- ID:
- ivo://CDS.VizieR/VIII/89
- Title:
- Northern HI Parkes All Sky Survey Catalogue (HIPASS)
- Short Name:
- VIII/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Northern HIPASS catalogue (NHICAT) is the northern extension of the HIPASS catalogue, HICAT. This extension adds the sky area between the declination (Dec.) range of +2{deg}<DE<+25{deg}30' to HICAT's Dec. range of -90{deg}<DE<+2{deg}. HIPASS is a blind HI survey using the Parkes Radio Telescope covering 71 per cent of the sky (including this northern extension) and a heliocentric velocity range of -1280 to 12700km/s. The entire Virgo Cluster region has been observed in the Northern HIPASS. The galaxy catalogue, NHICAT, contains 1002 sources with v_hel_>300km/s. Sources with -300<v_hel_<300km/s were excluded to avoid contamination by Galactic emission. In total, the entire HIPASS survey has found 5317 galaxies identified purely by their HI content. The full galaxy catalogue is publicly available at http://hipass.aus-vo.org.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/125/2064
- Title:
- Northern Optical Cluster Survey. II.
- Short Name:
- J/AJ/125/2064
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new, objectively defined catalog of candidate galaxy clusters based on the galaxy catalogs from the digitized Second Palomar Observatory Sky Survey. This cluster catalog, derived from the best calibrated plates in the high-latitude (|b|>30{deg}) northern Galactic cap region, covers 5800deg^2^ and contains 8155 candidate clusters. A simple adaptive kernel density mapping technique, combined with the SExtractor object detection algorithm, is used to detect galaxy overdensities, which we identify as clusters. Simulations of the background galaxy distribution and clusters of varying richnesses and redshifts allow us to optimize detection parameters and measure the completeness and contamination rates for our catalog. Cluster richnesses and photometric redshifts are measured, using integrated colors and magnitudes for each cluster. An extensive spectroscopic survey is used to confirm the photometric results. This catalog, with well-characterized sample properties, provides a sound basis for future studies of cluster physics and large-scale structure.
- ID:
- ivo://CDS.VizieR/J/AJ/137/2981
- Title:
- Northern Optical Cluster Survey. III.
- Short Name:
- J/AJ/137/2981
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the complete galaxy cluster catalog from the Northern Sky Optical Cluster Survey, a new, objectively defined catalog of candidate galaxy clusters at z<~0.25 drawn from the Digitized Second Palomar Observatory Sky Survey (DPOSS). The data presented here cover the Southern Galactic Cap, as well as the less well-calibrated regions of the Northern Galactic Cap. In addition, due to improvements in our cluster finder and measurement methods, we provide an updated catalog for the well-calibrated Northern Galactic Cap region previously published in Paper II (Cat. J/AJ/125/2064). The complete survey covers 11411deg^2^, with over 15000 candidate clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1017
- Title:
- Northern Optical Cluster Survey. IV.
- Short Name:
- J/AJ/128/1017
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an optically selected galaxy cluster catalog from 2700{deg}^2^ of the digitized Second Palomar Observatory Sky Survey (DPOSS), spanning the redshift range 0.1~<z~<0.5, providing an intermediate-redshift supplement to the previous DPOSS cluster survey. This new catalog contains 9956 cluster candidates and is the largest resource of rich clusters in this redshift range to date.
- ID:
- ivo://CDS.VizieR/II/287
- Title:
- Northern Sky Variability Survey (NSVS)
- Short Name:
- II/287
- Date:
- 23 Nov 2021 00:31:33
- Publisher:
- CDS
- Description:
- The Northern Sky Variability Survey (NSVS) is a temporal record of the sky over the optical magnitude range from 8 to 15.5. It was conducted in the course of the first-generation Robotic Optical Transient Search Experiment (ROTSE-I) using a robotic system of four comounted unfiltered telephoto lenses equipped with CCD cameras. The survey was conducted from Los Alamos, New Mexico, and primarily covers the entire northern sky. Some data in southern fields between declinations 0{deg} and -38{deg} are also available, although with fewer epochs and noticeably lesser quality. The NSVS contains light curves for approximately 14 million objects. With a 1-yr baseline and typically 100-500 measurements per object, the NSVS is the most extensive record of stellar variability across the bright sky available today. In a median field, bright unsaturated stars attain a point-to-point photometric scatter of ~0.02mag and position errors within 2. At Galactic latitudes |b|<20{deg}, the data quality is limited by severe blending due to the ~14" pixel size. We present basic characteristics of the data set and describe data collection, analysis, and distribution. All NSVS photometric measurements are available for on-line public access from the Sky Database for Objects in Time-Domain (SkyDOT) at Los Alamos National Laboratory. Copies of the full survey photometry may also be requested on tape.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/110
- Title:
- Northern XMM-XXL field AGN catalog
- Short Name:
- J/MNRAS/457/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a survey of X-ray-selected active galactic nuclei (AGNs) with optical spectroscopic follow-up in a ~18deg^2^ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by XMM-Newton above a limiting flux of F_0.5-10keV_>10^-15^erg/cm2/s was matched to optical (Sloan Digital Sky Survey, SDSS) and infrared (IR; WISE) counterparts. We followed up 3042 sources brighter than r=22.5mag with the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) spectrograph. The spectra yielded a reliable redshift measurement for 2578 AGNs in the redshift range z=0.02-5.0, with 0.5-2keV luminosities ranging from 10^39^-10^46^erg/s. This is currently the largest published spectroscopic sample of X-ray-selected AGNs in a contiguous area. The BOSS spectra of AGN candidates show a distribution of optical line widths which is clearly bimodal, allowing an efficient separation between broad- and narrow-emission line AGNs. The former dominate our sample (70 per cent) due to the relatively bright X-ray flux limit and the optical BOSS magnitude limit. We classify the narrow-emission line objects (22 per cent of the full sample) using standard optical emission line diagnostics: the majority have line ratios indicating the dominant source of ionization is the AGN. A small number (8 per cent of the full sample) exhibit the typical narrow line ratios of star-forming galaxies, or only have absorption lines in their spectra. We term the latter two classes 'elusive' AGN, which would not be easy to identify correctly without their X-ray emission. We also compare X-ray (XMM-Newton), optical colour (SDSS) and and IR (WISE) AGN selections in this field. X-ray observations reveal, by far, the largest number of AGN. The overlap between the selections, which is a strong function of the imaging depth in a given band, is also remarkably small. We show using spectral stacking that a large fraction of the X-ray AGNs would not be selectable via optical or IR colours due to host galaxy contamination. A substantial fraction of AGN may therefore be missed by these longer wavelength selection methods.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A6
- Title:
- NOT survey of subdwarf B stars
- Short Name:
- J/A+A/513/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search programme for pulsating subdwarf B stars was conducted with the Nordic Optical Telescope on La Palma over 59 nights between 1999 and 2009. The purpose of the programme was to significantly extend the number of rapidly pulsating sdB stars to better understand the properties of this new group of variable compact stars. Candidates were selected initially from the HS and HE surveys, but were supplemented with additional objects from other surveys. Short sequences of time-series photometry were made on the candidates to determine the presence of rapid pulsations.
- ID:
- ivo://CDS.VizieR/J/AJ/77/797
- Title:
- NRAO 5GHz Strong Source Survey
- Short Name:
- J/AJ/77/797
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 140-ft telescope at the National Radio Astronomy Observatory has been used to extend the 5-GHz strong source (S) survey over an area of 1.14 steradian. Some 240 sources have been detected in this region, of which 135 are above the completeness limit of 0.6f.u. The distribution of spectral indices for sources above the completeness limit is much broader than for samples selected from long-wavelength surveys, owing to an increase in the fraction of compact sources with flat spectra. For about half of the sources selected at 6 cm, the spectral index {alpha}>-0.5. Analysis of the dependence of the spectral index on the flux density shows that, as expected from the 408-MHz number counts and spectral index distribution, at 5 GHz there are fewer flat spectra among the weak sources than among the stronger ones. The spectral index distributions for the identified galaxies and quasars show the familiar forms: the galaxies have a strong concentration near {alpha}=-0.8 with a small tail extending toward flat spectra. The quasars show a much broader distribution of indices, but the fraction (80%) of quasars having flat spectra ({alpha}>-0.5) is much greater than that found in the low-frequency surveys. The number-flux density relation for various groups of sources selected from the 5-GHz survey show that the anomalously steep slope is confined to (a) unidentified sources, (b) sources with steep spectra ({alpha}<-0.5), and (c) sources located in the north galactic hemisphere. Sources identified with radio galaxies or quasars, or which have flat spectra, or which are in the south galactic hemisphere all show a number-flux density slope near -1.5.
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4878
- Title:
- Number counts predictions for surveys
- Short Name:
- J/MNRAS/472/4878
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the number counts of line emitters at high redshift and their evolution with cosmic time based on a combination of photometry and spectroscopy. We predict the H{alpha}, H{beta}, [OII], and [OIII] line fluxes for more than 35000 galaxies down to stellar masses of ~10^9^M_{sun}_ in the COSMOS and GOODS-S fields, applying standard conversions and exploiting the spectroscopic coverage of the FMOS-COSMOS survey at z~1.55 to calibrate the predictions. We calculate the number counts of H{alpha}, [OII], and [OIII] emitters down to fluxes of 1x10^-17^erg/cm^2^/s in the range 1.4<z<1.8 covered by the FMOS-COSMOS survey. We model the time evolution of the differential and cumulative H{alpha} counts, steeply declining at the brightest fluxes. We expect ~9300-9700 and ~2300-2900-galaxies/deg^2^ for fluxes >=1x10^-16^ and >=2x10^-16^erg/cm^2^/s over the range of 0.9<z<1.8. We show that the observed evolution of the main sequence of galaxies with redshift is enough to reproduce the observed counts variation at 0.2<z<2.5. We characterize the physical properties of the H{alpha} emitters with fluxes >=2x10^-16^erg/cm^2^/s including their stellar masses, UV sizes, [NII]/H{alpha} ratios and H{alpha} equivalent widths. An aperture of R~R_e_~0.5arcsec maximizes the signal-to-noise ratio for a detection, whilst causing a factor of ~2x flux losses, influencing the recoverable number counts, if neglected. Our approach, based on deep and large photometric data sets, reduces the uncertainties on the number counts due to the selection and spectroscopic samplings whilst exploring low fluxes. We publicly release the line flux predictions for the explored photometric samples.
- ID:
- ivo://CDS.VizieR/J/MNRAS/508/5176
- Title:
- NuSTAR Extragalactic Surveys, NEP Field
- Short Name:
- J/MNRAS/508/5176
- Date:
- 03 Dec 2021 13:27:09
- Publisher:
- CDS
- Description:
- We present the NuSTAR extragalactic survey of the James Webb Space Telescope (JWST) North Ecliptic Pole (NEP) Time-Domain Field. The survey covers a ~0.16deg^2^ area with a total exposure of 681ks acquired in a total of nine observations from three epochs. The survey sensitivities at 20% of the area are 2.39, 1.14, 2.76, 1.52, and 5.20x10^-14^erg/cm^2^/s in the 3-24, 3-8, 8-24, 8-16, and 16-24keV bands, respectively. The NEP survey is one of the most sensitive extragalactic surveys with NuSTAR so far. A total of 33 sources were detected above 95% reliability in at least one of the five bands. We present the number counts, logN-logS, measured in the hard X-ray 8-24 and 8-16keV bands, uniquely accessible by NuSTAR down to such faint fluxes. We performed source detection on the XMM-Newton and Chandra observations of the same field to search for soft X-ray counterparts of each NuSTAR detection. The soft band positions were used to identify optical and infrared associations. We present the X-ray properties (hardness ratio and luminosity) and optical-to-X-ray properties of the detected sources. The measured fraction of candidate Compton-thick (NH>=10^24^cm^-2^) active galactic nuclei, derived from the hardness ratio, is between 3% to 27%. As this survey was designed to have variability as its primary focus, we present preliminary results on multi-epoch flux variability in the 3-24keV band.
