PHL 1092 as a transient extreme X-ray weak quasar
نویسندگان
چکیده
منابع مشابه
PHL 1092 as a transient extreme X–ray weak quasar
We report a dramatic variability event in the X–ray history of the Narrow–Line quasar PHL 1092 (z = 0.396). Our latest 2008 XMM–Newton observation reveals a flux drop of ∼ 200 with respect to the previous observation performed about 4.5 years earlier, and a drop of ∼ 135 with respect to its historical flux. Despite the huge X–ray variation, the UV flux remains constant producing a very signific...
متن کاملROSAT HRI monitoring of extreme X - ray variability in the narrow - line quasar PHL 1092
We report results from an 18-day ROSAT HRI monitoring campaign on the ultrasoft Narrow-Line Seyfert 1 (NLS1) class quasar PHL 1092. This luminous, radio-quiet quasar showed strong X-ray variability in a short ROSAT PSPC observation, and ROSAT HRI monitoring of the similar object IRAS 13224–3809 revealed extreme variability on intermediate timescales. We wanted to determine whether remarkable X-...
متن کاملExtreme X - ray variability in the luminous quasar PDS 456
We present evidence from BeppoSAX and XMM-Newton of extreme X-ray variability in the high luminosity radio-quiet quasar PDS 456, the most luminous known AGN at z < 0.3. Repeated X-ray flaring is found in PDS 456, over the duration of the 340 ksec long BeppoSAX observation. The X-ray flux doubles in just 30 ksec, whilst the total energy output of the flaring events is as high as 10 51 erg. Under...
متن کاملStrong X-ray Absorption in a Broad Absorption Line Quasar: Phl 5200
We present ASCA observations of the z 5 1.98 prototype broad absorption line quasar (BALQSO): PHL 5200. The source was detected in both SIS and GIS. A power-law spectrum (aE 5 0.620.6 10.9 ) with large intrinsic absorption (NH 5 1.321.1 12.3 3 10 cm) best describes the spectrum. Excess column density over the local Galactic value is required at the 99% confidence level. This detection suggests ...
متن کاملAn intense soft - excess and evidence for light bending in the luminous narrow - line quasar PHL 1092
The narrow-line quasar PHL 1092 was observed by XMM-Newton at two epochs separated by nearly thirty months. Timing analyses confirm the extreme variability observed during previous X-ray missions. A measurement of the radiative efficiency is in excess of what is expected from a Schwarzschild black hole. In addition to the rapid X-ray variability, the short UV light curves (< 4 hours) obtained w...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society: Letters
سال: 2009
ISSN: 1745-3925,1745-3933
DOI: 10.1111/j.1745-3933.2009.00669.x