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| Query : 2003MNRAS.342..422M |
2003MNRAS.342..422M - Mon. Not. R. Astron. Soc., 342, 422-426 (2003/June-3)
Changing look: from Compton-thick to Compton-thin, or the rebirth of fossil active galactic nuclei.
MATT G., GUAINAZZI M. and MAIOLINO R.
Abstract (from CDS):
We discuss the properties of a small sample of type 2 Seyfert galaxies whose X-ray spectra changed appearance on time-scales of years, becoming reflection-dominated from Compton-thin, or vice versa. A reflection-dominated spectrum is usually taken as evidence of Compton-thick absorption, but we instead argue that such a spectrum is due to a temporary switching-off of the nuclear radiation. The observations discussed here may help to explain mismatches between optical and X-ray classifications, and provide new strong and direct evidence for the presence of more than one cold circumnuclear region in type 2 Seyfert galaxies.
Abstract Copyright: 2003 RAS
Journal keyword(s): galaxies: active - galaxies: Seyfert - X-rays: galaxies
Simbad objects: 9
| Number of rows : 9 |
| N | Identifier | Otype |
ICRS (J2000) RA |
ICRS (J2000) DEC |
Mag U | Mag B | Mag V | Mag R | Mag I | Sp type |
#ref
1850 - 2026 |
#notes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | M 77 | Sy2 | 02 42 40.7091669408 | -00 00 47.859690204 | 9.70 | 9.61 | 8.87 | 10.1 | 9.9 | ~ | 4897 | 2 |
| 2 | NGC 1365 | Sy1 | 03 33 36.458 | -36 08 26.37 | 10.48 | 10.08 | 9.63 | 8.79 | 9.7 | ~ | 1987 | 2 |
| 3 | Z 31-36 | Sy2 | 08 04 05.8608218112 | +05 06 49.823376120 | 14.55 | 13.7 | ~ | 340 | 2 | |||
| 4 | NGC 2992 | Sy2 | 09 45 42.045 | -14 19 34.90 | 13.54 | 13.14 | 12.18 | 12.6 | 12.2 | ~ | 951 | 3 |
| 5 | NGC 4051 | Sy1 | 12 03 09.6101337312 | +44 31 52.682601288 | 11.08 | 12.92 | 9.94 | ~ | 2270 | 1 | ||
| 6 | NGC 4945 | Sy2 | 13 05 27.279 | -49 28 04.44 | 9.31 | 14.40 | 7.55 | ~ | 1582 | 2 | ||
| 7 | NGC 5506 | Bla | 14 13 14.8761010056 | -03 12 27.556909272 | 15.25 | 14.38 | ~ | 1173 | 1 | |||
| 8 | NGC 6240 | Sy2 | 16 52 58.9 | +02 24 03 | 14.31 | 13.37 | ~ | 1734 | 2 | |||
| 9 | NGC 6300 | Sy2 | 17 16 59.5418094960 | -62 49 13.946588832 | 10.88 | 13.08 | 9.44 | 10.2 | ~ | 478 | 1 |
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