We study fossil galaxy groups, their hot gas and the galaxy properties. Fossils are more X-ray luminous than non-fossil groups, however, they fall comfortably on the conventional L-T relation of galaxy groups and clusters indicating that their X-ray luminosity and temperature are both boosted, arguably, as a result of their early formation. The central dominant galaxy in fossils have optical luminosity comparable to the brightest cluster galaxies (BCGs), however, the isophotal shapes of the central galaxy in fossils are non-boxy in contrast to the isophotes of majority of the BCGs.

The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) at the University of Hawaii's Institute for Astronomy is a funded project to repeatedly survey the entire visible sky to faint limiting magnitudes (mR ~ 24). It will be composed of four 1.8m diameter apertures each outfitted with fast readout orthogonal transfer Giga-pixel CCD cameras. A single aperture prototype telescopes has achieved first-light in the second half of 2006 with the full system becoming available a few years later. Roughly 60% of the surveying will be suitable for discovery of new solar system objects and it will cover the ecliptic, opposition and low solar-elongation regions. In a single lunation Pan-STARRS will detect about five times more solar system objects than the entire currently known sample. Within its first year Pan-STARRS will have detected 20,000 Kuiper Belt Objects and by the end of its ten year operational lifetime we expect to have found 107 Main Belt objects and achieve ~90% observational completeness for all NEOs larger than ~300m diameter. With these data in hand Pan-STARRS will revolutionize our knowledge of the contents and dynamical structure of the solar system.

We have found photometric indications that Interacting Eclipsing Binaries of early to mid F spectral type (and possibly A) have strong magnetic activity which would arise from convective atmospheres. Light curve solutions and periodicity studies revealing spots, magnetic breaking and magnetic cycles are presented in XZ CMi, V965 Cyg and V963 Cyg.

A recent analysis of HST optical images of 34 nearby early-type active galaxies and of a matched sample of 34 inactive galaxies – both drawn from the Palomar survey – shows a clear excess of nuclear dusty structures (filaments, spirals and disks) in the active galaxies. This result supports the association of the dusty structures with the material which feeds the supermassive black hole (hereafter SMBH). Among the inactive galaxies there is instead an excess of nuclear stellar disks. As the active and inactive galaxies can be considered two phases of the “same” galaxy, the above findings and dust morphologies suggest an evolutionary scenario in which external material (gas and dust) is captured to the nuclear region where it settles and ends up feeding the active nucleus and replenishing the stellar disk – which is hidden by the dust in the active galaxies – with new stars. This evolutionary scenario is supported by recent gas kinematics of the inner few hundred parsecs of NGC 1097, which shows streaming motions (with velocities ∼50 km s−1) towards the nucleus along spiral arms. The implied large scale mass accretion rate is much larger than the one derived in previous studies for the nuclear accretion disk, but is just enough to accumulate one million solar masses over a few million years in the nuclear region, thus consistent with the recent finding of a young circumnuclear starburst of one million solar masses within 9 parsecs from the nucleus in this galaxy.

We summarize findings from imaging surveys of 143 early-type galaxies in the Virgo and Fornax Clusters. Using deep HST images in the F475W (g) and F850LP (z) band-passes obtained with the Advanced Camera for Surveys (ACS), we have examined the central structure of the program galaxies, finding clear evidence for a compact stellar nucleus in ∼ 75% of the sample. The formation of early-type galaxies of low- and intermediate-mass is often – but not always – accompanied by the formation of a compact stellar nucleus.

We list below a few problems whose resolution might bring new lights on the impacts of the first stellar generations on the early phases of the evolution of the galaxies.

The Arecibo Galaxy Environment Survey (AGES, Auld et al. 2006) will map ~200 square degrees over the next years using the ALFA feed array at the 305-m Arecibo Telescope. AGES is specifically designed to investigate various galactic environments from local voids to interacting groups and cluster of galaxies. AGES will map 20 square degrees in the Coma-Abell1367 supercluster including the Abell cluster 1367 and its outskirts (up to ~2 virial radii). In Spring 2006 we nearly completed the observations of 5 square degrees in the range 11:34< RA< 11:54, 19:20<Dec<20:20 covering all the cluster core and part of its infalling region reaching a 5 sigma detection limit of M(HI)~4×108M⊙ (assuming a velocity width ~200 km~s−1) at the distance of Abell1367 (~92 Mpc). An HI selected sample has been extracted from the datacube obtaining a catalogue of fluxes, recessional velocities, positions and velocity widths. We present a preliminary analysis of the properties of the HI sources and report the discovery of HI diffuse features within interacting groups at the periphery of Abell1367.

The Minimum Orbit Intersection Distance (MOID) between two confocal Keplerian orbits is a useful tool to know if two celestial bodies can collide or undergo a very close approach. We describe some results and open problems on the number of local minimum points of the distance between two points on the two orbits and the position of such points with respect to the mutual nodes. The errors affecting the observations of an asteroid result in uncertainty in its orbit determination and, consequently, uncertainty in the MOID. The latter is always positive and is not regular where it vanishes; this prevents us from considering it as a Gaussian random variable, and from computing its covariance by standard tools. In a recent work we have introduced a regularization of the maps giving the local minimum values of the distance between two orbits. It uses a signed value of the distance, with the sign given to the MOID according to a simple orientation property. The uncertainty of the regularized MOID has been computed for a large database of orbits. In this way we have searched for Virtual PHAs, i.e. asteroids which can belong to the category of PHAs (Potentially Hazardous Asteroids) if the errors in the orbit determination are taken into account. Among the Virtual PHAs we have found objects that are not even NEA, according to their nominal orbit.

We present our recent work on the conditions under which star formation occurs in a metal-poor environment, the Large Magellanic Cloud ([Fe/H] ~ −0.4). Water masers are used as beacons of the current star formation in H II regions. Comparing their location with the dust morphology imaged with the Spitzer Space Telescope, and additional Hα imaging and groundbased near-infrared observations, we conclude that the LMC environment seems favourable to sequential star formation triggered by massive star feedback (Oliveira et al. 2006). Good examples of this are 30 Doradus and N 113. There are also H II regions, such as N 105A, where feedback may not be responsible for the current star formation although the nature of one young stellar object (YSO) suggests that feedback may soon start making an impact. The chemistry in one YSO hints at a stronger influence from irradiation effects in a metal-poor environment where shielding by dust is suppressed (van Loon 2005).

The solar magnetic field and its associated atmospheric activity exhibits periodic variations on a number of time scales. The 11-year sunspot cycle and its underlying 22-year magnetic cycle are, besides the 5-minute oscillation, the most widely known. Amplitudes and periods range from a few parts per million (ppm) and 2–3 minutes for p-modes in sunspots, a few 10 ppm and 10 minutes for the granulation turn around, a few 100 ppm and weeks for the lifetime of plages and faculae, 1000 ppm and 27 days for the rotational signal from spots, to the long-term cycles of 90 yr (Gleissberg cycle), 200 - 300 yr (Wolf, Spörer, Maunder minima), 2,400 yr from 14C tree-ring data, and possibly in excess of 100,000 yr.

A sample of potential massive starforming regions identified at 170 m by ISO was observed in the submillimeter and millimeter regime. These observations allow us to infer physical properties of the molecular cloud cores. Two sources are presented in detail: ISOSS J23053+5953 and J183640221 show viable candidates for massive protocluster cores. Our analysis shows very low temperatures and low levels of turbulence of the major mass fraction in the molecular cloud cores besides active star formation at an early evolutionary stage. These conditions seem similar to the low mass case and may precede phases of luminous infrared emission observed towards young massive protostars.

We have performed numerical simulations which were designed to further our understanding of the turbulent interstellar medium (ISM). Our simulations include a multi-phase thermodynamic model of the ISM, magnetic fields, and sheared rotation, allowing us to study the effects of the magnetorotational instability (MRI) in an environment containing high density cold clouds embedded in a warm, low density, ambient medium. These models have shown that the MRI is indeed a significant source of turbulence, particularly at low mean densities typical of the outer regions of the Milky Way, where star formation rates are low, but high levels of turbulence persist. Here, we summarize past findings, as well as our most recent models which include vertical stratification, allowing us to self-consistently model the vertical distribution of material in the disk.

Thermal convection occurs in most objects that populate our Universe, whenever radiation is insufficient to transport the heat because the medium is too opaque. In astrophysical objects convection involves a wide range of spatial and temporal scales - experts call this turbulence - which makes it rather difficult to model. For this reason convection remains one of the major uncertainties when modeling stars and planets, and this is partly true also for accretion disks. However, substantial progress has been achieved during the past years, both in the numerical simulation of convective regions and in the observation of convective flows by various new techniques.

In the past decade high resolution measurements in the infrared employing adaptive optics imaging on 10m telescopes have allowed determining the three dimensional orbits stars within ten light hours of the compact radio source at the center of the Milky Way. These observations show the presence of a three million solar mass black hole in Sagittarius A* beyond any reasonable doubt. The Galactic Center thus constitutes the best astrophysical evidence for the existence of black holes which have long been postulated, and is also an ideal ‘lab’ for studying the physics in the vicinity of such an object. Remarkably, young massive stars are present there and probably have formed in the innermost stellar cusp. Variable infrared and X-ray emission from Sagittarius A* are a new probe of the physical processes and space-time curvature just outside the event horizon.

Using the Very Large Array (VLA), we have detected the HCO+(1–0) emission line towards the Cloverleaf quasar (z = 2.56; Riechers et al. 2006). This is the first detection of ionized molecular gas emission at high redshift (z>2). HCO+ emission is a star formation indicator similar to HCN, tracing dense molecular hydrogen gas within star-forming molecular clouds. We find a HCO+/CO luminosity ratio of 0.08 and a HCO+/HCN luminosity ratio of 0.8 for the Cloverleaf. These ratios fall within the scatter of the same relationships found for low–z star–forming galaxies. However, a HCO+/HCN luminosity ratio close to unity would not be expected for the Cloverleaf if the recently suggested relation between this ratio and the far–infrared luminosity (Graciá–Carpio et al. 2006) were to hold. We conclude that a ratio between HCO+ and HCN luminosity close to 1 is likely due to the fact that the emission from both lines is optically thick and thermalized and emerges from dense regions of similar volumes. We conclude that HCO+ is potentially a good tracer for dense molecular gas at high redshift.

Deep surveys conducted during the past decades have shown that galaxies in the distant universe are generally of more irregular shapes, and are disky in appearance and in their star formation rate, compared to galaxies in similar environments in the nearby universe. Given that the merger rate between z= 2 and the local universe is far from adequate to account for this observed morphological transformation rate, an internal mechanism for the morphological transformation of galaxies is to be sought, whose operation can be further aided by environmental factors. The secular evolution mechanism, especially with the discovery of a collisionless dissipation mechanism for stars within the secular evolution paradigm, has provided just such a framework for understanding the morphological evolution of galaxies across the Hubble time. In this paper we will summarize the past theoretical results on the dynamical mechanisms for secular evolution, and highlight new results in the analysis of the observational data, which confirmed that density waves in physical galaxies possess the kind of characteristics which could produce theáobserved rates of morphological transformation for both cluster and field galaxies.

In an effort to obtain further observational evidences for secular evolution processes in galaxies, as well as observational constraints to current theoretical models of secular evolution, we have used BVRI and Ks images of a sample of 18 barred galaxies to measure the lengths and colours of bars, create colour maps and estimate global colour gradients. In addition, applying a method we developed in a previous article, we could distinguish for 7 galaxies in our sample those whose bars have been recently formed from the ones with already evolved bars. We estimated an average difference in the optical colours between young and evolved bars that may be translated to an age difference of the order of 10 Gyr, meaning that bars may be long standing structures. Moreover, our results show that, on average, evolved bars are longer than young bars. This seems to indicate that, during its evolution, a bar grows longer by capturing stars from the disk, in agreement with recent numerical and analytical results.

Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to the nearly uniformly rotating radiative interior takes place in a narrow tachocline, which is likely important to the operation of the solar magnetic cycle. The convection-zone rotation displays zonal flows, regions of slightly more rapid and slow rotation, extending over much of the depth of the convection zone and converging towards the equator as the solar cycle progresses. In addition, there is some evidence for a quasi-periodic variation in rotation, with a period of around 1.3 yr, at the equator near the bottom of the convection zone.

The Canadian Astronomy Data Centre manages a heterogeneous collection of data from the following ground and space-based telescopes: CFHT, DRAO, FUSE, Gemini, HST, JCMT, and MOST. The archive data models implemented for these data collections are ten years old and pre-date two important developments: the Virtual Observatory and the systematic generation and management of data products. Three years ago, we began the process of supporting access to processed data products through IVOA protocols such as SIA by building a layer over the archive data models. Today, we now realise that this approach of layering VO models on archive models is not sufficient and that every archive must be re-tooled to properly support the VO – from the storage model through to the query, processing and access models. The CADC has begun an ambitious software development effort to implement a new infrastructure to serve both telescope archive and Virtual Observatory needs.

Our aim is to study the stellar kinematics in hosts of AGN. We do so by measuring nuclear stellar velocity dispersions (σ⋆). Our sample comprises spectra of 78 objects, 69 of which are Seyfert galaxies, in the region around the λλ8498.02, 8542.09, 8662.14 Calcium triplet (CaT). We investigate two methods to measure σ⋆: (1) the direct fitting method (DFM), which makes use of our stellar population synthesis code Starlight, and (2) the cross-correlation method (CCM), for which we use the fxcor package in IRAF. Both methods yield velocity dispersions consistent to within 19 km/s on-average. We have also measured the CaT equivalent width (WCaT) and the λ3933 CaII K equivalent width (WK) for the objects in our sample. Other studies have shown that WK is a powerful tracer of starbursts in Seyfert nuclei, so we check if WCaT can be used in the same way. We have also analysed a sub-sample of 34 spatially resolved objects with reasonably good off-nuclear signal-to-noise. We study the spatial variations of both σ⋆ and WCaT. We see no dilution in WCaT for composite starburst + Seyfert 2 galaxies, in contrast to the dilution in the WK (studied by other authors) for the same objects.