Research Note

Swift observations of the March 2011 outburst of the cataclysmic variable NSV 1436: a probable dwarf nova

¹ Dept. of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
e-mail: julo@star.le.ac.uk
² American Association of Variable Star Observers, 49 Bay State Rd., Cambridge, MA 02138-1203, USA
³ XMM-Newton Science Operations Centre, ESAC, Apartado 78, 28691 Villanueva de la Cañada, Madrid, Spain
⁴ Astrophysics Research Institute, Liverpool John Moores University, Liverpool CH41 1 LDS, UK
⁵ American Astronomical Society  
⁶ School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404, USA
⁷ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
⁸ INTEGRAL Science Operations Centre, ESAC, Apartado 78, 28691 Villanueva de la Cañada, Madrid, Spain

Received: 15 April 2011
Accepted: 24 July 2011

Abstract

Aims. The March 2011 outburst of the poorly-studied cataclysmic variable NSV 1436 offered an opportunity to decide between dwarf nova and recurrent nova classifications.

Methods. We use seven daily observations in the X-ray and UV by the Swift satellite, together with AAVSO V photometry, to characterise the outburst and decline behaviour.

Results. The short optical outburst coincided with a faint and relatively soft X-ray state, whereas in decline to fainter optical magnitudes the X-ray source was harder and brighter. These attributes, and the modest optical outburst amplitude, indicate that this was a dwarf nova outburst and not a recurrent nova. The rapid optical fading suggests an orbital period below 2 h.