Piero Rafanelli

Exploring Narrow-Line Seyfert 1 Galaxies through the Physical Properties of Their Hosts*

In this work we address the still open question of the nature of narrow-line Seyfert 1 galaxies (NLS1s): are they really active nuclei with lower mass black holes (BHs) than Seyfert 1 galaxies (S1s) and quasars? Our approach is based on the recently discovered physical connections between nuclear supermassive BHs and their hosting spheroids (spiral bulges or elliptical galaxies). In particular, we compare BH masses of NLS1s and S1s, analyzing the properties of their hosts by means of spectroscopic and photometric data in the optical wavelength domain. We find that NLS1s fill the low BH mass and bulge luminosity values of the MBH-MB relation, a result strongly suggesting that NLS1s are active nuclei in which less massive BHs are hosted by less massive bulges. The correlation is good, with a relatively small scatter fitting simultaneously NLS1s, S1s, and quasars. On the other hand, NLS1s seem to share the same stellar velocity dispersion range as S1s in the MBH-σ* relation, indicating that NLS1s have a smaller BH/bulge mass ratio than S1s. These two conflicting results support in any case the idea that NLS1s could be young S1s. Finally, we do not confirm the significantly nonlinear BH-bulge relation claimed by some authors.

The structure of the protoplanetary disk surrounding three young intermediate mass stars II. Spatially resolved dust and gas distribution

Aims. We present the first direct comparison of the distribution of the gas, as traced by the [O i] 6300 A emission, and the dust, as traced by the 10 μm emission, in the planet-forming region of proto-planetary disks around three intermediate-mass stars: HD 101412, HD 135344 B and HD 179218. Methods. N-band visibilities were obtained with VLTI/MIDI. Simple geometrical models are used to compare the dust emission to high-resolution optical spectra in the 6300 A [O i] line of the same targets. Results. HD 101412 and HD 135344 B show compact (< 2A U) 10μm emission while the [O i] brightness profile shows a double peaked structure. The inner peak is strongest and is consistent with the location of the dust, the outer peak is fainter and is located at 5–10 AU. In both systems, spatially extended PAH emission is found. HD 179218 shows a double ring-like 10 μm emission with the first ring peaking at ∼1 AU and the second at ∼20 AU. The [O i] emitting region is more compact, peaking between 3–6 AU. Conclusions. The disks around HD 101412 and HD 135344 B appear strongly flared in the gas, but self-shadowed in the dust beyond ∼ 2A U. The difference in the gas and dust vertical structure beyond 2 AU might be the first observational evidence of gas-dust decoupling in protoplanetary disks. The disk around HD 179218 is flared in the dust. The 10 μm emission emerges from the inner rim and from the flared surface of the disk at larger radii. No dust emission is detected between ∼3–15 AU. The oxygen emission seems also to come from a flared structure, however, the bulk of this emission is produced between ∼1–10 AU. This could indicate a lack of gas in the outer disk or could be due to chemical effects which reduce the abundance of OH – the parent molecule of the observed [O i] emission – further away from the star. It may also be a contrast effect if the [O i] emission is much stronger in the inner disk. We suggest that the three systems, HD 179218, HD 135344 B and HD 101412, may form an evolutionary sequence: the disk initially flared becomes flat under the combined action of gas-dust decoupling, grain growth and dust settling.

Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio frequencies to X-rays, and supplement these with information available from online catalogs and the literature in order to cover the full electromagnetic spectrum. This is the largest known multiwavelength survey for this type of source. We detected 90% of the sources in X-rays and found 17% at gamma rays. Extreme variability at high energies was also found, down to timescales as short as hours. In some sources, dramatic spectral and flux changes suggest interplay between a relativistic jet and the accretion disk. The estimated masses of the central black holes are in the range

Detailed Analysis of Balmer Lines in a Sloan Digital Sky Survey Sample of 90 Broad-Line Active Galactic Nuclei

\sim 10^{6-8}M_{\odot}

Optical and infrared properties of V1647 Orionis during the 2003–2006 outburst - II. Temporal evolution of the eruptive source

, smaller than those of blazars, while the accretion luminosities span a range from

Soft X-ray properties of a spectroscopically selected sample of interacting and isolated Seyfert galaxies

\sim 0.01

Parent population of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

to

A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

\sim 0.49

Balmer Emission Line Profiles and Complex Properties of Broad-Line Regions in Active Galactic Nuclei

times the Eddington limit, similar to those of quasars. The distribution of the calculated jet power spans a range from

The Interpretation of the Emission Spectra of the Seyfert 2 Galaxy NGC 7130: Determination of the Active Galactic Nucleus and Starburst Contributions

\sim 10^{42.6}