1,948 research outputs found
Faint InfraRed Extragalactic Survey: Data and Source Catalogue of the MS1054-03 field
We present deep near-infrared Js, H, and Ks band imaging of a field around
MS1054-03, a massive cluster at z=0.83. The observations were carried out with
ISAAC at the ESO VLT as part of the Faint InfraRed Extragalactic Survey
(FIRES). The total integration time amounts to 25.9h in Js, 24.4h in H, and
26.5h in Ks, divided nearly equally between four pointings covering 5.5'x5.3'.
The 3-sigma total limiting AB magnitudes for point sources from the shallowest
to deepest pointing are Js=26.0-26.2, H=25.5-25.8, and Ks=25.3-25.7. The
effective spatial resolution of the coadded images has FWHM=0.48", 0.46", and
0.52" in Js, H, and Ks. We complemented the ISAAC data with deep optical
imaging using existing HST WFPC2 mosaics in the F606W and F814W filters and new
U, B and V band data from VLT FORS1. We constructed a Ks-band limited
multicolour source catalogue to Ks(total,AB)=25 (about 5-sigma for point
sources). The catalogue contains 1858 objects, of which 1663 have eight-band
photometry. We describe the observations, data reduction, source detection and
photometric measurements method. We present the number counts, colour
distributions, and photometric redshifts z_ph of the catalogue sources. We find
that our counts at the faint end 22<Ks(AB)<25, with slope dlog(N)/dm=0.20, lie
at the flatter end of published counts in other deep fields and are consistent
with those we derived in the HDF-South, the other FIRES field. Spectroscopic
redshifts z_sp are available for about 330 sources in the MS1054-03 field;
comparison between the z_ph and z_sp shows very good agreement, with
=0.078. The MS1054-03 field observations complement our
HDF-South data set with nearly five times larger area at about 0.7 brighter
magnitudes. [ABRIDGED]Comment: Accepted for publication in the Astronomical Journal. 32 pages, 14
b/w figures, 1 color figur
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 (âȘ1/4 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
Meteorological interpretation of Nimbus High Resolution Infrared /HRIR/ data
Nimbus satellite high resolution infrared photographic data analysi
FIGS -- Faint Infrared Grism Survey: Description and Data Reduction
The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST)
WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four
deep fields. Two fields are located in the Great Observatories Origins Deep
Survey-North (GOODS-N) area and two fields are located in the Great
Observatories Origins Deep Survey-South (GOODS-S) area. One of the southern
fields selected is the Hubble Ultra Deep Field. Each of these four fields were
observed using the WFC3/G102 grism (0.8-1.15 continuous coverage)
with a total exposure time of 40 orbits (~ 100 kilo-seconds) per field. This
reaches a 3 sigma continuum depth of ~26 AB magnitudes and probes emission
lines to . This paper details the four
FIGS fields and the overall observational strategy of the project. A detailed
description of the Simulation Based Extraction (SBE) method used to extract and
combine over 10000 spectra of over 2000 distinct sources brighter than
m_F105W=26.5 mag is provided. High fidelity simulations of the observations is
shown to significantly improve the background subtraction process, the spectral
contamination estimates, and the final flux calibration. This allows for the
combination of multiple spectra to produce a final high quality, deep,
1D-spectra for each object in the survey.Comment: 21 Pages. 17 Figures. To appear in Ap
The Role of Provenance Management in Accelerating the Rate of Astronomical Research
The availability of vast quantities of data through electronic archives has
transformed astronomical research. It has also enabled the creation of new
products, models and simulations, often from distributed input data and models,
that are themselves made electronically available. These products will only
provide maximal long-term value to astronomers when accompanied by records of
their provenance; that is, records of the data and processes used in the
creation of such products. We use the creation of image mosaics with the
Montage grid-enabled mosaic engine to emphasize the necessity of provenance
management and to understand the science requirements that higher-level
products impose on provenance management technologies. We describe experiments
with one technology, the "Provenance Aware Service Oriented Architecture"
(PASOA), that stores provenance information at each step in the computation of
a mosaic. The results inform the technical specifications of provenance
management systems, including the need for extensible systems built on common
standards. Finally, we describe examples of provenance management technology
emerging from the fields of geophysics and oceanography that have applicability
to astronomy applications.Comment: 8 pages, 1 figure; Proceedings of Science, 201
Status of availability of Mariner 9 (1971-051A) TV picture data
The Mariner 9 TV data that are now available from the National Space Science Data Center are described. Included are the mission test video system pictures, image processing laboratory/reduced data records, mosaics, and journal articles
Sensor-Assisted Video Mosaicing for Seafloor Mapping
This paper discusses a proposed processing technique for combining video imagery with auxiliary sensor information. The latter greatly simplifies image processing by reducing complexity of the transformation model. The mosaics produced by this technique are adequate for many applications, in particular habitat mapping. The algorithm is demonstrated through simulations and hardware configuration is described
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