The Stony Brook/SMARTS Atlas of (mostly) Southern Novae

Walter, Frederick M.; Battisti, Andrew; Towers, S.; Bond, Howard E.; Stringfellow, Guy S.

doi:10.1086/668404

Cited by 106 publications

(129 citation statements)

References 44 publications

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“…For the radio flare to have been due to freely expanding ejecta with T ∼ 10 4 K, the emitting material would have had to have been ejected not at the start of the eruption, but more than 26 days after t 0 . Neither the optical spectra (Walter et al 2012) nor the optical light curve (Mróz et al 2015), however, show evidence for a strong new outflow a month into the eruption. Furthermore, the contrast between the fairly constant X-ray emission measure, EM x , and the rapidly rising radio flux between 46.2 and 62.3 days after the start of the eruption further supports our contention that the radio flare was not thermal emission from shock-heated gas.…”

Section: Evidence For Non-thermal Emissionmentioning

confidence: 95%

“…The first VLA observation, however, produced a non-detection at 33 GHz, with a 3σ upper limit of 0.08 mJy on day 2.4 (MJD 56040.4), suggesting that the fast flow did not start before t 0 . Because the 4,000 km s −1 flow was clearly evident in optical spectra on day 2.0 (Buil 2012) and day 2.4 (Walter et al 2012), it must therefore have started between t 0 (day 0) and day 2.…”

Section: Radio Emissionmentioning

confidence: 99%

“…V5589 Sgr was classified as a fast 'hybrid' nova, with Fe II emission on day 3 and He/N features by day 8 (Esipov et al 2012;Walter et al 2012;Williams 2012). The rapidly evolving, complex profiles of the emission lines in the optical spectra from SMARTS 1 http://www.astro.sunysb.edu/fwalter/SMARTS/NovaAtlas/ reveal that the ejecta were most likely aspherical and that they consisted of multiple flows.…”

Section: Introductionmentioning

confidence: 99%

“…V5589 Sgr is not a known Fermi/LAT γ-ray source: it is not in the 3FGL catalogue (Acero Figure 1. Hα line profiles from selected SMARTS optical spectra of V5589 Sgr, colourized to show days after t 0 = MJD 56038.0 (Walter et al 2012). The spectra are normalized to the 6300-6400 Å continuum, and are minimally smoothed with a Fourier filter to minimize high frequency noise.…”

Section: Introductionmentioning

confidence: 99%

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Shock-powered radio emission from V5589 Sagittarii (Nova Sgr 2012 #1)

Weston

Sokoloski

Chomiuk

et al. 2016

Mon. Not. R. Astron. Soc.

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Since the Fermi discovery of γ-rays from novae, one of the biggest questions in the field has been how novae generate such high-energy emission. Shocks must be a fundamental ingredient. Six months of radio observations of the 2012 nova V5589 Sgr with the VLA and 15 weeks of X-ray observations with Swift/XRT show that the radio emission consisted of: 1) a shock-powered, non-thermal flare; and 2) weak thermal emission from 10 −5 M of freely expanding, photoionized ejecta. Absorption features in the optical spectrum and the peak optical brightness suggest that V5589 Sgr lies 4 kpc away (3.2-4.6 kpc). The shock-powered flare dominated the radio light curve at low frequencies before day 100. The spectral evolution of the radio flare, its high radio brightness temperature, the presence of unusually hard (kT x > 33 keV) X-rays, and the ratio of radio to X-ray flux near radio maximum all support the conclusions that the flare was shock-powered and non-thermal. Unlike most other novae with strong shock-powered radio emission, V5589 Sgr is not embedded in the wind of a redgiant companion. Based on the similar inclinations and optical line profiles of V5589 Sgr and V959 Mon, we propose that shocks in V5589 Sgr formed from collisions between a slow flow with an equatorial density enhancement and a subsequent faster flow. We speculate that the relatively high speed and low mass of the ejecta led to the unusual radio emission from V5589 Sgr, and perhaps also to the non-detection of γ-rays.

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Section: Evidence For Non-thermal Emissionmentioning

confidence: 95%

Section: Radio Emissionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Shock-powered radio emission from V5589 Sagittarii (Nova Sgr 2012 #1)

Weston

Sokoloski

Chomiuk

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The near-infrared JHK magnitudes are from Mt. Abu observations (see Table 2) and SMARTS/CTIO 1.5m telescope facility (Walter et al, 2012). The epochs of Mount Abu Infrared observations are marked by vertical dashes on the light curve.…”

Section: Optical and Near-infrared Lightcurvesmentioning

confidence: 99%

Near-infrared studies of V5558 Sgr: an unusually slow nova with multiple outbursts

Das

Banerjee

Nandi

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present near-infrared (1-2.5 µm) JHK photo-spectroscopic results of the unusually slow nova V5558 Sgr (2007). V5558 Sgr showed a slow climb to maximum that lasted for about 60 days and then underwent at least five strong secondary outbursts. We have analyzed the optical light curve to derive large t 2 and t 3 values of 281 ± 3 and 473 ± 3 days respectively. An alternate approach is adopted to derive a distance estimate of 1.55 ± 0.25 kpc as conventional MMRD relation may not be applicable for a slow nova. In the pre-maxima stage the spectra showed narrow (FWHM ∼ 400 -550 km s −1 ) and strong emission lines of Paschen and Brackett series with prominent P-Cygni components. In the later phase the spectra show significant changes with the development of strong and broad (∼ 1000 km s −1 ) emission lines of HI, HeI, OI, and NI and some uncommon Fe II emission lines. No evidence of dust formation is seen. V5558 Sgr has been shown to be a rare hybrid nova showing a transition from He/N to Fe II type from optical spectra. However the near-infrared data do not show such a transition and we discuss this anomalous behavior. A recombination analysis of the Brackett lines allows us to constrain the electron density and emission measure during the early optically thick phase and to estimate the mass of the ejecta to be (6.0 ± 1.5) × 10 −4 M ⊙ , assuming a filling factor of unity, from later observations.

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