Benvenuti nell'Anagrafe della Ricerca d'Ateneo
La valutazione delle attività di ricerca che si svolgono nelle università ha assunto un'importanza rilevante sia per l'intero sistema universitario sia all'interno di ogni singolo ateneo. Roma Tre si è quindi dotata di idonei strumenti informativi in grado di supportare al meglio le azioni di monitoraggio e di valutazione delle attività di ricerca svolte nei propri dipartimentied ha realizzato una Anagrafe della Ricerca di Ateneo.
EnglishThe X-ray bright PG quasar PG 1440+356 (Mkn 478) was observed four times across 13 months with the XMM-Newton observatory. Flux variations with a dynamical range of a factor about 6 were observed in both the soft (E < 1 keV) and the hard (E > 3 keV) X-ray band. However, large spectral variations are observed in the latter band only. We suggest that the X-ray emission in this object is due to Comptonization of kT similar or equal to 60 eV disk photons by a 20-50 keV plasma with a complex density structure. Analysis of the harmonic content of Mkn 478 light curves unveils a characteristic timescale similar to1 day, common to both energy bands. A longer (similar tomonths) timescale is detected in the soft X-ray band only.
| Titolo: | Timescales trips to PG quasars: The Mkn 478 case |
| Autori: | |
| Data di pubblicazione: | 2004 |
| Rivista: | |
| Abstract: | The X-ray bright PG quasar PG 1440+356 (Mkn 478) was observed four times across 13 months with the XMM-Newton observatory. Flux variations with a dynamical range of a factor about 6 were observed in both the soft (E < 1 keV) and the hard (E > 3 keV) X-ray band. However, large spectral variations are observed in the latter band only. We suggest that the X-ray emission in this object is due to Comptonization of kT similar or equal to 60 eV disk photons by a 20-50 keV plasma with a complex density structure. Analysis of the harmonic content of Mkn 478 light curves unveils a characteristic timescale similar to1 day, common to both energy bands. A longer (similar tomonths) timescale is detected in the soft X-ray band only. |
| Handle: | http://hdl.handle.net/11590/132540 |
| Appare nelle tipologie: | 1.1 Articolo in rivista |
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