Nova Research Articles

Traffic mammals attraction of the highway MT-358

The main ecological impacts caused by roads are: changes in behavior; stress and / or removal of native species; modification in the food chain; fragmentation and alteration of habitats by edge effect; population isolation and loss of individuals due to vehicle collision. This work was carried out on the highway MT-358, which connects the city of Nova Olimpia to the State University of Mato Grosso campus of Tangara da Serra, with approximately 40 km of route. The records of the trampled animals were carried out between December 2016 and December 2017. A total of 21 monthly samplings were recorded during the study period. Thirty-eight mammals were recorded on the MT-358 highway during the study period, totaling 13 species of mammals distributed in 08 families. The most abundant species were Tamandua tetradactyla (23.7%), Euphractus sexcinctus (15.8%) and Cerdocyon thous (15.8%). These three most abundant species account for 55.3% of occurrences. Therefore, we suggest that road management institutions use methods that will help ensure adequate migration to the fauna and reduce the risk of impact of running over fauna on already paved roads.

Redefining 'Community': The Elusive Legacy of the Dramatists' Co-op of Nova Scotia

By many indications, playwriting in the Canadian Maritime provinces (Nova Scotia, New Brunswick, and Prince Edward Island) has never been more accomplished, diverse, and energetic. At the same time, however, many dramatists in this region experience a distinct and, for some, defining sense of isolation and disconnection from the rest of the country, particularly in terms of production opportunities beyond the East Coast. Aware of the limitations of local production, however enthusiastic the support of regional theatre companies and groups, a significant number of Maritimes playwrights lament the absence of vehicles—such as publication with national distribution—that may lead to increased profile for Maritimes drama within this country and internationally. At this juncture, it is particularly intriguing to consider the precedent of the Dramatists' Co-op of Nova Scotia. A boisterous offspring of the Nova Scotia Writers Federation, the Co-op took upon itself the challenge to foster, promote, distribute, and generally champion Nova Scotian and, ultimately, Atlantic Canadian (including Newfoundland) drama for two decades following its inception in 1976. A fundamental difference between the dominant (although not exclusive) philosophy of Co-op members and their contemporary counterparts, however, is in the definition of the concept of ‘community.' For, unlike the distinctly national and international interests regularly expressed in the current context, the Co-op placed a significant (although, again, not exclusive) emphasis on the establishment of a local community of theatre artists and, even more fundamental, of local theatre audiences. The contrast, while neither simple nor absolute, provides a productive point of entry into the complex reality of contemporary Maritimes dramatic practice. Plusieurs signes nous montrent que l'ecriture theâtrale des provinces maritimes canadiennes (Nouvelle Ecosse, Nouveau Brunswick et l'Ile du Prince Edouard), n'a jamais ete aussi accomplie, variee et vivante. Mais, en meme temps, beaucoup d'auteurs dramatiques de cette region se sentent separes, sinon isoles, du reste du pays concernant la production de leurs pieces audela de la cote est. Conscients des restrictions d'une production limitee aux provinces maritimes, malgre l'aide enthousiaste des compagnies et des groupes regionnaux theâtraux, plusieurs auteurs dramatiques se lamentent du manque de publicite et de l'absence de diffusion nationale qui pourrait faire reconnaitre leurs pieces dramatiques a l'echelle nationale et internationale. A ce moment, cela nous intrigue de penser au precedent de la "Dramatists' Co-op of Nova Scotia." Progeniture tapageuse de la "Nova Scotia Writers Federation," la Cooperative a pris en charge le defi d'encourager, de promouvoir et de distribuer les pieces de Nouvelle Ecosse, aussi bien que celles de l'est du Canada (y compris Terre Neuve), pendant les vingt annees qui suivirent sa conception en 1976. Mais il y a entre les membres de la Cooperative et ses contemporains une distinction philosophique dans la definition du concept ‘communaute' qui va a l'encontre du terme dans les interets nationaux et internationaux. La Cooperative a donc insiste sur l'importance de la collectivite, de la localite de la communaute artistique, et encore plus, sur son public potentiel. Le contraste, ni simple ni absolu, permet un point d'insertion dans l'exercice complique du theâtre maritime canadien d'aujourd'hui.

Multiwavelength Modeling of the SED of Nova V339 Del: Stopping the Wind and Long-lasting Super-Eddington Luminosity with Dust Emission

Abstract During the classical nova outburst, the radiation generated by the nuclear burning of hydrogen in the surface layer of a white dwarf (WD) is reprocessed by the outer material into different forms at softer energies, whose distribution in the spectrum depends on the nova age. Using the method of multiwavelength modeling the spectral energy distribution (SED), we determined physical parameters of the stellar, nebular, and dust component of radiation isolated from the spectrum of the classical nova V339 Del from day 35 to day 636 after its explosion. The transition from the iron-curtain phase to the supersoft source phase (days 35–72), when the optical brightness dropped by 3–4 mag, the absorbing column density fell by its circumstellar component from ∼1 × 1023 to ∼1 × 1021 cm−2, and the emission measure decreased from ∼2 × 1062 to ∼8.5 × 1060 cm−3, was caused by stopping down the mass loss from the WD. The day 35 model SED indicated an oblate shape of the WD pseudophotosphere and the presence of the dust located in a slow equatorially concentrated outflow. The dust emission peaked around day 59. Its coexistence with the strong supersoft X-ray source in the day 100 model SED constrained the presence of the disk-like outflow, where the dust can spend a long time. Both the SED models revealed a super-Eddington luminosity of the burning WD at a level of (1–2) × 1039 (d/4.5 kpc)2 erg s−1, lasting from ∼day 2 to at least day 100.

Periods of water deficit after sowing cowpea

The study aimed to evaluate the germination and initial growth of semi-erect cowpea cultivars as a function of water shortfall. The experiment was conducted in experimental area of Federal University of Mato Grosso state, Brazil. Was evaluated the germination rate, foliar area, shoot and root dry matter production and diameter of the stem of the BRS Nova Era, BRS Tumucumaque and BRS Imponente, in function of four different water shortfall (0; 4; 8 and 12 days without water. The experiment delineation adopted was a factorial design 3 x 4. The cultivars BRS Tumucumaque had a higher number to sprouting seeds, shoot and root dry mass production and diameter of the stem. Perhaps the cultivar BRS Tucmucumaque had a growth sharp decline with 12 days in water shortfall.

A Light-curve Analysis of 32 Recent Galactic Novae: Distances and White Dwarf Masses

Abstract We obtained the absolute magnitudes, distances, and white dwarf (WD) masses of 32 recent galactic novae based on the time-stretching method for nova light curves. A large part of the light/color curves of two classical novae often overlap each other if we properly squeeze/stretch their timescales. Then, a target nova brightness is related to the other template nova brightness by , where t is the time, M V [t] is the absolute V magnitude, and f s is their timescaling ratio. Moreover, when these two time-stretched light curves, (t/f s)–(M V − 2.5 log f s), overlap each other, (t/f s)–(B − V)0 do too, where (B − V)0 is the intrinsic B − V color. Thus, the two nova tracks overlap each other in the (B − V)0–(M V − 2.5 log f s) diagram. Inversely, using these properties, we obtain/confirm the distance and reddening by comparing each nova light/color curves with well-calibrated template novae. We classify the 32 novae into two types, LV Vul and V1500 Cyg, in the time-stretched (B − V)0–(M V − 2.5 log f s) color–magnitude diagram. The WD mass is obtained by direct comparison of the model V light curves with the observation. Thus, we obtain a uniform set of 32 galactic classical novae that provides the distances and WD masses from a single method. Many novae broadly follow the universal decline law and the present method can be applied to them, while some novae largely deviate from the universal decline law and so the method cannot be directly applied to them. We discuss such examples.

Precise measures of orbital period, before and after nova eruption for QZ Aurigae

For the ordinary classical nova QZ Aurigae (which erupted in 1964), we report 1317 magnitudes from 1912--2016, including four eclipses detected on archival photographic plates from long before the eruption. We have accurate and robust measures of the orbital period both pre-eruption and post-eruption, and we find that the orbital period decreased, with a fractional change of -290.71+-0.28 parts-per-million across the eruption, with the orbit necessarily getting smaller. Further, we find that the light curve outside of eclipses and eruption is flat at near B=17.14 from 1912--1981, whereupon the average light curve starts fading down to B=17.49 with large variability. QZ Aur is a robust counter-example against the Hibernation model for the evolution of cataclysmic variables, where the model requires that all novae have their period increase across eruptions. Large period decreases across eruptions can easily arise from mass imbalances in the ejecta, as are commonly seen in asymmetric nova shells.

Measurement of the neutrino oscillation parameters by NOvA

Using a beam made (mainly) by muon neutrinos traveling through the earth, the NOvA Experiment looks for the appearance of electron neutrinos, a transformation explained by the quantum-mechanical phenomenon known as neutrino oscillation. NOvA uses two neutrino detectors located 14.6 mrad off-axis from the main beam direction. The first (Near) detector stands at a distance of 1 km from the neutrino source, while the second (Far) one is at 810 km. Traveling from the Near Detector to the Far Detector, muon neutrinos can morph into electron neutrinos with a probability depending upon the parameters and sin2 θ23, among others. By comparing the observed number of νµ and νe events at the Far Detector with the expected number of events predicted by a 3-neutrino oscillation model, NOvA is able to measure these parameters and help to improve our understanding about neutrinos. After a brief introduction to the physics of neutrinos and a presentation of the experiment, in this talk the most recent results obtained by NOvA through the study of muon neutrino oscillations νµ → νµ and νµ → νe, are shown. The oscillation parameters are found to be and sin2 θ23 = 0.56.

Testing of quasi-elastic neutrino charged-current and two-body meson exchange current models with the MiniBooNE neutrino data and analysis of these processes at energies available at the NOvA experiment

The charged-current quasi-elastic (CCQE) scattering of muon neutrinos on a carbon target is analyzed using the relativistic distorted-wave impulse approximation (RDWIA) taking into account the contribution of the two-particle and two-hole meson exchange current ($2p-2h$ MEC) to the weak response functions. A fit the RDWIA+MEC model to the MiniBooNE neutrino data is performed and the best fit value of nucleon axial mass $M_A=1.2 \pm 0.06$ GeV is obtained. We also extract the values of the axial form factor $F_A(Q^2)$ as a function of the squared momentum transfer $Q^2$ from the measured $d\sigma/dQ^2$ cross section. The flux-integrated CCQE-like differential cross sections for neutrino scattering at energies of the NOvA experiment are estimated within the RDWIA+MEC approach.

AT 2017fvz: a nova in the dwarf irregular galaxy NGC 6822

ABSTRACT A transient in the Local Group dwarf irregular galaxy NGC 6822 (Barnard’s Galaxy) was discovered on 2017 August 2 and is only the second classical nova discovered in that galaxy. We conducted optical, near-ultraviolet, and X-ray follow-up observations of the eruption, the results of which we present here. This ‘very fast’ nova had a peak V-band magnitude in the range −7.41 > MV > −8.33 mag, with decline times of t2,V = 8.1 ± 0.2 d and t3,V = 15.2 ± 0.3 d. The early- and late-time spectra are consistent with an Fe ii spectral class. The H α emission line initially has a full width at half-maximum intensity of ∼2400 km s−1 – a moderately fast ejecta velocity for the class. The H α line then narrows monotonically to ∼1800 km s−1 by 70 d post-eruption. The lack of a pre-eruption coincident source in archival Hubble Space Telescope imaging implies that the donor is a main-sequence, or possibly subgiant, star. The relatively low-peak luminosity and rapid decline hint that AT 2017fvz may be a ‘faint and fast’ nova.

Quenched Nitrogen-included Carbonaceous Composite (QNCC): A powerful candidate of the carriers of the UIR bands in classical novae

AbstractWe have succeeded in synthesizing organics, ‘Quenched Nitrogen-included Carbonaceous Composite (QNCC)’, via plasma chemical vapor deposition (CVD) method, whose infrared spectral properties reproduce the characteristics of the unidentified infrared (UIR) bands observed around classical novae. Past studies have shown that the UIR bands observed around novae appear somewhat differently from those observed in other astrophysical environment and are predominantly characterized by the presence of a broad 8μm feature. The remarkable similarity between the infrared properties of QNCC and the UIR bands in novae indicates that QNCC should be considered as a strong candidate of the carriers of the UIR bands in novae. Finally, we have started a space exposure experiment of QNCC aiming to explore the evolutional link between the QNCC and the insoluble organic molecule (IOM) in carbonaceous condrite and, thus, to infer the origins of organics in our solar system.

LMC S154: the first Magellanic symbiotic recurrent nova

Classical nova outburst has been suggested for a number of extragalactic symbiotic stars, but in none of the systems has it been proven. In this work we study the nature of one of these systems, LMC S154. We gathered archival photometric observations in order to determine the timescales and nature of variability in this system. Additionally we carried out photometric and spectroscopic monitoring of the system and fitted synthetic spectra to the observations. Carbon abundance in the photosphere of the red giant is significantly higher than that derived for the nebula, which confirms pollution of the circumbinary material by the ejecta from nova outburst. The photometric and spectroscopic data show that the system reached quiescence in 2009, which means that for the first time all of the phases of a nova outburst were observed in an extragalactic symbiotic star. The data indicate that most probably there were three outbursts observed in LMC S154, which would make this system a member of a rare class of symbiotic recurrent novae. The recurrent nature of the system is supported by the discovery of coronal lines in the spectra, which are observed only in symbiotic stars with massive white dwarfs and with short-recurrence-time outbursts. Gathered evidence is sufficient to classify LMC S154 as the first bona fide extragalactic symbiotic nova, which is likely a recurrent nova. It is also the first nova with a carbon-rich donor.

The asymptotic evolution of the stellar merger V1309 Sco: a Blue Straggler in the making?

Stellar mergers are estimated to be common events in the Galaxy. The best studied stellar merger case to date is V1309 Sco (= Nova Scorpii 2008) which was originally misclassified as a Nova event. Later identified as the merger of the components of a cool overcontact binary system with 1.52 Msun and 0.16 Msun, V1309 Sco showed an initial period of P = 1.4 days before the merger. Post-outburst evolution demonstrated that V1309 Sco was unlike the typical Classical Novae and Symbiotic Recurrent Novae with significant dust production around it, and indicated that the system may become a post-AGB (or pre-PN) soon. Here we present a study of V1309 Sco about ten years after the outburst, based on near-IR variability and colour data from the ESO surveys VISTA Variables in the V\'{i}a L\'actea (VVV) and VVV eXtended (VVVX). We find that reasonable equilibrium in this stellar merger is being reached and that the star has settled into a nearly constant magnitude. A dramatic change in its near-IR colours from (J-Ks) = 1.40 in 2010 to (J-Ks) = 0.42 in 2015 and a possible low amplitude periodic signal with P = 0.49 days in the post-outburst data are consistent with a "blue straggler" star, predicted to be formed from a stellar merger.

A Hubble Space Telescope Survey for Novae in the Globular Clusters of M87∗

Abstract The giant elliptical galaxy M87 has been imaged over 30 consecutive days in 2001, 60 consecutive days in 2005–2006, and every 5 days over a 265-day span in 2016–2017 with the Hubble Space Telescope, leading to the detection of 137 classical novae throughout M87. We have identified 2134 globular clusters (GC) in M87 in these images and carried out searches of the clusters for classical novae erupting in or near them. One GC CN was detected in the 2001 data, while zero novae were found during the 2005–2006 observations. Four candidate GC novae were (barely) detected in visible light during the 2016–2017 observations, but none of the four were seen in near-ultraviolet light, leading us to reject them. Combining these results with our detection of one M87 GC nova out of a total of 137 detected CN, we conclude that such novae may be overabundant relative to the field, but small number statistics dominate this and all other searches. A definitive determination of GC CN overabundance (or not) will require much larger samples, which LSST should provide in the coming decade.

A Shocking Shift in Paradigm for Classical Novae

The discovery of GeV gamma-rays from classical novae has led to a reassessment of these garden-variety explosions, and highlighted their importance for understanding radiative shocks, particle acceleration, and dust formation in more exotic, distant transients.

Different types of fertilization and spacing in the culture of the city without municipality of Nova Xavantina-MT

The rocket (Eruca sativa Hill.), Is a vegetable which has shown tremendous growth in its demand as compared to the cultivation of other hardwoods. This study aimed to evaluate the production of rocket due to row spacing and fertilization. The seeds were sown in the garden of Goias, in the municipality of Nova Xavantina-MT. The experimental design was a randomized block design with three replications. The treatments were arranged in a factorial 3 x 3, three plant spacing (20 x 5, 25 x 5 e 30 cm x 5 cm) and three fertilization (organic, mineral and organic mineral). The cultivar used was Cultivada arugula, sown directly into beds using 4-7 seeds per hole. Plants were harvested 31 days after sowing. The variables studied were: green mass, dry mass, plant height, leaf number and leaf area. No significant interaction between spacing and fertilization in any of the traits.

Growth of churches submitted to different doses of hydrogel and containers

The cultivation of rubber trees in Brazil has been established as a sustainable and profitable activity, despite all the challenges, the production of rubber trees grows considerably each year. In order to optimize this production, it is necessary to develop techniques for the production of seedlings that present vigor and quality. Therefore, the objective of this work was to evaluate the growth of rubber tree seedlings submitted to different doses of hydrogel and containers. The work was carried out in the seedling nursery of the State University of Mato Grosso, Campus Nova Xavantina. The dosages used were 0, 1, 2, 3 and 4g and the containers were polyethylene bags in dimensions 20x30 and 25x35 cm. To evaluate the effect of the treatments on the growth of the rubber tree seedlings the following variables were measured at 90 days after sowing: Height (cm), stem diameter (mm), H / D ratio, number of triphophils, root length), Dry matter of the leaves (g), dry matter of the stem (g), dry matter root (g). The experimental design was a randomized complete block (DBC) in a 2x5 factorial scheme, two containers and five hydrogel doses, with six replicates for each treatment. From the results obtained in the present work it can be concluded that the dosage of 1g.L -1 of hydrogel and the container 25x35 cm were the most suitable treatments for the initial development of the rubber tree seedlings.

A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD

We combine the results of our earlier study of the UV characteristics of 18 classical novae (CNe) with data from the literature and with the recent precise distance determinations from the Gaia satellite to investigate the statistical properties of old novae. All final parameters for the sample include a detailed treatment of the errors and their propagation. The physical properties reported here include the absolute magnitudes at maximum and minimum, a new maximum magnitude versus rate of decline (MMRD) relation, and the inclination-corrected 1100–6000 Å accretion disk luminosity. Most importantly, these data have allowed us to derive a homogenous set of accretion rates in quiescence for the 18 novae. All novae in the sample were super-Eddington during outburst, with an average absolute magnitude at maximum of −7.5 ± 1.0. The average absolute magnitude at minimum corrected for inclination is 3.9 ± 1.0. The median mass accretion rate is log Ṁ1 M⊙ = −8.52 (using 1 M⊙ as WD mass for all novae) or log ṀMWD = −8.48 (using the individual WD masses). These values are lower than those assumed in studies of CNe evolution and appear to attenuate the need for a hibernation hypothesis to interpret the nova phenomenon. We identified a number of correlations among the physical parameters of the quiescent and eruptive phases, some already known but others new and even surprising. Several quantities correlate with the speed class t3 including, unexpectedly, the mass accretion rate (Ṁ). This rate correlates also with the absolute magnitude at minimum corrected for inclination, and with the outburst amplitude, providing new and simple ways to estimate Ṁ through its functional dependence on (more) easily observed quantities. There is no correlation between Ṁ and the orbital period.

Continuous Integration service at Fermilab

This paper describes the current architecture of Continuous Integration (CI) service developed at Fermilab, encountered successes and difficulties, as well as future development plans. The current experiment code has hundreds of contributors that provide new features, bug fixes, and other improvements. Version control systems help developers to collaborate in contributing software for their experiments, while the CI system helps developers keep their code healthy. The Fermilab CI service allows experiments and projects to test and validate their offline production and analysis code on the supported platforms. It is built on top of Jenkins, designed to be set up from a configuration file that provides implementation for each phase of the CI workflow, and able to validate experiment code through grid jobs. This CI service provides a dashboard for easy access to logs and statistical graphs. Since the CI service has been adopted by Fermilab experiments/projects, it proved to be very useful to intercept issues in their code early on and get them fixed before running it in production. Currently the CI service is in use by the ArgoNeuT, DUNE, g-2, LArIAT, MINERvA, mu2e, NOvA, SBND and uBooNE experiments and by the following projects: ART and LArSoft software suites, GENIE, and Glidein-WMS. The CI service is under active development and planning to support code profiling.

Implementation of Feldman-Cousins corrections and oscillation calculations in the HPC environment for the NOvA Experiment

Analysis of neutrino oscillation data involves a combination of complex fitting procedures and statistical correction techniques that are used to determine the full three-flavor PMNS parameters and constraint contours. These techniques rely on computationally intensive “multi-universe” stochastic modeling. The process of calculating these contours and corrections can dominate final stages of the data analysis and become a bottleneck for examining the ef-fect of systematic variations on the final results. As part of the DOE SciDAC-4 sponsored research program, we present a new implementation of a neutrino oscillation fitting and framework to carry out calculations of Feldman-Cousins corrections. This implementation is specifically designed and optimized to operate on modern High-Performance Computing (HPC) facilities. We present the performance of the system in calculating allowed regions for the NOvA experiment based on 8.9 x 1020 and 6.9 x 1020 protons-on-target (POT) neutrino and antineutrino datasets, and compare the performance of this new implementation run at the NERSC supercomputing facility with that from methods used previously by the NOvA collaboration running on grid computing facilities.

Measuring the Expansion and Age of the Nova Shell IPHASX J210204.7+471015

The parallax expansion and kinematics of a nova shell can be used to assess its age and distance, and to investigate the interaction of the ejecta with the circumstellar medium. These are key to understand the expansion and dispersal of the nova ejecta in the Galaxy. Multi-epoch images and high-dispersion spectroscopic observations of the recently discovered classical nova shell IPHASXJ210204.7+471015 around a nova-like system have been used to derive a present day expansion rate of 0.100 arcsec/yr and an expansion velocity of 285 km/s. These data are combined to obtain a distance of 600 pc to the nova. The secular expansion of the nova shell place the event sometime between 1850 and 1890, yet it seems to have been missed at that time. Despite its young age, 130-170 yrs, we found indications that the ejecta has already experienced a noticeable deceleration, indicating the interaction of this young nova shell with the surrounding medium.