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
images.
These spectra are optical follow-up observations of the
X-ray sources detected in the 942 ks exposure of the
Chandra Deep Field-South (CDFS) using FORS.
The Panchromatic High-Resolution Spectroscopic Survey of Local Group
Star Clusters PCSLG
Short Name:
PCSLG SSAP
Date:
23 Mar 2022 13:13:17
Publisher:
The GAVO DC team
Description:
This dataset contains spectroscopic observations of 29 globular
clusters in the Magellanic Clouds and the Milky Way performed with
VLT/X-shooter over eight full nights.
The zCOSMOS redshift survey used 600h on the VIMOS spectrograph spread over
five observing seasons (2005-2009) to obtain spectra of about 20,000 galaxies
selected to have Iab < 22.5 across the full 1.7 deg2 of the COSMOS field.
This part, "zCOSMOS-bright", was designed to yield a high and fairly uniform
sampling rate (about 70%), with a high success rate in measuring redshifts
(approaching 100% at 0.5 < z < 0.8), and with sufficient
velocity accuracy
(about 100 km/s) to efficiently map the environments of galaxies down to the
scale of galaxy groups out to redshifts z ~ 1.