STRONG UV AND X-RAY VARIABILITY OF THE NARROW LINE SEYFERT 1 GALAXY WPVS 007-ON THE NATURE OF THE X-RAY LOW STATE

• Published in: The Astronomical journal Vol. 146; no. 4; pp. 1 - 19
• Main Authors: Grupe, Dirk, KOMOSSA, S, SCHARWACHTER, JULIA, Dietrich, Matthias, Leighly, Karen M, Lucy, Adrian, Barlow, Brad N
• Format: Journal Article
• Language: English
• Published: United States American Astronomical Society 01.10.2013
• Subjects: ABSORPTION; Astrophysics; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CLOUDS; COSMIC DUST; Covering; DENSITY; DETECTION; Displays; Dust; EMISSION; Flux; GALAXY NUCLEI; Physics; SEYFERT GALAXIES; Spectra; SPECTROSCOPY; WAVELENGTHS; X RADIATION; X-RAY SPECTRA; X-rays
• ISSN: 0004-6256; 1538-3881; 1538-3881
• DOI: 10.1088/0004-6256/146/4/78

We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS 1) galaxy WPVS 007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 x 10 super(23) cm super(-2) with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope alpha sub(UV), which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust "clouds" located beyond the dust sublimation radius of R sub(sub) approximately 20 lt-days.