scholarly journals SuperCLASS – I. The super cluster assisted shear survey: Project overview and data release 1

2020 ◽  
Vol 495 (2) ◽  
pp. 1706-1723 ◽  
Author(s):  
Richard A Battye ◽  
Michael L Brown ◽  
Caitlin M Casey ◽  
Ian Harrison ◽  
Neal J Jackson ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Near Infrared ◽  
Correlation Technique ◽  
Large Array ◽  
Photometric Redshifts ◽  
Very Large Array ◽  
Infrared Observations ◽  
Data Release ◽  
L Band ◽  
Cross Correlation Technique

ABSTRACT The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4 GHz) to a r.m.s. of $7\, \mu {\rm Jy}\,$beam−1 over an area of $\sim 1\, {\rm deg}^2$ centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements with the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity out to z ∼ 1. In this paper we give an overview of the project including the science goals and multiwavelength coverage before presenting the first data release. We have analysed around 400 h of e-MERLIN data allowing us to create a Data Release 1 (DR1) mosaic of $\sim 0.26\, {\rm deg}^2$ to the full depth. These observations have been supplemented with complementary radio observations from the Karl G. Jansky Very Large Array (VLA) and optical/near infrared observations taken with the Subaru, Canada-France-Hawaii, and Spitzer Telescopes. The main data product is a catalogue of 887 sources detected by the VLA, of which 395 are detected by e-MERLIN and 197 of these are resolved. We have investigated the size, flux, and spectral index properties of these sources finding them compatible with previous studies. Preliminary photometric redshifts, and an assessment of galaxy shapes measured in the radio data, combined with a radio-optical cross-correlation technique probing cosmic shear in a supercluster environment, are presented in companion papers.

scholarly journals The emergence of the red sequence at z~2 seen through galaxy clustering in the UKIDSS UDS

2012 ◽  
Vol 8 (S295) ◽  
pp. 105-108
Author(s):  
William G. Hartley ◽  
Omar Almaini ◽  
Alice Mortlock ◽  
Chris Conselice ◽  
Keyword(s):  
Dark Matter ◽  
Cross Correlation ◽  
Near Infrared ◽  
Correlation Technique ◽  
Dark Matter Halos ◽  
Star Forming ◽  
Deep Survey ◽  
Cross Correlation Technique ◽  
Infrared Survey

AbstractWe use the UKIDSS Ultra-Deep Survey, the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and passive galaxies to z ~ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter halos with Mhalo > 1013 M⊙ irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies.

scholarly journals Comparing C- and L-band SAR images for sea ice motion estimation

2015 ◽  
Vol 9 (1) ◽  
pp. 357-366 ◽  
Author(s):  
J. Lehtiranta ◽  
S. Siiriä ◽  
J. Karvonen
Keyword(s):  
Motion Estimation ◽  
Sea Ice ◽  
Cross Correlation ◽  
Correlation Technique ◽  
Sar Images ◽  
L Band ◽  
The Baltic ◽  
Cross Correlation Technique ◽  
Multiyear Ice ◽  
Band Image

Abstract. Pairs of consecutive C-band synthetic-aperture radar (SAR) images are routinely used for sea ice motion estimation. The L-band radar has a fundamentally different character, as its longer wavelength penetrates deeper into sea ice. L-band SAR provides information on the seasonal sea ice inner structure in addition to the surface roughness that dominates C-band images. This is especially useful in the Baltic Sea, which lacks multiyear ice and icebergs, known to be confusing targets for L-band sea ice classification. In this work, L-band SAR images are investigated for sea ice motion estimation using the well-established maximal cross-correlation (MCC) approach. This work provides the first comparison of L-band and C-band SAR images for the purpose of motion estimation. The cross-correlation calculations are hardware accelerated using new OpenCL-based source code, which is made available through the author's web site. It is found that L-band images are preferable for motion estimation over C-band images. It is also shown that motion estimation is possible between a C-band and an L-band image using the maximal cross-correlation technique.

scholarly journals Characterization and verification of ACAM slit functions for trace-gas retrievals during the 2011 DISCOVER-AQ flight campaign

2015 ◽  
Vol 8 (2) ◽  
pp. 751-759 ◽  
Author(s):  
C. Liu ◽  
X. Liu ◽  
M. G. Kowalewski ◽  
S. J. Janz ◽  
G. González Abad ◽  
...  
Keyword(s):  
Air Quality ◽  
Cross Correlation ◽  
Near Infrared ◽  
Gas Absorption ◽  
Trace Gas ◽  
Correlation Technique ◽  
Reference Spectrum ◽  
Infrared Spectrometer ◽  
Cross Correlation Technique ◽  
Near Infrared Spectrometer

Abstract. The Airborne Compact Atmospheric Mapper (ACAM), an ultraviolet/visible/near-infrared spectrometer, has been flown on board the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaigns to provide remote sensing observations of tropospheric and boundary-layer pollutants from its radiance measurements. To assure the trace-gas retrieval from ACAM measurements we perform detailed characterization and verification of ACAM slit functions. The wavelengths and slit functions of ACAM measurements are characterized for the air-quality channel (~304–500 nm) through cross-correlation with a high-resolution solar irradiance reference spectrum after necessarily accounting for atmospheric gas absorption and the ring effect in the calibration process. The derived slit functions, assuming a hybrid combination of asymmetric Gaussian and top-hat slit functions, agree very well with the laboratory-measured slit functions. Comparisons of trace-gas retrievals between using derived and measured slit functions demonstrate that the cross-correlation technique can be reliably used to characterize slit functions for trace-gas retrievals.

scholarly journals Characterization and verification of ACAM slit functions for trace gas retrievals during the 2011 DISCOVER-AQ flight campaign

2014 ◽  
Vol 7 (11) ◽  
pp. 11415-11437
Author(s):  
C. Liu ◽  
X. Liu ◽  
M. G. Kowalewski ◽  
S. J. Janz ◽  
G. González Abad ◽  
...  
Keyword(s):  
Air Quality ◽  
Cross Correlation ◽  
Near Infrared ◽  
Gas Absorption ◽  
Trace Gas ◽  
Correlation Technique ◽  
Reference Spectrum ◽  
Infrared Spectrometer ◽  
Cross Correlation Technique ◽  
Near Infrared Spectrometer

Abstract. The Airborne Compact Atmospheric Mapper (ACAM), an ultraviolet/visible/near-infrared spectrometer, has been flown on board the NASA UC-12 aircraft during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) campaigns to provide remote sensing observations of tropospheric and boundary layer pollutants from its radiance measurements. To improve the trace gas retrieval from ACAM measurements, we perform detailed characterization and verification of ACAM slit functions. The wavelengths and slit functions of ACAM measurements are characterized for the air quality channel (~304–500 nm) through cross-correlation with a high-resolution solar irradiance reference spectrum after necessarily accounting for atmospheric gas absorption and the Ring effect in the calibration process. The derived slit functions, assuming a hybrid combination of asymmetric Gaussian and top-hat slit functions, agree very well with the laboratory-measured slit functions. Comparisons of trace gas retrievals between using derived and measured slit functions demonstrate that the cross-correlation technique can be reliably used to characterize slit functions for trace gas retrievals.

scholarly journals Comparing C- and L-band SAR images for sea ice motion estimation

2014 ◽  
Vol 8 (3) ◽  
pp. 2721-2757
Author(s):  
J. Lehtiranta ◽  
S. Siiriä ◽  
J. Karvonen
Keyword(s):  
Motion Estimation ◽  
Sea Ice ◽  
Cross Correlation ◽  
Correlation Technique ◽  
Sar Images ◽  
L Band ◽  
Sar Imagery ◽  
The Baltic ◽  
Cross Correlation Technique ◽  
Multiyear Ice

Abstract. Pairs of consecutive C-band SAR images are routinely used for sea ice motion estimation. In addition to the surface roughness L-band SAR imagery provides information of the seasonal sea ice inner structure, which is especially useful in the Baltic Sea lacking multiyear ice and icebergs. In this work, L-band SAR images are investigated for sea ice motion estimation using the well-established maximal cross-correlation approach. This work provides the first comparison of L-band and C-band SAR images for the purpose of motion estimation. The cross-correlation calculations are hardware accelerated using new OpenCL-based source code, which is made available through the author's web site. It is found that L-band images are preferable for motion estimation over C-band images. It is also shown that motion estimation is possible between a C-band and an L-band image using the maximal cross-correlation technique.

scholarly journals Visible and near-infrared digital images for determination of ice velocities and surface elevation during a surge on Osbornebreen, a tidewater glacier in Svalbard

1997 ◽  
Vol 24 ◽  
pp. 255-261 ◽  
Author(s):  
Cecilie Rolstad ◽  
Jostein Amlien ◽  
Jon-Ove Hagen ◽  
Bengt Lundén
Keyword(s):  
Velocity Field ◽  
Near Infrared ◽  
Aerial Photographs ◽  
Correlation Technique ◽  
Digital Elevation ◽  
Compressive Flow ◽  
Tidewater Glacier ◽  
Extension Zone ◽  
Elevation Model ◽  
Cross Correlation Technique

A field of vectors showing the average velocity of the surging glacier Osbornebreen, Svalbard, was determined by comparing sequential SPOT (Système pour l’Observation de la Terre) and Landsat thematic mapper images. Crevasses which developed during the initial phase of the surge in the winter of 1986–87 were tracked using a fast Fourier chip cross-correlation technique. A digital elevation model (DEM) was developed using digital photogrammetry on aerial photographs from 1990. This new DEM was compared with a map drawn in 1966. The velocity field could be almost entirely determined with 1 month separation of the images, but only partly determined with images 1 year apart, due to changes of the crevasse pattern. The velocity field is similar to that found for Kronebreen, a continuously fast-moving tidewater glacier. No distinct zones of compressive flow were present and the data gave no evidence of a compression zone/surge front traveling downstream. The velocity field, the rapid advance of the terminus and the development of transverse crevasses in the upper accumulation area within a 6 month period may indicate that the surge developed as a zone of extension starting near the terminus and propagating quickly upstream. The crevasse pattern in the images is therefore interpreted to be the result of the extension zone traveling upstream, and, as the whole glacier starts to slide, the crevasse pattern alters according to the bedrock topography.

Raman Chemical Imaging of Explosive-Contaminated Fingerprints

2009 ◽  
Vol 63 (11) ◽  
pp. 1197-1203 ◽  
Author(s):  
E. D. Emmons ◽  
A. Tripathi ◽  
J. A. Guicheteau ◽  
S. D. Christesen ◽  
A. W. Fountain
Keyword(s):  
Cross Correlation ◽  
Chemical Imaging ◽  
Correlation Technique ◽  
Bright Field ◽  
Characteristic Region ◽  
Biometric Analysis ◽  
Imaging Results ◽  
Raman Chemical Imaging ◽  
Cross Correlation Technique ◽  
Field Imaging

Raman chemical imaging (RCI) has been used to detect and identify explosives in contaminated fingerprints. Bright-field imaging is used to identify regions of interest within a fingerprint, which can then be examined to determine their chemical composition using RCI and fluorescence imaging. Results are presented where explosives in contaminated fingerprints are identified and their spatial distributions are obtained. Identification of explosives is obtained using Pearson's cosine cross-correlation technique using the characteristic region (500–1850 cm−1) of the spectrum. This study shows the ability to identify explosives nondestructively so that the fingerprint remains intact for further biometric analysis. Prospects for forensic examination of contaminated fingerprints are discussed.

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