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We report our photometric and spectroscopic follow-up observations of the superoutbursts of three dwarf novae (GWAC,180415A, GWAC,181017A and GWAC,181211A) identified independently by the Ground Wide-angle Cameras system, one of the ground-based instruments of the China-France SVOM mission. Based on a combination of our photometry and that taken from the AAVSO, our period analysis of the superhumps enables us to determine the mass ratios to be 0.0967-0.1163, 0.1879-0.1883 and 0.0981-0.1173 for GWAC,180415A, GWAC,181017A and GWAC,181211A, respectively. GWAC,180415A can be firmly identified as a WZ sge-type dwarf novae due to its long duration ($sim2$ weeks) multiple rebrightenings with amplitudes of 3-4 magnitudes, the early superhump associated with a double-wave modulation and the low mass ratio. The inferred low mass ratio and location in the $varepsilon-P_{mathrm{orb}}$ diagram suggest that GWAC,181211A is a WZ sge-type dwarf novae candidate. The measured Balmer decrements suggest the Balmer line emission is produced from an optical thick region in GWAC,180415A and GWAC,181017A, and from an optical thin region in GWAC,181211A.
We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at Okayama Observatory of Kyoto University and through VSNET collaboration. Our spectroscopic observatio
We present phase-resolved spectroscopy, photometry and circular spectropolarimetry of the eclipsing polar UZ Fornacis. Doppler tomography of the strongest emission lines using the inside-out projection revealed the presence of three emission regions:
In this paper, we report the detection and follow-ups of a super stellar flare GWAC,181229A with an amplitude of $Delta Rsim$9.5 mag on a M9 type star by $text{SVOM/GWAC}$ and the dedicated follow-up telescopes. The estimated bolometric energy $E_{bo
We present the SVOM (Space-based multi-band astronomical Variable Objects Monitor) mission that the Chinese National Space Agency and the French Space Agency have decided to jointly implement. SVOM has been designed to detect all known types of gamma
Symbiotic binaries are systems containing white dwarfs (WDs) and red giants. Symbiotic novae are those systems in which thermonuclear eruptions occur on the WD components. These are to be distinguished from events driven by accretion disk instabiliti