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Kinds of Camera Terms modified by Camera Selected AbstractsPHOTOGRAMMETRY OF A 5M INFLATABLE SPACE ANTENNA WITH CONSUMER-GRADE DIGITAL CAMERASEXPERIMENTAL TECHNIQUES, Issue 4 2001R.S. Pappa First page of article [source] Bright Ly, emitters at z, 9: constraints on the LF from HizELS,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2009D. Sobral ABSTRACT New results are presented, as part of the Hi- z Emission Line Survey (HizELS), from the largest area survey to date (1.4 deg2) for Ly, emitters (LAEs) at z, 9. The survey, which is primarily targeting H, emitters at z < 3, uses the Wide Field CAMera on the United Kingdom Infrared Telescope and a custom narrow-band filter in the J band and reaches a Ly, luminosity limit of ,1043.8 erg s,1 over a co-moving volume of 1.12 × 106 Mpc3 at z= 8.96 ± 0.06. Only two candidates were found out of 1517 line emitters and those were rejected as LAEs after follow-up observations. The limit on the space density of bright LAEs is improved by three orders of magnitude, consistent with suppression of the bright end of the Ly, luminosity function beyond z, 6. Combined with upper limits from smaller but deeper surveys, this rules out some of the most extreme models for high-redshift LAEs. The potential contamination of future narrow-band Ly, surveys at z > 7 by Galactic brown dwarf stars is also examined, leading to the conclusion that such contamination may well be significant for searches at 7.7 < z < 8.0, 9.1 < z < 9.5 and 11.7 < z < 12.2. [source] Live Video Montage with a Rotating CameraCOMPUTER GRAPHICS FORUM, Issue 7 2009Zilong Dong Abstract High-quality video editing usually requires accurate layer separation in order to resolve occlusions. However, most of the existing bilayer segmentation algorithms require either considerable user intervention or a simple stationary camera configuration with known background, which is difficult to meet for many real world online applications. This paper demonstrates that various visually appealing montage effects can be online created from a live video captured by a rotating camera, by accurately retrieving the camera state and segmenting out the dynamic foreground. The key contribution is that a novel fast bilayer segmentation method is proposed which can effectively extract the dynamic foreground under rotational camera configuration, and is robust to imperfect background estimation and complex background colors. Our system can create a variety of live visual effects, including but not limited to, realistic virtual object insertion, background substitution and blurring, non-photorealistic rendering and camouflage effect. A variety of challenging examples demonstrate the effectiveness of our method. [source] Design of a Singlet Lens and the Corresponding Aberration Correction Approaches for Cell Phone CameraIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2010Yupeng Zhang Member Abstract A singlet lens model that is designed for future cell phone camera is discussed. The proposed lens model unavoidably introduces significant optical aberration because of its high field angle (maximum field angle 48°). To correct the aberrations, traditional paraxial aberration and third-order Seidel aberration are no longer applicable because the accuracy will decline dramatically when the field angle reaches a high value. In this paper, the main objective is to find an improved first-order aberration equation and an improved third-order Seidel aberration equation using field-dependent coefficients to correct lateral chromatic aberration (LAT) and distortion, respectively, for a high-field-angle singlet lens. The simulation results suggest that improved higher order aberration equations are more accurate to represent real aberrations than the lower order case. However, the chromatic aberration is still visible in the resultant images even though LAT is corrected, because of the differences of blur between different colors caused by axial chromatic aberration (AX) and other monochromatic aberrations such as field curvature. This poses a new research topic as our future work. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Ionized gas in E/S0 galaxies with dust lanesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010Ido Finkelman ABSTRACT We report the results of multicolour observations of 30 E/S0 galaxies with dust lanes. For each galaxy we obtained broad-band images and narrow-band images using interference filters isolating the H,+[N ii] emission lines to derive the amount and morphology of dust and ionized gas. To improve the wavelength coverage we retrieved data from the Sloan Digital Sky Survey and Two Micron All Sky Survey and combined these with our data. Ionized gas is detected in 25 galaxies and shows in most cases a smooth morphology, although knots and filamentary structure are also observed in some objects. The extended gas distribution closely follows the dust structure, with a clear correlation between the mass of both components. An extinction law by the extragalactic dust in the dark lanes is derived and is used to estimate the dust content of the galaxies. The derived extinction law is used to correct the measured colours for intrinsic dust extinction and the data are fitted with a stellar population synthesis model. We find that the H, emission and colours of most objects are consistent with the presence of an ,old' stellar population (,10 Gyr) and a small fraction of a ,young' population (, 10,100 Myr). To check this we closely examine NGC 5363, for which archival Spitzer/Infrared Array Camera and Galaxy Evolution Explorer data are available, as a representative dust-lane E/S0 galaxy of the sample. [source] A study of the massive star-forming region M8 using images from the Spitzer Infrared Array CameraMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2010Dewangan Lokesh Kumar ABSTRACT We present photometry and images (3.6, 4.5, 5.8 and 8.0 ,m) from the Spitzer Infrared Array Camera (IRAC) of the star-forming region Messier 8 (M8). The IRAC photometry reveals ongoing star formation in the M8 complex, with 64 class 0/I and 168 class II sources identified in several locations in the vicinity of submm gas cores/clumps. Nearly 60 per cent of these young stellar objects (YSOs) occur in about seven small clusters. The spatial surface density of the clustered YSOs is determined to be about 10,20 YSOs pc,2. Fresh star formation by the process of ,collect and collapse' might have been triggered by the expanding H ii regions and winds from massive stars. IRAC ratio images are generated and studied in order to identify possible diagnostic emission regions in M8. The image of 4.5/8.0 ,m reveals a Br, counterpart of the optical Hourglass H ii region, while the ratio 8.0/4.5 ,m indicates PAH emission in a cavity-like structure to the east of the Hourglass. The ratio maps of 3.6/4.5, 5.8/4.5 and 8.0/4.5 ,m seem to identify PAH emission regions in the sharp ridges and filamentary structures seen east to west and north-east to south-west in the M8 complex. [source] An HST/ACS view of the inhomogeneous outer halo of M31,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2009J. C. Richardson ABSTRACT We present a high precision photometric view of the stellar populations in the outer halo of M31, using data taken with the Hubble Space Telescope/Advanced Camera for Surveys. We analyse the field populations adjacent to 11 luminous globular clusters which sample the galactocentric radial range 18 ,R, 100 kpc and reach a photometric depth of ,2.5 mag below the horizontal branch (mF814W, 27 mag). The colour,magnitude diagrams are well populated out to ,60 kpc and exhibit relatively metal-rich red giant branches, with the densest fields also showing evidence for prominent red clumps. We use the Dartmouth isochrones to construct metallicity distribution functions which confirm the presence of dominant populations with ,[Fe/H],,,0.6 to ,1.0 dex and considerable metallicity dispersions of 0.2 to 0.3 dex (assuming a 10 Gyr population and scaled-solar abundances). The average metallicity over the range 30,60 kpc is [Fe/H]=,0.80 ± 0.14 dex, with no evidence for a significant radial gradient. Metal-poor stars ([Fe/H],,1.3) typically account for ,10,20 per cent of the population in each field, irrespective of radius. Assuming our fields are unbiased probes of the dominant stellar populations in these parts, we find that the M31 outer halo remains considerably more metal rich than that of the Milky Way out to at least 60 kpc. [source] New multiply-lensed galaxies identified in ACS/NIC3 observations of Cl0024+1654 using an improved mass modelMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2009Adi Zitrin ABSTRACT We present an improved strong-lensing analysis of Cl0024+1654 (z= 0.39) using deep Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS)/NIC3 images, based on 33 multiply-lensed images of 11 background galaxies. These are found with a model that assumes mass approximately traces light, with a low-order expansion to allow for flexibility on large scales. The model is constrained initially by the well-known five-image system (z= 1.675) and refined as new multiply-lensed systems are identified using the model. Photometric redshifts of these new systems are then used to constrain better the mass profile by adopting the standard cosmological relation between redshift and lensing distance. Our model requires only six free parameters to describe well all positional and redshift data. The resulting inner mass profile has a slope of d log M/d log r,,0.55, consistent with new weak-lensing measurements where the data overlap, at r, 200 kpc/h70. The combined profile is well fitted by a high-concentration Navarro, Frenk & White (NFW) mass profile, Cvir, 8.6 ± 1.6, similar to other well-studied clusters, but larger than predicted with standard , cold dark matter (,CDM). A well-defined radial critical curve is generated by the model and is clearly observed at r, 12 arcsec, outlined by elongated images pointing towards the centre of mass. The relative fluxes of the multiply-lensed images are found to agree well with the modelled magnifications, providing an independent consistency check. [source] The stellar population content of the thick disc and halo of the Milky Way analogue NGC 891MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2009M. Rejkuba ABSTRACT We present deep VI images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope, covering three fields in the north-east side of the edge-on disc galaxy NGC 891. The observed fields span a wide range of galactocentric distances along the eastern minor axis, extending from the plane of the disc to 12 kpc, and out to ,25 kpc along the major axis. The photometry of individual stars reaches ,2.5 mag below the tip of the red giant branch. We use the astrophotometric catalogue to probe the stellar content and metallicity distribution across the thick disc and spheroid of NGC 891. The colour,magnitude diagrams of thick disc and spheroid population are dominated by old red giant branch stars with a wide range of metallicities, from the sparsely populated metal-poor tail at [Fe/H],,2.4 dex, up to about half-solar metallicity. The peak of the metallicity distribution function of the thick disc is at ,0.9 dex. The inner parts of the thick disc, within ,14 kpc along the major axis show no vertical colour/metallicity gradient. In the outer parts, a mild vertical gradient of ,(V,I)0/,|Z| = 0.1 ± 0.05 kpc,1 or less than 0.1 dex kpc,1 is detected, with bluer colours or more metal-poor stars at larger distances from the plane. This gradient is, however, accounted for by the mixing with the metal-poor halo stars. No metallicity gradient along the major axis is present for thick-disc stars, but strong variations of about 0.35 dex around the mean of [Fe/H]=,1.13 dex are found. The properties of the asymmetric metallicity distribution functions of the thick-disc stars show no significant changes in both the radial and the vertical directions. The stellar populations situated within the solar-cylinder-like distances show strikingly different properties from those of the Galaxy populating similar distances. This suggests that the accretion histories of both galaxies have been different. The spheroid population, composed of the inner spheroid and the halo, shows remarkably uniform stellar population properties. The median metallicity of the halo stellar population shows a shallow gradient from about ,1.15 dex in the inner parts to ,1.27 dex at 24 kpc distance from the centre, corresponding to ,13reff. Similar to the thick-disc stars, large variations around the mean relation are present. [source] Spitzer IRAC infrared colours of submillimetre-bright galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008Min S. Yun ABSTRACT High-redshift submillimetre-bright galaxies identified by blank field surveys at millimetre and submillimetre wavelengths appear in the region of the Infra Red Array Camera (IRAC) colour,colour diagrams previously identified as the domain of luminous active galactic nuclei (AGNs). Our analysis using a set of empirical and theoretical dusty starburst spectral energy distribution (SED) models shows that power-law continuum sources associated with hot dust heated by young (,100 Myr old), extreme starbursts at z > 2 also occupy the same general area as AGNs in the IRAC colour,colour plots. A detailed comparison of the IRAC colours and SEDs demonstrates that the two populations are distinct from each other, with submillimetre-bright galaxies having a systematically flatter IRAC spectrum (,1 mag bluer in the observed [4.5],[8.0] colour). Only about 20 per cent of the objects overlap in the colour,colour plots, and this low fraction suggests that submillimetre galaxies powered by a dust-obscured AGN are not common. The red infrared colours of the submillimetre galaxies are distinct from those of the ubiquitous foreground IRAC sources, and we propose a set of infrared colour selection criteria for identifying SMG counterparts that can be used even in the absence of radio or Multiband Imaging Photometer for Spitzer (MIPS) 24 ,m data. [source] Evolution in the discs and bulges of group galaxies since z= 0.4MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2008Sean L. McGee ABSTRACT We present quantitative morphology measurements of a sample of optically selected group galaxies at 0.3 < z < 0.55 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and the gim2d surface brightness fitting software package. The group sample is derived from the Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2) and follow-up Magellan spectroscopy. We compare these measurements to a similarly selected group sample from the Millennium Galaxy Catalogue (MGC) at 0.05 < z < 0.12. We find that, at both epochs, the group and field fractional bulge luminosity (B/T) distributions differ significantly, with the dominant difference being a deficit of disc-dominated (B/T < 0.2) galaxies in the group samples. At fixed luminosity, z= 0.4 groups have ,5.5 ± 2 per cent fewer disc-dominated galaxies than the field, while by z= 0.1 this difference has increased to ,19 ± 6 per cent. Despite the morphological evolution we see no evidence that the group environment is actively perturbing or otherwise affecting the entire existing disc population. At both redshifts, the discs of group galaxies have similar scaling relations and show similar median asymmetries as the discs of field galaxies. We do find evidence that the fraction of highly asymmetric, bulge-dominated galaxies is 6 ± 3 per cent higher in groups than in the field, suggesting there may be enhanced merging in group environments. We replicate our group samples at z= 0.4 and 0 using the semi-analytic galaxy catalogues of Bower et al. This model accurately reproduces the B/T distributions of the group and field at z= 0.1. However, the model does not reproduce our finding that the deficit of discs in groups has increased significantly since z= 0.4. [source] Deep spectroscopy of the FUV,optical emission lines from a sample of radio galaxies at z, 2.5: metallicity and ionization,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008A. Humphrey ABSTRACT We present long-slit near-infrared (NIR) spectra, obtained using the Infrared Spectrometer And Array Camera (ISAAC) instrument at the Very Large Telescope, which sample the rest-frame optical emission lines from nine radio galaxies at z, 2.5. One-dimensional spectra have been extracted and, using broad-band photometry, have been cross-calibrated with spectra from the literature to produce line spectra spanning a rest wavelength of ,1200,7000 Å. The resulting line spectra have a spectral coverage that is unprecedented for radio galaxies at any redshift. We have also produced a composite of the rest-frame ultraviolet (UV),optical line fluxes of powerful, z, 2.5 radio galaxies. We have investigated the relative strengths of Ly,, H,, H,, He ii,1640 and He ii,4687, and we find that Av can vary significantly from object to object. In addition, we have identified new line ratios to calculate electron temperature: [Ne v],1575/[Ne v],3426, [Ne iv],1602/[Ne iv],2423, O iii],1663/[O iii],5008 and [O ii],2471/[O ii],3728. We calculate an average O iii temperature of 14100+1000,600 K. We have modelled the rich emission line spectra, and we conclude that they are best explained by active galactic nucleus (AGN) photoionization with the ionization parameter U varying between objects. For shock models (with or without the precursor) to provide a satisfactory explanation for the data, an additional source of ionizing photons is required , presumably the ionizing radiation field of the AGN. Single slab photoionization models are unable to reproduce the high- and the low-ionization lines simultaneously: the higher ionization lines imply higher U than do the lower ionization lines. This problem may be alleviated either by combining two or more single slab photoionization models with different U, or by using mixed-medium models such as those of Binette, Wilson & Storchi-Bergmann. In either case, U must vary from object to object. On the basis of N v/N iv] and N iv]/C iv we argue that, while photoionization is the dominant ionization mechanism in the extended emission line regions (EELR), shocks make a fractional contribution (,10 per cent) to its ionization. The N v/N iv] and N iv]/C iv ratios in the broad-line region (BLR) of some quasars suggest that shock ionization may be important in the BLR also. We find that in the EELR of z, 2 radio galaxies the N/H abundance ratio is close to its solar value. We conclude that N/H and metallicity do not vary by more than a factor of 2 in our sample. These results are consistent with the idea that the massive ellipticals which become the hosts to powerful AGN are assembled very early in the history of the universe, and then evolve relatively passively up to the present day. [source] The UKIRT Infrared Deep Sky Survey (UKIDSS)MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007A. Lawrence ABSTRACT We describe the goals, design, implementation, and initial progress of the UKIRT Infrared Deep Sky Survey (UKIDSS), a seven-year sky survey which began in 2005 May. UKIDSS is being carried out using the UKIRT Wide Field Camera (WFCAM), which has the largest étendue of any infrared astronomical instrument to date. It is a portfolio of five survey components covering various combinations of the filter set ZYJHK and H2. The Large Area Survey, the Galactic Clusters Survey, and the Galactic Plane Survey cover approximately 7000 deg2 to a depth of K, 18; the Deep Extragalactic Survey covers 35 deg2 to K, 21, and the Ultra Deep Survey covers 0.77 deg2 to K, 23. Summed together UKIDSS is 12 times larger in effective volume than the 2MASS survey. The prime aim of UKIDSS is to provide a long-term astronomical legacy data base; the design is, however, driven by a series of specific goals , for example, to find the nearest and faintest substellar objects, to discover Population II brown dwarfs, if they exist, to determine the substellar mass function, to break the z= 7 quasar barrier; to determine the epoch of re-ionization, to measure the growth of structure from z= 3 to the present day, to determine the epoch of spheroid formation, and to map the Milky Way through the dust, to several kpc. The survey data are being uniformly processed. Images and catalogues are being made available through a fully queryable user interface , the WFCAM Science Archive (http://surveys.roe.ac.uk/wsa). The data are being released in stages. The data are immediately public to astronomers in all ESO member states, and available to the world after 18 months. Before the formal survey began, UKIRT and the UKIDSS consortia collaborated in obtaining and analysing a series of small science verification (SV) projects to complete the commissioning of the camera. We show some results from these SV projects in order to demonstrate the likely power of the eventual complete survey. Finally, using the data from the First Data Release, we assess how well UKIDSS is meeting its design targets so far. [source] The first appearance of the red sequence of galaxies in proto-clusters at 2 ,z, 3MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Tadayuki Kodama ABSTRACT We explore the evolved galaxy population in the proto-clusters around four high- z radio galaxies at 2 ,z, 3 based on wide-field near-infrared (NIR) imaging. Three of the four fields are known proto-clusters as demonstrated by overdensities of line-emitting galaxies at the same redshifts as the radio galaxies found by narrow-band surveys and spectroscopic follow-up observations. We imaged the fields of three targets (PKS 1138,262, USS 0943,242 and MRC 0316,257) to a depth of Ks, 22 (Vega magnitude, 5,) over a 4 × 7 arcmin2 area centred on the radio galaxies with a new wide-field NIR camera, Multi-Object Infra-Red Camera and Spectrograph (MOIRCS), on the Subaru Telescope. Another target (USS 1558,003) was observed with Son of ISAAC on the New technology Telescope (NTT) to a depth of Ks= 20.5 (5,) over a 5 × 5 arcmin2 area. We apply colour cuts in J,Ks and/or JHKs in order to exclusively search for galaxies located at high redshifts: z > 2. To the 5, limiting magnitudes, we see a significant excess of NIR-selected galaxies by a factor of 2 to 3 compared to those found in the field of GOODS-South. The spatial distribution of these NIR-selected galaxies is not uniform and traces structures similar to those of emission-line galaxies, although the samples of NIR-selected galaxies and emitters show little overlap, from which we conclude that the former tend to be an evolved population with much higher stellar mass than the latter, young and active emitters. We focus on the NIR colour,magnitude sequence of the evolved population and find that the bright-end (Mstars > 1011 M,) of the red sequence is well populated by z, 2 but much less so in the z, 3 proto-clusters. This may imply that the bright-end of the colour,magnitude sequence first appeared between z= 3 and 2, an era coinciding with the appearance of sub-mm galaxies and the peak of the cosmic star formation rate. Our observations show that during the same epoch, massive galaxies are forming in high-density environments by vigorous star formation and assembly. [source] Structural parameters of Mayall II = G1 in M31MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007J. Ma ABSTRACT Mayall II = G1 is one of the most luminous globular clusters (GCs) known in M31. New deep, high-resolution observations with the Advanced Camera for Surveys on the Hubble Space Telescope are used to provide accurate photometric data to the smallest radii yet. In particular, we present the precise variation of ellipticity and position angle, and of surface brightness for the core of the object. Based on these accurate photometric data, we redetermine the structural parameters of G1 by fitting a single-mass isotropic King model. We derive a core radius, rc= 0.21 ± 0.01 arcsec (= 0.78 ± 0.04 pc), a tidal radius, rt= 21.8 ± 1.1 arcsec (= 80.7 ± 3.9 pc), and a concentration index c= log (rt/rc) = 2.01 ± 0.02. The central surface brightness is 13.510 mag arcsec,2. We also calculate the half-light radius, at rh= 1.73 ± 0.07 arcsec (= 6.5 ± 0.3 pc). The results show that, within 10 core radii, a King model fits the surface brightness distribution well. We find that this object falls in the same region of the MV versus log Rh diagram as , Centauri, M54 and NGC 2419 in the Milky Way. All three of these objects have been claimed to be the stripped cores of now defunct dwarf galaxies. We discuss in detail whether GCs, stripped cores of dwarf spheroidals and normal dwarf galaxies form a continuous distribution in the MV versus log Rh plane, or if GCs and dwarf spheroidals constitute distinct classes of objects; we present arguments in favour of this latter view. [source] Counting individual galaxies from deep 24-,m Spitzer surveysMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006G. Rodighiero ABSTRACT We address the question of how to deal with confusion-limited surveys in the mid-infrared (MIR) domain by using information from shorter-wavelength observations over the same sky regions. Such information, once applied to apparently extended MIR sources, which are indeed ,blends' of two or more different sources, allow us to disentangle the single counterparts and to split the measured flux density into different components. We present the application of this method to the 24-,m Spitzer archival data in the Great Observatories Origins Deep Survey ELAIS-N1 (GOODS EN1) test field, where apparently extended, ,blended' sources constitute about 20 per cent of a reliable sample of 983 sources detected above the 5, threshold down to 40 ,Jy. As a shorter-wavelength data set, we have considered the public Infrared Array Camera (IRAC) images and catalogues of the same field. We show that the 24-,m sample is almost unbiased down to ,40 ,Jy and the careful application of the deblending procedure does not require any statistical completeness correction (at least at the flux level considered). This is probed by direct comparison of our results with results in the literature that analysed the same data set through extensive Monte Carlo simulations. The extrapolation of the source counts down to fainter fluxes suggests that our 24-,m sample is able to resolve ,62 per cent of the cosmic background down to a flux level of 38 ,Jy. [source] Seasonal evolution of Titan's dark polar hood: midsummer disappearance observed by the Hubble Space TelescopeMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006Ralph D. Lorenz ABSTRACT Titan, Saturn's largest moon, has a dense organic-laden atmosphere that displays dramatic seasonal variations in composition and appearance. Here we document the evolution of the dark polar hood, first seen in 1980 by Voyager 1 around the north pole, and report quantitative measurements of the hood's disappearance from the south pole in 2002,2003 using previously unpublished observations with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). These data support a model of the hood as a transient structure associated with downwelling during polar winter. [source] Constraints on the initial mass function of the first starsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2006Raffaella Schneider ABSTRACT Motivated by theoretical predictions that the first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop II/I stars by means of a numerically generated catalogue of dark matter haloes coupled with a self-consistent treatment of chemical and radiative feedback. Depending on the strength of the chemical feedback, Pop III stars can contribute a substantial fraction (several per cent) of the cosmic star formation activity even at moderate redshifts, z, 5. We find that the three z, 10 sources tentatively detected in Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Ultra Deep Fields (UDFs) should be powered by Pop III stars, if these are massive; however, this scenario fails to reproduce the derived Wilkinson Microwave Anisotropy Probe (WMAP) electron scattering optical depth. Instead, both the UDFs and WMAP constraints can be fulfilled if stars at any time form with a more standard, slightly top-heavy, Larson initial mass function. [source] A star-forming galaxy at z= 5.78 in the Chandra Deep Field SouthMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2003Andrew J. Bunker ABSTRACT We report the discovery of a luminous z= 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an ,i -drop' from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (i,,z,)AB= 1.6 indicated a spectral break consistent with the Lyman , forest absorption shortward of Lyman , at z, 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rhl < 0.5 h,170 kpc). We have obtained a deep (5.5 h) spectrum of this z,AB= 24.7 galaxy with the DEIMOS optical spectrograph on the Keck Telescope, and here we report the discovery of a single emission line centred on 8245 Å detected at 20, with a flux of f, 2 × 10,17 erg cm,2 s,1. The line is clearly resolved with detectable structure at our resolution of better than 55 km s,1, and the only plausible interpretation consistent with the ACS photometry is that we are seeing Lyman , emission from a z= 5.78 galaxy. This is the highest redshift galaxy to be discovered and studied using HST data. The velocity width (,vFWHM= 260 km s,1) and rest-frame equivalent width (WLy,rest= 20 Å) indicate that this line is most probably powered by star formation, as an AGN would typically have larger values. The starburst interpretation is supported by our non-detection of the high-ionization N v,1240- Å emission line, and the absence of this source from the deep Chandra X-ray images. The star formation rate inferred from the rest-frame UV continuum is 34 h,270 M, yr,1 (,M= 0.3, ,,= 0.7). This is the most luminous starburst known at z > 5. Our spectroscopic redshift for this object confirms the validity of the i,-drop technique of Stanway et al. to select star-forming galaxies atz, 6. [source] Hubble Space Telescope Wide Field Planetary Camera 2 observations of hyperluminous infrared galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2002D. Farrah We present Hubble Space Telescope Wide Field Planetary Camera 2 I -band imaging for a sample of nine hyperluminous infrared galaxies (HLIRGs) spanning a redshift range . Three of the sample have morphologies showing evidence for interactions and six are quasi-stellar objects (QSOs). Host galaxies in the QSOs are detected reliably out to . The detected QSO host galaxies have an elliptical morphology with scalelengths spanning and absolute k -corrected magnitudes spanning There is no clear correlation between the infrared (IR) power source and the optical morphology. None of the sources in the sample, including F15307+3252, shows any evidence for gravitational lensing. We infer that the IR luminosities are thus real. Based on these results, and previous studies of HLIRGs, we conclude that this class of object is broadly consistent with being a simple extrapolation of the ULIRG population to higher luminosities; ULIRGs being mainly violently interacting systems powered by starbursts and/or active galactic nuclei. Only a small number of sources, the infrared luminosities of which exceed 1013 L,, are intrinsically less luminous objects that have been boosted by gravitational lensing. [source] H i kinematics in a massive spiral galaxy at z= 0.89MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2005L. V. E. Koopmans ABSTRACT We present a kinematic model of the neutral hydrogen in the spiral galaxy of the lens system PKS 1830,211, based on a Multi-Element Radio-Linked Interferometer Network (MERLIN) 1.4-GHz radio map and the integrated and redshifted 21-cm hydrogen absorption-line profile as measured with the Westerbork Synthesis Radio Telescope (WSRT). Degeneracies in the models do not allow a unique determination of the kinematic centre, and forthcoming deeper Hubble Space Telescope observations with the Advanced Camera for Surveys (ACS) are required to break this degeneracy. Even so, we measure the inclination of the hydrogen disc: i= 17°,32°, indicating a close to face-on spiral galaxy. The optical depth increases with radius over the extent of the Einstein ring, suggesting H i depletion towards the lens centre. The latter could be due to star formation or conversion of H i into molecular hydrogen because of a higher metalicity/dust content in the galaxy centre. The neutral hydrogen optical depth gives NH I= 2 × 1021 cm,2 at r= 5.0 h,170 kpc in the disc (Ts= 100 K), comparable to local spiral galaxies. [source] IR spectroscopy of COmosphere dynamics with the CO ?rst overtone bandASTRONOMISCHE NACHRICHTEN, Issue 6 2010T.A. Schad Abstract We discuss observations of the weak ?rst overtone (,, = 2) CO absorption band near 2300 nm with the U.S. National Solar Observatory Array Camera (NAC), a modern mid-infrared detector. This molecular band provides a thermal diagnostic that forms lower in the atmosphere than the stronger fundamental band near 4600 nm. The observed center-to-limb increase in CO line width qualitatively agrees with the proposed higher temperature shocks or faster plasma motions higher in the COmosphere. The spatial extent of chromospheric shock waves is currently at or below the diffraction limit of the available CO lines at existing telescopes. Five minute period oscillations in line strength and measured Doppler shifts are consistent with the p-mode excitation of the photospheric gas. We also show recent efforts at direct imaging at 4600 nm. We stress that future large-aperture solar telescopes must be teamed with improved, dynamic mid-infrared instruments, like the NAC, to capitalize on the features that motivate such facilities (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The evolution of cluster dwarfsASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009D. Harsono Abstract We summarize the results from analyzing six clusters of galaxies at 0.14 < z < 0.40 observed with the Hubble Space Telescope Advanced Camera for Surveys. We derive deep composite luminosity functions in B, g, V, r, i, and z down to absolute magnitude of , ,14 + 5 log h mag. The luminosity functions are fitted by a single Schechter function with MBgVriz * = ,19.8, ,20.9, ,21.9, ,22.0, ,21.7, and ,22.3 mag, and , , ,1.3 for all bands. The data suggests red sequence dominates the luminosity function down to ,6 mag below L*, the dwarf spheroidals regime. Hence, at least at z 0.3, the red sequence is well established and galaxies down to dwarf spheroidals are assembled within these clusters. We do not detect the faint-end upturn (M > ,16) that is observed in lower redshift clusters. If this is real, the faint-end population has originated since z = 0.3 (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Dwarf spheroidal galaxies in the M81 group of galaxiesASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009S. Lianou Abstract We study the properties of the dwarf galaxy population in the nearby interacting M81 group of galaxies. In particular, we are deriving the metallicity distribution functions, the ages and the star formation histories of these dwarf galaxies based on data from the Hubble Space Telescope's Advanced Camera for Surveys and the Sloan Digital Sky Survey. We are correlating this information with the dwarf galaxies' position in the group in order to derive the impact of interactions and environment on their evolution. Here we present preliminary results on the metallicity distribution functions of dwarf spheroidals in the M81 group (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] CTK: A new CCD Camera at the University Observatory Jena,ASTRONOMISCHE NACHRICHTEN, Issue 5 2009M. Mugrauer Abstract The Cassegrain-Teleskop-Kamera (CTK) is a new CCD imager which is operated at the University Observatory Jena since begin of 2006. This article describes the main characteristics of the new camera. The properties of the CCD detector, the CTK image quality, as well as its detection limits for all filters are presented (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Optical flares from the faint mid-dM star 2MASS J00453912+4140395ASTRONOMISCHE NACHRICHTEN, Issue 9 2007Zs. K Abstract We present B and V light curves of a large stellar flare obtained with the Wide Field Camera at the Isaac Newton 2.5-m telescope (La Palma). The source object is a faint (mV = 21.38) foreground star in the field of the Andromeda galaxy, with its most probable spectral type being dM4. We provide an estimate of the total flare energy in the optical range and find it to be of the order of 1035 erg. The cooling phase of the large flare shows three additional weak flare-like events, which we interpret as results of a triggering mechanism also observed on the Sun during large coronal mass ejections. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mid-Infrared Imaging and Spectroscopic Observations of the Galactic Center with Subaru/COMICSASTRONOMISCHE NACHRICHTEN, Issue S1 2003Y. Okada Abstract We report the results of mid-infrared (7.8,m,13.2 ,m) high-spatial resolution imaging and spectroscopic observations of the Galactic center region with the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru telescope. The images clearly show bright infrared sources and small structures in the diffuse emission. The spectra of all the observed positions show the 9.7 ,m silicate absorption feature. After corrected for the empirically-derived extinction, the intrinsic spectra of the infrared sources show either strong silicate emission or absorption, while the intrinsic diffuse emission has a power-law type spectrum. This difference indicates a possibility of dust processing due to the interaction between the infrared sources and their surrounding medium or a different origin of the dust grains surrounding the sources from those in the diffuse region. [source] Technologies of Visibility: The Utopian Politics of Cameras, Televisions, Videos and Dreams in New BritainTHE AUSTRALIAN JOURNAL OF ANTHROPOLOGY, Issue 1 2006Andrew Lattas This paper explores how Melanesian villagers have harnessed modern, technological ways of seeing. It begins by analysing the politics and narrative structures of dreams and popular stories about secret photos concerning the dead. These are stories about losing control and regaining hidden, alternative representations of Melanesians. I then analyse how millenarian followers have experimented with ,constructing' their own versions of cameras, televisions and videos so as to gain access to the omniscient powers of modern technology and merge them with those of a Christian god and with the gaze of the dead. In the Pomio Kivung movement, ,televisions' and ,videos' have even been used to create new forms of moral surveillance for policing and governing communities. Here the customary shamanic worlds of dreams and possession have been modernised and redeployed to re-mediate the governmental practices and disciplinary schemes of civilisating projects originally belonging to Western churches and government. [source] Small Format Digital Cameras for Aerial Survey: Where Are We Now?THE PHOTOGRAMMETRIC RECORD, Issue 96 2000R. W. Graham This paper introduces the subject of digital sensors for aerial survey by reviewing the use made of small format digital cameras in such an application. The major advantages and disadvantages of employing such consumer technology for aerial survey are highlighted. Finally, a specification is proposed for a minimum requirement for a digital solution based on a single area array sensor. [source] As-consistent-As-possible compositing of virtual objects and video sequencesCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2006Guofeng Zhang Abstract We present an efficient approach that merges the virtual objects into video sequences taken by a freely moving camera in a realistic manner. The composition is visually and geometrically consistent through three main steps. First, a robust camera tracking algorithm based on key frames is proposed, which precisely recovers the focal length with a novel multi-frame strategy. Next, the concerned 3D models of the real scenes are reconstructed by means of an extended multi-baseline algorithm. Finally, the virtual objects in the form of 3D models are integrated into the real scenes, with special cares on the interaction consistency including shadow casting, occlusions, and object animation. A variety of experiments have been implemented, which demonstrate the robustness and efficiency of our approach. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||