Abstract
We present near-IR (NIR) and optical observations of the Type Ic supernova (SN Ic) SN 2020oi in the galaxy M100 and the broad-lined SN Ic SN 2020bvc in UGC 9379, using Gemini, Las Cumbres ...Observatory, Southern Astrophysical Telescope, and other ground-based telescopes. The NIR spectrum of SN 2020oi at day 63 since the explosion shows strong CO emissions and a rising
K
-band continuum, which is the first unambiguous dust detection from an SN Ic. Non-LTE CO modeling shows that CO is still optically thick and that the lower limit to the CO mass is 10
−3
M
⊙
. The dust temperature is 810 K, and the dust mass is ∼10
−5
M
⊙
. We explore the possibilities that the dust is freshly formed in the ejecta, heated dust in the preexisting circumstellar medium, and an infrared echo. The light curves of SN 2020oi are consistent with a STELLA model with canonical explosion energy, 0.07
M
⊙
Ni mass, and 0.7
M
⊙
ejecta mass. A model of high explosion energy of 10
52
erg, 0.4
M
⊙
Ni mass, and 6.5
M
⊙
ejecta mass with the circumstellar matter reproduces the double-peaked light curves of SN 2020bvc. We observe temporal changes of absorption features of the IR Ca
ii
triplet, S
i
at 1.043
μ
m, and Fe
ii
at 5169 Å. The blueshifted lines indicate high velocities, up to 60,000 km s
−1
for SN 2020bvc and 20,000 km s
−1
for SN 2020oi, and the expansion velocity rapidly declines before the optical maximum. We present modeled spectral signatures and diagnostics of CO and SiO molecular bands between 1.4 and 10
μ
m.
In this manuscript, we report the outcome of the topical workshop:
paving the way to alternative NNLO strategies
(
https://indico.ific.uv.es/e/WorkStop-ThinkStart_3.0
), by presenting a discussion ...about different frameworks to perform precise higher-order computations for high-energy physics. These approaches implement novel strategies to deal with infrared and ultraviolet singularities in quantum field theories. A special emphasis is devoted to the local cancellation of these singularities, which can enhance the efficiency of computations and lead to discover novel mathematical properties in quantum field theories.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The origin of dust in the early universe has been the subject of considerable debate. Core-collapse supernovae (ccSNe), which occur several million years after their massive progenitors form, could ...be a major source of that dust, as in the local universe several ccSNe have been observed to be copious dust producers. Here we report nine near-infrared (0.8-2.5 m) spectra, obtained with GNIRS on Gemini North, of the Type II-P supernova (SN) 2017eaw in NGC 6946, spanning the time interval 22-205 days after discovery. The spectra show the onset of CO formation and continuum emission at wavelengths greater than 2.1 m from newly formed hot dust, in addition to numerous lines of hydrogen and metals, which reveal the change in ionization as the density of much of the ejecta decreases. The observed CO masses estimated from a local thermodynamic equilibrium (LTE) model are typically 10−4 M during days 124-205, but could be an order of magnitude larger if non-LTE conditions are present in the emitting region. The timing of the appearance of CO is remarkably consistent with the chemically controlled dust models of Sarangi & Cherchneff.
Abstract
SN 2014J in M 82 is the closest Type Ia supernova (SN Ia) in decades. The proximity allows for detailed studies of supernova physics and provides insights into the circumstellar and ...interstellar environment. In this work, we analyse Spitzer mid-infrared (mid-IR) data of SN 2014J in the 3.6 and 4.5 μm wavelength range, together with several other nearby and well-studied SNe Ia. We compile the first composite mid-IR light-curve templates from our sample of SNe Ia, spanning the range from before peak brightness well into the nebular phase. Our observations indicate that SNe Ia form a very homogeneous class of objects at these wavelengths. Using the low-reddening supernovae for comparison, we constrain possible thermal emission from circumstellar dust around the highly reddened SN 2014J. We also study SNe 2006X and 2007le, where the presence of matter in the circumstellar environment has been suggested. No significant mid-IR excess is detected, allowing us to place upper limits on the amount of pre-existing dust in the circumstellar environment. For SN 2014J, M
dust ≲ 10− 5 M⊙ within r
dust ∼ 1017 cm, which is insufficient to account for the observed extinction. Similar limits are obtained for SNe 2006X and 2007le.
We present 5-28 m SOFIA FORECAST spectroscopy complemented by panchromatic X-ray through infrared observations of the CO nova V5668 Sgr documenting the formation and destruction of dust during ∼500 ...days following outburst. Dust condensation commenced by 82 days after outburst at a temperature of ∼1090 K. The condensation temperature indicates that the condensate was amorphous carbon. There was a gradual decrease of the grain size and dust mass during the recovery phase. Absolute parameter values given here are for an assumed distance of 1.2 kpc. We conclude that the maximum mass of dust produced was 1.2 × 10−7 M if the dust was amorphous carbon. The average grain radius grew to a maximum of ∼2.9 m at a temperature of ∼720 K around day 113 when the shell visual optical depth was τv ∼ 5.4. Maximum grain growth was followed by a period of grain destruction. X-rays were detected with Swift from day 95 to beyond day 500. The Swift X-ray count rate due to the hot white dwarf peaked around day 220, when its spectrum was that of a kT = 35 eV blackbody. The temperature, together with the supersoft X-ray turn-on and turn-off times, suggests a white dwarf mass of ∼1.1 M . We show that the X-ray fluence was sufficient to destroy the dust. Our data show that the post-dust event X-ray brightening is not due to dust destruction, which certainly occurred, as the dust is optically thin to X-rays.
V445 Puppis: Dustier than a Thousand Novae Banerjee, D. P. K.; Evans, A.; Woodward, C. E. ...
Astrophysical journal. Letters,
08/2023, Letnik:
952, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract
V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter ...from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this context, this study estimates the dust and ejecta masses in the 2000 November eruption of V445 Pup. Subsequent to its outburst, the star became cocooned in a dust envelope. An analysis of the spectral energy distribution (SED) of the dust using infrared data shows that V445 Pup produced at least 10
−3
M
⊙
of dust, which is unprecedented for a classical or recurrent nova. The SED can be explained by a combination of a cold dust component at 105 ± 10 K, mass (1.9 ± 0.8) × 10
−3
M
⊙
, and a warm dust component at 255 ± 10 K, mass (2.2 ± 1.2) × 10
−5
M
⊙
. For a conservative choice of the gas-to-dust mass ratio in the range 10–100, the mass of the ejecta is 0.01–0.1
M
⊙
. Such a high mass range raises the question: why did V445 Pup not detonate as a Type Ia SN as is predicted in certain double-detonation sub-Chandrasekhar supernovae formalisms? We reexamine the nature of V445 Pup and discuss its role as a potential SN progenitor.
Near-IR (NIR) spectroscopy is presented for Nova Scorpii 2014. It is shown that the outburst occurred in a symbiotic binary system – an extremely rare configuration for a classical nova outburst to ...occur in but appropriate for the eruption of a recurrent nova of the T CrB class. We estimate the spectral class of secondary as M5III ± (two sub-classes). The maximum magnitude versus rate of decline relations give an unacceptably large value of 37.5 kpc for the distance. The spectra are typical of the He/N class of novae with strong He i and H lines. The profiles are broad and flat topped with full width at zero intensities approaching 9000–10 000 km s−1 and also have a sharp narrow component superposed which is attributable to emission from the giant's wind. Hot shocked gas, accompanied by X-rays and γ-rays, is expected to form when the high-velocity ejecta from the nova ploughs into the surrounding giant wind. Although X-ray emission was observed no γ-ray emission was reported. It is also puzzling that no signature of a decelerating shock is seen in the NIR, seen in similar systems like RS Oph, V745 Sco and V407 Cyg, as rapid narrowing of the line profiles. The small outburst amplitude and the giant secondary strongly suggest that Nova Sco 2014 could be a recurrent nova.
Abstract
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.
Abstract
We present a detailed study of the 2019 outburst of the cataclysmic variable V1047 Cen, which hosted a classical nova eruption in 2005. The peculiar outburst occurred 14 yr after the ...classical nova event and lasted for more than 400 days, reaching an amplitude of around 6 magnitudes in the optical. Early spectral follow-up revealed what could be a dwarf nova (accretion disk instability) outburst. However, the outburst duration, high-velocity (>2000 km s
−1
) features in the optical line profiles, luminous optical emission, and presence of prominent long-lasting radio emission together suggest a phenomenon more exotic and energetic than a dwarf nova outburst. The outburst amplitude, radiated energy, and spectral evolution are also not consistent with a classical nova eruption. There are similarities between V1047 Cen’s 2019 outburst and those of classical symbiotic stars, but pre-2005 images of the field of V1047 Cen indicate that the system likely hosts a dwarf companion, implying a typical cataclysmic variable system. Based on our multiwavelength observations, we suggest that the outburst may have started with a brightening of the disk due to enhanced mass transfer or disk instability, possibly leading to enhanced nuclear shell burning on the white dwarf, which was already experiencing some level of quasi-steady shell burning. This eventually led to the generation of a wind and/or bipolar, collimated outflows. The 2019 outburst of V1047 Cen appears to be unique, and nothing similar has been observed in a typical cataclysmic variable system before, hinting at a potentially new astrophysical phenomenon.
ABSTRACT
We present infrared spectroscopy of the 2019 eruption of the recurrent nova V3890 Sgr, obtained over the period of 5.1–46.3 d after the eruption. The spectrum of the red giant became more ...prominent as the flux declined, and by day 46.3 dominated the spectrum. Hydrogen and helium emission lines consisted of a narrow component superposed on a broad pedestal. The full width at half-maximum of the narrow components declined with time t as the eruption progressed, as t−0.74, whereas those of the broad components remained essentially constant. Conversely, the line fluxes of the narrow components of Pa β remained roughly constant, while those of the broad components declined by a factor ∼30 over a period of ≲ 25 d. The behaviour of the broad components is consistent with them arising in unencumbered fast-flowing ejecta perpendicular to the binary plane, in material that was ejected in a short ∼3.3-d burst. The narrow components arise in material that encounters the accumulated circumstellar material. The outburst spectra were rich in coronal lines. There were two coronal line phases, one that originated in gas ionized by supersoft X-ray source, the other in shocked gas. From the relative fluxes of silicon and sulphur coronal lines on day 23.4 – when the emitting gas was shocked – we deduce that the temperature of the coronal gas was 9.3 × 105 K, and that the abundances are approximately solar.
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