2017MNRAS.469.4236Z -
Mon. Not. R. Astron. Soc., 469, 4236-4248 (2017/August-3)
Multiwavelength monitoring of a very active dwarf nova AX J1549.8-5416 with an unusually high duty cycle.
ZHANG G., GELFAND J.D., RUSSELL D.M., LEWIS F., MASETTI N., BERNARDINI F., ANDRUCHOW I. and ZIBECCHI L.
Abstract (from CDS):
We present the results of our analysis of new optical, ultraviolet (UV) and X-ray observations of a highly variable source - AX J1549.8-5416. Both the detection of several fast rise, exponential decay outbursts in the optical light curve and the lack of He II emission lines in the optical spectra suggest AX J1549.8-5416 is a cataclysmic variable of the dwarf nova (DN) type. The multiwavelength analysis of three mini-outbursts and one normal outburst represent one of the most complete multiwavelength studies of a DN and help to refine the relationship between the X-ray, UV and optical emission in this system. We find that the UV emission is delayed with respect to the optical by 1.0-5.4 d during the rising phase of the outburst. The X-ray emission is suppressed during the peak of the optical outburst and recovers during the end of the outburst. From our analysis of archival Swift, Chandra and XMM-Newton observations of AX J1549.8-5416, we estimate this DN has a high duty cycle (∼50 per cent), suggesting a quiescent X-ray luminosity larger than 1032 erg s–1. We also find the X-ray and UV flux are roughly anticorrelated. Furthermore, we find that, at low X-ray fluxes, the X-ray spectrum is well described by a single temperature thermal plasma model, while at high X-ray fluxes, an isobaric cooling flow model also works. We find that the maximum temperature of the plasma in quiescence is significantly higher than that in outburst.
Abstract Copyright:
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
stars: dwarf novae - stars: individual: AX J1549.8-5416 - X-rays: binaries - X-rays: binaries
Status at CDS
:
Large table(s) will be appraised for possible ingestion in VizieR.
CDS comments:
LTT 6284 is a probable misprint for LTT 6248.
Simbad objects:
7
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