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The Fermi LAT discovery that classical novae produce >100 MeV gamma-rays establishes that shocks and relativistic particle acceleration are key features of these events. These shocks are likely to be radiative due to the high densities of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Brian D. Metzger , Thomas Finzell , Indrek Vurm , Romain Hascoet , Andrei M. Beloborodov , Laura Chomiuk

Classical novae are important producers of radioactive nuclei, such as be7, n13, f18, na22 and al26. The disintegration of these nuclei produces positrons (except for be7) that through annihilation with electrons produce photons of energies…

Astrophysics · Physics 2016-08-15 J. Gómez-Gomar , M. Hernanz , J. José , J. Isern

We critically examine the recent claimed detection of Raman scattered O VI at around 6830\AA\ in the iron curtain stage spectra of the classical CO nova V339 Del. The observed line variations are compatible in profile and timing of emission…

Solar and Stellar Astrophysics · Physics 2014-10-15 Steven N. Shore , Ivan De Gennaro Aquino , Simone Scaringi , Hans van Winckel

We present results of our dense spectroscopic monitoring of Nova V5668 Sgr. Starting on March 19 in 2015, only a few days after discovery, we have obtained a series of spectra with the TIGRE telescope and its HEROS echelle spectrograph…

We present near infrared spectroscopy of Nova Herculis 2021 (V1674 Her), obtained over the first 70 days of its evolution. This fastest nova on record displays a rich emission line spectrum, including strong coronal line emission with…

Solar and Stellar Astrophysics · Physics 2021-11-24 C. E. Woodward , D. P. K. Banerjee , T. R. Geballe , K. L. Page , S. Starrfield , R. M. Wagner

Classical novae emit gamma-ray radiation at 511 keV and below, with a cut-off at around (20-30) keV, related to positron annihilation and its Comptonization in the expanding envelope. This emission has been elusive up to now, because it…

Astrophysics · Physics 2009-10-31 M. Hernanz , J. Jose , A. Coc , J. Gomez-Gomar , J. Isern

In the last few years the Fermi-LAT instrument has detected GeV gamma-ray emission from several novae. Such GeV emission can be interpreted in terms of inverse Compton emission from electrons accelerated in the shock or in terms of emission…

High Energy Astrophysical Phenomena · Physics 2019-08-15 R. López-Coto , J. Sitarek , W. Bednarek , E. de Ona Wilhelmi , R. Desiante , F. Longo , E. Hays

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 ~10^(-4) solar masses of material at…

We report on Chandra X-ray observations of SN 2016jae and SN 2018cqj, both low luminosity Type Ia supernova that showed the presence of a H line in their early optical spectrum. No X-ray emission is detected at the location of either SN.…

High Energy Astrophysical Phenomena · Physics 2024-07-02 Vikram V. Dwarkadas

In the last few years the Fermi -LAT instrument has detected GeV gamma-ray emission from a few novae. Such GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. It is expected that…

High Energy Astrophysical Phenomena · Physics 2019-08-15 J. Sitarek , W. Bednarek , R. Lopez-Coto , E. de Ona Wilhelmi

In recent years, several nova explosions have been detected by Fermi/LAT at E>100 MeV, mainly early after the explosion and for a short period of time. The first evidence of particle acceleration in novae was found in the 2006 eruption of…

High Energy Astrophysical Phenomena · Physics 2019-10-22 Laura Delgado , Margarita Hernanz

Superluminous supernovae (SLSNe) are a new class of transients with luminosities $\sim10 -100$ times larger than the usual core-collapse supernovae (SNe). Their origin is still unclear and one widely discussed scenario involves a…

High Energy Astrophysical Phenomena · Physics 2026-01-23 Shang Li , Yun-Feng Liang , Neng-Hui Liao , Lei Lei , Yi-Zhong Fan

The radio light curves of novae rise and fall over the course of months to years, allowing for detailed observations of the evolution of the nova shell. However, the main parameter determined by radio models of nova explosions - the mass of…

Classical novae are runaway thermonuclear burning events on the surfaces of accreting white dwarfs in close binary star systems, sometimes appearing as new naked-eye sources in the night sky. The standard model of novae predicts that their…

This paper reports on the $\gamma$-ray properties of the 2018 Galactic nova V392 Per, spanning photon energies $\sim$0.1 GeV to 100 TeV by combining observations from the Fermi Gamma-ray Space Telescope and the HAWC Observatory. In one of…

We conducted a target of opportunity X-ray observation of the classical nova V458 Vulpeculae 88 days after the explosion using the Suzaku satellite. With a 20 ks exposure, the X-ray Imaging Spectrometer detected X-ray emission significantly…

Astrophysics · Physics 2015-05-13 Masahiro Tsujimoto , Dai Takei , Jeremy J. Drake , Jan-Uwe Ness , Shunji Kitamoto

Eruptions of classical novae are possible sources of lithium formation and gamma-ray emission. Nova remnants can also become Type Ia supernovae (SNe Ia). The contribution of novae to these phenomena depends on nova rates, which are not well…

A lot of information concerning the mechanism of nova explosions will be extracted from the possible future observations with INTEGRAL. In order to be prepared for this task, we are performing detailed models of the gamma-ray emission of…

Astrophysics · Physics 2007-05-23 M. Hernanz , J. Gomez-Gomar , J. Jose , A. Coc , J. Isern

The evolution of the luminosity of nova shells in the century following the nova outburst is studied for the lines H-alpha, H-beta, and [O III]. About 1200 flux measurements from 96 objects have been collected from the literature, from…

Astrophysics · Physics 2007-05-23 Ronald A. Downes , Hilmar W. Duerbeck , Catherine E. Delahodde

Synoptic spectroscopic observations of the U Sco 2010 outburst from maximum light to quiescence as well as a contemporaneous X-ray observation are presented and analyzed. The X-ray spectrum 52 days after outburst indicates a hot source…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. P. Diaz , R. E. Williams , G. J. Luna , M. Moraes , L. Takeda