X-ray emission from narrow-line Seyfert 1 galaxies with extreme narrow broad line width Yanli Ai Yunnan Astronomical Observatory Weimin Yuan ( Yunnan Astronomical Observatory ) Stefanie komossa ( Max Planck Institute for Extraterrestrial Physics ). Narrow Line Seyfert 1 (NLS1).
X-ray emission from narrow-line Seyfert 1 galaxies with extreme narrow broad line width
Yunnan Astronomical Observatory
Weimin Yuan (Yunnan Astronomical Observatory)
Stefanie komossa (Max Planck Institute for Extraterrestrial Physics)
A special class of broad-line AGN
Accreting close to the Eddington rate L/LEdd~1 possible via slim disk, c.f. standard disk
(e.g. Abramowicz + ‘88; Wang J.-M. + ‘99, Mineshige + ’00)
Balmer lines broader than forbidden lines (observable BLR) but narrower than normal type I AGN (fwhm < 2000km/s)
Zhou et al. 2006 selected ~ 2000 NLS1s from SDSS
Break down at ~ 1000 km/s
Γ - FWHM (Hβ) anti-correlation
important in AGN correlation space (Eigenvector 1 )
ROSAT photon index
X-ray properties of these NSL1s with extreme narrow Balmer line width is interesting !
Soft X-ray excess emission
NLS1s + Sy1s
Zhou et al . 2006
Estimated from hardness ratio
spectral model assumption
Boller et al .1996
Detailed X-ray analysis needed !
Steeper Soft X-ray spectrum is caused by stronger soft excess emissionobserved kT > maximum standard accretion disk KT Cannot be explained by the thermal emission from the standard accretion diskquestion: where does SXE come from?
Crummy et al. 2006
from Done + 2007
optically thin gas
Czerny & Elvis ‘87, Wandel & Petrosian ‘88, Shimura & Takahara ‘95
Ross & Fabian’05,
Crummy + ’06
Done + et al. ‘06
Atomic opacity in E~0.7-3keV
OVII/VIII, Fe L-shell absorption edges
Sample selection1) FWHM (Hβ) < 1200km/s from 2,000 NLS1s in Zhou et al (2006)2) matched with ROSAT PSPC and 2XMM with radius of 30" and 5" respectively.3) requiring X-ray counts > 200 for spectral analysisconsist of 20 NLS1s, having 12 observations in XMM and 13 in ROSATProperties :1) typical NLS1s in optical 2) small balck hole masses (three IMBH candidates in Greene & Ho, 2004)3) high Eddington ratio4) all are radio-quiet except SDSS J1633+4718 with radio loudness of 2.13
Result of soft X-ray spectral fittingstrong intrinsic absorption have not been detectedOur result confirm the break down of Γ - FWHM(Hβ) relation in Zhou et al. (2006)
Soft excess temperature distribution1) higher than expected maximum standard accretion disc temperature2) in 100 - 200 eV, similar to that in much more massive PG quasar
Soft X-ray excess strength distributionsoft excess strength does not increase with decrease of line width .possible explanation for break down : soft excess saturates at FWHM around 1000 km/s
(but not strong enough, not blurred)
either an additional emission component or disk reflection dominated
Example: SDSS J0940+0324
0.34 KeV Γ=1.99 chi^2 = 274.4 (273dof)
Example: SDSS J2299+0107
Blurred disk refl.
Power-law + BB
R_in=2.2Rg extreme !
chi^2 = 293 (293 d.o.f.)
1). In spectral analysis of 20 NSL1s we confirmed our result in Zhou et al. (2006) that soft X-ray photon indices and the broad optical emission line widths break down at FWHM (Hβ) around 1000km/s. saturation of the relative strength of soft excesss at narrow line width as one possible explanation.
2). thermal temperature of excess in 100 - 200eV, quite same with much more massive radio-quiet QSOs. Significantly higher than the maximum accretion disk temperature
3). SXE may have different origins.
Comptonization can reproduce soft excess feature in five NLS1s with relatively low Eddington ratio ( < 0.5);
blurred ionized disc reflection model well reproduce the XMM spectra in three NLS1s with high Edd. ratio. Our result suggest the origin may be dependent on Edd. Ratio ( ~ 1.0 )