The Lyot coronagraph can achieve significant on-axis starlight suppression when equipped with a notch filter image mask. Notch filter masks are placed in the focal plane and have small intricate features. They must be manufactured using nanofabrication techniques, when designed for coronagraphs operating at visible or near infrared wavelengths. This process often involves depositing an opaque material onto a glass substrate whereby a pattern is then etched. The substrate however can be a source of internal reflections and chromatic aberrations that limit the coronagraph's dynamic range and broadband performance. We present theoretical and experimental work on a new series of image masks that do not require the support of a glass substrate. We show that by adding periodic bar structures of appropriate spacing, it may be possible to manufacture a Silicon binary notch filter mask that is “free-standing”.

We investigate the evolution of damped Ly$\alpha$ absorption systems (DLA) from hierarchical structure formation models by exploring the basic properties of DLA host-galaxies (DLA galaxies) to clarify the connection between DLAs and galaxies. We find that DLA galaxies primarily consist of low surface brightness dwarf galaxies. For example, at redshift $z \le 1$, DLA galaxies have typical radius 3 kpc, surface brightness 22–27 mag arc-sec$^{-2}$, and star formation rate $10^{-2}$ M$_{\odot}$/yr. We discuss selection effects in the detection in emission caused by compactness and brightness. Finally, we explore the radio properties at $z=0$ by comparing the observational results from blind radio surveys.

REM is a fast slewing automatic telescope dedicated to the prompt observation of GRB afterglows. The telescope automatically reacts to GCN alerts, beginning follow-up observations in both infra-red and optical wavelengths. Recent observations of GRBs have shown the capabilities of REM to begin follow up observation in the order of 10s of seconds after the burst.

We present gamma–ray and X-ray analysis of GRB040223 observed by INTEGRAL and XMM-Newton. GRB 040223 has a peak flux of $(1.6 \pm 0.1) \times 10^{-8}$ ergs cm$^{-2}$ s$^{-1}$, a fluence of (4.4 $\pm$ 0.4) $\times$ 10$^{-7}$ ergs cm$^{-2}$ and a steep photon power law index of −2.3 $\pm$ 0.2, in the energy range 20–200 keV. The steep spectrum implies that it is an X-ray rich GRB with emission up to 200 keV and $E_{\rm peak}<20$ keV. The luminosity-lag relationship was used to obtain a redshift $z=0.10^{+0.04}_{-0.02}$. The isotropic energy radiated in $\gamma$-rays and X-ray luminosity after 10 hours are both orders of magnitude less than classical GRBs.

The abundance patterns of extremely metal-poor (EMP) stars provide us with important information on nucleosynthesis in supernovae (SNe) formed in a Pop III or EMP environment, and thus on the nature of the first stars in the Universe. We review nucleosynthesis yields of various types of those SNe, focusing on core-collapse (black-hole-forming) SNe with various progenitor masses, explosion energies (including Hypernovae), and asphericity. We discuss the implications of the observed trends in the abundance ratios among iron-peak elements, and the large C/Fe ratio observed in certain EMP stars with particular attention to recently discovered hyper metal-poor (HMP) stars. We show that the abundance pattern of the HMP stars with [Fe/H] <−5 and other EMP stars are in good accord with those of black-hole-forming supernovae, but not pair-instability supernovae. This suggests that black-hole-forming supernovae made important contributions to the early Galactic (and cosmic) chemical evolution. Finally we discuss the nature of First (Pop III) Stars.

We present a measurement of $\left[\rm{O}/\rm{Fe}\right]$ versus $\left[\rm{Fe}/\rm{H}\right]$ in the $z>2$ IGM derived from a sample of 23 Lyman Limit systems whose column density lies in the range $19.0\le\log N_{HI}\le 20.2$ cm$^{-2}$. The systems span a metallicity range of $-2.70 \le \left[\rm{Fe}/\rm{H}\right]\le -0.50$, allowing for a direct comparison with similar studies of stars within the Milky Way. Although the Lyman Limit systems can be highly ionised, the effects of ionisation on the determination of $\left[\rm{O}/\rm{Fe}\right]$ is minor for most of the systems in the sample. The data appear to show a decrease in $\left[\rm{O}/\rm{Fe}\right]$ with increasing metallicity with an approximate slope of $m\simeq-0.55$. We also determine a best fit power law slope of $\alpha=-1.86 \pm 0.2$ to the column density distribution $f_{HI}(N)$ for $19.0 \le\log N_{HI}\le 20.2$ cm$^{-2}$.

The extremely large telescopes (ELTs) are built at huge financial cost and usually involve partnership among several bodies/nations. Consequently and naturally, telescope time allocations in many, if not most, of such telescopes are based either directly or indirectly on the monetary contributions of the partners. This paper examines the economy, sociology, science and politics of the ELTs and their implications for the astronomers and/or astronomy in poorer developing nations.

Using a sample of over 100 nucleated Virgo cluster dEs from the SDSS we show that interchanging nucleus and galaxy colours does not alter the colour-magnitude relation. No significant difference is found between nuclei and their parent galaxies in a multicolour comparison except for a weak tendency that some nuclei are slightly redder than their hosts.

We investigated two-stage combinations from three methods, nulling interferometer, nulling coronagraph, and modified pupil, calculating reduced intensity profile of a resolved central star and transmission for exo-planets. An achievable dynamic range can be derived by dividing the residual halo intensity of the star by the transmitted peak intensity of the planet. For observation parameters, here assumed are the wavelength of 600 nm in optical and the telescope diameter of 3 m. The combination of the nulling interferometer and the four-quadrant phase mask coronagraph showed the best performance reaching to $10^{-10}$ dynamic range at 100mas distance from the central star among five candidates of combination using nulling interferometer, achromatic interfero-coronagraph, four-quadrant phase mask, and shaped pupil method.

This talk reviews the observations of the high-energy emission of young supernovae, providing an update from previous reviews in 1995 and 2003. A summary plot shows the number distribution of X-ray luminosities, currently totalling 25 supernovae, from which it is clear that SN IIP are weak X-ray sources, SN IIn are very luminous sources, and SN Ib/c cover a broad range in luminosity.

We present preliminary results of a detailed analysis of the $z=3.55$ Lyman limit system observed in the optical spectrum of Q2000-330. We have fitted Voigt profiles to the system to determine the column densities and Doppler parameters of its many components. For its major components we have also determined the ionisation fraction of the gas and obtained crude estimates of metallicities. We find order of magnitude variations in ionisation fraction and metallicity in components separated by as little as 150 km s$^{-1}$ in velocity space. This work is presented as an example of a campaign we have begun to collect such information on a sample of $\sim 100$ such systems in an effort to accurately characterise this enigmatic and important class of quasar absorption line systems.

The Terrestrial Planet Finder Coronagraph (TPFC) is a National Aeronautics and Space Administration (NASA) exploration mission to directly detect and characterize terrestrial exoplanets at visible and near-infrared wavelengths. The TPFC mission is currently in a “pre-formulation” stage where requirements and designs are traded. TPFC must distinguish a planet that is more than 10 orders of magnitude fainter than its parent star at a separation of 62 mas ($\lambda = 600$ nm). Coronagraphic detection requires a large aperture telescope to resolve the exoplanet from its parent star, and great system (wavefront) stability during detection and characterization. This paper discusses the design considerations, trade studies and analysis leading to the current, “reference” design for the TPFC telescope. We present the salient features of the design and the most significant structural, thermal and optical analysis results. We also discuss the planned model validation and performance verification approach.

The first generation of stars to form in the universe may have been very massive, and, due to the absence of initial metals, they could have retained most of their mass until their death and thus explode as pair instability supernovae. These supernovae encounter the late burning phases beyond carbon burning in an implosive/explosive way, leading to very powerful thermonuclear-powered explosions, up to a hundred times more powerful than ordinary supernovae. For primordial stars, these explosions also produce a peculiar abundance pattern, showing a strong odd-even pattern in the elemental abundances, a sharp drop-off of nucleosynthetic production beyond the iron group, and no r-process contribution. These results are greatly altered if only a small mass of 14N is dredged down into the helium burning core before the star becomes unstable. Such mixing could be a consequence of differential rotation or convective overshooting.

Until recently, dwarf elliptical galaxies (dEs) were mostly believed to be gas-less systems, having lost their interstellar medium (ISM) through a galactic wind or through ram pressure stripping in the dense cluster environment. However, recent H$\alpha$ and HI surveys indicate that some dEs in cluster environments are able to retain part of their gas (Drinkwater et al. (2001), Conselice et al. (2001)). In a detailed observational study of the ISM of a sample of Fornax dEs, we detected genuine dEs containing warm and cold gas (De Rijcke et al. (2003), Michielsen et al. (2004), Buyle et al. (2005)).

Using an N-body/SPH code, we explore the two gas-removing scenarios in order to assess their efficiency in removing the ISM from dEs. We simulated dEs subjected to ram pressure stripping by the intracluster medium (ICM) and found that, while small dEs are instantaneously stripped, more massive dEs are able to retain part of their ISM over long time-scales. Isolated dEs on the other hand are expected to lose their gas through a galactic wind. Our simulations show that supernova explosions can blow (super)bubbles in the ISM, thereby ejecting part, though not all, of the ISM.

The scientific goals for the TMT (Thirty Meter Telescope) are consistent with all the objectives outlined by the top level astronomy review committees in both Canada and the United States. In addition to powerful seeing-limited instruments, TMT will include instruments that will take advantage of the full diffraction-limited performance of a 30m telescope at wavelengths $\gt 1 \mu {\rm m}$. This will enable TMT to meet the challenges presented by the scientific requirements and will provide full complementarity with future project like JWST and ALMA. This paper presents a brief review of the status of TMT and an overview of the instruments and their adaptive optic systems.

The original Magellan partner institutions and the Smithsonian Astrophysical Observatory, Texas A&M University, and The University of Texas at Austin have undertaken to construct an extremely large telescope in Chile. The Giant Magellan Telescope is built around seven 8.4m borosilicate honeycomb mirror segments, six of which are off-axis. The collecting area is equivalent to that of a filled aperture 21.5m in diameter, the angular resolution is equivalent to a filled 24.4m telescope. The telescope mount is highly compact and delivers light to the focal plane in two reflections. Instruments are mounted at either a low-background straight Gregorian focus, or to one of several folded Gregorian foci behind the center primary mirror segment. A set of candidate first generation instruments has been defined and conceptual design studies are underway. The first off-axis primary mirror segment has been cast and will soon be polished as part of a proto-typing program. The current schedule calls for first light in mid 2015. This contribution describes the telescope and the considerations that led to its design.

We present a new analysis of the abundances observed in extremely metal poor stars based on both a new generation of theoretical presupernova models and explosions of zero metallicity massive stars and a new abundance analysis of an homogeneous sample of stars having $\rm [Fe/H]\leq -2.5$ (Cayrel et al. 2004).

We present preliminary results of a search for candidate dwarf galaxies in the NGC 3665 galaxy group. A $0.1 \times 0.1$ Mpc$^2$ field around the dominant early-type galaxy NGC 3665 was investigated using BRI images from the 2.5m INT WFC archive. A search with the SExtractor yielded 148 dwarf galaxy candidates in the range $-12 > M_B > -16$. The resulting luminosity function for the group can be described by a standard Schechter function.

We discuss the physical properties and the baryonic content of the Warm-Hot Intergalactic Medium (WHIM) at low redshifts. Cosmological simulations predict that the WHIM contains a large fraction of the baryons at $z=0$ in the form of highly-ionised gas at temperatures between $10^5$ and $10^7$ K. Using high-resolution ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE) we have studied the WHIM at low redshifts by searching for intervening O VI and thermally broadened Lyman $\alpha$ (BLA) absorption toward a number of quasars and active galactic nuclei (AGNs). Our measurements imply cosmological mass densities of $\Omega_b$(O VI)$\geq0.0022 h_{75}^{-1}$ and $\Omega_{b}$(BLA)$\geq0.0035\,h_{75}^{-1}$. Our results suggest that the WHIM at low $z$ contains more baryonic mass than stars and gas in galaxies.

Owing to the rapid progress of space sciences and the high-energy astrophysics in the past 2–3 decades, historical supernova records have made important contributions to modern astrophysics and will continue to do so in the future. The main topics here are the earliest supernova observed by human beings and the AD393 guest star as well as our new concept of “Po stars”