The X-Ray Time Variability and Spectrum of Gamma-Cassiopeiae X:0053+604

NASA Astrophysics Data System (ADS)

Parmar, A. N.; Israel, G. L.; Stella, L.; White, N. E.

1993-08-01

A 30 h duration EXOSAT observation made in 1985 December is used to examine the X-ray time variability and spectrum of the Be star γ Cassiopeiae (X 0053+604). We find that the X-ray lightcurve is dominated by irregular energy-independent flaring on time-scales ≳ 100 s. This flaring markedly decreases the sensitivity to any periodic signals. We find no evidence for the 6000 5 oscillations reported by Frontera et al. (1987) from an earlier EXOSAT observation. We suggest that these arise from statistical fluctuations in the red noise power. The X-ray spectrum of γ Cas can either be modeled by thermal emission from an optically thin plasma with a temperature of 12 keV, or by a cut-off power-law model with a narrow iron line at an energy of 6.67 keV. The origin of the X-ray emission in this system remains open since its spectral and temporal properties are consistent with both an acereting neutron star and a white dwarf while its high temperature argues against a coronal mechanism.

A Year in the Life of an Infrared Echo

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Figure 1: Supernova Remnant Cassiopeia A One Year Apart

These Spitzer Space Telescope images, taken one year apart, show the supernova remnant Cassiopeia A (yellow ball) and surrounding clouds of dust (reddish orange). The pictures illustrate that a blast of light from Cassiopeia A is waltzing outward through the dusty skies. This dance, called an 'infrared echo,' began when the remnant erupted about 50 years ago.

Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion 325 years ago. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. This remnant is located 10,000 light-years away in the northern constellation Cassiopeia.

Infrared echoes are created when a star explodes or erupts, flashing light into surrounding clumps of dust. As the light zips through the dust clumps, it heats them up, causing them to glow successively in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. Echoes are distinct from supernova shockwaves, which are made up material that is swept up and hurled outward by exploding stars.

This infrared echo is the largest ever seen, stretching more than 50 light-years away from Cassiopeia A. If viewed from Earth, the entire movie frame would take up the same amount of space as two full moons.

Hints of an older infrared echo from Cassiopeia A's supernova explosion hundreds of years ago can also be seen.

The top Spitzer image was taken on November 30, 2003, and the bottom, on December 2, 2004.

X-Ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A

NASA Astrophysics Data System (ADS)

Sato, Toshiki; Katsuda, Satoru; Morii, Mikio; Bamba, Aya; Hughes, John P.; Maeda, Yoshitomo; Ishida, Manabu; Fraschetti, Federico

2018-01-01

We present new evidence that the bright nonthermal X-ray emission features in the interior of the Cassiopeia A supernova remnant are caused by inward-moving shocks, based on Chandra and NuSTAR observations. Several bright inward-moving filaments were identified using monitoring data taken by Chandra in 2000–2014. These inward-moving shock locations are nearly coincident with hard X-ray (15–40 keV) hot spots seen by NuSTAR. From proper-motion measurements, the transverse velocities were estimated to be in the range of ∼2100–3800 km s‑1 for a distance of 3.4 kpc. The shock velocities in the frame of the expanding ejecta reach values of ∼5100–8700 km s‑1, which is slightly higher than the typical speed of the forward shock. Additionally, we find flux variations (both increasing and decreasing) on timescales of a few years in some of the inward-moving shock filaments. The rapid variability timescales are consistent with an amplified magnetic field of B ∼ 0.5–1 mG. The high speed and low photon cut-off energy of the inward-moving shocks are shown to imply a particle diffusion coefficient that departs from the Bohm regime (k 0 = D 0/D 0,Bohm ∼ 3–8) for the few simple physical configurations we consider in this study. The maximum electron energy at these shocks is estimated to be ∼8–11 TeV, which is smaller than the values of ∼15–34 TeV that were inferred for the forward shock. Cassiopeia A is dynamically too young for its reverse shock to appear to be moving inward in the observer frame. We propose instead that the inward-moving shocks are a consequence of the forward shock encountering a density jump of ≳5–8 in the surrounding material.

Space Science

NASA Image and Video Library

2000-01-01

The colorful streamers that float across the sky in this photo taken by NASA's Hubble Space Telescope (HST) were created by the universe's biggest firecracker, the titanic supernova explosion of a massive star. The light from the exploding star reached Earth 320 years ago, nearly a century before the United States celebrated its birth with a bang. The dead star's shredded remains are called Cassiopeia A, or "Cas A" for short. Cas A is the youngest known supernova remnant in our Milky Way Galaxy and resides 10,000 light-years away in the constellation Cassiopeia, so the star actually blew up 10,000 years before the light reached Earth in the late 1600s. This HST image of Cas A shows for the first time that the debris is arranged into thousands of small, cooling knots of gas. This material eventually will be recycled into building new generations of stars and planets. Our own Sun and planets are constructed from the debris of supernovae that exploded billions of years ago. This photo shows the upper rim of the super nova remnant's expanding shell. Near the top of the image are dozens of tiny clumps of matter. Each small clump, originally just a small fragment of the star, is tens of times larger than the diameter of our solar system. The colors highlight parts of the debris where chemical elements are glowing. The dark blue fragments, for example, are richest in oxygen; the red material is rich in sulfur. The images were taken with the Wide Field and Planetary Camera 2 in January 2000 and January 2002. Image Credit: NASA and HST team (Stoics/AURA). Acknowledgment: R. Fesen (Darmouth) and J. Morse ( Univ. of Colorado).

History of Chandra X-Ray Observatory

NASA Image and Video Library

2004-08-23

This spectacular Chandra X-Ray Observatory (CXO) image of the supernova remnant Cassiopeia A is the most detailed image ever made of the remains of an exploded star. The one-million-second image shows a bright outer ring (green) 10 light years in diameter that marks the location of a shock wave generated by the supernova explosion. In the upper left corner is a large jet-like structure that protrudes beyond the shock wave, and a counter-jet can be seen on the lower right. The x-ray spectra show that the jets are rich in silicon atoms, and relatively poor in iron atoms. This indicates that the jets formed soon after the initial explosion of the star, otherwise, the jets should have contained large quantities of iron from the star’s central regions. The bright blue areas are composed almost purely of iron gas, which was produced in the central, hottest regions of the star and somehow ejected in a direction almost perpendicular to the jets. The bright source at the center of the image is presumed to be a neutron star created during the supernova. Unlike most others, this neutron star is quiet, faint, and so far shows no evidence of pulsed radiation. A working hypothesis is that the explosion that created Cassiopeia A produced high speed jets similar to, but less energetic than, the hyper nova jets thought to produce gamma-ray bursts. During the explosion, the star may have developed an extremely strong magnetic filed that helped to accelerate the jets and later stifled any pulsar wind activity. CXO project management is the responsibility of NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Deepest Image of Exploded Star Uncovers Bipolar Jets

NASA Technical Reports Server (NTRS)

2004-01-01

This spectacular Chandra X-Ray Observatory (CXO) image of the supernova remnant Cassiopeia A is the most detailed image ever made of the remains of an exploded star. The one-million-second image shows a bright outer ring (green) 10 light years in diameter that marks the location of a shock wave generated by the supernova explosion. In the upper left corner is a large jet-like structure that protrudes beyond the shock wave, and a counter-jet can be seen on the lower right. The x-ray spectra show that the jets are rich in silicon atoms, and relatively poor in iron atoms. This indicates that the jets formed soon after the initial explosion of the star, otherwise, the jets should have contained large quantities of iron from the star's central regions. The bright blue areas are composed almost purely of iron gas, which was produced in the central, hottest regions of the star and somehow ejected in a direction almost perpendicular to the jets. The bright source at the center of the image is presumed to be a neutron star created during the supernova. Unlike most others, this neutron star is quiet, faint, and so far shows no evidence of pulsed radiation. A working hypothesis is that the explosion that created Cassiopeia A produced high speed jets similar to, but less energetic than, the hyper nova jets thought to produce gamma-ray bursts. During the explosion, the star may have developed an extremely strong magnetic filed that helped to accelerate the jets and later stifled any pulsar wind activity. CXO project management is the responsibility of NASA's Marshall Space Flight Center in Huntsville, Alabama.

Fermi-LAT Gamma-Ray Detections of Classical Novae V1369 Centauri 2013 and V5668 Sagittarii 2015

NASA Astrophysics Data System (ADS)

Cheung, C. C.; Jean, P.; Shore, S. N.; Stawarz, Ł.; Corbet, R. H. D.; Knödlseder, J.; Starrfield, S.; Wood, D. L.; Desiante, R.; Longo, F.; Pivato, G.; Wood, K. S.

2016-08-01

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

Discovery of an old nova shell surrounding the cataclysmic variable V1315 Aql

NASA Astrophysics Data System (ADS)

Sahman, D. I.; Dhillon, V. S.; Littlefair, S. P.; Hallinan, G.

2018-07-01

Following our tentative discovery of a faint shell around V1315 Aql reported in Sahman et al., we undertook deep Hα imaging and intermediate-resolution spectroscopy of the shell. We find that the shell has its geometric centre located on V1315 Aql. The mass, spectral features, and density of the shell are consistent with other nova shells, rather than planetary nebulae or supernova remnants. The radial velocity of the shell is consistent with the systemic velocity of V1315 Aql. We believe this evidence strongly suggests that the shell originates from an earlier nova event. This is the first nova shell discovered around a nova-like and supports the theory of nova-induced cycles in mass transfer rates (hibernation theory) first proposed by Shara et al.

A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

NASA Astrophysics Data System (ADS)

Finzell, Thomas; Chomiuk, Laura; Metzger, Brian D.; Walter, Frederick M.; Linford, Justin D.; Mukai, Koji; Nelson, Thomas; Weston, Jennifer H. S.; Zheng, Yong; Sokoloski, Jennifer L.; Mioduszewski, Amy; Rupen, Michael P.; Dong, Subo; Starrfield, Sumner; Cheung, C. C.; Woodward, Charles E.; Taylor, Gregory B.; Bohlsen, Terry; Buil, Christian; Prieto, Jose; Wagner, R. Mark; Bensby, Thomas; Bond, I. A.; Sumi, T.; Bennett, D. P.; Abe, F.; Koshimoto, N.; Suzuki, D.; Tristram, P. J.; Christie, Grant W.; Natusch, Tim; McCormick, Jennie; Yee, Jennifer; Gould, Andy

2018-01-01

It has recently been discovered that some, if not all, classical novae emit GeV gamma-rays during outburst, but the mechanisms involved in the production ofgamma-rays are still not well understood. We present here a comprehensive multiwavelength data set—from radio to X-rays—for the most gamma-ray-luminous classical nova to date, V1324 Sco. Using this data set, we show that V1324 Sco is a canonical dusty Fe II-type nova, with a maximum ejecta velocity of 2600 km s‑1 and an ejecta mass of a few × {10}-5 {M}ȯ . There is also evidence for complex shock interactions, including a double-peaked radio light curve which shows high brightness temperatures at early times. To explore why V1324 Sco was so gamma-ray luminous, we present a model of the nova ejecta featuring strong internal shocks and find that higher gamma-ray luminosities result from higher ejecta velocities and/or mass-loss rates. Comparison of V1324 Sco with other gamma-ray-detected novae does not show clear signatures of either, and we conclude that a larger sample of similarly well-observed novae is needed to understand the origin and variation of gamma-rays in novae.

A cut-off in the TeV gamma-ray spectrum of the SNR Cassiopeia A

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colak, M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Inada, T.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.

2017-12-01

It is widely believed that the bulk of the Galactic cosmic rays is accelerated in supernova remnants (SNRs). However, no observational evidence of the presence of particles of PeV energies in SNRs has yet been found. The young historical SNR Cassiopeia A (Cas A) appears as one of the best candidates to study acceleration processes. Between 2014 December and 2016 October, we observed Cas A with the MAGIC telescopes, accumulating 158 h of good quality data. We derived the spectrum of the source from 100 GeV to 10 TeV. We also analysed ∼8 yr of Fermi-LAT to obtain the spectral shape between 60 MeV and 500 GeV. The spectra measured by the LAT and MAGIC telescopes are compatible within the errors and show a clear turn-off (4.6σ) at the highest energies, which can be described with an exponential cut-off at E_c = 3.5(^{+1.6}_{-1.0})_{stat} (^{+0.8}_{-0.9})_{sys} TeV. The gamma-ray emission from 60 MeV to 10 TeV can be attributed to a population of high-energy protons with a spectral index of ∼2.2 and an energy cut-off at ∼10 TeV. This result indicates that Cas A is not contributing to the high energy (∼PeV) cosmic ray sea in a significant manner at the present moment. A one-zone leptonic model fails to reproduce by itself the multiwavelength spectral energy distribution. Besides, if a non-negligible fraction of the flux seen by MAGIC is produced by leptons, the radiation should be emitted in a region with a low magnetic field (B⪅180 μG) like in the reverse shock.

First NICER Observations of the Enigmatic Be Star, Gamma Cassiopeiae

NASA Astrophysics Data System (ADS)

Hamaguchi, Kenji; Drake, Stephen; Corcoran, Michael; Gendreau, Keith C.; Steiner, Jack; NICER team

2018-01-01

Gamma Cassiopeiae is an enigmatic Be star with unusually hard, strong X-ray emission compared with normal main-sequence B stars (but a much lower X-ray luminosity than the classic X-ray binaries). The X-ray characteristics - hot (kT ~12 keV), thermal plasma spectrum and rapid time variations on timescales of 10-1000 sec - is reminiscent of accreting compact objects. Alternatively, its shot-like rapid variations somewhat resemble solar-type magnetic reconnection flares, so that plasma heating by the star-disk magnetic dynamo of the Be star has been proposed. A recent discovery of rapid X-ray color variations with the Suzaku X-ray observatory revealed the presence of rapidly moving absorbers in the X-ray line of sight, giving a strong constraint on the geometry of the X-ray emitting regions and absorbers.The X-ray observatory onboard ISS, NICER, has observed Gamma Cas multiple times. The large collecting area in the 0.3-10 keV band, tolerance to photon pile-ups, and decent energy resolution in particular below 1 keV, should provide excellent pieces of information on how the X-ray emission and/or absorbing column change on short timescales. We will present the first result of the gamma Cas observations made by the NICER observatory.

Life after eruption VII: A search for stunted outbursts in thirteen post-novae

NASA Astrophysics Data System (ADS)

Vogt, N.; Tappert, C.; Puebla, E. C.; Fuentes-Morales, I.; Ederoclite, A.; Schmidtobreick, L.

2018-06-01

The results of a photometric campaign during three observing seasons 2013 - 2016 at the Cerro Tololo International Observatory (1.3-meter SMARTS telescope) are presented. The aim was to detect "stunted" outbursts in a total of 13 post novae more than 38 years after maximum brightness registered in their nova eruption light curve. In six of the targets (V728 Sco 1862, V1059 Sgr 1898, V849 Oph 1919, V363 Sgr 1927, HS Pup 1963 and V2572 Sgr 1969) we detected such dwarf nova-like mini-outbursts, with mean amplitudes between 0.2m and 2.2m and typical FWHM of 4-11 days, repeating every 9-32 days. The most regular outburst behavior is present in the eclipsing post-nova V728 Sco. In our sample there is no significant correlation between the occurrences of stunted outbursts and the time passed since the nova eruption maximum. However, considering all 15 post-novae that have been reported to show stunted outbursts we found a possible tendency for increasing outburst amplitudes at the rate 0.52 ± 0.23 mag/century during 30 - 250 years after nova eruption. This tendency is still doubtful due to the low number of cases available. If the stunted outburst activity is related to the mass transfer rate \\dot{M}, we conclude that the secular decrease of \\dot{M} predicted by the hibernation scenario must be at much longer time scales than ˜200 years actually covered with post-nova observations.

Fermi-LAT gamma ray detections of classical novae V1369 centauri 2013 and V5668 Sagittarii 2015

DOE PAGES

Cheung, C. C.; Jean, P.; Shore, S. N.; ...

2016-07-27

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

Cassiopeia A: Death Becomes Her

NASA Technical Reports Server (NTRS)

2005-01-01

This stunning false-color picture shows off the many sides of the supernova remnant Cassiopeia A. It is made up of images taken by three of NASA's Great Observatories, using three different wavebands of light. Infrared data from the Spitzer Space Telescope are colored red; visible data from the Hubble Space Telescope are yellow; and X-ray data from the Chandra X-ray Observatory are green and blue.

Located 10,000 light-years away in the northern constellation Cassiopeia, Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion 325 years ago. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. The neutron star can be seen in the Chandra data as a sharp turquoise dot in the center of the shimmering shell.

Each Great Observatory highlights different characteristics of this celestial orb. While Spitzer reveals warm dust in the outer shell about a few hundred degrees Kelvin (80 degrees Fahrenheit) in temperature, Hubble sees the delicate filamentary structures of hot gases about 10,000 degrees Kelvin (18,000 degrees Fahrenheit). Chandra probes unimaginably hot gases, up to about 10 million degrees Kelvin (18 million degrees Fahrenheit). These extremely hot gases were created when ejected material from Cassiopeia A smashed into surrounding gas and dust. Chandra can also see Cassiopeia A's neutron star (turquoise dot at center of shell).

Blue Chandra data were acquired using broadband X-rays (low to high energies); green Chandra data correspond to intermediate energy X-rays; yellow Hubble data were taken using a 900 nanometer-wavelength filter, and red Spitzer data are from the telescope's 24-micron detector.

The animation begins with the false-color picture of the supernova remnant Cassiopeia A. It then pans out to show a Spitzer view of Cassiopeia A (yellow ball) and surrounding clouds of dust (reddish orange). Here, the animation flips back and forth between two Spitzer images taken one year apart. A blast of light from Cassiopeia A is seen waltzing through the dusty skies. Called an 'infrared echo,' this dance began when the remnant's dead star erupted, or 'turned in its grave,' about 50 years ago.

Infrared echoes are created when a star explodes or erupts, flashing light into surrounding clumps of dust. As the light zips through the dust clumps, it heats them up, causing them to glow successively in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. Echoes are distinct from supernova shockwaves, which are made up material that is swept up and hurled outward by exploding stars.

This infrared echo is the largest ever seen, stretching more than 50 light-years away from Cassiopeia A. If viewed from Earth, the entire movie frame would take up the same amount of space as two full moons.

Hints of an older infrared echo from Cassiopeia A's supernova explosion hundreds of years ago can also be seen.

The earlier Spitzer image was taken on November 30, 2003, and the later, on December 2, 2004.

A deep optical imaging study of the nebular remnants of classical novae

NASA Astrophysics Data System (ADS)

Slavin, A. J.; O'Brien, T. J.; Dunlop, J. S.

1995-09-01

An optical imaging study of old nova remnants has revealed previously unobserved features in the shells of 13 classical novae - DQ Her, FH Ser, HR Del, GK Per, V1500 Cyg, T Aur, V533 Her, NQ Vul, V476 Cyg, DK Lac, LV Vul, RW UMi and V450 Cyg. These data indicate a possible correlation between nova speed class and the ellipticity of the resulting remnants - those of faster novae tend to comprise randomly distributed clumps of ejecta superposed on spherically symmetric diffuse material, whilst slower novae produce more structured ellipsoidal remnants with at least one and sometimes several rings of enhanced emission. By measuring the extent of the resolved shells and combining this information with previously published ejection speeds, we use expansion parallax to estimate distances for the 13 novae. Whilst we are able to deduce new information about every nova, it is notable that these observations include the first detections of shells around the old novae V450 Cyg and NQ Vul, and that velocity-resolved images of FH Ser and DQ Her have enabled us to estimate their orbital inclinations. Our observations of DQ Her also show that the main ellipsoidal shell is constricted by three rings and surrounded by a faint halo; this halo contains long tails extending outwards from bright knots, perhaps indicating that during or after outburst a fast inner wind has broken through the fractured principal shell.

Spectroscopic and Photometric Behaviour of Nova Cygni 1992 IN the First Nine Months Following Outburst

NASA Astrophysics Data System (ADS)

Chochol, D.; Hric, L.; Urban, Z.; Komzik, R.; Grygar, J.; Papousek, J.

1993-09-01

We present the results of UBV photometry and high dispersion 360-500 nm spectroscopy of Nova Cygni 1992 (= V 1974 Cyg), obtained between February 25 and November 9, 1992. Our data cover the early decline, transition and nebular stages of the evolution of the nova. We discuss the photometric and spectroscopic behaviour of the star during the first nine months after outburst and briefly compare our findings with the data already published by other authors. We have classified the nova as a fast one with t2,V = 16 d, t2,B = 23 d, and t3,V = 42 d, t3,B = 51 d. We have derived the absolute magnitudes of the nova at maximum to be M0,V = -7.67 and M0,B = -7.49. The latter value yields a mass of 0.83 Msun for the white dwarf component. The values of the distance modulus 12.23 and the colour excess EB-V = +0.32 correspond to a distance r = 1.77 kpc. We have found a period of 0.814 days by period analysis of photoelectric V data obtained before the nova declined 3m. During the nebular stage, forbidden lines of highly ionized neon were prominent, confirming the 0-Ne-Mg classification of the nova. The outburst of Nova Cygni 1992 was apparently caused by a super-Eddington thermonuclear runaway on the surface of an evolutionarily eroded O-Ne-Mg white dwarf.

Discovery of an old nova shell surrounding the cataclysmic variable V1315 Aql

NASA Astrophysics Data System (ADS)

Sahman, D. I.; Dhillon, V. S.; Littlefair, S. P.; Hallinan, G.

2018-04-01

Following our tentative discovery of a faint shell around V1315 Aql reported in Sahman et al. (2015), we undertook deep Hα imaging and intermediate-resolution spectroscopy of the shell. We find that the shell has its geometric centre located on V1315 Aql. The mass, spectral features and density of the shell are consistent with other nova shells, rather than planetary nebulae or supernova remnants. The radial velocity of the shell is consistent with the systemic velocity of V1315 Aql. We believe this evidence strongly suggests that the shell originates from an earlier nova event. This is the first nova shell discovered around a novalike, and supports the theory of nova-induced cycles in mass transfer rates (hibernation theory) first proposed by Shara et al. (1986).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hachisu, Izumi; Kato, Mariko, E-mail: hachisu@ea.c.u-tokyo.ac.jp, E-mail: mariko@educ.cc.keio.ac.jp

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 massmore » 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.« less

Nova V2214 Ophiuchi 1988 - A magnetic nova inside the period gap

NASA Technical Reports Server (NTRS)

Baptista, R.; Jablonski, F. J.; Cieslinski, D.; Steiner, J. E.

1993-01-01

The discovery of a coherent photometric modulation in Nova Oph 1988 with period 0.117515 +/- 0.000002 d, which is associated with the orbital period of the underlying binary, is reported. On the basis of photometric observations, it is concluded that Nova V2214 Oph 1988 is a magnetic nova with an orbital period inside the period gap. The inclusion of this system in the statistics of novae suggests that there is no period gap for novae and that there is a clear correlation between the occurrence of novae with short orbital periods and the presence of magnetic white dwarfs. It is suggested that funneling of the accretion flow onto the magnetic poles favors the conditions for a thermonuclear runaway, increasing the frequency of eruptions for magnetic systems.

Dead Star Rumbles

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Composite of Supernova Remnant Cassiopeia A This Spitzer Space Telescope composite shows the supernova remnant Cassiopeia A (white ball) and surrounding clouds of dust (gray, orange and blue). It consists of two processed images taken one year apart. Dust features that have not changed over time appear gray, while those that have changed are colored blue or orange. Blue represents an earlier time and orange, a later time.

These observations illustrate that a blast of light from Cassiopeia A is waltzing outward through the dusty skies. This dance, called an 'infrared echo,' began when the remnant erupted about 50 years ago.

Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion 325 years ago. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. This remnant is located 10,000 light-years away in the northern constellation Cassiopeia.

An infrared echo is created when a star explodes or erupts, flashing light into surrounding clumps of dust. As the light zips through the dust clumps, it heats them up, causing them to glow successively in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. This apparent motion can be seen here by the shift in colored dust clumps.

Echoes are distinct from supernova shockwaves, which are made up material that is swept up and hurled outward by exploding stars.

This infrared echo is the largest ever seen, stretching more than 50 light-years away from Cassiopeia A. If viewed from Earth, the entire movie frame would take up the same amount of space as two full moons.

Hints of an older infrared echo from Cassiopeia A's supernova explosion hundreds of years ago can also be seen.

The earlier Spitzer image was taken on November 30, 2003, and the later, on December 2, 2004.

Infrared spectroscopy of the remnant of Nova Sco 2014: a symbiotic star with too little circumstellar matter to decelerate the ejecta

NASA Astrophysics Data System (ADS)

Munari, U.; Banerjee, D. P. K.

2018-03-01

Pre-outburst 2MASS and WISE photometry of Nova Sco 2014 (V1534 Sco) has suggested the presence of a cool giant at the location of the nova in the sky. The spectral evolution recorded for the nova did not, however, support a direct partnership because no flash-ionized wind and no deceleration of the ejecta were observed, contrary to the behaviour displayed by other novae which erupted within symbiotic binaries like V407 Cyg or RS Oph. We have therefore obtained 0.8-2.5 μm spectra of the remnant of Nova Sco 2014 in order to ascertain if a cool giant is indeed present and if it is physically associated with the nova. The spectrum shows the presence of a M6III giant, reddened by E(B - V) = 1.20, displaying the typical and narrow emission-line spectrum of a symbiotic star, including He I 1.0830 μm with a deep P-Cyg profile. This makes Nova Sco 2014 a new member of the exclusive club of novae that erupt within a symbiotic binary. Nova Sco 2014 shows that a nova erupting within a symbiotic binary does not always come with a deceleration of the ejecta, contrary to the common belief. Many other similar systems may lay hidden in past novae, especially in those that erupted prior to the release of the 2MASS all-sky infrared survey, which could be profitably cross-matched now against them.

Liverpool Telescope Spectroscopy of the Nova Eruption from V392 Persei

NASA Astrophysics Data System (ADS)

Darnley, M. J.; Copperwheat, C. M.; Harvey, E. J.; Healy, M. W.

2018-05-01

Here we report Liverpool Telescope (LT; Steele et al. 2004) spectroscopy of the recent nova eruption (ATel #11588) from the known dwarf nova system V392 Per. A Fermi & gamma;-ray detection of the eruption has also been reported (ATel #11590) along with additional photometry (ATel #11594).

Cepheus

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

(abbrev. Cep, gen. Cephei; area 588 sq. deg.) A northern constellation which lies between Draco and Cassiopeia, and culminates at midnight in late August. It is named after King Cepheus, husband of Queen Cassiopeia and father of Andromeda in Greek mythology. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....

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;

An extensive optical study of V2491 Cyg (Nova Cyg 2008 N.2), from maximum brightness to return to quiescence

NASA Astrophysics Data System (ADS)

Munari, U.; Siviero, A.; Dallaporta, S.; Cherini, G.; Valisa, P.; Tomasella, L.

2011-04-01

The photometric and spectroscopic evolution of the He/N and very fast Nova Cyg 2008 N.2 (V2491 Cyg) is studied in detail. A primary maximum was reached at V = 7.45 ± 0.05 on April 11.37 (±0.1) 2008 UT, followed by a smooth decline characterized by t2V=4.8 days, and then a second maximum was attained at V = 9.49 ± 0.03, 14.5 days after the primary one. This is the only third nova to have displayed a secondary maximum, after V2362 Cyg and V1493 Aql. The development and energetics of the secondary maximum is studied in detail. The smooth decline that followed was accurately monitored until day +144 when the nova was 8.6 mag fainter than maximum brightness, well into its nebular phase, with its line and continuum emissivity declining as t-3. The reddening affecting the nova was EB- V = 0.23 ± 0.01, and the distance of 14 kpc places the nova at a height above the galactic plane of 1.1 kpc, larger than typical for He/N novae. The expansion velocity of the bulk of ejecta was 2000 km/s, with complex emission profiles and weak P-Cyg absorptions during the optically thick phase, and saddle-like profiles during the nebular phase. Photo-ionization analysis of the emission line spectrum indicates that the mass ejected by the outburst was 5.3 × 10 -6 M ⊙ and the mass fractions to be X = 0.573, Y = 0.287, Z = 0.140, with those of individual elements being N = 0.074, O = 0.049, Ne = 0.015. The metallicity of the accreted material was [Fe/H] = -0.25, in line with ambient value at the nova galacto-centric distance. Additional spectroscopic and photometric observations at days +477 and +831 show the nova returned to the brightness level of the progenitor and to have resumed the accretion onto the white dwarf.

The Distance to Nova V959 Mon from VLA Imaging

NASA Astrophysics Data System (ADS)

Linford, J. D.; Ribeiro, V. A. R. M.; Chomiuk, L.; Nelson, T.; Sokoloski, J. L.; Rupen, M. P.; Mukai, K.; O'Brien, T. J.; Mioduszewski, A. J.; Weston, J.

2015-06-01

Determining reliable distances to classical novae is a challenging but crucial step in deriving their ejected masses and explosion energetics. Here we combine radio expansion measurements from the Karl G. Jansky Very Large Array with velocities derived from optical spectra to estimate an expansion parallax for nova V959 Mon, the first nova discovered through its γ-ray emission. We spatially resolve the nova at frequencies of 4.5-36.5 GHz in nine different imaging epochs. The first five epochs cover the expansion of the ejecta from 2012 October to 2013 January, while the final four epochs span 2014 February-May. These observations correspond to days 126 through 199 and days 615 through 703 after the first detection of the nova. The images clearly show a non-spherical ejecta geometry. Utilizing ejecta velocities derived from three-dimensional modeling of optical spectroscopy, the radio expansion implies a distance between 0.9 ± 0.2 and 2.2 ± 0.4 kpc, with a most probable distance of 1.4 ± 0.4 kpc. This distance implies a γ-ray luminosity of 0.6× {{10}35} erg s-1, which is much less than the prototype γ-ray-detected nova, V407 Cyg, possibly due to the lack of a red giant companion in the V959 Mon system. V959 Mon also has a much lower γ-ray luminosity than other classical novae detected in γ-rays to date, indicating a range of at least a factor of 10 in the γ-ray luminosities for these explosions.

On the interpretation and implications of nova abundances: An abundance of riches or an overabundance of enrichments

NASA Technical Reports Server (NTRS)

Livio, Mario; Truran, James W.

1994-01-01

We reexamine the question of the frequency of occurrence of oxygen-neon-magnesium (ONeMg) degenerate dwarfs in classical nova systems, in light of recent observations which have been interpreted as suggesting that 'neon novae' can be associated with relatively low mass white dwarfs. Determinations of heavy-element concentrations in nova ejecta are reviewed, and possible interpretations of their origin are examined. We conclude that, of the 18 classical novae for which detailed abundance analyses are availble, only two (or possibly three) seem unambiguously to demand the presence of an underlying ONeMg white dwarf: V693 CrA 1981, V1370 Aql 1982, and possibly QU Vul 1984. Three other novae which exhibit significant neon enrichments, relative to their total heavy-element concentrations, are RR Pic 1925, V977, Sco 1989, and LMC 1990 No. 1. This result is entirely consistent with present frequency estimates, and our interpretation of the lower levels of enrichment in other systems explains, in a natural way, the existence of relatively low mass white dwarfs in some of the 'neon' novae.

A Light-curve Analysis of Gamma-Ray Nova V959 Mon: Distance and White Dwarf Mass

NASA Astrophysics Data System (ADS)

Hachisu, Izumi; Kato, Mariko

2018-05-01

V959 Mon is a nova detected in gamma-rays. It was discovered optically about 50 days after the gamma-ray detection owing to its proximity to the Sun. The nova’s speed class is unknown because of the lack of the earlier half of its optical light curve and a short supersoft X-ray phase due to eclipse by the disk rim. Using the universal decline law and time-stretching method, we analyzed the data on V959 Mon and obtained nova parameters. We estimated the distance modulus in the V band to be (m ‑ M) V = 13.15 ± 0.3 for the reddening of E(B ‑ V) = 0.38 ± 0.01 by directly comparing it with novae of a similar type—LV Vul, V1668 Cyg, IV Cep, and V1065 Cen. The distance to V959 Mon is 2.5 ± 0.5 kpc. If we assume that the early phase of the light curve of V959 Mon is the same as that of time-stretched light curves of LV Vul, our model fitting of the light curve suggests that the white dwarf (WD) mass is 0.9–1.15 M ⊙, which is consistent with a neon nova identification. At the time of gamma-ray detection the photosphere of the nova envelope extends to 5–8 R ⊙ (about two or three times the binary separation) and the wind mass-loss rate is (3{--}4)× {10}-5 {M}ȯ yr‑1. The period of hard X-ray emission is consistent with the time of appearance of the companion star from the nova envelope. The short supersoft X-ray turnoff time is consistent with the epoch when the WD photosphere shrank to behind the rising disk rim, which occurred 500 days before nuclear burning turned off.

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.

Polarimetry and spectroscopy of the "oxygen flaring" DQ Herculis-like nova: V5668 Sagittarii (2015)

NASA Astrophysics Data System (ADS)

Harvey, E. J.; Redman, M. P.; Darnley, M. J.; Williams, S. C.; Berdyugin, A.; Piirola, V. E.; Fitzgerald, K. P.; O'Connor, E. G. P.

2018-03-01

Context. Classical novae are eruptions on the surface of a white dwarf in a binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell of gas and dust around the system. The three-dimensional structure of these shells is difficult to untangle when viewed on the plane of the sky. In this work a geometrical model is developed to explain new observations of the 2015 nova V5668 Sagittarii. Aim. We aim to better understand the early evolution of classical nova shells in the context of the relationship between polarisation, photometry, and spectroscopy in the optical regime. To understand the ionisation structure in terms of the nova shell morphology and estimate the emission distribution directly following the light curve's dust-dip. Methods: High-cadence optical polarimetry and spectroscopy observations of a nova are presented. The ejecta is modelled in terms of morpho-kinematics and photoionisation structure. Results: Initially observational results are presented, including broadband polarimetry and spectroscopy of V5668 Sgr nova during eruption. Variability over these observations provides clues towards the evolving structure of the nova shell. The position angle of the shell is derived from polarimetry, which is attributed to scattering from small dust grains. Shocks in the nova outflow are suggested in the photometry and the effect of these on the nova shell are illustrated with various physical diagnostics. Changes in density and temperature as the super soft source phase of the nova began are discussed. Gas densities are found to be of the order of 109 cm-3 for the nova in its auroral phase. The blackbody temperature of the central stellar system is estimated to be around 2.2 × 105 K at times coincident with the super soft source turn-on. It was found that the blend around 4640 Å commonly called "nitrogen flaring" is more naturally explained as flaring of the O II multiplet (V1) from 4638-4696 Å, i.e. "oxygen flaring". Conclusions: V5668 Sgr (2015) was a remarkable nova of the DQ Her class. Changes in absolute polarimetric and spectroscopic multi-epoch observations lead to interpretations of physical characteristics of the nova's evolving outflow. The high densities that were found early-on combined with knowledge of the system's behaviour at other wavelengths and polarimetric measurements strongly suggest that the visual "cusps" are due to radiative shocks between fast and slow ejecta that destroy and create dust seed nuclei cyclically.

Suzaku Observation of the Dwarf Nova V893 Scorpii: The Discovery of a Partial X-Ray Eclipse

NASA Technical Reports Server (NTRS)

Mukai, Koji; Zietsman, E.; Still, M.

2008-01-01

V893 Sco is an eclipsing dwarf nova that had attracted little attention from X-ray astronomers until it was proposed as the identification of an RXTE all-sky slew survey (XSS) source. Here we report on the po inted X-ray observations of this object using Suzaku. We confirm V893 Sco to be X-ray bright, whose spectrum is highly absorbed for a dwar f nova. We have also discovered a partial X-ray eclipse in V893 Sco. This is the first time that a partial eclipse is seen in Xray light c urves of a dwarf nova. We have successfully modeled the gross features of the optical and X-ray eclipse light curves using a boundary layer geometry of the X-ray emission region. Future observations may lead to confirmation of this basic picture, and allow us to place tight co nstraints on the size of the X-ray emission region. The partial X-ray eclipse therefore should make V893 Sco a key object in understanding the physics of accretion in quiescent dwarf nova.

ORIGINS OF ABSORPTION SYSTEMS OF CLASSICAL NOVA V2659 CYG (NOVA CYG 2014)

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2016-10-10

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{sup −1}, and −1100 to −1500 km s{sup −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,more » 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.« less

Very high-energy γ -ray observations of novae and dwarf novae with the MAGIC telescopes

DOE PAGES

Ahnen, M. L.

2015-10-01

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.

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.

X-ray spectrum of Cassiopeia A measured with the Einstein SSS. [Solid State Spectrometer

NASA Technical Reports Server (NTRS)

Becker, R. H.; Smith, B. W.; White, N. E.; Holt, S. S.; Boldt, E. A.; Mushotzky, R. F.; Serlemitsos, P. J.

1979-01-01

The solid state spectrometer (SSS) on the Einstein Observatory observed the X-ray spectrum of Cas A between 0.8 and 4.5 keV with a FWHM energy resolution of 160 eV. Line emission consistent with transitions of helium-like ions of Si, S, and Ar was well defined. Comparison between the data and the emission expected from a gas containing two distinct thermal components requires additional line emission from Mg, Al, Ca, and Fe. These results are discussed in the context of both equilibrium and nonequilibrium situations.

Impacts of the Detection of Cassiopeia A Point Source.

PubMed

Umeda; Nomoto; Tsuruta; Mineshige

2000-05-10

Very recently the Chandra first light observation discovered a point-like source in the Cassiopeia A supernova remnant. This detection was subsequently confirmed by the analyses of the archival data from both ROSAT and Einstein observations. Here we compare the results from these observations with the scenarios involving both black holes (BHs) and neutron stars (NSs). If this point source is a BH, we offer as a promising model a disk-corona type model with a low accretion rate in which a soft photon source at approximately 0.1 keV is Comptonized by higher energy electrons in the corona. If it is an NS, the dominant radiation observed by Chandra most likely originates from smaller, hotter regions of the stellar surface, but we argue that it is still worthwhile to compare the cooler component from the rest of the surface with cooling theories. We emphasize that the detection of this point source itself should potentially provide enormous impacts on the theories of supernova explosion, progenitor scenario, compact remnant formation, accretion to compact objects, and NS thermal evolution.

Deepest Image of Exploded Star Uncovers Bipolar Jets

NASA Astrophysics Data System (ADS)

2004-08-01

A spectacular new image of Cassiopeia A from NASA's Chandra X-ray Observatory released today has nearly 200 times more data than the "First Light" Chandra image of this object made five years ago. The new image reveals clues that the initial explosion caused by the collapse of a massive star was far more complicated than suspected. Chandra Broadband Image of Cassiopeia A Chandra Broadband Image of Cassiopeia A "Although this young supernova remnant has been intensely studied for years, this deep observation is the most detailed ever made of the remains of an exploded star," said Martin Laming of the Naval Research Laboratory in Washington, D.C. Laming is part of a team of scientists led by Una Hwang of the Goddard Space Flight Center in Greenbelt, Maryland. "It is a gold mine of data that astronomers will be panning through for years to come." The one-million-second (about 11.5-day) observation of Cassiopeia A uncovered two large, opposed jet-like structures that extend to about 10 light years from the center of the remnant. Clouds of iron that have remained nearly pure for the approximately 340 years since the explosion were also detected. "The presence of the bipolar jets suggests that jets could be more common in relatively normal supernova explosions than supposed by astronomers," said Hwang. A paper by Hwang, Laming and others on the Cassiopeia A observation will appear in an upcoming issue of The Astrophysical Journal Letters. Chandra Enhanced Silicon Image of Cassiopeia A Chandra Enhanced Silicon Image of Cassiopeia A X-ray spectra show that the jets are rich in silicon atoms and relatively poor in iron atoms. In contrast, fingers of almost pure iron gas extend in a direction nearly perpendicular to the jets. This iron was produced in the central, hottest regions of the star. The high silicon and low iron abundances in the jets indicate that massive, matter-dominated jets were not the immediate cause of the explosion, as these should have carried out large quantities of iron from the central regions of the star. A working hypothesis is that the explosion produced high-speed jets similar to those in hypernovae that produce gamma-ray bursts, but in this case, with much lower energies. The explosion also left a faint neutron star at the center of the remnant. Unlike the rapidly rotating neutron stars in the Crab Nebula and Vela supernova remnants that are surrounded by dynamic magnetized clouds of electrons, this neutron star is quiet and faint. Nor has pulsed radiation been detected from it. It may have a very strong magnetic field generated during the explosion that helped to accelerate the jets, and today resembles other strong-field neutron stars (a.k.a. "magnetars") in lacking a wind nebula. Chandra 3-color X-ray Image of Cassiopeia A Chandra 3-color X-ray Image of Cassiopeia A Chandra was launched aboard the Space Shuttle Columbia on July 23, 1999. Less than a month later, it was able to start taking science measurements along with its calibration data. The original Cassiopeia A observation was taken on August 19, 1999, and then released to the scientific community and the public one week later on August 26. At launch, Chandra's original mission was intended to be five years. Having successfully completed that objective, NASA announced last August that the mission would be extended for another five years. The data for this new Cassiopeia A image were obtained by Chandra's Advanced Charged Coupled Device Imaging Spectrometer (ACIS) instrument during the first half of 2004. Due to its value to the astronomical community, this rich dataset was made available immediately to the public. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA's Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

First optical candidate for a recovered classical nova in a globular cluster - Nova 1938 in M14

NASA Technical Reports Server (NTRS)

Shara, Michael M.; Potter, Michael; Moffat, Anthony F. J.; Hogg, Helen S.; Wehlau, Amelia

1986-01-01

U, B, V, R, and H-alpha CCD frames of the field of the nova which appeared in the globular cluster M14 in 1938 have been compared with the nova discovery images. On the basis of positional coincidence, brightness, and blue color, a candidate nova was identified and its right ascension and declination to within 1 arcsec each. Confirmation of the candidate and detailed study of the quiescent nova will probably require Hubble Space Telescope observations.

Expanded Very Large Array Nova Project Observations of the Classical Nova V1723 Aquilae

NASA Astrophysics Data System (ADS)

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.; O'Brien, T. J.

2011-09-01

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

Discovery of Rapidly Moving Partial X-Ray Absorbers Within Cassiopeiae

NASA Technical Reports Server (NTRS)

Hamaguchi, K.; Oskinova, L.; Russell, C. M. P.; Petre, R.; Enoto, T.; Morihana, K.; Ishida, M.

2016-01-01

Gamma Cassiopeiae is an enigmatic Be star with unusually strong hard X-ray emission. The Suzaku observatory detected six rapid X-ray spectral hardening events called "softness dips" in a approx.100 ks observation in 2011. All the softness dip events show symmetric softness-ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either approx.40% or approx.70% partial covering absorption to kT approx.12 keV plasma emission by matter with a neutral hydrogen column density of approx.(2-8) ×10(exp 21)/sq cm, while the spectrum outside these dips is almost free of absorption. This result suggests the presence of two distinct X-ray-emitting spots in the gamma Cas system, perhaps on a white dwarf (WD) companion with dipole mass accretion. The partial covering absorbers may be blobs in the Be stellar wind, the Be disk, or rotating around the WD companion. Weak correlations of the softness ratios to the hard X-ray flux suggest the presence of stable plasmas at kT approx 0.9 and 5 keV, which may originate from the Be or WD winds. The formation of a Be star and WD binary system requires mass transfer between two stars; gamma Cas may have experienced such activity in the past.

Early X- and HE γ-ray emission from the symbiotic recurrent novae V745 Sco & RS Oph.

NASA Astrophysics Data System (ADS)

Delgado, L.; Hernanz, M.

2017-10-01

RS Oph was the first nova for which evidence of particle acceleration during its 2006 outburst was found. In recent years, several nova explosions - eight classical and two symbiotic recurrent novae - have been detected by Fermi/LAT at E>100 MeV. In most cases, this emission has been observed early after the explosion, around the optical maximum, and for a short period of time. The high-energy γ-ray emission is a consequence of π^{0} decay and/or Inverse Compton, which are related to particle (p and e^{-}) acceleration in the strong shock between the nova ejecta and the circumstellar matter. Our aim is to understand the acceleration process through the analysis of contemporaneous X-ray emission, and in particular, through the evolution of the shock wave. A deep analysis of early X-ray observations of the symbiotic recurrent novae V745 Sco (2014) by Swift/XRT, Chandra/HETG and NuStar, and RS Oph (2006) by XMM-Newton/EPIC and RGS, Swift/XRT and BAT and RXTE/PCA is presented taking into account the contemporaneous information from the IR and radio observations. This provides for the first time a global view of the early evolution of a nova remnant and its relationship with particle acceleration.

Beryllium detection in the very fast nova ASASSN-16kt (V407 Lupi)

NASA Astrophysics Data System (ADS)

Izzo, L.; Molaro, P.; Bonifacio, P.; Della Valle, M.; Cano, Z.; de Ugarte Postigo, A.; Prieto, J. L.; Thöne, C.; Vanzi, L.; Zapata, A.; Fernandez, D.

2018-02-01

We present high-resolution spectroscopic observations of the fast nova ASASSN-16kt (V407 Lup). A close inspection of spectra obtained at early stages has revealed the presence of low-ionization lines, and among the others we have identified the presence of the ionised 7Be doublet in a region relatively free from possible contaminants. After studying their intensities, we have inferred that ASASSN-16kt has produced (5.9 - 7.7)× 10-9 M⊙ of 7Be. The identification of bright Ne lines may suggest that the nova progenitor is a massive (1.2 M⊙) oxygen-neon white dwarf. The high outburst frequency of oxygen-neon novae implies that they likely produce an amount of Be similar, if not larger, to that produced by carbon-oxygen novae, then confirming that classical novae are among the main factories of lithium in the Galaxy.

Gamma-ray emission from internal shocks in novae

NASA Astrophysics Data System (ADS)

Martin, P.; Dubus, G.; Jean, P.; Tatischeff, V.; Dosne, C.

2018-04-01

Context. Gamma-ray emission at energies ≥100 MeV has been detected from nine novae using the Fermi Large Area Telescope (LAT), and can be explained by particle acceleration at shocks in these systems. Eight out of these nine objects are classical novae in which interaction of the ejecta with a tenuous circumbinary material is not expected to generate detectable gamma-ray emission. Aim. We examine whether particle acceleration at internal shocks can account for the gamma-ray emission from these novae. The shocks result from the interaction of a fast wind radiatively-driven by nuclear burning on the white dwarf with material ejected in the initial runaway stage of the nova outburst. Methods: We present a one-dimensional model for the dynamics of a forward and reverse shock system in a nova ejecta, and for the associated time-dependent particle acceleration and high-energy gamma-ray emission. Non-thermal proton and electron spectra are calculated by solving a time-dependent transport equation for particle injection, acceleration, losses, and escape from the shock region. The predicted emission is compared to LAT observations of V407 Cyg, V1324 Sco, V959 Mon, V339 Del, V1369 Cen, and V5668 Sgr. Results: The ≥100 MeV gamma-ray emission arises predominantly from particles accelerated up to 100 GeV at the reverse shock and undergoing hadronic interactions in the dense cooling layer downstream of the shock. The emission rises within days after the onset of the wind, quickly reaches a maximum, and its subsequent decrease reflects mostly the time evolution of the wind properties. Comparison to gamma-ray data points to a typical scenario where an ejecta of mass 10-5-10-4 M⊙ expands in a homologous way with a maximum velocity of 1000-2000 km s-1, followed within a day by a wind with a velocity <2000 km s-1 and a mass-loss rate of 10-4-10-3 M⊙ yr-1 declining over a time scale of a few days. Because of the large uncertainties in the measurements, many parameters of the problem are degenerate and/or poorly constrained except for the wind velocity, the relatively low values of which result in the majority of best-fit models having gamma-ray spectra with a high-energy turnover below 10 GeV. Our typical model is able to account for the main features in the observations of the recent gamma-ray nova ASASSN-16ma. Conclusions: The internal shock model can account for the gamma-ray emission of the novae detected by Fermi LAT. Gamma-ray observations hold potential for probing the mechanism of mass ejection in novae, but should be combined to diagnostics of the thermal emission at lower energies to be more constraining.

Identifying and quantifying recurrent novae masquerading as classical novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pagnotta, Ashley; Schaefer, Bradley E., E-mail: pagnotta@amnh.org

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 CNemore » 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.« less

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

NASA Astrophysics Data System (ADS)

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

2010-11-01

We present light curves of three classical novae (CNe; KT Eridani, V598 Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) derived from data obtained by the Solar Mass Ejection Imager (SMEI) on board the Coriolis satellite. SMEI provides near complete skymap coverage with precision visible-light photometry at 102 minute cadence. The light curves derived from these skymaps offer unprecedented temporal resolution around, and especially before, maximum light, a phase of the eruption normally not covered by ground-based observations. They allow us to explore fundamental parameters of individual objects including the epoch of the initial explosion, the reality and duration of any pre-maximum halt (found in all three fast novae in our sample), the presence of secondary maxima, speed of decline of the initial light curve, plus precise timing of the onset of dust formation (in V1280 Sco) leading to estimation of the bolometric luminosity, white dwarf mass, and object distance. For KT Eri, Liverpool Telescope SkyCamT data confirm important features of the SMEI light curve and overall our results add weight to the proposed similarities of this object to recurrent rather than to CNe. In RS Oph, comparison with hard X-ray data from the 2006 outburst implies that the onset of the outburst coincides with extensive high-velocity mass loss. It is also noted that two of the four novae we have detected (V598 Pup and KT Eri) were only discovered by ground-based observers weeks or months after maximum light, yet these novae reached peak magnitudes of 3.46 and 5.42, respectively. This emphasizes the fact that many bright novae per year are still overlooked, particularly those of the very fast speed class. Coupled with its ability to observe novae in detail even when relatively close to the Sun in the sky, we estimate that as many as five novae per year may be detectable by SMEI.

Photometric evolution of seven recent novae and the double-component characterizing the light curve of those emitting in gamma rays

NASA Astrophysics Data System (ADS)

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

2017-08-01

The BVI light curves of seven recent novae (I.e. V1534 Sco, V1535 Sco, V2949 Oph, V3661 Oph, MASTER OT J010603.18-744715.8, TCP J1734475-240942 and ASASSN-16ma) have been extensively mapped with daily robotic observations from Atacama (Chile): five belong to the Galactic bulge, one to the Small Magellanic Cloud and another is a Galactic disc object. The two programme novae detected in γ-rays by Fermi-LAT (I.e. TCP J1734475-240942 and ASASSN-16ma) are bulge objects with unevolved companions. They distinguish themselves by showing a double-component optical light curve. The first component to develop is the fireball from freely expanding, ballistic-launched ejecta, with a time of passage through maximum that is strongly dependent on wavelength (˜1 d delay between the B and I bands). The second component, emerging simultaneously with the nova detection in γ-rays, evolves at a slower pace, its optical brightness being proportional to the γ-ray flux, and its passage through maximum not dependent on wavelength. The fact that γ-rays are detected at a flux level that differs by four times from novae at the distance of the bulge seems to suggest that γ-ray emission is not a widespread property of normal novae. We discuss the advantages offered by high-quality photometric observations collected with only one telescope (as opposed to data provided by a number of different instruments). We also observe the effects of the wavelength dependence of fireball expansion, the recombination in the flashed wind of a giant companion, the subtle presence of hiccups and plateaus, and the super-soft X-ray emission and its switch-off. Four programme novae (V2949 Oph, V3661 Oph, TCP J18102829-2729590 and ASASSN-16ma) have normal dwarf companions: V1534 Sco contains an M3 III giant, V1535 Sco a K-type giant and MASTER OT J010603.18-744715.8 a subgiant. We also comment briefly on the maximum absolute magnitude relation with decline time (MMRD).

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.

Iron line emission from a high temperature plasma in Cas A

NASA Technical Reports Server (NTRS)

Pravdo, S. H.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Rothschild, R. E.; Serlemitsos, P. J.; Swank, J. H.

1976-01-01

The X-ray spectrum of Cassiopeia A was observed for several days by the proportional counter experiment on board OSO-8. The high energy ( 5 keV) data are fit well by a thermal spectrum. A narrow iron line which is predicted by the thermal model is also observed. The low energy (2-5 keV) data show an excess over the high temperature component which is consistent with the presence of an additional low temperature thermal component. Iron abundance in the source relative to normal cosmic abundance is discussed, as in the relation of this observation to shock wave and multi-component thermal models for supernova remnants.

A UNIVERSAL DECLINE LAW OF CLASSICAL NOVAE. IV. V838 HER (1991): A VERY MASSIVE WHITE DWARF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Mariko; Hachisu, Izumi; Cassatella, Angelo, E-mail: mariko@educ.cc.keio.ac.j, E-mail: hachisu@ea.c.u-tokyo.ac.j, E-mail: cassatella@fis.uniroma3.i

2009-10-20

We present a unified model of optical and ultraviolet (UV) light curves for one of the fastest classical novae, V838 Herculis (Nova Herculis 1991), and estimate its white dwarf (WD) mass. Based on an optically thick wind theory of nova outbursts, we model the optical light curves with free-free emission and the UV 1455 A light curves with blackbody emission. Our models of 1.35 +- 0.02 M {sub sun} WD simultaneously reproduce the optical and UV 1455 A observations. The mass lost by the wind is DELTAM {sub wind} approx 2 x 10{sup -6} M {sub sun}. We provide newmore » determinations of the reddening, E(B - V) = 0.53 +- 0.05, and of the distance, 2.7 +- 0.5 kpc.« less

Direct measurement of astrophysically important resonances in 38K(p ,γ )39Ca

NASA Astrophysics Data System (ADS)

Christian, G.; Lotay, G.; Ruiz, C.; Akers, C.; Burke, D. S.; Catford, W. N.; Chen, A. A.; Connolly, D.; Davids, B.; Fallis, J.; Hager, U.; Hutcheon, D.; Mahl, A.; Rojas, A.; Sun, X.

2018-02-01

Background: Classical novae are cataclysmic nuclear explosions occurring when a white dwarf in a binary system accretes hydrogen-rich material from its companion star. Novae are partially responsible for the galactic synthesis of a variety of nuclides up to the calcium (A ˜40 ) region of the nuclear chart. Although the structure and dynamics of novae are thought to be relatively well understood, the predicted abundances of elements near the nucleosynthesis endpoint, in particular Ar and Ca, appear to sometimes be in disagreement with astronomical observations of the spectra of nova ejecta. Purpose: One possible source of the discrepancies between model predictions and astronomical observations is nuclear reaction data. Most reaction rates near the nova endpoint are estimated only from statistical model calculations, which carry large uncertainties. For certain key reactions, these rate uncertainties translate into large uncertainties in nucleosynthesis predictions. In particular, the 38K(" close=")p ,γ )">p ,γ 39Ca reaction has been identified as having a significant influence on Ar, K, and Ca production. In order to constrain the rate of this reaction, we have performed a direct measurement of the strengths of three candidate ℓ =0 resonances within the Gamow window for nova burning, at 386 ±10 keV, 515 ±10 keV, and 689 ±10 keV. Method: The experiment was performed in inverse kinematics using a beam of unstable 38K impinged on a windowless hydrogen gas target. The 39Ca recoils and prompt γ rays from 38K, 39Ca reactions were detected in coincidence using a recoil mass separator and a bismuth-germanate scintillator array, respectively. Results: For the 689 keV resonance, we observed a clear recoil-γ coincidence signal and extracted resonance strength and energy values of 120-30+50(stat.)-60 +20(sys .) meV and 679-1+2(stat .) ±1 (sys .) keV , respectively. We also performed a singles analysis of the recoil data alone, extracting a resonance strength of 120 ±20 (stat .)±15 (sys .) meV, consistent with the coincidence result. For the 386 keV and 515 keV resonances, we extract 90 % confidence level upper limits of 2.54 meV and 18.4 meV, respectively. Conclusions: We have established a new recommended 38K(p ,γ ) 39Ca rate based on experimental information, which reduces overall uncertainties near the peak temperatures of nova burning by a factor of ˜250 . Using the rate obtained in this work in model calculations of the hottest oxygen-neon novae reduces overall uncertainties on Ar, K, and Ca synthesis to factors of 15 or less in all cases.

Optical and Near-infrared Study of Nova V2676 Oph 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raj, A.; Das, R. K.; Walter, F. M., E-mail: ashish.raj@iiap.res.in

2017-02-01

We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H i lines from the Balmer series, Fe ii, N i, and [O i] lines in the initial days, typical of an Fe ii type nova. The measured FWHM for the H β and H α lines was 800–1200 km s{sup −1}. There wasmore » pronounced dust formation starting 90 days after the outburst. The J − K color was the largest among recent dust-forming novae.« less

Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni.

PubMed

Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bouvier, A; Brandt, T J; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Carrigan, S; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Corbel, S; Corbet, R; DeCesar, M E; den Hartog, P R; Dermer, C D; de Palma, F; Digel, S W; Donato, D; do Couto e Silva, E; Drell, P S; Dubois, R; Dubus, G; Dumora, D; Favuzzi, C; Fegan, S J; Ferrara, E C; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Harding, A K; Hayashida, M; Hays, E; Healey, S E; Hill, A B; Horan, D; Hughes, R E; Itoh, R; Jean, P; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Koerding, E; Kuss, M; Lande, J; Latronico, L; Lee, S-H; Lemoine-Goumard, M; Garde, M Llena; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Makeev, A; Mazziotta, M N; McConville, W; McEnery, J E; Mehault, J; Michelson, P F; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Naumann-Godo, M; Nestoras, I; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ray, P S; Razzano, M; Razzaque, S; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ripken, J; Ritz, S; Romani, R W; Roth, M; Sadrozinski, H F-W; Sander, A; Parkinson, P M Saz; Scargle, J D; Schinzel, F K; Sgrò, C; Shaw, M S; Siskind, E J; Smith, D A; Smith, P D; Sokolovsky, K V; Spandre, G; Spinelli, P; Stawarz, Ł; Strickman, M S; Suson, D J; Takahashi, H; Takahashi, T; Tanaka, T; Tanaka, Y; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Winer, B L; Wolff, M T; Wood, K S; Yang, Z; Ylinen, T; Ziegler, M; Maehara, H; Nishiyama, K; Kabashima, F; Bach, U; Bower, G C; Falcone, A; Forster, J R; Henden, A; Kawabata, K S; Koubsky, P; Mukai, K; Nelson, T; Oates, S R; Sakimoto, K; Sasada, M; Shenavrin, V I; Shore, S N; Skinner, G K; Sokoloski, J; Stroh, M; Tatarnikov, A M; Uemura, M; Wahlgren, G M; Yamanaka, M

2010-08-13

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

Early VLA and AMI-LA Radio Detections of the Nova V392 Per

NASA Astrophysics Data System (ADS)

Linford, J. D.; Bright, J.; Chomiuk, L.; Fender, R.; van der Horst, A.; Mioduszewski, A.; Sokoloski, J.; Rupen, M.; Nelson, T.; Mukai, K.

2018-05-01

We report radio observations of the young nova V392 Per (ATel #11588, ATel #11590, ATel #11601, ATel #11605, and ATel #11617) with the Karl G. Janksy Very Large Array (VLA) and the Arcminute Microkelvin Imager Large Array (AMI-LA).

Chandra X-Ray Observatory Image of Cassiopeia A

NASA Technical Reports Server (NTRS)

1999-01-01

This is an extraordinary first image from the Chandra X-Ray Observatory (CXO), the supernova remnant Cassiopeia A, tracing the aftermath of a gigantic stellar explosion in such sturning detail that scientists can see evidence of what may be a neutron star or black hole near the center. The red, green, and blue regions in this image of the supernova remnant Cassiopeia A show where the intensity of low, medium, and high energy X-rays, respectively, is greatest. The red material on the left outer edge is enriched in iron, whereas the bright greenish white region on the low left is enriched in silicon and sulfur. In the blue region on the right edge, low and medium energy X-rays have been filtered out by a cloud of dust and gas in the remnant . The image was made with the CXO's Advanced Charged-Coupled Device (CCD) Imaging Spectrometer (ACIS). Photo credit: NASA/CXC/SAO/Rutgers/J.Hughes

Dance of the Light Echoes

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for larger poster version

This composite image from NASA's Spitzer Space Telescope shows the remnant of a star that exploded, called Cassiopeia A (center) and its surrounding 'light echoes' -- dances of light through dusty clouds, created when stars blast apart. The light echoes are colored and the surrounding clouds of dust are gray.

In figure 1, dramatic changes are highlighted in phenomena referred to as light echoes (colored areas) around the Cassiopeia A supernova remnant (center). Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died.

A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light. In figure 1, this apparent motion can be seen here by the shift in colored dust clumps

Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died. This remnant is located 11,000 light-years away in the northern constellation Cassiopeia.

This composite consists of six processed images taken over a time span of three years. Dust features that have not changed over time appear gray, while those that have changed are colored blue or orange. Bluer colors represent an earlier time and redder ones, a later time. The progression of the light echo through the dust can be seen here by the shift in colored dust clumps.

This light echo is the largest ever seen, stretching more than 300 light-years away from Cassiopeia A. If viewed from Earth, the entire frame would take up the same amount of space as seven full moons. The supernova remnant is located 11,000 light-years away in the northern constellation Cassiopeia.

The earliest Spitzer image shown here was taken in February 2005, and the latest one in January 2008. The image was processed to emphasize the light echo by enhancing the areas that change, which appear in color, and dimming regions that remain constant, seen in grayscale. Spurious color artifacts such as diffraction spikes around stars were removed by hand.

VERITAS Observations of the Nova in V407 Cygni

NASA Technical Reports Server (NTRS)

Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.;

An X-ray survey of nine historical novae. [HEAO 2 observations

NASA Technical Reports Server (NTRS)

Becker, R. H.; Marshall, F. E.

1980-01-01

The Einstein Observatory imaging proportional counter was used to search for X-ray emission from nine nearby historical novae. Six of the novae were detected with estimated X-ray intensities between .1 to 4 keV of 10 to the -13th power to 10 to the -11th power ergs/sq cm-s, comparable to the intensities of previously detected cataclysmic variables. The X-ray intensity of one of the novae, V603 Aql, varies over times of several hundred seconds. The data suggest a correlation between the decay rate of the historical outburst and the current X-ray luminosity. Alternatively, the X-ray luminosity may be related to the inclination of the binary system.

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.

Isospin mixing reveals 30P(p, γ) 31S resonance influencing nova nucleosynthesis

DOE PAGES

Bennett, M. B.; Wrede, C.; Brown, B. A.; ...

2016-03-08

Here, the thermonuclear 30P(p, γ) 31S reaction rate is critical for modeling the final elemental and isotopic abundances of ONe nova nucleosynthesis, which affect the calibration of proposed nova thermometers and the identification of presolar nova grains, respectively. Unfortunately, the rate of this reaction is essentially unconstrained experimentally, because the strengths of key 31S proton capture resonance states are not known, largely due to uncertainties in their spins and parities. Using the β decay of 31Cl, we have observed the β-delayed γ decay of a 31S state at E x = 6390.2(7) keV, with a 30P(p, γ) 31S resonance energymore » of E r = 259.3(8) keV, in the middle of the 30P(p, γ) 31S Gamow window for peak nova temperatures. This state exhibits isospin mixing with the nearby isobaric analog state at E x = 6279.0(6) keV, giving it an unambiguous spin and parity of 3/2 + and making it an important l = 0 resonance for proton capture on 30P.« less

Optical evolution of Nova Ophiuchi 2007 = V2615 Oph

NASA Astrophysics Data System (ADS)

Munari, U.; Henden, A.; Valentini, M.; Siviero, A.; Dallaporta, S.; Ochner, P.; Tomasoni, S.

2008-06-01

The moderately fast Nova Oph 2007 reached maximum brightness on 2007 March 28 at V= 8.52, B-V=+1.12, V-RC=+0.76, V-IC=+1.59 and RC-IC=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were tV2= 26.5, tB2= 30, tV3= 48.5 and tB3= 56.5 d. The distance to the nova is d= 3.7 ± 0.2 kpc, the height above the Galactic plane is z= 215 pc, the reddening is E(B-V) = 0.90 and the absolute magnitude at maximum is MmaxV=-7.2 and MmaxB=-7.0. The spectrum four days before maximum resembled a F6 supergiant, in an agreement with broad-band colours. It later developed into that of a standard `Fe ii'-class nova. Nine days past maximum, the expansion velocity estimated from the width of Hα emission component was ˜730 km s-1, and the displacement from it of the principal and diffuse-enhanced absorption systems was ˜650 and 1380 km s-1, respectively. Dust probably formed and disappeared during the period from 82 to 100 d past maximum, causing (at peak dust concentration) an extinction of ΔB= 1.8 mag and an extra ΔE(B-V) = 0.44 reddening.

Modeling SOFIA/FORCAST spectra of the classical nova V5568 Sgr with 3D pyCloudy

NASA Astrophysics Data System (ADS)

Calvén, Emilia; Helton, L. Andrew; Sankrit, Ravi

2017-06-01

We present our first results modelling Nova V5668 Sgr using the pseudo-3D photoionization code pyCloudy (Morisset 2013). V5668 Sgr is a classical nova of the FeII class (Williams et al. 2015; Seach 2015) showing signs of a bipolar flow (Banerjee et al. 2015). We construct a grid of models, which use hour-glass morphologies and a range of C, N, O and Ne abundances, to fit a suite of spectroscopic data in the near and mid-IR obtained between 82 to 556 days after outburst. The spectra were obtained using the FORCAST mid-IR instrument onboard the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) and the 1.2m near-IR telescope of the Mount Abu Infrared Observatory. Additional photometric data from FORCAST, The STONY BROOK/SMARTS Atlas of (mostly) Southern Novae (Walter et al., 2012) and the American Association of Variable Star Observers (AAVSO) were used to supplement the spectral data to obtain the SED of the nova at different times during its evolution. The work presented here is the initial step towards developing a large database of 1D and 3D models that may be used to derive the elemental abundances and dust properties of classical novae.

New {sup 34}Cl proton-threshold states and the thermonuclear {sup 33}S(p,{gamma}){sup 34}Cl rate in ONe novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parikh, A.; Faestermann, T.; Kruecken, R.

2009-07-15

Analysis of presolar grains in primitive meteorites has shown isotopic ratios largely characteristic of the conditions thought to prevail in various astrophysical environments. A possible indicator for a grain of ONe nova origin is a large {sup 33}S abundance: nucleosynthesis calculations predict as much as 150 times the solar abundance of {sup 33}S in the ejecta of nova explosions on massive ONe white dwarfs. This overproduction factor may, however, vary by factors of at least 0.01-3 because of uncertainties of several orders of magnitude in the {sup 33}S(p,{gamma}){sup 34}Cl reaction rate at nova peak temperatures (T{sub peak}{approx}0.1-0.4 GK). These uncertaintiesmore » arise due to the lack of nuclear physics information for states within {approx}600 keV of the {sup 33}S+p threshold in {sup 34}Cl (S{sub p}({sup 34}Cl) = 5143 keV). To better constrain this rate we have measured, for the first time, the {sup 34}S({sup 3}He,t){sup 34}Cl reaction over the region E{sub x}({sup 34}Cl) = 4.9-6 MeV. We confirm previous states and find 15 new states in this energy region. New {sup 33}S(p,{gamma}){sup 34}Cl resonances at E{sub R}=281(2), 301(2), and 342(2) keV may dominate this rate at relevant nova temperatures. Our results could affect predictions of sulphur isotopic ratios in nova ejecta (e.g., {sup 32}S/{sup 33}S) that may be used as diagnostic tools for the nova paternity of grains.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Nicolas F.; Ibata, Rodrigo A.; Chambers, Kenneth C.

We present Keck II/DEIMOS spectroscopy of the three distant dwarf galaxies of M31 Lacerta I, Cassiopeia III, and Perseus I, recently discovered within the Pan-STARRS1 3π imaging survey. The systemic velocities of the three systems (v {sub r,} {sub helio} = –198.4 ± 1.1 km s{sup –1}, –371.6 ± 0.7 km s{sup –1}, and –326 ± 3 km s{sup –1}, respectively) confirm that they are satellites of M31. In the case of Lacerta I and Cassiopeia III, the high quality of the data obtained for 126 and 212 member stars, respectively, yields reliable constraints on their global velocity dispersions (σ{submore » vr} = 10.3 ± 0.9 km s{sup –1} and 8.4 ± 0.6 km s{sup –1}, respectively), leading to dynamical-mass estimates for both of ∼4 × 10{sup 7} M {sub ☉} within their half-light radius. These translate to V-band mass-to-light ratios of 15{sub −9}{sup +12} and 8{sub −5}{sup +9} in solar units. We also use our spectroscopic data to determine the average metallicity of the three dwarf galaxies ([Fe/H] = –2.0 ± 0.1, –1.7 ± 0.1, and –2.0 ± 0.2, respectively). All these properties are typical of dwarf galaxy satellites of Andromeda with their luminosity and size.« less

DISCOVERY OF RAPIDLY MOVING PARTIAL X-RAY ABSORBERS WITHIN GAMMA CASSIOPEIAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamaguchi, K.; Oskinova, L.; Russell, C. M. P.

2016-12-01

Gamma Cassiopeiae is an enigmatic Be star with unusually strong hard X-ray emission. The Suzaku observatory detected six rapid X-ray spectral hardening events called “softness dips” in a ∼100 ks observation in 2011. All the softness dip events show symmetric softness-ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either ∼40% or ∼70% partial covering absorption to kT  ∼ 12 keV plasma emission by matter with a neutral hydrogen column density of ∼(2−8) × 10{sup 21} cm{sup −2}, while the spectrum outside these dips is almost free of absorption. This resultmore » suggests the presence of two distinct X-ray-emitting spots in the γ  Cas system, perhaps on a white dwarf (WD) companion with dipole mass accretion. The partial covering absorbers may be blobs in the Be stellar wind, the Be disk, or rotating around the WD companion. Weak correlations of the softness ratios to the hard X-ray flux suggest the presence of stable plasmas at kT  ∼ 0.9 and 5 keV, which may originate from the Be or WD winds. The formation of a Be star and WD binary system requires mass transfer between two stars; γ  Cas may have experienced such activity in the past.« less

Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2010-08-13

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here in this paper, we report the Fermi Large Area Telescope detection of variable γ-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particlesmore » can be accelerated effectively to produce π 0 decay γ-rays from proton-proton interactions. Lastly, emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.« less

Rapid re-brightening of the red nova V4332 Sgr remnant

NASA Astrophysics Data System (ADS)

Goranskij, V. P.; Zharova, A. V.; Barsukova, E. A.; Valeev, A. F.

2018-06-01

V4332 Sgr is a luminous red nova exploded in 1994. We perform CCD BVRcIc photometry of its remnant since 2003, and medium resolution spectroscopy since 2005 using Russian 6 m telescope BTA, SAO 1 m Zeiss telescope and smaller telescopes of SAI Crimean Station.

XMM-Newton X-ray spectra of V407 Lup (Nova Lup 2016)

NASA Astrophysics Data System (ADS)

Ness, Jan-Uwe; Starrfield, Sumner; Woodward, Chick E.; Kuin, Paul; Page, Kim; Beardmore, Andy; Osborne, Julian; Sala, Gloria; Hernanz, Margarita; Orio, Marina; Williams, Bob

2017-09-01

Nova Lup 2016 (V407 Lup) was observed by XMM-Newton from 11 March 2017, 11:45 to 17:08 UT, 168 days after outburst (ATel #9538) with an exposure duration of 23,000 s. The EPIC pn was operated in Timing Mode with Medium filter.

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.

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

NASA Astrophysics Data System (ADS)

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

2016-01-01

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

V458 Vul (Nova Vul 2007) becomes a highly-variable supersoft X-ray source

NASA Astrophysics Data System (ADS)

Drake, J. J.; Page, K. L.; Osborne, J. P.; Beardmore, A. P.; Ness, J.-U.; Starrfield, S.; Schwarz, G.; Tsujimoto, M.; Wesson, R.; Bode, M.; Rodriguez-Gil, P.; Gaensicke, B.; Steeghs, D.; Knigge, C.; Takei, D.; Zijlstra, A.

2008-09-01

Swift X-ray Telescope (XRT) monitoring observations of V458 Vul (Nova Vul 2007, S. Nakano, IAUC 8861) have found it to be entering a new phase characterised by a highly variable supersoft X-ray component accompanied by partially anti-correlated variations in the ultraviolet. An earlier report of entry into the supersoft phase (ATel #1246) has proven premature. XRT observations obtained from 2008 June 18 - September 1 found the nova to have declined in X-ray luminosity by a factor of 3 to an average of 0.02 count/s in the 0.3-10 keV band compared with the 2007 November-December period (ATel #1603).

Follow-up spectroscopy and photometry of Dwarf Nova V392 Per

NASA Astrophysics Data System (ADS)

Mugrauer, M.; Gilbert, H.; Hoffmann, S.

2018-05-01

On 2018 May 1th 20 UT (JD=2458240.333) we took spectroscopic data of the dwarf nova V392 Per (ATel #11588; ATel #11601; ATel #11605) with the echelle spectrograph FLECHAS (Mugrauer et al. 2014, AN 335, 417) at the 90cm telescope of the University Observatory Jena.

Far Ultraviolet Spectroscopy of Seven Nova-Like Variables

NASA Astrophysics Data System (ADS)

Mizusawa, Trisha; Merritt, Jason; Ballouz, Ronald-Louis; Bonaro, Michael; Foran, Sean; Plumberg, Christopher; Stewart, Heather; Wiley, Trayer; Sion, Edward M.

2010-03-01

We present the results of a multicomponent synthetic spectral analysis of the archival far ultraviolet spectra of several key nova-like variables including members of the SW Sex, RW Tri, UX UMa, and VY Scl subclasses: KR Aur, RW Tri, V825 Her, V795 Her, BP Lyn, V425 Cas, and HL Aqr. Accretion rates as well as the possible flux contribution of the accreting white dwarf are included in our analysis. Except for RW Tri, which has a reliable trigonometric parallax, we computed the distances to the nova-like systems using the method of Knigge. Our analysis of seven archival IUE spectra of RW Tri at its parallax distance of 341 pc consistently indicates a low mass (˜0.4 M⊙) white dwarf and an average accretion rate, . For KR Aur, we estimate that the white dwarf has Teff = 29,000 ± 2000 K, log g = 8.4, and contributes 18% of the far-UV flux, while an accretion disk with accretion rate at an inclination of 41° contributes the remainder. We find that an accretion disk dominates the far-UV spectrum of V425 Cas but a white dwarf contributes nonnegligibly with approximately 18% of the far-UV flux. For the two high state nova-likes, HL Aqr and V825 Her, their accretion disks totally dominate with and 3 × 10-9 M⊙ yr-1, respectively. For BP Lyn we find while for V795 Her, we find an accretion rate of . We discuss the implications of our results for the evolutionary status of nova-like variables.

MID-INFRARED SPECTROSCOPIC OBSERVATIONS OF THE DUST-FORMING CLASSICAL NOVA V2676 OPH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawakita, Hideyo; Arai, Akira; Shinnaka, Yoshiharu

2017-02-01

The dust-forming nova V2676 Oph is unique in that it was the first nova to provide evidence of C{sub 2} and CN molecules during its near-maximum phase and evidence of CO molecules during its early decline phase. Observations of this nova have revealed the slow evolution of its lightcurves and have also shown low isotopic ratios of carbon ({sup 12}C/{sup 13}C) and nitrogen ({sup 14}N/{sup 15}N) in its envelope. These behaviors indicate that the white dwarf (WD) star hosting V2676 Oph is a CO-rich WD rather than an ONe-rich WD (typically larger in mass than the former). We performed mid-infraredmore » spectroscopic and photometric observations of V2676 Oph in 2013 and 2014 (respectively 452 and 782 days after its discovery). No significant [Ne ii] emission at 12.8 μ m was detected at either epoch. These provided evidence for a CO-rich WD star hosting V2676 Oph. Both carbon-rich and oxygen-rich grains were detected in addition to an unidentified infrared feature at 11.4 μ m originating from polycyclic aromatic hydrocarbon molecules or hydrogenated amorphous carbon grains in the envelope of V2676 Oph.« less

Search for Gamma-Ray Emission from Galactic Novae using Fermi-LAT Pass 8

NASA Astrophysics Data System (ADS)

Buson, Sara; Franckowiak, Anna; Cheung, Teddy; Jean, Pierre; Fermi-LAT Collaboration

2016-01-01

Recently Galactic novae have been identified as a new class of GeV gamma-ray emitters, with 6 detected so far with the Fermi Large Area Telescope (Fermi-LAT) data. Based on optical observations we have compiled a catalog of ~70 Galactic novae, which peak (in optical) during the operations of the Fermi mission. Based on the properties of known gamma-ray novae we developed a search procedure that we apply to all novae in the catalog to detect these slow transient sources or set flux upper limits using the Fermi-LAT Pass 8 data set. This is the first time a large sample of Galactic novae has been uniformly studied.

The Convolutional Visual Network for Identification and Reconstruction of NOvA Events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Psihas, Fernanda

In 2016 the NOvA experiment released results for the observation of oscillations in the vμ and ve channels as well as ve cross section measurements using neutrinos from Fermilab’s NuMI beam. These and other measurements in progress rely on the accurate identification and reconstruction of the neutrino flavor and energy recorded by our detectors. This presentation describes the first application of convolutional neural network technology for event identification and reconstruction in particle detectors like NOvA. The Convolutional Visual Network (CVN) Algorithm was developed for identification, categorization, and reconstruction of NOvA events. It increased the selection efficiency of the ve appearancemore » signal by 40% and studies show potential impact to the vμ disappearance analysis.« less

The Expanding Bipolar Shell of the Helium Nova V445 Puppis

NASA Astrophysics Data System (ADS)

Woudt, P. A.; Steeghs, D.; Karovska, M.; Warner, B.; Groot, P. J.; Nelemans, G.; Roelofs, G. H. A.; Marsh, T. R.; Nagayama, T.; Smits, D. P.; O'Brien, T.

2009-11-01

From multi-epoch adaptive optics imaging and integral field unit spectroscopy, we report the discovery of an expanding and narrowly confined bipolar shell surrounding the helium nova V445 Puppis (Nova Puppis 2000). An equatorial dust disc obscures the nova remnant, and the outflow is characterized by a large polar outflow velocity of 6720 ± 650 km s-1 and knots moving at even larger velocities of 8450 ± 570 km s-1. We derive an expansion parallax distance of 8.2 ± 0.5 kpc and deduce a pre-outburst luminosity of the underlying binary of log L/L sun = 4.34 ± 0.36. The derived luminosity suggests that V445 Puppis probably contains a massive white dwarf accreting at high rate from a helium star companion making it part of a population of binary stars that potentially lead to supernova Ia explosions due to accumulation of helium-rich material on the surface of a massive white dwarf.

Photometric and Spectroscopic Analysis of Classical Novae: An Examination of Their Observational Characteristics and Greater Astronomical Impact

NASA Astrophysics Data System (ADS)

Helton, Lorren Andrew

2010-12-01

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 from selected Galactic CNe observed as part of a 5 year, panchromatic optical/infrared observing campaign using Spitzer, Gemini, and other ground based optical facilities. In particular, I present detailed analysis of nova V1065 Centauri, including photoionization analysis of the emission lines, which enabled the derivation of abundances in the ejecta, and radiative transport modeling of the dust emission features, which allowed determination of the composition and characteristics of the dust in this system. I present analysis of three novae, V1974 Cygni, V382 Velorum, and V1494 Aquilae, observed from 4.4--15.5 years after outburst, discuss the characteristics of the nebulae at these late times, and estimate the abundances in their ejecta. In the case of V1494 Aql, I also report the first detection of neon. Finally, I present observations of three novae, DZ Crucis, V2361 Cygni, and V2362 Cygni, that exhibited unidentified infrared (UIR) features in their mid-infrared spectra, which exhibited unusual characteristics. I relate these features to other dusty novae in which features with similar characteristics were observed, and discuss possible sources for the UIR carriers. Analysis of the data obtained in the CNe monitoring campaign presented here highlights the need for synoptic observations obtained with broad wavelength coverage. Observations of V1065 Cen, which exhibited spectra rich in metals (e.g O, Ne, Mg, S, Ar, and Fe) produced during the thermonuclear runaway and through dredge up from the surface layers of the underlying WD, yielded robust estimates of WD composition, ejecta mass, and absolute abundances in the ejecta. Dusty novae such as V1065 Cen, V2362 Cyg, and V2361 Cyg, produced 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. This data set is exceptional in that observations of many targets commenced immediately after eruption and followed 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.

History of Chandra X-Ray Observatory

NASA Image and Video Library

1999-08-01

This x-ray image of the Cassiopeia A (CAS A) supernova remnant is the official first light image of the Chandra X-Ray Observatory (CXO). The 5,000-second image was made with the Advanced Charged Coupled Device (CCD) Image Spectrometer (ACIS). Two shock waves are visible: A fast outer shock and a slower irner shock. The inner shock wave is believed to be due to the collision of ejecta from the supernova explosion with a circumstellar shell of material, heating it to a temperature of 10 million-degrees Celsius. The outer shock wave is analogous to an awesome sonic boom resulting from this collision The x-rays reveal a bright object near the center, which may be the long-sought neutron star or black hole remnant of the explosion that produced Cassiopeia A. Cassiopeia A is the 320-year-old remnant of a massive star that exploded. Located in the constellation Cassiopeia, it is 10 light-years across and 10,000 light-years from Earth. A supernova occurs when a massive star has used up its nuclear fuel and the pressure drops in the central core of the star. The matter in the core is crushed by gravity to higher and higher densities, and temperatures reach billions of degrees. Under these extreme conditions, nuclear reactions occur violently and catastrophically, reversing the collapse. A thermonuclear shock wave races through the now expanding stellar debris, fusing lighter elements into heavier ones and producing a brilliant visual outburst.

A Million-Second Chandra View of Cassiopeia A

NASA Technical Reports Server (NTRS)

Hwang, Una; Laming, J. Martin; Badenes, Carles; Berendse, Fred; Blondin, John; Cioffi, Denis; DeLaney, Tracey; Dewey, Daniel; Fesen, Robert; Flanagan, Kathryn A.

2004-01-01

We introduce a million-second observation of the supernova remnant Cassiopeia A with the Chandra X-ray Observatory. The bipolar structure of the Si-rich ejecta (NE jet and SW counterpart) is clearly evident in the new images, and their chemical similarity is confirmed by their spectra. These are most likely due to jets of ejecta as opposed to cavities in the circumstellar medium, since we can reject simple models for the latter. The properties of these jets and the Fe-rich ejecta will provide clues to the explosion of Cas A.

Student Measurements of the Double Star Eta Cassiopeiae

NASA Astrophysics Data System (ADS)

Brewer, Mark; Cacace, Gabriel; Do, Vivian; Griffith, Nicholas; Malan, Alexandria; Paredes, Hanna; Peticolas, Brian; Stasiak, Kathryne

2016-10-01

The double star Eta Cassiopeiae was measured at Vanguard Preparatory School. Digital measurements were made with a 14-inch telescope equipped with a CCD camera. The plate scale was determined to be 0.50 arcseconds per pixel. The separations and position angles were determined to be 13.3 arcseconds and 340.4 degrees, by the use of astronomy software. Previous observations reported in the Washington Double Star Catalog were used as a comparison. The camera angle was found to be the ultimate issue in the skewed data gathered for the double star.

Heavy ion irradiation-induced microstructural evolution in pyrochlore Lu{sub 2}Ti{sub 2}O{sub 7} at room temperature and 723 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Q.R.; Zhang, J., E-mail: zhangjian@xmu.edu.cn; Dong, X.N.

Polycrystalline pyrochlore Lu{sub 2}Ti{sub 2}O{sub 7} pellets were irradiated with 600 keV Kr{sup 3+} at room temperature and 723 K to a fluence of 4×10{sup 15} ions/cm{sup 2}, corresponding to an average ballistic damage dose of 10 displacements per atom in the peak damage region. Irradiation-induced microstructural evolution was examined by grazing incidence X-ray diffraction, and cross-sectional transmission electron microscopy. Incomplete amorphization was observed in the sample irradiated at room temperature due to the formation of nano-crystal which has the identical structure of pyrochlore, and the formation of nano-crystal is attributed to the mechanism of epitaxial recrystallization. However, an orderedmore » pyrochlore phase to a swelling disordered fluorite phase transformation is occurred for the Lu{sub 2}Ti{sub 2}O{sub 7} sample irradiated at 723 K, which is due to the disordering of metal cations and anion vacancies. - Graphical Abstract: Polycrystalline pyrochlore Lu{sub 2}Ti{sub 2}O{sub 7} pellets were irradiated with 600 keV Kr{sup 3+} to a fluence of 4×10{sup 15} ions/cm{sup 2} at room temperature and 723 K, Incomplete amorphization was observed in the sample irradiated at room temperature due to the formation of nano-crystal. However, an ordered pyrochlore phase to a swelling disordered fluorite phase transformation is occurred for the Lu{sub 2}Ti{sub 2}O{sub 7} sample irradiated at 723 K, which is due to the disordering of metal cations and anion vacancies. - Highlights: Pyrochlore Lu{sub 2}Ti{sub 2}O{sub 7} pellets were irradiated by heavy ions at RT and 723 K. At RT irradiation, ~75% of amorphization was achieved. The nano-crystals were formed in the damage layer at RT irradiation. The formed nano-crystals enhanced the radiation tolerance of Lu{sub 2}Ti{sub 2}O{sub 7}. A pyrochlore to fluorite phase transformation was observed at 723 K irradiation.« less

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 V4743 Sgr showed the prominent He II 4686 A line and the Bowen blend, which indicate a hot region, with peak temperature in the ultraviolet range. This may be the same region that previously emitted supersoft X-rays, and later cooled shifting the peak of emission to the ultraviolet.

Nova Sco 2016 No. 2 = PNV J17225112-3158349 = ASASSN-16kd

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2016-09-01

AAVSO Alert Notice 550 announces the independent discovery of Nova Sco 2016 No. 2 = ASASSN-16kd = PNV J17225112-3158349 = V1656 Sco by Shigehisa Fujikawa (Kan'onji, Kagawa, Japan) at unfiltered CCD magnitude 11.6 on 2016 September 06.481 UT; and by ASAS-SN (Stanek et al., ATel #9469) at 12.13 V on 2016 September 06.00 UT. Spectroscopy indicating that Nova Sco 2016 No. 2 is a highly reddened classical Fe II-type nova was obtained by Arai and Honda (CBET 4320); by Bohlsen (ATel #9477); by Bersier et al. (ATel #9478); and by Prieto et al. (ATel #9479). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

The 21 Na (p,γ) 22 Mg reaction from Ec.m. =200 to 1103 keV in novae and x-ray bursts

NASA Astrophysics Data System (ADS)

D'Auria, J. M.; Azuma, R. E.; Bishop, S.; Buchmann, L.; Chatterjee, M. L.; Chen, A. A.; Engel, S.; Gigliotti, D.; Greife, U.; Hunter, D.; Hussein, A.; Hutcheon, D.; Jewett, C. C.; José, J.; King, J. D.; Laird, A. M.; Lamey, M.; Lewis, R.; Liu, W.; Olin, A.; Ottewell, D.; Parker, P.; Rogers, J.; Ruiz, C.; Trinczek, M.; Wrede, C.

2004-06-01

The long-lived radioactive nuclide 22 Na ( t1/2 =2.6 yr) is an astronomical observable for understanding the physical processes of oxygen-neon novae. Yields of 22Na in these events are sensitive to the unknown total rate of the 21 Na (p,γ) 22 Mg reaction. Using a high intensity 21 Na beam at the TRIUMF-ISAC facility, the strengths of seven resonances in 22 Mg , of potential astrophysical importance, have been directly measured at center of mass energies from Ec.m. =200 to 1103 keV . We report the results obtained for these resonances and their respective contributions to the 21 Na (p,γ) 22 Mg rate in novae and x-ray bursts, and their impact on 22 Na production in novae.

Kepler Observations of V447 Lyr: an Eclipsing U Gem Cataclysmic Variable

NASA Technical Reports Server (NTRS)

Ramsay, Gavin; Cannizzo, John K.; Howell, Steve B.; Wood, Matt A.; Still, Martin; Barclay, Thomas; Smale, Alan

2012-01-01

We present the results of an analysis of Kepler data covering 1.5 yr of the dwarf nova V447 Lyr. We detect eclipses of the accretion disc by the mass donating secondary star every 3.74 h which is the binary orbital period. V447 Lyr is therefore the first dwarf nova in the Kepler field to show eclipses.We also detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem-type dwarf nova. We show that the orbital phase of the mid-eclipse occurs earlier during outbursts compared to quiescence and that the width of the eclipse is greater during outburst. This suggests that the bright spot is more prominent during quiescence and that the disc is larger during outburst than quiescence. This is consistent with an expansion of the outer disc radius due to the presence of high viscosity material associated with the outburst, followed by a contraction in quiescence due to the accretion of low angular momentum material. We note that the long outbursts appear to be triggered by a short outburst, which is also observed in the super-outbursts of SU UMa dwarf novae as observed using Kepler.

On the Progenitor System of V392 Persei

NASA Astrophysics Data System (ADS)

Darnley, M. J.; Starrfield, S.

2018-05-01

A discussion regarding the progenitor system of the nova and dwarf nova system V392 Persei using archival data from 2MASS and WISE. We find that the system is unlikely to contain a luminous red giant donor (i.e. a symbiotic system), but cannot exclude the presence of a lower luminosity red giant or a sub-giant donor. The similarity of the SED of the quiescent V392 Per to that of GK Persei is noted.

Evidence for GeV cosmic rays from white dwarfs in the local cosmic ray spectra and in the gamma-ray emissivity of the inner Galaxy

NASA Astrophysics Data System (ADS)

Kamae, Tuneyoshi; Lee, Shiu-Hang; Makishima, Kazuo; Shibata, Shinpei; Shigeyama, Toshikazu

2018-03-01

Recent observations found that electrons are accelerated to ˜10 GeV and emit synchrotron hard X-rays in two magnetic white dwarfs (WDs), also known as cataclysmic variables (CVs). In nova outbursts of WDs, multi-GeV gamma-rays were detected, implying that protons are accelerated to 100 GeV or higher. In recent optical surveys, the WD density is found to be higher near the Sun than in the Galactic disk by a factor ˜2.5. The cosmic rays (CRs) produced by local CVs and novae will accumulate in the local bubble for 106-107 yr. On these findings, we search for CRs from historic CVs and novae in the observed CR spectra. We model the CR spectra at the heliopause as sums of Galactic and local components based on observational data as much as possible. The initial Galactic CR electron and proton spectra are deduced from the gamma-ray emissivity, the local electron spectrum from the hard X-ray spectra at the CVs, and the local proton spectrum from gamma-ray spectra at novae. These spectral shapes are then expressed in a simple set of polynomial functions of CR energy and regressively fitted until the high-energy (>100 GeV) CR spectra near Earth and the Voyager-1 spectra at the heliopause are reproduced. We then extend the modeling to nuclear CR spectra and find that one spectral shape fits all local nuclear CRs, and that the apparent hardening of the nuclear CR spectra is caused by the roll-down of local nuclear spectra around 100-200 GeV. All local CR spectra populate a limited energy band below 100-200 GeV and enhance gamma-ray emissivity below ˜10 GeV. Such an enhancement is observed in the inner Galaxy, suggesting the CR fluxes from CVs and novae are substantially higher there.

Constraints on oscillation parameters from v e appearance and v μ disappearance in NOvA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamson, P.; Aliaga, L.; Ambrose, D.

2017-06-05

Results are reported from an improved measurement of ν μ → ν e transitions by the NOvA experiment. Using an exposure equivalent to 6.05 × 10 20 protons on target, 33 νe candidates are observed with a background of 8.2 ± 0.8 (syst.). In this paper, combined with the latest NOvA νμ disappearance data and external constraints from reactor experiments on sin 22θ 13, the hypothesis of inverted mass hierarchy with θ 23 in the lower octant is disfavored at greater than 93% C.L. for all values of δ CP.

Far Ultraviolet Spectroscopy of Three Long Period Nova-Like Variables, V363 Aur, AC Cnc and RZ Gru

NASA Astrophysics Data System (ADS)

Bisol, Alexandra; Sion, E. M.

2011-01-01

We have selected three nova-like variables: V363 Aur, RZ Gru and AC Cnc, all of which are UX UMa types, having similar orbital periods well beyond the 3 to 4 hour range where most nova-likes are found. All should have very similar secondary stars given the fact that they their physical parameters are so similar. V363 Aur is a bona fide SW Sex star, and AC Cnc is a probable one, while RZ Gru is not a member of the SW Sex subclass. Our objective is to carry out the first synthetic spectral analysis of far ultraviolet spectra of the three systems using state-of-the-art models both of accretion disks and photospheres. Therefore we shall compare the distances we obtain from the best fitting synthetic spectral models to other distance estimates in the literature. We present model-derived accretion rates and distances for all three systems. The FUV flux range of RZ Gru and V363 Aur is dominated by radiation from an optically thick, steady state, accretion but for AC Cnc, we find that a hot white dwarf accounts for 70% of the FUV flux. We compare the FUV characteristics and physical properties of these three long period nova-like systems to the properties of other nova-likes at shorter periods. This work was supported in part by NSF grant AST0807892 to Villanova University.

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.

Synoptic GNIRS XD Spectra ToO Novae

NASA Astrophysics Data System (ADS)

Woodward, Chick; Helton, Andrew; Spitzer/Chandra Team

2007-02-01

Novae are important contributors to galactic chemical enrichment on local scales. NIR spectroscopy of novae provides information about the elemental abundances of the gas and dust in the ejecta dispersing into the ISM as well as kinematic information related to the outburst. We propose to obtain synoptic GNIRS spectra of select Target of Opportunity (ToO) novae in the Magellanic Clouds (MC) and the galaxy to study the dynamics of the ejecta, to determine the temporal evolution of coronal lines and recombination lines (measuring their strength and velocity profiles), and to determine abundances. Being all equidistant, MC nova permit a more robust analysis of distant-dependent physical parameters of outburst than is generally possible for Galactic novae. The GNIRS data will provide critical spectral coverage and synoptic data to complement extant Spitzer and Chandra nova programs. Triggering of the GNIRS program will occur when a nova becomes brighter than V=12 mag, (assuming that adequate PWFS guide stars exist) as reported in the IAUC or CBET.

Multiwavelength observations of nova SMCN 2016-10a - one of the brightest novae ever observed

NASA Astrophysics Data System (ADS)

Aydi, E.; Page, K. L.; Kuin, N. P. M.; Darnley, M. J.; Walter, F. M.; Mróz, P.; Buckley, D. A. H.; Mohamed, S.; Whitelock, P.; Woudt, P.; Williams, S. C.; Orio, M.; Williams, R. E.; Beardmore, A. P.; Osborne, J. P.; Kniazev, A.; Ribeiro, V. A. R. M.; Udalski, A.; Strader, J.; Chomiuk, L.

2018-02-01

We report on multiwavelength observations of nova Small Magellanic Cloud Nova 2016-10a. The present observational set is one of the most comprehensive for any nova in the Small Magellanic Cloud, including low-, medium-, and high-resolution optical spectroscopy and spectropolarimetry from Southern African Large Telescope, Folded Low-Order Yte-Pupil Double-Dispersed Spectrograph, and Southern Astrophysical Research; long-term Optical Gravitational Lensing Experiment V- and I-bands photometry dating back to 6 yr before eruption; Small and Moderate Aperture Research Telescope System optical and near-IR photometry from ˜11 d until over 280 d post-eruption; Swift satellite X-ray and ultraviolet observations from ˜6 d until 319 d post-eruption. The progenitor system contains a bright disc and a main sequence or a sub-giant secondary. The nova is very fast with t2 ≃ 4.0 ± 1.0 d and t3 ≃ 7.8 ± 2.0 d in the V band. If the nova is in the SMC, at a distance of ˜61 ± 10 kpc, we derive MV, max ≃ -10.5 ± 0.5, making it the brightest nova ever discovered in the SMC and one of the brightest on record. At day 5 post-eruption the spectral lines show a He/N spectroscopic class and an Full Width at Half Maximum of ˜3500 km s-1, indicating moderately high ejection velocities. The nova entered the nebular phase ˜20 d post-eruption, predicting the imminent super-soft source turn-on in the X-rays, which started ˜28 d post-eruption. The super-soft source properties indicate a white dwarf mass between 1.2 and 1.3 M⊙ in good agreement with the optical conclusions.

V5588 SGR = Nova Sagittarii 2011 No. 2 = Pnv J18102135-2305306

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2011-04-01

Announces the discovery of Nova Sgr 2011 No. 2 = V5588 SGR = PNV J18102135-2305306 by Koichi Nishiyama (Kurume, Japan) and Fujio Kabashima (Miyaki, Japan) on ~ 2011 March 27.832 UT at unfiltered CCD magnitude mag 11.7. Spectra obtained by A. Arai, M. Nagashima, T. Kajikawa, and C. Naka (Koyama Astronomical Observatory, Kyoto Sangyo University) on Mar. 28.725 UT suggest that the object is a classical nova reddened by interstellar matter. The object was designated PNV J18102135-2305306 when posted on the Central Bureau's Transient Objects Confirmation Page (TOCP) webpage. E. Kazarovets, on behalf of the GCVS team, reports that the name V5588 Sgr has been assigned to this nova. It was nitially announced in CBET 2679 (Daniel W. E. Green, ed.) and AAVSO Special Notice #237 (Waagen). Additional information published in IAU Circular 9203 (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.

V2676 Oph: Estimating Physical Parameters of a Moderately Fast Nova

NASA Astrophysics Data System (ADS)

Raj, A.; Pavana, M.; Kamath, U. S.; Anupama, G. C.; Walter, F. M.

2018-03-01

Using our previously reported observations, we derive some physical parameters of the moderately fast nova V2676 Oph 2012 #1. The best-fit Cloudy model of the nebular spectrum obtained on 2015 May 8 shows a hot white dwarf source with TBB≍1.0×105 K having a luminosity of 1.0×1038 erg/s. Our abundance analysis shows that the ejecta are significantly enhanced relative to solar, He/H=2.14, O/H=2.37, S/H=6.62 and Ar/H=3.25. The ejecta mass is estimated to be 1.42×10-5 M⊙. The nova showed a pronounced dust formation phase after 90 d from discovery. The J-H and H-K colors were very large as compared to other molecule- and dust-forming novae in recent years. The dust temperature and mass at two epochs have been estimated from spectral energy distribution fits to infrared photometry.

First measurement of the 34S(p ,γ )35Cl reaction rate through indirect methods for presolar nova grains

NASA Astrophysics Data System (ADS)

Gillespie, S. A.; Parikh, A.; Barton, C. J.; Faestermann, T.; José, J.; Hertenberger, R.; Wirth, H.-F.; de Séréville, N.; Riley, J. E.; Williams, M.

2017-08-01

Sulphur isotopic ratio measurements may help to establish the astrophysical sites in which certain presolar grains were formed. Nova model predictions of the 34S/32S ratio are, however, unreliable due to the lack of an experimental 34S(p ,γ )35Cl reaction rate. To this end, we have measured the 34S(3He,d )35Cl reaction at 20 MeV using a high resolution quadrupole-dipole-dipole-dipole magnetic spectrograph. Twenty-two levels over 6.2 MeV

Variability of young stars: Determination of rotational periods of weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region

NASA Astrophysics Data System (ADS)

Koeltzsch, A.; Mugrauer, M.; Raetz, St.; Schmidt, T. O. B.; Roell, T.; Eisenbeiss, T.; Hohle, M. M.; Vaňko, M.; Ginski, Ch.; Marka, C.; Moualla, M.; Schreyer, K.; Broeg, Ch.; Neuhäuser, R.

2009-05-01

We report on observation and determination of rotational periods of ten weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region. Observations were carried out with the Cassegrain-Teleskop-Kamera (CTK) at University Observatory Jena between 2007 June and 2008 May. The periods obtained range between 0.49 d and 5.7 d, typical for weak-line and post T Tauri stars. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

Order Amidst Chaos of Star's Explosion

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Click on the image for movie of Order Amidst Chaos of Star's Explosion

This artist's animation shows the explosion of a massive star, the remains of which are named Cassiopeia A. NASA's Spitzer Space Telescope found evidence that the star exploded with some degree of order, preserving chunks of its onion-like layers as it blasted apart.

Cassiopeia A is what is known as a supernova remnant. The original star, about 15 to 20 times more massive than our sun, died in a cataclysmic 'supernova' explosion viewable from Earth about 340 years ago. The remnant is located 10,000 light-years away in the constellation Cassiopeia.

The movie begins by showing the star before it died, when its layers of elements (shown in different colors) were stacked neatly, with the heaviest at the core and the lightest at the top. The star is then shown blasting to smithereens. Spitzer found evidence that the star's original layers were preserved, flinging outward in all directions, but not at the same speeds. In other words, some chunks of the star sped outward faster than others, as illustrated by the animation.

The movie ends with an actual picture of Cassiopeia A taken by Spitzer. The colored layers containing different elements are seen next to each other because they traveled at different speeds.

The infrared observatory was able to see the tossed-out layers because they light up upon ramming into a 'reverse' shock wave created in the aftermath of the explosion. When a massive star explodes, it creates two types of shock waves. The forward shock wave darts out quickest, and, in the case of Cassiopeia A, is now traveling at supersonic speeds up to 7,500 kilometers per second (4,600 miles/second). The reverse shock wave is produced when the forward shock wave slams into a shell of surrounding material expelled before the star died. It tags along behind the forward shock wave at slightly slower speeds.

Chunks of the star that were thrown out fastest hit the shock wave sooner and have had more time to heat up to scorching temperatures previously detected by X-ray and visible-light telescopes. Chunks of the star that lagged behind hit the shock wave later, so they are cooler and radiate infrared light that was not seen until Spitzer came along. These lagging chunks are seen in false colors in the Spitzer picture of Cassiopeia A. They are made up of gas and dust containing neon, oxygen and aluminum -- elements from the middle layers of the original star.

The Long-Term Spectroscopic Misadventures of AG Dra with a Nod toward V407 Cyg: Degenerates Behaving Badly

NASA Technical Reports Server (NTRS)

Shore, S.N.; Genovali, K.; Wahlgren, G. M.

2013-01-01

We present some results of an ongoing study of the long-term spectroscopic variations of AG Dra, a prototypical eruptive symbiotic system. We discuss the effects of the environment and orbital modulation in this system and some of the physical processes revealed by a comparison with the nova outburst of the symbiotic-like recurrent nova V407 Cyg 2010.

Measurement of radiative proton capture on 18F and implications for oxygen-neon novae reexamined

NASA Astrophysics Data System (ADS)

Akers, C.; Laird, A. M.; Fulton, B. R.; Ruiz, C.; Bardayan, D. W.; Buchmann, L.; Christian, G.; Davids, B.; Erikson, L.; Fallis, J.; Hager, U.; Hutcheon, D.; Martin, L.; Murphy, A. St. J.; Nelson, K.; Ottewell, D.; Rojas, A.; Spyrou, A.

2016-12-01

Background: The rate of the 18F(p ,γ )19Ne reaction affects the final abundance of the radioisotope 18F ejected from novae. This nucleus is important as its abundance is thought to significantly influence the first-stage 511-keV and continuum γ -ray emission in the aftermath of novae. No successful measurement of this reaction existed prior to this work, and the rate used in stellar models had been calculated based on incomplete information from contributing resonances. Purpose: Of the two resonances thought to provide a significant contribution to the astrophysical reaction rate, located at Ec .m .=330 and 665 keV, the former has a radiative width estimated from the assumed analog state in the mirror nucleus, 19F, while the latter resonance does not have an analog state assignment, resulting in an arbitrary radiative width being assumed. As such, a direct measurement was needed to establish what role this resonance plays in the destruction of 18F at nova temperatures. This paper extends and takes the place of a previous Letter which reported the strength of the Ec .m .=665 keV resonance. Method: The DRAGON recoil separator was used to directly measure the strength of the important 665-keV resonance in this reaction, in inverse kinematics, by observing 19Ne reaction products. A radioactive 18F beam was provided by the ISAC facility at TRIUMF. R -matrix calculations were subsequently used to evaluate the significance of the results at astrophysical energies. Results: We report the direct measurement of the 18F(p ,γ )19Ne reaction with the reevaluation of several detector efficiencies and the use of an updated 19Ne level scheme in the reaction rate analysis. The strength of the 665-keV resonance (Ex=7.076 MeV) is found to be an order of magnitude weaker than currently assumed in nova models. An improved analysis of the previously reported data is presented here, resulting in a slightly different value for the resonance strength. These small changes, however, do not alter the primary conclusions. Conclusions: Reaction rate calculations definitively show that the 665-keV resonance plays no significant role in the destruction of 18F at nova temperatures.

Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

NASA Technical Reports Server (NTRS)

Hays, Elizabeth

2010-01-01

a) Symbiotic Binary System: White dwarf + red giant system. b) Nova: White dwarf builds up mass envelope to the point of thermonuclear fusion. c) Dramatic increase in visual magnitude. d) Recurrent Nova? e) Hints but no strong confirmation of previous nova f) Pre-nova activity: 1) White dwarf shows ongoing variability at level of several in magnitude. 2) V407 Cyg companion is a Mira star showing variability at level of several in magnitude. g) Origin of the gamma rays? 1) Strong shock propagating into dense medium around giant star land stellar wind. 2) Pion decay or electron processes?

Novae as Tevatrons: prospects for CTA and IceCube

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

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.

Mapping low-frequency carbon radio recombination lines towards Cassiopeia A at 340, 148, 54, and 43 MHz

NASA Astrophysics Data System (ADS)

Salas, P.; Oonk, J. B. R.; van Weeren, R. J.; Wolfire, M. G.; Emig, K. L.; Toribio, M. C.; Röttgering, H. J. A.; Tielens, A. G. G. M.

2018-04-01

Quantitative understanding of the interstellar medium requires knowledge of its physical conditions. Low-frequency carbon radio recombination lines (CRRLs) trace cold interstellar gas and can be used to determine its physical conditions (e.g. electron temperature and density). In this work, we present spatially resolved observations of the low-frequency (≤390 MHz) CRRLs centred around C268α, C357α, C494α, and C539α towards Cassiopeia A on scales of ≤1.2 pc. We compare the spatial distribution of CRRLs with other interstellar medium tracers. This comparison reveals a spatial offset between the peak of the CRRLs and other tracers, which is very characteristic for photodissociation regions and that we take as evidence for CRRLs being preferentially detected from the surfaces of molecular clouds. Using the CRRLs, we constrain the gas electron temperature and density. These constraints on the gas conditions suggest variations of less than a factor of 2 in pressure over ˜1 pc scales, and an average hydrogen density of 200-470 cm-3. From the electron temperature and density maps, we also constrain the ionized carbon emission measure, column density, and path length. Based on these, the hydrogen column density is larger than 1022 cm-2, with a peak of ˜4 × 1022 cm-2 towards the south of Cassiopeia A. Towards the southern peak, the line-of-sight length is ˜40 pc over a ˜2 pc wide structure, which implies that the gas is a thin surface layer on a large (molecular) cloud that is only partially intersected by Cassiopeia A. These observations highlight the utility of CRRLs as tracers of low-density extended H I and CO-dark gas halo's around molecular clouds.

INTEGRAL Observations of the Enigmatic Be Stars (gamma) Cassiopeiae and HD 110432

NASA Technical Reports Server (NTRS)

Sturner, S. J.; Shrader, C. R.

2007-01-01

We present the results of a hard X-ray study of the Be stars gamma Cassiopeiae and HD 110432 based on observations made with the INTEGRAL observatory. These stars are known to be moderately strong, X-ray sources (L(sub x) approx. equal to = 10(sup 32)-10(sup 33) erg per second). These values are at the extreme high end of the known luminosity distribution for active coronal systems, but several orders of magnitude below typical X-ray binaries. The hard X-ray spectra for these systems are quite similar. They can be well fitted by either optically thin thermal plasma models with kT = 12.5 - 14 keV or a cutoff powerlaw + gaussian line model with photon indices in the 1.3 - 1.5 range and a line energy of 6.7 keV. The 20-50 keV light curves show no evidence for flaring and no significant evidence for periodic variability. It has been proposed that the X-ray emission is due to either accretion onto a white dwarf companion or magnetic activity near the surface of the Be star. We discuss in detail the pros and cons of each scenario towards explaining our spectral and temporal results. Given that both thermal and nonthermal models fit the data equally well, we cannot use the spectra to delineate between these two scenarios. Recent observations indicate that gamma Cas has a approx. 1 solar mass companion in a 203.59 day orbit. This is consistent with the white dwarf - Be star binary model but the lack of periodic modulation of the flux on this timescale calls this conclusion into question. On the other hand the lack of flaring activity may rule against the magnetic activity model. We discuss advances in observations and theory that need to be made to resolve the origin of these systems.

Suzaku Observation of the Classical Nova V2491 Cyg in Quiescence

NASA Technical Reports Server (NTRS)

Zemko, P.; Mukai, K.; Orio, M.

2015-01-01

We present Suzaku XIS observation of V2491 Cyg (Nova Cyg 2008 No. 2) obtained in quiescence, more than two years after the outburst. The nova was detected as a very luminous source in a wide spectral range from soft to hard X-rays. A very soft blackbody-like component peaking at 0.5 keV indicates that either we observe remaining, localized hydrogen burning on the surface of the white dwarf, or accretion onto a magnetized polar cap. In the second case, V2491 Cyg is a candidate "soft intermediate polar". We obtained the best fit for the X-ray spectra with several components: two of thermal plasma, a blackbody and a complex absorber. The later is typical of intermediate polars. The X-ray light-curve shows a modulation with an approximately 38 min period. The amplitude of this modulation is strongly energy dependent and reaches maximum in the 0.8-2.0 keV range. We discuss the origin of the X-ray emission and pulsations, and the likelihood of the intermediate polar scenario.

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

NASA Technical Reports Server (NTRS)

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

2014-01-01

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

The Korean 1592-1593 Record of a Guest Star: An 'Impostor' of the Cassiopeia A Supernova?

NASA Astrophysics Data System (ADS)

Park, Changbom; Yoon, Sung-Chul; Koo, Bon-Chul

2016-12-01

The missing historical record of the Cassiopeia A (Cas A) supernova (SN) event implies a large extinction to the SN, possibly greater than the interstellar extinction to the current SN remnant. Here we investigate the possibility that the guest star that appeared near Cas A in 1592-1593 in Korean history books could have been an `impostor' of the Cas A SN, i.e., a luminous transient that appeared to be a SN but did not destroy the progenitor star, with strong mass loss to have provided extra circumstellar extinction. We first review the Korean records and show that a spatial coincidence between the guest star and Cas A cannot be ruled out, as opposed to previous studies. Based on modern astrophysical findings on core-collapse SN, we argue that Cas A could have had an impostor and derive its anticipated properties. It turned out that the Cas A SN impostor must have been bright (M_V =-14.7 ± 2.2 mag) and an amount of dust with visual extinction of ≥ 2.8± 2.2 mag should have formed in the ejected envelope and/or in a strong wind afterwards. The mass loss needs to have been spherically asymmetric in order to see the light echo from the SN event but not the one from the impostor event.

Near-infrared and optical studies of the highly obscured nova V1831 Aquilae (Nova Aquilae 2015)

NASA Astrophysics Data System (ADS)

Banerjee, D. P. K.; Srivastava, Mudit K.; Ashok, N. M.; Munari, U.; Hambsch, F.-J.; Righetti, G. L.; Maitan, A.

2018-01-01

Near-infrared (NIR) and optical photometry and spectroscopy are presented for the nova V1831 Aquilae, covering the early decline and dust-forming phases during the first ∼90 d after its discovery. The nova is highly reddened due to interstellar extinction. Based solely on the nature of the NIR spectrum, we are able to classify the nova to be of the Fe II class. The distance and extinction to the nova are estimated to be 6.1 ± 0.5 kpc and Av ∼ 9.02, respectively. Lower limits of the electron density, emission measure and ionized ejecta mass are made from a Case B analysis of the NIR Brackett lines, while the neutral gas mass is estimated from the optical [O I] lines. We discuss the cause of the rapid strengthening of the He I 1.0830-μm line during the early stages. V1831 Aql formed a modest amount of dust fairly early (∼19.2 d after discovery); the dust shell is not seen to be optically thick. Estimates of the dust temperature, dust mass and grain size are made. Dust formation commences around day 19.2 at a condensation temperature of 1461 ± 15 K, suggestive of a carbon composition, following which the temperature is seen to decrease gradually to 950 K. The dust mass shows a rapid initial increase, which we interpret as being due to an increase in the number of grains, followed by a period of constancy, suggesting the absence of grain destruction processes during this latter time. A discussion of the evolution of these parameters is made, including certain peculiarities seen in the grain radius evolution.

Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

NASA Technical Reports Server (NTRS)

Hays, Elizabeth

2010-01-01

Topics include: Fermi LAT Collaboration groups; galactic results from LAT; a GeV, wide-field instrument; the 1FGL catalog, the Fermi LAT 1FGL source catalog, unidentified gamma-ray sources; variability in 1FGL sources; curvature in 1FGL sources; spectral-variability classification; pulsars and their wind nebulae; gamma-ray pulsars and MSPs; GeV PWN search; Crab pulsar and nebula; Vela X nebular of Vela pulsar; MSH 15-52; supernova remnants, resolved GeV sources, galactic transients, LAT unassociated transient detections; gamma rays from a nova; V407 Cyngi - a symbiotic nova; V407 Cygni: a variable star; and March 11 - a nova. Summary slides include pulsars everywhere, blazars, LAT as an electron detector, cosmic ray spectrum, the Large Area Telescope, the Fermi Observatory, LAT sensitivity with time, candidate gamma-ray events, on-orbit energy calibration and rate, a 1 year sky map, LAT automated science processing, reported GeV flares, early activity and spectacular flare, gamma-ray transients near the galactic plane , two early unassociated transients, counter part search - Fermi J0910-5404; counterpart search 3EG J0903-3531, and a new LAT transient - J1057-6027.

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.;

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

DOE PAGES

Cheung, C. C.

2014-07-31

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 2-3 week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linkedmore » to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources.« less

Classical-Nova Contribution to the Milky Way’s Al 26 Abundance: Exit Channel of the Key Al 25 ( p , γ ) Si 26 Resonance

DOE PAGES

Bennett, M. B.; Wrede, C.; Chipps, K. A.; ...

2013-12-04

We present that classical novae are expected to contribute to the 1809-keV Galactic γ-ray emission by producing its precursor 26Al, but the yield depends on the thermonuclear rate of the unmeasured 25Al(p,γ) 26Si reaction. Using the β decay of 26P to populate the key J π=3 + resonance in this reaction, we report the first evidence for the observation of its exit channel via a 1741.6±0.6(stat)±0.3(syst) keV primary γ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured γ-ray energy and intensity with other experimental data on 26Si, we find the center-of-mass energy and strength of the resonance to be E r=414.9±0.6(stat)±0.3(syst)±0.6(lit.) keV and ωγ=23±6(stat)more » $$+11\\atop{-10}$$(lit.) meV, respectively, where the last uncertainties are from adopted literature data. Finally, we use hydrodynamic nova simulations to model 26Al production showing that these measurements effectively eliminate the dominant experimental nuclear-physics uncertainty and we estimate that novae may contribute up to 30% of the Galactic 26Al.« less

Search for gamma-ray emission from Galactic novae with the Fermi -LAT

NASA Astrophysics Data System (ADS)

Franckowiak, A.; Jean, P.; Wood, M.; Cheung, C. C.; Buson, S.

2018-02-01

Context. A number of novae have been found to emit high-energy gamma rays (>100 MeV). However, the origin of this emission is not yet understood. We report on the search for gamma-ray emission from 75 optically detected Galactic novae in the first 7.4 years of operation of the Fermi Large Area Telescope using the Pass 8 data set. Aims: We compile an optical nova catalog including light curves from various resources and estimate the optical peak time and optical peak magnitude in order to search for gamma-ray emission to determine whether all novae are gamma-ray emitters. Methods: We repeated the analysis of the six novae previously identified as gamma-ray sources and developed a unified analysis strategy that we then applied to all novae in our catalog. We searched for emission in a 15 day time window in two-day steps ranging from 20 days before to 20 days after the optical peak time. We performed a population study with Monte Carlo simulations to set constraints on the properties of the gamma-ray emission of novae. Results: Two new novae candidates have been found at 2σ global significance. Although these two novae candidates were not detected at a significant level individually, taking them together with the other non-detected novae, we found a sub-threshold nova population with a cumulative 3σ significance. We report the measured gamma-ray flux for detected sources and flux upper limits for novae without significant detection. Our results can be reproduced by several gamma-ray emissivity models (e.g., a power-law distribution with a slope of 2), while a constant emissivity model (i.e., assuming novae are standard candles) can be rejected.

Search for gamma-ray emission from Galactic novae with the Fermi-LAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franckowiak, A.; Jean, P.; Wood, M.

Context. A number of novae have been found to emit high-energy gamma rays (>100 MeV). However, the origin of this emission is not yet understood. We report on the search for gamma-ray emission from 75 optically detected Galactic novae in the first 7.4 years of operation of the Fermi Large Area Telescope using the Pass 8 data set. Aims. We compile an optical nova catalog including light curves from various resources and estimate the optical peak time and optical peak magnitude in order to search for gamma-ray emission to determine whether all novae are gamma-ray emitters. Methods. We repeated themore » analysis of the six novae previously identified as gamma-ray sources and developed a unified analysis strategy that we then applied to all novae in our catalog. We searched for emission in a 15 day time window in two-day steps ranging from 20 days before to 20 days after the optical peak time. We performed a population study with Monte Carlo simulations to set constraints on the properties of the gamma-ray emission of novae. Results. Two new novae candidates have been found at ~ 2σ global significance. Although these two novae candidates were not detected at a significant level individually, taking them together with the other non-detected novae, we found a sub-threshold nova population with a cumulative 3σ significance. We report the measured gamma-ray flux for detected sources and flux upper limits for novae without significant detection. Lastly, our results can be reproduced by several gamma-ray emissivity models (e.g., a power-law distribution with a slope of 2), while a constant emissivity model (i.e., assuming novae are standard candles) can be rejected.« less

Search for gamma-ray emission from Galactic novae with the Fermi-LAT

DOE PAGES

Franckowiak, A.; Jean, P.; Wood, M.; ...

2018-02-05

Context. A number of novae have been found to emit high-energy gamma rays (>100 MeV). However, the origin of this emission is not yet understood. We report on the search for gamma-ray emission from 75 optically detected Galactic novae in the first 7.4 years of operation of the Fermi Large Area Telescope using the Pass 8 data set. Aims. We compile an optical nova catalog including light curves from various resources and estimate the optical peak time and optical peak magnitude in order to search for gamma-ray emission to determine whether all novae are gamma-ray emitters. Methods. We repeated themore » analysis of the six novae previously identified as gamma-ray sources and developed a unified analysis strategy that we then applied to all novae in our catalog. We searched for emission in a 15 day time window in two-day steps ranging from 20 days before to 20 days after the optical peak time. We performed a population study with Monte Carlo simulations to set constraints on the properties of the gamma-ray emission of novae. Results. Two new novae candidates have been found at ~ 2σ global significance. Although these two novae candidates were not detected at a significant level individually, taking them together with the other non-detected novae, we found a sub-threshold nova population with a cumulative 3σ significance. We report the measured gamma-ray flux for detected sources and flux upper limits for novae without significant detection. Lastly, our results can be reproduced by several gamma-ray emissivity models (e.g., a power-law distribution with a slope of 2), while a constant emissivity model (i.e., assuming novae are standard candles) can be rejected.« less

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.

DAQ Software Contributions, Absolute Scale Energy Calibration and Background Evaluation for the NOvA Experiment at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flumerfelt, Eric Lewis

2015-08-01

The NOvA (NuMI Off-axis v e [nu_e] Appearance) Experiment is a long-baseline accelerator neutrino experiment currently in its second year of operations. NOvA uses the Neutrinos from the Main Injector (NuMI) beam at Fermilab, and there are two main off-axis detectors: a Near Detector at Fermilab and a Far Detector 810 km away at Ash River, MN. The work reported herein is in support of the NOvA Experiment, through contributions to the development of data acquisition software, providing an accurate, absolute-scale energy calibration for electromagnetic showers in NOvA detector elements, crucial to the primary electron neutrino search, and through anmore » initial evaluation of the cosmic background rate in the NOvA Far Detector, which is situated on the surface without significant overburden. Additional support work for the NOvA Experiment is also detailed, including DAQ Server Administration duties and a study of NOvA’s sensitivity to neutrino oscillations into a “sterile” state.« less

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

The awakening of a classical nova from hibernation.

PubMed

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

2016-09-29

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 dwarf nova behaviour, implying that the mass-transfer rate increased considerably as a result of the nova explosion.

Photometry and spectroscopy of a newly discovered polar - Nova Cygni 1975 (V1500 CYG)

NASA Technical Reports Server (NTRS)

Kaluzny, Janusz; Chlebowski, Tomasz

1988-01-01

The paper reports photometric and spectroscopic observations which led to the conclusion that Nova Cygni 1975 (V1500 Cyg) is a polar (of AM Her-type).The CCD photometry confirms the constancy of the photometric period which is again interpreted as an orbital cycle. The time-resolved MMT spectra make it possible to reconstruct, under several assumptions, the basic system parameters: M1=0.9M solar mass and M2=0.31M solar mass.

Detection of a 9.4 min periodicity in the XMM-Newton and Chandra X-ray light curves of V407 Lup (Nova Lup 2016)

NASA Astrophysics Data System (ADS)

Beardmore, Andy; Dobrotka, Andrej; Ness, Jan-Uwe; Orio, Marina; Osborne, Julian; Page, Kim

2017-09-01

We report on the timing analysis of two long, uninterrupted X-ray observations of V407 Lup (also know as ASASSN-16kt and Nova Lup 2016; see ATel #9538, #9539, #9550, #9554, #9587, #9594 and #9644, #10632, #10722) performed with XMM-Newton for 22,000 s on 2017 March 11 and with the Chandra HRC_s and Low Energy Transmission Grating on 2017 August 30 for 34,000 s.

BK Lyncis: the oldest old nova and a Bellwether for cataclysmic variable evolution

NASA Astrophysics Data System (ADS)

Patterson, Joseph; Uthas, Helena; Kemp, Jonathan; de Miguel, Enrique; Krajci, Thomas; Foote, Jerry; Hambsch, Franz-Josef; Campbell, Tut; Roberts, George; Cejudo, David; Dvorak, Shawn; Vanmunster, Tonny; Koff, Robert; Skillman, David; Harvey, David; Martin, Brian; Rock, John; Boyd, David; Oksanen, Arto; Morelle, Etienne; Ulowetz, Joseph; Kroes, Anthony; Sabo, Richard; Jensen, Lasse

2013-09-01

We summarize the results of a 20-yr campaign to study the light curves of BK Lyn, a nova-like star strangely located below the 2 to 3 h orbital-period gap in the family of cataclysmic variables (CVs). Two apparent superhumps dominate the nightly light curves, with periods 4.6 per cent longer, and 3.0 per cent shorter, than the orbital period. The first appears to be associated with the star's brighter states (V ˜ 14), while the second appears to be present throughout and becomes very dominant in the low state (V ˜ 15.7). It is plausible that these arise, respectively, from a prograde apsidal precession and a retrograde nodal precession of the star's accretion disc. Starting in the year 2005, the star's light curve became indistinguishable from that of a dwarf nova - in particular, that of the ER UMa subclass. No such clear transition has ever been observed in a CV before. Reviewing all the star's oddities, we speculate: (a) BK Lyn is the remnant of the probable nova on 101 December 30, and (b) it has been fading ever since, but it has taken ˜2000 yr for the accretion rate to drop sufficiently to permit dwarf-nova eruptions. If such behaviour is common, it can explain other puzzles of CV evolution. One: why the ER UMa class even exists (because all members can be remnants of recent novae). Two: why ER UMa stars and short-period nova-likes are rare (because their lifetimes, which are essentially cooling times, are short). Three: why short-period novae all decline to luminosity states far above their true quiescence (because they are just getting started in their post-nova cooling). Four: why the orbital periods, accretion rates and white dwarf temperatures of short-period CVs are somewhat too large to arise purely from the effects of gravitational radiation (because the unexpectedly long interval of enhanced post-nova brightness boosts the mean mass-transfer rate). And maybe even five: why very old, post-period-bounce CVs are hard to find (because the higher mass-loss rates have `burned them out'). These are substantial rewards in return for one investment of hypothesis: that the second parameter in CV evolution, besides orbital period, is time since the last classical-nova eruption.

SIMULATIONS OF THE SYMBIOTIC RECURRENT NOVA V407 CYG. I. ACCRETION AND SHOCK EVOLUTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E., E-mail: kuo-chuan.pan@unibas.ch, E-mail: pmricker@illinois.edu, E-mail: r-taam@northwestern.edu, E-mail: taam@asiaa.sinica.edu.tw

2015-06-10

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 anmore » 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{sup −1}, which is consistent with the observed extended redward emission in [N ii] lines in 2011 April.« less

Time-Resolved Photometry of V458 Vul

NASA Astrophysics Data System (ADS)

Bouzid, Samia; Garnavich, P.

2011-01-01

We observed V458 Vul (Nova Vul 2007) over four nights in June, 2010, nearly three years after its nova outburst. Time-resolved photometry was obtained at the Vatican Advanced Technology Telescope (VATT) on Mt. Graham, Arizona, covering 2 to 4 hour spans with a cadence of 30 sec. The first night of data shows a clear 20 minute periodicity with a 0.1 magnitude amplitude. On subsequent nights, power-spectral analysis continues to show variations with a time scale of 20 minutes, but the irregularity of the signal suggests that this is a quasi-periodic oscillation. The 98-minute orbital period is not evident in our observations. V458 Vul is the central star of a planetary nebula. Combining our CCD images suggests a light echo from the nova outburst is scattering off of material in the nebula to the northwest of the central star. Appreciation goes to the National Science Foundation for supporting this project through the Research Experience for Undergraduates program at Notre Dame.

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

2012-02-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

15 CFR 960.15 - Penalties and sanctions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... assessment (NOVA) will be issued by NOAA and served personally or by registered or certified mail, return... conclusions upon which NOAA based the assessment; (iv) The amount of the civil penalty assessed; and (v) An explanation of the licensee's rights upon receipt of the NOVA. (2) In assessing a civil penalty, NOAA will...

15 CFR 960.15 - Penalties and sanctions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... assessment (NOVA) will be issued by NOAA and served personally or by registered or certified mail, return... conclusions upon which NOAA based the assessment; (iv) The amount of the civil penalty assessed; and (v) An explanation of the licensee's rights upon receipt of the NOVA. (2) In assessing a civil penalty, NOAA will...

15 CFR 960.15 - Penalties and sanctions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... assessment (NOVA) will be issued by NOAA and served personally or by registered or certified mail, return... conclusions upon which NOAA based the assessment; (iv) The amount of the civil penalty assessed; and (v) An explanation of the licensee's rights upon receipt of the NOVA. (2) In assessing a civil penalty, NOAA will...

15 CFR 960.15 - Penalties and sanctions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... assessment (NOVA) will be issued by NOAA and served personally or by registered or certified mail, return... conclusions upon which NOAA based the assessment; (iv) The amount of the civil penalty assessed; and (v) An explanation of the licensee's rights upon receipt of the NOVA. (2) In assessing a civil penalty, NOAA will...

Test bench for measurements of NOvA scintillator properties at JINR

NASA Astrophysics Data System (ADS)

Velikanova, D. S.; Antoshkin, A. I.; Anfimov, N. V.; Samoylov, O. B.

2018-04-01

The NOvA experiment was built to study oscillation parameters, mass hierarchy, CP- violation phase in the lepton sector and θ23 octant, via vɛ appearance and vμ disappearance modes in both neutrino and antineutrino beams. These scientific goals require good knowledge about NOvA scintillator basic properties. The new test bench was constructed and upgraded at JINR. The main goal of this bench is to measure scintillator properties (for solid and liquid scintillators), namely α/β discrimination and Birk's coefficients for protons and other hadrons (quenching factors). This knowledge will be crucial for recovering the energy of the hadronic part of neutrino interactions with scintillator nuclei. α/β discrimination was performed on the first version of the bench for LAB-based and NOvA scintillators. It was performed again on the upgraded version of the bench with higher statistic and precision level. Preliminary result of quenching factors for protons was obtained. A technical description of both versions of the bench and current results of the measurements and analysis are presented in this work.

Nova Eruptions from Radio to Gamma-raysówith AAVSO Data in the Middle (Abstract)

NASA Astrophysics Data System (ADS)

Mukai, K.; Kafka, S.; Chomiuk, L.; Li, R.; Finzell, T.; Linford, J.; Sokoloski, J.; Nelson, T.; Rupen, M.; Mioduszewski, A.; Weston, J.

2018-06-01

(Abstract only) Novae are among the longest-known class of optical transients. In recent years, V1369 Cen in the south reached magnitude 3.3 in late 2013, and had repeated (but not periodic) cycles of re-brightening. Earlier in 2013, V339 Del almost reached magnitude 4.0 during the northern summer. An expanding ball of gas, at about 10,000 K, expelled by a nuclear explosion on the surface of a white dwarf, can explain much of the visible light outputs of novae. But these spectacular visible light displays turn out to be just a small part of the show. Novae are also transient objects in the radio through gamma-raysóin addition to the warm, visible light-emitting gas, we need cold dust particles that emit in the infra-red, 10 million degree shock-heated gas that emits hard X-rays, and the exposed surface of the nuclear-burning white dwarf that emits soft X-rays. Last but not least, we need an exotic process of particle acceleration to explain the gamma-rays and some radio data.

Asymmetries in Core-Collapse Supernovae from Maps of Radioactiver 44Ti in Cassiopeia A

NASA Technical Reports Server (NTRS)

Grefenstette, B.W.; Harrison, F. A.; Boggs, S. E.; Reynolds, S. P.; Fryer, C. L.; Madsen, K. K.; Wik, Daniel R.; Zoglauer, A.; Ellinger, C. I.; Alexander, D. M.;

Infrared photometry of the dwarf nova V2051 Ophiuchi - I. The mass-donor star and the distance

NASA Astrophysics Data System (ADS)

Wojcikiewicz, Eduardo; Baptista, Raymundo; Ribeiro, Tiago

2018-04-01

We report the analysis of time series of infrared JHKs photometry of the dwarf nova V2051 Oph in quiescence. We modelled the ellipsoidal variations caused by the distorted mass-donor star to infer its JHKs fluxes. From its infrared colours, we estimate a spectral type of M(8.0 ± 1.5) and an equivalent blackbody temperature of TBB = (2700 ± 270) K. We used the Barnes & Evans relation to infer a photometric parallax distance of dBE = (102 ± 16) pc to the binary. At this short distance, the corresponding accretion disc temperatures in outburst are too low to be explained by the disc-instability model for dwarf nova outbursts, underscoring a previous suggestion that the outbursts of this binary are powered by mass-transfer bursts.

The Origin of X-ray Emission from the Enigmatic Be Star γ Cassiopeiae

NASA Astrophysics Data System (ADS)

Hamaguchi, K.; Oskinova, L.; Russell, C. M. P.; Petre, R.; Enoto, T.; Morihana, K.; Ishida, M.

2017-11-01

Gamma Cassiopeiae is an enigmatic Be star with unusually hard, strong X-ray emission compared with normal main-sequence B stars. The origin has been debated for decades between two theories: mass accretion onto a hidden compact companion and a magnetic dynamo driven by the star-Be disk differential rotation. There has been no decisive signature found that supports either theory, such as a pulse in X-ray emission or the presence of large-scale magnetic field. In a ~100 ksec duration observation of the star with the Suzaku X-ray observatory in 2011, we detected six rapid X-ray spectral hardening events called ``softness dips''. All the softness dip events show symmetric softness ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either ~40% or ~70% partial covering absorption to kT ~12 keV plasma emission by matter with a neutral hydrogen column density of ~2 - 8 × 1021cm-2, while the spectrum outside of these dips is almost free of absorption. This result suggests that two distinct X-ray emitting spots in the γ Cas system, perhaps on a white dwarf companion with dipole mass accretion, are occulted by blobs in the Be stellar wind, the Be disk, or rotating around the white dwarf companion. The formation of a Be star and white dwarf binary system requires mass transfer between two stars; γ Cas may have experienced such activity in the past.

Photometric Investigation and Possible Light-Time Effect in the Orbital Period of a Marginal Contact System, CW Cassiopeiae

NASA Astrophysics Data System (ADS)

Jiang, Tian-Yu; Li, Li-Fang; Han, Zhan-Wen; Jiang, Deng-Kai

2010-04-01

The first complete charge-coupled device (CCD) light curves in B and V passbands of a neglected contact binary system, CW Cassiopeiae (CW Cas), are presented. They were analyzed simultaneously by using the Wilson and Devinney (WD) code (1971, ApJ, 166, 605). The photometric solution indicates that CW Cas is a W-type W UMa system with a mass ratio of m2/m1 2.234, and that it is in a marginal contact state with a contact degree of ˜6.5% and a relatively large temperature difference of ˜327K between its two components. Based on the minimum times collected from the literature, together with the new ones obtained in this study, the orbital period changes of CW Cas were investigated in detail. It was found that a periodical variation overlaps with a secular period decrease in its orbital period. The long-term period decrease with a rate of dP/dt = -3.44 × 10-8d yr-1 can be interpreted either by mass transfer from the more-massive component to the less-massive with a rate of dm2/dt = -3.6 × 10-8M⊙ yr-1, or by mass and angular-momentum losses through magnetic braking due to a magnetic stellar wind. A low-amplitude cyclic variation with a period of T = 63.7 yr might be caused by the light-time effect due to the presence of a third body.

XMM-Newton Proposal 03039101

NASA Astrophysics Data System (ADS)

Hernanz, Margarita

2004-10-01

Two recent galactic novae, V2487 Oph 1998 and V4633 Sgr 1998, have been detec- ted in both soft and hard X-rays with XMM. V2487 Oph showed an iron fluores- cent line only 2.7 yrs after its explosion, a clear signature of the very fast recovery of accretion, and V4633 Sgr displayed hard X-ray emission not clearly attributable to shocked ejecta or accretion. Longer observations are needed to do accurate timing and high resolution spectroscopy, essential to determine the main properties of the underlying cataclysmic variable in V2487 Oph (first nova seen in X-rays prior and after exploding) and to disentangle the origin of the hard X-rays from V4633 Sgr, through an analysis of the chemical compo- sition of the emitting thermal plasma, solar if accretion, non solar if ejecta.

The Early X-ray Emission From V382 Velorum (=Nove Vel 1999): An Internal Shock Model

NASA Technical Reports Server (NTRS)

Mukai, Koji; Ishida, Manabu

2000-01-01

We present the results of ASCA and RXTE observations of the early X-ray emission from the classical nova V382 Velorum. Its ASCA spectrum was hard (kT approximately 10 KeV) with a strong (10(exp 13)/sq cm) intrinsic absorption. In the subsequent RXTE data, the spectra became softer both due to a declining temperature and a diminishing column. We argue that this places the X-ray emission interior to the outermost ejecta produced by V382 Vel in 1999, and therefore must have been the result of a shock internal to the nova ejecta. The weakness of the Fe K.alpha lines probably indicates that the X-ray emitting plasmas are not in ionization equilibrium.

Radio Observations as a Tool to Investigate Shocks and Asymmetries in Accreting White Dwarf Binaries

NASA Astrophysics Data System (ADS)

Weston, Jennifer Helen Seng; E-Nova Project

2017-01-01

In this dissertation, I use radio observations with the Karl G. Jansky Very Large Array (VLA) to reveal that colliding flows within the ejecta from nova explosions can lead to shocks that accelerate particles and produce radio synchrotron emission. In both novae V1723 Aql and V5589 Sgr, radio emission within the first one to two months deviated strongly from the classic thermal model for radio emission from novae. Three years of radio observations of V1723 Aql show that multiple outflows from the system collided to create non-thermal shocks with a brightness temperature of >106 K. After these shocks faded, the radio light curve became roughly consistent with an expanding thermal shell. However, resolved images of V1723 Aql show elongated material that apparently rotates its major axis over the course of 15 months. In the case of nova V5589 Sgr, I show that the early radio emission is dominated by a shock-powered non-thermal flare that produces strong (kTx > 33 keV) X-rays. These findings have important implications for understanding how normal novae generate GeV gamma-rays.Additionally, I present VLA observations of the symbiotic star CH Cyg and two small surveys of symbiotic binaries. Radio observations of CH Cyg tie the ejection of a collimated jet to a change of state in the accretion disk, strengthening the link between bipolar outflows from accreting white dwarfs and other types of accreting compact objects. Next, I use a survey of eleven accretion-driven symbiotic binaries to determine that the radio brightness of a symbiotic system could potentially be used as an indicator of whether it is powered predominantly by shell burning on the surface of the white dwarf or by accretion. This survey also produces the first radio detections of seven of the target systems. In the second survey of seventeen symbiotic binaries, I spatially resolve extended radio emission in several systems for the first time. The results from these surveys provide some support for the model of radio emission where the red giant wind is photoionized by the white dwarf, and suggest that there may be a greater population of radio faint, accretion driven symbiotic systems.

Swift observations of nova V407 Lup: detection of a UV period at 1.1 or 3.6 hours

NASA Astrophysics Data System (ADS)

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

2017-08-01

V407 Lup (also known as Nova Lup 2016 and ASASSN-16kt) was reported to be in outburst on 2016-Sep-24.0 by Stanek et al. (ATel #9538 and ATel #9539). Although Swift observations started 2 days later, the source was too bright at the time for the UVOT to observe, and was not detectable in X-rays by the XRT, before the object came too close to the Sun on 2016-Oct-14 to be safely observed by Swift.

Optical Spectroscopy of TCP J04432130+4721280 (V392 Per) Confirms a Nova Eruption

NASA Astrophysics Data System (ADS)

Wagner, R. M.; Terndrup, D.; Darnley, M. J.; Starrfield, S.; Woodward, C. E.; Henze, M.

2018-04-01

Following reports of a new transient of magnitude 6.2 in Perseus on 2018 April 29.4740 UT discovered by Y. Nakamura designated TCP J04432130+4721280 (http://www.cbat.eps.harvard.edu/unconf/followups/J04432130+4721280.html) and positionally coincident with the previously known U Gem type dwarf nova V392 Per, we obtained an optical spectrum on 2018 April 30.116 UT (range: 396-687 nm; resolution 0.3 nm) with the 2.4 m Hiltner telescope (+OSMOS) of the MDM Observatory on Kitt Peak.

The Shock and Vibration Digest. Volume 15, Number 4

DTIC Science & Technology

1983-04-01

Akust. Zh., 23, pp 716-723. 132. Mozhaev , V.G., "Shear-Wave Convolution in a Layered Piezoelectric-Semiconductor Struc- ture," Sov. Phys. Acoust., 27...Piezoelectric Halfspace," Proc. Royal Soc. London, Ser. A 364, pp 161-179 (1978). 138. Mozhaev , V.G. and Solodov, I. Yu, "Second- Harmonic Generation of

INTEGRAL Studies of Nonthermal Emission From the Supernova Remnants Cassiopeia A, CTA 1, and MSH 11-61A

NASA Technical Reports Server (NTRS)

Sturner, S. J.; Beckmann, V.; Bykov, A.; Lebrun, F.; Terrier, R.

2004-01-01

We present the initial results from our study of the nonthermal continuum emission from the supernova remnants Cassiopeia A, MSB 11-61-4, a d CT-4 1. We used the INTEGRAL Core Program data to conduct this study. During the INTEGRAL mission a significant fraction of the total observing time (e.g. 35% in year one) is allocated to the Core Program and is analyzed under the auspices of the INTEGRAL Science Working Team. We report no statistically significant detections thus far but we will continue to analyze the data as more is taken. The results so far are consistent with previous measurements from e.g. RXTE and ASCA.

Cassiopeia A: Supernova explosion and expansion simulations under strong asymmetry conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakhin, R. A., E-mail: yakhin.rafael@gmail.com; Rozanov, V. B.; Zmitrenko, N. V.

We propose a model for the explosion of a supernova and the expansion of its ejecta in the presence of a strong initial asymmetry (at the explosion time) in the central part of the star (core) and a possible smallscale asymmetry in the peripheral regions. The Chandra and NuSTAR observations of ejecta in the Cassiopeia A supernova remnant are analyzed. Based on our 1D and 2D numerical simulations performed using the DIANA and NUTCY codes, we propose a model for the explosion and expansion of ejecta that explains the observed experimental data where the materials initially located in the centralmore » region of the star end up on the periphery of the cloud of ejecta.« less

Polyp morphogenesis in a scyphozoan: Evidence for a head inhibitor from the presumptive foot end in vegetative buds ofCassiopeia andromeda.

PubMed

Neumann, R

1977-03-01

Buds ofCassiopeia andromeda have been transected into fragments of various sizes. Depending on their original position in the organism, on their size and on the age of the dissected buds, the fragments either regenerated or developed to a solitary polyp's head without stalk and peduncle. Generally, basal fragments tended to regenerate complete buds, young apical parts mostly differenciated polyp heads whereas apical and middle parts of progressively older buds regenerated buds with increasing frequency. To explain the alteration of the developmental capacities a head inhibitor is postulated which originates from the basal end of the buds and which expands towards the apical pole with increasing age of the buds.

Characterization of helium-vacancy complexes in He-ions implanted Fe9Cr by using positron annihilation spectroscopy

NASA Astrophysics Data System (ADS)

Zhu, Te; Jin, Shuoxue; Zhang, Peng; Song, Ligang; Lian, Xiangyu; Fan, Ping; Zhang, Qiaoli; Yuan, Daqing; Wu, Haibiao; Yu, Runsheng; Cao, Xingzhong; Xu, Qiu; Wang, Baoyi

2018-07-01

The formation of helium bubble precursors, i.e., helium-vacancy complexes, was investigated for Fe9Cr alloy, which was uniformly irradiated by using 100 keV helium ions with fluences up to 5 × 1016 ions/cm2 at RT, 523, 623, 723, and 873 K. Helium-irradiation-induced microstructures in the alloy were probed by positron annihilation technique. The results show that the ratio of helium atom to vacancy (m/n) in the irradiation induced HemVn clusters is affected by the irradiation temperature. Irradiated at room temperature, there is a coexistence of large amounts of HemV1 and mono-vacancies in the sample. However, the overpressured HemVn (m > n) clusters or helium bubbles are easily formed by the helium-filled vacancy clusters (HemV1 and HemVn (m ≈ n)) absorbing helium atoms when irradiated at 523 K and 823 K. The results also show that void swelling of the alloy is the largest under 723 K irradiation.

One-Proton Breakup of 18F and the 17O(p,γ)18F Reaction in Classical Novae

NASA Astrophysics Data System (ADS)

Isherwood, Bryan; Banu, A.; E491 Collaboration

2013-10-01

Classical nova studies are of considerable interest for understanding the chemical evolution of the Galaxy. They have been proposed as the most significant source for the nucleosynthesis of the isotopes 13C, 15N, and 17O in the Universe. Novae are also likely to synthesize the short-lived radioisotope 18F (T1/2 = 110 min), which is expected to be the most important contributor to the observed emission of 511 keV gamma radiation by space-based γ-ray telescopes. This emission is produced by electron-positron annihilation following the beta + decay of radioactive nuclei. A detection of these gamma rays could significantly constrain the nova simulation models. 18F nucleosynthesis in classical novae strongly depends on the thermonuclear rate of the 17O(p,γ)18F reaction, which is part of the CNO cycle. This work presents preliminary results toward determination of the 17O(p,γ)18F reaction cross section, which was measured by the indirect method of one-proton nuclear breakup at intermediate energies. The experiment was carried out at GANIL using a beam of 18F at 40 MeV/u impinging on a carbon target. Longitudinal momentum distributions of the 17O breakup fragments were measured in coincidence with γ-rays emitted by 17O residues.

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

NASA Technical Reports Server (NTRS)

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

2012-01-01

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

The SSS classical nova V5116 Sgr

NASA Astrophysics Data System (ADS)

Sala, G.; Ness, J.; Greiner, J.; Hernanz, M.

2017-10-01

XMM-Newton observed the nova V5116 Sgr during its supersoft phase (SSS). V5116 Sgr showed a decrease of the flux by a factor around 8 during 2/3 of the orbital period. The broad band EPIC spectra remain unchanged during the different flux phases, suggesting an occultation of the central source in a high inclination system. While the global SED does not change significantly, the RGS spectrum is changing between the high and the low flux phases. The non-occultation phase shows a typical white dwarf atmosphere spectrum, dominated by absorption lines. During the low flux periods an extra component of emission lines is superimposed to the soft X-ray continuum. This supports the picture of V5116 Sgr as the clearest example of a system switching between the SSa class of SSS novae, with spectra dominated by absorption lines, and the SSe class, showing an emission lines component. In addition, the simultaneous OM images allow us to find a phase solution for the X-ray light-curve. A thick rim of the accretion disk as the one developed for the SSSs CAL 87, RX J0019.8, and RX J0513.9 could provide a plausible model both for the optical and the X-ray light curve of V5116 Sgr.

Measurement of key resonance states for the P 30 ( p , γ ) S 31 reaction rate, and the production of intermediate-mass elements in nova explosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kankainen, A.; Woods, P. J.; Schatz, H.

2017-06-01

We report the first experimental constraints on spectroscopic factors and strengths of key resonances in the P-30(p, gamma)S-31 reaction critical for determining the production of intermediate-mass elements up to Ca in nova ejecta. The P-30(d,n)S-31 reaction was studied in inverse kinematics using the GRETINA gamma-ray array to measure the angle-integrated cross-sections of states above the proton threshold. In general, negative parity states are found to be most strongly produced but the absolute values of spectroscopic factors are typically an order of magnitude lower than predicted by the shell-model calculations employing WBP Hamiltonian for the negative-parity states. The results clearly indicatemore » the dominance of a single 3/2(-) resonance state at 196 keV in the region of nova burning T approximate to 0.10-0.17 GM, well within the region of interest for nova nucleosynthesis. Hydrodynamic simulations of nova explosions have been performed to demonstrate the effect on the composition of nova ejecta.« less

π0 mass reconstruction in NOvA Far Detector.

NASA Astrophysics Data System (ADS)

Edayath, Sijith

2017-01-01

NOvA is a long-baseline neutrino oscillation experiment with functionally identical, segmented, tracking calorimeter Near and Far detectors. The detectors lie 14.6 mrad off-axis from the Fermilab NuMI beam, with a well-defined peak in neutrino energy at 2 GeV. The absolute calibration of the energy scale of the detectors is a major systematic uncertainty in long-baseline oscillation search in NOvA. Neutrino detectors make use of some standard candles for absolute energy calibration. Stopping muon energy distributions, Michel electron energy distributions, and invariant π0 mass are among them. In this talk, we cover NOvA's use of a new method to identify π0 with cosmic origins in the NOvA Far Detector. We employ a computer vision based particle identifier using convolutional neural networks (CVN) to identify π0s, complementing an existing strategy to identify π0 from the neutrino beam using more traditional methods in the Near Detector. Registered for PhD at Cochin University of Science and Technology, India and doing research in NOvA experiment at Fermilab.

Measurement of key resonance states for the 30P (p , γ)31S reaction rate, and the production of intermediate-mass elements in nova explosions

NASA Astrophysics Data System (ADS)

Kankainen, A.; Woods, P. J.; Schatz, H.; Poxon-Pearson, T.; Doherty, D. T.; Bader, V.; Baugher, T.; Bazin, D.; Brown, B. A.; Browne, J.; Estrade, A.; Gade, A.; José, J.; Kontos, A.; Langer, C.; Lotay, G.; Meisel, Z.; Montes, F.; Noji, S.; Nunes, F.; Perdikakis, G.; Pereira, J.; Recchia, F.; Redpath, T.; Stroberg, R.; Scott, M.; Seweryniak, D.; Stevens, J.; Weisshaar, D.; Wimmer, K.; Zegers, R.

2017-06-01

We report the first experimental constraints on spectroscopic factors and strengths of key resonances in the 30P (p , γ)31S reaction critical for determining the production of intermediate-mass elements up to Ca in nova ejecta. The 30P (d , n)31S reaction was studied in inverse kinematics using the GRETINA γ-ray array to measure the angle-integrated cross-sections of states above the proton threshold. In general, negative-parity states are found to be most strongly produced but the absolute values of spectroscopic factors are typically an order of magnitude lower than predicted by the shell-model calculations employing WBP Hamiltonian for the negative-parity states. The results clearly indicate the dominance of a single 3 /2- resonance state at 196 keV in the region of nova burning T ≈ 0.10- 0.17 GK, well within the region of interest for nova nucleosynthesis. Hydrodynamic simulations of nova explosions have been performed to demonstrate the effect on the composition of nova ejecta.

High-energy Emission from Nonrelativistic Radiative Shocks: Application to Gamma-Ray Novae

NASA Astrophysics Data System (ADS)

Vurm, Indrek; Metzger, Brian D.

2018-01-01

The observation of GeV gamma-rays from novae by Fermi/LAT demonstrates that the nonrelativistic radiative shocks in these systems can accelerate particles to energies of at least ∼10 GeV. The low-energy extension of the same nonthermal particle distribution inevitably gives rise to emission in the hard X-ray band. Above ≳ 10 {keV}, this radiation can escape the system without significant absorption/attenuation, and can potentially be detected by NuSTAR. We present theoretical models for hard X-ray and gamma-ray emission from radiative shocks in both leptonic and hadronic scenarios, accounting for the rapid evolution of the downstream properties due to the fast cooling of thermal plasma. We find that due to strong Coulomb losses, only a fraction of {10}-4{--}{10}-3 of the gamma-ray luminosity is radiated in the NuSTAR band; nevertheless, this emission could be detectable simultaneously with the LAT emission in bright gamma-ray novae with a ∼50 ks exposure. The spectral slope in hard X-rays is α ≈ 0 for typical nova parameters, thus serving as a testable prediction of the model. Our work demonstrates how combined hard X-ray and gamma-ray observations can be used to constrain properties of the nova outflow (velocity, density, and mass outflow rate) and particle acceleration at the shock. A very low X-ray to gamma-ray luminosity ratio ({L}{{X}}/{L}γ ≲ 5× {10}-4) would disfavor leptonic models for the gamma-ray emission. Our model can also be applied to other astrophysical environments with radiative shocks, including SNe IIn and colliding winds in massive star binaries.

An X-ray halo around Cassiopeia A

NASA Astrophysics Data System (ADS)

Stewart, G. C.; Fabian, A. C.; Seward, F. D.

The large-scale X-ray emission of Cas A is characterized, and mechanisms are proposed to explain it. The Einstein HRI image of Murray et al. (1979) is binned into 16-arcsec pixels, a point-spread function based on the 2.04-keV monochromatic Zr source is applied, and the data are modeled as a series of circularly symmetric rings of emission. A significant excess extending to a radius of 6 arcmin (roughly the size of the optical H II region) is found to have a total 0.5-3-keV luminosity of about 5 x 10 to the 34th erg/s, or about 2 percent of the total luminosity of Cas A, which is assumed to lie at a distance of 3 kpc. Thermal bremsstrahlung, synchrotron radiation, and dust scattering of the main-shell emission are examined and found to be plausible emission mechanisms; further observations are required to identify the one active in Cas A.

Follow-up Observations of SDSS and CRTS Candidate Cataclysmic Variables II

NASA Astrophysics Data System (ADS)

Szkody, Paula; Everett, Mark E.; Dai, Zhibin; Serna-Grey, Donald

2018-01-01

Spectra of 38 candidate or known cataclysmic variables are presented. Most are candidate dwarf novae or systems containing possible highly magnetic white dwarfs, while a few (KR Aur, LS Peg, V380 Oph, and V694 Mon) are previously known objects caught in unusual states. Individual spectra are used to confirm a dwarf nova nature or other classification while radial velocities of 15 systems provide orbital periods and velocity amplitudes that aid in determining the nature of the objects. Our results substantiate a polar nature for four objects, find an eclipsing SW Sex star below the period gap, another as a likely intermediate polar, as well as two dwarf novae with periods in the middle of the gap. Based on observations obtained with the Apache Point Observatory (APO) 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium (ARC).

V1494 Aql: Eclipsing Fast Nova with an Unusual Orbital Light Curve

NASA Astrophysics Data System (ADS)

Kato, Taichi; Ishioka, Ryoko; Uemura, Makoto; Starkey, Donn R.; Krajci, Tom

2004-03-01

We present the time-resolved photometry of V1494 Aql (Nova Aql 1999 No. 2) between 2001 November and 2003 June. The object is confirmed to be an eclipsing nova with a period of 0.1346138(2)d. The eclipses were present in all observed epochs. The orbital light curve shows a rather unusual profile, consisting of a bump-like feature at phase 0.6-0.7 and a dip-like feature at phase 0.2-0.4. These features were probably persistently present in all available observations between 2001 and 2003. A period analysis outside of the eclipses has confirmed that these variations have a period common to the orbital period, and are unlikely to be interpreted as superhumps. We suspect that the structure (probably in the accretion disk) fixed in the binary rotational frame is somehow responsible for this feature.

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.;

Searches for sterile neutrinos with NOvA

DOE PAGES

Davies, Gavin S.; Aurisano, Adam; Kafka, Gareth K.; ...

2016-11-15

Contradictory evidence has been presented on the issue of neutrino mixing between the three known active neutrinos and light sterile neutrino species. Apparent short-baseline neutrino oscillations observed by the LSND and MiniBooNE experiments, the collective evidence of the reactor neutrino anomaly, and the gallium anomaly all point towards sterile neutrinos with mass at the 1 eV level. While these results are tantalizing, they are not conclusive as they are in tension with null results from other short-baseline experiments, and with disappearance searches in longbaseline and atmospheric experiments. The NOvA (NuMI Off-Axis v e Appearance) experiment may help clarify the situationmore » by searching for disappearance of active neutrinos from the NuMI (Neutrinos from the Main Injector) beam over a baseline of 810 km. We describe the method used by NOvA to look for oscillations into sterile neutrinos at the Far Detector (FD) through the disappearance of neutral-current (NC) neutrino events, including preliminary results of this search. In addition, the Near Detector (ND) is well suited for searching for anomalous short-baseline oscillations and probing the LSND and MiniBooNE sterile neutrino allowed regions using a variety of final states. We also present a novel method for selecting samples with high purity at the ND using convolutional neural networks. Furthermore, based on this method, the sensitivity to anomalous short-baseline nt appearance are shown, and searches for anomalous v e appearance and v μ disappearance at the NOvA ND are presented.« less

Discrepancies between knowledge and practice of childhood motor vehicle occupant safety in Nova Scotia--a population-based study.

PubMed

Yanchar, Natalie L; Kirkland, Susan A; LeBlanc, John C; Langille, Donald B

2012-03-01

To determine discrepancies between knowledge and practice of childhood motor vehicle restraints (CMVRs) and vehicle seating position amongst parents within the province of Nova Scotia. Random telephone survey. The Canadian province of Nova Scotia. Four hundred and twenty-six households with at least one child under the age of 12 years, totaling 723 children. The proportion of parents whose children who should be in a specific stage of CMVR and sitting in the rear seat of the vehicle, and who demonstrate correct knowledge of that restraint system and seating position, yet do not use that restraint system/seating position for their child (demonstrate practice discrepant from their knowledge). Awareness of what restraint system to use is good (>80%). However, knowledge of when it is safe to graduate to the next stage is low (30-55%), most marked for when to use a seatbelt alone. Awareness of the importance of sitting in the rear seat of a vehicle was universal. Discrepancies between knowledge and practice were most marked with booster seats and rear-seating of older children. Factors influencing incorrect practice (prematurely graduated to a higher-level restraint system than what is appropriate for age and weight) included lower household income, caregiver education level, and knowledge of when to graduate from forward-facing car seats and booster seats. Incorrect practice was also more commonly observed amongst children of weight and/or age approaching (but not yet reaching) recommended graduation parameters of the appropriate CMVR. Discrepancies between knowledge and practice are evident through all stages of CMVRs, but most marked with booster seats. The roles of lower socioeconomic status and gaps in CMVR legislation, in influencing discrepant practice, must be acknowledged and suggest the need for targeted education concurrent with development of comprehensive all-stages CMVR policies. Copyright © 2011 Elsevier Ltd. All rights reserved.

First spin-parity constraint of the 306 keV resonance in Cl 35 for nova nucleosynthesis

DOE PAGES

Chipps, K. A.; Rutgers Univ., New Brunswick, NJ; Pain, S. D.; ...

2017-04-28

Something of particular interest in astrophysics is the 34 S ( p , γ ) 35 Cl reaction, which serves as a stepping stone in thermonuclear runaway reaction chains during a nova explosion. Although the isotopes involved are all stable, the reaction rate of this significant step is not well known, due to a lack of experimental spectroscopic information on states within the Gamow window above the proton separation threshold of 35 Cl . Furthermore, measurements of level spins and parities provide input for the calculation of resonance strengths, which ultimately determine the astrophysical reaction rate of the 34 Smore » ( p , γ ) 35 Cl proton capture reaction. By performing the 37 Cl ( p , t ) 35 Cl reaction in normal kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, we have conducted a study of the region of astrophysical interest in 35 Cl , and have made the first-ever constraint on the spin and parity assignment for a level at 6677 ± 15 keV ( E r = 306 keV), inside the Gamow window for novae.« less

First spin-parity constraint of the 306 keV resonance in 35Cl for nova nucleosynthesis

NASA Astrophysics Data System (ADS)

Chipps, K. A.; Pain, S. D.; Kozub, R. L.; Bardayan, D. W.; Cizewski, J. A.; Chae, K. Y.; Liang, J. F.; Matei, C.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Peters, W. A.; Pittman, S. T.; Schmitt, K. T.; Smith, M. S.

2017-04-01

Of particular interest in astrophysics is the 34S(p ,γ )35Cl reaction, which serves as a stepping stone in thermonuclear runaway reaction chains during a nova explosion. Though the isotopes involved are all stable, the reaction rate of this significant step is not well known, due to a lack of experimental spectroscopic information on states within the Gamow window above the proton separation threshold of 35Cl. Measurements of level spins and parities provide input for the calculation of resonance strengths, which ultimately determine the astrophysical reaction rate of the 34S(p ,γ )35Cl proton capture reaction. By performing the 37Cl(p ,t )35Cl reaction in normal kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, we have conducted a study of the region of astrophysical interest in 35Cl, and have made the first-ever constraint on the spin and parity assignment for a level at 6677 ±15 keV (Er=306 keV), inside the Gamow window for novae.

The Use of the BAT Instrument on SWIFT for the Detection of Prompt Gamma-Ray Emission from Novae

NASA Technical Reports Server (NTRS)

Skinner, Gerry; Senziani, Fabio; Jean, Pierre; Hernanz, Margarita

2007-01-01

Gamma-rays are expected to be emitted during and immediately following a nova explosion due to the annihilation of positrons emitted by freshly produced short-lived radioactive isotopes. The expected gammaray emission is relatively short-lived and as nova explosions are unpredictable, the best chance of detecting the gamma-rays is with n wide field instrument. At the time when the flux is expected to rcach its peak, most of the gamma-ray production is at depths such that the photons suffer several Compton scatterings before escaping, degrading their energy down to the hard X-ray band (10s of keV). SWIFT/BAT is a very wide field coded mask instrument working in the energy band 14-190 keV and so is very well suited to the search for such gamma-rays. A retrospective search is being made in the BAT data for evidence for gamma-ray emission from the direction of novae at around the time of their explosion. So far the only positive detection is of RS Ophiuchi and in this case the emission is probably due to shock heating.

Nova Sagittarii 2014 = PNV J18250860-2236024 AND Erratum

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2014-02-01

Details of discovery of Nova Sagittarii 2014 (PNV J18250860-2236024) and procedures for observing and reporting observations are announced. Discovered by Sigeru Furuyama (Tone-machi, Ibaraki-ken, Japan) andreported by S. Nakano (Sumoto, Japan) at unfiltered CCD magnitude 8.7 on 2014 Jan. 26.857 UT. Coordinates: R.A. 18 25 08.60 Decl. = -22 36 02.4 (2000.0). Nova Sgr 2014 is Fe II-type classical nova past maximum, per low-resolution spectra obtained by A. Arai on 2014 Jan. 30.87 UT. Announced in IAU CBAT CBET 3802 (D. 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. Also, an Erratum is reported. In AAVSO Alert Notice 496, Mati Morel (MMAT, Thornton, NSW, Australia) was credited with the discovery of the 1989 outburst of V745 Sco. The discoverer was William Liller (LIW, Vina del Mar, Chile), who observed V745 Sco on 1989 July 30.08 UT at magnitude 9.7 (PROBLICOM discovery using 2415 film with orange filter).

Dead Star Rumbles

NASA Image and Video Library

2005-06-10

This Spitzer Space Telescope composite shows the supernova remnant Cassiopeia A white ball and surrounding clouds of dust gray, orange and blue. It consists of two processed images taken one year apart.

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.

Time Series Model Identification and Prediction Variance Horizon.

DTIC Science & Technology

1980-06-01

stationary time series Y(t). -6- In terms of p(v), the definition of the three time series memory types is: No Memory Short Memory Long Memory X IP (v)I 0 0...X lp(v)l < - I IP (v) = v=1 v=l v=l Within short memory time series there are three types whose classification in terms of correlation functions is...1974) "Some Recent Advances in Time Series Modeling", TEEE Transactions on Automatic ControZ, VoZ . AC-19, No. 6, December, 723-730. Parzen, E. (1976) "An

Experimental measurements of hydrodynamic instabilities on NOVA of relevance to astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budil, K S; Cherfils, C; Drake, R P

1998-09-11

Large lasers such as Nova allow the possibility of achieving regimes of high energy densities in plasmas of millimeter spatial scales and nanosecond time scales. In those plasmas where thermal conductivity and viscosity do not play a significant role, the hydrodynamic evolution is suitable for benchmarking hydrodynamics modeling in astrophysical codes. Several experiments on Nova examine hydrodynamically unstable interfaces. A typical Nova experiment uses a gold millimeter-scale hohlraum to convert the laser energy to a 200 eV blackbody source lasting about a nanosecond. The x-rays ablate a planar target, generating a series of shocks and accelerating the target. The evolvingmore » area1 density is diagnosed by time-resolved radiography, using a second x-ray source. Data from several experiments are presented and diagnostic techniques are discussed.« less

A Royal Celebration

NASA Image and Video Library

2012-01-10

This enormous section of the Milky Way galaxy is a mosaic of images from NASA Wide-field Infrared Survey Explorer. The constellations Cassiopeia and Cepheus are featured in this 1,000-square degree expanse.

Synthetic Spectral Analysis of the Far Ultraviolet Spectra of the Old Nova HR Del

NASA Astrophysics Data System (ADS)

Robertson, Jordan; Sion, E.

2012-05-01

We present a synthetic spectral analysis of the archival IUE far ultraviolet spectra of the post-nova, HR Del (Nova Del 1967). The system has an estimated white dwarf mass of 0.55 Msun (Ritter and Kolb 2003), orbital period P_orb = 0.214165 days, estimated orbital inclination of 40 degrees (Keurster 1988) and distance determinations in the literature ranging from 970 pc to 285 pc. The spectra reveal P Cygni profiles indicative of wind outflow from the disk and closely resemble the IUE spectra of UX UMa nova-likes, which have never had recorded outbursts. We de-reddened the archival IUE spectra using E(B-V) = 0.16. Our synthetic spectral analysis utilized optically thick, steady state accretion disk models and white dwarf model atmospheres that we constructed using TLUSTY and SYNSPEC (Hubeny 1988, Hubeny and Lanz (1995). Our input parameters were the white dwarf mass, inclination and a range of accretion rates for which we found the best-fitting model. We report the results of our model fitting and compare HR Del with other post-novae at comparable times past their nova outburst. This work was supported by NSF grant 0807892 to Villanova University

X-ray Modeling of Classical Novae

NASA Astrophysics Data System (ADS)

Nemeth, Peter

2010-01-01

It has been observed and theoretically supported in the last decade that the peak of the spectral energy distribution of classical novae gradually shifts to higher energies at constant bolometric luminosity after a nova event. For this reason, comprehensive evolutionary studies require spectral analysis in multiple spectral bands. After a nova explosion, the white dwarf can maintain stable surface hydrogen burning, the duration of which strongly correlates with the white dwarf mass. During this stage the peak of the luminosity is in the soft X-ray band (15 - 60 Angstroms). By extending the modeling range of TLUSTY/SYNSPEC, I analyse the luminosity and abundance evolution of classical novae. Model atoms required for this work were built using atomic data from NIST/ASD and TOPBASE. The accurate but incomplete set of energy levels and radiative transitions in NIST were completed with calculated data from TOPBASE. Synthetic spectra were then compared to observed data to derive stellar parameters. I show the capabilities and validity of this project on the example of V4743 Sgr. This nova was observed with both Chandra and XMM-Newton observatories and has already been modeled by several scientific groups (PHOENIX, TMAP).

LACERTA I AND CASSIOPEIA III. TWO LUMINOUS AND DISTANT ANDROMEDA SATELLITE DWARF GALAXIES FOUND IN THE 3{pi} PAN-STARRS1 SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Nicolas F.; Laevens, Benjamin P. M.; Slater, Colin T.

We report the discovery of two new dwarf galaxies, Lacerta I/Andromeda XXXI (Lac I/And XXXI) and Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), in stacked Pan-STARRS1 r{sub P1}- and i{sub P1}-band imaging data. Both are luminous systems (M{sub V} {approx} -12) located at projected distances of 20. Degree-Sign 3 and 10. Degree-Sign 5 from M31. Lac I and Cas III are likely satellites of the Andromeda galaxy with heliocentric distances of 756{sup +44}{sub -28} kpc and 772{sup +61}{sub -56} kpc, respectively, and corresponding M31-centric distances of 275 {+-} 7 kpc and 144{sup +6}{sub -4} kpc. The brightest of recent Local Groupmore » member discoveries, these two new dwarf galaxies owe their late discovery to their large sizes (r{sub h} = 4.2{sup +0.4}{sub -0.5} arcmin or 912{sup +124}{sub -93} pc for Lac I; r{sub h} = 6.5{sup +1.2}{sub -1.0} arcmin or 1456 {+-} 267 pc for Cas III) and consequently low surface brightness ({mu}{sub 0} {approx} 26.0 mag arcsec{sup -2}), as well as to the lack of a systematic survey of regions at large radii from M31, close to the Galactic plane. This latter limitation is now alleviated by the 3{pi} Pan-STARRS1 survey, which could lead to the discovery of other distant Andromeda satellite dwarf galaxies.« less

The Evolution of NR TrA (Nova TrA 2008) from 2008 through 2017

NASA Astrophysics Data System (ADS)

Walter, Frederick M.; Burwitz, Vadim; Kafka, Stella

2018-06-01

The classical nova NR TrA was discovered as an O-type optically-thick classical nova. There is no evidence that it formed dust. Within four years the envelope became sufficiently thin to reveal an eclipsing accretion disk-dominated system with orbitally-modulated permitted lines of C IV, N V, and O VI. XMM observations reveal a non-eclipsing soft X-ray source and a deeply-eclipsing UV continuum. We will present the first ten years of optical spectral evolution of this system accompanied by ten years of BVRIJHK photometry, with an eye to deciphering the current nature of the system.

Request to monitor 0103+59 HT Cas, 0809-76 Z Cha, 1004-69 OY Car AND Request to monitor 2147+13 LS Peg AND Request to monitor 1743-12 V378 Ser (Nova Ser 2005)

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2005-06-01

AAVSO Alert Notice 317 has three topics. First: Drs. Christopher Mauche (Lawrence Livermore National Laboratory), Peter Wheatley (Univ. of Leicester), and Koji Mukai (NASA GSFC) have obtained time on XMM-Newton to observe HT Cas, Z Cha, or OY Car in outburst. AAVSO assistance is requested in monitoring these stars closely so we can inform them promptly when any of them go into outburst. Very prompt notification is essential, because the satellite requires 2-4 days to move to the target after the observations are triggered, and the superoutbursts of OY Car and Z Cha last only about 10 days, while the HT Cas outbursts last only a little more than 2 days. Second: Dr. Darren Baskill (Univ. of Leicester) has requested optical observations of LS Peg (currently suspected as being a DQ Her nova-like) to coincide with upcoming observations by XMM-Newton. Observations are requested from now until July 8, with time series 12 hours before and after, and also during the XMM observation. Use an Ic or V filter (Ic preferred), maximum time precision, S/N=100. Third: Dr. Alon Retter (Penn State Univ.) has requested AAVSO assistance in observing V378 Ser (Nova Serpentis 2005). Please monitor V378 Ser over the coming weeks as the nova fades and report your observations to the AAVSO. Both visual and CCD observations are encouraged. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

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 this result is that the nova rate for our Milky Way has doubled.

Does Pacman Have Teeth?

NASA Image and Video Library

2011-10-26

NASA Wide-field Infrared Survey Explorer observed the star-forming cloud NGC 281 in the constellation of Cassiopeia as it appears to be chomping through the cosmos, earning it the nickname the Pacman nebula.

Once an Onion, Always an Onion (Artist Concept)

NASA Technical Reports Server (NTRS)

2006-01-01

This artist's concept illustrates a massive star before and after it blew up in a cataclysmic 'supernova' explosion. NASA's Spitzer Space Telescope found evidence that this star -- the remains of which are named Cassiopeia A -- exploded with some degree of order, preserving chunks of its onion-like layers as it blasted apart.

Cassiopeia A is located 10,000 light-years away in the constellation Cassiopeia. It was once a massive star 15 to 20 times larger than our sun. Its fiery death would have been viewable from Earth about 340 years ago.

The top figure shows the star before it died, when its layers of elements were stacked neatly, with the heaviest at the core and the lightest at the top. Spitzer found evidence that these layers were preserved when the star exploded, flinging outward in all directions, but not at the same speeds. As a result, some chunks of the layered material traveled farther out than others, as illustrated in the bottom drawing.

The infrared observatory was able to see the tossed-out layers, because they light up upon ramming into a 'reverse' shock wave created in the aftermath of the explosion. When a massive star explodes, it creates two types of shock waves. The forward shock wave darts out quickest, and, in the case of Cassiopeia A, is now traveling at supersonic speeds up to 7,500 kilometers per second (4,600 miles/second). The reverse shock wave is produced when the forward shock wave slams into a shell of surrounding material expelled before the star died. It tags along behind the forward shock wave at slightly slower speeds.

Chunks of the star that were thrown out fastest hit the shock wave sooner and have had more time to heat up to scorching temperatures previously detected by X-ray and visible-light telescopes. Chunks of the star that lagged behind hit the shock wave later, so they are cooler and radiate infrared light that was not seen until Spitzer came along. These lagging chunks are made up of gas and dust containing neon, oxygen and aluminum -- elements from the middle layers of the original star.

Radio Observations as a Tool to Investigate Shocks and Asymmetries in Accreting White Dwarf Binaries

NASA Astrophysics Data System (ADS)

Weston, Jennifer H. S.

2016-07-01

This dissertation uses radio observations with the Karl G. Jansky Very Large Array (VLA) to investigate the mechanisms that power and shape accreting white dwarfs (WD) and their ejecta. We test the predictions of both simple spherical and steady-state radio emission models by examining nova V1723 Aql, nova V5589 Sgr, symbiotic CH Cyg, and two small surveys of symbiotic binaries. First, we highlight classical nova V1723 Aql with three years of radio observations alongside optical and X-ray observations. We use these observations to show that multiple outflows from the system collided to create early non-thermal shocks with a brightness temperature of ≥106 K. While the late-time radio light curve is roughly consistent an expanding thermal shell of mass 2x10-4 M⊙ solar masses, resolved images of V1723 Aql show elongated material that apparently rotates its major axis over the course of 15 months, much like what is seen in gamma-ray producing nova V959 Mon, suggesting similar structures in the two systems. Next, we examine nova V5589 Sgr, where we find that the early radio emission is dominated by a shock-powered non-thermal flare that produces strong (kTx > 33 keV) X-rays. We additionally find roughly 10-5 M⊙ solar masses of thermal bremsstrahlung emitting material, all at a distance of ~4 kpc. The similarities in the evolution of both V1723 Aql and V5589 Sgr to that of nova V959 Mon suggest that these systems may all have dense equatorial tori shaping faster flows at their poles. Turning our focus to symbiotic binaries, we first use our radio observations of CH Cyg to link the ejection of a collimated jet to a change of state in the accretion disk. We additionally estimate the amount of mass ejected during this period (10-7 M⊙ masses), and improve measurements of the period of jet precession (P=12013 ± 74 days). We then use our survey of eleven accretion-driven symbiotic systems to determine that the radio brightness of a symbiotic system could potentially be used as an indicator of w hether a symbiotic is powered predominantly by shell burning on the surface of the WD or by accretion. We additionally make the first ever radio detections of seven of the targets in our survey. Our survey of seventeen radio bright symbiotics, comparing observations before and after the upgrades to the VLA, shows the technological feasibility to resolve the nebulae of nearby symbiotic binaries, opening the door for new lines of research. We spatially resolve extended structure in several symbiotic systems in radio for the first time. Additionally, our observations reveal extreme radio variability in symbiotic BF Cyg before and after the production of a jet from the system. Our results from our surveys of symbiotics provide some support for the model of radio emission where the red giant wind is photoionized by the WD, and suggests that there may be a greater population of radio faint, accretion driven symbiotic systems. This work emphasizes the powerful nature of radio observations as a tool for understanding eruptive WD binaries and their outflows.

X-ray Novae and Related Systems

NASA Technical Reports Server (NTRS)

Wheeler, J. Craig; Kim, Soonwook; Mineshige, Shin

1992-01-01

Accretion disk thermal instability models have been successful in accounting for the basic observations of dwarf novae and the steady behavior of nova-like systems. Models for the dwarf-nova like variability of the old nova and intermediate polar GK Per give good agreement with the burst amplitude, profile and recurrence time in the optical and UV. A month-long 'precursor plateau' in the UV is predicted for the expected 1992 outburst prior to the rise to maximum in the optical and UV. The models for the time scales of the outbursts and corresponding UV spectra at maximum are consistent with the inner edge of the accretion disk being essentially constant between quiescence and outburst and a factor of four larger than the co-rotation radius. These conclusions represent a challenge to the standard theory of magnetic accretion. Disk instability models have also given a good representation of the soft X-ray and optical outbursts of the X-ray novae A0620-00 and GS2000+25. Formation of coronae above the disk, heated by magneto-acoustic flux from the disk, may account for the temporal and spectral properties of the hard X-ray and gamma ray emission of related sources such as Cyg X-1, GS 2023+33 (V404 Cyg), IE 1740.7-2942 (the 'Galactic Center' Einstein Source), and GS 1124-683 (Nova Muscae).

The 26gAl(p,g)27Si reaction in Novae

NASA Astrophysics Data System (ADS)

Ruiz, Chris; Parikh, A.; José, J.; Buchmann, L.; Caggiano, J. A.; Chen, A. A.; Clark, J. A.; Crawford, H.; Davids, B.; D'Auria, J. M.; Davis, C.; Deibel, C.; Erikson, L.; Fogarty, L.; Frekers, D.; Greife, U.; Hussein, A.; Hutcheon, D. A.; Huyse, M.; Jewett, C.; Laird, A. M.; Lewis, R.; Mumby-Croft, P.; Olin, A.; Ottewell, D. F.; Ouellet, C. V.; Parker, P.; Pearson, J.; Ruprecht, G.; Trinczek, M.; Vockenhuber, C.; Wrede, C.

The 26gAl(p,γ)27Si Reaction in Novae PoS(NIC-IX)004 1 TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada 2 Wright Nuclear Structure Laboratory, Yale University, New Haven, Conneticut 06520-8124, USA 3 Dept. de Física í Enginyeria Nuclear, Universitat Politécnica de Catalunya, Barcelona, Spain 4 Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain 5 McMaster University, Hamilton, ON L8S 481, Canada 6 Simon Fraser University, Burnaby, BC V5A 1S6, Canada 7 Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA 8 National University of Ireland, Maynooth, Co. Kildare, Ireland 9 Institut für Kernphysik, Westfälische Willhelms-Universität Münster, 48149 Münster, Germany 10 University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada 11 Katholieke Universiteit Leuven, 3000 Leuven, Belgium 12 Department of Physics, University of York, York YO10 5DD, United Kingdom The 184 keV resonance strength in the 26gAl(p,γ)27Si reaction was measured in inverse kinematics using the DRAGON facility at TRIUMF-ISAC. We obtain a value of ωγ=35±7 μeV for the strength and ER=184±1 keV for the resonance energy. These values are consistent with p-wave capture into the 7652(3) keV state in 27Si. We discuss the implications of these results for 26gAl nucleosynthesis in a typical O-Ne white dwarf nova.

AGILE detection of prolonged gamma-ray emission from the Galactic Nova ASASSN-18fv

NASA Astrophysics Data System (ADS)

Piano, G.; Lucarelli, F.; Pittori, C.; Verrecchia, F.; Tavani, M.; Bulgarelli, A.; Parmiggiani, N.; Cardillo, M.; Ursi, A.; Minervini, G.; Donnarumma, I.; Vercellone, S.; Fioretti, V.; Pilia, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Ferrari, A.; Colafrancesco, S.; Paoletti, F.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

2018-04-01

AGILE detected intense gamma-ray emission above 100 MeV from a source at Galactic coordinates (l, b) = (287.08, -1.08) +/- 0.6 deg (68% stat. c.l.) +/- 0.1 deg (syst.) (R.A., Dec. = 159.94, -59.84 deg, J2000), positionally consistent with the Galactic Nova ASASSN-18fv, previously reported in a gamma-ray flaring state by Fermi-LAT (ATel #11546).

Measurement of radiative proton capture on F 18 and implications for oxygen-neon novae reexamined

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akers, C.; Laird, A. M.; Fulton, B. R.

The rate of the F-18(p, gamma)Ne-19 reaction affects the final abundance of the gamma-ray observable radioisotope F-18, produced in novae. However, no successful measurement of this reaction exists and the rate used is calculated from incomplete information on the contributing resonances. Of the two resonances thought to play a significant role, one has a radiative width estimated from the assumed analogue state in the mirror nucleus, F-19. The second does not have an analogue state assignment at all, resulting in an arbitrary radiative width being assumed. Here, we report the first successful direct measurement of the F-18(p, gamma)Ne-19 reaction. Themore » strength of the 665 keV resonance (E-x = 7.076 MeV) is found to be over an order of magnitude weaker than currently assumed in nova models. Reaction rate calculations show that this resonance therefore plays no significant role in the destruction of F-18 at any astrophysical energy.« less

CI Aql monitoring needed to support HST observations

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2016-10-01

Dr. Edward Sion (Villanova University) has requested AAVSO observers' assistance in monitoring the recurrent nova CI Aql in support of observations with the Hubble Space Telescope Cosmic Origins Spectrograph scheduled for October 31 - November 2, 2016, and November 3 - November 5, 2016. These observations are part of a study on short orbital period recurrent novae as Supernovae Type Ia progenitors. It is essential to know 24 hours prior to the HST COS observations that CI Aql is not in outburst, in order to protect the instrumentation. Observers are asked to keep an eye on CI Aql with nightly snapshot images (V preferred) from now until November 12, and to report their observations promptly. It will be especially important to know the brightness of CI Aql each night for October 28 through November 7 UT. Visual observations are welcome. CI Aql (Nova Aql 1917) has had recurrent outbursts in 1941 and 2000, brightening to V 8.5. At minimum it is V 16-16.5 or fainter. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

A White Dwarf at the Limit: V838 Herculis 25 Years After Its Nova Outburst

NASA Astrophysics Data System (ADS)

Garnavich, Peter; Kennedy, Mark; Littlefield, Colin; Szkody, Paula; Mukadam, Anjum

2018-01-01

We present time-resolved photometry and spectroscopy of V838 Her (aka Nova Herculis 1991) a quarter of a century after its unique nova outburst. No new optical observations of the star have been published since the early 1990s. Here, we confirm the presence of deep primary eclipses with a period of 7.14 hours and we detect clear secondary minima. Night-to-night changes of 30% in the system brightness suggests the mass transfer rate is not stable. Spectroscopy reveals absorption features from the secondary star consistent with a K4±1.5 spectral type. From the velocity amplitudes we directly measure the mass ratio of the binary to be q=0.73±0.04. Assuming the secondary is filling its Roche lobe, we estimate the white dwarf mass to be 1.38±0.13 M⊙, consistent with the indirect mass indicators such as the early light curve decay rate and metal abundance in the nebular phase. The mass of the secondary star is also quite high at 1.01±0.06 M⊙. We estimate that the luminosity of the nova peaked at MV = –9.1±0.4 mag, and that its current luminosity is MV = 6.5±0.4 mag.

β-delayed p-decay of proton-rich nuclei ^23Al and ^31Cl and explosive H-burning in novae

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; McCleskey, M.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Aysto, J.; Jokinen, A.; Saastamoinen, A.; Davinson, T.; Woods, P. J.; Achouri, L.; Roeder, B.

2008-10-01

We developed a technique to measure β-delayed proton-decay of proton-rich nuclei produced and separated with MARS at TAMU. In particular, we studied the decay of ^23Al and ^31Cl, both important for understanding explosive H-burning in novae. We have pulsed the beam, implanting the source nuclei moving at about 40 MeV/u in a thin Si strip detector, and then measured β-p and β-γ coincidences simultaneously. The states populated above the proton threshold in ^23Mg and ^31S, respectively, may proton decay. They are resonances in the reaction ^22Na(p,γ)^23Mg (crucial for the depletion of ^22Na in ONe novae) and in ^30P(p,γ)^31S (critical point in explosive H-burning in novae), but the protons emitted have very low energies, starting at about 200 keV, an experimental challenge. The setup and the results are described. The β-decay schemes were established for both nuclei, and IAS identified. The technique has shown a remarkable selectivity to β-delayed charged particle emission and shown to work even at radioactive beam rates of a few pps, for rare isotopes with lifetimes as low as 10s msec.

Testing Cataclysmic Variable Evolution Models with Light Curves of >10,000 Magnitudes Over >100 years and Fully-Corrected to Johnson B & V

NASA Astrophysics Data System (ADS)

Schaefer, Bradley E.

2014-06-01

A combination of magnitudes from the Harvard and Sonneberg plates stacks and the AAVSO data base can create very well-sampled light curves with >10,000 magnitudes and covering all of 1890-2014 for roughly a hundred cataclysmic variables (CVs; novae, novalikes, and dwarf novae). Care must be taken to get all these magnitudes into a modern magnitude system. For the archival plates, these are all close to the B magnitude system so that color terms are small, hence, with the use of modern B magnitudes for the comparison stars, these magnitudes can all be placed onto the Johnson B system. For the archival visual observations, the original comparison sequences can always be found, and the magnitudes for the CV and comparisons must be converted from visual to V, so that the reported magnitudes can be fully corrected to Johnson V. The uncertainties from the plates and the visual magnitudes can always be beaten down by daily or yearly averaging to typical real total error bars of ±0.03 mag, and these are always much smaller than the sampling error arising from flickering and greatly smaller than the range of variations. These very-well-sampled >100 year Johnson B & V light curves can be used to test long term evolution models for CVs. With colleagues, I have made light curves for old novae (GK Per from 1890-2014 with 47,000 mags, V603 Aql from 1898-2014 using 22,722 mags, Q Cyg from 1876-2014 with 6400 mags, T CrB from 1855-2014 using 104,000 mags), Z Cam stars (Z Cam from 1923-2014 with 90,000 mags), and dwarf novae (SS Cyg from 1896-2014 with 403,800 mags). The relative accretion rate is given by both the average flux and by the inverse of the average peak-to-peak time for the dwarf novae. By this means, I have measured the changes in the accretion rate for many CVs and how they change on a yearly basis for a century and longer. These observations are directly compared to various CV evolution models. A complex set of agreements and disagreements is found.

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 absorption spectra, a mixture of both, asymmetric line profiles, very different slopes of the continuous flux distribution -- and one single system may exhibit all of these features at different times. Agreement and disagreement between computed and observed spectra should show whether or not the Roche model is applicable and where it probably will have to be modified and improved. Except for their outburst behavior and its immediate consequences, novae, dwarf novae, and nova-like stars cannot be physically distinguished from each other.

Dance of the Light Echoes

NASA Image and Video Library

2008-05-29

This composite image from NASA Spitzer Space Telescope shows the remnant of a star that exploded, called Cassiopeia A center and its surrounding light echoes -- dances of light through dusty clouds, created when stars blast apart.

High resolution observations of Cassiopeia A at meter wavelengths. [pulsar source in supernova remnant

NASA Technical Reports Server (NTRS)

Hutton, L. K.; Clark, T. A.; Erickson, W. C.; Resch, G. M.; Vandenberg, N. R.; Knowles, S. H.; Youmans, A. B.

1974-01-01

Very long baseline interferometric (VLBI) observations of the supernova remnant Cassiopeia A, at 74 MHz with a 12,000-wavelength baseline and at 111 MHz with a 18,500-wavelength baseline, are reported. The fringe amplitudes are strongly varying on a time scale of about 15 to 30 minutes. The location of the extra source must lie outside the supernova remnant shell possibly associated with a concentration of emission north of the shell, or lying outside the gap in the northeastern side of the shell. The flux and spectral index deduced for the compact source depend on the assumed size, with a range of 100 Jy to 500 Jy at 74 MHz. If the source is associated with the supernova explosion, it must have been traveling at least 5000 km s/2.

Variable Stars in the M31 Dwarf Spheroidal Companion Cassiopeia

NASA Astrophysics Data System (ADS)

Pritzl, Barton J.; Armandroff, T. E.; Jacoby, G. H.; Da Costa, G. S.

2007-12-01

Dwarf spheroidal galaxies show very diverse star formation histories. For the Galactic dwarf spheroidal galaxies, a correlation exists between Galactocentric distance and the prominence of intermediate-age ( 2 - 10 Gyr) populations. To test whether this correlation exists for the M31 dwarf spheroidal galaxies, we observed the Cassiopeia (And VII) dwarf galaxy, which is one of the most distant M31 dwarf spheroidal galaxies. We will present the results of a variable star search using HST/ACS data, along with a preliminary color-magnitude diagram. From the RR Lyrae stars we can obtain an independent distance and metallicity estimate for the dwarf galaxy. These results will be compared to those found for the other M31 dwarf spheroidal galaxies.This research is supported in part by NASA through grant number GO-11081.11 from the Space Telescope Science Institute.

Observations of Non Typical Masers at the RT-22 Radio Telescope in 2004-2013

NASA Astrophysics Data System (ADS)

Shulga, V. M.; Antyufeyev, O. V.; Zubrin, S. Y.; Myshenko, V. V.; Piddyachiy, V. I.; Korolev, A. M.; Patoka, O. M.

2017-06-01

Purpose: Some peculiarities of emission of Class I methanol masers on the 80-71A+ transition at 95 GHz in sources closely associated with protostar-forming regions and in supernova remnants are studied. Here belongs the investigation of SiO (J=2-1) maser variability in R Cassiopeiae, too. Design/methodology/approach: Search for Class I methanol masers is based on the idea of coincidence of regions of their emission with sources of OH masing transition in the bottom level of energy at frequency of 1720 MHz (2Π3/2 J=3/2 F=2-1). Findings: Two methanol masers on transition 80-71A+ (95 GHz) in the supernova remnants IC 443 and Kes 79 are detected. Variabilities of SiO maser emission on transition J=2-1 in R Cassiopeiae are shown for the first time. Conclusions: Variability of methanol and SiO masers is their general feature. On the example of three objects, the possibility of using the 1720 MHz OH maser as an indicator in the search for Class I methanol masers is shown. Especially it is important in the study of methanol maser emission in supernova remnants that has been proved to be true by detection of methanol masers on transition 80-71A+ (95 GHz) in IC 443 and Kes 79. Features of spectra variability of emission in R Cassiopeiae testify to formation and disappearance of SiO (J=2-1) masers.

NR TrA (Nova TrA 2008) monitoring in support of XMM observations

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2017-03-01

Dr. Fred Walter (Stony Brook University) has requested AAVSO observers' assistance in monitoring NR TrA (Nova TrA 2008) in support of upcoming XMM Newton observations. The XMM observations will take place 2017 March 13 06:21 through March 14 10:34 UT. Walter writes: "NR TrA (Nova TrA 2008) is a compact eclipsing system with a 5.5 hour period. It was a normal Fe II nova that, upon reaching quiescence, took on the appearance of a super-soft source in the optical high state, which suggests an extremely high mass accretion rate. The optical spectrum is dominated by hot permitted lines of O VI, N V, C IV, and He II. Some nova-like variables have similar spectra, though generally without the hot emission lines. Primary eclipse is broad - nearly 40% of the orbit - and deeper at shorter wavelengths, which suggests the eclipse of a hot accretion disk. Primary eclipse depth is about 1 mag at V. There appears to be a shallow secondary eclipse.The primary aim [of the XMM observations] is to detect and characterize the eclipse at X-ray and UV wavelengths. We will obtain low cadence BVRI/JHK observations with SMARTS/Andicam. We request AAVSO support to obtain continuous photometric time series simultaneous with the XMM observation. Any filters are acceptable, but standard Johnson B, V or Cousins R, I are preferred. Clear filters are acceptable. Time resolution better than 5 minutes and uncertainties (outside of eclipse) <0.02 mag are preferred. The best ephemeris I have is: minimum light at JD 55956.822 + 0.219109E. This is based on data from 2013-2015." Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

Regioisomer-specific electron affinities and electronic structures of C 70 para-adducts at polar and equatorial positions with (bromo)benzyl radicals: photoelectron spectroscopy and theoretical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, Gao-Lei; Li, Lei-Jiao; Li, Shu-Hui

Negative ion photoelectron spectroscopy shows interesting regioisomer-specific electron affinities (EAs) of 2,5– and 7,23– para-adducts of C70 [(ArCH2)2C70] (Ar = Ph, o-, m-, and p-BrC6H4). Their EA values are larger than that of C70 by 5-150 meV with the 2,5– polar adducts’ EAs being higher than their corresponding 7,23– equatorial counterparts, exhibiting appreciable EA tunable ranges and regioisomer specificity. Density functional theory (DFT) calculations reproduce both the experimental EA values and EA trends very well.

Epidemiologic studies on Theileria equi infections for grazing horses in Ili of Xinjiang province.

PubMed

Zhang, Yang; Chahan, Bayin; Liu, Shifang; Song, Ruiqi; Li, Yongchang; Huercha; Guo, Qingyong; Wu, Hui; Zhu, Yutao

2017-09-15

In order to found the epidemiological situation of T. equi in the horse herds in Ili Prefecture of Xinjiang Province, 723 blood samples collected from 4 counties and districts were test for T. equi through microscopic detection and Polymerase chain Reaction (PCR). In the result, we found that the 295 of 723 blood samples (40.8%) were positive for T. equi infection. The results showed that the choosed counties have a varying degrees infection. To our knowledge, this is the first time that we detected T. equi infection using the molecular techniques from Ili in Xinjiang Uygur Autonomous region. Copyright © 2017 Elsevier B.V. All rights reserved.

Nova Centauri 2013 = PNV J13544700-5909080

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2013-12-01

Announces the discovery of V1369 Cen = Nova Cen 2013 = PNV J13544700-5909080 by John Seach (Chatsworth Island, NSW, Australia) at unfiltered magnitude 5.5 on 2013 December 02.692 UT. Low-resolution spectra obtained by Locke on Dec. 03.3776 UT and by Kaufman on Dec. 03.621 UT show strong Ha and Hb emission lines, indicating the object is a nova. Announced on IAU CBAT Central Bureau Electronic Telegram 3732 (Daniel W. E. Green, ed.). Finder charts with sequences 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.

MULTIWAVELENGTH PHOTOMETRY AND HUBBLE SPACE TELESCOPE SPECTROSCOPY OF THE OLD NOVA V842 CENTAURUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sion, Edward M.; Szkody, Paula; Mukadam, Anjum

2013-08-01

We present ground-based optical and near infrared photometric observations and Hubble Space Telescope (HST) COS spectroscopic observations of the old nova V842 Cen (Nova Cen 1986). Analysis of the optical light curves reveals a peak at 56.5 {+-} 0.3 s with an amplitude of 8.9 {+-} 4.2 mma, which is consistent with the rotation of a magnetic white dwarf primary in V842 Cen that was detected earlier by Woudt et al., and led to its classification as an intermediate polar. However, our UV lightcurve created from the COS time-tag spectra does not show this periodicity. Our synthetic spectral analysis ofmore » an HST COS spectrum rules out a hot white dwarf photosphere as the source of the FUV flux. The best-fitting model to the COS spectrum is a full optically thick accretion disk with no magnetic truncation, a low disk inclination angle, low accretion rate and a distance less than half the published distance that was determined on the basis of interstellar sodium D line strengths. Truncated accretion disks with truncation radii of 3 R{sub wd} and 5 R{sub wd} yielded unsatisfactory agreement with the COS data. The accretion rate is unexpectedly low for a classical nova only 24 yr after the explosion when the accretion rate is expected to be high and the white dwarf should still be very hot, especially if irradiation of the donor star took place. Our low accretion rate is consistent with those derived from X-ray and ground-based optical data.« less

Lighting up a Dead Star Layers

NASA Image and Video Library

2006-10-26

This image from NASA Spitzer Space Telescope shows the scattered remains of an exploded star named Cassiopeia A. Spitzer infrared detectors picked through these remains and found that much of the star original layering had been preserved.

Echoes of a Stellar Ending

NASA Image and Video Library

2012-03-14

Listed as Cassiopeia A, this remnant of the supernova is one of the brightest radio sources in the known universe. More recently, NASA WISE telescope detected infrared echoes of the flash of light rippling outwards from the supernova.

Effects of common hemoglobin variants on HbA1c measurements in China: results for α- and β-globin variants measured by six methods.

PubMed

Xu, Anping; Chen, Weidong; Xia, Yong; Zhou, Yu; Ji, Ling

2018-04-07

HbA1c is a widely used biomarker for diabetes mellitus management. Here, we evaluated the accuracy of six methods for determining HbA1c values in Chinese patients with common α- and β-globin chains variants in China. Blood samples from normal subjects and individuals exhibiting hemoglobin variants were analyzed for HbA1c, using Sebia Capillarys 2 Flex Piercing (C2FP), Bio-Rad Variant II Turbo 2.0, Tosoh HLC-723 G8 (ver. 5.24), Arkray ADAMS A1c HA-8180V fast mode, Cobas c501 and Trinity Ultra2 systems. DNA sequencing revealed five common β-globin chain variants and three common α-globin chain variants. The most common variant was Hb E, followed by Hb New York, Hb J-Bangkok, Hb G-Coushatta, Hb Q-Thailand, Hb G-Honolulu, Hb Ube-2 and Hb G-Taipei. Variant II Turbo 2.0, Ultra2 and Cobas c501 showed good agreement with C2FP for most samples with variants. HLC-723 G8 yielded no HbA1c values for Hb J-Bangkok, Hb Q-Thailand and Hb G-Honolulu. Samples with Hb E, Hb G-Coushatta, Hb G-Taipei and Hb Ube-2 produced significant negative biases for HLC-723 G8. HA-8180V showed statistically significant differences for Hb E, Hb G-Coushatta, Hb G-Taipei, Hb Q-Thailand and Hb G-Honolulu. HA-8180V yielded no HbA1c values for Hb J-Bangkok. All methods showed good agreement for samples with Hb New York. Some common hemoglobin variants can interfere with HbA1c determination by the most popular methods in China.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Alexander; Ayres, Thomas R.; Neff, James E.

2015-02-01

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

McConnell AFB, Witchita, Kansas. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1981-12-14

96. 96. 97. 97.3 979; 97.8 97.9 97.9 97.9 97.9 97.9 97.9 97.9~~v 78q9o 5q90 7 90 8u 98.380 6� 98*7 98, �,7 98,7 S700 95:1 9b:’ 08’ 0 * 98o77 6...69o9 7301 70.2 70.2 70.3 7003 70.3 70.3 70o3 70.4 70o4 73.4 7o.4 : 8000 50 71, 71T6 71o 72 701 T71 -72 F2 7 o3 72.3 -.1 72,3 72 o 3 72.3 M7 2 ,3. S700 ...97.5 97.5 97o5 97o5 97,5 Roo 80. 95. 96. 97. 97s 97. 97. 98.1 98.1 98.1 98.1 98.1 98.1 98.1 98.1 Q81 S700 8 8 98 8 98. 98. 98. . 98. 9811117 17 17 .8

Spectral and photometric study of the symbiotic nova RS ophiuchus in quiet phase

NASA Astrophysics Data System (ADS)

Kondratyeva, L.; Rspaev, F.; Krugov, M.; Serebryanskiy, A.

2017-07-01

The results of spectral and photometric study of the recurrent Nova RS Ophiuchus are presented and discussed. Observations were carried out in 2009-2016. During these eight years the fluxes of HI and FeII emission lines have slightly decreased by a factor of 3 - 4. Hα and Hβ exhibit double-peaked profiles with a central absorption. The ratio of the blue and red peaks intensities(V/R) varies from 0.3 to 1.0 for Hβ and from 0.4 to 0.7 for Hα. Possible correlations between changes of the ratio and other spectral parameters were investigated. Dependence of V/R on the radial velocity of absorbtion component is found out.

Soul Nebula

NASA Image and Video Library

2010-04-05

This mosaic from NASA WISE Telescope is of the Soul Nebula. It is an open cluster of stars surrounded by a cloud of dust and gas located about 6,500 light-years from Earth in the constellation Cassiopeia, near the Heart Nebula.

Supernova Remnant in 3-D

NASA Image and Video Library

2009-01-06

For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several NASA telescopes.

Maffei 1 and 2

NASA Image and Video Library

2010-03-06

This mosaic of images from NASA WISE Telescope is in the constellation of Cassiopeia. This region contains a large star forming nebula within the Milky Way Galaxy, sometimes called the Heart Nebula, and is over 6 thousand light-years from Earth.

History of Chandra X-Ray Observatory

NASA Image and Video Library

1999-08-01

This is an extraordinary first image from the Chandra X-Ray Observatory (CXO), the supernova remnant Cassiopeia A, tracing the aftermath of a gigantic stellar explosion in such sturning detail that scientists can see evidence of what may be a neutron star or black hole near the center. The red, green, and blue regions in this image of the supernova remnant Cassiopeia A show where the intensity of low, medium, and high energy X-rays, respectively, is greatest. The red material on the left outer edge is enriched in iron, whereas the bright greenish white region on the low left is enriched in silicon and sulfur. In the blue region on the right edge, low and medium energy X-rays have been filtered out by a cloud of dust and gas in the remnant . The image was made with the CXO's Advanced Charged-Coupled Device (CCD) Imaging Spectrometer (ACIS). Photo credit: NASA/CXC/SAO/Rutgers/J.Hughes

Constraining Calcium Production in Novae

NASA Astrophysics Data System (ADS)

Tiwari, Pranjal; C. Fry, C. Wrede Team; A. Chen, J. Liang Collaboration; S. Bishop, T. Faestermann, D. Seiler Collaboration; R. Hertenberger, H. Wirth Collaboration

2017-09-01

Calcium is an element that can be produced by thermonuclear reactions in the hottest classical novae. There are discrepancies between the abundance of Calcium observed in novae and expectations based on astrophysical models. Unbound states 1 MeV above the proton threshold affect the production of Calcium in nova models because they act as resonances in the 38 K(p , γ) 39 Ca reaction present. This work describes an experiment to measure the energies of the excited states of 39 Ca . We will bombard a thin target of 40 Ca with a beam of 22 MeV deuterons, resulting in tritons and 39Ca. We will use a Q3D magnetic spectrograph from the MLL in Garching, Germany to momenta analyze the tritons to observe the excitation energies of the resulting 39 Ca states. Simulations have been run to determine the optimal spectrograph settings. We decided to use a chemically stable target composed of CaF2 , doing so resulted in an extra contaminant, Fluorine, which is dealt with by measuring the background from a LiF target. These simulations have led to settings and targets that will result in the observation of the 39 Ca states of interest with minimal interference from contaminants. Preliminary results from this experiment will be presented. National Sciences and Engineering Research Council of Canada and U.S. National Science Foundation.

Nova in Ophiuchus

NASA Astrophysics Data System (ADS)

Templeton, Matthew R.

2009-08-01

Nova Ophiuchi 2009 was discovered by Koichi Itagaki, Teppo-Cho, Yamagata, Japan, at unfiltered CCD magnitude 10.1 on August 16.515 UT, and confirmed by him on Aug. 16.526. After posting to the CBET Unconfirmed Observations page, the object was confirmed independently by several observers. The discovery and confirmatory information were intially reported in CBET 1910, CBET 1911, and AAVSO Special Notice #166. The nova, located in a very crowded field within the Milky Way, is reported by T. Kato (vsnet-alert 11399) to have a large B-V (+1.6), indicating it is highly reddened. N Oph 2009 has been assigned the identifiers VSX J173819.7-264413 and the AUID 000-BJP-605. Please submit observations to the AAVSO International Database using the name N OPH 2009.

Toward an experimentally determined {sup 26}Al{sup m}(p,{gamma}){sup 27}Si reaction rate in ONe novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deibel, C. M.; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439; Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824

2009-09-15

Strong evidence of the nucleosynthesis of Galactic {sup 26}Al has been found through measurements involving excesses in {sup 26}Mg from the decay of {sup 26}Al in meteoritic inclusions and the 1.809-MeV {gamma}-ray line detected by satellites such as CGRO and INTEGRAL. Several sites for the production of {sup 26}Al have been suggested, including ONe novae. Destruction of {sup 26}Al in ONe novae is possible via the reactions {sup 26}Al{sup g}(p,{gamma}){sup 27}Si and {sup 26}Al{sup m}(p,{gamma}){sup 27}Si. In the present work, resonance parameters for the {sup 26}Al{sup m}(p,{gamma}){sup 27}Si reaction have been determined via studies of the {sup 27}Al({sup 3}He,t){sup 27}Si*(p){supmore » 26}Al{sup m} and {sup 28}Si({sup 3}He,{alpha}){sup 27}Si*(p){sup 26}Al{sup m} reactions. Several new {sup 26}Al{sup m}+p resonances have been discovered within 1 MeV above the proton threshold of 7.691 MeV. Excitation energies and proton-branching ratios for those and previously known states are reported.« less

The Early Spectral Evolution of the Classical Nova ASASSN-15th in M33

NASA Astrophysics Data System (ADS)

Wagner, R. Mark; Neric, Marko; Darnley, Matt J.; Williams, Steven; Starrfield, Sumner; Woodward, Charles E.; Prieto, Jose Luis

2016-06-01

During the course of the All Sky Automated Survey for SuperNovae (ASAS-SN) a new transient source designated ASASSN-15th was identified on images of the nearby galaxy M33 obtained with the 14 cm Brutus telescope in Haleakala, Hawaii on 2015 Dec 1.4 UT at V ~ 16.5 mag. Given the location of the transient in M33 and its apparent V magnitude at discovery, the implied absolute visual magnitude was about -8.5 mag suggesting that the transient was a new classical nova outburst in M33. Optical spectroscopy obtained by us on 2015 Dec 2.3 showed broad emission lines of Balmer, Fe II, and Na I D with P Cygni-type line profiles superposed on a blue continuum. The spectrum was consistent with a Fe II-type classical nova in M33 discovered early in the outburst. Subsequent spectra obtained by us on 2015 Dec 10.9 UT showed significant evolution since our first spectrum in that the deep P Cygni-type line profiles seen earlier were now extremely shallow or had almost completely disappeared with the emission component growing in strength. Additional emission lines from O I, Si II, and possibly He I were also present. We obtained optical spectroscopy of ASASSN-15th on 17 epochs between 2015 Dec 1 and 2016 Feb 11 UT with the 2.4 m Hiltner telescope (+OSMOS) of the MDM Observatory, the 2 m fully robotic Liverpool Telescope (+SPRAT), and the 2 x 8.4 m Large Binocular Telescope (+MODS). We will present our spectroscopy and discuss the early evolution of ASASSN-15th in the context of Galactic Fe II-class novae.

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.

Constraining the astrophysical 23Mg(p, γ)24Al reaction rate using the 23Na(d,p)24Na reaction

NASA Astrophysics Data System (ADS)

Bennett, E. A.; Catford, W. N.; Christian, G.; Dede, S.; Hallam, S.; Lotay, G.; Ota, S.; Saastamoinen, A.; Wilkinson, R.

2017-09-01

The 23Mg(p, γ)24Al reaction provides an escape from the Ne-Na cycle in classical novae and is therefore important in understanding nova nucleosynthesis in the A > 20 mass range. Although several resonances may contribute to the overall rate at novae temperatures, the resonance at 475 keV is thought to be dominant. The strength of this resonance has been directly measured using a radioactive 23Mg beam impinging on a windowless H2 gas target; however, recent high-precision 24Al mass measurements have called this result into question. Here we make an indirect measurement using the 23Na(d,p)24Na reaction in inverse kinematics to study the mirror state of the 475 keV resonance in 24Na. The experiment, performed at the Texas A&M Cyclotron Institute, utilized the TIARA silicon array, four HPGe detectors, and the MDM spectrometer to measure the excited states of the 24Na nucleus. Preliminary results from the experiment will be presented along with progress from the ongoing analysis.

Once an Onion, Always an Onion Artist Concept

NASA Image and Video Library

2006-10-26

This artist concept shows that NASA Spitzer Space Telescope found evidence that this star, the remains of which are named Cassiopeia A, exploded with some degree of order, preserving chunks of its onion-like layers as it blasted apart.

Sizzling Remains of a Dead Star

NASA Image and Video Library

2013-01-07

This new view of the historical supernova remnant Cassiopeia A, located 11,000 light-years away, was taken by NASA Nuclear Spectroscopic Telescope Array, or NuSTAR. While the star is long dead, its remains are still bursting with action.

Photometric Investigation of Novae T Pyx, BT Mon and V574 Pup at Quiescence by using the 2.4-m Thai National Telescope

NASA Astrophysics Data System (ADS)

Thipboon, Ritthichai; Kaewrakmuk, Metichai; Surina, Farung; Sanguansak, Nuanwan

2017-09-01

Recurrent novae (RNe) are novae with multiple recorded outbursts powered by a thermonuclear runaway. The outburst occurs on the surface of the white dwarf which accompanies with a late type main-sequence or giant secondary star transferring material onto the white dwarf primary star. They resemble classical novae (CNe) outbursts but only RNe has more than one recorded outbursts. RNe play an important role as one of the suspected progenitor systems of Type Ia supernovae (SNe) which are used as primary distance indicators in cosmology. Thus, it is important to investigate the outburst type of CNe and RNe and finally ascertain the population of objects that might ultimately be candidates for Type Ia SNe explosions. The proposal that RNe occupy a region separated from CNe in an outburst amplitude versus speed class diagram was adopted. Since the low amplitude results from the existence of an evolved secondary and/or high mass transfer rate in the quiescent system, RNe candidates should accordingly have low amplitude. We selected 3 preliminary targets including T Pyx, BT Mon and V574 Pup. Their amplitudes are not that low but the lowest amplitude that can be observed with Thai National Telescope (TNT). We obtained their magnitudes at quiescence using ULTRASPEC camera on the 2.4-m TNT. The positions of three targets on optical and near-infrared color-magnitude diagrams suggest that all three should have main-sequence secondary stars. This is true for T Pyx, whose secondary star has been confirmed its spectroscopy to be a main-sequence star, but not yet confirmed for BT Mon and V574 Pup.

Nova Scorpii 2011 = PNV J16551100-3838120

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2011-06-01

Announces the discovery of Nova Scorpii 2011 = PNV J16551100-3838120 by John Seach (Chatsworth Island, NSW, Australia) on 2011 June 1.40 UT at magnitude 9.5 (DSLR + orange filter). Spectra by Bernard Heathcote (South Yarra, Vic, Australia) on Jun 2.4896 UT, A. Arai, T. Kajikawa, and M. Nagashima (Kyoto Sangyo University, Japan) on 2011 June 2.68 UT, and Masayuki Yamanaka and Ryosuke Itoh (Hiroshima University, Japan) on Jun 2 UT indicate a highly-reddened classical nova. Initially reported to the AAVSO by Seach and announced in AAVSO Special Notice #240 (Arne Henden) and IAU CBET 2735 (Daniel W. E. Green, ed.). The object was designated PNV J18102135-2305306 when posted on the Central Bureau's Transient Objects Confirmation Page (TOCP) webpage. 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, observations, and links to images. [Nova Sco 2011 subsequently assigned the name V1312 Sco

Hubble Sees a Stellar "Sneezing Fit"

NASA Image and Video Library

2017-12-08

Look at the bright star in the middle of this image. It appears as if it just sneezed. This sight will only last for a few thousand years — a blink of an eye in the young star's life. If you could carry on watching for a few years you would realize it's not just one sneeze, but a sneezing fit. This young star is firing off rapid releases of super-hot, super-fast gas, like multiple sneezes, before it finally exhausts itself. These bursts of gas have shaped the turbulent surroundings, creating structures known as Herbig-Haro objects. These objects are formed from the star's energetic "sneezes." Launched due to magnetic fields around the forming star, these energetic releases can contain as much mass as our home planet, and cannon into nearby clouds of gas at hundreds of kilometers/miles per second. Shock waves form, such as the U-shape below this star. Unlike most other astronomical phenomena, as the waves crash outwards, they can be seen moving across human timescales of years. Soon, this star will stop sneezing, and mature to become a star like our sun. This region is actually home to several interesting objects. The star at the center of the frame is a variable star named V633 Cassiopeiae, with Herbig-Haro objects HH 161 and HH 164 forming parts of the horseshoe-shaped loop emanating from it. The slightly shrouded star just to the left is known as V376 Cassiopeiae, another variable star that has succumbed to its neighbor's infectious sneezing fits; this star is also sneezing, creating yet another Herbig-Haro object — HH 162. Both stars are very young and are still surrounded by dusty material left over from their formation, which spans the gap between the two. Credit: ESA/Hubble & NASA, Acknowledgement: Gilles Chapdelaine NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Biologic properties of a CH2 domain-deleted recombinant immunoglobulin.

PubMed

Slavin-Chiorini, D C; Horan Hand, P H; Kashmiri, S V; Calvo, B; Zaremba, S; Schlom, J

1993-01-02

Monoclonal antibody (MAb) B72.3 reacts with TAG-72, a high-molecular-weight mucin expressed on several types of human carcinoma, and is currently being used in clinical trials for the diagnosis and therapy of human carcinoma. An expression construct containing cDNA encoding an immunoglobulin (Ig) heavy chain, with the variable region of murine MAb B72.3 and a human Ig constant region with a deletion of the CH2 domain, was generated. Immunoglobulin from the transfectoma with the highest expression of the TAG-72 immunoreactive antibody was designated MAb chimeric (c) B72.3 delta CH2. The pharmacokinetics of serum clearance of iodine-labeled MAbs cB72.3 delta CH2 and the intact cB72.3 were compared in athymic mice. By 24 hr, less than 1% of the cB72.3 delta CH2 was left in the plasma, while 36% of the cB72.3 still remained. The T1/2 alpha values of the cB72.3 delta CH2 and cB72.3 MAbs were 1.7 and 2.4 hr, respectively. The T1/2 beta values were 7.8 hr for the domain-deleted cMAb and 48.9 hr for cB72.3. Biodistribution studies in athymic mice bearing LS-174T xenografts showed a reduction in the percentage of injected dose per gram in tumor with 131I-cB72.3 delta CH2; however, the 131I-cB72.3 delta CH2 both localized to tumors faster and cleared from the blood faster than the 125I-cB72.3 MAb. Only trace amounts of the 131I-cB72.3 delta CH2 were detected in normal tissues, including kidney. The faster clearance rate, more rapid tumor targeting and lack of metabolic uptake in normal tissues demonstrated with the iodine-labeled CH2 domain-deleted cMAb may be an advantage for certain clinical protocols.

BSN723T Prevents Atherosclerosis and Weight Gain in ApoE Knockout Mice Fed a Western Diet.

PubMed

Williams, Jarrod; Ensor, Charles; Gardner, Scott; Smith, Rebecca; Lodder, Robert

This study tests the hypothesis that BSN723T can prevent the development of hyperlipidemia and atherosclerosis in ApoE -/- knockout mice fed a Western (high fat, high cholesterol, and high sucrose) diet. BSN723T is a combination drug therapy consisting of D-tagatose and dihydromyricetin (BSN723). D-tagatose has an antihyperglycemic effect in animal and human studies and shows promise as a treatment for type 2 diabetes and obesity. Many claims regarding BSN723's pharmacological activities have been made including anti-cancer, anti-diabetic, anti-hypertensive, anti-inflammatory, and anti-atherosclerotic effects. To our knowledge this is the first study that combines D-tagatose and BSN723 for the treatment of hyperlipidemia and the prevention of atherosclerosis. ApoE-deficient mice were randomized into five groups with equivalent mean body weights. The mice were given the following diets for 8 weeks: Group 1 - Standard diet; Group 2 - Western diet; Group 3 - Western diet formulated with D-tagatose; Group 4 - Western diet formulated with BSN723; Group 5 - Western diet formulated with BSN723T. Mice were measured for weight gain, tissue and organ weights, total serum cholesterol and triglycerides and formation of atherosclerosis. The addition of D-tagatose, either alone or in combination with BSN723, prevented the increase in adipose tissue and weight gain brought on by the Western diet. Both D-tagatose and BSN723 alone reduced total cholesterol and the formation of atherosclerosis in the aorta compared to mice on the Western diet. Addition of BSN723 to D-tagatose (BSN723T) did not increase efficacy in prevention of increases in cholesterol or atherosclerosis compared to D-tagatose alone. Addition of either D-tagatose or BSN723 alone to a Western diet prevented weight gain, increases in total serum cholesterol and triglycerides, and the formation of atherosclerosis. However, there was no additive or synergistic effect on the measured parameters with the combination BSN723T treatment.

Tooling for War: Military Transformation in the Industrial Age

DTIC Science & Technology

1994-09-01

Ivan M. Aviation versus Submarines. Wright-Patterson AFB: Foreign Technology Division, 1971. V 214 .S71; Report Lit. AD 723 558. United States. Cong...Brown, Neville. New Strateav Through Space. Leicester, England; New York: Leicester UP, 1990. UGK 1012 .B879 1990. Canan , James W. War in Space. New

Improving the {sup 33}S(p,{gamma}){sup 34}Cl Reaction Rate for Models of Classical Nova Explosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parikh, A.; Faestermann, Th.; Kruecken, R.

2011-10-28

Reduced uncertainty in the thermonuclear rate of the {sup 33}S(p,{gamma}){sup 34}Cl reaction would help to improve our understanding of nucleosynthesis in classical nova explosions. At present, models are generally in concordance with observations that nuclei up to roughly the calcium region may be produced in these explosive phenomena; better knowledge of this rate would help with the quantitative interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint. As well, models find that the ejecta of nova explosions on massive oxygen-neon white dwarfs may contain as much as 150 times themore » solar abundance of {sup 33}S. This characteristic isotopic signature of a nova explosion could possibly be observed through the analysis of microscopic grains formed in the environment surrounding a nova and later embedded within primitive meteorites. An improved {sup 33}S(p,{gamma}){sup 34}Cl rate (the principal destruction mechanism for {sup 33}S in novae) would help to ensure a robust model prediction for the amount of {sup 33}S that may be produced. Finally, constraining this rate could confirm or rule out the decay of an isomeric state of {sup 34}Cl(E{sub x} = 146 keV, t{sub 1/2} = 32 m) as a source for observable gamma-rays from novae. We have performed several complementary experiments dedicated to improving our knowledge of the {sup 33}S(p,{gamma}){sup 34}Cl rate, using both indirect methods (measurement of the {sup 34}S({sup 3}He,t){sup 34}Cl and {sup 33}S({sup 3}He,d){sup 34}Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF). Our results will be used with nova models to facilitate comparisons of model predictions with present and future nova observables.« less

Dissecting the Wake of a Supernova Explosion

NASA Image and Video Library

2007-12-20

The elements and molecules that flew out of the Cassiopeia A star when it exploded about 300 years ago can be seen clearly for the first time in this plot of data, called a spectrum, taken by NASA Spitzer Space Telescope.

Optical Studies of 20 Longer-Period Cataclysmic Binaries

NASA Astrophysics Data System (ADS)

Thorstensen, John R.; Peters, Christopher S.; Skinner, Julie N.

2010-11-01

We obtained time-series radial-velocity spectroscopy of 20 cataclysmic variable stars, with the aim of determining orbital periods Porb. All of the stars reported here prove to have Porb > 3.5 h. For 16 of the stars, these are the first available period determinations, and for the remaining four (V709 Cas, AF Cam, V1062 Tau, and RX J2133 + 51), we use new observations to improve the accuracy of previously published periods. Most of the targets are dwarf novae, without notable idiosyncrasies. Of the remainder, three (V709 Cas, V1062 Tau, and RX J2133 + 51) are intermediate polars (DQ Her stars); one (IPHAS 0345) is a secondary-dominated system without known outbursts, similar to LY UMa; one (V1059 Sgr) is an old nova; and two others (V478 Her and V1082 Sgr) are long-period novalike variables. The stars with new periods are IPHAS 0345 (0.314 days) V344 Ori (0.234 days) VZ Sex (0.149 days) NSVS 1057 + 09 (0.376 days) V478 Her (0.629 days) V1059 Sgr (0.286 days) V1082 Sgr (0.868 days) FO Aql (0.217 days) V587 Lyr (0.275 days) V792 Cyg (0.297 days) V795 Cyg (0.181 days) V811 Cyg (0.157 days) V542 Cyg (0.182 days) PQ Aql (0.247 days) V516 Cyg (0.171 days) and VZ Aqr (0.161 days). Noteworthy results on individual stars are as follows. We see no indication of the underlying white dwarf star in V709 Cas, as has been previously claimed; based on the nondetection of the secondary star, we argue that the system is farther away that had been thought and the white dwarf contribution is probably negligible. V478 Her had been classified as an SU UMa-type dwarf nova, but this is incompatible with the long orbital period we find. We report the first secondary-star velocity curve for V1062 Tau. In V542 Cyg, we find a late-type contribution that remains stationary in radial velocity, yet the system is unresolved in a direct image, suggesting that it is a hierarchical triple system. Based on observations obtained at the MDM Observatory, operated by Dartmouth College, Columbia University, Ohio State University, Ohio University, and the University of Michigan.

Cosmic muon induced EM showers in NO$$\

DOE PAGES

Yadav, Nitin; Duyang, Hongyue; Shanahan, Peter; ...

2016-11-15

Here, the NuMI Off-Axis v e Appearance (NOvA) experiment is a ne appearance neutrino oscillation experiment at Fermilab. It identifies the ne signal from the electromagnetic (EM) showers induced by the electrons in the final state of neutrino interactions. Cosmic muon induced EM showers, dominated by bremsstrahlung, are abundant in NOvA far detector. We use the Cosmic Muon- Removal technique to get pure EM shower sample from bremsstrahlung muons in data. We also use Cosmic muon decay in flight EM showers which are highly pure EM showers.The large Cosmic-EM sample can be used, as data driven method, to characterize themore » EM shower signature and provides valuable checks of the simulation, reconstruction, particle identification algorithm, and calibration across the NOvA detector.« less

Cosmic muon induced EM showers in NO$$\

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Nitin; Duyang, Hongyue; Shanahan, Peter

Here, the NuMI Off-Axis v e Appearance (NOvA) experiment is a ne appearance neutrino oscillation experiment at Fermilab. It identifies the ne signal from the electromagnetic (EM) showers induced by the electrons in the final state of neutrino interactions. Cosmic muon induced EM showers, dominated by bremsstrahlung, are abundant in NOvA far detector. We use the Cosmic Muon- Removal technique to get pure EM shower sample from bremsstrahlung muons in data. We also use Cosmic muon decay in flight EM showers which are highly pure EM showers.The large Cosmic-EM sample can be used, as data driven method, to characterize themore » EM shower signature and provides valuable checks of the simulation, reconstruction, particle identification algorithm, and calibration across the NOvA detector.« less

28 CFR 42.723 - Compliance information.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 28 Judicial Administration 1 2014-07-01 2014-07-01 false Compliance information. 42.723 Section 42.723 Judicial Administration DEPARTMENT OF JUSTICE NONDISCRIMINATION; EQUAL EMPLOYMENT OPPORTUNITY...; Implementation of the Age Discrimination Act of 1975 Duties of Recipients § 42.723 Compliance information. (a...

5 CFR 723.160 - Communications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Communications. 723.160 Section 723.160... PERSONNEL MANAGEMENT § 723.160 Communications. (a) The agency shall take appropriate steps to ensure effective communication with applicants, participants, personnel of other Federal entities, and members of...

5 CFR 723.160 - Communications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Communications. 723.160 Section 723.160... PERSONNEL MANAGEMENT § 723.160 Communications. (a) The agency shall take appropriate steps to ensure effective communication with applicants, participants, personnel of other Federal entities, and members of...

Computer Simulation of Magnetic Nova Shell Expantion

NASA Astrophysics Data System (ADS)

Dudnikova, Galina; Nikitin, Sergei; Snytnikov, Valeri; Vshivkov, Vitali

2000-10-01

An asymmetrical character of the shell expantion observed at many Nova may be associated with infuence of an inherent star magnetic field. Magneto-dipole energy of a Nova is much less than a kinetic energy of an exploding envelope. By this reason the conventional hydrodynamic models of point-like explosion with a spherical outward-directed shock wave do not consider effect of star magnetic field on the plasma movement. We used the numerical model based on the system of equations of the hybrid type( MHD approximation for electrons and Vlasov kinetic equations for ions). PIC-method for solving Vlasov equations was used. It gives an opportunaty to consider a complicated multi-flow motion of particles in plasma at super-Alfven velocity. At the beginning there is an immobile (cold) background plasma of a homogeneous concentration in a cylindrical region with a dipole magnetic field. Into the central spherical region of radius R, where the magnetic field remains uniform and constant , the external plasma does not penetrate with elastic reflections of ions at the spherical core surface. This boundary is spaced at r<

BSN723T Prevents Atherosclerosis and Weight Gain in ApoE Knockout Mice Fed a Western Diet

PubMed Central

Williams, Jarrod; Ensor, Charles; Gardner, Scott; Smith, Rebecca; Lodder, Robert

2016-01-01

Objective This study tests the hypothesis that BSN723T can prevent the development of hyperlipidemia and atherosclerosis in ApoE-/- knockout mice fed a Western (high fat, high cholesterol, and high sucrose) diet. BSN723T is a combination drug therapy consisting of D-tagatose and dihydromyricetin (BSN723). Background D-tagatose has an antihyperglycemic effect in animal and human studies and shows promise as a treatment for type 2 diabetes and obesity. Many claims regarding BSN723's pharmacological activities have been made including anti-cancer, anti-diabetic, anti-hypertensive, anti-inflammatory, and anti-atherosclerotic effects. To our knowledge this is the first study that combines D-tagatose and BSN723 for the treatment of hyperlipidemia and the prevention of atherosclerosis. Methods ApoE-deficient mice were randomized into five groups with equivalent mean body weights. The mice were given the following diets for 8 weeks: Group 1 - Standard diet; Group 2 - Western diet; Group 3 - Western diet formulated with D-tagatose; Group 4 - Western diet formulated with BSN723; Group 5 - Western diet formulated with BSN723T. Mice were measured for weight gain, tissue and organ weights, total serum cholesterol and triglycerides and formation of atherosclerosis. Results The addition of D-tagatose, either alone or in combination with BSN723, prevented the increase in adipose tissue and weight gain brought on by the Western diet. Both D-tagatose and BSN723 alone reduced total cholesterol and the formation of atherosclerosis in the aorta compared to mice on the Western diet. Addition of BSN723 to D-tagatose (BSN723T) did not increase efficacy in prevention of increases in cholesterol or atherosclerosis compared to D-tagatose alone. Conclusion Addition of either D-tagatose or BSN723 alone to a Western diet prevented weight gain, increases in total serum cholesterol and triglycerides, and the formation of atherosclerosis. However, there was no additive or synergistic effect on the measured parameters with the combination BSN723T treatment. PMID:27683620

5 CFR 723.150 - Program accessibility: Existing facilities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... facilities. 723.150 Section 723.150 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL... ACTIVITIES CONDUCTED BY THE OFFICE OF PERSONNEL MANAGEMENT § 723.150 Program accessibility: Existing... would result in a fundamental alteration in the nature of a program or activity or in undue financial...

5 CFR 723.140 - Employment.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Employment. 723.140 Section 723.140... PERSONNEL MANAGEMENT § 723.140 Employment. No qualified individual with handicaps shall, on the basis of handicap, be subject to discrimination in employment under any program or activity conducted by the agency...

The inter-outburst behavior of cataclysmic variables

NASA Technical Reports Server (NTRS)

Szkody, Paula; Mattei, Janet A.; Waagen, Elizabeth O.; Stablein, Clay

1990-01-01

Existing International Ultraviolet Explorer (IUE) and American Association of Variable Star Observers (AAVSO) archive data was used to accomplish a large scale study of what happens to the ultraviolet flux of accretion disk systems during the quiescent intervals between outbursts and how it relates to the preceding outburst characteristics of amplitude and width. The data sample involved multiple IUE observations for 16 dwarf novae and 8 novae along with existing optical coverage. Results indicate that most systems show correlated ultraviolet (UV) flux behavior with interoutburst phase, with 60 percent of the dwarf novae and 50 percent of the novae having decreasing flux trends while 33 percent of the dwarf novae and 38 percent of the novae show rising UV flux during the quiescent interval. All of the dwarf novae with decreasing UV fluxes at 1475A have orbital periods longer than 4.4 hours, while all (except BV Cen) with flat or rising fluxes at 1475A have orbital periods less than two hours. There are not widespread correlations of the UV fluxes with the amplitude of the preceding outburst and no correlations with the width of the outburst. From a small sample (7) that have relatively large quiescent V magnitude changes between the IUE observations, most show a strong correlation between the UV and optical continuum. Interpretation of the results is complicated by not being able to determine how much the white dwarf contributes to the ultraviolet flux. However, it is now evident that noticeable changes are occurring in the hot zones in accreting systems long after the outburst, and not only for systems that are dominated by the white dwarf. Whether these differences are due to different outburst mechanisms or to changes on white dwarfs which provide varying contributions to the UV flux remains to be determined.

ASASSN-16eg: New candidate for a long-period WZ Sge-type dwarf nova

NASA Astrophysics Data System (ADS)

Wakamatsu, Yasuyuki; Isogai, Keisuke; Kimura, Mariko; Kato, Taichi; Vanmunster, Tonny; Stone, Geoff; Tordai, Tamás; Richmond, Michael; Miller, Ian; Oksanen, Arto; Itoh, Hiroshi; Akazawa, Hidehiko; Kiyota, Seiichiro; de Miguel, Enrique; Pavlenko, Elena P.; Antonyuk, Kirill A.; Antonyuk, Oksana I.; Neustroev, Vitaly V.; Sjoberg, George; Dubovsky, Pavol A.; Pickard, Roger D.; Nogami, Daisaku

2017-12-01

We report on our photometric observations of the 2016 superoutburst of ASASSN-16eg. This object showed a WZ Sge-type superoutburst with prominent early superhumps with a period of 0.075478(8) d and a post-superoutburst rebrightening. During the superoutburst plateau, it showed ordinary superhumps with a period of 0.077880(3) d and a period derivative of 10.6(1.1) × 10-5 in stage B. The orbital period (Porb), which is almost identical with the period of the early superhumps, is exceptionally long for a WZ Sge-type dwarf nova. The mass ratio (q = M2/M1) estimated from the period of developing (stage A) superhumps is 0.166(2), which is also too large for a WZ Sge-type dwarf nova. This suggests that the 2 : 1 resonance can be reached in such high-q systems, contrary to our expectation. Such conditions are considered to be achieved if the mass-transfer rate is much lower than those in typical SU UMa-type dwarf novae that have comparable orbital periods to ASASSN-16eg, and a resultant accumulation of a large amount of matter on the disk is realized at the onset of an outburst. We examined other candidates for long-period WZ Sge-type dwarf novae for their supercycles, which are considered to reflect the mass-transfer rate, and found that V1251 Cyg and RZ Leo have longer supercycles than those of other WZ Sge-type dwarf novae. This result indicates that these long-period objects including ASASSN-16eg have a low mass-transfer rate in comparison to other WZ Sge-type dwarf novae.

USSR and Eastern Europe Scientific Abstracts, Engineering and Equipment, Number 31

DTIC Science & Technology

1977-04-18

average coefficient of air absorption is computed by the method of approximate replacement of the real spectrum by the graduated one. The entire range...end of transition area with an accuracy of 15%. Figures 5; References 7. USSR UDC 541.24:532.5 PARAMETRIC METHOD OF CALCULATION OF THERMODYNAMIC...12, 1976 Abstract No 12B723 by V. A. Polyanskiy] GLEBOV, G. A., and KOSHKIN, V. K. [Text] A method is presented for calculation of thermodynamic

Bright gamma-ray emission from TCP J04432130+4721280 (V392 Per) detected by Fermi-LAT

NASA Astrophysics Data System (ADS)

Li, Kwan-Lok; Chomiuk, Laura; Strader, Jay

2018-05-01

We report the Fermi-LAT detection of the optical transient TCP J04432130+4721280 (V392 Per), which was discovered by Yuji Nakamura on 2018-04-29.4740 (CBET #4515) and later identified as a Galactic nova by Wagner et al. (ATel #11588).

Energy contribution of NOVA food groups and sociodemographic determinants of ultra-processed food consumption in the Mexican population.

PubMed

Marrón-Ponce, Joaquín A; Sánchez-Pimienta, Tania G; Louzada, Maria Laura da Costa; Batis, Carolina

2018-01-01

To identify the energy contributions of NOVA food groups in the Mexican diet and the associations between individual sociodemographic characteristics and the energy contribution of ultra-processed foods (UPF). We classified foods and beverages reported in a 24 h recall according to the NOVA food framework into: (i) unprocessed or minimally processed foods; (ii) processed culinary ingredients; (iii) processed foods; and (iv) UPF. We estimated the energy contribution of each food group and ran a multiple linear regression to identify the associations between sociodemographic characteristics and UPF energy contribution. Mexican National Health and Nutrition Survey 2012. Individuals ≥1 years old (n 10 087). Unprocessed or minimally processed foods had the highest dietary energy contribution (54·0 % of energy), followed by UPF (29·8 %), processed culinary ingredients (10·2 %) and processed foods (6·0 %). The energy contribution of UPF was higher in: pre-school-aged children v. other age groups (3·8 to 12·5 percentage points difference (pp)); urban areas v. rural (5·6 pp); the Central and North regions v. the South (2·7 and 8·4 pp, respectively); medium and high socio-economic status v. low (4·5 pp, in both); and with higher head of household educational level v. without education (3·4 to 7·8 pp). In 2012, about 30 % of energy in the Mexican diet came from UPF. Our results showed that younger ages, urbanization, living in the North region, high socio-economic status and high head of household educational level are sociodemographic factors related to higher consumption of UPF in Mexico.

27 CFR 19.723 - Maintenance and preservation of records.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Maintenance and preservation of records. 19.723 Section 19.723 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX... General § 19.723 Maintenance and preservation of records. (a) Place of maintenance. Records required by...

46 CFR 169.723 - Safety belts.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Safety belts. 169.723 Section 169.723 Shipping COAST... Control, Miscellaneous Systems, and Equipment § 169.723 Safety belts. Each vessel must carry a harness type safety belt conforming to Offshore Racing Council (ORC) standards for each person on watch or...

40 CFR 723.250 - Polymers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymers. 723.250 Section 723.250... PREMANUFACTURE NOTIFICATION EXEMPTIONS Specific Exemptions § 723.250 Polymers. (a) Purpose and scope. (1) This...) of the Toxic Substances Control Act (15 U.S.C. 2604(a)(1)(A)) for the manufacture of certain polymers...

40 CFR 723.250 - Polymers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymers. 723.250 Section 723.250... PREMANUFACTURE NOTIFICATION EXEMPTIONS Specific Exemptions § 723.250 Polymers. (a) Purpose and scope. (1) This...) of the Toxic Substances Control Act (15 U.S.C. 2604(a)(1)(A)) for the manufacture of certain polymers...

40 CFR 723.250 - Polymers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymers. 723.250 Section 723.250... PREMANUFACTURE NOTIFICATION EXEMPTIONS Specific Exemptions § 723.250 Polymers. (a) Purpose and scope. (1) This...) of the Toxic Substances Control Act (15 U.S.C. 2604(a)(1)(A)) for the manufacture of certain polymers...

40 CFR 723.250 - Polymers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymers. 723.250 Section 723.250... PREMANUFACTURE NOTIFICATION EXEMPTIONS Specific Exemptions § 723.250 Polymers. (a) Purpose and scope. (1) This...) of the Toxic Substances Control Act (15 U.S.C. 2604(a)(1)(A)) for the manufacture of certain polymers...

36 CFR 7.23 - Badlands National Park.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Badlands National Park. 7.23 Section 7.23 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.23 Badlands National Park. (a) Commercial vehicles. (1...

36 CFR 7.23 - Badlands National Park.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Badlands National Park. 7.23 Section 7.23 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.23 Badlands National Park. (a) Commercial vehicles. (1...

36 CFR 7.23 - Badlands National Park.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Badlands National Park. 7.23 Section 7.23 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.23 Badlands National Park. (a) Commercial vehicles. (1...

36 CFR 7.23 - Badlands National Park.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Badlands National Park. 7.23 Section 7.23 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.23 Badlands National Park. (a) Commercial vehicles. (1...

36 CFR 7.23 - Badlands National Park.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Badlands National Park. 7.23 Section 7.23 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.23 Badlands National Park. (a) Commercial vehicles. (1...

46 CFR 169.723 - Safety belts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Safety belts. 169.723 Section 169.723 Shipping COAST... Control, Miscellaneous Systems, and Equipment § 169.723 Safety belts. Each vessel must carry a harness type safety belt conforming to Offshore Racing Council (ORC) standards for each person on watch or...

32 CFR 723.8 - Staff action.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Staff action. 723.8 Section 723.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL BOARD FOR CORRECTION OF NAVAL RECORDS § 723.8 Staff action. (a) Transmittal of final decisions granting relief. (1) If the final...

32 CFR 723.8 - Staff action.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Staff action. 723.8 Section 723.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL BOARD FOR CORRECTION OF NAVAL RECORDS § 723.8 Staff action. (a) Transmittal of final decisions granting relief. (1) If the final...

32 CFR 723.8 - Staff action.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Staff action. 723.8 Section 723.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL BOARD FOR CORRECTION OF NAVAL RECORDS § 723.8 Staff action. (a) Transmittal of final decisions granting relief. (1) If the final...

32 CFR 723.8 - Staff action.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Staff action. 723.8 Section 723.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL BOARD FOR CORRECTION OF NAVAL RECORDS § 723.8 Staff action. (a) Transmittal of final decisions granting relief. (1) If the final...

32 CFR 723.8 - Staff action.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Staff action. 723.8 Section 723.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL BOARD FOR CORRECTION OF NAVAL RECORDS § 723.8 Staff action. (a) Transmittal of final decisions granting relief. (1) If the final...

Where was the Iron Synthesized in Cassiopeia A?

NASA Technical Reports Server (NTRS)

Hwang, Una; Laming, J. Martin

2003-01-01

We investigate the properties of Fe-rich knots on the east limb of the Cassiopeia A supernova remnant observed with Chandra/AXAF CCD Imaging Spectrometer (ACIS). Using analysis methods developed in a companion paper, we constrain the ejecta density profile and the Lagrangian mass coordinates of the knots from their fitted ionization age and electron temperature. Fe-rich knots which also have strong emission from Si, S, Ar, and Ca are clustered around mass coordinates q approx. equal to 0.35 - 0.4 in the shocked ejecta of 2 solar masses; this places them 0.7 - 0.8 solar masses out from the center (or 2 - 2.1 solar masses, allowing for the mass of a compact object). We also find an Fe clump that is evidently devoid of line emission from lower mass elements, as would be expected for a region that had undergone alpha-rich freeze out. This clump has a similar mass coordinate to the other Fe knots.

A neutron star with a carbon atmosphere in the Cassiopeia A supernova remnant.

PubMed

Ho, Wynn C G; Heinke, Craig O

2009-11-05

The surface of hot neutron stars is covered by a thin atmosphere. If there is accretion after neutron-star formation, the atmosphere could be composed of light elements (H or He); if no accretion takes place or if thermonuclear reactions occur after accretion, heavy elements (for example, Fe) are expected. Despite detailed searches, observations have been unable to confirm the atmospheric composition of isolated neutron stars. Here we report an analysis of archival observations of the compact X-ray source in the centre of the Cassiopeia A supernova remnant. We show that a carbon atmosphere neutron star (with low magnetic field) produces a good fit to the spectrum. Our emission model, in contrast with others, implies an emission size consistent with theoretical predictions for the radius of neutron stars. This result suggests that there is nuclear burning in the surface layers and also identifies the compact source as a very young ( approximately 330-year-old) neutron star.

Image of the Supernova Remnant Cassiopeia A Taken by the High Energy Astronomy Observatory (HEAO)-2

NASA Technical Reports Server (NTRS)

1980-01-01

This x-ray photograph of the Supernova remnant Cassiopeia A, taken with the High Energy Astronomy Observatory (HEAO) 2/Einstein Observatory, shows that the regions with fast moving knots of material in the expanding shell are bright and clear. A faint x-ray halo, just outside the bright shell, is interpreted as a shock wave moving ahead of the expanding debris. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. Shortly after launch, the HEAO-2 was nicknamed the Einstein Observatory by its scientific experimenters in honor of the centernial of the birth of Albert Einstein, whose concepts of relativity and gravitation have influenced much of modern astrophysics, particularly x-ray astronomy. The HEAO-2, designed and developed by TRW, Inc. under the project management of the Marshall Space Flight Center, was launched aboard an Atlas/Centaur launch vehicle on November 13, 1978.

Image of the Supernova Cassiopeia Taken by the High Energy Astronomy Observatory (HEAO)-2

NASA Technical Reports Server (NTRS)

1980-01-01

This supernova in the constellation Cassiopeia was observed by Tycho Brahe in 1572. In this x-ray image from the High Energy Astronomy Observatory (HEAO-2/Einstein Observatory produced by nearly a day of exposure time, the center region appears filled with emissions that can be resolved into patches or knots of material. However, no central pulsar or other collapsed object can be seen. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. Shortly after launch, the HEAO-2 was nicknamed the Einstein Observatory by its scientific experimenters in honor of the centernial of the birth of Albert Einstein, whose concepts of relativity and gravitation have influenced much of modern astrophysics, particularly x-ray astronomy. The HEAO-2, designed and developed by TRW, Inc. under the project management of the Marshall Space Flight Center, was launched aboard an Atlas/Centaur launch vehicle on November 13, 1978.

Venusian arachnoids revisited

NASA Astrophysics Data System (ADS)

Kostama, V.-P.; Tormanen, T.

The Venusian volcano-tectonic structures have been subject to many classification and characterisation schemes. Several structure-types have been identified (e.g. coronae, novae, arachnoids, calderas, and corona-novae). Of these groups, the relationship of arachnoids and coronae has been complicated, and is a subject to much debate. Some previous works and studies have fused these two categories together, and even promoted the view of non-existence of arachnoids at times. However, based on the recognisable differences in morphology and other characteristics (e.g. size, topography, volcanism), they should be treated as a separate class of structures. In our first global study of the volcano-tectonic features, we found 96 arachnoids [1, 2]. During the reanalysis of the features as a by-product of another study, the arachnoid population was re-evalueted, and more importantly, the identification criteria was rechecked. The revised population increases the arachnoid number to 130 features. The work also produced many examples of features that can be considered as transitional forms between different morphological groups. [1] Kostama, V.-P., M. Aittola, LPSC XXXII, Abstract#1185, 2001a. [2] Kostama, V.-P., M. Aittola, The Catalogue of Venusian Arachnoids, Coronae and Novae, http://cc.oulu.fi/tati/JR/Venus/volcanotectonics/catalogue.html, 2001b.

Gamma-ray emission from globular clusters. Shock high energy emission from the Be-Star/Pulsar System PSR 1259-63. Echoes in x-ray novae

NASA Technical Reports Server (NTRS)

Kaaret, Philip

1995-01-01

This grant covers work on the Compton phase 3 investigation, 'Shock High Energy Emission from the Be- Star/Pulsar System PSR 1259-63' and cycle 4 investigations 'Diffuse Gamma-Ray Emission at High Latitudes' and 'Echoes in X-Ray Novae'. Work under the investigation 'Diffuse Gamma-Ray Emission at High Latitudes' has lead to the publication of a paper (attached), describing gamma-ray emissivity variations in the northern galactic hemisphere. Using archival EGRET data, we have found a large irregular region of enhanced gamma-ray emissivity at energies greater 100 MeV. This is the first observation of local structure in the gamma-ray emissivity. Work under the investigation 'Echoes in X-Ray Novae' is proceeding with analysis of data from OSSE from the transient source GRO J1655-40. The outburst of this source last fall triggered this Target of Opportunity investigation. Preliminary spectral analysis shows emission out to 600 keV and a pure power low spectrum with no evidence of an exponential cutoff. Work is complete on the analysis of BATSE data from the Be-Star/Pulsar Sustem PSR 1259-63.

The HEAO-A2 soft X-ray survey of cataclysmic variable stars - EX Hydrae during optical quiescence

NASA Technical Reports Server (NTRS)

Cordova, F. A.; Riegler, G. R.

1979-01-01

Results are reported for HEAO A2 soft X-ray (below 2 keV) scanning observations of the southern dwarf nova EX Hya. An X-ray light curve is presented which shows no apparent orbital modulation. The best-fitting spectral parameters are derived for the source, and the observations are compared with the spectral behavior of the dwarf nova SS Cyg during optical quiescence. The results are discussed in terms of models for X-ray production by accreting white dwarfs.

Multiwavelength Modeling of Nove Atmospheres

NASA Technical Reports Server (NTRS)

Huschildt, P. H.

2001-01-01

LMC 1988 #1 was a slow, CO type, dust forming classical nova. It was the first extragalactic nova to be observed with the IUE satellite. We have successfully fitted observed ultraviolet and optical spectra of LMC 1988 #1 taken within the first two months of its outburst (when the atmosphere was still optically thick) with synthetic spectra computed using PHOENIX nova model atmospheres. The synthetic spectra reproduce most of the features seen in the spectra and provide V band magnitudes consistent with the observed light curve. The fits are improved by increasing the CNO abundances to 10 times the solar values. The bolometric luminosity of LMC 1988 #1 was approximately constant at 2 x 10(exp 38) ergs per second at a distance of 47.3 kpc for the first 2 months of the outburst until the formation of the dust shell.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afanasieva, L.; Blackmon, J. C.; Deibel, C. M.

Background: The 31S(p,gamma) 32Cl reaction becomes important for sulfur production in novae if the P-31(p, alpha)Si-28 reaction rate is somewhat greater than currently accepted. The rate of the S-31(p,gamma) Cl-32 reaction is uncertain, primarily due to the properties of resonances at E-c.m. = 156 and 549 keV. Purpose: We precisely determined the excitation energies of states in Cl-32 through high-resolution. spectroscopy including the two states most important for the S-31(p,gamma) Cl-32 reaction at nova temperatures. Method: Excited states in Cl-32 were populated using the B-10(Mg-24, 2n) Cl-32 reaction with a Mg-24 beam from the ATLAS facility at Argonne National Laboratory.more » The reaction channel of interest was selected using recoils in the Fragment Mass Analyzer, and we determined precise level energies by detecting. rays with Gammasphere. Results: We also observed. rays from the decay of six excited states in Cl-32. The excitation energies for two unbound levels at E-x = 1738.1 (6) keV and 2130.5 (10) keV were determined and found to be in agreement with a previous high-precision measurement of the S-32(He-3, t) Cl-32 reaction [1]. Conclusions: An updated 31S(p,gamma) Cl-32 reaction rate is presented. With the excitation energies of important levels firmly established, the dominant uncertainty in the reaction rate at nova temperatures is due to the strength of the resonance corresponding to the 2131-keV state in Cl-32.« less

32 CFR 723.5 - Hearing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Hearing. 723.5 Section 723.5 National Defense... § 723.5 Hearing. (a) Convening of board. The Board will convene, recess and adjourn at the call of the Chair or Acting Chair. (b) Conduct of hearing. (1) The hearing shall be conducted by the Chair or Acting...

32 CFR 723.5 - Hearing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Hearing. 723.5 Section 723.5 National Defense... § 723.5 Hearing. (a) Convening of board. The Board will convene, recess and adjourn at the call of the Chair or Acting Chair. (b) Conduct of hearing. (1) The hearing shall be conducted by the Chair or Acting...

40 CFR 141.723 - Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... deficiencies identified in sanitary surveys performed by EPA. 141.723 Section 141.723 Protection of Environment... REGULATIONS Enhanced Treatment for Cryptosporidium Requirements for Sanitary Surveys Performed by Epa § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by...

40 CFR 141.723 - Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

Code of Federal Regulations, 2014 CFR

2014-07-01

... deficiencies identified in sanitary surveys performed by EPA. 141.723 Section 141.723 Protection of Environment... REGULATIONS Enhanced Treatment for Cryptosporidium Requirements for Sanitary Surveys Performed by Epa § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by...

40 CFR 141.723 - Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

Code of Federal Regulations, 2013 CFR

2013-07-01

... deficiencies identified in sanitary surveys performed by EPA. 141.723 Section 141.723 Protection of Environment... REGULATIONS Enhanced Treatment for Cryptosporidium Requirements for Sanitary Surveys Performed by Epa § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by...

40 CFR 141.723 - Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

Code of Federal Regulations, 2012 CFR

2012-07-01

... deficiencies identified in sanitary surveys performed by EPA. 141.723 Section 141.723 Protection of Environment... REGULATIONS Enhanced Treatment for Cryptosporidium Requirements for Sanitary Surveys Performed by Epa § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by...

40 CFR 141.723 - Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... deficiencies identified in sanitary surveys performed by EPA. 141.723 Section 141.723 Protection of Environment... REGULATIONS Enhanced Treatment for Cryptosporidium Requirements for Sanitary Surveys Performed by Epa § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by...

12 CFR 723.10 - What waivers are available?

Code of Federal Regulations, 2012 CFR

2012-01-01

... 12 Banks and Banking 7 2012-01-01 2012-01-01 false What waivers are available? 723.10 Section 723.10 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS MEMBER BUSINESS LOANS § 723.10 What waivers are available? You may seek a waiver for a category of loans in any of...

47 CFR 7.23 - Actions by the Commission on its own motion.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 1 2012-10-01 2012-10-01 false Actions by the Commission on its own motion. 7.23 Section 7.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Enforcement § 7.23 Actions by the...

47 CFR 7.23 - Actions by the Commission on its own motion.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 1 2013-10-01 2013-10-01 false Actions by the Commission on its own motion. 7.23 Section 7.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Enforcement § 7.23 Actions by the...

47 CFR 7.23 - Actions by the Commission on its own motion.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 1 2014-10-01 2014-10-01 false Actions by the Commission on its own motion. 7.23 Section 7.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Enforcement § 7.23 Actions by the...

Familial hypertrophic cardiomyopathy: functional effects of myosin mutation R723G in cardiomyocytes.

PubMed

Kraft, Theresia; Witjas-Paalberends, E Rosalie; Boontje, Nicky M; Tripathi, Snigdha; Brandis, Almuth; Montag, Judith; Hodgkinson, Julie L; Francino, Antonio; Navarro-Lopez, Francisco; Brenner, Bernhard; Stienen, Ger J M; van der Velden, Jolanda

2013-04-01

Familial Hypertrophic Cardiomyopathy (FHC) is frequently caused by mutations in the β-cardiac myosin heavy chain (β-MyHC). To identify changes in sarcomeric function triggered by such mutations, distinguishing mutation effects from other functional alterations of the myocardium is essential. We previously identified a direct effect of mutation R723G (MyHC723) on myosin function in slow Musculus soleus fibers. Here we investigate contractile features of left ventricular cardiomyocytes of FHC-patients with the same MyHC723-mutation and compare these to the soleus data. In mechanically isolated, triton-permeabilized MyHC723-cardiomyocytes, maximum force was significantly lower but calcium-sensitivity was unchanged compared to donor. Conversely, MyHC723-soleus fibers showed significantly higher maximum force and reduced calcium-sensitivity compared to controls. Protein phosphorylation, a potential myocardium specific modifying mechanism, might account for differences compared to soleus fibers. Analysis revealed reduced phosphorylation of troponin I and T, myosin-binding-protein C, and myosin-light-chain 2 in MyHC723-myocardium compared to donor. Saturation of protein-kinaseA phospho-sites led to comparable, i.e., reduced MyHC723-calcium-sensitivity in cardiomyocytes as in M. soleus fibers, while maximum force remained reduced. Myofibrillar disarray and lower density of myofibrils, however, largely account for reduced maximum force in MyHC723-cardiomyocytes. The changes seen when phosphorylation of sarcomeric proteins in myocardium of affected patients is matched to control tissue suggest that the R723G mutation causes reduced Ca(++)-sensitivity in both cardiomyocytes and M. soleus fibers. In MyHC723-myocardium, however, hypophosphorylation can compensate for the reduced calcium-sensitivity, while maximum force generation, lowered by myofibrillar deficiency and disarray, remains impaired, and may only be compensated by hypertrophy. Copyright © 2013 Elsevier Ltd. All rights reserved.

Early evolution of the extraordinary Nova Delphini 2013 (V339 Del)

NASA Astrophysics Data System (ADS)

Skopal, A.; Drechsel, H.; Tarasova, T.; Kato, T.; Fujii, M.; Teyssier, F.; Garde, O.; Guarro, J.; Edlin, J.; Buil, C.; Antao, D.; Terry, J.-N.; Lemoult, T.; Charbonnel, S.; Bohlsen, T.; Favaro, A.; Graham, K.

2014-09-01

Aims: We determine the temporal evolution of the luminosity (LWD), radius (RWD) and effective temperature (Teff) of the white dwarf (WD) pseudophotosphere of V339 Del from its discovery to around day 40. Another main objective was studying the ionization structure of the ejecta. Methods: These aims were achieved by modelling the optical/near-IR spectral energy distribution (SED) using low-resolution spectroscopy (3500-9200 Å), UBVRCIC and JHKLM photometry. Important insights in the physical conditions of the ejecta were gained from an analysis of the evolution of the Hα and Raman-scattered 6825 Å O vi line using medium-resolution spectroscopy (R ~ 10 000). Results: During the fireball stage (Aug. 14.8-19.9, 2013), Teff was in the range of 6000-12 000 K, RWD was expanding non-uniformly in time from ~66 to ~300 (d/ 3 kpc) R⊙, and LWD was super-Eddington, but not constant. Its maximum of ~9 × 1038 (d/ 3 kpc)2 erg s-1 occurred around Aug. 16.0, at the maximum of Teff, half a day before the visual maximum. After the fireball stage, a large emission measure of 1.0-2.0 × 1062 (d/ 3 kpc)2 cm-3 constrained the lower limit of LWD to be well above the super-Eddington value. The mass of the ionized region was a few × 10-4 M⊙, and the mass-loss rate was decreasing from ~5.7 (Aug. 22) to ~0.71 × 10-4 M⊙ yr-1 (Sept. 20). The evolution of the Hα line and mainly the transient emergence of the Raman-scattered O vi 1032 Å line suggested a biconical ionization structure of the ejecta with a disk-like H i region persisting around the WD until its total ionization, around day 40. On Sept. 20 (day 35), the model SED indicated a dust emission component in the spectrum. The dust was located beyond the H i zone, where it was shielded from the hard, ≳105 K, radiation of the burning WD at that time. Conclusions: Our extensive spectroscopic observations of the classical nova V339 Del allowed us to map its evolution from the very early phase after its explosion. It is evident that the nova was not evolving according to the current theoretical prediction. The unusual non-spherically symmetric ejecta of nova V339 Del and its extreme physical conditions and evolution during and after the fireball stage represent interesting new challenges for the theoretical modelling of the nova phenomenon. Based on data collected by amateur astronomers.

The CERGA Small Interferometer

NASA Astrophysics Data System (ADS)

Koechlin, L.; di Benedetto, G. P.; Thom, C.; Nisenson, P.

Contents: 1. Stellar diameters at λ = 0.6 μm (1985 - 86). 2. Stellar diameters at λ = 2.2 μm and 1.6 μm. 3. γ Cassiopeiae envelope in the Hα emission line. 4. Observations of α Cyg with the PAPA detector at λ = 0.6 μm.

12 CFR 723.20 - How can a state supervisory authority develop and enforce a member business loan regulation?

Code of Federal Regulations, 2010 CFR

2010-01-01

... state regulation minimizes the risk and accomplishes the overall objectives of NCUA's member business... and enforce a member business loan regulation? 723.20 Section 723.20 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS MEMBER BUSINESS LOANS § 723.20 How can a state...

12 CFR 723.12 - What will NCUA do with my waiver request?

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false What will NCUA do with my waiver request? 723.12 Section 723.12 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS MEMBER BUSINESS LOANS § 723.12 What will NCUA do with my waiver request? Your Regional Director...

32 CFR 723.7 - Action by the Secretary.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Action by the Secretary. 723.7 Section 723.7... NAVAL RECORDS § 723.7 Action by the Secretary. (a) General. The record of proceedings, except in cases... hearing, will be forwarded to the Secretary who will direct such action as he or she determines to be...

12 CFR 723.3 - What are the requirements for construction and development lending?

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false What are the requirements for construction and development lending? 723.3 Section 723.3 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS... development lending? Except as provided in § 723.4 or unless your Regional Director grants a waiver, loans...

12 CFR 702.104 - Risk portfolios defined.

Code of Federal Regulations, 2010 CFR

2010-01-01

... or mature within the next five (5) years, and exclusive of all member business loans (as defined in 12 CFR 723.1 or as approved under 12 CFR 723.20); (b) Member business loans outstanding. All member business loans as defined in 12 CFR 723.1 or as approved under 12 CFR 723.20; (c) Investments. Investments...

Masses of the visual components and black holes in X-ray novae: Effects of proximity of the components

NASA Astrophysics Data System (ADS)

Petrov, V. S.; Antokhina, E. A.; Cherepashchuk, A. M.

2017-05-01

It is shown that the approximation of the complex, tidally distorted shape of a star as a circular disc with local line profiles and a linear limb-darkening law, which is usually applied when deriving equatorial stellar rotation velocities from line profiles, leads to overestimation of the equatorial velocity V rot sin i and underestimation of the component mass ratio q = M x / M v . A formula enabling correction of the effect of these simplifying assumptions on the shape of a star is used to re-determine the mass ratios q and the masses of the black holes M x and visual components M v in low-mass X-ray binary systems containing black holes. Taking into account the tidal-rotational distortion of the stellar shape can significantly increase the mass ratios q = M x / M v , reducing M v , while M x changes only slightly. The resulting distribution of M v attains its maximum near M v ≃ 0.35 M ⊙, in disagreement with the results of population synthesis computations realizing standard models for Galactic X-ray novae with black holes. Possible ways to overcome this inconsistency are discussed. The derived distribution of M x also differs strongly from the mass distribution for massive stars in the Galaxy.

Optical Photometry of the Nova Outburst TCP J04432130+4721280 (V392 Per)

NASA Astrophysics Data System (ADS)

Konyves-Toth, R.; Csak, B.; Pal, A.; Vinko, J.

2018-05-01

We obtained new photometric observations of TCP J04432130+4721280 (V392 Per, ATel #11588, #11590), R.A = 04:43:21.38, Dec = +47:21:25.9, on 2018-04-30.80 UT. The data were taken with the 60/90 cm Schmidt telescope at Konkoly Observatory, Piszkesteto, Hungary.

Ultraviolet spectroscopy of symbiotic nova V1016 Cyg with IUE and HST

NASA Astrophysics Data System (ADS)

Sanad, M. R.

2017-04-01

We present International Ultraviolet Explorer (IUE) & Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) observations of the symbiotic nova V1016 Cyg through the period 1978 - 2000. Four spectra at different times revealing the changes in line fluxes are presented. The outflow velocity of the emitting region was calculated to be 900-2000 km s-1 (FWHM). The reddening of V1016 Cyg was determined from 2200 Å absorption feature to be E (B-V) = 0.36 ± 0.02. We calculated the fluxes of CIV 1550 Å & CIII] 1909 Å emission lines produced in a stellar wind from the hot white dwarf. We determined the average wind mass loss rate to be ˜2.3 × 10-6 M⊙, the average temperature of the emitting region to be ˜1.3 × 105 K, and an average ultraviolet luminosity to be ˜2 × 1035 erg s-1. The results show that there are modulations of line fluxes with time. We attributed these spectral modulations to the changes of density and temperature in the emitting region as a result of the variable stellar wind.

Muon Neutrino Disappearance in NOvA with a Deep Convolutional Neural Network Classifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocco, Dominick Rosario

2016-03-01

The NuMI Off-axis Neutrino Appearance Experiment (NOvA) is designed to study neutrino oscillation in the NuMI (Neutrinos at the Main Injector) beam. NOvA observes neutrino oscillation using two detectors separated by a baseline of 810 km; a 14 kt Far Detector in Ash River, MN and a functionally identical 0.3 kt Near Detector at Fermilab. The experiment aims to provide new measurements of Δm 2 and θ23 and has potential to determine the neutrino mass hierarchy as well as observe CP violation in the neutrino sector. Essential to these analyses is the classification of neutrino interaction events in NOvA detectors.more » Raw detector output from NOvA is interpretable as a pair of images which provide orthogonal views of particle interactions. A recent advance in the field of computer vision is the advent of convolutional neural networks, which have delivered top results in the latest image recognition contests. This work presents an approach novel to particle physics analysis in which a convolutional neural network is used for classification of particle interactions. The approach has been demonstrated to improve the signal efficiency and purity of the event selection, and thus physics sensitivity. Early NOvA data has been analyzed (2.74×10 20 POT, 14 kt equivalent) to provide new best- fit measurements of sin 2(θ23) = 0.43 (with a statistically-degenerate compliment near 0.60) and |Δm2 | = 2.48 × 10 -3 eV 2.« less

^2H(^18F,p)^19F Study at 6 MeV/u

NASA Astrophysics Data System (ADS)

Kozub, R. L.; Nesaraja, C. D.; Moazen, B. H.; Scott, J. P.; Bardayan, D. W.; Blackmon, J. C.; Gross, C. J.; Shapira, D.; Smith, M. S.; Batchelder, J. C.; Brune, C. R.; Champagne, A. E.; Sahin, L.; Cizewski, J. A.; Thomas, J. S.; Davinson, T.; Woods, P. J.; Greife, U.; Jewett, C.; Livesay, R. J.; Ma, Z.; Parker, P. D.

2003-04-01

The degree to which the (p,α) and (p,γ) reactions destroy ^18F at temperatures ˜1-4 x 10^8 K is important for understanding the synthesis of nuclei in nova explosions and for using ^18F as a monitor of nova mechanisms in gamma ray astronomy. The reactions are dominated by low-lying proton resonances near the ^18F+p threshold (E_x=6.411 MeV excitation energy in ^19Ne). To gain further information about these resonances, we have used the inverse ^18F(d,p)^19F neutron transfer reaction at the Holifield Radioactive Ion Beam Facility to selectively populate corresponding mirror states in ^19F. Proton angular distributions were measured for states in ^19F in the excitation energy range 0-9 MeV. Results and implications for the ^18F+p reactions and nuclear structure will be presented. ^1Supported by DOE. ^2ORNL is managed by UT-Battelle, LLC, for the USDOE.

The X-Ray Evolution of the Symbiotic Star V 407 Cygni During Its 2010 Outburst

NASA Technical Reports Server (NTRS)

Mukai, K.; Nelson, T.; Chomiuk, L.; Donato, D.; Sokoloski, J.

2011-01-01

We present a summary of Swift and Suzaku X-ray observations of the 2010 nova outburst of the symbiotic star, V 407 Cyg. The Suzaku spectrum obtained on day 30 indicates the presence of the supersoft component from the white dwarf surface, as well as optically thin component from the shock between the nova ejecta and the Mira wind. The Swift observations then allow us to track the evolution of both components from day 4 to day 150. Most notable is the sudden brightening of the optically think component around day 20. We identify this as the time when the blast wave reached the immediate vicinity of the photosphere of the Mira. We have developed a simplified model of the blast wave-wind interaction that can reproduce the gross features of the X-ray evolution of V407 Cyg. If the model is correct, the binary separation is likely to be large and the mass loss rate of the Mira is likely to be relatively low.

The X-Ray Evolution of the Symbiotic Star V407 Cygni During Its 2010 Outburst

NASA Technical Reports Server (NTRS)

Mukai, K.; Nelson, T.; Chomiuk, L.; Donato, D.; Sokoloski, J.

2011-01-01

We present a summary of Swift and Suzaku X-ray observations of the 2010 nova outburst of the symbiotic star, V407 Cyg. The Suzaku spectrum obtained on day 30 indicates the presence of the supersoft component from the white dwarf surface, as well as optically thin component from the shock between the nova ejecta and the Mira wind. The Swift observations then allow us to track the evolution of both components from day 4 to day 150. Most notable is the sudden brightening of the optically think component around day 20. We identify this as the time when the blast wave reached the immediate vicinity of the photosphere of the Mira. We have developed a simplified model of the blast wave-wind interaction that can reproduce the gross features of the X-ray evolution of V407 Cyg. If the model is correct, the binary separation is likely to be large and the mass loss rate of the Mira is likely to be relatively low.

The supersoft X-ray source in V5116 Sagittarii. I. The high resolution spectra

NASA Astrophysics Data System (ADS)

Sala, G.; Ness, J. U.; Hernanz, M.; Greiner, J.

2017-05-01

Context. Classical nova explosions occur on the surface of an accreting white dwarf in a binary system. After ejection of a fraction of the envelope and when the expanding shell becomes optically thin to X-rays, a bright source of supersoft X-rays arises, powered by residual H burning on the surface of the white dwarf. While the general picture of the nova event is well established, the details and balance of accretion and ejection processes in classical novae are still full of unknowns. The long-term balance of accreted matter is of special interest for massive accreting white dwarfs, which may be promising supernova Ia progenitor candidates. Nova V5116 Sgr 2005b was observed as a bright and variable supersoft X-ray source by XMM-Newton in March 2007, 610 days after outburst. The light curve showed a periodicity consistent with the orbital period. During one third of the orbit the luminosity was a factor of seven brighter than during the other two thirds of the orbital period. Aims: In the present work we aim to disentangle the X-ray spectral components of V5116 Sgr and their variability. Methods: We present the high resolution spectra obtained with XMM-Newton RGS and Chandra LETGS/HRC-S in March and August 2007. Results: The grating spectrum during the periods of high-flux shows a typical hot white dwarf atmosphere dominated by absorption lines of N VI and N VII. During the low-flux periods, the spectrum is dominated by an atmosphere with the same temperature as during the high-flux period, but with several emission features superimposed. Some of the emission lines are well modeled with an optically thin plasma in collisional equilibrium, rich in C and N, which also explains some excess in the spectra of the high-flux period. No velocity shifts are observed in the absorption lines, with an upper limit set by the spectral resolution of 500 km s-1, consistent with the expectation of a non-expanding atmosphere so late in the evolution of the post-nova. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Nuclear reaction rate uncertainties and the 22Ne( p,gamma)23Na reaction: Classical novae and globular clusters

NASA Astrophysics Data System (ADS)

Kelly, Keegan John

The overall theme of this thesis is the advancement of nuclear astrophysics via the analysis of stellar processes in the presence of varying levels of precision in the available nuclear data. With regard to classical novae, the level of mixing that occurs between the outer layers of the white dwarf core and the solar accreted material in oxygen-neon novae is presently undetermined by stellar models, but the nuclear data relevant to these explosive phenomena are fairly precise. This precision allowed for the identification of a series of elemental ratios indicative of the level of mixing occurring in novae. Direct comparisons of the modelled elemental ratios to observations showed that there is likely to be much less of this mixing than was previously assumed. Thus, our understanding of classical novae was altered via the investigation of the nuclear reactions relevant to this phenomenon. However, this level of experimental precision is rare and large nuclear reaction uncertainties can hinder our understanding of certain astrophysical phenomena. For example, it is commonly believed that uncertainties in the 22Ne(p,g)23Na reaction rate at temperatures relevant to thermally-pulsing asymptotic giant branch stars are largely responsible for our inability to explain the observed sodium-oxygen anti-correlation in globular clusters. With this motivation, resonances in the 22Ne(p,g) 23Na reaction at E_{c.m.} = 458, 417, 178, and 151 keV were measured. The direct-capture contribution was also measured at E_{lab} = 425 keV. It was determined that the 22Ne(p,g)23Na reaction rate in the astrophysically relevant temperature range is dominated by the resonances at 178 and 151 keV and that the total reaction rate is greater than the previously assumed rate by a factor of approximately ˜40 at 0.15 GK. This increased reaction rate impacts the expected nucleosynthesis that occurs in these stars and will shed light onto the origin of this anti-correlation as it is incorporated into sophisticated stellar models in the future. In both of these cases the available nuclear data were used to probe stellar processes. This analysis of stellar processes through nuclear reactions is an extremely useful technique that is crucial for the advancement of astrophysics.

Polyunsaturated fatty acids are potent openers of human M-channels expressed in Xenopus laevis oocytes.

PubMed

Liin, S I; Karlsson, U; Bentzen, B H; Schmitt, N; Elinder, F

2016-09-01

Polyunsaturated fatty acids have been reported to reduce neuronal excitability, in part by promoting inactivation of voltage-gated sodium and calcium channels. Effects on neuronal potassium channels are less explored and experimental data ambiguous. The aim of this study was to investigate anti-excitable effects of polyunsaturated fatty acids on the neuronal M-channel, important for setting the resting membrane potential in hippocampal and dorsal root ganglion neurones. Effects of fatty acids and fatty acid analogues on mouse dorsal root ganglion neurones and on the human KV 7.2/3 channel expressed in Xenopus laevis oocytes were studied using electrophysiology. Extracellular application of physiologically relevant concentrations of the polyunsaturated fatty acid docosahexaenoic acid hyperpolarized the resting membrane potential (-2.4 mV by 30 μm) and increased the threshold current to evoke action potentials in dorsal root ganglion neurones. The polyunsaturated fatty acids docosahexaenoic acid, α-linolenic acid and eicosapentaenoic acid facilitated opening of the human M-channel, comprised of the heteromeric human KV 7.2/3 channel expressed in Xenopus oocytes, by shifting the conductance-vs.-voltage curve towards more negative voltages (by -7.4 to -11.3 mV by 70 μm). Uncharged docosahexaenoic acid methyl ester and monounsaturated oleic acid did not facilitate opening of the human KV 7.2/3 channel. These findings suggest that circulating polyunsaturated fatty acids, with a minimum requirement of multiple double bonds and a charged carboxyl group, dampen excitability by opening neuronal M-channels. Collectively, our data bring light to the molecular targets of polyunsaturated fatty acids and thus a possible mechanism by which polyunsaturated fatty acids reduce neuronal excitability. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Microstructure evolution of recrystallized Zircaloy-4 under charged particles irradiation

NASA Astrophysics Data System (ADS)

Gaumé, M.; Onimus, F.; Dupuy, L.; Tissot, O.; Bachelet, C.; Mompiou, F.

2017-11-01

Recrystallized zirconium alloys are used as nuclear fuel cladding tubes of Pressurized Water Reactors. During operation, these alloys are submitted to fast neutron irradiation which leads to their in-reactor deformation and to a change of their mechanical properties. These phenomena are directly related to the microstructure evolution under irradiation and especially to the formation of -type dislocation loops. In the present work, the radiation damage evolution in recrystallized Zircaloy-4 has been studied using charged particles irradiation. The loop nucleation and growth kinetics, and also the helical climb of linear dislocations, were observed in-situ using a High Voltage Electron Microscope (HVEM) under 1 MeV electron irradiation at 673 and 723 K. In addition, 600 keV Zr+ ion irradiations were conducted at the same temperature. Transmission Electron Microscopy (TEM) characterizations have been performed after both types of irradiations, and show dislocation loops with a Burgers vector belonging to planes close to { 10 1 bar 0 } first order prismatic planes. The nature of the loops has been characterized. Only interstitial dislocation loops have been observed after ion irradiation at 723 K. However, after electron irradiation conducted at 673 and 723 K, both interstitial and vacancy loops were observed, the proportion of interstitial loops increasing as the temperature is increased. The loop growth kinetics analysis shows that as the temperature increases, the loop number density decreases and the loop growth rate tends to increase. An increase of the flux leads to an increase of the loop number density and a decrease of the loop growth rate. The results are compared to previous works and discussed in the light of point defects diffusion.

The TeMPEST Transit Search: Preliminary Results

NASA Astrophysics Data System (ADS)

Baliber, N. R.; Cochran, W. D.

The Texas, McDonald Photometric Extrasolar Search for Transits, TeMPEST, is a photometric search for transits of extrasolar giant planets orbiting at distances less than approximately 0.1 AU to their parent stars. This survey is being conducted with the McDonald Observatory 0.76 meter Prime Focus Camera (PFC), which provides a 46.2 x 46.2 arcsec field of view. From August through December, 2001, we obtained our first full season of data on two fields in the Galactic plane, one in the constellation Cassiopeia and the other in Camelopardus. In these two fields, V-band time-series photometry with a cadence of about 9 minutes has been performed on over 5000 stars with sufficient precision, better than 0.01 mag, to detect transits of close-orbiting Jovian planets. We present representative light curves from variable stars and an eclipsing system from our 2001 data. The TeMPEST project is funded by the NASA Origins program.

Comparative scanning electron microscope analysis of diode laser and desensitizing toothpastes for evaluation of efficacy of dentinal tubular occlusion.

PubMed

Reddy, Guntakala Vikram; Akula, Sushma; Malgikar, Suryakanth; Babu, Palaparthy Raja; Reddy, Gooty Jagadish; Josephin, Johnson Juliet

2017-01-01

The present study aims to evaluate the efficacy of diode laser alone and in combination with desensitizing toothpastes in occluding dentinal tubules (both partially occluded and completely occluded tubules) by scanning electron microscope (SEM). Fifty human teeth were extracted, cervical cavities were prepared and etched with 17% ethylenediaminetetraacetic acid, and smear layer was removed to expose the tubules. The teeth were divided into five groups: Group I - Application of NovaMin-formulated toothpaste, Group II - Application of Pro-Argin ™ -formulated toothpaste, Group III - Application of diode laser in noncontact mode, Group IV - NovaMin-formulated toothpaste followed by laser irradiation, and Group V - Pro-Argin ™ -formulated toothpaste followed by laser irradiation. After treatment, quantitative analysis of occluded dentinal tubules was done by SEM analysis. The mean values of percentages of total occlusion of dentinal tubules in Groups I, II, III, IV, and V were 92.73% ± 1.38, 90.67% ± 1.86, 96.57% ± 0.64, 97.3% ± 0.68, and 96.9% ± 6.08, respectively. Addition of diode laser (Groups III, IV, and V) yielded a significant occlusion of the dentinal tubules when compared to desensitizing toothpastes alone (Groups I and II). Diode laser (Group III) has shown more efficacy in occluding dentinal tubules when compared with desensitizing toothpastes which was statistically significant ( P < 0.05). Among the five groups, NovaMin + diode laser (Group IV) showed the highest percentage of occluded dentinal tubules.

Photoionisation modelling of Nova LMC 1990 #1

NASA Technical Reports Server (NTRS)

Dopita, M. A.; Meatheringham, S. J.; Sutherland, R.; Williams, R. E.; Starrfield, S.; Sonneborn, G.; Shore, S.

1992-01-01

Nova LMC 1990A was a very fast Ne-O-Mg nova, for which a particularly dense coverage of spectral observation in both the UV and optical was obtained. The data for the nebular phase were subjected to an analysis by the photoionization modeling code MAPPINGS 2. The following parameters were obtained: L(sub max) = 8 x 10(exp 4) solar luminosity, T(sub eff) = 2 x 10(exp 5) K and the mass of ejecta = 5/5 x 10(exp -5) solar mass. The abundnace ratios in the ejecta were similar to those obtained by Williams et al. (1985) in the case of V693 CrA 1981. The N/O ratio and the overabundance of Al is consistent with ourburst on a ONeMg white dwarf of mass approximately equal to 1.2 solar mass, but the super-Eddington luminosity, and amount of mass ejected presents some problems to theory.

Magnetic activity of red secondaries: clues from the outburst cycle variations of dwarf novae

NASA Astrophysics Data System (ADS)

Chinarova, L. L.

Photometric variations of 6 dwarf novae stars are studied based on the photographic observations from the Odessa, Moscow and Sonneberg plate collections and published visual monitoring data from the AFOEV database (Schweitzer E.: 1993, Bull. AFOEV, 64, 14). The moments of maxima are determined by using the "running parabola" fit (Andronov I.L., 1990, Kinematika Fizika Nebesn. Tel., v.6,,N 6, 87) with automatically determined filter half-width (Andronov I.L., 1997, As.Ap. Suppl., in press). All investigated stars exhibit significant changes not only from cycle-to-cycle, but from season-to-season as well. Secondary decade-scale cycles of smooth variations (Bianchini A., 1990, AJ 99, 1941) and abrupt switchings (Andronov I.L., Shakun L.I., 1990, ASS 169, 237) were interpreted by a solar-type activity of the red dwarf secondary in a binary system and may argue for existence of two different subgroups of the dwarf novae.

γ Cassiopeiae: an X-ray Be star with personality

NASA Astrophysics Data System (ADS)

Lopes de Oliveira, R.; Smith, M. A.; Motch, C.

2010-03-01

An exciting unsolved problem in the study of high energy processes of early type stars concerns the physical mechanism for producing X-rays near the Be star γ Cassiopeiae. By now we know that this source and several “γ Cas analogs” exhibit an unusual hard thermal X-ray spectrum, compared both to normal massive stars and the non-thermal emission of known Be/X-ray binaries. Also, its light curve is variable on almost all conceivable timescales. In this study we reanalyze a high dispersion spectrum obtained by Chandra in 2001 and combine it with the analysis of a new (2004) spectrum and light curve obtained by XMM-Newton. We find that both spectra can be fit well with 3-4 optically thin, thermal components consisting of a hot component having a temperature kTQ ˜ 12-14 keV, perhaps one with a value of ~2.4 keV, and two with well defined values near 0.6 keV and 0.11 keV. We argue that these components arise in discrete (almost monothermal) plasmas. Moreover, they cannot be produced within an integral gas structure or by the cooling of a dominant hot process. Consistent with earlier findings, we also find that the Fe abundance arising from K-shell ions is significantly subsolar and less than the Fe abundance from L-shell ions. We also find novel properties not present in the earlier Chandra spectrum, including a dramatic decrease in the local photoelectric absorption of soft X-rays, a decrease in the strength of the Fe and possibly of the Si K fluorescence features, underpredicted lines in two ions each of Ne and N (suggesting abundances that are ~1.5-3× and ~4× solar, respectively), and broadening of the strong Ne X Lyα and O VIII Lyα lines. In addition, we note certain traits in the γ Cas spectrum that are different from those of the fairly well studied analog HD 110432 - in this sense the stars have different “personalities.” In particular, for γ Cas the hot X-ray component remains nearly constant in temperature, and the photoelectric absorption of the X-ray plasmas can change dramatically. As found by previous investigators of γ Cas, changes in flux, whether occurring slowly or in rapidly evolving flares, are only seldomly accompanied by variations in hardness. Moreover, the light curve can show a “periodicity” that is due to the presence of flux minima that recur semiregularly over a few hours, and which can appear again at different epochs. This work is based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Ultraviolet observation of nova LMC 2012 with STIS/HST

NASA Astrophysics Data System (ADS)

Shore, S. N.; Schwarz, G.; Page, K.; Osborne, J. P.; Starrfield, S.; Walter, F.; Woodward, C. E.; Bode, M.; Ness, J.-U.

2012-05-01

Nova LMC 2012 (ATel #4002, #4043) was observed with STIS on the Hubble Space Telescope on 2012 May 7 (MJD 56055) at three settings with medium resolution (E140M, E230M, with exposure times of 724 sec per setting) covering 1150 - 3000 A. There is only one strong emission line in the entire spectral range: N V 1240 (S/N ~ 15, 0.5 A binning, integrated (not dereddened) flux of 1.2E-13 erg/s/cm^2, FWZI ~ 7500 km/s); the blue wing is blended with Ly-alpha absorption (MW+LMC).

Early Program Development

NASA Image and Video Library

1961-05-01

This artist's concept illustrates the Module Nova concept - Solid C-3 Basis. From 1960 to 1962, the Marshall Space Flight Center considered the Nova launch vehicle as a means to achieve a marned lunar landing with a direct flight to the Moon. Various configurations of the vehicle were examined. The latest configuration was a five-stage vehicle using eight F-1 engines in the first stage. Although the program was canceled after NASA planners selected the lunar/orbital rendezvous mode, the proposed F-1 engine would eventually be used in the Apollo Program to propel the first stage of the Saturn V launch vehicle.

Early Program Development

NASA Image and Video Library

1961-11-01

This artist's concept illustrates the Module Nova concept - Solid C-3 Basis. From 1960 to 1962, the Marshall Space Flight Center considered the Nova launch vehicle as a means to achieve a marned lunar landing with a direct flight to the Moon. Various configurations of the vehicle were examined. The latest configuration was a five-stage vehicle using eight F-1 engines in the first stage. Although the program was canceled after NASA planners selected the lunar/orbital rendezvous mode, the proposed F-1 engine would eventually be used in the Apollo Program to propel the first stage of the Saturn V launch vehicle.

Oscillations of Accretion Disks in Cataclysmic Variable Stars

NASA Astrophysics Data System (ADS)

Osaki, Y.

2013-12-01

The disk instability model for the outbursts of dwarf novae is reviewed, with particular attention given to the superoutburst of SU UMa stars. Two intrinsic instabilities in accretion disks of dwarf novae are known; the thermal instability and the tidal instability. The thermal-tidal instability model (abbreviated the TTI model), which combines these two instabilities, was first proposed in 1989 by Osaki (1989) to explain the superoutburst phenomenon of SU UMa stars. Recent Kepler observations of one SU UMa star, V1504 Cyg, have dramatically demonstrated that the superoutburst phenomenon of the SU UMa stars is explained by the thermal-tidal instability model.

γ spectroscopy of states in Cl 32 relevant for the S 31 ( p , γ ) Cl 32 reaction rate

DOE PAGES

Afanasieva, L.; Blackmon, J. C.; Deibel, C. M.; ...

2017-09-01

Background: The 31S(p,gamma) 32Cl reaction becomes important for sulfur production in novae if the P-31(p, alpha)Si-28 reaction rate is somewhat greater than currently accepted. The rate of the S-31(p,gamma) Cl-32 reaction is uncertain, primarily due to the properties of resonances at E-c.m. = 156 and 549 keV. Purpose: We precisely determined the excitation energies of states in Cl-32 through high-resolution. spectroscopy including the two states most important for the S-31(p,gamma) Cl-32 reaction at nova temperatures. Method: Excited states in Cl-32 were populated using the B-10(Mg-24, 2n) Cl-32 reaction with a Mg-24 beam from the ATLAS facility at Argonne National Laboratory.more » The reaction channel of interest was selected using recoils in the Fragment Mass Analyzer, and we determined precise level energies by detecting. rays with Gammasphere. Results: We also observed. rays from the decay of six excited states in Cl-32. The excitation energies for two unbound levels at E-x = 1738.1 (6) keV and 2130.5 (10) keV were determined and found to be in agreement with a previous high-precision measurement of the S-32(He-3, t) Cl-32 reaction [1]. Conclusions: An updated 31S(p,gamma) Cl-32 reaction rate is presented. With the excitation energies of important levels firmly established, the dominant uncertainty in the reaction rate at nova temperatures is due to the strength of the resonance corresponding to the 2131-keV state in Cl-32.« less

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.

Experimental study of β-delayed proton decay of Al23 for nucleosynthesis in novae

NASA Astrophysics Data System (ADS)

Saastamoinen, A.; Trache, L.; Banu, A.; Bentley, M. A.; Davinson, T.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Woods, P. J.; Äystö, J.

2011-04-01

The β-delayed γ and proton decay of Al23 has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A&M University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous β-decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the Al23 ground state at Ex=7803 keV in Mg23 was observed. Instead we assign the observed low-energy group Ep,c.m.=206 keV to the decay from a state that is 16 keV below the IAS. We measured both proton and gamma branches from the decay of this state at Ex=7787 keV in Mg23, which is a very rare case in the literature. Combining our data with its measured lifetime, we determine its resonance strength to be ωγ=1.4-0.4+0.5 meV. The value is in agreement with older direct measurements, but disagrees with a recent direct measurement. This state is the most important resonance for the radiative proton capture Na22(p,γ)Mg23 in some astrophysical environments, such as novae.

Evaluation of immunoreactivity of normal tissues from dogs, using monoclonal antibody B72.3.

PubMed

Clemo, F A; DeNicola, D B; Zimmermann, J L

1994-08-01

Monoclonal antibody (MAB) B72.3, which recognizes human tumor-associated glycoprotein-72, has immunoreactivity for malignant epithelial neoplasms in human beings and dogs. To further characterize the range of immunoreactivity of MAB B72.3 in canine tissues, MAB B72.3 and 2 other tumor-associated glycoprotein-72 antibodies (MAB CC49 and CC83) were tested against a wide spectrum of normal tissues from dogs. Immunoreactivity was detected, using an avidin-biotin-complex immunoperoxidase method. Monoclonal antibody B72.3 did not stain most types of normal canine tissues, but various types of epithelial cells within the gastrointestinal and respiratory tract mucosae, salivary gland, esophagus, epididymis, uterus, thymus, hair follicle, and apocrine glands of the anal sac had variable staining with MAB B72.3. A similar range of immunoreactivity in comparable types of normal tissues was seen for MAB CC49 and CC83; however, MAB CC49, but not MAB B72.3 and CC83, stained the endothelium of capillaries and small vessels in most normal tissues. Staining of frozen and paraffin-embedded tissues was similar. In conclusion, we found that MAB B72.3, CC49, and CC83 had selected immunoreactivity for specific types of normal canine epithelial cells, especially those involved with mucin production.

The Fall and the Rise of X-Rays from Dwarf Novae in Outburst: RXTE Observations of VW Hydri and WW Ceti

NASA Technical Reports Server (NTRS)

Fertig, D.; Mukai, K.; Nelson, T.; Cannizzo, J. K.

2011-01-01

In a dwarf nova, the accretion disk around the white dwarf is a source of ultraviolet, optical, and infrared photons, but is never hot enough to emit X-rays. Observed X-rays instead originate from the boundary layer between the disk and the white dwarf. As the disk switches between quiescence and outburst states, the 2-10 keV X-ray flux is usually seen to be anti-correlated with the optical brightness. Here we present RXTE monitoring observations of two dwarf novae, VW Hyi and WW Cet, confirming the optical/X-ray anti-correlation in these two systems. However, we do not detect any episodes of increased hard X-ray flux on the rise (out of two possible chances for WW Cet) or the decline (two for WW Cet and one for VW Hyi) from outburst, attributes that are clearly established in SS Cyg. The addition of these data to the existing literature establishes the fact that the behavior of SS Cyg is the exception, rather than the archetype as is often assumed. We speculate that only dwarf novae with a massive white dwarf may show these hard X-ray spikes.

Weak magnetic field, solid-envelope rotation, and wave-induced N-enrichment in the SPB star ζ Cassiopeiae

NASA Astrophysics Data System (ADS)

Briquet, M.; Neiner, C.; Petit, P.; Leroy, B.; de Batz, B.

2016-03-01

Aims: The main-sequence B-type star ζ Cassiopeiae is known as a N-rich star with a magnetic field discovered with the Musicos spectropolarimeter. We model the magnetic field of the star by means of 82 new spectropolarimetric observations of higher precision to investigate the field strength, topology, and effect. Methods: We gathered data with the Narval spectropolarimeter installed at Télescope Bernard Lyot (TBL; Pic du Midi, France) and applied the least-squares deconvolution technique to measure the circular polarisation of the light emitted from ζ Cas. We used a dipole oblique rotator model to determine the field configuration by fitting the longitudinal field measurements and by synthesizing the measured Stokes V profiles. We also made use of the Zeeman-Doppler imaging technique to map the stellar surface and to deduce the difference in rotation rate between the pole and equator. Results: ζ Cas exhibits a polar field strength Bpol of 100-150 G, which is the weakest polar field observed so far in a massive main-sequence star. Surface differential rotation is ruled out by our observations and the field of ζ Cas is strong enough to enforce rigid internal rotation in the radiative zone according to theory. Thus, the star rotates as a solid body in the envelope. Conclusions: We therefore exclude rotationally induced mixing as the cause of the surface N-enrichment. We discuss that the transport of chemicals from the core to the surface by internal gravity waves is the most plausible explanation for the nitrogen overabundance at the surface of ζ Cas. Based on observations obtained at the Télescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique (CNRS) of France.

Monitoring of V2487 Oph requested

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2016-10-01

Dr. Ashley Pagnotta (Louisiana State University) has requested AAVSO assistance in monitoring the recurrent nova V2487 Oph in order to catch and observe its next outburst. Pagnotta writes: "V2487 Oph is a recurrent nova that was first seen to erupt in 1998. During a search of the Harvard College Observatory plate archives for previous eruptions, we found one that was recorded in 1900. Based on the speed and magnitude of the eruption, and the coverage of the archival plates and other detection sources, we calculated how often V2487 Oph would have to erupt for us to have actually detected one random outburst on the plates, which is about once every 18-20 years (for more, Pagnotta et al. 2009AJ....138.1230P). As we are now 18 years from the previous (1998) eruption, we request regular AAVSO observations to help us detect the next eruption of V2487 Oph. Because V2487 Oph is a very fast nova, we are requesting a high cadence [when the outburst occurs. Previous outbursts have been as bright as V=9.5.]...Once the eruption has been confirmed (likely by other AAVSO observers, thanks to the flexibility of your observing programs), we will notify collaborators and invoke ToO observations to observe the eruption as comprehensively as possible." Observers are requested to make nightly observations in V or Clear. If V2487 Oph is brighter than V=17.5, please report the observation(s) to the AAVSO immediately and switch to multi-color (UBVRI or Sloan equivalents; Clear if other filters are not available) and high (fast) cadence time-series - exposures of a few minutes, with a S/N of at least 40-50. Continue at high cadence until the decline is underway. Time-series observations during the decline are not absolutely essential, but they would be useful to continue to look for flares and the late time dips that were seen in U Sco around days 41-61. Nightly observations as before should be continued until the star has faded to V=17.5, and then for two weeks m! ore. Finder charts with sequence may be created using the AAVS! O Variab le Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

On the Determination of Ejecta Structure and Explosion Asymmetry from the X-ray Knots of Cassiopeia A

NASA Technical Reports Server (NTRS)

Laming, J. Martin; Hwang, Una

2003-01-01

We present a detailed analysis of Chandra X-ray spectra from individual ejecta knots in the supernova remnant Cassiopeia A. The spectra are fitted to give the electron temperature T(sub e), and (single) ionization age n(sub e)t. These quantities are compared with the predictions of self similar hydrodynamic models incorporating time dependent ionization and radiation losses, and Coulomb electron-ion equilibration behind the reverse shock, for a variety of different ejecta density profiles described by a uniform density core and a power law envelope. We find that the ejecta close to the 'jet' region in the NE, but not actually in the jet itself, have a systematically shallower outer envelope than ejecta elsewhere in the remnant, and we interpret this as being due to more energy of the initial explosion being directed in this polar direction as opposed to equatorially. The degree of asymmetry we infer is at the low end of that generally modelled in asymmetric core-collapse simulations, and may be used to rule out highly asymmetric explosion models.

Dust masses for SN 1980K, SN1993J and Cassiopeia A from red-blue emission line asymmetries

NASA Astrophysics Data System (ADS)

Bevan, Antonia; Barlow, M. J.; Milisavljevic, D.

2017-03-01

We present Monte Carlo line transfer models that investigate the effects of dust on the very late time emission line spectra of the core-collapse supernovae SN 1980K and SN 1993J and the young core collapse supernova remnant Cassiopeia A. Their blueshifted emission peaks, resulting from the removal by dust of redshifted photons emitted from the far sides of the remnants, and the presence of extended red emission wings are used to constrain dust compositions and radii and to determine the masses of dust in the remnants. We estimate dust masses of between 0.08 and 0.15 M⊙ for SN 1993J at year 16, 0.12 and 0.30 M⊙ for SN 1980K at year 30 and ∼1.1 M⊙ for Cas A at year ∼330. Our models for the strong oxygen forbidden lines of Cas A require the overall modelled profiles to be shifted to the red by between 700 and 1000 km s-1, consistent with previous estimates for the shift of the dynamical centroid of this remnant.

Cassiopeia A supernova

NASA Image and Video Library

2017-12-08

NASA's Fermi Closes on Source of Cosmic Rays New images from NASA's Fermi Gamma-ray Space Telescope show where supernova remnants emit radiation a billion times more energetic than visible light. The images bring astronomers a step closer to understanding the source of some of the universe's most energetic particles -- cosmic rays. This composite shows the Cassiopeia A supernova remnant across the spectrum: Gamma rays (magenta) from NASA's Fermi Gamma-ray Space Telescope; X-rays (blue, green) from NASA's Chandra X-ray Observatory; visible light (yellow) from the Hubble Space Telescope; infrared (red) from NASA's Spitzer Space Telescope; and radio (orange) from the Very Large Array near Socorro, N.M. Credit: NASA/DOE/Fermi LAT Collaboration, CXC/SAO/JPL-Caltech/Steward/O. Krause et al., and NRAO/AUI For more information: www.nasa.gov/mission_pages/GLAST/news/cosmic-rays-source.... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

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

PubMed Central

Godon, Patrick; Sion, Edward M.; Starrfield, Sumner; Livio, Mario; Williams, Robert E.; Woodward, Charles E.; Kuin, Paul; Page, Kim L.

2018-01-01

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 ~10−5 M⊙ to 3.3 × 10−4 M⊙, and assuming a mass accretion rate of 10−8−10−7 M⊙ yr−1 for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B − V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ E(B−V) ≤ 0.50) and white dwarf mass (0.70 M⊙ ≤ Mwd ≤ 1.35 M⊙) the accreted mass is larger than the ejected mass. Only for a low reddening (~0.25 and smaller) combined with a large white dwarf mass (0.9 M⊙ and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening. PMID:29430290

High-cadence Multi-color Observations of the Dwarf Nova KSP-OT-201503a by the KMTNet Supernova Program

NASA Astrophysics Data System (ADS)

Brown, Shannon; Moon, Dae-Sik; Ni, Yuan Qi; Drout, Maria; Antoniadis, John; Afsariardchi, Niloufar; Cha, Sang-Mok; Lee, Yongseok

2018-06-01

We report multicolor BVI monitoring and spectroscopic classification of the dwarf nova KSP-OT-201503a. The transient was detected by the Korean Microlensing Telescope Network (KMTNet) Supernova Program (KSP) in 2015 March, reached a peak apparent magnitude V ≃ 17.3 mag from a quiescent magnitude V ≃ 22.6 mag, and lasted for approximately 17 days. Our high-cadence sampling allows us to identify distinctive phases consisting of a rapid ascent, a main outburst composed of a flat plateau followed by a gradual dimming, and a quick decline. We observe the sharp transition between the ascent phase and main outburst phase, likely related to the deceleration of the heating front as it passes through the accretion disk. These features in the light curves indicate that the outburst is outside-in. Archival data reveal the outburst history of the source, showing at least three outbursts between 2011 and 2015. These are equally separated by approximately 25 months, though we find a recurrence time as short as 189 days is compatible with the archival data. An optical spectrum obtained 701 days from outburst peak shows prominent Balmer emission lines superimposed on a blue continuum, consistent with a cataclysmic variable in quiescence. The outburst properties of KSP-OT-201503a closely resemble those of U Gem-type dwarf novae usually associated with younger, longer-period systems above the period gap of 2–3 hr observed in cataclysmic variables. This suggests that the source may be a rare U Gem-type dwarf nova with a long recurrence time, though we are unable to rule out the possibility that KSP-OT-201503a lies below the period gap.

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

PubMed

Godon, Patrick; Sion, Edward M; Starrfield, Sumner; Livio, Mario; Williams, Robert E; Woodward, Charles E; Kuin, Paul; Page, Kim L

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chomiuk, Laura; Nelson, Thomas; Mukai, Koji

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 themore » 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.« less

Detection of the supercycle in V4140 Sagittarii: First eclipsing ER Ursae Majoris-like object

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Cook, Lewis M.

2018-05-01

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination, and there is no need to introduce mass transfer bursts from its donor star.

Detection of the supercycle in V4140 Sagittarii: First eclipsing ER Ursae Majoris-like object

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Cook, Lewis M.

2018-06-01

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination, and there is no need to introduce mass transfer bursts from its donor star.

49 CFR 236.723 - Circuit, double wire; line.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, double wire; line. 236.723 Section 236... § 236.723 Circuit, double wire; line. An electric circuit not employing a common return wire; a circuit formed by individual wires throughout. ...

49 CFR 236.723 - Circuit, double wire; line.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, double wire; line. 236.723 Section 236... § 236.723 Circuit, double wire; line. An electric circuit not employing a common return wire; a circuit formed by individual wires throughout. ...

X-ray Observations of the Bright Old Nova V603 Aquilae

NASA Technical Reports Server (NTRS)

Mukai, K.; Orio, M.

2004-01-01

We report on our Chandra and RXTE observations of the bright old nova, V603 Aql, performed in 2001 April, supplemented by our analysis of archival X-ray data on this object. We find that the RXTE data are contaminated by the Galactic Ridge X-ray emission. After accounting for this effect, we find a high level of aperiodic variability in the RXTE data, at a level consistent with the uncontaminated Chandra data. The Chandra HETG spectrum clearly originates in a multi-temperature plasma. We constrain the possible emission measure distribution of the plasma through a combination of global and local fits. The X-ray luminosity and the spectral shape of V603 Aql resemble those of SS Cyg in transition between quiescence and outburst. The fact that the X-ray flux variability is only weakly energy dependent can be interpreted by supposing that the variability is due to changes in the maximum temperature of the plasma. The plasma density is likely to be high, and the emission region is likely to be compact. Finally, the apparent overabundance of Ne is consistent with V603 Aql being a young system.

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.

Comparative scanning electron microscope analysis of diode laser and desensitizing toothpastes for evaluation of efficacy of dentinal tubular occlusion

PubMed Central

Reddy, Guntakala Vikram; Akula, Sushma; Malgikar, Suryakanth; Babu, Palaparthy Raja; Reddy, Gooty Jagadish; Josephin, Johnson Juliet

2017-01-01

Background: The present study aims to evaluate the efficacy of diode laser alone and in combination with desensitizing toothpastes in occluding dentinal tubules (both partially occluded and completely occluded tubules) by scanning electron microscope (SEM). Materials and Methods: Fifty human teeth were extracted, cervical cavities were prepared and etched with 17% ethylenediaminetetraacetic acid, and smear layer was removed to expose the tubules. The teeth were divided into five groups: Group I – Application of NovaMin-formulated toothpaste, Group II – Application of Pro-Argin™-formulated toothpaste, Group III – Application of diode laser in noncontact mode, Group IV – NovaMin-formulated toothpaste followed by laser irradiation, and Group V – Pro-Argin™-formulated toothpaste followed by laser irradiation. After treatment, quantitative analysis of occluded dentinal tubules was done by SEM analysis. Results: The mean values of percentages of total occlusion of dentinal tubules in Groups I, II, III, IV, and V were 92.73% ± 1.38, 90.67% ± 1.86, 96.57% ± 0.64, 97.3% ± 0.68, and 96.9% ± 6.08, respectively. Addition of diode laser (Groups III, IV, and V) yielded a significant occlusion of the dentinal tubules when compared to desensitizing toothpastes alone (Groups I and II). Conclusion: Diode laser (Group III) has shown more efficacy in occluding dentinal tubules when compared with desensitizing toothpastes which was statistically significant (P < 0.05). Among the five groups, NovaMin + diode laser (Group IV) showed the highest percentage of occluded dentinal tubules. PMID:29398853

First measurement of muon-neutrino disappearance in NOvA

NASA Astrophysics Data System (ADS)

Adamson, P.; Ader, C.; Andrews, M.; Anfimov, N.; Anghel, I.; Arms, K.; Arrieta-Diaz, E.; Aurisano, A.; Ayres, D. S.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Bernstein, R.; Betancourt, M.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Biery, K.; Blackburn, T.; Bocean, V.; Bogert, D.; Bolshakova, A.; Bowden, M.; Bower, C.; Broemmelsiek, D.; Bromberg, C.; Brunetti, G.; Bu, X.; Butkevich, A.; Capista, D.; Catano-Mur, E.; Chase, T. R.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cronin-Hennessy, D.; Cunningham, A.; Davies, G. S.; Davies, J. P.; Del Tutto, M.; Derwent, P. F.; Deepthi, K. N.; Demuth, D.; Desai, S.; Deuerling, G.; Devan, A.; Dey, J.; Dharmapalan, R.; Ding, P.; Dixon, S.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Ehrlich, R.; Feldman, G. J.; Felt, N.; Fenyves, E. J.; Flumerfelt, E.; Foulkes, S.; Frank, M. J.; Freeman, W.; Gabrielyan, M.; Gallagher, H. R.; Gebhard, M.; Ghosh, T.; Gilbert, W.; Giri, A.; Goadhouse, S.; Gomes, R. A.; Goodenough, L.; Goodman, M. C.; Grichine, V.; Grossman, N.; Group, R.; Grudzinski, J.; Guarino, V.; Guo, B.; Habig, A.; Handler, T.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Howcroft, C.; Huang, J.; Huang, X.; Hylen, J.; Ishitsuka, M.; Jediny, F.; Jensen, C.; Jensen, D.; Johnson, C.; Jostlein, H.; Kafka, G. K.; Kamyshkov, Y.; Kasahara, S. M. S.; Kasetti, S.; Kephart, K.; Koizumi, G.; Kotelnikov, S.; Kourbanis, I.; Krahn, Z.; Kravtsov, V.; Kreymer, A.; Kulenberg, Ch.; Kumar, A.; Kutnink, T.; Kwarciancy, R.; Kwong, J.; Lang, K.; Lee, A.; Lee, W. M.; Lee, K.; Lein, S.; Liu, J.; Lokajicek, M.; Lozier, J.; Lu, Q.; Lucas, P.; Luchuk, S.; Lukens, P.; Lukhanin, G.; Magill, S.; Maan, K.; Mann, W. A.; Marshak, M. L.; Martens, M.; Martincik, J.; Mason, P.; Matera, K.; Mathis, M.; Matveev, V.; Mayer, N.; McCluskey, E.; Mehdiyev, R.; Merritt, H.; Messier, M. D.; Meyer, H.; Miao, T.; Michael, D.; Mikheyev, S. P.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Musser, J.; Newman, H. B.; Nelson, J. K.; Niner, E.; Norman, A.; Nowak, J.; Oksuzian, Y.; Olshevskiy, A.; Oliver, J.; Olson, T.; Paley, J.; Pandey, P.; Para, A.; Patterson, R. B.; Pawloski, G.; Pearson, N.; Perevalov, D.; Pershey, D.; Peterson, E.; Petti, R.; Phan-Budd, S.; Piccoli, L.; Pla-Dalmau, A.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Psihas, F.; Pushka, D.; Qiu, X.; Raddatz, N.; Radovic, A.; Rameika, R. A.; Ray, R.; Rebel, B.; Rechenmacher, R.; Reed, B.; Reilly, R.; Rocco, D.; Rodkin, D.; Ruddick, K.; Rusack, R.; Ryabov, V.; Sachdev, K.; Sahijpal, S.; Sahoo, H.; Samoylov, O.; Sanchez, M. C.; Saoulidou, N.; Schlabach, P.; Schneps, J.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sherwood, B.; Sheshukov, A.; Singh, J.; Singh, V.; Smith, A.; Smith, D.; Smolik, J.; Solomey, N.; Sotnikov, A.; Sousa, A.; Soustruznik, K.; Stenkin, Y.; Strait, M.; Suter, L.; Talaga, R. L.; Tamsett, M. C.; Tariq, S.; Tas, P.; Tesarek, R. J.; Thayyullathil, R. B.; Thomsen, K.; Tian, X.; Tognini, S. C.; Toner, R.; Trevor, J.; Tzanakos, G.; Urheim, J.; Vahle, P.; Valerio, L.; Vinton, L.; Vrba, T.; Waldron, A. V.; Wang, B.; Wang, Z.; Weber, A.; Wehmann, A.; Whittington, D.; Wilcer, N.; Wildberger, R.; Wildman, D.; Williams, K.; Wojcicki, S. G.; Wood, K.; Xiao, M.; Xin, T.; Yadav, N.; Yang, S.; Zadorozhnyy, S.; Zalesak, J.; Zamorano, B.; Zhao, A.; Zirnstein, J.; Zwaska, R.; NOvA Collaboration

2016-03-01

This paper reports the first measurement using the NOvA detectors of νμ disappearance in a νμ beam. The analysis uses a 14 kton-equivalent exposure of 2.74 ×1020 protons-on-target from the Fermilab NuMI beam. Assuming the normal neutrino mass hierarchy, we measure Δ m322=(2.52-0.18+0.20)×10-3 eV2 and sin2θ23 in the range 0.38-0.65, both at the 68% confidence level, with two statistically degenerate best-fit points at sin2θ23=0.43 and 0.60. Results for the inverted mass hierarchy are also presented.

NLTE Model Atmospheres for Super-Soft X-ray Sources

NASA Astrophysics Data System (ADS)

Rauch, Thomas; Werner, Klaus

2009-09-01

Spectral analysis by means of fully line-blanketed Non-LTE model atmospheres has arrived at a high level of sophistication. The Tübingen NLTE Model Atmosphere Package (TMAP) is used to calculate plane-parallel NLTE model atmospheres which are in radiative and hydrostatic equilibrium. Although TMAP is not especially designed for the calculation of burst spectra of novae, spectral energy distributions (SEDs) calculated from TMAP models are well suited e.g. for abundance determinations of Super Soft X-ray Sources like nova V4743 Sgr or line identifications in observations of neutron stars with low magnetic fields in low-mass X-ray binaries (LMXBs) like EXO 0748-676.

Nonmaximal θ23 Mixing at NOvA from Neutrino Decoherence

NASA Astrophysics Data System (ADS)

Coelho, João A. B.; Mann, W. Anthony; Bashar, Saqib S.

2017-06-01

In a study of a muon-neutrino disappearance at 810 km, the NOvA experiment finds flavor mixing of the atmospheric sector to deviate from maximal (sin2θ23=0.5 ) by 2.6 σ . The result is in tension with the 295-km baseline measurements of T2K, which are consistent with maximal mixing. We propose that θ23 is in fact maximal, and that the disagreement is a harbinger of environmentally induced decoherence. The departure from maximal mixing can be accounted for by an energy-independent decoherence of strength Γ =(2.3 ±1.1 )×10-23 GeV .

Andromeda

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

(abbrev. And, gen. Andromedae; area 722 sq. deg.) A northern constellation that lies between Perseus and Pegasus, and culminates at midnight in early October. It is named after the daughter of King Cepheus and Queen Cassiopeia in Greek mythology, who was rescued by Perseus from being sacrificed to the sea monster Cetus, and is usually shown on early celestial charts as a chained maiden. Its brigh...

A BRITE view on δ Scuti and γ Doradus stars

NASA Astrophysics Data System (ADS)

Zwintz, K.

2017-09-01

BRITE-Constellation has obtained data for a few δ; Scuti and γ Doradus type stars. A short overview of the pulsational content found in five stars - β Cassiopeiae, ɛ Cephei, M Velorum, β Pictoris and QW Puppis - is given and the potential of BRITE-Constellation observations of δ Scuti and γ Doradus pulsators is discussed.

28 CFR 42.723 - Compliance information.

Code of Federal Regulations, 2013 CFR

2013-07-01

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32 CFR 723.10 - Settlement of claims.

Code of Federal Regulations, 2011 CFR

2011-07-01

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32 CFR 723.6 - Action by the Board.

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2012-07-01

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2010-07-01

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25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2011 CFR

2011-04-01

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25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

32 CFR 723.6 - Action by the Board.

Code of Federal Regulations, 2013 CFR

2013-07-01

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25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 2 2014-04-01 2014-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 2 2013-04-01 2013-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 2 2012-04-01 2012-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

32 CFR 700.723 - Administration and discipline: Separate and detached command.

Code of Federal Regulations, 2010 CFR

2010-07-01

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32 CFR 700.723 - Administration and discipline: Separate and detached command.

Code of Federal Regulations, 2014 CFR

2014-07-01

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32 CFR 700.723 - Administration and discipline: Separate and detached command.

Code of Federal Regulations, 2011 CFR

2011-07-01

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32 CFR 700.723 - Administration and discipline: Separate and detached command.

Code of Federal Regulations, 2013 CFR

2013-07-01

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32 CFR 700.723 - Administration and discipline: Separate and detached command.

Code of Federal Regulations, 2012 CFR

2012-07-01

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40 CFR 35.723 - Competitive process.

Code of Federal Regulations, 2010 CFR

2010-07-01

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47 CFR 90.723 - Selection and assignment of frequencies.

Code of Federal Regulations, 2011 CFR

2011-10-01

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2011-07-01

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2012-07-01

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2014-07-01

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31 CFR 501.723 - Prehearing disclosures; methods to discover additional matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... discover additional matter. 501.723 Section 501.723 Money and Finance: Treasury Regulations Relating to... disclosures; methods to discover additional matter. (a) Initial disclosures. (1) Except to the extent... the respondent); (ii) The legal theories upon which it will rely; (iii) Copies and a list of documents...

21 CFR 172.723 - Epoxidized soybean oil.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Epoxidized soybean oil. 172.723 Section 172.723 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN...

21 CFR 172.723 - Epoxidized soybean oil.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Epoxidized soybean oil. 172.723 Section 172.723 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN...

Identificação de variáveis cataclísmicas eruptivas na direção do bojo galáctico e Nuvens de Magalhães usando dados do OGLE

NASA Astrophysics Data System (ADS)

Cieslinski, D.; Diaz, M. P.; Mennickent, R.; Pietrzyski, G.

2003-08-01

Na década de 90 iniciaram-se vários programas para a pesquisa de matéria escura na Galáxia usando o efeito de microlentes gravitacionais. Entre os projetos mais bem conhecidos podemos mencionar o OGLE (Optical Gravitational Lensing Experiment) e o MACHO (MAssive Compact Halo Objects). A estratégia usada por eles consiste em fazer fotometria de banda larga (normalmente B, R e I) de um grande número de estrelas (dezenas de milhões) tão freqüentemente quanto possí vel e por longos perí odos de tempo (anos). Uma tal sistemática de observação, além de descobrir inúmeras lentes gravitacionais, é também muito apropriada para a descoberta de estrelas variáveis. De fato, inúmeras novas variáveis de vários tipos foram descobertas como subproduto. Exemplos podem ser encontrados nos endereços http://bulge.princeton.edu/~ogle/ e http://wwwmacho.mcmaster.ca/. As variáveis cataclí smicas eruptivas (novas clássicas, novas recorrentes e novas anãs) são objetos que apresentam variabilidade de grande amplitude com escalas de tempo de dias a centenas de dias e, por esta razão, devem ter sido detectadas em grande número nestes "surveys". Para testar esta possibilidade nós procuramos nos dados do OGLE por tais sistemas e o presente trabalho mostra os resultados desta pesquisa. Os objetos foram selecionados entre as variáveis detectadas usando a amplitude de variação de brilho como critério principal. Este critério forneceu 13756 objetos, sendo 2169 na direção da Grande Nuvem de Magalhães, 1162 na direção da Pequena Nuvem de Magalhães e o restante na direção do Bojo Galáctico. A análise foi feita inspecionando-se visualmente cada curva de luz por erupções com as características acima mencionadas. Os resultados obtidos podem ser sumarizados como: descoberta de duas novas clássicas e 33 novas anãs. Além disso, pode-se mencionar a identificação de candidatas a outros tipos de variáveis como: estrelas simbióticas, RV Tauri, R Coronae Borealis, Miras, etc.

21 CFR 522.723 - Diprenorphine hydrochloride injection.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Diprenorphine hydrochloride injection. 522.723 Section 522.723 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... use in wild or exotic animals only. Do not use in domestic food-producing animals. Do not use 30 days...

7 CFR 58.723 - Basis for selecting cheese for processing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Basis for selecting cheese for processing. 58.723... Service 1 Operations and Operating Procedures § 58.723 Basis for selecting cheese for processing. A... vat of cheese shall have been examined to determine the suitability of the vat for use in process...

7 CFR 58.723 - Basis for selecting cheese for processing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Basis for selecting cheese for processing. 58.723... Service 1 Operations and Operating Procedures § 58.723 Basis for selecting cheese for processing. A... vat of cheese shall have been examined to determine the suitability of the vat for use in process...

Characterizing the Exhaust Plume of the Three-Electrode Micro Pulsed Plasma Thrusters

DTIC Science & Technology

2009-03-01

Plasma Thruster “, J Prop Power 1998;14:716-35 3 W. Andrew Hoskins, Christopher Rayburn, and Charles Sarmiento ” Pulsed Plasma Thruster...plasma thrusters are based on the previous PPT-4 and PPT-7 thruster designs. These thrusters used energy levels between 40 and 80 J generating several...PPT Programs 3 Program Year Energy Voltage Program Year Energy Voltage Zond-2 1964 50 J 1000 V TIP-III 1976 20 J 1630 V LES-6 1968 1.85 J 1360 V NOVA

Asynchronous polar V1500 Cyg: orbital, spin and beat periods

NASA Astrophysics Data System (ADS)

Pavlenko, E. P.; Mason, P. A.; Sosnovskij, A. A.; Shugarov, S. Yu; Babina, Ju V.; Antonyuk, K. A.; Andreev, M. V.; Pit, N. V.; Antonyuk, O. I.; Baklanov, A. V.

2018-06-01

The bright Nova Cygni 1975 is a rare nova on a magnetic white dwarf (WD). Later it was found to be an asynchronous polar, now called V1500 Cyg. Our multisite photometric campaign occurring 40 years post eruption covered 26-nights (2015-2017). The reflection effect from the heated donor has decreased, but still dominates the optical radiation with an amplitude ˜1m.5. The 0m.3 residual reveals cyclotron emission and ellipsoidal variations. Mean brightness modulation from night-to-night is used to measure the 9.6-d spin-orbit beat period that is due to changing accretion geometry including magnetic pole-switching of the flow. By subtracting the orbital and beat frequencies, spin-phase dependent light curves are obtained. The amplitude and profile of the WD spin light curves track the cyclotron emitting accretion regions on the WD and they vary systematically with beat phase. A weak intermittent signal at 0.137613-d is likely the spin period, which is 1.73(1) min shorter than the orbital period. The O-C diagram of light curve maxima displays phase jumps every one-half beat period, a characteristic of asynchronous polars. The first jump we interpret as pole switching between regions separated by 180°. Then the spot drifts during ˜ 0.1 beat phase before undergoing a second phase jump between spots separated by less than 180°. We trace the cooling of the still hot WD as revealed by the irradiated companion. The post nova evolution and spin-orbit asynchronism of V1500 Cyg continues to be a powerful laboratory for accretion flows onto magnetic white dwarfs.

Infant-mortality testing of high-energy-density capacitors used on Nova

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merritt, B.T.; Whitham, K.

1983-01-01

Nova is a solid-state large laser for inertial-confinement fusion research. Its flashlamps are driven by a 60-MJ capacitor bank. Part of this bank is being built with high-energy-density capacitors, 52-..mu..F, 22 kV, 12.5 kJ. A total of 2645 of these capacitors have been purchased from two manufacturers. Each capacitor was infant-mortality tested. The first test consisted of a high-potential test, bushing-to-case, since these capacitors have dual bushings. Then the capacitors were discharged 500 times with circuit conditions approximating the capacitors normal flashlamp load. Failure of either of these tests or if the capacitor was leaking was cause for rejection.

Early Program Development

NASA Image and Video Library

1962-04-01

In this 1962 artist's concept , a proposed Nova rocket, shown at right, is compared to a Saturn C-1, left, and a Saturn C-5, center. The Marshall Space Flight Center directed studies of Nova configuration from 1960 to 1962 as a means of achieving a marned lunar landing with a direct flight to the Moon. Various configurations of the vehicle were examined, the largest being a five-stage vehicle using eight F-1 engines in the first stage. Although the program was effectively cancelled in 1962 when NASA planners selected the lunar-orbital rendezvous mode, the proposed F-1 engine was eventually used to propel the first stage of the Saturn V launch vehicle in the Apollo Program.

A Broad 22 Micron Emission Feature in the Carina Nebula H ii Region.

PubMed

Chan; Onaka

2000-04-10

We report the detection of a broad 22 µm emission feature in the Carina Nebula H ii region by the Infrared Space Observatory (ISO) short-wavelength spectrometer. The feature shape is similar to that of the 22 µm emission feature of newly synthesized dust observed in the Cassiopeia A supernova remnant. This finding suggests that both of the features are arising from the same carrier and that supernovae are probably the dominant production sources of this new interstellar grain. A similar broad emission dust feature is also found in the spectra of two starburst galaxies from the ISO archival data. This new dust grain could be an abundant component of interstellar grains and can be used to trace the supernova rate or star formation rate in external galaxies. The existence of the broad 22 µm emission feature complicates the dust model for starburst galaxies and must be taken into account correctly in the derivation of dust color temperature. Mg protosilicate has been suggested as the carrier of the 22 µm emission dust feature observed in Cassiopeia A. The present results provide useful information in studies on the chemical composition and emission mechanism of the carrier.

King Charles' Star: A Multidisciplinary Approach to Dating the Supernova Known as Cassiopeia A

NASA Astrophysics Data System (ADS)

Lunn, M.

2012-06-01

(Abstract only) Few astronomical phenomena have been as studied as the supernova known as Cassiopeia A. Widely believed to have occurred in the latter half of the seventeenth century, it is also thought to have gone unrecorded. This paper will argue that Cas A did not go unobserved, but in fact was seen in Britain on May 29, 1630, and coincided with the birth of the future King Charles II of Great Britain. This "noon-day star" is an important feature of Stuart/Restoration propaganda, the significance of which has been widely acknowledged by historians and literary experts. The argument here, however, is that in addition the historical accounts provide credible evidence for a genuine astronomical event, the nature of which must be explained. Combining documentary analysis with an overview of the current scientific thinking on dating supernovae, the authors put forward their case for why Charles' star should be recognized as a sighting of Cas A. Finally, it will be argued that a collaborative approach between the humanities and the sciences can be a valuable tool, not just in furthering our understanding of Cas A, but in the dating of supernovae in general.

King Charles` Star: A Multidisciplinary Approach To Dating The Supernova Known As Cassiopeia A

NASA Astrophysics Data System (ADS)

Lunn, Martin; Rakoczy, L.

2011-01-01

Few astronomical phenomena have been as studied as the supernova known as Cassiopeia A. Widely believed to have occurred in the latter half of the seventeenth century, it is also thought to have gone unrecorded. This paper will argue that Cas A did not go unobserved, but in fact was seen in Britain on May 29, 1630, and coincided with the birth of the future King Charles II of Great Britain. This `noon-day star’ is an important feature of Stuart/Restoration propaganda, the significance of which has been widely acknowledged by historians and literary experts. The argument here, however, is that in addition the historical accounts provide credible evidence for a genuine astronomical event, the nature of which must be explained. Combining documentary analysis with an overview of the current scientific thinking on dating supernova, the authors put forward their case for why Charles’ star should be recognized as a sighting of Cas A. Finally, it will be argued that a collaborative approach between the humanities and the sciences can be a valuable tool, not just in furthering our understanding of Cas A, but in the dating of supernovae in general.

King Charles` Star: A Multidisciplinary Approach to Dating the Supernova Known as Cassiopeia A

NASA Astrophysics Data System (ADS)

Lunn, Martin

2011-05-01

Few astronomical phenomena have been as studied as the supernova known as Cassiopeia A. Widely believed to have occurred in the latter half of the seventeenth century, it is also thought to have gone unrecorded. This paper will argue that Cas A did not go unobserved, but in fact was seen in Britain on May 29, 1630, and coincided with the birth of the future King Charles II of Great Britain. This 'noon-day star' is an important feature of Stuart/Restoration propaganda, the significance of which has been widely acknowledged by historians and literary experts. The argument here, however, is that in addition the historical accounts provide credible evidence for a genuine astronomical event, the nature of which must be explained. Combining documentary analysis with an overview of the current scientific thinking on dating supernova, the authors put forward their case for why Charles' star should be recognized as a sighting of Cas A. Finally, it will be argued that a collaborative approach between the humanities and the sciences can be a valuable tool, not just in furthering our understanding of Cas A, but in the dating of supernovae in general.

The Circumstellar Medium of Cassiopeia A Inferred from the Outer Ejecta Knot Properties

NASA Technical Reports Server (NTRS)

Hwang, Una; Laming, J. Martin

2009-01-01

We investigate the effect of the circumstellar medium density profile on the X-ray emission from outer ejecta knots in the Cassiopeia A supernova remnant using the 1 Ms Chandra observation. The spectra of a number of radial series of ejecta knots at various positions around the remnant are analyzed using techniques similar to those devised in previous papers. We can obtain a reasonable match to our data for a circumstellar density profile proportional to r(sup -2) as would arise from the steady dense wind of a red supergiant, but the agreement is improved if we introduce a central cavity around the progenitor into our models. Such a profile might arise if the progenitor emitted a, fast tenuous stellar wind for a short period immediately prior to explosion. We review other lines of evidence supporting this conclusion. The spectra also indicate the widespread presence of Fe-enriched plasma that was presumably formed by complete Si burning during the explosion, possibly via alpha-rich freezeout. This component is typically associated with hotter and more highly ionized gas than the bulk of the O- and Si-rich ejecta.

A Critical Assessment of Cyclic Softening and Hardening Behavior in a Near- α Titanium Alloy During Thermomechanical Fatigue

NASA Astrophysics Data System (ADS)

Prasad, Kartik; Sarkar, Rajdeep; Rao, K. Bhanu Sankara; Sundararaman, M.

2016-10-01

Thermomechanical fatigue behavior of Ti-alloy Timetal 834 has been studied at two temperature intervals viz. 573 K to 723 K (300 °C to 450 °C) and 723 K to 873 K (450 °C to 600 °C) under mechanical strain-controlled cycling. Among the temperatures studied, the alloy exhibited initial cyclic softening followed by cyclic hardening at 723 K (450 °C) in the temperature interval of 573 K to 723 K (300 °C to 450 °C). However, continuous cyclic hardening was observed at 723 K (450 °C) in 723 K to 873 K (450 °C to 600 °C). At 573 K (300 °C) and 873 K (600 °C), cyclic softening was observed in the cyclic stress response curves in both the temperature intervals. The dislocation substructure was observed to be planar in both the modes of TMF loading. Based on TEM microstructures and few unconventional fatigue tests, the observed cyclic hardening is attributed to dynamic strain aging. The reduced fatigue life at 723 K to 873 K (450 °C to 600 °C) under OP-TMF loading was attributed to the combined effect of cyclic hardening (leading to early strain localization and crack initiation), oxidation, and development of tensile mean stresses.

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

PubMed

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

2016-05-25

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.

27 CFR 7.23 - Brand names.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Brand names. 7.23 Section... Beverages § 7.23 Brand names. (a) General. The product shall bear a brand name, except that if not sold under a brand name, then the name of the person required to appear on the brand label shall be deemed a...

27 CFR 19.723 - Effect of redistillation on plant size and bond amount.

Code of Federal Regulations, 2012 CFR

2012-04-01

... amount. The redistillation of spirits at an alcohol fuel plant may affect the alcohol fuel plant size... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Effect of redistillation on plant size and bond amount. 19.723 Section 19.723 Alcohol, Tobacco Products and Firearms ALCOHOL...

27 CFR 19.723 - Effect of redistillation on plant size and bond amount.

Code of Federal Regulations, 2013 CFR

2013-04-01

... amount. The redistillation of spirits at an alcohol fuel plant may affect the alcohol fuel plant size... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Effect of redistillation on plant size and bond amount. 19.723 Section 19.723 Alcohol, Tobacco Products and Firearms ALCOHOL...

27 CFR 19.723 - Effect of redistillation on plant size and bond amount.

Code of Federal Regulations, 2011 CFR

2011-04-01

... amount. The redistillation of spirits at an alcohol fuel plant may affect the alcohol fuel plant size... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Effect of redistillation on plant size and bond amount. 19.723 Section 19.723 Alcohol, Tobacco Products and Firearms ALCOHOL...

27 CFR 19.723 - Effect of redistillation on plant size and bond amount.

Code of Federal Regulations, 2014 CFR

2014-04-01

... amount. The redistillation of spirits at an alcohol fuel plant may affect the alcohol fuel plant size... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Effect of redistillation on plant size and bond amount. 19.723 Section 19.723 Alcohol, Tobacco Products and Firearms ALCOHOL...

12 CFR 218.723 - Exemptions for special accounts, transferred accounts, foreign branches and a de minimis number...

Code of Federal Regulations, 2010 CFR

2010-01-01

... accounts, foreign branches and a de minimis number of accounts. 218.723 Section 218.723 Banks and Banking... accounts, transferred accounts, foreign branches and a de minimis number of accounts. (a) Short-term... dealer. (e) De minimis exclusion. A bank may, in determining its compliance with the chiefly compensated...

12 CFR 218.723 - Exemptions for special accounts, transferred accounts, foreign branches and a de minimis number...

Code of Federal Regulations, 2011 CFR

2011-01-01

... accounts, foreign branches and a de minimis number of accounts. 218.723 Section 218.723 Banks and Banking... accounts, transferred accounts, foreign branches and a de minimis number of accounts. (a) Short-term... dealer. (e) De minimis exclusion. A bank may, in determining its compliance with the chiefly compensated...

Polymorphism of prion protein gene in Arctic fox (Vulpes lagopus).

PubMed

Wan, Jiayu; Bai, Xue; Liu, Wensen; Xu, Jing; Xu, Ming; Gao, Hongwei

2009-07-01

Prion diseases are fatal neurodegenerative disorders of humans and certain other mammals. Prion protein gene (Prnp) is associated with susceptibility and species barrier to prion diseases. No natural and experimental prion diseases have been documented to date in Arctic fox. In the present study, coding region of Prnp from 135 Arctic foxes were cloned and screened for polymorphisms. Our results indicated that the Arctic fox Prnp open reading frame (ORF) contains 771 nucleotides encoding 257 amino acids. Four single nucleotide polymorphisms (SNPs) (G312C, A337G, C541T, and A723G) were identified. SNPs G312C and A723G produced silent mutations, but SNPs A337G and C541T resulted in a M-V change at codon 113 and R-C at codon 181, respectively. The Arctic fox Prnp amino acid sequence was similar to that of the dog (XM 542906). In short, this study provides preliminary information about genotypes of Prnp in Arctic fox.

Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

NASA Astrophysics Data System (ADS)

Adamson, P.; Aliaga, L.; Ambrose, D.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Augsten, K.; Aurisano, A.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blackburn, T.; Bolshakova, A.; Bromberg, C.; Brown, J.; Brunetti, G.; Buchanan, N.; Butkevich, A.; Bychkov, V.; Campbell, M.; Catano-Mur, E.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G. S.; Davies, J. P.; Derwent, P. F.; Dharmapalan, R.; Ding, P.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G. J.; Frank, M. J.; Gabrielyan, M.; Gallagher, H. R.; Germani, S.; Ghosh, T.; Giri, A.; Gomes, R. A.; Goodman, M. C.; Grichine, V.; Groh, M.; Group, R.; Grover, D.; Guo, B.; Habig, A.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Howard, B.; Hylen, J.; Jediny, F.; Judah, M.; Kafka, G. K.; Kalra, D.; Kasahara, S. M. S.; Kasetti, S.; Keloth, R.; Kolupaeva, L.; Kotelnikov, S.; Kourbanis, I.; Kreymer, A.; Kumar, A.; Kurbanov, S.; Lackey, T.; Lang, K.; Lee, W. M.; Lin, S.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W. A.; Marshak, M. L.; Matera, K.; Matveev, V.; Méndez, D. P.; Messier, M. D.; Meyer, H.; Miao, T.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Murphy, R.; Musser, J.; Nelson, J. K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Patterson, R. B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Phan-Budd, S.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Principato, C.; Psihas, F.; Radovic, A.; Rameika, R. A.; Rebel, B.; Reed, B.; Rocco, D.; Rojas, P.; Ryabov, V.; Sachdev, K.; Sail, P.; Samoylov, O.; Sanchez, M. C.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sheshukov, A.; Singh, J.; Singh, J.; Singh, P.; Singh, V.; Smolik, J.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R. L.; Tas, P.; Thayyullathil, R. B.; Thomas, J.; Tian, X.; Tognini, S. C.; Tripathi, J.; Tsaris, A.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vold, A.; Vrba, T.; Wang, B.; Wetstein, M.; Whittington, D.; Wojcicki, S. G.; Wolcott, J.; Yadav, N.; Yang, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.; NOvA Collaboration

2017-10-01

We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05 ×1020 protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 ±9.7 (stat ) ±9.4 (syst ) events predicted assuming mixing only occurs between active neutrino species. No evidence for νμ→νs transitions is found. Interpreting these results within a 3 +1 model, we place constraints on the mixing angles θ24<20.8 ° and θ34<31.2 ° at the 90% C.L. for 0.05 eV2≤Δ m412≤0.5 eV2 , the range of mass splittings that produce no significant oscillations over the Near Detector baseline.

All-sky monitor observations of the decay of A0620-00 (Nova monocerotis 1975)

NASA Technical Reports Server (NTRS)

Kaluzienski, L. J.; Holt, S. S.; Boldt, E. A.; Serlemitsos, P. J.

1976-01-01

The All-Sky X-ray Monitor onboard Ariel 5 has observed the 3-6 keV decline of the bright transient X-ray source A0620-00 on a virtually continuous basis during the period September 1975 - March 1976. The source behavior on timescales 100 minutes is characterized by smooth, exponential decays interrupted by substantial increases in October and February. The latter increase was an order-of-magnitude rise above the extrapolated exponential fall-off, and was followed by a final rapid decline. Upper limits of 2.5% and 10% were found for any periodicities in the range 0d.2 - 10d during the early and later decay phases, respectively. A probable correlation between the optical and 3-6 keV emission from A0620-00 was noted, effectively ruling out models involving traditional optical novae in favor of Roche-lobe overflow in a binary system. The existing data on the transient X-ray sources is consistent with two distinct luminosity-lifetime classes of these objects.

Inflammatory biomarkers, disease activity index, and self-reported disability may be predictors of chronic arthritis after chikungunya infection: brief report.

PubMed

Sepúlveda-Delgado, J; Vera-Lastra, O L; Trujillo-Murillo, K; Canseco-Ávila, L M; Sánchez-González, R A; Gómez-Cruz, O; Lugo-Trampe, A; Fernández-Salas, I; Danis-Lozano, R; Contreras-Contreras, A; Mendoza-Torres, A; Domínguez-Arrevillaga, S; Mena-Vela, B A; Ocaña-Sibilla, M; Ramirez-Valdespino, J C; Jara, L J

2017-03-01

The chikungunya virus (ChikV) is a reemerging mosquito-borne pathogen that causes disabling chronic arthritis. The relationship between clinical evolution and inflammatory biomarkers in patients with ChikV-induced arthritis has not been fully described. We performed a prospective case series to evaluate the association among joint involvement, self-reported disability, and inflammatory biomarkers. Patients with ChikV infection were followed for 1 year. Joint involvement and self-reported disability were evaluated with disease activity index 28 (DAS-28) and World Health Organization Disablement Assessment Schedule II (WHODAS-II). Interleukin-6 (IL-6), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were used as biomarkers. Ten patients with mean age 48 ±15.04 years were included. Symptoms at diagnosis were fever, arthralgias, myalgias, rash, arthritis, nausea, vomiting, and back pain. Polyarticular involvement was present in seven cases. At diagnosis, measures were as follows: DAS-28, 5.08±1.11; WHODAS-II score, 72.3±10.3 %; CRP, 5.09±7.23 mg/dL; ESR, 33.5±17.5 mm/h; RF, 64±21.7 IU/mL; and IL-6, 17.6±10.3 pg/mL. Six patients developed subacute and chronic symptoms. During follow-up, DAS-28 index, WHODAS-II score, ESR, and IL-6 were statistically different in patients with subacute and chronic symptoms compared to those who resolved in the acute phase (p < 0.05). DAS-28 index, WHODAS-II score, and IL-6 were related to chronicity of articular symptoms and could be used as predictors of ChikV-induced arthritis.

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

Spitzer Observations of the New Luminous Red Nova M85 OT2006-1

NASA Astrophysics Data System (ADS)

Rau, A.; Kulkarni, S. R.; Ofek, E. O.; Yan, L.

2007-04-01

M85 OT2006-1 is the latest and most brilliant addition to the small group of known luminous red novae (LRNe). An identifying characteristic of the previously detected events (M31 RV, V4332 Sgr, and V838 Mon) was a spectral redward evolution connected with an emerging infrared component following the optical decay. Here we report on the discovery of a similar feature in Keck NIRC and Spitzer photometry of M85 OT2006-1 6 months posteruption. We find that its 2.1-22 μm spectral energy distribution is best described by a blackbody with effective temperature Teff=950+/-150 K and bolometric luminosity L=2.9+0.4-0.5×105 Lsolar. Assuming spherical geometry, the blackbody effective radius, R=2.0+0.6-0.4×104 Rsolar, and corresponding expansion velocity, v=870+260-180 km s-1, are remarkably similar to the properties of M31 RV 70 days after its eruption. Furthermore, we propose a search strategy for LRNe in the local universe making use of the longevity of their infrared excess emission and discuss the expected number of events in the Spitzer Infrared Nearby Galaxies Survey.

FUSE SPECTROSCOPIC ANALYSIS OF THE SLOWEST SYMBIOTIC NOVA AG PEG DURING QUIESCENCE

NASA Astrophysics Data System (ADS)

Sion, Edward Michael; Godon, Patrick; Katynski, Marcus; Mikolajewska, Joanna

2018-01-01

We present a far ultraviolet spectroscopic analysis of the slowest known symbiotic nova AG Peg (MIII giant + hot white dwarf; P_orb = 818.4 days) which underwent a nova explosion in 1850 followed by a very slow decline that did not end until ~ 1996, marking the beginning of queiscence. Eight years of quiescence ended in June 2015, when AG Peg exhibited a Z And-type outburst with an optical amplitude of ~ 3 magnitudes. We have carried out accretion disk and WD photosphere synthetic spectral modeling of a FUSE spectrum (Froning et al. 2014) obtained on June 5.618, 2003 during the quiescence intervai ~ 12 years before the 2015 outburst. The spectrum is heavily affected by ISM absorption as well as strong broad emission lines. We de-reddened the FUSE fluxes with E(B-V) = 0.10 which is the maximum galactic reddening in the direction of AG Peg and took the distance of 800 pc (Kenyon et al. 1993) but used a range of white dwarf masses, surface temperatures and disk inclination angles. Our analysis also incororates archival HST FOS spectra obtained in 1996 at the onset of quiescence, 147 years after the 1850 nova explosion. The results of our analysis are presented and implications are discussed.This work is supported in part by NASA ADP grant NNX17AF36G to Villanova University.

The active quiescence of HR Del (Nova Del 1967). The ex-nova HR Del

NASA Astrophysics Data System (ADS)

Selvelli, P.; Friedjung, M.

2003-04-01

This new UV study of the ex-nova HR Del is based on all of the data obtained with the International Ultraviolet Explorer (IUE) satellite, and includes the important series of spectra taken in 1988 and 1992 that have not been analyzed so far. This has allowed us to make a detailed study of both the long-timescale and the short-timescale UV variations, after the return of the nova, around 1981-1982, to the pre-outburst optical magnitude. After the correction for the reddening (EB-V=0.16), adopting a distance d =850 pc we have derived a mean UV luminosity close to LUV ~ 56 Lsun, the highest value among classical novae in ``quiescence". Also the ``average" optical absolute magnitude (Mv=+2.30) is indicative of a bright object. The UV continuum luminosity, the HeII 1640 Å emission line luminosity, and the optical absolute magnitude all give a mass accretion rate dot {M} very close to 1.4x 10-7 Msun yr-1, if one assumes that the luminosity of the old nova is due to a non-irradiated accretion disk. The UV continuum has declined by a factor less than 1.2 over the 13 years of the IUE observations, while the UV emission lines have faded by larger factors. The continuum distribution is well fitted with either a black body of 33 900 K, or a power-law Flambda ~ lambda -2.20. A comparison with the grid of models of Wade & Hubeny (\\cite{Wade}) indicates a low M1 value and a relatively high dot {M} but the best fittings to the continuum and the line spectrum come from different models. We show that the ``quiescent" optical magnitude at mv ~ 12 comes from the hot component and not from the companion star. Since most IUE observations correspond to the ``quiescent" magnitude at mv ~ 12, the same as in the pre-eruption stage, we infer that the pre-nova, for at least 70 years prior to eruption, was also very bright at near the same LUV, Mv, dot {M}, and T values as derived in the present study for the ex-nova. The wind components in the P Cyg profiles of the CIV 1550 Å and NV 1240 Å resonance lines are strong and variable on short timescales, with vedge up to -5000 km s-1, a remarkably high value. The phenomenology of the short-time variations of the wind indicates the presence of an inhomogeneous outflow. We discuss the nature of the strong UV continuum and wind features and the implications of the presence of a ``bright" state a long time before and after outburst on our present knowledge of the pre-nova and post-nova behavior. Based on observations made with the International Ultraviolet Explorer and de-archived from the ESA VILSPA Database. }

Quark-nova remnants. I. The leftover debris with applications to SGRs, AXPs, and XDINs

NASA Astrophysics Data System (ADS)

Ouyed, R.; Leahy, D.; Niebergal, B.

2007-10-01

We explore the formation and evolution of debris ejected around quark stars in the Quark Nova scenario, and the application to Soft Gamma-ray Repeaters (SGRs) and Anomolous X-ray Pulsars (AXPs). If an isolated neutron star explodes as a Quark Nova, an iron-rich shell of degenerate matter forms from its crust. This model can account for many of the observed features of SGRs and AXPs such as: (i) the two types of bursts (giant and regular); (ii) the spin-up and spin-down episodes during and following the bursts with associated increases in dot{P}; (iii) the energetics of the boxing day burst, SGR1806+20; (iv) the presence of an iron line as observed in SGR1900+14; (v) the correlation between the far-infrared and the X-ray fluxes during the bursting episode and the quiescent phase; (vi) the hard X-ray component observed in SGRs during the giant bursts, and (vii) the discrepancy between the ages of SGRs/AXPs and their supernova remnants. We also find a natural evolutionary relationship between SGRs and AXPs in our model which predicts that the youngest SGRs/AXPs are the most likely to exhibit strong bursting. Many features of X-ray Dim Isolated Neutron stars (XDINs) are also accounted for in our model such as, (i) the two-component blackbody spectra; (ii) the absorption lines around 300 eV; and (iii) the excess optical emission. Table 1 is only available in electronic form at http://www.aanda.org

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shara, Michael M.; Mizusawa, Trisha; Zurek, David

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 novamore » 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.« less

Location of Nearest Rocky Exoplanet Known

NASA Image and Video Library

2015-07-30

This sky map shows the location of the star HD 219134 (circle), host to the nearest confirmed rocky planet found to date outside of our solar system. The star lies just off the "W" shape of the constellation Cassiopeia and can be seen with the naked eye in dark skies. It actually has multiple planets, none of which are habitable. http://photojournal.jpl.nasa.gov/catalog/PIA19832

Measurement of the Neutrino Mixing Angle θ23 in NOvA

NASA Astrophysics Data System (ADS)

Adamson, P.; Aliaga, L.; Ambrose, D.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Augsten, K.; Aurisano, A.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blackburn, T.; Bolshakova, A.; Bromberg, C.; Brown, J.; Brunetti, G.; Buchanan, N.; Butkevich, A.; Bychkov, V.; Campbell, M.; Catano-Mur, E.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G. S.; Davies, J. P.; Derwent, P. F.; Desai, S.; Dharmapalan, R.; Ding, P.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G. J.; Frank, M. J.; Gabrielyan, M.; Gallagher, H. R.; Germani, S.; Ghosh, T.; Giri, A.; Gomes, R. A.; Goodman, M. C.; Grichine, V.; Group, R.; Grover, D.; Guo, B.; Habig, A.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Hylen, J.; Jediny, F.; Judah, M.; Kafka, G. K.; Kalra, D.; Kasahara, S. M. S.; Kasetti, S.; Keloth, R.; Kolupaeva, L.; Kotelnikov, S.; Kourbanis, I.; Kreymer, A.; Kumar, A.; Kurbanov, S.; Lang, K.; Lee, W. M.; Lin, S.; Liu, J.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W. A.; Marshak, M. L.; Matera, K.; Matveev, V.; Méndez, D. P.; Messier, M. D.; Meyer, H.; Miao, T.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Murphy, R.; Musser, J.; Nelson, J. K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Pandey, P.; Patterson, R. B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Phan-Budd, S.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Principato, C.; Psihas, F.; Radovic, A.; Rameika, R. A.; Rebel, B.; Reed, B.; Rocco, D.; Rojas, P.; Ryabov, V.; Sachdev, K.; Sail, P.; Samoylov, O.; Sanchez, M. C.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sheshukov, A.; Singh, J.; Singh, J.; Singh, P.; Singh, V.; Smolik, J.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R. L.; Tamsett, M. C.; Tas, P.; Thayyullathil, R. B.; Thomas, J.; Tian, X.; Tognini, S. C.; Tripathi, J.; Tsaris, A.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vold, A.; Vrba, T.; Wang, B.; Wetstein, M.; Whittington, D.; Wojcicki, S. G.; Wolcott, J.; Yadav, N.; Yang, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.; NOvA Collaboration

2017-04-01

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05 ×1 020 protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ23 mixing (θ23=π /4 ). Assuming the normal mass hierarchy, we find Δ m322 =(2.67 ±0.11 )×10-3 eV2 and sin2θ23 at the two statistically degenerate values 0.40 4-0.022+0.030 and 0.62 4-0.030+0.022, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6 σ significance.

Measurement of the neutrino mixing angle θ 23 in NOvA

DOE PAGES

Adamson, P.; Aliaga, L.; Ambrose, D.; ...

2017-04-10

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure ofmore » $$6.05\\times10^{20}$$ protons-on-target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal mixing ($$\\theta_{23} = \\pi/4$$). Assuming the normal mass hierarchy, we find $$\\Delta m^2 = (2.67 \\pm 0.11)\\times 10^{-3}$$ eV$^2$ and $$\\sin^2 \\theta_{23}$$ at the two statistically degenerate values $$0.404^{+0.030}_{-0.022}$$ and $$0.624^{+0.022}_{-0.030}$$, both at the 68% confidence level. Finally, our data disfavor the maximal mixing scenario with 2.6 $$\\sigma$$ significance.« less

Instabilities in Interacting Binary Stars

NASA Astrophysics Data System (ADS)

Andronov, I. L.; Andrych, K. D.; Antoniuk, K. A.; Baklanov, A. V.; Beringer, P.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Cook, L. M.; Cook, M.; Dubovský, P.; Godlowski, W.; Hegedüs, T.; Hoňková, K.; Hric, L.; Jeon, Y.-B.; Juryšek, J.; Kim, C.-H.; Kim, Y.; Kim, Y.-H.; Kolesnikov, S. V.; Kudashkina, L. S.; Kusakin, A. V.; Marsakova, V. I.; Mason, P. A.; Mašek, M.; Mishevskiy, N.; Nelson, R. H.; Oksanen, A.; Parimucha, S.; Park, J.-W.; Petrík, K.; Quiñones, C.; Reinsch, K.; Robertson, J. W.; Sergey, I. M.; Szpanko, M.; Tkachenko, M. G.; Tkachuk, L. G.; Traulsen, I.; Tremko, J.; Tsehmeystrenko, V. S.; Yoon, J.-N.; Zola, S.; Shakhovskoy, N. M.

2017-07-01

The types of instability in the interacting binary stars are briefly reviewed. The project “Inter-Longitude Astronomy” is a series of smaller projects on concrete stars or groups of stars. It has no special funds, and is supported from resources and grants of participating organizations, when informal working groups are created. This “ILA” project is in some kind similar and complementary to other projects like WET, CBA, UkrVO, VSOLJ, BRNO, MEDUZA, AstroStatistics, where many of us collaborate. Totally we studied 1900+ variable stars of different types, including newly discovered variables. The characteristic timescale is from seconds to decades and (extrapolating) even more. The monitoring of the first star of our sample AM Her was initiated by Prof. V.P. Tsesevich (1907-1983). Since more than 358 ADS papers were published. In this short review, we present some highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types: classical (AM Her, QQ Vul, V808 Aur = CSS 081231:071126+440405, FL Cet), asynchronous (BY Cam, V1432 Aql), intermediate (V405 Aql, BG CMi, MU Cam, V1343 Her, FO Aqr, AO Psc, RXJ 2123, 2133, 0636, 0704) polars and magnetic dwarf novae (DO Dra) with 25 timescales corresponding to different physical mechanisms and their combinations (part “Polar”); negative and positive superhumpers in nova-like (TT Ari, MV Lyr, V603 Aql, V795 Her) and many dwarf novae stars (“Superhumper”); eclipsing “non-magnetic” cataclysmic variables(BH Lyn, DW UMa, EM Cyg; PX And); symbiotic systems (“Symbiosis”); super-soft sources (SSS, QR And); spotted (and not spotted) eclipsing variables with (and without) evidence for a current mass transfer (“Eclipser”) with a special emphasis on systems with a direct impact of the stream into the gainer star's atmosphere, which we propose to call “Impactor” (short from “Extreme Direct Impactor”), or V361 Lyr-type stars. Other parts of the ILA project are “Stellar Bell” (interesting pulsating variables of different types and periods - M, SR, RV Tau, RR Lyr, Delta Sct with changes of characteristics) and “Novice”(=“New Variable”) discoveries and classification based on special own observations and data mining with a subsequent monitoring for searching and studying possible multiple components of variability. Special mathematical methods have been developed to create a set of complementary software for statistically optimal modeling of variable stars of different types.

A Hubble Space Telescope survey for novae in M87.I. light and color curves, spatial distributions, and the nova rate

DOE PAGES

Shara, Michael M.; Doyle, Trisha F.; Lauer, Tod R.; ...

2016-11-08

The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae (CNe) and nine fainter, likely very slow, and/or symbiotic novae. In this first paper of a series, we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. Conservatively using only the 32 brightest CNe we derive a nova rate for M87:more » $${363}_{-45}^{+33}$$ novae yr –1. We also derive the luminosity-specific classical nova rate for this galaxy, which is $${7.88}_{-2.6}^{+2.3}\\,{\\mathrm{yr}}^{-1}/{10}^{10}\\,{L}_{\\odot }{,}_{K}$$. Both rates are 3–4 times higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. As a result, we suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow novae near the centers of galaxies.« less

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.

Mobile Geospatial Information Systems for Land Force Operations: Analysis of Operational Needs and Research Opportunities

DTIC Science & Technology

2010-03-01

Dynamics Itronix Duo-Touch II SmartPhones 1. Apple iPhone 2. Blackberry Smartphone 3. Cassiopeia E-105 4. Hewlett Packard (HP) iPAQ 910 Smartphone...Mobile GIS Page 2-39 Blackberry Smartphone Housekeeping Functions (internal device functionality, status, and security) 1 Maintain awareness of...sensor status and alarms SW (comments) 2 Plan storage SW 3 Development Environment Blackberry OS Can additional programmable

Revised coordinates of variable stars in Cassiopeia

NASA Astrophysics Data System (ADS)

Nesci, R.

2018-02-01

The identification of the variable stars published on IBVS 3573 has ben revised on the basis of the original (unpublished) finding charts. Cross check with the 2MASS catalog has been made to get more accurate coordinates and to confirm their nature from their , colors. The Mira stars, given their known periods, could be used with the astrometric parallaxes of the forthcoming Gaia catalog to improve the Period-Luminosity relation.

A hyperspectral view of Cassiopeia A

NASA Astrophysics Data System (ADS)

Alarie, Alexandre; Bilodeau, Antoine; Drissen, Laurent

2014-07-01

We used the imaging Fourier transform spectrometer Spectromètre Imageur de l'Observatoire du Mont-Mégantic (SpIOMM) to obtain hyperspectral cubes of the young supernova remnant Cassiopeia A (Cas A). The cubes contain over 5000 spatially resolved spectra covering the spectral range 6480-7050 Å. We first investigate the slow-moving N-rich quasi-stationary flocculi by measuring their radial velocity as well as the [N II] λ6583/Hα ratio. No correlation between their radial velocity and [N II] λ6583/Hα ratio with their location has been found. We used multi-epoch observations from the Hubble Space Telescope to create a proper motion map, showing the displacement of several filaments over the most part of Cas A. Combining data from SpIOMM and Hubble, we re-evaluate the distance to Cas A and obtained 3.33 ± 0.10 kpc, which is in good agreement with previous estimates. Finally, we obtain a three-dimensional spatial view of the [S II] λλ6716, 6731 emissions showing their location, expansion velocity and the [S II] doublet line ratio for multiple locations in the remnant. The velocity asymmetry reported by previous analyses is clearly visible. Also, the [S II] doublet ratio (with a mean value of 0.5 ± 0.2) indicates a very high and variable electronic density throughout the remnant.

Getting to Know the Neighbors: Deep Imaging of the Andromeda Satellite Dwarf Galaxy Cassiopeia III with WIYN pODI

NASA Astrophysics Data System (ADS)

Smith, Madison; Rhode, Katherine L.; Janowiecki, Steven

2016-01-01

We present results from WIYN pODI imaging of Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), an Andromeda satellite dwarf galaxy recently discovered by Martin et al. (2013) in Pan-STARRS1 survey data. Detailed studies of satellite dwarf galaxies in the Local Group and its environs provide important insight into how low-mass galaxies form and evolve as well as how more massive galaxies are assembled in a hierarchical universe. The goal of this project is to obtain deep, wide-field photometry of Cas III in order to study its stellar population in more detail. The images used for this analysis were taken in October 2013 with the 24' x 24' pODI camera on the WIYN 3.5-m telescope in the SDSS g and i filters. Calibrated photometry was performed on all point sources in the g and i images and then used to quantify the radial distribution of stars in Cas III and to construct a color-magnitude diagram (CMD). We present this CMD along with a map of the resolved stellar population and measurements of the galaxy magnitude and structural properties. This research was supported by the NSF Research Experiences for Undergraduates program (grant number AST-1358980).

A Chandra X-Ray Survey of Ejecta in the Cassiopeia A Supernova Remnant

NASA Technical Reports Server (NTRS)

Hwang, Una; Laming, J. Martin

2011-01-01

We present a survey of the X-ray emitting ejecta in the Cassiopeia A supernova remnant based on an extensive analysis of over 6000 spectral regions extracted on 2.5-10" angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray emitting ejecta as well as showing the distribution of the mass of various elements over the remnant. The total shocked Fe mass appears to be roughly 0.14 Solar Mass, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si-burning and that associated with alpha-rich freeze-out, with a mass ratio of approximately 2:1. Surprisingly, essentially all of this Fe (both components) is well outside the central regions of the SNR, presumably having been ejected by hydrodynamic instabilities during the explosion. We discuss this, and its implications for the neutron star kick.

The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae

NASA Astrophysics Data System (ADS)

Shara, Michael M.; Prialnik, Dina; Hillman, Yael; Kovetz, Attay

2018-06-01

Models have long predicted that the frequency-averaged masses of white dwarfs (WDs) in Galactic classical novae are twice as large as those of field WDs. Only a handful of dynamically well-determined nova WDs masses have been published, leaving the theoretical predictions poorly tested. The recurrence time distributions and mass accretion rate distributions of novae are even more poorly known. To address these deficiencies, we have combined our extensive simulations of nova eruptions with the Strope et al. and Schaefer databases of outburst characteristics of Galactic classical and recurrent novae (RNe) to determine the masses of 92 WDs in novae. We find that the mean mass (frequency-averaged mean mass) of 82 Galactic classical novae is 1.06 (1.13) M ⊙, while the mean mass of 10 RNe is 1.31 M ⊙. These masses, and the observed nova outburst amplitude and decline time distributions allow us to determine the long-term mass accretion rate distribution of classical novae. Remarkably, that value is just 1.3 × 10‑10 M ⊙ yr‑1, which is an order of magnitude smaller than that of cataclysmic binaries in the decades before and after classical nova eruptions. This predicts that old novae become low-mass transfer rate systems, and hence dwarf novae, for most of the time between nova eruptions. We determine the mass accretion rates of each of the 10 known Galactic recurrent nova, finding them to be in the range of 10‑7–10‑8 M ⊙ yr‑1. We are able to predict the recurrence time distribution of novae and compare it with the predictions of population synthesis models.

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

NASA Astrophysics Data System (ADS)

Shara, Michael M.; Doyle, Trisha F.; Lauer, Tod R.; Zurek, David; Neill, J. D.; Madrid, Juan P.; Mikołajewska, Joanna; Welch, D. L.; Baltz, Edward A.

2016-11-01

The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae (CNe) and nine fainter, likely very slow, and/or symbiotic novae. In this first paper of a series, we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. Conservatively using only the 32 brightest CNe we derive a nova rate for M87: {363}-45+33 novae yr‑1. We also derive the luminosity-specific classical nova rate for this galaxy, which is {7.88}-2.6+2.3 {yr}}-1/{10}10 {L}ȯ {,}K. Both rates are 3–4 times higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. We suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow novae near the centers of galaxies. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

The Galactic Nova Rate Revisited

NASA Astrophysics Data System (ADS)

Shafter, A. W.

2017-01-01

Despite its fundamental importance, a reliable estimate of the Galactic nova rate has remained elusive. Here, the overall Galactic nova rate is estimated by extrapolating the observed rate for novae reaching m≤slant 2 to include the entire Galaxy using a two component disk plus bulge model for the distribution of stars in the Milky Way. The present analysis improves on previous work by considering important corrections for incompleteness in the observed rate of bright novae and by employing a Monte Carlo analysis to better estimate the uncertainty in the derived nova rates. Several models are considered to account for differences in the assumed properties of bulge and disk nova populations and in the absolute magnitude distribution. The simplest models, which assume uniform properties between bulge and disk novae, predict Galactic nova rates of ˜50 to in excess of 100 per year, depending on the assumed incompleteness at bright magnitudes. Models where the disk novae are assumed to be more luminous than bulge novae are explored, and predict nova rates up to 30% lower, in the range of ˜35 to ˜75 per year. An average of the most plausible models yields a rate of {50}-23+31 yr-1, which is arguably the best estimate currently available for the nova rate in the Galaxy. Virtually all models produce rates that represent significant increases over recent estimates, and bring the Galactic nova rate into better agreement with that expected based on comparison with the latest results from extragalactic surveys.

Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

DOE PAGES

Adamson, P.; Aliaga, L.; Ambrose, D.; ...

2017-10-30

Here, we report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05 × 10 20 protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 ± 9.7(stat) ± 9.4(syst) events predicted assuming mixing only occurs between active neutrino species. No evidence for νμ→νs transitions is found. Interpreting these results within a 3+1 model, we place constraints on the mixing angles θ 24more » < 20.8° and θ 34 < 31.2° at the 90% C.L. for 0.05 eV 2 ≤ Δm 41 2 ≤ 0.5 eV 2, the range of mass splittings that produce no significant oscillations over the Near Detector baseline.« less

Observing the Next Galactic Supernova with the NOvA Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vasel, Justin A.; Sheshukov, Andrey; Habig, Alec

The next galactic core-collapse supernova will deliver a wealth of neutrinos which for the first time we are well-situated to measure. These explosions produce neutrinos with energies between 10 and 100 MeV over a period of tens of seconds. Galactic supernovae are relatively rare events, occurring with a frequency of just a few per century. It is therefore essential that all neutrino detectors capable of detecting these neutrinos are ready to trigger on this signal when it occurs. This poster describes a data-driven trigger which is designed to detect the neutrino signal from a galactic core-collapse supernova with the NOvAmore » detectors. The trigger analyzes 5ms blocks of detector activity and applies background rejection algorithms to detect the signal time structure over the background. This background reduction is an essential part of the process, as the NOvA detectors are designed to detect neutrinos from Fermilab's NuMI beam which have an average energy of 2GeV--well above the average energy of supernova neutrinos.« less

{gamma}-ray spectroscopy study of states in {sup 27}Si relevant for the {sup 26}Al{sup m}(p,{gamma}){sup 27}Si reaction in novae and supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lotay, G.; Woods, P. J.; Seweryniak, D.

2009-11-15

The heavy-ion, fusion-evaporation reaction {sup 12}C({sup 16}O,n) was used to identify {gamma}-decay transitions from excited states in {sup 27}Si above the proton threshold. The precise level energy measurements, J{sup {pi}} assignments, and lifetime measurements of astrophysically important {sup 26}Al{sup m}+p resonances have allowed an evaluation of the {sup 26}Al{sup m}(p,{gamma}){sup 27}Si reaction rate. An l{sub p}=0 resonance has been newly identified at a center-of-mass energy in the {sup 26}Al{sup m}+p system of 146.3(3) keV and is expected to dominate the rate for low stellar temperatures. In addition, an l{sub p}=1 resonance has been identified at 378.3(30) keV and is likelymore » to dominate the rate at high astrophysical temperatures, such as those found in oxygen-neon novae and core-collapse supernovae.« less

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.

A Public Set of Synthetic Spectra from Expanding Atmospheres for X-Ray Novae. I. Solar Abundances

NASA Astrophysics Data System (ADS)

van Rossum, Daniel R.

2012-09-01

X-ray grating observations have revealed great detail in the spectra of novae in the Super Soft Source (SSS) phase. Notable features in the SSS spectra are blueshifted absorption lines, P-Cygni line profiles, and the absence of strong ionization edges, all of which are indicators of an expanding atmosphere. We present, and make publicly available, a set of 672 wind-type (WT) synthetic spectra, obtained from the expanding NLTE SSS models introduced in Van Rossum & Ness with the PHOENIX stellar atmosphere code. The set presented in this paper is limited to solar abundances with the aim to focus on the basic model parameters and their effect on the spectra, providing the basis upon which abundance effects can be studied using a much bigger non-solar set in the next paper in this series. We fit the WT spectra to the five grating spectra taken in the SSS phase of nova V4743 Sgr 2003 as an example application of the WT models. Within the limits of solar abundances we demonstrate that the following parameters are constrained by the data (in order of decreasing accuracy): column density N H, bolometric luminosity L bol, effective temperature T eff, white dwarf radius R, wind asymptotic velocity v ∞, and the mass-loss rate \\dot{M}. The models are also sensitive to the assumed white dwarf mass M WD but the effect on the spectra can largely be compensated by the other model parameters. The WT spectra with solar abundances fit the data better than abundance optimized hydrostatic models.

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 contributor, and the lower states are collisionally quenched but emit from the low density surroundings. Absorption lines of Fe-peak ions formed in the Mira wind were visible as P Cyg profiles at low velocity before Day 69, around the time of the X-ray peak and we identified many absorption transitions without accompanying emission for metal lines. The H Balmer lines showed strong P Cyg absorption troughs that weakened during the 2010 observing period, through Day 128. The Fe-peak line profiles and flux variations were different for permitted and forbidden transitions: the E1 transitions were not visible after Day 128 but had shown a narrow peak superimposed on an extended (200 km/s) blue wing, while the M1 and E2 transitions persisted to Day 529, the last observation, and showed extended redshifted wings up of the same velocity. We distinguish the components from the shock, the photoionized environment, and the chromosphere and inner Mira wind using spectra taken more than one year after outburst. The multiple shells and radiative excitation phenomenology are similar to those recently cited for GRBs and SNIa .

Proper-motion age dating of the progeny of Nova Scorpii AD 1437.

PubMed

Shara, M M; Iłkiewicz, K; Mikołajewska, J; Pagnotta, A; Bode, M F; Crause, L A; Drozd, K; Faherty, J; Fuentes-Morales, I; Grindlay, J E; Moffat, A F J; Pretorius, M L; Schmidtobreick, L; Stephenson, F R; Tappert, C; Zurek, D

2017-08-30

'Cataclysmic variables' are binary star systems in which one star of the pair is a white dwarf, and which often generate bright and energetic stellar outbursts. Classical novae are one type of outburst: when the white dwarf accretes enough matter from its companion, the resulting hydrogen-rich atmospheric envelope can host a runaway thermonuclear reaction that generates a rapid brightening. Achieving peak luminosities of up to one million times that of the Sun, all classical novae are recurrent, on timescales of months to millennia. During the century before and after an eruption, the 'novalike' binary systems that give rise to classical novae exhibit high rates of mass transfer to their white dwarfs. Another type of outburst is the dwarf nova: these occur in binaries that have stellar masses and periods indistinguishable from those of novalikes but much lower mass-transfer rates, when accretion-disk instabilities drop matter onto the white dwarfs. The co-existence at the same orbital period of novalike binaries and dwarf novae-which are identical but for their widely varying accretion rates-has been a longstanding puzzle. Here we report the recovery of the binary star underlying the classical nova eruption of 11 March AD 1437 (refs 12, 13), and independently confirm its age by proper-motion dating. We show that, almost 500 years after a classical-nova event, the system exhibited dwarf-nova eruptions. The three other oldest recovered classical novae display nova shells, but lack firm post-eruption ages, and are also dwarf novae at present. We conclude that many old novae become dwarf novae for part of the millennia between successive nova eruptions.

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.

Investigating the Current State of V1535 Sco

NASA Astrophysics Data System (ADS)

Linford, Justin

2017-09-01

We request 25 ks of time on the ACIS instrument to image the nova system V1535 Sco in quiescence. The observations will reveal several details about the physics of the system. The presence of X-rays and variations in the light curve will prove the resumption of accretion onto the white dwarf. Absorption, especially in the soft X-rays, will probe the presence of a strong stellar wind from the companion star. The X-ray spectrum will place limits on the white dwarf mass.

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.

30 CFR 7.23 - Application requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.23 Application requirements. (a) Brattice cloth. A single application may address two or more...

30 CFR 7.23 - Application requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.23 Application requirements. (a) Brattice cloth. A single application may address two or more...

30 CFR 7.23 - Application requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.23 Application requirements. (a) Brattice cloth. A single application may address two or more...

Environmental Assessment: Peterson AFB Military Housing Privatization Initiative, El Paso County, Colorado

DTIC Science & Technology

2006-06-08

would sublease the land from Peterson AFB, and would maintain and manage the housing area for a minimum of 723 military families for 50 years. Under...housing area for a minimum of 723 military families for 50 years. Under the no action alternative, the Air Force would not implement the MHPI at...Peterson AFB, and would maintain and manage the housing area for a minimum of 723 military families for 50 years. No Action Alternative Under the no

A statistical analysis of IUE spectra of dwarf novae and nova-like stars

NASA Technical Reports Server (NTRS)

Ladous, Constanze

1990-01-01

First results of a statistical analysis of the IUE International Ultraviolet Explorer archive on dwarf novae and nova like stars are presented. The archive contains approximately 2000 low resolution spectra of somewhat over 100 dwarf novae and nova like stars. Many of these were looked at individually, but so far the collective information content of this set of data has not been explored. The first results of work are reported.

Gamma Rays from Classical Novae

NASA Technical Reports Server (NTRS)

1997-01-01

NASA at the University of Chicago, provided support for a program of theoretical research into the nature of the thermonuclear outbursts of the classical novae and their implications for gamma ray astronomy. In particular, problems which have been addressed include the role of convection in the earliest stages of nova runaway, the influence of opacity on the characteristics of novae, and the nucleosynthesis expected to accompany nova outbursts on massive Oxygen-Neon-Magnesium (ONeMg) white dwarfs. In the following report, I will identify several critical projects on which considerable progress has been achieved and provide brief summaries of the results obtained:(1) two dimensional simulation of nova runaway; (2) nucleosynthesis of nova modeling; and (3) a quasi-analytic study of nucleosynthesis in ONeMg novae.

Continuity and Change in Cosmological Ideas in Spain Between the Sixteenth and Seventeenth Centuries: The Impact of Celestial Novelties

NASA Astrophysics Data System (ADS)

Navarro Brotóns, Víctor

The star which became visible in 1572 in the constellation of Cassiopeia (identified by twentieth-century astronomers as a Type I supernova), and the works and polemics to which it gave rise, marked an important stage in the abandonment of Aristotelian and medieval cosmology and their replacement by the idea of the infinite - or indefinite - universe of modern physics and astronomy.

Student Measurements of STFA 14 AC at Vanguard Preparatory School

NASA Astrophysics Data System (ADS)

Gillette, Sean; Archuleta, Alex; Diaz, Lizbeth; Gillespie, Kyle; Gosney, Timothy; Johnson, Stephen; Mohan, Nikita; Rajacich, Jacob; Roehl, Nathaniel; Sharpe, Scotty; Whitt, Kahaloha

2016-01-01

Eighth grade students at Vanguard Preparatory School measured the double star STFA 14 AC using a Bader Planetarium Micro Guide eyepiece. Navi (Gamma Cassiopeiae) was used as the ca libration star. The calculated means of multiple observations of STFA 14 AC resulted in a separation of 53.3" and a position angle of 2.0°. These measurements were compared to the most recent values in the Washington Double Star Catalog.

Permeation of deuterium implanted into V-15Cr-5Ti

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Longhurst, G. R.; Struttmann, D. A.

1987-02-01

Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D 3+ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4 × 10 -8 exp( -0.11 eV/ kT) (m 2/s), over the temperature range 723 K to 823 K.

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

NASA Astrophysics Data System (ADS)

Tomaney, Austin Bede

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

Highlights of Odessa Branch of AN in 2017

NASA Astrophysics Data System (ADS)

Andronov, I. L.

2017-12-01

An annual report with a list of publications. Our group works on the variable star research within the international campaign "Inter-Longitude Astronomy" (ILA) based on temporarily working groups in collaboration with Poland, Slovakia, Korea, USA and other countries. A recent self-review on highlights was published in 2017. Our group continues the scientific school of Prof. Vladymir P. Tsesevich (1907 - 1983). Another project we participate is "AstroInformatics". The unprecedented photo-polarimetric monitoring of a group of AM Her - type magnetic cataclysmic variable stars was carried out since 1989 (photometry in our group - since 1978). A photometric monitoring of the intermediate polars (MU Cam, V1343 Her, V2306 Cyg et al.) was continued to study rotational evolution of magnetic white dwarfs. The super-low luminosity state was discovered in the outbursting intermediate polar = magnetic dwarf nova DO Dra. Previously typical low state was some times interrupted by outbursts, which are narrower than usual dwarf nova outbursts. Once there were detected TPO - "Transient Periodic Oscillations". The orbital and quasi-periodic variability was recently studied. Such super-low states are characteristic for nova-like variables (e.g. MV Lyr, TT Ari) or intermediate polars, but unusual for the dwarf novae. The electronic "Catalogue of Characteristics and Atlas of the Light Curves of Newly-Discovered Eclipsing Binary Stars" was compiled and is being prepared for publication. The software NAV ("New Algol Variable") with specially developed algorithms was used. It allows to determine the begin and end of the eclipses even in EB and EW - type stars, whereas the current classification (GCVS, VSX) claims that the begin and end of eclipses only in the EA - type objects. The further improvements of the NAV algorithm were comparatively studied. The "Wall-Supported Polynomial" (WSP) algoritms were implemented in the software MAVKA for statistically optimal modeling of flat eclipses and exoplanet transitions. MAVKA was used for studies of effects of the mass transfer and presence of the third components in close binary stellar systems and analysis of the poorly studied eclipsing binary 2MASS J20355082+5242136. Atlas of the Light Curves and Phase Plane Portraits of Selected Long-Period Variables was compiled.

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.

The extinction law in the open cluster NGC 457 and the intrinsic energy distribution of Phi Cassiopeiae (F0 Ia)

NASA Technical Reports Server (NTRS)

Rosenzweig, P.; Morrison, N. D.

1986-01-01

Five early B-type stars near the main-sequence turnoff in NGC 457 have been observed at low dispersion with the short-wavelength prime and the long-wavelength redundant cameras of the IUE satellite. The equivalent widths of spectral features that are particularly strong and sensitive to temperature and luminosity were computed in the cluster stars and in 20 lightly reddened stars of types O9-B3 and luminosity classes III-V. The comparison of the equivalent widths provides a reliable method for finding matching pairs. Having identified the best comparison star for each program star, binned fluxes were used to determine the mean extinction curve. In order to cover the visible region, monochromatic fluxes of Phi Cas were derived from observations with the intensified Reticon scanner mounted on the No. 2 0.9 m telescope of KPNO, and they were dereddened with the mean extinction curve of Savage and Mathis. Thus, the intrinsic energy distribution of Phi Cas were determined from 1500 to 5800 A for use in a detailed model-atmosphere analysis.

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A Hubble Space Telescope survey for Novae in M87. II. Snuffing out the maximum magnitude–rate of decline relation for novae as a non-standard candle, and a prediction of the existence of ultrafast novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shara, Michael M.; Doyle, Trisha; Lauer, Tod R.

The extensive grid of numerical simulations of nova eruptions first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are inmore » the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10 –7–10 –8 M ⊙, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. As a result, these same models predict the existence of ultrafast novae that display decline times, t 2, to be as short as five hours. We outline a strategy for their future detection.« less

A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude–Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shara, Michael M.; Doyle, Trisha; Zurek, David

The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giantmore » elliptical galaxy M87 as they are in the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10{sup −7}–10{sup −8} M {sub ⊙}, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. These same models predict the existence of ultrafast novae that display decline times, t {sub 2,} to be as short as five hours. We outline a strategy for their future detection.« less

A Hubble Space Telescope survey for Novae in M87. II. Snuffing out the maximum magnitude–rate of decline relation for novae as a non-standard candle, and a prediction of the existence of ultrafast novae

DOE PAGES

Shara, Michael M.; Doyle, Trisha; Lauer, Tod R.; ...

2017-04-20

The extensive grid of numerical simulations of nova eruptions first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are inmore » the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10 –7–10 –8 M ⊙, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. As a result, these same models predict the existence of ultrafast novae that display decline times, t 2, to be as short as five hours. We outline a strategy for their future detection.« less

A space bourne crystal diffraction telescope for the energy range of nuclear transitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

von Ballmoos, P.; Naya, J.E.; Albernhe, F.

1995-10-01

Recent experimental work of the Toulouse-Argonne collaboration has opened for perspective of a focusing gamma-ray telescope operating in the energy range of nuclear transitions, featuring unprecedented sensitivity, angular and energy resolution. The instrument consists of a tunable crystal diffraction lens situated on a stabilized spacecraft, focusing gamma-rays onto a small array of Germanium detectors perched on an extendible boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 in., an energy resolution of 2 keV and a 3 {sigma} narrow line sensitivity of a few times 10{sup {minus}7} photons s{supmore » {minus}1} cm{sup {minus}2} (10{sup 6} sec observation). This instrumental concept permits observation of any identified source at any selected line-energy in a range of typically 200 keV to 1300 keV. The resulting ``sequential`` operation mode makes sites of explosive nucleosynthesis natural scientific objectives for such a telescope: the nuclear lines of extragalactic supernovae ({sup 56}Ni, {sup 44}Ti, {sup 60}Fe) and galactic novae (p{sup {minus}}p{sup +} line, {sup 7}Be) are accessible to observation, one at a time, due to the erratic appearance and the sequence of half-lifes of these events. Other scientific objectives, include the narrow 511 keV line from galactic broad class annihilators (such as 1E1740-29, nova musca) and possible redshifted annihilation lines from AGN`s.« less

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.

The Progenitor and Remnant of the Helium Nova V445 Puppis

NASA Astrophysics Data System (ADS)

Goranskij, V.; Shugarov, S.; Zharova, A.; Kroll, P.; Barsukova, E. A.

2010-10-01

V445 Pup was a peculiar nova with no hydrogen spectral lines during the outburst. The spectrum contained strong emission lines of carbon, oxygen, calcium, sodium, and iron. We have performed digital processing of photographic images of the V445 Pup progenitor using astronomical plate archives. The brightness of the progenitor in the B band was 14.3m. It was a periodic variable star, its most probable period being 0.650654+/-0.000011 days. The light curve shape suggests that the progenitor was a common-envelope binary with a spot on the surface and variable surface brightness. The spectral energy distribution of the progenitor between 0.44 and 2.2 microns was similar to that of an A0V type star. After the explosion in 2001, the dust was formed in the ejecta, and the star became a strong infrared source. This resulted in the star's fading below 20m in the V band. Our CCD BVR observations acquired between 2003 and 2009 suggest that the dust absorption minimum finished in 2004, and the remnant reappeared at the level of 18.5m V. The dust dispersed but a star-like object was absent in frames taken in the K band with the VLT adaptive optics. Only expanding ejecta of the explosion were seen in these frames till March 2007. No reddened A0V type star reappeared in the spectral energy distribution. The explosion of V445 Pup in 2000 was a helium flash on the surface of a CO-type white dwarf. Taking into account the results of modern dynamic calculations, we discuss the possibility of a white-dwarf core detonation triggered by the helium flash and the observational evidence for it. Additionally, the common envelope of the system was lost in the explosion. Destruction in the system and mass loss from its components exclude the future SN Ia scenario for V445 Pup.

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

NASA Astrophysics Data System (ADS)

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.

2013-08-01

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-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/\\dot{P}=+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) × 10-7 M ⊙ yr-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 νvpropν1.0, although the narrow ultraviolet region has a tilt with a fit of f νvpropν1/3. 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 source. We confirm the extinction measure from IUE with E(B - V) = 0.25 ± 0.02 mag.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Bradley E.; Landolt, Arlo U.; Linnolt, Michael

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 themore » 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 source. We confirm the extinction measure from IUE with E(B - V) = 0.25 {+-} 0.02 mag.« less

Hubble COS Spectroscopy of the Dwarf Nova CW Mon: The White Dwarf in Quiescence?

PubMed

Hause, Connor; Sion, Edward M; Godon, Patrick; Boris, T Gänsicke; Szkody, Paula; de Martino, Domitilla; Pala, Anna

2017-08-01

We present a synthetic spectral analysis of the HST COS spectrum of the U Geminorum-type dwarf nova CW Mon, taken during quiescence as part of our COS survey of accreting white dwarfs in Cataclysmic Variables. We use synthetic photosphere and optically thick accretion disk spectra to model the COS spectrum as well as archival IUE spectra obtained decades ago when the system was in an even deeper quiescent state. Assuming a reddening of E(B-V)=0.06, an inclination of 60° (CW Mon has eclipses of the accretion disk, and a white dwarf mass of 0.8 M ⊙ , our results indicate the presence of a 22-27,000 K white dwarf and a low mass accretion rate [Formula: see text], for a derived distance o ~200 to ~300 pc.

Inter-Longitude Astronomy (ILA) Project: Current Highlights And Perspectives. I. Magnetic vs. Non-Magnetic Interacting Binary Stars

NASA Astrophysics Data System (ADS)

Andronov, I. L.; Antoniuk, K. A.; Baklanov, A. V.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Dubovsky, P. A.; Han, W.; Hegedus, T.; Henden, A.; Hric, L.; Chun-Hwey, Kim; Yonggi, Kim; Kolesnikov, S. V.; Kudzej, I.; Liakos, A.; Niarchos, P. G.; Oksanen, A.; Patkos, L.; Petrik, K.; Pit', N. V.; Shakhovskoy, N. M.; Virnina, N. A.; Yoon, J.; Zola, S.

2010-12-01

We present a review of highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types classical, asynchronous, intermedi ate polars with 25 timescales corresponding to differ ent physical mechanisms and their combinations (part "Polar"); negative and positive superhumpers in nova- like and dwarf novae stars ("Superhumper"); symbiotic ("Symbiosis"); eclipsing variables with and without ev idence for a current mass transfer ("Eclipser") with a special emphasis on systems with a direct impact of the stream into the gainor star's atmosphere, which we propose to call "Impactors", or V361 Lyr-type stars. Other parts of the ILA project are "Stellar Bell" (pul sating variables of different types and periods - M, SR, RV Tau, RR Lyr, Delta Sct) and "New Variable".

COLLIMATION AND ASYMMETRY OF THE HOT BLAST WAVE FROM THE RECURRENT NOVA V745 Sco

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drake, Jeremy J.; Kashyap, Vinay; Delgado, Laura

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 10{sup 7} 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{sup 1}, an FWHM of 1200 ± 30 km s{sup 1}, and an average net blueshift of 165more » ± 10 km s{sup 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 10{sup 43} erg and confirms an ejected mass of approximately 10{sup 7} M {sub ⊙}. 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.« less

Dust around the Cool Component of D-Type Symbiotic Binaries

NASA Astrophysics Data System (ADS)

Jurkic, Tomislav; Kotnik-Karuza, Dubravka

2018-04-01

D type symbiotic binaries are an excellent astrophysical laboratory for investigation of the dust properties and dust formation under the influence of theMira stellar wind and nova activity and of the mass loss and mass transfer between components in such a widely separated system. We present a study of the properties of circumstellar dust in symbiotic Miras by use of long-term near-IR photometry and colour indices. The published JHKL magnitudes of o Ceti, RX Pup, KM Vel, V366 Car, V835 Cen, RR Tel, HM Sge and R Aqr have been collected, analyzed and corrected for short-term variations caused by Mira pulsations. Assuming spherical temperature distribution of the dust in the close neighbourhood of the Mira, the DUSTY code was used to solve the radiative transfer in order to determine the dust temperature and its properties in each particular case. Common dust properties of the symbiotic Miras have been found, suggesting similar conditions in the condensation region of the studied symbiotic Miras. Silicate dust with the inner dust shell radius determined by the dust condensation and with the dust temperature of 900-1200 K can fully explain the observed colour indices. R Aqr is an exception and showed lower dust temperature of 650 K. Obscuration events visible in light curves can be explained by variable dust optical depth with minimal variations of other dust properties. More active symbioticMiras that underwent recent nova outbursts showed higher dust optical depths and larger maximum grain sizes of the order of μm, which means that the post-nova activity could stimulate the dust formation and the grain growth. Optically thicker dust shells and higher dust condensation temperatures have been found in symbiotic Miras compared to their single counterparts, suggesting different conditions for dust production.

Active Optical Devices and Applications. Volume 228

DTIC Science & Technology

1980-04-01

Research Center, Minneapolis, Minnesota 55413 Abstract In this paper a control engineer’s point of view of the Large Space Structure (LSS) problem is...CASSIOPEIA SUPERNOVA REMNANT GALAXIES IN VIRGO CLUSTER QUASAR 3C273 CRAB PULSAR Figure 2. A collage of images of X-ray sources obtained with the HEAO...Telescope. Yet ST will not be able to study vari- able stars (primary distance indicators) to the Virgo cluster of galaxies and beyond. This cluster is

Asymmetries in Core Collapse Supernovae Revealed by Maps of Radioactive Titanium

NASA Technical Reports Server (NTRS)

Grefenstette, B. W.; Harrison, F. A.; Boggs, S. E.; Reynolds, S. P.; Fryer, C. L.; Madsen, K. K.; Wik, D. R.; Zoglauer, A.; Ellinger, C. I.; Alexander, D. M.;

Lacerta I and Cassiopeia III. Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3π Pan-STARRS1 Survey

NASA Astrophysics Data System (ADS)

Martin, Nicolas F.; Slater, Colin T.; Schlafly, Edward F.; Morganson, Eric; Rix, Hans-Walter; Bell, Eric F.; Laevens, Benjamin P. M.; Bernard, Edouard J.; Ferguson, Annette M. N.; Finkbeiner, Douglas P.; Burgett, William S.; Chambers, Kenneth C.; Hodapp, Klaus W.; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Price, Paul A.; Tonry, John L.; Wainscoat, Richard J.

2013-07-01

We report the discovery of two new dwarf galaxies, Lacerta I/Andromeda XXXI (Lac I/And XXXI) and Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), in stacked Pan-STARRS1 r P1- and i P1-band imaging data. Both are luminous systems (MV ~ -12) located at projected distances of 20.°3 and 10.°5 from M31. Lac I and Cas III are likely satellites of the Andromeda galaxy with heliocentric distances of 756^{+44}_{-28}\\,kpc and 772^{+61}_{-56}\\,kpc, respectively, and corresponding M31-centric distances of 275 ± 7 kpc and 144^{+6}_{-4}\\,kpc. The brightest of recent Local Group member discoveries, these two new dwarf galaxies owe their late discovery to their large sizes (r_h = 4.2^{+0.4}_{-0.5} arcmin or 912^{+124}_{-93}\\,pc for Lac I r_h = 6.5^{+1.2}_{-1.0} arcmin or 1456 ± 267 pc for Cas III) and consequently low surface brightness (μ0 ~ 26.0 mag arcsec-2), as well as to the lack of a systematic survey of regions at large radii from M31, close to the Galactic plane. This latter limitation is now alleviated by the 3π Pan-STARRS1 survey, which could lead to the discovery of other distant Andromeda satellite dwarf galaxies.

A Hubble Space Telescope survey for novae in M87 - III. Are novae good standard candles 15 d after maximum brightness?

NASA Astrophysics Data System (ADS)

Shara, Michael M.; Doyle, Trisha F.; Pagnotta, Ashley; Garland, James T.; Lauer, Tod R.; Zurek, David; Baltz, Edward A.; Goerl, Ariel; Kovetz, Attay; Machac, Tamara; Madrid, Juan P.; Mikołajewska, Joanna; Neill, J. D.; Prialnik, Dina; Welch, D. L.; Yaron, Ofer

2018-02-01

Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle. Here, we demonstrate that a modified Buscombe-de Vaucouleurs hypothesis, namely that novae with decline times t2 > 10 d converge to nearly the same absolute magnitude about two weeks after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. For 13 novae with daily sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times t2 > 10 d we find that M87 novae display M606W,15 = -6.37 ± 0.46 and M814W,15 = -6.11 ± 0.43. If very fast novae with decline times t2 < 10 d are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1σ accuracies of ± 20 per cent with the above calibrations.

New Nova Candidates from the RSBE M31 Nova Survey

NASA Astrophysics Data System (ADS)

Lauber, Stephanie; Rector, Travis A.; Shafter, Allen W.

2015-01-01

Since 1995 the Kitt Peak National Observatory WIYN 0.9-m telescope has been used to monitor M31 for novae as part of the Research-Based Science Education Project (RBSE). The resulting images, which typically cover approximately the inner 20 arc min of M31, are taken through a broad-band H-alpha filter to isolate the strong H-alpha emission lines characteristic of novae shortly after eruption.We are in the process of reanalyzing the entire RBSE data set covering the period between September 1995 and August 2014 in order to produce an up-to-date list of novae from this survey. Here, we present coordinates and H-alpha magnitudes for 4 new nova discoveries not previous reported. Among the new nova discoveries, one system appears spatially coincident with M31N 1988-09a, and is thus a recurrent nova candidate.

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 2. Tessier, Francois. “ARAS Spectral Database - Nova-Del-2013” 22 Sep 2013 Web. 22 Sep 2013 3. Shore, Steven N. “Spectroscopy of Novae - A User’s Manual” arXiv:1211.3176 [astro-ph.SR] 14 Nov 2012

On the implications of the period distributions of subclasses of cataclysmic variables

NASA Astrophysics Data System (ADS)

Verbunt, Frank

1997-09-01

The period distributions of dwarf novae and nova-like variables above the period gap are different if the VY Scl systems are classed with the nova-like variables, but the same when the VY Scl phenomenon is classed with the dwarf nova outbursts. For the remaining nova-like variables, the period gap is no longer significant. Classification of the VY Scl phenomenon with dwarf novae suggests that dwarf nova outbursts are caused by variation in mass transfer from the donor. Absence of the period gap obviates the need for models explaining it, and invalidates one piece of evidence for the importance of magnetic braking for the evolution of cataclysmic variables and of low-mass binaries in general.

V1006 Cygni: Dwarf nova showing three types of outbursts and simulating some features of the WZ Sge-type behavior

NASA Astrophysics Data System (ADS)

Kato, Taichi; Pavlenko, Elena P.; Shchurova, Alisa V.; Sosnovskij, Aleksei A.; Babina, Julia V.; Baklanov, Aleksei V.; Shugarov, Sergey Yu.; Littlefield, Colin; Dubovsky, Pavol A.; Kudzej, Igor; Pickard, Roger D.; Isogai, Keisuke; Kimura, Mariko; de Miguel, Enrique; Tordai, Tamás; Chochol, Drahomir; Maeda, Yutaka; Cook, Lewis M.; Miller, Ian; Itoh, Hiroshi

2016-04-01

We observed the 2015 July-August long outburst of V1006 Cyg and established this object to be an SU UMa-type dwarf nova in the period gap. Our observations have confirmed that V1006 Cyg is the second established object showing three types of outbursts (normal, long normal, and superoutbursts) after TU Men. We have succeeded in recording the growing stage of superhumps (stage A superhumps) and obtained a mass ratio of 0.26-0.33, which is close to the stability limit of tidal instability. This identification of stage A superhumps demonstrates that superhumps indeed slowly grow in systems near the stability limit, the idea first introduced by Kato et al. (2014, PASJ, 66, 90). The superoutburst showed a temporary dip followed by a rebrightening. The moment of the dip coincided with the stage transition of superhumps, and we suggest that stage C superhumps are related to the start of the cooling wave in the accretion disk. We interpret that the tidal instability was not strong enough to maintain the disk in the hot state when the cooling wave started. We propose that the properties commonly seen in the extreme ends of mass ratios (WZ Sge-type objects and long-period systems) can be understood as a result of weak tidal effect.

MAXI/GSC detection of a new outburst from the black hole candidate H 1743-322

NASA Astrophysics Data System (ADS)

Shidatsu, M.; Nakahira, S.; Negoro, H.; Ueno, S.; Tomida, H.; Ishikawa, M.; Sugawara, Y.; Nakagawa, Y. E.; Mihara, T.; Sugizaki, M.; Serino, M.; Iwakiri, W.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Isobe, N.; Sugita, S.; Yoshii, T.; Tachibana, Y.; Ono, Y.; Fujiwara, T.; Harita, S.; Muraki, Y.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Kitaoka, Y.; Tsunemi, H.; Shomura, R.; Nakajima, M.; Tanaka, K.; Masumitsu, T.; Kawase, T.; Ueda, Y.; Kawamuro, T.; Hori, T.; Tanimoto, A.; Oda, S.; Tsuboi, Y.; Nakamura, Y.; Sasaki, R.; Yamauchi, M.; Furuya, K.; Yamaoka, K.

2016-11-01

The MAXI/GSC nova-alert system detected an X-ray brightening of the Galactic black hole candidate H 1743-322 in November 6, UT 03:01. The 2-20 keV flux increased from 12 +- 3 mCrab on November 4 (MJD 57696) to 37 +- 5 mCrab on November 6 (MJD 57698).

Ultraviolet studies of nova-like variables with the IUE

NASA Technical Reports Server (NTRS)

Guinan, E. F.

1983-01-01

KQ Mon is a new UX UMa-type nova-like variable. Optical spectra taken in 1978 reveal very shallow Balmer absorption lines and He I (wavelength 4471) absorption. There was no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42 degrees 14462 (=V3885 Sgr) and other members of the UX UMa class. KQ Mon was observed at low dispersion with the IUE satellite. Six spectra taken with the short wavelength prime (SWP) camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and A1 III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa-type objects, KQ Mon exhibits no emission lines or P Cygni-type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

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.

Novae in External Galaxies: M51, M87, and M101

NASA Astrophysics Data System (ADS)

Shafter, A. W.; Ciardullo, R.; Pritchet, C. J.

2000-02-01

As part of a program to determine the stellar population of novae, we have conducted a multiepoch Hα survey of the galaxies M51, M87, and M101. A total of nine and 12 novae were detected in the spiral galaxies M51 and M101, respectively, during four epochs of observation, and two epochs of observation yielded a total of nine novae in the giant elliptical galaxy M87. After correcting for the effective survey time and for the fraction of luminosity sampled, we find global nova rates of 18+/-7, 91+/-34, and 12+/-4 novae per year for M51, M87, and M101, respectively. After normalizing to the total K-band luminosity of each galaxy, we estimate luminosity-specific nova rates for M51, M87, and M101 of 1.09+/-0.47, 2.30+/-0.99, and 0.97+/-0.38 novae per year per 1010 solar luminosities in K. When we compare these data with measured values for the luminosity-specific nova rates of other galaxies, we find no compelling evidence for a significant variation with Hubble type. Possible ramifications of this result are discussed within the context of current theoretical models for nova production in galaxies.

The NOvA Technical Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayres, D.S.; Drake, G.R.; Goodman, M.C.

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 atmore » 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 design performance relative to the Design Criteria set out in Chapter 4. Chapter 7 presents the Work Breakdown Structure dictionary at Level 3 and the Milestone dictionary. Chapters 8 through 17 then take each Level 2 WBS element of the NOvA project and present each part of the design in more detail than the overview given in Chapter 5. Specific technical design criteria are delineated for each part of the project in addition to the scientific design criteria outlined in Chapter 4. Changes in the design since the NOvA CDR are discussed in detail. The work remaining to bring each part of this preliminary design to a final design is outlined. Appendix A is a guide to other NOvA Project documentation with links to those documents.« less

A Hubble Space Telescope survey for novae in M87 – III. Are novae good standard candles 15 d after maximum brightness?

DOE PAGES

Shara, Michael M.; Doyle, Trisha F.; Pagnotta, Ashley; ...

2017-11-16

Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle. Here in this paper, we demonstrate that a modified Buscombe–de Vaucouleurs hypothesis, namely that novae with decline times t2 > 10 d converge to nearly the same absolute magnitude about two weeksmore » after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. For 13 novae with daily sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times t 2 > 10 d we find that M87 novae display M606W,15 = -6.37 ± 0.46 and M814W,15 = -6.11 ± 0.43. If very fast novae with decline times t 2 < 10 d are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1σ accuracies of ± 20 percent with the above calibrations.« less

A Hubble Space Telescope survey for novae in M87 – III. Are novae good standard candles 15 d after maximum brightness?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shara, Michael M.; Doyle, Trisha F.; Pagnotta, Ashley

Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle. Here in this paper, we demonstrate that a modified Buscombe–de Vaucouleurs hypothesis, namely that novae with decline times t2 > 10 d converge to nearly the same absolute magnitude about two weeksmore » after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. For 13 novae with daily sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times t 2 > 10 d we find that M87 novae display M606W,15 = -6.37 ± 0.46 and M814W,15 = -6.11 ± 0.43. If very fast novae with decline times t 2 < 10 d are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1σ accuracies of ± 20 percent with the above calibrations.« less

Looking for Sterile Neutrinos via Neutral-Current Disappearance with NOvA

NASA Astrophysics Data System (ADS)

Yang, Shaokai; NOvA Collaboration

2017-01-01

Contradictory evidence has been presented on the issue of neutrino mixing between the three known active neutrinos and light sterile neutrinos. The excess of events as seen by the LSND and MiniBooNE experiments interpreted as short-baseline neutrino oscillations, the collective evidence of the reactor neutrino anomaly, and the gallium anomaly all point towards sterile neutrinos with mass at the 1 eV level. While these results are tantalizing, they are not conclusive as they are in tension with null results from other short-baseline experiments, and with disappearance searches in long-baseline and atmospheric experiments. Resolving the issue of the existence of light sterile neutrinos has profound implications for both particle physics and cosmology. The NOvA (NuMI Off-Axis νe Appearance) experiment may help clarify the situation by searching for disappearance of active neutrinos from the NuMI (Neutrinos from the Main Injector) beam over a baseline of 810 km. In this talk, we will describe a method of how NOvA can look for oscillations into sterile neutrinos, with focus on disappearance of neutral current (NC) neutrino events, will present the first analysis result of this search, discuss their implications in constraining the existence of light sterile neutrinos, and the planned updates to this analysis.

Dust, Abundances, and the Evolution of Novae

NASA Astrophysics Data System (ADS)

Woodward, Charles; Bode, Michael; Evans, Anuerin; Geballe, Thomas; Gehrz, Robert; Helton, Andrew; Krautter, Joachim; Lynch, David; Ness, Jan-Uwe; Rudy, Richard; Schwarz, Greg; Shore, Steve; Starrfield, Sumner; Truran, James; Vanlandingham, Karen; Wagner, R. Mark

2008-03-01

Evolved stars are the engines of energy production and chemical evolution in our Universe. They deposit radiative and mechanical energy into their environments. They enrich the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CNe) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. Our capstone study of 10 CNe will provide an ensemble of objects, well-populated in CNe parameter space (fast, slow, 'coronal', dusty) for detailed photoionization modeling and analysis. CNe are laboratories in which several poorly-understood astrophysical processes (e.g., mass transfer, thermonuclear runaway, optically thick winds, common envelope evolution, molecule and grain formation, coronal emission) may be observed. With Spitzer's unique wavelength coverage and point-source sensitivity we can: (i) investigate the in situ formation, astromineralogy, and processing of nova dust, (ii) determine the ejecta elemental abundances resulting from thermonuclear runaway, (iii) constrain the correlation of ejecta mass with progenitor type, (iv) measure the bolometric luminosity of the outburst, and (v) characterize the kinematics and structure of the ejected envelopes. Extensive ground-based and space-based (Chandra, Swift, XMM-Newton) programs led by team CoIs will complement Spitzer CNe observations.

Hydrogen burning of oxygen-17

NASA Astrophysics Data System (ADS)

Newton, Joseph

Classical novae are explosive binary systems involving the accretion of hydrogen rich material from a main sequence star onto the surface of a white dwarf partner, reaching peak temperatures of T = 0.1-0.4 GK. Observed elemental abundances from the ejecta provide much needed constraints for the modeling of these explosions. Novae are thought to be the most significant source of 15 N and 17 O in the universe. The 17 O(p,g) 18 F and 17 O(p,g) 14 N reactions have an important effect on nucleosynthesis in novae, since they determine the creation and destruction of 17 O and 18 F, which produces detectable g- radiation. The dominant contributor to the 17 O(p,g) 14 N reaction is a resonance at [Special characters omitted.] = 193 keV. The strength of this resonance has been measured and the results are presented. For the 17 O(p,g) 18 F reaction, the dominant contribution comes from the nonresonant direct capture process. The literature direct capture cross sections currently differ by a factor of two. This cross section has been measured in the current work and the results are also presented. New reaction rates have been calculated with these measured cross sections using a new Monte Carlo technique and these new rates have significantly reduced uncertainties compared to the current literature.

5 CFR 723.160 - Communications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED... PERSONNEL MANAGEMENT § 723.160 Communications. (a) The agency shall take appropriate steps to ensure... action that it can demonstrate would result in a fundamental alteration in the nature of a program or...

7 CFR 58.723 - Basis for selecting cheese for processing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Section 58.723 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT...

7 CFR 58.723 - Basis for selecting cheese for processing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Section 58.723 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT...

7 CFR 58.723 - Basis for selecting cheese for processing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Section 58.723 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT...

Watching a 'New Star' Make the Universe Dusty

NASA Astrophysics Data System (ADS)

2008-07-01

Using ESO's Very Large Telescope Interferometer, and its remarkable acuity, astronomers were able for the first time to witness the appearance of a shell of dusty gas around a star that had just erupted, and follow its evolution for more than 100 days. This provides the astronomers with a new way to estimate the distance of this object and obtain invaluable information on the operating mode of stellar vampires, dense stars that suck material from a companion. Uncovering the disc ESO PR Photo 22/08 Dust shells around a nova Although novae were first thought to be new stars appearing in the sky, hence their Latin name, they are now understood as signaling the brightening of a small, dense star. Novae occur in double star systems comprising a white dwarf - the end product of a solar-like star - and, generally, a low-mass normal star - a red dwarf. The two stars are so close together that the red dwarf cannot hold itself together and loses mass to its companion. Occasionally, the shell of matter that has fallen onto the ingesting star becomes unstable, leading to a thermonuclear explosion which makes the system brighter. Nova Scorpii 2007a (or V1280 Scorpii), was discovered by Japanese amateur astronomers on 4 February 2007 towards the constellation Scorpius ("the Scorpion"). For a few days, it became brighter and brighter, reaching its maximum on 17 February, to become one of the brightest novae of the last 35 years. At that time, it was easily visible with the unaided eye. Eleven days after reaching its maximum, astronomers witnessed the formation of dust around the object. Dust was present for more than 200 days, as the nova only slowly emerged from the smoke between October and November 2007. During these 200 days, the erupting source was screened out efficiently, becoming more than 10,000 times dimmer in the visual. An unprecedented high spatial resolution monitoring of the dust formation event was carried out with the Very Large Telescope Interferometer (VLTI), extending over more than 5 months following the discovery. The astronomers first used the AMBER near-infrared instrument, then, as the nova continued to produce dust at a high rate, they moved to using the MIDI mid-infrared instrument, that is more sensitive to the radiation of the hot dust. Similarly, as the nova became fainter, the astronomers switched from the 1.8-m Auxiliary Telescopes to their larger brethren, the 8.2-m Unit Telescopes. With the interferometry mode, the resolution obtained is equivalent to using a telescope with a size between 35 and 71 metres (the distance between the 2 telescopes used). The first observations, secured 23 days after the discovery, showed that the source was very compact, less than 1 thousandth of an arcsecond (1 milli-arcsecond or mas), which is a size comparable to viewing one grain of sand from about 100 kilometres away. A few days later, after the detection of the major dust formation event, the source measured 13 mas. "It is most likely that the latter size corresponds to the diameter of the dust shell in expansion, while the size previously measured was an upper limit of the erupting source," explains lead author Olivier Chesneau. Over the following months the dusty shell expanded regularly, at a rate close to 2 million km/h. "This is the first time that the dust shell of a nova is spatially resolved and its evolution traced starting from the onset of its formation up to the point that it becomes too diluted to be seen", says co-author Dipankar Banerjee, from India. The measurement of the angular expansion rate, together with the knowledge of the expansion velocity, enables the astronomer to derive the distance of the object, in this case about 5500 light-years. "This is a new and promising technique for providing distances of close novae. This was made possible because the state of the art facility of the VLTI, both in terms of infrastructure and management of the observations, allows one to schedule such observations," says co-author Markus Wittkowski from ESO. Moreover, the quality of the data provided by the VLTI was such that it was possible to estimate the daily production of dust and infer the total mass ejected. "Overall, V1280 Sco probably ejected more than the equivalent of 33 times the mass of the Earth, a rather impressive feat if one considers that this mass was ejected from a star not larger in radius than the Earth," concludes Chesneau. Of this material, about a percent or less was in the form of dust.

Separation and purification of astaxanthin from Phaffia rhodozyma by preparative high-speed counter-current chromatography.

PubMed

Du, Xiping; Dong, Congcong; Wang, Kai; Jiang, Zedong; Chen, Yanhong; Yang, Yuanfan; Chen, Feng; Ni, Hui

2016-09-01

An effective high-speed counter-current chromatography (HSCCC) method was established for the preparative isolation and purification of astaxanthin from Phaffia rhodozyma. With a two-phase solvent system composed of n-hexane-acetone-ethanol-water (1:1:1:1, v/v/v/v), 100mg crude extract of P. rhodozyma was separated to yield 20.6mg of astaxanthin at 92.0% purity. By further one step silica gel column chromatography, the purity reached 99.0%. The chemical structure of astaxanthin was confirmed by thin layer chromatography (TLC), UV spectroscopy scanning, high performance liquid chromatography with a ZORBAX SB-C18 column and a Waters Nova-pak C18 column, and ESI/MS/MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Combined Spectroscopic and Interferometric (NPOI) Observations of the Be Star o Cassiopeiae

DTIC Science & Technology

2010-01-01

velocidades radiales de la estrella o Cas de los espectros tomados entre 1992 y 2008 en Ondřejov y Dominion Astrophysical Observatory nos permitieron...orbitales de este sistema SB1 implican una función de masa muy alta de alrededor de una masa solar. Esto implica una masa muy alta de la estrella ...secundaria, posiblemente mayor que la de la estrella primaria. Para comprobar si hay la existencia de una secundaria tan masiva, o Cas fue observada con

A Twenty-Year Survey of Novae in M31

NASA Astrophysics Data System (ADS)

Crayton, Hannah; Rector, Travis A.; Walentosky, Matthew J.; Shafter, Allen W.; Lauber, Stephanie; Pilachowski, Catherine A.; RBSE Nova Search Team

2018-06-01

Numerous surveys of M31 in search of extragalactic novae have been completed over the last century, with a total of more than 1000 having been discovered during this time. From these surveys it has been estimated that the number of novae that occur in M31 is approximately 65 yr-1 (Darnley et al. 2006). A fraction of these are recurrent novae that recur on the timescales of years to decades (Shafter et al. 2015). From 1997 to 2017 we completed observations of M31 with the KPNO/WIYN 0.9-meter telescope, which offers a wide field of view suitable for surveying nearly all of the bulge and much of the disk of M31. Observations were completed in Hα so as to better detect novae in the bulge of the galaxy, where most novae reside. Our survey achieves a limiting absolute magnitude per epoch of MHα ∼ 7.5 mag, which prior M31 nova surveys in Hα (e.g., Ciardullo et al. 1987; Shafter & Irby 2001) have shown to be sufficiently deep to detect a typical nova several months after eruption. By completing nearly all of the observations with the same telescope, cameras, and filters we were able to obtain a remarkably consistent dataset.Our survey offers several benefits as compared to prior surveys. Nearly 200 epochs of observations were completed during the survey period. Observations were typically completed on a monthly basis; although on several occasions we completed weekly and nightly observations to search for novae with faster decay rates. Thus we were sensitive to most of the novae that erupted in M31 during the survey period.Over twenty years we detected 316 novae. Our survey found 85% of the novae in M31 that were reported by other surveys completed during the same time range and in the same survey area as ours (Pietsch et al. 2007). We also discovered 39 novae that were not found by other surveys. We present the complete catalog of novae from our survey, along with example light curves. Among other uses, our catalog will be useful for improving estimates of nova rate in M31. We also identify 72 standard stars within the survey area that will be useful for future surveys.

Sonification of Kepler Field SU UMa Cataclysmic Variable Stars V344 Lyr and V1504 Cyg

NASA Technical Reports Server (NTRS)

Tutchton, Roxanne M.; Wood, Matt A.; Still, Martin D.; Howell, Steve B.; Cannizzo, John K.; Smale, Alan P.

2012-01-01

Sonification is the conversion of quantitative data into sound. In this work we explain the methods used in the sonification of light curves provided by the Kepler instrument from Q2 through Q6 for the cataclysmic variable systems V344 Lyr and V1504 Cyg . Both systems are SU UMa stars showing dwarf nova outbursts and superoutbursts as well as positive and negative superhumps. Focused sonifications were done from average pulse shapes of each superhump, and separate sonifications of the full, residual light curves were done for both stars. The audio of these data reflected distinct patterns within the evolutions of supercycles and superhumps that matched pervious observations and proved to be effective aids in data analysis.

On the Nature of CP Pup

NASA Technical Reports Server (NTRS)

Mason, E.; Orio, M.; Mukai, K.; Bianchini, A.; deMartino, D.; diMille, F.; Williams, R. E.

2013-01-01

We present new X-ray and optical spectra of the old nova CP Pup (nova Pup 1942) obtained with Chandra and the CTIO 4m telescope. The X-ray spectrum reveals a multi-temperature optically thin plasma reaching a maximum temperature of 36+19 keV 16 absorbed by local complex neutral material. The time resolved optical spectroscopy confirms the presence of the 1.47 hr period, with cycle-to-cycle amplitude changes, as well as of an additional long term modulation which is suggestive either of a longer pe- riod or of non-Keplerian velocities in the emission line regions. These new observational facts add further support to CP Pup as a magnetic cataclysmic variable (mCV). We compare the mCV and the non-mCV scenarios and while we cannot conclude whether CP Pup is a long period system, all observational evidences point at an intermediate polar (IP) type CV.

Hubble COS Spectroscopy of the Dwarf Nova CW Mon: The White Dwarf in Quiescence?1

PubMed Central

Hause, Connor; Sion, Edward M.; Godon, Patrick; Boris, T. Gänsicke; Szkody, Paula; de Martino, Domitilla; Pala, Anna

2018-01-01

We present a synthetic spectral analysis of the HST COS spectrum of the U Geminorum-type dwarf nova CW Mon, taken during quiescence as part of our COS survey of accreting white dwarfs in Cataclysmic Variables. We use synthetic photosphere and optically thick accretion disk spectra to model the COS spectrum as well as archival IUE spectra obtained decades ago when the system was in an even deeper quiescent state. Assuming a reddening of E(B−V)=0.06, an inclination of 60° (CW Mon has eclipses of the accretion disk, and a white dwarf mass of 0.8M⊙, our results indicate the presence of a 22–27,000 K white dwarf and a low mass accretion rate (M˙≲10−10M⊙/yr), for a derived distance o ~200 to ~300 pc. PMID:29430023

Chemotaxonomy for naturally macerated tree-fern cuticles (Medullosales and Marattiales), Carboniferous Sydney and Mabou Sub-Basins, Nova Scotia, Canada

USGS Publications Warehouse

Zodrow, E.L.; Mastalerz, Maria

2001-01-01

Naturally macerated cuticles (NMC) and one synangium, representing medullosalean and marattialean tree-fern species, from two Carboniferous coalfields in Nova Scotia, Canada, are investigated. The samples were analyzed by infrared spectroscopy (FTIR), and by pyrolysis-gas chromatograph/mass spectrometry (py-Gc/Ms) techniques in search for chemical signatures that would help in developing a chemotaxonomic classification of Carboniferous fern species, assuming genetically dependent make-up of cuticles. FTIR-derived CH2/CH3 ratios, in conjunction with contributions from carboxyl groups, demonstrated a better potential for discriminating between medullosalean genera and species than molecular signatures obtained by py-Gc/Ms. However, the latter provided better data for differentiating medullosalean from marattialean tree ferns as a group. Changes in the chemical make-up of naturally macerated cuticles due to sample preparation are discussed. ?? 2001 Elsevier Science B.V. All rights reserved.

Superhumps in a Peculiar SU Ursae Majoris-Type Dwarf Nova, ER Ursae Majoris.

PubMed

Gao; Li; Wu; Zhang; Li

1999-12-10

We report the photometry of a peculiar SU Ursae Majoris-type dwarf nova, ER Ursae Majoris, for 10 nights during 1998 December and 1999 March, covering a complete rise to the supermaximum and a normal outburst cycle. Superhumps have been found during the rise to the superoutburst. A negative superhump appeared in the December 22 light curve, while the superhump on the next night became positive and had a large-amplitude waveform distinct from that of the previous night. In the normal outbursts we captured, superhumps with larger or smaller amplitudes seem to always exist, although it is not necessarily true for every normal outburst. These results show great resemblance to V1159 Ori. It is more likely that superhumps occasionally exist at essentially all phases of the eruption cycles of ER UMa stars, which should be considered in modeling.

BVRI Hα Photometric Evolution of Nova 2007 IN M 33

NASA Astrophysics Data System (ADS)

Munari, U.; Siviero, A.; Henden, A.; Dintinjana, B.; Mikuž, H.; Ochner, P.; Tomasoni, S.

The BVRCIC and Hα light curves of Nova 2007, located in the galaxy M 33, are presented. They display the fastest decline ever observed for a nova in this galaxy (Δ B = 0.40 ± 0.01 mag/day). Color indices of the nova match those of its counterparts in the Galaxy. The nova was discovered when it was already two magnitudes down from maximum (estimated to have occurred on September 13 at B = 15.5 mag).

Discovery of a New Photometric Sub-class of Faint and Fast Classical Novae

NASA Astrophysics Data System (ADS)

Kasliwal, M. M.; Cenko, S. B.; Kulkarni, S. R.; Ofek, E. O.; Quimby, R.; Rau, A.

2011-07-01

We present photometric and spectroscopic follow-up of a sample of extragalactic novae discovered by the Palomar 60 inch telescope during a search for "Fast Transients In Nearest Galaxies" (P60-FasTING). Designed as a fast cadence (1 day) and deep (g < 21 mag) survey, P60-FasTING was particularly sensitive to short-lived and faint optical transients. The P60-FasTING nova sample includes 10 novae in M 31, 6 in M 81, 3 in M 82, 1 in NGC 2403, and 1 in NGC 891. This significantly expands the known sample of extragalactic novae beyond the Local Group, including the first discoveries in a starburst environment. Surprisingly, our photometry shows that this sample is quite inconsistent with the canonical maximum-magnitude-rate-of-decline (MMRD) relation for classical novae. Furthermore, the spectra of the P60-FasTING sample are indistinguishable from classical novae. We suggest that we have uncovered a sub-class of faint and fast classical novae in a new phase space in luminosity-timescale of optical transients. Thus, novae span two orders of magnitude in both luminosity and time. Perhaps the MMRD, which is characterized only by the white dwarf mass, was an oversimplification. Nova physics appears to be characterized by a relatively rich four-dimensional parameter space in white dwarf mass, temperature, composition, and accretion rate.

Data handling with SAM and art at the NO vA experiment

DOE PAGES

Aurisano, A.; Backhouse, C.; Davies, G. S.; ...

2015-12-23

During operations, NOvA produces between 5,000 and 7,000 raw files per day with peaks in excess of 12,000. These files must be processed in several stages to produce fully calibrated and reconstructed analysis files. In addition, many simulated neutrino interactions must be produced and processed through the same stages as data. To accommodate the large volume of data and Monte Carlo, production must be possible both on the Fermilab grid and on off-site farms, such as the ones accessible through the Open Science Grid. To handle the challenge of cataloging these files and to facilitate their off-line processing, we havemore » adopted the SAM system developed at Fermilab. SAM indexes files according to metadata, keeps track of each file's physical locations, provides dataset management facilities, and facilitates data transfer to off-site grids. To integrate SAM with Fermilab's art software framework and the NOvA production workflow, we have developed methods to embed metadata into our configuration files, art files, and standalone ROOT files. A module in the art framework propagates the embedded information from configuration files into art files, and from input art files to output art files, allowing us to maintain a complete processing history within our files. Embedding metadata in configuration files also allows configuration files indexed in SAM to be used as inputs to Monte Carlo production jobs. Further, SAM keeps track of the input files used to create each output file. Parentage information enables the construction of self-draining datasets which have become the primary production paradigm used at NOvA. In this study we will present an overview of SAM at NOvA and how it has transformed the file production framework used by the experiment.« less

36 CFR 72.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AND RECREATION RECOVERY ACT OF 1978 General § 72.3 Definitions. As used in this part: Applicant... institutions, and (3) private organizations and individuals. In-kind contributions may consist of the value of... recognized Indian tribes. Participant: The grantee, or other agency or organization requesting and/or...

42 CFR 485.723 - Condition of participation: Physical environment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 5 2012-10-01 2012-10-01 false Condition of participation: Physical environment... Providers of Outpatient Physical Therapy and Speech-Language Pathology Services § 485.723 Condition of participation: Physical environment. The building housing the organization is constructed, equipped, and...

42 CFR 485.723 - Condition of participation: Physical environment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 5 2011-10-01 2011-10-01 false Condition of participation: Physical environment... Providers of Outpatient Physical Therapy and Speech-Language Pathology Services § 485.723 Condition of participation: Physical environment. The building housing the organization is constructed, equipped, and...

42 CFR 485.723 - Condition of participation: Physical environment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 5 2014-10-01 2014-10-01 false Condition of participation: Physical environment... Providers of Outpatient Physical Therapy and Speech-Language Pathology Services § 485.723 Condition of participation: Physical environment. The building housing the organization is constructed, equipped, and...

42 CFR 485.723 - Condition of participation: Physical environment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 5 2013-10-01 2013-10-01 false Condition of participation: Physical environment... Providers of Outpatient Physical Therapy and Speech-Language Pathology Services § 485.723 Condition of participation: Physical environment. The building housing the organization is constructed, equipped, and...

School Psychology in Nova Scotia

ERIC Educational Resources Information Center

King, Sara; McGonnell, Melissa; Noyes, Amira

2016-01-01

Registration as a psychologist in Nova Scotia can be at the master's or doctoral level; however, the Nova Scotia Board of Examiners in Psychology has announced a move to the doctoral degree as the entry-level to practice. Many school psychologists in Nova Scotia practice at the master's level; therefore, this change could affect school psychology…

When does an old nova become a dwarf nova? Kinematics and age of the nova shell of the dwarf nova AT Cancri

NASA Astrophysics Data System (ADS)

Shara, Michael M.; Drissen, Laurent; Martin, Thomas; Alarie, Alexandre; Stephenson, F. Richard

2017-02-01

The Z Cam-type dwarf nova AT Cancri (AT Cnc) displays a classical nova (CN) shell, demonstrating that mass transfer in cataclysmic binaries decreases substantially after a CN eruption. The hibernation scenario of cataclysmic binaries predicts such a decrease, on a time-scale of a few centuries. In order to measure the time since AT Cnc's last CN eruption, we have measured the radial velocities of a hundred clumps in its ejecta with SITELLE, Canada-France-Hawaii Telescope's recently commissioned imaging Fourier transform spectrometer. These range from -455 to +490 km s-1. Coupled with the known distance to AT Cnc of 460 pc, the size of AT Cnc's shell, and a simple model of nova ejecta deceleration, we determine that the last CN eruption of this system occurred 330_{-90}^{+135} yr ago. This is the most rapid transition from a high mass-transfer rate, nova-like variable to a low mass-transfer rate, dwarf nova yet measured, and in accord with the hibernation scenario of cataclysmic binaries. We conclude by noting the similarity in the deduced outburst date (within a century of 1686 CE) of AT Cnc to a `guest star' reported in the constellation Cancer by Korean observers in 1645 CE.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasliwal, M. M.; Kulkarni, S. R.; Ofek, E. O.

We present photometric and spectroscopic follow-up of a sample of extragalactic novae discovered by the Palomar 60 inch telescope during a search for 'Fast Transients In Nearest Galaxies' (P60-FasTING). Designed as a fast cadence (1 day) and deep (g < 21 mag) survey, P60-FasTING was particularly sensitive to short-lived and faint optical transients. The P60-FasTING nova sample includes 10 novae in M 31, 6 in M 81, 3 in M 82, 1 in NGC 2403, and 1 in NGC 891. This significantly expands the known sample of extragalactic novae beyond the Local Group, including the first discoveries in a starburstmore » environment. Surprisingly, our photometry shows that this sample is quite inconsistent with the canonical maximum-magnitude-rate-of-decline (MMRD) relation for classical novae. Furthermore, the spectra of the P60-FasTING sample are indistinguishable from classical novae. We suggest that we have uncovered a sub-class of faint and fast classical novae in a new phase space in luminosity-timescale of optical transients. Thus, novae span two orders of magnitude in both luminosity and time. Perhaps the MMRD, which is characterized only by the white dwarf mass, was an oversimplification. Nova physics appears to be characterized by a relatively rich four-dimensional parameter space in white dwarf mass, temperature, composition, and accretion rate.« less

A Search for Ultrafast Novae in M31

NASA Astrophysics Data System (ADS)

Sola, Nicole; Rector, Travis A.; Shafter, Allen W.; Horst, Chuck; Igarashi, Amy; Henze, Martin; Pilachowski, Catherine A.

2018-06-01

Numerous surveys in search of extragalactic novae have been completed over the last century. From Local Group surveys it has been estimated that the number of novae that occur in M31 is approximately 65 yr-1 (Darnley et al. 2006), with a total of more than 1000 having been discovered over the past century. A fraction of these are recurrent novae that recur on the timescales of years to decades (Shafter et al. 2015).Novae typically fade from view on timescales of weeks to months. However, Shara et al. (2017) present models that predict the existence of "ultrafast" novae that have two-magnitude decay times (t2) of less than a day. The remarkable recurrent nova M31N 2008-12a has a t2 time of ~2 days (e.g., Darnley et al. 2016). None faster than this have been seen in M31; however, most surveys of extragalactic novae use cadences of a day or longer, meaning such novae could be missed.In October 2017 we completed a two-week search for ultrafast novae in M31 with the WIYN 0.9m telescope. The telescope's Half-Degree Imager provided a field of view of a quarter square degree, which covers most of M31's bulge and part of the disk. Weather hampered observations on some nights, but for most nights we were able to obtain multiple observations of M31 on a near hourly basis. We present the results of our search.

49 CFR 192.723 - Distribution systems: Leakage surveys.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program...

49 CFR 192.723 - Distribution systems: Leakage surveys.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program...

49 CFR 192.723 - Distribution systems: Leakage surveys.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program...

49 CFR 192.723 - Distribution systems: Leakage surveys.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program...

49 CFR 192.723 - Distribution systems: Leakage surveys.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program...