Detection of Massive Forming Galaxies at Redshifts Greater than One

The complex problem of when and how galaxies formed has not until recently been susceptible of direct attack. It has been known for some time that the excessive number of blue galaxies counted at faint magnitudes implies that a considerable fraction of the massive star formation in the universe occurred at z < 3, but, surprisingly, spectroscopic studies of galaxies down to a B magnitude of 24 found little sign of the expected high-z progenitors of current massive galaxies, but rather, in large part, small blue galaxies at modest redshifts z \sim 0.3. This unexpected population has diverted attention from the possibility that early massive star-forming galaxies might also be found in the faint blue excess. From KECK spectroscopic observations deep enough to encompass a large population of z > 1 field galaxies, we can now show directly that in fact these forming galaxies are present in substantial numbers at B \sim 24, and that the era from redshifts 1 to 2 was clearly a major period of galaxy formation. These z > 1 galaxies have very unusual morphologies as seen in deep HST WFPC2 images.Comment: 10 pages LaTeX + 5 PostScript figures in uuencoded gzipped tar file; aasms4.sty, flushrt.sty, overcite.sty (the two aastex4.0 and overcite.sty macros are available from xxx.lanl.gov) Also available (along with style files) via anonymous ftp to ftp://hubble.ifa.hawaii.edu/pub/preprints . E-print version of paper adds citation cross-references to other archived e-prints, where available. To appear in Nature October 19, 199

The luminosity function of field galaxies

Schmidt's method for construction of luminosity function of galaxies is generalized by taking into account the dependence of density of galaxies from the distance in the near Universe. The logarithmical luminosity function (LLF) of field galaxies depending on morphological type is constructed. We show that the LLF for all galaxies, and also separately for elliptical and lenticular galaxies can be presented by Schechter function in narrow area of absolute magnitudes. The LLF of spiral galaxies was presented by Schechter function for enough wide area of absolute magnitudes: . Spiral galaxies differ slightly by parameter . At transition from early spirals to the late spirals parameter in Schechter function is reduced. The reduction of mean luminosity of galaxies is observed at transition from elliptical galaxies to lenticular galaxies, to early spiral galaxies, and further, to late spiral galaxies, in a bright end, . The completeness and the average density of samples of galaxies of different morphological types are estimated. In the range the mean number density of all galaxies is equal 0.127 Mpc-3.Comment: 14 page, 8 figures, to appear in Astrophysic

The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

The Wide-field Spectroscopic Telescope (WST) Science White Paper

The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat

The peculiar motions of early-type galaxies in two distant regions - III. The photometric data

We present R-band CCD photometry for 776 galaxies observed in the EFAR project. The photometry is compared with photoelectric data, showing that a common zero-point good to better than 1 per cent and a precision of 0.03 mag per zero-point have been achieved. We give the circularly averaged surface brightness profiles and the photometric parameters of the 762 programme galaxies, D n diameters (at 20.5 mag arcsec -2), half-luminosity radii R e, total magnitudes m T and average effective surface brightnesses 〈SB e〉. The photometric parameters are derived using the seeing-convolved, R 1/4-plus-exponential fitting algorithm described in Paper IV which optimally combines multiple profiles and corrects for sky subtraction errors. The parameters of the two-component fits are also given. We find that the diameters D n span the range 4.8-90 arcsec, with 〈logD n〉 = 1.30 or 20 arcsec. The run of the effective radii R e is 1.6-71.2 arcsec, with 〈log R e〉 = 0.84 or 6.9 arcsec. The total magnitudes m T extend from 10.57 to 15.97 mag, with a mean of 13.85 mag. The effective surface brightnesses 〈SB e〉 span the range 17.78-22.35 mag arcsec -2 with a mean of 19.89 mag arcsec -2. The mean photometric precisions of D n diameters, magnitudes and surface brightnesses are 0.9 per cent, 0.017 mag and 0.017 mag arcsec -2 respectively. In addition, the fitting scheme quantifies and minimizes the many systematic biases affecting the determination of galaxy photometric parameters. We find simple R 1/4 fits for only 14 per cent of the total, and simple exponential fits for ≉ 1 per cent of the total. The spread in sky values measured from the different profiles of the same object is less than 1 per cent in 85 per cent of the cases. In 80 per cent of the fits a reduced χ 2 of less than 12 is obtained. More than 90 per cent of the galaxies have at least one profile extending to more than 4 half-luminosity radii. More than 90 per cent of the galaxies are well resolved, having at least one profile where R e > 2Γ, where Γ is the FWHM of the point-spread function. More than 80 per cent of the profiles have a global signal-to-noise ratio larger than 300. The extrapolation needed to derive total magnitudes is less than 10 per cent for 80 per cent of the fits. More than 80 per cent of the galaxies have mean effective surface brightness larger than the observed sky brightness. In 90 per cent of the profiles the estimate of the contamination of the sky by the galaxy light is less than 1 per cent. Summarizing, the extensive internal comparisons, together with Monte Carlo simulations (see Paper IV), show that we derive total magnitudes and half-luminosity radii to better than 0.15 mag and 25 per cent respectively for 90 per cent of our sample. In contrast, external comparisons show that data in the literature can be strongly affected by systematic errors due to large extrapolations, small radial range, sky subtraction errors, seeing effects, and the use of a simple R 1/4 fit. The resulting errors can easily amount to more than 0.5 mag in the total magnitudes and 50 per cent in the half-luminosity radii. The errors on the combined quantity FP = log R e - 0.3 〈SB e〉 which enters the Fundamental Plane equation remain, however, always smaller than 0.03 dex. The galaxy type classification, based on all of the information available to us, shows that 31 per cent of the sample objects, visually selected from photographic images to be of early type, are in fact spiral or barred galaxies. The 69 per cent of galaxies classified as early-type can be subdivided into cD (8 per cent), E (12 per cent with a simple R 1/4 law best fit), and E/S0 (48 per cent with a disc-plus-bulge best fit). The photographic diameters D W measured in Paper I correlate with D n diameters or, equivalently, with the Fundamental Plane quantity FP = log R e - 0.3 〈SB e〉, with 23 per cent scatter for the early-type sample. © 1997 RAS