Second Timescale Photometry of the Very Fast Nova V1674 Her with Palomar Gattini-IR

Hansen, Kylie Y.; De, Kishalay; Ashley, M. C. B.; Kasliwal, Mansi M.; Delacroix, Alexander; Greffe, Tim; Hale, David; Hankins, Matthew J.; Lau, Ryan M.; Li, Cheng-Kui; McKenna, D.; Moore, Anna; Ofek, E. O.; Smith, Roger M.; Soon, J.; Soria, Roberto; Srinivasaragavan, Gokul P.; Travouillon, Tony

doi:10.3847/2515-5172/ac3256

Cited by 3 publications

(1 citation statement)

References 3 publications

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“…Depending on the relative masses of the accretion disc and nova ejecta, the accretion disc may survive the eruption or be completely swept away (Drake & Orlando 2010;Figueira et al 2018). The periodic variations were missing in both optical and X-ray bands near the nova peak (Hansen et al 2021), either as a result of temporarily arrested accretion or due to the expanded photosphere engulfing the binary system outshining and obscuring the effects of accretion. The orbital and spin modulations emerged in the optical band on day 4 and day 12 after the eruption, respectively (Patterson et al 2022).…”

Section: Shock Locationmentioning

confidence: 99%

The multi-wavelength view of shocks in the fastest nova V1674 Her

Sokolovsky,

Johnson,

Buson

et al. 2023

Preprint

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Classical novae are shock-powered multi-wavelength transients triggered by a thermonuclear runaway on an accreting white dwarf. V1674 Her is the fastest nova ever recorded (time to declined by two magnitudes is 2 = 1.1 d) that challenges our understanding of shock formation in novae. We investigate the physical mechanisms behind nova emission from GeV -rays to cm-band radio using coordinated Fermi-LAT, NuSTAR, Swift and VLA observations supported by optical photometry. Fermi-LAT detected short-lived (18 h) 0.1-100 GeV emission from V1674 Her that appeared 6 h after the eruption began; this was at a level of (1.6 ± 0.4) × 10 −6 photons cm −2 s −1 . Eleven days later, simultaneous NuSTAR and Swift X-ray observations revealed optically thin thermal plasma shock-heated to k shock = 4 keV. The lack of a detectable 6.7 keV Fe K emission suggests supersolar CNO abundances. The radio emission from V1674 Her was consistent with thermal emission at early times and synchrotron at late times. The radio spectrum steeply rising with frequency may be a result of either free-free absorption of synchrotron and thermal emission by unshocked outer regions of the nova shell or the Razin-Tsytovich effect attenuating synchrotron emission in dense plasma. The development of the shock inside the ejecta is unaffected by the extraordinarily rapid evolution and the intermediate polar host of this nova.

show abstract

Section: Shock Locationmentioning

confidence: 99%

The multi-wavelength view of shocks in the fastest nova V1674 Her

Sokolovsky,

Johnson,

Buson

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

Soft X-ray and FUV observations of Nova Her 2021 (V1674 Her) with AstroSat

Bhargava,

Dewangan,

Anupama

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Nova Her 2021 or V1674 Her was one of the fastest novae to be observed so far. We report here the results from our timing and spectral studies of the source observed at multiple epochs with AstroSat. We report the detection of a periodicity in the source in soft X-rays at a period of 501.4–501.5 s which was detected with high significance after the peak of the super-soft phase, but was not detected in the far ultraviolet (FUV) band of AstroSat. The shape of the phase-folded X-ray light curves has varied significantly as the nova evolved. The phase-resolved spectral studies reveal the likely presence of various absorption features in the soft X-ray band of 0.5–2 keV, and suggest that the optical depth of these absorption features may be marginally dependent on the pulse phase. Strong emission lines from Si, N and O are detected in the FUV, and their strength declined continuously as the nova evolved and went through a bright X-ray state.

show abstract

The multiwavelength view of shocks in the fastest nova V1674 Her

Sokolovsky

Johnson

Buson

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Classical novae are shock-powered multi-wavelength transients triggered by a thermonuclear runaway on an accreting white dwarf. V1674 Her is the fastest nova ever recorded (time to declined by two magnitudes is t2 = 1.1 d) that challenges our understanding of shock formation in novae. We investigate the physical mechanisms behind nova emission from GeV γ-rays to cm-band radio using coordinated Fermi-LAT, NuSTAR, Swift and VLA observations supported by optical photometry. Fermi-LAT detected short-lived (18 h) 0.1-100 GeV emission from V1674 Her that appeared 6 h after the eruption began; this was at a level of (1.6 ± 0.4) × 10−6 photons cm−2 s−1. Eleven days later, simultaneous NuSTAR and Swift X-ray observations revealed optically thin thermal plasma shock-heated to kTshock = 4 keV. The lack of a detectable 6.7 keV Fe Kα emission suggests super-solar CNO abundances. The radio emission from V1674 Her was consistent with thermal emission at early times and synchrotron at late times. The radio spectrum steeply rising with frequency may be a result of either free-free absorption of synchrotron and thermal emission by unshocked outer regions of the nova shell or the Razin-Tsytovich effect attenuating synchrotron emission in dense plasma. The development of the shock inside the ejecta is unaffected by the extraordinarily rapid evolution and the intermediate polar host of this nova.

show abstract

Second Timescale Photometry of the Very Fast Nova V1674 Her with Palomar Gattini-IR

Cited by 3 publications

References 3 publications

The multi-wavelength view of shocks in the fastest nova V1674 Her

The multi-wavelength view of shocks in the fastest nova V1674 Her

Soft X-ray and FUV observations of Nova Her 2021 (V1674 Her) with AstroSat

The multiwavelength view of shocks in the fastest nova V1674 Her

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