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16251. u*g*r*i*z* Photometry of stars, galaxies, QSOs
ID:
ivo://CDS.VizieR/J/ApJS/123/377
Title:
u*g*r*i*z* Photometry of stars, galaxies, QSOs
Short Name:
J/ApJS/123/377
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog (table 5 of the paper) contains the measurements of 2262 sources, including 334 extended sources, 1915 point sources, and 13 known QSOs, in five passbands close to the u'g'r'i'z' passbands of SDSS (see the definition of the photometric system in Richards et al., 1997PASP..109...39R). Of these objects, over 1600 are measured in 15 fields covering 0.5deg^2^, with a limiting magnitude of r*<19.5, similar to the photometric limit of the SDSS spectroscopic survey.
16252. UGRK Photometry in the Hubble Deep field region
ID:
ivo://CDS.VizieR/J/ApJS/127/1
Title:
UGRK Photometry in the Hubble Deep field region
Short Name:
J/ApJS/127/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
Detection and photometry of sources in the U_n_, G, {R}, and K_s_ bands in a 9x9 arcmin^2^ region of the sky, centered on the Hubble Deep Field, are described. The data permit construction of complete photometric catalogs to roughly U_n_=25, G=26, {R}=25.5, K_s_=20 mag and significant photometric measurements somewhat fainter. Galaxy catalogs selected in the {R} and K_s_ bands are presented, containing 3607 and 488 sources in field areas of 74.8 and 59.4arcmin^2^, to {R}=25.5 and K_s_=20mag.
16253. UGR photometry of LBG candidates at z~3
ID:
ivo://CDS.VizieR/J/A+A/563/A142
Title:
UGR photometry of LBG candidates at z~3
Short Name:
J/A+A/563/A142
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a deep multi wavelength imaging survey (UGR) in 3 different fields, Q0933, Q1623 and COSMOS, for a total area of ~1500arcmin^2^ The data were obtained with the Large Binocular Camera on the Large Binocular Telescope. To select our LBG candidates we adopt the well established and widely used color selection criterion (U-G vs. G-R). One of the main advantages of our survey is that it has a wider dynamic color range for U drop-out selection compared to previous studies. This allows us to fully exploit the depth of our R band images, obtaining a robust sample with few interlopers. In addition, for 2 of our fields we have spectroscopic redshift information that is necessary to better estimate the completeness of our sample and interloper fraction. Our limiting magnitudes reach 27.0(AB) in the R band (5{sigma}) and 28.6(AB) in the U band (1{sigma}). This dataset was used to derive Lyman Break Galaxy candidates at z~3. We obtained a catalog with a total of 12264 sources down to the 50% completeness magnitude limit in the R band for each field. We find a surface density of ~3 LBG candidates arcmin^-2^ down to R=25.5, where completeness is >=95% for all 3 fields. This number is higher than the original studies, but consistent with more recent samples.
16254. UGSs. V. kernel approach
ID:
ivo://CDS.VizieR/J/ApJS/209/10
Title:
UGSs. V. kernel approach
Short Name:
J/ApJS/209/10
Date:
21 Oct 2021
Publisher:
CDS
Description:
Nearly one-third of the {gamma}-ray sources detected by Fermi are still unidentified, despite significant recent progress in this area. However, all of the {gamma}-ray extragalactic sources associated in the second Fermi-LAT catalog have a radio counterpart. Motivated by this observational evidence, we investigate all the radio sources of the major radio surveys that lie within the positional uncertainty region of the unidentified {gamma}-ray sources (UGSs) at a 95% level of confidence. First, we search for their infrared counterparts in the all-sky survey performed by the Wide-field Infrared Survey Explorer (WISE) and then we analyze their IR colors in comparison with those of the known {gamma}-ray blazars. We propose a new approach, on the basis of a two-dimensional kernel density estimation technique in the single [3.4]-[4.6]-[12]{mu}m WISE color-color plot, replacing the constraint imposed in our previous investigations on the detection at 22{mu}m of each potential IR counterpart of the UGSs with associated radio emission. The main goal of this analysis is to find distant {gamma}-ray blazar candidates that, being too faint at 22{mu}m, are not detected by WISE and thus are not selected by our purely IR-based methods. We find 55 UGSs that likely correspond to radio sources with blazar-like IR signatures. An additional 11 UGSs that have blazar-like IR colors have been found within the sample of sources found with deep recent Australia Telescope Compact Array observations.
16255. UHS DR2 - UKIRT Hemisphere Survey Data Release 2
ID:
ivo://wfau.roe.ac.uk/uhsDR2-dsa
Title:
UHS DR2 - UKIRT Hemisphere Survey Data Release 2
Date:
23 Jan 2024 09:45:50
Publisher:
WFAU, Institute for Astronomy, University of Edinburgh
Description:
This DSA hosts data release 2 of the UKIRT Hemisphere Survey housed at the Wide Field Astronomy Unit at the Univeristy of Edinburgh. The UHS provides continuous J and K-band coverage in the northern hemisphere from a declination of 0 deg to 60 deg.
16256. Uhuru Fourth (4U) Catalog
ID:
ivo://nasa.heasarc/uhuru4
Title:
Uhuru Fourth (4U) Catalog
Short Name:
UHURU4
Date:
28 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Fourth Uhuru (4U) Catalog lists 339 X-ray sources that were observed with the Uhuru (SAS A) X-ray observatory. It contains positional information in the form of 90% confidence level error boxes, 2-6 keV intensities, possible optical and radio counterparts, and alternative names for sources observed in earlier compilations. The major classes of identified objects include binary stellar systems, supernova remnants, Seyfert galaxies, clusters of galaxies, and possibly the new class of superclusters of galaxies. The Uhuru satellite was a scanning X-ray instrument with a narrow (1 by 10 degree FWFM) and a wide (10 by 10 degree FWFM) collimator (cf. Giacconi et al. 1971, ApJ, 165, L27). Typically, the scan rate was 0.5 degree/second, with the spin axis in one position for roughly one day. During the interval for which the spin axis was fixed, repeated scans were made of the same 10 by 360 degrees band of the sky. For this catalog, the individual scans were superposed using aspect data from an orthogonally mounted triad of magnetometers and a Sun sensor onboard the spacecraft, supplemented by observations of well-located X-ray sources. The observations employed in producing this catalog were obtained over a total of 429 days between 1970 December 12 and 1973 March 18, apart from a gap between 1972 July and December when the spacecraft&#39;s transmitter was operating improperly. This online catalog was created by the HEASARC in March 2003 based on a table obtained originally from the ADC website (&lt;a href="https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/uhuru4/4u.dat"&gt;https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/uhuru4/4u.dat&lt;/a&gt;), which was modified by the HEASARC to include some parameters that were in the published catalog (Table 1 in the reference) but were not in the ADC table. The HEASARC made a small number of other changes and corrections to the table which are listed in the HEASARC_Implementation section of this help. Notice that the ADC table itself differs in a number of respects from the published Table 1, e.g., the comments are sometimes abbreviated and/or different, some of the names are slightly different (usually by one digit in the RA minutes part), and three of the entries have differing names and positions. This is a service provided by NASA HEASARC .
16257. UIT near-UV bright objects catalog
ID:
ivo://CDS.VizieR/J/ApJS/104/287
Title:
UIT near-UV bright objects catalog
Short Name:
J/ApJS/104/287
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a photometric catalog of 2244 objects detected by the Ultraviolet Imaging Telescope in the near-ultraviolet (NUV; 1650A<lambda<2900A) during the Astro-1 Space Shuttle mission. Sources in the catalog are as faint as m_nuv~18.8, or f_nuv~1.1x10^-16ergs/s/cm^2/A, but the survey is not complete to this level. Optical catalogs were used to cross identify sources and derive NUV-V colors. A majority of the objects (88%) do indeed have proposed optical identifications from catalogs, and most are stars. Our purpose in creating the catalog is to form a database useful for identifying very blue objects and performing Galactic UV stellar population studies.
16258. u_j_br photometry and redshifts of QSOs
ID:
ivo://CDS.VizieR/J/MNRAS/341/993
Title:
u_j_br photometry and redshifts of QSOs
Short Name:
J/MNRAS/341/993
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed analysis of a sample of radio-detected quasars, obtained by matching together objects from the FIRST (<VIII/71>) survey and the 2dF Quasar Redshift Survey (2dF, <VII/223>). The data set consists of 113 sources, spanning a redshift range 0.35<~z<~2.2, with optical magnitudes 18.25<=bj<=20.85 and radio fluxes S_1.4GHz_>=1mJy. These objects exhibit properties such as redshift and colour distribution in full agreement with those derived for the whole quasar population, suggesting that the mechanism(s) controlling the birth and lifetime of quasars are independent of their level of radio emission. The long-debated question of the radio-loud/radio quiet (RL/RQ) dichotomy is then investigated for the combined FIRST-2dF and FIRST-LBQS (Large Bright Quasar Survey) samples, as they present similar selection criteria.
16259. UKIDSS-DR6 Galactic Plane Survey
ID:
ivo://CDS.VizieR/II/316
Title:
UKIDSS-DR6 Galactic Plane Survey
Short Name:
II/316
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UKIDSS Galactic Plane Survey (GPS) is one of the five near infrared Public Legacy Surveys that are being undertaken by the UKIDSS consortium, using the Wide Field Camera on the United Kingdom Infrared Telescope. It is surveying 1868 deg^2^ of the northern and equatorial Galactic plane at Galactic latitudes -5{deg}<b<5{deg} in the J, H and K filters and a ~300 deg^2^ area of the Taurus-Auriga-Perseus molecular cloud complex in these three filters and the 2.12{mu}m (1-0)S(1)H_2_ filter. It will provide data on ~ 3x10^9^ sources. The survey use the Wide Field Camera (WFCAM, see Casali et al. 2007A&A...467..777C) on the United Kingdom Infrared Telescope (UKIRT). The typical 90% completeness limits in uncrowded fields are K=18.0, H=18.75, J=19.5, with uncertainties of about 0.2mag.
16260. UKIDSS-DR7 Large Area Survey
ID:
ivo://CDS.VizieR/II/310
Title:
UKIDSS-DR7 Large Area Survey
Short Name:
II/310
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UKIRT Infrared Deep Sky Survey (UKIDSS) is a large-scale near-IR survey which aim is to cover 7500 square degrees of the Northern sky. The survey is carried out using the Wide Field Camera (WFCAM), with a field of view of 0.21 square degrees, mounted on the 3.8m United Kingdom Infra-red Telescope (UKIRT) in Hawaii. The Large Area Survey (LAS) covers an area of 4000 square degrees in high Galactic latitudes (extragalactic) in the four bands Y(1.0um) J(1.2um) H(1.6um) and K(2.2um) to a depth of K = 18.4. Details of the survey can be found in the in the paper by Lawrence et al. (2007MNRAS.379.1599L)

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