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 USco1621 B and USco1556 B: Two wide companions at the deuterium-burning mass limit in Upper Scorpius

2020 ◽  
Vol 633 ◽  
pp. A152 ◽  
Author(s):  
Patricia Chinchilla ◽  
Víctor J. S. Béjar ◽  
Nicolas Lodieu ◽  
Bartosz Gauza ◽  
Maria Rosa Zapatero Osorio ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Infrared Telescope ◽  
The United Kingdom ◽  
Sky Survey ◽  
Substellar Objects ◽  
Galactic Clusters ◽  
M Stars

Aims. Our objective is to identify analogues of gas giant planets, but located as companions at wide separations of very young stars. The main purpose is to characterise the binarity frequency and the properties of these substellar objects, and to elucidate their early evolutionary stages. Methods. To identify these objects, we cross correlated the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey and the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Clusters Survey catalogues to search for common proper motion companions to 1195 already known members of Upper Scorpius (USco; age ~5–10 Myr, distance ~145 pc). We present the discovery and spectroscopic characterisation of two very wide substellar companions of two early-M stars in Upper Scorpius: USco1621 B and USco1556 B. We obtained optical and near-infrared low-resolution spectroscopy of the candidates to characterise their spectral energy distribution and confirm their youth and membership to the association. We also acquired adaptive optics images of the primaries and secondaries to search for signs of binarity and close companions. Results. By comparison with field dwarfs and other young members of USco, we determined a spectral type of M8.5 in the optical for both companions, along with L0 and L0.5 in the near-infrared for USco1621 B and USco1556 B, respectively. The spectra of the two companions show evident markers of youth, such as weak alkaline Na I and K I lines, along with the triangular shape of the H-band. The comparison with theoretical evolutionary models gives estimated masses of 0.015 ± 0.002 and 0.014 ± 0.002 M⊙, with temperatures of 2270 ± 90 and 2240 ± 100 K, respectively. The physical separations between the components of both systems are 2880 ± 20 and 3500 ± 40 AU for USco1621 and USco1556 systems, respectively. We did not find any additional close companion in the adaptive optics images. The probability that the two secondaries are physically bound to their respective primaries, and not chance alignments of USco members, is 86%, and the probability that none of them are physically related is 1.0%.

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 The Sloan Digital Sky Survey Quasar Catalog: Fourteenth data release

2018 ◽  
Vol 613 ◽  
pp. A51 ◽  
Author(s):  
Isabelle Pâris ◽  
Patrick Petitjean ◽  
Éric Aubourg ◽  
Adam D. Myers ◽  
Alina Streblyanska ◽  
...  
Keyword(s):  
Emission Line ◽  
Near Infrared ◽  
Wavelength Region ◽  
Principal Component ◽  
Sloan Digital Sky Survey ◽  
Large Area ◽  
Robust Identification ◽  
Broad Absorption Line ◽  
Sky Survey ◽  
Data Release

We present the data release 14 Quasar catalog (DR14Q) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). This catalog includes all SDSS-IV/eBOSS objects that were spectroscopically targeted as quasar candidates and that are confirmed as quasars via a new automated procedure combined with a partial visual inspection of spectra, have luminosities Mi [z = 2] < −20.5 (in a Λ CDM cosmology with H0 = 70 km s−1 Mpc−1, Ω M =0.3, and Ω Λ = 0.7), and either display at least one emission line with a full width at half maximum larger than 500 km s−1 or, if not, have interesting/complex absorption features. The catalog also includes previously spectroscopically-confirmed quasars from SDSS-I, II, and III. The catalog contains 526 356 quasars (144 046 are new discoveries since the beginning of SDSS-IV) detected over 9376 deg2 (2044 deg2 having new spectroscopic data available) with robust identification and redshift measured by a combination of principal component eigenspectra. The catalog is estimated to have about 0.5% contamination. Redshifts are provided for the Mg II emission line. The catalog identifies 21 877 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u, g, r, i, z) CCD-based photometry with typical accuracy of 0.03 mag. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3610–10 140 Å at a spectral resolution in the range 1300 < R < 2500, can be retrieved from the SDSS Science Archiver Server.

scholarly journals The Two Micron All-Sky Survey: Removing the Infrared Foreground

2001 ◽  
Vol 204 ◽  
pp. 197-207
Author(s):  
John E. Gizis ◽  
Michael F. Skrutskie
Keyword(s):  
Near Infrared ◽  
High Reliability ◽  
Sky Survey ◽  
Data Release ◽  
Infrared Background ◽  
Infrared Survey

We introduce the properties of the Two Micron All-Sky Survey (2MASS) for IAU Symposium 204. 2MASS is a near-infrared survey of the entire sky characterized by high reliability and completeness. Catalogs and images for 47% of the sky are now available online. This data release has been used by Wright (2000) and Cambrésy et al. (2000) to subtract the stellar foreground at 1.25 and 2.2 microns from COBE DIRBE data, revealing the cosmological near-infrared background.

scholarly journals The United Kingdom Infrared Telescope Infrared Deep Sky Survey First Data Release

2007 ◽  
Vol 375 (1) ◽  
pp. 213-226 ◽  
Author(s):  
S. J. Warren ◽  
N. C. Hambly ◽  
S. Dye ◽  
O. Almaini ◽  
N. J. G. Cross ◽  
...  
Keyword(s):  
United Kingdom ◽  
Infrared Telescope ◽  
The United Kingdom ◽  
Sky Survey ◽  
Data Release

scholarly journals Near-infrared time-series photometry in the field of Cygnus OB2 association

2020 ◽  
Vol 640 ◽  
pp. A128
Author(s):  
J. Roquette ◽  
S. H. P. Alencar ◽  
J. Bouvier ◽  
M. G. Guarcello ◽  
B. Reipurth
Keyword(s):  
Near Infrared ◽  
Color Space ◽  
Variable Stars ◽  
Wide Field ◽  
Photometric Variability ◽  
Circumstellar Material ◽  
Infrared Telescope ◽  
The United Kingdom ◽  
Low Mass ◽  
Cold Spots

We present the results of a J, H, and K photometric variability survey of the central 0.78 square degrees of the young OB association Cygnus OB2. We used data observed with the Wide-Field CAMera at the United Kingdom Infrared Telescope in 2007 (spanning 217 days) to investigate the light curves of 5083 low mass candidate members in the association and explore the occurrence and main characteristics of their near-infrared variability. We identified 2529 stars (∼50% of the sample) with significant variability with time-scales ranging from days to months. We classified the variable stars into the following three groups according to their light curve morphology: periodic variability (1697 stars), occultation variability (124 stars), and other types of variability (726 stars). We verified that the disk-bearing stars in our sample are significantly more variable in the near-infrared than diskless stars, with a steep increase in the disk-fraction among stars with higher variability amplitude. We investigated the trajectories described by variable stars in the color-space and measured slopes for 335 stars describing linear trajectories. Based on the trajectories in the color-space, we inferred that the sample analyzed is composed of a mix of young stars presenting variability due to hot and cold spots, extinction by circumstellar material, and changes in the disk emission in the near-infrared. We contemplated using the use of near-infrared variability to identify disk-bearing stars and verified that 53.4% of the known disk-bearing stars in our sample could have been identified as such based solely on their variability. We present 18 newly identified disk-bearing stars and 14 eclipsing binary candidates among CygOB2 lower-mass members.

scholarly journals The second Herschel–ATLAS Data Release – III. Optical and near-infrared counterparts in the North Galactic Plane field

2018 ◽  
Vol 476 (1) ◽  
pp. 961-978 ◽  
Author(s):  
C Furlanetto ◽  
S Dye ◽  
N Bourne ◽  
S Maddox ◽  
L Dunne ◽  
...  
Keyword(s):  
Likelihood Ratio ◽  
Near Infrared ◽  
Galactic Plane ◽  
Ratio Method ◽  
Large Area ◽  
Sky Survey ◽  
Public Data ◽  
Data Release ◽  
North Galactic ◽  
Likelihood Ratio Method

Abstract This paper forms part of the second major public data release of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). In this work, we describe the identification of optical and near-infrared counterparts to the submillimetre detected sources in the 177 deg2 North Galactic Plane (NGP) field. We used the likelihood ratio method to identify counterparts in the Sloan Digital Sky Survey and in the United Kingdom InfraRed Telescope Imaging Deep Sky Survey within a search radius of 10 arcsec of the H-ATLAS sources with a 4σ detection at 250 μm. We obtained reliable (R ≥ 0.8) optical counterparts with r &lt; 22.4 for 42 429 H-ATLAS sources (37.8 per cent), with an estimated completeness of 71.7 per cent and a false identification rate of 4.7 per cent. We also identified counterparts in the near-infrared using deeper K-band data which covers a smaller ∼25 deg2. We found reliable near-infrared counterparts to 61.8 per cent of the 250-μm-selected sources within that area. We assessed the performance of the likelihood ratio method to identify optical and near-infrared counterparts taking into account the depth and area of both input catalogues. Using catalogues with the same surface density of objects in the overlapping ∼25 deg2 area, we obtained that the reliable fraction in the near-infrared (54.8 per cent) is significantly higher than in the optical (36.4 per cent). Finally, using deep radio data which covers a small region of the NGP field, we found that 80–90 per cent of our reliable identifications are correct.

scholarly journals Transformations from WISE to 2MASS, SDSS and BVI Photometric Systems: II. Transformation Equations for Red-Clump Stars

2012 ◽  
Vol 29 (2) ◽  
pp. 121-131 ◽  
Author(s):  
S. Bilir ◽  
S. Karaali ◽  
N. D. Dağtekin ◽  
Ö. Önal ◽  
S. Ak ◽  
...  
Keyword(s):  
Field Survey ◽  
Sloan Digital Sky Survey ◽  
Wide Field ◽  
Experiment Data ◽  
The Third ◽  
Final Sample ◽  
Sky Survey ◽  
Data Release ◽  
Red Clump ◽  
Absolute Magnitudes

AbstractWe present colour transformations for the conversion of Wide-Field Survey Explorer W1, W2, and W3 magnitudes to the Johnson–Cousins BVIc, Sloan Digital Sky Survey gri, and Two Micron All Sky Survey JHKs photometric systems, for red clump (RC) stars. RC stars were selected from the Third Radial Velocity Experiment Data Release. The apparent magnitudes were collected by matching the coordinates of this sample with different photometric catalogues. The final sample (355 RC stars) was used to obtain metallicitydependent and free-of-metallicity transformations. These transformations combined with known absolute magnitudes at shorter wavelengths can be used in space density determinations for the Galactic (thin and thick) discs at distances larger than the ones evaluated with JHKs photometry alone, hence providing a powerful tool in the analysis of Galactic structure.

Sign in / Sign up

Export Citation Format

Share Document