The ANS Collaboration Monitoring Program

Munari, U.; Bacci, S.; Baldinelli, L.; Castellani, F.; Cetrulo, G.; Cherini, G.; Dallaporta, S.; Dallavia, G.; Englaro, A.; Frigo, A.; Graziani, M.; Luppi, V.; Maitan, A.; Marangoni, C.; Milani, and Albert; Moretti, Stefano; Moschini, F.; Ochner, P.; Siviero, A.; Righetti, G. L.; Tomaselli, S.; Tomasoni, S.; Vagnozzi, A.; Valisa, P.

doi:10.1515/astro-2017-0353

Cited by 44 publications

(57 citation statements)

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“…Tarasova & Shakhovskoi (2013) reported that the spectral energy distribution (SED) of their pre-maximum spectrum, taken on Aug. 15.8, was similar to a late-A or early-F-type spectrum. The line spectrum, which was dominated by P Cyg-type hydrogen lines with a pronounced absorption component (see Shore et al 2013a;Tomov et al 2013;Tarasova 2013;Munari et al 2013b), also suggested that the effective temperature of the envelope probably is 10 4 K. During Aug. 19, observed a significant weakening of the H i absorption components, while those of the Fe ii, He i, and O i profiles were still clearly present. This evolution indicated a distinctive cooling of the expanding envelope.…”

Section: Introductionmentioning

confidence: 93%

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

Skopal

Drechsel

Тарасова

et al. 2014

A&A

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Aims. We determine the temporal evolution of the luminosity (L WD ), radius (R WD ) and effective temperature (T eff ) 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), UBVR C I C 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), T eff was in the range of 6000-12 000 K, R WD was expanding non-uniformly in time from ∼66 to ∼300 (d/3 kpc) R , and L WD was super-Eddington, but not constant. Its maximum of ∼9 × 10 38 (d/3 kpc) 2 erg s −1 occurred around Aug. 16.0, at the maximum of T eff , half a day before the visual maximum. After the fireball stage, a large emission measure of 1.0−2.0×10 62 (d/3 kpc) 2 cm −3 constrained the lower limit of L WD 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, > ∼ 10 5 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.

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Section: Introductionmentioning

confidence: 93%

“…Magnitudes were converted to fluxes according to the calibration of Henden & Kaitchuck (1982). Observations were dereddened with E B−V = 0.18 (Munari et al 2013b;Shore et al 2013c;Chochol et al 2014) by using the extinction curve of Cardelli et al (1989). Then we scaled the dereddened spectra to the V flux-point.…”

Section: Observationsmentioning

confidence: 99%

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

Skopal

Drechsel

Тарасова

et al. 2014

A&A

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“…Absolute spectroscopy of KT Eri was obtained during the outburst as part of the long-term ANS Collaboration monitoring of novae in eruption (see Munari et al 2012). We used the Varese 0.61m telescope equipped with the mark.II Multi Mode A&A 564, A76 (2014) Spectrograph (Munari & Valisa 2014), that allows rapid switching between low-dispersion, medium-dispersion and Echelle high-resolution modes.…”

Section: Observationsmentioning

confidence: 99%

The narrow and moving HeII lines in nova KT Eridani

Munari

Mason

Valisa³

2014

A&A

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We present outburst and quiescence spectra of the classical nova KT Eri and discuss the appearance of a sharp HeII 4686 Å emission line, whose origin is a matter of discussion for those novae that showed a similar component. We suggest that the sharp HeII line, when it first appeared toward the end of the outburst optically thick phase, comes from the wrist of the dumbbell structure characterizing the ejecta. When the ejecta turned optically thin, the already sharp HeII line became two times narrower and originated from the exposed central binary. During the optically thin phase, the HeII line displayed a large change in radial velocity that had no counterpart in the Balmer lines (both their narrow cores and the broad pedestals). The large variability in radial velocity of the HeII line continued well into quiescence, and it remains the strongest emission line observed over the whole optical range.

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“…Their respective first peaks were 3.6 and 4.1 mag, making them the visually brightest novae observed since V382 Vel 1999 (2.5 mag peak) and since the 2008 launch of Fermi (V339 Del 2013 peaked at 4.5 mag; see Munari et al 2015). V5668 Sgr was characterized by systematically longer timescales in its brightening and fading (see Figure 1 for an overview, and Table 1).…”

Section: Introductionmentioning

confidence: 98%

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

Cheung

Jean

Shore

et al. 2016

ApJ

108

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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 longerduration 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.

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The ANS Collaboration Monitoring Program

Abstract: ANS Collaboration is a growing Italian network of small and medium size telescopes performing spectroscopy (low and medium resolution single dispersion, and Echelle high resolution modes) and UBV R

Cited by 44 publications

References 4 publications

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

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

The narrow and moving HeII lines in nova KT Eridani

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

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