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.

The Virtual Observatory (VO) is driven partly by new science goals, partly by external technological changes, and partly by the flood of data coming our way. More astronomy is done on line through organised ‘science ready’ archives, and with processed data (source catalogues etc) from large survey projects. Users assume on-line availability of anything useful. The normal methods to date are to download files and analyse them at home, but very likely in the future data will be analysed in situ and analysis software will be as standardised as data reduction software is now. Many science goals require combining data from multiple archives (e.g. crossmatching different wavelengths), and often demand the processing of huge amounts of data, e.g. rare object searches, computing correlation functions, etc. All users want to be ‘power users’.

Small aperture (<1m, typically 20–50 cm) optical telescopes with adequate back-end instrumentation (e.g. photometer, CCD camera and CCD spectrograph) can be used for spreading the joy and excitement of observational astronomy among postgraduate and research students in colleges and universities. On the basis of our experience over a decade of observing with small optical telescopes it has been amply demonstrated that such a facility, which any university can hope to procure and maintain, can be effectively used for teaching and research. The Physics Department of Pt. Ravishankar Shukla University at Raipur, India offers Astronomy & Astrophysics as one of the specializations of its MSc program in Physics. A set of observational exercises has been incorporated with a view to provide training in observations, analysis and interpretation of astronomical data. Observing facilities available in the department include 8”–14” aperture telescopes equipped with a photometer, CCD camera and a CCD spectrograph. A facility of this kind is ideally suited for continuous monitoring of a variety of variable stars, and thus can provide valuable data for understanding the physics of stellar variability. This is especially true for a class of variable stars known as chromospherically active stars. The stars belonging to this class have variable light curves that change from year to year in a rather strange way. A large fraction of these active stars are bright; hence the importance of small aperture telescopes for collecting much-needed photometric data. For over a decade the research activity using the 14” optical telescope has focused on photometric monitoring of well known and suspected active stars. These data, together with X-ray and radio data from archives as well as spectroscopic data obtained at Indian observatories, has led to the identification of new chromosperically active stars. This paper is aimed at sharing our experiences with the colleagues from the developing world on the usage of small optical telescopes for teaching and research with the objective of spreading the joy of astronomy among young students.

We are studying how stellar masses assemble through cosmic time since the Universe had only 30% of its present age. We are conducting a census of galaxies which covers the end of the most active star-forming phase, using a mass-limited sample of approximately 5,000 objects selected from the VIMOS VLT Deep Survey (VVDS) in the redshift range 0.45 < z < 1.3. With a criterion based on the direct spectral measurement of the 4000Å Balmer break, Dn(4000), we have classified our sample in spectroscopically early and late-type galaxies. The trends existing between stellar mass, spectroscopic classification, and star formation activity are clearly shown in our analysis.

Pulsars can be considered as very precise clocks if they are observed from the barycenter of the Solar system. Pulsar Timing Array (PTA) can be used to establish new astronomical reference frame which describes both space and time properties. Among these arrays most remarkable are the Parks Pulsar Timing Array (PPTA) and Kalyazin Pulsar Timing Array (KPTA).

With the first discovery of surviving pre-solar minerals in primitive meteorites in 1987 a new kind of astronomy emerged, based on the study of stellar condensates with all the detailed methods available to modern analytical laboratories. The pre-solar origin of the grains is indicated by considerable isotopic ratio variations compared with Solar System materials, characteristic of nuclear processes in different types of stars.

One knows currently close to 850 Near Earth Asteroids (NEAs) with diameters 1 km and larger, and one estimates that there may be of the order of 100 000 NEAs with diameters exceeding 140 m. Land and water impacts of NEAs with diameters between 100 m and 500 m will cause major damages.

Star formation on galactic scales is the process driving the evolution of galaxies. It is important to understand its various aspects in the nearby universe to properly interpret high redshift observations, and to construct correct models of the evolution of galaxies. Combining UV (GALEX) and infrared (IRAS) data for 43 nearby spatially resolved galaxies with corollary data (HI,CO), we study the star formation law (“Schmidt” law). The absence of a “threshold radius” in the UV supports the idea that star formation proceed at low gas densities and that the usual threshold observed in H-alpha profiles is a small-number statistic effect.

The WIde-field Nearby Galaxy-cluster Survey (WINGS) is a long term project whose main goal is to establish the zero point and variance of properties of nearby clusters, and galaxies in them, to be used as a local reference in evolutionary studies.

To achieve such objective, wide-field multiwavelenght photometry and optical spectroscopy has been gathered and analysed for a sample of 77 X-ray emitting nearby galaxy clusters.

This contribution shows the current status of the project.

Complete poster contents is reproduced in “On-line Section” and PDF copy is available in http://web.oapd.inaf.it/wings/Docs/IAU2006_Varela.pdf.

The growth of supermassive black holes (SBHs) appears to be closely linked with the formation of spheroids. There is a pressing need to acquire better statistics on SBH masses, since the existing samples are preferentially weighted toward early-type galaxies with very massive SBHs. With this motivation we started a project aimed at measuring upper limits on the mass of the SBHs in the center of all the nearby galaxies (D < 100 Mpc) for which STIS/G750M spectra are available in the HST archive. These upper limits will be derived by modeling the central emission-line widths observed in the Hα region over an aperture of ∼0.1″. Here we present our results for a subsample of 22 S0-Sb galaxies within 20 Mpc.

We have carried out deep BVR surface photometry of 6 cD and cD-like galaxies using the 2.1-m telescope at San Pedro Mártir, cD galaxies are supergiant galaxies (M>1013M⊙) with enormous halos (>100 kpc in radius) surrounding a giant elliptical galaxy, found generally at the centre of rich clusters (Oemler 1976, Schombert 1988). The surface brightness profiles of their halos (envelopes) break from the r1/4 law, containing more light at large radii (Schombert (1988)), although a detailed 1 and 2 dimensional analysis of their morphology has yet to be carried out. There have been four main theories as to the origin of cD envelopes (Schombert (1988) and references within), a) stripping of stars from other cluster member galaxies, b) formation of galaxy and envelope at the same time during the formation of the cluster, c) mergers of cluster members, which do not easily explain the high velocity dispersions in the envelopes (~ 1000 km s−1), d) cooling flows: accumulation of cooling X-ray-emitting ICM gas around the central galaxy. Very red envelopes have been found around some cD's, and star formation biased towards lowmass stars in cooling flows were invoked to explain these red halos, but the expected very bright near-IR halos were not detected (Joy et al. 1995 and references within). Previous detailed studies of cD galaxies (e.g. Mackie 1992) found a range of colour gradients.