A swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory
A swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory
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 (1.26 × 10−12 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 …