The Atacama Large Millimeter/Submillimeter Array (ALMA) is an international effort to construct an instrument capable of matching the exquisite imaging properties of optical space telescopes at millimeter and submillimeter wavelengths. ALMA science will transform our vision of the cold, dusty, and gaseous universe, from extrasolar planets to the youngest galaxies.

We discuss the present state of the art of the solar quadrupole moment from planetary ephemerides.

We present the preliminary results of the X-ray spectral analysis of one of the largest samples of X-ray selected BLAGN assembled so far from the XMM-2dF Wide Angle Survey. The sample, with 641 spectroscopically identified BLAGN, provides a unique resource to carry out a statistical analysis of the emission properties of these objects over a broad range of X-ray luminosities and redshifts. The X-ray spectra of the majority of the objects were best fitted with a power law with a near constant mean spectral photon index. No obvious trend of this spectral parameter with X-ray luminosity or redshift was found.

We measured the mean photon index of our objects to be ∼1.96 ± 0.05 with an intrinsic dispersion σ=0.22±0.03. X-ray absorption was detected in ∼8% of the sources, with no preferred luminosity or redshift and having typical values of the absorbing column density ≤1022 cm−2.

The gravitational instability of shells and supershells and its relevance to the triggering of the star formation in a turbulent ISM is discussed. The IMF of the self-gravitating clumps formed out of shells is computed and triggering time is compared with the shell dissolution time due to chaotic motions.

Galactic clusters have well organized directions of their velocities at the instant of birth measured with respect to the local circular velocity. Preferential directions survive more than 100 Myrs. This can only be explained by star formation triggered by spiral arms.

Because PG 2303+243 had not been observed since 1992, we have arranged the mini-campaign of six observatories on PG 2303+243 in 2004 Sep. 5-21 for the more detailed frequency analysis of variations. The amplitudes of the most frequencies change even during the one night and some frequencies can disappear or appear in one year. Probably it is resonance effect. We have estimated 69 frequencies of pulsations and their amplitudes according the observations from 2004 and 36 frequencies and its amplitudes from 2005.

The method of spectra disentangling has been applied in many studies of different stellar systems up to the distance of Andromeda Galaxy. In some of these applications the underlying assumptions are not precisely satisfied. This is why new generalizations of the method are needed. Ways to overcome these problems are discussed here.

We used the long term spectroscopic observations of Mrk 110 (Hα and Hβ lines) to investigate the gravitational field influence on spectral line profiles. We found that effects of gravitational field can be measured and that the lines are more intense where the emission is originating close to the central black hole of Mrk 110.

Comets account for a small but very significant fraction of impactors on the Earth. Although the total number of Earth-crossing comets is modest as compared with asteroids, the more eccentric and inclined orbits of the comets result in much higher encounter velocities with the planet. Additionally, some Earth-crossing comets are significantly larger than any current near-Earth asteroids (NEAs); comets 1P/Halley and C/1995 O1 Hale-Bopp are good examples of this. Thus, the most energetic impacts on the Earth likely result from comets and not NEAs. The mean impact probability for long-period comets is 2.4× 10−9 per comet per perihelion passage, assuming the perihelion distribution of Everhart (1967), with a most probable encounter velocity of 53.5 km sec−1. There are 21 known Earth-crossing Jupiter-family comets with a mean impact probability of 1.6× 10−9 per comet per year and a most probable encounter velocity of 17.0 km sec−1. For the 16 known Earth-crossing Halley-type comets the mean impact probability is 1.2× 10−10 per year with a most probable encounter velocity of 51.3 km sec−1. The poor knowledge of the size distribution of cometary nuclei makes it difficult to estimate actual impact energies at this time, though that situation is slowly improving, in particular for the Jupiter-family comets.

We recently launched a comprehensive ground based (ESO/VLT/NTT) and space (HST & SST) study of the present and past star formation in the Small Magellanic Cloud (SMC), in clusters and in the field, with the goal of understanding how star and cluster formation occur and propagate in an environment of low metallicity, with a gas and dust content that is significantly lower than in the Milky Way. In this paper, we present some preliminary results of the “young cluster” program, where we acquired deep F555W (~V), and F814W (~I) HST/ACS images of the four young and massive SMC star clusters: NGC 346, NGC 602, NGC 299, and NGC 376.

We present slit-scan observations of the Hα and [NII] 6584 Å emission lines toward the HL Tau jet with the 8.2m Subaru Telescope. HL Tau is an active young star in transitional phase from an embedded class I protostar to a class II pre-main-sequence star, and it is located in the northeastern part of the L1551 dark cloud. The slit-scan technique at high spectral resolution (R=3.6×104) allowed for studying kinematics of individual features in unprecedented details. The Hα emission shows the main jet component (VLSR ~ −180 km s−1) and distinct lower velocity components (∣VLSR∣<120 km s−1). The [NII] emission is primarily associated with the jet within 10 arcsecond from the source, and also knot B and C ~30 arcsecond away from the source. These are associated with the main jet component, and absent in the lower velocity components. The velocity of Hα and [NII] emissions in the main jet component well matches each other.

Our high-resolution spectra do not show the evidence for the presence of turbulent mixing layers between the jet and surrounding gas. The lower velocity components are associated with individual knots, and explained as the lateral of bow shocks. Their line profiles suggest that shock velocity of the knots A-C is 120~130 km s−1 (Hartigan et al. 1987). The observed [NII]/Hα flux ratio markedly differ between regions: 0.1-0.7 in base of the jet; less than 0.1 in knot A; ~0.2 in knot B; ~0.4 in knot C; and ~0.7 in knot D. Shock models predict that the [NII]/Hα flux ratio reflects the ionization of the preshock gas. This results from enhancement of N+ via the charge exchange reaction (Osterbrock 1989; Bacciotti & Eislöffel 1999). We perform more detailed comparisons between models and observations (Hartigan et al. 1987; Morse et al. 1994). The base of the jet and knot D show high [NII]/Hα flux ratios, indicating that the ambient gas surrounding the jet is considerably ionized, or the preshock density of the ambient gas is significantly low. In contrast, the knots A-C exhibit low [NII]/Hα flux ratios, indicating that the ambient gas surrounding the jet is almost neutral, or the preshock density of the ambient gas is significantly high. The [NII]/Hα flux ratio increases from knot A (0.1) to knot D (~0.7). This suggests that the ionization fraction of the ambient gas increases away from the source, or the preshock density of the ambient gas decreases away from the source.

We study a complete and distance-limited sample of 25 LINERs, 21 of which have been imaged with the Hubble Space Telescope to study their physical properties and to compare their radio and optical properties with those of other samples of local AGNs, namely Seyfert galaxies and low-luminosity radio galaxies (LLRG). Our results show that the LINERs population is not homogeneous, as there are two subclasses: i) the first class is similar to LLRG, as it extends the population of radio-loud nuclei to lower luminosities; ii) the second is similar to Seyferts, and extends the properties of radio-quiet nuclei towards the lowest luminosities. The different nature of the various classes of local AGN are best understood when the fraction of the Eddington luminosity they irradiate, Lo/LEdd, is plotted against the nuclear radio-loudness parameter: Seyferts are associated with relatively high radiative efficiencies Lo/LEdd ≳ 104 (and high accretion rates onto low mass black holes); LLRG are associated with low radiative efficiencies (and low accretion rates onto high black hole masses); all LINERs have low radiative efficiency (and accretion rates), and can be radio-loud or radio quiet depending on their black hole mass.

In the frame of the collaboration of several Southern European observatories, we are examining a number of eclipsing binary systems in search for evidence of pulsating phenomena. We hope our candidate systems will be suitable for subsequent astroseismological studies. As a first step towards this end, we are analyzing spectroscopic observations of several such binary stars; these observations have been made at the National Astronomical Observatory Rozhen, Bulgaria, in the period from 2002 to 2005, and the reduction was done at the Astronomical Observatory of Belgrade, Serbia. The measurements of radial velocities and RV curve analysis are in preparation.

We discuss that in the extreme relativistic limit, i.e., when z ≫ 1, where z is the surface gravitational redshift, there could be radiation pressure supported and dominated stars with arbitrary gravitational mass, high or low. Such objects are called Eternally Collapsing Objects (ECOs). ECOs are practically as compact as Schwarzschild black holes (BH) and, observationally, are likely to be mistaken as BHs. Further since any object undergoing continued collapse must first become an ECO before becoming a true BH state characterized by M = 0, the observed BH Candidates are ECOs.

We present NIR spectroscopy of emission lines of a sample of five z≃6 quasars, including fainter objects than observed before. The measured FeII/MgII ratios are around solar and consistent with a lack of evolution of the metallicity of quasar BLRs up to z≃6, suggesting that stars in their hosts formed at z≫6. The BH masses, measured from both MgII and CIV line widths are within the range 2-16×108M⊙, the smallest found in such distant objects.

We consider the possibility to study the nature of MHD turbulence in star-forming regions with three different kinds of polarimetric data, namely, the linear polarization of starlight due to extinction by aligned dust grains, the polarized dust thermal radiation at far infrared or submillimeter wavelengths, and the linear polarization of molecular lines due to the Goldreich-Kylafis effect in the anisotropic MHD medium.

With sensitive radio observations of a Virgo Cluster spiral NGC 4254 we are able to decompose thermal and synchrotron radio emission and, based on the thermal component, construct the SFR distribution within the galaxy, unaffected by dust extinction. The mean SFR per unit area is several times higher than in other galaxies of similar Hubble type. Contrary to other Virgo spirals the SFR distribution is not spatially truncated, in concordance with the observed weak HI deficiency. We propose that the SFR enhancement and the observed disturbed morphology of this galaxy can be attributed to tidal triggering by another nearby cluster member.

I discuss the constraints that can be derived on the abundance of high redshift (z>6) (mini)quasars from the unresolved soft X-Ray background. Furthermore, I will show how existing Lyα surveys can be used to probe the very faint MB≳-21 mag (i.e., ≳7–8 mag fainter than the SDSS quasars) end of the z≥,4.5 quasar luminosity function.

Diffusive shock acceleration (DSA) in test-particle approximation is used for explaining the radio emission from shell-type SNRs.

The theory of the Fundamental Plane (FP) proposed by Secco (2005) is based on the existence of a maximum in the Clausius' Virial (CV) potential energy of a stellar component when it is completely embedded inside a dark matter (DM) halo. At the first order approximation the theory was developed by modeling the two-components with two power-law density profiles and it produces some expectations in fairly good agreement with the observations. We add other predictions of the theory at the same level of approximation about the Zone of Exclusion (ZOE) in k-space and its possible relationship with cosmological scenario. Some of the consequences of the thermodynamical properties of CV maximum are also taken into account.