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 x 10-(12) erg cm(-2) s(-1)) was about 20 times fainter than its historical average value, and remained steady along the whole observation (similar to 2.3 d). The observed flat spectrum (Gamma similar or equal to 0.8) and intense iron line (EW similar or equal to 600 eV) are best explained by assuming that the active nucleus has switched off, leaving only a residual reflection component visible.

Guainazzi, M., Nicastro, F., Fiore, F., Matt, G., Mchardy, I., Orr, A., et al. (1998). A swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory RID C-3235-2011. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 301(1), L1-L4 [10.1046/j.1365-8711.1998.02089.x].

A swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory RID C-3235-2011

MATT, Giorgio;
1998-01-01

Abstract

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 x 10-(12) erg cm(-2) s(-1)) was about 20 times fainter than its historical average value, and remained steady along the whole observation (similar to 2.3 d). The observed flat spectrum (Gamma similar or equal to 0.8) and intense iron line (EW similar or equal to 600 eV) are best explained by assuming that the active nucleus has switched off, leaving only a residual reflection component visible.
1998
Guainazzi, M., Nicastro, F., Fiore, F., Matt, G., Mchardy, I., Orr, A., et al. (1998). A swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory RID C-3235-2011. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 301(1), L1-L4 [10.1046/j.1365-8711.1998.02089.x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/121942
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