scholarly journals Results from the Second EUVE Source Catalog

1996 ◽  
Vol 152 ◽  
pp. 5-6
Author(s):  
M. Lampton ◽  
S. Bowyer ◽  
J. Lewis ◽  
X. Wu ◽  
P. Jelinsky ◽  
...  
Keyword(s):  
Extragalactic Object ◽  
Sky Survey ◽  
Deep Survey

We present the results of the Second EUVE Source Catalog, including all detections from the EUVE all-sky survey, the EUVE deep survey, and sources detected during dedicated instrument pointings. Where available, we furnish identifications of these objects and statistics with regard to type of stellar or extragalactic object.

scholarly journals Faint Standards for ZYJHK from the UKIDSS and VISTA Surveys

2020 ◽  
Vol 493 (2) ◽  
pp. 2568-2595
Author(s):  
S K Leggett ◽  
Nicholas J G Cross ◽  
Nigel C Hambly
Keyword(s):  
Near Infrared ◽  
Variable Stars ◽  
Calibration Data ◽  
Infrared Telescope ◽  
Final Sample ◽  
Sky Survey ◽  
Data Release ◽  
Deep Survey ◽  
Large Telescopes ◽  
Astrometric Data

ABSTRACT The currently defined ‘United Kingdom Infrared Telescope (UKIRT) Faint Standards’ have JHK magnitudes between 10 and 15, with Kmedian = 11.2. These stars will be too bright for the next generation of large telescopes. We have used multi-epoch observations taken as part of the UKIRT Infrared Deep Sky Survey (UKIDSS) and the Visible and Infrared Survey Telescope for Astronomy (VISTA) surveys to identify non-variable stars with JHK magnitudes in the range 16–19. The stars were selected from the UKIDSS Deep Extragalactic Survey and Ultra Deep Survey, the WFCAM calibration data (WFCAMCAL08B), the VISTA Deep Extragalactic Observations (VIDEO), and UltraVISTA. Sources selected from the near-infrared databases were paired with the Pan-STARRS Data Release 2 of optical to near-infrared photometry and the Gaia astrometric Data Release 2. Colour indices and other measurements were used to exclude sources that did not appear to be simple single stars. From an initial selection of 169 sources, we present a final sample of 81 standard stars with ZYJHK magnitudes, or a subset, each with 20 to 600 observations in each filter. The new standards have Ksmedian = 17.5. The relative photometric uncertainty for the sample is <0.006 mag and the absolute uncertainty is estimated to be ≲ 0.02 mag. The sources are distributed equatorially and are accessible from both hemispheres.

scholarly journals Pilot pulsar surveys with LOFAR

2012 ◽  
Vol 8 (S291) ◽  
pp. 229-232
Author(s):  
Thijs Coenen
Keyword(s):  
Northern Hemisphere ◽  
Pilot Survey ◽  
Early Results ◽  
Sky Survey ◽  
Deep Survey

AbstractWe are performing two complementary pilot pulsar surveys as part of LOFAR commissioning. The LOFAR Pilot Pulsar Survey (LPPS) is a shallow all-sky survey using an incoherent combination of LOFAR stations. The LOFAR Tied-Array Survey (LOTAS) is a deeper pilot survey using 19 simultaneous tied-array beams. These will inform a forthcoming deep survey of the entire northern hemisphere, which is expected to discover hundreds of pulsars. Here we present early results from LPPS and LOTAS, among which are two independent pulsar discoveries.

scholarly journals Long-term NIR variability in the UKIDSS Ultra Deep Survey: a new probe of AGN activity at high redshift

2020 ◽  
Vol 493 (2) ◽  
pp. 3026-3035 ◽  
Author(s):  
E Elmer ◽  
O Almaini ◽  
M Merrifield ◽  
W G Hartley ◽  
D T Maltby ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
X Ray ◽  
X Ray Imaging ◽  
Sky Survey ◽  
Deep Survey ◽  
Stellar Masses

ABSTRACT We present the first attempt to select active galactic nuclei (AGN) using long-term near-infrared (NIR) variability. By analysing the K-band light curves of all the galaxies in the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra Deep Survey, the deepest NIR survey over ∼1 deg2, we have isolated 393 variable AGN candidates. A comparison to other selection techniques shows that only half of the variable sources are also selected using either deep Chandra X-ray imaging or Infrared Array Camera (IRAC) colour selection, suggesting that using NIR variability can locate AGN that are missed by more standard selection techniques. In particular, we find that long-term NIR variability identifies AGN at low luminosities and in host galaxies with low stellar masses, many of which appear relatively X-ray quiet.

scholarly journals A 6-CM Deep Sky Survey

1983 ◽  
Vol 104 ◽  
pp. 81-81
Author(s):  
E. B. Fomalont ◽  
K. I. Kellermann ◽  
J. V. Wall
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
Small Region ◽  
Sky Survey ◽  
Deep Survey

In order to extend radio source counts to lower flux density, we have used the VLA to survey a small region of sky at 4.885 GHz (6 cm) to a limiting flux density of 50 μJy. Details of this deep survey are given in the paper by Kellermann et al. (these proceedings). In addition, we have observed 10 other nearby fields to a limiting flux density of 350 μJy in order to provide better statistics on sources of intermediate flux density.

scholarly journals The Molonglo Deep Sky Survey of Radio Sources. II. Declination Zone -62°

1977 ◽  
Vol 30 (2) ◽  
pp. 231 ◽  
Author(s):  
JG Robertson
Keyword(s):  
Flux Density ◽  
Lower Limit ◽  
Solid Angle ◽  
Radio Sources ◽  
Upper Limit ◽  
Sky Survey ◽  
Deep Survey ◽  
The Right

Results are given for the second zone of a deep survey made at 408 MHz with the Molonglo cross. The catalogue lists positions and flux densities for 95 sources, none of which has been previously catalogued, in a solid angle of 5�51 x 10-3 sr. The right ascensions covered (with some excluded areas) are 18h 26m-OOh 06m, with a range in declination of 45'. The lower limit of flux density is 84 inJy. An upper limit of 1000 mJy has also been imposed. The position uncertainties are typically 12''at 100 mJy and 6# at 250 mJy.

scholarly journals Searching EUVE Data for Transient/Flaring Extreme Ultraviolet Sources

1996 ◽  
Vol 152 ◽  
pp. 481-484
Author(s):  
J. Lewis ◽  
S. Bowyer ◽  
M. Lampton ◽  
X. Wu ◽  
M. Mathioudakis
Keyword(s):  
Extreme Ultraviolet ◽  
Astrophysical Interest ◽  
Sky Survey ◽  
Deep Survey ◽  
Survey Strategy ◽  
Initial Survey ◽  
Lower Limits

The Extreme Ultraviolet Explorer (EUVE), because of its sky survey strategy, performed two observations of each point along a 180° by 1° strip of the ecliptic during the initial survey phase of the mission. One observation used the deep survey telescope, and another, 90 days earlier or later, used the all sky scanner telescopes, two of which have a nearly identical passband to that of the ecliptic deep survey. Since the completion of the initial sky survey, EUVE has been used to carry out deep, pointed observations of selected targets. Many areas of the sky have therefore been observed two or more times, allowing us to compare count rates for some objects over a long temporal baseline. Objects with significantly varying count rates for widely separated times are of particular astrophysical interest.With this technique, we have discovered one such object, which appears in the First EUVE Source Catalog as EUVE J2056-171. We present upper and lower limits on how frequently other highly-variable objects will be detected by EUVE in future observations.

scholarly journals Finding the Bivariate Brightness Distribution of Galaxies from an HI Selected Sample

1999 ◽  
Vol 16 (1) ◽  
pp. 12-17 ◽  
Author(s):  
R. F. Minchin
Keyword(s):  
Surface Brightness ◽  
Brightness Distribution ◽  
Selection Effects ◽  
Data Cubes ◽  
Real Noise ◽  
Sky Survey ◽  
Uniform Sample ◽  
Deep Survey ◽  
Survey Results ◽  
Optical Wavelengths

AbstractA method is presented that will enable the bivariate luminosity/surface brightness distribution of galaxies to be determined from a relatively small HI selected sample. This will be taken from the HI Parkes All Sky Survey (HIPASS). The advantages of using an HI sample in order to avoid the selection effects that are present at optical wavelengths are discussed. We are developing an algorithm to automatically extract a uniform sample of galaxies from the HIPASS data cubes and to determine the parameters of these galaxies. We have so far conducted tests involving both simulated sources injected into cubes with real noise and data from the Multibeam Deep survey. Results from these tests are encouraging.

scholarly journals The Molonglo Deep Sky Survey of Radio Sources. I. Declination Zone -20°

1977 ◽  
Vol 30 (2) ◽  
pp. 209 ◽  
Author(s):  
JG Robertson
Keyword(s):  
Error Analysis ◽  
Flux Density ◽  
Lower Limit ◽  
Solid Angle ◽  
Radio Sources ◽  
Contour Maps ◽  
Upper Limit ◽  
Sky Survey ◽  
Deep Survey

Results of a deep survey made at 408 MHz with the Molonglo cross are given. The catalogue lists positions and flux densities for a total of 373 radio sources, most of which have not previously been catalogued, in a solid angle of 0�0201 Sf. This covers (with some excluded areas) right ascensions 0l h oom-06h 44m and 13h 45m-17h 19m, with a range in declination of 41'. Eighteen contour maps are given of sources that are extended or have very close companions. A thorough error analysis is given, as well as new operational definitions of completeness and reliability. The lower limit of flux density is 88 mJy, which is five times the r.m.s. error. An upper limit of 1000 mJy has also been imposed. Typical errors in positions are 15" at 100 mJy and 6" at 250 mJy.

Radio and Optical Spectra of Sources from the Molonglo Deep Survey

1977 ◽  
Vol 3 (2) ◽  
pp. 142-143
Author(s):  
H. S. Murdoch ◽  
G. L. White
Keyword(s):  
Flux Density ◽  
Optical Spectra ◽  
Small Areas ◽  
Preliminary Results ◽  
Position Errors ◽  
Sky Survey ◽  
Deep Survey ◽  
Optical Identifications

We present here preliminary results of further radio and optical work being carried out on the Molonglo Deep Survey (Robertson 1977a, b, c) which reaches a density of ∼ 20,000 sources per sterad at a limiting flux density of 84 mJy at 408 MHz in three small areas of sky at declinations -20° and -62°. The position errors range from 4 to 15 arc sec r.m.s. depending on flux density. Optical identifications are being made by G. W. using the Palomar Sky Survey in the -20° region and the ESO and SRC surveys in the -62° region. In the latter case, where only one colour is available more accurate positions are necessary to identify QSO candidates. The Fleurs synthesis telescope is being used to obtain accurate positions.

scholarly journals TheEUVEOptical Identification Campaign II: Late-Type and White Dwarf Stars

1996 ◽  
Vol 152 ◽  
pp. 491-496
Author(s):  
N. Craig ◽  
A. Fruscione ◽  
J. Dupuis ◽  
M. Mathioudakis ◽  
J.J. Drake ◽  
...  
Keyword(s):  
White Dwarf ◽  
Extreme Ultraviolet ◽  
Late Type ◽  
Dwarf Stars ◽  
White Dwarf Stars ◽  
Sky Survey ◽  
Deep Survey ◽  
Balmer Lines ◽  
Optical Identifications ◽  
Error Circle

We present optical identifications of nine previously unidentified extreme ultraviolet (EUV) sources discovered during theExtreme Ultraviolet Explorer(EUVE) satellite surveys. The all-sky survey detected four of the sources and the more sensitive deep survey detected the other five sources. Three of the four all-sky survey sources, EUVE_J1918+59.9, EUVE_J2249+58.5, and EUVE_J2329+41.4, are listed in present catalogs as having possible associations with optical counterparts but without spectral class. The first two of these sources are hot DA white dwarfs showing an optical spectrum with broad Balmer lines. The source EUVE_J2329+41.4 is listed as having a possible association with an unclassified M star. We show that a pair of dMe stars are actually optical counterparts located within the error circle of theEUVEsource position. The EUVE_J2114+503 remains unidentified even though all the possible candidates have been studied. Based on the count rates we predict a fainter white dwarf or a cataclysmic variable counterpart for this candidate. All five sources discovered with theEUVEdeep survey, EUVE_J0318+184, EUVE_J0419+217, EUVE_J2053−175, EUVE_J2056−171 and EUVE_J2233−096, have been identified as late-type stars. The spectral classes, distances, visual magnitudes, and estimated hydrogen column densities for theseEUVEsources are presented.

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