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.
This service provides access to and information about the 2MASS All-Sky Atlas Images. Atlas Images delivered by this service are in FITS format and contain full WCS information in their headers. Additionally, the image headers contain photometric zero point information. 2MASS Atlas Images are suitable for quantitative photometric measurements.
This service provides access to and information about the 2MASS All-Sky Quicklook Images. The Quicklook Images delivered by this service are restored from lossy-compressed files in FITS format with full WCS information contained in the image headers. These images are suitable for position measurements, finding charts and visual inspection of the near-infrared sky.
The high sensitivity and angular resolution of the 2MASS Large Galaxy Atlas (LGA) images allows closer inspection of diverse stellar populations, large-scale structures such as spirals, bulges, warps and bars, star formation regions and evolution of galaxies. This image atlas represents the first uniform, all-sky, view of galaxies as seen in the near-infrared wavelength window that is most sensitive to the dominant mass component of galaxies.
Herschel data from the "Mass-loss of Evolved StarS" (MESS) Guaranteed-Time Key Program are available here. IRSA is serving the MESS PACS imaging of 108 evolved stars. This is Herschel program KPGT_mgroen01_1.
The sample of AGB stars has been selected to cover all chemical types (M-, S-, C-stars), variability types (irregular, semi-regular, Miras) and periods, and mass-loss rates. Stars have been selected to have high IRAS fluxes and low background levels.
These Lockman Hole (LH) data represent a preliminary analysis of the deep 2MASS observations of this region, and are not a product endorsed by the 2MASS project. These data are described in The Astronomical Journal, Volume 125, Issue 5, pp. 2521-2530 "A Deep 2MASS survey of the Lockman Hole" by Beichman et al.
This all sky mosaic was created by Axel Mellinger and is used
in <i>SkyView</i> with his permission. A fuller description
is available at the
<a href="https://www.milkywaysky.com/">survey website</a>.
<p>
Between October 2007 and August 2009 a digital all-sky mosaic
was assembled from more than 3000 individual CCD frames.
Using an SBIG STL-11000 camera, 70 fields (each covering 40x27 degrees)
were imaged from dark-sky locations in South Africa, Texas and Michigan.
In order to increase the dynamic range beyond the 16 bits of the camera's
analog-to-digital converter (of which approximately 12 bits provide data
above the noise leve) three different exposure times (240s, 15s and 0.5 s)
were used. Five frames were taken for each exposure time and
filter setting. The frames were photometrically calibrated using
standard catalog stars and sky background data
from the Pioneer 10 and 11 space probes. the panorama has an
image scale of 36"/pixel and a limiting magnitude of approximately 14. The
survey has an 18 bit dynamic range.
<p>
The processing of these data used a custom data pipeline built using
IRAF, Source Extractor and SWarp.
<p>
The data used here were converted to three independent RGB color planes
of 8 bits each and provided to SkyView as a single 36000x18000x3 Cartesian
projection cube.
To allow users to efficiently sample data in a region of the sky,
this cube was broken up into 2100x2100 pixel regions with a 50 pixel overlap
between adjacent images. Tiles at the poles were 2100x2050.
<p>
In <i>SkyView</i> each color plane comprises a survey. The individual planes may be
sampled as surveys independently as Mellinger-R, Mellinger-G and Mellinger-B.
The color mosaics can be regenerated by creating an RGB image of all three
surveys. Since <i>SkyView</i> may stretch the intensity values within
each color, linear scaling and a minimum of 0 and maximum of 255 should
be specified to keep the original intensity scalings.
<p>
The full spatial resolution data is used for images of less than
30 degrees on a side. If a user requests a larger region, data are sampled
from a lower resolution 3600x1800x3 data cube. Please contact the survey
author if you need to use the higher resolution data for larger regions.
The Mellinger survey is only available in
<i>SkyView</i> through the website. SkyView-in-a-Jar cannot access
the underlying data. Provenance: Axel Mellinger. This is a service of NASA HEASARC.
The 4850MHz data is a
combination of data from three different surveys: Parkes-MIT-NRAO (PMN)
Southern (-88&#176;; to -37&#176;; declination) and tropical surveys (-29&#176;;
to -9&#176;; declination, and (86+87) Green Bank survey (0&#176;; to +75&#176;;
declination). The data contains gaps between -27&#176;; to -39&#176;;,
-9&#176;; to 0&#176;;, and
+77&#176;; to +90&#176;; declination.
The 4850MHz survey data were obtained by tape from J.J. Condon and are comprised
of 576 images and are used by permission. Full information pertaining to
these surveys are found in the references.<P> Provenance: NRAO, generated by J.J. Condon, J.J. Broderick and G.A. Seielstad, Douglas, K., and Gregory, P.C.. This is a service of NASA HEASARC.
Centro de Estudios de Física del Cosmos de Aragón (CEFCA)
Description:
MINIJ-PAS PDR201912 Catalogue (December, 2019) is based on scientific images in 60 filters covering a total area of ~1 square degree. MiniJ-PAS is a 60-band photometric optical survey based on images collected by the JST250 telescope and the Pathfinder instrument at the Observatorio Astrofísico de Javalambre (OAJ, Teruel, Spain) . Please include the following in any published material that makes use of this data: "Based on observations made with the JST250 telescope and PathFinder camera for Mini J-PAS project at the Observatorio Astrofísico de Javalambre, in Teruel, owned, managed and operated by the Centro de Estudios de Física del Cosmos de Aragón."
The MIPS Local Galaxies program compiles the Spitzer MIPS observations of all available galaxies in several Herschel-SPIRE Local Galaxies Guaranteed Time Programs, including the Very Nearby Galaxies Survey (VNGS), Dwarf Galaxy Survey (DGS), Herschel Reference Survey (HRS), and Herschel Virgo Cluster Survey (HeViCS).