Spectroscopic Observations of WZ Sge-type Dwarf Novae, GW Lib and V455 And in Superoutburst

TL;DR

This study presents comprehensive spectroscopic observations of two WZ Sge-type dwarf novae during their superoutbursts, revealing high-velocity winds and dynamic accretion disk phenomena.

Contribution

It provides the first detailed spectroscopic analysis of GW Lib and V455 And throughout their superoutbursts, highlighting wind speeds and disk evolution.

Findings

Detection of winds with speeds around 1000 km/s during the rising phase.

Evidence of disk flaring and temperature inversion layer emergence.

Spectroscopic evolution of hydrogen, helium, and carbon lines.

Abstract

We carried out intensive spectroscopic observations of two WZ Sge-type dwarf novae, GW Lib, and V455 And during their superoutbursts in 2007, at 6 observatories. The observations covered the whole of both superoutbursts from the very maximum to the fading tail. We found evidence of the winds having a speed of $\sim$1000 km s$^{-1}$ which blew in GW Lib during the rising phase. The evolution of the hydrogen, helium, and carbon lines suggests flaring of the accretion disk and emergence of the temperature inversion layer on the disk.