Search

Start Over Subject surveys
431. 7C survey of radio sources at 151 MHz
ID:
ivo://CDS.VizieR/J/MNRAS/246/110
Title:
7C survey of radio sources at 151 MHz
Short Name:
J/MNRAS/246/110
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 7C survey of radio sources is being made with the Cambridge Low-Frequency Synthesis Telescope at 151MHz, with an angular resolution of 70x70cosec{delta}.arcsec^2^. We present the results from one part of of this survey covering 0.144sr in two areas of sky centred at RA=10h28min, DE=41{deg} and RA=06h28min, DE=45{deg} and reaching a limiting flux density of 50mJy. A list of the positions, flux densities and angular sizes of 4723 sources is presented; the position errors are in the range 1-3arcsec for sources with flux densities greater than 500mJy, and the flux density errors are typically 18mJy. About 10 per cent of the sources have apparent angular sizes greater than 60arcsec. The derived source counts are as accurate as those presently available at 405 and 1400MHz and show similar behaviour; in particular the convergence slopes are the same. The median spectral index between 151 and 408MHz remains constant at ~0.9 between 10 and 0.5Jy at 151MHz.
432. 6C Survey of radio sources I.
ID:
ivo://CDS.VizieR/VIII/18
Title:
6C Survey of radio sources I.
Short Name:
VIII/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 6th Cambridge Survey of radio sources covers most of the sky north of Dec>30{deg} with an angular resolution of 4.2x4.2cosec{delta} arcmin^2^ and a limiting flux density of 120mJy at 151MHz. This paper, the first of a series, describes the telescope and the methods used to produce the survey maps and source list, and presents maps of a circular area of radius 10{deg} centered on the North Celestial Pole and a list of 1761 sources north of {delta}>+80{deg}.
433. 6C Survey of radio sources - II.
ID:
ivo://CDS.VizieR/VIII/21
Title:
6C Survey of radio sources - II.
Short Name:
VIII/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 6th Cambridge survey of radio sources covers most of the sky north of +30{deg} with an angular resolution of 4.2x4.2cosec{delta}arcmin^2^ and reaches a limiting flux density of 190mJy at 151MHz in the present zone. In this paper the methods used to produce the survey maps from a non-tracking telescope operating at declinations other than the north celestial pole are described: this forms the basis for all future papers in the series. Maps of a high galactic latitude region are presented 30{deg}<{delta}<51{deg}, 08h30m<{alpha}<17h30m, together with a list of 8278 sources in the 2030deg^2^ covered. A source count over the range 200mJy<S(151)<100Jy is derived.
434. 6C Survey of Radio Sources - III.
ID:
ivo://CDS.VizieR/VIII/22
Title:
6C Survey of Radio Sources - III.
Short Name:
VIII/22
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 6th Cambridge Survey of radio sources covers most of the sky north of 30{deg} with an angular resolution of 4.2x4.2cosec{delta} arcmin^2^ and a limiting flux density of 160mJy at 151MHz, with completeness achieved at 600mJy. This paper presents 8749 sources in the 1950deg^2^ region 48{deg}<{delta}<68{deg}, 05h25m<{alpha}<18h17m.
435. 6C Survey of radio sources - IV.
ID:
ivo://CDS.VizieR/VIII/23
Title:
6C Survey of radio sources - IV.
Short Name:
VIII/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 6th Cambridge Survey of radio sources covers most of the sky north of 30{deg} with an angular resolution of 4.2x4.2cosec{delta} arcmin^2^ and a limiting flux density of 160mJy at 151MHz, with completeness achieved at 600mJy. This zone covers the declinations 67{deg}--82{deg} region 48{deg}<{delta}<68{deg}, 05h25m<{alpha}<18h17m.
436. 6C Survey of Radio Sources - V.
ID:
ivo://CDS.VizieR/VIII/24
Title:
6C Survey of Radio Sources - V.
Short Name:
VIII/24
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 6th Cambridge Survey of radio sources covers most of the sky north of 30{deg} with an angular resolution of 4.2x4.2cosec{delta} arcmin^2^ and a limiting flux density of 160mJy at 151MHz, with completeness achieved at 600mJy. This paper presents, in the declination ranges 48{deg}<{delta}<68{dec} the zones Va (01h34<{alpha}<06h14) and Vb (17h16<{alpha}<20h24)
437. 6C Survey of radio sources - VI.
ID:
ivo://CDS.VizieR/VIII/25
Title:
6C Survey of radio sources - VI.
Short Name:
VIII/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
See the documentation by N. A. Oliversen, either in LaTeX (doc.tex), or in plain ascii (adc.doc)
438. CTIO/DECam LCs for Galactic bulge variable stars
ID:
ivo://CDS.VizieR/J/ApJ/892/112
Title:
CTIO/DECam LCs for Galactic bulge variable stars
Short Name:
J/ApJ/892/112
Date:
21 Oct 2021
Publisher:
CDS
Description:
With the advent of the Legacy Survey of Space and Time, time-domain astronomy will be faced with an unprecedented volume and rate of data. Real-time processing of variables and transients detected by such large-scale surveys is critical to identifying the more unusual events and allocating scarce follow-up resources efficiently. We develop an algorithm to identify these novel events within a given population of variable sources. We determine the distributions of magnitude changes (dm) over time intervals (dt) for a given passband f, p_f_^(dm|dt)^, and use these distributions to compute the likelihood of a test source being consistent with the population or being an outlier. We demonstrate our algorithm by applying it to the DECam multiband time-series data of more than 2000 variable stars identified by Saha+ (2019, J/ApJ/874/30) in the Galactic Bulge that are largely dominated by long-period variables and pulsating stars. Our algorithm discovers 18 outlier sources in the sample, including a microlensing event, a dwarf nova, and two chromospherically active RS CVn stars, as well as sources in the blue horizontal branch region of the color-magnitude diagram without any known counterparts. We compare the performance of our algorithm for novelty detection with the multivariate Kernel Density Estimator and Isolation Forest on the simulated PLAsTiCC data set. We find that our algorithm yields comparable results despite its simplicity. Our method provides an efficient way for flagging the most unusual events in a real-time alert-broker system.
439. CUYS survey of Ha+NII ELG galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/359/930
Title:
CUYS survey of Ha+NII ELG galaxies
Short Name:
J/MNRAS/359/930
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the CIDAUCMYale (Centro de Investigaciones de Astronomia, Universidad Complutense de Madrid, and Yale University) Survey (CUYS) for H{alpha}+[NII] 6549, 6584{AA} emission-line galaxies (ELGs) using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically confirmed ELGs in a sky area of 151deg^2^ and redshift up to 0.14. We determine the parameters of the H{alpha} luminosity function using the H{alpha}+[NII] flux directly measured on the ELG spectra in this sample, and the star formation rate density derived is in agreement with values reported in the literature.
440. Danks 1, Danks 2, and RCW 79 variables
ID:
ivo://CDS.VizieR/J/A+A/545/A54
Title:
Danks 1, Danks 2, and RCW 79 variables
Short Name:
J/A+A/545/A54
Date:
21 Oct 2021
Publisher:
CDS
Description:
The ESO Public Survey "VISTA Variables in the Via Lactea"' (VVV) provides deep multi-epoch infrared observations for unprecedented 562 sq. degrees of the Galactic bulge, and adjacent regions of the disk. The VVV observations will foster the construction of a sample of Galactic star clusters with reliable and homogeneously derived physical parameters (e.g., age, distance, and mass, etc.). In this first paper in a series, the methodology employed to establish cluster parameters for the envisioned database are elaborated upon by analysing four known young open clusters: Danks1, Danks2, RCW79, and DBS132. The analysis offers a first glimpse of the information that can be gleaned from the VVV observations for clusters in the final database. Wide-field, deep JHK_s_ VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters for a subset of clusters. Results are inferred from VVV near-infrared photometry and numerous low resolution spectra (typically more than 10 per cluster). The high quality of the spectra and the deep wide-field VVV photometry enables us to precisely and independently determine the characteristics of the clusters studied, which we compare to previous determinations. An anomalous reddening law in the direction of the Danks clusters is found, specifically E(J-H)/E(H-Ks)=2.20+/-0.06, which exceeds published values for the inner Galaxy. The G305 star forming complex, which includes the Danks clusters, lies beyond the Sagittarius-Carina spiral arm and occupies the Centaurus arm. Finally, the first deep infrared colour-magnitude diagram of RCW79 is presented, which reveals a sizeable pre-main sequence population. A list of candidate variable stars in G305 region is reported. This study demonstrates the strength of the dataset and methodology employed, and constitutes the first step of a broader study which shall include reliable parameters for a sizeable number of poorly characterised and/or newly discovered clusters.

Limit your search

more »

more »

more »

more »

  • 22,418
  • 31

more »