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On the geometry of broad emission region in quasars Roberto Decarli Turin - May, 20 th, 2008 Università degli Studi dell’Insubria Dipartimento di Fisica.

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Presentation on theme: "On the geometry of broad emission region in quasars Roberto Decarli Turin - May, 20 th, 2008 Università degli Studi dell’Insubria Dipartimento di Fisica."— Presentation transcript:

1 On the geometry of broad emission region in quasars Roberto Decarli Turin - May, 20 th, 2008 Università degli Studi dell’Insubria Dipartimento di Fisica e Matematica Dottorato in Astronomia e Astrofisica M. Labita A. Treves R. Falomo

2 Bettoni et al., 2003 Supermassive Black Holes and their host galaxies Massive BHs are found in all massive spheroids (Kormendy & Richstone, 1995) M BH depends on the luminosity, mass, stellar velocity dispersion of the host spheroid. R inf ≈ GM BH / * 2 ~0.002 R spheroid A joint evolution of the BH and the spheroid took place. Independent measures of M BH and the host galaxy properties are needed.

3 Virial determination of M BH In Type-1 AGNs, the emission lines from gas at R~0.01-0.5 pc are observed (« R inf !!). Gas emission lines are Doppler broadened (> 1000 km/s). Reverberation mapping proved that the gas motion is mainly gravitational R BLR = A (L ) 0.7 (Kaspi et al., 2000) v BLR = f · FWHM From the host galaxy luminosity: log M BH =-0.50 M R - 2.60 (Bettoni et al., 2003)

4 The geometrical factor f f is a function of the adopted BLR dynamical model: –Isotropic model: f =√3 /2 (fixed). Broad line shape: gaussian. –Thin disk model: f =1/(2 sin ). Broad line shape: depend on the (unknown) radial mass distribution. –Thick disk model: f =1/(2 c 1 sin + 2 c 2 / √3). c 1 and c 2 depend on and disk H/R. Broad line shape: unconstrained at high values of ; gaussian at small. Line of sight Line of sight

5 The sample Low redshift (z<0.6) quasars with: –images in the HST-WFPC2 archive and published values of the luminosity of the host galaxies –at least 1 spectrum from the HST-FOS archive, from the SDSS or from on-purpose observations at the Asiago 1.82m Telescope. 49 targets. 16 of them have both optical and UV spectra. Asiago SDSS HST-FOS 16 13 20 Optical spectra: 36 objects UV spectra: 29 objects Tot.: 49

6 The FUV-to-V spectrum of low-z QSOs Decarli et al (2008) Labita et al (2006)

7 H and C IV broad lines From R BLR - L relations: R BLR (H  ) ≈ 1.5 R BLR (C IV ) Comparing the FWHMs: FWHM (H  ) is NOT correlated with FWHM (C IV ) From the FWHM/  line ratio: H  and C IV fill different regions of the FWHM/  line plane, H  being closer to the Gaussian case Decarli et al (2008)

8 Virial Products and M BH We compare the VPs with the M BH as estimated from the host galaxy luminosity. The CIV-based VPs are well correlated with M BH. H  data show a significantly worse spread.

9 f and the line width Pieces of evidence supporting a flat BLR in radio loud quasars: the FWHM-R c-l dependence f is found to depend on the line width! The isotropic model predict f = const, while the dependence on the line width is consistent with a disk-like scenario. The f -FWHM dependence is observed both for radio loud and radio quiet quasars.

10 A sketch of the BLR geometry We suggest that: –an isotropic model of the BLR cannot account for the observed f values and f -FWHM relation, nor for the shape of (at least) C IV line –a thin disk model can explain most of the observables related to the C IV broad line, but is inconsistent with H data –a thicker disk may represent a valid model for H –since R BLR (H)>R BLR (C IV ), we suggest that a disk the thickness of which increases with R may explain the differences in the behaviour of the two lines –radio loudness do not affect directly the BLR geometry. Dust torus Accretion disk H emitting clouds C IV emitting clouds

11

12 FeII template subtraction and Gauss-Hermite polynomials

13 Direct measures on data or fit?

14 The host galaxy of quasars In quasars, the nuclear light overwhelms the galaxy luminosity; the surface brightness is ∝ (1+z) -4 The observed image is: (galaxy + nucleus) ⊗ PSF We use our Astronomical Image Decomposition and Analysis (AIDA) software in order to: –Model the PSF on the field stars; –Superimpose a nuclear point-like source to a galaxy model; –Convolve them with the PSF model and fit it to the observed quasar light profile. The host galaxy luminosity and morphology (according to the best-fitting galaxy model) are thus found. QSO PSF

15 AIDA Widget

16 Bibliography A pdf presentation of AIDA is available at: http://www.math.unipa.it/~daa_erice07/contributors/uslenghi.pdf Bettoni D., Falomo R., Fasano G., Govoni F., 2003, A&A, 399, 869 Collin S., Kawaguci T., Peterson B.M., Vestergaard M., 2006, A&A, 456, 75 Decarli R., Labita M., Treves A., Falomo R., 2007, accepted for publication in MNRAS Kaspi S., et al., 2000, ApJ, 533, 631 Kaspi S., et al., 2005, ApJ, 629, 61 Kaspi S., et al., 2007, ApJ, 659, 997 Kormendy J., Richstone D., 1995, ARA&A, 33, 581 Labita M., Treves A., Falomo R., Uslenghi M., 2006, MNRAS, 373, 551


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