In this data release from the ongoing LOw-Frequency ARray (LOFAR)
Two-metre Sky Survey (LoTSS) we present 120-168 MHz images covering
27% of the northern sky. Our coverage is split into two regions
centred at approximately 12h45m +44°30′ and 1h00m +28°00′ and spanning
4178 and 1457 square degrees respectively. The images were derived
from 3,451 hrs (7.6 PB) of LOFAR High Band Antenna data which were
corrected for the direction-independent instrumental properties as
well as direction-dependent ionospheric distortions during extensive,
but fully automated, data processing. A catalogue of 4,395,448 radio
sources is derived from our total intensity (Stokes I) maps, where the
majority of these have never been detected at radio wavelengths
before. At 6′′ resolution, our full bandwidth Stokes I continuum maps
with a central frequency of 144 MHz have: a median rms sensitivity of
83 μ Jy/beam; a flux density scale accuracy of approximately 10%; an
astrometric accuracy of 0.2′′; and we estimate the point-source
completeness to be 90% at a peak brightness of 0.8 mJy/beam. By
creating three 16 MHz bandwidth images across the band we are able to
measure the in-band spectral index of many sources, albeit the error
on the derived spectral index is > ±0.2 which is a consequence of our
flux-density scale accuracy and small fractional bandwidth. Our
circular polarisation (Stokes V) 20′′ resolution 120-168 MHz continuum
images have a median rms sensitivity of 95 μ Jy/beam, and we estimate
a Stokes I to Stokes V leakage of 0.056%. Our linear polarisation
(Stokes Q and Stokes U) image cubes consist of 480 97.6 kHz wide
planes and have a median rms sensitivity per plane of 10.8mJy/beam at
4′ and 2.2mJy/beam at 20′′; we estimate the Stokes I to Stokes Q/U
leakage to be approximately 0.2%. Here we characterise and publicly
release our Stokes I, Q, U and V images in addition to the calibrated
uv-data to facilitate the thorough scientific exploitation of this
unique dataset. This service queries the Stokes I continuum mosaic
source catalogue.
This service queries the catalog of images from the LOFAR HBA Tier-1
preliminary data release (LoTSS-PDR). This data release contains
images and catalogs that characterise the low-frequency radio emission
in the region of the HETDEX Spring Field. In excess of 40,000 sources
are detected in the images that cover an area of over 350 square
degrees, have a resolution of 25 arcsec, and typical noise levels of
less than 0.5 mJy/beam.
This service provides cutouts from the images of the LOFAR HBA Tier-1
preliminary data release (LoTSS-PDR). This data release contains
images and catalogs that characterise the low-frequency radio emission
in the region of the HETDEX Spring Field. In excess of 40,000 sources
are detected in the images that cover an area of over 350 square
degrees, have a resolution of 25 arcsec, and typical noise levels of
less than 0.5 mJy/beam.
A catalogue of E(V-I) extinction values is presented for 3174 (LMC)
and 693 (SMC) fields within the Magellanic Clouds. The extinction
values were computed by determining the (V-I) colour difference of the
red clump from Optical Gravitational Microlensing Experiment (OGLE
III) observations in the V and I bands and theoretical values for
unreddend red clump colours.
The MAGIC project observes the VHE sky (GeV~TeV) through Cherenkov
radiation events. The project is operating since 2004 and with the
support from the Spain-VO team they provide data access through a
VO-SSAP and web services. This service re-publishes the data with
homogeneized in flux units (given here in 'erg/(s.cm2)'). Photon
energy values in are transfomred to frequencies.
The MAGIC project observes the VHE sky (GeV~TeV) through Cherenkov
radiation events. The project is operating since 2004 and with the
support from the Spain-VO team they provide data access through a
VO-SSAP and web services. Our goal here is to provide the same kind of
service with the difference that the data is transformed and
homogeneized in its flux units, to values in 'erg/(s.cm2)', and photon
energy values in equivalent 'Hz' frequency values.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The 2MASS Photometric Redshift catalogue (2MPZ) is constructed by cross-matching 2MASS XSC, WISE and SuperCOSMOS all-sky samples and employing the artificial neural network approach (the ANNz algorithm, Collister & Lahav 2004), trained on several redshift surveys (2MRS, SDSS, 6dFGS, 2dFGRS and ZCAT). The derived photometric redshifts have errors nearly independent of distance, with an all-sky accuracy of Ïz = 0.015, and a very small percentage of outliers. These redshift estimates have a typical precision of 12% for all the 2MASS XSC galaxies that lack spectroscopy. The resulting 2MPZ sample contains almost 1 million galaxies with a median redshift of z=0.07. This catalogue is described in Bilicki et al. 2014, ApJS, 210, 9.
The 2MASS Point Source Catalogue, short a couple of exotic fields. We
provide this data mainly for matching with other catalogs within our
TAP service.
MAST SkyMapper Southern Survey Data Release 4 (SMSS DR4)
Short Name:
MAST SkyMapper
Date:
16 Apr 2024 20:18:39
Publisher:
Space Telescope Science Institute Archive
Description:
MAST hosts a copy of the SkyMapper DR4 catalog.
SMSS DR4 contains optical photometry in the 6 SkyMapper filters (u,v,g,r,i,z) for ~700 million astrophysical sources over 26,000 sq.deg, ranging from the South Celestial Pole to Dec=+16 degrees for objects with data in all bands, and some sources as far North as +29 degrees. The photometry is drawn from over 15 billion measurements made from more than 400,000 images acquired by the 1.3m SkyMapper telescope between March 2014 and September 2021. The typical 10-sigma depths for each field range between 18.5 and 20.5 ABmag, depending on the filter, but certain sky regions include longer exposures that reach as deep as 22 ABmag.
Compared to previous SkyMapper data releases, DR4 includes significant enhancements in data processing, most notably a new photometric calibration anchored to synthetic photometry from Gaia low-resolution spectroscopy, which resolves reddening- and spatial-trends identified in previous releases, especially in the bluest filters, u and v.
A large number of other photometric and spectroscopic surveys have been cross-matched to the dr4.master table of objects, to facilitate various scientific investigations.
