On 1998 May 9-11, BeppoSAX observed the low-luminosity Seyfert 1 galaxy NGC 4051 in an ultra-dim X-ray state. The 2-10 keV flux (1.26x10^-12 erg cm^-2 s^-1) was about 20 times fainter than its historical average value, and remained steady along the whole observation (~2.3 d). The observed flat spectrum (Gamma~=0.8) and intense iron line (EW~=600 eV) are best explained by assuming that the active nucleus has switched off, leaving only a residual reflection component visible.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 1998
- GALAXIES: INDIVIDUAL: NGC 4051;
- GALAXIES: SEYFERT;
- X-RAYS: GALAXIES;
- 5 pages, Latex, 3 Postscript figures, accepted for publication in MNRAS