Alert Notice 646: VW Hyi in outburst and monitoring needed for multiwavelength campaign

August 6, 2018 : Further to AAVSO Alert Notice 640, the SU UMa-type dwarf nova VW Hyi is in outburst and is the subject of a multiwavelength campaign designed to detect possible radio emission during the outburst.

Numerous astronomers are carrying out research during this outburst, including Drs. Christian Knigge (University of Southampton), Diego Altamirano (University of Southampton), Patrick Woudt (University of Cape Town), David Buckley (South African Astronomical Observatory), Greg Sivakoff (University of Alberta), Deanne Coppejans (Northwestern University), James Miller-Jones (Curtin University), Elmar Koerding (Radboud University), Rob Fender (University of Oxford), Joe Patterson (Columbia University), Knox Long (Space Telescope Science Institute), and Koji Mukai (NASA Goddard Space Flight Center).

Target of opportunity observations have been triggered with multiple ground- and space-based resources, including the MeerKAT radio telescope, ATCA radio telescope array, Chandra, Swift, and SALT.

Optical observations indicating and confirming that VW Hyi was going into outburst - used by the astronomers to trigger the various resources - were contributed by AAVSO observers. Many observers have been monitoring VW Hyi, watching for it to go into outburst; cameras of the AAVSOnet robotic network have also been monitoring VW Hyi for this campaign.

Recent observations submitted to the AAVSO include (for photometry runs, observations are representative and include first and last observations in run):
2018 Jul 31.83381 UT, 13.267 V +/-0.017 (G. Myers, Hillsborough, CA);
Jul 31.83461, 13.231 V +/-0.019 (Myers);
Aug. 02.95833, <13.2 (F. Feijo, Canela, Brazil);
05.54650, 12.889 V +/-0.007 (P. Nelson, Ellinbank, VIC, Australia);
05.58178, 12.629 V +/-0.006 (Nelson);
05.58689, 12.563 V +/-0.006 (Nelson);
05.61476, 12.491 V +/-0.023 (Myers);
05.61876, 12.468 V +/-0.023 (Myers);
05.67942, 12.082 V +/-0.064 (Myers);
05.99653, 9.7 (Feijo);
06.28925, 9.434 V +/-0.006 (F.-J. Hambsch, Mol, Belgium);
06.32458, 9.421 B +/-0.005 (Hambsch);
06.36682, 9.428 V +/-0.005 (Hambsch);
06.40312, 9.445 B +/-0.004 (Hambsch);

B and R or B and V photometry is requested. If high-quality U observations can be obtained, they would be very valuable. Time series observations are requested while VW Hyi is in outburst. Visual observations are also welcome.

Please continue your observations until after VW Hyi has returned to minimum, and then until the end of August, in order to provide good context for the outburst and for correlation with the multiwavelength data.

Coordinates:  R.A. 04 09 11.28   Dec. -71 17 41.4   (from VSX)

Charts with comparison star sequences for VW Hyi may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name VW HYI.

AAVSO Forums: This campaign is the topic of the AAVSO Campaigns and Observation Reports forum thread

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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