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Sample records for recurrent novae progenitors

  1. Recurrent novae

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi

    1993-01-01

    Recurrent novae seem to be a rather inhomogeneous group: T CrB is a binary with a M III companion; U Sco probably has a late dwarf as companion. Three are fast novae; two are slow novae. Some of them appear to have normal chemical composition; others may present He and CNO excess. Some present a mass-loss that is lower by two orders of magnitude than classical novae. However, our sample is too small for saying whether there are several classes of recurrent novae, which may be related to the various classes of classical novae, or whether the low mass-loss is a general property of the class or just a peculiarity of one member of the larger class of classical novae and recurrent novae.

  2. Lesson Learned from (some) Recurrent Novae

    NASA Astrophysics Data System (ADS)

    Mason, E.; Walter, F. M.

    2014-12-01

    In this talk we present early decline and nebular spectra of the recurrent novae YY Dor and nova LMC 2009. These and a few other recurrent novae of the same type, share similar spectral characteristics and evolution. We will discuss those common features critically suggesting same white dwarf progenitor and post outburst phases for all of them.

  3. RECURRENT NOVAE IN M31

    SciTech Connect

    Shafter, A. W.; Henze, M.; Rector, T. A.; Schweizer, F.; Hornoch, K.; Orio, M.; Pietsch, W.; Darnley, M. J.; Williams, S. C.; Bode, M. F.; Bryan, J.

    2015-02-01

    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.

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

    SciTech Connect

    Bode, M. F.; Darnley, M. J.; Hilton, T.; Shafter, A. W.; Page, K. L.; Smirnova, O.; Anupama, G. C.

    2009-11-01

    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 Halpha approx = 4500 km s{sup -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 {sub WD} approx> 1.3 M {sub 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.

  5. Classical novae and recurrent novae: General properties

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi; Duerbeck, Hilmar W.

    1993-01-01

    We describe the observable characteristics of classical novae and recurrent novae obtained by different techniques (photometry, spectroscopy, and imaging) in all the available spectral ranges. We consider the three stages in the life of a nova: quiescence (pre- and post-outburst), outburst, final decline and nebular phase. We describe the photometric properties during the quiescent phase. We describe the photometric properties during outburst, the classification according the rate of decline (magnitudes per day), which permits us to define very fast, fast, intermediate, slow, and very slow novae and the correlation between luminosity and speed class. We report the scanty data on the spectra of the few known prenovae and those on the spectra of old novae and those of dwarf novae and nova-like, which, however, are almost undistinguishable. We describe the typical spectra appearing from the beginning of the outburst, just before maximum, up to the nebular phase and the correlation between spectral type at maximum, expansional velocity, and speed class of the nova. We report the existing infrared observations, which permit us to explain some of the characteristics of the outburst light curve, and give evidence of the formation of a dust shell in slow and intermediate novae (with the important exception of the very slow nova HR Del 1967) and its absence or quasi-absence in fast novae. The ultraviolet and X-ray observations are described. The X ray observations of novae, mainly from the two satellites EINSTEIN and EXOSAT, are reported. Observations of the final decline and of the envelopes appearing several months after outburst are also reported.

  6. Identification of Recurrent Novae in M31

    NASA Astrophysics Data System (ADS)

    Shafter, Allen W.; Rector, T. A.; Schweizer, F.; Bryan, J.

    2014-01-01

    Over roughly the past century a total of more than 900 optical transient events have been recorded in M31, the vast majority of which are believed to represent eruptions of classical novae. The impressive dataset of nova positions put together by Pietsch (http://www.mpe.mpg.de m31novae/opt/m31/) provides the opportunity to search for multiple nova outbursts from the same progenitor system, and thus to characterize the population of recurrent novae (RNe) in M31. In order to identify RNe candidates, we have searched for spatial near coincidences among the 945 recorded novae given in the Pietsch catalog through the end of August 2013. Given that the positions of many of the early novae are quite uncertain, we have set our initial screen to include nova pairs with nominal separations less than or equal to 6 arcsec. We have identified a total of 102 novae that pass this coarse screen. Of these, 78 novae form 39 pairs, 15 form five triples, four novae are part of a quad, and five novae form a quint. As demonstrated by Shafter, Rice and Daub (2009, presented at the "Wild Stars in the Old West II" conference, mintaka.sdsu.edu/faculty/shafter/extragalactic_novae/RNePoster4.pdf), the majority of the 102 novae surviving our initial screen are expected to be associated with chance positional near coincidences (especially near the nucleus), and are not RNe. To decide which candidates are indeed RNe, we have undertaken a study to locate the original discovery plates, CCD images or published finding charts, and to perform the necessary astrometry to identify which of our candidate RNe are chance positional coincidences, and which are RNe. For each candidate, we estimate the probability that the object is a chance positional coincidence as in Shafter et al. (2009). To date, we have been successful in identifying finding charts or original images for most of the candidates, and have found a total of 23 nova outbursts in M31 associated with 10 systems that are almost certainly RNe.

  7. Identifying and quantifying recurrent novae masquerading as classical novae

    SciTech Connect

    Pagnotta, Ashley; Schaefer, Bradley E.

    2014-06-20

    Recurrent novae (RNe) are cataclysmic variables with two or more nova eruptions within a century. Classical novae (CNe) are similar systems with only one such eruption. Many of the so-called CNe are actually RNe for which only one eruption has been discovered. Since RNe are candidate Type Ia supernova progenitors, it is important to know whether there are enough in our Galaxy to provide the supernova rate, and therefore to know how many RNe are masquerading as CNe. To quantify this, we collected all available information on the light curves and spectra of a Galactic, time-limited sample of 237 CNe and the 10 known RNe, as well as exhaustive discovery efficiency records. We recognize RNe as having (1) outburst amplitude smaller than 14.5 – 4.5 × log (t {sub 3}), (2) orbital period >0.6 days, (3) infrared colors of J – H > 0.7 mag and H – K > 0.1 mag, (4) FWHM of Hα > 2000 km s{sup –1}, (5) high excitation lines, such as Fe X or He II near peak, (6) eruption light curves with a plateau, and (7) white dwarf mass greater than 1.2 M {sub ☉}. Using these criteria, we identify V1721 Aql, DE Cir, CP Cru, KT Eri, V838 Her, V2672 Oph, V4160 Sgr, V4643 Sgr, V4739 Sgr, and V477 Sct as strong RN candidates. We evaluate the RN fraction among the known CNe using three methods to get 24% ± 4%, 12% ± 3%, and 35% ± 3%. With roughly a quarter of the 394 known Galactic novae actually being RNe, there should be approximately a hundred such systems masquerading as CNe.

  8. Shortest recurrence periods of novae

    SciTech Connect

    Kato, Mariko; Saio, Hideyuki; Hachisu, Izumi; Nomoto, Ken'ichi

    2014-10-01

    Stimulated by the recent discovery of the 1 yr recurrence period nova M31N 2008-12a, we examined the shortest recurrence periods of hydrogen shell flashes on mass-accreting white dwarfs (WDs). We discuss the mechanism that yields a finite minimum recurrence period for a given WD mass. Calculating the unstable flashes for various WD masses and mass accretion rates, we identified a shortest recurrence period of about two months for a non-rotating 1.38 M {sub ☉} WD with a mass accretion rate of 3.6 × 10{sup –7} M {sub ☉} yr{sup –1}. A 1 yr recurrence period is realized for very massive (≳ 1.3 M {sub ☉}) WDs with very high accretion rates (≳ 1.5 × 10{sup –7} M {sub ☉} yr{sup –1}). We revised our stability limit of hydrogen shell burning, which will be useful for binary evolution calculations toward Type Ia supernovae.

  9. ON THE PROGENITORS OF LOCAL GROUP NOVAE. I. THE M31 CATALOG

    SciTech Connect

    Williams, S. C.; Darnley, M. J.; Bode, M. F.; Keen, A.; Shafter, A. W.

    2014-07-01

    We report the results of a survey of M31 novae in quiescence. This is the first catalog of extragalactic systems in quiescence to be published, and contains data for 38 spectroscopically confirmed novae from 2006 to 2012. We used Liverpool Telescope images of each nova during eruption to define an accurate position for each system. These positions were then matched to archival Hubble Space Telescope (HST) images and we performed photometry on any resolved objects that were coincident with the eruption positions. The survey aimed to detect quiescent systems with red giant secondaries, as only these, along with a few systems with bright sub-giant secondaries, will be resolvable in the HST images. There are only a few confirmed examples of such red giant novae in our Galaxy, the majority of which are recurrent novae. However, we find that a relatively high percentage of the nova eruptions in M31 may occur in systems containing red giant secondaries. Of the 38 systems in this catalog, 11 have a progenitor candidate whose probability of being a coincidental alignment is less than 5%. We show that at the 3σ limit, up to only 2 of these 11 systems may be due to chance alignments, leading to an estimate of the M31 nova population with evolved secondaries of up to 24%, compared to the ∼3% seen Galactically. Such an elevated proportion of nova systems with evolved secondaries may imply the presence of a much larger population of recurrent novae than previously thought. This would have considerable impact, particularly with regards to their potential as Type Ia supernova progenitors. Additionally, for several novae, serendipitous HST images had been taken when the nova was still fading; this allowed us to produce light curves that go fainter than is usually achievable for most extragalactic systems. Finally, as this survey is astrometric in nature, we also update the position of each nova in the catalog.

  10. Models of classical and recurrent novae

    NASA Technical Reports Server (NTRS)

    Friedjung, Michael; Duerbeck, Hilmar W.

    1993-01-01

    The behavior of novae may be divided roughly into two separate stages: quiescence and outburst. However, at closer inspection, both stages cannot be separated. It should be attempted to explain features in both stages with a similar model. Various simple models to explain the observed light and spectral observations during post optical maximum activity are conceivable. In instantaneous ejection models, all or nearly all material is ejected in a time that is short compared with the duration of post optical maximum activity. Instantaneous ejection type 1 models are those where the ejected material is in a fairly thin shell, the thickness of which remains small. In the instantaneous ejection type 2 model ('Hubble Flow'), a thick envelope is ejected instantaneously. This envelope remains thick as different parts have different velocities. Continued ejection models emphasize the importance of winds from the nova after optical maximum. Ejection is supposed to occur from one of the components of the central binary, and one can imagine a general swelling of one of the components, so that something resembling a normal, almost stationary, stellar photosphere is observed after optical maximum. The observed characteristics of recurrent novae in general are rather different from those of classical novae, thus, models for these stars need not be the same.

  11. On the Progenitors of Local Group Novae. II. The Red Giant Nova Rate of M31

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Darnley, M. J.; Bode, M. F.; Shafter, A. W.

    2016-02-01

    In our preceding paper, Liverpool Telescope data of M31 novae in eruption were used to facilitate a search for their progenitor systems within archival Hubble Space Telescope data, with the aim of detecting systems with red giant secondaries (RG-novae) or luminous accretion disks. From an input catalog of 38 spectroscopically confirmed novae with archival quiescent observations, likely progenitors were recovered for 11 systems. Here we present the results of the subsequent statistical analysis of the original survey, including possible biases associated with the survey and the M31 nova population in general. As part of this analysis, we examine the distribution of optical decline times (t2) of M31 novae, how the likely bulge and disk nova distributions compare, and how the M31 t2 distribution compares to that of the Milky Way. Using a detailed Monte Carlo simulation, we determine that {30}-10+13% of all M31 nova eruptions can be attributed to RG-nova systems, and at the 99% confidence level, \\gt 10% of all M31 novae are RG-novae. This is the first estimate of a RG-nova rate of an entire galaxy. Our results also imply that RG-novae in M31 are more likely to be associated with the M31 disk population than the bulge; indeed, the results are consistent with all RG-novae residing in the disk. If this result is confirmed in other galaxies, it suggests that any Type Ia supernovae that originate from RG-nova systems are more likely to be associated with younger populations and may be rare in old stellar populations, such as early-type galaxies.

  12. COMPREHENSIVE PHOTOMETRIC HISTORIES OF ALL KNOWN GALACTIC RECURRENT NOVAE

    SciTech Connect

    Schaefer, Bradley E.

    2010-04-01

    I collect virtually all photometry of the 10 known galactic recurrent novae (RNe) and their 37 known eruptions. This consists of my modern measures of nearly all archival plates (providing the only data for half of 37 known eruptions), my own 10,000 CCD magnitudes from 1987 to present (providing virtually all of the magnitudes in quiescence for seven RNe), over 140,000 visual magnitude estimates recorded by amateur astronomers (who discovered half the known eruptions), and the small scattering of magnitudes from all the literature. From this, I produce various uniform products: (1) BVRIJHK comparison star magnitudes and BV comparison star sequences to cover the entire range of eruption; (2) complete light curves for all eruptions; (3) best-fit B and V light curve templates; (4) orbital periods for all but one RN; (5) exhaustive searches for all missed eruptions; (6) measured discovery efficiencies since 1890; (7) true recurrence time scales; (8) predicted next eruption dates; (9) variations on time scales of minutes, hours, days, months, years, decades, and century; (10) uniform distances and extinctions to all RNe; (11) BV colors at peak and UBVRIJHK colors at minimum, all with extinction corrections; and (12) the spectral energy distributions over UBVRIJHK. Highlights of this work include the discoveries of one new RN, six previously unknown eruptions, and the orbital periods for half the RNe. The goal of this work is to provide uniform demographics for answering questions like the 'What is the death rate of RNe in our Galaxy?' and 'Are the white dwarfs gaining or losing mass over each eruption cycle?.' An important use of this work is for the question of whether RNe can be the progenitors of Type Ia supernovae.

  13. Ultraviolet spectroscopy of the recurrent nova U Scorpii during outburst

    NASA Technical Reports Server (NTRS)

    Williams, R. E.; Sparks, W. M.; Gallagher, J. S.; Ney, E. P.; Starrfield, S. G.; Truran, J. W.

    1981-01-01

    Observations of the recurrent nova U Sco during the 1979 outburst are presented, and the spectral evolution is found to differ from that of other recurrent novas. Spectra are dominated by emission lines, and the strong forbidden-line emission characteristic is conspicuously absent. A method to determine masses of nova shells is outlined, and an analysis of the emission lines shows an enrichment in N relative to C and O, and that the nova ejecta are rich in He relative to H. Optical spectra of U Sco obtained following its return to quiescence show predominantly He II emission lines, which suggests an enrichment of the preoutburst gas in He, and thus the presence of a highly evolved companion.

  14. Outburst of the recurrent nova V745 Sco

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2014-02-01

    The outburst of the recurrent nova V745 Sco (Nova Sco 1937) by Rod Stubbings (Tetoora Road, VIC, Australia) at visual magnitude 9.0 on 2014 February 6.694 UT is reported. This recurrent nova is fading quickly. Follow-up observations of all types (visual, CCD, DSLR) are strongly encouraged, as is spectroscopy; fast time-series of this nova may be useful to detect possible flaring activity as was observed during the outburst of U Scorpii in 2010. Coincident time-series by multiple observers would be most useful for such a study, with a V-filter being preferred. Observations reported to the AAVSO International Database show V745 Sco at visual mag. 10.2 on 2014 Feb. 07.85833 UT (A. Pearce, Nedlands, W. Australia). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. Previous outbursts occurred in 1937 and 1989. The 1937 outburst was detected in 1958 (in decline at magnitude 11.0 on 1937 May 11.1 UT; outburst had occurred within the previous 19 days) by Lukas Plaut on plates taken by Hendrik van Gent at the Leiden Observatory; the object was announced as Nova Sco 1937 and later assigned the GCVS name V745 Sco. The 1989 outburst was detected on 1989 August 1.55 UT by Mati Morel (MMAT, Thornton, NSW, Australia) at visual magnitude 10.4 and in decline. Dr. Bradley Schaefer (Louisiana State University) reports (2010ApJS..187..275S) in his comprehensive analysis of the 10 known galactic recurrent novae (including V745 Sco) that the median interval between recurrent novae outbursts is 24 years. The interval since the 1989 outburst of V745 Sco is 24.10 years. See the Alert Notice for additional visual and multicolor photometry and for more details.

  15. One eruption every (half?) year - A remarkable recurrent nova in M31

    NASA Astrophysics Data System (ADS)

    Henze, Martin

    2016-07-01

    Recurrent Novae (RN) are those for which more than one eruption has been observed. Only ten RN are known in our Galaxy, while 17 such objects have been observed in the neighbouring Andromeda galaxy (M31). The object M31N 2008-12a stands out as a unique RN in M31 since it showed eight observed eruptions in the last eight years and has a suspected recurrence time between successive eruptions of only six months. Its eruption frequency is unparalleled: the recurrence time is at least an order of magnitude shorter than for the fastest Galactic RN, U Sco. Theoretical models predict M31N 2008-12a to have a WD mass close to the Chandrasekhar limit and a high accretion rate, making it the most promising candidate for a single-degenerate type Ia supernova progenitor known to date. For the first time, we can conduct statistical studies of repeated eruptions in an individual nova. I will present new results from the recent 2015 eruption and the early 2016 monitoring campaign. I will discuss these results in the context of the known eruption history and provide an outlook towards future observing plans and the ultimate fate of this remarkable nova.

  16. Pan-chromatic Observations of the Recurrent Nova LMC 2009a (LMC 1971b)

    NASA Astrophysics Data System (ADS)

    Bode, M. F.; Darnley, M. J.; 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.

    2016-02-01

    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 (UV) and X-ray observations from 9 days to almost 1 year post-outburst. We find MV = -8.4 ± 0.8r ± 0.7s and expansion velocities between 1000 and 4000 km s-1. Coronal line emission before day 9 indicates shocks in the ejecta. Strengthening of He iiλ4686 preceded the emergence of the super-soft source (SSS) in X-rays at ˜63-70 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 most likely a sub-giant feeding a luminous accretion disk. Properties of the SSS infer a white dwarf (WD) mass 1.1 M⊙ ≲ MWD ≲ 1.3 M⊙. If the accretion occurs at a constant rate, {\\dot{M}}{{acc}}≃ {3.6}-2.5+4.7× {10}-7 {M}⊙ yr-1 is needed, consistent with nova models for an inter-eruption interval of 38 years, low outburst amplitude, progenitor position in the color-magnitude diagram, and spectral energy distribution at quiescence. We note striking similarities between LMC 2009a and the Galactic nova KT Eri, suggesting that KT Eri is a candidate RN.

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

    SciTech Connect

    Banerjee, D. P. K.; Joshi, Vishal; Venkataraman, V.; Ashok, N. M.; Raj, A.; Marion, G. H.; Hsiao, E. Y.

    2014-04-10

    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{sup –1} plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 10{sup 8} 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.

  18. Searches for the progenitor of Nova ASASSN-16ig

    NASA Astrophysics Data System (ADS)

    Saito, R. K.; Minniti, D.; Catelan, M.; Angeloni, R.; Gutierrez, L. A.

    2016-08-01

    Stanek et al. (ATel #9343) recently reported the discovery of a likely classical nova about 4.2 degrees away from the Galactic center. Nova ASASSN-16ig is located at coordinates RA,DEC(J2000)= 18:01:07.735,-26:31:42.01, corresponding to l,b=3.813,-1.741, within the area covered by the VVV Survey (vvvsurvey.org; Minniti et al. 2010, New Astronomy, 15, 433).

  19. THE NOVA SHELL AND EVOLUTION OF THE RECURRENT NOVA T PYXIDIS

    SciTech Connect

    Schaefer, Bradley E.; Pagnotta, Ashley; Shara, Michael M.

    2010-01-01

    T Pyxidis (T Pyx) is the prototypical recurrent nova (RN), with five eruptions from 1890 to 1967 and a mysterious nova shell. We report new observations of the nova shell with the Hubble Space Telescope (HST) in the year 2007, which provides a long time baseline to compare with HST images from 1994 and 1995. We find that the knots in the nova shell are expanding with velocities ranging from roughly 500 km s{sup -1} to 715 km s{sup -1}, assuming a distance of 3500 pc. The fractional expansion of the knots is constant, which implies no significant deceleration of the knots, which must have been ejected by an eruption close to the year 1866. We see knots that have turned on after 1995; this shows that the knots are powered by shocks from the collision of the '1866' ejecta with fast ejecta from later RN eruptions. We derive that the '1866' ejecta has a total mass of approx10{sup -4.5} M {sub sun}, which with the low ejection velocity shows that the '1866' event was an ordinary nova eruption, not an RN eruption. This also implies that the accretion rate before the ordinary nova event must have been low (around the 4 x 10{sup -11} M{sub sun} yr{sup -1} expected for gravitational radiation alone), and that the matter accumulated on the surface of the white dwarf for approx750,000 years. The current accretion rate (>10{sup -8} M{sub sun} yr{sup -1}) is approx1000x higher than expected for a system below the period gap, with the plausible reason being that the '1866' event started a continuing supersoft source that drives the accretion. The accretion rate has been declining since before the 1890 eruption, with the current rate being only 3% of its earlier value. The decline in the observed accretion rate shows that the supersoft source is not self-sustaining; we calculate that the accretion in T Pyx will effectively stop in upcoming decades. With this, T Pyx will enter a state of hibernation lasting for an estimated 2,600,000 years before gravitational radiation brings the

  20. Insights into the evolution of symbiotic recurrent novae from radio synchrotron emission: V745 Scorpii and RS Ophiuchi

    NASA Astrophysics Data System (ADS)

    Kantharia, N. G.; Dutta, Prasun; Roy, Nirupam; Anupama, G. C.; Ishwara-Chandra, C. H.; Chitale, A.; Prabhu, T. P.; Banerjee, D. P. K.; Ashok, N. M.

    2016-02-01

    We present observations at 610 and 235 MHz using the Giant Metrewave Radio Telescope (GMRT) of the recurrent nova V745 Scorpii which recorded its last outburst on 2014 February 6. This is the second symbiotic recurrent nova whose light curve at low frequencies has been followed in detail, the first being RS Ophiuchi in 2006. We fitted the 610 MHz light curve by a model of synchrotron emission from an expanding shell being modified by radiative transfer effects due to local absorbing gas consisting of a uniformly distributed and a clumpy component. Using our model parameters, we find that the emission at 235 MHz peaked around day 35 which is consistent with our GMRT observations. The two main results of our study are (1) The radio emission at a given frequency is visible sooner after the outburst in successive outbursts of both V745 Scorpii and RS Ophiuchi. The earlier detection of radio emission is interpreted to be caused by decreasing foreground densities. (2) The clumpy material, if exists, is close to the white dwarf and can be interpreted as being due to the material from the hot accretion disc. The uniform density gas is widespread and attributed to the winds blown by the white dwarf. We present implications of these results on the evolution of both novae. Such studies along with theoretical understanding have the potential of resolving several outstanding issues such as why all recurrent novae are not detectable in synchrotron radio and whether recurrent novae are progenitor systems of Type 1a supernova.

  1. Constraining the role of novae as progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Soraisam, Monika D.; Gilfanov, Marat

    2015-11-01

    Context. With the progenitors of type Ia supernovae (SNe Ia) still eluding direct detections, various types of accreting white dwarfs (WDs) have been proposed as prospective candidates. One of the possibilities are WDs undergoing unstable nuclear burning on their surfaces. Although observations and theoretical modeling of classical novae generally suggest that more material is ejected during the explosion than is accreted, there is growing evidence that in certain accretion regimes of novae, appreciable mass accumulation by the WD in the course of unstable nuclear burning may be possible. Aims: We propose that statistics of novae in nearby galaxies may be a powerful tool to determine the role these systems play in producing SNe Ia. Methods: We used multicycle nova evolutionary models to compute the number and temporal distribution of novae that would be produced by a typical SN Ia progenitor before it reached the Chandrasekhar mass limit (Mch) and exploded, assuming that it experienced unstable nuclear burning during its entire accretion history. We then used the observed nova rate in M 31 to constrain the maximal contribution of the nova channel to the SN Ia rate in this galaxy. Results: The M 31 nova rate measured by the POINT-AGAPE survey is ≈ 65 yr-1. Assuming that all these novae will reach Mch, we estimate the maximal SN Ia rate novae may produce, which is ≲0.1-0.5 × 10-3 yr-1. This constrains the overall contribution of the nova channel to the SN Ia rate at ≲ 2-7%. However, if all POINT-AGAPE novae do eventually reach Mch, a significant population of fast novae (t2 ≲ 10 days) originating from the most massive WDs is expected, with a rate of ~200-300 yr-1, which is significantly higher than currently observed. We point out that statistics of such fast novae can provide powerful diagnostics of the contribution of the nova channel to the final stage of mass accumulation by the single-degenerate (SD) SN Ia progenitors. To explore the prospects of their

  2. Photometric evolution, orbital modulation and progenitor of Nova Mon 2012

    NASA Astrophysics Data System (ADS)

    Munari, U.; Dallaporta, S.; Castellani, F.; Valisa, P.; Frigo, A.; Chomiuk, L.; Ribeiro, V. A. R. M.

    2013-10-01

    We present and discuss accurate and densely mapped BVRCIC light curves of the neon Nova Mon 2012, supplemented by the evolution in Stromgren b and y bands and in the integrated flux of relevant emission lines. Our monitoring started with the optical discovery of the nova (50 days past the first detection in gamma-rays by Fermi-LAT) and extend to day +270, well past the end of the super-soft phase in X-rays. The nova was discovered during the nebular decline, well past t3 and the transition to optically thin ejecta. It displayed very smoothly evolving light curves. A bifurcation between y and V light curves took place at the start of the super-soft X-ray source (SSS) phase, and a knee developed towards the end of the SSS phase. The apparent magnitude of the nova at the unobserved optical maximum is constrained to +3 ≤ V ≤ 4.5. The appearance, grow in amplitude and then demise of a 0.29585 (±0.00002) days orbital modulation of the optical brightness was followed along the nova evolution. The observed modulation, identical in phase and period with the analogue seen in the X-ray and satellite ultraviolet, has a near-sinusoidal shape and a weak secondary minimum at phase 0.5. We favour an interpretation in terms of super-imposed ellipsoidal distortion of the Roche lobe filling companion and irradiation of its side facing the WD. Similar light curves are typical of symbiotic stars where a Roche lobe filling giant is irradiated by a very hot WD. Given the high orbital inclination, mutual occultation between the donor star and the accretion disc could contribute to the observed modulation. The optical+infrared spectral energy distribution of Nova Mon 2012 during the quiescence preceding outburst is nicely fitted by an early K-type main-sequence star (˜K3V) at 1.5 kpc distance, reddened by E(B - V) = 0.38, with a WD companion and an accretion disc contributing to the observed blue excess and moderate Hα emission. A typical early K-type main-sequence star with a mass

  3. A remarkable recurrent nova in M31: Discovery and optical/UV observations of the predicted 2014 eruption

    NASA Astrophysics Data System (ADS)

    Darnley, M. J.; Henze, M.; Steele, I. A.; Bode, M. F.; Ribeiro, V. A. R. M.; Rodríguez-Gil, P.; Shafter, A. W.; Williams, S. C.; Baer, D.; Hachisu, I.; Hernanz, M.; Hornoch, K.; Hounsell, R.; Kato, M.; Kiyota, S.; Kučáková, H.; Maehara, H.; Ness, J.-U.; Piascik, A. S.; Sala, G.; Skillen, I.; Smith, R. J.; Wolf, M.

    2015-08-01

    The Andromeda Galaxy recurrent nova M31N 2008-12a had been caught in eruption eight times. The inter-eruption period of M31N 2008-12a is ~1 yr, making it the most rapidly recurring system known, and a strong single-degenerate Type Ia supernova progenitor candidate. Following the 2013 eruption, a campaign was initiated to detect the predicted 2014 eruption and to then perform high cadence optical photometric and spectroscopic monitoring using ground-based telescopes, along with rapid UV and X-ray follow-up with the Swift satellite. Here we report the results of a high cadence multi-colour optical monitoring campaign, the spectroscopic evolution, and the UV photometry. We also discuss tantalising evidence of a potentially related, vastly-extended, nebulosity. The 2014 eruption was discovered, before optical maximum, on October 2, 2014. We find that the optical properties of M31N 2008-12a evolve faster than all Galactic recurrent novae known, and all its eruptions show remarkable similarity both photometrically and spectroscopically. Optical spectra were obtained as early as 0.26 days post maximum, and again confirm the nova nature of the eruption. A significant deceleration of the inferred ejecta expansion velocity is observed which may be caused by interaction of the ejecta with surrounding material,possibly a red giant wind. We find a low ejected mass and low ejection velocity, which are consistent with high mass-accretion rate, high mass white dwarf, and short recurrence time models of novae. We encourage additional observations, especially around the predicted time of the next eruption, towards the end of 2015. Tables 6-8 are available in electronic form at http://www.aanda.orgPhotometry is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A45

  4. PTF 11kx: a type Ia supernova with a symbiotic nova progenitor.

    PubMed

    Dilday, B; Howell, D A; Cenko, S B; Silverman, J M; Nugent, P E; Sullivan, M; Ben-Ami, S; Bildsten, L; Bolte, M; Endl, M; Filippenko, A V; Gnat, O; Horesh, A; Hsiao, E; Kasliwal, M M; Kirkman, D; Maguire, K; Marcy, G W; Moore, K; Pan, Y; Parrent, J T; Podsiadlowski, P; Quimby, R M; Sternberg, A; Suzuki, N; Tytler, D R; Xu, D; Bloom, J S; Gal-Yam, A; Hook, I M; Kulkarni, S R; Law, N M; Ofek, E O; Polishook, D; Poznanski, D

    2012-08-24

    There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi. PMID:22923575

  5. PTF 11kx: a type Ia supernova with a symbiotic nova progenitor.

    PubMed

    Dilday, B; Howell, D A; Cenko, S B; Silverman, J M; Nugent, P E; Sullivan, M; Ben-Ami, S; Bildsten, L; Bolte, M; Endl, M; Filippenko, A V; Gnat, O; Horesh, A; Hsiao, E; Kasliwal, M M; Kirkman, D; Maguire, K; Marcy, G W; Moore, K; Pan, Y; Parrent, J T; Podsiadlowski, P; Quimby, R M; Sternberg, A; Suzuki, N; Tytler, D R; Xu, D; Bloom, J S; Gal-Yam, A; Hook, I M; Kulkarni, S R; Law, N M; Ofek, E O; Polishook, D; Poznanski, D

    2012-08-24

    There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.

  6. Collimation and Asymmetry of the Hot Blast Wave from the Recurrent Nova V745 Sco

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy J.; Delgado, Laura; Laming, J. Martin; Starrfield, Sumner; Kashyap, Vinay; Orlando, Salvatore; Page, Kim L.; Hernanz, M.; Ness, J.-U.; Gehrz, R. D.; van Rossum, Daan; Woodward, Charles E.

    2016-07-01

    The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was observed on February 22 and 23 by the Chandra X-ray Observatory Transmission Grating Spectrometers. By that time the supersoft source phase had already ended, and Chandra spectra are consistent with emission from a hot, shock-heated circumstellar medium with temperatures exceeding 107 K. X-ray line profiles are more sharply peaked than expected for a spherically symmetric blast wave, with a full width at zero intensity of approximately 2400 km s-1, an FWHM of 1200 ± 30 km s-1, and an average net blueshift of 165 ± 10 km s-1. The red wings of lines are increasingly absorbed toward longer wavelengths by material within the remnant. We conclude that the blast wave was sculpted by an aspherical circumstellar medium in which an equatorial density enhancement plays a role, as in earlier symbiotic nova explosions. Expansion of the dominant X-ray-emitting material is aligned close to the plane of the sky and is most consistent with an orbit seen close to face-on. Comparison of an analytical blast wave model with the X-ray spectra, Swift observations, and near-infrared line widths indicates that the explosion energy was approximately 1043 erg and confirms an ejected mass of approximately 10-7 M ⊙. The total mass lost is an order of magnitude lower than the accreted mass required to have initiated the explosion, indicating that the white dwarf is gaining mass and is a Type Ia supernova progenitor candidate.

  7. Collimation and Asymmetry of the Hot Blast Wave from the Recurrent Nova V745 Sco

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy J.; Delgado, Laura; Laming, J. Martin; Starrfield, Sumner; Kashyap, Vinay; Orlando, Salvatore; Page, Kim L.; Hernanz, M.; Ness, J.-U.; Gehrz, R. D.; van Rossum, Daan; Woodward, Charles E.

    2016-07-01

    The recurrent symbiotic nova V745 Sco exploded on 2014 February 6 and was observed on February 22 and 23 by the Chandra X-ray Observatory Transmission Grating Spectrometers. By that time the supersoft source phase had already ended, and Chandra spectra are consistent with emission from a hot, shock-heated circumstellar medium with temperatures exceeding 107 K. X-ray line profiles are more sharply peaked than expected for a spherically symmetric blast wave, with a full width at zero intensity of approximately 2400 km s‑1, an FWHM of 1200 ± 30 km s‑1, and an average net blueshift of 165 ± 10 km s‑1. The red wings of lines are increasingly absorbed toward longer wavelengths by material within the remnant. We conclude that the blast wave was sculpted by an aspherical circumstellar medium in which an equatorial density enhancement plays a role, as in earlier symbiotic nova explosions. Expansion of the dominant X-ray-emitting material is aligned close to the plane of the sky and is most consistent with an orbit seen close to face-on. Comparison of an analytical blast wave model with the X-ray spectra, Swift observations, and near-infrared line widths indicates that the explosion energy was approximately 1043 erg and confirms an ejected mass of approximately 10‑7 M ⊙. The total mass lost is an order of magnitude lower than the accreted mass required to have initiated the explosion, indicating that the white dwarf is gaining mass and is a Type Ia supernova progenitor candidate.

  8. Recurrent Nova M31N 2008-12a: The 2016 eruption may be imminent

    NASA Astrophysics Data System (ADS)

    Darnley, M. J.; Henze, M.

    2016-08-01

    The remarkable recurrent nova M31N 2008-12a has been observed undergoing eruptions eleven times, which includes annual eruptions between 2008 and 2015 (see Darnley et al. 2016, for a recent review), with the system having a predicted recurrence period of just under six months (Henze et al. 2015).

  9. A Luminous Red Nova in M31 and its Progenitor System

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Darnley, M. J.; Bode, M. F.; Steele, I. A.

    2015-06-01

    We present observations of M31LRN 2015 (MASTER OT J004207.99+405501.1), discovered in M31 in 2015 January, and identified as a rare and enigmatic luminous red nova (LRN). Spectroscopic and photometric observations obtained by the Liverpool Telescope showed the LRN becoming extremely red as it faded from its {{M}V}=-9.4+/- 0.2 peak. Early spectra showed strong Hα emission that weakened over time as a number of absorption features appeared, including Na i D and Ba ii. At later times strong TiO absorption bands were also seen. A search of archival Hubble Space Telescope data revealed a luminous red source to be the likely progenitor system, with pre-outburst Hα emission also detected in ground-based data. The outburst of M31LRN 2015 shows many similarities, both spectroscopically and photometrically, with that of V838 Mon, the best studied LRN. We finally discuss the possible progenitor scenarios.

  10. Spectroscopic Confirmation of the 2015 Eruption of Recurrent Nova M31N 1963-09c

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Darnley, M. J.; Henze, M.; Shafter, A. W.; Hornoch, K.

    2015-11-01

    We obtained an optical spectrum of the 2015 eruption of recurrent nova M31N 1963-09c (see ATel #8233, #8234, #8235, #8238 and CBAT TOCP) using the SPRAT spectrograph on the Liverpool Telescope (Steele et al. 2004) on 2015 November 2.93 UT. The spectrum shows extremely broad Balmer, He I, N II and N III emission features.

  11. Simulations of the Symbiotic Recurrent Nova V407 CYG. I. Accretion and Shock Evolutions

    NASA Astrophysics Data System (ADS)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E.

    2015-06-01

    The shock interaction and evolution of nova ejecta with wind from a red giant (RG) star in a symbiotic binary system are investigated via three-dimensional hydrodynamics simulations. We specifically model the 2010 March outburst of the symbiotic recurrent nova V407 Cygni from its quiescent phase to its eruption phase. The circumstellar density enhancement due to wind-white-dwarf interaction is studied in detail. It is found that the density-enhancement efficiency depends on the ratio of the orbital speed to the RG wind speed. Unlike another recurrent nova, RS Ophiuchi, we do not observe a strong disk-like density enhancement, but instead observe an aspherical density distribution with ˜20% higher density in the equatorial plane than at the poles. To model the 2010 outburst, we consider several physical parameters, including the RG mass-loss rate, nova eruption energy, and ejecta mass. A detailed study of the shock interaction and evolution reveals that the interaction of shocks with the RG wind generates strong Rayleigh-Taylor instabilities. In addition, the presence of the companion and circumstellar density enhancement greatly alter the shock evolution during the nova phase. Depending on the model, the ejecta speed after sweeping out most of the circumstellar medium decreases to ˜100-300 km s-1, which is consistent with the observed extended redward emission in [N ii] lines in 2011 April.

  12. Erratum - the 1989 Outburst of the Recurrent Nova V745-SCORPII

    NASA Astrophysics Data System (ADS)

    Sekiguchi, K.; Whitelock, P. A.; Feast, M. W.; Barrett, P. E.; Caldwell, J. A. R.; Carter, B. S.; Catchpole, R. M.; Laing, J. D.; Laney, C. D.; Marang, F.; van Wyk, F.

    1991-01-01

    The paper "The 1989 Outburst of the Recurrent Nova V745-SCORPII" was published in Mon. Not. R. astr. Soc. (1990) 246, 78-83. The ninth line of the Introduction has been misprinted. The correct version of the Introduction is reproduced below. INTRODUCTION: The first recorded outburst of V745 Sco (α = 17h52m04s.72, δ = -33° 14' 31".8; equinox 1950.0, McNaught 1989) was reported by Plaut (1958) who found the nova at mpυ ˜11.2 on 1937 May 10. It was classified as a nova on the basis of its outburst amplitude and light curve although no spectroscopic observations were reported (Duerbeck 1984, 1987). The second observed outburst was discovered by Liller (1989) on 1989 July 30.08 UT at a ˜9.7 mag. It was at a similar brightness on July 31.02 UT but had been fainter than magnitude 12 on July 29.549 UT (Honda 1989). In the following we will therefore assume that the nova reached maximum light on July 30.0 UT. The 1989 outburst places V745 Sco in the small class of recurrent novae, bringing their numbers up to seven. This paper presents the results of photometric and spectroscopic observations covering the most recent outburst.

  13. The White Dwarf Mass and the Accretion Rate of Recurrent Novae: An X-ray Perspective

    NASA Technical Reports Server (NTRS)

    Mukai, Koji; Sokoloski, Jennifer L.; Nelson, Thomas; Luna, Gerardo J. M.

    2011-01-01

    We present recent results of quiescent X-ray observations of recurrent novae (RNe) and related objects. Several RNe are luminous hard X-ray sources in quiescence, consistent with accretion onto a near Chandrasekhar mass white dwarf. Detection of similar hard X-ray emissions in old novae and other cataclysmic variables may lead to identification of additional RN candidates. On the other hand, other RNe are found to be comparatively hard X-ray faint. We present several scenarios that may explain this dichotomy, which should be explored further.

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

    NASA Astrophysics Data System (ADS)

    Munari, U.; Walter, F. M.; Hambsch, F.-J.; Frigo, A.

    2016-03-01

    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 =-7.15. A 1 day long 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. A recurrence period of 955 days would fit both the OGLE inter-season gaps and the observed intervals between previous outburts.

  15. The symbiotic recurrent nova V745 Sco is confirmed as a bright super-soft source.

    NASA Astrophysics Data System (ADS)

    Page, K. L.; Osborne, J. P.; Beardmore, A. P.; Mukai, K.; Starrfield, S.

    2014-02-01

    On 2014-02-10, Swift-XRT data collected on the recurrent nova V745 Sco showed an increase in soft counts, suggesting the onset of the super-soft source phase (Page et al., ATel #5870). Further data collected approximately 24 hours later showed a dramatic increase in the source count rate, almost entirely due to counts below 1 keV. We therefore confirm that V745 Sco is now in the supersoft emission phase.

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

    SciTech Connect

    Wilson, R. E.; Honeycutt, R. K. E-mail: rewilson@ufl.edu

    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.

  17. Swift UVOT detection of the recurrent nova M31N 1990-10a during its 2016 eruption

    NASA Astrophysics Data System (ADS)

    Henze, M.; Williams, S. C.; Darnley, M. J.; Ederoclite, A.; Sala, G.; Shafter, A. W.; Hornoch, K.

    2016-07-01

    A new eruption of the M31 recurrent nova M31N 1990-10a was discovered recently on July 27 (see ATel #9276). The last observed eruption took place in 2007 (ATel #1131), which suggests a recurrence period of merely 8-9 years.

  18. DYNAMICAL FRAGMENTATION OF THE T PYXIDIS NOVA SHELL DURING RECURRENT ERUPTIONS

    SciTech Connect

    Toraskar, Jayashree; Mac Low, Mordecai-Mark; Shara, Michael M.; Zurek, David R. E-mail: mordecai@amnh.org E-mail: dzurek@amnh.org

    2013-05-01

    Hubble Space Telescope images of the ejecta surrounding the nova T Pyxidis resolve the emission into more than 2000 bright knots. We simulate the dynamical evolution of the ejecta from T Pyxidis during its multiple eruptions over the last 150 years using the adaptive mesh refinement code Ramses. We demonstrate that the observed knots are the result of Richtmyer-Meshkov gas dynamical instabilities (the equivalent of Rayleigh-Taylor instabilities in an accelerated medium). These instabilities are caused by the overrunning of the ejecta from the classical nova of 1866 by fast-moving ejecta from the six subsequent recurrent nova outbursts. Magnetic fields may play a role in determining knot scale and preventing their conductive evaporation. The model correctly predicts the observed expansion and dimming of the T Pyx ejecta as well as the knotty morphology. The model also predicts that deeper, high-resolution imagery will show filamentary structure connecting the knots. We show reprocessed Hubble Space Telescope imagery that shows the first hints of such a structure.

  19. Active phases and flickering of a symbiotic recurrent nova T CrB

    NASA Astrophysics Data System (ADS)

    Iłkiewicz, Krystian; Mikołajewska, Joanna; Stoyanov, Kiril; Manousakis, Antonios; Miszalski, Brent

    2016-11-01

    T CrB is a symbiotic recurrent nova known to exhibit active phases, characterized by apparent increases in the hot component temperature and the appearance of flickering, i.e. changes in the observed flux on the time-scale of minutes. Historical UV observations have ruled out orbital variability as an explanation for flickering and instead suggest flickering is caused by variable mass transfer. We have analysed optical and X-ray observations to investigate the nature of the flickering as well as the active phases in T CrB. The spectroscopic and photometric observations confirm that the active phases follow two periods of ˜1000d and ˜5000d. Flickering in the X-rays is detected and follows an amplitude-flux relationship similar to that observed in the optical. The flickering is most prominent at harder X-ray energies, suggesting that it originates in the boundary layer between the accretion disc and the white dwarf. The X-ray radiation from the boundary layer is then reprocessed by a thick accretion disc or a nebula into UV radiation. A more detailed understanding of flickering would benefit from long-term simultaneous X-ray and optical monitoring of the phenomena in symbiotic recurrent novae and related systems such as Z And type symbiotic stars.

  20. The symbiotic binary system RX Puppis: a possible recurrent nova with a Mira companion

    NASA Astrophysics Data System (ADS)

    Mikolajewska, Joanna; Brandi, Estela; Hack, Warren; Whitelock, Patricia A.; Barba, Rodolfo; Garcia, Lia; Marang, Freddy

    1999-05-01

    We present an analysis of photometric and spectroscopic observations of the symbiotic binary system RX Pup with the aim of developing a reliable binary model for the system and identifying mechanisms responsible for its spectacular activity. The binary is composed of a long-period Mira variable surrounded by a thick dust shell and a hot ~ 0.8 M_sun white dwarf companion. The hot component produces practically all activity observed in the UV, optical and radio range, while variable obscuration of the Mira by circumstellar dust is responsible for long-term changes in the near-infrared magnitudes. The observations show that RX Pup underwent a nova-like eruption during the last three decades. The hot component contracted in radius at roughly constant luminosity from 1975 to 1986, and was the source of a strong stellar wind, which prevented it from accreting material lost in the Mira wind. Around 1988/9 the hot component turned over in the Hertzsprung-Russell (HR) diagram and by 1991 its luminosity had faded by a factor of ~ 30 with respect to the maximum plateau value and the hot wind had practically ceased. By 1995 the nova remnant started to accrete material from the Mira wind, as indicated by a general increase in intensity of the optical continuum and H I emission. The quiescent spectrum resembles the quiescent spectra of symbiotic recurrent novae, and its intensity indicates that the hot component must accrete as much as ~ 1 per cent of the Mira wind, which is more or less the amount predicted by Bondi-Hoyle theory. The earliest observational records from the 1890s suggest that another nova-like eruption of RX Pup occurred around 1894.

  1. NOVA.

    ERIC Educational Resources Information Center

    WGBH-TV, Boston, MA.

    News clippings, reviews, and feature articles about the Public Broadcasting System science-adventure series "Nova" are collected here. Included are comments from the New York Times, Washington Post, Christian Science Monitor, and TV Guide. Commentaries are primarily favorable and include synopses of various episodes. (DGC)

  2. The 2010 outburst and pre-outburst optical spectrum of the recurrent nova U Scorpii

    NASA Astrophysics Data System (ADS)

    Anupama, G. C.; Kamath, U. S.; Ramaprakash, A. N.; Kantharia, N. G.; Hegde, M.; Mohan, V.; Kulkarni, M.; Bode, M. F.; Eyres, S. P. S.; Evans, A.; O'Brien, T. J.

    2013-11-01

    Aims: We study the evolution of the recurrent nova U Scorpii during its outburst in 2010. Methods: Optical spectroscopic observations of the nova were obtained during 0.83-162.5 days after outburst maximum. Optical linear polarisation observations were made before the onset of the super soft X-ray source (SSS) phase and during the SSS phase. Radio continuum observations were made in the 1280 MHz band during the early decline phase, and in the 610 MHz band at the onset and end of the SSS phase. We also present optical spectra obtained in the pre-outburst quiescence phase. Results: The overall spectral evolution during the 2010 outburst is similar to the previous outbursts. However, the dense temporal coverage, especially during the early phases, reveals several short term variations not reported previously. The early phase emission line widths indicate extremely high velocities for the nova ejecta, ~10 000 km s-1. The line profiles are broad, boxy and structured. Narrow P-Cygni absorptions, at ~500 km s-1 are seen associated with the He I lines, and also the Ca II, N I and hydrogen lines (at wavelengths >8000 Å) in the spectrum of day 6.83, obtained immediately after an optical flare. This absorption component could be arising in the plasma emitting the Nitrogen lines seen in X-rays, that probably lies outside the binary orbit. Rapid variations are detected in the strength of the 4660 Å N III feature, which shows a significant increase in the line strength on days 8.83 and 13.82, at orbital phases of 0.75 and 0.25, respectively. Instrinsic polarisation is detected just before the onset, and during the SSS phase, with pv ~ 1.4% during the SSS phase. The flux variations of the N III feature and the intrinsic polarisation are most likely associated with the reforming accretion disc/stream. We estimate the mass of the ejected (hydrogen) shell to be ~4.6 × 10-6 M⊙, for a spherical shell geometry. The non-detection of U Sco in the 1280 MHz and 610 MHz radio bands is

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

    SciTech Connect

    Godon, Patrick; Sion, Edward M.; Starrfield, Sumner; Livio, Mario; Williams, Robert E.; Woodward, Charles E.; Kuin, Paul; Page, Kim L. E-mail: edward.sion@villanova.edu E-mail: mlivio@stsci.edu E-mail: chelsea@astro.umn.edu E-mail: klp5@leicester.ac.uk

    2014-04-01

    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{sup –5} M {sub ☉} to 3.3 × 10{sup –4} M {sub ☉}, and assuming a mass accretion rate of 10{sup –8}-10{sup –7} M {sub ☉} yr{sup –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 {sub ☉} ≤ M {sub wd} ≤ 1.35 M {sub ☉}) 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 {sub ☉} and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.

  4. ECLIPSES DURING THE 2010 ERUPTION OF THE RECURRENT NOVA U SCORPII

    SciTech Connect

    Schaefer, Bradley E.; Pagnotta, Ashley; LaCluyze, Aaron P.; Reichart, Daniel E.; Ivarsen, Kevin M.; Haislip, Joshua B.; Nysewander, Melissa C.; Moore, Justin P.; Oksanen, Arto; Worters, Hannah L.; Sefako, Ramotholo R.; Mentz, Jaco; Dvorak, Shawn; Gomez, Tomas; Harris, Barbara G.; Henden, Arne A.; Tan, Thiam Guan; Templeton, Matthew; Allen, W. H.; Monard, Berto; and others

    2011-12-01

    The eruption of the recurrent nova U Scorpii on 2010 January 28 is now the all-time best observed nova event. We report 36,776 magnitudes throughout its 67 day eruption, for an average of one measure every 2.6 minutes. This unique and unprecedented coverage is the first time that a nova has had any substantial amount of fast photometry. With this, two new phenomena have been discovered: the fast flares in the early light curve seen from days 9-15 (which have no proposed explanation) and the optical dips seen out of eclipse from days 41-61 (likely caused by raised rims of the accretion disk occulting the bright inner regions of the disk as seen over specific orbital phases). The expanding shell and wind cleared enough from days 12-15 so that the inner binary system became visible, resulting in the sudden onset of eclipses and the turn-on of the supersoft X-ray source. On day 15, a strong asymmetry in the out-of-eclipse light points to the existence of the accretion stream. The normal optical flickering restarts on day 24.5. For days 15-26, eclipse mapping shows that the optical source is spherically symmetric with a radius of 4.1 R{sub Sun }. For days 26-41, the optical light is coming from a rim-bright disk of radius 3.4 R{sub Sun }. For days 41-67, the optical source is a center-bright disk of radius 2.2 R{sub Sun }. Throughout the eruption, the colors remain essentially constant. We present 12 eclipse times during eruption plus five just after the eruption.

  5. Additional optical photometry of the recurrent nova M31N 1990-10a during its 2016 eruption

    NASA Astrophysics Data System (ADS)

    Goranskij, V.; Barsukova, E.; Henze, M.

    2016-08-01

    We report additional optical measurements of the declining light curve of the recurrent nova M31N 1990-10a (see ATels #9276,#9280,#9281,#9383,#9386). All data were obtained with the 50-cm Maksutov meniscus telescope of the Crimean Astronomical Station of the Moscow University.

  6. A pre-outburst signal in the long-term optical light curve of the recurrent nova RS Ophiuchi

    NASA Astrophysics Data System (ADS)

    Adamakis, S.; Eyres, S. P. S.; Sarkar, A.; Walsh, R. W.

    2011-07-01

    Recurrent novae are binary stars in which a white dwarf accretes matter from a less evolved companion, either a red giant or a main-sequence star. They have dramatic optical brightenings of around 5-6 mag in V in less than a day, several times a century. These occur at variable and unpredictable intervals, and are followed by an optical decline over several weeks and activity from the X-ray to the radio. The unpredictability of recurrent novae and related stellar types can hamper systematic study of their outbursts. Here we analyse the long-term light curve of RS Ophiuchi, a recurrent nova with six confirmed outbursts, most recently in 2006 February. We confirm the previously suspected 1945 outburst, largely obscured in a seasonal gap. We also find a signal via wavelet analysis that can be used to predict an incipient outburst up to a few hundred days before hand. This has never before been possible. In addition, this may suggest that the preferred thermonuclear runaway mechanism for the outbursts will have to be modified, as no pre-outburst signal is anticipated in that case. If our result indeed points to gaps in our understanding of how outbursts are driven, we will need to study such objects carefully to determine if the white dwarf is growing in mass, an essential factor if these systems are to become Type Ia supernovae. Determining the likelihood of recurrent novae being an important source population will have implications for stellar and galaxy evolution.

  7. The Recurrent Nova T CrB Did Not Erupt In 1842

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.

    2013-01-01

    The recurrent nova T CrB was one of the first well observed nova eruptions in 1866, and 80 years later it erupted again in 1946. Just after the 1866 eruption, Sir John Herschel reported to the Monthly Notices that he had seen the same star in his naked-eye charting of the sky on 1842 June 9, implying that there was a prior eruption 24 years earlier, with substantial implications for astrophysics. Unfortunately, the chart in the Monthly Notices was ambiguous and misleading, including whether the recorded position is or is not that of T CrB. So it has long been unclear whether T CrB did indeed have an eruption in 1842. To resolve this, I have made complete searches through the various archives with Herschel material, including the large collections at the Harry Ransom Center in Austin, the Royal Astronomical Society, the complete Herschel correspondence, and the Royal Society; plus three smaller archives as well as consulting with various Herschel experts. In one letter from 1866 to William Huggins, Herschel enclosed his own copy of his original observations, and with this all the ambiguities are resolved. It turns out that Herschel's indicated star was at the same position as a steady background star (BD+25 3020, V=7.06, G8V) and not that of T CrB, and Herschel regularly was seeing stars as faint as V=7.5 mag because he was using an opera glass. With this, there is no evidence for a T CrB eruption in 1842. Supported by the National Science Foundation.

  8. FROM X-RAY DIPS TO ECLIPSE: WITNESSING DISK REFORMATION IN THE RECURRENT NOVA U Sco

    SciTech Connect

    Ness, J.-U.; Talavera, A.; Gonzalez-Riestra, R.; Schaefer, B. E.; Dobrotka, A.; Sadowski, A.; Drake, J. J.; Barnard, R.; Page, K. L.; Hernanz, M.; Sala, G.; Starrfield, S.

    2012-01-20

    The tenth recorded outburst of the recurrent eclipsing nova U Sco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV and optical but deep dips in the X-ray light curve that disappeared by day 34.9, yielding clean eclipses in all bands. X-ray dips can be caused by clumpy absorbing material that intersects the line of sight while moving along highly elliptical trajectories. Cold material from the companion could explain the absence of dips in UV and optical light. The disappearance of X-ray dips before day 34.9 implies significant progress in the formation of the disk. The X-ray spectra contain photospheric continuum emission plus strong emission lines, but no clear absorption lines. Both continuum and emission lines in the X-ray spectra indicate a temperature increase from day 22.9 to day 34.9. We find clear evidence in the spectra and light curves for Thompson scattering of the photospheric emission from the white dwarf. Photospheric absorption lines can be smeared out during scattering in a plasma of fast electrons. We also find spectral signatures of resonant line scattering that lead to the observation of the strong emission lines. Their dominance could be a general phenomenon in high-inclination systems such as Cal 87.

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

    SciTech Connect

    Nelson, Thomas; Chomiuk, Laura; Roy, Nirupam; Krauss, Miriam I.; Mioduszewski, Amy J.; Rupen, Michael P.; Sokoloski, J. L.; Weston, Jennifer; Mukai, Koji

    2014-04-10

    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{sup –5} M {sub ☉}. 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.

  10. Spectral classification of the recurrent nova M31N 1990-10a during its 2016 eruption with BTA/Scorpio

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Sholukhova, O.; Valeev, A.; Burenkov, A.; Makarov, D.; Henze, M.; Williams, S. C.; Darnley, M. J.; Shafter, A. W.; Hornoch, K.; Ederoclite, A.; Sala, G.

    2016-08-01

    We report optical spectroscopy and photometry of the recurrent nova M31N 1990-10a during its 2016 eruption (see ATels #9276,#9280,#9281). We confirm the first spectrum obtained in ATel #9281 and describe the spectral evolution of the nova.

  11. Optical flickering of the recurrent nova RS Ophiuchi: amplitude-flux relation

    NASA Astrophysics Data System (ADS)

    Zamanov, R.; Latev, G.; Boeva, S.; Sokoloski, J. L.; Stoyanov, K.; Bachev, R.; Spassov, B.; Nikolov, G.; Golev, V.; Ibryamov, S.

    2015-07-01

    We report observations of the flickering variability of the symbiotic recurrent nova RS Oph at quiescence in five bands (UBVRI). We find evidence of a correlation between the peak-to-peak flickering amplitude (ΔF) and the average flux of the hot component (Fav). The correlation is highly significant, with a correlation coefficient of 0.85 and a p-value of ˜10-20. Combining the data from all wavebands, we find a dependence of the type Δ F ∝ F_{av}^k, with power-law index k = 1.02 ± 0.04 for the UBVRI flickering of RS Oph. Thus, the relationship between the amplitude of variability and the average flux of the hot component is consistent with linearity. The rms amplitude of flickering is on average 8 per cent (±2 per cent) of Fav. The detected correlation is similar to that found in accreting black holes/neutron stars and cataclysmic variables. The possible reasons are briefly discussed. The data are available upon request from the authors.

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

    SciTech Connect

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

    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.

  13. Assisted stellar suicide: the wind-driven evolution of the recurrent nova T Pyxidis

    NASA Astrophysics Data System (ADS)

    Knigge, Ch.; King, A. R.; Patterson, J.

    2000-12-01

    We show that the extremely high luminosity of the short-period recurrent nova T Pyx in quiescence can be understood if this system is a wind-driven supersoft x-ray source (SSS). In this scenario, a strong, radiation-induced wind is excited from the secondary star and accelerates the binary evolution. The accretion rate is therefore much higher than in an ordinary cataclysmic binary at the same orbital period, as is the luminosity of the white dwarf primary. In the steady state, the enhanced luminosity is just sufficient to maintain the wind from the secondary. The accretion rate and luminosity predicted by the wind-driven model for T Pyx are in good agreement with the observational evidence. X-ray observations with Chandra or XMM may be able to confirm T Pyx's status as a SSS. T Pyx's lifetime in the wind-driven state is on the order of a million years. Its ultimate fate is not certain, but the system may very well end up destroying itself, either via the complete evaporation of the secondary star, or in a Type Ia supernova if the white dwarf reaches the Chandrasekhar limit. Thus either the primary, the secondary, or both may currently be committing assisted stellar suicide.

  14. THE CHANGE OF THE ORBITAL PERIODS ACROSS ERUPTIONS AND THE EJECTED MASS FOR RECURRENT NOVAE CI AQUILAE AND U SCORPII

    SciTech Connect

    Schaefer, Bradley E.

    2011-12-01

    I report on the cumulative results from a program started 24 years ago designed to measure the orbital period change of recurrent novae (RNe) across an eruption. The goal is to use the orbital period change to measure the mass ejected during each eruption as the key part of trying to measure whether the RNe white dwarfs are gaining or losing mass over an entire eruption cycle, and hence whether they can be progenitors for Type Ia supernovae. This program has now been completed for two eclipsing RNe: CI Aquilae (CI Aql) across its eruption in 2000 and U Scorpii (U Sco) across its eruption in 1999. For CI Aql, I present 78 eclipse times from 1991 to 2009 (including four during the tail of the 2000 eruption) plus two eclipses from 1926 and 1935. For U Sco, I present 67 eclipse times, including 46 times during quiescence from 1989 to 2009, plus 21 eclipse times in the tails of the 1945, 1999, and 2010 eruptions. The eclipse times during the tails of eruptions are systematically and substantially shifted with respect to the ephemerides from the eclipses in quiescence, with this being caused by shifts of the center of light during the eruption. These eclipse times are plotted on an O - C diagram and fitted to models with a steady period change ( P-dot ) between eruptions (caused by, for example, conservative mass transfer) plus an abrupt period change ({Delta}P) at the time of eruption. The primary uncertainty arises from the correlation between {Delta}P with P-dot , such that a more negative P-dot makes for a more positive {Delta}P. For CI Aql, the best fit is {Delta}P = -3.7{sup +9.2}{sub -7.3} Multiplication-Sign 10{sup -7}. For U Sco, the best fit is {Delta}P = (+ 43 {+-} 69) Multiplication-Sign 10{sup -7} days. These period changes can directly give a dynamical measure of the mass ejected (M{sub ejecta}) during each eruption with negligible sensitivity to the stellar masses and no uncertainty from distances. For CI Aql, the 1{sigma} upper limit is M{sub ejecta} < 10

  15. X-ray Flashes in Recurrent Novae: M31N 2008-12a and the Implications of the Swift Nondetection

    NASA Astrophysics Data System (ADS)

    Kato, Mariko; Saio, Hideyuki; 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

    2016-10-01

    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}ȯ and for two recurrence periods of 0.5 and 1 yr. 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 hr (0.6 days) among the four cases is obtained for the 1.385 {M}ȯ WD with a 1 yr 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 yr recurrence period), which resulted in the nondetection of X-ray emission during the period of 8 days before the optical detection. We discuss the impact of these observations on nova outburst theory. The X-ray flash is one of the last frontiers of nova studies, and its detection is essential for understanding the pre-optical-maximum phase. We encourage further observations.

  16. A Model for the Quiescent Phase of the Recurrent Nova U Scorpii

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko; Kato, Taichi; Matsumoto, Katsura; Nomoto, Ken'ichi

    2000-05-01

    A theoretical light curve is constructed for the quiescent phase of the recurrent nova U Scorpii in order to resolve the existing distance discrepancy between the outbursts (d~6 kpc) and the quiescences (d~14 kpc). Our U Sco model consists of a very massive white dwarf (WD), an accretion disk (ACDK) with a flaring-up rim, and a lobe-filling, slightly evolved, main-sequence star (MS). The model properly includes an accretion luminosity of the WD, a viscous luminosity of the ACDK, and a reflection effect of the MS and the ACDK irradiated by the WD photosphere. The B light curve is well reproduced by a model of 1.37 Msolar WD + 1.5 Msolar MS (0.8-2.0 Msolar MS is acceptable) with an ACDK having a flaring-up rim and the inclination angle of the orbit i~80deg. The calculated color is rather blue (B-V~0.0) for a suggested mass accretion rate of 2.5×10-7 Msolar yr-1, thus indicating a large color excess of E(B-V) ~ 0.56 with the observational color of B-V=0.56 in quiescence. Such a large color excess corresponds to an absorption of AV~1.8 and AB~2.3, which reduces the distance to 6-8 kpc. This is in good agreement with the distance estimation of 4-6 kpc for the latest outburst. Such a large intrinsic absorption is very consistent with the recently detected period change of U Sco, which is indicating a mass outflow of ~3×10-7 Msolar yr-1 through the outer Lagrangian points in quiescence.

  17. M31N 1923-12c is a recurrent nova in M31

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.; Darnley, M. J.; Bode, M. F.; Ciardullo, R.; Schweizer, F.

    2012-02-01

    A spectrum of PNV J00423804+4108417 (tentatively designated M31N 2012-01b) recently reported by Shafter et al. (ATel #3877) revealed the object to be a He/N nova in M31. A subsequent comparison of its position (R.A. = 00h 42m 38.04s; Decl. = 41deg 08' 41.7", J2000) with the ~900 novae in W. Pietsch's M31 nova catalog (http://www.mpe.mpg.de/~m31novae/opt/m31/M31_table.html) revealed that PNV J00423804+4108417 was apparently located ~6" from the cataloged position of M31N 1923-12c, a nova discovered by Edwin Hubble on December 11, 1923.

  18. A remarkable recurrent nova in M 31: The predicted 2014 outburst in X-rays with Swift

    NASA Astrophysics Data System (ADS)

    Henze, M.; Ness, J.-U.; Darnley, M. J.; Bode, M. F.; Williams, S. C.; Shafter, A. W.; Sala, G.; Kato, M.; Hachisu, I.; Hernanz, M.

    2015-08-01

    Context. The M 31 nova M31N 2008-12a was recently found to be a recurrent nova (RN) with a recurrence time of about one year. This is by far the fastest recurrence time scale of any known RN. Aims: Our optical monitoring programme detected the predicted 2014 outburst of M31N 2008-12a in early October. We immediately initiated an X-ray/UV monitoring campaign with Swift to study the multiwavelength evolution of the outburst. Methods: We monitored M31N 2008-12a with daily Swift observations for 20 days after discovery, covering the entire supersoft X-ray source (SSS) phase. Results: We detected SSS emission around day six after outburst. The SSS state lasted for approximately two weeks until about day 19. M31N 2008-12a was a bright X-ray source with a high blackbody temperature. Conclusions: The X-ray properties of this outburst are very similar to the 2013 eruption. Combined X-ray spectra show a fast rise and decline of the effective blackbody temperature. The short-term X-ray light curve showed strong, aperiodic variability which decreased significantly after about day 14. Overall, the X-ray properties of M31N 2008-12a are consistent with the average population properties of M 31 novae. The optical and X-ray light curves can be scaled uniformly to show similar time scales to those of the Galactic RNe U Sco or RS Oph. The SSS evolution time scales and effective temperatures are consistent with a high-mass WD. We predict the next outburst of M31N 2008-12a to occur in Oct.-Dec. 2015. Tables 1-3 are available in electronic form at http://www.aanda.org

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

    NASA Technical Reports Server (NTRS)

    Chomiuk, Laura; Nelson, Thomas; Mukai, Koji; Solokoski, 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 (approximately 45 electron volts) and implies that the white dwarf in T Pyx is significantly below the Chandrasekhar mass (approximately 1 M). The late turn-on time of the super-soft component yields a large nova ejecta mass (approximately greater than 10(exp -5) solar mass), consistent with estimates at other wavelengths. The hard X-ray component is well fit by a approximately 1 kiloelectron volt 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.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

    Chomiuk, Laura; Nelson, Thomas; 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.

    2014-06-01

    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 ⊙). The late turn-on time of the super-soft component yields a large nova ejecta mass (gsim 10-5 M ⊙), 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.

  2. Spectral classification of the recurrent nova M31N 1990-10a during its 2016 eruption with WHT/ACAM

    NASA Astrophysics Data System (ADS)

    Ederoclite, A.; Henze, M.; Aguado, D.; Allende, C.; Williams, S.; Darnley, M. J.; Sala, G.; Shafter, A. W.; Hornoch, K.

    2016-07-01

    An optical spectrum of the fast recurrent nova candidate M31N 1990-10a (see ATels #9276,#9280) was obtained on 2016-07-30.11 UT with the ACAM instrument on the 4m William Herschel Telescope at the Roque de los Muchachos Observatory (located in La Palma, Spain).

  3. DISCOVERY OF THE PREDICTED 2010 ERUPTION AND THE PRE-ERUPTION LIGHT CURVE FOR RECURRENT NOVA U SCORPII

    SciTech Connect

    Schaefer, Bradley E.; Pagnotta, Ashley; Xiao Limin; Darnley, Matthew J.; Bode, Michael F.; Harris, Barbara G.; Dvorak, Shawn; Menke, John; Linnolt, Michael; Templeton, Matthew; Henden, Arne A.; Pojmanski, Grzegorz; Pilecki, Bogumil; Szczygiel, Dorota M.; Watanabe, Yasunori

    2010-10-15

    We report the discovery by B. G. Harris and S. Dvorak on JD 2455224.9385 (2010 January 28.4385 UT) of the predicted eruption of the recurrent nova U Scorpii (U Sco). We also report 815 magnitudes (and 16 useful limits) on the pre-eruption light curve in the UBVRI and Sloan r' and i' bands from 2000.4 up to 9 hr before the peak of the 2010 January eruption. We found no significant long-term variations, though we did find frequent fast variations (flickering) with amplitudes up to 0.4 mag. We show that U Sco did not have any pre-eruption rises or dips with an amplitude greater than 0.2 mag on timescales from one day to one year before the eruption. We find that the peak of this eruption occurred at JD 2455224.69 {+-} 0.07 and the start of the rise was at JD 2455224.32 {+-} 0.12. From our analysis of the average B-band flux between eruptions, we find that the total mass accreted between eruptions is consistent with being a constant, in agreement with a strong prediction of nova trigger theory. The date of the next eruption can be anticipated with an accuracy of {+-}5 months by following the average B-band magnitudes for the next {approx}10 years, although at this time we can only predict that the next eruption will be in the year 2020 {+-} 2.

  4. The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst. I. The optically thick phase and the origin of moving lines in novae

    NASA Astrophysics Data System (ADS)

    Shore, S. N.; Augusteijn, T.; Ederoclite, A.; Uthas, H.

    2011-09-01

    Aims: We aim to derive the physical properties of the recurrent nova T Pyx and the structure of the ejecta during the early stages of expansion of the 2011 outburst. Methods: The nova was observed with high resolution spectroscopy (R ≈ 65 000), from one day after discovery of the outburst and until the last visibility of the star at the end of May 2011. The interstellar absorption lines of Na I, Ca II, CH, CH+, and archival H I 21 cm emission line observations were used to determine a kinematical distance. Interstellar diffuse absorption features have been used to determine the extinction independent of previous assumptions. Sample Fe-peak line profiles show the optical depth and radial velocity evolution of the discrete components. Results: We propose a distance to T Pyx ≥ 4.5 kpc, with a strict lower limit of 3.5 kpc (the previously accepted distance). We derive an extinction, E(B - V) ≈ 0.5 ± 0.1, that is higher than previous estimates. The first observation, Apr. 15, displayed He I, He II, C III, and N III emission lines and a maximum velocity derived from the P Cyg profiles of the Balmer and He I lines of ≈2500 km s-1 that is characteristic of the fireball stage. These ions were undetectable in the second spectrum, Apr. 23, and we use the recombination time to estimate the mass of the ejecta, 10-5f M⊙ for a filling factor f. Numerous absorption-line systems were detected in the Balmer, Fe-peak, Ca II, and Na I lines, mirrored in broader emission-line components, that showed an "accelerated" displacement in velocity. We also show that the time sequence of these absorptions, which are common to all lines and arise only in the ejecta, can be described by a recombination front moving outward in the expanding gas without either a stellar wind or circumstellar collisions. By the end of May, the ejecta were showing signs of turning optically thin in the ultraviolet. Appendices are available in electronic form at http://www.aanda.org

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

    NASA Technical Reports Server (NTRS)

    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

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

    SciTech Connect

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

    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 }.

  7. Dwarf novae

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    Dwarf novae are defined on grounds of their semi-regular brightness variations of some two to five magnitudes on time scales of typically 10 to 100 days. Historically several different classification schemes have been used. Today, dwarf novae are divided into three sub-classes: the U Geminorum stars, the SU Ursae Majoris stars, and the Z Camelopardalis stars. Outbursts of dwarf novae occur at semi-periodic intervals of time, typically every 10 to 100 days; amplitudes range from typically 2 to 5 mag. Within certain limits values are characteristic for each object. Relations between the outburst amplitude, or the total energy released during outburst, and the recurrence time have been found, as well as relations between the orbital period and the outburst decay time, the absolute magnitude during outburst maximum, and the widths of long and short outbursts, respectively. Some dwarf novae are known to have suspended their normal outburst activity altogether for a while. They later resumed it without having undergone any observable changes. The optical colors of dwarf novae all are quite similar during outburst, considerably bluer than during the quiescent state. During the outburst cycle, characteristic loops in the two color diagram are performed. At a time resolution on the order of minutes, strictly periodic photometric changes due to orbital motion become visible in the light curves of dwarf novae. These are characteristic for each system. Remarkably little is known about orbital variations during the course of an outburst. On time-scales of minutes and seconds, further more or less periodic types of variability are seen in dwarf novae. Appreciable flux is emitted by dwarf novae at all wavelengths from the X-rays to the longest IR wavelengths, and in some cases even in the radio. Most dwarf novae exhibit strong emission line spectra in the optical and UV during quiescence, although some have only very weak emissions in the optical and/or weak absorptions at UV

  8. PHOTOMETRIC AND SPECTROSCOPIC PROPERTIES OF NOVAE IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Shafter, A. W.

    2013-05-15

    The photometric and spectroscopic properties of the 43 known LMC nova candidates are summarized and reviewed. Of these, photometric data sufficient to establish decline rates are available for 29 novae, while spectroscopic data sufficient to establish the spectroscopic classes are available for 18 systems. Half of the 18 novae belong to the Fe II class, with the remaining nine belonging to either the He/N or the Fe IIb classes. As seen in previous nova studies of M31 and M33, the He/N and Fe IIb novae have on average faster photometric developments than do their Fe II counterparts. Overall, the available photometry confirms earlier studies, and shows conclusively that LMC novae have faster rates of decline than do novae in the Galaxy and M31. It appears that the increased fraction of faster, He/N and Fe IIb novae observed in the LMC compared with M31 is almost certainly the result of differences in the underlying stellar population between the two galaxies. We propose that the younger population seen in the LMC compared with M31's bulge (where most of the novae are found), produces progenitor binaries with higher average white dwarf masses. The higher mean white dwarf mass not only produces a larger fraction of fast, He/N novae compared with M31, but also results in a relatively large recurrent nova population.

  9. Search for soft X-ray flashes at the fireball phase of classical/recurrent novae using MAXI/GSC data

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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 the Gas Slit Camera (GSC) of the Monitor of All-sky X-ray Image (MAXI). We first developed a tool to measure the fluxes of point sources by fitting the event distribution with a 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 the 3 σ level in the energy range of 2-4 keV between td - 10 d and td, where td 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 with a mass of roughly 1.40 solar mass, or larger, in binary systems.

  10. The Spectroscopic Evolution of the Symbiotic-like Recurrent Nova V407 Cygni During Its 2010 Outburst. 2. The Circumstellar Environment and the Aftermath

    NASA Technical Reports Server (NTRS)

    Shore, S. N.; Wahlgren, G. M.; Augusteijn, T.; Liimets, T.; Koubsky, P.; Slechta, M.; Votruba, V.

    2011-01-01

    The nova outburst of V407 Cyg in 2010 Mar. 10 was the first observed for this star but its close resemblance to the well known symbiotic-like recurrent nova RS Oph suggests that it is also a member of this rare type of Galactic novae. The nova was the first detected at gamma-ray energies and is the first known nova explosion for this system. The extensive multiwavelength coverage of this outburst makes it an ideal comparison with the few other outbursts known for similar systems. We extend our previous analysis of the Mira and the expanding shock from the explosion to detail the time development of the photoionized Mira wind, circumstellar medium, and shocked circumstellar environment to derive their physical parameters and how they relate to large scale structure of the environment, extending the previous coverage to more than 500 days after outburst. We use optical spectra obtained at high resolution with the Nordic Optical Telescope (NOT) (R approx. =.45000 to 65000) and medium resolution Ondrejov Observatory (R approx. = 12000) data and compare the line variations with publicly available archival measurements at 30 GHz OVNR and at X-rays with Swift during the first four months of the outburst, through the end of the epoch of strong XR emission. We use nebular diagnostics and high resolution profile variations to derive the densities and locations of the extended emission. We find that the higher the ionization and/or the higher the excitation energy, the more closely the profiles resemble the He II/Ca V-type high velocity shock profile discussed in Paper I. This also accounts for the comparative development of the [N II] and [O III] isoelectronic transitions: the [O III] 4363A profile does not show the low velocity peaks while the excited [N II] 5754A does. If nitrogen is mainly N(+3) or higher in the shock, the upper state of the [N II] nebular lines will contribute but if the oxygen is O(+2) then this line is formed by recombination, masking the nebular

  11. The Nova Outburst: Thermonuclear Runaways on Degenerated Dwarfs

    SciTech Connect

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

    1999-07-08

    Observational and theoretical studies of the outbursts of classical novae have provided critical insights into a broad range of astrophysical phenomena. Thermonuclear runaways (TNRs) in accreted hydrogen-rich envelopes on the white dwarf (WD) components of close binary systems constitute not only the outburst mechanism for a classical nova explosion, but also the recurrent novae and a fraction of the symbiotic novae explosions. Studies of the general characteristics of these explosions, both in our own galaxy and in neighboring galaxies of varying metallicity, can teach us about binary stellar evolution, while studies of the evolution of nova binary systems can constrain models for the (as yet unidentified) progenitors of Type Ia supernovae. Further, the empirical relation between the peak luminosity of a nova and the rate of decline, which presents a challenge to theoretical models, allows novae to be utilized as standard candles for distance determinations out to the Virgo Cluster. E xtensive studies of novae with IUE and the resulting abundance determinations have revealed the existence of oxygen-neon white dwarfs in some systems. The high levels of enrichment of novae ejecta in elements ranging from carbon to sulfur confirm that there is significant dredge-up of matter from the core of the underlying white dwarf and enable novae to contribute to the chemical enrichment of the interstellar medium. Observations of the epoch of dust formation in the expanding shells of novae allow important constraints to be placed on the dust formation process and confirm that graphite, SiC, and SiO{sub 2} grains are formed by the outburst. It is possible that grains from novae were injected into the pre-solar nebula and can be identified with some of the pre-solar grains or ''stardust'' found in meteorites. Finally, g-ray observations during the first several years of their outburst, using the next generation of satellite observatories, could confirm

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

    NASA Astrophysics Data System (ADS)

    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.

  13. The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst. III. The ultraviolet development from iron curtain through the post-X-ray turnoff

    NASA Astrophysics Data System (ADS)

    De Gennaro Aquino, I.; Shore, S. N.; Schwarz, G. J.; Mason, E.; Starrfield, S.; Sion, E. M.

    2014-02-01

    We continue the analysis of the multiwavelength evolution of the recurrent nova T Pyx during its 2011 outburst, focussing on the spectral development on the 1150-3000 Å region. This extraordinary data set presents the longest temporal baseline high resolution view of the ultraviolet for any nova to date (classical or recurrent). The observations cover the early Fe-curtain stage, when the UV was completely optically thick, to 834 days after discovery when the outburst was effectively over. We present an analysis of dynamics and abundances of the interstellar species whose resonance lines are accessible in the UV. The Lyα profile is consistent with only interstellar absorption at all epochs and agrees with the H I 21 cm column density. The distance obtained to T Pyx is about 5 kpc, based on the ISM analysis. For the ejecta evolution we have been able to follow the changes in ionization and structure with previously unobtained resolution and cadence. The excited state isoelectronic transitions of C III, N IV], and O V displayed the same detached absorption lines as the optical He I transitions during the optical maximum. This is explained as resonance absorption within the ejecta of FUV ground state lines from the 300-1000 Å range. The resonance lines of all species showed absorption components between -1000 and -3000 km s-1 as soon as the Fe-curtain turned transparent (from day 105); these persisted at the same velocities and varied in strength from one ion to another through day 834. The last ultraviolet spectrum, taken more than 800 days after outburst, showed the same absorption lines on N V and C IV as day 105. There was no evidence of circumstellar absorbers. This and the related observations of profile evolution effectively rule out any wind model for the spectrum. The picture that emerges is of ejecta that became optically thin after visual maximum as the X-ray emission became visible following an outwardly propagating ionization front and for which the

  14. A Long Term High-Cadence Nova Survey

    NASA Astrophysics Data System (ADS)

    Castelaz, Michael W.; Rottler, L.; Barker, T.; Coker, M.

    2014-01-01

    We have initiated a nova survey that uses a previously unstudied long term high cadence archive data set covering about 1/3 of the sky to 1) improve on the number and recurrence frequency of recurrent novae (RNe), and 2) permit an investigation of the puzzling and diverse set of features in classical novae (CNe) and RNe light curves. RNe are of great astrophysical interest because they have long been considered to be the prime candidates for progenitors of Type Ia supernovae. However, the recurrence time scale is not well known, but is an essential parameter determining whether any RNe become Type Ia supernovae. Novae exhibit a wide variety of light curves with features like pre-eruption rises and dips, flat-tops at peak, and flares superimposed on decline, for example. These features are poorly understood. The answers require more and better light curves. The data set our team is using to address RNe occurrence and light curves was taken in the 1950’s over a nearly 9 year period with two Baker Super-Schmidt telescopes 80 km apart in New Mexico, resulting in 42,000 photographic images. Each telescope had a 52 degree field of view. Images to a limiting stellar magnitude of 13 were taken at a rate of 2-3 per hour sampling a total of one-third of the entire sky. A similar data set does not exist anywhere else, nor is one planned with such high cadence and field of view. We are digitizing the films and through a data pipeline plan to identify candidate RNe and new CNe enhancing the number of known RNe and creating light curves leading up to and following novae eruptions. We will describe the digitizing process and data pipeline, and initial results from the first 1,600 films that we have surveyed.

  15. Modelling nova populations in galaxies

    NASA Astrophysics Data System (ADS)

    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.

  16. SN 2010U: A LUMINOUS NOVA IN NGC 4214

    SciTech Connect

    Humphreys, Roberta M.; Helton, L. Andrew; Prieto, Jose L.; Rosenfield, Philip; Williams, Benjamin; Murphy, Jeremiah; Dalcanton, Julianne; Gilbert, Karoline; Kochanek, Christopher S.; Stanek, K. Z.; Khan, Rubab; Szczygiel, Dorota; Mogren, Karen; Fesen, Robert A.; Milisavljevic, Dan

    2010-07-20

    The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

  17. The fist homogeneous, multi-color photometric and spectroscopic sample of Stripped Envelope Super Novae and what it can tell us about their progenitors

    NASA Astrophysics Data System (ADS)

    Bianco, Federica; Modjaz, Maryam; Liu, Yuqian; CfA supernova Group

    2015-01-01

    Stripped envelope supernovae (stripped SN) arise from the spectacular death of massive stars which have lost their outer layers of Hydrogen and Helium in the late stages of their lives. They hold clues to study the final stages of the life of massive stars and the chemical enrichment of the Universe, and are intrinsically as common as SN type Ia. However, they have been observed and studied far less than SN Ia. The scarcity of data has thus far impaired the detailed study of their characteristics and a clear picture of the progenitor channels still eludes us.The CfA produced the first large stripped SN survey that includes multi-color photometry in the optical and NIR (Bianco et al. 2014) as well as spectroscopy (Modjaz et al. 2014) of over 50 stripped SN. This dataset allows us to accurately derive bolometric lightcurves, and measure ejecta velocities in a consistent fashion for the entire sample. We can set constraints on the ejecta masses of SN IIb, Ib, Ic and Ic-BL, and probe the diversity in the explosions and in the progenitor channels. The study of our sample allows a direct comparison of the ejecta characteristics with the outcome of recent stellar evolution studies, confirming that binary evolution plays an important role in the late stages of the life of high mass stars.

  18. Investigation of the Nebular Remnants of Novae

    NASA Astrophysics Data System (ADS)

    Ribeiro, Valério A. R. M.

    2011-01-01

    Classical and recurrent nova outbursts occur on the surface of a white dwarf in a close binary system. It is widely established that the outburst is due to a thermonuclear runaway. Their study provides a real-time laboratory for the understanding of a wide range of astrophysical phenomena. These include for example, mass transfer in close binary systems, nuclear powered outbursts, dust formation, mass loss from red giants, and many others. Recurrent novae have also been suggested as the progenitors of Type Ia Supernovae. This thesis concentrates on investigating the nebular remnants of novae by studying both resolved imaging (where available) and spectroscopic evolution and combining this with detailed modelling. Such studies have wider implications for example in our understanding of the shaping of proto-Planetary Nebulae. Here, using a morpho-kinematical code, the true 3D geometry, from which information such as the remnant's inclination angle and expansion velocity can be derived, of the recurrent nova RS Ophiuchi and classical novae V2491 Cygni, V2672 Ophiuchi and KT Eridani are established and related to other characteristics of each system. Each of the classical novae have also been suggested as a recurrent nova candidate. Furthermore, several enhancements to the modelling code were implemented prompted by the work described in this thesis. The RS Oph work entailed detailed modelling of Hubble Space Telescope resolved imaging combined with ground-based spectroscopic observations. Here it was shown that the bipolar morphology of RS Oph consisted of two distinct components with an outer dumbbell and an inner hour glass overdensity, which were required to reproduce both the observed images and spectra. This morphology was suggested to arise due to the interaction between the pre-existing anisotropic red-giant wind and the ejecta. The observed asymmetry in the ACS/HRC image was shown to be due to the finite width and offset from the [OIII] line's rest wavelength

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

    NASA Astrophysics Data System (ADS)

    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

  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

    SciTech Connect

    Surina, F.; Bode, M. F.; Darnley, M. J.; Harman, D. J.; Hounsell, R. A.; 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 {sub ej} ∼ 4000 km s{sup –1}. A marked drop occurred at t = 5.7 days, and then a gradual increase in derived V {sub ej} to stabilize at ∼1500 km s{sup –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

  1. Nova Scotia.

    ERIC Educational Resources Information Center

    Timmons, Vianne; Power, Anne

    2003-01-01

    This article profiles the educational system of Nova Scotia and discusses initiatives for students who are at-risk. It describes programs and services for students who are at-risk, relevant educational legislation, areas of strength, challenges that need to be overcome, and areas of action. (Contains references.) (CR)

  2. THE 2011 ERUPTION OF THE RECURRENT NOVA T PYXIDIS: THE DISCOVERY, THE PRE-ERUPTION RISE, THE PRE-ERUPTION ORBITAL PERIOD, AND THE REASON FOR THE LONG DELAY

    SciTech Connect

    Schaefer, Bradley E.; Landolt, Arlo U.; Linnolt, Michael; Stubbings, Rod; Pojmanski, Grzegorz; Plummer, Alan; Kerr, Stephen; Nelson, Peter; Carstens, Rolf; Streamer, Margaret; Richards, Tom; Myers, Gordon; Dillon, William G.

    2013-08-10

    We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day{sup -1}, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/ P-dot =+313,000 yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 {+-} 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1}. We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 {+-} 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f{sub {nu}}{proportional_to}{nu}{sup 1.0}, although the narrow ultraviolet region has a tilt with a fit of f{sub {nu}}{proportional_to}{nu}{sup 1/3}. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal

  3. Searching for nova shells around cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Sahman, D. I.; Dhillon, V. S.; Knigge, C.; Marsh, T. R.

    2015-08-01

    We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using H α images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric H α Survey of the Northern Galactic Plane (IPHAS). Both telescopes are located on La Palma. We concentrated our WHT search on nova-like variables, whilst our IPHAS search covered all CVs in the IPHAS footprint. We found one shell out of the 24 nova-like variables we examined. The newly discovered shell is around V1315 Aql and has a radius of ˜2.5 arcmin, indicative of a nova eruption approximately 120 yr ago. This result is consistent with the idea that the high mass-transfer rate exhibited by nova-like variables is due to enhanced irradiation of the secondary by the hot white dwarf following a recent nova eruption. The implications of our observations for the lifetime of the nova-like variable phase are discussed. We also examined four asynchronous polars, but found no new shells around any of them, so we are unable to confirm that a recent nova eruption is the cause of the asynchronicity in the white dwarf spin. We find tentative evidence of a faint shell around the dwarf nova V1363 Cyg. In addition, we find evidence for a light echo around the nova V2275 Cyg, which erupted in 2001, indicative of an earlier nova eruption ˜300 yr ago, making V2275 Cyg a possible recurrent nova.

  4. Magnetic novae

    NASA Astrophysics Data System (ADS)

    Zemko, Polina; Orio, Marina

    2016-07-01

    We present the results of optical and X-ray observations of two quiescent novae, V2491 Cyg and V4743 Sgr. Our observations suggest the intriguing possibility of localization of hydrogen burning in magnetic novae, in which accretion is streamed to the polar caps. V2491 Cyg was observed with Suzaku more than 2 years after the outburst and V4743 Sgr was observed with XMM Newton 2 and 3.5 years after maximum. In the framework of a monitoring program of novae previously observed as super soft X-ray sources we also obtained optical spectra of V4743 Sgr with the SALT telescope 11.5 years after the eruption and of V2491 Cyg with the 6m Big Azimutal Telescope 4 and 7 years post-outburst. In order to confirm the possible white dwarf spin period of V2491 Cyg measured in the Suzaku observations we obtained photometric data using the 90cm WIYN telescope at Kitt Peak and the 1.2 m telescope in Crimea. We found that V4743 Sgr is an intermediate polar (IP) and V2491 Cyg is a strong IP candidate. Both novae show modulation of their X-ray light curves and have X-ray spectra typical of IPs. The Suzaku and XMM Newton exposures revealed that the spectra of both novae have a very soft blackbody-like component with a temperature close to that of the hydrogen burning white dwarfs in their SSS phases, but with flux by at least two orders of magnitude lower, implying a possible shrinking of emitting regions in the thin atmosphere that is heated by nuclear burning underneath it. In quiescent IPs, independently of the burning, an ultrasoft X-ray flux component originates at times in the polar regions irradiated by the accretion column, but the soft component of V4743 Sgr disappeared in 2006, indicating that the origin may be different from accretion. We suggest it may have been due to an atmospheric temperature gradient on the white dwarf surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. The optical spectra of V2491 Cyg and V

  5. Swift-XRT observations of Quasi-periodic oscillations seen in the Super Soft Source emission from Classical and Recurrent Novae

    NASA Astrophysics Data System (ADS)

    Beardmore, Andrew

    2016-07-01

    We report short timescale, soft X-ray flux quasi-periodic oscillations that have been seen by the Swift X-ray Telescope (XRT) during the super soft source (SSS) emission phase from novae. A periodogram analysis revealed oscillations were visible in the 0.3-10 keV XRT light curves obtained from RS Oph (period, P=35.0 s), KT Eri (P=34.9s), V339 Del (P=54.0s), and V5668 Sgr (P=69.7s), with fractional rms variabilities ranging from 1-8 per cent. During day 32-59 of the RS Oph outburst, the oscillation central frequency appeared quite variable, ranging from 26.2-31.1 mHz, caused by a lower coherence at this time. However, after day 50 the oscillation became more coherent, with a frequency that slowly increased from 28.3-28.9 mHz over 9 days, before the trend reversed. The oscillation frequency was less variable in KT Eri and V339 Del. No other correlations, such as between the oscillation frequency or amplitude with source intensity, were seen. A wavelet analysis of the variability seen in RS Oph, KT Eri and V339 Del revealed the oscillations were sometimes visible for entire XRT snapshots lasting 1.0-1.5 ks, yet on other occasions, they were detected for only ˜120 s (i.e. ˜2-4 cycles). The modulation fractional amplitude was variable, occasionally reaching values of 15-20 per cent for a few cycles. During times when the coherence was low, the oscillation phase was seen to jump by ˜0.4-0.6 cycles in RS Oph, then remain stable for ˜10 cycles. KT Eri showed smaller phase jumps of ˜0.2 cycles. We detect a significant spectral variation through the 35s oscillation seen in RS~Oph, with the spectrum becoming harder at the time of the modulation maximum. Fits to the oscillation maximum and minima spectra suggest the increased flux between 0.6-0.75 keV in the former is caused by a 25 per cent reduction in the neutral oxygen column density at this phase. We discuss the possible origins behind the oscillations.

  6. Early-time observations of Type Ia supernovae to reveal progenitors

    NASA Astrophysics Data System (ADS)

    Howell, D. Andrew; Sullivan, Mark; Parrent, Jerod; Nugent, Peter; Hook, Isobel; Dilday, Ben; Maguire, Kate; Graham, Melissa

    2012-02-01

    SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, in a series of three studies this year, our group has placed the first serious constraints on the progenitors of two SNe Ia, finding (1) the first hard evidence that the primary is a CO white dwarf star; (2) in one case the white dwarf is accreting from a mass-losing evolved secondary and has become a recurrent nova like RS Oph; (3) in another case a system like RS Oph is ruled out and the companion is probably a main sequence star. Taken together with our earlier work implicating white dwarfs mergers in the super-Chandra systems, we are led to the remarkable conclusion that there are a multiplicity of progenitors for SNe Ia. This may explain our finding that supernovae in different environments correct to different absolute magnitudes, and could have serious implications for cosmology. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited. We will use these data to rapidly trigger high-resolution searches for circumstellar material at Keck and VLT, and the Gemini data will directly probe the unburned progenitor material in the supernovae themselves.

  7. Novae. Fermi establishes classical novae as a distinct class of gamma-ray sources.

    PubMed

    2014-08-01

    A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in γ rays and stood in contrast to the first γ-ray-detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft-spectrum transient γ-ray sources detected over 2- to 3-week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources. PMID:25082700

  8. EVLA OBSERVATIONS CONSTRAIN THE ENVIRONMENT AND PROGENITOR SYSTEM OF Type Ia SUPERNOVA 2011fe

    SciTech Connect

    Chomiuk, Laura; Soderberg, Alicia M.; Moe, Maxwell; Margutti, Raffaella; Fong, Wen-fai; Dittmann, Jason A.; Chevalier, Roger A.; Rupen, Michael P.; Badenes, Carles; Fransson, Claes

    2012-05-10

    We report unique Expanded Very Large Array observations of SN 2011fe representing the most sensitive radio study of a Type Ia supernova to date. Our data place direct constraints on the density of the surrounding medium at radii {approx}10{sup 15}-10{sup 16} cm, implying an upper limit on the mass loss rate from the progenitor system of M-dot < or approx. 6 x 10{sup -10} M{sub Sun} yr{sup -1} (assuming a wind speed of 100 km s{sup -1}) or expansion into a uniform medium with density n{sub CSM} {approx}< 6 cm{sup -3}. Drawing from the observed properties of non-conservative mass transfer among accreting white dwarfs, we use these limits on the density of the immediate environs to exclude a phase space of possible progenitor systems for SN 2011fe. We rule out a symbiotic progenitor system and also a system characterized by high accretion rate onto the white dwarf that is expected to give rise to optically thick accretion winds. Assuming that a small fraction, 1%, of the mass accreted is lost from the progenitor system, we also eliminate much of the potential progenitor parameter space for white dwarfs hosting recurrent novae or undergoing stable nuclear burning. Therefore, we rule out much of the parameter space associated with popular single degenerate progenitor models for SN 2011fe, leaving a limited phase space largely inhabited by some double degenerate systems, as well as exotic single degenerates with a sufficient time delay between mass accretion and SN explosion.

  9. Properties, evolution and morpho-kinematical modelling of the very fast nova V2672 Oph (Nova Oph 2009), a clone of U Sco

    NASA Astrophysics Data System (ADS)

    Munari, U.; Ribeiro, V. A. R. M.; Bode, M. F.; Saguner, T.

    2011-01-01

    Nova Oph 2009 (V2672 Oph) reached maximum brightness V= 11.35 on 2009 August 16.5. With observed t2(V) = 2.3 and t3(V) = 4.2 d decline times, it is one of the fastest known novae, being rivalled only by V1500 Cyg (1975) and V838 Her (1991) among classical novae, and U Sco among the recurrent ones. The line of sight to the nova passes within a few degrees of the Galactic Centre. The reddening of V2672 Oph is E(B-V) = 1.6 ± 0.1, and its distance d˜ 19 kpc places it on the other side of the Galactic Centre at a galactocentric distance larger than the solar one. The lack of an infrared counterpart for the progenitor excludes the donor star from being a cool giant like in RS Oph or T CrB. With close similarity to U Sco, V2672 Oph displayed a photometric plateau phase, a He/N spectrum classification, extreme expansion velocities and triple peaked emission-line profiles during advanced decline. The full width at zero intensity of Hα was 12 000 km s-1 at maximum, and declined linearly in time with a slope very similar to that observed in U Sco. The properties displayed by V2672 Oph lead us to infer a mass of its white dwarf close to the Chandrasekhar limit and a possible final fate as a Type Ia supernova. Morpho-kinematical modelling of the evolution of the Hα profile suggests that the overall structure of the ejecta is that of a prolate system with polar blobs and an equatorial ring. The density in the prolate system appeared to decline faster than that in the other components. V2672 Oph is seen pole-on, with an inclination of 0°± 6° and an expansion velocity of the polar blobs of 4800+900-800 km s-1. On the basis of its remarkable similarity to U Sco, we suspect this nova may be a recurrent. Given the southern declination, the faintness at maximum, the extremely rapid decline and its close proximity to the ecliptic, it is quite possible that previous outbursts of V2672 Oph have been missed.

  10. Studies of novae at GMRT frequencies

    NASA Astrophysics Data System (ADS)

    Kantharia, N. G.

    2012-09-01

    The Giant Metrewave Radio Telescope (GMRT) which operates at wavelengths longer than 20 cm (frequencies ≤ 1.4 GHz) has been used to search for radio emission from Galactic novae systems since 2002. Of the 11 Galactic novae observed with GMRT, radio continuum emission has been detected in two of the systems whereas atomic gas associated with two systems has been imaged and studied in the 21 cm signal of H I. The two novae studied in the radio continuum with the GMRT are the remnant of GK Persei, a classical nova which had an outburst in 1901 and RS Ophiuchi, a recurrent nova following its last outburst in 2006. Combining the GMRT data on the classical nova GK Persei with VLA data at earlier epochs resulted in concluding that the nova remnant was undergoing a secular decrease in its flux density and in its adiabatic phase of evolution tep{2005A&A...435..167A}. RS Ophiuchi was observed at 1280, 610, 325 and 240 MHz with the GMRT days after its outburst and detected at all the observed frequencies. The near-simultaneous monitoring of its flux density at the low GMRT frequencies, resulted in the study of its spectral index which was indicative of synchrotron emission at all epochs tep{2007ApJ...667L.171K}. A supernova model resulted in a reasonable fit to the observed light curves; in particular the late appearance of emission at the lower GMRT frequencies due to the foreground clumpy, ionized, thermal circumbinary material. Comparison of these results with the previous outburst indicated that the densities of this clumpy medium had reduced making it optically thin to GMRT frequencies in 2006 tep{2007ApJ...667L.171K}. It is important to complement the higher radio frequency studies with observations at GMRT frequencies since these study different regions and physics of the nova system. Studies at GMRT frequencies can result in insights on the shock physics, distribution and density of the circumbinary material or planetary nebula, magnetic field generation and the

  11. High-energy observations of novae

    NASA Astrophysics Data System (ADS)

    Osborne, J.

    2014-07-01

    I will review the lessons learned from the last few years of high-energy observations of classical and recurrent novae. Some observations have reinforced previous ideas (such as ejecta dispersion revealing the hot white dwarf, and ejecta shocks), while others have revealed new behaviours still in the process of being understood. XMM-Newton, Chandra, Swift and Fermi have led the way, MAXI and Suzaku have also contributed. Novae in our own Galaxy can be studied in great detail, and M31 provides a wonderful nova-rich laboratory. The mass of the white dwarf appears to dominate many aspects of nova outbursts, the density of a companion star wind is another significant variable. Even so, there remain very high energy gamma-rays, short period QPOs, and an early soft X-ray phase of huge variability with no obvious correlates or very convincing models.

  12. The UBV Color Evolution of Classical Novae. II. Color-Magnitude Diagram

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2016-04-01

    We have examined the outburst tracks of 40 novae in the color-magnitude diagram (intrinsic B - V color versus absolute V magnitude). After reaching the optical maximum, each nova generally evolves toward blue from the upper right to the lower left and then turns back toward the right. The 40 tracks are categorized into one of six templates: very fast nova V1500 Cyg fast novae V1668 Cyg, V1974 Cyg, and LV Vul moderately fast nova FH Ser and very slow nova PU Vul. These templates are located from the left (blue) to the right (red) in this order, depending on the envelope mass and nova speed class. A bluer nova has a less massive envelope and faster nova speed class. In novae with multiple peaks, the track of the first decay is more red than that of the second (or third) decay, because a large part of the envelope mass had already been ejected during the first peak. Thus, our newly obtained tracks in the color-magnitude diagram provide useful information to understand the physics of classical novae. We also found that the absolute magnitude at the beginning of the nebular phase is almost similar among various novae. We are able to determine the absolute magnitude (or distance modulus) by fitting the track of a target nova to the same classification of a nova with a known distance. This method for determining nova distance has been applied to some recurrent novae, and their distances have been recalculated.

  13. Quark Nova Signatures in Super-luminous Supernovae

    NASA Astrophysics Data System (ADS)

    Kostka, M.; Koning, N.; Leahy, D.; Ouyed, R.; Steffen, W.

    2014-10-01

    Recent observational surveys have uncovered the existence of super-luminous supernovae (SLSNe). In this work we study the light curves of eight SLSNe in the context of dual-shock quark novae. We find that progenitor stars in the range of 25 - 35 M⊙ provide ample energy to power each light curve. An examination into the effects of varying the physical properties of a dual-shock quark nova on light curve composition is undertaken. We conclude that the wide variety of SLSN light curve morphologies can be explained predominantly by variations in the length of time between supernova and quark nova. Our analysis shows that a singular H alpha spectral profile found in three SLSNe can be naturally described in the dual-shock quark nova scenario. Predictions of spectral signatures unique to the dual-shock quark nova are presented.

  14. Typical examples of classical novae

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi; Bianchini, Antonio; Duerbeck, Hilmar W.

    1993-01-01

    Because of the very complicated individualistic behavior of each nova, we think it necessary to review the observations of a few well-observed individuals. We have selected a few objects of different speed classes, which have been extensively observed. They are: V1500 Cygni 1975, a very fast nova; V603 Aql 1918, fast nova; CP Pup 1942, fast nova; GK Per 1901, fast nova; V 1668 Cyg 1979, moderately fast nova; FH Ser 1970, slow nova; DQ Her 1934, slow nova; T Aur 1891, slow nova; RR Pic 1925, slow nova; and HR Del 1967, very slow nova.

  15. Fermi Sees a Nova

    NASA Video Gallery

    Watch V407 Cyg go nova! A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear...

  16. Models for various aspects of dwarf novae and nova-like stars

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    The first attempts to explain the nature of dwarf novae were based on the assumption of single-star phenomena, in which emission lines were assumed to be caused by circumstellar gas shells. The outburst behavior was tentatively ascribed to the kind of (also not understood) mechanism leading to nova outbursts. The realization that some, and possibly all, dwarf novae and nova-like stars (and novae) are binaries eventually led to models which bore more and more similarities to the modern interpretation on the basis of the Roche model. Not all cataclysmic variables are known binaries. In fact, with respect to the entire number of known objects, the proven binaries are still the minority, but all the brightest variables are in fact known to binaries. Not a single system is known which exhibits the usual characteristics of a cataclysmic variable and at the same time can be declared with certainty to be a single star. Two systems are known, the dwarf nova EY Cyg and the recurrent nova V1017 Sgr, in which, in spite of intensive search, no radial velocity variations have been found; but they still exhibit composite spectra consisting of a bright continuum, an emission spectrum, and a cool absorption spectrum. If the Roche model is correct, it is to be expected that a small percentage of objects is viewed pole-on, so orbital motions do not make themselves felt as Doppler shifts of spectral lines. So even these two systems support the hypothesis that all cataclysmic variables (with the possible exception of symbiotic stars) are binaries. In cataclysmic variables, it seems that the brightness changes observed in dwarf novae and nova-like stars in the optical and the UV are due directly to changes in the accretion disks. The study and understanding of accretion disks in these systems can bear potentially valuable consequences for many other fields in astronomy. The observed spectra of dwarf novae and nova-like stars comprise a fairly large range: pure emission spectra, pure

  17. Models for various aspects of dwarf novae and nova-like stars

    NASA Astrophysics Data System (ADS)

    La Dous, Constanze

    1993-09-01

    The first attempts to explain the nature of dwarf novae were based on the assumption of single-star phenomena, in which emission lines were assumed to be caused by circumstellar gas shells. The outburst behavior was tentatively ascribed to the kind of (also not understood) mechanism leading to nova outbursts. The realization that some, and possibly all, dwarf novae and nova-like stars (and novae) are binaries eventually led to models which bore more and more similarities to the modern interpretation on the basis of the Roche model. Not all cataclysmic variables are known binaries. In fact, with respect to the entire number of known objects, the proven binaries are still the minority, but all the brightest variables are in fact known to binaries. Not a single system is known which exhibits the usual characteristics of a cataclysmic variable and at the same time can be declared with certainty to be a single star. Two systems are known, the dwarf nova EY Cyg and the recurrent nova V1017 Sgr, in which, in spite of intensive search, no radial velocity variations have been found; but they still exhibit composite spectra consisting of a bright continuum, an emission spectrum, and a cool absorption spectrum. If the Roche model is correct, it is to be expected that a small percentage of objects is viewed pole-on, so orbital motions do not make themselves felt as Doppler shifts of spectral lines. So even these two systems support the hypothesis that all cataclysmic variables (with the possible exception of symbiotic stars) are binaries. In cataclysmic variables, it seems that the brightness changes observed in dwarf novae and nova-like stars in the optical and the UV are due directly to changes in the accretion disks. The study and understanding of accretion disks in these systems can bear potentially valuable consequences for many other fields in astronomy. The observed spectra of dwarf novae and nova-like stars comprise a fairly large range: pure emission spectra, pure

  18. NOVA 201 ultrasonic thickness gage (NOVA Gage)

    NASA Technical Reports Server (NTRS)

    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.

  19. Novae as distance indicators

    NASA Technical Reports Server (NTRS)

    Ford, Holland C.; Ciardullo, Robin

    1988-01-01

    Nova shells are characteristically prolate with equatorial bands and polar caps. Failure to account for the geometry can lead to large errors in expansion parallaxes for individual novae. When simple prescriptions are used for deriving expansion parallaxes from an ensemble of randomly oriented prolate spheroids, the average distance will be too small by factors of 10 to 15 percent. The absolute magnitudes of the novae will be underestimated and the resulting distance scale will be too small by the same factors. If observations of partially resolved nova shells select for large inclinations, the systematic error in the resulting distance scale could easily be 20 to 30 percent. Extinction by dust in the bulge of M31 may broaden and shift the intrinsic distribution of maximum nova magnitudes versus decay rates. We investigated this possibility by projecting Arp's and Rosino's novae onto a composite B - 6200A color map of M31's bulge. Thirty two of the 86 novae projected onto a smooth background with no underlying structure due to the presence of a dust cloud along the line of sight. The distribution of maximum magnitudes versus fade rates for these unreddened novae is indistinguishable from the distribution for the entire set of novae. It is concluded that novae suffer very little extinction from the filamentary and patchy distribution of dust seen in the bulge of M31. Time average B and H alpha nova luminosity functions are potentially powerful new ways to use novae as standard candles. Modern CCD observations and the photographic light curves of M31 novae found during the last 60 years were analyzed to show that these functions are power laws. Consequently, unless the eruption times for novae are known, the data cannot be used to obtain distances.

  20. A Decade of Progress in Understanding the Eruptions of Classical Novae

    NASA Astrophysics Data System (ADS)

    Shara, M. M.

    2014-12-01

    During the 11 years since the 2002 Sitges Nova conference, over 700 refereed papers dealing with classical novae have been published. Rather than spend 2.3 seconds reviewing each one, I've tried to focus on the main themes that have captured the interests of most researchers. I've also used, as examples, the most influential and cited papers in each subfield, though a decade from now some of my choices may seem dated, provincial, or flat-out wrong. The key topics that I address include theory and simulations of nova explosions; the recurrent novae; observations of ejecta; symbiotic novae; connections between novae and type Ia supernovae; connections between classical and dwarf novae; extragalactic novae; the maximum magnitude - rate of decline relationship; and a set of challenges and unanswered questions that I hope we will have made much progress on by the time we reassemble around 2024.

  1. Near-infrared studies during maximum and early decline of Nova Cephei 2014 and Nova Scorpii 2015

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We present multiepoch near-infrared photospectroscopic 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 C I, H I and O I lines, whereas Nova Sco 2015 is shown to belong to the He/N class with strong He I, H I and O I 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 threefold; 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 α excess seen from the system and third is the spectral energy distribution of the secondary in quiescence typical of a cool late-type giant. The evolution of the strength and shape of the emission line profiles shows that the ejecta velocity follows a power-law decay with time (t-1.13±0.17). A Case B recombination analysis of the H I Brackett lines shows that these lines are affected by optical depth effects for both the novae. Using this analysis, we make estimates for both the novae of the emission measure n_e^2L, the electron density ne and the mass of the ejecta.

  2. The First Nova Explosions

    NASA Astrophysics Data System (ADS)

    José, Jordi; García-Berro, Enrique; Hernanz, Margarita; Gil-Pons, Pilar

    2007-06-01

    Classical novae are stellar explosions with an energy release that is only overcome by supernovae and γ-ray bursts. Theoretical and observational evidence suggests that these cataclysmic events are major sources of the Galactic 15N, 17O, and 13C, and contribute to the abundances of 7Li, and 26Al, with a likely nucleosynthetic endpoint around Ca. However, there are reasons to believe that these nuclear signatures have changed during the overall Galactic history. In this Letter, the first that addresses the nature of nova explosions in the most primitive, low-metallicity binaries, we show that primordial novae eject more massive envelopes and display a larger nuclear activity than classical novae, leading to a new type of explosion, halfway between a supernova and a nova. The ejected shells from the most violent, massive primordial novae yield large excesses of Ti and a likely nucleosynthetic endpoint around Cu-Zn, signatures never before associated with a nova-like explosion. We conclude that the chemical abundance pattern of the nova ejecta is strongly modified at low metallicities and suggest that primordial novae are a possible birthplace of a rare variety of presolar grains whose origin remains uncertain.

  3. Progenitor Epithelium

    PubMed Central

    Marty-Santos, Leilani

    2015-01-01

    Insulin-producing β cells within the vertebrate fetal pancreas acquire their fate in a step-wise manner. Whereas the intrinsic factors dictating the transcriptional or epigenetic status of pancreatic lineages have been intensely examined, less is known about cell–cell interactions that might constitute a niche for the developing β cell lineage. It is becoming increasingly clear that understanding and recapitulating these steps may instruct in vitro differentiation of embryonic stem cells and/or therapeutic regeneration. Indeed, directed differentiation techniques have improved since transitioning from 2D to 3D cultures, suggesting that the 3D microenvironment in which β cells are born is critical. However, to date, it remains unknown whether the changing architecture of the pancreatic epithelium impacts the fate of cells therein. An emerging challenge in the field is to elucidate how progenitors are allocated during key events, such as the stratification and subsequent resolution of the pre-pancreatic epithelium, as well as the formation of lumens and branches. Here, we assess the progenitor epithelium and examine how it might influence the emergence of pancreatic multipotent progenitors (MPCs), which give rise to β cells and other pancreatic lineages. PMID:26216134

  4. Nova-like variables

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    On grounds of different observable characteristics five classes of nova-like objects are distinguished: the UX Ursae Majoris stars, the antidwarf novae, the DQ Herculis stars, the AM Herculis stars, and the AM Canum Venaticorum stars. Some objects have not been classified specifically. Nova-like stars share most observable features with dwarf novae, except for the outburst behavior. The understanding is that dwarf novae, UX Ursae Majoris stars, and anti-dwarf novae are basically the same sort of objects. The difference between them is that in UX Ursae Majoris stars the mass transfer through the accretion disc always is high so the disc is stationary all the time; in anti-dwarf novae for some reason the mass transfer occasionally drops considerably for some time, and in dwarf novae it is low enough for the disc to undergo semiperiodic changes between high and low accretion events. DQ Herculis stars are believed to possess weakly magnetic white dwarfs which disrupt the inner disc at some distance from the central star; the rotation of the white dwarf can be seen as an additional photometric period. In AM Herculis stars, a strongly magnetic white dwarf entirely prevents the formation of an accretion disk and at the same time locks the rotation of the white dwarf to the binary orbit. Finally, AM Canum Venaticorum stars are believed to be cataclysmic variables that consist of two white dwarf components.

  5. Novae in globular clusters

    SciTech Connect

    Kato, Mariko; Hachisu, Izumi; Henze, Martin

    2013-12-10

    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 {sub ☉} for M31N 2007-06b in Bol 111 and about 1.37 M {sub ☉} 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 {sub ☉} 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.

  6. NOVA, A BRIEF .....

    ERIC Educational Resources Information Center

    WHITING, RICHARD; AND OTHERS

    NOVA IS AN EXPERIMENTAL, 6-YEAR JUNIOR-SENIOR HIGH SCHOOL. ASPECTS OF THE PROGRAM INCLUDE THE TRIMESTER SYSTEM, THE CONTINUOUS PROGRESS CURRICULUM, TEAM TEACHING, A CLASS SCHEDULE OF FOUR 70-MINUTE PERIODS PER WEEK, THE USE OF DATA-PROCESSING EQUIPMENT, AND MODERN INSTRUCTIONAL AIDS. NOVA IS ORGANIZED CAMPUS-STYLE WITH INDIVIDUAL BUILDINGS DEVOTED…

  7. Nucleosynthesis in classical novae

    NASA Astrophysics Data System (ADS)

    José, Jordi; Hernanz, Margarita; Iliadis, Christian

    2006-10-01

    Classical novae are dramatic stellar explosions with an energy release that is only overcome by supernovae and gamma-ray bursts. These unique cataclysmic events constitute a crucible where different scientific disciplines merge, including astrophysics, nuclear and atomic physics, cosmochemistry, high-energy physics or computer science. In this review, we focus on the nucleosynthesis accompanying nova outbursts. Theoretical predictions are compared with the elemental abundances inferred from observations of the nova ejecta as well as with the isotopic abundance ratios measured in meteorites. Special emphasis is given to the interplay between nova outbursts and the Galactic abundance pattern and on the synthesis of radioactive nuclei for which γ-ray signals are expected. Finally, we analyze the key role played by nuclear physics in our understanding of the nova phenomenon by means of recent experiments and a thorough account of the impact of nuclear uncertainties.

  8. The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M 31 nova catalogue

    NASA Astrophysics Data System (ADS)

    Lee, C.-H.; Riffeser, A.; Seitz, S.; Bender, R.; Fliri, J.; Hopp, U.; Ries, C.; Bärnbantner, O.; Gössl, C.

    2012-01-01

    We present light curves from the novae detected in the long-term, M 31-monitoring WeCAPP project. The goal of WeCAPP is to constrain the compact dark matter fraction of the M 31 halo with microlensing observations. As a by product we detected 91 novae benefiting from the high cadence and highly sensitive difference imaging technique required for pixel-lensing. We thus can now present the largest sample of optical/CCD nova lightcurves towards M 31 to date. We also obtained thorough coverage of the light curve before and after the eruption thanks to the long-term monitoring. We apply a nova taxonomy to our nova candidates and found 29 S-class novae, 10 C-class novae, 2 O-class novae, and 1 J-class nova. We investigated a universal decline law on the S-class novae. In addition, we correlated our catalogue with the literature and found 4 potential recurrent novae. Part of our catalogue has been used to search for optical counterparts of the super soft X-ray sources detected in M 31. Optical surveys like WeCAPP, when coordinated with multi-wavelength observation, will continue to shed light on the underlying physical mechanism of novae in the future.

  9. Getting to know classical novae with Swift

    NASA Astrophysics Data System (ADS)

    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.

  10. ON THE NATURE OF THE PROGENITOR OF THE Type Ia SN2011fe IN M101

    SciTech Connect

    Liu Jifeng; Di Stefano, Rosanne; Wang Tao; Moe, Maxwell

    2012-04-20

    The explosion of a Type Ia supernova, SN2011fe, in the nearby Pinwheel galaxy (M101 at 6.4 Mpc) provides an opportunity to study pre-explosion images and search for the progenitor, which should consist of a white dwarf (WD), possibly surrounded by an accretion disk, in orbit with another star. We report on our use of deep Chandra observations and Hubble Space Telescope observations to limit the luminosity and temperature of the pre-explosion WD. It is found that if the spectrum was a blackbody, then pre-SN WDs with steady nuclear burning of the highest possible temperatures and luminosities are excluded assuming moderate n{sub H} values, but values of kT between roughly 10 eV and 60 eV are permitted even if the WD was emitting at the Eddington luminosity. This allows the progenitor to be an accreting nuclear-burning WD with an expanded photosphere 4-100 times the WD itself, or a super-critically accreting WD blowing off an optically thick strong wind, or possibly a recurrent nova with luminosities an order of magnitude lower than Eddington. The observations are also consistent with a double degenerate scenario, or a spinning down WD that has been spun up by accretion from the donor.

  11. Distribution of novae and supernova remnants in the Large Magellanic Cloud

    SciTech Connect

    Van den Bergh, S.

    1988-12-01

    Novae in the LMC appear to be distributred like an old disk population. The fact that no concentration of novae is seen within the Bar of the Large Cloud suggests that this feature is of relatively recent origin. Supernova remnants are seen to exhibit concentrations in the 30 Dor region, in the Bar of the Large Cloud, and in Constellation III. This distribution supports the idea that most of the supernova remnants in the LMC had young massive progenitors. 11 references.

  12. Studies of Novae in the 20th Century

    NASA Astrophysics Data System (ADS)

    Starrfield, Sumner

    2002-11-01

    A nova outburst is not only the third most violent explosion that can occur in a galaxy, it is the largest hydrogen bomb in the Universe. The last meeting devoted purely to studies of novae was held in Madrid in 1989. At that time IUE spectra of novae were just beginning to be analyzed in detail, the EXOSAT x-ray results had just been published, and ROSAT had yet to be launched. Since that time, the IUE studies of novae in the LMC (known distance and small reddening) showed that all fast novae exceed the Eddington luminosity at maximum which was not predicted by numerical hydrodynamic simulations. A number of novae have now been observed in x-rays with ROSAT, BEPPOSAX, ASCA, CHANDRA, and XMM (plus others). The x-ray studies determined the turn off times for several classical novae, showed that at maximum x-ray light they resemble the Super Soft Sources, and found rapid variations in the x-ray light curves of two novae. There have been abundance analyses of V838 Her (oxygen poor, sulfur rich), LMC 1991, and other classical and recurrent novae. Infrared studies have resulted in a number of puzzling results such as the same nova producing both carbon (first) and silicate (later) dust at different times during its outburst. There have been advances in theoretical modeling and most studies now include large nuclear reaction networks combined with the hydrodynamic calculations. One perplexing problem produced by the simulations is that they predict that much less mass is ejected in the outburst than is observed, and the problem has worsened as the input physics has improved. Nevertheless we have made significant progress in the past 100 years and I will present some of the more important developments that have occurred over the past century. I will end with a list of questions to be answered.

  13. Light echoes - Novae

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1988-01-01

    The sudden brilliance of a nova eruption will be reflected on surrounding dust grains to create a phantom nebula. Previous searches for these light echoes have used relatively short exposures with photograhic detectors. This paper reports on a search around eight recent novae with long exposures using a CCD camera. Despite an increase of sensitivity by over an order of magnitude, no light echoes were detected. It is found that the average grain density must be less than about 10 to the -9th per cu cm for distances from 0.1 pc to 1000 pc from the novae. The light echo around Nova Persei 1901 was caused by reflection off clouds with grain densities of several times 10 to the -9th per cu cm which are at distances between 0.1 pc and 10 pc. Echoes from dust in a circumstellar shell or ejected during a previous eruption will be effectively unobservable.

  14. OGLE Atlas of Classical Novae. II. Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Mróz, P.; Udalski, A.; Poleski, R.; Soszyński, I.; Szymański, M. K.; Pietrzyński, G.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Pietrukowicz, P.; Skowron, J.

    2016-01-01

    The population of classical novae in the Magellanic Clouds was poorly known because of a lack of systematic studies. There were some suggestions that nova rates per unit mass in the Magellanic Clouds were higher than in any other galaxy. Here, we present an analysis of data collected over 16 years by the OGLE survey with the aim of characterizing the nova population in the Clouds. We found 20 eruptions of novae, half of which are new discoveries. We robustly measure nova rates of 2.4 ± 0.8 yr-1 (LMC) and 0.9 ± 0.4 yr-1 (SMC) and confirm that the K-band luminosity-specific nova rates in both Clouds are 2-3 times higher than in other galaxies. This can be explained by the star formation history in the Magellanic Clouds, specifically the re-ignition of the star formation rate a few Gyr ago. We also present the discovery of the intriguing system OGLE-MBR133.25.1160, which mimics recurrent nova eruptions.

  15. Synthesis of C-rich dust in CO nova outbursts

    NASA Astrophysics Data System (ADS)

    José, Jordi; Halabi, Ghina M.; El Eid, Mounib F.

    2016-09-01

    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 these outbursts, about 10-7-10-3 M⊙, 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, in principle, only oxidized condensates (e.g., O-rich grains) would be expected. Methods: To specifically address whether CO novae can actually produce C-rich dust, six different hydrodynamic nova models have been evolved, from accretion to the expansion and ejection stages, with different choices for the composition of the substrate with which the solar-like accreted material mixes. Updated chemical profiles inside the H-exhausted core have been used, based on stellar evolution calculations for a progenitor of 8 M⊙ through H- and He-burning phases. Results: We show that these profiles lead to C-rich ejecta after the nova outburst. This extends the possible contribution of novae to the inventory of presolar grains identified in meteorites, particularly in a number of carbonaceous phases (i.e., nanodiamonds, silicon carbides, and graphites).

  16. THE PROGENITOR OF THE TYPE Ia SUPERNOVA THAT CREATED SNR 0519-69.0 IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Edwards, Zachary I.; Pagnotta, Ashley; Schaefer, Bradley E.

    2012-03-10

    Models for the progenitor systems of Type Ia supernovae can be divided into double-degenerate systems, which contain two white dwarfs, and single-degenerate systems, which contain one white dwarf plus one companion star (either a red giant, a subgiant, or a >1.16 M{sub Sun} main-sequence star). The white dwarf is destroyed in the supernova explosion, but any non-degenerate companion remains intact. We present the results of a search for an ex-companion star in SNR 0519-69.0, located in the Large Magellanic Cloud, based on images taken with the Hubble Space Telescope with a limiting magnitude of V = 26.05. SNR 0519-69.0 is confidently known to be from a Type Ia supernova based on its light echoes and X-ray spectra. The geometric center of the remnant (based on the H{alpha} and X-ray shell) is at 05:19:34.83, -69:02:06.92 (J2000). Accounting for the measurement uncertainties, the orbital velocity, and the kick velocity, any ex-companion star must be within 4.''7 of this position at the 99.73% confidence level. This circle contains 27 main-sequence stars brighter than V = 22.7, any one of which could be the ex-companion star left over from a supersoft source progenitor system. The circle contains no post-main-sequence stars, and this rules out the possibility of all other published single-degenerate progenitor classes (including symbiotic stars, recurrent novae, helium donors, and the spin-up/spin-down models) for this particular supernova. The only remaining possibility is that SNR 0519-69.0 was formed from either a supersoft source or a double-degenerate progenitor system.

  17. Is the Nova V2672 Oph a Luminous X-ray Source in Quiescence?

    NASA Astrophysics Data System (ADS)

    Mukai, Koji

    2014-09-01

    The very fast nova V2672 Oph had one of the shortest decay times (t2=2.3 d) and the broadest emission lines (FWZI up to 12,000 km/s) ever observed in novae. It may well be a recurrent nova with a near Chandrasekhar mass white dwarf. There is also a ROSAT all-sky survey Faint Source Catalog source consistent with its position: if confirmed, V2672 Oph would be only the third nova to have been detected in X-rays before the nova eruption. We therefore propose an ACIS-S imaging observation to provide the precise location, and rough timing and spectral characteristics of the ROSAT source. V2672 Oph may join V2487 Oph and V2491 Cyg as novae with quiescent X-ray luminosities not seen in normal cataclysmic variables.

  18. The impact of IUE on studies of the nova outburst: 1986--1990

    SciTech Connect

    Starrfield, S. . Dept. of Physics Los Alamos National Lab., NM )

    1990-01-01

    In this review I will concentrate on the improvements in our understanding of the nova outburst that have occurred since the IUE meetings in London in 1986 and Goddard in 1988 and those results that have occurred as a direct result of studies with the IUE satellite. These involve the four outbursts that have occurred in the LMC, the numerous recurrent novae outbursts, and a number of archival studies. As a direct result of IUE studies done since 1986, we can now state that fast novae become super-Eddington at maximum, that many novae decline at the same rate, and that neon novae may be more numerous than thought previously. In addition, we have found that there are differences in the outburst characteristics between novae with giant secondaries and those with compact secondaries. 18 refs., 11 figs., 1 tab.

  19. Quark-Nova

    NASA Astrophysics Data System (ADS)

    Ouyed, R.; Dey, J.; Dey, M.

    2002-07-01

    We explore the scenario where the core of a neutron star (having experienced a transition to an up and down quark phase) shrinks into the equilibrated quark object after reaching strange quark matter saturation density (where a composition of up, down and strange quarks is the favored state of matter). The overlaying (envelope) material free-falls following the core contraction releasing upto 1053 ergs in energy as radiation, partly as a result of the conversion of envelope material to quarks. This phenomena, we named Quark-Nova, leads to a wide variety of ejectae ranging form the Newtonian, ``dirty" to the ultra-relativistic fireball. The mass range of the corresponding compact remnant (the quark star) ranges from less than 0.3 Msun up to a solar mass. We discuss the connection between Quark-Novae and Gamma ray bursts and suggest the recently studied GRB011211 event as a plausible Quark-Nova candidate.

  20. Observations of Novae From ROAD

    NASA Astrophysics Data System (ADS)

    Hambsch, F.-J.

    2014-12-01

    The author discusses observations of galactic novae and some extragalactic supernovae from his remote observatory ROAD (Remote Observatory Atacama Desert) he commenced in August 2011 with Nova Lupi 2011 (PR Lup). The observed novae are mainly chosen according to AAVSO Alert Notices and AAVSO Special Notices as published on their website. Examples of dense observations of different novae are presented. The focus goes to the different behaviors of their light curves. It also demonstrates the capability of the remote observatory ROAD.

  1. Observations of Novae from ROAD

    NASA Astrophysics Data System (ADS)

    Hambsch, Franz-Josef

    2014-05-01

    The author discusses observations of galactic novae and some extragalactic supernovae from his remote observatory ROAD (Remote Observatory Atacama Desert) he commenced in August 2011 with Nova Lupi 2011 (PR Lup). The observed novae are mainly chosen according to alert notices and special notices of the AAVSO as published on their website. Examples of dense observations of different novae are presented. The focus goes to the different behaviors of their light curves. It also demonstrates the capability of the remote observatory ROAD.

  2. Precision Nova operations

    SciTech Connect

    Ehrlich, R.B.; Miller, J.L.; Saunders, R.L.; Thompson, C.E.; Weiland, T.L.; Laumann, C.W.

    1995-09-01

    To improve the symmetry of x-ray drive on indirectly driven ICF capsules, we have increased the accuracy of operating procedures and diagnostics on the Nova laser. Precision Nova operations includes routine precision power balance to within 10% rms in the ``foot`` and 5% nns in the peak of shaped pulses, beam synchronization to within 10 ps rms, and pointing of the beams onto targets to within 35 {mu}m rms. We have also added a ``fail-safe chirp`` system to avoid Stimulated Brillouin Scattering (SBS) in optical components during high energy shots.

  3. Novae as a Class of Transient X-ray Sources

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Orio, M.; Valle, M. Della

    2007-01-01

    Motivated by the recently discovered class of faint (10(exp 34)-10(exp 35) ergs/s) X-ray transients in the Galactic Center region, we investigate the 2-10 keV properties of classical and recurrent novae. Existing data are consistent with the idea that all classical novae are transient X-ray sources with durations of months to years and peak luminosities in the 10(exp 34)-10(exp 35)ergs/s range. This makes classical novae a viable candidate class for the faint Galactic Center transients. We estimate the rate of classical novae within a 15 arcmin radius region centered on the Galactic Center (roughly the field of view of XMM-Newton observations centered on Sgr A*) to be approx.0.1 per year. Therefore, it is plausible that some of the Galactic Center transients that have been announced to date are unrecognized classical novae. The continuing monitoring of the Galactic Center region carried out by Chandra and XMM-Newton may therefore provide a new method to detect classical novae in this crowded and obscured region, an

  4. THE BEHAVIOR OF NOVAE LIGHT CURVES BEFORE ERUPTION

    SciTech Connect

    Collazzi, Andrew C.; Schaefer, Bradley E.; Xiao Limin; Pagnotta, Ashley; Kroll, Peter; Loechel, Klaus; Henden, Arne A.

    2009-12-15

    In 1975, E. R. Robinson conducted the hallmark study of the behavior of classical nova light curves before eruption, and this work has now become part of the standard knowledge of novae. He made three points: 5 out of 11 novae showed pre-eruption rises in the years before eruption, one nova (V446 Her) showed drastic changes in the variability across eruptions, and all but one of the novae (excepting BT Mon) have the same quiescent magnitudes before and after the outburst. This work has not been tested since it came out. We have now tested these results by going back to the original archival photographic plates and measuring large numbers of pre-eruption magnitudes for many novae using comparison stars on a modern magnitude scale. We find in particular that four out of five claimed pre-eruption rises are due to simple mistakes in the old literature, that V446 Her has the same amplitude of variations across its 1960 eruption, and that BT Mon has essentially unchanged brightness across its 1939 eruption. Out of 22 nova eruptions, we find two confirmed cases of significant pre-eruption rises (for V533 Her and V1500 Cyg), while T CrB has a deep pre-eruption dip. These events are a challenge to theorists. We find no significant cases of changes in variability across 27 nova eruptions beyond what is expected due to the usual fluctuations seen in novae away from eruptions. For 30 classical novae plus 19 eruptions from 6 recurrent novae, we find that the average change in magnitude from before the eruption to long after the eruption is 0.0 mag. However, we do find five novae (V723 Cas, V1500 Cyg, V1974 Cyg, V4633 Sgr, and RW UMi) that have significantly large changes, in that the post-eruption quiescent brightness level is over ten times brighter than the pre-eruption level. These large post-eruption brightenings are another challenge to theorists.

  5. X-ray Observations of Novae with Swift

    NASA Astrophysics Data System (ADS)

    Page, Kim

    2016-07-01

    The rapid response capabilities of the Swift satellite, together with the daily planning of its observing schedule, make it an ideal mission for following novae in the X-ray and UV bands, particularly during their early phases of rapid evolution. A number of both classical and recurrent novae have been extensively monitored by Swift throughout their super-soft phase and later decline. We report results from these observations, including the high-amplitude flux variation often see at the start of the super-soft emission, the differing relationships between the X-ray and UV variability, and the spectral evolution seen in the X-ray band.

  6. SCIENCE AT NOVA.

    ERIC Educational Resources Information Center

    Broward County Schools, Fort Lauderdale, FL.

    THE SCIENCE PROGRAM AT NOVA HIGH SCHOOL IS STRUCTURED TO MEET THE NEEDS OF A SCIENTIFIC SOCIETY. THE JUNIOR HIGH PROGRAM EMPHASIZES THE ACCUMLATION, TABULATION, AND ANALYSIS OF DATA. THE SENIOR HIGH PROGRAM MAKES USE OF THESE PROCESSES IN THE INVESTIGATION OF VARIOUS SUBJECT AREAS. THE UNITS COMPOSING THE HIGH SCHOOL CURRICULUM ARE DESCRIBED. UNIT…

  7. Progenitors of type Ia supernovae in elliptical galaxies

    SciTech Connect

    Gilfanov, M.; Bogdan, A.

    2011-09-21

    Although there is a nearly universal agreement that type Ia supernovae are associated with the thermonuclear disruption of a CO white dwarf, the exact nature of their progenitors is still unknown. The single degenerate scenario envisages a white dwarf accreting matter from a non-degenerate companion in a binary system. Nuclear energy of the accreted matter is released in the form of electromagnetic radiation or gives rise to numerous classical nova explosions prior to the supernova event. We show that combined X-ray output of supernova progenitors and statistics of classical novae predicted in the single degenerate scenario are inconsistent with X-ray and optical observations of nearby early type galaxies and galaxy bulges. White dwarfs accreting from a donor star in a binary system and detonating at the Chandrasekhar mass limit can account for no more than {approx}5% of type Ia supernovae observed in old stellar populations.

  8. A Renaissance in Studies of Novae

    NASA Astrophysics Data System (ADS)

    Starrfield, Sumner

    2010-03-01

    Classical and Recurrent Novae (CNe and RNe) outbursts are the most common of the explosions in a galaxy. They have been observed as close as a kpc and as far as M87. In a nova, material is accreted from a Roche-lobe filling star and accumulates on a white dwarf until an explosion occurs. Accreted material is mixed with white dwarf core material at some time during the evolution of the explosion. The mixture is processed through hot hydrogen burning before being ejected into space and analyzing the ejecta allows us to determine the core composition of the white dwarf. CNe are one component in the cycle of Galactic chemical evolution where the ejected metal-enriched gas is a source of nuclei for the ISM. IR observations show that some CNe form multiple types of grains in their ejecta which may have been identified in meteoritic material. Simulations predict, and observations confirm, that there is a phase of X-ray emission from the post-explosion hot white dwarf emitted by the accreted plus core layers that were not initially ejected. The hot photosphere is revealed as the ejection phase ends. We will report on the recent renaissance in studies of RNe and CNe with Swift, Chandra, XMM, RXTE, HST, and Spitzer, as well as recent advances in the theory of the outburst. These new results question some long held beliefs about novae and provided evidence for a possible connection between novae, the Super Soft Binary X-ray sources, and SN Ia. I acknowledge partial support from Chandra, Swift, Spitzer, NASA Theory and the NSF.

  9. CLASSICAL NOVAE IN ANDROMEDA: LIGHT CURVES FROM THE PALOMAR TRANSIENT FACTORY AND GALEX

    SciTech Connect

    Cao Yi; Lou Yuqing; Kasliwal, Mansi M.; Neill, James D.; Kulkarni, S. R.; Quimby, Robert M.; Ben-Ami, Sagi; Bloom, Joshua S.; Cenko, S. Bradley; Nugent, Peter E.; Law, Nicholas M.; Ofek, Eran O.; Poznanski, Dovi

    2012-06-20

    We present optical light curves of 29 novae in M31 during the 2009 and 2010 observing seasons of the Palomar Transient Factory (PTF). The dynamic and rapid cadences in PTF monitoring of M31, from one day to ten minutes, provide excellent temporal coverage of nova light curves, enabling us to record the photometric evolution of M31 novae in unprecedented detail. We also detect eight of these novae in the near-ultraviolet (UV) band with the Galaxy Evolution Explorer (GALEX) satellite. Novae M31N 2009-10b and M31N 2010-11a show prominent UV emission peaking a few days prior to their optical maxima, possibly implying aspherical outbursts. Additionally, our blueshifted spectrum of the recent outburst of PT And (M31N 2010-12a) indicates that it is a recurrent nova in M31 and not a dwarf nova in the Milky Way as was previously assumed. Finally, we systematically searched for novae in all confirmed globular clusters (GCs) of M31 and found only M31N 2010-10f associated with Bol 126. The specific nova rate in the M31 GC system is thus about one per year, which is not enhanced relative to the rate outside the GC system.

  10. Nova Scorpii 2008

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2008-09-01

    Nova Sco 2008 was discovered by K. Nishiyama, Kurume, Fukuoka-ken, Japan, and F. Kabashima, Miyaki-cho, Saga-ken, Japan; Y. Sakurai, Mito, Ibaraki-ken, Japan; and Guoyou Sun, Qufu, Shandong, China, and Xing Gao, Urumqi, Xinjiang, China, on 2008 September 02.4594 UTC at magnitude 9.5 (unfiltered). This is a classical nova, as determined by low-resolution spectra by M. Fujii, Ibara, Okayama, Japan, and by H. Naito, Nishi-Harima Astron. Obs., on Sept 3.49 and Sept 5.47 UT, respectively. This object has been given the formal variable star designation V1309 Sco. Discovery information is from IAU Circular 8972, Daniel W.E. Green, editor. Observations should be submitted to the AAVSO International Database as V1309 SCO.

  11. Fermi Establishes Classical Novae as a Distinct Class of Gamma-ray Sources

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet, J.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Ferrara, E. C.; Harding, A. K.; Hays, E.; Perkins, J. S.; Thompson, D. J.

    2014-01-01

    A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in gamma rays and stood in contrast to the first gamma-ray detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft spectrum transient gamma-ray sources detected over 2-3 week durations. The gamma-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic gamma-ray sources.

  12. Working Together to Understand Novae

    NASA Astrophysics Data System (ADS)

    Sokoloski, J.

    2013-06-01

    (Abstract only) In ancient times, people occasionally looked up to find a "nova," or new star, in the sky. With at least thirty-five per year in our galaxy, novae are the most common major stellar explosions. Although researchers now understand what causes a white dwarf to suddenly brighten into a nova, many puzzles remain, such as why novae appear to eject orders of magnitude more material than predicted by theory, and how a uniform eruption on a spherical white dwarf can expel matter in the form of jets, clumps, and rings. Coordinated observations at radio, optical, and X-ray wavelengths can answer these questions. I will describe how the AAVSO's new nova forum (http://www.aavso.org/forums/variable-stars/nova-project) is designed to enhance communication between amateur astronomers and professional astronomers who are using X-ray and newly upgraded radio telescopes to observe novae. Participants in the nova forum will have the opportunity to learn about novae, share their own expertise, and be a part of the process of scientific discovery.

  13. The Thermonuclear Runaway and the Classical Nova Outburst

    NASA Astrophysics Data System (ADS)

    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.

  14. Nova in Eridanus (KT Eri = N Eri 2009)

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2009-12-01

    The discovery is reported of Nova Eri 2009 = KT Eri by K. Itagaki, Yamagata, Japan, on Nov. 25.536 UT at unfiltered CCD magnitude 8.1. Spectra from several sources indicates KT Eri is a He/N nova. Pre-discovery images indicate KT Eri actually reached 5th magnitude, and the apparent progenitor is relatively bright at 15th magnitude. Initially announced in CBET 2050 (Daniel W. E. Green, ed.) and AAVSO Special Notice #181 (Elizabeth O. Waagen), with additional information in Special Notices #182 (Arne A. Henden) and #183 (Henden) and CBETs 2053 and 2055 (Daniel W. E. Green, ed.). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  15. Recurrent varicocele

    PubMed Central

    Rotker, Katherine; Sigman, Mark

    2016-01-01

    Varicocele recurrence is one of the most common complications associated with varicocele repair. A systematic review was performed to evaluate varicocele recurrence rates, anatomic causes of recurrence, and methods of management of recurrent varicoceles. The PubMed database was evaluated using keywords “recurrent” and “varicocele” as well as MESH criteria “recurrent” and “varicocele.” Articles were not included that were not in English, represented single case reports, focused solely on subclinical varicocele, or focused solely on a pediatric population (age <18). Rates of recurrence vary with the technique of varicocele repair from 0% to 35%. Anatomy of recurrence can be defined by venography. Management of varicocele recurrence can be surgical or via embolization. PMID:26806078

  16. HET Spectroscopy of Extragalactic Novae

    NASA Astrophysics Data System (ADS)

    Shafter, Allen W.; Coelho, E. A.; Misselt, K. A.; Bode, M. F.; Darnley, M. J.

    2006-12-01

    We are currently involved in a multifaceted campaign to study extragalactic novae in the optical and IR using a variety of instruments: The Mount Laguna 1m, the Steward 2.3m, and the Liverpool 2m telescopes for optical imaging, the Hobbey-Eberly Telescope (HET) for optical spectroscopy, and the Spitzer Space Telescope for IR photometry and spectroscopy. Here, we report the initial results from our program of spectroscopic observations obtained with the LRS on the HET. Thus far, we have obtained spectra of three novae: Nova M31-2006#9 (ATEL 887), Nova M32-2006#1 (CBET 591), and Nova M33-2006#1 (CBET 655), which were taken on 24-Sep-2006 UT, 30-Sep-2006 UT, and 02-Oct-2006 UT, approximately 6, 65, and 4 days post discovery, for the three novae respectively. The spectra of Nova M31-2006#9 and Nova M33-2006#1 revealed prominent Balmer (FWHM 1600 km/s) and Fe II emission lines typical of the "Fe II" class in the classification system of Williams (1992 AJ, 104, 725). The spectrum of Nova M32-2006#1, which was obtained much longer after eruption, showed strong H-alpha (FWHM 1300 km/s), along with weaker H-beta, Fe II, and [N II] 5755, indicating that this nova is also a member of the Fe II class, and that it had entered the nebular phase at the time of our observations. In addition to these three novae, we also attempted to obtain a spectrum of Nova M31-2006#7 (CBET 615) on 23-Sep-2006 UT, approximately three weeks after discovery. However, by the time of our observations, the nova had faded to invisibility. An 1800s integration at the reported position reveled no trace of the nova. It is likely that this optical transient was an unusually fast nova, possibly of the "He/N" class. This work is being supported in part by NSF grant AST-0607682.

  17. Progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Raskin, Cody

    Type Ia supernovae are important, but mysterious cosmological tools. Their standard brightnesses have enabled cosmologists to measure extreme distances and to discover dark energy. However, the nature of their progenitor mechanisms remains elusive, with many competing models offering only partial clues to their origins. Here, type Ia supernova delay times are explored using analytical models. Combined with a new observation technique, this model places new constraints on the characteristic time delay between the formation of stars and the first type Ia supernovae. This derived delay time (500 million years) implies low-mass companions for single degenerate progenitor scenarios. In the latter portions of this dissertation, two progenitor mechanisms are simulated in detail; white dwarf collisions and mergers. From the first of these simulations, it is evident that white dwarf collisions offer a viable and unique pathway to producing type Ia supernovae. Many of the combinations of masses simulated produce sufficient quantities of 56 Ni (up to 0.51 solar masses) to masquerade as normal type Ia supernovae. Other combinations of masses produce 56 Ni yields that span the entire range of supernova brightnesses, from the very dim and underluminous, with 0.14 solar masses, to the over-bright and superluminous, with up to 1.71 solar masses. The 56 Ni yield in the collision simulations depends non-linearly on total system mass, mass ratio, and impact parameter. Using the same numerical tools as in the collisions examination, white dwarf mergers are studied in detail. Nearly all of the simulations produce merger remnants consisting of a cold, degenerate core surrounded by a hot accretion disk. The properties of these disks have strong implications for various viscosity treatments that have attempted to pin down the accretion times. Some mass combinations produce super-Chandrasekhar cores on shorter time scales than viscosity driven accretion. A handful of simulations also

  18. NOVA Fall 2002 Teacher's Guide.

    ERIC Educational Resources Information Center

    Ransick, Kristina; Rosene, Dale; Sammons, James; Turck, Mary

    This NOVA teacher's guide presents activities, information, and teaching ideas from the Public Broadcasting System's (PBS) NOVA television program series. Episodes include: (1) "Mysterious Life of Caves" which investigates the role microbes play in the creation of some limestone caves; (2) "Lost Roman Treasure" which follows archaeologists working…

  19. Classifications of Venusian Novae (astra)

    NASA Astrophysics Data System (ADS)

    Aittola, M.; Raitala, J.

    There is rather large population of structures, which are characterized by prominent radial features on Venusian surface. This special group of volcano-tectonic structures with a stellate fracture pattern radiating around a central summit or fracture is called "nova" or "astrum/astra" (e.g. Schubert et al., 1991; Head et al., 1992). We studied the distribution and the characteristics of 74 novae to declare if there is suitable ways to categorize them and to find out how this categorizing could explain the differences in nova characteristics. The nova locations establish that these structures are not distributed sporadically, but display both latitudinal and longitudinal concentrations. Furthermore, it is evident that the geological environments represent the major differences between individual novae with majority of them being in connection to some larger volcano-tectonic unit, in general. The differences in geological surroundings can be used as the base to characterize novae by dividing them to different categories: a) novae locate either within or close to a rather large deformation zone, b) novae locate on plains, c) novae locate close to tessera terrain and d) novae situate within volcanic areas either close to volcanoes or within the area with a high density of coronae. The analysis of this characterization establishes that the geological environments are the main cause for divergent nova characteristics, i.e. differences in morphology, volcanism and topography that on the other hand are possible ways to classify novae. Especially morphological classification (Type I - novae with features radiating from the same point, Type II - radial structures radiating from a fissure or other linear structure, Type III - lava flows or fields covering radiant point area, Type IV - semi-radial structures which do not radiate from a well-defined radiant point, fissure or area) shows correlations between geological environments and the type of the nova. References: Schubert

  20. Nova Delphini 2013: Backyard Analysis of a Classical Nova

    NASA Astrophysics Data System (ADS)

    Reid, Piper

    2014-01-01

    On August 14, 2013, Nova Delphini was discovered by Koichi Itagaki. This nova erupted to a maximum brightness of magnitude 4.4 by August 16, 2013. The extraordinary brightness of this event has allowed many amateur astronomers to have the chance to study it. More than 750 amateur astronomers have contributed to the AAVSO photometry database of Nova Delphini.1 The amount and quality of spectroscopic data gathered is unprecedented as well, as over 700 individual spectra have been collected so far in the ARAS database.2 A nova is a class of variable star that undergoes a cataclysmic eruption, which can be observed through a sudden increase in brightness that declines over a series of months or years. At the center of a nova is an accreting white dwarf star which is collecting hydrogen from its surroundings. The accreting mass causes a nuclear reaction on the surface of the white dwarf and as the pressure increases the reaction becomes super-critical and a thermonuclear runaway is ignited causing the brightness increase as well as triggering the ejection of a shell of material form the star. The stages of a classical nova outburst are outlined along with techniques available to amateur astronomers for study of these phenomena. The author’s equipment and software setup are detailed. Results obtained using a low resolution grating, Schmidt-cassegrain telescope and CCD camera that were acquired while Nova Delphini was in the “fireball stage” 3 and subsequent “iron curtain phase”3 are compared and discussed. Results obtained using a high resolution spectroscope, Schmidt-cassegrain telescope and CCD camera that were acquired during the “lifting of the iron curtain phase”3 are also presented. References 1. Turner, Rebecca. “AAVSO - Nova Del 2013” 20 Aug 2013 Web. 8 Sep 2013 nova-del-2013> 2. Tessier, Francois. “ARAS Spectral Database - Nova-Del-2013” 22 Sep 2013 Web. 22 Sep 2013 Novae/Nova

  1. Olivier Chesneau's Work on Novae

    NASA Astrophysics Data System (ADS)

    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.

  2. HET Spectra of Three Recent Extragalactic Novae

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.; Coelho, E. A.; Misselt, K. A.; Bode, M. F.; Darnley, M. J.; Quimby, R.

    2006-10-01

    We report optical spectroscopic observations (4280Å - 7280Å) obtained with the HET of three extragalactic novae: Nova M31 2006 No. 9 (ATEL #887), Nova M32 2006 No. 1 (CBET #591), and Nova M33 2006 No. 1 (CBET #655). The spectra were obtained on 24 Sep 2006 UT, 30 Sep 2006 UT, and 02 Oct 2006 UT, corresponding to approximately 6, 65, and 4 days post discovery, for the three novae respectively.

  3. Argonne's Vilas Pol on NOVA!

    SciTech Connect

    2011-01-01

    Can innovations in materials science help clean up our world? Argonne's material scientist Vilas Pol guest starred on NOVA's "Making Stuff: Cleaner," where David Pogue explored the rapidly-developing science and business of clean energy.

  4. Nova reaction rates and experiments

    NASA Astrophysics Data System (ADS)

    Bishop, S.; Herlitzius, C.; Fiehl, J.

    2011-04-01

    Oxygen-neon novae form a subset of classical novae events known to freshly synthesize nuclei up to mass number A≲40. Because several gamma-ray emitters lie in this mass range, these novae are also interesting candidates for gamma-ray astronomy. The properties of excited states within those nuclei in this mass region play a critical role in determining the resonant (p,γ) reaction rates, themselves, largely unknown for the unstable nuclei. We describe herein a new Doppler shift lifetime facility at the Maier-Leibnitz tandem laboratory, Technische Universität München, with which we will map out important resonant (p,γ) nova reaction rates.

  5. Argonne's Vilas Pol on NOVA!

    ScienceCinema

    None

    2016-07-12

    Can innovations in materials science help clean up our world? Argonne's material scientist Vilas Pol guest starred on NOVA's "Making Stuff: Cleaner," where David Pogue explored the rapidly-developing science and business of clean energy.

  6. The photometric period of the recurrent Nova T Pyxidis

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Landolt, Arlo U.; Vogt, Nikolaus; Buckley, David; Warner, Brian; Walker, Alistair R.; Bond, Howard E.

    1992-01-01

    The paper presents 1713 photometric measurements of T Pyx from 1966 to 1990. The light curve of T Pyx shows roughly sinusoidal variations with a typical amplitude of 0.09 mag and a time scale of 2 hr. Discrete Fourier transforms of data from individual nights and runs reveal a highly significant periodic modulation. This modulation is proven to be coherent only on time scales shorter than from 6 d to under 1 d. The present period for the modulation is 0.07616 +/- 0.00017 d. Since other stars have variable photometric periods (possibly related to the superhump phenomenon) which are slightly different from the orbital period, an orbital period of about 0.073 d for T Pyx is suggested.

  7. Swift UVOT observations of the SMC nova MASTER OT J010603.18-744715.8

    NASA Astrophysics Data System (ADS)

    Kuin, N. P. M.; Page, K. L.; Williams, S. C.; Darnley, M. J.; Shore, S. N.; Walter, F. M.

    2016-10-01

    Since its discovery at magnitude 10.9 on 2016-10-14.19341 UT (Shumkov et al, ATEL #9621) and spectroscopic confirmation (Williams and Darnley, ATEL #9628) pre-discovery data from the OGLE team (Mroz and Udalski, ATEL #9622, and MASTER (Lipunov et al., ATEL #9631) revealed the progenitor magnitude and pushed back the appearance of the nova to magnitude 8.5 on 2016, Oct 9.808.

  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

    NASA Technical Reports Server (NTRS)

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

    NASA Astrophysics Data System (ADS)

    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.

  10. The Crab Nebula's progenitor

    NASA Technical Reports Server (NTRS)

    Nomoto, K.; Sugimoto, D.; Sparks, W. M.; Fesen, R. A.; Gull, T. R.; Miyaji, S.

    1982-01-01

    The initial mass of the Crab Nebula's progenitor star is estimated by comparing the observed nebular chemical abundances with detailed evolutionary calculations for 2.4- and 2.6-solar-mass helium cores of stars with masses of 8 to 10 solar masses. The results indicate that the mass of the Crab's progenitor was between the upper limit of about 8 solar masses for carbon deflagration and the lower limit of about 9.5 solar masses set by the dredge-up of the helium layer before the development of the helium-burning convective region. A scenario is outlined for the evolution of the progenitor star. It is suggested that the Crab Nebula was probably the product of an electron-capture supernova.

  11. Spitzer observations of adolescent novae

    NASA Astrophysics Data System (ADS)

    Evans, Aneurin; Gehrz, Robert; Helton, Andrew; Krautter, Joachim; Lyke, James; Polomsky, Elisha; Rushton, Mark; Salama, Alberto; Shore, Steven; Starrfield, Sumner; Truran, James; Wagner, R. Mark; Woodward, Charles

    2006-05-01

    Classical novae (CNe) offer the best opportunity to observe many astrophysical processes (such as dust formation and processing, shaping of nebulae, gas cooling by IR fine structure lines) in `fast forward'. The CN eruption arises following a thermonuclear runaway on the surface of a white dwarf in a semi-detached binary system, following which some 10^-4 Msun of material, enriched in metals, is explosively ejected at ~1000km/s. Following the eruption, CNe vary rapidly, on a timescale ~months, and this necessitates continuous monitoring. Several novae were observed in GO1 as targets-of-opportunity (ToO). We propose to use the Spitzer IRS to observe a sample of novae, including GO1 ToO and several recent (<20years) CNe, to provide us with a well-populated CN parameter space. We aim to determine (i) the ejecta masses, (ii) abundances in the ejected material, (iii) evolution and processing of the CN dust.

  12. Transient classification and novae ejecta

    NASA Astrophysics Data System (ADS)

    Williams, Robert

    2016-07-01

    A third parameter, in addition to luminosity and rate of brightness decline, 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.

  13. Nova LMC 1990 no. 1: The first extragalactic neon nova

    NASA Technical Reports Server (NTRS)

    Sonneborn, George; Shore, Steven N.; Starrfield, Sumner G.

    1990-01-01

    International Ultraviolet Explorer (IUE) observations of nova LMC (Large Magellanic Cloud) 1990 No. 1, the first neon (or ONeMg) nova observed outside the Galaxy are presented. The observations were obtained from 17 Jan. to Mar. 1990, with especially dense coverage during the first 25 days of the outburst. (The neon nova categorization is based on the detection of forbidden Ne 3-4 lines in optical spectra; the ultraviolet neon lines were not detected.) During the first 30 days of the outburst, the radiative losses were dominated by the N 5 delta 1240 and C 4 delta 1550 lines. The maximum ejection velocity was approximately 8000 km/s, based on the blue absorption edge of the C 4 P-Cygni profile. Early in the outburst of Nova LMC 1990 No. 1 the UV luminosity alone was approximately 3 times 10 to the 38th power erg/sec, implying that the bolometric luminosity was well in excess of the Eddington luminosity for a one solar mass object.

  14. NOVAE WITH LONG-LASTING SUPERSOFT EMISSION THAT DRIVE A HIGH ACCRETION RATE

    SciTech Connect

    Schaefer, Bradley E.; Collazzi, Andrew C.

    2010-05-15

    We identify a new class of novae characterized by the post-eruption quiescent light curve being more than roughly a factor of 10 brighter than the pre-eruption light curve. Eight novae (V723 Cas, V1500 Cyg, V1974 Cyg, GQ Mus, CP Pup, T Pyx, V4633 Sgr, and RW UMi) are separated out as being significantly distinct from other novae. This group shares a suite of uncommon properties, characterized by the post-eruption magnitude being much brighter than before eruption, short orbital periods, long-lasting supersoft emission following the eruption, a highly magnetized white dwarf (WD), and secular declines during the post-eruption quiescence. We present a basic physical picture which shows why all five uncommon properties are causally connected. In general, novae show supersoft emission due to hydrogen burning on the WD in the final portion of the eruption, and this hydrogen burning will be long-lasting if new hydrogen is poured onto the surface at a sufficient rate. Most novae do not have adequate accretion for continuous hydrogen burning, but some can achieve this if the companion star is nearby (with short orbital period) and a magnetic field channels the matter onto a small area on the WD so as to produce a locally high accretion rate. The resultant supersoft flux irradiates the companion star and drives a higher accretion rate (with a brighter post-eruption phase), which serves to keep the hydrogen burning and the supersoft flux going. The feedback loop cannot be perfectly self-sustaining, so the supersoft flux will decline over time, forcing a decline in the accretion rate and the system brightness. We name this new group after the prototype, V1500 Cyg. V1500 Cyg stars are definitely not progenitors of Type Ia supernovae. The V1500 Cyg stars have similar physical mechanisms and appearances as predicted for nova by the hibernation model, but with this group accounting for only 14% of novae.

  15. The Video Nova Authoring System.

    ERIC Educational Resources Information Center

    Edwards, Sheila

    1986-01-01

    The Video Nova Authoring System (VNAS) was developed by computer programmers and instructional designers to provide noncomputer programmers with a tool to design interactive videodisc programs. VNAS allows the instructor complete design freedom, and although menu-driven, doesn't rely on preset lesson plans. Illustrations and sources for evaluation…

  16. Nova Eri 2009 (prediscovery images)

    NASA Astrophysics Data System (ADS)

    Allen, Bill; Postigo, A. De Ugarte; Castro-Tirado, A. J.; Gorosabel, J.; Jelinek, M.; Cunniffe, R.; Guziy, S.; Kubanek, P.; Yock, P.; Bond, I.; Christie, G.

    2010-01-01

    Using the CASANDRA-3 all-sky camera (Castro-Tirado et al. 2008, Proceedings of the SPIE, Volume 7019, pp. 70191V-70191V-9) at the BOOTES-3 robotic observatory located in Blenheim, New Zealand we have observed the pre-discovery images of Nova Eri 2009 determining the following magnitudes. The reference star used was HD 30076, m = 5.87.

  17. NOVA Fall 1998 Teacher's Guide.

    ERIC Educational Resources Information Center

    Colombo, Luann

    This teacher's guide is designed to accompany the PBS television program "NOVA." Six science activities correspond to: (1) "Lost at Sea: The Search for Longitude,, which researches and charts the shortest course to circumnavigate the globe; (2) "Chasing El Nino," which formulates a question and designs an experiment to evaluate the accuracy of…

  18. Multidimensional Modeling of Nova Outbursts

    NASA Astrophysics Data System (ADS)

    José, J.

    2014-12-01

    Classical novae repeatedly eject ˜10-4-10-5 M⊙ enriched in nuclear-processed material relative to solar abundances, recurring on intervals of decades to tens of millennia. They are probably the main sources of Galactic 15N, 17O and 13C. The origin of the large enhancements and inhomogeneous distribution of these species observed in high-resolution spectra of ejected nova shells has, however, remained unexplained for almost 50 years. Several mechanisms, including mixing by diffusion, shear or resonant gravity waves, have been proposed in the framework of one-dimensional or two-dimensional simulations, but none has proven successful because convective mixing can only be modeled accurately in three-dimensions. This review focuses on multidimensional modeling of nova explosions, with emphasis on mixing at the core-envelope interface. Examples of buoyant fingering driving vortices from the Kelvin-Helmholtz instability, leading to enrichment of the accreted envelope with material from the outer white dwarf core, will be described. This mixing mechanism naturally accounts for large-scale chemical inhomogeneities. Preliminary simulations of the interaction between the nova ejecta and the secondary star will also be outlined.

  19. An observational case against nova hibernation

    NASA Technical Reports Server (NTRS)

    Naylor, T.; Charles, P. A.; Mukai, K.; Evans, A.

    1992-01-01

    We use WHT spectroscopy and imaging to show that nova Vul 1670 (= CK Vul) has been incorrectly identified, and thus its luminosity cannot be used as evidence that novae fade into a 'hibernation' phase within 300 yr of their outbursts. INT spectroscopy is used to correct the magnitude of nova Sge 1783 (= WY Sge) for inclination, this result also implying that novae do not fade significantly. We therefore suggest that, while novae decline in the first 60 yr after outburst, thereafter their luminosity remains constant, and they never undergo a 'hibernation' phase. We show that this idea is consistent with the space density of novae and novalike variables, the outburst interval of SS Cyg and the current luminosities of old novae.

  20. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL

    SciTech Connect

    Shara, Michael M.; Mizusawa, Trisha; Zurek, David; Wehinger, Peter; Martin, Christopher D.; Neill, James D.; Forster, Karl; Seibert, Mark

    2012-10-20

    We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam 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, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of {approx}5 Multiplication-Sign 10{sup -5} M {sub Sun }, typical of classical novae.

  1. Possible Nova in M31

    NASA Astrophysics Data System (ADS)

    Pietsch, W.; Burwitz, V.; Rodriguez, J.; Garcia, A.

    2006-05-01

    We report the discovery of a possible nova in M31 on an rgb and an unfiltered CCD image (2006, April 26.273, 15.9 mag; 28.263, 16.1 mag) obtained with the Bradford Robotic Telescope Galaxy at the Tenerife Observatory (365mm, f/11 Schmidt-Cassegrain telescope with a 0.67 focal reducer with a FLI MaxCam ME2 1k x 1k CCD camera with 13Mu sq. pixels). The position obtained for the nova candidate is RA = 00h 43m 13.38s, Dec = +41° 16' 58.9" with an accuracy of 0.3".

  2. The NOvA experiment

    SciTech Connect

    Ray, Ronald E.

    2008-01-01

    The NOvA Project will construct a 15 kt Far Detector 835 km from Fermilab at Ash River Minnesota, a 220 ton Near Detector on the Fermilab site and upgrade the existing NuMI beamline from 400 kW to 700 kW. The detector technology is liquid scintillator captured in reflective rigid PVC cells. The light is captured using WLS fibre and routed to avalanche photo diodes. NO?A is designed to observe the appearance of electron neutrinos, determine the value of sin{sup 2}(2{theta}{sub 13}) and begin the study of CP violation in the neutrino sector. NO?A is the only currently approved experiment with the ability to determine the neutrino mass ordering. The NOvA physics program and projected sensitivities are described in this report.

  3. Nucleosynthesis and the nova outburst

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10(sup 8)K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into (beta)(sup +)-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M(sub (circle dot)), 1.25M(sub (circle dot)), and 1.35M(sub (circle dot)) white dwarfs. Our results show that novae can produce (sup 22)Na, (sup 26)Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

  4. Nucleosynthesis and the nova outburst

    SciTech Connect

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

    1995-12-31

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10{sup 8}K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into {beta}{sup +}-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M{sub {circle_dot}}, 1.25M{sub {circle_dot}}, and 1.35M{sub {circle_dot}} white dwarfs. Our results show that novae can produce {sup 22}Na, {sup 26}Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. NUCLEAR THERMOMETERS FOR CLASSICAL NOVAE

    SciTech Connect

    Downen, Lori N.; Iliadis, Christian; Jose, Jordi; Starrfield, Sumner

    2013-01-10

    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 {sup 30}P(p, {gamma}){sup 31}S 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 {sub Sun} (V838 Her), 1.18-1.21 M {sub Sun} (V382 Vel), {<=}1.3 M {sub Sun} (V693 CrA), {<=}1.2 M {sub Sun} (LMC 1990 no. 1), and {<=}1.2 M {sub Sun} (QU Vul).

  7. Cecilia Payne-Gaposchkin, Henry Norris Russell Lecture: Fifty Years of Novae

    NASA Astrophysics Data System (ADS)

    Burbidge, E. M.

    1999-05-01

    It is easy to pick out my most memorable meeting of the AAS: the 149th meeting held in January, 1977, and hosted by the University of Hawaii, in Honolulu, HI. It was the meeting at which two traditions of the Society were broken, and we moved into the era of equal opportunity for women astronomers. Cecilia Payne-Gaposchkin received the highest award of the AAS: the Henry Norris Russell Lectureship. This award had never before been available to women, otherwise Cecilia would, years earlier, have been honored for the many achievements in her lifetime of renowned astronomical research. And I, the first woman to be elected President of the AAS, had the honor of presenting the illuminated scroll to Cecilia, and of introducing her on the platform where she delivered the Henry Norris Russell Prize Lecture, entitled ``Fifty Years of Novae"(1) . Cecilia opened by comparing the experience of young and old scientists in achieving exciting results from their research, and then led us through the history of the discoveries of and about some famous novae. She described the physical picture that emerged from studies of their light curves, their spectra, and the discovery of their binary nature. Three important tables were included, listing data on cataclysmic binaries (dwarf novae) and their link to the nova phenomenon in general. She recalled that she and Sergei Gaposchkin had hesitated between the names catastrophic and cataclysmic for the dwarf novae, and decided on the latter, from the dictionary definitions of those two terms: ``a cataclysm is a great and general flood" while a catastrophe ``is a final event". The nova phenomenon is recurrent, as are the dwarf novae, and both involve an outpouring of a flood of energy. She concluded by describing her 50 years' experience with novae as presenting ``the contemporary portrait of a nova", rather than a final picture, and by forecasting that the next 50 years of discovering and studying novae will be as full of surprises as the

  8. Spitzer Space Telescope observations of the slow classical nova V1186 Sco

    NASA Astrophysics Data System (ADS)

    Schwarz, G. J.; Woodward, C. E.; Lynch, D. K.; Rudy, R.; Ruch, G.; Helton, A.; Venturini, C. C.; Lyke, J. E.; Bode, M. F.; Spitzer CY1 GO ToO Nova Team

    2005-12-01

    The first classical nova observed in our Spitzer Cycle 1 ToO program (PID 2333) was V1186 Sco. This slow nova exhibited a light curve with multiple secondary peaks similar to PW Vul. Visual maximum occurred on 9 July 2004 while the time to decline 2 magnitudes, t2, was 25 days. However, the erratic nature of the light curve makes any determination of intrinsic properties based on the decline times (e.g. luminosity) problematic. Spitzer 5-37 micron spectra were obtained of V1186 Sco and V1187 Sco in late September 2004 and March 2005. V1187 Sco was a very fast nova that was discovered only a few days after V1186 Sco. The first spectra of V1187 Sco showed strong forbidden lines, primarily of neon and magnesium, superimposed on a weak hydrogen recombination spectrum (Lynch et al. 2005, ApJ in press). Both the early and late evolutionary epoch spectra of V1186 Sco were dominated by hydrogen lines. Not unexpected due to its extreme decline time and likely ONeMg white dwarf progenitor, V1187 Sco was dominated by very high ionization "coronal" lines of [Mg V], [Mg VII], [Ar V], [Ne V], and [Ne VI] when Spitzer observations resumed in March 2005. Due to its much slower evolution, the Spitzer data of V1186 Sco obtained the same month showed a greatly weakened hydrogen recombination spectrum with a surprising emergence of the [Ne II] (12.8 micron) as the strongest line. It is not clear if the V1186 Sco outburst occurred on a an ONeMg white dwarf as our complementary ground based optical and near-IR spectroscopy obtained during this later epoch show none of the typical characteristics of an ONeMg nova. However, given the rather slow development of this object it might be too early to make any determination of the white dwarf progenitor.

  9. Non-LTE luminosity and abundance diagnostics of classical novae in x-rays

    NASA Astrophysics Data System (ADS)

    Nemeth, Peter

    2010-06-01

    Classical novae have fundamental importance in astronomy as they are relevant to both an understanding of individual stellar evolution and to taking proper distance measurements on galactic and cosmological scales. Also, novae are significant sources of interstellar material, especially carbon, nitrogen, oxygen and aluminum. 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 the brightest, type Ia supernovae. Just 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 of novae. It was necessary to incorporate atomic data for the highest ionization stages for elements ranging from hydrogen to iron for both programs Atomic data on energy levels, bound-free, bound-bound transitions and natural broadening were taken from NIST and TOPbase. Extensive tests revealed the importance of line opacities on atmospheric parameters and on the final spectra. A correlation can be defined between effective temperature and surface gravity. The spectral appearance is not very sensitive to the joint changes of both. Due to this effect both parameters might be over-estimated with static models. These tests also showed that N VI and N VII lines are good indicators of effective temperature. Model fitting of V4743 Sgr and V2491 Cyg confirmed the anticipated impact of modeling geometry and stellar wind. Both novae are close to or over the Eddington limit. Ionization balance and line profiles also indicate

  10. Nova pulse power design and operational experience

    NASA Astrophysics Data System (ADS)

    Whitham, K.; Larson, D.; Merritt, B.; Christie, D.

    1987-01-01

    Nova is a 100 TW Nd++ solid state laser designed for experiments with laser fusion at Lawrence Livermore National Laboratory (LLNL). The pulsed power for Nova includes a 58 MJ capacitor bank driving 5336 flashlamps with millisecond pulses and subnanosecond high voltages for electro optics. This paper summarizes the pulsed power designs and the operational experience to date.

  11. Nova shell observation of V2275 Cyg

    NASA Astrophysics Data System (ADS)

    Esenoglu, Hasan H.; Balman, Solen; Saygac, A. Talat

    2016-07-01

    We present a recent search for nova shell of V2275 Cyg after its eruption of 9 years, using narrow bands of H-alpha, OIII and H-alpha-continuum images taken with RTT150 telescope at TUG. They were taken in November 2nd, 2010 with exposures of 600sec. There is uncertain in the literature whether the nova shell is visible in H-alpha. In this work the nova disappears on frame of OIII (wavelengt of 500.7nm with band width of 5nm) when it is faint apparent on the frames of both H-alpha and H-alpha continuum. We will calculate a new angular diameter of the nova shell by using the nebular expantion method if the data allow to measure seeing values of the nova and neighbor stars.

  12. BVRJK observations of Northern Hemisphere old novae

    NASA Technical Reports Server (NTRS)

    Szkody, Paula

    1994-01-01

    BVR photometry has been accomplished for 65 objects in the Duerbeck atlas along with J photometry of 52 and K of 30 objects. The (B - V), (V - R), and (V - J) colors are compiled with those available in the literature to assess the color change of novae as a function of time since outburst. Using available reddening values results in a list of 42 (B - V), 28 (V - R), and 38 (V - J) dereddened colors for novae that are from 1 to 319 years past outburst. The results indicate all the colors cluster about zero, with no obvious transition to red values as would be expected for novae undergoing a hibernation scenario. This indicates the accretion disk is sustained for at least 200 years after outburst. It is also apparent that red novae with giant secondaries and/or unusual properties readily stand out from the normal novae in color.

  13. Nova-driven winds in globular clusters

    NASA Technical Reports Server (NTRS)

    Scott, E. H.; Durisen, R. H.

    1978-01-01

    Recent sensitive searches for H-alpha emission from ionized intracluster gas in globular clusters have set upper limits that conflict with theoretical predictions. It is suggested 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 to globular cluster X-ray sources is also considered.

  14. Terra Nova Bay Polynya, Antarctica

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In Terra Nova Bay, off the Scott Coast of Victoria Land, Antarctica, a large pocket of open water persists throughout most of the Southern Hemisphere winter, even while most of the rest of the Antarctic coastline is firmly embraced by the frozen Southern Ocean. This pocket of open water--a polynya--results from exceptionally strong winds that blow downslope from the Trans-Antarctic Mountains. These fierce katabatic winds drive the sea ice eastward. Since the dominant ice drift pattern in the area is northward, the Drygalski Ice Tongue prevents the bay from being re-populated with sea ice. This image of the Terra Nova Bay polynya was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on October 16, 2007. Sea ice sits over the Ross Sea like a cracked and crumbling windshield. Blue-tinged glaciers flow down from the Trans-Antarctic Mountains. Although glaciers can appear blue because of melt water, they can also get that tint when the wind scours and polishes the ice surface. Given the strength of the katabatic winds along this part of the Antarctic coast, it is likely that the blue color of these glaciers is a result of their having been swept clean of snow. The large image has a spatial resolution (level of detail) of 250 meters per pixel.

  15. BLOBS IN SPACE: THE LEGACY OF A NOVA

    NASA Technical Reports Server (NTRS)

    2002-01-01

    TThe prolific number of eruptions by the recurrent nova T Pyxidis has attracted the attention of many telescopes. The image on the left, taken by a ground-based telescope, shows shells of gas around the star that were blown off during several eruptions. Closer inspection by the Hubble Space Telescope (right-hand image), however, reveals that the shells are not smooth at all. In fact, this high-resolution image shows that the shells are actually more than 2,000 gaseous blobs packed into an area that is 1 light-year across. Resembling shrapnel from a shotgun blast, the blobs may have been produced by the nova explosion, the subsequent expansion of gaseous debris, or collisions between fast-moving and slow- moving gas from several eruptions. False color has been applied to this image to enhance details in the blobs. The ground-based image was taken Jan. 19, 1995 by the European Southern Observatory's New Technology Telescope in La Silla, Chile. The Hubble telescope picture is a compilation of data taken on Feb. 26, 1994, and June 16, Oct. 7, and Nov. 10, 1995, by the Wide Field and Planetary Camera 2. T Pyxidis is 6,000 light-years away in the dim southern constellation Pyxis, the Mariner's Compass. Credits: Mike Shara, Bob Williams, and David Zurek (Space Telescope Science Institute); Roberto Gilmozzi (European Southern Observatory); Dina Prialnik (Tel Aviv University); and NASA.

  16. Newly Determined Explosion Center of Tycho's Supernova and the Implications for Proposed Ex-companion Stars of the Progenitor

    NASA Astrophysics Data System (ADS)

    Xue, Zhichao; Schaefer, Bradley E.

    2015-08-01

    “Star G,” near the center of the supernova remnant of Tycho’s SN 1572, has been claimed to be the ex-companion star of the exploding white dwarf, thus pointing to the progenitor being like a recurrent nova. This claim has been controversial, but there have been no confident proofs or disproofs. Previously, no one has seriously addressed the question as to the exact explosion site in 1572. We now provide accurate measures of the supernova position by two radically different methods. Our first method is to use the 42 measured angular distances between the supernova in 1572 and bright nearby stars, with individual measures being as good as 84 arcsec, and all resulting in a position with a 1σ error radius of 39 arcsec (including systematic uncertainties). Our second method is to use a detailed and state-of-the-art one-dimensional expansion model for 19 positions around the edge of the remnant, where the swept-up material has measured densities, and we determine the center of expansion with a chi-square fit to the 19 measured radii and velocities. This method has a 1σ error radius of 7.5 arcsec. Both measures are substantially offset from the geometric center, and both agree closely, proving that neither has any significant systematic errors. Our final combined position for the site of the 1572 explosion is J2000 α = 0h25m15.ˢ36, δ =64^\\circ 8\\prime 40\\buildrel{\\prime\\prime}\\over{.} 2, with a 7.3 arcsec 1σ uncertainty. Star G is rejected at the 8.2σ confidence level. Our new position lies mostly outside the region previously searched for ex-companion stars.

  17. Automated Searches for Extragalactic Novae

    NASA Astrophysics Data System (ADS)

    Darnley, M. J.

    2005-06-01

    Classical novae (CNe) are interacting binary systems in which the white dwarf undergoes unpredictable explosive outbursts. The energy of a nova outburst is only surpassed by that of gamma-ray bursts, supernovae and a small number of luminous blue variables. However, the outbursts of CNe are far more common than any of these other stars. Due to their brightness and occurrence in both Population I and Population II systems, novae are potentially important as extragalactic distance indicators and tools in the exploration of binary star evolution in galaxies. The POINT-AGAPE survey is an optical search for gravitational micro-lensing events towards the Andromeda galaxy (M31). As well as micro-lensing, the survey is sensitive to many different classes of variable stars and transients, including CNe. In this work we describe the automated detection and selection pipeline used to identify M31 CNe and we present the resulting catalogue of 20 strong CN candidates observed over three seasons. The CNe we discover are observed both in the M31 bulge region as well as over a wide area of the M31 disc. Nine of the CNe are caught during the final rise phase (which is often missed in Galactic novae) and all are well sampled in at least two colours. The excellent light-curve coverage has allowed us to detect and classify CNe over a wide range of speed classes, from very fast to very slow. Among the light curves is, for example, a moderately fast CN exhibiting entry into a deep transition minimum, followed by its final decline. We have also observed in detail a very slow CN which faded by only 0.01 mag day^{-1} over a 150 day period. The CN catalogue constitutes a uniquely well-sampled and objectively-selected data set with which to study the statistical properties of CNe in M31. As a by-product, we have detected other interesting variable objects, including one of the longest period and most luminous Mira variables. An analysis of the MMRD relationship in M31 was performed using the

  18. Progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Maeda, Keiichi; Terada, Yukikatsu

    2016-07-01

    Natures of progenitors of type Ia Supernovae (SNe Ia) have not yet been clarified. There has been long and intensive discussion on whether the so-called single degenerate (SD) scenario or the double degenerate (DD) scenario, or anything else, could explain a major population of SNe Ia, but the conclusion has not yet been reached. With rapidly increasing observational data and new theoretical ideas, the field of studying the SN Ia progenitors has been quickly developing, and various new insights have been obtained in recent years. This paper aims at providing a summary of the current situation regarding the SN Ia progenitors, both in theory and observations. It seems difficult to explain the emerging diversity seen in observations of SNe Ia by a single population, and we emphasize that it is important to clarify links between different progenitor scenarios and different sub-classes of SNe Ia.

  19. The NOvA Technical Design Report

    SciTech Connect

    Ayres, D.S.; Drake, G.R.; Goodman, M.C.; Grudzinski, J.J.; Guarino, V.J.; Talaga, R.L.; Zhao, A.; 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

  20. New Insights into the Evolution of Galactic Classical Novae

    NASA Astrophysics Data System (ADS)

    Helton, L. Andrew

    2010-05-01

    Classical novae (CNe) are violent thermonuclear explosions arising on the surface of white dwarfs in binary systems and are contributors to the chemical evolution of the interstellar medium through the production and ejection of copious amounts of metal-rich material. Observations and modeling of CNe eruptions illuminate numerous fundamental processes of astrophysical interest, including non-equilibrium thermonuclear runaway, radiative processes in dynamic nebular environments, binary star interaction, as well as dust condensation and grain growth. Here I summarize key findings of over 30 Galactic CNe obtained as part of a 5 year, panchromatic optical/infrared observing campaign using Spitzer, Gemini, and other ground based optical facilities. In particular, synoptic observations of V1065 Cen, V574 Pup, V2467 Cyg, and V458 Vul, which exhibit spectra rich in metals (e.g O, Ne, Mg, S, Ar, Ca, and Fe) produced during the thermonuclear runaway and through dredge up from the surface layers of the underlying WD, yield new estimates of WD progenitor masses and composition, ejecta masses, and absolute abundances. Dusty novae such as V1065 Cen, V2362 Cyg, and V2361 Cyg, produce a variety of grain types as revealed by emission features characteristic of silicates, hydrogenated amorphous carbon dust, and PAH-like molecules, often in the same system. Our data set is exceptional in that observations of many targets commence immediately after eruption and follow the development for hundreds of days post-outburst providing unique insight into the evolution of conditions within the ejecta including the complete cycle of growth, processing, and dissipation of dust grains. Support for this dissertation research was provided in part by the National Science Foundation and various JPL/Caltech contracts to the University of Minnesota.

  1. Nova laser alignment control system

    SciTech Connect

    Van Arsdall, P.J.; Holloway, F.W.; McGuigan, D.L.; Shelton, R.T.

    1984-03-29

    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.

  2. Circumstellar Dust in Symbiotic Novae

    NASA Astrophysics Data System (ADS)

    Jurkic, T.; Kotnik-Karuza, D.

    2015-12-01

    We present a model of inner dust regions around the cool Mira component of the two symbiotic novae, RR Tel and HM Sge, based on the near-IR photometry, ISO spectra and mid-IR interferometry. The dust properties were determined using the DUSTY code. A compact circumstellar silicate dust shell with inner dust shell temperatures between 900 K and 1300 K and of moderate optical depth can explain all the observations. RR Tel shows the presence of an equatorially enhanced dust density during minimum obscuration. Obscuration events are explained by an increase in optical depth caused by the newly condensed dust. The mass loss rates are significantly higher than in intermediate-period single Miras but in agreement with longer-period O-rich AGB stars.

  3. Multiwavelength Modeling of Nova Atmospheres

    NASA Technical Reports Server (NTRS)

    Hauschildt, P. H.; Starrfield, S.

    1997-01-01

    We have analyzed the early optically thick ultraviolet spectra of Nova OS And 1986 using a grid of spherically symmetric, non-LTE, line-blanketed, expanding model atmospheres and synthetic spectra with the following set of parameters: 5,000 less than or equal to T(sub model) less than or equal to 60,000K, solar abundances, (rho)(alpha) r(sup -3), v(sub max) = 2000 km/s, L = 6 x 10(exp 4) solar luminosity, and a statistical or microturbulent velocity of 50 km/s. We used the synthetic spectra to estimate the model parameters corresponding to the observed IUE spectra. The fits to the observations were then iteratively improved by changing the parameters of the model atmospheres, in particular T(sub model) and the abundances, to arrive at the best fits to the optically thick pseudo-continuum and the features found in the IUE spectra. The IUE spectra show two different optically thick subphases. The earliest spectra, taken a few days after maximum optical light, show a pseudo-continuum created by overlapping absorption lines. The later observations, taken approximately 3 weeks after maximum light, show the simultaneous presence of allowed, semi-forbidden, and forbidden lines in the observed spectra. Analysis of these phases indicate that OS And 86 had solar metallicities except for Mg which showed evidence of being underabundant by as much as a factor of 10. We determine a distance of 5.1 kpc to OS And 86 and derive a peak bolometric luminosity of approximately 5 x 10(exp 4) solar luminosity. The computed nova parameters provide insights into the physics of the early outburst and explain the spectra seen by IUE. Lastly, we find evidence in the later observations for large non-LTE effects of Fe II which, when included, lead to much better agreement with the observations.

  4. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1989-01-01

    The physical processes generating nova eruptions are reviewed, along with the effects on nova eruptions of binary-system parameters such as the chemical composition or mass of the white dwarf and the mass accretion rate. Also considered are the possible metamorphosis from dwarf to classical novae and back again, X-ray and gamma-ray emission from novae, and the characteristics and distributions of novae in globular clusters and extragalactic systems. Limitations of the thermonuclear runaway model are discussed. 159 references.

  5. Nova Sco 2011 No. 2 = PNV J16364440-4132340 = PNV J16364300-4132460

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2011-09-01

    Announcement of discovery of Nova Sco 2011 No. 2 = PNV J16364440-4132340 = PNV J16364300-4132460. Discovered independently by John Seach (Chatsworth Island, NSW, Australia, on 2011 Sep. 06.37 UT at mag=9.8 (DSLR)) and by Yuji Nakamura (Kameyama, Mie, Japan, on 2011 Sep. 06.4313 UT at mag=9.7 C (CCD)). Posted on the IAU Central Bureau for Astronomical Telegrams Transient Object Confirmation Page (TOCP) as PNV J16364440-4132340 (Nakamura) and PNV J16364300-4132460 (Seach); identifications consolidated in VSX under PNV J16364440-4132340. Spectra obtained by A. Arai et al. on 2011 Sep. 7.42 UT suggest a highly reddened Fe II-type classical nova. Spectra by F. Walter and J. Seron obtained Sep. 2011 8.091 UT confirm a young galactic nova; they report spectra are reminiscent of an early recurrent nova. Initially announced in AAVSO Special Notice #251 (Matthew Templeton) and IAU Central Bureau Electronic Telegram 2813 (Daniel W. E. Green, ed.). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  6. Mesenchymal progenitor cells for the osteogenic lineage

    PubMed Central

    Ono, Noriaki; Kronenberg, Henry M.

    2015-01-01

    Mesenchymal progenitors of the osteogenic lineage provide the flexibility for bone to grow, maintain its function and homeostasis. Traditionally, colony-forming-unit fibroblasts (CFU-Fs) have been regarded as surrogates for mesenchymal progenitors; however, this definition cannot address the function of these progenitors in their native setting. Transgenic murine models including lineage-tracing technologies based on the cre-lox system have proven to be useful in delineating mesenchymal progenitors in their native environment. Although heterogeneity of cell populations of interest marked by a promoter-based approach complicates overall interpretation, an emerging complexity of mesenchymal progenitors has been revealed. Current literatures suggest two distinct types of bone progenitor cells; growth-associated mesenchymal progenitors contribute to explosive growth of bone in early life, whereas bone marrow mesenchymal progenitors contribute to the much slower remodeling process and response to injury that occurs mainly in adulthood. More detailed relationships of these progenitors need to be studied through further experimentation. PMID:26526380

  7. Old Novae and the SW Sextantis Phenomenon

    NASA Astrophysics Data System (ADS)

    Schmidtobreick, L.; Tappert, C.

    2014-12-01

    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.

  8. CCD observations of old nova fields

    SciTech Connect

    Downes, R.A.; Szkody, P.; Washington Uni., Seattle )

    1989-06-01

    The discovery of CK Vulpeculae (Nova 1670) has prompted a major review of ideas concerning the long-term development of novae. Unfortunately, there are very few recovered novae old enough to provide confirmation (or rejection) of the new hibernation scenario. CCD images of seven old nova fields, and R band photometry for four fields, have been obtained in an attempt to recover these objects in quiescence. A strong candidate for U Leonis, and a possible counterpart for T Bootis, are found. For three other fields, weak candidates have been found. Finding charts and colors are presented for the seven fields observed. The R light curves of U Leo, indicating an orbital period of 192.5 or 385.0 min, are shown. 14 refs.

  9. CCD observations of old nova fields

    NASA Technical Reports Server (NTRS)

    Downes, Ronald A.; Szkody, Paula

    1989-01-01

    The discovery of CK Vulpeculae (Nova 1670) has prompted a major review of ideas concerning the long-term development of novae. Unfortunately, there are very few recovered novae old enough to provide confirmation (or rejection) of the new 'hibernation' scenario. CCD images of seven old nova fields, and R band photometry for four fields, have been obtained in an attempt to recover these objects in quiescence. A strong candidate for U Leonis, and a possible counterpart for T Bootis, are found. For three other fields, weak candidates have been found. Finding charts and colors are presented for the seven fields observed. The R light curves of U Leo, indicating an orbital period of 192.5 or 385.0 min, are shown.

  10. Pulse shaping on the Nova laser system

    SciTech Connect

    Lawson, J.K.; Speck, D.R.; Bibeau, C.; Weiland, T.L.

    1989-02-06

    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.

  11. CNO nucleosynthesis and the nova outburst

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    Predictions for CNO nucleosynthesis by the classical nova outburst are presented. Properties of the nova phenomenon pertinent to the production of CNO isotopes are discussed, the effect of beta(+) unstable nuclei on outburst evolution is examined, and the need for enhanced CNO nuclei in the envelope is described. Possible mechanisms for producing such enhancement are considered, and recent observations of enhanced CNO nuclei in nova ejecta are reviewed. Results of model evolutionary calculations are outlined which show that a thermonuclear runaway in the hydrogen envelope of a carbon-oxygen white dwarf can reproduce the gross features of the classical nova outburst, that the behavior of the outburst depends at least on the hydrogen-envelope mass and the degree of CNO enhancement, and that all degrees of isotopic enhancement result in an outburst that may be compared with observed events. Two enhancement mechanisms are identified, both of which involve mixing in the envelope.

  12. Copernicus observations of Nova Cygni 1975

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Snow, T. P.; Upson, W. L.; Anderson, R.; Starrfield, S. G.; Gallagher, J. S.; Friedjung, M.; Linsky, J. L.; Henry, R. C.; Moos, H. W.

    1977-01-01

    Near-ultraviolet radiation from Nova Cygni 1975 was detected by the Copernicus satellite on five occasions from 1975 September 1 to 1975 September 9. The nova was not seen in the UV after this date. The principal result was the observation of a broad emission feature from the Mg II doublet at 2800 A. The absence of strong UV radiation at shorter wavelengths suggests that these lines are produced by collisional excitation in the outer layers of an expanding shell with electron temperature of approximately 4000 K. The absence of observed emission lines from highly ionized species indicates that the amount of material with log T between 4.4 and 5.7 is less than 0.001 times that which produces the Mg II emission. The continuum flux in the near-UV decreased as the nova evolved, showing that the total luminosity decreased as the nova faded in the visible.

  13. Rate of nova production in the Galaxy

    SciTech Connect

    Liller, W.; Mayer, B.

    1987-07-01

    The ongoing PROBLICOM program in the Southern Hemisphere now makes it possible to derive a reliable value for the overall production rate of Galactic novae. The results, 73 + or - 24/y, indicates that the Galaxy outproduces M 31 by a factor of two or three. It is estimated that the rate of supernova ejecta is one and a half orders of magnitude greater than that of novae in the Galaxy. 15 references.

  14. Circumstellar dust in symbiotic novae

    NASA Astrophysics Data System (ADS)

    Jurkic, Tomislav; Kotnik-Karuza, Dubravka

    2015-08-01

    Physical properties of the circumstellar dust and associated physical mechanisms play an important role in understanding evolution of symbiotic binaries. We present a model of inner dust regions around the cool Mira component of the two symbiotic novae, RR Tel and HM Sge, based on the long-term near-IR photometry, infrared ISO spectra and mid-IR interferometry. Pulsation properties and long-term variabilities were found from the near-IR light curves. The dust properties were determined using the DUSTY code which solves the radiative transfer. No changes in pulsational parameters were found, but a long-term variations with periods of 20-25 years have been detected which cannot be attributed to orbital motion.Circumstellar silicate dust shell with inner dust shell temperatures between 900 K and 1300 K and of moderate optical depth can explain all the observations. RR Tel showed the presence of an optically thin CS dust envelope and an optically thick dust region outside the line of sight, which was further supported by the detailed modelling using the 2D LELUYA code. Obscuration events in RR Tel were explained by an increase in optical depth caused by the newly condensed dust leading to the formation of a compact dust shell. HM Sge showed permanent obscuration and a presence of a compact dust shell with a variable optical depth. Scattering of the near-IR colours can be understood by a change in sublimation temperature caused by the Mira variability. Presence of large dust grains (up to 4 µm) suggests an increased grain growth in conditions of increased mass loss. The mass loss rates of up to 17·10-6 MSun/yr were significantly higher than in intermediate-period single Miras and in agreement with longer-period O-rich AGB stars.Despite the nova outburst, HM Sge remained enshrouded in dust with no significant dust destruction. The existence of unperturbed dust shell suggests a small influence of the hot component and strong dust shielding from the UV flux. By the use

  15. Dwarf Nova V1040 Centauri and Variable Stars in its Vicinity

    NASA Astrophysics Data System (ADS)

    Rutkowski, A.; Pietrukowicz, P.; Olech, A.; Ak, T.; Złoczewski, K.; Poleski, R.; Tappert, C.; Eker, Z.

    2011-12-01

    We present the results of a photometric campaign of the dwarf nova V1040 Cen. The light curve shows two normal outbursts with recurrence time ≍40 days and amplitude ≍2.5 mag. Quiescence data show oscillations with periods in the range ≍0.1 days (2.4 h) to ≍0.5 days (12 h) of unknown origin. We measured the orbital period of V1040 Cen to be Porb=0.060458(80) days (1.451±0.002 h). Based on the MV-Porb relation we found the distance of V1040 Cen to be 137±31 pc. In this paper we also report the detection of eleven new variable stars in the field of the monitored dwarf nova.

  16. Fine Guidance Sensor Parallaxes for Four Classical Novae

    NASA Astrophysics Data System (ADS)

    Harrison, Thomas

    2011-10-01

    Classical novae {CN} result from a thermonuclear runaway on a white dwarf and produce the second most violent stellar eruptions in the Galaxy. While we have made considerable progress on understanding the outbursts of these systems, numerous issues remain. We now have a general idea of what drives the peak luminosity of the outburst and the speed at which the CN declines from maximum {white dwarf mass}, but we have yet to properly calorimeter these outbursts due to the lack of precise distance information. More importantly, however, is understanding the mass lost during an eruption {could they be the progenitors of Type I supernovae?}. To quantify this, we need to know the volume and filling factor of their ejected shells. This requires accurate distance information, as CN produce clumpy, prolate shells. Four CN have archival FGS data {from 40 orbits!} that have yet to be properly reduced and analyzed. We propose to extract these data from the archive, and produce high precision {+/-10%} parallaxes. As shown by our team's track record, we have the expertise to complete this project during Cycle 19.

  17. Recurrent aphthous stomatitis

    PubMed Central

    Preeti, L; Magesh, KT; Rajkumar, K; Karthik, Raghavendhar

    2011-01-01

    Recurrent aphthous ulcers are common painful mucosal conditions affecting the oral cavity. Despite their high prevalence, etiopathogenesis remains unclear. This review article summarizes the clinical presentation, diagnostic criteria, and recent trends in the management of recurrent apthous stomatitis. PMID:22144824

  18. The Progenitors of Thermonuclear Supernovae

    SciTech Connect

    Piersanti, L.; Straniero, O.; Tornambe, A.; Dominguez, I.

    2009-05-03

    In the framework of the rotating Double Degenerate Scenario for type Ia Supernovae progenitors, we show that the dichotomy between explosive events in early and late type galaxies can be easily explained. Assuming that more massive progenitors produce slow-decline (high-luminosity) light curve, it comes out that, at the current age of the Universe, in late type galaxies the continuous star formation provides very massive exploding objects (prompt component) corresponding to slow-decline (bright) SNe; on the other hand, in early type galaxies, where star formation ended many billions years ago, only low mass ''normal luminosity'' objects (delayed component) are present.

  19. Subperiostial recurrence of chondroblastoma.

    PubMed

    Reddy, Sumanth; Deavers, Michael; Lin, Patrick; Haygood, Tamara Miner

    2009-01-01

    We present a case of subperiosteal recurrence of chondroblastoma adjacent to the greater trochanter that was initially thought to represent septic arthritis of the hip in a 10-year-old girl. Soft-tissue recurrence of chondroblastoma is very rare, with fewer than ten cases reported in the literature. We demonstrate the recurrence on both CT and MRI. The MRI clearly demonstrates the soft-tissue recurrence and the associated inflammatory changes, with signal characteristics not unlike the primary tumor. PMID:27307836

  20. A XMM-Newton Observation of Nova LMC 1995, a Bright Supersoft X-ray Source

    NASA Technical Reports Server (NTRS)

    Orio, Marina; Hartmann, Wouter; Still, Martin; Greiner, Jochen

    2003-01-01

    Nova LMC 1995, previously detected during 1995-1998 with ROSAT, was observed again as a luminous supersoft X-ray source with XMM-Newton in December of 2000. This nova offers the possibility to observe the spectrum of a hot white dwarf, burning hydrogen in a shell and not obscured by a wind or by nebular emission like in other supersoft X-ray sources. Notwithstanding uncertainties in the calibration of the EPIC instruments at energy E<0.5 keV, using atmospheric models in Non Local Thermonuclear Equilibrium we derived an effective temperature in the range 400,000-450,000 K, a bolometric luminosity Lbolabout equal to 2.3 times 10 sup37 erg s sup-l, and we verified that the abundance of carbon is not significantly enhanced in the X-rays emitting shell. The RGS grating spectra do not show emission lines (originated in a nebula or a wind) observed for some other supersoft X-ray sources. The crowded atmospheric absorption lines of the white dwarf cannot be not resolved. There is no hard component (expected from a wind, a surrounding nebula or an accretion disk), with no counts above the background at E>0.6 keV, and an upper limit Fx,hard = 10 sup-14 erg s sup-l cm sup-2 to the X-ray flux above this energy. The background corrected count rate measured by the EPIC instruments was variable on time scales of minutes and hours, but without the flares or sudden obscuration observed for other novae. The power spectrum shows a peak at 5.25 hours, possibly due to a modulation with the orbital period. We also briefly discuss the scenarios in which this nova may become a type Ia supernova progenitor.

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

    NASA Astrophysics Data System (ADS)

    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. NOVA laser facility for inertial confinement fusion

    SciTech Connect

    Simmons, W.W.

    1983-11-30

    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 ..mu..m) to its second (0.525 ..mu..m) or third (0.35 ..mu..m) harmonic. This additional capability (80 to 120 kJ at 0.525 ..mu..m, 40 to 70 kJ at 0.35 ..mu..m) was approved by the US 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.

  3. The distances of the Galactic Novae

    NASA Astrophysics Data System (ADS)

    Ozdonmez, Aykut; Guver, Tolga; Cabrera-Lavers, Antonio; Ak, Tansel

    2016-07-01

    Using location of the RC stars on the CMDs obtained from the UKIDSS, VISTA and 2MASS photometry, we have derived the reddening-distance relations towards each Galactic nova for which at least one independent reddening measurement exists. We were able to determine the distances of 72 Galactic novae and set lower limits on the distances of 45 systems. The reddening curves of the systems are presented. These curves can be also used to estimate reddening or the distance of any source, whose location is close to the position of the nova in our sample. The distance measurement method in our study can be easily applicable to any source, especially for ones that concentrated along the Galactic plane.

  4. The distances of the Galactic novae

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Utilizing the unique location of red clump giants on colour-magnitude diagrams obtained from various near-infrared 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 reddening-distance relations derived for each nova, which may be useful to analyse the different Galactic components present in the line of sight.

  5. AN EXTENDED GRID OF NOVA MODELS. III. VERY LUMINOUS, RED NOVAE

    SciTech Connect

    Shara, Michael M.; Zurek, David; Yaron, Ofer; Prialnik, Dina; Kovetz, Attay

    2010-12-10

    Extremely luminous, red eruptive variables like RV in M31 are being suggested as exemplars of a new class of astrophysical objects. Our greatly extended series of nova simulations shows that classical nova models can produce very red, luminous eruptions. In a poorly studied corner of three-dimensional nova parameter space (very cold, low-mass white dwarfs, accreting at very low rates) we find bona fide classical novae that are very luminous and red because they eject very slowly moving, massive envelopes. A crucial prediction of these nova models-in contrast to the predictions of merging star ('mergeburst') models-is that a hot remnant, the underlying white dwarf, will emerge after the massive ejected envelope has expanded enough to become optically thin. This blue remnant must fade on a timescale of decades-much faster than a 'mergeburst', which must fade on timescales of millennia or longer. Furthermore, the cooling nova white dwarf and its expanding ejecta must become redder in the years after eruption, while a contracting mergeburst must become hotter and bluer. We predict that red novae will always brighten to L {approx} 1000 L{sub sun} for about one year before rising to the maximum luminosity at L {approx} 10{sup 6}-10{sup 7} L{sub sun}. The maximum luminosity attainable by a nova is likely to be L {approx} 10{sup 7} L{sub sun}, corresponding to M {approx} -12. In an accompanying paper, we describe a fading, luminous blue candidate for the remnant of M31-RV; it is observed with the Hubble Space Telescope to be compatible only with the nova model.

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

    NASA Astrophysics Data System (ADS)

    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

  7. NUCLEAR MIXING METERS FOR CLASSICAL NOVAE

    SciTech Connect

    Kelly, Keegan J.; Iliadis, Christian; Downen, Lori; Champagne, Art; José, Jordi

    2013-11-10

    Classical novae are caused by mass transfer episodes from a main-sequence star onto a white dwarf via Roche lobe overflow. This material possesses angular momentum and forms an accretion disk around the white dwarf. Ultimately, a fraction of this material spirals in and piles up on the white dwarf surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds of megakelvin and explosively ejects matter into the interstellar medium. The exact peak temperature strongly depends on the underlying white dwarf mass, the accreted mass and metallicity, and the initial white dwarf luminosity. Observations of elemental abundance enrichments in these classical nova events imply that the ejected matter consists not only of processed solar material from the main-sequence partner but also of material from the outer layers of the underlying white dwarf. This indicates that white dwarf and accreted matter mix prior to the thermonuclear runaway. The processes by which this mixing occurs require further investigation to be understood. In this work, we analyze elemental abundances ejected from hydrodynamic nova models in search of elemental abundance ratios that are useful indicators of the total amount of mixing. We identify the abundance ratios ΣCNO/H, Ne/H, Mg/H, Al/H, and Si/H as useful mixing meters in ONe novae. The impact of thermonuclear reaction rate uncertainties on the mixing meters is investigated using Monte Carlo post-processing network calculations with temperature-density evolutions of all mass zones computed by the hydrodynamic models. We find that the current uncertainties in the {sup 30}P(p, γ){sup 31}S rate influence the Si/H abundance ratio, but overall the mixing meters found here are robust against nuclear physics uncertainties. A comparison of our results with observations of ONe novae provides strong constraints for classical nova models.

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

    SciTech Connect

    Levy, A.J.

    1983-11-30

    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.

  9. Terra Nova breaks new ground for alliances

    SciTech Connect

    Ghiselin, D.

    1996-08-01

    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.

  10. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Burwitz, V.; Pietsch, W.; Henze, M.; Rodriguez, J.; Haswell, C. A.; Holmes, S.; Kolb, U.; Lucas, R.

    2010-06-01

    We report the discovery of a possible nova in M 31 on a 5x120s stacked unfiltered CCD image obtained with the 0.35-m f/11 OU/OAM PIRATE Schmidt-Cassegrain telescope (+ SBIG STL-1001E CCD camera) at Costitx, Mallorca, Spain on 2010 June 26.084 UT with a corresponding R magnitude of 17.8. The position for the nova candidate is RA = 00h44m04.48s, Dec = +41d28'34.2" (J2000, accuracy of 0.3"), which is 902" east and 746" north of the core of M 31.

  11. PAH emission from Nova Cen 1986

    NASA Technical Reports Server (NTRS)

    Hyland, A. R. Harry; Mcgregor, P. J.

    1989-01-01

    The discovery of broad emission features between 3.2 and 3.6 microns were reported in the spectrum of Nova Cen 1986 (V842 Cen) some 300 days following outburst and remaining prominent for several months. The general characteristics of these features are similar to those attributed to polycyclic hydrocarbon (PAH) molecules in other dusty sources, although the relative strengths are different, and these observations provide the first clear evidence for molecular constituents other than graphite particles in the ejecta of novae.

  12. Mix experiments with the NOVA laser

    SciTech Connect

    Rupert, V.C.; Kilkenny, J.D.; Skokowski, P.G.

    1988-10-01

    The NOVA mix experiments are designed to study mix between two dissimilar materials subjected to strong (M/approximately/50) shocks and variable accelerations in a direction normal to their common boundary. The main purpose of the experiments is to provide a data base with which predictive models can be compared and normalized. Together with shock tube experiments, which explore a different regime, the current NOVA tests investigate the shock induced source terms in our model and the evolution of both Rayleigh-Taylor stable and unstable interfaces. 3 refs., 9 figs.

  13. Near Infrared Photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

    2013-08-01

    Subjects: Infra-Red, Nova We report RIJHKLM photometry of Nova Del 2013 taken on August 28.13 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) was used as the standard star. On this date we find: R = 5.6 +/- 0.1, I = 5.2 +/- 0.1, J = 4.5 +/- 0.1, H = 4.7 +/- 0.1, K = 4.7 +/- 0.1, L = 3.3 +/- 0.2, M = +1.8 +/- 0.3.

  14. The benefit of amateur observations for research in dwarf novae

    NASA Technical Reports Server (NTRS)

    La Dous, Constanze

    1992-01-01

    Contributions of amateur astronomers to research on dwarf novae, which are based on carefully monitoring the outburst behavior of these objects, are reviewed. These contributions range from scheduling of observations to the observational basis for research on the dwarf nova outburst mechanism. It is suggested, that, with better equipment, observations of orbital light variations in dwarf novae might be performed by amateur astronomers.

  15. Management of recurrent miscarriage.

    PubMed

    Sugiura-Ogasawara, Mayumi; Ozaki, Yasuhiko; Suzumori, Nobuhiro

    2014-05-01

    Recurrent miscarriage is classically defined as three or more consecutive pregnancy losses. Many researchers have now revised this definition to two or more pregnancy losses because of the recent increase in the prevalence of childless couples. Established causes of recurrent miscarriage are antiphospholipid antibodies, uterine anomalies and abnormal chromosomes in either partner, particularly translocations. Antiphospholipid syndrome is the most important treatable cause of recurrent miscarriage. However, it is not yet established as to what kind of testing should be conducted in patients with recurrent pregnancy loss. Standardization of tests for antiphospholipid antibodies is needed. On the other hand, embryonic aneuploidy is the most frequent cause of recurrent miscarriage. Chromosome analysis of the embryo is important, because it has good predictive value for subsequent live birth. It is not necessary to give any medications for unexplained cases of recurrent miscarriage, and provision of psychological support may be the most important to encourage the couples to continue to conceive until a live birth results.

  16. Nova outburst luminosities, postnova magnitude behaviour, and long term evolution of nova shell luminosities

    NASA Astrophysics Data System (ADS)

    Duerbeck, Hilmar W.

    2002-11-01

    A luminosity calibration of galactic novae indicates that all novae at brightness maximum radiate over-Eddington, and that speed- and light curve classes are intimately related. In later stages, the Balmer and [O III] line fluxes decline in similar ways for novae of all speed classes, except in slow ones where Balmer emission diminishes faster, and [O III] persists for decades. The brightness of the central source declines during the first century after outburst; decline rates for novae with orbital periods above 0.2 days are in good agreement with theoretical predictions, but there are indications that the luminosity will remain constant afterwards. Postnovae with shorter periods appear to decline more rapidly, and they often erupt from low-luminosity stages.

  17. Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis

    PubMed Central

    Patel, Keval; Griffing, George T.; Hauptman, Paul J.

    2016-01-01

    Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy. PMID:27127432

  18. Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis.

    PubMed

    Patel, Keval; Griffing, George T; Hauptman, Paul J; Stolker, Joshua M

    2016-04-01

    Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy. PMID:27127432

  19. PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS

    SciTech Connect

    Moriya, Takashi J.

    2012-05-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

  20. Progenitors of Recombining Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Moriya, Takashi J.

    2012-05-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

  1. NOVA[R] Spring 2002 Teacher's Guide.

    ERIC Educational Resources Information Center

    Armstrong, Peter; Ransick, Kristi; Rosene, Dale; Sammons, James

    The guide presents lesson plans from "NOVA" which targets middle school and junior high school students and meet the National Science Education Standards. Lessons include: (1) "Neanderthals on Trial"; (2) "Fireworks"; (3) "Secrets, Lies and Atomic Spies"; (4) "Bioterror"; (5) "The Missing Link"; (6) "Shackleton's Voyage of Endurance"; and (7)…

  2. The NOvA simulation chain

    DOE PAGES

    Aurisano, A.; Backhouse, C.; Hatcher, R.; Mayer, N.; Musser, J.; Patterson, R.; Schroeter, R.; Sousa, A.

    2015-12-23

    The NOvA experiment is a two-detector, long-baseline neutrino experiment operating in the recently upgraded NuMI muon neutrino beam. Simulating neutrino interactions and backgrounds requires many steps including: the simulation of the neutrino beam flux using FLUKA and the FLUGG interface, cosmic ray generation using CRY, neutrino interaction modeling using GENIE, and a simulation of the energy deposited in the detector using GEANT4. To shorten generation time, the modeling of detector-specific aspects, such as photon transport, detector and electronics noise, and readout electronics, employs custom, parameterized simulation applications. We will describe the NOvA simulation chain, and present details on the techniquesmore » used in modeling photon transport near the ends of cells, and in developing a novel data-driven noise simulation. Due to the high intensity of the NuMI beam, the Near Detector samples a high rate of muons originating in the surrounding rock. In addition, due to its location on the surface at Ash River, MN, the Far Detector collects a large rate ((˜) 140 kHz) of cosmic muons. Furthermore, we will discuss the methods used in NOvA for overlaying rock muons and cosmic ray muons with simulated neutrino interactions and show how realistically the final simulation reproduces the preliminary NOvA data.« less

  3. Stress and the Nova Scotia Teacher.

    ERIC Educational Resources Information Center

    Fergusson, Norman H.

    This study obtained information about the factors which cause stress for 406 teachers in Nova Scotia and determined possible differences by sub-groups. Noteworthy differences were found by size of school, gender, experience, type of school, administrator/non-administrator, and a few by license category. Results indicated that one teacher in four…

  4. The NOvA DAQ Monitor System

    NASA Astrophysics Data System (ADS)

    Baird, Michael; Grover, Deepika; Kasahara, Susan; Messier, Mark

    2015-12-01

    The NOvA (NuMI Off-Axis ve Appearance) experiment is a long-baseline neutrino experiment designed to search for vµ (v̅µ) to ve (v̅e) oscillations using Fermilab's NuMI main injector neutrino beam. The experiment consists of two detectors; both positioned 14 mrad off the beam axis: a 220 ton Near Detector constructed in an underground cavern at Fermilab and a 14 kton Far Detector constructed in Ash River, MN, 810 km from the beam source. The health and performance of the NOvA Data Acquisition (DAQ) system is monitored with a DAQ Monitor system based on the Ganglia distributed monitoring system, an open source third-party product which provides much of the NOvA DAQ monitoring needs “out-of-the-box”. This paper will discuss the use of the Ganglia system for this purpose, including augmentations we have made to the Ganglia base for the specific needs of our system. This paper will also discuss two other systems used to monitor the quality of the data collected by the NOvA detectors: an Online Monitoring system and Event Display, both of which leverage tools from the offline framework to provide close to real time diagnostic tools of detector performance.

  5. NOvA: Exploring Neutrino Mysteries

    ScienceCinema

    Vahle, Tricia; Messier, Mark

    2016-07-12

    Neutrinos are a mystery to physicists. They exist in three different flavors and mass states and may be able to give hints about the origins of the matter-dominated universe. A new long-baseline experiment led by Fermilab called NOvA may provide some answers.

  6. Creating healthy futures. 2000 NOVA Award winners.

    PubMed

    Larson, L

    2000-05-01

    Winners of this year's NOVA awards, sponsored by the American Hospital Association and H&HN magazine, all share a broad definition of health. These five stars of community benefit also understand that a community and a health care organization share responsibility for what creates health, and that collaborative efforts are the only way to sustain innovative programs. PMID:11785219

  7. Nova pulse power system description and status

    SciTech Connect

    Holloway, R.W.; Whitham, K.; Merritt, B.T.; Gritton, D.G.; Oicles, J.A.

    1981-06-01

    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.

  8. NOvA: Exploring Neutrino Mysteries

    SciTech Connect

    Vahle, Tricia; Messier, Mark

    2012-09-06

    Neutrinos are a mystery to physicists. They exist in three different flavors and mass states and may be able to give hints about the origins of the matter-dominated universe. A new long-baseline experiment led by Fermilab called NOvA may provide some answers.

  9. Nova Scotia. Reference Series No. 32.

    ERIC Educational Resources Information Center

    Department of External Affairs, Ottawa (Ontario).

    This booklet, one of a series featuring the Canadian provinces, presents a brief overview of Nova Scotia and is suitable for teacher reference or student reading. Separate sections discuss the geography and climate, history, economic development, fishing, agriculture, forestry, mining, manufacturing, energy, education, arts and culture, and…

  10. Status of the NOvA experiment

    SciTech Connect

    Plunkett, Robert; /Fermilab

    2007-12-01

    The NOvA experiment, using the existing NuMI beamline, is planned for construction at Ash River, Minnesota. The experiment will provide a measurement of, or strong limit on the neutrino mixing angle {theta}{sub 13}, and for sufficiently strong mixing, establish the hierarchy of the neutrino masses.

  11. Engineering the Petawatt Laser into Nova

    SciTech Connect

    Tietbohl, G.L.; Bell, P.M.; Hamilton, R.M.

    1997-12-23

    The engineering process of integrating the Petawatt (10{sup 15} watts) laser system into the existing 30 kJ (UV) Nova laser at Lawrence Livermore National Laboratory (LLNL) is described in detail. The nanosecond-long, chirped Petawatt laser pulse is initially generated in a separate master oscillator room and then injected into one of Nova`s 10 beamlines. There, the pulse is further amplified and enlarged to {approximately}{phi}60 cm, temporally compressed under vacuum to <500 fs using large diameter diffraction gratings, and then finally focused onto targets using a parabolic mirror. The major Petawatt components are physically large which created many significant engineering challenges in design, installation and implementation. These include the diffraction gratings and mirrors, vacuum compressor chamber, target chamber, and parabolic focusing mirror. Other Petawatt system components were also technically challenging and include: an injection beamline, transport spatial filters, laser diagnostics, alignment components, motor controls, interlocks, timing and synchronization systems, support structures, and vacuum systems. The entire Petawatt laser system was designed, fabricated, installed, and activated while the Nova laser continued its normal two-shift operation. This process required careful engineering and detailed planning to prevent experimental downtime and to complete the project on schedule.

  12. The expanding fireball of Nova Delphini 2013.

    PubMed

    Schaefer, G H; ten Brummelaar, T; 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

    2014-11-13

    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 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 as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun. PMID:25363778

  13. Numerical modelling of the classical nova outburst

    SciTech Connect

    Kutter, G.S.; Sparks, W.M.

    1987-01-01

    We describe a mechanism that promises to explain how nova outbursts take place on white dwarf of 1 Msub solar or less and for accretion rates of 4 x 10/sup -10/ Msub solar yr/sup -1/ or greater. 7 refs.

  14. NOVA[R] Fall 2001 Teacher's Guide.

    ERIC Educational Resources Information Center

    WGBH-TV, Boston, MA.

    This teacher guide includes activity information for the program NOVA, Fall 2001. Background for each activity is provided along with its correlation to the national science standards. Activities include: (1) "Search for a Safe Cigarette"; (2) "18 Ways To Make a Baby"; (3) "Secrets of Mind"; (4) "Neanderthals on Trial"; (5) "Life's Greatest…

  15. NOVA[R] Spring 2001 Teacher's Guide.

    ERIC Educational Resources Information Center

    WGBH-TV, Boston, MA.

    This teacher's guide is designed to accompany the PBS television program "NOVA" and features six activities. "Sultan's Lost Treasure" presents the attempts of an archaeologist and his team to salvage an ancient ship wreck. "Vanished!" investigates what happened to the Stardust airliner in 1947 which disappeared during a flight. "Lost King of the…

  16. Nova Sct 2009 (V496 Sct)

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2009-11-01

    As initially announced in CBET 2008 (Daniel W. E. Green, ed.) and AAVSO Special Notice #176 (M. Templeton), and expanded on in IAU Circular No. 9093 (Green, ed.), Nova Scutum 2009 (V496 Sct) was discovered by H. Nishimura (Miyawaki, Kakegawa, Japan) on 2009 November 8.370 UT at unfiltered CCD magnitude of 8.8, using 120-mm camera lens, derived by S. Nakano (Sumoto, Japan) from Nishimura's discovery images. RA: 18:43:45.57 , Dec: -7:36:42.0 (equinox 2000.0) from E. Guido and G. Sostero. Spectroscopy by F. Teyssier (Rouen, France); D. Balam (NRCC) and G. Sarty (U. Sask.); and U. Munari et al. (INA-Padova & the Asiago Novae and Symbiotic Stars Collaboration) confirm the object as a nova, with emission lines showing P Cygni profiles. Munari et al. show the presence of FeII, indicating a nova of the Fe II-type. Observations should be reported to the AAVSO International Database as V496 SCO.

  17. Supernova hydrodynamicas experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.

    1997-07-01

    We are developing experiments using the Nova laser to investigate (1) compressible nonlinear hydrodynamic mixing relevant to the first few hours of the supernova (SN) explosion and (2) ejecta-ambient plasma interactions relevant to the early SN remnant phase. The experiments and astrophysical implications are discussed.

  18. Near Infrared Photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Cass, A. C.; Carlon, R. L.; Corgan, D. T.; Dykhoff, D. A.; Gehrz, R. D.; Shenoy, D. P.

    2013-09-01

    We continued to follow Nova Del 2013 during the period from 31.15 August 2013 UT through 25.18 September 2013 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) is used as the standard star.

  19. NEVEC: the NOVA ESO VLTI Expertise Center

    NASA Astrophysics Data System (ADS)

    Le Poole, Rudolf S.; Miley, George; Jaffe, Walter; Glindemann, Andreas; Bakker, Eric J.; Waters, Rens; Roettgering, Huub J. A.; Cotton, Bill; Percheron, Isabelle; Meisner, Jeffrey A.; de Jong, Jeroen; D'Arcio, Luigi; Heijligers, Bjoern

    2003-02-01

    The start of NEVEC was initiated by the opportunity in the Netherlands to reinstate instrumental efforts in astronomy through a funding program for 'Top Research Schools,’ which brought about the creation of NOVA. The fact that considerable experience exists in Radio Astronomical imaging through interferometry (the Westerbork Synthesis Radio Telescope started in 1970), and the relatively small size at the time of ESO's VLTI Team made it opportune to aim for a win-win situation through collaboration. So presently an MOU between ESO and NOVA is in force, which stipulates that 10 out of the 18 man-years funded by NOVA for NEVEC until 2005 [new personnel, in university setting (Leiden) but on project money] shall be used on tasks that are mutually agreed between NOVA and ESO. The tasks presently are found in the domain of observing modes, calibration and modeling, as well as contributing to the commissioning of new instruments and thinking about future instruments. Another task, outside these 10 FTE, has been the data handling and analysis software for MIDI, and again contributing to its commissioning. Delivery of the first operational version in Heidelberg has just taken place (summer 2002) contributing to the successful Preliminary Acceptance in Europe for MIDI on September 10, 2002. The actual state of 'products and deliveries' and the future outlook are reviewed.

  20. FUSE Observations of Galactic and LMC Novae in Outburst

    NASA Technical Reports Server (NTRS)

    Huschildt, P. H.

    2001-01-01

    This document is a collection of five abstracts from papers written on the 'FUSE Observations of Galactic and LMC Novae in Outburst'. The titles are the following: (1) Analyzing FUSE Observations of Galactic and LMC Novae; (2) Detailed NLTE Model Atmospheres for Novae during Outburst: Modeling Optical and Ultraviolet Observations for Nova LMC 1988; (3) Numerical Solution of the Expanding Stellar Atmosphere Problem; (4) A Non-LTE Line-Blanketed Expanding Atmosphere Model for A-supergiant Alpha Cygni; and (5) Non-LTE Model Atmosphere Analysis of the Early Ultraviolet Spectra of Nova Andromedae 1986. A list of journal publications is also included.

  1. NOVA making stuff: Season 2

    SciTech Connect

    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

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

    PubMed

    Tajitsu, Akito; Sadakane, Kozo; Naito, Hiroyuki; Arai, Akira; Aoki, Wako

    2015-02-19

    The origin of lithium (Li) and its production process have long been uncertain. Li could be produced by 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 the Li may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. No direct evidence, however, for the supply of Li from evolved stellar objects to the Galactic medium has hitherto been found. Here we report the detection of highly blue-shifted resonance lines of the singly ionized radioactive isotope of beryllium, (7)Be, in the near-ultraviolet spectra of the classical nova V339 Del (Nova Delphini 2013) 38 to 48 days after the explosion. (7)Be decays to form (7)Li within a short time (half-life of 53.22 days). The (7)Be was created during the nova explosion via the alpha-capture reaction (3)He(α,γ)(7)Be (ref. 5). This result supports the theoretical prediction that a significant amount of (7)Li is produced in classical nova explosions. PMID:25693569

  3. THE DWARF NOVA OUTBURSTS OF NOVA HER 1960 (=V446 HER)

    SciTech Connect

    Honeycutt, R. K.; Robertson, J. W.; Kafka, S. E-mail: jrobertson@atu.edu

    2011-04-15

    V446 Her is the best example of an old nova which has developed dwarf nova (DN) eruptions in the post-nova state. We report on observed properties of the long-term light curve of V446 Her, using photometry over 19 years. Yearly averages of the outburst (OB) magnitudes show a decline of {approx}0.013 mag yr{sup -1}, consistent with the decline of other post-novae that do not have DN OBs. Previous suggestions of bimodal distributions of the amplitudes and widths of the OBs are confirmed. The OBs occur at a mean spacing of 18 days but the range of spacings is large (13-30 days). From simulations of DN OBs, it has been predicted that the OB spacing in V446 Her will increase as M-dot from the red dwarf companion slowly falls following the nova; however, the large intrinsic scatter in the spacings serves to hide any evidence of this effect. We do find a systematic change in the OB pattern in which the brighter, wider type of OBs disappeared after late 2003, and this phenomenon is suggested to be due to falling M-dot following the nova.

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

    PubMed

    Tajitsu, Akito; Sadakane, Kozo; Naito, Hiroyuki; Arai, Akira; Aoki, Wako

    2015-02-19

    The origin of lithium (Li) and its production process have long been uncertain. Li could be produced by 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 the Li may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. No direct evidence, however, for the supply of Li from evolved stellar objects to the Galactic medium has hitherto been found. Here we report the detection of highly blue-shifted resonance lines of the singly ionized radioactive isotope of beryllium, (7)Be, in the near-ultraviolet spectra of the classical nova V339 Del (Nova Delphini 2013) 38 to 48 days after the explosion. (7)Be decays to form (7)Li within a short time (half-life of 53.22 days). The (7)Be was created during the nova explosion via the alpha-capture reaction (3)He(α,γ)(7)Be (ref. 5). This result supports the theoretical prediction that a significant amount of (7)Li is produced in classical nova explosions.

  5. Nova eruption in V407 Cyg

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2010-03-01

    According to CBET 2199, 2204, and 2205 (D.W.E. Green, ed. of all three), the suspected symbiotic star V407 Cyg has been observed in an anomalously bright outburst, and subsequent spectroscopic observations by multiple observers show clear signs of a classical nova. Observations of this anomalous event are requested immediately, and observers are asked to continue observing this object until it returns to its previous quiescent level. V407 Cyg was independently discovered in bright outburst by four sets of observers: K. Nishiyama (Fukuoka, Japan) and F. Kabashima (Saga, Japan) at magnitude 7.4 unfiltered on 2010 March 10.797 UT; K. Tsumagoi (Agatsuma-gun, Gunma-ken, Japan) at magnitude ~7 on 2010 March 11.789 UT; K. Sakaniwa (Higashichikumagun, Nagano, Japan) at magnitude 7.4 on 2010 March 11.8 UT; A. Tago (Tsuyama, Okayama-ken, Japan) at ~7th magnitude on 2010 March 11.815 UT. Spectroscopy by Munari et al. on 2010 March 13.09 UT indicates a peculiar composite spectrum with evidence for a classical nova in progress, namely broad emission lines with FWHM of 2300 km/s. Such high velocities cannot occur in symbiotic stars, and so the current eruption appears to be a nova outburst in progress. Low resolution spectra also showing signs of a nova eruption were obtained by several observers. In summary, the evidence points to a classical nova eruption of a symbiotic star. The system is further complicated by the fact that the donor star in the system is likely a variable of Mira type. All observations of this complex and interesting system, including visual estimates, CCD time series, and multicolor photometry are strongly encouraged. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  6. The NOvA software testing framework

    NASA Astrophysics Data System (ADS)

    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.

  7. Evolution of the stellar-merger red nova V1309 Scorpii: Spectral energy distribution analysis

    NASA Astrophysics Data System (ADS)

    Tylenda, R.; Kamiński, T.

    2016-08-01

    Context. 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. Aims: We will study the evolution of the post-merger remnant of V1309 Sco over time. Methods: 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. Results: 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 completely embedded in dust. The parameters (temperature, dimensions) of the dusty envelope in 2010 and 2012 evidence that we then observed matter lost by the object during the 2008 outburst. Its mass is at least 10-3M⊙. The object remains quite luminous, although since its maximum brightness in September 2008, it has faded in luminosity by a factor of ~50 (in 2012). Far infrared data from Herschel reveal presence of a cold (~30 K) dust at a distance of a few thousand AU from the object. Conclusions: Similarly to other red novae, V1309 Sco formed a slowly-expanding, dense, and optically-thick dusty envelope during its 2008 outburst. The main remnant is thus hidden for us. Far infrared data suggests that the object passed an episode of intense mass loss in its recent history. This conclusion could be verified by submillimeter interferometric observations.

  8. Microchimerism in recurrent miscarriage.

    PubMed

    Gammill, Hilary S; Stephenson, Mary D; Aydelotte, Tessa M; Nelson, J Lee

    2014-11-01

    Maternal-fetal cell exchange during pregnancy results in acquisition of microchimerism, which can durably persist in both recipients. Naturally acquired microchimerism may impact maternal-fetal interaction in pregnancy. We conducted studies to ask whether microchimerism that a woman acquired from her own mother is detectable before or during pregnancy in women with recurrent miscarriage. Fetal microchimerism was also assayed. Women with primary idiopathic recurrent miscarriage (n=23) and controls (n=31) were studied. Genotyping was conducted for probands, their mothers and the fetus, a non-shared polymorphism identified and quantitative polymerase chain reaction performed to measure microchimerismin peripheral blood mononuclear cells. Preconception comparisons were made between recurrent miscarriage subjects and controls, using logistic regression and Wilcoxon rank sum. Longitudinal microchimerism in subsequent pregnancies of recurrent miscarriage subjects was described. There was a trend toward lower preconception detection of microchimerism in recurrent miscarriage versus controls, 6% vs. 19% (1/16 vs. 6/31, P=0.2). During pregnancy, 3/11 (27%) of recurrent miscarriage subjects who went on to have a birth had detection of microchimerism from their own mother, whereas neither of two subjects who went on to miscarry had detection (0/2). This initial data suggest that microchimerism from a woman's own mother, while detectable in women with recurrent miscarriage, may differ from controls and according to subsequent pregnancy outcome. Further studies are needed to determine the cell types, quantities and any potential functional role of microchimerism in recurrent miscarriage.

  9. Recurrent mixed tumor.

    PubMed

    Batsakis, J G

    1986-01-01

    Recurrence of benign neoplasms can usually be attributed to incomplete excision. Such is the case with benign mixed tumors of salivary glands. Certain histopathologic features of mixed tumors, however, appear to facilitate recurrences. These are: a predominantly myxoid composition, and transcapsular extension by the tumor. Multicentric origin is possible, but it must be regarded as a much lower order of probability.

  10. Pan-chromatic observations of the remarkable nova Large Magellanic Cloud 2012

    SciTech Connect

    Schwarz, Greg J.; Shore, Steven N.; Page, Kim L.; Osborne, Julian P.; Beardmore, Andrew P.; Walter, Frederick M.; Bode, Michael F.; Drake, Jeremy J.; Ness, Jan-Uwe; Starrfield, Sumner; Rossum, Daniel R. Van; Woodward, Charles E.

    2015-03-01

    We present the results of an intensive multiwavelength campaign on nova LMC 2012. This nova evolved very rapidly in all observed wavelengths. The time to fall two magnitudes in the V band was only 2 days. In X-rays the super soft phase began 13 ± 5 days after discovery and ended around day 50 after discovery. During the super soft phase, the Swift/XRT and Chandra spectra were consistent with the underlying white dwarf (WD) being very hot, ∼1 MK, and luminous, ∼10{sup 38} erg s{sup −1}. The UV, optical, and near-IR photometry showed a periodic variation after the initial and rapid fading had ended. Timing analysis revealed a consistent 19.24 ± 0.03 hr period in all UV, optical, and near-IR bands with amplitudes of ∼0.3 mag which we associate with the orbital period of the central binary. No periods were detected in the corresponding X-ray data sets. A moderately high inclination system, i = 60 ± 10{sup ∘}, was inferred from the early optical emission lines. The HST/STIS UV spectra were highly unusual with only the N v (1240 Å) line present and superposed on a blue continuum. The lack of emission lines and the observed UV and optical continua from four epochs can be fit with a low mass ejection event, ∼10{sup −6} M{sub ⊙}, from a hot and massive WD near the Chandrasekhar limit. The WD, in turn, significantly illuminated its subgiant companion which provided the bulk of the observed UV/optical continuum emission at the later dates. The inferred extreme WD characteristics and low mass ejection event favor nova LMC 2012 being a recurrent nova of the U Sco subclass.

  11. Pan-Chromatic Observations of the Remarkable Nova Large Magellanic Cloud 2012

    NASA Astrophysics Data System (ADS)

    Schwarz, Greg J.; Shore, Steven N.; Page, Kim L.; Osborne, Julian P.; Beardmore, Andrew P.; Walter, Frederick M.; Bode, Michael F.; Drake, Jeremy J.; Ness, Jan-Uwe; Starrfield, Sumner; Van Rossum, Daniel R.; Woodward, Charles E.

    2015-03-01

    We present the results of an intensive multiwavelength campaign on nova LMC 2012. This nova evolved very rapidly in all observed wavelengths. The time to fall two magnitudes in the V band was only 2 days. In X-rays the super soft phase began 13 ± 5 days after discovery and ended around day 50 after discovery. During the super soft phase, the Swift/XRT and Chandra spectra were consistent with the underlying white dwarf (WD) being very hot, ˜1 MK, and luminous, ˜1038 erg s-1. The UV, optical, and near-IR photometry showed a periodic variation after the initial and rapid fading had ended. Timing analysis revealed a consistent 19.24 ± 0.03 hr period in all UV, optical, and near-IR bands with amplitudes of ˜0.3 mag which we associate with the orbital period of the central binary. No periods were detected in the corresponding X-ray data sets. A moderately high inclination system, i = 60 ± 10{\\circ{}}, was inferred from the early optical emission lines. The HST/STIS UV spectra were highly unusual with only the N v (1240 Å) line present and superposed on a blue continuum. The lack of emission lines and the observed UV and optical continua from four epochs can be fit with a low mass ejection event, ˜10-6 {{M}⊙ }, from a hot and massive WD near the Chandrasekhar limit. The WD, in turn, significantly illuminated its subgiant companion which provided the bulk of the observed UV/optical continuum emission at the later dates. The inferred extreme WD characteristics and low mass ejection event favor nova LMC 2012 being a recurrent nova of the U Sco subclass. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

  12. Modeling renal progenitors - defining the niche.

    PubMed

    Tanigawa, Shunsuke; Perantoni, Alan O

    2016-01-01

    Significant recent advances in methodologies for the differentiation of pluripotent stem cells to renal progenitors as well as the definition of niche conditions for sustaining those progenitors have dramatically enhanced our understanding of their biology and developmental programing, prerequisites for establishing viable approaches to renal regeneration. In this article, we review the evolution of culture techniques and models for the study of metanephric development, describe the signaling mechanisms likely to be driving progenitor self-renewal, and discuss current efforts to generate de novo functional tissues, providing in depth protocols and niche conditions for the stabilization of the nephronic Six2+progenitor. PMID:26856661

  13. The awakening of a classical nova from hibernation

    NASA Astrophysics Data System (ADS)

    Mróz, Przemek; Udalski, Andrzej; Pietrukowicz, Paweł; Szymański, Michał K.; Soszyński, Igor; Wyrzykowski, Łukasz; Poleski, Radosław; Kozłowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; Skowron, Dorota; Pawlak, Michał

    2016-09-01

    Cataclysmic variable stars—novae, dwarf novae, and nova-likes—are close binary systems consisting of a white dwarf star (the primary) that is accreting matter from a low-mass companion star (the secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, with a ten-thousandfold increase 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 ten thousand to a million years. In between, the system’s properties depend primarily on the mass-transfer rate: if it is lower than a billionth of a solar mass per 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 in the binary, keeping it high for centuries after the event. Subsequently, the mass-transfer rate should significantly decrease for a thousand to a million years, starting the hibernation phase. After that the nova awakes again—with accretion returning to the pre-eruption level and leading to a new nova explosion. The hibernation model predicts cyclical evolution of cataclysmic variables through phases of high and low mass-transfer. The theory gained some support from the discovery of ancient nova shells around the dwarf novae Z Camelopardalis and AT Cancri, but direct evidence for considerable mass-transfer changes prior, during and after nova eruptions has not hitherto been found. Here we report long-term observations of the classical nova V1213 Cen (Nova Centauri 2009) covering its pre- and post-eruption phases and precisely documenting its evolution. Within the six years before the explosion, the system revealed dwarf nova outbursts indicative of a low mass-transfer rate. The post-nova is two orders of magnitude brighter than the pre-nova at minimum light with no trace of

  14. Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro

    PubMed Central

    2013-01-01

    Background Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. Methods The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. Results The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Conclusions Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma. PMID:23915425

  15. A luminous, blue progenitor system for the type Iax supernova 2012Z.

    PubMed

    McCully, Curtis; Jha, Saurabh W; Foley, Ryan J; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P; Marion, G H; Riess, Adam G; Stritzinger, Maximilian D

    2014-08-01

    Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are 'less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star. PMID:25100479

  16. A luminous, blue progenitor system for the type Iax supernova 2012Z.

    PubMed

    McCully, Curtis; Jha, Saurabh W; Foley, Ryan J; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P; Marion, G H; Riess, Adam G; Stritzinger, Maximilian D

    2014-08-01

    Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are 'less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

  17. Predictors of Recurrent AKI.

    PubMed

    Siew, Edward D; Parr, Sharidan K; Abdel-Kader, Khaled; Eden, Svetlana K; Peterson, Josh F; Bansal, Nisha; Hung, Adriana M; Fly, James; Speroff, Ted; Ikizler, T Alp; Matheny, Michael E

    2016-04-01

    Recurrent AKI is common among patients after hospitalized AKI and is associated with progressive CKD. In this study, we identified clinical risk factors for recurrent AKI present during index AKI hospitalizations that occurred between 2003 and 2010 using a regional Veterans Administration database in the United States. AKI was defined as a 0.3 mg/dl or 50% increase from a baseline creatinine measure. The primary outcome was hospitalization with recurrent AKI within 12 months of discharge from the index hospitalization. Time to recurrent AKI was examined using Cox regression analysis, and sensitivity analyses were performed using a competing risk approach. Among 11,683 qualifying AKI hospitalizations, 2954 patients (25%) were hospitalized with recurrent AKI within 12 months of discharge. Median time to recurrent AKI within 12 months was 64 (interquartile range 19-167) days. In addition to known demographic and comorbid risk factors for AKI, patients with longer AKI duration and those whose discharge diagnosis at index AKI hospitalization included congestive heart failure (primary diagnosis), decompensated advanced liver disease, cancer with or without chemotherapy, acute coronary syndrome, or volume depletion, were at highest risk for being hospitalized with recurrent AKI. Risk factors identified were similar when a competing risk model for death was applied. In conclusion, several inpatient conditions associated with AKI may increase the risk for recurrent AKI. These findings should facilitate risk stratification, guide appropriate patient referral after AKI, and help generate potential risk reduction strategies. Efforts to identify modifiable factors to prevent recurrent AKI in these patients are warranted.

  18. Discovery of an eclipsing dwarf nova in the ancient nova shell Te 11

    NASA Astrophysics Data System (ADS)

    Miszalski, Brent; Woudt, P. A.; Littlefair, S. P.; Warner, B.; Boffin, H. M. J.; Corradi, R. L. M.; Jones, D.; Motsoaledi, M.; Rodríguez-Gil, P.; Sabin, L.; Santander-García, M.

    2016-02-01

    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⊙ 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.

  19. Tycho Brahe and the Nova of 1572

    NASA Astrophysics Data System (ADS)

    Gingerich, O.

    2005-12-01

    The brilliant Nova of 1572 marked the beginning of the end of Aristotelian cosmology and provided the defining moment when the young Tycho Brahe became a professional astronomer. He received more than a ton of gold from the Danish king to build his Uraniborg Observatory. His instruments, the finest produced in the pre-telescopic age, enabled him to establish that both the nova and the Comet of 1577 lay beyond the moon, contrary to Aristotle's teaching. His major attempt to establish the distance to Mars (in order to distinguish between the Ptolemaic and Copernican cosmologies) failed, but left in its wake a magnificently accurate set of data that enabled Kepler to make the greatest advance in celestial mechanics since Copernicus himself.

  20. Seismic upgrade of the Nova capacitor bank

    SciTech Connect

    Tietbohl, G.L.; Patel, C.S.

    1993-04-05

    The main capacitor bank for the Nova laser system at Lawrence Livermore National Laboratory was found to be seismically unsafe after the 1989 Loma Prieta earthquake. A method of strengthening the bank was developed, which satisfied the current seismic design criteria and minimized the downtime of the laser system during installation. Before implementation, the design was analyzed by finite element methods and the building was checked for load capacity. The bank is now upgraded to current seismic standards.

  1. 1729-19 Nova Ophiuchi 1994

    NASA Astrophysics Data System (ADS)

    Mattei, Janet A.

    1994-06-01

    Akihiko Tago and Minoru Yamamoto discover an apparent nova in Ophiuchus at mag. 7.0. Position RA 17h 32m 47.56" DEC -19° 17' 41.8". TV Crv is in outburst with current magnitude estimates approximating 13.0. An error was made reporting a bright outburst of UV Per in Alert Notice 186 and should be ignored. The star continues to be bright, however, with estimates approximating 12.5.

  2. Nova power systems: status and operating experience

    SciTech Connect

    Whitham, K.; Merritt, B.T.; Gritton, D.G.; Smart, A.J.; Holloway, R.W.; Oicles, J.A.

    1983-11-28

    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.

  3. Introduction to the Nova technical contract

    SciTech Connect

    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.

  4. Dwarf Nova Outbursts with Magnetorotational Turbulence

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    The phenomenological Disc Instability Model has been successful in reproducing the observed light curves of dwarf nova outbursts by invoking an enhanced Shakura-Sunyaev α parameter ˜0.1 - 0.2 in outburst compared to a low value ˜0.01 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 α in discs in outburst, but only near the hydrogen ionization transition. At higher temperatures, convection no longer exists and α 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 α into the Disc Instability Model, as well as simulation-based models of turbulent dissipation and convective transport. These MRI-based models can successfully reproduce observed outburst and quiescence durations, as well as outburst amplitudes, albeit with different parameters from the standard Disc Instability Models. The MRI-based model lightcurves exhibit reflares in the decay from outburst, which are not generally observed in dwarf novae. However, we highlight the problematic aspects of the quiescence physics in the Disc Instability Model and MRI simulations that are responsible for this behavior.

  5. Dwarf nova outbursts with magnetorotational turbulence

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    The phenomenological disc instability model has been successful in reproducing the observed light curves of dwarf nova outbursts by invoking an enhanced Shakura-Sunyaev α parameter ˜0.1-0.2 in outburst compared to a low value ˜0.01 in quiescence. Recent thermodynamically consistent simulations of magnetorotational instability (MRI) turbulence with appropriate opacities and equation of state for dwarf nova accretion discs have found that thermal convection enhances α in discs in outburst, but only near the hydrogen ionization transition. At higher temperatures, convection no longer exists and α 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 α into the disc instability model, as well as simulation-based models of turbulent dissipation and convective transport. These MRI-based models can successfully reproduce observed outburst and quiescence durations, as well as outburst amplitudes, albeit with different parameters from the standard disc instability models. The MRI-based model light curves exhibit reflares in the decay from outburst, which are not generally observed in dwarf novae. However, we highlight the problematic aspects of the quiescence physics in the disc instability model and MRI simulations that are responsible for this behaviour.

  6. Recurrent pregnancy loss.

    PubMed

    Rao, Kamini A; Pillai, Jyothi R

    2006-08-01

    Recurrent abortions are hisheartening to the couple and also to the treating clinicians. Miscarriage is the loss of pregnancy weighing 500 g or less. Recurrent miscarriage or habitual abortion is defined as three or more consective abortions. Important factors involved in recurrent early pregnancy loss are genetic factors, endocrine factors, anatomic factors, immunologic factors, infectious factors and environmental factors. The factors are described in a nutshell in the text. Any severe infection that leads to bacteraemia orviraemia can cause sporadic miscarriage. Congenital uterine abnormalities have been associated most often with second-trimestar pregnancy loss. As regarding management of recurrent pregnancy loss the clinician has limited options. The use of aspiration in low dose (75 mg) and heparin is beneficial in APS positive patients. Multivitamins and folic acid assume importance in thrombophilic disorders. Tender live care with regular antenatal check-ups go a great way in achieving live term pregnancy.

  7. Integration of the Super Nova early warning system with the NOvA Trigger

    SciTech Connect

    Habig, Alec; Zirnstein, Jan

    2015-01-01

    The NOvA experiment, with a baseline of 810km, samples Fermilab’s upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14 kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into our trigger. In conclusion, this presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.

  8. Integration of the Super Nova early warning system with the NOvA Trigger

    DOE PAGES

    Habig, Alec; Zirnstein, Jan

    2015-01-01

    The NOvA experiment, with a baseline of 810km, samples Fermilab’s upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14 kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into ourmore » trigger. In conclusion, this presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.« less

  9. Integration of the Super Nova Early Warning System with the NOvA Trigger

    NASA Astrophysics Data System (ADS)

    Habig, Alec; Zirnstein, Jan

    2015-12-01

    The NOvA experiment, with a baseline of 810km, samples Fermilab's upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into our trigger. This presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.

  10. Nova in Sagittarius (V5586 Sgr = Nova Sgr 2010 No. 2)

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2010-04-01

    The discovery is announced of Nova Sgr 2010 No. 2 = V5586 Sgr by Koichi Nishiyama (Kurume, Japan) and Fujio Kabashima (Miyaki, Japan) on 2010 Apr. 23.782 UT at unfiltered CCD magnitude 11.2. Spectra by L. A. Helton et al. on Apr. 25.4 UT confirm that V5586 Sgr is a post-maximum classical nova subjected to an exceptionally high degree of extinction. The red spectrum is similar to that of Nova Pup 1991 (V351 Pup; Williams et al. 1994, Ap.J. Suppl. 90, 297). Initially announced in CBET 2261 (Daniel W. E. Green, ed.), with additional information in CBET 2264 (Daniel W. E. Green, ed.). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  11. NovaNet Student Outcomes, 2001-2002.

    ERIC Educational Resources Information Center

    Harlow, Kristin; Baenen, Nancy

    NovaNet is an individualized, computer-based instruction program that is used in the Wake County Public School System (WCPSS), North Carolina, for high school course credit, remediation, and enrichment. NovaNet was first used in WCPSS in 1996, and in 1999 WCPSS received a 3-year federal grant to expand the use of NovaNET to all high schools. In…

  12. Hohlraum drive and implosion experiments on Nova. Revision 1

    SciTech Connect

    Kilkenny, J.D.; Suter, L.J.; Cable, M.D.

    1994-09-08

    Experiments on Nova have demonstrated hohlraum radiation temperatures up to 300 eV and in lower temperature experiments reproducible time integrated symmetry to 1--2%. Detailed 2-D LASNEX simulations satisfactorily reproduce Nova`s drive and symmetry scaling data bases. Hohlraums has been used for implosion experiments achieving convergence ratios (initial capsule radius/final fuel radius) up to 24 with high density glass surrounding a hot gas fill.

  13. Optical and EUV light curves of dwarf nova outbursts

    SciTech Connect

    Mauche, C W; Mattei, J A; Bateson, F M

    2000-11-15

    We combine AAVSO and VSS/RASNZ optical and Extreme Ultraviolet Explorer EUV light curves of dwarf novae in outburst to place constraints on the nature of dwarf nova outbursts. From the observed optical-EUV time delays of {approx} 0.75-1.5 days, we show that the propagation velocity of the dwarf nova instability heating wave is {approx} 3 km s{sup -1}.

  14. The UBV Color Evolution of Classical Novae. I. Nova-giant Sequence in the Color-Color Diagram

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2014-04-01

    We identified a general course of classical nova outbursts in the B - V versus U - B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and near-maximum phases, which we call "the nova-giant sequence." This sequence is parallel to but Δ(U - B) ≈ -0.2 mag bluer than the supergiant sequence. This is because the mass of a nova envelope is much (~10-4 times) less than that of a normal supergiant. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B - V = -0.03, U - B = -0.97), which coincides with the intersection of the blackbody sequence and the nova-giant sequence, and remains there for a while. Then the color evolves leftward (blueward in B - V but almost constant in U - B), owing mainly to the development of strong emission lines. This is the general course of nova outbursts in the color-color diagram, which was deduced from eight well-observed novae in various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining the color excesses of classical novae. Using this method, we redetermined the color excesses of 20 well-observed novae. The obtained color excesses are in reasonable agreement with the previous results, which in turn support the idea of our general track of nova outbursts. Additionally, we estimated the absolute V magnitudes of about 30 novae using a method for time-stretching nova light curves to analyze the distance-reddening relations of the novae.

  15. The UBV color evolution of classical novae. I. Nova-giant sequence in the color-color diagram

    SciTech Connect

    Hachisu, Izumi; Kato, Mariko E-mail: mariko@educ.cc.keio.ac.jp

    2014-04-20

    We identified a general course of classical nova outbursts in the B – V versus U – B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and near-maximum phases, which we call 'the nova-giant sequence'. This sequence is parallel to but Δ(U – B) ≈ –0.2 mag bluer than the supergiant sequence. This is because the mass of a nova envelope is much (∼10{sup –4} times) less than that of a normal supergiant. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B – V = –0.03, U – B = –0.97), which coincides with the intersection of the blackbody sequence and the nova-giant sequence, and remains there for a while. Then the color evolves leftward (blueward in B – V but almost constant in U – B), owing mainly to the development of strong emission lines. This is the general course of nova outbursts in the color-color diagram, which was deduced from eight well-observed novae in various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining the color excesses of classical novae. Using this method, we redetermined the color excesses of 20 well-observed novae. The obtained color excesses are in reasonable agreement with the previous results, which in turn support the idea of our general track of nova outbursts. Additionally, we estimated the absolute V magnitudes of about 30 novae using a method for time-stretching nova light curves to analyze the distance-reddening relations of the novae.

  16. A polarization study of dwarf novae and nova-like objects

    NASA Astrophysics Data System (ADS)

    Szkody, P.; Michalsky, J. J.; Stokes, G. M.

    1982-02-01

    Linear polarization measurements for four dwarf novae (SS Cyg, RX And, U Gem, and AH Her) and six nova-like variables (AE Aqr, V426 Oph, UX UMa, CI Cyg, EZ Peg, and TT Ari) are obtained to study variability associated with the outburst cycle. No polarization changes are apparent for SS Cyg or RX And throughout their outburst cycles, but an appreciable difference is noted for AE Aqr. RX And reveals evidence for variability on orbital time scales. All four systems studied at various wavelengths show an unusual wavelength dependence of the polarization.

  17. Constraints on the progenitor system of the type Ia supernova 2014J from pre-explosion Hubble space telescope imaging

    SciTech Connect

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E.; Cenko, S. Bradley; Schaefer, Gail

    2014-07-20

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ≈ 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T ≲ 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of R{sub V} and A{sub V} values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T < 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  18. Constraints on the Progenitor System of the Type Ia Supernova 2014J from Pre-Explosion Hubble Space Telescope Imaging

    NASA Technical Reports Server (NTRS)

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Cenko, S. Bradley; Prato, Lisa; Schaefer, Gail; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E.

    2014-01-01

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d (is) approx. 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T (is) approximately 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of RV and AV values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T (is) less than 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  19. Recent progress in understanding the eruptions of classical novae

    NASA Technical Reports Server (NTRS)

    Shara, Michael M.

    1988-01-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  20. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1988-10-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  1. Nova V745 Sco shows fastest rise of super-soft X-ray emission: 3-4 days after eruption

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Swift started monitoring the recurrent nova V745 Sco on 2014-02-06, 0.16 days after the discovery of the most recent eruption (R. Stubbings, AAVSO Special Notice 380, CBET 3803). Mukai et al. reported the initial Swift observations in ATel #5862, finding that the X-ray emission was hard and highly absorbed, with the absorbing column decreasing with time, resulting in a corresponding increase in count rate.

  2. Spectroscopy and photometry of X Ser (Nova Ser 1903) during its current DN stunted outburst

    NASA Astrophysics Data System (ADS)

    Munari, U.; Dallaporta, S.

    2016-09-01

    The old nova X Ser (Nova Ser 1903) is known to display stunted dwarf-nova outbursts (Honeycutt et al. 1998, AJ 115, 2527), for which multiband photometry - and spectroscopy in particular - seem acutely rare.

  3. Prorenin receptor is critical for nephron progenitors.

    PubMed

    Song, Renfang; Preston, Graeme; Kidd, Laura; Bushnell, Daniel; Sims-Lucas, Sunder; Bates, Carlton M; Yosypiv, Ihor V

    2016-01-15

    Deficient nephrogenesis is the major factor contributing to renal hypoplasia defined as abnormally small kidneys. Nephron induction during kidney development is driven by reciprocal interactions between progenitor cells of the cap mesenchyme (CM) and the ureteric bud (UB). The prorenin receptor (PRR) is a receptor for renin and prorenin, and an accessory subunit of the vacuolar proton pump H(+)-ATPase. Global loss of PRR is lethal in mice and PRR mutations are associated with a high blood pressure, left ventricular hypertrophy and X-linked mental retardation in humans. To circumvent lethality of the ubiquitous PRR mutation in mice and to determine the potential role of the PRR in nephrogenesis, we generated a mouse model with a conditional deletion of the PRR in Six2(+) nephron progenitors and their epithelial derivatives (Six2(PRR-/-)). Targeted ablation of PRR in Six2(+) nephron progenitors caused a marked decrease in the number of developing nephrons, small cystic kidneys and podocyte foot process effacement at birth, and early postnatal death. Reduced congenital nephron endowment resulted from premature depletion of nephron progenitor cell population due to impaired progenitor cell proliferation and loss of normal molecular inductive response to canonical Wnt/β-catenin signaling within the metanephric mesenchyme. At 2 months of age, heterozygous Six2(PRR+/-) mice exhibited focal glomerulosclerosis, decreased kidney function and massive proteinuria. Collectively, these findings demonstrate a cell-autonomous requirement for the PRR within nephron progenitors for progenitor maintenance, progression of nephrogenesis, normal kidney development and function.

  4. Recurrent Fever in Children

    PubMed Central

    Torreggiani, Sofia; Filocamo, Giovanni; Esposito, Susanna

    2016-01-01

    Children presenting with recurrent fever may represent a diagnostic challenge. After excluding the most common etiologies, which include the consecutive occurrence of independent uncomplicated infections, a wide range of possible causes are considered. This article summarizes infectious and noninfectious causes of recurrent fever in pediatric patients. We highlight that, when investigating recurrent fever, it is important to consider age at onset, family history, duration of febrile episodes, length of interval between episodes, associated symptoms and response to treatment. Additionally, information regarding travel history and exposure to animals is helpful, especially with regard to infections. With the exclusion of repeated independent uncomplicated infections, many infective causes of recurrent fever are relatively rare in Western countries; therefore, clinicians should be attuned to suggestive case history data. It is important to rule out the possibility of an infectious process or a malignancy, in particular, if steroid therapy is being considered. After excluding an infectious or neoplastic etiology, immune-mediated and autoinflammatory diseases should be taken into consideration. Together with case history data, a careful physical exam during and between febrile episodes may give useful clues and guide laboratory investigations. However, despite a thorough evaluation, a recurrent fever may remain unexplained. A watchful follow-up is thus mandatory because new signs and symptoms may appear over time. PMID:27023528

  5. Expanded Very Large Array Nova Project Observations of the Classical NovaV1723 Aquilae

    NASA Technical Reports Server (NTRS)

    Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; OBrien, T. J.

    2011-01-01

    We present radio light curves and spectra of the classical nova VI723 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 VI723 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 VI723 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.

  6. Discovery of a Probable Nova in M81 and Photometry of Three M81 Novae

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Errmann, R.; Carlisle, Ch.; Vaduvescu, O.

    2015-02-01

    We report the discovery of a probable nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.6" seeing on 2015 Jan.

  7. Progenitor's Signatures in Type Ia Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Chiotellis, A.; Kosenko, D.; Schure, K. M.; Vink, J.

    2013-01-01

    The remnants of Type Ia supernovae (SNe Ia) can provide important clues about their progenitor histories. We discuss two well-observed supernova remnants (SNRs) that are believed to have resulted from SNe Ia, and use various tools to shed light on the possible progenitor histories. We find that Kepler's SNR is consistent with a symbiotic binary progenitor consisting of a white dwarf and an AGB star. Our hydrosimulations can reproduce the observed kinematic and morphological properties. For Tycho's remnant we use the characteristics of the X-ray spectrum and kinematics to show that the ejecta has likely interacted with dense circumstellar gas.

  8. Progenitor genealogy in the developing cerebral cortex.

    PubMed

    Laguesse, Sophie; Peyre, Elise; Nguyen, Laurent

    2015-01-01

    The mammalian cerebral cortex is characterized by a complex histological organization that reflects the spatio-temporal stratifications of related stem and neural progenitor cells, which are responsible for the generation of distinct glial and neuronal subtypes during development. Some work has been done to shed light on the existing filiations between these progenitors as well as their respective contribution to cortical neurogenesis. The aim of the present review is to summarize the current views of progenitor hierarchy and relationship in the developing cortex and to further discuss future research directions that would help us to understand the molecular and cellular regulating mechanisms involved in cerebral corticogenesis. PMID:25141969

  9. V4743 Sgr, a magnetic nova?

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    Two XMM-Newton observations of Nova V4743 Sgr (Nova Sgr 2002) were performed shortly after it returned to quiescence, 2 and 3.5 yr 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 Southern African Large Telescope (SALT) 11.5 yr 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 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.

  10. [Treatment of recurrent furunculosis].

    PubMed

    Engelhard, Esther A N; Spanjaard, Lodewijk; Stijnis, C Kees

    2013-01-01

    The management of recurrent furunculosis is difficult, and often disappointing. We present the case of a 23-year-old female patient suffering from recurrent furunculosis. The furunculosis persisted after treatment with mupirocin nasal ointment, chlorhexidine soap and instructions for washing clothes, towels and bed sheets for a period of 7 days. Treatment with low-dose clindamycin for three months ultimately proved successful. We propose a structural approach for recurrent furunculosis in which extensive history-taking is followed by appropriate tests. Before prescribing an oral antibiotic (preferably low-dose clindamycin or a macrolide for 3 months), the patient should use an antimicrobial nasal ointment and soap and follow hygienic instructions as mentioned above. Members of the household who also have signs of the infection should be treated. Hygienic education is an essential component of treatment. We believe that this approach will lead to a treatment that is more effective and efficient.

  11. Recurrent wheezing in children

    PubMed Central

    Piazza, Michele; Piacentini, Giorgio

    2016-01-01

    Recurrent wheezing have a significant morbidity and it’s estimated that about one third of school-age children manifest the symptom during the first 5 years of life. Proper identification of children at risk of developing asthma at school age may predict long-term outcomes and improve treatment and preventive approach, but the possibility to identify these children at preschool age remains limited. For many years authors focused their studies to identify early children with recurrent wheezing at risk to develop asthma at school age. Different phenotypes have been proposed for a more precise characterization and a personalized plan of treatment. The main criticism concerns the inability to define stable phenotypes with the risk of overestimating or underestimating the characteristics of symptoms in these children. The aim of this review is to report the recent developments on the diagnosis and treatment of recurrent paediatric wheezing. PMID:26835404

  12. [Treatment of recurrent furunculosis].

    PubMed

    Engelhard, Esther A N; Spanjaard, Lodewijk; Stijnis, C Kees

    2013-01-01

    The management of recurrent furunculosis is difficult, and often disappointing. We present the case of a 23-year-old female patient suffering from recurrent furunculosis. The furunculosis persisted after treatment with mupirocin nasal ointment, chlorhexidine soap and instructions for washing clothes, towels and bed sheets for a period of 7 days. Treatment with low-dose clindamycin for three months ultimately proved successful. We propose a structural approach for recurrent furunculosis in which extensive history-taking is followed by appropriate tests. Before prescribing an oral antibiotic (preferably low-dose clindamycin or a macrolide for 3 months), the patient should use an antimicrobial nasal ointment and soap and follow hygienic instructions as mentioned above. Members of the household who also have signs of the infection should be treated. Hygienic education is an essential component of treatment. We believe that this approach will lead to a treatment that is more effective and efficient. PMID:23369819

  13. Discovery of Two Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Zurita, C.; Patrick, L.; Ledo, H.; Karjalainen, R.

    2012-05-01

    We report the discovery of two novae in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~0.8" seeing on May 22.901 UT. The new objects are well visible on the co-added image (see the finding chart linked below) as well as on individual 400-s frames, but are not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.3.

  14. Supernova hydrodynamics experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A.; Kane, J.; Arnett, D.; Drake, R.P.; McCray, R.

    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.

  15. Review of the classical nova outburst

    SciTech Connect

    Starrfield, S.; Sparks, W.M.

    1986-06-01

    Observational studies have not only identified a new class of novae but theoretical simulations of this class have been found to be in excellent agreement with the observations. This new class consists of outbursts occurring on ONeMg white dwarfs in close binar systems in contrast to the other outbursts which are occurring on CO white dwarfs. We also review the effects of the ..beta../sup +/-unstable nuclei and show how their presence has a major effect on the evolution. 77 refs.

  16. New disk nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Pietsch, W.; Burwitz, V.; Rodriguez, J.; Bochinski, J.; Busuttil, R.; Haswell, C. A.; Holmes, S.; Kolb, U.

    2012-02-01

    We report the discovery of a possible nova in the south-western disk of M 31 on a 5x120s dithered stacked CCD image obtained with the Open University PIRATE Planewave CDK17 0.43m Dall-Kirkham f/6.7 telescope at the Observatorio Astronomico de Mallorca (Costitx, Spain), using an SBIG STX 16803 CCD Camera (with a Kodak 4k x 4k chip with 9 microns sq. pixels) and Baader clear filter, on 2012 Feb 15.803 UT with a R magnitude of 17.5 (accuracy of 0.2 mag).

  17. New nova candidate in M81

    NASA Astrophysics Data System (ADS)

    Henze, M.; Sala, G.; Jose, J.; Figueira, J.; Hernanz, M.

    2016-06-01

    We report the discovery of a new nova candidate in the M81 galaxy on 16x200s stacked R filter CCD images, obtained with the 80 cm Ritchey-Chretien F/9.6 Joan Oro telescope at Observatori Astronomic del Montsec, owned by the Catalan Government and operated by the Institut d'Estudis Espacials de Catalunya, Spain, using a Finger Lakes PL4240-1-BI CCD Camera (with a Class 1 Basic Broadband coated 2k x 2k chip with 13.5 microns sq. pixels).

  18. Recurrent pregnancy loss.

    PubMed

    Hatasaka, H H; Varner, M W

    1994-12-01

    Recurrent pregnancy loss is a frustrating clinical dilemma for both patients and physicians because, in most cases, causes are nebulous and few treatments with proven benefit can be offered. Involved, expensive tests have frequently been proposed and their use has often filtered into clinical practice before their utility has been firmly demonstrated. Proposed causes of recurrent pregnancy loss include genetic and environmental etiologies, infectious agents, maternal congenital and acquired anatomic abnormalities, and immunologic and endocrinologic dysfunction. Appropriate management relies upon a realistic understanding of the often substantial limitations of currently available therapies.

  19. Tackling a Recurrent Pinealoblastoma

    PubMed Central

    Palled, Siddanna; Kalavagunta, Sruthi; Beerappa Gowda, Jaipal; Umesh, Kavita; Aal, Mahalaxmi; Abdul Razack, Tanvir pasha Chitraduraga; Gowda, Veerabhadre; Viswanath, Lokesh

    2014-01-01

    Pineoblastomas are rare, malignant, pineal region lesions that account for <0.1% of all intracranial tumors and can metastasize along the neuroaxis. Pineoblastomas are more common in children than in adults and adults account for <10% of patients. The management of pinealoblastoma is multimodality approach, surgery followed with radiation and chemotherapy. In view of aggressive nature few centres use high dose chemotherapy with autologus stem cell transplant in newly diagnosed cases but in recurrent setting the literature is very sparse. The present case represents the management of pinealoblastoma in the recurrent setting with reirradiation and adjuvant carmustine chemotherapy wherein the management guidelines are not definitive. PMID:25210636

  20. Recurrent Aphthous Stomatitis

    PubMed Central

    Akintoye, Sunday O.; Greenberg, Martin S.

    2014-01-01

    Recurrent Aphthous Stomatitis (RAS) is the most common ulcerative disease affecting the oral mucosa. It occurs mostly in healthy individuals and has atypical clinical presentation in immunocompromised individuals. The etiology of RAS is still unknown, but several local, systemic, immunologic, genetic, allergic, nutritional, and microbial factors, as well as immunosuppressive drugs, have been proposed as causative agents. Clinical management of RAS is based on severity of symptoms, frequency, size and number of lesions using topical and systemic therapies. The goals of therapy are to decrease pain and ulcer size, promote healing and decrease frequency of recurrence. PMID:24655523

  1. UBVRI Polarimetry of Nova Sgr 2015#2

    NASA Astrophysics Data System (ADS)

    Muneer, S.; Anupama, G. C.; Raveendran, A. V.; Muniyandi, A.; Baskar, R.

    2015-03-01

    We report here the first polarimetric observations of Nova Sgr 2015#2 (PNV J18365700-2855420). The linear polarization observations of the nova in UBVRI spectral bands were obtained during 16-22 March 2015 with a two beam, multichannel polarimeter attached to the 1-m Carl-Zeiss telescope at the Vainu Bappu Observatory, Kavalur, India.

  2. Results of Statewide TerraNova Testing, Fall 1998.

    ERIC Educational Resources Information Center

    La Marca, Paul M.

    This summary provides key findings about state, district, and school level performance on the TerraNova examinations (CTB/McGraw Hill) in Nevada in 1998-1999. The TerraNova tests are used to assess students in grades 4, 8, and 10 as stipulated by Nevada law. Within this summary, a description of performance as measured by national percentile…

  3. Energy source and pre-explosion progenitor evolution of Super-Luminous SNe

    NASA Astrophysics Data System (ADS)

    Margutti, Raffaella

    2013-10-01

    With bolometric peak luminosities L >7x10^43 erg/sec, the new class of Super Luminous Super Novae (SLSNe) outshine ordinary SNe of more than a factor 10 and represent the death of the most massive stars in our Universe. Their exceptional luminosity requires exotic explosion mechanisms and/or sources of energy whose nature is unclear. Here we propose a focused XMM program to map their X-ray emission down to unprecedented limits as part of our multi-wavelength effort through our programs on the EVLA (radio), Swift (UV) and optical/NIR facilities. The final aim is to: (i) Pin down the energy source of SLSNe; (ii) Map the diversity of the pre-explosion evolution of their progenitors.

  4. Double-Shell Capsule Implosions at NOVA and OMEGA

    NASA Astrophysics Data System (ADS)

    Watt, R. G.; Barnes, Cris W.; Chrien, Robert E.; Delamater, Norman D.; Duke, Joseph R.; Elliott, Norman E.; Gobby, Peter L.; Gomez, Veronica M.; Moore, Joyce E.; Pollak, Gregory D.; Varnum, William S.; Colvin, Jeffrey D.; Lerche, Richard A.; Phillips, Thomas W.

    1998-11-01

    Recent calculations indicate that double shell targets may provide an alternative, non-cryogenic path to ignition on NIF. Experiments have been conducted at the NOVA and OMEGA lasers to study indirectly driven double shell implosions. Double shell implosions in cylindrical hohlraums on NOVA show yields in the range of 1-2% of clean 1D calculations. NOVA implosions may be dominated by the inherent m = 5 beam pattern on either end of the cylindrical hohraum, and have significant time dependent drive asymmetry. Implosions at the OMEGA facility were done in the tethrahedral holhraum geometry which provides improved time dependent symmetry. Primary diagnostics in these implosions are the neutron diagnostics available at both facilities. NOVA shots used DD, while the OMEGA shots used both DD and DT to maximize the available information from the implosions. Individual implosion data and comparison to simulations will be shown for NOVA and OMEGA double shell implosions.

  5. New Features of the Symbiotic Recurrent Nova V407 Cygni Found in the Outburst in 2010

    NASA Astrophysics Data System (ADS)

    Iijima, T.

    2015-07-01

    The spectral evolution of V407 Cyg during the outburst in 2010 is reported. The coronal emission lines [Fe x] 6374, [Ar x] 5535, and [Ar xi] 6919 strengthened rapidly around day 20 of the outburst, which coincided with the growth of soft X-ray flux. On the other hand, the non-coronal forbidden lines [O i], [N ii], [O iii], etc. strengthened between days 40 and 60, which coincided with the fading of the soft X-rays. The luminosities in the UV and optical regions also decreased in the same period, and were seen as bends on the light curves. Our observations suggest that the fading of the soft X-rays and the bends on the light curves were likely related to a rapid decreasing of the emission measure of the nebulosity, and may not have been due to the cessation of the hydrogen burning in the system. It seems that the coronal emission lines were emitted by the collision of the ejecta with the circumstellar envelope as well as the soft X-rays. Intensities of the emission lines of He i relative to Hβ probably increased in the first 3 days of the outburst and decreased in the successive 10 days and then recovered, while no other line showed a similar variation. The variations in intensity of the He i emission lines coincided with that of the γ-ray flux in the first two weeks of the outburst. The helium abundance derived from the intensities of the He i and He ii emission lines relative to Hβ appeared to have decreased from N(He) = 0.17 to 0.076 according to the fading of the He i lines, and then increased to 0.20 when the intensities recovered in the later stage of the outburst. It is unlikely that the helium abundance really changed so much during the outburst. There might have been an unknown mechanism that weakened the He i emission lines. The distance to V407 Cyg is estimated to be 5.3+/- 1 kpc. The absolute V mag at maximum light of the outburst was probably fainter by about 0.6 mag than that expected from the time for a 2 mag decline.

  6. Quark nova model for fast radio bursts

    NASA Astrophysics Data System (ADS)

    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.

  7. Quark nova model for fast radio bursts

    NASA Astrophysics Data System (ADS)

    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.

  8. SALT observations of southern post-novae

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Swierczynski, E.; Mikolajewski, M.; Ilkiewicz, K.

    2015-04-01

    Aims: We report on recent optical observations of the stellar and the nebular remnants of 22 southern post-novae. Methods: In this study, for each of our targets, we obtained and analysed long-slit spectra in the spectral range 3500-6600 Å and in Hα+[N ii] narrow-band images. Results: The changes in the emission lines' equivalent widths with the time since the outburst agree with earlier published results of other authors. We estimated an average value α = 2.37 for the exponent of the power law fitted to the post-novae continua. Our observations clearly show the two-component structure of the V842 Cen expanding nebulae, owing to the different velocities of the ejected matter. We discovered an expanding shell around V382 Vel with an outer diameter of about 12″. Based on observations made with the Southern African Large Telescope (SALT).The spectra as FITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/576/A119

  9. Developing beam phasing on the Nova laser

    SciTech Connect

    Ehrlich, R.B.; Amendt, P.A.; Dixit, S.N.; Hammel, B.A.; Kalantar, D.H.; Pennington, D.M.; Weiland, T.L.

    1997-03-10

    We are presently adding the capability to irradiate indirectly-driven Nova targets with two rings of illumination inside each end of the hohlraum for studies of time-dependent second Legendre (P2) and time- integrated fourth Legendre (P4) flux asymmetry control. The rings will be formed with specially designed kinoform phase plates (KPPs), which will direct each half of each beam into two separate rings that are nearly uniform azimuthally. The timing and temporal pulse shape of the outer rings will be controlled independently from those of the inner rings, allowing for phasing of the pulse shapes to control time dependent asymmetry. Modifications to the incident beam diagnostics (IBDS) will enable us to verify that acceptable levels of power balance among the contributing segments of each ring have been achieved on each shot. Current techniques for precision beam pointing and timing are expected to be sufficiently accurate for these experiments. We present a design for an affordable retrofit to achieve beam phasing on Nova, results of a simplified demonstration, and calculations highlighting the anticipated benefits.

  10. Spitzer IRS Observations of ``Mature'' Novae

    NASA Astrophysics Data System (ADS)

    Helton, L. Andrew; Woodward, C. E.; Evans, A.; Gehrz, R. D.; Lynch, D. L.; Rudy, R.; Schwarz, G. J.; Vanlandingham, K.; Spitzer Nova Team

    2009-01-01

    Many facets of astrophysics are captured in classical nova (CN) eruptions, making them unique laboratories in which we may observe several poorly understood astrophysical processes including mass transfer, thermonuclear runaway, optically thick winds, common envelope evolution, molecule and grain formation, coronal line emission, and gas cooling by fine structure lines. Many of these phenomena evolve in real time. Therefore, a better understanding of CNe has far-reaching applications and underpins several related and important areas of astrophysics. Here we present preliminary results of our Cycle 5 Spitzer IRS study of ``mature'' novae (several 100s of days post-outburst), complemented by extensive multi-wavelength data from other facilities. We present data on V2361 Cyg, V2467 Cyg and V378 Ser. In particular, V2361 Cyg displays a strong dust continuum with possible Aromatic Emission Features (AEF) superimposed, the first dusty CN observed to do so since 1993 and the first to be observed spectroscopically in the far IR. This object presents us with an outstanding opportunity to investigate how the dust is processed by the UV radiation from the stellar remnant. Support for this work was provided in part by NASA through Spitzer contracts issued by JPL/Caltech to the University of Minnesota.

  11. V390 Nor = Nova Normae 2007

    NASA Astrophysics Data System (ADS)

    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.

  12. Progenitor cells in pulmonary vascular remodeling.

    PubMed

    Yeager, Michael E; Frid, Maria G; Stenmark, Kurt R

    2011-01-01

    Pulmonary hypertension is characterized by cellular and structural changes in the walls of pulmonary arteries. Intimal thickening and fibrosis, medial hypertrophy and fibroproliferative changes in the adventitia are commonly observed, as is the extension of smooth muscle into the previously non-muscularized vessels. A majority of these changes are associated with the enhanced presence of α-SM-actin+ cells and inflammatory cells. Atypical abundances of functionally distinct endothelial cells, particularly in the intima (plexiform lesions), and also in the perivascular regions, are also described. At present, neither the origin(s) of these cells nor the molecular mechanisms responsible for their accumulation, in any of the three compartments of the vessel wall, have been fully elucidated. The possibility that they arise from either resident vascular progenitors or bone marrow-derived progenitor cells is now well established. Resident vascular progenitor cells have been demonstrated to exist within the vessel wall, and in response to certain stimuli, to expand and express myofibroblastic, endothelial or even hematopoietic markers. Bone marrow-derived or circulating progenitor cells have also been shown to be recruited to sites of vascular injury and to assume both endothelial and SM-like phenotypes. Here, we review the data supporting the contributory role of vascular progenitors (including endothelial progenitor cells, smooth muscle progenitor cells, pericytes, and fibrocytes) in vascular remodeling. A more complete understanding of the processes by which progenitor cells modulate pulmonary vascular remodeling will undoubtedly herald a renaissance of therapies extending beyond the control of vascular tonicity and reduction of pulmonary artery pressure. PMID:22034593

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

    NASA Astrophysics Data System (ADS)

    Soraisam, Monika D.; Gilfanov, Marat; Wolf, William M.; Bildsten, Lars

    2016-01-01

    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 white dwarf (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 Lx ≥ 1036 erg s-1. Their combined unabsorbed luminosity is of the order of ˜1039 erg s-1. Their luminosity distribution shows significant steepening around log (Lx) ˜ 37.7-38 and becomes zero at Lx ≈ 2 × 1038 erg s-1, the maximum Lx 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 Teff ≈ 1.5 × 106 K. We compare our predictions with the results of the XMM-Newton monitoring of the central field of M31 between 2006 and 2009. The predicted number of post-nova SSSs exceeds the observed number by a factor of ≈2-5, depending on the assumed WD mass distribution in novae. This is good agreement, considering the number and magnitude of uncertainties involved in calculations of the post-nova evolutionary models and their X-ray output. Furthermore, only a moderate circumstellar absorption, with hydrogen column density of the order of ˜1021 cm-2, will remove the discrepancy.

  14. Observations and simulations of nova Vul 1984 no. 2: A nova with ejecta rich in oxygen, neon, and magnesium

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Sonneborn, G.; Stryker, L. L.; Sparks, Warren M.; Truran, James W.; Ferland, Gary; Wagner, R. M.; Gallagher, J. S.; Wade, R.; Williams, R. E.

    1988-01-01

    Nova Vul 1984 no. 2 was observed with IUE from Dec. 1984 through Nov. 1987. The spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium.

  15. Recurrent infective endocarditis.

    PubMed Central

    Lossos, I. S.; Oren, R.

    1993-01-01

    Infective endocarditis is a serious disease associated with high mortality. Patients surviving recurrent bouts of infective endocarditis are reported infrequently. We report on a non-drug abuser patient who experienced seven episodes of infective endocarditis--the largest number reported to our knowledge in a single non-drug abuser patient. PMID:8290417

  16. Lung Cancer Indicators Recurrence

    Cancer.gov

    This study describes prognostic factors for lung cancer spread and recurrence, as well as subsequent risk of death from the disease. The investigators observed that regardless of cancer stage, grade, or type of lung cancer, patients in the study were more

  17. On Solving Linear Recurrences

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2013-01-01

    A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.

  18. Recurrent Corneal Erosion

    MedlinePlus

    ... to apply a tight patch that restricts eye movement at night and upon waking so there is less likelihood of recurrence. If these rather simple procedures are not successful, the eye care professional may re-scrape the area to create a more irregular abrasion followed by ...

  19. Swift detection of the super-swift switch-on of the super-soft phase in nova V745 Sco (2014)

    NASA Astrophysics Data System (ADS)

    Page, K. L.; Osborne, J. P.; Kuin, N. P. M.; Henze, M.; Walter, F. M.; Beardmore, A. P.; Bode, M. F.; Darnley, M. J.; Delgado, L.; Drake, J. J.; Hernanz, M.; Mukai, K.; Nelson, T.; Ness, J.-U.; Schwarz, G. J.; Shore, S. N.; Starrfield, S.; Woodward, C. E.

    2015-12-01

    V745 Sco is a recurrent nova, with the most recent eruption occurring in February 2014. V745 Sco was first observed by Swift a mere 3.7 h after the announcement of the optical discovery, with the super-soft X-ray emission being detected around 4 d later and lasting for only ˜2 d, making it both the fastest follow-up of a nova by Swift and the earliest switch-on of super-soft emission yet detected. Such an early switch-on time suggests a combination of a very high velocity outflow and low ejected mass and, together with the high effective temperature reached by the super-soft emission, a high mass white dwarf (>1.3 M⊙). The X-ray spectral evolution was followed from an early epoch where shocked emission was evident, through the entirety of the super-soft phase, showing evolving column density, emission lines, absorption edges, and thermal continuum temperature. UV grism data were also obtained throughout the super-soft interval, with the spectra showing mainly emission lines from lower ionization transitions and the Balmer continuum in emission. V745 Sco is compared with both V2491 Cyg (another nova with a very short super-soft phase) and M31N 2008-12a (the most rapidly recurring nova yet discovered). The longer recurrence time compared to M31N 2008-12a could be due to a lower mass accretion rate, although inclination of the system may also play a part. Nova V745 Sco (2014) revealed the fastest evolving super-soft source phase yet discovered, providing a detailed and informative data set for study.

  20. Recurrent Infections May Signal Immunodeficiencies

    MedlinePlus

    ... Search AAAAI Breadcrumb navigation Home ▸ Conditions & Treatments ▸ Library ▸ Primary Immunodeficiency Disease Library ▸ Recurrent Infections May Signal Immunodeficiencies Share | Recurrent Infections May Signal Immunodeficiencies This article has been reviewed by Thanai Pongdee, MD, FAAAAI ...

  1. Innovative approaches to recurrent training

    NASA Technical Reports Server (NTRS)

    Noon, H.; Murphy, M.

    1984-01-01

    Innovative approaches to recurrent training for regional airline aircrews are explored. Guidelines for recurrent training programs which include in corporation of cockpit resource management are discussed. B.W.

  2. Light-curve Analysis of Neon Novae

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2016-01-01

    We analyzed light curves of five neon novae, QU Vul, V351 Pup, V382 Vel, V693 CrA, and V1974 Cyg, and determined their white dwarf (WD) masses and distance moduli on the basis of theoretical light curves composed of free-free and photospheric emission. For QU Vul, we obtained a distance of d ˜ 2.4 kpc, reddening of E(B - V) ˜ 0.55, and WD mass of MWD = 0.82-0.96 {M}⊙ . This suggests that an oxygen-neon WD lost a mass of more than ˜ 0.1 {M}⊙ since its birth. For V351 Pup, we obtained d˜ 5.5 {{kpc}}, E(B-V)˜ 0.45, and {M}{{WD}}=0.98-1.1 {M}⊙ . For V382 Vel, we obtained d˜ 1.6 {{kpc}}, E(B-V)˜ 0.15, and {M}{{WD}}=1.13-1.28 {M}⊙ . For V693 CrA, we obtained d˜ 7.1 {{kpc}}, E(B-V)˜ 0.05, and {M}{{WD}}=1.15-1.25 {M}⊙ . For V1974 Cyg, we obtained d˜ 1.8 {{kpc}}, E(B-V)˜ 0.30, and {M}{{WD}}=0.95-1.1 {M}⊙ . For comparison, we added the carbon-oxygen nova V1668 Cyg to our analysis and obtained d˜ 5.4 {{kpc}}, E(B-V)˜ 0.30, and {M}{{WD}}=0.98-1.1 {M}⊙ . In QU Vul, photospheric emission contributes 0.4-0.8 mag at most to the optical light curve compared with free-free emission only. In V351 Pup and V1974 Cyg, photospheric emission contributes very little (0.2-0.4 mag at most) to the optical light curve. In V382 Vel and V693 CrA, free-free emission dominates the continuum spectra, and photospheric emission does not contribute to the optical magnitudes. We also discuss the maximum magnitude versus rate of decline relation for these novae based on the universal decline law.

  3. CLIP Identifies Nova-Regulated RNA Networks in the Brain

    NASA Astrophysics Data System (ADS)

    Ule, Jernej; Jensen, Kirk B.; Ruggiu, Matteo; Mele, Aldo; Ule, Aljaž; Darnell, Robert B.

    2003-11-01

    Nova proteins are neuron-specific antigens targeted in paraneoplastic opsoclonus myoclonus ataxia (POMA), an autoimmune neurologic disease characterized by abnormal motor inhibition. Nova proteins regulate neuronal pre-messenger RNA splicing by directly binding to RNA. To identify Nova RNA targets, we developed a method to purify protein-RNA complexes from mouse brain with the use of ultraviolet cross-linking and immunoprecipitation (CLIP). Thirty-four transcripts were identified multiple times by Nova CLIP. Three-quarters of these encode proteins that function at the neuronal synapse, and one-third are involved in neuronal inhibition. Splicing targets confirmed in Nova-/- mice include c-Jun N-terminal kinase 2, neogenin, and gephyrin; the latter encodes a protein that clusters inhibitory γ-aminobutyric acid and glycine receptors, two previously identified Nova splicing targets. Thus, CLIP reveals that Nova coordinately regulates a biologically coherent set of RNAs encoding multiple components of the inhibitory synapse, an observation that may relate to the cause of abnormal motor inhibition in POMA.

  4. Non-detection of nova shells around asynchronous polars

    NASA Astrophysics Data System (ADS)

    Pagnotta, Ashley; Zurek, David

    2016-05-01

    Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e. their WD and orbital angular velocities are the same). Past nova eruptions are the predicted cause of the asynchronicity, in part due to the fact that one of the APs, V1500 Cyg, was observed to undergo a nova eruption in 1975. We used the Southern African Large Telescope 10 m class telescope and the MDM 2.4 m Hiltner telescope to search for nova shells around three of the remaining four APs (V1432 Aql, BY Cam, and CD Ind) as well as one Intermediate Polar with a high asynchronicity (EX Hya). We found no evidence of nova shells in any of our images. We therefore cannot say that any of the systems besides V1500 Cyg had nova eruptions, but because not all post-nova systems have detectable shells, we also cannot exclude the possibility of a nova eruption occurring in any of these systems and knocking the rotation out of sync.

  5. Non-Detection of Nova Shells Around Asynchronous Polars

    NASA Astrophysics Data System (ADS)

    Pagnotta, Ashley; Zurek, David

    2016-01-01

    Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e., their WD and orbital angular velocities are the same). Past nova eruptions are the predicted cause of the asynchronicity, in part due to the fact that one of the APs, V1500 Cyg, was observed to undergo a nova eruption in 1975. We used the SALT 10m-class telescope and the MDM 2.4m Hiltner telescope to search for nova shells around three of the remaining four APs (V1432 Aql, BY Cam, and CD Ind) as well as one Intermediate Polar with a high asynchronicity (EX Hya). We found no evidence of nova shells in any of our images. We therefore cannot say that any of the systems besides V1500 Cyg had nova eruptions, but because not all post-nova systems have detectable shells, we also cannot exclude the possibility of a nova eruption occurring in any of these systems and knocking the rotation out of sync.

  6. Nova Delphini 2013 = PNV J20233073+2046041

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-08-01

    Announces the discovery of Nova Delphini 2013 = PNV J20233073+2046041 = V339 Del by Koichi Itagaki (Teppo-cho, Yamagata, Japan) on 2013 Aug. 14.584 UT at unfiltered CCD magnitude mag 6.8. Spectra by numerous professional and amateur astronomers show strong H-alpha and H-beta emission and P Cygni profile emission lines, all pointing to a pre-maximum classical nova. For details on spectra, see CBET 3628 and the IAU Circular to be announced shortly. Postings to the AAVSO Spectroscopy Forum (http://www.aavso.org/forums/variable-star-observing/spectroscopy) also contain information on spectra, as well as observing and reporting instructions for spectroscopists. Charts for Nova Del 2013 may be created using the AAVSO Variable Star Plotter (VSP) at http://www.aavso.org/vsp. We have created a binocular sequence for this nova that can be plotted using the Binocular Chart option on VSP. Over 750 observations have been submitted to the AAVSO International Database since the nova's discovery two days ago; the most recent observations show Nova Del 2013 has brightened to visual magnitude 4.4. Observations should be submitted to the AAVSO International Database. Announced on IAU CBAT CBET 3628 (Daniel W. E. Green, ed.). Nova Del 2013 was designated PNV J20233073+2046041 when it was posted on the CBAT TOCP webpage. See full Alert Notice for more details, observations, and links to images.

  7. Laying the foundation for a digital Nova Scotia

    NASA Astrophysics Data System (ADS)

    Bond, J.

    2016-04-01

    In 2013, the Province of Nova Scotia began an effort to modernize its coordinate referencing infrastructure known as the Nova Scotia Coordinate Referencing System (NSCRS). At that time, 8, active GPS stations were installed in southwest Nova Scotia to evaluate the technology's ability to address the Province's coordinate referencing needs. The success of the test phase helped build a business case to implement the technology across the entire Province. It is anticipated that by the end of 2015, 40 active GPS stations will be in place across Nova Scotia. This infrastructure, known as the Nova Scotia Active Control Stations (NSACS) network, will allow for instantaneous, centimetre level positioning across the Province. Originally designed to address the needs of the surveying community, the technology has also proven to have applications in mapping, machine automation, agriculture, navigation, emergency response, earthquake detection and other areas. In the foreseeable future, all spatial data sets captured in Nova Scotia will be either directly or indirectly derived from the NSACS network. The technology will promote high accuracy and homogenous spatial data sets across the Province. The technology behind the NSACS and the development of the system are described. Examples of how the technology is contributing to a digital Nova Scotia are presented. Future applications of the technology are also considered.

  8. Nova is an old hand at big deals in Alberta

    SciTech Connect

    Sutherland, J.

    1980-09-10

    Nova, an Alberta Corporation, formerly Alberta Gas Trunk Line Co. Ltd., and Shell Canada Resources Ltd. will build a 600 million lb/yr styrene plant near Edmonton, Alberta. For feedstock, 5000 bbl/day of benzene will come from a $350 million, 100,000 bbl/day refinery that will be built by Shell at Edmonton. Husky Oil Ltd., which is controlled by Nova, will take a 40% equity in the refinery. According to Nova, which has a monopoly on gas transmission in Alberta, continued collaboration with Shell could lead to the spending of an additional $2 billion in the next few years. Dow Chemical of Canada Ltd. and Nova will put together an ethane extraction system in Alberta which will feed their jointly owned 1.2 billion lb/yr ethylene plant near Red Deer, Alberta. Dow uses the entire output of the ethylene plant at its recently completed Fort Saskatchewan, Alberta, complex. Alberta Gas Ethylene Co. Ltd., a Nova subsidiary, has begun work on a second 1.2 billion lb/yr ethylene unit scheduled for completion in early 1984, and will soon start work on a third ethylene unit at Red Deer. According to J. Sutherland (Nova, Alberta Corp.), Nova is rapidly expanding its ethylene capacity because, for at least a certain period of time, world-scale plants using Alberta natural gas will be very competitive.

  9. An X-ray source associated with a Vista Variables Survey nova candidate nova

    NASA Astrophysics Data System (ADS)

    Orio, M.; Mukai, K.; Valle, M. Della

    2016-02-01

    We report that one of the ten Galactic transients proposed to be novae, discovered in the Vista-Variables-Via Lactea (VVV) Survey disk area by Saito et al. (ATel 8602), VVV-NOV-13, is spatially coincident with a faint, hard X-ray source observed in 2011 June 16 and 17 for 19700 s in a survey of the NORMA spiral arm with the Chandra ACIS-I camera (P.I.

  10. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  11. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  12. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  13. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  14. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  15. Recurrent Education: Trends and Issues.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France). Centre for Educational Research and Innovation.

    The document, consisting of three parts, focuses on recurrent education and the need for more effective deployment of educational resources within member countries of the Organization for Economic Cooperation and Development. The first section discusses the rationale for recurrent education. Recurrent education presents an educational opportunity…

  16. Origins of Absorption Systems of Classical Nova V2659 Cyg (Nova Cyg 2014)

    NASA Astrophysics Data System (ADS)

    Arai, A.; Kawakita, H.; Shinnaka, Y.; Tajitsu, A.

    2016-10-01

    We report on high-dispersion spectroscopy results of a classical nova V2659 Cyg (Nova Cyg 2014) that are taken 33.05 days after the V-band maximum. The spectrum shows two distinct blueshifted absorption systems originating from H i, Fe ii, Ca ii, etc. The radial velocities of the absorption systems are ‑620 km s‑1, and ‑1100 to ‑1500 km s‑1. The higher velocity component corresponds to the P-Cygni absorption features frequently observed in low-resolution spectra. Much larger numbers of absorption lines are identified at the lower velocity. These mainly originate from neutral or singly ionized Fe-peak elements (Fe i, Ti ii, Cr ii, etc.). Based on the results of our spectroscopic observations, we discuss the structure of the ejecta of V2659 Cyg. We conclude that the low- and high-velocity components are likely to be produced by the outflow wind and the ballistic nova ejecta, respectively.

  17. Neural Progenitors Adopt Specific Identities by Directly Repressing All Alternative Progenitor Transcriptional Programs.

    PubMed

    Kutejova, Eva; Sasai, Noriaki; Shah, Ankita; Gouti, Mina; Briscoe, James

    2016-03-21

    In the vertebrate neural tube, a morphogen-induced transcriptional network produces multiple molecularly distinct progenitor domains, each generating different neuronal subtypes. Using an in vitro differentiation system, we defined gene expression signatures of distinct progenitor populations and identified direct gene-regulatory inputs corresponding to locations of specific transcription factor binding. Combined with targeted perturbations of the network, this revealed a mechanism in which a progenitor identity is installed by active repression of the entire transcriptional programs of other neural progenitor fates. In the ventral neural tube, sonic hedgehog (Shh) signaling, together with broadly expressed transcriptional activators, concurrently activates the gene expression programs of several domains. The specific outcome is selected by repressive input provided by Shh-induced transcription factors that act as the key nodes in the network, enabling progenitors to adopt a single definitive identity from several initially permitted options. Together, the data suggest design principles relevant to many developing tissues. PMID:26972603

  18. Prevention of recurrent nephrolithiasis.

    PubMed

    Goldfarb, D S; Coe, F L

    1999-11-15

    The first episode of nephrolithiasis provides an opportunity to advise patients about measures for preventing future stones. Low fluid intake and excessive intake of protein, salt and oxalate are important modifiable risk factors for kidney stones. Calcium restriction is not useful and may potentiate osteoporosis. Diseases such as hyperparathyroidism, sarcoidosis and renal tubular acidosis should be considered in patients with nephrolithiasis. A 24-hour urine collection with measurement of the important analytes is usually reserved for use in patients with recurrent stone formation. In these patients, the major urinary risk factors include hypercalciuria, hyperoxaluria, hypocitraturia and hyperuricosuria. Effective preventive and treatment measures include thiazide therapy to lower the urinary calcium level, citrate supplementation to increase the urinary citrate level and, sometimes, allopurinol therapy to lower uric acid excretion. Uric acid stones are most often treated with citrate supplementation. Data now support the cost-effectiveness of evaluation and treatment of patients with recurrent stones. PMID:10593318

  19. Distributed computer control system in the Nova Laser Fusion Test Facility

    SciTech Connect

    Not Available

    1985-09-01

    The EE Technical Review has two purposes - to inform readers of various activities within the Electronics Engineering Department and to promote the exchange of ideas. The articles, by design, are brief summaries of EE work. The articles included in this report are as follows: Overview - Nova Control System; Centralized Computer-Based Controls for the Nova Laser Facility; Nova Pulse-Power Control System; Nova Laser Alignment Control System; Nova Beam Diagnostic System; Nova Target-Diagnostics Control System; and Nova Shot Scheduler. The 7 papers are individually abstracted.

  20. NOVAE EJECTA AS DISCRETE ADIABATICALLY EXPANDING GLOBULES

    SciTech Connect

    Williams, Robert

    2013-09-15

    Available data for novae show that the X-ray and visible spectral regions correlate with each other as they evolve. Large differences in ionization exist simultaneously in the two wavelength regimes, and a straightforward model is proposed that explains the characteristics observed in both spectral regimes. Its key features are (1) ejected blobs of very high density gas from the white dwarf (WD) that expand to create within each clump a wide range of emitting density, ionization, and velocity, and (2) a more homogeneous circumbinary envelope of gas that is produced by secondary star mass loss. The relative mass loss rates from the two stars determine whether the He/N or the Fe II visible spectrum predominates during decline, when hard X-rays are detected, and when the WD can be detected as a super soft X-ray source.

  1. Novae Ejecta as Discrete Adiabatically Expanding Globules

    NASA Astrophysics Data System (ADS)

    Williams, Robert

    2013-09-01

    Available data for novae show that the X-ray and visible spectral regions correlate with each other as they evolve. Large differences in ionization exist simultaneously in the two wavelength regimes, and a straightforward model is proposed that explains the characteristics observed in both spectral regimes. Its key features are (1) ejected blobs of very high density gas from the white dwarf (WD) that expand to create within each clump a wide range of emitting density, ionization, and velocity, and (2) a more homogeneous circumbinary envelope of gas that is produced by secondary star mass loss. The relative mass loss rates from the two stars determine whether the He/N or the Fe II visible spectrum predominates during decline, when hard X-rays are detected, and when the WD can be detected as a super soft X-ray source.

  2. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    SciTech Connect

    Fuller, Jim; Lai Dong

    2012-09-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10{sup 5}-10{sup 6} years.

  3. Classical Rayleigh Taylor experiments on Nova

    SciTech Connect

    Budil, K.S.; Remington, B.A.; Peyser, T.A.

    1995-07-01

    The evolution of the Rayleigh-Taylor (RT) instability in a compressible medium was investigated both at an accelerating embedded interface and at the ablation front in a new series of experiments on Nova. The x-ray drive generated in a hohlraum ablatively accelerated a planar target consisting of a doped plastic pusher which was in some cases backed by a higher density titanium payload. Both target types were diagnosed by face-on and side-on radiography. Experiments have been done with a variety of wavelengths and initial amplitudes. In the case where the perturbed RT-unstable embedded interface is isolated from the ablation front, short wavelength perturbations are observed to grow strongly. When the perturbation is at the ablation front, the short wavelengths are observed to be severely stabilized.

  4. Microstructures of Rare Silicate Stardust from Nova and Supernovae

    NASA Technical Reports Server (NTRS)

    Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S

    2011-01-01

    Most silicate stardust analyzed in the laboratory and observed around stellar environments derives from O-rich red giant and AGB stars [1,2]. Supernova (SN) silicates and oxides are comparatively rare, and fewer than 10 grains from no-va or binary star systems have been identified to date. Very little is known about dust formation in these stellar environments. Mineralogical studies of only three O-rich SN [3-5] and no nova grains have been performed. Here we report the microstructure and chemical makeup of two SN silicates and one nova grain.

  5. The analysis of spectra of novae taken near maximum

    NASA Technical Reports Server (NTRS)

    Stryker, L. L.; Hestand, J.; Starrfield, S.; Wehrse, R.; Hauschildt, P.; Spies, W.; Baschek, B.; Shaviv, G.

    1988-01-01

    A project to analyze ultraviolet spectra of novae obtained at or near maximum optical light is presented. 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. Spectra obtained late in the outburst show only emission lines from highly ionized species and in many cases these are forbidden lines. The ultraviolet data will be used with 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.

  6. Liquid Scintillator Production for the NOvA Experiment

    SciTech Connect

    Mufson, S.; Baugh, B.; Bower, C.; Coan, T.; Cooper, J.; Corwin, L.; Karty, J.; Mason, P.; Messier, M. D.; Pla-Dalmau, A.; Proudfoot, M.

    2015-04-15

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

  7. Eclipse Mapping Experiments in Dwarf Novae Outbursts

    NASA Astrophysics Data System (ADS)

    Borges, B. W.; Baptista, R.

    2006-06-01

    In this work, we report the eclipse mapping analysis of CCD photometric data of two short period dwarf novae - V4140 Sgr (Borges & Baptista 2005) and HT Cas (Borges, Baptista & Catalán, in preparation) - during observed outburst events. The analysis of the observations of V4140 Sgr, done between 1991 and 2001, reveals that the object was in the decline from an outburst in 1992 and again in outburst in 2001. A distance of d = 170+/-30 pc is obtained from a method similar to that used to constrain the distance to open clusters. From this distance, disc radial brightness temperature distributions are determined, and the disc temperatures remain below the critical effective temperature T_{crit} at all disc radii during the outburst. The distributions in quiescence and in outburst are significantly different from those of other dwarf novae of similar orbital period. These results cannot be explained within the framework of the disc instability model and the small amplitude outbursts of V4140 Sgr can be due bursts of enhanced mass transfer rate from the secondary star. Our HT Cas data consist of V and R CCD photometric observations done in 2005 November with the 0.95-m James Gregory Telescope (JGT) and cover a outburst cycle. We used the entropy associated to the eclipse maps to obtain the semi-opening disc angle α evolution throught the outburst. The obtained angles are systematically lower than those obtained by Ioannou et al. (1999) and we can conclude that the outburst radial profiles must be flatter than the the T ∝ r^{-3/4} law of steady state dics, against the expectations of the disc instability model. Our intensity radial distributions presents the same ``outside-in'' outburst behavior as obtained by the referred author.

  8. STELLAR BINARY COMPANIONS TO SUPERNOVA PROGENITORS

    SciTech Connect

    Kochanek, Christopher S.

    2009-12-20

    For typical models of binary statistics, 50%-80% of core-collapse supernova (ccSN) progenitors are members of a stellar binary at the time of the explosion. Independent of any consequences of mass transfer, this has observational consequences that can be used to study the binary properties of massive stars. In particular, the secondary companion to the progenitor of a Type Ib/c SN is frequently (approx50%) the more optically luminous star since the high effective temperatures of the stripped progenitors make it relatively easy for a lower luminosity, cooler secondary to emit more optical light. Secondaries to the lower mass progenitors of Type II SN will frequently produce excess blue emission relative to the spectral energy distribution of the red primary. Available data constrain the models weakly. Any detected secondaries also provide an independent lower bound on the progenitor mass and, for historical SN, show that it was not a Type Ia event. Bright ccSN secondaries have an unambiguous, post-explosion observational signature-strong, blueshifted, relatively broad absorption lines created by the developing SN remnant (SNR). These can be used to locate historical SN with bright secondaries, confirm that a source is a secondary, and, potentially, measure abundances of ccSN ejecta. Luminous, hot secondaries will re-ionize the SNR on timescales of 100-1000 yr that are faster than re-ionization by the reverse shock, creating peculiar H II regions due to the high metallicity and velocities of the ejecta.

  9. INFRARED SPECTROSCOPY OF SYMBIOTIC STARS. IX. D-TYPE SYMBIOTIC NOVAE

    SciTech Connect

    Hinkle, Kenneth H.; Joyce, Richard R.; Fekel, Francis C.; Wood, Peter E-mail: joyce@noao.edu E-mail: wood@mso.anu.edu.au

    2013-06-10

    Time-series spectra of the near-infrared 1.6 {mu}m region have been obtained for five of the six known D-type symbiotic novae. The spectra map the pulsation kinematics of the Mira component in the Mira-white dwarf binary system and provide the center-of-mass velocity for the Mira. No orbital motion is detected in agreement with previous estimates of orbital periods {approx}>100 yr and semimajor axes {approx}50 AU. The 1-5 {mu}m spectra of the Miras show line weakening during dust obscuration events. This results from scattering and continuum emission by 1000 K dust. In the heavily obscured HM Sge system the 4.6 {mu}m CO spectrum formed in 1000 K gas is seen in emission against an optically thick dust continuum. Spectral features that are typically produced in either the cool molecular region or the expanding circumstellar region of late-type stars cannot be detected in the D-symbiotic novae. This is in accord with the colliding wind model for interaction between the white dwarf and Mira. Arguments are presented that the 1000 K gas and dust are not Mira circumstellar material but are in the wind interaction region of the colliding winds. CO is the first molecule detected in this region. We suggest that dust condensing in the intershock region is the origin of the dust obscuration. This model explains variations in the obscuration. Toward the highly obscured Mira in HM Sge the dust zone is estimated to be {approx}0.1 AU thick. The intershock wind interaction zone appears thinnest in the most active systems. Drawing on multiple arguments masses are estimated for the system components. The Miras in most D-symbiotic novae have descended from intermediate mass progenitors. The large amount of mass lost from the Mira combined with the massive white dwarf companion suggests that these systems are supernova candidates. However, timescales and the number of objects make these rare events.

  10. Summary of Stimulated Raman Scattering Experiments in the Nova Air-Path and Projected Nova and Nova II System Performance Limits

    SciTech Connect

    Henesian, M; Swift, C D; Murray, J R

    2007-07-17

    The authors present the results of high intensity beam propagation experiments conducted with the Nova laser system to investigate the occurrence of stimulated rotational Raman scattering (SRRS) from atmospheric nitrogen in the beam path. Enclosed is a preprint entitled ''Stimulated Rotational Raman Scattering in Nitrogen in Long Air Paths'' that they have published in the November issue of Optics Letters. The physics issues associated with SRRS are discussed at length in the preprint. The small signal steady-state SRRS gain coefficient that they determined from threshold measurements is in excellent agreement with recent direct SRRS gain measurements by Bischel, et al., at SRI, and is in good agreement with early gain estimates from Averbakh, et al., in the Soviet Union. Consequently, they have a high degree of confidence in the gain coefficient. In addition, threshold SRRS experiments on the long air-path Nova II system are in substantial agreement with the earlier Nova experiments. Nova and Nova II system performance limitations were not critically addressed in the publication so they shall discuss these issues in this paper.

  11. Circulating and tissue resident endothelial progenitor cells.

    PubMed

    Basile, David P; Yoder, Mervin C

    2014-01-01

    Progenitor cells for the endothelial lineage have been widely investigated for more than a decade, but continue to be controversial since no unique identifying marker has yet been identified. This review will begin with a discussion of the basic tenets originally proposed for proof that a cell displays properties of an endothelial progenitor cell. We then provide an overview of the methods for putative endothelial progenitor cell derivation, expansion, and enumeration. This discussion includes consideration of cells that are present in the circulation as well as cells resident in the vascular endothelial intima. Finally, we provide some suggested changes in nomenclature that would greatly clarify and demystify the cellular elements involved in vascular repair.

  12. A synthetic niche for nephron progenitor cells.

    PubMed

    Brown, Aaron C; Muthukrishnan, Sree Deepthi; Oxburgh, Leif

    2015-07-27

    FGF, BMP, and WNT balance embryonic nephron progenitor cell (NPC) renewal and differentiation. By modulating these pathways, we have created an in vitro niche in which NPCs from embryonic kidneys or derived from human embryonic stem cells can be propagated. NPC cultures expanded up to one billion-fold in this environment can be induced to form tubules expressing nephron differentiation markers. Single-cell culture reveals phenotypic variability within the early CITED1-expressing NPC compartment, indicating that it is a mixture of cells with varying progenitor potential. Furthermore, we find that the developmental age of NPCs does not correlate with propagation capacity, indicating that cessation of nephrogenesis is related to factors other than an intrinsic clock. This in vitro nephron progenitor niche will have important applications for expansion of cells for engraftment and will facilitate investigation of mechanisms that determine the balance between renewal and differentiation in these cells. PMID:26190145

  13. Exploring the Progenitors of Fast Radio Bursts

    NASA Astrophysics Data System (ADS)

    Burke-Spolaor, Sarah; Kramer, Michael; Bhat, Ramesh; Kulkarni, S. R.; Keller, Stefan; Champion, David; Flynn, Chris; Kasliwal, Mansi

    2014-10-01

    Fast Radio Bursts (FRBs) are millisecond bursts that are broadly evidenced to arise from extragalactic, but yet unknown, progenitors. They have presented a true mystery in that so far no progenitor theory can adequately account for their observed properties. We request observations that will glean basic information on FRB progenitors. Our observations will execute a specific test of whether FRBs originate in nearby galaxies. We have also designed our target field and time request to enable a thorough exploration of optical counterparts before, during, and after any detected FRB episode. Additionally, with a number depending on the typical distance to FRBs, our observations will raise the running list of total FRB discoveries by 10-60%.

  14. Endothelial progenitor cells in cardiovascular diseases.

    PubMed

    Lee, Poay Sian Sabrina; Poh, Kian Keong

    2014-07-26

    Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells (EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vasculogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk factors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardiovascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evaluate the challenges facing EPC research and how these may be overcome.

  15. Progenitor cells in the adult pancreas.

    PubMed

    Holland, Andrew M; Góñez, L Jorge; Harrison, Leonard C

    2004-01-01

    The beta-cell mass in the adult pancreas possesses the ability to undergo limited regeneration following injury. Identifying the progenitor cells involved in this process and understanding the mechanisms leading to their maturation will open new avenues for the treatment of type 1 diabetes. However, despite steady advances in determining the molecular basis of early pancreatic development, the identification of pancreatic stem cells or beta-cell progenitors and the molecular mechanisms underlying beta-cell regeneration remain unclear. Recent advances in the directed differentiation of embryonic and adult stem cells has heightened interest in the possible application of stem cell therapy in the treatment of type 1 diabetes. Drawing on the expanding knowledge of pancreas development, beta-cell regeneration and stem cell research, this review focuses on progenitor cells in the adult pancreas as a potential source of beta-cells. PMID:14737742

  16. WHT, DIPOL-2 polarimetry of Nova Sgr 2015b

    NASA Astrophysics Data System (ADS)

    Harvey, Eamonn; Berdyugin, Andrei; Redman, Matt

    2015-09-01

    We report polarimetry data from three nights observing of Nova Sgr 2015b (also PNV J18365700-2855420 or V5668 Sgr) with the William Herschel Telescope in the BVR passbands using the DIPOL-2 instrument.

  17. Life after eruption - I. Spectroscopic observations of 10 nova candidates

    NASA Astrophysics Data System (ADS)

    Tappert, C.; Ederoclite, A.; Mennickent, R. E.; Schmidtobreick, L.; Vogt, N.

    2012-07-01

    We have started a project to investigate the connection of post-novae with the population of cataclysmic variables (CVs). Our first steps in this concern improving the sample of known post-novae and their properties. Here we present the recovery and/or confirmation of the old novae MT Cen, V812 Cen, V655 CrA, IL Nor, V2109 Oph, V909 Sgr, V2572 Sgr and V728 Sco. Principal photometric and spectroscopic properties of these systems are discussed. We find that V909 Sgr is a probable magnetic CV, and that V728 Sco is a high-inclination system. We furthermore suggest that the two candidate novae V734 Sco and V1310 Sgr have been misclassified and instead are Mira variables. Based on observations with ESO telescopes, proposal numbers 083.D-0158, 086.D-0428 and 087.D-0323.

  18. Ocean and Coastal Acidification off New England and Nova Scotia

    EPA Science Inventory

    New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acid...

  19. A Comprehensive Review of Nova-Like Variable Stars

    NASA Astrophysics Data System (ADS)

    Sion, Edward

    2016-07-01

    A comprehensive review of nova-like variable stars of the VY Sculptoris and UX Ursa Majoris subtypes is presented. All that has been learned, up to the present time, from observations in the X-ray, far ultraviolet, optical and infrared bandpasses will be discussed. Spectroscopic analyses of high optical brightness states and low optical brightness states of nova-like variables will be summarized. The application of standard and non-standard accretion disk models as well as boundary layer structure will be discussed. The results of searches for nova shells, the evolutionary state of nova-likes as well as new spectroscopic results on BZ Cam (the bow shock CV) and BB Dor will also be included. This work is supported by NASA ADP grants NNX13AF12G and NNX13AF11G to Villanova University.

  20. Extensions developed for NOVA/Husky cloud point equation

    SciTech Connect

    Seglin, L. )

    1988-10-24

    Extensions have been developed for the NOVA/Husky cloud point equation that improve the determination of constants for the equation, and optimize the use of available distillate fractions for producing diesel fuels with acceptable cloud points.

  1. AAS Nova and Astrobites: Making current astronomy research accessible

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna; Astrobites Team

    2016-10-01

    AAS Nova and Astrobites are two resources available for astronomers, astronomy students, and astronomy enthusiasts to keep up with some of the most recent research published across the field of astronomy. Both supported by the AAS, these two daily astrophysical literature blogs provide accessible summaries of recent publications on the arXiv and in AAS journals. We present the goals, content, and readership of AAS Nova and Astrobites, and discuss how they might be used as tools in the undergraduate classroom.

  2. Spectroscopic confirmation of the dwarf nova nature of GR Orionis

    NASA Astrophysics Data System (ADS)

    Arai, Akira; Nogami, Daisaku

    2013-02-01

    We spectroscopically observed GR Ori with the 2.0-m Nayuta Telescope at Nishi-Harima Astronomical Observatory on 2013 February 13. This observation was carried out with the low resolution mode (R~1,000) of the optical spectrograph MALLS which covers the wavelength of 4,000-6,800 A. GR Ori was discovered as a possible nova in 1916 (Thiele 1916, Astron. Nachr., 202, 213), but has long been suspected to be a dwarf nova (e.g.

  3. Optical observations of KT Eri = Nova Eridani 2009

    NASA Astrophysics Data System (ADS)

    Ragan, E.; Brozek, T.; Suchomska, K.; Skalbania, A.; Konorski, P.; Galan, C.; Swierczynski, E.; Tomov, T.; Mikolajewski, M.; Wychudzki, P.

    2009-12-01

    We report on optical observations of Nova Eri 2009 obtained at the Nicolaus Copernicus University Observatory (Torun, Poland) and the Olsztyn Planetarium and Astronomical Observatory. Using a 60 cm Cassegrain telescope (Torun) and a 25 cm Schmidt-Cassegrain telescope (Olsztyn) we estimated the V brightness of the Nova to ~8.30+/-0.04 mag and ~8.59+/-0.01 mag on Nov. 27.00 UT and Nov. 27.91 UT.

  4. Resident mesenchymal progenitors of articular cartilage

    PubMed Central

    Candela, Maria Elena; Yasuhara, Rika; Iwamoto, Masahiro; Enomoto-Iwamoto, Motomi

    2015-01-01

    Articular cartilage has poor capacity of self-renewal and repair. Insufficient number and activity of resident mesenchymal (connective tissue) progenitors is likely one of the underlying reasons. Chondroprogenitors reside not only in the superficial zone of articular cartilage but also in other zones of articular cartilage and in the neighboring tissues, including perichondrium (groove of Ranvier), synovium and fat pad. These cells may respond to injury and contribute to articular cartilage healing. In addition, marrow stromal cells can migrate through subchondral bone when articular cartilage is damaged. We should develop drugs and methods that correctly stimulate resident progenitors for improvement of repair and inhibition of degenerative changes in articular cartilage. PMID:25179676

  5. Resident mesenchymal progenitors of articular cartilage.

    PubMed

    Candela, Maria Elena; Yasuhara, Rika; Iwamoto, Masahiro; Enomoto-Iwamoto, Motomi

    2014-10-01

    Articular cartilage has poor capacity of self-renewal and repair. Insufficient number and activity of resident mesenchymal (connective tissue) progenitors is likely one of the underlying reasons. Chondroprogenitors reside not only in the superficial zone of articular cartilage but also in other zones of articular cartilage and in the neighboring tissues, including perichondrium (groove of Ranvier), synovium and fat pad. These cells may respond to injury and contribute to articular cartilage healing. In addition, marrow stromal cells can migrate through subchondral bone when articular cartilage is damaged. We should develop drugs and methods that correctly stimulate resident progenitors for improvement of repair and inhibition of degenerative changes in articular cartilage. PMID:25179676

  6. Endothelial progenitor cells--an evolving story.

    PubMed

    Pearson, Jeremy D

    2010-05-01

    The first description of endothelial progenitor cells (EPC) in 1997 led rapidly to substantial changes in our understanding of angiogenesis, and within 5 years to the first clinical studies in humans using bone marrow derived EPC to enhance coronary neovascularisation and cardiac function after myocardial ischemia. However, to improve the success of this therapy a clearer understanding of the biology of EPC is needed. This article summarises recent data indicating that most EPC are not, in fact, endothelial progenitors but can be better described as angiogenic monocytes, and explores the implications this has for their future therapeutic use.

  7. Pigment Cell Progenitors in Zebrafish Remain Multipotent through Metamorphosis.

    PubMed

    Singh, Ajeet Pratap; Dinwiddie, April; Mahalwar, Prateek; Schach, Ursula; Linker, Claudia; Irion, Uwe; Nüsslein-Volhard, Christiane

    2016-08-01

    The neural crest is a transient, multipotent embryonic cell population in vertebrates giving rise to diverse cell types in adults via intermediate progenitors. The in vivo cell-fate potential and lineage segregation of these postembryonic progenitors is poorly understood, and it is unknown if and when the progenitors become fate restricted. We investigate the fate restriction in the neural crest-derived stem cells and intermediate progenitors in zebrafish, which give rise to three distinct adult pigment cell types: melanophores, iridophores, and xanthophores. By inducing clones in sox10-expressing cells, we trace and quantitatively compare the pigment cell progenitors at four stages, from embryogenesis to metamorphosis. At all stages, a large fraction of the progenitors are multipotent. These multipotent progenitors have a high proliferation ability, which diminishes with fate restriction. We suggest that multipotency of the nerve-associated progenitors lasting into metamorphosis may have facilitated the evolution of adult-specific traits in vertebrates. PMID:27453500

  8. Atypical dust species in the ejecta of classical novae

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    A classical nova outburst arises from a thermonuclear runaway in the hydrogen-rich material accreted onto the surface of a white dwarf in a binary system. These explosions can produce copious amounts of heavy element enriched material that are ejected violently into the surrounding interstellar medium. In some novae, conditions in the ejecta are suitable for the formation of dust of various compositions, including silicates, amorphous carbon, silicon carbide, and hydrocarbons. Multiple dust grain types are sometimes produced in the same system. CO formation in novae may not reach saturation, thus invalidating the usual paradigm in which the C:O ratio determines the dust species. A few novae, such as V705 Cas and DZ Cru, have exhibited emission features near 6, 8, and 11 μmthat are similar to "Unidentified Infrared" (UIR) features, but with significant differences in position and band structure. Here, we present Spitzer IRS spectra of two recent dusty novae, V2361 Cyg and V2362 Cyg, that harbor similar peculiar emission structures superimposed on features arising from carbonaceous grains. In other astronomical objects, such as star forming regions and young stellar objects, emission peaks at 6.2, 7.7, and 11.3 μmhave been associated with polycyclic aromatic hydrocarbon (PAH) complexes. We suggest that hydrogenated amorphous carbon (HAC) may be the source of these features in novae based upon the spectral behavior of the emission features and the conditions under which the dust formed.

  9. Evolution of Nova-Dependent Splicing Regulation in the Brain

    PubMed Central

    Živin, Marko; Darnell, Robert B

    2007-01-01

    A large number of alternative exons are spliced with tissue-specific patterns, but little is known about how such patterns have evolved. Here, we study the conservation of the neuron-specific splicing factors Nova1 and Nova2 and of the alternatively spliced exons they regulate in mouse brain. Whereas Nova RNA binding domains are 94% identical across vertebrate species, Nova-dependent splicing silencer and enhancer elements (YCAY clusters) show much greater divergence, as less than 50% of mouse YCAY clusters are conserved at orthologous positions in the zebrafish genome. To study the relation between the evolution of tissue-specific splicing and YCAY clusters, we compared the brain-specific splicing of Nova-regulated exons in zebrafish, chicken, and mouse. The presence of YCAY clusters in lower vertebrates invariably predicted conservation of brain-specific splicing across species, whereas their absence in lower vertebrates correlated with a loss of alternative splicing. We hypothesize that evolution of Nova-regulated splicing in higher vertebrates proceeds mainly through changes in cis-acting elements, that tissue-specific splicing might in some cases evolve in a single step corresponding to evolution of a YCAY cluster, and that the conservation level of YCAY clusters relates to the functions encoded by the regulated RNAs. PMID:17937501

  10. Recurrent Miller Fisher syndrome.

    PubMed

    Madhavan, S; Geetha; Bhargavan, P V

    2004-07-01

    Miller Fisher syndrome (MFS) is a variant of Guillan Barre syndrome characterized by the triad of ophthalmoplegia, ataxia and areflexia. Recurrences are exceptional with Miller Fisher syndrome. We are reporting a case with two episodes of MFS within two years. Initially he presented with partial ophthalmoplegia, ataxia. Second episode was characterized by full-blown presentation characterized by ataxia, areflexia and ophthalmoplegia. CSF analysis was typical during both episodes. Nerve conduction velocity study was fairly within normal limits. MRI of brain was within normal limits. He responded to symptomatic measures initially, then to steroids in the second episode. We are reporting the case due to its rarity.

  11. Recurrent respiratory papillomatosis.

    PubMed

    Venkatesan, Naren N; Pine, Harold S; Underbrink, Michael P

    2012-06-01

    Recurrent respiratory papillomatosis (RRP) is a rare, benign disease with no known cure. RRP is caused by infection of the upper aerodigestive tract with the human papillomavirus (HPV). Passage through the birth canal is thought to be the initial transmission event, but infection may occur in utero. HPV vaccines have helped to provide protection from cervical cancer; however, their role in the prevention of RRP is undetermined. Clinical presentation of initial symptoms of RRP may be subtle. RRP course varies, and current management focuses on surgical debulking of papillomatous lesions with or without concurrent adjuvant therapy. PMID:22588043

  12. ARAS Optical Spectroscopy of Classical Nova ASASSN-16ig (Nova Sgr 2016 no. 2)

    NASA Astrophysics Data System (ADS)

    Garde, Olivier; Charbonnel, Stephane; Du, Pascal Le

    2016-08-01

    We obtained a series of optical of the classical nova ASASSN-16ig in Sagittarius (N Sgr 2016 no. 2) (see ATels #9375, #9343, #9352, #9359, CBET 4295, 4299) with a LISA spectrograph plus ATIK414EX CCD using a C14 at Obs. Hautes Provence on Aug. 13.83 UT and 14.49 UT with total exposures of about 6000 sec each at a resolution of around 700 covering the interval 4000 - 7550 A with sufficient S/N ratio ( > 10). The spectra on both days are show the early optically thick "Fe curtain" stage of the ejecta expansion with the usual low ionization spectrum.

  13. Another neon nova - Early infrared photometry and spectroscopy of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hayward, T. L.; Gehrz, R. D.; Miles, J. W.; Houck, J. R.

    1992-01-01

    Infrared photometry and spectrophotometry of Nova Cygni 1992 taken within 54 days of its eruption show a strong 12.8-micron Ne II forbidden emission line as well as hydrogen recombination lines. Spectra with lambda/Delta lambda of about 2000 resolve the Ne II forbidden and 12.37-micron Hu-alpha lines with about 2200 km/s (FWHM). The Ne II forbidden line shows multiple velocity components. The amount of forbidden Ne II required to produce the observed emission feature exceeds the solar abundance of neon by at least a factor of 4.

  14. Recurrent renal giant leiomyosarcoma.

    PubMed

    Öziş, Salih Erpulat; Gülpınar, Kamil; Şahlı, Zafer; Konak, Baha Burak; Keskin, Mete; Özdemir, Süleyman; Ataoğlu, Ömür

    2016-01-01

    Primary renal leiomyosarcomas are rare, aggressive tumors. They constitute 1-2% of adult malignant renal tumors. Although leiomyosarcomas are the most common histological type (50-60%) of renal sarcomas, information on renal leiomyosarcoma is limited. Local or systemic recurrences are common. The radiological appearance of renal leiomyosarcomas is not specific, therefore renal leiomyosarcoma cannot be distinguished from renal cell carcinoma by imaging methods in all patients. A 74-year-old female patient presented to our clinic complaining of a palpable mass on the right side of her abdomen in November 2012. The abdominal magnetic resonance imaging revealed a mass, 25 × 24 × 23 cm in size. Her past medical history revealed that she has undergone right radical nephrectomy in 2007, due to a 11 × 12 × 13 cm renal mass that was then reported as renal cell carcinoma on abdominal magnetic resonance imaging, but the pathological diagnosis was low-grade renal leiomyosarcoma. The most recent follow-up of the patient was in 2011, with no signs of local recurrence or distant metastases within this four-year period. The patient underwent laparotomy on November 2012, and a 35 cm retroperitoneal mass was excised. The pathological examination of the mass was reported as high-grade leiomyosarcoma. The formation of this giant retroperitoneal mass in 1 year can be explained by the transformation of the lesion's pathology from low-grade to a high-grade tumor. PMID:27436926

  15. NOVA2-mediated RNA regulation is required for axonal pathfinding during development

    PubMed Central

    Saito, Yuhki; Miranda-Rottmann, Soledad; Ruggiu, Matteo; Park, Christopher Y; Fak, John J; Zhong, Ru; Duncan, Jeremy S; Fabella, Brian A; Junge, Harald J; Chen, Zhe; Araya, Roberto; Fritzsch, Bernd; Hudspeth, A J; Darnell, Robert B

    2016-01-01

    The neuron specific RNA-binding proteins NOVA1 and NOVA2 are highly homologous alternative splicing regulators. NOVA proteins regulate at least 700 alternative splicing events in vivo, yet relatively little is known about the biologic consequences of NOVA action and in particular about functional differences between NOVA1 and NOVA2. Transcriptome-wide searches for isoform-specific functions, using NOVA1 and NOVA2 specific HITS-CLIP and RNA-seq data from mouse cortex lacking either NOVA isoform, reveals that NOVA2 uniquely regulates alternative splicing events of a series of axon guidance related genes during cortical development. Corresponding axonal pathfinding defects were specific to NOVA2 deficiency: Nova2-/- but not Nova1-/- mice had agenesis of the corpus callosum, and axonal outgrowth defects specific to ventral motoneuron axons and efferent innervation of the cochlea. Thus we have discovered that NOVA2 uniquely regulates alternative splicing of a coordinate set of transcripts encoding key components in cortical, brainstem and spinal axon guidance/outgrowth pathways during neural differentiation, with severe functional consequences in vivo. DOI: http://dx.doi.org/10.7554/eLife.14371.001 PMID:27223325

  16. Quark nova imprint in the extreme supernova explosion SN 2006gy

    NASA Astrophysics Data System (ADS)

    Ouyed, R.; Kostka, M.; Koning, N.; Leahy, D. A.; Steffen, W.

    2012-06-01

    The extremely luminous supernova 2006gy (SN 2006gy) is among the most energetic ever observed. The peak brightness was 100 times that of a typical supernova and it spent an unheard of 250 d at magnitude -19 or brighter. Efforts to describe SN 2006gy have pushed the boundaries of current supernova theory. In this work we aspire to simultaneously reproduce the photometric and spectroscopic observations of SN 2006gy using a quark nova (QN) model. This analysis considers the supernova explosion of a massive star followed days later by the QN detonation of a neutron star. We lay out a detailed model of the interaction between the supernova envelope and the QN ejecta paying special attention to a mixing region which forms at the inner edge of the supernova envelope. This model is then fitted to photometric and spectroscopic observations of SN 2006gy. This QN model naturally describes several features of SN 2006gy including the late-stage light-curve plateau, the broad Hα line and the peculiar blue Hα absorption. We find that a progenitor mass between 20 and 40 M⊙ provides ample energy to power SN 2006gy in the context of a QN.

  17. Recurrence theorems: A unified account

    SciTech Connect

    Wallace, David

    2015-02-15

    I discuss classical and quantum recurrence theorems in a unified manner, treating both as generalisations of the fact that a system with a finite state space only has so many places to go. Along the way, I prove versions of the recurrence theorem applicable to dynamics on linear and metric spaces and make some comments about applications of the classical recurrence theorem in the foundations of statistical mechanics.

  18. Planar Rayleigh-Taylor experiments on Nova

    SciTech Connect

    Remington, B.A.; Haan, S.W.; Glendinning, S.G.; Kilkenny, J.D.; Wallace, R.J.

    1991-07-02

    We have performed experiments at the Nova Laser Facility to study surface perturbation growth on planar foils accelerated radiatively by a shaped x-ray drive. The experiments are designed to address in two dimensions the extent to which single-mode perturbations grow and multiple-mode perturbations couple to one another. Using a 22x magnification x-ray microscope in combination with a large are backlighter as our primary detector system, we have accelerated planar fluorosilicone (FS) foils and plastic foils doped with bromine (CH(Br)). Using face-on radiography, we have measured the growth of single-mode sinusoidal surface perturbations in an amplitude-scaling series with FS foils and in a wavelength-scaling series with CH(Br) foils. We have also measured the growth of a perturbation consisting of the superposition of two modes. Measurements in side-on geometry give the foil trajectory. Comparisons with 2-D computer simulations show generally good agreements, though results depend on the choice of opacity model. 21 refs., 9 figs.

  19. Recent results from the Nova experiments program

    SciTech Connect

    Kauffman, R.L.; Cable, M.D.; Campbell, E.M.; Glendinning, S.G.; Hatcher, C.W.; Hatchett, S.P.; Kania, D.R.; Kilkenny, J.D.; Kornblum, H.N.; Kyrazis, D.T.

    1988-10-01

    I review recent experimental results using the Nova laser. The experiments primarily address the physics of indirect-drive ICF. These experiments include investigating high-Z plasmas and radiation production, hydrodynamic stability, and high convergence implosions. The high-Z plasma experiments used a variety of targets to study the complex dynamics and ionization physics of high-Z plasmas. In long pulse irradiations of Au disks with 0.35-..mu..m light, x-ray conversion efficiencies greater than 70% have been demonstrated. In collaboration with AWE, we have quantitatively measured material mix at an unstable accelerated interface. In other experiments, we have observed growth of modulations due to Rayleigh-Taylor instabilities in accelerated samples. Radiation-driven implosions experiments have demonstrated radial convergences of 30 fold with good agreement with one-dimensional hydrodynamic simulations. Presently these experiments are limited to about 20 kJ of 0.35-..mu..m light due to damage in the amplifier glass. We are presently installing new amplifier glass which will allow routine operation at 120 kJ of 1..omega.. light in a 2.5-ns pulse. In addition, we are significantly increasing our ability to measure and control the laser pulse shape. With these improvements, we will be able to perform high-power pulse-shaped experiments needed for high density implosions. 2 refs., 4 figs.

  20. A nebula around Nova BT Monocerotis

    NASA Technical Reports Server (NTRS)

    Marsh, T. R.; Oke, J. B.; Wade, R. A.

    1983-01-01

    H-alpha observations of Nova BT Mon obtained on December 15, 1981 using an 800x800-pixel CCD detector on the double spectrograph of the 5-m Hale telescope at Palomar Observatory are reported. The reciprocal dispersion at H-alpha was 6.04 A/pixel and the angular scale along the 1.0-arcsec-wide east-west slit was 0.58 arcsec/pixel; resolution of the combined, processed image is about 12 A. A ring-shaped nebular emission with a center displaced slightly from the stellar image and an expansion distance to BT Mon of about 1800 pc was detected. The velocity diameter is found to be about 1500 km/sec along the ridge line and 2100 km/sec along the 10-unit contour. The mass of the visible nebula is estimated as 0.00003 solar mass, similar to the BT Mon ejection mass determined by Schaefer and Patterson (1983).

  1. X-Ray Nova Light Curves

    NASA Astrophysics Data System (ADS)

    Shrader, Chris; Titarchuk, Lev

    2002-04-01

    We describe recent work in which we revisit the database of historical X-Ray nova (XRN) light curves compiled by Chen, Shrader & Livio (1997, ApJ 491, 312), augmented by subsequent events recorded by RXTE, in an attempt to gain a better understanding of the outburst phenomenon. Previously, we demonstrated that, given the occurrence of an instability in the mass transfer rate from the secondary, a model based on viscous diffusion of matter through the disk (Wood et al, 2001, astro-ph/0108189) we could reproduce a large number of fast-rise exponential decay (FRED) type XRN light curves. We augment this effort by considering deviations from the FRED form, such as plateaus and power-law decay forms are also considered within this framework. More complex structures are, in a number of instances, successfully modeled as a superposition of mass- injection, diffusive propagation events. In addition, for a large number of cases, we perform a joint analysis of optical light curve data. In particular, we will attempt to characterize empirical characteristics such as possible tie lags, and relative decay time scales, and then interpret such effects withing the context of diffusive propagation in the disk.

  2. Supernova experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B.A.; Glendinning, S.G.; Wallace, R.; Rubenchik, A.; Fryxell, B.A.

    1997-12-02

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in [l]. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov and Rayleigh-Taylor instabilities as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. New analysis of the bubble velocity is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of SN 1987A.

  3. Supernova Experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Bazan, G.; Drake, R. P.; Fryxell, B. A.

    2000-04-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported by Kane et al. in a recent paper. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmeyer-Meshkov instability, and to the Rayleigh-Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few times 10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. We also present new analysis of the bubble velocity, a study of two-dimensional versus three-dimensional difference in growth at the He-H interface of SN 1987A, and designs for two-dimensional versus three-dimensional hydro experiments. (c) 2000 The American Astronomical Society.

  4. Proteoglycan synthesis by hematopoietic progenitor cells

    SciTech Connect

    Minguell, J.J.; Tavassoli, M. )

    1989-05-15

    The synthesis of proteoglycans (PG) by hematopoietic stromal cells has been reported. But PG synthesis by hematopoietic progenitor cells has not been explored. We have studied synthesis, cellular distribution, and molecular characteristics of PG by a cloned interleukin-3 (IL-3)-dependent hematopoietic progenitor cell line, FDCP-1, which is cloned from murine long-term marrow cultures. Under appropriate conditions the cell can differentiate into granulocytes and macrophages, and therefore, can be considered CFU-GM equivalent. The pattern of PG synthesis was studied by 35SO4 labeling. FDCP-1 cells actively synthesize PG, which are distributed in the intracellular, membrane-associated (MP), and extracellular pools. After purification of the 35S-labeled material by ion-exchange and gel filtration techniques, a single chondroitin sulfate-PG (CIS-PG) was observed to be present in the three studied pools. By Sepharose CL-4B chromatography, this PG has a Kav of 0.47, which after alkaline treatment is shifted to a Kav of 0.67. This indicates the proteoglycan nature of the 35SO4-labeled material. The MP CIS-PG is not stable. It is released to the culture medium where it is subsequently processed. However, in the presence of hematopoietic stromal cells D2X, the stability of MP proteoglycan of FDCP-1 cells is enhanced, suggesting that the synthesis of PG by progenitor cells and its accumulation in the membrane may have a role in the interaction between progenitor and stromal cells.

  5. Psychosocial adjustment to recurrent cancer.

    PubMed

    Mahon, S M; Cella, D F; Donovan, M I

    1990-01-01

    This descriptive study of the perceptions and needs of people with recurrent malignancies asks three questions: How do patients describe the meaning of a recurrence of cancer? Do individuals perceive the diagnosis of recurrence and the initial diagnosis of cancer differently? What are the key psychosocial problems associated with recurrent cancer? The theoretical framework was based on Lazarus and Folkman's theory of stress, appraisal, and coping. Subjects completed the Impact of Event Scale (IES), the Psychosocial Adjustment to Illness Scale--Self-Report (PAIS), and a semistructured qualitative interview. The interview elicited perceptions of the event of recurrence and differences between the diagnosis of recurrence and the initial diagnosis. The convenience sample included 40 patients diagnosed with recurrent cancer within the last 30 days. Many subjects (78%) reported that the recurrence was more upsetting than the initial diagnosis. Scores on both the IES and the PAIS were high when compared to normative samples of patients with cancer suggesting that this sample of patients experienced a lot of psychological distress as well as problems at home, work, and in their social lives. These concerns often were unknown to caregivers. Although more research is needed, the authors propose that, with more accurate assessment, more effective intervention could be implemented and the quality of life improved for patients with recurrent cancer.

  6. SUPERNOVA REMNANT PROGENITOR MASSES IN M31

    SciTech Connect

    Jennings, Zachary G.; Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.; Fouesneau, Morgan; Weisz, Daniel R.; Murphy, Jeremiah W.; Dolphin, Andrew E. E-mail: adolphin@raytheon.com

    2012-12-10

    Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M{sub ZAMS}) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star, then assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the M{sub ZAMS} from this age. Because our technique is not contingent on identification or precise location of the progenitor star, it can be applied to the location of any known SNRs. We identify significant young star formation around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of {approx}2 increase over currently measured progenitor masses. We consider the remaining six SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped their birth sites. In general, the distribution of recovered progenitor masses is bottom-heavy, showing a paucity of the most massive stars. If we assume a single power-law distribution, dN/dM{proportional_to}M{sup {alpha}}, then we find a distribution that is steeper than a Salpeter initial mass function (IMF) ({alpha} = -2.35). In particular, we find values of {alpha} outside the range -2.7 {>=} {alpha} {>=} -4.4 to be inconsistent with our measured distribution at 95% confidence. If instead we assume a distribution that follows a Salpeter IMF up to some maximum mass, then we find that values of M{sub Max} > 26 are inconsistent with the measured distribution at 95% confidence. In either scenario, the data suggest that some fraction of massive stars may not explode. The result is preliminary and requires more SNRs and further analysis. In addition, we use our distribution to estimate a

  7. Abemaciclib in Children With DIPG or Recurrent/Refractory Solid Tumors

    ClinicalTrials.gov

    2016-04-12

    Diffuse Intrinsic Pontine Glioma; Brain Tumor, Recurrent; Solid Tumor, Recurrent; Neuroblastoma, Recurrent, Refractory; Ewing Sarcoma, Recurrent, Refractory; Rhabdomyosarcoma, Recurrent, Refractory; Osteosarcoma, Recurrent, Refractory; Rhabdoid Tumor, Recurrent, Refractory

  8. Isolation of Dendritic Cell Progenitor and Bone Marrow Progenitor Cells from Mouse.

    PubMed

    Onai, Nobuyuki; Ohteki, Toshiaki

    2016-01-01

    Dendritic cells (DCs) comprise two major subsets, conventional DC (cDC) and plasmacytoid DC (pDC) in the steady-state lymphoid organ. These cells have a short half-life and therefore, require continuous generation from hematopoietic stem cells and progenitor cells. Recently, we identified DC-restricted progenitors called common DC progenitors (CDPs) in the bone marrow of mouse. The CDPs can be isolated from mouse bone marrow based on the hematopoietic cytokine receptors, such as Flt3 (Fms-related tyrosine kinase 3) (CD135), c-kit (CD117), M-CSF (macrophage colony-stimulating factor) receptor (CD115), and IL-7 (interleukin-7) receptor-α (CD127). The CDPs comprise of two progenitors, CD115(+) CDPs and CD115(-) CDPs, and give rise to only DC subsets in both in vitro and in vivo. The former CDPs are the main source of cDC, while the later CDPs are the main source of pDC in vivo. Here, we provide a protocol for the isolation of dendritic cell progenitor and bone marrow progenitor cells from mouse. PMID:27142008

  9. Thermal stability and nova cycles in permanent superhump systems

    NASA Astrophysics Data System (ADS)

    Retter, A.; Naylor, T.

    2000-12-01

    Archival data on permanent superhump systems are compiled to test the thermal stability of their accretion discs. We find that their discs are almost certainly thermally stable as expected. This result confirms Osaki's suggestion that permanent superhump systems form a new subclass of cataclysmic variables (CVs), with relatively short orbital periods and high mass-transfer rates. We note that if the high accretion rates estimated in permanent superhump systems represent their mean secular values, then their mass-transfer rates cannot be explained by gravitational radiation, therefore, either magnetic braking should be extrapolated to systems below the period gap or they must have mass-transfer cycles. Alternatively, a new mechanism that removes angular momentum from CVs below the gap should be invoked. We suggest applying the nova cycle scenarios offered for systems above the period gap to the short orbital period CVs. Permanent superhumps have been observed in the two non-magnetic ex-novae with binary periods below the gap. Their post-nova magnitudes are brighter than their pre-outburst values. In one case (V1974 Cyg) it has been demonstrated that the pre-nova should have been a regular SU UMa system. Thus, it is the first nova whose accretion disc was observed to change its thermal stability. If the superhumps in this system indicate persistent high mass-transfer rates rather than a temporary change induced by irradiation from the hot post-nova white dwarf, it is the first direct evidence for mass-transfer cycles in CVs. The proposed cycles are driven by the nova eruption.

  10. Recurrent ovarian cancer.

    PubMed

    Pujade-Lauraine, E; Combe, P

    2016-04-01

    Recurrence still occurs in a majority of patients with advanced ovarian cancer. However, progress in the management has allowed a significant prolongation of survival for relapsing disease. These last years, the field of interest has moved from chemotherapy to targeted therapy which is dominated by anti-angiogenic and anti-PARP agents. It is assumed that platinum-free interval will not remain the main prognostic and predictive criterion in the future, and will be replaced by a multi-factorial approach. This trend for personalization of therapy has highlighted important neglected fields for clinical research such as multi-line (≥3) relapse, frail patients including elderly and symptomatic and supportive measures. PMID:27141075

  11. Recurrent vulvovaginal candidiasis.

    PubMed

    Sobel, Jack D

    2016-01-01

    Recurrent vulvovaginal candidiasis (RVVC) is a common cause of significant morbidity in women in all strata of society affecting millions of women worldwide. Previously, RVVC occurrence was limited by onset of menopause but the widespread use of hormone replacement therapy has extended the at-risk period. Candida albicans remains the dominant species responsible for RVVC, however optimal management of RVVC requires species determination and effective treatment measures are best if species-specific. Considerable progress has been made in understanding risk factors that determine susceptibility to RVVC, particularly genetic factors, as well as new insights into normal vaginal defense immune mechanisms and their aberrations in RVVC. While effective control of RVVC is achievable with the use of fluconazole maintenance suppressive therapy, cure of RVVC remains elusive especially in this era of fluconazole drug resistance. Vaccine development remains a critical challenge and need.

  12. Na-22 decay gamma rays from classical novae

    NASA Technical Reports Server (NTRS)

    Truran, James W.

    1993-01-01

    NASA Grant NAG 5-1565 has provided support for a program of theoretical research in nuclear astrophysics and related areas, focusing upon the possibility of detecting gamma rays from nearby novae. Particular attention has been given to the evaluation of the theoretical expectations for gamma ray emission from four possible sources: (1) the positron decays of the unstable CNO and fluorine isotopes that are transported to the surface regions of the envelope in the earliest stages of the outbursts; (2) Be-7 decay gamma rays, (3) Na-22 decay gamma rays released in the later stages of the outbursts; and (4) Al-26 decay gamma rays from novae and their possible contribution to Galactic emission. The critical questions of (1) the frequency of occurrence of ONeMg-enriched novae; (2) the expected Galactic distribution of the novae that produce 26Al; and (3) the nature of the observed soft X-ray emission from classical novae, have also been addressed. Considerable progress in research has been achieved on many of these fronts. Brief summaries of the results of several research projects are presented.

  13. Evaluating local food programs: the case of Select Nova Scotia.

    PubMed

    Knight, Andrew J

    2013-02-01

    This study evaluated the effectiveness of the buy local food program Select Nova Scotia; a government program with the goal to increase awareness and consumption of Nova Scotia produced and processed agri-food products by Nova Scotians and visitors. The evaluation methodology was based on prior evaluation resources and local food consumer research. Data were gathered through a web panel survey; 877 respondents completed the survey in June 2010. The results suggest that the program is reaching a wider audience than just those predisposed to local food initiatives. In addition, awareness of Select Nova was related to perceptions of local benefits and barriers, as well as purchase motivation and behavior. Respondents who were aware of Select Nova Scotia rated societal benefits as more important and viewed location and price as less of a barrier; they were also more likely to be highly motivated to purchase local foods. This study also informs results found in previous consumer research studies and identifies marketing opportunities to enhance the effectiveness of local food programs. The results suggest that societal benefits might be used as a way to differentiate products with similar attributes.

  14. Galactic constraints on supernova progenitor models

    NASA Astrophysics Data System (ADS)

    Acharova, I. A.; Gibson, B. K.; Mishurov, Yu. N.; Kovtyukh, V. V.

    2013-09-01

    Aims: To estimate the mean masses of oxygen and iron ejected per each type of supernovae (SNe) event from observations of the elemental abundance patterns in the Galactic disk and constrain the relevant SNe progenitor models. Methods: We undertake a statistical analysis of the radial abundance distributions in the Galactic disk within a theoretical framework for Galactic chemical evolution which incorporates the influence of spiral arms. This framework has been shown to recover the non-linear behaviour in radial gradients, the mean masses of oxygen and iron ejected during SNe explosions to be estimated, and constraints to be placed on SNe progenitor models. Results: (i) The mean mass of oxygen ejected per core-collapse SNe (CC SNe) event (which are concentrated within spiral arms) is ~0.27 M⊙; (ii) the mean mass of iron ejected by tardy Type Ia SNe (SNeIa, whose progenitors are older/longer-lived stars with ages ≳100 Myr and up to several Gyr, which do not concentrate within spiral arms) is ~0.58 M⊙; (iii) the upper mass of iron ejected by prompt SNeIa (SNe whose progenitors are younger/shorter-lived stars with ages ≲100 Myr, which are concentrated within spiral arms) is ≤0.23 M⊙ per event; (iv) the corresponding mean mass of iron produced by CC SNe is ≤0.04 M⊙ per event; (v) short-lived SNe (core-collapse or prompt SNeIa) supply ~85% of the Galactic disk's iron. Conclusions: The inferred low mean mass of oxygen ejected per CC SNe event implies a low upper mass limit for the corresponding progenitors of ~23 M⊙, otherwise the Galactic disk would be overabundant in oxygen. This inference is the consequence of the non-linear dependence between the upper limit of the progenitor initial mass and the mean mass of oxygen ejected per CC SNe explosion. The low mean mass of iron ejected by prompt SNeIa, relative to the mass produced by tardy SNeIa (~2.5 times lower), prejudices the idea that both sub-populations of SNeIa have the same physical nature. We

  15. Sall1 in renal stromal progenitors non-cell autonomously restricts the excessive expansion of nephron progenitors.

    PubMed

    Ohmori, Tomoko; Tanigawa, Shunsuke; Kaku, Yusuke; Fujimura, Sayoko; Nishinakamura, Ryuichi

    2015-10-29

    The mammalian kidney develops from reciprocal interactions between the metanephric mesenchyme and ureteric bud, the former of which contains nephron progenitors. The third lineage, the stroma, fills up the interstitial space and is derived from distinct progenitors that express the transcription factor Foxd1. We showed previously that deletion of the nuclear factor Sall1 in nephron progenitors leads to their depletion in mice. However, Sall1 is expressed not only in nephron progenitors but also in stromal progenitors. Here we report that specific Sall1 deletion in stromal progenitors leads to aberrant expansion of nephron progenitors, which is in sharp contrast with a nephron progenitor-specific deletion. The mutant mice also exhibited cystic kidneys after birth and died before adulthood. We found that Decorin, which inhibits Bmp-mediated nephron differentiation, was upregulated in the mutant stroma. In contrast, the expression of Fat4, which restricts nephron progenitor expansion, was reduced mildly. Furthermore, the Sall1 protein binds to many stroma-related gene loci, including Decorin and Fat4. Thus, the expression of Sall1 in stromal progenitors restricts the excessive expansion of nephron progenitors in a non-cell autonomous manner, and Sall1-mediated regulation of Decorin and Fat4 might at least partially underlie the pathogenesis.

  16. Recurrence plots and recurrence quantification analysis of human motion data

    NASA Astrophysics Data System (ADS)

    Josiński, Henryk; Michalczuk, Agnieszka; Świtoński, Adam; Szczesna, Agnieszka; Wojciechowski, Konrad

    2016-06-01

    The authors present exemplary application of recurrence plots, cross recurrence plots and recurrence quantification analysis for the purpose of exploration of experimental time series describing selected aspects of human motion. Time series were extracted from treadmill gait sequences which were recorded in the Human Motion Laboratory (HML) of the Polish-Japanese Academy of Information Technology in Bytom, Poland by means of the Vicon system. Analysis was focused on the time series representing movements of hip, knee, ankle and wrist joints in the sagittal plane.

  17. Nova outbursts in the case of mild hibernation

    SciTech Connect

    Livio, M.; Shankar, A.; Truran, J.W.

    1988-02-01

    The necessary conditions for the production of strong thermonuclear runaways in the hibernation scenario are identified and explored. It is found that a reduction in the accretion rate by a factor of about 100, for a period longer than a few thousand years, is generally sufficient to ensure nova-type outbursts, even in the presence of rather high preoutburst accretion rates. Nova outbursts can be obtained under mild hibernation conditions on 1 solar mass white dwarfs as well as on very massive ones. A reduction in the accretion rate by a factor of 10 only is insufficient to produce a nova outburst, if the preoutburst accretion rate is as high as 10 to the -8th solar mass/yr. 28 references.

  18. Calibration of the NOvA Far Detector

    NASA Astrophysics Data System (ADS)

    Sachdev, Kanika

    2014-03-01

    NOvA, currently under construction, is a long-baseline neutrino oscillation experiment that will use the NuMI beam originating at Fermilab. NOvA enables the study of two oscillation channels: νμ disappearance and νe appearance and their CP conjugates. It consists of two functionally identical detectors; the Near Detector (ND) at FNAL is 100 m underground and the Far Detector (FD) near International Falls in Northern Minnesota is on the surface. The modular design of the detectors allows us to commission and calibrate sections of the detectors independently of others. The location of the FD on surface facilitates the use of cosmic rays as a tool to calibrate it. This talk will describe the methods used to calibrate the NOvA far detector.

  19. Model Atmospheres for Novae in Outburst: Summary of Research

    NASA Technical Reports Server (NTRS)

    Hauschildt, Peter H.

    1999-01-01

    This paper presents a final report and summary of research on Model Atmospheres for Novae in Outburst. Some of the topics include: 1) Detailed NLTE (non-local thermodynamic equilibrium) Model Atmospheres for Novae during Outburst: II. Modeling optical and ultraviolet observations of Nova LMC 1988 #1; 2) A Non-LTE Line-Blanketed Stellar Atmosphere Model of the Early B Giant epsilon CMa; 3) Spectroscopy of Low Metallicity Stellar atmospheres; 4) Infrared Colors at the Stellar/Substellar Boundary; 5) On the abundance of Lithium in T CrB; 6) Numerical Solution of the Expanding Stellar Atmosphere Problem; and 7) The NextGen Model Atmosphere grid for 3000 less than or equal to T (sub eff) less than or equal to 10000K.

  20. Multi-Dimensional Modeling of Nova with Realistic Nuclear Physics

    SciTech Connect

    Zingale, M; Hoffman, R D

    2011-01-27

    This contract covered the period from 03/09/2010 to 09/30/2010. Over this period, we adapted the low Mach number hydrodynamics code MAESTRO to perform simulations of novae. A nova is the thermonuclear runaway of an accreted hydrogen layer on the surface of a white dwarf. As the accreted layer grows in mass, the temperature and density at the base increase to the point where hydrogen fusion can begin by the CNO cycle - a burning process that uses carbon, nitrogen, and oxygen to complete the fusion of four hydrogen nuclei into one helium-4 nucleus. At this point, we are running initial models of nova, exploring the details of the convection. In the follow-on contract to this one, we will continue this investigation.

  1. Ultrastructure of extrusomes in hypotrichous ciliate Pseudourostyla nova

    NASA Astrophysics Data System (ADS)

    Zhou, Yao; Wang, Zhengjun; Zhang, Jun; Gu, Fukang

    2011-01-01

    The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell.

  2. A radial velocity study of the dwarf nova TZ Persei

    NASA Astrophysics Data System (ADS)

    Ringwald, F. A.

    1995-05-01

    A radial velocity study of the Hα emission line of the dwarf nova TZ Per is presented. TZ Per has a spectroscopic period of 6.2520+/-0.0096h. With this period and published JHK photometry, a distance of >~380 pc is inferred. This Z Cam star has both slow outbursts and a short outburst cycle, and time-resolved spectra were obtained on both the rise and the decline of a dwarf nova outburst. TZ Per does not obey the relation between orbital period and outburst decline time found by Bailey and calibrated by Szkody & Mattei. This is probably because the disc is hot all the time, relative to dwarf novae such as U Gem or SS Cyg.

  3. Nova Monocerotis 2012 = PNV J06393874+0553520

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2012-08-01

    The discovery is reported of Nova Monocerotis 2012 = PNV J06393874+0553520 by Shigehisa Fujikawa (Kanonji City, Kagawa Prefecture, Japan, reported by Mitsuru Soma, National Astronomical Observatory of Japan) at magnitude C=9.4 on 2012 Aug. 09.8048 UT. Coordinates: 06 39 38.74 +05 53 52.0 (2000.0). Spectroscopy by multiple teams indicate a classical nova evolving toward the nebular phase. Announced on IAU CBAT Central Bureau Electronic Telegram 3202 (Daniel W. E. Green, ed.). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details, particularly regarding spectra and nearby stars, and observations of Nova Mon 2012 already reported to the AAVSO.

  4. Hematopoietic progenitor migration to the adult thymus

    PubMed Central

    Zlotoff, Daniel A.; Bhandoola, Avinash

    2010-01-01

    While most hematopoietic lineages develop in the bone marrow (BM), T cells uniquely complete their development in the specialized environment of the thymus. Hematopoietic stem cells with long-term self-renewal capacity are not present in the thymus. As a result, continuous T cell development requires that BM-derived progenitors be imported into the thymus throughout adult life. The process of thymic homing begins with the mobilization of progenitors out of the bone marrow, continues with their circulation in the bloodstream, and concludes with their settling in the thymus. This review will discuss each of these steps as they occur in the unirradiated and post-irradiation scenarios, focusing on the molecular mechanisms of regulation. Improved knowledge about these early steps in T cell generation may accelerate the development of new therapeutic options in patients with impaired T cell number or function. PMID:21251013

  5. Noninvasive Imaging of Administered Progenitor Cells

    SciTech Connect

    Steven R Bergmann, M.D., Ph.D.

    2012-12-03

    The objective of this research grant was to develop an approach for labeling progenitor cells, specifically those that we had identified as being able to replace ischemic heart cells, so that the distribution could be followed non-invasively. In addition, the research was aimed at determining whether administration of progenitor cells resulted in improved myocardial perfusion and function. The efficiency and toxicity of radiolabeling of progenitor cells was to be evaluated. For the proposed clinical protocol, subjects with end-stage ischemic coronary artery disease were to undergo a screening cardiac positron emission tomography (PET) scan using N-13 ammonia to delineate myocardial perfusion and function. If they qualified based on their PET scan, they would undergo an in-hospital protocol whereby CD34+ cells were stimulated by the administration of granulocytes-colony stimulating factor (G-CSF). CD34+ cells would then be isolated by apharesis, and labeled with indium-111 oxine. Cells were to be re-infused and subjects were to undergo single photon emission computed tomography (SPECT) scanning to evaluate uptake and distribution of labeled progenitor cells. Three months after administration of progenitor cells, a cardiac PET scan was to be repeated to evaluate changes in myocardial perfusion and/or function. Indium oxine is a radiopharmaceutical for labeling of autologous lymphocytes. Indium-111 (In-111) decays by electron capture with a t{sub ½} of 67.2 hours (2.8 days). Indium forms a saturated complex that is neutral, lipid soluble, and permeates the cell membrane. Within the cell, the indium-oxyquinolone complex labels via indium intracellular chelation. Following leukocyte labeling, ~77% of the In-111 is incorporated in the cell pellet. The presence of red cells and /or plasma reduces the labeling efficacy. Therefore, the product needed to be washed to eliminate plasma proteins. This repeated washing can damage cells. The CD34 selected product was a 90

  6. Interneuron Progenitor Transplantation to Treat CNS Dysfunction

    PubMed Central

    Chohan, Muhammad O.; Moore, Holly

    2016-01-01

    Due to the inadequacy of endogenous repair mechanisms diseases of the nervous system remain a major challenge to scientists and clinicians. Stem cell based therapy is an exciting and viable strategy that has been shown to ameliorate or even reverse symptoms of CNS dysfunction in preclinical animal models. Of particular importance has been the use of GABAergic interneuron progenitors as a therapeutic strategy. Born in the neurogenic niches of the ventral telencephalon, interneuron progenitors retain their unique capacity to disperse, integrate and induce plasticity in adult host circuitries following transplantation. Here we discuss the potential of interneuron based transplantation strategies as it relates to CNS disease therapeutics. We also discuss mechanisms underlying their therapeutic efficacy and some of the challenges that face the field. PMID:27582692

  7. Progenitor cells for ocular surface regenerative therapy.

    PubMed

    Casaroli-Marano, Ricardo P; Nieto-Nicolau, Nuria; Martínez-Conesa, Eva M

    2013-01-01

    The integrity and normal function of the corneal epithelium are essential for maintaining the cornea's transparency and vision. The existence of a cell population with progenitor characteristics in the limbus maintains a dynamic of constant epithelial repair and renewal. Currently, cell-based therapies for bio-replacement, such as cultured limbal epithelial transplantation and cultured oral mucosal epithelial transplantation, present very encouraging clinical results for treating limbal stem cell deficiencies. Another emerging therapeutic strategy consists of obtaining and implementing human progenitor cells of different origins using tissue engineering methods. The development of cell-based therapies using stem cells, such as human adult mesenchymal stromal cells, represents a significant breakthrough in the treatment of certain eye diseases and also offers a more rational, less invasive and more physiological approach to ocular surface regeneration. PMID:23257987

  8. POPULATION SYNTHESIS AND GAMMA RAY BURST PROGENITORS

    SciTech Connect

    C. L. FREYER

    2000-12-11

    Population synthesis studies of binaries are always limited by a myriad of uncertainties from the poorly understood effects of binary mass transfer and common envelope evolution to the many uncertainties that still remain in stellar evolution. But the importance of these uncertainties depends both upon the objects being studied and the questions asked about these objects. Here I review the most critical uncertainties in the population synthesis of gamma-ray burst progenitors. With a better understanding of these uncertainties, binary population synthesis can become a powerful tool in understanding, and constraining, gamma-ray burst models. In turn, as gamma-ray bursts become more important as cosmological probes, binary population synthesis of gamma-ray burst progenitors becomes an important tool in cosmology.

  9. Progenitor cells for ocular surface regenerative therapy.

    PubMed

    Casaroli-Marano, Ricardo P; Nieto-Nicolau, Nuria; Martínez-Conesa, Eva M

    2013-01-01

    The integrity and normal function of the corneal epithelium are essential for maintaining the cornea's transparency and vision. The existence of a cell population with progenitor characteristics in the limbus maintains a dynamic of constant epithelial repair and renewal. Currently, cell-based therapies for bio-replacement, such as cultured limbal epithelial transplantation and cultured oral mucosal epithelial transplantation, present very encouraging clinical results for treating limbal stem cell deficiencies. Another emerging therapeutic strategy consists of obtaining and implementing human progenitor cells of different origins using tissue engineering methods. The development of cell-based therapies using stem cells, such as human adult mesenchymal stromal cells, represents a significant breakthrough in the treatment of certain eye diseases and also offers a more rational, less invasive and more physiological approach to ocular surface regeneration.

  10. Human progenitor cells for bone engineering applications.

    PubMed

    de Peppo, G M; Thomsen, P; Karlsson, C; Strehl, R; Lindahl, A; Hyllner, J

    2013-06-01

    In this report, the authors review the human skeleton and the increasing burden of bone deficiencies, the limitations encountered with the current treatments and the opportunities provided by the emerging field of cell-based bone engineering. Special emphasis is placed on different sources of human progenitor cells, as well as their pros and cons in relation to their utilization for the large-scale construction of functional bone-engineered substitutes for clinical applications. It is concluded that, human pluripotent stem cells represent a valuable source for the derivation of progenitor cells, which combine the advantages of both embryonic and adult stem cells, and indeed display high potential for the construction of functional substitutes for bone replacement therapies.

  11. The endocannabinoid system drives neural progenitor proliferation.

    PubMed

    Aguado, Tania; Monory, Krisztina; Palazuelos, Javier; Stella, Nephi; Cravatt, Benjamin; Lutz, Beat; Marsicano, Giovanni; Kokaia, Zaal; Guzmán, Manuel; Galve-Roperh, Ismael

    2005-10-01

    The discovery of multipotent neural progenitor (NP) cells has provided strong support for the existence of neurogenesis in the adult brain. However, the signals controlling NP proliferation remain elusive. Endocannabinoids, the endogenous counterparts of marijuana-derived cannabinoids, act as neuromodulators via presynaptic CB1 receptors and also control neural cell death and survival. Here we show that progenitor cells express a functional endocannabinoid system that actively regulates cell proliferation both in vitro and in vivo. Specifically, NPs produce endocannabinoids and express the CB1 receptor and the endocannabinoid-inactivating enzyme fatty acid amide hydrolase (FAAH). CB1 receptor activation promotes cell proliferation and neurosphere generation, an action that is abrogated in CB1-deficient NPs. Accordingly, proliferation of hippocampal NPs is increased in FAAH-deficient mice. Our results demonstrate that endocannabinoids constitute a new group of signaling cues that regulate NP proliferation and thus open novel therapeutic avenues for manipulation of NP cell fate in the adult brain.

  12. Nova V2362 Cygni (Nova Cygni 2006): Spitzer, Swift, and Ground-Based Spectral Evolution

    NASA Technical Reports Server (NTRS)

    Lynch, David K.; Venturini, Catherine C.; Mazuk, S.; Woodward, Charles; Gehrz, Robert; Rayner, John; Helton, L.A.; Ness, Jan-Uwe; Starrfield, Sumner; Rudy, Richard J.; Russell, Ray W.; Osborne, Julian P.; Page, Kim; Pearson, Richard; Wagner, R. Mark; Puetter, Richard C.; Perry, Raleigh B.; Schwarz, Greg; Vanlandingham, Karen; Black, John; Bode, Michael; Evans, Aneurin; Geballe, Thomas; Greenhouse, Matthew; Hauschildt, Peter

    2008-01-01

    Nova V2362 Cygni has undergone a number of very unusual changes. Ground-based spectroscopy initially revealed a normal sequence of events: the object faded and its near-infrared emission lines gradually shifted to higher excitation conditions until about day 100 when the optical fading reversed and the object slowly brightened. This was accompanied by a rise in the Swift X-ray telescope flux and a sudden shift in excitation of the visible and IR spectrum back to low levels. The new lower excitation spectrum revealed broad line widths and many P-Cygni profiles, all indicative of the ejection of a second shell. Eventually, dust formed, the X-ray brightness -- apparently unaffected by dust formation -- peaked and then declined, and the object faded at all wavelengths. The Spitzer dust spectra revealed a number of solid-state emission features that, at this time, are not identified.

  13. Multipotent Hematopoietic Progenitors Divide Asymmetrically to Create Progenitors of the Lymphomyeloid and Erythromyeloid Lineages

    PubMed Central

    Görgens, André; Ludwig, Anna-Kristin; Möllmann, Michael; Krawczyk, Adalbert; Dürig, Jan; Hanenberg, Helmut; Horn, Peter A.; Giebel, Bernd

    2014-01-01

    Summary Hematopoietic stem and progenitor cells (HSPCs) can self-renew and create committed progenitors, a process supposed to involve asymmetric cell divisions (ACDs). Previously, we had linked the kinetics of CD133 expression with ACDs but failed to detect asymmetric segregation of classical CD133 epitopes on fixed, mitotic HSPCs. Now, by using a novel anti-CD133 antibody (HC7), we confirmed the occurrence of asymmetric CD133 segregation on paraformaldehyde-fixed and living HSPCs. After showing that HC7 binding does not recognizably affect biological features of human HSPCs, we studied ACDs in different HSPC subtypes and determined the developmental potential of arising daughter cells at the single-cell level. Approximately 70% of the HSPCs of the multipotent progenitor (MPP) fraction studied performed ACDs, and about 25% generated lymphoid-primed multipotent progenitor (LMPP) as wells as erythromyeloid progenitor (EMP) daughter cells. Since MPPs hardly created daughter cells maintaining MPP characteristics, our data suggest that under conventional culture conditions, ACDs are lineage instructive rather than self-renewing. PMID:25448068

  14. EVOLUTION OF PROGENITORS FOR ELECTRON CAPTURE SUPERNOVAE

    SciTech Connect

    Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi E-mail: umeda@astron.s.u-tokyo.ac.jp

    2013-07-01

    We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor electron capture nuclei using a large nuclear reaction network with updated reaction rates. For electron capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M{sub Sun} and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor electron capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, electron capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

  15. Endothelial progenitor cells in hematologic malignancies

    PubMed Central

    Saulle, Ernestina; Castelli, Germana; Pelosi, Elvira

    2016-01-01

    Studies carried out in the last years have improved the understanding of the cellular and molecular mechanisms controlling angiogenesis during adult life in normal and pathological conditions. Some of these studies have led to the identification of some progenitor cells that sustain angiogenesis through indirect, paracrine mechanisms (hematopoietic angiogenic cells) and through direct mechanisms, i.e., through their capacity to generate a progeny of phenotypically and functionally competent endothelial cells [endothelial colony forming cells (ECFCs)]. The contribution of these progenitors to angiogenetic processes under physiological and pathological conditions is intensively investigated. Angiogenetic mechanisms are stimulated in various hematological malignancies, including chronic myeloid leukemia (CML), acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma, resulting in an increased angiogenesis that contributes to disease progression. In some of these conditions there is preliminary evidence that some endothelial cells could derive from the malignant clone, thus leading to the speculation that the leukemic cell derives from the malignant transformation of a hemangioblastic progenitor, i.e., of a cell capable of differentiation to the hematopoietic and to the endothelial cell lineages. Our understanding of the mechanisms underlying increased angiogenesis in these malignancies not only contributed to a better knowledge of the mechanisms responsible for tumor progression, but also offered the way for the discovery of new therapeutic targets. PMID:27583252

  16. Endothelial progenitor cells in hematologic malignancies.

    PubMed

    Testa, Ugo; Saulle, Ernestina; Castelli, Germana; Pelosi, Elvira

    2016-01-01

    Studies carried out in the last years have improved the understanding of the cellular and molecular mechanisms controlling angiogenesis during adult life in normal and pathological conditions. Some of these studies have led to the identification of some progenitor cells that sustain angiogenesis through indirect, paracrine mechanisms (hematopoietic angiogenic cells) and through direct mechanisms, i.e., through their capacity to generate a progeny of phenotypically and functionally competent endothelial cells [endothelial colony forming cells (ECFCs)]. The contribution of these progenitors to angiogenetic processes under physiological and pathological conditions is intensively investigated. Angiogenetic mechanisms are stimulated in various hematological malignancies, including chronic myeloid leukemia (CML), acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma, resulting in an increased angiogenesis that contributes to disease progression. In some of these conditions there is preliminary evidence that some endothelial cells could derive from the malignant clone, thus leading to the speculation that the leukemic cell derives from the malignant transformation of a hemangioblastic progenitor, i.e., of a cell capable of differentiation to the hematopoietic and to the endothelial cell lineages. Our understanding of the mechanisms underlying increased angiogenesis in these malignancies not only contributed to a better knowledge of the mechanisms responsible for tumor progression, but also offered the way for the discovery of new therapeutic targets. PMID:27583252

  17. NOVA: A new multi-level logic simulator

    NASA Technical Reports Server (NTRS)

    Miles, L.; Prins, P.; Cameron, K.; Shovic, J.

    1990-01-01

    A new logic simulator that was developed at the NASA Space Engineering Research Center for VLSI Design was described. The simulator is multi-level, being able to simulate from the switch level through the functional model level. NOVA is currently in the Beta test phase and was used to simulate chips designed for the NASA Space Station and the Explorer missions. A new algorithm was devised to simulate bi-directional pass transistors and a preliminary version of the algorithm is presented. The usage of functional models in NOVA is also described and performance figures are presented.

  18. Bipolar gas outflow from the nova V458 Vul

    NASA Astrophysics Data System (ADS)

    Goranskij, V. P.; Barsukova, E. A.; Fatkhullin, T. A.

    2010-06-01

    Classical nova V458 Vul (N Vul 2007 No.1) was detected as a supersoft X-ray source by the Swift XRT (ATel#1246, #1603). This star is interesting with its spectral class change: features of Fe II class nova completely changed by features of He/N class in the SSS phase (T.N. Tarasova, IBVS No.5807). We performed spectral observations of V458 Vul with the Russian 6-m telescope BTA and spectral camera SCORPIO on 2010 June 9.84 UT.

  19. The Orbital Period of the Classical Nova V458 Vul

    NASA Astrophysics Data System (ADS)

    Goranskij, V. P.; Metlova, N. V.; Barsukova, E. A.; Burenkov, A. N.; Soloviev, V. Ya.

    2008-07-01

    Classical nova V458 Vul (N Vul 2007 No.1) was detected as a supersoft X-ray source (SSS) by the Swift XRT several times in the time range between 2007 October 18 and 2008 June 18 (J. Drake et al., ATel #1246 and #1603). Our V photometry shows the plateau in the light curve continued since January till June 2008. This feature accompanies usually the SSS phases in some classical novae. The fragmentary monitoring during plateau shows night- to-night variability with the amplitudes between 1.2 and 0.4 mag and rapid variability by 0.1 mag in the time scale of an hour.

  20. White dwarf heating and the ultraviolet flux in dwarf novae

    NASA Technical Reports Server (NTRS)

    Pringle, J. E.

    1988-01-01

    The heating of the outer layers of the white dwarf which is likely to occur during a dwarf nova outburst is investigated. It is shown that the decline in IUE flux, observed during quiescent intervals in the dwarf novae VW Hydri and WX Hydri, may be due to the outer layers cooling off once the heat source is removed. The calculations here assume uniformity of the heat source over the white dwarf surface. This is unlikely to be realized from disk accretion, and discussion is made of what further calculations are required.

  1. IUE observations of the 1981 outburst of nova Cr A

    NASA Technical Reports Server (NTRS)

    Sparks, W. M.; Starrfield, S.; Wyckoff, S.; Williams, R. E.; Rruran, J. W.; Ney, E. P.

    1982-01-01

    Low dispersion spectrum observations are analyzed. The light curve of nova Cr A, indicating a moderately fast nova, is presented. Flux calibrated, merged spectrum graphs of April 21, 1981 and September 13, 1981 are presented, demonstrating very strong lines of Al and Si. Additional strong C, Ni, O, and Ne emission lines were identified. Emission lines due to highly ionized species such as Mg VII and Al Vl were observed for short times in May and June 1981. Preliminary analysis of spectra obtained 200 days after maximum indicate that the nebula is still in transition and has not yet reached the nebula state. An over abundance of N and Ne are suggested.

  2. Optical photometry and spectroscopy of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

    2013-08-01

    We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

  3. Nova V2467 Cyg as possible intermediate polar

    NASA Astrophysics Data System (ADS)

    Swierczynski, E.; Ragan, E.; Galan, C.; Mikolajewski, M.

    2008-09-01

    We report the results of 8 nights of unfiltered and RI band CCD photometry of the fast nova V2467Cyg (Nova Cyg 2007). The observations were carried out from 26 June to 8 July 2008 with the 60cm Cassegrain telescope of the Nicolaus Copernicus University Observatory (Torun, Poland). In total we collected 5683 frames during about 20 hours of observations. The magnitudes estimated on July 25.94 UT were B=16.10, V=14.71, R=14.19, I=13.67.

  4. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  5. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  6. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  7. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  8. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  9. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  10. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  11. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  12. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  13. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  14. NovaNET User Manual for C-Router Instructors. Second Edition Revised.

    ERIC Educational Resources Information Center

    Fortner, Monica B.; Davis, Dennis M.

    The NovaNET computer system is a mainframe system with a large network of users sharing the same computer. This manual is intended to teach instructors how to use the NovaNET system to deliver instruction to their students. The manual is divided into four main sections, each of which teaches a group of skills needed by NovaNET instructors. The…

  15. A low-mass-ratio and deep contact binary as the progenitor of the merger V1309 Sco

    NASA Astrophysics Data System (ADS)

    Zhu, Li-Ying; Zhao, Er-Gang; Zhou, Xiao

    2016-04-01

    Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact binary. It is the first stellar merger that was identified to be undergoing a common envelope transient. To understand the properties of its binary progenitor, the pre-outburst light curves were analyzed by using the W-D method. The photometric solution of the 2002 light curve shows that it is a deep contact binary (f = 89.5(±40.5)%) with a mass ratio of 0.094. The asymmetry of the light curve is explained by the presence of a dark spot on the more massive component. The extremely high fill-out factor suggests that the merging of the contact binary is driven by dynamical mass loss from the outer Lagrange point. However, the analysis of the 2004 light curve indicates that no solutions were obtained even at an extremely low mass ratio of q = 0.03. This suggests that the common convective envelope of the binary system disappeared and the secondary component spiraled into the envelope of the primary in 2004. Finally, the ejection of the envelope of the primary produced the outburst.

  16. Presence of a putative tumor-initiating progenitor cell population predicts poor prognosis in smokers with non-small cell lung cancer

    PubMed Central

    Ooi, Aik T.; Mah, Vei; Nickerson, Derek W.; Gilbert, Jennifer L.; Ha, Vi Luan; Hegab, Ahmed E.; Horvath, Steve; Alavi, Mohammad; Maresh, Erin L.; Chia, David; Gower, Adam C.; Lenburg, Marc E.; Spira, Avrum; Solis, Luisa M.; Wistuba, Ignacio I.; Walser, Tonya C.; Wallace, William D.; Dubinett, Steven M.; Goodglick, Lee; Gomperts, Brigitte N.

    2010-01-01

    Smoking is the most important known risk factor for the development of lung cancer. Tobacco exposure results in chronic inflammation, tissue injury and repair. A recent hypothesis argues for a stem/progenitor cell involved in airway epithelial repair that may be a tumor-initiating cell in lung cancer, and which may be associated with recurrence and metastasis. We used immunostaining, quantitative real-time PCR, Western blots and lung cancer tissue microarrays to identify subpopulations of airway epithelial stem/progenitor cells under steady state conditions, normal repair, aberrant repair with premalignant lesions and lung cancer and their correlation with injury and prognosis. We identified a population of keratin 14 (K14)-expressing progenitor epithelial cells that was involved in repair after injury. Dysregulated repair resulted in persistence of K14+ cells in the airway epithelium in premalignant lesions. The presence of K14+ cells in non-small cell lung cancer (NSCLC) samples predicted poorer outcomes. This was especially true in smokers where the presence of K14+ cells in NSCLC was predictive of metastasis. The presence of K14+ progenitor airway epithelial cells in NSCLC predicted a poor prognosis and this predictive value was strongest in smokers, where it also correlated with metastasis. This suggests that reparative K14+ progenitor cells may be tumor-initiating cells in this subgroup of smokers with NSCLC. PMID:20710044

  17. Recurrent Wheezing in Infants

    PubMed Central

    Belhassen, Manon; De Blic, Jacques; Laforest, Laurent; Laigle, Valérie; Chanut-Vogel, Céline; Lamezec, Liliane; Brouard, Jacques; Fauroux, Brigitte; de Pouvourville, Gérard; Ginoux, Marine; Van Ganse, Eric

    2016-01-01

    Abstract Recurrent wheezing (RW) has a significant impact on infants, caregivers, and society, but morbidity and related medical resource utilization (MRU) have not been thoroughly explored. The burden of RW needs to be documented with population-based data. The objective was to assess the characteristics, medical management, and MRU of RW infants identified from national claims data. Infants aged from 6 to 24 months, receiving ≥2 dispensations of respiratory drugs within 3 months, and presenting a marker of poor control (index date), were selected. During the 6 months after index date, MRU was described in the cohort and among 3 subgroups with more severe RW, defined as ≥4 dispensations of respiratory drugs, ≥3 dispensations of oral corticosteroids (OCS), or ≥1 hospitalization for respiratory symptoms. A total of 115,489 infants had RW, corresponding to 8.2% of subjects in this age group. During follow-up, 68.7% of infants received inhaled corticosteroids, but only 1.8 U (unit) were dispensed over 6 months, suggesting discontinuous use. Control was mostly inadequate: 61.7% of subjects received OCS, 80.2% antibiotics, and 71.2% short-acting beta-agonists, and medical/paramedical visits were numerous, particularly for physiotherapy. Severe RW concerned 39.0% of the cohort; 32.8% and 11.7% of infants had repeated use of respiratory drugs and OCS, respectively, and 5.5% were hospitalized for respiratory symptoms. In this real-life nation-wide study, RW was common and infants had poor control and high MRU. Interventions are needed to support adequate use of controller therapy, and to improve medical care. PMID:27082618

  18. WHITE DWARF/M DWARF BINARIES AS SINGLE DEGENERATE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Wheeler, J. Craig

    2012-10-20

    Limits on the companions of white dwarfs in the single-degenerate scenario for the origin of Type Ia supernovae (SNe Ia) have gotten increasingly tight, yet igniting a nearly Chandrasekhar mass C/O white dwarf from a condition of near hydrostatic equilibrium provides compelling agreement with observed spectral evolution. The only type of non-degenerate stars that survive the tight limits, M{sub V} {approx}> 8.4 on the SN Ia in SNR 0509-67.5 and M{sub V} {approx}> 9.5 in the remnant of SN 1572, are M dwarfs. While M dwarfs are observed in cataclysmic variables, they have special properties that have not been considered in most work on the progenitors of SNe Ia: they have small but finite magnetic fields and they flare frequently. These properties are explored in the context of SN Ia progenitors. White dwarf/M dwarf pairs may be sufficiently plentiful to provide, in principle, an adequate rate of explosions even with slow orbital evolution due to magnetic braking or gravitational radiation. Even modest magnetic fields on the white dwarf and M dwarf will yield adequate torques to lock the two stars together, resulting in a slowly rotating white dwarf, with the magnetic poles pointing at one another in the orbital plane. The mass loss will be channeled by a 'magnetic bottle' connecting the two stars, landing on a concentrated polar area on the white dwarf. This enhances the effective rate of accretion compared to spherical accretion. Luminosity from accretion and hydrogen burning on the surface of the white dwarf may induce self-excited mass transfer. The combined effects of self-excited mass loss, polar accretion, and magnetic inhibition of mixing of accretion layers give possible means to beat the 'nova limit' and grow the white dwarf to the Chandrasekhar mass even at rather moderate mass accretion rates.

  19. White Dwarf/M Dwarf Binaries as Single Degenerate Progenitors of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Wheeler, J. Craig

    2012-10-01

    Limits on the companions of white dwarfs in the single-degenerate scenario for the origin of Type Ia supernovae (SNe Ia) have gotten increasingly tight, yet igniting a nearly Chandrasekhar mass C/O white dwarf from a condition of near hydrostatic equilibrium provides compelling agreement with observed spectral evolution. The only type of non-degenerate stars that survive the tight limits, MV >~ 8.4 on the SN Ia in SNR 0509-67.5 and MV >~ 9.5 in the remnant of SN 1572, are M dwarfs. While M dwarfs are observed in cataclysmic variables, they have special properties that have not been considered in most work on the progenitors of SNe Ia: they have small but finite magnetic fields and they flare frequently. These properties are explored in the context of SN Ia progenitors. White dwarf/M dwarf pairs may be sufficiently plentiful to provide, in principle, an adequate rate of explosions even with slow orbital evolution due to magnetic braking or gravitational radiation. Even modest magnetic fields on the white dwarf and M dwarf will yield adequate torques to lock the two stars together, resulting in a slowly rotating white dwarf, with the magnetic poles pointing at one another in the orbital plane. The mass loss will be channeled by a "magnetic bottle" connecting the two stars, landing on a concentrated polar area on the white dwarf. This enhances the effective rate of accretion compared to spherical accretion. Luminosity from accretion and hydrogen burning on the surface of the white dwarf may induce self-excited mass transfer. The combined effects of self-excited mass loss, polar accretion, and magnetic inhibition of mixing of accretion layers give possible means to beat the "nova limit" and grow the white dwarf to the Chandrasekhar mass even at rather moderate mass accretion rates.

  20. Recurrence Quantification of Fractal Structures

    PubMed Central

    Webber, Charles L.

    2012-01-01

    By definition, fractal structures possess recurrent patterns. At different levels repeating patterns can be visualized at higher magnifications. The purpose of this chapter is threefold. First, general characteristics of dynamical systems are addressed from a theoretical mathematical perspective. Second, qualitative and quantitative recurrence analyses are reviewed in brief, but the reader is directed to other sources for explicit details. Third, example mathematical systems that generate strange attractors are explicitly defined, giving the reader the ability to reproduce the rich dynamics of continuous chaotic flows or discrete chaotic iterations. The challenge is then posited for the reader to study for themselves the recurrent structuring of these different dynamics. With a firm appreciation of the power of recurrence analysis, the reader will be prepared to turn their sights on real-world systems (physiological, psychological, mechanical, etc.). PMID:23060808

  1. Timing in the NOvA detectors with atomic clock based time transfers between Fermilab, the Soudan mine and the NOvA Far detector

    NASA Astrophysics Data System (ADS)

    Norman, A.; Niner, E.; Habig, A.

    2015-12-01

    The NOvA experiment uses a GPS based timing system both to internally synchronize the readout of the DAQ components and to establish an absolute wall clock reference which can be used to link the Fermilab accelerator complex with the neutrino flux that crosses the NOvA detectors. We describe the methods that were used during the commissioning of the NOvA DAQ and Timing systems to establish the synchronization between the Fermilab beam and the NOvA far detector. We present how high precision atomic clocks were trained and transported between the MINOS and NOvA detectors during a Northern Minnesota blizzard to validate the absolute time offsets of the experiments and make the first observation of beam neutrinos in the NOvA far detector.

  2. The recurrent carpal tunnel syndrome.

    PubMed

    Kern, B C; Brock, M; Rudolph, K H; Logemann, H

    1993-01-01

    Sixteen out of 720 patients with carpal tunnel syndrome who had undergone surgery since 1979 were reoperated for a "recurrence" (2.2%). Twelve of these patients had been originally operated on in our department. Thus, our own recurrence rate is 1.7%. Three patients deteriorated following surgery, 6 had an unsatisfactory improvement, and in 7 the symptoms recurred after initial improvement. Eight of the reoperated patients had a predisposing disease (terminal renal insufficiency, insulin-dependent diabetes mellitus, acromegaly). In 10 of the 16 cases the initial operation had been carried out by surgeons in the first three years of training. Reoperation revealed incomplete splitting of the transverse carpal ligament in 10 cases, compression of the median nerve by the scar in 4, injury of the muscular branch in 1, and an anatomical variant as cause of incomplete decompression in 1 patient. "Recurrences" after carpal tunnel surgery are predominantly due to inadequacies of the first procedure. A remarkable number of patients (50%) has predisposing diseases. Interfascicular or epineural neurolysis and complete exposure and neurolysis of the median nerve and its branches is necessary only in cases of recurrence. Their omission at the first surgery does not result in an increased recurrence rate. Our observations indicate that the number of operations for recurrent carpal tunnel syndrome can probably be reduced when the first operation is performed with care and experience. Patients with carpal tunnel syndrome secondary to a systemic disease are particularly at risk.

  3. The Nova Project in Secondary Teacher Education 1970-1973.

    ERIC Educational Resources Information Center

    Crum, Clyde; McCoy, Leone

    The Nova Project of the Department of Secondary Education at California State University, San Diego, is described in this report. This one-year preparation program for secondary school teachers combines school and community experience with the focus on a team approach. Faculty and students work with local school personnel in the joint planning,…

  4. Discovery of a Possible Nova in M31

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Wolf, M.

    2016-10-01

    We report the discovery of a possible nova in M31 on a co-added 1080-s R-band CCD frame taken on 2016 Oct. 7.758 UT with the 0.65-m telescope at Ondrejov. The object designated PNV J00420668+4105113 is located at R.A. = 0h42m06s.68, Decl.

  5. Internship and the Nova Scotia Government Experience. Case Study.

    ERIC Educational Resources Information Center

    Dodge, R. Bruce; McKeough, Mary

    2003-01-01

    Internship programs are traditionally seen as a social responsibility or means of screening potential employees. In a Nova Scotia government agency internship program, the agency benefitted in a different way: from the enthusiasm, fresh perspectives, and technology skills interns brought to the workplace. (SK)

  6. H-alpha confirmation of novae in M31

    NASA Astrophysics Data System (ADS)

    Ovcharov, E.; Nikolov, G.; Kostov, A.; Bozhilov, V.; Minev, M.; Valcheva, A.; Nedialkov, P.

    2015-08-01

    We report H-alpha and BR-band photometry of three objects in M31, suspected as novae. The objects are: PNV J00420640+4108211 = 2015-03a? (ATel# 7189), 2015-07c? (ATel# 7795, ATel #7818) and TCP J00401150+4042199 = 2015-07e? (ATel #7834).

  7. Optical and ultraviolet observations of nova Vul 1987

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Stryker, L. L.; Sonneborn, G.; Sparks, Warren M.; Wagner, R. M.; Ferland, Gary; Gallagher, J. S.; Wade, R.; Williams, R. E.; Gehrz, Robert D.

    1988-01-01

    The outburst for a nova discovered in Nov. 1987 and followed since then is summarized. Although it was possible to observe it with the IUE at maximum, its ultraviolet energy faded rapidly, and after the first 2 weeks it was impossible to observe it at IUE wavelengths. It is observed to form a thick dust shell and is in the nebular stage.

  8. NOvA: Building a Next Generation Neutrino Experiment

    ScienceCinema

    Perko, John; Williams, Ron; Miller, Bill

    2016-07-12

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  9. Discovery of an Apparent Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Alfaro, M. Diaz; Ordonez-Etxeberria, I.; Vaduvescu, O.

    2015-01-01

    We report the discovery of an apparent nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~2.4" seeing on 2015 Jan. 15.126 UT.

  10. Discovery of a Probable Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Mocnik, T.

    2014-09-01

    We report the discovery of a probable nova in M81 on a co-added 1440-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~2.2" seeing on 2014 Sep.

  11. Discovery of a Probable Nova in M33

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Tudor, V.

    2014-08-01

    We report the discovery of a probable nova in M33 on co-added 960-s narrow-band H-alpha and 480-s R-band CCD images taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.1" seeing on 2014 July 29.206 and 29.222 UT, respectively.

  12. The γ-ray sources in classical novae

    NASA Astrophysics Data System (ADS)

    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.

  13. Two new Galactic novae discovered in the VVV disk images

    NASA Astrophysics Data System (ADS)

    Pena, C. Contreras; Lucas, P. W.; Saito, R. K.; Minniti, D.; Kurtev, R.

    2016-04-01

    We report two novae in the Galactic plane discovered serendipitously during a search for high amplitude variable young stellar objects (Contreras Pena et al. 2016, arXiv:1602.06267) in the VVV Survey data (vvvsurvey.org; Minniti et al. 2010, New Astronomy, 15, 433).

  14. New studies of nuclear decay {gamma}-rays from novae

    SciTech Connect

    Starrfield, S.; Truran, J.W.; Wiescher, M.C.

    1997-11-01

    The cause of the nova outburst is a thermonuclear runaway (TNR) in hydrogen rich material transferred by a companion onto a white dwarf. Studies of this phenomenon have shown that the TNR produces large concentrations of the short lived positron unstable isotopes of the CNO nuclei which are transported to the surface by convection so that early in the outburst we expect significant numbers of radioactive decays to occur at the surface. The resulting {gamma}-ray emission may be detectable from nearby novae early in their outbursts. The TNR is also expected to produce substantial amounts of {sup 7}Be and {sup 22}Na. Their decays also yield potentially detectable levels of {gamma}-ray emission for relatively nearby novae. We are also interested in the role played by novae in the production of the {approximately}2M{circle_dot} of {sup 26}Al found in the galaxy. In order to improve our predictions of this phenomenon, we have performed a new set of calculations of TNR`s on ONeMg and CO white dwarfs with an updated nuclear reaction network and opacities.

  15. Pre-discovery confirmation of M81 nova candidate

    NASA Astrophysics Data System (ADS)

    Henze, M.; Sala, G.; Jose, J.; Figueira, J.; Hernanz, M.

    2016-10-01

    We confirm the discovery of a new nova candidate in the M81 galaxy (announced in ATel #9605) on 12x200s stacked R filter CCD images, obtained on 2016-10-08.05 UT. This date is 0.2 d prior to the discovery date given in ATel #9605.

  16. Grassroots Response to HIV/AIDS in Nova Scotia

    ERIC Educational Resources Information Center

    Plumb, Donovan

    2005-01-01

    This chapter describes how by adopting a cultural theory of learning, members of a community-based research team deepened their understanding of the nature, pervasiveness, and contribution of everyday learning processes of people affected by HIV/AIDS in Nova Scotia, Canada.

  17. Epidemiology of Lyme Disease, Nova Scotia, Canada, 2002–2013

    PubMed Central

    Johnston, B. Lynn; Schleihauf, Emily; Mask, Angela; Haldane, David; Drebot, Michael; Baikie, Maureen; Cole, Teri J.; Fleming, Sarah; Gould, Richard; Lindsay, Robbin

    2015-01-01

    Ixodes scapularis ticks, which transmit Borrelia burgdorferi, the causative agent of Lyme disease (LD), are endemic to at least 6 regions of Nova Scotia, Canada. To assess the epidemiology and prevalence of LD in Nova Scotia, we analyzed data from 329 persons with LD reported in Nova Scotia during 2002–2013. Most patients reported symptoms of early localized infection with rash (89.7%), influenza-like illness (69.6%), or both; clinician-diagnosed erythema migrans was documented for 53.2%. In a separate serosurvey, of 1,855 serum samples screened for antibodies to B. burgdorferi, 2 were borderline positive (both with an indeterminate IgG on Western blot), resulting in an estimated seroprevalence of 0.14% (95% CI 0.02%–0.51%). Although LD incidence in Nova Scotia has risen sharply since 2002 and is the highest in Canada (16/100,000 population in 2013), the estimated number of residents with evidence of infection is low, and risk is localized to currently identified LD-endemic regions. PMID:26401788

  18. NOvA: Building a Next Generation Neutrino Experiment

    SciTech Connect

    Perko, John; Williams, Ron; Miller, Bill

    2013-12-05

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  19. Maria Helena Novaes--Creative Person, Creative Life

    ERIC Educational Resources Information Center

    de Alencar, Eunice M. L. Soriano

    2014-01-01

    This article describes the characteristics and accomplishments of Maria Helena Novaes, one of the most creative school psychologists of Brazil. It identifies the people who influenced her and some of the factors that may have contributed to her achievements and rise to eminence. It highlights the numerous opportunities she received during her life…

  20. Hydrodynamic studies of oxygen, neon, and magnesium novae

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    Results are presented from recent theoretical studies that have examined the properties of nova outbursts on ONeMg white dwarfs. These outbursts are much more violent and occur much more frequently than outbursts on CO white dwarfs. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations.

  1. A SHORT DESCRIPTION OF THE PLAN OF NOVA HIGH SCHOOL.

    ERIC Educational Resources Information Center

    HIERS, NAN

    THE NOVA HIGH SCHOOL IS AN EDUCATIONAL EXPERIMENT TO MAKE LEARNING AND ACHIEVEMENT INTERESTING, CHALLENGING, AND EXCITING TO THE STUDENT. THE PROGRAM IS BASED ON THE CONCEPT OF INDIVIDUAL PROGRESS WITH EMPHASIS ON QUALITY EDUCATION. FEATURES OF THE SCHOOL ENVIRONMENT INCLUDE AIR-CONDITIONING, CARPETING, MULTIPURPOSE CLASSROOMS, INDIVIDUAL STUDY…

  2. Fotometria col filtro LPR alla nova V5668 SGR

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2016-09-01

    The nova SGR 2015 no. 2 or V5668 SGR was visually observed with the LPR filter to evaluate the OIII emission. The contributions of B, V, R and Visual components to the LPR magnitude are modeled and compared with the observations in scotopic vision.

  3. Progenitor Cells in Proximal Airway Epithelial Development and Regeneration

    PubMed Central

    Lynch, Thomas J.; Engelhardt, John F.

    2015-01-01

    Multiple distinct epithelial domains are found throughout the airway that are distinguishable by location, structure, function, and cell-type composition. Several progenitor cell populations in the proximal airway have been identified to reside in confined microenvironmental niches including the submucosal glands (SMGs), which are embedded in the tracheal connective tissue between the surface epithelium and cartilage, and basal cells that reside within the surface airway epithelium (SAE). Current research suggests that regulatory pathways that coordinate development of the proximal airway and establishment of progenitor cell niches may overlap with pathways that control progenitor cell responses during airway regeneration following injury. SMGs have been shown to harbor epithelial progenitor cells, and this niche is dysregulated in diseases such as cystic fibrosis. However, mechanisms that regulate progenitor cell proliferation and maintenance within this glandular niche are not completely understood. Here we discuss glandular progenitor cells during development and regeneration of the proximal airway and compare properties of glandular progenitors to those of basal cell progenitors in the SAE. Further investigation into glandular progenitor cell control will provide a direction for interrogating therapeutic interventions to correct aberrant conditions affecting the SMGs in diseases such as cystic fibrosis, chronic bronchitis, and asthma. PMID:24818588

  4. Measurement of Reactions on 30P for Nova Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Ma, Z.; Guidry, M. W.; Hix, W. R.; Smith, M. S.

    2003-05-01

    Replace these paragraphs with your abstract. We encourage you to include a sentence acknowledging your funding agency. In a recent study the 30P(p,gamma)31S rate played a crucial role in the synthesis of heavier nuclear species, from Si to Ca, in nova outbursts on ONe White Dwarfs [1]. The adopted rate of this reaction, based on a Hauser-Feshbach calculation [2], has a large uncertainty and could be as much as a factor of 100 too high or too low [3]. In their study, Jose et al.[1] varied the 30P(p,gamma)31S reaction rate within this uncertainty and found that, when rate is reduced by a factor of 100, the synthesis of elements above Si is lowered by a factor 10 with respect to the values found with the nominal rate. This has important consequences for nova nucleosynthesis, as overproduction of isotopes in the Si to Ca mass region has been observed in the ejecta from some nova explosions (e.g.,[4,5]). While generally valid at higher temperatures, Hauser-Feshbach calculations of the rates at nova temperatures can have large uncertainties. At these temperatures, the rate is more likely dominated by a few individual nuclear resonances. At present there are about 10 31S resonances known above the 30P + p threshold that may contribute to the 30P(p,gamma)31S reaction rate at nova temperatures. The excitation energies of these levels are known but spins and parities (for all but two) are not. We plan to measure the 30P(p,p)30P and 30P(p,gamma)31S reactions at HRIBF to better determine this reaction rate. A detailed description of the experiments will be given. We are also conducting a new nova nucleosynthesis simulation over multiple spatial zones of the exploding envelope to investigate the influence of the 30P(p,gamma)31S reaction rate on nova nucleosynthesis. The results of these calculations will be discussed. 1. Jose , J., Coc, A., Hernanz, M., Astrophys. J., 560, 897(2001). 2. Thielemann, F.-K et al., 1987, Advances in Nuclear Astrophysics, ed. E. Vangioni-Flam ( Gif

  5. [Recurrent spontaneous abortions].

    PubMed

    Salat-Baroux, J

    1988-01-01

    The process of fertilization in humans, is remarkably inefficient. Spontaneous abortion is estimated to be between 15 and 20% of all clinical pregnancies, and the early spontaneous abortion rate is closer to 30-50% of fertilized ova. Not all authors agree on the definition of "recurrent spontaneous abortion" (RSA), so the frequency of repeated pregnancy wastage is difficult to determine; from empirically derived data, it has been estimated to range between 0.4 and 0.8%. Because of the various etiologies of RSA, their association in determining an abortive event, it is difficult to evaluate their exact incidence. Moreover, their is no prospective study on this subject, so it is advisable to distinguish between the admitted causes, the likely factors, and the etiologies to be evaluated. In the first group, the congenital or acquired müllerian anomalies (especially the septate uterus), represent about 25% of the RSA, but a lot of problems concerning the physiopathology are still debated, even if the rate of pregnancies after surgery ranges around 50% in certain series. On the other hand, the genetic factors, identified especially with the banding technique, are undeniable: however, although the rate of chromosomal aberrations in the offspring (Monosomy X, Trisony 16, Triploidy) is very high (50 to 60% of spontaneous abortions in the first trimester of pregnancy), when couples with usual abortions are subjected to karyotypic analysis, genetic anomalies (especially translocations) are been noted in only 6.2% of the women and 2.6% of the men. In the second group, the infective factors (chlamydiae, toxoplasma and mycoplasma) are difficult to analyse since the serology is not sufficient without a real proof of an endometrial colonization. Among the endocrinological causes, the classical luteal phase deficiency remains a subject of controversy (estimated between 3 and 30%) not only for the establishment of the diagnosis, but also for the efficiency of progesterone

  6. The Ghostly Novae of Spirits: Candidates, Confirmations, and Classifications

    NASA Astrophysics Data System (ADS)

    Corgan, David William

    2015-08-01

    The SPIRITS (SPitzer InfraRed Intensive Transients Survey) project has surveyed 242 galaxies across multiple epochs for over a year, searching for gap transient and variable star activity. To date, a wealth of candidate objects has been discovered in the warm Spitzer data being used, with the current total at 1426 individual detections. The discovery, confirmation, follow-up, and comparison to prediction rates of these candidates is presented. Employing subjective detection methods, discussed herein, individual discovery to group confirmation rates were found to be less than 3.6%. Photometric confirmation with correlated team instruments left 53 sources of interest remaining for further study. These targets ranged across 30 different galaxies including IC2163, Messier 101, and NGC3198. Follow-up ground observations in the 1.2, 1.6, and 2.2 µm wavelengths with the legacy 2MASS instrument at MLOF (Mount Lemmon Observing Facility) are highlighted. The data reduction process which has evolved to improve detections by ~.6mag is also detailed. These results are supplemented by SPIRITS team input from a variety of world-class infrared facilities to produce overall nova candidate characteristics, which are included. In some cases this extends to light curves from confirmed and observed novae to depths of ~20mag, while in others it is restricted to limiting magnitudes of ~18 at sight of occurrence (the true “ghosts” of SPIRITS). Candidate novae have been separated into classes where data allows, including the possible discovery of a new variable type coined SMIRTS (Super Massive InfraRed TransientS), and probable members of the elusive Luminous Red Novae category. Finally, comparison of numerical survey results to nova prediction rates is undertaken and results presented. Where deviations from luminosity curve fittings occur, such as in the overly active M81 and IC0342 galaxies, possible causes are proposed.

  7. Johannes Hevelius, nova CK Vulpeculae (1670) and the "hibernation" model of cataclysmic variables.

    NASA Astrophysics Data System (ADS)

    Smak, J.

    The author reviews the basic properties of cataclysmic variables and the thermonuclear runaway (TNR) theory of the outbursts of novae, including the "hibernation" model of cataclysmic variables. The TNR theory, while remarkably successful in explaining a number of observational properties of novae, met also with some difficulties related to (1) excessive mass-transfer rates in old novae, and (2) conflicting estimates of their space density. Both are estimated from absolute magnitudes of novae as observed within decades before, or after, their outbursts. Nova CK Vulpeculae (1670), the oldest recorded nova, was observed in 1670 - 1672 by Hevelius, whose observations - together with those by Anthelme and Cassini - were sufficiently numerous and accurate to permit a modern reconstruction of the light curve and its classification as a very slow nova.

  8. Bone Marrow Stress Decreases Osteogenic Progenitors.

    PubMed

    Ng, Adeline H; Baht, Gurpreet S; Alman, Benjamin A; Grynpas, Marc D

    2015-11-01

    Age-related bone loss may be a result of declining levels of stem cells in the bone marrow. Using the Col2.3Δtk (DTK) transgenic mouse, osteoblast depletion was used as a source of marrow stress in order to investigate the effects of aging on osteogenic progenitors which reside in the marrow space. Five-month-old DTK mice were treated with one or two cycles of ganciclovir to conditionally ablate differentiated osteoblasts, whereas controls were saline-treated. Treatment cycles were two weeks in length followed by four weeks of recovery. All animals were sacrificed at 8 months of age; bone marrow stromal cells (BMSCs) were harvested for cell culture and whole bones were excised for bone quality assessment. Colony-forming unit (CFU) assays were conducted to investigate the osteogenic potential of BMSC in vitro, and RNA was extracted to assess the expression of osteoblastic genes. Bone quality assessments included bone histomorphometry, TRAP staining, microcomputed tomography, and biomechanical testing. Osteoblast depletion decreased CFU-F (fibroblast), CFU-ALP (alkaline phosphatase), and CFU-VK (von Kossa) counts and BMSC osteogenic capacity in cell culture. Ex vivo, there were no differences in bone mineral density of vertebrae or femurs between treatment groups. Histology showed a decrease in bone volume and bone connectivity with repeated osteoblast depletion; however, this was accompanied by an increase in bone formation rate. There were no notable differences in osteoclast parameters or observed bone marrow adiposity. We have developed a model that uses bone marrow stress to mimic age-related decrease in osteogenic progenitors. Our data suggest that the number of healthy BMSCs and their osteogenic potential decline with repeated osteoblast depletion. However, activity of the remaining osteoblasts increases to compensate for this loss in progenitor osteogenic potential.

  9. Bone Marrow Stress Decreases Osteogenic Progenitors.

    PubMed

    Ng, Adeline H; Baht, Gurpreet S; Alman, Benjamin A; Grynpas, Marc D

    2015-11-01

    Age-related bone loss may be a result of declining levels of stem cells in the bone marrow. Using the Col2.3Δtk (DTK) transgenic mouse, osteoblast depletion was used as a source of marrow stress in order to investigate the effects of aging on osteogenic progenitors which reside in the marrow space. Five-month-old DTK mice were treated with one or two cycles of ganciclovir to conditionally ablate differentiated osteoblasts, whereas controls were saline-treated. Treatment cycles were two weeks in length followed by four weeks of recovery. All animals were sacrificed at 8 months of age; bone marrow stromal cells (BMSCs) were harvested for cell culture and whole bones were excised for bone quality assessment. Colony-forming unit (CFU) assays were conducted to investigate the osteogenic potential of BMSC in vitro, and RNA was extracted to assess the expression of osteoblastic genes. Bone quality assessments included bone histomorphometry, TRAP staining, microcomputed tomography, and biomechanical testing. Osteoblast depletion decreased CFU-F (fibroblast), CFU-ALP (alkaline phosphatase), and CFU-VK (von Kossa) counts and BMSC osteogenic capacity in cell culture. Ex vivo, there were no differences in bone mineral density of vertebrae or femurs between treatment groups. Histology showed a decrease in bone volume and bone connectivity with repeated osteoblast depletion; however, this was accompanied by an increase in bone formation rate. There were no notable differences in osteoclast parameters or observed bone marrow adiposity. We have developed a model that uses bone marrow stress to mimic age-related decrease in osteogenic progenitors. Our data suggest that the number of healthy BMSCs and their osteogenic potential decline with repeated osteoblast depletion. However, activity of the remaining osteoblasts increases to compensate for this loss in progenitor osteogenic potential. PMID:26220824

  10. Adipose Tissue Residing Progenitors (Adipocyte Lineage Progenitors and Adipose Derived Stem Cells (ADSC)

    PubMed Central

    Berry, Ryan; Rodeheffer, Matthew S.; Rosen, Clifford J.; Horowitz, Mark C.

    2015-01-01

    The formation of brown, white and beige adipocytes have been a subject of intense scientific interest in recent years due to the growing obesity epidemic in the United States and around the world. This interest has led to the identification and characterization of specific tissue resident progenitor cells that give rise to each adipocyte population in vivo. However, much still remains to be discovered about each progenitor population in terms of their “niche” within each tissue and how they are regulated at the cellular and molecular level during healthy and diseased states. While our knowledge of brown, white and beige adipose tissue is rapidly increasing, little is still known about marrow adipose tissue and its progenitor despite recent studies demonstrating possible roles for marrow adipose tissue in regulating the hematopoietic space and systemic metabolism at large. This chapter focuses on our current knowledge of brown, white, beige and marrow adipose tissue with a specific focus on the formation of each tissue from tissue resident progenitor cells. PMID:26526875

  11. Discovery of an Apparent Nova in M81 and H-alpha Confirmation of Three M81 Nova Candidates

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Tudor, V.

    2014-06-01

    We report the discovery of an apparent nova in M81 on a co-added 2000-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.6" seeing on 2014 Jun. ...

  12. Progenitor endothelial cell involvement in Alzheimer's disease

    SciTech Connect

    Budinger, Thomas F.

    2003-05-01

    There is compelling evidence that endothelial cells of the brain and periphery are dysfunctional in Alzheimer's Disease. There is evidence for a fundamental defect in, or abnormal aging of, endothelial progenitor cells in atherosclerosis. The possibility that endothelial cell defects are a primary cause for Alzheimer's Disease or other dementias can be researched by molecular and cell biology studies as well as cell trafficking studies using recently demonstrated molecular imaging methods. The evidence for abnormal endothelial function and the methods to explore this hypothesis are presented.

  13. Enhancing endothelial progenitor cell for clinical use

    PubMed Central

    Ye, Lei; Poh, Kian-Keong

    2015-01-01

    Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases. PMID:26240678

  14. Enhancing endothelial progenitor cell for clinical use.

    PubMed

    Ye, Lei; Poh, Kian-Keong

    2015-07-26

    Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

  15. The recurrence rate of stones following ESWL.

    PubMed

    Köhrmann, K U; Rassweiler, J; Alken, P

    1993-01-01

    With extracorporeal shockwave lithotripsy (ESWL) stone fragmentation and the potential creation of residual stones has become an integral part of the treatment strategy. Therefore true recurrence, regrowth and pseudo-recurrence determine the rate of new stone formation. In unselected series the overall recurrence rate after ESWL varies between 6% after 1 year and 20% after 4 years. The comparison between the recurrence rate after ESWL and the natural recurrence rate reveals that the results of ESWL are better than expected. Lithotripsy has no special effect on true stone recurrence, and even pseudo-recurrence is of minor clinical significance.

  16. The Type Ia Supernovae Progenitor Problem: Searching for Progenitors in the Milky Way

    NASA Astrophysics Data System (ADS)

    Birchall, Alexander; Di Stefano, R.; Primini, F.; Scalzo, R.

    2013-01-01

    One of the most active areas of current astrophysical research is the search for the progenitors of Type Ia supernovae. Understanding the nature(s) of the progenitors is crucial if we are to use these supernovae to conduct high-precision measurements of the history of cosmic expansion, because in order to confirm them as standardizable candles we need to understand the mechanism by which they are produced. Type Ia supernovae occur when carbon/oxygen white dwarfs explode, having gained mass either by accretion from a companion or by merging with another white dwarf. The white dwarfs in all Type Ia progenitors must go through a stage of high-rate accretion and possibly of nuclear burning. They should then be detectable as bright objects, with luminosities as high as a few times 1038 erg s-1. Furthermore, whatever the correct model(s), more than 1000 bright progenitors (and other systems that may be equally bright but in which the white dwarf does not reach the critical mass) are expected in the Milky Way. We are conducting a comprehensive search through archived data to identify unusual bright sources that may correspond to white dwarfs accreting at high rates. A significant fraction of the progenitors may appear as x-ray sources that are either supersoft or quasisoft some of the time. We have therefore searched the ROSAT, Chandra, and XMM databases to identify all such soft sources in the Milky Way that are detectable from Earth. We report on our results and their implications.

  17. THE SUPERSOFT X-RAY PHASE OF NOVA RS OPHIUCHI 2006

    SciTech Connect

    Osborne, J. P.; Page, K. L.; Beardmore, A. P.; Goad, M. R.; Bode, M. F.; O'Brien, T. J.; Starrfield, S.; Rauch, T.; Ness, J.-U.; Krautter, J.; Schwarz, G.; Burrows, D. N.; Gehrels, N.; Drake, J. J.; Evans, A.; Eyres, S. P. S.

    2011-02-01

    Swift X-ray observations of the {approx}60 day supersoft phase of the recurrent nova RS Ophiuchi (RS Oph) 2006 show the progress of nuclear burning on the white dwarf (WD) in exquisite detail. First seen 26 days after the optical outburst, this phase started with extreme variability likely due to variable absorption, although intrinsic WD variations are not excluded. About 32 days later, a steady decline in count rate set in. NLTE model atmosphere spectral fits during the supersoft phase show that the effective temperature of the WD increases from {approx}65 eV to {approx}90 eV during the extreme variability phase, falling slowly after about day 60 and more rapidly after day 80. The bolometric luminosity is seen to be approximately constant and close to Eddington from day 45 up to day 60, the subsequent decline possibly signaling the end of extensive nuclear burning. Before the decline, a multiply-periodic {approx}35 s modulation of the soft X-rays was present and may be the signature of a nuclear fusion driven instability. Our measurements are consistent with a WD mass near the Chandrasekhar limit; combined with a deduced accumulation of mass transferred from its binary companion, this leads us to suggest that RS Oph is a strong candidate for a future supernova explosion. The main uncertainty now is whether the WD is the CO type necessary for a Type Ia supernova. This may be confirmed by detailed abundance analyses of spectroscopic data from the outbursts.

  18. Very high-energy γ-ray observations of novae and dwarf novae with the MAGIC telescopes

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; 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.; de Oña Wilhelmi, E.; Delgado Mendez, C.; Di Pierro, F.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Godinović, N.; González Muñoz, A.; 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.; Nievas Rosillo, M.; 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.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; 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.

    2015-10-01

    Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV γ-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 γ-ray spectrum at TeV energies. Aims: We aim to explore the very high-energy domain to search for γ-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; optical and subsequent GeV γ-ray detections triggered the MAGIC observations. 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 contemporaneous Fermi-LAT data of the sources. The TeV and GeV observations are compared in order to evaluate the acceleration parameters for leptons and hadrons. Results: No significant TeV emission was found from the studied sources. We computed upper limits on the spectrum and night-by-night flux. The combined GeV and TeV observations of V339 Del limit the ratio of proton to electron luminosities to Lp ≲ 0.15 Le. Appendix A is available in electronic form at http://www.aanda.org

  19. Treatment of recurrent vulvovaginal candidiasis.

    PubMed

    Ringdahl, E N

    2000-06-01

    Vulvovaginal candidiasis is considered recurrent when at least four specific episodes occur in one year or at least three episodes unrelated to antibiotic therapy occur within one year. Although greater than 50 percent of women more than 25 years of age develop vulvovaginal candidiasis at some time, fewer than 5 percent of these women experience recurrences. Clinical evaluation of recurrent episodes is essential. Patients who self-diagnose may miss other causes or concurrent infections. Known etiologies of recurrent vulvovaginal candidiasis include treatment-resistant Candida species other than Candida albicans, frequent antibiotic therapy, contraceptive use, compromise of the immune system, sexual activity and hyperglycemia. If microscopic examination of vaginal secretions in a potassium hydroxide preparation is negative but clinical suspicion is high, fungal cultures should be obtained. After the acute episode has been treated, subsequent prophylaxis (maintenance therapy) is important. Because many patients experience recurrences once prophylaxis is discontinued, long-term therapy may be warranted. Patients are more likely to comply when antifungal therapy is administered orally, but oral treatment carries a greater potential for systemic toxicity and drug interactions.

  20. Neutrino emission from nearby supernova progenitors

    NASA Astrophysics Data System (ADS)

    Yoshida, Takashi; Takahashi, Koh; Umeda, Hideyuki

    2016-05-01

    Neutrinos have an important role for energy loss process during advanced evolution of massive stars. Although the luminosity and average energy of neutrinos during the Si burning are much smaller than those of supernova neutrinos, these neutrinos are expected to be detected by the liquid scintillation neutrino detector KamLAND if a supernova explosion occurs at the distance of ~100 parsec. We investigate the neutrino emission from massive stars during advanced evolution. We calculate the evolution of the energy spectra of neutrinos produced through electron-positron pair-annihilation in the supernova progenitors with the initial mass of 12, 15, and 20 M ⊙ during the Si burning and core-collapse stages. The neutrino emission rate increases from ~ 1050 s-1 to ~ 1052 s-1. The average energy of electron-antineutrinos is about 1.25 MeV during the Si burning and gradually increases until the core-collapse. For one week before the supernova explosion, the KamLAND detector is expected to observe 12-24 and 6-13 v¯e events in the normal and inverted mass hierarchies, respectively, if a supernova explosion of a 12-20 M ⊙ star occurs at the distance of 200 parsec, corresponding to the distance to Betelgeuse. Observations of neutrinos from SN progenitors have a possibility to constrain the core structure and the evolution just before the core collapse of massive stars.

  1. Endothelial progenitor cells in diabetic foot syndrome.

    PubMed

    Drela, Ewelina; Stankowska, Katarzyna; Kulwas, Arleta; Rość, Danuta

    2012-01-01

    In the late 20th century endothelial progenitor cells (EPCs) were discovered and identified as cells capable of differentiating into endothelial cells. Antigens characteristic of endothelial cells and hematopoietic cells are located on their surface. EPCs can proliferate, adhere, migrate and have the specific ability to form vascular structure, and they have a wide range of roles: They participate in maintaining hemostasis, and play an important part in the processes of vasculogenesis and angiogenesis. They are sources of angiogenic factors, especially vascular endothelial growth factor (VEGF). EPCs exist in bone marrow, from which they are recruited into circulation in response to specific stimuli. Tissue ischemia is thought to be the strongest inductor of EPC mobilization. Local ischemia accompanies many pathological states, including diabetic foot syndrome (DFS). Impaired angiogenesis--in which EPCs participate--is typical of DFS. An analysis of the available literature indicates that in diabetic patients the number of EPCs declines and their functioning is impaired. Endothelial progenitor cells are crucial to vasculogenesis and angiogenesis during ischemic neovascularization. The pathomechanisms underlying impaired angiogenesis in patients with DFS is complicated, but the discovery of EPCs has shed new light on the pathogenesis of many diseases, including diabetes foot syndrome.

  2. Progenitor Cell Dysfunctions Underlie Some Diabetic Complications

    PubMed Central

    Rodrigues, Melanie; Wong, Victor W.; Rennert, Robert C.; Davis, Christopher R.; Longaker, Michael T.; Gurtner, Geoffrey C.

    2016-01-01

    Stem cells and progenitor cells are integral to tissue homeostasis and repair. They contribute to health through their ability to self-renew and commit to specialized effector cells. Recently, defects in a variety of progenitor cell populations have been described in both preclinical and human diabetes. These deficits affect multiple aspects of stem cell biology, including quiescence, renewal, and differentiation, as well as homing, cytokine production, and neovascularization, through mechanisms that are still unclear. More important, stem cell aberrations resulting from diabetes have direct implications on tissue function and seem to persist even after return to normoglycemia. Understanding how diabetes alters stem cell signaling and homeostasis is critical for understanding the complex pathophysiology of many diabetic complications. Moreover, the success of cell-based therapies will depend on a more comprehensive understanding of these deficiencies. This review has three goals: to analyze stem cell pathways dysregulated during diabetes, to highlight the effects of hyperglycemic memory on stem cells, and to define ways of using stem cell therapy to overcome diabetic complications. PMID:26079815

  3. The progenitors of supernovae Type Ia

    NASA Astrophysics Data System (ADS)

    Toonen, Silvia

    2014-09-01

    Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. SNeIa are generally thought to be thermonuclear explosions of carbon/oxygen (CO) white dwarfs (WDs). The canonical scenarios involve white dwarfs reaching the Chandrasekhar mass, either by accretion from a non-degenerate companion (single-degenerate channel, SD) or by a merger of two CO WDs (double-degenerate channel, DD). The study of SNeIa progenitors is a very active field of research for binary population synthesis (BPS) studies. The strength of the BPS approach is to study the effect of uncertainties in binary evolution on the macroscopic properties of a binary population, in order to constrain binary evolutionary processes. I will discuss the expected SNeIa rate from the BPS approach and the uncertainties in their progenitor evolution, and compare with current observations. I will also discuss the results of the POPCORN project in which four BPS codes were compared to better understand the differences in the predicted SNeIa rate of the SD channel. The goal of this project is to investigate whether differences in the simulated populations are due to numerical effects or whether they can be explained by differences in the input physics. I will show which assumptions in BPS codes affect the results most and hence should be studied in more detail.

  4. Red supergiants as type II supernova progenitors

    NASA Astrophysics Data System (ADS)

    Negueruela, Ignacio; Dorda, Ricardo; González-Fernández, Carlos; Marco, Amparo

    2015-08-01

    Recent searches for supernova IIp progenitors in external galaxies have led to the identification of red objects with magnitudes and colours indicative of red supergiants, in most cases implying quite low luminosities and hence masses well below 10Msol. Stellar models, on the other hand, do not predict explosions from objects below 9 Msol. What does our knowledge of local red supergiants tells us about the expected properties of such objects?We have carried out a comprehensive spectroscopic and photometric study of a sample of hundreds of red supergiants in the Milky Way and both Magellanic Clouds. We have explored correlations between different parameters and the position of stars in the HR diagrams of open clusters. At solar metallicty, there is strong evidence for a phase of very heavy mass loss at the end of the red supergiant phase, but the existence of such a phase is still not confirmed at SMC metallicities. Objects of ~ 7Msol, on the other hand, become very dusty in the SMC, and appear as very luminous Miras.Among Milky Way clusters, we find a surprising lack of objects readily identifiable as the expected 7 to 10 Msol red supergiants or AGB stars. We are carrying out an open cluster survey aimed at filling this region of the HR diagram with reliable data. Finally, we will discuss the implications of all this findings for the expected properties of supernova progenitors, as it looks unlikely that typical red supergiants may explode without undergoing further evolution.

  5. Mechanisms of cardiogenesis in cardiovascular progenitor cells.

    PubMed

    Taubenschmid, Jasmin; Weitzer, Georg

    2012-01-01

    Self-renewing cells of the vertebrate heart have become a major subject of interest in the past decade. However, many researchers had a hard time to argue against the orthodox textbook view that defines the heart as a postmitotic organ. Once the scientific community agreed on the existence of self-renewing cells in the vertebrate heart, their origin was again put on trial when transdifferentiation, dedifferentiation, and reprogramming could no longer be excluded as potential sources of self-renewal in the adult organ. Additionally, the presence of self-renewing pluripotent cells in the peripheral blood challenges the concept of tissue-specific stem and progenitor cells. Leaving these unsolved problems aside, it seems very desirable to learn about the basic biology of this unique cell type. Thus, we shall here paint a picture of cardiovascular progenitor cells including the current knowledge about their origin, basic nature, and the molecular mechanisms guiding proliferation and differentiation into somatic cells of the heart. PMID:22251563

  6. Radioprotection of hematopoietic progenitors by low dose amifostine prophylaxis

    PubMed Central

    Seed, Thomas M.; Inal, Cynthia E.

    2014-01-01

    Purpose Amifostine is a highly efficacious cytoprotectant when administered in vivo at high doses. However, at elevated doses, drug toxicity manifests for general, non-clinical radioprotective purposes. Various strategies have been developed to avoid toxic side-effects: The simplest is reducing the dose. In terms of protecting hematopoietic tissues, where does this effective, non-toxic minimum dose lie? Material and methods C3H/HEN mice were administered varying doses of amifostine (25–100 mg/kg) 30 min prior to cobalt-60 irradiation and euthanized between 4–14 days for blood and bone marrow collection and analyses. Results Under steady-state, amifostine had little effect on bipotential and multi-potential marrow progenitors but marginally suppressed a more primitive, lineage negative progenitor subpopulation. In irradiated animals, prophylactic drug doses greater than 50 mg/kg resulted in significant regeneration of bipotential progenitors, moderate regeneration of multipotential progenitors, but no significant and consistent regeneration of more primitive progenitors. The low amifostine dose (25 mg/kg) failed to elicit consistent and positive, radioprotective actions on any of the progenitor subtypes. Conclusions Radioprotective doses for amifostine appear to lie between 25 and 50 mg/kg. Mature, lineage-restricted progenitors appear to be more responsive to the protective effects of low doses of amifostine than the more primitive, multipotential progenitors. PMID:24597748

  7. Mobilization of hematopoietic progenitor cells in patients with liver cirrhosis

    PubMed Central

    Gehling, Ursula M; Willems, Marc; Schlagner, Kathleen; Benndorf, Ralf A; Dandri, Maura; Petersen, Jörg; Sterneck, Martina; Pollok, Joerg-Matthias; Hossfeld, Dieter K; Rogiers, Xavier

    2010-01-01

    AIM: To test the hypothesis that liver cirrhosis is associated with mobilization of hematopoietic progenitor cells. METHODS: Peripheral blood samples from 72 patients with liver cirrhosis of varying etiology were analyzed by flow cytometry. Identified progenitor cell subsets were immunoselected and used for functional assays in vitro. Plasma levels of stromal cell-derived factor-1 (SDF-1) were measured using an enzyme linked immunosorbent assay. RESULTS: Progenitor cells with a CD133+/CD45+/CD14+ phenotype were observed in 61% of the patients. Between 1% and 26% of the peripheral blood mononuclear cells (MNCs) displayed this phenotype. Furthermore, a distinct population of c-kit+ progenitor cells (between 1% and 38 % of the MNCs) could be detected in 91% of the patients. Additionally, 18% of the patients showed a population of progenitor cells (between 1% and 68% of the MNCs) that was characterized by expression of breast cancer resistance protein-1. Further phenotypic analysis disclosed that the circulating precursors expressed CXC chemokine receptor 4, the receptor for SDF-1. In line with this finding, elevated plasma levels of SDF-1 were present in all patients and were found to correlate with the number of mobilized CD133+ progenitor cells. CONCLUSION: These data indicate that in humans, liver cirrhosis leads to recruitment of various populations of hematopoietic progenitor cells that display markers of intrahepatic progenitor cells. PMID:20066741

  8. Progenitor cells in arteriosclerosis: good or bad guys?

    PubMed

    Campagnolo, Paola; Wong, Mei Mei; Xu, Qingbo

    2011-08-15

    Accumulating evidence indicates that the mobilization and recruitment of circulating or tissue-resident progenitor cells that give rise to endothelial cells (ECs) and smooth muscle cells (SMCs) can participate in atherosclerosis, neointima hyperplasia after arterial injury, and transplant arteriosclerosis. It is believed that endothelial progenitor cells do exist and can repair and rejuvenate the arteries under physiologic conditions; however, they may also contribute to lesion formation by influencing plaque stability in advanced atherosclerotic plaque under specific pathologic conditions. At the same time, smooth muscle progenitors, despite their capacity to expedite lesion formation during restenosis, may serve to promote atherosclerotic plaque stabilization by producing extracellular matrix proteins. This profound evidence provides support to the hypothesis that both endothelial and smooth muscle progenitors may act as a double-edged sword in the pathogenesis of arteriosclerosis. Therefore, the understanding of the regulatory networks that control endothelial and smooth muscle progenitor differentiation is undoubtedly fundamental both for basic research and for improving current therapeutic avenues for atherosclerosis. We update the progress in progenitor cell study related to the development of arteriosclerosis, focusing specifically on the role of progenitor cells in lesion formation and discuss the controversial issues that regard the origins, frequency, and impact of the progenitors in the disease.

  9. A multiwavelength study of the remnant of nova GK Persei

    NASA Astrophysics Data System (ADS)

    Anupama, G. C.; Kantharia, N. G.

    2005-05-01

    We present new observations of the nebular remnant of the old nova GK Persei 1901 in the optical using the Himalayan Chandra Telescope (HCT) and at low radio frequencies using the Giant Metrewave Radio Telescope (GMRT). The dimensions of the shell in the optical emission lines of [NII], [OIII] and [OII] are 108× 94 arcsec2, 104× 94 arcsec2 and 99× 87 arcsec2, respectively. The evolution of the nova remnant indicates shock interaction with the ambient medium, especially in the southwest quadrant. Application of a simple model for the shock and its evolution to determine the time dependence of the radius of the shell in the southwest quadrant indicates that the shell is now expanding into an ambient medium that has a density of 0.12 cm-3, compared to the density of the ambient medium of 0.8 cm-3 ahead of the shock in 1987. There are indications of a recent interaction of the nova remnant with the ambient medium in the northeast quadrant. There is a distinct flattening of the shell, as well as an increase in the number and brightness of the knots in the region. The brightest optical knots in this region are also detected in the radio images. The nova remnant of GK Per is detected at all the observed radio frequencies and is of a similar extent to the optical remnant. Putting together our radio observations with VLA archival data on GK Per from 1997, we obtain three interesting results: 1. the spectrum above 1.4 GHz follows a power law with an index -0.7 (S∝ να) and below 1.4 GHz follows a power law with an index ˜ -0.85. This could be due to the presence of at least two populations of electrons dominating the global emission at different frequencies; 2. we record an annual secular decrease of 2.1% in the flux density of the nova remnant at 1.4 and 4.9 GHz between 1984 and 1997 which has left the spectral index unchanged at -0.7. No such decrease is observed in the flux densities below 1 GHz; 3. we record an increase in the flux density at 0.33 GHz compared to

  10. [Pediatric clubfoot : Treatment of recurrence].

    PubMed

    Radler, C; Mindler, G T

    2016-10-01

    Over the last 10 years the Ponseti method has become established as the gold standard for initial treatment of clubfeet nearly worldwide. Nevertheless, there are considerable fluctuations regarding the authenticity and quality in the application of the Ponseti method. Especially the efforts to ensure and promote compliance with the foot abduction brace and subsequently the recurrence rate show great variation. As a result, we are still faced with a significant number of recurrent or residual clubfeet. In recent years it has been shown in high-volume clinics that even these can almost always be successfully treated with recasting and with minor interventions, such as anterior tibial tendon transfer and lengthening of the Achilles tendon. More invasive surgical procedures are only very rarely indicated and are reserved for severe recurrence in previously surgically treated and secondary clubfeet. PMID:27577568

  11. [The recurrent multifocal pleomorphic adenoma].

    PubMed

    Vigili, M G; Sciarretta, F; Marzetti, A; Marzetti, F

    1993-01-01

    Pleomorphic adenoma (P.A.), the most common tumor of the salivary gland, demonstrates a peculiar clinicopathological behaviour for numerous reasons: the high recurrence rate following primary surgery (up to 50%), the appearance of malignancy (2-9%), the reported number of distant metastases histologically identical to the primary P.A. From among 71 cases of benign parotid tumors treated from Nov. 89 to Nov. 92 in the ENT Department of "Regina Elena", the National Cancer Institute in Rome, six particular cases showed multiple force of P.A. recurring after primary surgery performed from 3 to 32 years previously and are object of discussion in this study. All of these six cases had multiple recurrences, usually manifest as nodular clusters in the parotid area, while in three cases appeared as well a recurrence in the soft tissue of the neck, far removed from the parotid space, with no involvement of neck nodes as was revealed through histological examination following neck dissection. A hypothetical mechanism of diffusion is discussed. The Authors agree with the opinion which holds the surgeon's inability to successfully eradicate primary tumors responsible for the high frequency of recurrences. The surgical technique of "enucleation" is, in fact, inadequate in P.A. excision owing the high risk of mishandling or rupturing the tumor capsule with a consequent seeding of the tumor onto the surgical bed. Lateral lobectomy, with identification of the facial nerve, or total conservative parotidectomy (for deep lobe adenoma) are correct techniques in treating primary P.A.. The Authors also discuss management of recurrent P.A. in relation to facial nerve involvement. Preservation of the seventh nerve with eventual post-operative radiation should be considered an alternative to nerve sacrifice in selected cases of recurrent pleomorphic adenoma.

  12. NON-EQUIPARTITION OF ENERGY, MASSES OF NOVA EJECTA, AND TYPE Ia SUPERNOVAE

    SciTech Connect

    Shara, Michael M.; Yaron, Ofer; Prialnik, Dina; Kovetz, Attay

    2010-04-01

    The total masses ejected during classical nova (CN) eruptions are needed to answer two questions with broad astrophysical implications: can accreting white dwarfs be 'pushed over' the Chandrasekhar mass limit to yield type Ia supernovae? Are ultra-luminous red variables a new kind of astrophysical phenomenon, or merely extreme classical novae? We review the methods used to determine nova ejecta masses. Except for the unique case of BT Mon (nova 1939), all nova ejecta mass determinations depend on untested assumptions and multi-parameter modeling. The remarkably simple assumption of equipartition between kinetic and radiated energy (E {sub kin} and E {sub rad}, respectively) in nova ejecta has been invoked as a way around this conundrum for the ultra-luminous red variable in M31. The deduced mass is far larger than that produced by any CN model. Our nova eruption simulations show that radiation and kinetic energy in nova ejecta are very far from being in energy equipartition, with variations of 4 orders of magnitude in the ratio E {sub kin}/E {sub rad} being commonplace. The assumption of equipartition must not be used to deduce nova ejecta masses; any such 'determinations' can be overestimates by a factor of up to 10,000. We data-mined our extensive series of nova simulations to search for correlations that could yield nova ejecta masses. Remarkably, the mass ejected during a nova eruption is dependent only on (and is directly proportional to) E {sub rad}. If we measure the distance to an erupting nova and its bolometric light curve, then E {sub rad} and hence the mass ejected can be directly measured.

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

    SciTech Connect

    Schwarz, Greg J.; Ness, Jan-Uwe; Osborne, J. P.; Page, K. L.; Evans, P. A.; Beardmore, A. P.; Walter, Frederick M.; Andrew Helton, L.; Woodward, Charles E.; Bode, Mike; Starrfield, Sumner; Drake, Jeremy J.

    2011-12-01

    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 A) 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 t{sub 2} 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.

  14. Recurrent abdominal pain during childhood.

    PubMed Central

    Scott, R. B.

    1994-01-01

    Recurrent abdominal pain is a common presenting complaint among children. A thorough history and physical examination and limited laboratory investigation should enable a physician to make a positive diagnosis of "functional" recurrent abdominal pain in 90% to 95% of cases; an organic cause is identified in only 5% to 10%. The care and thoroughness of the history and physical examination establish the physician's credibility; explaining the clinical basis for the diagnosis and educating the child and parents on what is known about the condition reassures the parents. PMID:8199511

  15. Lapatinib in Treating Young Patients With Recurrent or Refractory Central Nervous System Tumors

    ClinicalTrials.gov

    2014-05-07

    Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Ependymoma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliosarcoma; Recurrent Childhood Medulloblastoma; Recurrent Childhood Oligodendroglioma

  16. Evolution of the post-nova GQ MUS (Nova MUSCAE 1983). II. Stellar atmospheres, coronal lines, and turnoff.

    NASA Astrophysics Data System (ADS)

    Morisset, C.; Pequignot, D.

    1996-09-01

    Photoionization models for the shell ejected by Nova Muscae 1983 are obtained for the period 1984-1992, considering post-nova atmosphere continua computed by MacDonald & Vennes (1991). A fit to their grid of models is proposed in an appendix. All features of the model shell obtained by Morisset & Pequignot assuming a blackbody primary source are preserved. However the effective temperature T_*_ derived for the source is about 15% lower. Reliable collision strengths for coronal lines are needed before the late evolution of the post-nova can be accurately determined. An extensive exploration of possible photoionization-model solutions indicates that (1) a suitable effective collision strength {OMEGA}_X_ for [Fe X] 637.5nm at 2x10^4^K is 3 to 5 times the pioneering result of Blaha (1969) and less than one half recent elaborate values, which are therefore strongly suspected to be overestimated, (2) the collision strength for [S VIII] 991.1 is moderately larger than according to Blaha, (3) the decline of the bolometric luminosity L_*_ amounts to a factor ~2 at the time of soft X-ray detection by ROSAT (day 3330), which may therefore nearly coincide with nuclear burning turnoff and maximum T_*_, and (4) depending on the collision strength {OMEGA}_XI_ for [Fe XI] 789.2nm, the maximum T_*_ is either of the order of 5x10^5^K ({OMEGA}_XI_ close to Blaha's result) or smaller than 4x10^5^K (large {OMEGA}_XI_). A way out of the conflict between theoretical and astrophysical determinations of {OMEGA}_X_ may be managed in the framework of present models if {OMEGA}_XI_ happens to be very large. Source parameters derived from nova shell models are relatively insensitive to details of stellar atmosphere models and may help to enhance the value of soft X-ray observations. Properties of GQ Mus disclosed by photoionization model analysis are shown to constitute a challenge to current understanding of novae and post-novae.

  17. Three-dimensional simulations of Nova capsule implosion experiments

    SciTech Connect

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-11-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.

  18. VERITAS Observations of the Nova in V407 Cygni

    NASA Astrophysics Data System (ADS)

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Collins-Hughes, E.; Connolly, M. P.; Cui, W.; Decerprit, G.; Dickherber, R.; Duke, C.; Dumm, J.; Dwarkadas, V. V.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Godambe, S.; Griffin, S.; Grube, J.; Gyuk, G.; Hanna, D.; Holder, J.; Huan, H.; Hughes, G.; Humensky, T. B.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Lee, K.; Maier, G.; Majumdar, P.; McArthur, S.; McCann, A.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nuñez, P. D.; Ong, R. A.; Orr, M.; Otte, A. N.; Pandel, D.; Park, N.; Perkins, J. S.; Pohl, M.; Prokoph, H.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Ruppel, J.; Saxon, D. B.; Schroedter, M.; Sembroski, G. H.; Skole, C.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tešić, G.; Theiling, M.; Thibadeau, S.; Tsurusaki, K.; Tyler, J.; Varlotta, A.; Vincent, S.; Vivier, M.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Welsing, R.; Williams, D. A.; Zitzer, B.

    2012-07-01

    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 × 10-12 erg cm-2 s-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.

  19. From RoboNova to HUBO: Platforms for Robot Dance

    NASA Astrophysics Data System (ADS)

    Grunberg, David; Ellenberg, Robert; Kim, Youngmoo E.; Oh, Paul Y.

    A robot with the ability to dance in response to music could lead to novel and interesting interactions with humans. For example, such a robot could be used to augment live performances alongside human dancers. This paper describes a system enabling humanoid robots to move in synchrony with music. A small robot, the Hitec RoboNova, was initially used to develop smooth sequences of complex gestures used in human dance. The system uses a real-time beat prediction algorithm so that the robot’s movements are synchronized with the audio. Finally, we implemented the overall system on a much larger robot, HUBO, to establish the validity of the smaller RoboNova as a useful prototyping platform.

  20. Life after eruption - IV. Spectroscopy of 13 old novae

    NASA Astrophysics Data System (ADS)

    Tappert, C.; Vogt, N.; Della Valle, M.; Schmidtobreick, L.; Ederoclite, A.

    2014-07-01

    We present data on 13 post-nova systems. This includes the recovery via UBVR photometry of the five post-novae X Cir, V2104 Oph, V363 Sgr, V928 Sgr and V1274 Sgr and their spectroscopic confirmation. We provide accurate coordinates and finding charts for those objects. Additional first-time or improved spectroscopic data are presented for V356 Aql, V500 Aql, V604 Aql, V1370 Aql, MT Cen, V693 CrA, V697 Sco and MU Ser. Investigating the behaviour of a few easily accessible parameters yields (limited) information on the accretion state and the system inclination. We predict that X Cir and V697 Sco are likely to reveal their orbital period via time series photometry and that long-term photometric monitoring of V356 Aql, V500 Aql, V1370 Aql and X Cir has a good chance of discovering outburst-like behaviour in these systems.