburst on March 10, 2010 to June 5, 2014 ($\\phi$ = 2.13). Eight days before the nova outburst, we detected the SiO $v$ = 1, 2, $J$ = 1--0 maser lines which exhibited values of 0.51 K ($\\sim$ 6.70 Jy) and 0.71 K ($\\sim$ 9.30 Jy), respectively, while after the outburst we could not detect them on April 2 ($\\phi$ = 0.04), May 5 ($\\phi$ = 0.09), May 8 ($\\phi$ = 0.09), or on June 5, 2010 ($\\phi$ = 0.13) within the upper limits of our KVN observations. After restarting our monitoring observations, we detected SiO $v$ = 2, $J$ = 1--0 masers starting on October 20, 2011 ($\\phi$ = 0.83) and detected SiO $v$ = 1, $J$ = 1--0 masers starting on December 22, 2011 ($\\phi$ = 0.92). These results provide clear e...

  4. GK Per 2015 dwarf nova covered by Suzaku

    CERN Document Server

    Yuasa, Takayuki; Ishida, Manabu

    2016-01-01

    The intermediate polar GK Per exhibited a dwarf nova outburst in March-April 2015. Suzaku X-ray telescope serendipitously captured the onset of the outburst during its pre-scheduled pointing observation spanning four days. In this paper, we present temporal and spectral analysis results of this outburst, together with those from archival data of quiescent obtained in 2009 and 2014. Our temporal analysis confirmed previously reported spin modulation of X-ray count rates in outburst with a WD spin period of P_WD=351.4+/-0.5 s. The modulation is also detected in the hard X-ray band (16-60 keV), and spectral modeling of the absorption suggests obscuration by a dense absorption with a line-of-sight column density of N_H>10^23 cm^-2. A complex time evolution of spin modulation profiles is seen; the spin minimum phase shifts from phase ~0.25 in the first half of the observation to ~0.65 in the second one, and the pulse shape significantly changes epoch by epoch. Spectral fitting in the Fe Kalpha band revealed an inc...

  5. LBT/LUCIFER near-infrared spectroscopy of PV Cephei An outbursting young stellar object with an asymmetric jet

    OpenAIRE

    Caratti o Garatti, A.; Garcia Lopez, R.; Weigelt, G.; Tambovtseva, L. V.; Grinin, V.P.; Wheelwright, H.; Ilee, J. D.

    2013-01-01

    Context. Young stellar objects (YSOs) occasionally experience enhanced accretion events, the nature of which is still poorly understood. The discovery of various embedded outbursting YSOs has recently questioned the classical definition of EXors and FUors. Aims. We present a detailed spectroscopic investigation of the young eruptive star PV Cep, to improve our understanding of its nature and characterise its circumstellar environment after its last outburst in 2004. Methods. The analysis of o...

  6. V899 Mon: An Outbursting Protostar with a Peculiar Light Curve, and Its Transition Phases

    Science.gov (United States)

    Ninan, J. P.; Ojha, D. K.; Baug, T.; Bhatt, B. C.; Mohan, V.; Ghosh, S. K.; Men'shchikov, A.; Anupama, G. C.; Tamura, M.; Henning, Th.

    2015-12-01

    We present a detailed study of V899 Mon (a new member in the FUors/EXors family of young low-mass stars undergoing outburst), based on our long-term monitoring of the source starting from 2009 November to 2015 April. Our optical and near-infrared photometric and spectroscopic monitoring recorded the source transitioning from its first outburst to a short-duration quiescence phase (returning to a second outburst. We report here the evolution of the outflows from the inner region of the disk as the accretion rate evolved in various epochs. Our high-resolution (R ˜ 37,000) optical spectrum could resolve interesting clumpy structures in the outflow traced by various lines. Change in far-infrared flux was also detected between two outburst epochs. Based on our observations, we constrained various stellar and envelope parameters of V899 Mon, as well as the kinematics of its accretion and outflow. The photometric and spectroscopic properties of this source fall between classical FUors and EXors. Our investigation of V899 Mon hints at instability associated with magnetospheric accretion being the physical cause of the sudden short-duration pause of the outburst in 2011. It is also a good candidate to explain similar short-duration pauses in outbursts of some other FUors/EXors sources.

  7. The Expanding Fireball of Nova Delphini 2013

    CERN Document Server

    Schaefer, G H; Gies, D R; Farrington, C D; Kloppenborg, B; Chesneau, O; Monnier, J D; Ridgway, S T; Scott, N; Tallon-Bosc, I; McAlister, H A; Boyajian, T; Maestro, V; Mourard, D; Meilland, A; Nardetto, N; Stee, P; Sturmann, J; Vargas, N; Baron, F; Ireland, M; Baines, E K; Che, X; Jones, J; Richardson, N D; Roettenbacher, R M; Sturmann, L; Turner, N H; Tuthill, P; van Belle, G; von Braun, K; Zavala, R T; Banerjee, D P K; Ashok, N M; Joshi, V; Becker, J; Muirhead, P S

    2015-01-01

    A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting from one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes ...

  8. Outbursts of EX Hydrae Revisited

    CERN Document Server

    Mhlahlo, N; Dhillon, V; Potter, S; Warner, B; Woudt, P

    2007-01-01

    We present optical spectroscopy of EX Hya during its 1991 outburst. This outburst is characterised by strong irradiation of the front face of the secondary star by the white dwarf, an overflowing stream which is seen strongly in HeII and by a dip in the light curves, which extends from 0.1-0.6 in the binary and spin phases. Strong irradiation of the accretion curtain and that of the inner regions of the disc led to strong emission of HeII and to the suppression of the Hg and Hb emission. Disc overflow was observed in quiescence in earlier studies, where the overflow stream material was modulated at high velocities close to 1000 km/s. In outburst, the overflowing material is modulated at even higher velocities (~1500 km/s). These are streaming velocities down the field lines close to the white dwarf. Evidence for material collecting near the outer edge of the disc and corotating with the accretion curtain was observed. In decline, this material and the accretion curtain obscured almost all the emission near bi...

  9. The Investigation of Nova-like Variable MV Lyr during the 1999–2001 Years

    Indian Academy of Sciences (India)

    N. A. Katysheva; S. Yu. Shugarov; E. P. Pavlenko; P. V. Abolmasov

    2002-03-01

    A peculiar nova-like MV Lyr was investigated. The CCD-observations ofMVLyr were continued in Crimea during the outbursts and quiescent states. Last year its behavior became non-typical for ``anti-dwarf novae”. The length of its first deep minimum was 10 years. A modern state is characterized by very strong outbursts and very often changes of the stages. The periods 0.d128 and 0.d136 were obtained for 1998 and 1999 years accordingly. Possibly, a relation between the photometric period and the brightness exists.

  10. OPTICAL AND X-RAY OBSERVATIONS OF M31N 2007-12b: AN EXTRAGALACTIC RECURRENT NOVA WITH A DETECTED PROGENITOR?

    International Nuclear Information System (INIS)

    We report combined optical and X-ray observations of nova M31N 2007-12b. Optical spectroscopy obtained 5 days after the 2007 December outburst shows evidence of very high ejection velocities (FWHM Hα ≅ 4500 km s-1). In addition, Swift X-ray data show that M31N 2007-12b is associated with a Super-Soft Source (SSS) which appeared between 21 and 35 days post-outburst and turned off between then and day 169. Our analysis implies that M WD ∼> 1.3 M sun in this system. The optical light curve, spectrum, and X-ray behavior are consistent with those of a recurrent nova. Hubble Space Telescope observations of the pre-outburst location of M31N 2007-12b reveal the presence of a coincident stellar source with magnitude and color very similar to the Galactic recurrent nova RS Ophiuchi at quiescence, where the red giant secondary dominates the emission. We believe that this is the first occasion on which a nova progenitor system has been identified in M31. However, the greatest similarities of outburst optical spectrum and SSS behavior are with the supposed Galactic recurrent nova V2491 Cygni. A previously implied association of M31N 2007-12b with nova M31N 1969-08a is shown to be erroneous, and this has important lessons for future searches for recurrent novae in extragalactic systems. Overall, we show that suitable complementary X-ray and optical observations can be used not only to identify recurrent nova candidates in M31, but also to determine subtypes and important physical parameters of these systems. Prospects are therefore good for extending studies of recurrent novae into the Local Group with the potential to explore in more detail such important topics as their proposed link to Type Ia Supernovae.

  11. One Thousand New Dwarf Novae from the OGLE Survey

    CERN Document Server

    Mroz, P; Poleski, R; Pietrukowicz, P; Szymanski, M K; Soszynski, I; Wyrzykowski, L; Ulaczyk, K; Kozlowski, S; Skowron, J

    2016-01-01

    We present one of the largest collections of dwarf novae (DNe) containing 1091 objects that have been discovered in the long-term photometric data from the Optical Gravitational Lensing Experiment (OGLE) survey. They were found in the OGLE fields toward the Galactic bulge and the Magellanic Clouds. We analyze basic photometric properties of all systems and tentatively find a population of DNe from the Galactic bulge. We identify several dozen of WZ Sge-type DN candidates, including two with superhump periods longer than 0.09 d. Other interesting objects include SU UMa-type stars with "early" precursor outbursts or a Z Cam-type star showing outbursts during standstills. We also provide a list of DNe which will be observed during the K2 Campaign 9 microlensing experiment in 2016. Finally, we present the new OGLE-IV real-time data analysis system: CVOM, which has been designed to provide continuous real time photometric monitoring of selected CVs.

  12. T Pyxidis: Death by a Thousand Novae

    CERN Document Server

    Patterson, Joseph; Kemp, Jonathan; Monard, Berto; Rea, Robert; Hambsch, Franz-Josef; McCormick, Jennie; Nelson, Peter; Allen, William; Krajci, Thomas; Lowther, Simon; Dvorak, Shawn; Borgman, Jordan; Richards, Thomas; Myers, Gordon; Harlingten, Caisey; Bolt, Greg

    2016-01-01

    We report a 20-year campaign to track the 1.8 hour photometric wave in the recurrent nova T Pyxidis, using the global telescope network of the Center for Backyard Astrophysics. During 1996-2011, that wave was highly stable in amplitude and waveform, resembling the orbital wave commonly seen in supersoft binaries. The period, however, was found to increase on a timescale P/P-dot=3x10^5 years. This suggests a mass transfer rate in quiescence of ~10^-7 M_sol/yr, in substantial agreement with the accretion rate based on the star's luminosity. This is ~2000x greater than is typical for cataclysmic variables of that orbital period. During the post-eruption quiescence (2012-2016), the star continued on its merry but mysterious way - similar luminosity, similar P/P-dot (2.4x10^5 years). The orbital signal became vanishingly weak (300 years of accretion at the pre-outburst rate, but the time between outbursts was only 45 years. Thus the erupting white dwarf seems to have ejected at least 6x more mass than it accreted....

  13. Shortest Recurrence Periods of Forced Novae

    CERN Document Server

    Hachisu, Izumi; Kato, Mariko

    2016-01-01

    We revisit hydrogen shell burning on white dwarfs (WDs) with higher mass accretion rates than the stability limit, \\dot M_stable, above which hydrogen burning is stable. Novae occur with mass accretion rates below the limit. For an accretion rate > \\dot M_stable, a first hydrogen shell flash occurs followed by steady nuclear burning, so the shell burning will not be quenched as long as the WD continuously accretes matter. On the basis of this picture, some persistent supersoft X-ray sources can be explained by binary models with high accretion rates. In some recent studies, however, the claim has been made that no steady hydrogen shell burning exists even for accretion rates > \\dot M_{\\rm stable}. We demonstrate that, in such cases, repetitive flashes occurred because mass accretion was artificially controlled. If we stop mass accretion during the outburst, no new nuclear fuel is supplied, so the shell burning will eventually stop. If we resume mass accretion after some time, the next outburst eventually occu...

  14. Rebirth of Novae as Distance Indicators Due to Efficient Large Telescopes

    CERN Document Server

    Valle, M D; Valle, Massimo Della; Gilmozzi, Roberto

    2002-01-01

    Nova outbursts are the result of strong thermonuclear runaways on the surface of a white dwarf accreting Hydrogen-rich material from a small mass companion. These giant explosions cause the star to increase its brightness by hundreds of thousands of times then making these objects powerful standard candles useful to measure the extragalactic distances.We have used the Very Large Telescope, located in the Chilean Atacama desert, to search for novae in NGC 1316--an early type galaxy in the Fornax cluster. We discovered 4 novae with 3h of observing time. The use of 8-10m class telescopes coupled with new detectors, can dramatically improve the efficiency of nova searches in extragalactic systems.

  15. Spectroscopy and Multi-color Photometry of U Scorpii at the Earliest Stage of 2010 Outburst

    CERN Document Server

    Imamura, Kazuyoshi

    2012-01-01

    We have performed our spectroscopic and multi-color photometric observations of the recurrent nova U Scorpii at the earliest stage of the 2010 outburst. 0.37 days after the discovery of the outburst, we can see broad and prominent emission lines of Balmer series, He I, N II, N III, O I and Mg II on the spectra. The FWHM of H$\\alpha$ line yields an expansion velocity of approximately 6200 km/s. This line also accompanies a blue shifted absorption line (so called P Cygni profile). 1.37 days after the discovery, H$\\alpha$ line shows a nearly flat-topped profile in contrast to the previous day. From our multi-color photometry, we can see its rapid decline (one magnitude per day) of the brightness in each color band.

  16. V4743 Sgr, a magnetic nova?

    CERN Document Server

    Zemko, P; Mukai, K; Bianchini, A; Ciroi, S; Cracco, V

    2016-01-01

    Two XMM Newton observations of Nova V4743 Sgr (Nova Sgr 2002) were performed shortly after it returned to quiescence, 2 and 3.5 years after the explosion. The X-ray light curves revealed a modulation with a frequency of ~0.75 mHz, indicating that V4743 Sgr is most probably an intermediate polar (IP). The X-ray spectra have characteristics in common with known IPs, with a hard thermal plasma component that can be fitted only assuming a partially covering absorber. In 2004 the X-ray spectrum had also a supersoft blackbody-like component, whose temperature was close to that of the white dwarf (WD) in the supersoft X-ray phase following the outburst, but with flux by at least two orders of magnitude lower. In quiescent IPs, a soft X-ray flux component originates at times in the polar regions irradiated by an accretion column, but the supersoft component of V4743 Sgr disappeared in 2006, indicating a possible origin different from accretion. We suggest that it may have been due to an atmospheric temperature gradie...

  17. V390 Nor = Nova Normae 2007

    Science.gov (United States)

    Waagen, Elizabeth O.

    2007-06-01

    Nova Normae 2007 was discovered photographically by William Liller on June 15.086 UT at magnitude 9.4. Precise position measured by G. Bolt from his unfiltered CCD image of June 16.7 UT: 16:32:11.51 -45:09:13.4 (2000.0). Giorgio Di Scala reported to the AAVSO that a low-resolution spectrum indicates a nova a week or so after outburst, with strong H-alpha emission. E. Kazarovets, Sternberg Astronomical Institute, reports that N Nor 07 has been assigned the name V390 Nor. Discovery originally announced in IAU Central Bureau Electronic Telegram 982 (Daniel W. E. Green) and AAVSO Special Notice #49 (Arne Henden). Information in this Alert Notice was received at AAVSO from William Liller, Giorgio Di Scala, or via IAU Circular No. 8850, ed. Daniel W. E. Green. A chart for V390 Nor is available via the Variable Star Plotter (VSP). Go to: http://www.aavso.org/observing/charts/vsp/ and enter the name V390 NOR.

  18. OUTBURSTS OF COMET HALE-BOPP

    Institute of Scientific and Technical Information of China (English)

    Yang Benyou; Zhang Chunsheng; Fan Yixin; Cai Hongfang; Sun Shousheng; Zhang Yan; Sun Linan

    2000-01-01

    In this paper, we present the observations of Comet Hale-Bopp by means of photoelectric and photographic photometry during the period from September to November of 1996. It is shown that there appears to have been 3 outbursts around 24 Sept., 26 Oct. and 13 Nov.; and it is also possible that an event of outburst has taken place around 9 Oct.

  19. VERITAS OBSERVATIONS OF THE NOVA IN V407 CYGNI

    Energy Technology Data Exchange (ETDEWEB)

    Aliu, E. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Archambault, S. [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Bradbury, S. M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Byrum, K. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Decerprit, G. [DESY, Platanenallee 6, 15738 Zeuthen (Germany); Duke, C., E-mail: daniel-d-gall@uiowa.edu, E-mail: kazuma-tsurusaki@uiowa.edu [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); and others

    2012-07-20

    We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 Multiplication-Sign 10{sup -12} erg cm{sup -2} s{sup -1} (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova.

  20. A search for novae in M 31 globular clusters

    International Nuclear Information System (INIS)

    By combining a local sky-fitting algorithm with a Fourier point-spread-function matching technique, nova outbursts have been searched for inside 54 of the globular clusters contained on the Ciardullo et al. (1987 and 1990) H-alpha survey frames of M 31. Over a mean effective survey time of about 2.0 years, no cluster exhibited a magnitude increase indicative of a nova explosion. If the cataclysmic variables (CVs) contained within globular clusters are similar to those found in the field, then these data imply that the overdensity of CVs within globulars is at least several times less than that of the high-luminosity X-ray sources. If tidal capture is responsible for the high density of hard binaries within globulars, then the probability of capturing condensed objects inside globular clusters may depend strongly on the mass of the remnant. 40 refs

  1. A search for novae in M 31 globular clusters

    Science.gov (United States)

    Ciardullo, Robin; Tamblyn, Peter; Phillips, A. C.

    1990-10-01

    By combining a local sky-fitting algorithm with a Fourier point-spread-function matching technique, nova outbursts have been searched for inside 54 of the globular clusters contained on the Ciardullo et al. (1987 and 1990) H-alpha survey frames of M 31. Over a mean effective survey time of about 2.0 years, no cluster exhibited a magnitude increase indicative of a nova explosion. If the cataclysmic variables (CVs) contained within globular clusters are similar to those found in the field, then these data imply that the overdensity of CVs within globulars is at least several times less than that of the high-luminosity X-ray sources. If tidal capture is responsible for the high density of hard binaries within globulars, then the probability of capturing condensed objects inside globular clusters may depend strongly on the mass of the remnant.

  2. Nova Scotia windfields

    Energy Technology Data Exchange (ETDEWEB)

    Watling, B. [Renewable Energy Services Ltd., Windsor, NS (Canada)

    2002-07-01

    Scotian WindFields is a windfield development structure offering the citizens of Nova Scotia an opportunity to participate, with tax advantages, in the development of wind energy resources. This paper highlighted the objective of the financial incentive, its problems and the tool used to implement it. The end result is that Nova Scotians will have the right and opportunity to channel their registered retirement savings plan assets into community controlled corporations which will be capital participants in wind turbine development. Each dollar invested will yield a 30 per cent Nova Scotia investment tax credit. The plan functions through the Scotian WindFields Operating Agreement on Standard Oilfield Operating Agreement. 2 figs.

  3. Optical and Near-Infrared spectroscopy of Nova V1494 Aquilae 1999 #2

    CERN Document Server

    Kamath, U S; Ashok, N M; Mayya, Y D; Sahu, D K

    2005-01-01

    Optical and near-infrared spectroscopic observations of the fast nova V1494 Aquilae 1999 #2 covering various phases -- early decline, transition and nebular -- during the first eighteen months of its post-outburst evolution are presented in this paper. During this period, the nova evolved in the P_fe P_fe^o C_o spectral sequence. The transition from an optically thick wind to a polar blob - equatorial ring geometry is seen in the evolution of the spectral line profiles. There is evidence of density and temperature stratification in the ejecta. Physical conditions in the ejecta have been estimated based on our observations.

  4. A Hubble Space Telescope Survey for Novae in M87. I. Light and Color Curves, Spatial Distributions and the Nova Rate

    CERN Document Server

    Shara, Michael M; Lauer, Tod R; Zurek, David; Neill, J D; Madrid, Juan P; Welch, D L; Baltz, Edward A

    2016-01-01

    The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae. In this first in a series of papers we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. We derive the nova rate for M87: $363_{-45}^{+33}$ novae/yr. We also derive the luminosity-specific nova rate for this galaxy, which is $9.17_{-3.0}^{+2.7} /yr/ 10^{10}L_\\odot,_{K}$. Both rates are 4 times higher higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. We suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow...

  5. Nova program at LLNL

    International Nuclear Information System (INIS)

    At LLNL, successful experimental work is being performed with the Nova laser facility, a solid state laser system using neodymium-doped glass laser technology. Nova is the primary U.S. facility devoted to the study of the indirect drive approach to inertial fusion. In this concept, energy from a laboratory driver is converted to radiation that is used to implode and heat the fusion fuel in an inertial fusion capsule. Nova's principial objective is to demonstrate that laser-driven hohlraums (chambers that trap electromagnetic radiation) can meet the conditions of driver/target coupling efficiency, driver irradiation symmetry, driver pulse-shaping, target preheat, and hydrodynamic stability required by hot spot ignition and by fuel compression in order to realize net fusion gain (fusion energy released/driver energy delivered). Major results within the Nova Program fall within the areas of laser performance, target diagnostics, and implosion experiments. (author) 2 figs

  6. Echelle-MEPSICRON time-resolved spectroscopy of the dwarf nova SS Cygni

    International Nuclear Information System (INIS)

    High-dispersion time-resolved spectroscopy of the dwarf nova SS Cygni was obtained during two consecutive days at the end of an outburst. The emission lines present a double-peaked profile with a peak-to-peak separation of 526±14 km s-1. The lines have a complex structure which includes a narrow asymmetric component coming from a hot spot in the accretion disc or from the chromosphere of the red dwarf. (author)

  7. Echelle-MEPSICRON time-resolved spectroscopy of the dwarf nova SS Cygni

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, J.; Tapia, M. (Universidad Nacional Autonoma de Mexico, Baja California (Mexico). Inst. de Astronomia); Diego, F. (Institute of Oceanographic Sciences, Godalming (UK)); Costero, R.; Ruiz, E.; Salas, L.; Gutierrez, L.; Enriquez, R. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Astronomia)

    1989-10-15

    High-dispersion time-resolved spectroscopy of the dwarf nova SS Cygni was obtained during two consecutive days at the end of an outburst. The emission lines present a double-peaked profile with a peak-to-peak separation of 526{plus minus}14 km s{sup -1}. The lines have a complex structure which includes a narrow asymmetric component coming from a hot spot in the accretion disc or from the chromosphere of the red dwarf. (author).

  8. The Be X-ray Binary Outburst Zoo

    CERN Document Server

    Kretschmar, Peter; Reig, Pablo; Anders, Friedrich

    2013-01-01

    Be X-ray binaries are among the best known transient high-energy sources. Their outbursts are commonly classified into a simple scheme of 'normal' and 'giant' outbursts, but a closer look shows that actual outbursts do not always follow this simple scheme. Recent data show a variety of properties, like pre-flares, shifts of the outburst peaks with respect to the periastron, multi-peaked outbursts etc. We present results from a systematic study of a large number of outbursts monitored by various space missions, comparing outburst properties and their relation to system parameters and current theoretical understanding.

  9. FU Orionis Outbursts and the Solar Nebula

    Science.gov (United States)

    Bell, Robbins; Young, Rich (Technical Monitor)

    1998-01-01

    Protostellar systems are variable on many timescales. The FU Orionis outburst is one of the most drastic forms of variability known to occur in low mass stellar systems. During a typical outburst lasting several decades, system luminosities may be a hundred times what is normal of the quiescent state. FU Orionis outburst events are believed to have significant impacts on the thermal structure of the protosolar nebula. Their existence has been utilized to explain features in the meteoritic record from thermally induced homogenization to chondrule formation. Recent numerical models have shown the viability of the hypothesis that the radiation observed during outburst is emitted by a luminous circumstellar disk transporting mass at a thousand times the quiescent rate. We will begin by describing what is known about the FU Orionis outburst phenomenon from recent observations and theory. We will discuss evidence that suggests that outburst radiation is emitted by a circumstellar disk rather than by the star and will briefly describe the thermal instability as a mechanism for outburst. Additional information is contained in the original extended abstract.

  10. The pre-outburst flare of the A0535+26 August/September 2005 outburst

    OpenAIRE

    Caballero, I.; Santangelo, A.; Kretschmar, P.; Staubert, R.; Postnov, K.; Klochkov, D.; Camero-Arranz, Ascensión; Finger, M. H.; I. Kreykenbohm(University of Erlangen-Nuremberg, Germany); Pottschmidt, K.; Rothschild, R. E.; S. Suchy(IAAT - Institut für Astronomie und Astrophysik, Universität Tübingen, Germany); Wilms, J.; Wilson, C. A.

    2008-01-01

    Aims. We study the spectral and temporal behavior of the High Mass X-ray Binary A 0535+26 during a “pre-outburst flare” which took place ∼5 d before the peak of a normal (type I) outburst in August/September 2005. We compare the studied behavior with that observed during the outburst. Methods. We analyse RXTE observations that monitored A 0535+26 during the outburst. We complete spectral and timing analyses of the data. We study the evolution of the pulse period, present energy-dependent puls...

  11. A 71 second oscillation in the super-soft X-ray flux of V5668 Sgr (Nova Sgr 2015 No. 2)

    Science.gov (United States)

    Page, K. L.; Beardmore, A. P.; Osborne, J. P.

    2015-10-01

    On 2015 August 30 (168 days after outburst), the bright, dust-forming (ATEL #7643, #7862), gamma-ray emitting (ATEL #7283, #7315) nova V5668 Sgr was seen to enter a super-soft X-ray phase (ATEL #8054).

  12. X-ray Eclipse Diagnosis of the Evolving Mass Loss in the Recurrent Nova U Scorpii 2010

    OpenAIRE

    Takei, D.; Drake, J. J.; Tsujimoto, M; Ness, J.-U.; Osborne, J.P.; Starrfield, S.; Kitamoto, S.

    2013-01-01

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27+/-5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contempora...

  13. Measuring the superhump period of the dwarf nova RX J1715.6+6856

    CERN Document Server

    Shears, Jeremy; Sabo, Richard

    2009-01-01

    We report unfiltered CCD observations of the first confirmed superoutburst of the dwarf nova RX J1715.6+6856 in August 2009. At quiescence the star was magnitude 18.3 (CCD, clear). The outburst amplitude was at least 2.4 magnitudes and it lasted at least 6 days, although the first part of the outburst was probably missed. Analysis of the light curve revealed superhumps with peak-to-peak amplitude of 0.1 magnitude, thereby showing it to be a member of the SU UMa family. The mean superhump period was Psh = 0.07086(78) d with a superhump period excess of epsilon = 0.038 and an estimated mass ratio q = 0.167. In the final stages of the outburst, as the star approached quiescence, the superhumps disappeared to be replaced by a modulation corresponding to the orbital period. The star was regularly monitored between August 2007 and September 2009 revealing a total of 12 outbursts, with an outburst frequency of approximately once per month.

  14. Continuous `stunted' outbursts detected from the Cataclysmic Variable KIC 9202990 using Kepler data

    CERN Document Server

    Ramsay, Gavin; Wood, Matt A; Howell, Steve B; Smale, Alan; Still, Martin; Barclay, Tom

    2015-01-01

    Based on early Kepler data, Ostensen et al. (2010) found that KIC 9202990 showed a 4 hr and a two-week photometric period. They suggested the 4 hr period was a signature of an orbital period; the longer period was possibly due to precession of an accretion disk and KIC 9202990 was a cataclysmic variable with an accretion disk which is always in a bright state (a nova-like system). Using the full Kepler dataset on KIC 9202990 which covers 1421 d (Quarter 2--17), and includes 1 min cadence data from the whole of Quarters 5 and 16, we find that the 4 hr period is stable and therefore a signature of the binary orbital period. In contrast, the 10--12 d period is not stable and shows an amplitude between 20--50 percent. This longer period modulation is similar to those nova-like systems which show `stunted' outbursts. We discuss the problems that a precessing disk model has in explaining the observed characteristics and indicate why we favour a stunted outburst model. Although such stunted events are considered to ...

  15. Evolution of the stellar-merger red nova V1309 Scorpii: SED analysis

    CERN Document Server

    Tylenda, R

    2016-01-01

    One very important object for understanding the nature of red novae is V1309 Sco. Its pre-outburst observations showed that, before its red-nova eruption in 2008, it was a contact binary quickly evolving to the merger of the components. It thus provided us with a direct evidence that the red novae result from stellar mergers. We analyse the spectral energy distribution (SED) of the object and its evolution with time. From various optical and infrared surveys and observing programmes carried out with OGLE, HST, VVV, Gemini South, WISE, Spitzer, and Herschel we constructed observed SED in 2010 and 2012. Some limited data are also available for the red-nova progenitor in 2007. We analyse the data with our model of a dusty envelope surrounding a central star. Dust was present in the pre-outburst state of V1309 Sco. Its high temperature (900-1000 K) suggests that this was a freshly formed dust in a presumable mass-loss from the spiralling-in binary. Shortly after its 2008 eruption, V1309~Sco became almost complete...

  16. The Relationship Between X-ray Luminosity and Duty Cycle for Dwarf Novae and their Specific Frequency in the Inner Galaxy

    CERN Document Server

    Britt, C T; Pretorius, M L; Hynes, R I; Jonker, P G; Torres, M A P; Knigge, C; Heinke, C O; Johnson, C B; Steeghs, D; Greiss, S; Nelemans, G

    2015-01-01

    We measure the duty cycles for an existing sample of well observed, nearby dwarf novae using data from AAVSO, and present a quantitative empirical relation between the duty cycle of dwarf novae outbursts and the X-ray luminosity of the system in quiescence. We have found that $\\log DC=0.63(\\pm0.21)\\times(\\log L_{X}({\\rm erg\\,s^{-1}})-31.3)-0.95(\\pm0.1)$, where DC stands for duty cycle. We note that there is intrinsic scatter in this relation greater than what is expected from purely statistical errors. Using the dwarf nova X-ray luminosity functions from \\citet{Pretorius12} and \\citet{Byckling10}, we compare this relation to the number of dwarf novae in the Galactic Bulge Survey which were identified through optical outbursts during an 8-day long monitoring campaign. We find a specific frequency of X-ray bright ($L_{X}>10^{31}\\,{\\rm erg\\,s^{-1}}$) Cataclysmic Variables undergoing Dwarf Novae outbursts in the direction of the Galactic Bulge of $6.6\\pm4.7\\times10^{-5}\\,M_{\\odot}^{-1}$. Such a specific frequency...

  17. The Be X-ray Binary Outburst Zoo II

    Science.gov (United States)

    Kuehnel, M.; Kretschmar, P.; Nespoli, E.; Okazaki, A. T.; Schoenherr, G.; Wilson-Hodge, C. A.; Falkner, S.; Brand, T.; Anders, F.; Schwarm, F.-W.; Kreykenbohm, I.; Mueller, S.; Pottschmidt, K.; Fuerst, F.; Grinberg, V.; Wilms, J.

    2015-03-01

    We have continued our recently started systematic study of Be X-ray binary (BeXRB) outbursts. Specifically, we are developing a catalogue of outbursts including their basic properties based on nearly all available X-ray all-sky-monitors. These properties are derived by fitting asymmetric Gaussians to the outburst lightcurves. This model describes most of the outbursts covered by our preliminary catalogue well; only 13% of all datasets show more complex outburst shapes. Analyzing the basic properties, we reveal a strong correlation between the outburst length and the reached peak flux. As an example, we discuss possible models describing the observed correlation in EXO 2030+375.

  18. New Novae snack point

    CERN Multimedia

    2012-01-01

    Located next to the car park by the flag poles, a few metres from the Main CERN Reception (building 33), a new snack point catered by Novae will open to the public on Wednesday 8 August. More information will be available in the next issue of the Bulletin!

  19. Discovery of a Promissing Candidate of WZ Sge-Type Dwarf Novae, ASAS 160048-4846.2: Evidence for Double-Peaked Humps

    CERN Document Server

    Imada, A; Imada, Akira

    2005-01-01

    We report on time-resolved CCD photometry during the 2005 June outburst of a dwarf nova, ASAS160048-4846.2. The observed light curves unambiguously showed embryonic humps with a period of 0.063381(41) days, after which genuine superhumps emerged with a period of 0.064927(3) days. Based on evidence for double-peaked humps in the earlier stage of the outburst, this object might be qualified as the seventh member of WZ Sge-type dwarf novae after Var Her 04. If the former period is the same as, or very close to the orbital period of the system, as in other WZ Sge systems, the fractional superhump excess is about 2.4${%}$. This value is unexpectedly larger than that of other WZ Sge-type dwarf novae. The early phase of our observing run provided evidence for the transition from chaotic humps to genuine superhumps, together with increasing the amplitude.

  20. Far Ultraviolet Spectroscopy of Old Novae I. V603 Aquila

    CERN Document Server

    Sion, Edward M; Bisol, Alexandra

    2015-01-01

    We present the results of a synthetic spectral analysis of the far ultraviolet archival IUE, HST and FUSE observations of the fast old nova V603 Aql, obtained some 90 years after its 1918 nova outburst. Our analysis utilizes the new Hubble FGS parallax distance for this nearly face-on old nova, a high white dwarf mass and a low reddening. Our analysis includes non-truncated optically thick accretion disks since V603 Aql is neither a polar nor an intermediate polar. Our synthetic spectral modeling of the FUSE and HST spectra analyzed separately indicate a mass transfer rate of 1.5-2.2xe-9 solar mass per year for the FUSE and HST spectra respectively, assuming a WD mass of 1.2Msun. The mass accretion rate also depends on the assumed WD mass, and increases by a factor of two for a WD mass of 0.8Msun. Combining the FUSE and HST spectra together lead to the same results. Potential implications are discussed.

  1. Outbursts from IGR J17473-2721

    Science.gov (United States)

    Zhang, S.; Chen, Y.-P.; Wang, J.-M.; Torres, D. F.; Li, T.-P.

    2009-07-01

    Aims: IGR J17473-2721 was discovered by INTEGRAL as a neutron star low mass X-ray binary. To date, two outbursts have been detected in X-rays by RXTE/ASM and SWIFT: the one occurring in 2005 was weak and was characterized by a low/hard state spectrum; the one of March 2008 was strong and showed a 6-step evolution in its flux. We investigate their evolution, emphasizing the later outburst. Methods: We analyzed all available observations carried out by RXTE on IGR J17473-2721 during its later outburst. We analyzed as well all the available SWIFT/BAT data on this source. Results: The flux of the latter outburst rose in ~one month and then kept roughly constant for the following ~two months. During this time period, the source was in a low/hard state. The source moved to a high/soft state within the following three days, accompanied by the occurrence of an additional outburst at soft X-rays and the end of the preceding outburst in hard X-rays. During the decay of this soft outburst, the source went back to a low/hard state within 6 days, with a luminosity 4 times lower than the first transition. This shows a full cycle of the hysteresis in transition between the hard and the soft states. The fact that the flux remained roughly constant for ~two months at times prior to the spectral transition to a high/soft state might be regarded as the result of balancing the evaporation of the inner disk and the inward accretion flow, in a model in which the state transition is determined by the mass flow rate. Such a balance might be broken via an additional mass flow accreting onto the inner disk, which lightens the extra soft outburst and causes the state transition. However, the possibility of an origin of the emission from the jet during this time period cannot be excluded. The spectral analysis suggests an inclined XRB system for IGR J17473-2721. Such a long-lived preceding low/hard state makes IGR J17473-2721 resemble the behavior of outbursts seen in black hole X

  2. Fermi Reveals New Light on Novae in Gamma rays

    CERN Document Server

    Cheung, C C; Shore, S N; Grove, J E; Leising, M

    2016-01-01

    Novae are now firmly established as a high-energy (>100 MeV) gamma-ray source class by the Fermi Large Area Telescope (LAT). In symbiotic binary systems such as V407 Cyg 2010, there is a firm theoretical framework for the production of shock-accelerated particles in the nova ejecta from interactions with the dense wind of the red giant companion. Yet, the high-energy gamma-ray emission detected in classical novae involving less evolved stellar companions cannot be explained in the same way and could instead be produced in internal shocks in the ejecta. We summarize the Fermi-LAT gamma-ray observations of novae, highlighting the main properties that will guide further studies. Additionally, we report on the soft gamma-ray (~0.1 MeV) continuum detection of the oxygen-neon type classical nova V382 Vel 1999 with the OSSE detector aboard the Compton Gamma Ray Observatory in light of its Fermi-era analog, V959 Mon 2012.

  3. The Galactic Nova Rate Revisited

    CERN Document Server

    Shafter, A W

    2016-01-01

    Despite its fundamental importance, a reliable estimate of the Galactic nova rate has remained elusive. Here, the overall Galactic nova rate is estimated by extrapolating the observed rate for novae reaching $m\\leq2$ to include the entire Galaxy using a two component disk plus bulge model for the distribution of stars in the Milky Way. The present analysis improves on previous work by considering important corrections for incompleteness in the observed rate of bright novae. Several models are considered to account for differences in the assumed properties of bulge and disk nova populations. The simplest models, which assume uniform properties between bulge and disk novae, predict Galactic nova rates between $\\sim$50 to as many as $\\sim$100 per year, depending on the assumed incompleteness at bright magnitudes. Models where the disk novae are assumed to be more luminous than bulge novae are explored, and predict nova rates up to 30% lower, in the range of $\\sim$35 to $\\sim$70 per year. An average of the most p...

  4. V899 Mon: An Outbursting Protostar With Peculiar Light Curve And Its Transition Phases

    CERN Document Server

    Ninan, J P; Baug, T; Bhatt, B C; Mohan, V; Ghosh, S K; Men'shchikov, A; Anupama, G C; Tamura, M; Henning, Th

    2015-01-01

    We present a detailed study of V899 Mon (a new member in the FUors/EXors family of young low-mass stars undergoing outburst), based on our long-term monitoring of the source starting from November 2009 to April 2015. Our optical and near-infrared photometric and spectroscopic monitoring recorded the source transitioning from its first outburst to a short duration quiescence phase ($<$ 1 year), and then returning to a second outburst. We report here the evolution of the outflows from inner region of the disk as the accretion rate evolved in various epochs. Our high resolution (R$\\sim$37000) optical spectrum could resolve interesting clumpy structures in the outflow traced by various lines. Change in far-infrared flux was also detected between two outburst epochs. Based on our observations we constrained various stellar and envelope parameters of V899 Mon, as well as the kinematics of its accretion and outflow. The photometric and spectroscopic properties of this source fall between classical FUors and EXors...

  5. THE RHEOLOGICAL PROPERTIES AND OUTBURST MECHANISM OF GASEOUS COAL

    Institute of Scientific and Technical Information of China (English)

    何学秋; 周世宁; 林柏泉

    1991-01-01

    Coal and methane outburst is one of the harmful disasters in coal mines. We have studied the rheological properties of gaseous coal in laboratory and obtained its rheological fracture principle. This principle can better explain and describe the outburst mechanism of gaseous coal. Thereby a rheological hypothesis of coal and methane outburst is put forward in this paper.

  6. IR study of nova V2468 Cyg from early decline to the coronal phase

    CERN Document Server

    Raj, A; Rudy, Richard J; Russell, Ray W; Lynch, David K; Woodward, Charles E; Sitko, Michael; Day-Wilson, Amanda; Perry, R Brad; KIM, Sang Chul; Pak, Mina

    2015-01-01

    We present infrared spectroscopic and photometric observations of the nova V2468 Cyg covering the period from 2008 March 13 till 2008 November 11. The JHK spectra of the object have been taken from the Mount Abu Infrared Observatory using the Near-Infrared Imager/Spectrometer. Spectra from 0.8-5.2 micron are also presented that were obtained using the NASA Infrared Telescope Facility and the SPEX instrument. The spectra are dominated by strong H I lines from the Brackett and Paschen series, Fe II, OI and CI lines in the initial days, typical of an Fe II type nova. The lines were broader in the period immediately after outburst with measured FWHM of 1800-2300 km/s for the Pa-beta and Br-gamma lines. These values narrowed to 1500-1600 km/s by 12 days from outburst. The spectra showed prominent He I lines at 1.0830 and 2.0581 micron together with H I and O I emission features after 36 days from outburst. Our IR observations show the comparatively broad emission lines, the rapid development of the spectrum to hig...

  7. Vila Nova de Gaia

    OpenAIRE

    Almeida, Salvador de Pinho Ferreira de

    2012-01-01

    The Old Historic Centre of Vila Nova de Gaia is a real living document of the life conditions and construction techniques of ancestral generations representative of cultural values, namely historical, architectural, urbanistic or just emotional that cannot be lost by neglect or carelessness, as they constitute a collective memory. It is necessary to draw attention to the hygienic-sanitary issues (water supply, wastewater disposal, solid urban waste), quality of life (noise, air...

  8. The Radio Light Curve of the Gamma-Ray Nova in V407 CYG: Thermal Emission from the Ionized Symbiotic Envelope, Devoured from Within by the Nova Blast

    Science.gov (United States)

    Chomiuk, Laura; Krauss, Miriam I.; Rupen, Michael P.; Nelson, Thomas; Roy, Nirupam; Sokoloski, Jennifer L.; Mukai, Koji; Munari, Ulisse; Mioduszewski, Amy; Weston, Jeninfer; O'Brien, Tim J.; Eyres, Steward P. S.; Bode, Michael F.

    2012-01-01

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1.45 GHz and 17.770 days following discovery. This nova.the first ever detected in gamma rays.shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grewas the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of .Mw approximately equals 10(exp -6) Solar mass yr(exp -1). We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of 20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  9. The unreasonable effectiveness of experiments in constraining nova nucleosynthesis

    Directory of Open Access Journals (Sweden)

    Parikh Anuj

    2014-01-01

    Full Text Available Classical nova explosions arise from thermonuclear ignition in the envelopes of accreting white dwarfs in close binary star systems. Detailed observations of novae have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. These phenomena are unusual in nuclear astrophysics because most of the thermonuclear reaction rates thought to be involved are constrained by experimental measurements. This situation allows for rather precise statements to be made about which measurements are still necessary to improve the nuclear physics input to astrophysical models. We briefly discuss desired measurements in these environments with an emphasis on recent experimental progress made to better determine key rates.

  10. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VI: The Sixth Year (2013-2014)

    CERN Document Server

    Kato, Taichi; Kudzej, Igor; Hambsch, Franz-Josef; Miller, Ian; Ohshima, Tomohito; Nakata, Chikako; Kawabata, Miho; Nishino, Hirochika; Masumoto, Kazunari; Mizoguchi, Sahori; Yamanaka, Masayuki; Matsumoto, Katsura; Sakai, Daisuke; Fukushima, Daiki; Matsuura, Minami; Bouno, Genki; Takenaka, Megumi; Nakagawa, Shinichi; Noguchi, Ryo; Iino, Eriko; Pickard, Roger D; Maeda, Yutaka; Henden, Arne; Kasai, Kiyoshi; Kiyota, Seiichiro; Akazawa, Hidehiko; Imamura, Kazuyoshi; de Miguel, Enrique; Maehara, Hiroyuki; Monard, Berto; Pavlenko, Elena P; Antonyuk, Kirill; Pit, Nikolaj; Antonyuk, Oksana I; Baklanov, Aleksei V; Ruiz, Javier; Richmond, Michael; Oksanen, Arto; Harlingten, Caisey; Shugarov, Sergey Yu; Chochol, Drahomir; Masi, Gianluca; Nocentini, Francesca; Schmeer, Patrick; Bolt, Greg; Nelson, Peter; Ulowetz, Joseph; Sabo, Richard; Goff, William N; Stein, William; Michel, Raul; Dvorak, Shawn; Voloshina, Irina B; Metlov, Vladimir; Katysheva, Natalia; Neustroev, Vitaly V; Sjoberg, George; Littlefield, Colin; Debski, Bartlomiej; Sowicka, Paulina; Klimaszewski, Marcin; Curylo, Malgorzata; Morelle, Etienne; Curtis, Ivan A; Iwamatsu, Hidetoshi; Butterworth, Neil D; Andreev, Maksim V; Parakhin, Nikolai; Sklyanov, Aleksandr; Shiokawa, Kazuhiko; Novak, Rudolf; Irsmambetova, Tat'yana R; Itoh, Hiroshi; Ito, Yoshiharu; Hirosawa, Kenji; Denisenko, Denis; Kochanek, Christopher S; Shappee, Benjamin; Stanek, Krzysztof Z; Prieto, Jose L; Itagaki, Koh-ichi; Stubbings, Rod; Ripero, Jose; Muyllaert, Eddy; Poyner, Gary

    2014-01-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv:0905.1757), we collected times of superhump maxima for 56 SU UMa-type dwarf novae mainly observed during the 2013-2014 season and characterized these objects. We detected negative superhumps in VW Hyi and indicated that the low number of normal outbursts in some supercycle can be interpreted as a result of the disk tilt. This finding, combined with the Kepler observation of V1504 Cyg and V344 Lyr, suggests that the disk tilt is responsible for modulating the outburst pattern in SU UMa-type dwarf novae. We also studied the deeply eclipsing WZ Sge-type dwarf nova MASTER OT J005740.99+443101.5 and found evidence of a sharp eclipse during the phase of early superhumps. The profile can be reproduced by a combination of the eclipse of the axisymmetric disk and the uneclipsed light source of early superhumps. This finding confirms the lack of evince of a greatly enhanced hot spot during the early stage of WZ Sge-type outburst. We detected g...

  11. Classical antiparticles

    Energy Technology Data Exchange (ETDEWEB)

    Costella, J.P.; McKellar, B.H.J.; Rawlinson, A.A.

    1997-03-01

    We review how antiparticles may be introduced in classical relativistic mechanics, and emphasize that many of their paradoxical properties can be more transparently understood in the classical than in the quantum domain. (authors). 13 refs., 1 tab.

  12. Análises histopatológica e morfométrica no diagnóstico da "nova" displasia broncopulmonar e comparação clinicopatológica com a forma clássica da doença Histopathological and morphometric analysis in the diagnosis of "new" broncopulmonar dysplasia and clinical and pathological comparison with the classic form of the disease

    Directory of Open Access Journals (Sweden)

    Cristina Terumy Okamoto

    2009-04-01

    Full Text Available INTRODUÇÃO: A displasia broncopulmonar (DBP continua sendo a principal complicação nos recém-nascidos (RN prematuros. Com o uso de surfactante exógeno e da prevenção de doenças respiratórias no período neonatal a incidência de DBP clássica vem diminuindo, porém uma nova forma de DBP tem surgido, mais branda e associada aos desenvolvimentos pulmonar alveolar e vascular incompletos. Do ponto de vista anatomopatológico a DBP clássica é caracterizada por processos de lesão e reparação, e os achados da "nova" DBP são de hipoplasia alveolar com nenhuma fibrose. OBJETIVOS: Demonstrar as alterações histopatológicas e morfométricas em pulmões de prematuros que foram a óbito, com quadro clínico compatível com "nova" DBP, comparando-as com um grupo controle (sem DBP e com a forma clássica da doença, além de correlacionar os três grupos com o tempo de uso de oxigênio entre outros fatores de risco da DBP. MATERIAL E MÉTODOS: A população foi composta por 59 amostras de pulmões de prematuros com idade gestacional (IG menor que 34 semanas e submetidos à oxigenioterapia. Fatores de risco para DBP foram coletados por meio da revisão de prontuários. Amostras pulmonares foram separadas em dois grupos, o com DBP clássica e o sem DBP clássica. O segundo grupo foi então submetido à análise morfométrica para contagem do número de alvéolos, medidas as áreas e os perímetros dos alvéolos. Após esta análise a população estudada ficou dividida em grupo com DBP clássica; com "nova" DBP (casos com mais de sete dias de oxigenioterapia; e grupo controle ou sem DBP clássica ou "nova" (casos com menos de sete dias de oxigenioterapia. RESULTADOS: o primeiro grupo apresentava inflamação e fibrose septal evidentes. Já os segundo e terceiro grupos apresentavam alterações histopatológicas mínimas, sendo então necessária a análise morfométrica para separá-los. O grupo com "nova" DBP apresentou número de alv

  13. The 1991-2012 light curve of the old nova HR Lyrae

    Energy Technology Data Exchange (ETDEWEB)

    Honeycutt, R. K. [Astronomy Department, Indiana University, Swain Hall West, Bloomington, IN 47405 (United States); Shears, J. [Bunbury Observatory, Pemberton, School Lane, Bunbury, Tarporley, Cheshire CW6 9NR (United Kingdom); Kafka, S. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Robertson, J. W. [Department of Physical Sciences, Arkansas Tech University, 1701 N. Boulder, Russellville, AR 72801-2222 (United States); Henden, A. A., E-mail: honey@astro.indiana.edu, E-mail: bunburyobservatory@hotmail.com, E-mail: skafka@aip.org, E-mail: Jeff.Robertson@atu.edu, E-mail: arne@aavso.org [American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138-1203 (United States)

    2014-05-01

    The 22 yr light curve of HR Lyr, acquired with a typical cadence of 2-6 days, is examined for periodic and quasi-periodic variations. No persistent periodicities are revealed. Rather, the light curve variations often take the form of nearly linear rises and falls having typical e-folding times of about 100 days. Occasional ∼0.6 mag outbursts are also seen, with properties similar to those of small outbursts found in some nova-like cataclysmic variables. When the photometry is formed into yearly averages, a decline of 0.012 ± 0.005 mag yr{sup –1} is apparent, consistent with the fading of irradiation-induced M-dot following the nova. The equivalent width of Hα is tabulated at three epochs over the interval 1986-2008 in order to compare with a recent result for DK Lac in which Hα was found to be fading 50 yr after the nova. However, our results for such a fading in HR Lyr are inconclusive.

  14. Thermal radio emission from novae & symbiotics with the Square Kilometre Array

    CERN Document Server

    O'Brien, Tim; Chomiuk, Laura; Ribeiro, Valerio; Bode, Michael; Sokoloski, Jennifer; Woudt, Patrick

    2015-01-01

    The thermal radio emission of novae during outburst enables us to derive fundamental quantities such as the ejected mass, kinetic energy, and density profile of the ejecta. Recent observations with newly-upgraded facilities such as the VLA and e-MERLIN are just beginning to reveal the incredibly complex processes of mass ejection in novae (ejections appear to often proceed in multiple phases and over prolonged timescales). Symbiotic stars can also exhibit outbursts, which are sometimes accompanied by the expulsion of material in jets. However, unlike novae, the long-term thermal radio emission of symbiotics originates in the wind of the giant secondary star, which is irradiated by the hot white dwarf. The effect of the white dwarf on the giant's wind is strongly time variable, and the physical mechanism driving these variations remains a mystery (possibilities include accretion instabilities and time-variable nuclear burning on the white dwarf's surface). The exquisite sensitivity of SKA1 will enable us to su...

  15. Pan-Chromatic observations of the Recurrent Nova LMC 2009a (LMC 1971b)

    CERN Document Server

    Bode, M F; Beardmore, A P; Osborne, J P; Page, K L; Walter, F M; Krautter, J; Melandri, A; Ness, J -U; O'Brien, T J; Orio, M; Schwarz, G J; Shara, M M; Starrfield, S

    2016-01-01

    Nova LMC 2009a is confirmed as a Recurrent Nova (RN) from positional coincidence with nova LMC 1971b. The observational data set is one of the most comprehensive for any Galactic or extragalactic RN: optical and near-IR photometry from outburst until over 6 years later; optical spectra for the first 6 months, and Swift satellite Ultraviolet and X-ray observations from 9 days to almost 1 year post-outburst. We find $M_V = -8.4\\pm0.8_{\\mathrm{r}}\\pm0.7_{\\mathrm{s}}$ and expansion velocities between 1000 and 4000 km s$^{-1}$. Coronal line emission before day 9 indicates shocks in the ejecta. Strengthening of He II $\\lambda$4686 preceded the emergence of the Super-Soft Source (SSS) in X-rays at $\\sim63-70$ days, which was initially very variable. Periodic modulations, $P=1.2$ days, most probably orbital in nature, were evident in the UV and optical from day 43. Subsequently, the SSS shows an oscillation with the same period but with a delay of 0.28P. The progenitor system has been identified; the secondary is mos...

  16. Detection and evolution of the CO (v = 2) emission in nova V2615 Ophiuchi (2007)

    CERN Document Server

    Das, Ramkrishna; Ashok, N M

    2009-01-01

    We present near-infrared (1 - 2.5 micron) spectroscopic and photometric results of Nova V2615 Ophiuchi which was discovered in outburst in 2007 March. Our observations span a period of ~ 80 days starting from 2007 March 28 when the nova was at its maximum light. The evolution of the spectra are shown from the initial P-Cygni phase to an emission-line phase and finally to a dust formation stage. The characteristics of the JHK spectra are very similar to those observed in a nova outburst occurring on a carbon-oxygen white dwarf. We analyse an observed line at 2.088 micron and suggest it could be due to FeII excited by Lyman alpha fluorescence. The highlight of the observations is the detection of the first overtone bands of carbon monoxide (CO) in the 2.29 - 2.40 micron region. The CO bands are modeled to estimate the temperature and mass of the emitting CO gas and also to place limits on the 12C/13C ratio. The CO bands are recorded over several epochs thereby allowing a rare opportunity to study its evolution ...

  17. Experimental modelling of outburst flood - bed interactions

    Science.gov (United States)

    Carrivick, J. L.; Xie, Z.; Sleigh, A.; Hubbard, M.

    2009-04-01

    Outburst floods are a sudden release and advancing wave of water and sediment, with a peak discharge that is often several orders of magnitude greater than perennial flows. Common outburst floods from natural sources include those from glacial and moraine-impounded lakes, freshwater dyke and levee bursts, volcanic debris dams, landslides, avalanches, coastal bay-bars, and those from tree or vegetation dams. Outburst flood hazards are regularly incorporated into risk assessments for urban, coastal and mountainous areas, for example. Outburst flood hazards are primarily due to direct impacts, caused by a frontal surge wave, from debris within a flow body, and from the mass and consistency of the flows. A number of secondary impacts also pose hazards, including widespread deposition of sediment and blocked tributary streams. It is rapid landscape change, which is achieved the mobilization and redistribution of sediment that causes one of the greatest hazards due to outburst floods. The aim of this project is therefore to parameterise hydrodynamic - sedimentary interactions in experimental outburst floods. Specifically, this project applies laboratory flume modelling, which offers a hitherto untapped opportunity for examining complex interactions between water and sediment within outburst floods. The experimental set-up is of a tradition lock-gate design with a straight 4 m long tank. Hydraulics are scaled at 1:20 froude scale and the following controls on frontal wave flow-bed interactions and hence on rapid landscape change are being investigated: 1. Pre-existing mobile sediment effects, fixed bed roughness effects, sediment concentration effects, mobile bed effects. An emphasis is being maintained on examining the downstream temporal and spatial change in physical character of the water / sediment frontal wave. Facilities are state-of-the-art with a fully-automated laser bed-profiler to measure bed elevation after a run, Seatek arrays to measure transient flow

  18. NOVAS TECNOLOGIAS NO ENVELHECIMENTO

    Directory of Open Access Journals (Sweden)

    Rosa Maria Farah

    2010-02-01

    Full Text Available O Programa de Estudos Pós-Graduados em Gerontologia/PUC-SP desenvolve pesquisas em diversificadas linhas algumas das quais têm em comum o acolhimento à questão das novas tecnologias no envelhecimento. São investigações de caráter interdisciplinar que envolvem docentes-pesquisadores, orientandos de mestrado e de iniciação científica. Na área da educação a distância, a PUC-SP inaugura um trabalho em que o idoso interessado em avançar em seus conhecimentos é recebido em um ambiente virtual de aprendizagem, em que pode participar de cursos avançados de aquisição de novas linguagens e de navegação na Internet, cujas consequências são o investimento em uma via mais digna para o envelhecer no sentido de esse idoso sentir-se um ser ligado aos novos tempos em que a interatividade digital traz-lhe possibilidades ilimitadas de contatos com o outro, com o mundo enfim. A pesquisa sobre a inclusão cibersocial do idoso mostra o que significa colocar o idoso em contato com a Internet, quando este recebe, por meio das redes sociais, ofertas de várias ordens, e equipamentos que contornam limitações de ordem física ou motora. Além disso, o registro digital da memória do idoso, de sua história e referências também podem constituir conteudos preciosos para pesquisas. A relação do idoso com a informática pode situá-lo como um ator, produtor e reprodutor no ciberespaço. Isso significa que as vantagens do uso do computador fazem o idoso ganhar novo sentido na vida, na medida em que pode assim preencher o vazio causado pelas perdas que lhe vão ocorrendo, possibilitando que ele redimensione seu olhar para o presente e futuro. Palavras-chave: o sujeito-idoso nas novas tecnologias; novas tecnologias e envelhecimento; o idoso na educação a distância; internet na velhice.

  19. Economic Security in Nova Scotia

    OpenAIRE

    Lars Osberg; Andrew Sharpe

    2008-01-01

    The report uses an aggregate index, based on security from the economic risks imposed by four key factors – unemployment, illness, old age, and single parenthood – to examine trends in economic security in Nova Scotia from 1981 to 2007. It concludes that economic security in Nova Scotia decreased during the 1981-2007 period.

  20. The secondary maxima in black hole X-ray nova light curves - Clues toward a complete picture

    Science.gov (United States)

    Chen, Wan; Livio, Mario; Gehrels, Neil

    1993-01-01

    We study the secondary maxima observed commonly in the X-ray/optical light curves of black hole X-ray novae and show that they can play an important role in our understanding of the X-ray nova phenomenon. We discuss the observational characteristics of the secondary maxima and possible mechanisms to produce them. We propose a complete scenario for black hole X-ray nova events. The main outburst is caused by a disk instability. The second maximum is caused by X-ray evaporation of the matter near the inner Lagrangian (L1) region when the disk becomes optically thin. The third maximum (or the final minioutburst) is due to a mass transfer instability caused by hard X-ray heating of the subphotospheric layers of the secondary during the outburst. We predict that the newly discovered X-ray nova GRO J0422 + 32 may develop a final minioutburst in early 1993 and that its binary orbital period is less than 7 hr.

  1. Franchising in Nova Scotia

    International Nuclear Information System (INIS)

    Opportunities for the local distribution of natural gas in Nova Scotia were reviewed, with special emphasis on franchising. Franchising in Nova Scotia began in 1980, made possible by the passage of the Gas Utilities Act and the Pipeline Act which promised western Canadian natural gas to eastern Canada. However, proposals for franchisees to distribute natural gas in the province were abandoned as the hope for natural gas transmission service to the province faded. The plummeting of world oil prices by the mid-1980s was also a contributory factor. Discovery and development of natural gas facilities around Sable Island led to the September 1997 proclamation of the Gas Distribution Act, which also led to the revival of interest in franchising. The Act provides for the competitive marketing of natural gas as a commodity and the regulation of the gas delivery system under a franchise agreement. Competitive applications are expected early in 1998, with awards of franchises in late 1998. Construction and gas delivery services should begin operations late in 1999

  2. V2487 Oph 1998: a post nova in an intermediate polar

    Science.gov (United States)

    Hernanz, Margarita

    2014-01-01

    V2487 Oph (Nova Oph 1998) is a classical nova that exploded in 1998. XMM-Newton observations performed between 2 and 9 years after the explosion showed emission related to restablished accretion, and indicative of a magnetic white dwarf. The spectrum looks like that of a cataclysmic variable of the intermediate polar type. Anyway, we don't have yet a definitive confirmation of the intermediate polar character, through determination of spin and orbital periods. Although it is not the first nova exploding in a magnetic white dwarf, it is always challenging to reach explosive conditions when a standard accretion disk can't be formed, because of the magnetic field. In addition, V2487 Oph has been the first nova where a detection of X-rays - in the host binary system - has been reported prior to its eruption, in 1990 with the ROSAT satellite. V2487 Oph has been also detected in hard X-rays with INTEGRAL/IBIS and RXTE/PCA. Last but not least, V2487 Oph has been identified as a recurrent nova in 2008, since a prior eruption in 1900 has been reported through analysis of Harvard photographic plates. Therefore, it is expected to host a massive white dwarf and be a candidate for a type Ia supernova explosion. In a recent study of the progenitors of galactic novae, it has been emphasized that V2487 Oph is an important and interesting object, "intermediate" between the "standard" classical novae and other historical and well-known recurrent novae with shorter recurrence periods. It could be that in the end there's a continuous distribution of recurrence periods, instead of the common understanding up to now that "classical" and "recurrent" novae were quite apart (with recurrence periods of more than 104 years and less than 100years - approximately - respectively). We present the results of our campaign of several observations with XMM-Newton. The consequences for the understanding of such a puzzling object are discussed.

  3. THE RADIO LIGHT CURVE OF THE GAMMA-RAY NOVA IN V407 CYG: THERMAL EMISSION FROM THE IONIZED SYMBIOTIC ENVELOPE, DEVOURED FROM WITHIN BY THE NOVA BLAST

    International Nuclear Information System (INIS)

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1-45 GHz and 17-770 days following discovery. This nova—the first ever detected in gamma rays—shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grew as the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of M-dotw approx. 10-6 M☉ yr-1. We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of ∼>20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  4. RECURRENT NOVAE IN M31

    International Nuclear Information System (INIS)

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.′1, although this criterion was relaxed to 0.′15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae

  5. Classical integrability

    Science.gov (United States)

    Torrielli, Alessandro

    2016-08-01

    We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin–Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand–Levitan–Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  6. Spitzer Observations of Var Her 04: Possible Detection of Dust Formation in a Super-Outbursting TOAD

    CERN Document Server

    Ciardi, D R; Hoard, D W; Howell, S B; Van Belle, G T; Ciardi, David R.; Wachter, Stefanie; Howell, Steve B.; Belle, Gerard T. van

    2006-01-01

    We present four MIPS (24 \\micron) and two IRAC (3.6, 4.5, 5.8, and 8.0 \\micron) Spitzer observations of the newly discovered Tremendous Outburst Amplitude Dwarf nova (TOAD) Var Her 04 during decline from super-outburst. The four MIPS observations span 271 days and the two IRAC observations span 211 days. Along the line-of-sight to Var Her 04, there is a foreground M-star within 1\\arcsec of the variable; as a result, all of the Spitzer photometry presented in this paper is a blend of the foreground M-star and Var Her 04. We estimate the quiescent level of the TOAD to be $\\Delta V=4-5$ magnitudes below that of the M-star. Based upon the spectral energy distribution and the 2MASS colors, we find the M-star to be an M3.5V dwarf at a distance of 80-130 pc. Based upon its outburst amplitude and quiescent apparent magnitude, we estimate the distance to Var Her 04 to be 200-400 pc, suggesting that the line-of-sight foreground star is physically unrelated to the cataclysmic variable. All of the Spitzer photometry is c...

  7. A prediction of a luminous red nova eruption

    Science.gov (United States)

    Molnar, Lawrence A.; Van Noord, Daniel M.; Steenwyk, Steven D.; Spedden, Chris J.; Kinemuchi, Karen

    2015-01-01

    Luminous red novae have been distinguished as a class of stellar eruption in just the past decade. They are hypothesized to be the result of the merger of two main sequence stars. Tylenda et al. (2011) found remarkable confirmation of this hypothesis by showing that OGLE data preceding the 2008 outburst of V1309 Sco exhibited the light curve of a contact binary system with an orbital period spiraling exponentially down to zero.We will present analysis of light curves of KIC 9832227 (= NSVS 5597755) spanning 15 years that show it is a contact binary system with a negative period derivative and second derivative. The data are taken from the NSVS, WASP, and Kepler surveys, and extended by Calvin Observatory measurements in 2013 and 2014.Fitting the orbital phase timing to the exponential model of Tylenda et al. (2011) provides a satisfactory fit of the entire data set. While we cannot yet conclude the system will follow the model fit, the prediction it makes will soon be easily falsifiable. The model predicts the period derivative will very soon exceed measured values for all other contact binary stars and that the stars should merge sometime between summer 2019 and summer 2022. If the model holds up, this star presents the unprecedented opportunity to perform a set of targeted observations of a luminous red nova progenitor and to follow carefully the course of the merger.Tylenda, R., et al. (2011), AA, 528, A114.

  8. Outbursts in two new cool pulsating DA white dwarfs

    CERN Document Server

    Bell, Keaton J; Montgomery, M H; Fusillo, N P Gentile; Raddi, R; Gaensicke, B T; Winget, D E; Dennihy, E; Gianninas, A; Tremblay, P -E; Chote, P; Winget, K I

    2016-01-01

    The unprecedented extent of coverage provided by Kepler observations recently revealed outbursts in two hydrogen-atmosphere pulsating white dwarfs (DAVs) that cause hours-long increases in the overall mean flux of up to 14%. We have identified two new outbursting pulsating white dwarfs in K2, bringing the total number of known outbursting white dwarfs to four. EPIC 211629697, with T_eff = 10,780 +/- 140 K and log(g) = 7.94 +/- 0.08, shows outbursts recurring on average every 5.0 d, increasing the overall flux by up to 15%. EPIC 229227292, with T_eff = 11,190 +/- 170 K and log(g) = 8.02 +/- 0.05, has outbursts that recur roughly every 2.4 d with amplitudes up to 9%. We establish that only the coolest pulsating white dwarfs within a small temperature range near the cool, red edge of the DAV instability strip exhibit these outbursts.

  9. Study of coal and gas outbursts by numerical modeling approach

    Institute of Scientific and Technical Information of China (English)

    LI Sheng; ZHANG Hong-wei

    2007-01-01

    During mining or road-way development, the distribution of stress and coal pore pressure in the coal face and rib around the new opening will change, under certain conditions, dynamic failure of coal in the form of an outburst can occur. In the modeling studies presented in this paper, an outburst was considered to consist of three distinct stages:preinitiation, initiation and post-initiation, which takes into account the major processes and mechanisms that can influence both outburst-proneness and post-initiation outburst behavior. The model has been applied to simulate the effects of mechanisms in the coal matrix, coal strength, coal damage, geological structures on outbursts. The model constructed using the FLAC software, which were undertaken to research the effects on outbursts of coal strength pressure gradient, and other factors.

  10. SU UMa dwarf novae in the period gap showing the negative superhumps

    Science.gov (United States)

    Pavlenko, Elena

    2016-07-01

    There are only two known up to date SU UMa dwarf novae in the period gap showing the negative superhumps, namely, MN Dra and 1RXS J003828.7+250920. We present the results of X-ray and spectral investigation for 1RXS J003828.7+250920, multicolor optical investigation for 1RXS J003828.7+250920 and MN Dra at different stages of their activity in 2011-2016 years. We discuss a finding of the accretion disc radius for both dwarf novae, its variation during separated intervals between outbursts for MN Dra as well as high and low temperature regions in quiescent accretion disk for 1RXS J003828.7+250920.

  11. Olivier Chesneau's work on novae

    CERN Document Server

    Millour, Florentin

    2016-01-01

    Olivier Chesneau founded a brand new field of observational astrophysics with his attempts to resolve the novae expanding fireball from the very first days of the explosion. With the images he could get, he showed that novae do indeed explode in an aspherical way, leading to a change of paradigm for the physics of these yet-poorly understood catastrophic systems. He also set the stage for a new way of estimating novae distances, by directly measuring the sky-size of the fireball and comparing it with spectroscopic scales, taking into account the tremendous effects of the fireball geometry.

  12. Olivier Chesneau's Work on Novae

    Science.gov (United States)

    Millour, F.; Lagadec, E.

    2015-12-01

    Olivier Chesneau founded a brand new field of observational astrophysics with his attempts to resolve the novae expanding fireball from the very first days of the explosion. With the images he could get, he showed that novae do indeed explode in an aspherical way, leading to a change of paradigm for the physics of these yet-poorly understood catastrophic systems. He also set the stage for a new way of estimating novae distances, by directly measuring the sky-size of the fireball and comparing it with spectroscopic scales, taking into account the tremendous effects of the fireball geometry.

  13. Novae as Tevatrons: prospects for CTA and IceCube

    Science.gov (United States)

    Metzger, B. D.; Caprioli, D.; Vurm, I.; Beloborodov, A. M.; Bartos, I.; Vlasov, A.

    2016-04-01

    The discovery of novae as sources of ˜0.1-1 GeV gamma-rays highlights the key role of shocks and relativistic particle acceleration in these transient systems. Although there is evidence for a spectral cut-off above energies ˜1-100 GeV at particular epochs in some novae, the maximum particle energy achieved in these accelerators has remained an open question. The high densities of the nova ejecta (˜10 orders of magnitude larger than in supernova remnants) render the gas far upstream of the shock neutral and shielded from ionizing radiation. The amplification of the magnetic field needed for diffusive shock acceleration requires ionized gas, thus confining the acceleration process to a narrow photoionized layer immediately ahead of the shock. Based on the growth rate of the hybrid non-resonant cosmic ray current-driven instability (considering also ion-neutral damping), we quantify the maximum particle energy, Emax, across the range of shock velocities and upstream densities of interest. We find values of Emax ˜ 10 GeV-10 TeV, which are broadly consistent with the inferred spectral cut-offs, but which could also in principle lead to emission extending to ≳ 100 GeV accessible to atmosphere Cherenkov telescopes, such as the Cherenkov Telescope Array (CTA). Detecting TeV neutrinos with IceCube is more challenging, although the prospects are improved for a nearby event (≲ kpc) or if the shock power during the earliest, densest phases of the outburst is higher than implied by the GeV light curves, due to downscattering of the gamma-rays within the ejecta.

  14. Time-resolved optical/near-IR polarimetry of V404 Cyg during its 2015 outburst

    CERN Document Server

    Shahbaz, T; Covino, S; Mooley, K; Fender, R P; Rumsey, C

    2016-01-01

    We present optical and near-IR linear polarimetry of V404 Cyg during its 2015 outburst and in quiescence. We obtained time resolved r'-band polarimetry when the source was in outburst, near-IR polarimetry when the source was near quiescence and multiple wave-band optical polarimetry later in quiescence. The optical to near-IR linear polarization spectrum can be described by interstellar dust and an intrinsic variable component. The intrinsic optical polarization, detected during the rise of one of the brightest flares of the outburst, is variable, peaking at 4.5 per cent and decaying to 3.5 per cent. We present several arguments that favour a synchrotron jet origin to this variable polarization, with the optical emission originating close to the jet base. The polarization flare occurs during the initial rise of a major radio flare event that peaks later, and is consistent with a classically evolving synchrotron flare from an ejection event. We conclude that the optical polarization flare represents a jet laun...

  15. Classical Tunneling

    CERN Document Server

    Cohn, A G; Rabinowitz, Mario

    2003-01-01

    A classical representation of an extended body over barriers of height greater than the energy of the incident body is shown to have many features in common with quantum tunneling as the center-of-mass literally goes through the barrier. It is even classically possible to penetrate any finite barrier with a body of arbitrarily low energy if the body is sufficiently long. A distribution of body lengths around the de Broglie wavelength leads to reasonable agreement with the quantum transmission coefficient.

  16. Classical Tunneling

    OpenAIRE

    Cohn, Arthur; Rabinowitz, Mario

    2003-01-01

    A classical representation of an extended body over barriers of height greater than the energy of the incident body is shown to have many features in common with quantum tunneling as the center-of-mass literally goes through the barrier. It is even classically possible to penetrate any finite barrier with a body of arbitrarily low energy if the body is sufficiently long. A distribution of body lengths around the de Broglie wavelength leads to reasonable agreement with the quantum transmission...

  17. Classical Motion

    OpenAIRE

    Mould, Richard A

    2003-01-01

    Preciously given rules allow conscious systems to be included in quantum mechanical systems. There rules are derived from the empirical experience of an observer who witnesses a quantum mechanical interaction leading to the capture of a single particle. In the present paper it is shown that purely classical changes experienced by an observer are consistent with these rules. Three different interactions are considered, two of which combine classical and quantum mechanical changes. The previous...

  18. Matter-elements model and application for prediction of coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    PENG Shou-jian; XU Jiang; TAO Yun-qi; CHENG Ming-jun

    2009-01-01

    The theory and method of extenics were applied to establish classical field mat-ter elements and segment field matter elements for coal and gas outburst. A mat-ter-element model for prediction was established based on five matter-elements, which in-cluded gas pressure, types of coal damage, coal rigidity, initial speed of methane diffusion and in-situ stress. Each index weight was given fairly and quickly through the improved analytic hierarchy process, which need not carry on consistency checks, so accuracy of assessment can be improved.

  19. Experimental study of the 22Ne(p,γ)23Na reaction and its implications for novae scenarios

    International Nuclear Information System (INIS)

    The 22Ne(p,γ)23Na reaction belongs to the catalytic neon-sodium cycle and has an important role in the explosive hydrogen burning. The neon-sodium cycle takes place at temperatures of T = 0.1 - 0.5 GK and is assumed to occur in different astrophysical systems: e.g. in novae, in super novae of type Ia and during the shell-burning of red giant branch stars. The implications of 22Ne(p,γ)23Na and the neon-sodium cycle in a nova scenario have been studied by using the nuclear network code libnucnet at GSI in Darmstadt. A nova is an outburst of matter in a binary system consisting of a white dwarf and a red giant star. It is therefore a representative phenomenon for explosive hydrogen burning. For the calculation of the nucleosynthesis during the nova outburst, the code libnucnet requires the initial mass composition of the novae partners, the temperature and density profiles of the nova explosion and the thermonuclear reaction rates of the participating reactions. In the following, the code determined the flow and the final atomic abundance in the neon-sodium cycle during the entire nova process. Additionally, the influence of the temperature profile of the novae outburst as well as the thermonuclear reaction rate of the 22Ne(p,γ)23Na reaction on the final atomic abundance in the outburst has been studied. A characteristic measure for the reactions in astrophysical environments is the thermonuclear reaction rate. The reaction rate of 22Ne(p,γ)23Na has still strong uncertainties in the temperature range of T = 0.03 - 0.3 GK. These uncertainties are based on insufficient upper limits of the resonance strengths as well as the possible existence of tentative states that are populated in the energy range of Elabp = 30 - 300 keV. The research presented in this thesis is dedicated to the experimental study of the 22Ne(p,γ)23Na reaction for an improved determination of the thermonuclear reaction rate. Furthermore, the implications of 22Ne(p,γ)23Na and the neon

  20. Experimental study of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction and its implications for novae scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, Marie-Luise

    2013-08-01

    The {sup 22}Ne(p,{gamma}){sup 23}Na reaction belongs to the catalytic neon-sodium cycle and has an important role in the explosive hydrogen burning. The neon-sodium cycle takes place at temperatures of T = 0.1 - 0.5 GK and is assumed to occur in different astrophysical systems: e.g. in novae, in super novae of type Ia and during the shell-burning of red giant branch stars. The implications of {sup 22}Ne(p,{gamma}){sup 23}Na and the neon-sodium cycle in a nova scenario have been studied by using the nuclear network code libnucnet at GSI in Darmstadt. A nova is an outburst of matter in a binary system consisting of a white dwarf and a red giant star. It is therefore a representative phenomenon for explosive hydrogen burning. For the calculation of the nucleosynthesis during the nova outburst, the code libnucnet requires the initial mass composition of the novae partners, the temperature and density profiles of the nova explosion and the thermonuclear reaction rates of the participating reactions. In the following, the code determined the flow and the final atomic abundance in the neon-sodium cycle during the entire nova process. Additionally, the influence of the temperature profile of the novae outburst as well as the thermonuclear reaction rate of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction on the final atomic abundance in the outburst has been studied. A characteristic measure for the reactions in astrophysical environments is the thermonuclear reaction rate. The reaction rate of {sup 22}Ne(p,{gamma}){sup 23}Na has still strong uncertainties in the temperature range of T = 0.03 - 0.3 GK. These uncertainties are based on insufficient upper limits of the resonance strengths as well as the possible existence of tentative states that are populated in the energy range of E{sup lab}{sub p} = 30 - 300 keV. The research presented in this thesis is dedicated to the experimental study of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction for an improved determination of the

  1. ``Soft X-ray transient'' outbursts which are not soft

    NARCIS (Netherlands)

    C. Brocksopp; R.M. Bandyopadhyay; R.P. Fender

    2004-01-01

    We have accumulated multiwavelength (X-ray, optical, radio) lightcurves for the eight black hole X-ray binaries which have been observed to enter a supposed `soft X-ray transient' outburst, but remained in the low/hard state throughout the outburst. Comparison of the lightcurve morphologies, spectra

  2. HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis

    CERN Document Server

    Shara, Michael M; Schaefer, Bradley E; Bond, Howard E; Godon, Patrick; Mac Low, Mordecai-Mark; Pagnotta, Ashley; Prialnik, Dina; Sion, Edward M; Toraskar, Jayashree; Williams, Robert E

    2015-01-01

    T Pyxidis is the only recurrent nova surrounded by knots of material ejected in previous outbursts. Following the eruption that began on 2011 April 14.29, we obtained seven epochs (from 4 to 383 days after eruption) of Hubble Space Telescope narrowband Ha images of T Pyx . The flash of radiation from the nova event had no effect on the ejecta until at least 55 days after the eruption began. Photoionization of hydrogen located north and south of the central star was seen 132 days after the beginning of the eruption. That hydrogen recombined in the following 51 days, allowing us to determine a hydrogen atom density of at least 7e5 cm^-3 - at least an order of magnitude denser than the previously detected, unresolved [NII] knots surrounding T Pyx. Material to the northwest and southeast was photoionized between 132 and 183 days after the eruption began. 99 days later that hydrogen had recombined. Both then (282 days after outburst) and 101 days later, we detected almost no trace of hydrogen emission around T Pyx...

  3. The first confirmed superoutburst of the dwarf nova GALEX J215818.5+241924

    CERN Document Server

    Shears, Jeremy; Masi, Gianluca; de Miguel, Enrique; Miller, Ian; Roberts, George; Sabo, Richard; Stein, William; Ulowetz, Joseph

    2012-01-01

    GALEX J215818.5+241924 was initially identified as a possible nova in Pegasus. We report unfiltered photometry of the object which revealed the presence of superhumps, with peak-to-peak amplitude of up to 0.22 magnitudes, diagnostic of it being a member of the SU UMa family of dwarf novae. The outburst amplitude was 4.3 magnitudes and it lasted at least 10 days, with a maximum brightness of magnitude 14.3. We determined the mean superhump period from our first 5 nights of observations as Psh = 0.06728(21) d. However analysis of the O-C residuals showed a dramatic evolution in Psh during the outburst. During the first part of the plateau phase the period increased with dPsh/dt = +2.67(15) \\times 10-4. There was then an abrupt change following which the period decreased with dPsh/dt = -2.08(9)\\times10-4. We found a signal in the power spectrum of the photometry which we interpret as the orbital signal with Porb = 0.06606(35) d. Thus the superhump period excess was epsilon = 0.020(8), such value being consistent...

  4. High-resolution spectroscopy and high-density monitoring in X-rays of Novae

    CERN Document Server

    Ness, Jan-Uwe

    2012-01-01

    The 21st century X-ray observatories XMM-Newton, Chandra, and Swift gave us completely new insights into the X-ray behaviour of nova outbursts. These new-generation X-ray observatories provide particularly high spectral resolution and high density in monitoring campaigns, simultaneously in X-rays and UV/optical. The entire evolution of several nova outbursts has been observed with the Swift XRT and UVOT instruments, allowing studies of the gradual shift of the peak of the SED from UV to X-rays, time scales to the onset and duration of the X-ray brightest supersoft source (SSS) phase, and pre- and post-SSS X-ray emission. In addition, XMM-Newton and Chandra observations can efficiently be scheduled, allowing deeper studies of strategically chosen evolutionary stages. Before Swift joined in 2005, Chandra and XMM-Newton blind shots in search of SSS emission unavoidably led to some underexposed observations taken before and/or after the SSS phase. More systematic Swift studies reduced this number while increasing...

  5. Classical Motion

    CERN Document Server

    Mould, R A

    2003-01-01

    Preciously given rules allow conscious systems to be included in quantum mechanical systems. There rules are derived from the empirical experience of an observer who witnesses a quantum mechanical interaction leading to the capture of a single particle. In the present paper it is shown that purely classical changes experienced by an observer are consistent with these rules. Three different interactions are considered, two of which combine classical and quantum mechanical changes. The previously given rules support all of these cases. Key Words: brain states, conscious observer, detector, measurement, probability current, state reduction, von Neumann, wave collapse.

  6. The Impact of FU Orionis Outbursts and the Solar Nebula

    Science.gov (United States)

    Bell, Robbins; Young, Richard E. (Technical Monitor)

    1998-01-01

    Protostellar systems are variable on many timescales. One of the most dramatic forms of variability known to occur in low mass stellar systems is the FU Orionis outburst (Herbig 1977). Throughout a typical outburst lasting several decades, system luminosities may be a hundred times what is typical of the quiesent state. FU Orionis outburst events are thought to have significant impact on the thermal structure of the protosolar nebula; their existence has been used to explain features in the meteoritic record from thermally induced homogenization to the formation of chondrules. Until recently, the magnitude of the likely effect from such outbursts has been largely speculative due to the lack of a detailed understanding of the outburst mechanism. Recent numerical models (Bell\\& Lin 1994) have demonstrated the viability of the observational hypothesis (Hartmann\\& Kenyon 1985) that the radiation observed during outburst is emitted by a luminous circumstellar disk transporting mass at a thousand times the quiesent rate. Light curves and color and line width evolution observed in FU Orionis systems are naturally explained by time dependent outbursting model disks (Bell et al. 1995). The radial temperature structure and shape of the disk during outburst derived from these models may be used to calculate the outburst's expected impact on primitive material at various radii throughout the disk. In this review, we will begin by discussing what is known about the FU Orionis outburst phenomenon from recent observations and theory including statistically deduced outburst timescales and observed peak temperatures. Unless covered by another author, we will discuss the evidence which suggests that outburst radiation is emitted by a circumstellar disk rather than by the star and will briefly review the thermal instability as a mechanism for outburst. We will then report on recent work which investigates the likely heating of solar nebula material due to FU Orionis outbursts

  7. On the origin of the HLX-1 outbursts

    CERN Document Server

    Sun, Mouyuan; Yan, Zhen; Wu, Qingwen; Liu, Tong

    2016-01-01

    HLX-1, currently the best intermediate-mass black hole candidate, has undergone seven violent outbursts, each with a peak X-ray luminosity of $L_{\\mathrm{peak},\\mathrm{X}}\\sim 10^{42}\\ \\rm{erg\\ s^{-1}}$. Interestingly, the properties of the HLX-1 outbursts evolve with time. In this work, we aim to constrain the physical parameters of the central engine of the HLX-1 outbursts in the framework of the black hole accretion. We find that the physical properties of the HLX-1 outbursts are consistent with being driven by the radiation pressure instability. This scenario can explain the evolution of the recurrent timescales of the HLX-1 outbursts as a function of the durations.

  8. Radon monitoring for the prediction of mine outbursts

    International Nuclear Information System (INIS)

    Observations of changes of concentrations of radon in gases occurring in coal seams prone to instantaneous outbursts of coal and gas have been performed. Gas samples have been taken from specially drilled boreholes. In coal seams prone to outbursts strong variations of radon concentration have been found, while in seams where no outbursts occurred radon concentration was much more stable. In all cases outbursts were always preceded by very low concentrations of radon, which raised again afterwards. Similar observations are performed in coal mines where a strong hazard of shocks accompanied by rock bursts occur which is caused by mining activity. Obtained results indicate the possibility of using radon as supporting indicator for prediction of instantaneous outbursts and rock bursts and may be worth-while for prevention of these catastrophes. (author). 9 refs, 2 figs

  9. V5852 Sgr: an unusual nova possibly associated with the Sagittarius stream

    Science.gov (United States)

    Aydi, E.; Mróz, P.; Whitelock, P. A.; Mohamed, S.; Wyrzykowski, Ł.; Udalski, A.; Vaisanen, P.; Nagayama, T.; Dominik, M.; Scholz, A.; Onozato, H.; Williams, R. E.; Hodgkin, S. T.; Nishiyama, S.; Yamagishi, M.; Smith, A. M. S.; Ryu, T.; Iwamatsu, A.; Kawamata, I.

    2016-09-01

    We report spectroscopic and photometric follow-up of the peculiar nova V5852 Sgr (discovered as OGLE-2015-NOVA-01), which exhibits a combination of features from different nova classes. The photometry shows a flat-topped light curve with quasi-periodic oscillations, then a smooth decline followed by two fainter recoveries in brightness. Spectroscopy with the Southern African Large Telescope shows first a classical nova with an Fe II or Fe II b spectral type. In the latter spectrum, broad emissions from helium, nitrogen and oxygen are prominent, and the iron has faded which could be an indication to the start of the nebular phase. The line widths suggest ejection velocities around 1000 km s-1. The nova is in the direction of the Galactic bulge and is heavily reddened by an uncertain amount. The V magnitude 16 days after maximum enables a distance to be estimated and this suggests that the nova may be in the extreme trailing stream of the Sagittarius dwarf spheroidal galaxy. If so it is the first nova to be detected from that, or from any dwarf spheroidal galaxy. Given the uncertainty of the method and the unusual light curve we cannot rule out the possibility that it is in the bulge or even the Galactic disk behind the bulge.

  10. THE TRANSIENT MOLECULAR ENVELOPE IN THE OUTFLOW OF THE NOVA V2676 Oph DURING ITS EARLY PHASE

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, M.; Arai, A.; Kajikawa, T.; Kawakita, H.; Kitao, E.; Arasaki, T.; Taguchi, G.; Ikeda, Y. [Kyoto Sangyo University, Koyama Astronomical Observatory, Motoyama, Kamigamo, Kita, Kyoto 603-8555 (Japan)

    2014-01-10

    Novae are generally considered to be ''hot'' astronomical objects which show effective temperatures of 10,000 K or higher at their visual maximum. However, theoretical predictions suggest that the outer envelope of the nova outflow can become cool enough to form molecules which would be dissociated at such high temperatures. We detected strong C{sub 2} and CN absorption bands in the optical spectrum of the nova V2676 Oph, a very slow nova with dust formation. This is the first report of the detection of C{sub 2,} and the second of CN, in novae during an outburst. Although, based on previous studies, such simple molecules are predicted form in the envelope of the outflow, there are few reports of their detection thus far. The presence of the molecular envelope is considered to be very transient, with a duration of only a few days, in the case of V2676 Oph.

  11. Classical entanglement

    OpenAIRE

    Danforth, Douglas G.

    2001-01-01

    Classical systems can be entangled. Entanglement is defined by coincidence correlations. Quantum entanglement experiments can be mimicked by a mechanical system with a single conserved variable and 77.8% conditional efficiency. Experiments are replicated for four particle entanglement swapping and GHZ entanglement.

  12. Classical Mechanics

    OpenAIRE

    Gallavotti, Giovanni

    1999-01-01

    This is the English version of a friendly graduate course on Classical Mechanics, containing about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. For the Spanish version, see physics/9906066

  13. Shocks in nova outflows. II. Synchrotron radio emission

    CERN Document Server

    Vlasov, Andrey Dmitrievich; Metzger, Brian David

    2016-01-01

    The discovery of GeV gamma-rays from classical novae indicates that shocks and relativistic particle acceleration are energetically key in these events. Further evidence for shocks comes from thermal keV X-ray emission and an early peak in the radio light curve on a timescale of months with a brightness temperature which is too high to result from freely expanding photo-ionized gas. Paper I developed a one dimensional model for the thermal emission from nova shocks. This work concluded that the shock-powered radio peak cannot be thermal if line cooling operates in the post-shock gas at the rate determined by collisional ionization equilibrium. Here we extend this calculation to include non-thermal synchrotron emission. Applying our model to three classical novae, we constrain the amplification of the magnetic field $\\epsilon_B$ and the efficiency $\\epsilon_e$ of accelerating relativistic electrons of characteristic Lorentz factor $\\gamma \\sim 100$. If the shocks are radiative (low velocity $v_{\\rm sh} \\lesssi...

  14. Outbursts in ultracompact X-ray binaries

    CERN Document Server

    Hameury, J -M

    2016-01-01

    Very faint X-ray binaries appear to be transient in many cases with peak luminosities much fainter than that of usual soft X-ray transients, but their nature still remains elusive. We investigate the possibility that this transient behaviour is due to the same thermal/viscous instability which is responsible for outbursts of bright soft X-ray transients, occurring in ultracompact binaries for adequately low mass-transfer rates. More generally, we investigate the observational consequences of this instability when it occurs in ultracompact binaries. We use our code for modelling the thermal-viscous instability of the accretion disc, assumed here to be hydrogen poor. We also take into account the effects of disc X-ray irradiation, and consider the impact of the mass-transfer rate on the outburst brightness. We find that one can reproduce the observed properties of both the very faint and the brighter short transients (peak luminosity, duration, recurrence times), provided that the viscosity parameter in quiesce...

  15. CCD photometry of outbursts in GK Per

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Velič, Z.

    Melville : American Institute of Physics, 2001 - (White, N.; Malaguti, G.; Palumbo, G.), s. 939-942 [X-ray astronomy. Stellar endpoints, AGN, and the diffuse background. Bologna (IT), 06.09.1999-10.09.1999] R&D Projects: GA MŠk ME 137 Institutional research plan: CEZ:AV0Z1003909 Keywords : close binaries * circumstellar matter * novae * cataclysmic variables Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. Forecast and prevention of coal and gas outbursts in the case of application of a new mining method - drilling of a coal pillar

    International Nuclear Information System (INIS)

    Coal and gas outbursts are one of risk factors accompanying the mining of coal in low seams in the Ostrava-Karvina Coalfield. At the use of the method of longwall mining, all coal reserves have not been mined out owing to tectonic faults. For mining out the residual reserves, the application of a new mining method - drilling of a coal pillar was proposed. The method of mining of a coal seam utilizing long large diameter boreholes is verified in the Paskov Mine (company OKD, JSC - Czech Republic) under conditions of rock mass with hazard of rock and gas outbursts in localities of residual pillars left in seams after finishing the mining operations performed with using the classical method of longwall working along the strike. Forecast and preventive measures applied to the verification of the new method were based on previous experience with the mining of seams with hazard of coal and gas outbursts. They accepted fully valid legislation, i.e. Ordinance of Ostrava Regional Mining Authority No. 3895/2002 and supplementary materials (Instructions and Guidelines). The proposed measures respected the character of the method being verified. For all areas being mined, projects containing also chapters specifying the problems of ensuring the safety of mining works and operation under conditions of hazard of coal and gas outbursts were prepared. In the contributions, basic proposals for the principles of coal and gas outburst forecast and prevention when applying the new mining method - drilling of a coal pillar are presented. (authors)

  17. YOUNG AGN OUTBURST RUNNING OVER OLDER X-RAY CAVITIES

    International Nuclear Information System (INIS)

    Although the energetic feedback from active galactic nuclei (AGNs) is believed to have a profound effect on the evolution of galaxies and clusters of galaxies, details of AGN heating remain elusive. Here, we study NGC 193—a nearby lenticular galaxy—based on X-ray (Chandra) and radio (Very Large Array and Giant Meter-wave Radio Telescope) observations. These data reveal the complex AGN outburst history of the galaxy: we detect a pair of inner X-ray cavities, an outer X-ray cavity, a shock front, and radio lobes extending beyond the inner cavities. We suggest that the inner cavities were produced ∼78 Myr ago by a weaker AGN outburst, while the outer cavity, the radio lobes, and the shock front are due to a younger (13-26 Myr) and 4-8 times more powerful outburst. Combining this with the observed morphology of NGC 193, we conclude that NGC 193 likely represents the first example of a second, more powerful, AGN outburst overrunning an older, weaker outburst. These results help us to understand how the outburst energy is dissipated uniformly in the core of galaxies, and therefore may play a crucial role in resolving how AGN outbursts suppress the formation of large cooling flows at cluster centers

  18. HUBBLE SPACE TELESCOPE FAR ULTRAVIOLET SPECTROSCOPY OF THE RECURRENT NOVA T PYXIDIS

    International Nuclear Information System (INIS)

    With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few ∼10–5 M ☉ to 3.3 × 10–4 M ☉, and assuming a mass accretion rate of 10–8-10–7 M ☉ yr–1 for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B – V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ E(B – V) ≤ 0.50) and white dwarf mass (0.70 M ☉ ≤ M wd ≤ 1.35 M ☉) the accreted mass is larger than the ejected mass. Only for a low reddening (∼0.25 and smaller) combined with a large white dwarf mass (0.9 M ☉ and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening

  19. Shocks in nova outflows. II. Synchrotron radio emission

    Science.gov (United States)

    Vlasov, Andrey; Vurm, Indrek; Metzger, Brian D.

    2016-08-01

    The discovery of GeV gamma-rays from classical novae indicates that shocks and relativistic particle acceleration are energetically key in these events. Further evidence for shocks comes from thermal keV X-ray emission and an early peak in the radio light curve on a timescale of months with a brightness temperature which is too high to result from freely expanding photo-ionized gas. Paper I developed a one dimensional model for the thermal emission from nova shocks. This work concluded that the shock-powered radio peak cannot be thermal if line cooling operates in the post-shock gas at the rate determined by collisional ionization equilibrium. Here we extend this calculation to include non-thermal synchrotron emission. Applying our model to three classical novae, we constrain the amplification of the magnetic field ɛB and the efficiency ɛe of accelerating relativistic electrons of characteristic Lorentz factor γ ˜ 100. If the shocks are radiative (low velocity v_sh ≲ 1000 km s-1) and cover a large solid angle of the nova outflow, as likely characterize those producing gamma-rays, then values of ɛe ˜ 0.01 - 0.1 are required to achieve the peak radio brightness for ɛB = 10-2. Such high efficiencies exclude secondary pairs from pion decay as the source of the radio-emitting particles, instead favoring the direct acceleration of electrons at the shock. If the radio-emitting shocks are instead adiabatic (high velocity), as likely characterize those responsible for the thermal X-rays, then much higher brightness temperatures are possible, allowing the radio-emitting shocks to cover a smaller outflow solid angle.

  20. Pattern Recognition and Forecast of Coal and Gas Outburst

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Coal and gas outburst is a complicated dynamic phenomenon in coal mines, Multi-factor Pattern Recognition is based on the relevant data obtained from research achievements of Geo-dynamic Division, With the help of spatial data management, the Neuron Network and Cluster algorithm are applied to predict the danger probability of coal and gas outburst in each cell of coal mining district. So a coal-mining district can be divided into three areas: dangerous area, minatory area, and safe area. This achievement has been successfully applied for regional prediction of coal and gas outburst in Huainan mining area in China.

  1. Nova Scotia's offshore royalty regime

    International Nuclear Information System (INIS)

    Oil production from the Hibernia project in Newfoundland's offshore began in December 1997. It is estimated that by 2010 some 30 per cent of Canada's light oil production and as much as 5-10 per cent of its natural gas production will originate from offshore Newfoundland and Nova Scotia. The current level of investment in east coast offshore petroleum developments is the result of the magnitude of discovered and undiscovered petroleum resources in the region. Advances in offshore petroleum technology also contributed to lower development costs. Another reason for increased investment has been an efficient and predictable regulatory environment and government policies. Nova Scotia's royalty regimes and the evolution of royalty regimes for the Sable Offshore Energy project were discussed. The Offshore Petroleum Royalty Act gives Nova Scotia the ability to establish a royalty regime through regulations, or to enter into royalty agreements on a project by project basis, or to use a mix of both agreement and regulation. The philosophy underlying Nova Scotia's royalty regime is to find the right balance between industry and government's share of project revenues

  2. Photometric study of DWARF novae

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, J.; Jones, D.

    1983-01-01

    A catalogue of UBVRI photoelectric photometry of dwarf novae available in the literature is presented. A comparison with theoretical colour-colour diagrams from steady state discs is made. A correlation of V magnitude with the depth of the Balmer discontinuity is discussed.

  3. Status for CASA NOVA konsortiet

    DEFF Research Database (Denmark)

    Bonke, Sten

    1997-01-01

    The report reviews the development projects and the results hitherto achieved by the design and build organisation CASA NOVA which is one of four consortia within the R&D programme "Process and Product Development in Building", financed by the Ministry of Industry and the Ministry of Housing....

  4. KIC 7524178 -- an SU UMa-Type Dwarf Nova Showing Predominantly Negative Superhumps throughout Supercycle

    CERN Document Server

    Kato, Taichi

    2013-01-01

    We analyzed the Kepler long cadence data of KIC 7524178 (=KIS J192254.92+430905.4), and found that it is an SU UMa-type dwarf nova with frequent normal outbursts. The signal of the negative superhump was always the dominant one even during the superoutburst, in contrast to our common knowledge about superhumps in dwarf novae. The signal of the positive superhump was only transiently seen during the superoutburst, and it quickly decayed after the superoutburst. The frequency variation of the negative superhump was similar to the two previously studied dwarf novae in the Kepler field, V1504 Cyg and V344 Lyr. This is the first object in which the negative superhumps dominate throughout the supercycle. Nevertheless, the superoutburst was faithfully accompanied by the positive superhump, indicating that the tidal eccentric instability is essential for triggering a superoutburst. All the pieces of evidence strengthen the thermal-tidal instability as the origin of the superoutburst and supercycle, making this object...

  5. A planetary nebula around nova V458 Vul undergoing flash ionization

    CERN Document Server

    Wesson, R; Corradi, R L M; Drew, J E; Groot, P J; Knigge, C; Steeghs, D; Gänsicke, B T; Napiwotzki, R; Rodríguez-Gil, P; Zijlstra, A A; Bode, M F; Drake, J J; Frew, D J; González-Solares, E A; Greimel, R; Irwin, M J; Morales-Rueda, L; Nelemans, G; Parker, Q A; Sale, S E; Sokoloski, J L; Somero, A; Uthas, H; Walton, N A; Warner, B; Watson, C A; Wright, N J

    2008-01-01

    Nova V458 Vul erupted on 2007 August 8th and reached a visual magnitude of 8.1 a few days later. H$\\alpha$ images obtained six weeks before the outburst as part of the IPHAS galactic plane survey reveal an 18th magnitude progenitor surrounded by an extended nebula. Subsequent images and spectroscopy of the nebula reveal an inner nebular knot increasing rapidly in brightness due to flash ionization by the nova event. We derive a distance of 13 kpc based on light travel time considerations, which is supported by two other distance estimation methods. The nebula has an ionized mass of 0.2 M$_{\\odot}$ and a low expansion velocity: this rules it out as ejecta from a previous nova eruption, and is consistent with it being a ~14,000 year old planetary nebula, probably the product of a prior common envelope (CE) phase of evolution of the binary system. The large derived distance means that the mass of the erupting WD component of the binary is high. We identify two possible evolutionary scenarios, in at least one of ...

  6. Look at Epilepsy: Electrical Outbursts in the Brain

    Science.gov (United States)

    ... our exit disclaimer . Subscribe A Look at Epilepsy Electrical Outbursts in the Brain When you hear the ... epilepsy. Prevent head injuries by wearing seatbelts and bicycle helmets, and make sure kids are properly secured ...

  7. HST Observations of GRO J1655-40 in Outburst

    OpenAIRE

    Hynes, R.I.

    1998-01-01

    We examine the results of a coordinated HST-RXTE-CGRO campaign to study the microquasar GRO J1655-40 during its 1996-7 outburst, focusing on interpretation of the overall anti-correlation seen between optical and X-ray fluxes during the early months of the outburst. Our tools include echo-mapping, optical/UV continuum spectral modelling and analysis of spectral variability. We conclude by suggesting one possible interpretation for the anti-correlation.

  8. V5852 Sgr: An Unusual Nova Possibly Associated with the Sagittarius Stream

    CERN Document Server

    Aydi, E; Whitelock, P A; Mohamed, S; Wyrzykowski, Ł; Udalski, A; Vaisanen, P; Nagayama, T; Dominik, M; Scholz, A; Onozato, H; Williams, R E; Hodgkin, S T; Nishiyama, S; Yamagishi, M; Smith, A M S; Ryu, T; Iwamatsu, A; Kawamata, I

    2016-01-01

    We report spectroscopic and photometric follow-up of the peculiar nova V5852~Sgr (discovered as OGLE-2015-NOVA-01), which exhibits a combination of features from different nova classes. The photometry shows a flat-topped light curve with quasi-periodic oscillations, then a smooth decline followed by two fainter recoveries in brightness. Spectroscopy with the Southern African Large Telescope shows first a classical nova with an Fe II or Fe IIb spectral type. In the later spectrum, broad emissions from helium, nitrogen and oxygen are prominent and the iron has faded which could be an indication to the start of the nebular phase. The line widths suggest ejection velocities around $1000\\,{\\rm km\\,s^{-1}}$. The nova is in the direction of the Galactic bulge and is heavily reddened by an uncertain amount. The $V$ magnitude 16 days after maximum enables a distance to be estimated and this suggests that the nova may be in the extreme trailing stream of the Sagittarius dwarf spheroidal galaxy. If so it is the first no...

  9. The Contribution of Chemical Abundances in Nova Ejecta to the Interstellar Medium

    CERN Document Server

    Li, Fanger; Lu, Guoliang; Wang, Zhaojun

    2016-01-01

    According to the nova model from \\citet{Yaron2005} and \\citet{Jose1998} and using Monte Carlo simulation method, we investigate the contribution of chemical abundances in nova ejecta to the interstellar medium (ISM) of the Galaxy. We find that the ejected mass by classical novae (CNe) is about $2.7\\times10^{-3}$ $ \\rm M_\\odot\\ {\\rm yr^{-1}}$. In the nova ejecta, the isotopic ratios of C, N and O, that is, $^{13}$C/$^{12}$C, $^{15}$N/$^{14}$N and $^{17}$O/$^{16}$O, are higher about one order of magnitude than those in red giants. We estimate that about 10$\\%$, 5$\\%$ and 20$\\%$ of $^{13}$C, $^{15}$N and $^{17}$O in the ISM of the Galaxy come from nova ejecta, respectively. However, the chemical abundances of C, N and O calculated by our model can not cover all of observational values. This means that there is still a long way to go for understanding novae.

  10. The contribution of chemical abundances in nova ejecta to the interstellar medium

    Science.gov (United States)

    Li, Fanger; Zhu, Chunhua; Lü, Guoliang; Wang, Zhaojun

    2016-06-01

    According to the nova model from Yaron et al. (2005, ApJ, 418, 794) and José and Hernanz (1998, ApJ, 494, 680), and using a Monte Carlo simulation method, we investigate the contribution of chemical abundances in nova ejecta to the interstellar medium (ISM) of the Galaxy. We find that the mass ejected from classical novae is about 2.7 × 10-3 M⊙ yr-1. In the nova ejecta, the isotopic ratios of C, N, and O, that is, 13C/12C, 15N/14N, and 17O/16O, are higher by about one order of magnitude than those in red giants. We estimate that about 10%, 5%, and 20% of 13C, 15N, and 17O in the ISM of the Galaxy come from nova ejecta, respectively. However, the chemical abundances of C, N, and O calculated by our model cannot cover all observational values. This means that there is still a long way to go to understand novae.

  11. Classical tachyons

    International Nuclear Information System (INIS)

    A review of tachyons, with particular attention to their classical theory, is presented. The extension of Special Relativity to tachyons in two dimensional is first presented, an elegant model-theory which allows a better understanding also of ordinary physics. Then, the results are extended to the four-dimensional case (particular on tachyon mechanics) that can be derived without assuming the existence of Super-luminal reference-frames. Localizability and the unexpected apparent shape of tachyonic objects are discussed, and it is shown (on the basis of tachyon kinematics) how to solve the common causal paradoxes. In connection with General Relativity, particularly the problem of the apparent superluminal expansions in astrophysics is reviewed. The problem (still open) of the extension of relativitic theories to tachyons in four dimensions is tackled, and the electromagnetic theory of tachyons, a topic that can be relevant also for the experimental side, is reviewed. (Author)

  12. Outbursts In Symbiotic Binaries (FUSE 2000)

    Science.gov (United States)

    Kenyon, Scott J.; Sonneborn, George (Technical Monitor)

    2002-01-01

    During the past year, we made good progress on analysis of FUSE observations of the symbiotic binary Z And. For background, Z And is a binary system composed of a red giant and a hot component of unknown status. The orbital period is roughly 750 days. The hot component undergoes large-scale eruptions every 10-20 yr. An outburst began several years ago, triggering this FUSE opportunity. First, we obtained an excellent set of ground-based optical data in support, of the FUSE observations. We used FAST, a high throughput low resolution spectrograph on the 1.5-m telescope at Mt. Hopkins, Arizona. A 300 g/ mm grating blazed at 4750 A, a 3 in. slit, and a thinned Loral 512 x 2688 CCD gave us spectra covering 3800-7500 A at a resolution of 6 A. The wavelength solution for each spectrum has a probable error of +/- 0.5 A or better. Most of the resulting spectra have moderate signal-to-noise, S/.N approx. greater than 30 per pixel. The time coverage for these spectra is excellent. Typically, we acquired spectra every 1-2 nights during dark runs at Mt. Hopkins. These data cover most of the rise and all of the decline of the recent outburst. The spectra show a wealth of emission lines, including H I, He I, He II, [Fe V11], and the Raman scattering bands at 6830 A and 7088 A. The Raman bands and other high ionization features vary considerably throughout the outburst. These features will enable us to correlate variations in the FUSE spectra with variations in the optical spectra. Second, we began an analysis of FUSE spectra of Z And. We have carefully examined the spectra, identifying real features and defects. We have identified and measured fluxes for all strong emission lines, including the O VI doublet at 1032 A and 1038 A. These and several other strong emission lines display pronounced P Cygni absorption components indicative of outgrowing gas. We will attempt to correlate these velocities with similar profiles observed on optical spectra. The line velocities - together

  13. V2487 Oph 1998: a post nova in an intermediate polar

    Directory of Open Access Journals (Sweden)

    Hernanz Margarita

    2014-01-01

    Full Text Available V2487 Oph (Nova Oph 1998 is a classical nova that exploded in 1998. XMM-Newton observations performed between 2 and 9 years after the explosion showed emission related to restablished accretion, and indicative of a magnetic white dwarf. The spectrum looks like that of a cataclysmic variable of the intermediate polar type. Anyway, we don’t have yet a definitive confirmation of the intermediate polar character, through determination of spin and orbital periods. Although it is not the first nova exploding in a magnetic white dwarf, it is always challenging to reach explosive conditions when a standard accretion disk can’t be formed, because of the magnetic field. In addition, V2487 Oph has been the first nova where a detection of X-rays - in the host binary system – has been reported prior to its eruption, in 1990 with the ROSAT satellite. V2487 Oph has been also detected in hard X-rays with INTEGRAL/IBIS and RXTE/PCA. Last but not least, V2487 Oph has been identified as a recurrent nova in 2008, since a prior eruption in 1900 has been reported through analysis of Harvard photographic plates. Therefore, it is expected to host a massive white dwarf and be a candidate for a type Ia supernova explosion. In a recent study of the progenitors of galactic novae, it has been emphasized that V2487 Oph is an important and interesting object, "intermediate" between the "standard" classical novae and other historical and well-known recurrent novae with shorter recurrence periods. It could be that in the end there’s a continuous distribution of recurrence periods, instead of the common understanding up to now that "classical" and "recurrent" novae were quite apart (with recurrence periods of more than 104 years and less than 100years - approximately - respectively. We present the results of our campaign of several observations with XMM-Newton. The consequences for the understanding of such a puzzling object are discussed.

  14. Possible Nova in M31

    Science.gov (United States)

    Burwitz, V.; Pietsch, W.; Updike, A.; Hartmann, D.; Milne, P.; Williams, G.

    2007-10-01

    We report the discovery of an optical nova candidate in M 31 on two 4*60sec stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) Livermore Optical Transient Imaging System (Super- LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2007 Oct 13.255, 13.259 with respective magnitudes of 18.0, 17.8. The position for the nova candidate is RA = 00h43m29.48s, Dec(2000) = +41d17'13.5" (J2000, accuracy of 0.2"), which is 8' 29" east and 1' 5" north of the core of M 31.

  15. The nova-like variables

    CERN Document Server

    Dhillon, V S

    1995-01-01

    We review optical observations and theoretical models of the non-magnetic nova-like variables (UX UMa, VY Scl and SW Sex stars). A brief discussion of the classification scheme is followed by a statistical overview of the observed properties. The most important features of each of the sub-classes are then reviewed, concluding with a summary of the theoretical models invoked to understand these systems.

  16. CK Vul: a smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides)

    CERN Document Server

    Evans, A; Woodward, C E; Sarre, P J; van Loon, J Th; Helton, L A; Starrfield, S; Eyres, S P S

    2015-01-01

    We present observations of CK Vul obtained with the Spitzer Space Telescope. The infrared spectrum reveals a warm dust continuum with nebular, molecular hydrogen and HCN lines superimposed, together with the "Unidentified Infrared" (UIR) features. The nebular lines are consistent with emission by a low density gas. We conclude that the Spitzer data, combined with other information, are incompatible with CK Vul being a classical nova remnant in "hibernation" after the event of 1670, a "Very Late Thermal Pulse", a "Luminous Red Variable" such as V838 Mon, or a "Diffusion-induced nova". The true nature of CK Vul remains a mystery.

  17. Accretion Flow Properties of MAXI J1543-564 During 2011 Outburst from TCAF Solution

    CERN Document Server

    Chatterjee, Debjit; Chakrabarti, Sandip K; Mondal, Santanu; Jana, Arghajit

    2016-01-01

    We derive accretion flow properties of the transient black hole candidate (BHC) MAXI~J1543-564 using the RXTE data. We use Two-Component Advective Flow (TCAF) solution to fit the data of the very initial rising phase of outburst (from 2011 May 10 to 2011 May 15). $2.5-25$~keV spectra are fitted using the TCAF solution {\\it fits} file as a local additive table model in XSPEC. We extract physical flow parameters such as the two component (Keplerian disk and sub-Keplerian halo) accretion rates and size and the property of the Compton cloud (post shock region close to a black hole). Similar to other classical transient BHCs, monotonic evolution of low frequency quasi-periodic oscillations (QPOs) are observed during the rising phase of the outburst, which is fitted with the propagating oscillatory shock (POS) model which describes how the Compton cloud properties change from day to day. From the nature of variations of TCAF model fitted physical flow parameters and QPOs, we only found hard-intermediate and soft-in...

  18. Draconid 2011 outburst observations from Slovenia

    Science.gov (United States)

    Kac, Javor

    2015-06-01

    The 2011 Draconid outburst results are presented based on visual, video and photographic observations. A population index of r = 2.6 ± 0.1 and a maximum zenithal hourly rate of 460 ± 60 on 2011 October 8 at 20h11m UT are obtained from the visual observations. Twelve double-station Draconids form an average geocentric radiant at α = 262°4 ± 0°8, δ = +55°4 ± 0°4, with a velocity v_∞ = 22.4 ± 0.4 km/s. Single-station video observations indicate a radiant at α = 261°4 ± 1°4, δ = +55°8 ± 1°4, and a velocity of v_∞ = 20.6 ± 0.5 km/s. A flux profile is presented based on 358 video Draconids, and a maximum flux of 87 Draconids per 1000 km^{2} per hour is found on 2011 October 8 at 20h15m UT.

  19. Colors of the pulsations and flickering of Sy Cancri during outburst

    International Nuclear Information System (INIS)

    The spectra of the short period (approx.30 s) oscillations and flickering of the dwarf nova Sy Cnc have been determined by simultaneous measuring the optical flux in three broad, contiguous spectral bands during an optical outburst of the star. The spectrum of the oscillation rises too rapidly toward short wavelengths to be consistent with any simple thermal model. The colors of the flickering are even more extreme (i.e., more ultraviolet) than those of the pulsations. No timing differences were detected to a fraction of a second between the ultraviolet (U), cyan (B+V, or C) and red (R, to 9000 A) bands of the pulsations; thus, the optical oscillations appear to arise from a single physical location in the binary system. Without a detailed study of a more complicated class of models, which may include recombination radiation from H I, He I, and He II in addition to a thermal model, it is impossible to assign a temperature to the oscillations and thereby determine whether they are produced directly on the white dwarf or in the accretion disk

  20. The MAXI/GSC Nova-Alert System and results of its first 68 months

    Science.gov (United States)

    Negoro, Hitoshi; Kohama, Mitsuhiro; Serino, Motoko; Saito, Hiroki; Takahashi, Tomonori; Miyoshi, Sho; Ozawa, Hiroshi; Suwa, Fumitoshi; Asada, Masato; Fukushima, Kosuke; Eguchi, Satoshi; Kawai, Nobuyuki; Kennea, Jamie; Mihara, Tatehiro; Morii, Mikio; Nakahira, Satoshi; Ogawa, Yuji; Sugawara, Aya; Tomida, Hiroshi; Ueno, Shiro; Ishikawa, Masaki; Isobe, Naoki; Kawamuro, Taiki; Kimura, Masashi; Masumitsu, Takahiro; Nakagawa, Yujin E.; Nakajima, Motoki; Sakamoto, Takanori; Shidatsu, Megumi; Sugizaki, Mutsumi; Sugimoto, Juri; Suzuki, Kazuhiko; Takagi, Toshihiro; Tanaka, Kazuki; Tsuboi, Yohko; Tsunemi, Hiroshi; Ueda, Yoshihiro; Yamaoka, Kazutaka; Yamauchi, Makoto; Yoshida, Atsumasa; Matsuoka, Masaru

    2016-06-01

    Various transient phenomena on a timescale ranging from seconds to days appear at unexpected sky positions in X-rays. MAXI, Monitor of All-sky X-ray Image, on the International Space Station has been monitoring about 95% of the sky a day and has detected transient objects since 2009 August. Here, we describe quasi-real-time data processing systems of MAXI and a subsequent nova-alert system to find transient objects, and present the capabilities for the nova-alert system to detect transient events with excess fluxes from ≳80 mCrab in a single scan transit to ≳8 mCrab for 4 d, and to send prompt alert information to the world in less than 30 s after the onboard detection of a burst, making the best use of the International Space Station (ISS) real-time network. We also report on highlights of scientific results obtained with the system until the end of the first extended mission phase, 2015 March. Including 15 X-ray novae solely or independently discovered, we have reported on 177 transient phenomena, such as X-ray bursts, outbursts, and state transitions of X-ray binaries and X-ray flares from active stars and blazars, via the Astronomer's Telegram, and on 63 burst phenomena of other types via the Gamma-ray Coordinates Network. We summarize the results of these transient sources and phenomena focusing on the detections with the nova-alert system, and some new transients yet unpublished or requiring attention.

  1. Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables -- VI. Spin rates, propellering, and coherence

    CERN Document Server

    Warner, Brian

    2007-01-01

    We examine published observations of dwarf nova oscillations (DNOs) on the rise and decline of outbursts and show that their rates of change are in reasonable agreement with those predicted from the magnetic accretion model. We find evidence for propellering in the late stages of outburst of several dwarf novae, as shown by reductions in EUVE fluxes and from rapid increases of the DNO periods. Reanalysis of DNOs observed in TY PsA, which had particularly large amplitudes, shows that the apparent loss of coherence during late decline is better described as a regular switching between two nearby periods. It is partly this and the rapid deceleration in some systems that make the DNOs harder to detect. We suggest that the 28.95 s periodicity in WZ Sge, which has long been a puzzle, is caused by heated regions in the disc, just beyond the corotation radius, which are a consequence of magnetic coupling between the primary and gas in the accretion disc. This leads to a possible new interpretation of the `longer peri...

  2. HOPS 383: An Outbursting Class 0 Protostar in Orion

    CERN Document Server

    Safron, Emily J; Megeath, S Thomas; Furlan, Elise; Stutz, Amelia M; Stanke, Thomas; Billot, Nicolas; Rebull, Luisa M; Tobin, John J; Ali, Babar; Allen, Lori E; Booker, Joseph; Watson, Dan M; Wilson, T L

    2015-01-01

    We report the dramatic mid-infrared brightening between 2004 and 2006 of HOPS 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 microns with a brightness increase also apparent at 4.5 microns. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K_s imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L_sun. Post-outburst time-series mid- and far-infrared photometry shows no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a six-year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller tha...

  3. 2014-2015 Multiple Outbursts of 15P/Finlay

    CERN Document Server

    Ishiguro, Masateru; Hanayama, Hidekazu; Kwon, Yuna Grace; Kim, Yoonyoung; Lee, Myung Gyoon; Watanabe, Makoto; Akitaya, Hiroshi; Kawabata, Koji; Itoh, Ryosuke; Nakaoka, Tatsuya; Yoshida, Michitoshi; Imai, Masataka; Sarugaku, Yuki; Yanagisawa, Kenshi; Ohta, Kouji; Kawai, Nobuyuki; Miyaji, Takeshi; Fukushima, Hideo; Honda, Satoshi; Takahashi, Jun; Sato, Mikiya; Vaubaillon, Jeremie J; Watanabe, Jun-ichi

    2016-01-01

    Multiple outbursts of a Jupiter-family comet, 15P/Finlay, occurred from late 2014 to early 2015. We conducted an observation of the comet after the first outburst and subsequently witnessed another outburst on 2015 January 15.6-15.7. The gas, consisting mostly of C2 and CN, and dust particles expanded at speeds of 1,110 +/- 180 m/s and 570 +/- 40 m/s at a heliocentric distance of 1.0 AU. We estimated the maximum ratio of solar radiation pressure with respect to the solar gravity beta_max = 1.6 +/- 0.2, which is consistent with porous dust particles composed of silicates and organics. We found that 10^8-10^9 kg of dust particles (assumed to be 0.3 micron - 1 mm) were ejected through each outburst. Although the total mass is three orders of magnitude smaller than that of the 17P/Holmes event observed in 2007, the kinetic energy per unit mass (104 J/kg) is equivalent to the estimated values of 17P/Holmes and 332P/2010 V1 (Ikeya-Murakami), suggesting that the outbursts were caused by a similar physical mechanism....

  4. Drilling coal seam outbursts where particle size matters

    Energy Technology Data Exchange (ETDEWEB)

    Gray, I. [Sigra Pty Ltd. (Australia)

    2009-10-01

    The paper is distilled from the ACARP report 'Coal mine outburst mechanisms, thresholds and predication techniques' originally written in 2006 and added to from recent direct experience of outburst conditions in Central Asian Mines. In an endeavour to provide a basis of prediction as to whether an outburst will occur it takes the approach of examining the total energy that may be released in an outburst. The sources of energy considered are the strain energy that may be released in failure of the coal and in the release of gas. Two modes of gas release are considered, one from pore space and one from diffusion. In the latter case a new model is developed to describe the potential energy release from diffusing particles. In the Australian context it is considered that the elements of energy release due to gas dominate. The critical factors that contributing to energy release in an outburst are: gas content/gas pressure; diffusion coefficient; sorption isotherm; particle size. The less critical factors are: free pore space; stress; and stiffness. 1 ref., 2 figs.

  5. Classification and Spectral Evolution of Outbursts of Aql X-1

    CERN Document Server

    Güngör, Can; Ekşi, K Yavuz

    2014-01-01

    We present a broad classification of all outbursts detected with the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer (RXTE) and the Monitor of All Sky X-Ray Image (MAXI) of Aql X-1. We identify three types of outbursts; long-high, medium-low, and short-low, based on the duration and maximum flux. We analyse the trends in the "phase-space" of flux-derivative versus flux to demonstrate the differences in the three identified outburst types. We present a spectral analysis of the observations of Aql X-1 performed by the Proportional Counter Array (PCA) onboard RXTE during the 2000 and 2011 outbursts of the long-high class and the 2010 outburst of the medium-low class. We model the source spectrum with a hybrid thermal/non-thermal hot plasma emission model (EQPAIR in XSPEC, Coppi 2000) together with a Gaussian component to model the Fe K_alpha emission line. We construct time histories of the source flux, the optical depth of the corona (tau), the seed photon temperature (kT_bb) and the hard state compact...

  6. HOPS 383: AN OUTBURSTING CLASS 0 PROTOSTAR IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Safron, Emily J.; Megeath, S. Thomas; Booker, Joseph [Ritter Astrophysical Observatory, Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Fischer, William J. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Furlan, Elise; Rebull, Luisa M. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA (United States); Stutz, Amelia M. [Max-Planck-Institut für Astronomie, Heidelberg (Germany); Stanke, Thomas [European Southern Observatory, Garching bei München (Germany); Billot, Nicolas [Instituto de Radio Astronomía Milimétrica, Granada (Spain); Tobin, John J. [Leiden Observatory, Leiden (Netherlands); Ali, Babar [Space Science Institute, Boulder, CO (United States); Allen, Lori E. [National Optical Astronomy Observatory, Tucson, AZ (United States); Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Wilson, T. L., E-mail: wjfischer@gmail.com [Naval Research Laboratory, Washington, DC (United States)

    2015-02-10

    We report the dramatic mid-infrared brightening between 2004 and 2006 of Herschel Orion Protostar Survey (HOPS) 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 μm with a brightness increase also apparent at 4.5 μm. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K{sub s} imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L{sub ⊙}. Post-outburst time-series mid- and far-infrared photometry show no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a 6 year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.

  7. The physics of black hole x ray novae

    Science.gov (United States)

    Wheeler, J. C.; Kim, S.-W.; Moscoso, M. D.; Mineshige, S.

    1994-01-01

    X-ray transients that are established or plausible black hole candidates have been discovered at a rate of about one per year in the galaxy for the last five years. There are now well over a dozen black hole candidates, most being in the category of X-ray novae with low-mass companions. There may be hundreds of such transient systems in the galaxy yet to be discovered. Classic black hole candidates like Cygnus X-1 with massive companions are in the minority, and their census in the galaxy and magellanic clouds is likely to be complete. The black hole X-ray novae (BHXN) do not represent only the most common environment in which to discover black holes. Their time dependence gives a major new probe with which to study the physics of accretion into black holes. The BHXN show both a soft X-ray flux from an optically thick disk and a hard power law tail that is reminiscent of AGN spectra. The result may be new insight into the classical systems like Cyg X-1 and LMC X-1 that show similar power law tails, but also to accretion into supermassive black holes and AGN.

  8. Multiwavelength modeling the SED of very slow novae PU Vul and V723 Cas

    CERN Document Server

    Skopal, Augustin

    2013-01-01

    Evolution in the spectrum of very slow novae PU Vul and V723 Cas during their transition from the optical maximum to the nebular phase is investigated using the method of disentangling the composite UV/optical spectra. Model SEDs suggested that a transient decrease in the WD luminosity, during the decline from the maximum, was caused by a negative beaming effect, when a neutral disk around the WD was formed. When the disk disappeared, the luminosity increased again to values from the beginning of the outburst (in the case of V723 Cas, at/above the Eddington limit). This suggests the presence of a mechanism maintaining a high energy output for a much longer time than it is predicted by the current theories. Similarity of light curves, but enormous difference of the separation between the components of PU Vul and V723 Cas binaries suggest that the mechanism is basically powered by the accretor.

  9. X-Ray Flashes in Recurrent Novae: M31N 2008-12a and the Implications of the Swift Non-detection

    CERN Document Server

    Kato, Mariko; Henze, Martin; Ness, Jan-Uwe; Osborne, Julian P; Page, Kim L; Darnley, Matthew J; Bode, Michael F; Shafter, Allen W; Hernanz, Margarita; Gehrels, Neil; Kennea, Jamie; Hachisu, Izumi

    2016-01-01

    Models of nova outbursts suggest that an X-ray flash should occur just after hydrogen ignition. However, this X-ray flash has never been observationally confirmed. We present four theoretical light curves of the X-ray flash for two very massive white dwarfs (WDs) of 1.380 and 1.385 M_sun and for two recurrence periods of 0.5 and 1 years. The duration of the X-ray flash is shorter for a more massive WD and for a longer recurrence period. The shortest duration of 14 hours (0.6 days) among the four cases is obtained for the 1.385 M_sun WD with one year recurrence period. In general, a nova explosion is relatively weak for a very short recurrence period, which results in a rather slow evolution toward the optical peak. This slow timescale and the predictability of very short recurrence period novae give us a chance to observe X-ray flashes of recurrent novae. In this context, we report the first attempt, using the Swift observatory, to detect an X-ray flash of the recurrent nova M31N 2008-12a (0.5 or 1 year recur...

  10. High-Resolution N-Band Observations of the Nova Rs Ophiuchi: First Science with the Keck Interferometer Nuller

    Science.gov (United States)

    Danchi, William

    2008-01-01

    We report new observations of the nova RS Ophiuchi using the Keck Interferometer Nulling Instrument (KIN), approximately 3.8 days following the most recent outburst that occurred on 2006 February 12. These observations represent the first scientific results from the KIN, which operates in N-band from 8 to 12.5 microns. The nulling technique is the sparse aperture equivalent of the conventional coronagraphic technique used in filled aperture telescopes. By fitting the unique KIN inner and outer spatial regime data, we have obtained an angular size of the mid-infrared continuum of 6.2,4.0, or 5.4 mas for a disk profile, Gaussian profile, and shell profile respectively. The data show evidence of enhanced neutral atomic hydrogen emission and atomic metals including silicon located in the inner spatial regime near the white dwarf relative to the outer regime. There are also nebular emission lines and evidence of hot silicate dust in the outer spatial region, centered at approximately 2.5E14 cm from the WD, that are not found in the inner regime. The nova flash in the outer spatial regime evidently excited these features before the blast wave reached these regions. These identifications support the following interpretation. The dust appears to be present between outbursts and was not created during the outburst event. We further discuss the present results in terms of a unifying model of the system that includes an increase in density in the plane of the orbit of the two stars created by a spiral shock wave caused by the motion of the stars through the cool wind of the red giant star. These data show the power and potential of the nulling technique which has been developed for the detection of Earthlike planets around nearby stars for the Terrestrial Planet Finder Mission and Darwin missions.

  11. High-energy observations of the state transition of the X-ray nova and black hole candidate XTE J1720-318

    DEFF Research Database (Denmark)

    Bel, M.C.; Rodriguez, J.; Sizun, P.;

    2004-01-01

    We report the results of extensive high-energy observations of the X-ray transient and black hole candidate XTE J1720-318 performed with INTEGRAL, XMM-Newton and RXTE. The source, which underwent an X-ray outburst in 2003 January, was observed in February in a spectral state dominated by a soft......, typical of a black-hole binary in the so-called High/Soft State. We then followed the evolution of the source outburst over several months using the INTEGRAL Galactic Centre survey observations. The source became active again at the end of March: it showed a clear transition towards a much harder state...... of the black hole X-ray novae class which populate our galactic bulge and we discuss its properties in the frame of the spectral models used for transient black hole binaries....

  12. Effect of Water Invasion on Outburst Predictive Index of Low Rank Coals in Dalong Mine

    OpenAIRE

    Jiang, Jingyu; Cheng, Yuanping; Mou, Junhui; Jin, Kan; Cui, Jie

    2015-01-01

    To improve the coal permeability and outburst prevention, coal seam water injection and a series of outburst prevention measures were tested in outburst coal mines. These methods have become important technologies used for coal and gas outburst prevention and control by increasing the external moisture of coal or decreasing the stress of coal seam and changing the coal pore structure and gas desorption speed. In addition, techniques have had a significant impact on the gas extraction and outb...

  13. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  14. Outburst flood evolution at Russell Glacier, western Greenland

    DEFF Research Database (Denmark)

    Carrivick, Jonathan; Russell, Andrew; Ingeman-Nielsen, Thomas;

    2013-01-01

    Outburst floods have produced a distinctive and widespread Quaternary record both onshore and offshore via widespread and intense geomorphological impacts, yet these impacts remain poorly understood due to a lack of modern analogues. This study therefore makes the first systematic quantification of...... the evolution of a bedrockchannelled outburst flood. Channel topography was obtained from digitised aerial photographs, a 5m grid resolution DEM and bathymetric surveys. Flood inundation was measured in the field from dGPS measurements. Flood evolution was analysed with application of a numerical...... model. Novel flood metrics, including ‘rate-of-rise-to-peak’ and ‘persistence-above-a-value’ of hydraulics were calculated. The key findings were that outburst floods; (i) that enter intermediary lakes are halted in terms of propagation whilst basin filling proceeds to the outlet level, dissipated of...

  15. On the Hubble Space Telescope Trigonometric Parallax of the Dwarf Nova SS Cygni

    CERN Document Server

    Nelan, Edmund P

    2013-01-01

    SS Cygni is one of the brightest dwarf novae (DNe), and one of the best-studied prototypes of the cataclysmic variables. Astrometric observations with the Fine Guidance Sensors (FGS) on the Hubble Space Telescope (HST), published in 2004, gave an absolute trigonometric parallax of 6.06+/-0.44 mas. However, recent very-long-baseline interferometry (VLBI), obtained during radio outbursts of SS Cyg, has yielded a significantly larger absolute parallax of 8.80+/-0.12 mas, as well as a large difference in the direction of the proper motion compared to the HST result. The VLBI distance reduces the implied luminosity of SS Cyg by about a factor of two, giving good agreement with predictions based on accretion-disk theory in order to explain the observed DN outburst behavior. This discrepancy raises the possibility of significant systematic errors in FGS parallaxes and proper motions. We have reanalyzed the archival HST/FGS data, including (1) a critical redetermination of the parallaxes of the background astrometric...

  16. A FAR ULTRAVIOLET SPECTROSCOPIC EXPLORER SURVEY OF HIGH-DECLINATION DWARF NOVAE

    International Nuclear Information System (INIS)

    We present a spectral analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of eight high-declination dwarf novae (DNs) obtained from a Cycle 7 FUSE survey. These DN systems have not been previously studied in the UV and little is known about their white dwarfs (WDs) or accretion disks. We carry out the spectral analysis of the FUSE data using synthetic spectra generated with the codes TLUSTY and SYNSPEC. For two faint objects (AQ Men and V433 Ara) we can only assess a lower limit for the WD temperature or mass accretion rate. NSV 10934 was caught in a quiescent state and its spectrum is consistent with a low-mass accretion rate disk. For five objects (HP Nor, DT Aps, AM Cas, FO Per, and ES Dra), we obtain WD temperatures between 34,000 K and 40,000 K and/or mass accretion rates consistent with intermediate to outburst states. These temperatures reflect the heating of the WD due to on-going accretion and are similar to the temperatures of other DNs observed on the rise to, and in decline from outburst. The WD temperatures we obtain should therefore be considered as upper limits, and it is likely that during quiescence AM Cas, FO Per, and ES Dra are near the average WD Teff for catalcysmic variables above the period gap (∼30,000 K), similar to U Gem, SS Aur, and RX And.

  17. Common Envelope ejection for a Luminous Red Nova in M101

    CERN Document Server

    Blagorodnova, N; Polshaw, J; Kasliwal, M M; Cao, Y; Cody, A M; Doran, G B; Elias-Rosa, N; Fraser, M; Fremling, C; Gonzalez-Fernandez, C; Harmanen, J; Jencson, J; Kankare, E; Kudritzki, R -P; Kulkarni, S R; Magnier, E; Manulis, I; Masci, F J; Mattila, S; Nugent, P; Ochner, P; Pastorello, A; Reynolds, T; Smith, K; Sollerman, J; Taddia, F; Terreran, G; Tomasella, L; Turatto, M; Vreeswijk, P; Wozniak, P; Zaggia, S

    2016-01-01

    We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red nova in M101 galaxy, spanning 16 years. The lightcurve of the object showed two peaks with absolute magnitudes $M_R\\leq-12.4$ and $M_R=-12$, on 2014 November 11 and 2016 February 17 respectively. The spectral energy distributions during the second maximum show a cool outburst temperature of $\\approx$ 3700 K and low velocity ($\\approx$ 300 km s$^{-1}$) for H I, Ca II, Ba II and K I lines. Archival data, from 15 to 8 years before the outburst, show a progenitor star that is an F-type yellow super-giant with $L$~$\\geq$~8.7~$\\times\\ 10^4$ L$_{\\odot}$ and temperature $\\approx$7000 K. This star has just finished the H burning phase in the core, started expanding, and now is crossing the Hertzsprung gap. We argue that the progenitor is a binary system, with masses $\\rm{M1}\\sim 18$ M$_{\\odot}$and $\\rm{M2}\\sim16.2$ M$_{\\odot}$, with the more evolved system overfilling the Roche lobe....

  18. GSC2.3 N152008120 - a new SU UMa-type dwarf nova in Draco

    CERN Document Server

    Boyd, David; Kato, Taichi; Koff, Robert; Miller, Ian; Oksanen, Arto; Pickard, Roger; Poyner, Gary

    2009-01-01

    We report observations during 2008 October of the first recorded superoutburst of a previously unknown SU UMa-type dwarf nova in Draco located at 19h 14m 43.52s +60d 52m 14.1s (J2000). Simbad lists a 21st magnitude star at this position with identifiers GSC2.3 N152008120 and USNO-B1.0 1508-0249096. The outburst reached magnitude 14.9, its amplitude was approximately 6 magnitudes and its duration at least 11 days. About 11 days after the end of the main outburst there was a short-lived rebrightening by more than 2 magnitudes. Superhumps were observed with a mean period of 0.07117(1) d and amplitude 0.12 mag. There was a distinct shortening in the superhump period around cycle 80 with Psh = 0.07137(2) d before and Psh = 0.07091(2) d after. We saw weak evidence of an increasing Psh before cycle 80 with dPsh/dt = 3.4(2.0) * 10-5.

  19. Isotopic 32S/33S ratio as a diagnostic of presolar grains from novae

    Directory of Open Access Journals (Sweden)

    A. Parikh

    2014-10-01

    Full Text Available Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,γ34Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33S(3He,d34Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole–dipole–dipole–dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10° and 55°. Twenty-four levels in 34Cl over Ex=4.6–5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33S + p threshold, spanning the energy range required for calculations of the thermonuclear 33S(p,γ34Cl rate in classical nova explosions. We have determined a new 33S(p,γ34Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of ≤5 variation in the 33S(p,γ34Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of SCa isotopes by ≤20%. In particular, the predicted 32S/33S ratio is 110–130 for the nova model considered, compared to 110–440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130–200, the 32S/33S ratio may be used to distinguish between grains of nova and supernova origin.

  20. Water outburst activity in Comet 17P/Holmes

    Science.gov (United States)

    de Almeida, Amaury A.; Boice, Daniel C.; Picazzio, Enos; Huebner, Walter F.

    2016-08-01

    Cometary outbursts are sporadic events whose mechanisms are not well known where the activity and consequently the brightness can increase hundreds of thousands of times within a few hours to several days. This indicates a dramatic departure from thermal equilibrium between the comet and interplanetary space and is usually documented by "light curves". In a typical cometary outburst, the brightness can increase by 2-5 magnitudes (Whitney, 1955; Gronkowski and Wesolowski, 2015). In only 42 h, Comet 17P/Holmes was reported to brighten from a magnitude of about 17 to about 2.4 at the height of the burst, representing the largest known outburst by a comet. We present the H2O production rate of Holmes for the megaburst occurring between 23 and 24 October 2007. For this, we selected more than 1900 photometric observations from the International Comet Quarterly Archive of Photometric Data (Green, 2007) and use the Semi-Empirical Method of Visual Magnitudes (SEMVM; de Almeida et al., 2007). We clearly show that the comet achieved an average water production rate of 5 × 1029 molecules s-1, corresponding to a water gas loss rate of 14,960 kg s-1, in very good agreement with Schleicher (2009) who derived the water production rate using OH measurements on 1 Nov 2007 (about 8 days after the outburst). We discuss possible physical processes that might cause cometary outbursts and propose a new qualitative mechanism, the Pressurized Obstructed Pore (POP) model. The key feature of POP is the recrystallization of water in the surface regolith as it cools, plugging pores and blocking the release of subsurface gas flow. As the interior gas pressure increases, an outburst is eventually triggered. POP is consistent with current observations and can be tested in the future with observations (e.g., Rosetta in situ measurements) and detailed simulations.

  1. Nova laser assurance-management system

    International Nuclear Information System (INIS)

    In a well managed project, Quality Assurance is an integral part of the management activities performed on a daily basis. Management assures successful performance within budget and on schedule by using all the good business, scientific, engineering, quality assurance, and safety practices available. Quality assurance and safety practices employed on Nova are put in perspective by integrating them into the overall function of good project management. The Nova assurance management system was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management system. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project

  2. LBT/LUCIFER near-infrared spectroscopy of PV Cephei. An outbursting young stellar object with an asymmetric jet

    Science.gov (United States)

    Caratti o Garatti, A.; Garcia Lopez, R.; Weigelt, G.; Tambovtseva, L. V.; Grinin, V. P.; Wheelwright, H.; Ilee, J. D.

    2013-06-01

    Context. Young stellar objects (YSOs) occasionally experience enhanced accretion events, the nature of which is still poorly understood. The discovery of various embedded outbursting YSOs has recently questioned the classical definition of EXors and FUors. Aims: We present a detailed spectroscopic investigation of the young eruptive star PV Cep, to improve our understanding of its nature and characterise its circumstellar environment after its last outburst in 2004. Methods: The analysis of our medium-resolution spectroscopy in the near-infrared (NIR, 0.9-2.35 μm), collected in 2012 at the Large Binocular Telescope with the IR spectrograph LUCIFER, allows us to infer the main stellar parameters (visual extinction, accretion luminosity, mass accretion and ejection rates), and model the inner disc, jet, and wind. Results: The NIR spectrum displays several strong emission lines associated with accretion/ejection activity and circumstellar environment. Our analysis shows that the brightness of PV Cep is fading, as well as the mass accretion rate (2 × 10-7 M⊙ yr-1 in 2012 vs. ~5 × 10-6 M⊙ yr-1 in 2004), which is more than one order of magnitude lower than in the outburst phase. Among the several emission lines, only the [Fe ii] intensity increased after the outburst. The observed [Fe ii] emission delineates blue- and red-shifted lobes, both with high- and low-velocity components, which trace an asymmetric jet and wind, respectively. The observed emission in the jet has a dynamical age of 7-8 years, indicating that it was produced during the last outburst. The visual extinction decreases moving from the red-shifted (AV(red) = 10.1 ± 0.7 mag) to the blue-shifted lobe (AV(blue) = 6.5 ± 0.4 mag). We measure an average electron temperature of 17 500 K and electron densities of 30 000 cm-3 and 15 000 cm-3 for the blue and the red lobe, respectively. The mass ejection rate in both lobes is ~1.5 × 10-7 M⊙ yr-1, approximately matching the high accretion rate observed

  3. The NOvA Technical Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Ayres, D.S.; Drake, G.R.; Goodman, M.C.; Grudzinski, J.J.; Guarino, V.J.; Talaga, R.L.; Zhao, A.; /Argonne; Stamoulis, P.; Stiliaris, E.; Tzanakos, G.; Zois, M.; /Athens U. /Caltech /UCLA /Fermilab /College de France /Harvard U. /Indiana U. /Lebedev Inst. /Michigan State U. /Minnesota U., Duluth /Minnesota U.

    2007-10-08

    Technical Design Report (TDR) describes the preliminary design of the NOvA accelerator upgrades, NOvA detectors, detector halls and detector sites. Compared to the March 2006 and November 2006 NOvA Conceptual Design Reports (CDR), critical value engineering studies have been completed and the alternatives still active in the CDR have been narrowed to achieve a preliminary technical design ready for a Critical Decision 2 review. Many aspects of NOvA described this TDR are complete to a level far beyond a preliminary design. In particular, the access road to the NOvA Far Detector site in Minnesota has an advanced technical design at a level appropriate for a Critical Decision 3a review. Several components of the accelerator upgrade and new neutrino detectors also have advanced technical designs appropriate for a Critical Decision 3a review. Chapter 1 is an Executive Summary with a short description of the NOvA project. Chapter 2 describes how the Fermilab NuMI beam will provide a narrow band beam of neutrinos for NOvA. Chapter 3 gives an updated overview of the scientific basis for the NOvA experiment, focusing on the primary goal to extend the search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations and measure the sin{sup 2}(2{theta}{sub 13}) parameter. This parameter has not been measured in any previous experiment and NOvA would extend the search by about an order of magnitude beyond the current limit. A secondary goal is to measure the dominant mode oscillation parameters, sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sub 32}{sup 2} to a more precise level than previous experiments. Additional physics goals for NOvA are also discussed. Chapter 4 describes the Scientific Design Criteria which the Fermilab accelerator complex, NOvA detectors and NOvA detector sites must satisfy to meet the physics goals discussed in Chapter 3. Chapter 5 is an overview of the NOvA project. The changes in the design relative to the NOvA CDR are discussed. Chapter 6 summarizes the NOvA

  4. Discovery of a cosmological, relativistic outburst via its rapidly fading optical emission

    Energy Technology Data Exchange (ETDEWEB)

    Cenko, S. Bradley; Nugent, Peter E.; Miller, Adam A.; Bloom, Joshua S.; Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Kulkarni, S. R.; Horesh, Assaf; Carpenter, John; Perley, Daniel A.; Groot, Paul J.; Hallinan, G. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Corsi, Alessandra [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, CA 91125 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Frail, Dale A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Gruber, D.; Rau, Arne [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); Gal-Yam, Avishay; Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); MacLeod, Chelsea L. [Physics Department, United States Naval Academy, 572c Holloway Road, Annapolis, MD 21402 (United States); Kasliwal, Mansi M., E-mail: cenko@astro.berkeley.edu [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (United States); and others

    2013-06-01

    We report the discovery by the Palomar Transient Factory (PTF) of the transient source PTF11agg, which is distinguished by three primary characteristics: (1) bright (R {sub peak} = 18.3 mag), rapidly fading (ΔR = 4 mag in Δt = 2 days) optical transient emission; (2) a faint (R = 26.2 ± 0.2 mag), blue (g' – R = 0.17 ± 0.29 mag) quiescent optical counterpart; and (3) an associated year-long, scintillating radio transient. We argue that these observed properties are inconsistent with any known class of Galactic transients (flare stars, X-ray binaries, dwarf novae), and instead suggest a cosmological origin. The detection of incoherent radio emission at such distances implies a large emitting region, from which we infer the presence of relativistic ejecta. The observed properties are all consistent with the population of long-duration gamma-ray bursts (GRBs), marking the first time such an outburst has been discovered in the distant universe independent of a high-energy trigger. We searched for possible high-energy counterparts to PTF11agg, but found no evidence for associated prompt emission. We therefore consider three possible scenarios to account for a GRB-like afterglow without a high-energy counterpart: an 'untriggered' GRB (lack of satellite coverage), an 'orphan' afterglow (viewing-angle effects), and a 'dirty fireball' (suppressed high-energy emission). The observed optical and radio light curves appear inconsistent with even the most basic predictions for off-axis afterglow models. The simplest explanation, then, is that PTF11agg is a normal, on-axis long-duration GRB for which the associated high-energy emission was simply missed. However, we have calculated the likelihood of such a serendipitous discovery by PTF and find that it is quite small (≈2.6%). While not definitive, we nonetheless speculate that PTF11agg may represent a new, more common (>4 times the on-axis GRB rate at 90% confidence) class of relativistic

  5. Outburst flood evolution at Russell Glacier, western Greenland

    DEFF Research Database (Denmark)

    Carrivick, Jonathan L.; Turner, Andy G.D.; Russell, Andrew J.;

    2013-01-01

    Glacial lake outburst floods have produced a distinctive and widespread Quaternary record both onshore and offshore via widespread and intense geomorphological impacts, yet these impacts remain poorly understood due to a lack of modern analogues. This study therefore makes a systematic quantifica......Glacial lake outburst floods have produced a distinctive and widespread Quaternary record both onshore and offshore via widespread and intense geomorphological impacts, yet these impacts remain poorly understood due to a lack of modern analogues. This study therefore makes a systematic...... quantification of the evolution of a bedrock-channelled outburst flood. Channel topography was obtained from digitised aerial photographs, a 5 m grid resolution DEM and bathymetric surveys. Flood inundation was measured in the field from dGPS measurements. Flood evolution was analysed with application of a...... numerical model. Novel flood metrics, including ‘rate-of-rise-to-peak’ and ‘persistence-above-a-value’ of hydraulics were calculated. The key findings were that outburst floods; (i) that enter intermediary lakes are dramatically attenuated in terms of propagation whilst basin filling proceeds to the outlet...

  6. Outburst from SS 433 observed with BOOTES-2/COLORES

    Science.gov (United States)

    Caballero-Garcia, M. D.; Castro-Tirado, A.; Jelinek, M.; et al.

    2014-08-01

    In light of the recent extreme outburst of SS 433 (ATELs #6347, #6355) and follow-up by SWIFT (ATEL #6364) the 0.6m TELMA robotic telescope at the BOOTES-2 (+COLORES) astronomical station in Malaga (Spain), obtained optical 4000-9000 A spectra starting at 2014-08-01 and ending at 2014-08-07.

  7. Optical behaviour of BL Lacertae during the great 1997 outburst.

    Science.gov (United States)

    Tosti, G.; Luciani, M.; Fiorucci, M.; Massaro, E.; Nesci, R.; Maesano, M.; Montagni, F.; Villata, M.; Raiteri, C. M.; de Francesco, G.; Sobrito, G.; Takalo, L. O.; Sillanpää, A.; Katajainen, S.; Pursimo, T.; Kurtanidze, O. M.; Nikolashvili, M. G.

    The authors report here optical observations of BL Lac performed during its large outburst in 1997. During this monitoring the source reached the brightest magnitude observed in the last 25 years, showing a variability pattern characterized by rapid flares lasting from few hours to days.

  8. Mc Neil's Nebula in Orion: The Outburst History

    CERN Document Server

    Briceño, C; Hernández, J; Calvet, N; Hartmann, L; Megeath, T; Calkins, P BerlindM; Hoyer, S

    2004-01-01

    We present a sequence of I-band images obtained at the Venezuela 1m Schmidt telescope during the outburst of the nebula recently discovered by J.W. McNeil in the Orion L1630 molecular cloud. We derive photometry spanning the pre-outburst state and the brightening itself, a unique record including 14 epochs and spanning a time scale of ~5 years. We constrain the beginning of the outburst at some time between Oct. 28 and Nov. 15, 2003. The light curve of the object at the vertex of the nebula, the likely exciting source of the outburst, reveals that it has brightened ~5 magnitudes in about 4 months. The time scale for the nebula to develop is consistent with the light travel time, indicating that we are observing light from the central source scattered by the ambient cloud into the line of sight. We also show recent FLWO optical spectroscopy of the exciting source and of the nearby HH 22. The spectrum of the source is highly reddened; in contrast, the spectrum of HH 22 shows a shock spectrum superimposed on a c...

  9. A DOUBLE-PEAKED OUTBURST OF A 0535+26 OBSERVED WITH INTEGRAL, RXTE, AND SUZAKU

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, I. [Laboratoire AIM, CEA/IRFU, CNRS/INSU, Universite Paris Diderot, CEA DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Pottschmidt, K.; Marcu, D. M. [Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Barragan, L.; Wilms, J.; Kreykenbohm, I. [Dr. Karl Remeis-Sternwarte and ECAP, FAU Erlangen-Nuremberg, Sternwartstr. 7, D-96049 Bamberg (Germany); Ferrigno, C. [ISDC Data Centre for Astrophysics, University of Geneva, Chemin d' Ecogia 16, CH-1290 Versoix (Switzerland); Klochkov, D.; Suchy, S.; Santangelo, A.; Staubert, R. [Institut fuer Astronomie und Astrophysik, Sand 1, D-72076 Tuebingen (Germany); Zurita Heras, J. A. [Francois Arago Centre, APC (UMR 7164 Universite Paris Diderot, CNRS/IN2P3, CEA/DSM, Observatoire de Paris), 13 rue Watt, F-75205 Paris Cedex 13 (France); Kretschmar, P. [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, Villanueva de la Canada, E-28080 Madrid (Spain); Fuerst, F. [Space Radiation Lab, California Institute of Technology, MC 290-17 Cahill, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Rothschild, R. [Center for Astrophysics and Space Science, UCSD, La Jolla, CA 92093 (United States); Finger, M. H. [National Space Science and Technology Center, 320 Sparkman Drive NW, Huntsville, AL 35805 (United States); Camero-Arranz, A. [Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Fac. de Ciencies, Torre C5, parell, 2a planta, E-08193 Barcelona (Spain); Makishima, K. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Enoto, T. [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Iwakiri, W., E-mail: isabel.caballero@cea.fr [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570 (Japan); and others

    2013-02-20

    The Be/X-ray binary A 0535+26 showed a normal (type I) outburst in 2009 August. It is the fourth in a series of normal outbursts associated with the periastron, but is unusual because it presented a double-peaked light curve. The two peaks reached a flux of {approx}450 mCrab in the 15-50 keV range. We present results of the timing and spectral analysis of INTEGRAL, RXTE, and Suzaku observations of the outburst. The energy-dependent pulse profiles and their evolution during the outburst are studied. No significant differences with respect to other normal outbursts are observed. The centroid energy of the fundamental cyclotron line shows no significant variation during the outburst. A spectral hardening with increasing luminosity is observed. We conclude that the source is accreting in the sub-critical regime. We discuss possible explanations for the double-peaked outburst.

  10. Nova laser alignment control system

    International Nuclear Information System (INIS)

    Alignment of the Nova laser requires control of hundreds of optical components in the ten beam paths. Extensive application of computer technology makes daily alignment practical. The control system is designed in a manner which provides both centralized and local manual operator controls integrated with automatic closed loop alignment. Menudriven operator consoles using high resolution color graphics displays overlaid with transport touch panels allow laser personnel to interact efficiently with the computer system. Automatic alignment is accomplished by using image analysis techniques to determine beam references points from video images acquired along the laser chain. A major goal of the design is to contribute substantially to rapid experimental turnaround and consistent alignment results. This paper describes the computer-based control structure and the software methods developed for aligning this large laser system

  11. Nova Gas's pipeline to Asia

    International Nuclear Information System (INIS)

    The involvement of the Calgary-based company NOVA Gas International (NGI) in Malaysia's peninsular gas utilization (PGU) project, was described. Phase I and II of the project involved linking onshore gas processing plants with a natural gas transmission system. Phase III of the PGU project was a gas transmission pipeline that began midway up the west coast of peninsular Malaysia to the Malaysia-Thailand border. The complex 549 km pipeline included route selection, survey and soil investigation, archaeological study, environmental impact assessment, land acquisition, meter-station construction, telecommunication systems and office buildings. NGI was the prime contractor on the project through a joint venture with OGP Technical Services, jointly owned by NGI and Petronas, the Thai state oil company. Much of NGI's success was attributed to excellent interpersonal skills, particularly NGI's ability to build confidence and credibility with its Thai partners

  12. V2491 Cyg - a possible recurrent nova ?

    CERN Document Server

    Ragan, E; Tomov, T; Swierczynski, E; Brozek, T; Galan, C; Rozanski, P; Wiecek, M; Wychudzki, P

    2010-01-01

    Nova V2491 Cyg was discovered on April 10.72 UT 2008 (Nakano, 2008). Here we present spectrophotometric premises that V2491 Cyg can be a good candidate for recurrent nova (RNe). Its properties are compared to five well known RNe with red dwarf secondaries (U Sco, V394 Cra, T Pyx, CI Aql, IM Nor) and recently confirmed as recurrent nova V2487 Oph (Pagnotta et al.,2008). Photometric $U, B, V, R_C, I_C$ and moderate resolution (R$\\sim 1500$) spectral observations of V2491 Cyg were carried out in the Torun Observatory (Poland) between April 14 and May 20 2008.

  13. Early infrared development of Nova Cygni 1975

    International Nuclear Information System (INIS)

    Broad-band infrared photometry of Nova Cygni is presented for 50 days following discovery. During the first three days, the energy distribution is approximately that of a blackbody. A distance of 1.5 +- 0.5 kpc is derived from a measurement of the blackbody-expansion parallax. After the fourth day, the energy spectrum is close to F/sub v/=constant. A possible mechanism for producing this rapid change is discussed. Although the nova is unusual in several respects, the physical parameters derived from the observations are about normal for a very fast galactic nova

  14. The X-ray emission from Nova V382 Velorum I. The hard component observed with BeppoSAX

    CERN Document Server

    Orio, M; Benjamin, R; Amati, L; Frontera, F; Greiner, J; Ögelman, H B; Mineo, T; Starrfield, S G; Trussoni, E

    2001-01-01

    We present BeppoSAX observations of Nova Velorum 1999 (V382 Vel), done in a broad X-ray band covering 0.1-300 keV only 15 days after the discovery and again after 6 months. The nova was detected at day 15 with the BeppoSAX instruments in the energy range 1.8-10 keV and we attribute the emission to shocks in the ejecta. The plasma temperature was kT~6 keV and the unabsorbed flux was F(x)~4.3 x 10(-11) erg/cm**2/s. The nebular material was affected by high intrinsic absorption of the ejecta. 6 months after after the outburst, the intrinsic absorption did not play a role, the nova had turned into a bright supersoft source, and the hot nebular component previously detected had cooled to a plasma temperature kT<=1 keV. No emission was detected in either observation above 20 keV.

  15. Dengue: uma nova abordagem Dengue: a reappraisal

    Directory of Open Access Journals (Sweden)

    José Carlos Serufo

    2000-10-01

    Full Text Available Os conceitos de dengue clássico, com ou sem hemorragia, e de febre hemorrágica do dengue (FHD que, pode cursar sem fenômenos hemorrágicos, com ou sem síndrome do choque do dengue (SCD, são revistos neste artigo. As definições clássicas propostas, úteis em outros tempos, geram confusão e dificultam a tomada de decisões no momento do tratamento dos pacientes com as formas graves da doença porque deixaram de incorporar novos conceitos e avanços terapêuticos. A classificação do dengue proposta neste trabalho, e apresentada em fluxograma, incorpora os conceitos atuais de sepse, síndrome da resposta inflamatória sistêmica (SIRS e síndrome da angústia respiratória do adulto (SARA. A nova classificação serve de guia para orientar a conduta terapêutica inicial e aproxima o tratamento do dengue aos protocolos e rotinas já implantados nos diversos centros hospitalares de urgência, facilitando a atuação dos serviços de saúde em situações de surtos epidêmicos.Previous definition of classic dengue, with or without bleeding, and of dengue hemorrhagic fever (DHF that may evolve without bleeding and with or without dengue shock syndrome (DSS are reviewed here. The classical approach to the diagnosis and treatment of dengue, although useful in the past, nowadays breeds confusion and adds a burden to the physician's task of decision-making regarding the treatment of patients with severe forms of the disease. The classification of dengue proposed in this paper, and summarized in a diagram, incorporates new concepts about sepsis, systemic inflammatory response syndrome (SIRS, and acute respiratory distress syndrome (ARDS. This new approach, in our view, is a useful guide to initial evaluation and treatment of the disease. It also approximates the dengue syndrome to other protocols and medical procedures routinely used in intensive care units, making it easier to be followed by the health personnel working in areas subject to

  16. Old novae and the SW Sex phenomenon

    CERN Document Server

    Schmidtobreick, Linda

    2013-01-01

    From a large observing campaign, we found that nearly all non- or weakly magnetic cataclysmic variables (CVs) in the orbital period range between 2.8 and 4 hours are of SW Sex type and as such experience very high mass transfer rates. The exceptions seem to be some old novae that have periods around 3.5 h. Their spectra do not show the typical SW Sex characteristics but rather resemble those of dwarf novae with low mass transfer rates. The presence of old novae in this period range of SW Sex stars that do not follow the trend but show instead rather low mass transfer rates is interpreted as evidence for an effect of the nova eruption on the mass transfer rate of the underlying CV similar to the hibernation scenario.

  17. Pulse shaping on the Nova laser system

    International Nuclear Information System (INIS)

    Inertial confinement fusion requires temporally shaped pulses to achieve high gain efficiency. Recently, we demonstrated the ability to produce complex temporal pulse shapes at high power at 0.35 microns on the Nova laser system. 2 refs., 2 figs

  18. Nova Eruptions with Infrared Interferometric Observations

    CERN Document Server

    Ribeiro, Valério A R M

    2015-01-01

    Infrared interferometric observations have a great deal of potential to unravel the nature of the nova eruptions. We suggest that techniques, already in place, to derive the ejection details at optical wavelengths be used with infrared interferometric observations to derive parameters such as the ejected mass in a nova eruption. This is achievable based on modelling the initial phase of the eruption when the infrared light is dominated by the free-free thermal process.

  19. Quark Nova Model for Fast Radio Bursts

    OpenAIRE

    Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid

    2015-01-01

    FRBs are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the sur...

  20. NOVA Corporation of Alberta annual report, 1992

    International Nuclear Information System (INIS)

    Nova Corporation and its related businesses are involved in natural gas production, gas pipelines, consulting services, and upgrading of natural gas into chemicals and plastics. Nova owns Alberta Gas Transmission Division, the primary gas transportation system in Alberta, with 11,400 miles of pipeline and total deliveries in 1992 of 3.4 trillion ft3. Nova also owns 50% of Foothills Pipe Lines Ltd., one of Canada's largest carriers of exported gas, and 50% of TQM Pipeline Partnership, which transports natural gas in Quebec. Nova conducts its chemicals business through Novacor Chemicals Ltd., which has plants in Alberta, Ontario, Quebec, and the USA. Novacor's major petrochemicals are methanol, ethylene, propylene, and styrene and its major plastics are polystyrene, polypropylene, and polyethylene. Nova's gas-producing branch Novalta Resources produced 26 billion ft3 of natural gas in 1992 and has proven reserves of 334 billion ft3. Nova's net income in 1992 was $164 million, compared to only $46 million in 1991. The company's operations, along with management discussion and analysis, are presented for 1992 and financial statements are included. 20 figs., 43 tabs

  1. Pulsed power supply for Nova Upgrade

    International Nuclear Information System (INIS)

    This report describes work carried out at the Center for Electromechanics at The University of Texas at Austin (CEM-UT). A baseline design of the Nova Upgrade has been completed by Lawrence Livermore National Laboratory. The Nova Upgrade is an 18 beamline Nd: glass laser design utilizing fully relayed 4x4 30 cm aperture segmented optical components. The laser thus consists of 288 independent beamlets nominally producing 1.5 to 2.0 MJ of 0.35 μm light in a 3 to 5 ns pulse. The laser design is extremely flexible and will allow a wide range of pulses to irradiate ICF targets. This facility will demonstrate ignition/gain and the scientific feasibility of ICF for energy and defense applications. The pulsed power requirements for the Nova Upgrade are given. CEM-UT was contracted to study and develop a design for a homopolar generator/inductor (HPG/inductor) opening switch system which would satisfy the pulsed power supply requirements of the Nova Upgrade. The Nd:glass laser amplifiers used in the Nova Upgrade will be powered by light from xenon flashlamps. The pulsed power supply for the Nova Upgrade powers the xenon flashlamps. This design and study was for a power supply to drive flashlamps

  2. Effects of FU Orionis Outbursts on Protoplanetary Disks

    Science.gov (United States)

    Bodenheimer, Peter

    1997-01-01

    In the early stages of work under this grant, we developed simulations to match the light curves of the three best studied systems: FU Ori, V1515 Cyg, & V1057 Cyg (Bell et al. 1995). We compared the details of model results to observations to test the validity of the thermal ionization instability model for outburst. In this paper, we were able to answer several of the key objections to the accretion disk outburst model for the FU Orionis phenomenon (eg. Herbig 1989). The declines in line width and reddening observed in V1057 Cyg following peak light had been used as arguments against the disk instability model. We showed these effects to be natural consequences of the slow outward progression and limited radial excursion of the ionization front during outburst. By the end of the grant period, we had begun combining the inner and outer disk models to derive the radiation expected in the planet forming region of the disk. A crucial step in this was the development of a radiative transfer model of the complete inner and outer disk system (Turner, Bodenheimer, & Bell 1997). In this work, wavelength dependent opacities were used to synthesize images and spectral energy distributions of FU Ori objects. New detailed opacities provided by Alexander (1995) allowed the resolution of coarse features such as silicate emission lines. Data for the fits were taken from the time dependent simulations in Bell et al. (1995) to which was added the effect of disk to disk or "self"-reprocessing which accounts for the illumination of the outer disk by the inner disk (Bell 1998). Through the course of work on this grant we have made considerable progress in computing detailed models of both the active outburst region of the disk and the outer quiescent disk. We have begun an investigation into the effects of a cocooning envelope. Direct comparisons with observations lend confidence that the basic underlying assumptions of the outburst model are reasonable. We are now ready to build upon

  3. What classicality? Decoherence and Bohr's classical concepts

    CERN Document Server

    Schlosshauer, Maximilian

    2010-01-01

    Niels Bohr famously insisted on the indispensability of what he termed "classical concepts." In the context of the decoherence program, on the other hand, it has become fashionable to talk about the "dynamical emergence of classicality" from the quantum formalism alone. Does this mean that decoherence challenges Bohr's dictum and signifies a break with the Copenhagen interpretation-for example, that classical concepts do not need to be assumed but can be derived? In this paper we'll try to shine some light down the murky waters where formalism and philosophy cohabitate. To begin, we'll clarify the notion of classicality in the decoherence description. We'll then discuss Bohr's and Heisenberg's take on the quantum-classical problem and reflect on different meanings of the terms "classicality" and "classical concepts" in the writings of Bohr and his followers. This analysis will allow us to put forward some tentative suggestions for how we may better understand the relation between decoherence-induced classical...

  4. Nova Sagittarii 2009 Number 3

    Science.gov (United States)

    Waagen, Elizabeth O.

    2009-08-01

    V5583 Sgr (Nova Sgr 2009 No. 3) was independently discovered by Koichi Nishiyama, Kurume, Fukuoka-ken, Japan, and Fujio Kabashima, Miyaki-cho, Saga-ken, Japan, at unfiltered CCD magnitude 7.7 on August 6.494 UT, and by Grzegorz Pojmanski, Dorota Szczygiel, and Bogumil Pilecki, Warsaw University Astronomical Observatory, observed by ASAS3 at 7.78V on Aug. 6.182 UT. Coordinates from Nishiyama and Kabashima are 18:07:07.67 -33:46:33.9 (2000.0), from Pojmanski et al. 18:07:08 -33:46.6 (2000.0). It was confirmed optically by Nishiyama and Kabashima on Aug. 6.494 UT, and by Leonid Elenin, Moscow, and spectroscopically by Mitsugu Fujii, Fujii Bisei Observatory, Okayama, Japan, on Aug. 7.60 UT, and by Akira Arai et al. on Aug. 7.63 UT. V5583 Sgr (name assigned August 17 by the GCVS team, Moscow, after this Alert Notice was issued) has been assigned the name VSX J180707.6-334633 with the AUID 000-BJP-536. Observations should be reported to the AAVSO International Database as V5583! Sgr, N Sgr 2009 No. 3, N Sgr 2009#3, or VSX J180707.6-334633.

  5. A strategy for rock/coal outburst prevention

    Institute of Scientific and Technical Information of China (English)

    D.H. Steve Zou; CHENG Jiu-long

    2007-01-01

    The current practice of rock/coal outburst monitoring, prevention and control was reviewed. The uncertainty of major factors contributing to the occurrence of such hazards and the complexicity of mining conditions surrounding the occurrence were analyzed. A strategic concept for rock/coal outburst prevention was introduced. The objective is to identify the bursting potential in an area, rather than predicting the bursting, by introducing a multi- dimension index model: potential-of-bursting (POB), taking into consideration major contributing factors. In application, once the index has passed certain critical level indicating high risk, actions must be taken to reduce the bursting potential and to effectively prevent the hazard from occurring. A conceptual 2D model involving stress and methane pressure was described to demonstrate the methodology for determining the POB. However in practice, a POB model has to be established through experiments, field monitoring and calibration against case studies. To achieve this objective, coordinated research and international collaboration will be needed.

  6. A extração de cafeína em bebidas estimulantes: uma nova abordagem para um experimento clássico em química orgânica Caffeine extraction from stimulating beverages: a new approach for a classic organic chemistry experiment

    Directory of Open Access Journals (Sweden)

    Eugênia Cristina Souza Brenelli

    2003-01-01

    Full Text Available Caffeine extraction procedures from water soluble and water insoluble materials for preparing stimulating beverages are described. Water soluble materials used were instant tea and coffee and water insoluble materials were, among others, guaraná powder and maté leaves. The extraction of caffeine from water soluble materials, especially instant tea, is more suitable for an organic chemistry teaching laboratory than the classic experiment using tea leaves, due to the economy of time and a larger amount of extracted caffeine. The procedure is time-saving and requires only a four-hour period. The experiments illustrate the extraction process as used in undergraduate organic chemistry laboratories.

  7. Exquisite Nova Light Curves from the Solar Mass Ejection Imager (SMEI)

    CERN Document Server

    Hounsell, R; Hick, P P; Buffington, A; Jackson, B V; Clover, J M; Shafter, A W; Darnley, M J; Mawson, N R; Steele, I A; Evans, A; Eyres, S P S; O'Brien, T J

    2010-01-01

    We present light curves of three classical novae (KT Eridani, V598 Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) derived from data obtained by the Solar Mass Ejection Imager (SMEI) on board the Coriolis satellite. SMEI provides near complete sky-map coverage with precision visible-light photometry at 102-minute cadence. The light curves derived from these sky maps offer unprecedented temporal resolution around, and especially before, maximum light, a phase of the nova eruption normally not covered by ground-based observations. They allow us to explore fundamental parameters of individual objects including the epoch of the initial explosion, the reality and duration of any pre-maximum halt (found in all three fast novae in our sample), the presence of secondary maxima, speed of decline of the initial light curve, plus precise timing of the onset of dust formation (in V1280 Sco) leading to estimation of the bolometric luminosity, white dwarf mass and object distance. For KT Eri, Liverpool Telescop...

  8. Preventing Coal and Gas Outburst Using Methane Hydration

    Institute of Scientific and Technical Information of China (English)

    吴强; 何学秋

    2003-01-01

    According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in the coal seams to form hydrate. The paper analyzes the feasibility of forming the methane hydrate in the coal seam from the several sides, such as, temperature,pressure, and gas components, and the primary trial results indicate the problems should be settled before the industrialization appliance realized.

  9. Microseism Monitoring System for Coal and Gas Outburst

    OpenAIRE

    Li Zhenbi; Zhao Baiting

    2012-01-01

    The outburst forecast of coal and gas is a complex system engineering. On the basis of the analysis of microseism monitoring principle, a simplex positioning algorithm for microseism monitoring is designed; a mine microseism monitoring system is established to canalize mine microseism. Mechanism of the error producing and noise reduction measures is studied. We can analyze the data of the microseism monitoring to find coal or rock vibration caused by mining activities. Microseism monitoring s...

  10. The experience of aggressive outbursts in intermittent explosive disorder

    OpenAIRE

    Kulper, Daniel A.; Kleiman, Evan M.; McCloskey, Michael S.; Berman, Mitchell E.; Coccaro, Emil F.

    2014-01-01

    Conceptualizations of Intermittent Explosive Disorder (IED) have suffered from a scarcity of research investigating the subjective experience and phenomenology of the aggressive outbursts among those with IED relative to those who partake in more normative forms of aggression. Furthermore, though some studies have shown that individuals with IED are more impaired and have a poorer quality of life, few studies looked at negative outcomes specific to an individual with IED’s aggressive behavior...

  11. GBM Observations of Be X-Ray Binary Outbursts

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Finger, M. H.; Jenke, P. A.

    2014-01-01

    Since 2008 we have been monitoring accreting pulsars using the Gamma ray Burst Monitor (GBM) on Fermi. This monitoring program includes daily blind full sky searches for previously unknown or previously quiescent pulsars and source specific analysis to track the frequency evolution of all detected pulsars. To date we have detected outbursts from 23 transient accreting pulsars, including 21 confirmed or likely Be/X-ray binaries. I will describe our techniques and highlight results for selected pulsars.

  12. EVN detection of Aql X-1 in outburst

    Science.gov (United States)

    Tudose, V.; Paragi, Z.; Miller-Jones, J.; Garrett, M.; Fender, R.; Rushton, A.; Spencer, R.

    2009-11-01

    The X-ray binary Aql X-1 has been in outburst in the last few weeks (ATEL #2288, #2296, #2299, #2302, #2303). We observed the system on 2009 November 19 between 14:30-19:00 UT at 5 GHz with the European VLBI Network (EVN) using the e-VLBI technique. The participating radio telescopes were Effelsberg (1 Gbps), Medicina (896 Mbps), Onsala 25m (1 Gbps), Torun (1 Gbps), Westerbork (1 Gbps), Yebes (896 Mbps), and Cambridge (128 Mbps).

  13. Atmospheric deposition 2000. NOVA 2003; Atmosfaerisk deposition 2000. NOVA 2003

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Hertel, O.; Hovmand, M.F.; Kemp, K.; Skjoeth, C.A.

    2001-11-01

    This report presents measurements and calculations from the atmospheric part of NOVA 2003 and covers results for 2000. It summarises the main results concerning concentrations and depositions of nitrogen, phosphorus and sulphur compounds related to eutrophication and acidification. Depositions of atmospheric compounds to Danish marine waters as well as land surface are presented. Measurements: In 2000 the monitoring program consisted of eight stations where wet deposition of ammonium, nitrate, phosphate (semi quantitatively) and sulphate were measured using bulk precipitation samplers. Six of the stations had in addition measurements of atmospheric content of A, nitrogen, phosphorus, and sulphur compounds in gas and particulate phase carried out by use of filter pack samplers. Filters were analysed at the National Environmental Research Institute. Furthermore nitrogen dioxide were measured using nitrogen dioxide filter samplers and monitors. Model calculations: The measurements in the monitoring program were supplemented with model calculations of concentrations and depositions of nitrogen and sulphur compounds to Danish land surface, marine waters, fjords and bays using the ACDEP model (Atmospheric Chemistry and Deposition). The model is a so-called trajectory model and simulates the physical and chemical processes in the atmosphere using meteorological and emission data as input. The advantage of combining measurements with model calculations is that the strengths of both methods is obtained. Conclusions concerning: 1) actual concentration levels at the monitoring stations, 2) deposition at the monitoring stations, 3) seasonal variations and 4) long term trends in concentrations and depositions are mainly based on the direct measurements. These are furthermore used to validate the results of the model calculations. Calculations and conclusions concerning: 1) depositions to land surface and to the individual marine water, 2) contributions from different emission

  14. Distribution of Heavy Hydrocarbon in Coal Seams and Its Use in Predicting Outburst of Coal

    Institute of Scientific and Technical Information of China (English)

    蒋承林; 李增华; 韩颖

    2003-01-01

    In order to verify whether any special gas component exists in outburst samples or not, coal samples from both outburst coal seams and non-outburst coal seams were collected. Some gases were extracted from the samples and analyzed qualitatively and quantitatively on chromatogram-mass spectrograph. The qualitative analysis show that there is no special gases in coal seams. And the quantitative analysis indicates that the heavy hydrocarbon content in coal samples from outburst coal seams is apparently higher than that from non-outburst district ones, which reflects the damage of geological tectonic movement to coal body in history. Therefore, the heavy hydrocarbon content of coal sample can be used as an index to predict coal outburst.

  15. The estimation of a possibility of outburst origin in long mine workings

    International Nuclear Information System (INIS)

    The article presents results from the possibility of creation of outbursts of coal and gas based on the calculation of the active forces, which try to create a heavy and passive forces, which prevent outbursts. Analysis of torrential Mine Paskov Staric plant shows that critical indicators to evaluate the potential susceptibility of coal and gas outbursts reported only a small number resulting from coal and gas outbursts an increased risk characterizing the second level of danger and requiring certain preventive measures. The aim of this paper is to point to other factors contributing to the potential of coal and gas outbursts (eg. strength of coal, the parameters of the work, its cross section, the circuit and daily practice, variability of seam thickness, the influence of tectonic perturbation) as well as using a mathematical model to suggest the possibility of its use in the evaluation of susceptibility of coal seams to outbursts of coal and gas. (authors)

  16. Outbursts of EX Hydrae mass-transfer events or disc instabilities?

    CERN Document Server

    Hellier, C; Naylor, T; Bateson, F M; Jones, A; Overbeek, D; Stubbings, R; Mukai, K; Hellier, Coel; Kemp, Jonathan; Bateson, Frank M.; Jones, Albert; Overbeek, Danie; Stubbings, Rod; Mukai, Koji

    2000-01-01

    We present the 45-yr record of EX Hya's lightcurve and discuss the characteristics of its 15 observed outbursts. We then concentrate on the 1998 outburst, reporting the first outburst X-ray observations. We discover an X-ray beat-cycle modulation, indicating that an enhanced accretion stream couples directly with the magnetosphere in outburst, confirming our previous prediction. Optical eclipse profiles late in outburst show that the visible light is dominated by an enhanced mass-transfer stream overflowing the accretion disc. We are uncertain whether the enhanced mass transfer is triggered by a disc instability, or by some other cause. While in outburst, EX Hya shows some of the characteristics of SW Sex stars.

  17. Differential radon measurements for outburst prediction in coal mines

    International Nuclear Information System (INIS)

    In some areas, coal mines are subject to occasional outbursts consisting mainly of carbon dioxide or methane and coal dust. These vary widely in severity, but can cause loss of life. There are several techniques which may permit prediction of the outbursts. These include monitoring acoustic signals or continuous measurement of methane, carbon dioxide or radon concentrations. While it is not expected that any one will be adequate on its own, each technique is being studied so that a combination of all can be evaluated. This paper presents an experiment in which the concentration of radon in underground air is measured with high precision upon entry to and leaving a work face. This was considered the most practicable way to detect any radon flux anomalies preceding an outburst in a working mine. There are many practical difficulties in mounting an experiment in an active mine because of the dusty, wet conditions and because of the need for rigorous safety requirements in an environment which may contain an explosive mixture of air and methane. Details of the development of suitable equipment are given, and an analysis made of the first two months of operation. (author)

  18. Glacier lake outburst floods of the Guangxieco Lake in 1988 in Tibet, China

    OpenAIRE

    J. J. Liu; Z. L. Cheng; Y. Li

    2013-01-01

    Glacial lake outburst floods (GLOFs) have become more frequent and attracted more and more attention under conditions of global warming. However, there are few observations of the reasons for outbursts and their processes because of their unexpected occurrence and their inaccessible location in high-elevation areas. The GLOF of the Guangxieco Lake, which is the only outburst lake below an elevation of 4000 m in Tibet, provides a case study for discussing the...

  19. The 1988 glacial lake outburst flood in Guangxieco Lake, Tibet, China

    OpenAIRE

    Liu, J.-J.; Cheng, Z.-L.; Li, Y.

    2014-01-01

    The 1988 glacial lake outburst flood (GLOF) in Guangxieco Lake is studied based on geomorphological evidence, interviews with local residents, field surveys in 1990 and 2007, and satellite images from different years. The findings are as follows. (1) The outburst event was caused by two major factors, namely, intense pre-precipitation and persistent high temperatures before the outburst and the low self-stability of the terminal moraine dam as a result of perennial piping. (...

  20. First Science with the Keck Interferometer Nuller High Spatial Resolution N-Band Observations of the Recurrent Nova RS Ophiuchi

    Science.gov (United States)

    Barry, Richard K.; Danchi, W. C.; Traub, W.; Kuchner, M.; Wisniewski, J. P.; Akeson, R.; Colavita, M.; Greenhouse, M, A.; Koresko, C.; Serabyn, E.; Sokoloski, J. L.

    2008-01-01

    We report observations of the nova RS 0phiuchi using the Keck Interferometer Nuller (KIN) taken approximately 3.8 days following the most recent outburst that occurred on 2006 February 12. The KIN operates in N-band from approx. 8 to 12.5 microns in a nulling mode - the sparse aperture equivalent of the conventional coronagraphic technique used in filled aperture te1escopes. In this mode the stellar light is suppressed by a destructive fringe, effectively enhancing the contrast of the circumstellar material located near the star. In a second, constructive-fringe mode, the instrument detects primarily the light from the central, bright source. These are the outer and inner spatial regimes, resprectively. We will describe the capabilities of the KIN, including these unique modes, and outline how they were key in our discovery that dust does not appear to be created in the outburst as in previous models, but instead was created between nova events. We also show how these first results from the KIN are consistent with Spitzer data. The KIN data show evidence of enhanced neutral atomic hydrogen emission and atomic metals including silicon located in the inner spatial regime near the white dwarf (WD) relative to the outer regime. There are also nebular emission lines and evidence of hot silicate dust in the outer spatial region, centered at approximately 17 AU from the WD, that are not found in the inner regime. The KIN and Spitzer data suggest that these emissions were excited by the nova flash in the outer spatial regime before the blast wave reached these regions. We describe the present results in terms of a new model for dust creation in recurrent novae that includes an increase in density in the plane of the orbit of the two stars created by a spiral shock wave caused by the motion of the stars through the cool wind of the red giant star. These data show the power and potential of the nulling technique which has been developed for the detection of Earth

  1. Nova Discovery Efficiency 1890-2014; Only 43%±6% of the Brightest Nova Are Discovered

    Science.gov (United States)

    Schaefer, Bradley E.

    2014-06-01

    Galactic nova discovery has always been the domain of the best amateur astronomers, with the only substantial exception being the use of the Harvard plates from 1890-1947. (Modern CCD surveys have not produced any significant nova discoveries.) From 1890-1946, novae were discovered by gentlemen who deeply knew the stars in the sky and who checked for new stars on every clear night. This all changed when war surplus binoculars became commonly available, so the various organizations (e.g., AAVSO, BAA) instructed their hunters to use binoculars to regularly search small areas of the Milky Way. In the 1970s the hunters largely switched to blinking photographs, while they switched to CCD images in the 1990s, all exclusively in Milky Way regions. Currently, most hunters use 'go-to' scopes to look deeply only in the Milky Way, use weekly or monthly cadences, never go outside to look up at the light-polluted skies, and do not have the stars memorized at all. This situation is good for catching many faint novae, but is inefficient for catching the more isotropic and systematically-fast bright novae.I have made an exhaustive analysis of all known novae to isolate the effects on the relative discovery efficiency as a function of decade, the elongation from the Sun, the Moon's phase, the declination, the peak magnitude, and the duration of the peak. For example, the relative efficiency for novae south of declination -33° is 0.5 before 1953, 0.2 from 1953-1990, and 0.8 after 1990. My analysis gives the overall discovery efficiency to be 43%±6%, 30%, 22%, 12%, and 6% for novae peaking brighter than 2, 4, 6, 8, and 10 mag. Thus, the majority of first magnitude novae are being missed. The bright novae are lost because they are too close to the Sun, in the far south, and/or very fast. This is illustrated by the discovery rate for Vpeak<2 novae being once every five years before 1946, yet only one such nova (V1500 Cyg) has been seen in the last 68 years. A critical consequence of

  2. Geotechnical risk management to prevent coal outburst in room-and-pillar mining

    Institute of Scientific and Technical Information of China (English)

    Zhang Peter⇑; Peterson Scott; Neilans Dan; Wade Scott; McGrady Ryan; Pugh Joe

    2016-01-01

    A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the influence zones created by remnant pillars and gob-solid boundaries. Though coal outburst is gener-ally associated with heavy loading of coal pillars, its occurrence is difficult to predict. Risk management provides a proactive tool to minimize coal outburst in room-and-pillar mining under deep cover. Risk assessment is the first step in identifying and quantifying outburst risk factors. The primary risk factors for coal outburst are overburden depth, roof and floor strength, geological anomalies, mining type, multi-seam mining, and panel width. A risk assessment chart can be used to proactively screen out min-ing sections with high risk of coal outburst for further analysis. Gob-solid boundaries and remnant pillars are critical factors in evaluation of the coal outburst risk of multi-seam mining. Risk identification, risk assessment, geologic influence mapping, geotechnical evaluation, risk analysis, risk mitigation, and mon-itoring are essential elements of coal outburst risk management process. Training is an integral part of risk management for risk identification and communication between all the stakeholders including man-agement, technical and safety personnel, and miners.

  3. Study on the formation mechanism of shock wave in process of coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    SUN Dong-ling; MIAO Fa-tian; LIANG Yun-pei

    2009-01-01

    According to the research results of motion parameters of coal-gas flow, ana-lyzed the formation mechanism of shock waves at different states of coal-gas flow in the process of coal and gas outburst, and briefly described the two possible cases of outburst shock wave formation and their formation conditions in the process of coal and gas out-burst, and then pointed out that a high degree of under-expanded coal-gas flow was the main reason for the formation of a highly destructive shock wave. The research results improved the shock wave theory in coal and gas outburst.

  4. Accretion outbursts in self-gravitating protoplanetary disks

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jaehan; Hartmann, Lee [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Zhu, Zhaohuan [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Nelson, Richard P., E-mail: jaehbae@umich.edu, E-mail: lhartm@umich.edu, E-mail: zhuzh@astro.princeton.edu, E-mail: r.p.nelson@qmul.ac.uk [Astronomy Unit, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2014-11-01

    We improve on our previous treatments of the long-term evolution of protostellar disks by explicitly solving disk self-gravity in two dimensions. The current model is an extension of the one-dimensional layered accretion disk model of Bae et al. We find that gravitational instability (GI)-induced spiral density waves heat disks via compressional heating (i.e., PdV work), and can trigger accretion outbursts by activating the magnetorotational instability (MRI) in the magnetically inert disk dead zone. The GI-induced spiral waves propagate well inside of the gravitationally unstable region before they trigger outbursts at R ≲ 1 AU where GI cannot be sustained. This long-range propagation of waves cannot be reproduced with the previously used local α treatments for GI. In our standard model where zero dead-zone residual viscosity (α{sub rd}) is assumed, the GI-induced stress measured at the onset of outbursts is locally as large as 0.01 in terms of the generic α parameter. However, as suggested in our previous one-dimensional calculations, we confirm that the presence of a small but finite α{sub rd} triggers thermally driven bursts of accretion instead of the GI + MRI-driven outbursts that are observed when α{sub rd} = 0. The inclusion of non-zero residual viscosity in the dead zone decreases the importance of GI soon after mass feeding from the envelope cloud ceases. During the infall phase while the central protostar is still embedded, our models stay in a 'quiescent' accretion phase with M-dot {sub acc}∼10{sup −8}--10{sup −7} M{sub ⊙} yr{sup −1} over 60% of the time and spend less than 15% of the infall phase in accretion outbursts. While our models indicate that episodic mass accretion during protostellar evolution can qualitatively help explain the low accretion luminosities seen in most low-mass protostars, detailed tests of the mechanism will require model calculations for a range of protostellar masses with some constraint on the

  5. Accretion outbursts in self-gravitating protoplanetary disks

    International Nuclear Information System (INIS)

    We improve on our previous treatments of the long-term evolution of protostellar disks by explicitly solving disk self-gravity in two dimensions. The current model is an extension of the one-dimensional layered accretion disk model of Bae et al. We find that gravitational instability (GI)-induced spiral density waves heat disks via compressional heating (i.e., PdV work), and can trigger accretion outbursts by activating the magnetorotational instability (MRI) in the magnetically inert disk dead zone. The GI-induced spiral waves propagate well inside of the gravitationally unstable region before they trigger outbursts at R ≲ 1 AU where GI cannot be sustained. This long-range propagation of waves cannot be reproduced with the previously used local α treatments for GI. In our standard model where zero dead-zone residual viscosity (αrd) is assumed, the GI-induced stress measured at the onset of outbursts is locally as large as 0.01 in terms of the generic α parameter. However, as suggested in our previous one-dimensional calculations, we confirm that the presence of a small but finite αrd triggers thermally driven bursts of accretion instead of the GI + MRI-driven outbursts that are observed when αrd = 0. The inclusion of non-zero residual viscosity in the dead zone decreases the importance of GI soon after mass feeding from the envelope cloud ceases. During the infall phase while the central protostar is still embedded, our models stay in a 'quiescent' accretion phase with M-dot acc∼10−8--10−7 M⊙ yr−1 over 60% of the time and spend less than 15% of the infall phase in accretion outbursts. While our models indicate that episodic mass accretion during protostellar evolution can qualitatively help explain the low accretion luminosities seen in most low-mass protostars, detailed tests of the mechanism will require model calculations for a range of protostellar masses with some constraint on the initial core angular momentum, which affects the

  6. Gamma-ray novae as probes of relativistic particle acceleration at non-relativistic shocks

    CERN Document Server

    Metzger, Brian D; Vurm, Indrek; Hascoet, Romain; Beloborodov, Andrei M; Chomiuk, Laura

    2015-01-01

    The Fermi LAT discovery that classical novae produce >100 MeV gamma-rays establishes that shocks and relativistic particle acceleration are key features of these events. These shocks are likely to be radiative due to the high densities of the nova ejecta at early times coincident with the gamma-ray emission. Thermal X-rays radiated behind the shock are absorbed by neutral gas and reprocessed into optical emission, similar to Type IIn (interacting) supernovae. The ratio of gamma-ray and optical luminosities, L_gam/L_opt, thus sets a lower limit on the fraction of the shock power used to accelerate relativistic particles, e_nth. The measured values of L_gam/L_opt for two classical novae, V1324 Sco and V339 Del, constrains e_nth > 1e-2 and > 1e-3, respectively. Inverse Compton models for the gamma-ray emission are disfavored given the low electron acceleration efficiency, e_nth ~ 1e-4-1e-3, inferred from observations of Galactic cosmic rays and particle-in-cell (PIC) numerical simulations. Recent hybrid PIC simu...

  7. Enquête de satisfaction Novae

    CERN Multimedia

    2014-01-01

    Novae lance une enquête de satisfaction auprès de ses clients. Vous pouvez accéder au questionnaire au sujet des trois restaurants d’entreprise du CERN en utilisant le lien et les codes ci-dessous. Le délai de réponse est fixé au jeudi 29 mai.   https://survey.mis-trend.ch/NOVAE Voici les codes à introduire (en respectant la casse) pour entrer dans le questionnaire, selon le site : CERN Restaurant n°1 : CERN114 CERN Restaurant n°2 : CERN214 CERN Restaurant n°3 : CERN314   Nous attirons votre attention sur le fait que tout questionnaire rempli sera validé. Nous vous prions donc de ne pas utiliser ce lien pour tester le questionnaire. Merci d’avance pour votre collaboration. L'équipe Novae

  8. The Distances of the Galactic Novae

    CERN Document Server

    Özdönmez, Aykut; Cabrera-Lavers, Antonio; Ak, Tansel

    2016-01-01

    Utilising the unique location of red clump giants on colour-magnitude diagrams obtained from various near-IR surveys, we derived specific reddening-distance relations towards 119 Galactic novae for which independent reddening measurements are available. Using the derived distance-extinction relation and the independent measurements of reddening we calculated the most likely distances for each system. We present the details of our distance measurement technique and the results of this analysis, which yielded the distances of 73 Galactic novae and allowed us to set lower limits on the distances of 46 systems. We also present the data of reddening-distance relations derived for each nova, which may be useful to analyze the different Galactic components present in the line of sight.

  9. Uranium in Nova Scotia: a background summary for the uranium inquiry, Nova Scotia

    International Nuclear Information System (INIS)

    Since the mid 1970's Nova Scotia has experienced increased exploration for a number of commodities including uranium. The exploration activity for uranium has resulted in discovery of significant occurrences of the element. It became obvious to the Government of Nova Scotia that a segment of the population of the Province is concerned about the potential hazards associated with the exploration, mining and milling stages of the uranium industry. Public concern has resulted in the appointment of a Commissioner under the Public Inquiries Act of Nova Scotia to inquire and make recommendations to the Governor-in-Council on all aspects of exploration, development, mining, processing, storage, waste management and transportation of uranium in any form. The regulation of mineral exploration and mining activities is carried out by the Nova Scotia Department of Mines and Energy through the Mineral Resources Act of the Province of Nova Scotia. The regulation of the special radioactive aspects involved in the mining and processing of uranium ore is the responsibility of the federal Atomic Energy Control Board. The purposes of this report is to: outline the history of uranium exploration in Nova Scotia; summarize the results of geological surveys by provincial and federal government agencies, universities and exploration companies which document the natural levels of radioactivity in the Province; briefly outline the physical and chemical characteristics of uranium and thorium which make these elements unique and a potential environmental and health concern; outline chronologically the steps taken by the Nova Scotia Department of Mines and Energy to monitor and regulate uranium exploration activities; classify the types of uranium deposits known to occur in Nova Scotia and describe their main geological features; outline the role of the Nova Scotia Department of Mines and Energy in the regulation of mining activities in the Province. The report is written for the interested

  10. X-ray Eclipse Diagnosis of the Evolving Mass Loss in the Recurrent Nova U Scorpii 2010

    CERN Document Server

    Takei, D; Tsujimoto, M; Ness, J -U; Osborne, J P; Starrfield, S; Kitamoto, S

    2013-01-01

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27+/-5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering optical opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric explosion model, we constrain the mass-loss rate as a function of time. For a ratio of actual...

  11. X-RAY ECLIPSE DIAGNOSIS OF THE EVOLVING MASS LOSS IN THE RECURRENT NOVA U SCORPII 2010

    Energy Technology Data Exchange (ETDEWEB)

    Takei, D.; Drake, J. J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Tsujimoto, M. [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Ness, J.-U. [European Space Agency, XMM-Newton Observatory SOC, SRE-OAX, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Osborne, J. P. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Starrfield, S. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Kitamoto, S., E-mail: dtakei@head.cfa.harvard.edu [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan)

    2013-05-20

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27% {+-} 5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10%-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric model, we constrain the mass-loss rate as a function of time. For a ratio of actual to Thomson opacity of 10-100 in supersoft X-rays, we find an ejecta mass of about 10{sup -7}-10{sup -6} M{sub Sun }.

  12. X-RAY ECLIPSE DIAGNOSIS OF THE EVOLVING MASS LOSS IN THE RECURRENT NOVA U SCORPII 2010

    International Nuclear Information System (INIS)

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27% ± 5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10%-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric model, we constrain the mass-loss rate as a function of time. For a ratio of actual to Thomson opacity of 10-100 in supersoft X-rays, we find an ejecta mass of about 10–7-10–6 M☉.

  13. Assurance management program for the 30 Nova laser fusion project

    International Nuclear Information System (INIS)

    The Nova assurance management program was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management program. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project

  14. Planets orbiting Quark Nova compact remnants

    OpenAIRE

    Keränen, P.; Ouyed, R.

    2003-01-01

    We explore planet formation in the Quark Nova scenario. If a millisecond pulsar explodes as a Quark Nova, a protoplanetary disk can be formed out of the metal rich fall-back material. The propeller mechanism transfers angular momentum from the born quark star to the disk that will go through viscous evolution with later plausible grain condensation and planet formation. As a result, earth-size planets on circular orbits may form within short radii from the central quark star. The planets in t...

  15. Terra Nova breaks new ground for alliances

    International Nuclear Information System (INIS)

    This paper reviews the development of alliances to help develop the Terra Nova oil and gas field in the offshore Atlantic areas of Canada. Largely attributed to BP, the strategic alliance concept got its start in the North Sea and on the North Slope of Alaska. BP saw it as the best way to take advantage of economy-of-scale, mitigate risk, and achieve outsourcing goals while retaining their core competencies. This paper reviews the methods of developing the alliances, the developing of a development plan for the Terra Nova field, and how the alliance plans to maximize the profittability of the operation for all involved

  16. Uma nova forma de Coffea

    Directory of Open Access Journals (Sweden)

    C. A. Krug

    1950-01-01

    Full Text Available Nos extensos trabalhos de melhoramento do cafeeiro, há 18 anos em realização na Subdivisão de Genética do Instituto Agronômico, tem-se dedicado especial atenção à espécie C. arabica L., pelo fato de todos os nossos cafèzais pertencerem a esta espécie que, sem dúvida, fornece o produto de melhor qualidade. Nas regiões de terras extremamente cansadas, um dos principais fatôres levados em consideração no melhoramento é a rusticidade, caráter êsse, entretanto, encontrado de preferência em outras espécies, tais como o C. canephora e C. Dewevrei, cujos cafés são de má qualidade. A hibridação interespecífica, que poderia reunir em uma só planta caraterísticos de rusticidade e boa qualidade de bebida, tem o inconveniente de dar origem a plantas triplóides, que são estéreis. Daí se deduz que a obtenção artificial de formas que combinassem êsses caraterísticos constitui problema, cuja solução é extremamente demorada. No presente trabalho, apresentam-se os caracteres de uma nova forma de Coffea, encontrada em cafèzal da Fazenda Itaporã, em Terra Roxa, município de Viradouro, que, com algumas ressalvas, oferece a desejada combinação de caracteres. Trata-se, provàvelmente, de um híbrido espontâneo entre C. arabica e C. Dewevrei, com 2n = 44 cromosômios, extremamente rústico e produtivo, cujas sementes fornecem uma bebida que pode ser classificada como boa. Apenas apresenta, como principal defeito, uma auto-esterilidade quase completa. Os seus caraterísticos botânicos são descritos em detalhe. Devido ao seu porte elevado, ramos abundantes e folhas grandes e coriáceas, esse cafeeiro se assemelha ao C. Dewevrei. Os frutos são oval-elípticos, de um vermelho bem escuro quando maduros, e as sementes oblongas, constatan-do-se elevada percentagem do tipo "moca" e "chocha". Quanto à constituição citológica, as pesquisas conduziram à hipótese de este cafeeiro possuir 22 cromosômios de C. arabica e 22 (n

  17. Nova variedade de Menta arvensis

    Directory of Open Access Journals (Sweden)

    Abelardo Rodrigues Lima

    1952-09-01

    Full Text Available No quarto ano dos trabalhos de seleção com a menta japonêsa, foi encontrado um "seedling", o M. A. 701, que se destacou pela resistência à ferrugem e pela sua rusticidade. Os caracteres botânicos dessa variedade comercial, principalmente hábito vegetativo, coloração das fôlhas e das hastes, a tornam completa' mente distinta da variedade original. Esta distinção se confirma e acentua quando se compara a natureza dos componentes do óleo essencial da menta "Campinas" M. A. 701, descrita no presente trabalho, com a menta japonêsa comum. A maior produtividade da nova variedade comparada com a da menta japonesa comum foi desde logo também constatada pelos primeiros lavradores, a quem foram enviadas pequenas quantidades de rizomas, para plantio experimental. Foram cultivados em 1949-50 cêrca de 12 hectares; cm 1950-51, cêrca de 900 ha, e o prognóstico é que essa variedade tende a substituir totalmente a menta japonêsa anteriormente cultivada em São Paulo, devido ao seu maior valor econômico.A seedling, designated M.A.701, remarkable for its vigor and resistance to rust, was discovered during the fourth year of selection of Japanese mint (Mentha arvensis L. subsp. haplocalix Briquet var. piperascens Holmes or forma piperascens Malinvaud. The botanical characters of the variety derived from this seedling, especially the vegetative habit and colouring of leaves and stems, make it quite different from the original variety. This difference is enhanced, when we compare the nature of the essential oil components of "Campinas" M.A.701, as described in the present paper, with that of the common Japanese mint. The higher yield of the new variety, compared with that of the common Japanese mint, was soon confirmed by the first cultivators, to whom small quantities of rhizomes were sent for experimental planting. About 12 hectars were cultivated em 1949/50 and about 900 hectars in 1950/51. It is expected that the new variety will, on account

  18. Imaging the water snow-line during a protostellar outburst.

    Science.gov (United States)

    Cieza, Lucas A; Casassus, Simon; Tobin, John; Bos, Steven P; Williams, Jonathan P; Perez, Sebastian; Zhu, Zhaohuan; Caceres, Claudio; Canovas, Hector; Dunham, Michael M; Hales, Antonio; Prieto, Jose L; Principe, David A; Schreiber, Matthias R; Ruiz-Rodriguez, Dary; Zurlo, Alice

    2016-07-14

    A snow-line is the region of a protoplanetary disk at which a major volatile, such as water or carbon monoxide, reaches its condensation temperature. Snow-lines play a crucial role in disk evolution by promoting the rapid growth of ice-covered grains. Signatures of the carbon monoxide snow-line (at temperatures of around 20 kelvin) have recently been imaged in the disks surrounding the pre-main-sequence stars TW Hydra and HD163296 (refs 3, 10), at distances of about 30 astronomical units (au) from the star. But the water snow-line of a protoplanetary disk (at temperatures of more than 100 kelvin) has not hitherto been seen, as it generally lies very close to the star (less than 5 au away for solar-type stars). Water-ice is important because it regulates the efficiency of dust and planetesimal coagulation, and the formation of comets, ice giants and the cores of gas giants. Here we report images at 0.03-arcsec resolution (12 au) of the protoplanetary disk around V883 Ori, a protostar of 1.3 solar masses that is undergoing an outburst in luminosity arising from a temporary increase in the accretion rate. We find an intensity break corresponding to an abrupt change in the optical depth at about 42 au, where the elevated disk temperature approaches the condensation point of water, from which we conclude that the outburst has moved the water snow-line. The spectral behaviour across the snow-line confirms recent model predictions: dust fragmentation and the inhibition of grain growth at higher temperatures results in soaring grain number densities and optical depths. As most planetary systems are expected to experience outbursts caused by accretion during their formation, our results imply that highly dynamical water snow-lines must be considered when developing models of disk evolution and planet formation. PMID:27411631

  19. Spacecraft Risk Posed by the 2016 Perseid Outburst

    Science.gov (United States)

    Cooke, W. J.; Moser, D. E.; Moorhead, A. V.

    2016-01-01

    The Perseids are one of the more prolific annual showers, known for high rates and for producing bright meteors. Outbursts of this shower have been noted in the 1860s, the early 1990s, 2004, and 2009, with the 1993 outburst being especially active (peak ZHR above 300). The 1993 Perseids also affected the space-faring nations, as the launch of the STS-51 mission was delayed by NASA until after the shower maximum due to an inability to predict the shower intensity, and the ESA telecommunications satellite Olympus suffered a mission-ending anomaly attributed to a static discharge caused by a Perseid impact [1]. Rates were again high (peak ZHR around 200) in 2009, when the NASA/USGS imaging satellite Landsat-5 experienced a gyro anomaly just before the shower peak; however in this case, the satellite was recovered and normal operations resumed one week later [2]. It is interesting to note that both spacecraft anomalies were not what is typically expected from meteoroid strikes, i.e., physical damage or an attitude displacement due to transfer of momentum. It would appear that the very fast Perseids (59 km s(sup -1) have a marked ability to produce plasma upon impact, which can then serve as a conductive path for discharge currents. The shower is expected to outburst again in 2016, and we present the results from the MSFC Meteoroid Stream Model [4], which predicts enhanced activity on a level similar to that of 2009 as the Earth passes through several debris trails on the night of August 11-12 (UT). We then compare our results to those of other modelers.

  20. Magnetar Outbursts from Avalanches of Hall Waves and Crustal Failures

    CERN Document Server

    Li, Xinyu; Belovorodov, Andrei M

    2016-01-01

    We explore the interaction between Hall waves and mechanical failures inside a magnetar crust, using detailed one-dimentional models that consider temperature-sensitive plastic flow, heat transport and cooling by neutrino emission, as well as the coupling of the crustal motion to the magnetosphere. We find that the dynamics is enriched and accelerated by the fast, short-wavelength Hall waves that are emitted by each failure. The waves propagate and cause failures elsewhere, triggering avalanches. We argue that these avalanches are the likely sources of outbursts in transient magnetars.

  1. e-VLBI observations of SS 433 in outburst

    Science.gov (United States)

    Tudose, V.; Paragi, Z.; Trushkin, S.; Soleri, P.; Fender, R.; Garrett, M.; Spencer, R.; Rushton, A.; Burgess, P.; Kunert-Bajraszewska, M.; Pazderski, E.; Borkowski, K.; Hammargren, R.; Lindqvist, M.; Maccaferri, G.

    2008-11-01

    We have observed the X-ray binary SS 433 on November 6, 2008 between 13:48-18:35 UT at 5 GHz with the European VLBI Network (EVN) using the e-VLBI technique. The radio telescopes participating in the experiment were: Medicina, Onsala 25m, Torun, Jodrell Bank MkII and Cambridge. The X-ray binary SS 433 is in outburst. Trushkin & Nizhelskij (ATel #1819) reported a major flare already active during the RATAN-600 observations in the 1-22 GHz band on 2008 October 28.

  2. A photometric study of DWARF novae

    International Nuclear Information System (INIS)

    A catalogue of UBVRI photoelectric photometry of dwarf novae available in the literature is presented. A comparison with theoretical colour-colour diagrams from steady state discs is made. A correlation of V magnitude with the depth of the Balmer discontinuity is discussed. (author)

  3. ULF fluctuations at Terra Nova Bay (Antarctica

    Directory of Open Access Journals (Sweden)

    A. Meloni

    2000-06-01

    Full Text Available ULF geomagnetic field measurements in Antarctica are a very important tool for better understanding the dynamics of the Earth’s magnetosphere and its response to the variable solar wind conditions. We review the results obtained in the last few years at the Italian observatory at Terra Nova Bay

  4. Enriched Students Program: Nova Scotia, Canada.

    Science.gov (United States)

    Aylward, Margaret

    1987-01-01

    The Russell C. Gordon Elementary School (Nova Scotia, Canada) offers the Enriched Students Program (ESP) for academically gifted students. ESP goals include: fostering and developing individual interests of students; initiating higher level thinking skills; strengthening task commitment; stimulating creativity; promoting leadership qualities; and…

  5. Privatisation and deregulation : the Nova Scotia story

    International Nuclear Information System (INIS)

    This paper described the approach that Nova Scotia Power has taken regarding deregulation. The utility, which was privatised in 1992, operates in competitive markets for more than half of their business, in areas such as home heating, water heating and energy supply for industrial and commercial customers. Since privatization, the utility has seen significant improvements in all major operations of their business. Nova Scotia Power places much focus on their customers to ensure that their service and energy needs are met. The utility has established a call centre to allow customers to reach them 24-hours a day for information during power outages. In 2001, their geographic information system was enhanced to pinpoint locations and causes of outages and to reduce response time. In addition, a Smart Energy Information Service was launched to large commercial and industrial customers. This service combines advanced meters with web-enabled software to help customers manage their energy costs. The utility also places much focus on safety and the environment by examining viable Green Power options such as wind, biomass and hydro-electric generation. Since privatization, the utility has improved reliability, reducing the number of outages by 50 per cent, and the rates have remained less than half the rate of inflation. Nova Scotia Power has also been working with their regulator, the Nova Scotia Utilities and Review Board, to provide new pricing options which would give customers more choices and lower energy costs

  6. Nova pulse power system description and status

    International Nuclear Information System (INIS)

    The Nova laser system is designed to produce critical data in the nation's inertial confinement fusion effort. It is the world's largest peak power laser and presents various unique pulse power problems. In this paper, pulse power systems for this laser are described, the evolutionary points from prior systems are pointed out, and the current status of the hardware is given

  7. Swift/BAT hard X-ray monitoring: A New Outburst of Black Hole Transient H1743-322

    Science.gov (United States)

    Lin, Jie; Yu, Wenfei; Yan, Zhen; Zhang, Hui; Zhang, Wenda

    2016-02-01

    H 1743-322 is one of the a few black hole transients which undergo frequent outbursts in the past decade. From December 2009 to June 2015, it has turned into outbursts for at least eight times (ATEL #2364, #2774, #3277, #3842, #4418, #5241, #6474, and #7607), and its outbursts take place rather regularly with recurrence time of about 7-8 months.

  8. Temper Outbursts in Paediatric Obsessive-Compulsive Disorder and Their Association with Depressed Mood and Treatment Outcome

    Science.gov (United States)

    Krebs, Georgina; Bolhuis, Koen; Heyman, Isobel; Mataix-Cols, David; Turner, Cynthia; Stringaris, Argyris

    2013-01-01

    Background: Temper outbursts in youth with obsessive-compulsive disorder (OCD) are a common source of concern, but remain poorly understood. This study examined a set of hypotheses related to: (a) the prevalence of temper outbursts in paediatric OCD, (b) the associations of temper outbursts with OCD severity and depressive symptoms; and (c) the…

  9. Bidirectional coherent classical communication

    OpenAIRE

    Harrow, Aram W.; Leung, Debbie W.

    2005-01-01

    A unitary interaction coupling two parties enables quantum or classical communication in both the forward and backward directions. Each communication capacity can be thought of as a tradeoff between the achievable rates of specific types of forward and backward communication. Our first result shows that for any bipartite unitary gate, bidirectional coherent classical communication is no more difficult than bidirectional classical communication — they have the same achievable rate regions. ...

  10. Entanglement in Classical Optics

    OpenAIRE

    Ghose, Partha; Mukherjee, Anirban

    2013-01-01

    The emerging field of entanglement or nonseparability in classical optics is reviewed, and its similarities with and differences from quantum entanglement clearly pointed out through a recapitulation of Hilbert spaces in general, the special restrictions on Hilbert spaces imposed in quantum mechanics and the role of Hilbert spaces in classical polarization optics. The production of Bell-like states in classical polarization optics is discussed, and new theorems are proved to discriminate betw...

  11. An April 1991 outburst from 4U0115+63 observed by BATSE

    Energy Technology Data Exchange (ETDEWEB)

    Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Roberts, M. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy; Finger, M.H. [National Aeronautics and Space Administration, Huntsville, AL (United States). George C. Marshall Space Flight Center

    1993-12-01

    4U0115+63 is a recurrent transient X-ray pulsar in a moderately eccentric orbit with a Be star companion, V635 Cas. Many outbursts from this system have been reported over the past twenty years; yet despite the apparent relation between optical outbursts from the companion star and subsequent X-ray transient events, the physical mechanism for the mass transfer in the system remains unclear. In this paper, the authors present the preliminary results of analysis of observations made using BATSE during the 1991 April outburst from this system. This outburst does not fit the pattern of three year recurrence intervals previously suggested by Whitlock, Roussel-Dupre and Priedhorsky (1989). The orbital elements of the system have been updated and do not support the claim of Tamura et al., (1992) that apsidal motion was detected in this system based on the 1990 Ginga outburst.

  12. NOVA Making Stuff Season 2

    Energy Technology Data Exchange (ETDEWEB)

    Leombruni, Lisa; Paulsen, Christine Andrews

    2014-12-12

    Over the course of four weeks in fall 2013, 11.7 million Americans tuned in to PBS to follow host David Pogue as he led them in search of engineering and scientific breakthroughs poised to change our world. Levitating trains, quantum computers, robotic bees, and bomb-detecting plants—these were just a few of the cutting-edge innovations brought into the living rooms of families across the country in NOVA’s four-part series, Making Stuff: Faster, Wilder, Colder, and Safer. Each of the four one-hour programs gave viewers a behind-the-scenes look at novel technologies poised to change our world—showing them how basic research and scientific discovery can hold the keys to transforming how we live. Making Stuff Season 2 (MS2) combined true entertainment with educational value, creating a popular and engaging series that brought accessible science into the homes of millions. NOVA’s goal to engage the public with such technological innovation and basic research extended beyond the broadcast series, including a variety of online, educational, and promotional activities: original online science reporting, web-only short-form videos, a new online quiz-game, social media engagement and promotion, an educational outreach “toolkit” for science educators to create their own “makerspaces,” an online community of practice, a series of nationwide Innovation Cafés, educator professional development, a suite of teacher resources, an “Idealab,” participation in national conferences, and specialized station relation and marketing. A summative evaluation of the MS2 project indicates that overall, these activities helped make a significant impact on the viewers, users, and participants that NOVA reached. The final evaluation conducted by Concord Evaluation Group (CEG) confidently concluded that the broadcast, website, and outreach activities were successful at achieving the project’s intended impacts. CEG reported that the MS2 series and website content were

  13. Classical, Semi-classical and Quantum Noise

    CERN Document Server

    Poor, H; Scully, Marlan

    2012-01-01

    David Middleton was a towering figure of 20th Century engineering and science and one of the founders of statistical communication theory. During the second World War, the young David Middleton, working with Van Fleck, devised the notion of the matched filter, which is the most basic method used for detecting signals in noise. Over the intervening six decades, the contributions of Middleton have become classics. This collection of essays by leading scientists, engineers and colleagues of David are in his honor and reflect the wide  influence that he has had on many fields. Also included is the introduction by Middleton to his forthcoming book, which gives a wonderful view of the field of communication, its history and his own views on the field that he developed over the past 60 years. Focusing on classical noise modeling and applications, Classical, Semi-Classical and Quantum Noise includes coverage of statistical communication theory, non-stationary noise, molecular footprints, noise suppression, Quantum e...

  14. Teleportation via classical entanglement

    CERN Document Server

    Rafsanjani, Seyed Mohammad Hashemi; Magaña-Loaiza, Omar S; Boyd, Robert W

    2015-01-01

    We present a classical counterpart to quantum teleportation that uses classical entanglement instead of quantum entanglement. In our implementation we take advantage of classical entanglement among three parties: orbital angular momentum (OAM), polarization, and the radial degrees of freedom of a beam of light. We demonstrate the teleportation of arbitrary OAM states, in the subspace spanned by any two OAM states, to the polarization of the same beam. Our letter presents the first classical demonstration of a commonly-perceived--quantum phenomenon that requires entanglement among more than two parties.

  15. The NOvA software testing framework

    Science.gov (United States)

    Tamsett, M.; C Group

    2015-12-01

    The NOvA experiment at Fermilab is a long-baseline neutrino experiment designed to study vε appearance in a vμ beam. NOvA has already produced more than one million Monte Carlo and detector generated files amounting to more than 1 PB in size. This data is divided between a number of parallel streams such as far and near detector beam spills, cosmic ray backgrounds, a number of data-driven triggers and over 20 different Monte Carlo configurations. Each of these data streams must be processed through the appropriate steps of the rapidly evolving, multi-tiered, interdependent NOvA software framework. In total there are greater than 12 individual software tiers, each of which performs a different function and can be configured differently depending on the input stream. In order to regularly test and validate that all of these software stages are working correctly NOvA has designed a powerful, modular testing framework that enables detailed validation and benchmarking to be performed in a fast, efficient and accessible way with minimal expert knowledge. The core of this system is a novel series of python modules which wrap, monitor and handle the underlying C++ software framework and then report the results to a slick front-end web-based interface. This interface utilises modern, cross-platform, visualisation libraries to render the test results in a meaningful way. They are fast and flexible, allowing for the easy addition of new tests and datasets. In total upwards of 14 individual streams are regularly tested amounting to over 70 individual software processes, producing over 25 GB of output files. The rigour enforced through this flexible testing framework enables NOvA to rapidly verify configurations, results and software and thus ensure that data is available for physics analysis in a timely and robust manner.

  16. NOVA laser facility for inertial confinement fusion

    International Nuclear Information System (INIS)

    The NOVA laser fusion research facility, currently under construction at Lawrence Livermore National Laboratory, will provide researchers with powerful new tools for the study of nuclear weapons physics and inertial confinement fusion. The NOVA laser system consists of ten large (74 cm diameter) beams, focused and aligned precisely so that their combined energy is brought to bear for a small fraction of a second on a tiny target containing thermonuclear fuel (deuterium and tritium). The ultimate goal of the LLNL inertial confinement fusion program is to produce fusion microexplosions that release several hundred times the energy that the laser delivers to the target. Such an achievement would make inertial confinement fusion attractive for military and civilian applications. The NOVA laser consists of ten beams, capable of concentrating 100 to 150 kJ of energy (in 3 ns) and 100 to 150 TW of power (in 100 ps) on experimental targets by 1985. NOVA will also be capable of frequency converting the fundamental laser wavelength (1.05 μm) to its second (0.525 μm) or third (0.35 μm) harmonic. This additional capability (80 to 120 kJ at 0.525 μm, 40 to 70 kJ at 0.35 μm) was approved by the U.S. Department of Energy (DOE) in April 1982. These shorter wavelengths are much more favorable for ICF target physics. Current construction status of the NOVA facility, intended for completion in the autumn of 1984, will be presented

  17. Nova Scotia wind integration study : final report

    International Nuclear Information System (INIS)

    An independent study was commissioned by the Nova Scotia Department of Energy to identify and assess the impacts of integrating large scale wind power generation into Nova Scotia's electric power system. The purpose of the study was to help Nova Scotia's efforts towards building its renewable energy supply, in order to secure a local energy resource and to protect the environment. This report provided an overview of Nova Scotia's electric power sector, including organizations involved; existing generation system; existing transmission system; renewable energy standards; Nova Scotia Power integrated resource plan; and 2007 renewable energy request for proposals. The major assumptions for the study that were discussed included system parameters; system capacity reserve requirements; expansion plans to 2020; and allocation of new wind generation by zone. Wind resource data and system dispatch modeling were also presented and transmission system modeling was outlined. This included a discussion of steady state reliability requirements; inputs to the load flow model; load flow study and contingency analysis; intra-province transmission congestion; and potential impacts on system security. The report also presented an approach to impact analysis and mitigation such as the impact on greenhouse gas and other air emissions and the impact of wind energy prices on system costs. It was concluded that one of the most important factors in evaluation of the economic impact of wind power integration is the forecasted fuel prices for the thermal units. If the fuel prices had varied significantly from the forecasted values, the study economic impact results could have been quite different. 55 tabs., 64 figs., 1 appendix

  18. The hybrid, coronal lines nova V5588 Sgr (2011 N.2) and its six repeating secondary maxima

    CERN Document Server

    Munari, U; Banerjee, D P K; Ashok, N M; Righetti, G L; Dallaporta, S; Cetrulo, G

    2014-01-01

    The outburst of Nova Sgr 2011 N.2 (=V5588 Sgr) was followed with optical and near-IR photometric and spectroscopic observations for 3.5 years, beginning shortly before the maximum. V5588 Sgr is located close to Galactic center, suffering from E(B-V)=1.56 (+/-0.1) extinction. The primary maximum was reached at V=12.37 on UT 2011 April 2.5 (+/-0.2), and the underlying smooth decline was moderately fast with t(2,V)=38 and t(3,V)=77 days. On top of an otherwise normal decline, six self-similar, fast evolving and bright secondary maxima (SdM) appeared in succession. Only very few other novae have presented so clear secondary maxima. Both the primary maximum and all SdM occurred at later times with increasing wavelengths, by amounts in agreement with expectations from fireball expansions. The radiative energy released during SdM declined following an exponential pattern, while the breadth of individual SdM and the time interval between them widened. Emission lines remained sharp (FWHM~1000 km/s) throughout the whol...

  19. Milliarcsecond N-Band Observations of the Nova RS Ophiuchi: First Science with the Keck Interferometer Nuller

    CERN Document Server

    Barry, R K; Traub, W A; Sokoloski, J L; Wisniewski, J P; Serabyn, E; Kuchner, M J; Akeson, R; Appleby, E; Bell, J; Booth, A; Brandenburg, H; Colavita, M; Crawford, S; Creech-Eakman, M; Dahl, W; Felizardo, C; García, J; Gathright, J; Greenhouse, M A; Herstein, J; Hovland, E; Hrynevych, M; Koresko, C; Ligon, R; Mennesson, B; Millan-Gabet, R; Morrison, D; Palmer, D; Panteleeva, T; Ragland, S; Shao, M; Smythe, R; Summers, K; Swain, M; Tsubota, K; Tyau, C; Vasisht, G; Wetherell, E; Wizinowich, P; Woillez, J

    2008-01-01

    We report observations of the nova RS Ophiuchi (RS Oph) using the Keck Interferometer Nuller (KIN), approximately 3.8 days following the most recent outburst that occurred on 2006 February 12. These observations represent the first scientific results from the KIN, which operates in N-band from 8 to 12.5 microns in a nulling mode. By fitting the unique KIN data, we have obtained an angular size of the mid-infrared continuum of 6.2, 4.0, or 5.4 mas for a disk profile, gaussian profile (FWHM), and shell profile respectively. The data show evidence of enhanced neutral atomic hydrogen emission and atomic metals including silicon located in the inner spatial regime near the white dwarf (WD) relative to the outer regime. There are also nebular emission lines and evidence of hot silicate dust in the outer spatial region, centered at ! 17 AU from the WD, that are not found in the inner regime. Our evidence suggests that these features have been excited by the nova flash in the outer spatial regime before the blast wav...

  20. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II: The Second Year (2009-2010)

    CERN Document Server

    Kato, Taichi; Uemura, Makoto; Henden, Arne; de Miguel, Enrique; Miller, Ian; Dubovsky, Pavol A; Kudzej, Igor; Kiyota, Seiichiro; Hambsch, Franz-Josef; Tanabe, Kenji; Imamura, Kazuyoshi; Kunitomi, Nanae; Takagi, Ryosuke; Nose, Mikiha; Akazawa, Hidehiko; Masi, Gianluca; Nakagawa, Shinichi; Iino, Eriko; Noguchi, Ryo; Matsumoto, Katsura; Fujii, Daichi; Kobayashi, Hiroshi; Ogura, Kazuyuki; Ohtomo, Sachi; Yamashita, Kousei; Yanagisawa, Hirofumi; Itoh, Hiroshi; Bolt, Greg; Monard, Berto; Ohshima, Tomohito; Shears, Jeremy; Ruiz, Javier; Imada, Akira; Oksanen, Arto; Nelson, Peter; Gomez, Tomas L; Staels, Bart; Boyd, David; Voloshina, Irina B; Krajci, Thomas; Crawford, Tim; Stockdale, Chris; Richmond, Michael; Morelle, Etienne; Novak, Rudolf; Nogami, Daisaku; Ishioka, Ryoko; Brady, Steve; Simonsen, Mike; Pavlenko, Elena P; Kuramoto, Tetsuya; Miyashita, Atsushi; Pickard, Roger D; Hynek, Tomas; Dvorak, Shawn; Stubbings, Rod; Muyllaert, Eddy

    2010-01-01

    As an extension of the project in Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 61 SU UMa-type dwarf novae mainly observed during the 2009-2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (2009): the presence of stages A-C, as well as the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in period derivatives for systems with superhump periods longer than 0.075 d between this study and Kato et al. (2009). We suggest that this difference is possibly caused by the relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. The close correlation between the beat period and superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of superh...

  1. Effect of Water Invasion on Outburst Predictive Index of Low Rank Coals in Dalong Mine.

    Directory of Open Access Journals (Sweden)

    Jingyu Jiang

    Full Text Available To improve the coal permeability and outburst prevention, coal seam water injection and a series of outburst prevention measures were tested in outburst coal mines. These methods have become important technologies used for coal and gas outburst prevention and control by increasing the external moisture of coal or decreasing the stress of coal seam and changing the coal pore structure and gas desorption speed. In addition, techniques have had a significant impact on the gas extraction and outburst prevention indicators of coal seams. Globally, low rank coals reservoirs account for nearly half of hidden coal reserves and the most obvious feature of low rank coal is the high natural moisture content. Moisture will restrain the gas desorption and will affect the gas extraction and accuracy of the outburst prediction of coals. To study the influence of injected water on methane desorption dynamic characteristics and the outburst predictive index of coal, coal samples were collected from the Dalong Mine. The methane adsorption/desorption test was conducted on coal samples under conditions of different injected water contents. Selective analysis assessed the variations of the gas desorption quantities and the outburst prediction index (coal cutting desorption index. Adsorption tests indicated that the Langmuir volume of the Dalong coal sample is ~40.26 m3/t, indicating a strong gas adsorption ability. With the increase of injected water content, the gas desorption amount of the coal samples decreased under the same pressure and temperature. Higher moisture content lowered the accumulation desorption quantity after 120 minutes. The gas desorption volumes and moisture content conformed to a logarithmic relationship. After moisture correction, we obtained the long-flame coal outburst prediction (cutting desorption index critical value. This value can provide a theoretical basis for outburst prediction and prevention of low rank coal mines and similar

  2. Effect of Water Invasion on Outburst Predictive Index of Low Rank Coals in Dalong Mine.

    Science.gov (United States)

    Jiang, Jingyu; Cheng, Yuanping; Mou, Junhui; Jin, Kan; Cui, Jie

    2015-01-01

    To improve the coal permeability and outburst prevention, coal seam water injection and a series of outburst prevention measures were tested in outburst coal mines. These methods have become important technologies used for coal and gas outburst prevention and control by increasing the external moisture of coal or decreasing the stress of coal seam and changing the coal pore structure and gas desorption speed. In addition, techniques have had a significant impact on the gas extraction and outburst prevention indicators of coal seams. Globally, low rank coals reservoirs account for nearly half of hidden coal reserves and the most obvious feature of low rank coal is the high natural moisture content. Moisture will restrain the gas desorption and will affect the gas extraction and accuracy of the outburst prediction of coals. To study the influence of injected water on methane desorption dynamic characteristics and the outburst predictive index of coal, coal samples were collected from the Dalong Mine. The methane adsorption/desorption test was conducted on coal samples under conditions of different injected water contents. Selective analysis assessed the variations of the gas desorption quantities and the outburst prediction index (coal cutting desorption index). Adsorption tests indicated that the Langmuir volume of the Dalong coal sample is ~40.26 m3/t, indicating a strong gas adsorption ability. With the increase of injected water content, the gas desorption amount of the coal samples decreased under the same pressure and temperature. Higher moisture content lowered the accumulation desorption quantity after 120 minutes. The gas desorption volumes and moisture content conformed to a logarithmic relationship. After moisture correction, we obtained the long-flame coal outburst prediction (cutting desorption) index critical value. This value can provide a theoretical basis for outburst prediction and prevention of low rank coal mines and similar occurrence conditions

  3. Lectures on Classical Integrability

    CERN Document Server

    Torrielli, Alessandro

    2016-01-01

    We review some essential aspects of classically integrable systems. The detailed outline of the lectures consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schroedinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel'fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  4. The progenitor and remnant of the helium nova V445 Puppis

    CERN Document Server

    Goranskij, V P; Zharova, A V; Kroll, P; Barsukova, E A

    2010-01-01

    V445 Pup was a peculiar nova with no hydrogen spectral lines during the outburst. The spectrum contained strong emission lines of carbon, oxygen, calcium, sodium, and iron. We have performed digital processing of photographic images of the V445 Pup progenitor using astronomical plate archives. The brightness of the progenitor in the B band was 14.3 mag. It was a periodic variable star, its most probable period being 0.650654+/-0.000011 day. The light curve shape suggests that the progenitor was a common-envelope binary with a spot on the surface and variable surface brightness. The spectral energy distribution of the progenitor between 0.44 and 2.2 micrometers was similar to that of an A0V type star. After the explosion in 2001, the dust was formed in the ejecta, and the star became a strong infrared source. This resulted in the star's fading below 20 mag in the V band. Our CCD BVR observations acquired between 2003 and 2009 suggest that the dust absorption minimum finished in 2004, and the remnant reappeared...

  5. VLBI observations of RS Oph - a recurrent nova with non-spherical ejection

    International Nuclear Information System (INIS)

    VLBI observations of the recurrent nova RS Oph were carried out on two occasions following its 1985 outburst. The 1.7-GHz observations have revealed a linear, multicomponent radio source with total angular extent of 200 mas. For a distance of 1.6 kpc, the implied maximum expansion velocity is 3600 km s-1. The majority of the emission, however, is contained in a central component with dimension of 60 mas. A source geometry consisting of a compact core plus more extended component is also suggested by the 5-GHz results. The brightness temperature of the radio emission is > 107 K. The possibility that the low-frequency emission is due to bremsstrahlung from a 107 K plasma is ruled out by the observed level of X-ray emission. The low-frequency radiation process is therefore non-thermal, and probably synchrotron emission. Our analysis suggests that the dual-component radio spectrum of RS Oph is composed of a rapidly evolving, low-frequency non-thermal component plus a high-frequency thermal component which reaches peak flux density much later than the non-thermal emission. (author)

  6. Characterizing the QPO Behavior of the X-ray Nova XTE J1550--564

    CERN Document Server

    Remillard, R A; Muno, M P; McClintock, J E; Remillard, Ronald A.; Sobczak, Gregory J.; Muno, Michael P.; Clintock, Jeffrey E. Mc

    2001-01-01

    For all 209 RXTE observations of the X-ray nova XTE J1550-564 during its major outburst of 1998-1999, we have analyzed the X-ray power spectra, phase lags, and coherence functions. The phase lags and coherence measures are used to distinguish three types of low-frequency QPOs (one more than those reported by Wijnands, Homan, & van der Klis 1999). For the most common type, the phase lag is correlated with both the QPO frequency and the amplitude. The physical significance of the QPO types is evident in the relationships between QPO properties and the apparent temperature and flux from the accretion disk. There is also a clear pattern in how the QPO types relate to the presence of high-frequency QPOs. In general, both the amplitude and the Q value (freq./FWHM) of low-frequency QPOs decrease as the high-frequency oscillations increase in frequency (100 to 284 Hz) and in Q value. We speculate that the antagonism between low-frequency and high-frequency QPOs arises from competing structures in a perturbed accr...

  7. The Spin of The Black Hole in the X-ray Binary Nova Muscae 1991

    CERN Document Server

    Chen, Zihan; McClintock, Jeffrey E; Steiner, James F; Wu, Jianfeng; Xu, Weiwei; Orosz, Jerome; Xiang, Yanmei

    2016-01-01

    The bright soft X-ray transient Nova Muscae 1991 was intensively observed during its entire 8-month outburst using the Large Area Counter (LAC) onboard the Ginga satellite. Recently, we obtained accurate estimates of the mass of the black hole primary, the orbital inclination angle of the system, and the distance. Using these crucial input data and Ginga X-ray spectra, we have measured the spin of the black hole using the continuum-fitting method. For four X-ray spectra of extraordinary quality we have determined the dimensionless spin parameter of the black hole to be a/M = 0.63 (-0.19, +0.16) (1 sigma confidence level), a result that we confirm using eleven additional spectra of lower quality. Our spin estimate challenges two published results: It is somewhat higher than the value predicted by a proposed relationship between jet power and spin; and we find that the spin of the black hole is decidedly prograde, not retrograde as has been claimed.

  8. The 1988 glacial lake outburst flood in Guangxieco Lake, Tibet, China

    Science.gov (United States)

    Liu, J.-J.; Cheng, Z.-L.; Li, Y.

    2014-11-01

    The 1988 glacial lake outburst flood (GLOF) in Guangxieco Lake is studied based on geomorphological evidence, interviews with local residents, field surveys in 1990 and 2007, and satellite images from different years. The findings are as follows. (1) The outburst event was caused by two major factors, namely, intense pre-precipitation and persistent high temperatures before the outburst and the low self-stability of the terminal moraine dam as a result of perennial piping. (2) The GLOF, with the peak discharge rate of 1270 m3 s-1, evolved along Midui Valley in the following order: sediment-laden flow, viscous debris flow, non-viscous debris flow, and sediment-laden flood, which was eventually blocked by Palongzangbu River. (3) A comparison between the conditions during the outburst in 1988 and the present conditions suggests a small possibility of a future outburst unless drastic changes occur in landscape and climate. Reconstructing the outburst conditions and the GLOF processes is helpful in assessing a potential outburst in glacier lakes in Tibet.

  9. Glacier lake outburst floods of the Guangxieco Lake in 1988 in Tibet, China

    Directory of Open Access Journals (Sweden)

    J. J. Liu

    2013-09-01

    Full Text Available Glacial lake outburst floods (GLOFs have become more frequent and attracted more and more attention under conditions of global warming. However, there are few observations of the reasons for outbursts and their processes because of their unexpected occurrence and their inaccessible location in high-elevation areas. The GLOF of the Guangxieco Lake, which is the only outburst lake below an elevation of 4000 m in Tibet, provides a case study for discussing the reasons for outbursts. This paper reconstructs the process in detail using geomorphological evidence, interviews of the local inhabitants, archive material and satellite images. It was found that: (1 There were three main reasons for the GLOF in 1988: intense pre-precipitation and persistent high temperatures before the outburst, ice avalanche by rapid movement of the Gongzo Glacier and low self-stability of the end-moraine dam by perennial piping. (2 The GLOF with the peak discharge of 1270 m3 s-1 was evolved along the Midui Valley following sediment-laden flow–non-viscous debris flow–viscous debris flow–non-viscous debris flow–sediment-laden flood. Eventually the sediment-laden floods blocked the Palongzangbu River. (3 Comparing the conditions for the outburst in 1988 and at present, the possibility of a future outburst is thought to be small unless the glacier moves rapidly again.

  10. Discovery of an eclipsing dwarf nova in the ancient nova shell Te 11

    CERN Document Server

    Miszalski, Brent; Littlefair, Stuart P; Warner, Brian; Boffin, Henri M J; Corradi, Romano L M; Jones, David; Motsoaledi, Mokhine; Rodríguez-Gil, Pablo; Sabin, Laurence; Santander-García, Miguel

    2015-01-01

    We report on the discovery of an eclipsing dwarf nova (DN) inside the peculiar, bilobed nebula Te 11. Modelling of high-speed photometry of the eclipse finds the accreting white dwarf to have a mass 1.18 M$_\\odot$ and temperature 13 kK. The donor spectral type of M2.5 results in a distance of 330 pc, colocated with Barnard's loop at the edge of the Orion-Eridanus superbubble. The perplexing morphology and observed bow shock of the slowly-expanding nebula may be explained by strong interactions with the dense interstellar medium in this region. We match the DN to the historic nova of 483 CE in Orion and postulate that the nebula is the remnant of this eruption. This connection supports the millennia time scale of the post-nova transition from high to low mass-transfer rates. Te 11 constitutes an important benchmark system for CV and nova studies as the only eclipsing binary out of just three DNe with nova shells.

  11. Possible optical Nova in M 31

    Science.gov (United States)

    Pietsch, W.; Burwitz, V.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D.

    2007-11-01

    We report the discovery of an optical nova candidate in M 31 on two 8*60sec stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) Livermore Optical Transient Imaging System (Super- LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2007 Nov 2.28 and 2.37 with respective magnitudes of 16.9 and 17.0. The position for the nova candidate is RA = 00h42m37.29s, Dec = +41d17'10.3" (J2000, accuracy of 0.2"), which is 1' 19" west and 1' 2" north of the core of M 31.

  12. Optical Nova Candidate in M 31

    Science.gov (United States)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-06-01

    We report the discovery of an optical nova candidate in M 31 on two 11x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 June 14.46 and 16.46 UT with respective magnitudes of 18.0 and 17.7. The position for the nova candidate is RA = 00h42m37.72s, Dec = +41d12'30.0"(J2000, accuracy of 0.3"), which is 1'14" west and 3'39" south of the core of M 31. All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al.

  13. Possible new optical Nova in M 31

    Science.gov (United States)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Hartmann, D.; Milne, P.; Williams, G.

    2007-12-01

    We report the discovery of an optical nova candidate in M 31 on two 8*60sec stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) Livermore Optical Transient Imaging System (Super- LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2007 Dec 18.19 and 18.30 with respective magnitudes of 17.2 and 17.4. The position for the nova candidate is RA = 00h41m54.96s, Dec = +41d09'47.3" (J2000, accuracy of 0.3"), which is 9' 17" west and 6' 22" south of the core of M 31.

  14. Quark Nova Model for Fast Radio Bursts

    CERN Document Server

    Shand, Zachary; Koning, Nico; Ouyed, Rachid

    2015-01-01

    FRBs are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via $\\beta$-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm$^{-3}$ pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of $\\beta$-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FR...

  15. Grand Banks wins Terra Nova sweeps

    International Nuclear Information System (INIS)

    The Grand Bank Alliance of Companies, which includes Brown and Root and Agra Industries, Haliburton Energy Services, Doris Engineering, FMC Corporation and PCL Constructors, have been awarded the primary fabrication contract by Petro-Canada to build a floating production and storage vessel for the Terra Nova oil project. The total pre-production costs are estimated at $1.6 billion; the first oil is scheduled for 1999. The contract involves construction of a double-hulled floating production, storage and offloading vessel, designed to process up to 150,000 barrels of crude per day, and storing up to one million barrels. In addition to Terra Nova, Brown and Root and Agra also have project management contracts building infrastructure for Sable Island natural gas

  16. Nova Scotia Power Corporation annual report, 1993

    International Nuclear Information System (INIS)

    The Nova Scotia Power Corporation supplies electric power to over 410,000 customers in Nova Scotia. In 1993, over 8.8 million kWh of power was sold, 70-80% of which came from indigenous coal and hydroelectric sources, and the rest from oil-fired power stations. Other activities described in this report include a program to dispose of material contaminated by polychlorinated biphenyls, and a program to limit sulfur dioxide emissions to no greater than 160,000 tonnes/y by 1994. The latter program will rely on the use of circulating fluidized bed combustion in new coal-fired power stations being planned or constructed. Financial statements are also included. 6 figs., 3 tabs

  17. Grassmannians of classical buildings

    CERN Document Server

    Pankov, Mark

    2010-01-01

    Buildings are combinatorial constructions successfully exploited to study groups of various types. The vertex set of a building can be naturally decomposed into subsets called Grassmannians. The book contains both classical and more recent results on Grassmannians of buildings of classical types. It gives a modern interpretation of some classical results from the geometry of linear groups. The presented methods are applied to some geometric constructions non-related to buildings - Grassmannians of infinite-dimensional vector spaces and the sets of conjugate linear involutions. The book is self

  18. Davidson and classical pragmatism

    Directory of Open Access Journals (Sweden)

    Paula Rossi

    2007-06-01

    Full Text Available In this paper I wish to trace some connections between Donald Davidson's work (1917-2003 and two major representatives of the classical pragmatist movement: Charles S. Peirce (1839-1914 and William James (1842-1910. I will start with a basic characterization of classical pragmatism; then, I shall examine certain conceptions in Peirce's and James' pragmatism, in order to establish affinities with Davidson´s thought. Finally, and bearing in mind the previous con-nections, I will reflect briefly on the relevance –often unrecognized- of classical pragmatist ideas in the context of contemporary philosophi-cal discussions.

  19. The SuperNova Early Warning System

    OpenAIRE

    Scholberg, K.

    2008-01-01

    A core collapse in the Milky Way will produce an enormous burst of neutrinos in detectors world-wide. Such a burst has the potential to provide an early warning of a supernova's appearance. I will describe the nature of the signal, the sensitivity of current detectors, and SNEWS, the SuperNova Early Warning System, a network designed to alert astronomers as soon as possible after the detected neutrino signal.

  20. Nova power systems: status and operating experience

    International Nuclear Information System (INIS)

    This paper describes the pulse power systems that are used in these lasers; the status and the operating experiences. The pulsed power system for the Nova Laser is comprised of several distinct technology areas. The large capacitor banks for driving flashlamps that excite the laser glass is one area, the fast pulsers that drive pockels cell shutters is another area, and the contol system for the pulsed power is a third. This paper discusses the capacitor banks and control systems

  1. Desni ekstremizam, radikalizam i zapadnoeuropska Nova desnica

    OpenAIRE

    Velički, Damir

    2010-01-01

    U ovom se radu polazi od pojma političkog ekstremizma koji karakterizira odbijanje temeljnih vrijednosti demokratske ustavne države te se, nadalje, nakon definiranja strukturnih značajki desnog ekstremizma on razgraničuje od srodnog pojma desnog radikalizma. U nastavku se analizira pojam tzv. Nove desnice te njezina prisutnost u Francuskoj, Italiji, Velikoj Britaniji i SR Njemačkoj. Pojam Nova desnica prikladan je ako se njime opisuju intelektualna strujanja koja rade na ide...

  2. Mechanical construction of the 22 Nova laser

    International Nuclear Information System (INIS)

    The Nova laser system for Inertial Confinement Fusion studies at Lawrence Livermore National Laboratory is under construction and will be completed October 1984 with first operations scheduled for 1985. This system is the largest precision opto-mechanical engineering system ever built. Major engineering and subsystems are mechanical, optical, and electrical power. A series of system technologies include alignment, diagnostics, target, frequency conversion, and controls. This paper will only discuss the mechanical system

  3. Research on risk evaluation of mine gas outburst fatalness in Xiangshui Mine

    Institute of Scientific and Technical Information of China (English)

    GUI Xiang-you; YU Zhong-ming

    2008-01-01

    The danger degree evaluation of coal and gas outburst is mainly evaluating spot risk using the safety examination table and the evaluation value can be found. According to factors influence coal and gas outburst majorth were qualitative or fuzzy similar factors, used fuzzy gathering classification method for the coal and the gas outburst analysis, established fuzzy model, according to the model adopted the fuzzy similar selective principle proceeding evaluated. Two kinds methods join together analysis can raise on the accuracy rate of the prediction.

  4. Research on coal structure indices to coal and gas outbursts in Pingdingshan Mine Area, China

    Institute of Scientific and Technical Information of China (English)

    郭德勇; 宋广太; 库明欣

    2002-01-01

    According to the feature that coal and gas outbursts is controlled by coal structure in Pingdingshan mine area, based on the study of the distribution law of disturbed coal in Mine Area and the macroscopic characteristics of coal structure, the characteristics and genesis to micro-pore of disturbed coal, the relationship between the type of coal structure and gas parameter, and the structural feature of coal at outbursts sites are mainly explored in this paper. Further, the steps and methods are put forward that coal structure indices applied to forecast coal and gas outbursts.

  5. Introduction to the Nova technical contract

    Energy Technology Data Exchange (ETDEWEB)

    Lindl, J.D.; Kilkenny, J.D.

    1996-06-01

    The 1990 National Academy of Sciences (NAS) final report recommended proceeding with the construction of a 1-to 2-MJ Nd-doped glass laser designed to achieve ignition in the laboratory (a laser originally called the Nova Upgrade, but now called the National Ignition Facility, or NIF, and envisioned as a national user facility). As a prerequisite, the report recommended completion of a series of target physics objectives on the Nova laser in use at the Lawrence Livermore National Laboratory (LLNL). Meeting these objectives, which were called the Nova Technical Contract (NTC), would demonstrate (the Academy committee believed) that the physics of ignition targets was understood well enough that the laser requirements could be accurately specified. Completion of the NTC objectives was given the highest priority (it was Recommendation 1.1) in the NAS report. The NAS committee also recommended a concentrated effort on advanced target design for ignition. As recommended in the report, completion of these objectives has been the joint responsibility of LLNL and the Los Alamos National Laboratory. Most of the articles in this issue of the ICF Quarterly were written jointly by scientists from both institutions. The original NTC objectives have been largely met. This Introduction summarizes those objectives and their motivation in the context of the requirements for ignition.

  6. Physics of classical electromagnetism

    CERN Document Server

    Fujimoto, Minoru

    2007-01-01

    The classical electromagnetism described by the Maxwell equations constitutes a fundamental law in contemporary physics. Even with the advent of sophisticated new materials, the principles of classical electromagnetism are still active in various applied areas in today’s advanced communication techniques. Physics of Classical Electromagnetism, by Minoru Fujimoto, is written with concise introductory arguments emphasizing the original field concept, with an aim at understanding objectives in modern information technology. Following basic discussions of electromagnetism with a modernized approach, this book will provide readers with an overview of current problems in high-frequency physics. To further the reader’s understanding of the concepts and applications discussed, each illustration within the book shows the location of all active charges, and the author has provided many worked-out examples throughout the book. Physics of Classical Electromagnetism is intended for students in physics and engineering ...

  7. Injuries in classical ballet.

    Science.gov (United States)

    Quirk, R

    1984-11-01

    The specialised medical knowledge about dancers' injuries is negligible compared with that which surrounds sports medicine. The author discusses his experience in the management of more than 2000 injuries sustained by dancers of classical ballet. PMID:6151832

  8. Classical and Quantum Intertwine

    OpenAIRE

    Blanchard, Ph.; Jadczyk, A.

    1993-01-01

    Model interactions between classical and quantum systems are briefly discussed. These include: general measurement-like couplings, Stern-Gerlach experiment, model of a counter, quantum Zeno effect, SQUID-tank model.

  9. Microseism Monitoring System for Coal and Gas Outburst

    Directory of Open Access Journals (Sweden)

    Li Zhenbi

    2012-09-01

    Full Text Available The outburst forecast of coal and gas is a complex system engineering. On the basis of the analysis of microseism monitoring principle, a simplex positioning algorithm for microseism monitoring is designed; a mine microseism monitoring system is established to canalize mine microseism. Mechanism of the error producing and noise reduction measures is studied. We can analyze the data of the microseism monitoring to find coal or rock vibration caused by mining activities. Microseism monitoring system can capture real-time positioning information. It also can timely, accurately monitor and position these microseism events and the mining microseism event, which provide the pressure monitoring, the prediction of gas outstanding and the next step gas coal bed mining monitoring with reference experience.

  10. Spectral analysis of SMC X-2 during its 2015 outburst

    Science.gov (United States)

    La Palombara, N.; Sidoli, L.; Pintore, F.; Esposito, P.; Mereghetti, S.; Tiengo, A.

    2016-05-01

    We report on the results of XMM-Newton and Swift observations of SMC X-2 during its last outburst in 2015 October, the first one since 2000. The source reached a very high luminosity (L ˜ 1038 erg s-1), which allowed us to perform a detailed analysis of its timing and spectral properties. We obtained a pulse period Pspin = 2.372267(5) s and a characterization of the pulse profile also at low energies. The main spectral component is a hard (Γ ≃ 0) power-law model with an exponential cut-off, but at low energies we detected also a soft (with kT ≃ 0.15 keV) thermal component. Several emission lines are present in the spectrum. Their identification with the transition lines of highly ionized N, O, Ne, Si, and Fe suggests the presence of photoionized matter around the accreting source.

  11. Spectral analysis of SMC X-2 during its 2015 outburst

    CERN Document Server

    La Palombara, N; Pintore, F; Esposito, P; Mereghetti, S; Tiengo, A

    2016-01-01

    We report on the results of Swift and XMM-Newton observations of SMC X-2 during its last outburst in 2015 October, the first one since 2000. The source reached a very high luminosity ($L \\sim 10^{38}$ erg s$^{-1}$), which allowed us to perform a detailed analysis of its timing and spectral properties. We obtained a pulse period $P_{\\rm spin}$ = 2.372267(5) s and a characterization of the pulse profile also at low energies. The main spectral component is a hard ($\\Gamma \\simeq 0$) power-law model with an exponential cut-off, but at low energies we detected also a soft (with kT $\\simeq$ 0.15 keV) thermal component. Several emission lines can be observed at various energies. The identification of these features with the transition lines of highly ionized N, O, Ne, Si, and Fe suggests the presence of photoionized matter around the accreting source.

  12. Simultaneous Multiwavelength Observations of Markarian 421 During Outburst

    CERN Document Server

    Perez, I de la Calle; Rodríguez, P

    2009-01-01

    We report on the results of two coordinated multiwavelength campaigns that focused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These campaigns obtained UV and X-ray data using the XMM-Newton satellite, while the gamma-ray data were obtained utilizing three imaging atmospheric Cerenkov telescopes, the Whipple 10m telescope and VERITAS, both based in Arizona, as well as the MAGIC telescope, based on La Palma in the Canary Islands. The coordinated effort between the gamma-ray groups allowed for truly simultaneous data in UV/X-ray/gamma-ray wavelengths during a significant portion of the XMM-Newton observations. This simultaneous coverage allowed for a reliable search for correlations between UV, X-ray and gamma-ray variability over the course of the observations. Investigations of spectral hysteresis and modeling of the spectral energy distributions are also presented.

  13. SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS OF MARKARIAN 421 DURING OUTBURST

    International Nuclear Information System (INIS)

    We report on the results of two coordinated multiwavelength campaigns that focused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These campaigns obtained UV and X-ray data using the XMM-Newton satellite, while the gamma-ray data were obtained utilizing three imaging atmospheric Cerenkov telescopes, the Whipple 10 m telescope and VERITAS, both based in Arizona, as well as the MAGIC telescope, based on La Palma in the Canary Islands. The coordinated effort between the gamma-ray groups allowed for truly simultaneous data in UV/X-ray/gamma-ray wavelengths during a significant portion of the XMM-Newton observations. This simultaneous coverage allowed for a reliable search for correlations between UV, X-ray, and gamma-ray variability over the course of the observations. Investigations of spectral hysteresis and modeling of the spectral energy distributions are also presented.

  14. The Early ALMA View of the FU Ori Outburst System

    Science.gov (United States)

    Hales, A. S.; Corder, S. A.; Dent, W. R. D.; Andrews, S. M.; Eisner, J. A.; Cieza, L. A.

    2015-10-01

    We have obtained ALMA Band 7 observations of the FU Ori outburst system at a 0.″6 × 0.″5 resolution to measure the link between the inner disk instability and the outer disk through submillimeter continuum and molecular line observations. Our observations detect continuum emission that can be well-modeled by two unresolved sources located at the position of each binary component. The interferometric observations recover the entire flux reported in previous single-dish studies, ruling out the presence of a large envelope. Assuming that the dust is optically thin, we derive disk dust masses of 2 × 10-4 M⊙ and 8× {10}-5 M⊙ for the north and south components, respectively. We place limits on the disks’ radii of r FU Ori-type episodes.

  15. Outburst Risk of Barrier Lakes in Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    CHENG Genwei; WANG Xiaodan; HE Xiubin; FAN Jihui; FAN Jianrong

    2008-01-01

    34 barrier lakes induced by earthquake have been formed by wedged debris on the river channels after a massive earthquake happening on May 12 in Sichuan, China. Among them, the Tangjiashan Barrier Lake is the largest one. It faces very urgent risk of dam breaking when water level reaches the top and begins overflow in case of storm rainfalls and continually aftershocks, threatening already devastated cities and villages with about 1.5 million people downstream. The outburst of a similar barrier lake occurred in the Minjiang River in 1933, causing a catastrophic flood. Risk analysis indicates that not all barrier lakes are highly dangerous. Only those lakes with very high dams and water to be filled up in short period need to be dealt with immediately.

  16. SAX J2103.5+4545 in outburst

    DEFF Research Database (Denmark)

    Galis, R.; Beckmann, V.; Bianchin, V.;

    2008-01-01

    We report an intense hard X-ray outburst detected from the Be/ neutron star HMXB SAX J2103.5+4545 (Blay et al. 2004, A&A, 427, 293), which is known to be a pulsar. The source was detected during INTEGRAL observations of the Galactic Plane in the Cygnus region, starting at 2007-04-25T09:14 (UTC). ......). The source was detected by INTEGRAL IBIS/ISGRI within 60 ksec with a flux of (1.7 +- 0.1)E-09 erg/cm**2/sec in the 20-40 keV energy band, and with (5.3 +- 0.7)E-10 erg/cm**2/sec at 40-80 keV....

  17. Flickering of the symbiotic variable CH Cygni during outburst

    International Nuclear Information System (INIS)

    High-speed and conventional BVRI photometry are reported for the bright symbiotic variable CH Cygni (M6 IIIe), obtained during the course of a recent outburst. Unlike the quiescent symbiotic stars, the presence of flickering similar in nature to that seen in the cataclysmic variables has been confirmed during this active phase. The BVRI photometry for a sample of stars in the field is used to derive the reddening and the distance to CH Cyg. A composite energy distribution is derived from 0.35 to 11.0 μm which clearly establishes the existence of a variable, blue continuum. The lack of variability in the near infrared suggests that the blue continuum arises from a hot companion. A binary model including a subluminous hot companion accreting material from the stellar wind of an SRa variable is discussed to account for the observed photometric properties. (author)

  18. High Resolution Optical Spectra of HBC 722 after Outburst

    CERN Document Server

    Lee, Jeong-Eun; Lee, Sang-Gak; Sung, Hyun-Il; Lee, Byeong-Cheol; Sung, Hwankyung; Green, Joel D; Jeon, Young-Beom

    2011-01-01

    We report the results of our high resolution optical spectroscopic monitoring campaign ($\\lambda$ = 3800 -- 8800 A, R = 30000 -- 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between 2010 November 26 and 2010 December 29 and FU Orionis itself on 2011 January 26. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 A. We resolve the H$\\alpha$ and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and redshifted broad features.

  19. Classical confined particles

    Science.gov (United States)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.

  20. Davidson and classical pragmatism

    OpenAIRE

    Paula Rossi

    2007-01-01

    In this paper I wish to trace some connections between Donald Davidson's work (1917-2003) and two major representatives of the classical pragmatist movement: Charles S. Peirce (1839-1914) and William James (1842-1910). I will start with a basic characterization of classical pragmatism; then, I shall examine certain conceptions in Peirce's and James' pragmatism, in order to establish affinities with Davidson´s thought. Finally, and bearing in mind the previous con-nections, I will reflect brie...

  1. Nonmaximal neutrino mixing at NOvA from nonstandard interactions

    CERN Document Server

    Liao, Jiajun; Whisnant, Kerry

    2016-01-01

    Muon neutrino disappearance measurements at NOvA suggest that maximal \\theta_{23} is excluded at the 2.5\\sigma CL. This is in mild tension with T2K data which prefer maximal mixing. Considering that NOvA has a much longer baseline than T2K, we point out that the apparent departure from maximal mixing in NOvA may be a consequence of nonstandard neutrino propagation in matter.

  2. Orbital Period Change in Outburst: T Pyx Goes Rogue

    Science.gov (United States)

    Patterson, J.; Oksanen, A.; Monard, B.

    2013-01-01

    We summarize the results of our 1996-2013 study of the light curve of the recurrent nova T Pyx, based on ~3000 hours of coverage with small (0.3 m) telescopes. The star's light curve at quiescence (V=15, Mv=+1) is essentially that reported in our first paper (Patterson et al. 1998, PASP 110, 380): a broad and shallow (0.1 mag) dip occurring strictly on schedule with a mean period of 0.07622 d, but with period increasing smoothly on a timescale of 3x105 yrs.

  3. On the diversity and similarity of outbursts of symbiotic binaries and cataclysmic variables

    CERN Document Server

    Skopal, Augustin

    2015-01-01

    Outbursts in two classes of interacting binary systems, the symbiotic stars (SSs) and the cataclysmic variables (CVs), show a number of similarities in spite of very different orbital periods. Typical values for SSs are in the order of years, whereas for CVs they are of a few hours. Both systems undergo unpredictable outbursts, characterized by a brightening in the optical by 1 - 3 and 7 - 15 mag for SSs and CVs, respectively. By modelling the multiwavelength SED of selected examples from both groups of these interacting binaries, I determine their basic physical parameters at a given time of the outburst evolution. In this way I show that the principal difference between outbursts of these objects is their violence, whereas the ionization structure of their ejecta is basically very similar. This suggests that the mechanism of the mass ejection by the white dwarfs in these systems is also similar.

  4. Spectral and Temporal Properties of MAXI J1836-194 during 2011 Outburst

    CERN Document Server

    Jana, A; Mondal, S; Chakrabarti, S K; Molla, A A; Chatterjee, D

    2015-01-01

    We study black hole candidate (BHC) MAXI~J1836-194 during its 2011 outburst with Two Component Advective Flow (TCAF) model using RXTE/PCU2 data in $2.5-25$~keV band. From spectral fit, accretion flow parameters such as Keplerian disk rate ($\\dot{m_d}$), sub-Keplerian halo rate ($\\dot{m_h}$), shock location ($X_{s}$) and compression ratio (R) are extracted directly. During the entire phase of the outburst, quasi-periodic oscillations (QPOs) are observed sporadically. From the nature of the variation of accretion rate ratio (ARR=$\\dot{m_h}$ / $\\dot{m_d}$) and QPOs, entire period of the outburst is classified in two spectral states, such as, hard (HS), hard-intermediate (HIMS). Unlike other transient BHCs, no signature of soft (SS) and soft-intermediate (SIMS) spectral states are observed during entire phase of the outburst

  5. Development of a web-based, underground coalmine gas outburst information management system

    Energy Technology Data Exchange (ETDEWEB)

    Naj Aziz; Richard Caladine; Lucia Tome; Ken Cram; Devendra Vyas [University of Wollongong, NSW (Australia)

    2007-04-15

    The primary objective of this project was to develop an online coal mine outburst information management system to provide the coal mining industry with the necessary information and knowledge on outbursts via the World Wide Web. The Website has been constructed using the standard web format. Access to the site is by standard web browsers. The address of the site is http://www.uow.edu.au/eng/outburst. The website has 85 conference papers which were held in Australia, dating as far back as the 1980's, various seminar presentations, more than 250 references, a limited but important collection of international papers, direct links to ACARP and NERRDC publication lists, links to several leading organisations of particular interest in mine gas and outburst control. These links include both private and government organisations, and a forum for discussion.

  6. Inclination and relativistic effects in the outburst evolution of black hole transients

    OpenAIRE

    Munoz-Darias, T.; Coriat, M.; Plant, D. S.; Ponti, G.; Fender, R. P.; Dunn, R. J. H.

    2013-01-01

    We have systematically studied the effect of the orbital inclination in the outburst evolution of black hole transients. We have included all the systems observed by the Rossi X-ray Timing Explorer in which the thermal, accretion disc component becomes strongly dominant at some point of the outburst. Inclination is found to modify the shape of the tracks that these systems display in the colour/luminosity diagrams traditionally used for their study. Black hole transients seen at low inclinati...

  7. Swift observations of black hole candidate XTE J1752-223 during outburst

    OpenAIRE

    Curran, P. A.; Casella, P.; Maccarone, T.J.; Evans, P. A.; Landsman, W.; Krimm, H. A.; Brocksopp, C.; Still, M.

    2011-01-01

    Here we summarise the Swift broadband observations of the recently discovered X-ray transient and black hole candidate, XTE J1752-223,obtained over the period of outburst from October 2009 to June 2010. We offer a phenomenological treatment of the spectra as an indication of the canonical spectral state of the source during different periods of the outburst. We find that the high energy hardness-intensity diagrams over two separate bands follows the canonical behavior, confirming the spectral...

  8. Orbital parameters of V 0332+53 from 2015 giant outburst data

    CERN Document Server

    Doroshenko, V; Santangelo, A

    2015-01-01

    We present the updated orbital solution for a transient Be X-ray binary V 0332+53 currently undergoing a major outburst using the data from gamma-ray burst monitor onboard the Fermi mission. We model the observed changes in the spin-frequency of the pulsar and deduce the orbital parameters of the system significantly improving existing constrains. The intrinsic spin-up of the neutron star is found to be comparable to values observed in previous giant outburst.

  9. Classically-Controlled Quantum Computation

    OpenAIRE

    Perdrix, Simon; Jorrand, Philippe

    2004-01-01

    Quantum computations usually take place under the control of the classical world. We introduce a Classically-controlled Quantum Turing Machine (CQTM) which is a Turing Machine (TM) with a quantum tape for acting on quantum data, and a classical transition function for a formalized classical control. In CQTM, unitary transformations and measurements are allowed. We show that any classical TM is simulated by a CQTM without loss of efficiency. The gap between classical and quantum computations, ...

  10. Rock and water outburst and its prevention measure. Mizu tosshutsu to sono taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, S. (Nishimatsu Construction Co. Ltd., Tokyo (Japan)); Nakajima, I.; Ujihara, M. (Hokkaido University, Sapporo (Japan). Faculty of Engineering)

    1991-12-25

    With coal mines on the ebb, the technologies developed therefrom are beginning to fall into oblivion. Accordingly, a review was made from the present day viewpoint on the rock and water outbursts occurred several times at the Yubari Coal Mine at its development phase a water outburst accompanying rock outburst that occurs when a shaft gets close to a (high-pressure ground water bed). A fracture probability theory was used to determine the reason why a crater formed at a water outburst has a small opening and a great depth in the case of shales, and the other way around in the case of sand stones. The result was used in considering the specifications for water stopping constructions established in the past as the water outburst prevention measures, whereas such specifications having been improved on shales with the greatest uniformity were clarified to provide higher safety to other kinds of rocks. Examinations were also given on the flooding construction method used in constructing shaft bottom bulkheads as a provisional measure against a water outburst in a vertical shaft. This construction method could be applied to developing underground spaces at great depths. 8 refs., 16 figs., 6 tabs.

  11. Detection of an outburst one year prior to the explosion of SN 2011ht

    CERN Document Server

    Fraser, M; Kotak, R; Smartt, S J; Smith, K W; Polshaw, J; Drake, A J; Boles, T; Lee, C -H; Burgett, W S; Chambers, K C; Draper, P W; Flewelling, H; Hodapp, K W; Kaiser, N; Kudritzki, R -P; Magnier, E A; Price, P A; Tonry, J L; Wainscoat, R J; Waters, C

    2013-01-01

    Using imaging from the Pan-STARRS1 survey, we identify a precursor outburst at epochs 287 and 170 days prior to the reported explosion of the purported Type IIn supernova (SN) 2011ht. In the Pan-STARRS data, a source coincident with SN 2011ht is detected exclusively in the \\zps\\ and \\yps-bands. An absolute magnitude of M$_z\\simeq$-11.8 suggests that this was an outburst of the progenitor star. Unfiltered, archival Catalina Real Time Transient survey images also reveal a coincident source from at least 258 to 138 days before the main event. We suggest that the outburst is likely to be an intrinsically red eruption, although we cannot conclusively exclude a series of erratic outbursts which were observed only in the redder bands by chance. This is only the fourth detection of an outburst prior to a claimed SN, and lends credence to the possibility that many more interacting transients have pre-explosion outbursts, which have been missed by current surveys.

  12. Sudden End of X-Ray Outbursts around Periastron of Circinus X-1 Observed with MAXI

    CERN Document Server

    Asai, Kazumi; Matsuoka, Masaru; Sugizaki, Mutsumi; Nakahira, Satoshi; Negoro, Hitoshi; Nakajima, Motoki; Okazaki, Atsuo T

    2014-01-01

    MAXI/GSC observed 21 outbursts from Circinus X-1 between 2009 August and 2013 December. Although 14 outbursts showed ordinary gradual decays, in 7 outbursts we found sudden luminosity decrease in a time scale of a few hours around the periastron, and then the outbursts terminated. These sudden decreases started at the estimated luminosity of a few times $10^{37}$ erg s$^{-1}$ and reached to $\\lesssim3\\times10^{36}$ erg s$^{-1}$. We propose three interpretations for the sudden luminosity decrease: (1) the end of the outburst during the dip, (2) the propeller effect, and (3) the stripping effect by the stellar wind of the companion star. It is difficult to explain the phenomenon with any of these interpretations alone. The interpretation of (1) is possible for only two outbursts assuming rapid decay. The propeller effect (2) is expected to occur at a constant luminosity, which is incompatible with the observed facts. In wind stripping effect (3), the ram pressure of a typical stellar wind is not sufficient to b...

  13. Reflections of AGN Outbursts in the Gaseous Atmosphere of M87

    CERN Document Server

    Forman, W; Heinz, S; Owen, F; Eilek, J A; Vikhlinin, A; Markevitch, M L; Kraft, R; Churazov, E; Jones, C

    2003-01-01

    We combined deep Chandra, ROSAT HRI, and XMM-Newton observations of M87 to study the impact of AGN outbursts on its gaseous atmosphere. Many X-ray features appear to be a direct result of repetitive AGN outbursts. In particular, the X-ray cavities around the jet and counter jet are likely due to the expansion of radio plasma, while rings of enhanced emission at 14 and 17 kpc are probably shock fronts associated with outbursts that began 1-2\\times10^7 years ago. The effects of these shocks are also seen in brightenings within the prominent X-ray arms. On larger scales, ~50 kpc from the nucleus, depressions in the surface brightness may be remnants of earlier outbursts. As suggested for the Perseus cluster, our analysis of the energetics of the M87 outbursts argues that shocks may be the most significant channel for AGN energy input into the cooling flow atmospheres of galaxies, groups, and clusters. For M87, the mean power driving the shock outburst, 2.4\\times 10^{43} ergs/sec, is three times greater than the ...

  14. Nova as embedded operating system for cuban hardware Nova como sistema operativo embebido para hardware cubano

    Directory of Open Access Journals (Sweden)

    Mijail Hurtado Fedorovich

    2012-05-01

    Full Text Available This paper presents the results of the construction a an embedded operating system based on Nova, which provides the needed features to create the Cuban Thin Client, using as hardware component the Computer on a CID 300/9 Board designed by the Central Institute for Digital Research, obtaining the first version of Nova for the Advance RISC Machine  computer architecture and the first base operating system, stable and for general purposes for the CID 300/9. A state of the art of the currently most used embedded operating systems, the solution's structure, the methods and tools used for its development are presented. Este trabajo expone los resultados de construir un sistema operativo embebido basado en Nova, el cual brinda las funcionalidades necesarias para crear el Cliente Ligero Cubano, utilizando como componente de hardware, la Computadora en una Tarjeta CID 300/9 diseñada por el Instituto Central de Investigación Digital. Obteniéndose la primera versión de Nova para la arquitectura de computadora Advanced RISC Machine y el primer sistema operativo base, estable y de propósito general para la CID 300/9. Se expone un estado del arte de los sistemas operativos embebidos más utilizados actualmente; la estructura de la solución, los métodos y herramientas empleados para obtenerla.

  15. Nova como sistema operativo embebido para hardware cubano Nova as embedded operating system for cuban hardware

    Directory of Open Access Journals (Sweden)

    José Ernesto Torres Sánchez

    2012-05-01

    Full Text Available Este trabajo expone los resultados de construir un sistema operativo embebido basado en Nova, el cual brinda las funcionalidades necesarias para crear el Cliente Ligero Cubano, utilizando como componente de hardware, la Computadora en una Tarjeta CID 300/9 diseñada por el Instituto Central de Investigación Digital. Obteniéndose la primera versión de Nova para la arquitectura de computadora Advanced RISC Machine y el primer sistema operativo base, estable y de propósito general para la CID 300/9. Se expone un estado del arte de los sistemas operativos embebidos más utilizados actualmente; la estructura de la solución, los métodos y herramientas empleados para obtenerla.This paper presents the results of the construction a an embedded operating system based on Nova, which provides the needed features to create the Cuban Thin Client, using as hardware component the Computer on a CID 300/9 Board designed by the Central Institute for Digital Research, obtaining the first version of Nova for the Advance RISC Machine  computer architecture and the first base operating system, stable and for general purposes for the CID 300/9. A state of the art of the currently most used embedded operating systems, the solution's structure, the methods and tools used for its development are presented.

  16. Learning Classical Music Club

    CERN Multimedia

    Learning Classical Music Club

    2010-01-01

    There is a new CERN Club called “Learning Classical Music at CERN”. We are aiming to give classical music lessons for different instruments (see link) for students from 5 to 100 years old. We are now ready to start our activities in the CERN barracks. We are now in the enrollment phase and hope to start lessons very soon ! Club info can be found in the list of CERN Club: http://user.web.cern.ch/user/Communication/SocialLifeActivities/Clubs/Clubs.html Salvatore Buontempo Club President

  17. A Single Classical Quark

    CERN Document Server

    Dzhunushaliev, V D

    1997-01-01

    The spherically symmetric solution in classical SU(3) Yang - Mills theory is found. It is supposed that such solution describes a classical quark. It is regular in origin and hence the interaction between two quarks is small on the small distance. The obtained solution has the singularity on infinity. It is possible that is the reason why the free quark cannot exist. Evidently, nonlocality of this object leads to the fact that in quantum chromodynamic the difficulties arise connected with investigation of quarks interaction on large distance.

  18. Classical Holographic Codes

    CERN Document Server

    Brehm, Enrico M

    2016-01-01

    In this work, we introduce classical holographic codes. These can be understood as concatenated probabilistic codes and can be represented as networks uniformly covering hyperbolic space. In particular, classical holographic codes can be interpreted as maps from bulk degrees of freedom to boundary degrees of freedom. Interestingly, they are shown to exhibit features similar to those expected from the AdS/CFT correspondence. Among these are a version of the Ryu-Takayanagi formula and intriguing properties regarding bulk reconstruction and boundary representations of bulk operations. We discuss the relation of our findings with expectations from AdS/CFT and, in particular, with recent results from quantum error correction.

  19. Classical mechanics with Maxima

    CERN Document Server

    Timberlake, Todd Keene

    2016-01-01

    This book guides undergraduate students in the use of Maxima—a computer algebra system—in solving problems in classical mechanics. It functions well as a supplement to a typical classical mechanics textbook. When it comes to problems that are too difficult to solve by hand, computer algebra systems that can perform symbolic mathematical manipulations are a valuable tool. Maxima is particularly attractive in that it is open-source, multiple-platform software that students can download and install free of charge. Lessons learned and capabilities developed using Maxima are easily transferred to other, proprietary software.

  20. Elementary classical hydrodynamics

    CERN Document Server

    Chirgwin, B H; Langford, W J; Maxwell, E A; Plumpton, C

    1967-01-01

    Elementary Classical Hydrodynamics deals with the fundamental principles of elementary classical hydrodynamics, with emphasis on the mechanics of inviscid fluids. Topics covered by this book include direct use of the equations of hydrodynamics, potential flows, two-dimensional fluid motion, waves in liquids, and compressible flows. Some general theorems such as Bernoulli's equation are also considered. This book is comprised of six chapters and begins by introducing the reader to the fundamental principles of fluid hydrodynamics, with emphasis on ways of studying the motion of a fluid. Basic c

  1. Classic Problems of Probability

    CERN Document Server

    Gorroochurn, Prakash

    2012-01-01

    "A great book, one that I will certainly add to my personal library."—Paul J. Nahin, Professor Emeritus of Electrical Engineering, University of New Hampshire Classic Problems of Probability presents a lively account of the most intriguing aspects of statistics. The book features a large collection of more than thirty classic probability problems which have been carefully selected for their interesting history, the way they have shaped the field, and their counterintuitive nature. From Cardano's 1564 Games of Chance to Jacob Bernoulli's 1713 Golden Theorem to Parrondo's 1996 Perplexin

  2. The first results from the NOVA experiment

    CERN Document Server

    CERN. Geneva

    2015-01-01

    The NOvA experiment measures neutrino oscillation phenomena over a baseline of 810 km using a narrow-band muon neutrino beam that has a peak energy near 2 GeV. With this configuration the experiment has sensitivity to the oscillation parameters that are the least known. Installation of the detector began almost 2 years ago and the collaboration has been recording data since then. The collaboration released its first measurements of neutrino oscillation phenomena this summer. The results of those measurements and the future prospects of the experiment will be discussed.

  3. Nova isolates noise to quieten stations

    International Nuclear Information System (INIS)

    This paper reviews a technique developed by Nova Corp., to help isolate and measure the acoustic power of individual components in a pipeline compressor and pumping station. The procedure calculates the sound pressure levels of each piece of equipment independently. Based on these measurements, a prediction can be made of the effect of various types of noise treatment techniques on the overall sound levels currently generated or proposed in a future project. This paper describes the equipment to measure the sound levels, techniques for actually measuring the compressor station or equipment area, and techniques used to generate a remediation plan

  4. Optical Nova Candidates in M 31

    Science.gov (United States)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-06-01

    We report the discovery of an optical nova candidate in M 31 on two 11x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 June 06.47 and 07.47 UT with respective magnitudes of 18.0 and 17.9.

  5. Fuse studies of dwarf novae during quiescence

    Directory of Open Access Journals (Sweden)

    E. M. Sion

    2004-01-01

    Full Text Available Hemos obtenido espectros de FUSE de varias novas enanas, los cuales revelan las propiedades de sus enanas blancas acrecientes, sus ritmos de acreci on durante la etapa de quietud y la naturaleza de las regiones capa borde/disco interior incluyendo la zona de acreci on en las enanas blancas. Entre los sistemas de los cuales presentamos resultados preliminares se encuentran BV Cen, WW Ceti, EY Cyg, SS Aur y VW Hyi. La contribuci on de estos estudios realizados con FUSE a nuestro entendimiento de la f sica de los discos de acreci on se enfatizar a dentro del contexto de la enana blaca y de la capa borde

  6. Supernova hydrodynamics experiments using the Nova laser

    Energy Technology Data Exchange (ETDEWEB)

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A. [Lawrence Livermore National Lab., CA (United States); Kane, J.; Arnett, D. [Arizona Univ., Tucson, AZ (United States). Stewart Observatory; Drake, R.P. [Michigan Univ., Ann Arbor, MI (United States); McCray, R. [Colorado Univ., Boulder, CO (United States)

    1997-04-01

    We are developing experiments using the Nova laser to investigate two areas of physics relevant to core-collapse supernovae (SN): (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications are discussed.

  7. 10% discount at Novae restaurants for students

    CERN Multimedia

    2016-01-01

    A 10% discount will be granted for students dining in restaurants 1 and 2 (on the Meyrin site) during the summer from 15 June 2016 to 15 September 2016.   A special badge will be issued by the respective secretariats if the student fulfils the following criteria:  Is under 25 years old; Is in possession of a student card issued by a University or college; Has a CERN contract > 1 month (Users, Summer Students, Trainees, etc). This badge and the CERN access card will have to be shown at the Novae restaurants in order to benefit from this discount.

  8. A study of law of coal-and-gas outburst & its controlling factors in Kailuan Mine Area,China

    Institute of Scientific and Technical Information of China (English)

    LI Jun-tao; GUO De-yong; ZHANG Zhi-yan

    2007-01-01

    On basis of an analysis of the geological condition,law of gas outburst and materials about coal-and-gas outburst,this paper summarized the characteristics associated with coal-and-gas outburst of Zhaogezhuang Mine and studied the factors controlling coal-and-gas outburst such as stress,coal structure and gas pressure,content of gas.Then.based on a comparison of effects of in-situ stresses,coal structure and gas on coal-and-gas outburst of Zhaogezhuang Mine,the paper concludes that the major geologicaI factors that control coal-and-gas outburst of Zhaogezhuang Mine are in-situ stresses and coal structure.

  9. Nuclear motion is classical

    CERN Document Server

    Frank, Irmgard

    2016-01-01

    The notion from ab-initio molecular dynamics simulations that nuclear motion is best described by classical Newton dynamics instead of the time-dependent Schr{\\"o}dinger equation is substantiated. In principle a single experiment should bring clarity. Caution is however necessary, as temperature dependent effects must be eliminated when trying to determine the existence of a zero-point energy.

  10. Strong Coupling and Classicalization

    CERN Document Server

    Dvali, Gia

    2016-01-01

    Classicalization is a phenomenon in which a theory prevents itself from entering into a strong-coupling regime, by redistributing the energy among many weakly-interacting soft quanta. In this way, the scattering process of some initial hard quanta splits into a large number of soft elementary processes. In short, the theory trades the strong coupling for a high-multiplicity of quanta. At very high energies, the outcome of such a scattering experiment is a production of soft states of high occupation number that are approximately classical. It is evident that black hole creation in particle collision at super-Planckian energies is a result of classicalization, but there is no a priory reason why this phenomenon must be limited to gravity. If the hierarchy problem is solved by classicalization, the LHC has a chance of detecting a tower of new resonances. The lowest-lying resonances must appear right at the strong coupling scale in form of short-lived elementary particles. The heavier members of the tower must b...

  11. Classical Iterative Methods

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    1. Berlin, Heidelberg: Springer-Verlag, 2013 - (Björm, E.), s. 205-224 ISBN 978-3-540-70528-4 Institutional support: RVO:68145535 Keywords : classical iterative methods * applied computational mathematics * encyclopedia Subject RIV: BA - General Mathematics http://www.springerreference.com/docs/ navigation .do?m=Encyclopedia+of+Applied+and+Computational+Mathematics+%28Mathematics+and+Statistics%29-book224

  12. Classical and quantum satisfiability

    CERN Document Server

    de Araújo, Anderson; 10.4204/EPTCS.81.6

    2012-01-01

    We present the linear algebraic definition of QSAT and propose a direct logical characterization of such a definition. We then prove that this logical version of QSAT is not an extension of classical satisfiability problem (SAT). This shows that QSAT does not allow a direct comparison between the complexity classes NP and QMA, for which SAT and QSAT are respectively complete.

  13. Why Study Classical Languages?

    Science.gov (United States)

    Lieberman, Samuel

    This speech emphasizes the significance of living literatures and living cultures which owe a direct debt to the Romans and the Greeks from whom they can trace their origins. After commenting on typical rejoinders to the question "Why study classical languages?" and poking fun at those who advance jaded, esoteric responses, the author dispels the…

  14. Classics in What Sense?

    Science.gov (United States)

    Camic, Charles

    2008-01-01

    They seem the perfect bookends for the social psychologist's collection of "classics" of the field. Two volumes, nearly identical in shape and weight and exactly a century old in 2008--each professing to usher "social psychology" into the world as they both place the hybrid expression square in their titles but then proceed to stake out the field…

  15. Mecanica Clasica (Classical Mechanics)

    OpenAIRE

    Rosu, H. C.

    1999-01-01

    First Internet graduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  16. Classical galactosaemia revisited

    NARCIS (Netherlands)

    A.M. Bosch

    2006-01-01

    Classical galactosaemia (McKusick 230400) is an: autosomal recessive disorder of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT; EC 2.7.712). Most patients present in the neonatal period, after ingestion of galactose, with jaundice, hepatospl

  17. Classical Mythology. Fourth Edition.

    Science.gov (United States)

    Morford, Mark P. O.; Lenardon, Robert J.

    Designed for students with little or no background in classical literature, this book introduces the Greek and Roman myths of creation, myths of the gods, Greek sagas and local legends, and presents contemporary theories about the myths. Drawing on Homer, Hesiod, Pindar, Vergil, and others, the book provides many translations and paraphrases of…

  18. Classicism and Romanticism.

    Science.gov (United States)

    Huddleston, Gregory H.

    1993-01-01

    Describes one teacher's methods for introducing to secondary English students the concepts of Classicism and Romanticism in relation to pictures of gardens, architecture, music, and literary works. Outlines how the unit leads to a writing assignment based on collected responses over time. (HB)

  19. Mecanica Clasica (Classical Mechanics)

    CERN Document Server

    Rosu, H C

    1999-01-01

    First Internet undergraduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  20. Classical electromagnetic radiation

    CERN Document Server

    Heald, Mark A

    2012-01-01

    Newly corrected, this highly acclaimed text is suitable for advanced physics courses. The author presents a very accessible macroscopic view of classical electromagnetics that emphasizes integrating electromagnetic theory with physical optics. The survey follows the historical development of physics, culminating in the use of four-vector relativity to fully integrate electricity with magnetism.

  1. The Classical Cake Problem

    Science.gov (United States)

    Nelson, Norman N.; Fisch, Forest N.

    1973-01-01

    Discussed are techniques of presentation and solution of the Classical Cake Problem. A frosted cake with a square base is to be cut into n pieces with the volume of cake and frosting the same for each piece. Needed are minimal geometric concepts and the formula for the volume of a prism. (JP)

  2. New optical nova candidate in M 31

    Science.gov (United States)

    Pietsch, W.; Henze, M.; Burwitz, V.; Kaur, A.; Hartmann, D. H.; Milne, P.; Williams, G.

    2010-12-01

    We report the discovery of a possible nova in M 31 on a 12x60s stacked R filter CCD image obtained with the robotic 60cm telescope with an E2V CCD (2kx2k, 13.5 micron sq. pixels) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2010 December 11.095 UT with magnitude of 16.6. The object is visible on all individual images. The position for the nova candidate is RA = 00h42m31.08s, Dec = +41d27'20.3"(J2000, accuracy of 0.3"), which is 149" west and 672" north of the core of M 31. We do not detect the object on a 4x60s stacked SLOTIS CCD image obtained on2010 December 5.213 UT (limiting R magnitude at the position of 19.0). There is no entry in VizieR/CDS for this object and no minor planet could be found on this position using the MPC/IAU Minor Planet Checker (see http://scully.harvard.edu/~cgi/CheckMP) . All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al.

  3. Quark nova model for fast radio bursts

    Science.gov (United States)

    Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid

    2016-05-01

    Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm‑3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (∼ 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.

  4. Modeling AGN outbursts from supermassive black hole binaries

    Directory of Open Access Journals (Sweden)

    Tanaka T.

    2012-12-01

    Full Text Available When galaxies merge to assemble more massive galaxies, their nuclear supermassive black holes (SMBHs should form bound binaries. As these interact with their stellar and gaseous environments, they will become increasingly compact, culminating in inspiral and coalescence through the emission of gravitational radiation. Because galaxy mergers and interactions are also thought to fuel star formation and nuclear black hole activity, it is plausible that such binaries would lie in gas-rich environments and power active galactic nuclei (AGN. The primary difference is that these binaries have gravitational potentials that vary – through their orbital motion as well as their orbital evolution – on humanly tractable timescales, and are thus excellent candidates to give rise to coherent AGN variability in the form of outbursts and recurrent transients. Although such electromagnetic signatures would be ideally observed concomitantly with the binary’s gravitational-wave signatures, they are also likely to be discovered serendipitously in wide-field, high-cadence surveys; some may even be confused for stellar tidal disruption events. I discuss several types of possible “smoking gun” AGN signatures caused by the peculiar geometry predicted for accretion disks around SMBH binaries.

  5. Echoes of multiple outbursts of Sagittarius A* revealed by Chandra

    CERN Document Server

    Clavel, Maïca; Goldwurm, A; Morris, M R; Ponti, G; Soldi, S; Trap, G

    2013-01-01

    The relatively rapid spatial and temporal variability of the X-ray radiation from some molecular clouds near the Galactic center shows that this emission component is due to the reflection of X-rays generated by a source that was luminous in the past, most likely the central supermassive black hole, Sagittarius A*. Studying the evolution of the molecular cloud reflection features is therefore a key element to reconstruct Sgr A*'s past activity. The aim of the present work is to study this emission on small angular scales in order to characterize the source outburst on short time scales. We use Chandra high-resolution data collected from 1999 to 2011 to study the most rapid variations detected so far, those of clouds between 5' and 20' from Sgr A* towards positive longitudes. Our systematic spectral-imaging analysis of the reflection emission, notably of the Fe Kalpha line at 6.4 keV and its associated 4-8 keV continuum, allows us to characterize the variations down to 15" angular scale and 1-year time scale. ...

  6. The Early ALMA View of the FU Ori Outburst System

    CERN Document Server

    Hales, A S; Dent, W R D; Andrews, S M; Eisner, J A; Cieza, L A

    2015-01-01

    We have obtained ALMA Band 7 observations of the FU Ori outburst system at 0.6"x0.5" resolution to measure the link between the inner disk instability and the outer disk through sub-mm continuum and molecular line observations. Our observations detect continuum emission which can be well modeled by two unresolved sources located at the position of each binary component. The interferometric observations recover the entire flux reported in previous single-dish studies, ruling out the presence of a large envelope. Assuming that the dust is optically thin, we derive disk dust masses of $2\\times 10^{-4}$M$_{\\odot}$ and $8\\times 10^{-5}$M$_{\\odot}$, for the north and south components respectively. We place limits on the disks' radii of $r<$45 AU. We report the detection of molecular emission from $^{12}$CO(3-2), HCO$^{+}$(4-3) and from HCN(4-3). The $^{12}$CO appears widespread across the two binary components, and is slightly more extended than the continuum emission. The denser gas tracer HCO$^{+}$ peaks close...

  7. Transient Fragments in Outbursting Comet 17P/Holmes

    CERN Document Server

    Stevenson, Rachel; Jewitt, David

    2010-01-01

    We present results from a wide-field imaging campaign at the Canada-France-Hawaii Telescope to study the spectacular outburst of comet 17P/Holmes in late 2007. Using image-processing techniques we probe inside the spherical dust coma and find sixteen fragments having both spatial distribution and kinematics consistent with isotropic ejection from the nucleus. Photometry of the fragments is inconsistent with scattering from monolithic, inert bodies. Instead, each detected fragment appears to be an active cometesimal producing its own dust coma. By scaling from the coma of the primary nucleus of 17P/Holmes, assumed to be 1.7 km in radius, we infer that the sixteen fragments have maximum effective radii between ~ 10 m and ~ 100 m on UT 2007 Nov. 6. The fragments subsequently fade at a common rate of ~ 0.2 mag/day, consistent with steady depletion of ices from these bodies in the heat of the Sun. Our characterization of the fragments supports the hypothesis that a large piece of material broke away from the nucle...

  8. Investigation of relationship between barometric pressure and coal and gas outburst events in underground coal mining

    Science.gov (United States)

    Yönet, Sinem; Esen, Olgun; Fişne, Abdullah

    2015-04-01

    Coal and gas outburst is a serious risk which occurs during the mine production. This accident results both ejection of high volumes of gas and high amount of coal into the mine production area, and death of mining workers for many years in Turkey. Outburst of gas, coal and rock can be defined as sudden release of coal and rock accompanied by large quantities of gas into the working face or other mine workings. It is a phenomena that influenced by geological structure such as folds, joints of rocks or coal seams, is also still investigated for many years. Zonguldak Coal Basin is the main part of the Upper Carboniferous bituminous coal basin of Turkey. Much of the bituminous coal mining has thus been concentrated in the Zonguldak Basin which is located on the Black Sea coast. The coal field has been disturbed by tectonic activity, first by Hercynian and later by Alpine orogenesis resulting in folding and faulting of strata. This formation has a complex structural geology which consists mostly fault zones, anticlinal and syncline strata and because of this a large amount of methane gases are adsorbed or accumulated in strata or in coal fractures, pores and micropores. There are 5 Collieries exists in Zonguldak Coalfield and coal and gas outbursts were occurred only in two collieries such as Karadon and Kozlu Mines. In addition at a number of 90 coal and gas outburst events were experienced in these collieries. Based on the analysis of data, oscillation at barometric pressure and temperature values at the location of Kozlu and Karadon Mines were seen when coal and gas outburst events were occurred. In this study, barometric pressure and temperature changes are investigated at Kozlu and Karadon Mines. Also the relationship between the variation at temperature with barometric pressure and coal and gas outbursts are evaluated. It can be understand that this investigation depends to field observations and macroscopic considerations and on the purpose of predicting the

  9. The role of spatial variability in coal seam parameters on gas outburst behaviour during coal mining

    Energy Technology Data Exchange (ETDEWEB)

    Wold, M.B.; Connell, L.D.; Choi, S.K. (CSIRO Petroleum, Ian Wark Laboratory, Bayview Avenue, Clayton, Victoria, 3168 Australia)

    2008-06-13

    Gas outburst is recognized as a potentially fatal hazard to be managed during the mining of gassy coal seams. Gas outbursts in Australian coal mines have been associated with the presence of geological structures in the coal and surrounding rocks, having a range of spatial scales from millimetres to metres. The contributing mechanisms are influenced by coal gas reservoir variables including gas composition, fluid pressure, desorption pressure and rate, porosity, intrinsic permeability and relative permeability. They are also influenced by geomechanical variables such as strength, in situ stress and mining-induced stress. The work described here concerns the influence of variability of permeability and strength on outburst behaviour. Key coal properties are characterised for a field site in an operational underground coal mine and then used in a series of hypothetical simulations of outburst initiation. At the field site an array of horizontal holes was cored in-seam. Well tests for permeability and stress were performed in the holes and recovered core was tested in the laboratory for permeability, strength and sorption properties. For permeability and strength sufficient numbers of measurements were obtained to describe these properties statistically assuming that the measurements are uncorrelated spatially. Analysis of the cumulative probability distributions of the field and laboratory permeability data shows a strong size effect that cannot be linearly up-scaled. Using Monte Carlo techniques, these statistical descriptions are used to generate realisations of property values across the model grid used in the simulation analyses. The stochastic model approach demonstrates that the variability of the permeability and strength fields can lead to both outburst and non-outburst outcomes from the same measured input data, depending on the corresponding spatial distribution of permeability and strength at the face. These results suggest the potential application of

  10. Events leading up to the 2015 June Outburst of V404 Cyg

    Science.gov (United States)

    Bernardini, F.; Russell, D. M.; Shaw, A. W.; Lewis, F.; Charles, P. A.; Koljonen, K. I. I.; Lasota, J. P.; Casares, J.

    2016-02-01

    On 2015 June 15 the burst alert telescope (BAT) on board Swift detected an X-ray outburst from the black hole (BH) transient V404 Cyg. We monitored V404 Cyg for the last 10 years with the 2-m Faulkes Telescope North in three optical bands (V, R, and i‧). We found that, one week prior to this outburst, the optical flux was 0.1-0.3 mag brighter than the quiescent orbital modulation, implying an optical precursor to the X-ray outburst. There is also a hint of a gradual optical decay (years) followed by a rise lasting two months prior to the outburst. We fortuitously obtained an optical spectrum of V404 Cyg 13 hr before the BAT trigger. This too was brighter than quiescence, and showed spectral lines typical of an accretion disk, with characteristic absorption features of the donor being much weaker. No He ii emission was detected, which would have been expected had the X-ray flux been substantially brightening. This, combined with the presence of intense Hα emission, about seven times the quiescent level, suggests that the disk entered the hot, outburst state before the X-ray outburst began. We propose that the outburst is produced by a viscous-thermal instability triggered close to the inner edge of a truncated disk. An X-ray delay of a week is consistent with the time needed to refill the inner region and hence move the inner edge of the disk inwards, allowing matter to reach the central BH, finally turning on the X-ray emission.

  11. Quantum emulation of classical dynamics

    OpenAIRE

    Margolus, Norman

    2011-01-01

    In statistical mechanics, it is well known that finite-state classical lattice models can be recast as quantum models, with distinct classical configurations identified with orthogonal basis states. This mapping makes classical statistical mechanics on a lattice a special case of quantum statistical mechanics, and classical combinatorial entropy a special case of quantum entropy. In a similar manner, finite-state classical dynamics can be recast as finite-energy quantum dynamics. This mapping...

  12. The man behind the curtain: X-rays drive the UV through NIR variability in the 2013 active galactic nucleus outburst in NGC 2617

    International Nuclear Information System (INIS)

    After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ∼70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over an order of magnitude followed by an increase of its optical/ultraviolet (UV) continuum flux by almost an order of magnitude. NGC 2617, classified as a Seyfert 1.8 galaxy in 2003, is now a Seyfert 1 due to the appearance of broad optical emission lines and a continuum blue bump. Such 'changing look active galactic nuclei (AGNs)' are rare and provide us with important insights about AGN physics. Based on the Hβ line width and the radius-luminosity relation, we estimate the mass of central black hole (BH) to be (4 ± 1) × 107 M ☉. When we cross-correlate the light curves, we find that the disk emission lags the X-rays, with the lag becoming longer as we move from the UV (2-3 days) to the NIR (6-9 days). Also, the NIR is more heavily temporally smoothed than the UV. This can largely be explained by a simple model of a thermally emitting thin disk around a BH of the estimated mass that is illuminated by the observed, variable X-ray fluxes.

  13. The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617

    CERN Document Server

    Shappee, B J; Grupe, D; Kochanek, C S; Stanek, K Z; De Rosa, G; Mathur, S; Zu, Y; Peterson, B M; Pogge, R W; Komossa, S; Im, M; Jencson, J; Holoien, T W-S; Basu, U; Beacom, J F; Szczygiel, D M; Brimacombe, J; Adams, S; Campillay, A; Choi, C; Contreras, C; Dietrich, M; Dubberley, M; Elphick, M; Foale, S; Giustini, M; Gonzalez, C; Hawkins, E; Howell, D A; Hsiao, E Y; Koss, M; Leighly, K M; Morrell, N; Mudd, D; Mullins, D; Nugent, J M; Parrent, J; Phillips, M M; Pojmanski, G; Rosing, W; Ross, R; Sand, D; Terndrup, D M; Valenti, S; Walker, Z; Yoon, Y

    2013-01-01

    After the All-Sky Automated Survey for SuperNovae (ASAS-SN) discovered a significant brightening of the inner region of NGC 2617, we began a ~70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over an order of magnitude followed by an increase of its optical/ultraviolet (UV) continuum flux by almost an order of magnitude. NGC 2617, classified as a Seyfert 1.8 galaxy in 2003, is now a Seyfert 1 due to the appearance of broad optical emission lines and a continuum blue bump. Such "changing look Active Galactic Nuclei (AGN)" are rare and provide us with important insights about AGN physics. Based on the Hbeta line width and the radius-luminosity relation, we estimate the mass of central black hole to be (4 +/- 1) x 10^7 M_sun. When we cross-correlate the light curves, we find that the disk emission lags the X-rays, with the lag becoming longer as we move...

  14. Randomness: quantum versus classical

    CERN Document Server

    Khrennikov, Andrei

    2015-01-01

    Recent tremendous development of quantum information theory led to a number of quantum technological projects, e.g., quantum random generators. This development stimulates a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is elaboration of a consistent and commonly accepted interpretation of quantum state. Closely related problem is clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. The second part of this review is devoted to the information interpretation of quantum mechanics (QM) in the spirit of Zeilinger and Brukner (and QBism of Fuchs et al.) and physics in general (e.g., Wheeler's "it from bit") as well as digital philosophy of Chaitin (with historical coupling to ideas of Leibnitz). Finally, w...

  15. Classical and statistical thermodynamics

    CERN Document Server

    Rizk, Hanna A

    2016-01-01

    This is a text book of thermodynamics for the student who seeks thorough training in science or engineering. Systematic and thorough treatment of the fundamental principles rather than presenting the large mass of facts has been stressed. The book includes some of the historical and humanistic background of thermodynamics, but without affecting the continuity of the analytical treatment. For a clearer and more profound understanding of thermodynamics this book is highly recommended. In this respect, the author believes that a sound grounding in classical thermodynamics is an essential prerequisite for the understanding of statistical thermodynamics. Such a book comprising the two wide branches of thermodynamics is in fact unprecedented. Being a written work dealing systematically with the two main branches of thermodynamics, namely classical thermodynamics and statistical thermodynamics, together with some important indexes under only one cover, this treatise is so eminently useful.

  16. Computation in Classical Mechanics

    CERN Document Server

    Timberlake, Todd

    2007-01-01

    There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss the ways we have used computation in our classical mechanics courses, focusing on how computational work can improve students' understanding of physics as well as their computational skills. We present examples of computational problems that serve these two purposes. In addition, we provide information about resources for instructors who would like to include computation in their courses.

  17. The classic project

    International Nuclear Information System (INIS)

    Exchange of data and algorithms among accelerator physics programs is difficult because of unnecessary differences in input formats and internal data structures. To alleviate these problems a C++ class library called CLASSIC (Class Library for Accelerator System Simulation and Control) is being developed with the goal to provide standard building blocks for computer programs used in accelerator design. It includes modules for building accelerator lattice structures in computer memory using a standard input language, a graphical user interface, or a programmed algorithm. It also provides simulation algorithms. These can easily be replaced by modules which communicate with the control system of the accelerator. Exchange of both data and algorithm between different programs using the CLASSIC library should present no difficulty

  18. Injuries in classical ballet

    Directory of Open Access Journals (Sweden)

    Adriana Coutinho de Azevedo Guimarães

    2008-06-01

    Full Text Available This study aimed to elucidate what injuries are most likely to occur due to classical ballet practice. The research used national and international bibliography. The bibliography analysis indicated that technical and esthetical demands lead to a practice of non-anatomical movements, causing the ballet dancer to suffer from a number of associated lesions. Most of the injuries are caused by technical mistakes and wrong training. Troubles in children are usually due to trying to force external rotation at hip level and to undue use of point ballet slippers. The commonest lesions are in feet and ankles, followed by knees and hips. The rarest ones are in the upper limbs. These injuries are caused by exercise excess, by repetitions always in the same side and by wrong and early use of point slippers. The study reached the conclusion that incorrect application of classical ballet technique predisposes the dancers to characteristic injuries.

  19. Classical Diophantine equations

    CERN Document Server

    1993-01-01

    The author had initiated a revision and translation of "Classical Diophantine Equations" prior to his death. Given the rapid advances in transcendence theory and diophantine approximation over recent years, one might fear that the present work, originally published in Russian in 1982, is mostly superseded. That is not so. A certain amount of updating had been prepared by the author himself before his untimely death. Some further revision was prepared by close colleagues. The first seven chapters provide a detailed, virtually exhaustive, discussion of the theory of lower bounds for linear forms in the logarithms of algebraic numbers and its applications to obtaining upper bounds for solutions to the eponymous classical diophantine equations. The detail may seem stark--- the author fears that the reader may react much as does the tourist on first seeing the centre Pompidou; notwithstanding that, Sprind zuk maintainsa pleasant and chatty approach, full of wise and interesting remarks. His emphases well warrant, ...

  20. Are superparamagnetic spins classical?

    OpenAIRE

    Garanin, D. A.

    2008-01-01

    Effective giant spins of magnetic nanoparticles are considered classically in the conventional theory of superparamagnetism based on the Landau-Lifshitz-Langevin equation. However, microscopic calculations for a large spin with uniaxial anisotropy, coupled to the lattice via the simplest generic mechanism, show that the results of the conventional theory are not reproduced in the limit S ->\\infty. In particular, the prefactor Gamma_0 in the Arrhenius escape rate over the barrier Gamma =Gamma_...