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2281. Water maser and NH_3_ survey of GLIMPSE EGOs
ID:
ivo://CDS.VizieR/J/ApJ/764/61
Title:
Water maser and NH_3_ survey of GLIMPSE EGOs
Short Name:
J/ApJ/764/61
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a Nobeyama 45m H_2_O maser and NH_3_ survey of all 94 northern GLIMPSE extended green objects (EGOs), a sample of massive young stellar objects (MYSOs) identified based on their extended 4.5{mu}m emission. We observed the NH_3_(1,1), (2,2), and (3,3) inversion lines, and detected emission toward 97%, 63%, and 46% of our sample, respectively (median rms~50mK). The H_2_O maser detection rate is 68% (median rms~0.11Jy). The derived H_2_O maser and clump-scale gas properties are consistent with the identification of EGOs as young MYSOs. To explore the degree of variation among EGOs, we analyze subsamples defined based on mid-infrared (MIR) properties or maser associations. H_2_O masers and warm dense gas, as indicated by emission in the higher-excitation NH_3_ transitions, are most frequently detected toward EGOs also associated with both Class I and II CH_3_OH masers. Ninety-five percent (81%) of such EGOs are detected in H_2_O (NH_3_(3,3)), compared to only 33% (7%) of EGOs without either CH_3_OH maser type. As populations, EGOs associated with Class I and/or II CH_3_OH masers have significantly higher NH_3_ line widths, column densities, and kinetic temperatures than EGOs undetected in CH_3_OH maser surveys. However, we find no evidence for statistically significant differences in H_2_O maser properties (such as maser luminosity) among any EGO subsamples. Combining our data with the 1.1mm continuum Bolocam Galactic Plane Survey, we find no correlation between isotropic H_2_O maser luminosity and clump number density. H_2_O maser luminosity is weakly correlated with clump (gas) temperature and clump mass.
2282. Water maser in galactic IRAS sources
ID:
ivo://CDS.VizieR/J/PASJ/59/1185
Title:
Water maser in galactic IRAS sources
Short Name:
J/PASJ/59/1185
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present H_2_O maser data from a survey toward IRAS sources in the Galaxy with the Nobeyama 45m telescope. This survey had a 1{sigma} noise level as small as 0.24Jy, resulting in one of the most sensitive water-maser surveys. The maximum distance of the masers to be detected by our survey is estimated to be 3kpc for sources with F_nu,1kpc_<10Jy and 10kpc for those with 10Jy<=F_nu,1kpc_<100Jy, where F_nu,1kpc_ is the maser flux density converted at a distance of 1kpc. For strong masers with F_nu,1kpc_>=100Jy, our survey could detect all sources in the Galaxy. We carried out a total of 2229 observations toward 1563 sources and detected water-maser emission toward 222 sources. Our survey newly found masers from 75 of the 222 sources.
2283. Water maser survey
ID:
ivo://CDS.VizieR/J/AJ/132/1322
Title:
Water maser survey
Short Name:
J/AJ/132/1322
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the most sensitive water maser survey toward Bok globules to date, performed using NASA's 70m antenna at Robledo de Chavela (Spain). We observed 207 positions within the Clemens and Barvainis catalog with a higher probability of harboring a young star, using as selection criteria the presence of radio continuum emission (from submillimeter to centimeter wavelengths), geometric centers of molecular outflows, peaks in maps of high-density gas tracers (NH3 or CS), and IRAS point sources. We have obtained seven maser detections, six of which (in CB 34, CB 54, CB 65, CB 101, CB 199, and CB 232) are reported for the first time here. Most of the water masers we detected are likely to be associated with young stellar objects (YSOs), except for CB 101 (probably an evolved object) and CB 65 (uncertain nature). The water maser in CB 199 shows a relatively high shift (30km/s) of its velocity centroid with respect to the cloud velocity, which is unusual for low-mass YSOs. We speculate that high-velocity masers in this kind of object could be related to episodes of energetic mass loss in close binaries. Alternatively, the maser in CB 199 could be pumped by a protoplanetary or a young planetary nebula. CB 232 is the smallest Bok globule (0.6pc) known to be associated with water maser emission, although it would be superseded by the cases of CB 65 (0.3pc) and CB 199 (0.5pc) if their association with YSOs is confirmed. All our selection criteria have statistically compatible detection rates, except for IRAS sources, which tend to be somewhat worse predictors for the presence of maser emission.
2284. WD luminosity functions from the PS1 3pi Survey
ID:
ivo://CDS.VizieR/J/MNRAS/482/715
Title:
WD luminosity functions from the PS1 3pi Survey
Short Name:
J/MNRAS/482/715
Date:
21 Oct 2021
Publisher:
CDS
Description:
A large sample of white dwarfs is selected by both proper motion and colours from the Pan-STARRS 1 3{pi} Steradian Survey Processing Version 2 to construct the white dwarf luminosity functions of the discs and halo in the solar neighbourhood. Four-parameter astrometric solutions were recomputed from the epoch data. The generalized maximum volume method is then used to calculate the density of the populations. After removal of crowded areas near the Galactic plane and centre, the final sky area used by this work is 7.833sr, which is 83 per cent of the 3{pi} sky and 62 per cent of the whole sky. By dividing the sky using Voronoi tessellation, photometric and astrometric uncertainties are recomputed at each step of the integration to improve the accuracy of the maximum volume. Interstellar reddening is considered throughout the work. We find a disc-to-halo white dwarf ratio of about 100.
2285. Westerbork Northern Sky Survey
ID:
ivo://nasa.heasarc/skyview/wenss
Title:
Westerbork Northern Sky Survey
Short Name:
WENSS
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Westerbork Northern Sky Survey (<i>WENSS</i>) is a low-frequency radio survey that covers the whole sky north of delta=30 degree at a wavelength of 92 cm to a limiting flux density of approximately 18 mJy (5 sigma). This survey has a resolution of 54" x 54" cosec (delta) and a positional accuracy for strong sources of 1.5''. <p> Further information on the survey including links to catalogs derived from the survey is available at the <a href="https://web.archive.org/web/20041204180313/http://www.strw.leidenuniv.nl/wenss/"><i>WENSS</i> website</a>. <p> The <i>WENSS</i> survey is included on the <b>SkyView High Resolution Radio Coverage </b><a href="https://skyview.gsfc.nasa.gov/images/high_res_radio.jpg"> map</a>. This map shows coverage on an Aitoff projection of the sky in equatorial coordinates. <p> Provenance: <i>WENSS</i> Team. Data downloaded from <a href=ftp://vliet.strw.leidenuniv.nl/pub/wenss/HIGHRES/> <i>WENSS</i> FTP site</a> 1999-03-18. The <i>WENSS</i> project is a collaboration between the <a href="https://www.astron.nl/astronomy/">Netherlands Foundation for Research in Astronomy</a> (NFRA/ASTRON) and the <a href="https://local.strw.leidenuniv.nl/">Leiden Observatory</a>.. This is a service of NASA HEASARC.
2286. Westerbork Second Deep Survey
ID:
ivo://CDS.VizieR/J/A+A/35/393
Title:
Westerbork Second Deep Survey
Short Name:
J/A+A/35/393
Date:
21 Oct 2021
Publisher:
CDS
Description:
A radio survey has been made of an area centered at 01h 03min +29{deg}, using the Westerbork telescope at 1415MHz. The completeness limit of the survey is 7mJy. Additional observations have been made at 610MHz. The Lick 120" telescope has been used to obtain deep (O98-O2 emulsion) plates to serve as an optical counterpart. A catalogue is presented of 58 sources found in the survey. 53 of these comprise a complete sample. 31 sources of the complete sample lie in areas of which Lick plates were taken. Of the sources in Lick plates areas, 11 could be identified with galaxies and 3 with possible QSO's, yielding an identification percentage of 46. For the other 22 sources an identification programme was carried out using Palomar Sky Survey prints and other large 48" Schmidt plates: three of these sources could be identified with galaxies and two with possible QSO's. The survey was also used to derive source counts and a spectral index distribution. The source counts agree well with those derived for an earlier survey. The spectral index distribution has a mean of 0.52 and a width of 0.39. the explanation for the flatter spectra is not clear but might possibly lie in another source population that begins to dominate the results at low flux densities.
2287. WHAM Northern Sky Survey, V-1.1
ID:
ivo://CDS.VizieR/II/249
Title:
WHAM Northern Sky Survey, V-1.1
Short Name:
II/249
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Wisconsin H-Alpha Mapper has been designed to produce a survey of H-Alpha emission from the interstellar medium (ISM) over the entire northern sky. The instrument combines a 0.6 meter telescope and a dual-etalon 15cm Fabry-Perot spectrometer. In the primary spectral mode, an exposure captures a 200km/s spectral region with 8-12km/s velocity resolution from a one-degree beam on the sky. With a large-aperture design and modern CCD technology, WHAM can detect Galactic emission as faint as 0.05 Rayleighs in a 30 second exposure. For gas at 10000K, this observed intensity corresponds to an emission measure of about 0.1cm^-6^pc, more than 10 million times fainter than the Orion Nebula.
2288. White dwarf candidates in DECam first field
ID:
ivo://CDS.VizieR/J/MNRAS/462/2506
Title:
White dwarf candidates in DECam first field
Short Name:
J/MNRAS/462/2506
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results from a minute cadence survey of a 3deg^2^ field obtained with the Dark Energy Camera. We imaged part of the Canada-France-Hawaii Telescope Legacy Survey area over eight half-nights. We use the stacked images to identify 111 high proper motion white dwarf candidates with g<=24.5mag and search for eclipse-like events and other sources of variability. We find a new g=20.64mag pulsating ZZ Ceti star with pulsation periods of 11-13min. However, we do not find any transiting planetary companions in the habitable zone of our target white dwarfs. Given the probability of eclipses of 1 per cent and our observing window from the ground, the non-detection of such companions in this first field is not surprising. Minute cadence DECam observations of additional fields will provide stringent constraints on the frequency of planets in the white dwarf habitable zone.
2289. White dwarf candidates in SDSS DR10
ID:
ivo://CDS.VizieR/J/MNRAS/448/2260
Title:
White dwarf candidates in SDSS DR10
Short Name:
J/MNRAS/448/2260
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a method which uses cuts in colour-colour and reduced proper motion-colour space to select white dwarfs without the recourse to spectroscopy while allowing an adjustable compromise between completeness and efficiency. Rather than just producing a list of white dwarf candidates, our method calculates a probability of being a white dwarf (P_WD_) for any object with available multiband photometry and proper motion. We applied this method to all objects in the Sloan Digital Sky Survey (SDSS) Data Release 10 (DR10) photometric footprint and to a few selected sources in DR7 which did not have reliable photometry in DR9 or DR10. This application results in a sample of 61 969 DR10 and 3799 DR7 photometric sources with calculated P_WD_ from which it is possible to select a sample of ~23000 high-fidelity white dwarf candidates with T_eff_>~7000K and g<=19. This sample contains over 14000 high confidence white dwarfs candidates which have not yet received spectroscopic follow-up. These numbers show that, to date, the spectroscopic coverage of white dwarfs in the SDSS photometric footprint is, on average, only ~40 percent complete. While we describe here in detail the application of our selection to the SDSS catalogue, the same method could easily be applied to other multicolour, large area surveys. We also publish a list of 8701 bright (g<=19) white dwarfs with SDSS spectroscopy, of which 1781 are new identifications in DR9/DR10.
2290. White dwarf candidates using LAMOST DR3
ID:
ivo://CDS.VizieR/J/MNRAS/452/765
Title:
White dwarf candidates using LAMOST DR3
Short Name:
J/MNRAS/452/765
Date:
21 Oct 2021
Publisher:
CDS
Description:
In previous work by Gentile Fusillo et al., we developed a selection method for white dwarf candidates which makes use of photometry, colours and proper motions to calculate a probability of being a white dwarf (P_WD_). The application of our method to the Sloan Digital Sky Survey (SDSS) data release 10 resulted in =~ 66000 photometrically selected objects with a derived P_WD_, approximately =~21000 of which are high-confidence white dwarf candidates. Here, we present an independent test of our selection method based on a sample of spectroscopically confirmed white dwarfs from the Large Sky Area Multi-Fiber Spectroscopic Telescope (LAMOST) survey. We do this by cross-matching all our =~66000 SDSS photometric white dwarf candidates with the over 4 million spectra available in the third data release of LAMOST. This results in 1673 white dwarf candidates with no previous SDSS spectroscopy, but with available LAMOST spectra. Among these objects, we identify 309 genuine white dwarfs. We find that our P_WD_ can efficiently discriminate between confirmed LAMOST white dwarfs and contaminants. Our white dwarf candidate selection method can be applied to any multiband photometric survey and in this work we conclusively confirm its reliability in selecting white dwarfs without recourse to spectroscopy. We also discuss the spectroscopic completeness of white dwarfs in LAMOST, as well as deriving effective temperatures, surface gravities and masses for the hydrogen-rich atmosphere white dwarfs in the newly identified LAMOST sample.

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