16,627 research outputs found
HFF-DeepSpace photometric catalogs of the 12 Hubble frontier fields, clusters, and parallels : photometry, photometric redshifts, and stellar masses
We present Hubble multi-wavelength photometric catalogs, including (up to) 17 filters with the Advanced Camera for Surveys and Wide Field Camera 3 from the ultra-violet to near-infrared for the Hubble Frontier Fields and associated parallels. We have constructed homogeneous photometric catalogs for all six clusters and their parallels. To further expand these data catalogs, we have added ultra-deep KS-band imaging at 2.2. mu m from the Very Large Telescope HAWK-I and Keck-I MOSFIRE instruments. We also add post-cryogenic Spitzer imaging at 3.6 and 4.5. mu m with the Infrared Array Camera (IRAC), as well as archival IRAC 5.8 and 8.0. mu m imaging when available. We introduce the public release of the multi-wavelength (0.2-8 mu m) photometric catalogs, and we describe the unique steps applied for the construction of these catalogs. Particular emphasis is given to the source detection band, the contamination of light from the bright cluster galaxies (bCGs), and intra-cluster light (ICL). In addition to the photometric catalogs, we provide catalogs of photometric redshifts and stellar population properties. Furthermore, this includes all the images used in the construction of the catalogs, including the combined models of bCGs and ICL, the residual images, segmentation maps, and more. These catalogs are a robust data set of the Hubble Frontier Fields and will be an important aid in designing future surveys, as well as planning follow-up programs with current and future observatories to answer key questions remaining about first light, reionization, the assembly of galaxies, and many more topics, most notably by identifying high-redshift sources to target
Deep-sea image processing
High-resolution seafloor mapping often requires optical methods of sensing, to confirm interpretations made from sonar data. Optical digital imagery of seafloor sites can now provide very high resolution and also provides additional cues, such as color information for sediments, biota and divers rock types. During the cruise AT11-7 of the Woods Hole Oceanographic Institution (WHOI) vessel R/V Atlantis (February 2004, East Pacific Rise) visual imagery was acquired from three sources: (1) a digital still down-looking camera mounted on the submersible Alvin, (2) observer-operated 1-and 3-chip video cameras with tilt and pan capabilities mounted on the front of Alvin, and (3) a digital still camera on the WHOI TowCam (Fornari, 2003). Imagery from the first source collected on a previous cruise (AT7-13) to the Galapagos Rift at 86°W was successfully processed and mosaicked post-cruise, resulting in a single image covering area of about 2000 sq.m, with the resolution of 3 mm per pixel (Rzhanov et al., 2003). This paper addresses the issues of the optimal acquisition of visual imagery in deep-seaconditions, and requirements for on-board processing. Shipboard processing of digital imagery allows for reviewing collected imagery immediately after the dive, evaluating its importance and optimizing acquisition parameters, and augmenting acquisition of data over specific sites on subsequent dives.Images from the deepsea power and light (DSPL) digital camera offer the best resolution (3.3 Mega pixels) and are taken at an interval of 10 seconds (determined by the strobe\u27s recharge rate). This makes images suitable for mosaicking only when Alvin moves slowly (≪1/4 kt), which is not always possible for time-critical missions. Video cameras provided a source of imagery more suitable for mosaicking, despite its inferiority in resolution. We discuss required pre-processing and imageenhancement techniques and their influence on the interpretation of mosaic content. An algorithm for determination of camera tilt parameters from acquired imagery is proposed and robustness conditions are discussed
Ultra-deep Large Binocular Camera U-band Imaging of the GOODS-North Field: Depth vs. Resolution
We present a study of the trade-off between depth and resolution using a
large number of U-band imaging observations in the GOODS-North field
(Giavalisco et al. 2004) from the Large Binocular Camera (LBC) on the Large
Binocular Telescope (LBT). Having acquired over 30 hours of data (315 images
with 5-6 mins exposures), we generated multiple image mosaics, starting with
the best atmospheric seeing images (FWHM 0.8"), which constitute
10% of the total data set. For subsequent mosaics, we added in data with
larger seeing values until the final, deepest mosaic included all images with
FWHM 1.8" (94% of the total data set). From the mosaics, we
made object catalogs to compare the optimal-resolution, yet shallower image to
the lower-resolution but deeper image. We show that the number counts for both
images are 90% complete to . Fainter than
27, the object counts from the optimal-resolution image start to
drop-off dramatically (90% between = 27 and 28 mag), while the deepest
image with better surface-brightness sensitivity ( 32
mag arcsec) show a more gradual drop (10% between 27
and 28 mag). For the brightest galaxies within the GOODS-N field, structure and
clumpy features within the galaxies are more prominent in the
optimal-resolution image compared to the deeper mosaics. Finally, we find - for
220 brighter galaxies with 24 mag - only marginal
differences in total flux between the optimal-resolution and lower-resolution
light-profiles to 32 mag arcsec. In only 10% of
the cases are the total-flux differences larger than 0.5 mag. This helps
constrain how much flux can be missed from galaxy outskirts, which is important
for studies of the Extragalactic Background Light.Comment: 24 pages, 14 figures, submitted to PASP, comments welcom
The ATESP Radio Survey II. The Source Catalogue
This paper is part of a series reporting the results of the Australia
Telescope ESO Slice Project (ATESP) radio survey obtained at 1400 MHz with the
Australia Telescope Compact Array (ATCA) over the region covered by the ESO
Slice Project (ESP) galaxy redshift survey. The survey consists of 16 radio
mosaics with ~8"x14" resolution and uniform sensitivity (1sigma noise level ~79
microJy) over the whole area of the ESP redshift survey (~26 sq. degrees at
decl. -40 degr). Here we present the catalogue derived from the ATESP survey.
We detected 2960 distinct radio sources down to a flux density limit of ~0.5
mJy (6sigma), 1402 being sub-mJy sources. We describe in detail the procedure
followed for the source extraction and parameterization. The internal accuracy
of the source parameters was tested with Monte Carlo simulations and possible
systematic effects (e.g. bandwidth smearing) have been quantified.Comment: 14 pages, 14 Postscript figures, Accepted for publication in A&A
Suppl. Corrected typos and added Journal Referenc
WINGS: a WIde-field nearby Galaxy-cluster survey III. Deep near-infrared photometry of 28 nearby clusters
Context. This is the third paper of a series devoted to the WIde-field Nearby
Galaxy-cluster Survey (WINGS).WINGS is a long term project aimed at gathering
wide-field, multiband imaging and spectroscopy of galaxies in a complete sample
of 77 X-ray selected nearby clusters (0.04<z<0.07) located far from the
galactic plane (b>20deg). The main goal of this project is to establish a local
reference sample for evolutionary studies of galaxies and galaxy clusters.
Aims. This paper presents the near-infrared (J,K) photometric catalogs of 28
clusters of the WINGS sample and describes the procedures followed to construct
them. Methods. The raw data has been reduced at CASU and special care has been
devoted to the final coadding, drizzling technique, astrometric solution and
magnitude calibration for the WFCAM pipeline processed data. We have
constructed the photometric catalogs based on the final calibrated coadded
mosaics (0.79 deg2) in J (19 clusters) and K (27 clusters) bands. A customized
interactive pipeline has been used to clean the catalogs and to make mock
images for photometric errors and completeness estimates. Results. We provide
deep near-infrared photometric catalogs (90% complete in detection rate at
total magnitudes J =20.5, K =19.4, and in classification rate at J = 19.5 and K
= 18.5), giving positions, geometrical parameters, total and aperture
magnitudes for all detected sources. For each field we classify the detected
sources as stars, galaxies and objects of "unknown" nature.Comment: Published by A&A501.851 - 15 pages, 3 tables, 13 figures. Catalogs
will be available via CDS and http://web.oapd.inaf.it/wing
Automated pebble mosaic stylization of images
Digital mosaics have usually used regular tiles, simulating the historical
"tessellated" mosaics. In this paper, we present a method for synthesizing
pebble mosaics, a historical mosaic style in which the tiles are rounded
pebbles. We address both the tiling problem, where pebbles are distributed over
the image plane so as to approximate the input image content, and the problem
of geometry, creating a smooth rounded shape for each pebble. We adapt SLIC,
simple linear iterative clustering, to obtain elongated tiles conforming to
image content, and smooth the resulting irregular shapes into shapes resembling
pebble cross-sections. Then, we create an interior and exterior contour for
each pebble and solve a Laplace equation over the region between them to obtain
height-field geometry. The resulting pebble set approximates the input image
while presenting full geometry that can be rendered and textured for a highly
detailed representation of a pebble mosaic
CfAIR2: Near Infrared Light Curves of 94 Type Ia Supernovae
CfAIR2 is a large homogeneously reduced set of near-infrared (NIR) light
curves for Type Ia supernovae (SN Ia) obtained with the 1.3m Peters Automated
InfraRed Imaging TELescope (PAIRITEL). This data set includes 4607 measurements
of 94 SN Ia and 4 additional SN Iax observed from 2005-2011 at the Fred
Lawrence Whipple Observatory on Mount Hopkins, Arizona. CfAIR2 includes JHKs
photometric measurements for 88 normal and 6 spectroscopically peculiar SN Ia
in the nearby universe, with a median redshift of z~0.021 for the normal SN Ia.
CfAIR2 data span the range from -13 days to +127 days from B-band maximum. More
than half of the light curves begin before the time of maximum and the coverage
typically contains ~13-18 epochs of observation, depending on the filter. We
present extensive tests that verify the fidelity of the CfAIR2 data pipeline,
including comparison to the excellent data of the Carnegie Supernova Project.
CfAIR2 contributes to a firm local anchor for supernova cosmology studies in
the NIR. Because SN Ia are more nearly standard candles in the NIR and are less
vulnerable to the vexing problems of extinction by dust, CfAIR2 will help the
supernova cosmology community develop more precise and accurate extragalactic
distance probes to improve our knowledge of cosmological parameters, including
dark energy and its potential time variation.Comment: 31 pages, 15 figures, 10 tables. Accepted to ApJS. v2 modified to
more closely match journal versio
Galaxy Formation In The Reionization Epoch As Hinted By Wide Field Camera 3 Observations Of The Hubble Ultra Deep Field
We present a large sample of candidate galaxies at z~7--10, selected in the
HUDF using the new observations made by the HST/WFC3. Our sample is composed of
20 z-dropouts, 15 Y-dropouts, and 20 J-dropouts. The surface densities of the
z-dropouts are close to what predicted by earlier studies, however, those of
the Y- and J-dropouts are quite unexpected. While no Y- or J-dropouts have been
found at AB < 28.0 mag, their surface densities seem to increase sharply at
fainter levels. While some of these candidates seem to be close to foreground
galaxies and thus could possibly be gravitationally lensed, the overall surface
densities after excluding such cases are still much higher than what would be
expected if the luminosity function does not evolve from z~7 to 10. Motivated
by such steep increases, we tentatively propose a set of Schechter function
parameters to describe the LFs at z~8 and 10. As compared to their counterpart
at z~7, here L* decreases by ~ 6.5x and Phi* increases by 17--90x. Although
such parameters are not yet demanded by the existing observations, they are
allowed and seem to agree with the data better than other alternatives. If
these LFs are still valid beyond our current detection limit, this would imply
a sudden emergence of a large number of low-luminosity galaxies when looking
back in time to z~10, which, while seemingly exotic, would naturally fit in the
picture of the cosmic hydrogen reionization. These early galaxies could easily
account for the ionizing photon budget required by the reionization, and they
would imply that the global star formation rate density might start from a very
high value at z~10, rapidly reach the minimum at z~7, and start to rise again
towards z~6. In this scenario, the majority of the stellar mass that the
universe assembled through the reionization epoch seems still undetected by
current observations at z~6. [Abridged]Comment: accepted for publication in Research in Astronomy and Astrophysic
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