Deg2 Area Research Articles

Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected density across the sky. These mass provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing map reconstructed from shear measurements in a 139 deg2 area from the Dark Energy Survey (DES) science verification data. We compare the distribution of with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclusters and voids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N -body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8 sigma level with 20 arcminute smoothing. We find that the contribution of systematics to the lensing maps is generally within measurement uncertainties. In this work, we analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger data sets from the survey.

INTERSTELLAR EXTINCTION IN THE DIRECTION OF THE OPEN CLUSTER M29

The interstellar extinction is investigated in a 1.5 deg2 area in the direction of the open cluster M29 (NGC 6913) in Cygnus, centered at R.A. = 20h 24m, decl. = +38° 30′. The study is based on photometric classification of 1110 stars in spectral and luminosity classes down to V = 19 mag using photometry in the Vilnius seven-color system published in Paper I (Milasius et al. 2013). Additionally, in the same area the extinction is investigated using 1147 red clump giants (RCGs), identified by combining selected two-color diagrams of the 2MASS and Spitzer surveys. The investigated area is divided into three parts with different obscuration and in these directions the extinction versus distance plots up to 5 kpc are presented. In the whole area a steep rise of the extinction is observed at a distance of ∼800 pc; it should be related to dust clouds in the Great Cygnus Rift obscuring the stars behind it by AV = 4.0–4.7 mag. RCGs exhibit much larger extinction values, up to = 1.2–1.3 mag in the more transparent areas and 1.45 mag in the northeastern part of the area and above it, where the dust cloud TGU H466 is located. These values of correspond to AV = 10–12 mag. We do not exclude the possibility that the largest values of the extinction belong not to RCGs but to some contaminating intrinsically red AGB stars penetrated through the applied RCG selection constraints. The extinction in the TGU H466 cloud probably originates in two cloud systems—the Great Cygnus Rift at 800 pc and the Cygnus X complex of dust and molecular clouds at 1.3–1.5 kpc.

J - AND H -BAND IMAGING OF AKARI NORTH ECLIPTIC POLE SURVEY FIELD

We present the J and H-band source catalog covering the AKARI North Ecliptic Pole field. Filling the gap between the optical data from other follow-up observations and mid-infrared (MIR) data from AKARI, our near-infrared (NIR) data provides contiguous wavelength coverage from optical to MIR. For the J and H-band imaging, we used the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer (FLAMINGOS) on the Kitt Peak National Observatory 2.1m telescope covering a 5.1 deg2 area down to a 5 sigma depth of ~21.6 mag and ~21.3 mag (AB) for J and H-band with an astrometric accuracy of 0.14" and 0.17" for 1 sigma in R.A. and Decl. directions, respectively. We detected 208,020 sources for J-band and 203,832 sources for H-band. This NIR data is being used for studies including analysis of the physical properties of infrared sources such as stellar mass and photometric redshifts, and will be a valuable dataset for various future missions.

Fungos micorrízicos arbusculares como indicadores da recuperação de áreas degradadas no nordeste do Brasil

Avaliaram-se atributos dos fungos micorrízicos arbusculares (FMAs) na região sob desertificação de Gilbués, PI, Brasil, objetivando monitorar áreas sob diferentes níveis de degradação e recuperação do solo. Amostras de solo foram coletadas na camada de 0-0,2 m, durante o período seco de 2009 em quatro áreas pertencentes a um Argissolo, visualmente definidas como: REC - área em recuperação por contenção da erosão e plantio de gramíneas e leguminosas exóticas; DEG- área altamente degradada; IDEG - área moderadamente degradada; MN - área de vegetação nativa. Foram analisados a colonização radicular, o número mais provável de propágulos infectivos (NMP), índices de diversidade (Shannon-Wiener, diversidade e dominância de Simpson, equitabilidade de Pielou e Margalef) e os atributos químicos do solo pH, H+Al, fósforo e matéria orgânica, usados como variáveis explicativas da variabilidade de atributos dos FMAs por meio de análises multivariadas. A colonização radicular e o NMP de propágulos foram superiores em REC. Os índices de Shannon-Wiener, dominância de Simpson e Margalef foram menores na área DEG, demonstrando serem bons indicadores de alterações na comunidade de FMAs em áreas degradadas. Pela análise de agrupamento hierárquico, a área DEG teve maior dissimilaridade em relação às demais. Pela análise por componentes principais, os índices de Shannon-Wiener, Margalef, de Simpson, a dominância de Simpson e os teores de fósforo foram os parâmetros que mais explicaram a variância total.

The North Ecliptic Pole Wide survey of AKARI: a near- and mid-infrared source catalog

We present a photometric catalog of infrared (IR) sources based on the North Ecliptic PoleWide field (NEP-Wide) survey of AKARI, which is an infrared space telescope launched by Japan. The NEP-Wide survey covered 5.4 deg2 area, a nearly circular shape centered on the North Ecliptic Pole, using nine photometric filter-bands from 2 - 25 {\mu}m of the Infrared Camera (IRC). Extensive efforts were made to reduce possible false objects due to cosmic ray hits, multiplexer bleeding phenomena around bright sources, and other artifacts. The number of detected sources varied depending on the filter band: with about 109,000 sources being cataloged in the near-IR bands at 2 - 5 {\mu}m, about 20,000 sources in the shorter parts of the mid-IR bands between 7 - 11 {\mu}m, and about 16,000 sources in the longer parts of the mid-IR bands, with \sim 4,000 sources at 24 {\mu}m. The estimated 5? detection limits are approximately 21 magnitude (mag) in the 2 - 5 {\mu}m bands, 19.5 - 19 mag in the 7 - 11 {\mu}m, and 18.8 - 18.5 mag in the 15 - 24 {\mu}m bands in the AB magnitude scale. The completenesses for those bands were evaluated as a function of magnitude: the 50% completeness limits are about 19.8 mag at 3 {\mu}m, 18.6 mag at 9 {\mu}m, and 18 mag at 18 {\mu}m band, respectively. To construct a reliable source catalog, all of the detected sources were examined by matching them with those in other wavelength data, including optical and ground-based near-IR bands. The final band-merged catalog contains about 114,800 sources detected in the IRC filter bands. The properties of the sources are presented in terms of the distributions in various color-color diagrams.

Millimeter imaging of submillimeter galaxies in the COSMOS field: redshift distribution

We present new IRAM PdBI 1.3mm continuum observations at ~1.5" resolution of 28 SMGs previously discovered with the 870um bolometer LABOCA at APEX within the central 0.7deg2 of the COSMOS field. 19 out of the 28 LABOCA sources were detected with the PdBI at a >~3sigma level of ~1.4mJy/b. A combined analysis of this new sample with existing interferometrically identified SMGs in the COSMOS field yields the following results: 1) >~15%, and possibly up to ~40% of single-dish detected SMGs consist of multiple sources, 2) statistical identifications of multi-wavelength counterparts to the single-dish SMGs yield that only ~50% of these single-dish SMGs have real radio or IR counterparts, 3) ~18% of interferometric SMGs have only radio or even no multi-wavelength counterpart at all, and 4) ~50-70% of z>~3 SMGs have no radio counterparts down to an rms of 7-12uJy at 1.4GHz. Using the exact interferometric positions to identify proper multi-wavelength counterparts allows us to determine accurate photometric redshifts for these sources. The redshift distributions of the combined and the individual 1.1mm and 870um selected samples have a higher mean and broader width than the redshift distributions derived in previous studies. Our sample supports the previous tentative trend that on average brighter and/or mm-selected SMGs are located at higher redshifts. There is a tentative offset between the mean redshift for the 1.1mm (<z>=3.1+/-0.4) and 870um (<z>=2.6+/-0.4) selected samples, with the 1.1mm sources lying on average at higher redshifts. Based on our nearly complete sample of AzTEC 1.1mm SMGs within a uniform 0.15deg2 area we infer a higher surface density of z>~4 SMGs than predicted by current cosmological models. In summary, our findings imply that (sub-)millimeter interferometric identifications are crucial to build statistically complete and unbiased samples of SMGs.

AKARIINFRARED CAMERA SURVEY OF THE LARGE MAGELLANIC CLOUD. I. POINT-SOURCE CATALOG

We present a near- to mid-infrared point source catalog of 5 photometric bands at 3.2, 7, 11, 15 and 24 um for a 10 deg2 area of the Large Magellanic Cloud (LMC) obtained with the Infrared Camera (IRC) onboard the AKARI satellite. To cover the survey area the observations were carried out at 3 separate seasons from 2006 May to June, 2006 October to December, and 2007 March to July. The 10-sigma limiting magnitudes of the present survey are 17.9, 13.8, 12.4, 9.9, and 8.6 mag at 3.2, 7, 11, 15 and 24 um, respectively. The photometric accuracy is estimated to be about 0.1 mag at 3.2 um and 0.06--0.07 mag in the other bands. The position accuracy is 0.3" at 3.2, 7 and 11um and 1.0" at 15 and 24 um. The sensitivities at 3.2, 7, and 24 um are roughly comparable to those of the Spitzer SAGE LMC point source catalog, while the AKARI catalog provides the data at 11 and 15 um, covering the mid-infrared spectral range contiguously. Two types of catalog are provided: a Catalog and an Archive. The Archive contains all the detected sources, while the Catalog only includes the sources that have a counterpart in the Spitzer SAGE point source catalog. The Archive contains about 650,000, 140,000, 97,000, 43,000, and 52,000 sources at 3.2, 7, 11, 15, and 24 um, respectively. Based on the catalog, we discuss the luminosity functions at each band, the color-color diagram, and the color-magnitude diagram using the 3.2, 7, and 11 um band data. Stars without circumstellar envelopes, dusty C-rich and O-rich stars, young stellar objects, and background galaxies are located at distinct regions in the diagrams, suggesting that the present catalog is useful for the classification of objects towards the LMC.

PANORAMIC SURVEY OF Lyα EMITTERS ATz= 3.1

We present the results of the extensive narrowband survey of Lyα emission-line objects at z = 3.1 in the 1.38 deg2 area surrounding the high-density region of star-forming galaxies at z = 3.09 in the SSA22 field, as well as in the 1.04 deg2 area of the three separated general blank fields. In total, of 2161 Lyα emitters, there are 1394 in the SSA22 fields and 767 in the general fields detected at the narrowband AB magnitude limit of 25.73, which corresponds to the line flux of ≈1.8 × 10−17 erg s−1 cm−2 or the luminosity of ≈1.5 × 1042 erg s−1 at z = 3.1, above the observed equivalent-width threshold, ≈190 Å. The average surface number density of the emitters at z = 3.1 in the general fields above the thresholds is 0.20 ± 0.01 arcmin−2. The SSA22 high-density region at z = 3.09, whose peak local density is six times that of the average, is found to be the most prominent outstanding structure in the whole surveyed area and is firmly identified as a robust "protocluster." We also compared the overdensity of the 100 arcmin2 and 700 arcmin2 areas which contain the protocluster with the expected fluctuation of the dark matter as well as those of the model galaxies in cosmological simulations. We found that the peak height values of the overdensity are 8–10 and 3–4 times the expected standard deviations for the counts of Lyα emitters at z = 3.1 in the corresponding volume, respectively. We conclude that the structure at z = 3.09 in the SSA22 field is a very significant and rare density peak up to the scale of ≈60 Mpc.

The minimum effective shape feature for neurons in the macaque Anterior Intraparietal area

Event Abstract Back to Event The minimum effective shape feature for neurons in the macaque Anterior Intraparietal area Maria C. Romero1* and Peter Janssen1* 1 KULeuven, Laboratory for Neuro- and Psychofysiology, Belgium Neurons in the Anterior Intraparietal area (AIP) respond selectively to two-dimensional shapes and contours (Romero et al., 2012). In the present study we investigated the minimum effective shape features evoking selective responses in AIP of two rhesus monkeys using a stimulus reduction approach. The stimulus set in this reduction test consisted of contour shapes derived from images of real-world objects (full outlines; circumference ~16 deg), and line segments obtained by subdividing the full contours into 4, 8 and 16 segments (length 4, 2 and 1 deg, respectively). We first mapped the receptive field (RF) of every responsive AIP neuron with effective (preferred) and non-effective (nonpreferred) images of real-world objects (size 3 deg) presented in a 12 by 8 deg area around the fixation point during passive fixation. All stimuli in the reduction test were presented on the RF center, at their corresponding position in the original image. Almost all AIP neurons tested (47/48) responded significantly to at least one of the 4, 8 or 16-fragment stimuli obtained by reduction. We considered that a shape fragment was effective for the neuron if the response rate to the fragment was at least 50 % of their maximum response in the test. With this criterion, 83% (40/48) of our AIP cells responded to at least one of the 4-fragment stimuli, 88% (42/48) responded to at least one of the 8-fragment stimuli, and 75% (36/48) responded to at least one of the 16- fragment stimuli. However, the number of effective fragments for each cell was on average low, as most neurons (41/ 48; 85 %) were only responsive for less than 6 fragments in the test. A large majority of cells (41/48; 88%) responding to fragments in the preferred shape were also responsive to fragments derived from the nonpreferred shape. The RF mapping revealed a cluttered RF profile in a high proportion of AIP cells (33/48; 69%), with several local maxima and minima. Furthermore, the RF profile depended heavily on the stimulus used, as measured by the low 2D correlation between responses to the best 3 deg surface and the best fragment (average r = 0.36). The remaining AIP cells (15/48; 31%) showed localized, foveal RFs. Overall, our results demonstrate that for most AIP neurons the minimum effective shape feature consists of very small line fragments measuring merely 1 deg. The RF structure in AIP can be highly complex and depending on the stimulus used. Acknowledgements Supported by ERC-StG-260607, PFV10 ⁄ 008, GOA 10 ⁄ 19, FWO (G.0713.09). References Romero M.C., Van Dromme I., Janssen P. (2012) Responses to two-dimensional shapes in the macaque anterior intraparietal area. European Journal of Neuroscience, 36: 2324-2334. Keywords: Visual Neuroscience, shape, Parietal Lobe, Electrophysiology, monkey Conference: Belgian Brain Council, Liège, Belgium, 27 Oct - 27 Oct, 2012. Presentation Type: Poster Presentation Topic: Other basic/clinical neurosciences topic Citation: Romero MC and Janssen P (2012). The minimum effective shape feature for neurons in the macaque Anterior Intraparietal area. Conference Abstract: Belgian Brain Council. doi: 10.3389/conf.fnhum.2012.210.00109 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 21 Aug 2012; Published Online: 12 Sep 2012. * Correspondence: Dr. Maria C Romero, KULeuven, Laboratory for Neuro- and Psychofysiology, Leuven, 3000, Belgium, Maria.C.Romero@med.kuleuven.be Prof. Peter Janssen, KULeuven, Laboratory for Neuro- and Psychofysiology, Leuven, 3000, Belgium, Peter.Janssen@med.kuleuven.be Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Maria C Romero Peter Janssen Google Maria C Romero Peter Janssen Google Scholar Maria C Romero Peter Janssen PubMed Maria C Romero Peter Janssen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Tailed Radio Sources in the CDFS Field

Using 1.4 GHz ATCA & VLA images with 5.5 GHz ATCA data, we present a sample of 12 bent-tailed galaxies over the 4 deg2 area of the Chandra Deep Field South (CDFS). We find 10 new sources, one of which is possibly the highest red-shift bent-tailed galaxy detected at z ∼ 2.

EXTENDED STAR CLUSTERS IN THE REMOTE HALO OF THE INTRIGUING DWARF GALAXY NGC 6822

We present a study on four new star clusters discovered in the halo of the intriguing dwarf irregular galaxy NGC 6822 from a wide field survey covering 3 deg x 3 deg area carried out with MegaCam at Canada-France-Hawaii Telescope (CFHT). The star clusters have extended structures with half-light radii R_h ~ 7.5 -- 14.0 pc, larger than typical Galactic globular clusters and other known globular clusters in NGC 6822. The integrated colors and color magnitude diagrams (CMD) of resolved stars suggest that the new star clusters are 2 -- 10 Gyr old and relatively metal poor with Z=0.0001--0.004 based on the comparison with theoretical models. The projected distance of each star cluster from the galaxy center ranges from 10.7 arcmin (~ 1.5 kpc) to 77 arcmin (~ 11 kpc), far beyond the optical body of the galaxy. Interestingly, the new star clusters are aligned along the elongated old stellar halo of NGC 6822, which is almost perpendicular to the HI gas distribution where young stellar populations exist. We also find that the colors and half-light radii of the new clusters are correlated with the galactocentric distance: clusters farther from the galaxy center are larger and bluer than those closer to the galaxy center. We discuss the stellar structure and evolution of NGC 6822 implied by these new extended star clusters in the halo. We also discuss the current status of observational and theoretical understandings regarding the origin of extended star clusters in NGC 6822 and other galaxies.

Extending the RP survey to the outer LMC

AbstractWe are extending our search for faint PNe in the LMC to include the outer 56 deg2 area not covered in the original UKST survey of the central 25eg2 region. Candidate PNe have been selected using the Magellanic Cloud Emission Line Survey (MCELS) and the first round of observations has yielded 93 new LMC PNe while confirming the 102 previously known PNe in the outer LMC. We plan to continue our spectroscopic object identification program until we cover all our remaining candidates in the survey area. These observations, providing medium and high resolution spectra from λ3650Å to λ6900Å will additionally be used to measure fluxes for a series of research projects including luminosity functions, abundances and LMC kinematics.

Variability selected high-redshift quasars on SDSS Stripe 82

The SDSS-III BOSS Quasar survey will attempt to observe z > 2.15 quasars at a density of at least 15 per square degree to yield the first measurement of the baryon acoustic oscillations in the Ly-α forest. To help reaching this goal, we have developed a method to identify quasars based on their variability in the ugriz optical bands. The method has been applied to the selection of quasar targets in the SDSS region known as Stripe 82 (the southern equatorial stripe), where numerous photometric observations are available over a 10-year baseline. This area was observed by BOSS during September and October 2010. Only 8% of the objects selected via variability are not quasars, while 90% of the previously identified high-redshift quasar population is recovered. The method allows for a significant increase in the z > 2.15 quasar density over previous strategies based on optical (ugriz) colors, achieving a density of 24.0 deg-2 on average down to g ~ 22 over the 220 deg2 area of Stripe 82. We applied this method to simulated data from the Palomar Transient Factory and from Pan-STARRS, and showed that even with data that have sparser time sampling than what is available in Stripe 82, including variability in future quasar selection strategies would lead to increased target selection efficiency in the z > 2.15 redshift range. We also found that broad absorption line quasars are preferentially present in a variability than in a color selection.

A deep proper-motion survey of the nearby open cluster Blanco 1★†

We provide two comprehensive catalogues of positions and proper motions in the area of open cluster Blanco 1. The main catalogue, CtlgM, contains 6271 objects down to V similar to 18.5 and covers a circular similar to 11 deg2 area. The accuracy of CtlgM proper motions, at about 0.3-0.5 mas yr-1 for well-measured stars, permits an excellent segregation between the cluster and field stars. The vector-point diagram of proper motions indicates an estimated total of similar to 165 cluster members among the stars in our sample, while 314 stars with Sigma(mu) = 1 per cent. We also explored the astrometric potential of the Catalogue of Objects and Measured Parameters from All Sky Surveys (COMPASS) data base in order to obtain additional proper motions for fainter stars in the area of Blanco 1. This effort produced the second catalogue of proper motions, CtlgD, containing 11 598 objects down to V similar to 21. A total of 4273 objects are common between the two catalogues. The accuracy of proper motions in CtlgD ranges from 1.0 to 6 mas yr-1. A combination of both proper-motion catalogues was instrumental in confirming that Blanco 1 contains a large population of M dwarfs (similar to 150 down to M5 V - the limit of our survey). In many respects, Blanco 1 is a scaled down 'twin' of the Pleiades. The noted discrepancy between the distance from a new Hipparcos parallax of Blanco 1 and the cluster's photometric distance, at least partially, might be due to the apparent correlation between parallax and proper motion in right ascension for the ensemble of cluster members.

THE ALLEN TELESCOPE ARRAY TWENTY-CENTIMETER SURVEY—A 700-SQUARE-DEGREE, MULTI-EPOCH RADIO DATA SET. II. INDIVIDUAL EPOCH TRANSIENT STATISTICS

We present our second paper on the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch, ∼700 deg2 radio image and catalog at 1.4 GHz. The survey is designed to detect rare, bright transients as well as to commission the ATA's wide-field survey capabilities. ATATS explores the challenges of multi-epoch transient and variable source surveys in the domain of dynamic range limits and changing (u, v) coverage. Here, we present images made using data from the individual epochs, as well as a revised image combining data from all ATATS epochs. The combined image has rms noise σ = 3.96 mJy beam−1, with a circular beam of 150'' FWHM. The catalog, generated using a false detection rate algorithm, contains 4984 sources and is >90% complete to 37.9 mJy. The catalogs generated from snapshot images of the individual epochs contain between 1170 and 2019 sources over the 564 deg2 area in common to all epochs. The 90% completeness limits of the single-epoch catalogs range from 98.6 to 232 mJy. We compare the catalog generated from the combined image to those from individual epochs, and from the NRAO VLA Sky Survey, a legacy survey at the same frequency. We are able to place new constraints on the transient population: fewer than 6 × 10−4 transients deg−2, for transients brighter than 350 mJy with characteristic timescales of minutes to days. This strongly rules out an astronomical origin for the ∼1 Jy sources reported by Matsumura et al. based on their stated rate of 3.1 × 10−3 deg−2.

AzTEC/ASTE 1.1 mm Deep Surveys: Number Counts and Clustering of Millimeter-bright Galaxies

We present results of a 1.1 mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25 deg2 area with an rms noise level of 0.32–0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We uncovered 198 sources with a significance of 3.5–15.6σ, providing the largest catalog of 1.1 mm sources in a contiguous region. Most of the sources are not detected in the far-infrared bands of the AKARI satellite, suggesting that they are mostly at z ≥ 1.5 given the detection limits. We construct differential and cumulative number counts of the ADF-S, the Subaru/XMM Newton Deep Field (SXDF), and the SSA 22 field surveyed by AzTEC/ASTE, which provide currently the tightest constraints on the faint end. The integration of the differential number counts of the ADF-S find that the contribution of 1.1 mm sources with ≥1 mJy to the cosmic infrared background (CIB) at 1.1 mm is 12–16%, suggesting that the large fraction of the CIB originates from faint sources of which number counts are not yet constrained. We estimate the cosmic star-formation rate density contributed by 1.1 mm sources with ≥1 mJy using the differential number counts and find that it is lower by about a factor of 5–10 compared to those derived from UV/optically-selected galaxies at z ~ 2–3. Clustering analyses of AzTEC sources in the ADF-S and the SXDF find that bright (>3 mJy) AzTEC sources are more strongly clustered than faint (< 3 mJy) AzTEC sources and the average mass of dark halos hosting bright AzTEC sources was calculated to be 1013–1014M⊙. Comparison of correlation length of AzTEC sources with other populations and with a bias evolution model suggests that dark halos hosting bright AzTEC sources evolve into systems of clusters at present universe and the AzTEC sources residing the dark halos evolve into massive elliptical galaxies located in the center of clusters.

The Relation Between Dust and Gas in the Taurus Molecular Cloud

We report a study of the relation between dust and gas over a 100 deg2 area in the Taurus molecular cloud. We compare the H2 column density derived from dust extinction with the CO column density derived from the 12CO and 13CO J = 1 → 0 lines. We derive the visual extinction from reddening determined from 2MASS data. The comparison is done at an angular size of 200′′, corresponding to 0.14 pc at a distance of 140 pc. We find that the relation between visual extinction AV and N(CO) is linear between AV ≃ 3 and 10 mag in the region associated with the B213–L1495 filament. In other regions the linear relation flattens for AV ≳ 4 mag. Accounting for the observed relation between the column density of CO and CO2 ices and AV, we find a linear relationship between the column of carbon monoxide and dust for observed visual extinctions up to the maximum value in our data ≃23 mag.

OPTICAL IMAGES AND SOURCE CATALOG OF AKARI NORTH ECLIPTIC POLE WIDE SURVEY FIELD

We present the source catalog and the properties of the B-, R-, and I-band images obtained to support the AKARI North Ecliptic Pole Wide (NEP-Wide) survey. The NEP-Wide is an AKARI infrared imaging survey of the north ecliptic pole covering a 5.8 deg2 area over 2.5–6 μm wavelengths. The optical imaging data were obtained at the Maidanak Observatory in Uzbekistan using the Seoul National University 4k × 4k Camera on the 1.5 m telescope. These images cover 4.9 deg2 where no deep optical imaging data are available. Our B-, R-, and I-band data reach the depths of ∼23.4, ∼23.1, and ∼22.3 mag (AB) at 5σ, respectively. The source catalog contains 96,460 objects in the R band, and the astrometric accuracy is about 015 at 1σ in each R.A. and decl. direction. These photometric data will be useful for many studies including identification of optical counterparts of the infrared sources detected by AKARI, analysis of their spectral energy distributions from optical through infrared, and the selection of interesting objects to understand the obscured galaxy evolution.

1318 new variable stars in a 0.25 square degree region of the Galactic plane

We have conducted a deep photometric survey of a 0.5 deg x 0.5 deg area of the Galactic Plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day observation run in 2005, supplemented by 63 images from a six week period in 2002. Our reduction employed the new numerical kernel difference image analysis method as implemented in the PYSIS3 code and resulted in more than 500,000 lightcurves of stars down to a magnitude limit of R ~ 24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.

NEAR-IR SPECTROSCOPY OF YOUNG STARS IN THE BRAID NEBULA STAR FORMATION REGION IN CYGNUS OB7

We present 1.4–2.5 μm integral field spectroscopy of 16 stars in the Braid Nebula star formation region in Cygnus OB7. These data form one aspect of a large-scale multiwavelength survey aimed at determining an unbiased estimate of the number, mass distribution, and evolutionary state of the young stars within this 1 deg2 area of the previously poorly studied Lynds 1003 molecular cloud. Our new spectroscopic data, when combined with Two Micron All Sky Survey near-IR photometry, provide evidence of membership of many of these objects in the regions' pre-main-sequence population. We discuss both the characteristics of the young stars found in the region and the level of starforming activity present.