Flash-ionization of pre-existing circumstellar material around Nova Oph 2015

Munari, U.; Walter, Frederick M.

doi:10.1093/mnrasl/slv146

Cited by 10 publications

(7 citation statements)

References 26 publications

(28 reference statements)

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“…Such narrow components have been observed in the early spectra of RSOphiuchi (Iijima 2009) and V407Cygni (Munari et al 2011;Shore et al 2011). However, this may not be exclusive to RG-novae because early narrow emission was also seen in the recent SG-nova candidate V2944Ophiuchi (Munari & Walter 2016). This interaction between the red giant wind and the ejecta can also produce shocks observable in the X-ray (Pottasch 1967;Bode et al 2006.…”

Section: Introductionmentioning

confidence: 99%

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

Williams

Darnley

Bode

et al. 2016

ApJ

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In our preceding paper, Liverpool Telescope data of M31 novae in eruption were used to facilitate a search for their progenitor systems within archival Hubble Space Telescope data, with the aim of detecting systems with red giant secondaries (RG-novae) or luminous accretion disks. From an input catalog of 38 spectroscopically confirmed novae with archival quiescent observations, likely progenitors were recovered for 11 systems. Here we present the results of the subsequent statistical analysis of the original survey, including possible biases associated with the survey and the M31 nova population in general. As part of this analysis, we examine the distribution of optical decline times (t 2 ) of M31 novae, how the likely bulge and disk nova distributions compare, and how the M31 t 2 distribution compares to that of the Milky Way. Using a detailed Monte Carlo simulation, we determine that 30 % 10 13 -+ of all M31 nova eruptions can be attributed to RG-nova systems, and at the 99% confidence level, 10% > of all M31 novae are RG-novae. This is the first estimate of a RG-nova rate of an entire galaxy. Our results also imply that RG-novae in M31 are more likely to be associated with the M31 disk population than the bulge; indeed, the results are consistent with all RG-novae residing in the disk. If this result is confirmed in other galaxies, it suggests that any Type Ia supernovae that originate from RG-nova systems are more likely to be associated with younger populations and may be rare in old stellar populations, such as early-type galaxies.

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Section: Introductionmentioning

confidence: 99%

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

Williams

Darnley

Bode

et al. 2016

ApJ

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“…Our calculation of the magnetic field strength is based on the best fitting gas density model from Orlando & Drake (2011). However, the gas density near the WD surface that Fermi-LAT assumed is about one order of magnitude higher than our model (Munari et al, 2010), and accordingly the magnetic field near the WD surface is 0.03G, which is much higher than our calculation for the same position (∼ 0.045 G). This magnetic field will result in a higher proton energy, as well as different profiles of the nova blast velocity.…”

Section: Particle Accelerationcontrasting

confidence: 77%

“…Cygni (Munari et al, 2010), which implies that the temporal evolution of its nova velocity is comparable with that of V407 Cygni. Sokoloski et al (2006) thereafter.…”

Section: Time Evolution Of the Novamentioning

confidence: 79%

“…The ANS collaboration in northern Italy obtained Hα spectra beginning on Mar.13 (+2.3d after the optical nova detection: Fig. 5.10), and measured the FWHM of the broad component of each spectrum (Munari et al, 2010). By treating the broad component of the spectral peaks as a result of the Doppler effect, we can see the temporal evolution on the ejecta velocity.…”

Section: Time Evolution Of the Novamentioning

confidence: 99%

“…10: Temporal evolution of the Hα spectra of V407 Cygni -The upper three plots in the left column are those in the quiescent phase (in the year 1999, 2008 and 2009), and the rest shows the evolution after the nova explosion (20100313=+2.3d and thereafter). Taken fromMunari et al (2010).…”

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confidence: 99%

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VERITAS observations of galactic gamma-ray sources

Tsurusaki¹

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The main topic of this thesis is analysis of an unidentified Galactic TeV gammaray source, MGRO J1908+06, discovered by Milagro instrument in 2007. We analyzed 54 hours of observational data from the Very Energetic Radiation Imaging Telescope Array System (VERITAS), a ground-based gamma-ray observatory in southern Arizona comprised of an array of four Cherenkov Telescopes that reconstructs the energy and direction of astrophysical gamma-rays by imaging Cherenkov light emitted by energetic particles in air showers produced by the primary gamma-rays. MGRO J1908+06 is located between a supernova remnant SNR G40.5-0.5 and a young, energetic pulsar PSR J1907+0602. We studied the energy dependent morphology of the TeV emission from the source and measured the source extent and spectrum. The source extends well past the boundary of the SNR and is not correlated with strong radio continuum or molecular line emission which likely excludes an origin for the emission as solely due to the SNR. While emission in the 0.5-1.25 TeV band was centered around the pulsar, higher energy emission was observed near the supernova remnant. This morphology is opposite that observed in other pulsar wind nebulae. We proposed two models for the high energy emission located well away from the pulsar but close to the SNR: (1) shock acceleration at the shock front created by an interaction between the pulsar wind and the dense gas at the edge of the SNR or (2) molecular clouds around the SNR provides seed photons with energies higher than those from Cosmic Microwave Backgrounds for inverse Compton scattering. The former model can be tested by looking for molecular emission lines that trace shocks and by measuring the pulsar velocity. In addition, we investigated the gamma-ray emission from the nova explosion of V407 Cygni that occurred in March 2010. The Fermi-LAT observed this event in the energy range of E >100 MeV. The origins of the gamma-ray emission that the Fermi-LAT team proposed are either protons (hadronic model) or electrons (leptonic Allured, Thomas Brantseg, Casey DeRoo and Scott Griffiths. Lastly, I would like to express my special thanks to my family in Japan for their never ending encouragement and support.

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Geometry of nova ejecta

et al. 2019

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We present photo-ionization and morpho-kinematic analyses of the ejecta of novae. The sample consists of ten novae belonging to the Fe II, He/N and hybrid classes. The Fe II class of novae in the sample have bipolar cone-like structures, with or without equatorial rings with inclination angle in the range of 40°–60°. The He/N novae have bullet-nose curve along with bipolar cone-like structures and equatorial rings with an inclination angle of ~80°. The hybrid nova in the sample is a bipolar frustum of prolate spheroid along with bipolar cone-like structures and equatorial rings with an inclination angle of 63°.

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Flash-ionization of pre-existing circumstellar material around Nova Oph 2015

Cited by 10 publications

References 26 publications

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

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

VERITAS observations of galactic gamma-ray sources

Geometry of nova ejecta

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