- ID:
- ivo://CDS.VizieR/J/MNRAS/471/100
- Title:
- Hi-GAL compact source catalog. -71.0<l<67.0
- Short Name:
- J/MNRAS/471/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschelin five infrared continuum bands between 70 and 500{mu}m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane -71.0{deg}<l<67.0{deg}. The band-merged catalogue contains 100 922 sources with a regular SED, 24584 of which show a 70-{mu}m counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between 'on-arm' and 'interarm' positions.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/591/A149
- Title:
- Hi-GAL. inner Milky Way: +68>=l>=70
- Short Name:
- J/A+A/591/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500{mu}m, encompassing the peak of the spectral energy distribution of cold dust for 8<~T<~50K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68{deg}>~l>~-70{deg} in a |b|<=1{deg} latitude strip. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2{deg}x2{deg} "tile" that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Hi-GAL DR1 images are cirrus noise limited and reach the 1{sigma}-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60"/s scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 120581, 291858, 280143, 161946, and 85811 compact sources in the five bands.
- ID:
- ivo://CDS.VizieR/J/A+A/470/787
- Title:
- High energy peaked BL Lacs optical spectros.
- Short Name:
- J/A+A/470/787
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The multi-frequency sedentary survey is a flux-limited, statistically well-defined sample of highly X-ray dominated (i.e., with a very high X-ray to radio flux ratio) BL Lacertae objects, which includes 150 sources. In this paper, the third of the series, we report the results of a dedicated optical spectroscopy campaign that, together with results from other independent optical follow-up programs, led to the spectroscopic identification of all sources in the sample. We carried out a systematic spectroscopic campaign for the observation of all unidentified objects of the sample using the ESO 3.6m, the KPNO 4m, and the TNG optical telescopes.
- ID:
- ivo://CDS.VizieR/J/ApJ/300/779
- Title:
- High-latitude H-alpha emission stars
- Short Name:
- J/ApJ/300/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Approximately 1300 5.2x5.2deg^2^ red-sensitive objective prism plates have been searched for H{alpha}-emission stars in order to complete the search of the entire sky. The survey here reported represents 59% of the whole sky, defined by the region north of declination -25{deg} and mostly further than 10{deg} from the Galactic plane; the omitted portions had already been surveyed, in part at Warner and Swasey, in part elsewhere. Two hundred and six stars have been newly found, mostly of unknown spectral type. The stars' latitude distribution suggest that they are mainly moderately high luminosity disk population stars. There are new finds especially in Orion and the Taurus dark clouds (limiting mag ~13).
- ID:
- ivo://CDS.VizieR/J/A+A/620/A118
- Title:
- Highly Accreting Quasars: SDSS Low z Catalog
- Short Name:
- J/A+A/620/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The most highly accreting quasars are of special interest in studies of the physics of active galactic nuclei (AGNs) and host galaxy evolution. Quasars accreting at high rates (L/LEdd~1) hold promise for use as "standard candles": distance indicators detectable at very high redshift. However, their observational properties are still largely unknown. We seek to identify a significant number of extreme accretors. A large sample can clarify the main properties of quasars radiating near L/LEdd~1 (in this paper they are designated as extreme Population A quasars or simply as extreme accretors) in the H{beta} spectral range for redshift <~0.8. We use selection criteria derived from four-dimensional Eigenvector 1 (4DE1) studies to identify and analyze spectra for a sample of 334 candidate sources identified from the SDSS DR7 database. The source spectra were chosen to show a ratio R_FeII_ between the FeII emission blend at {lambda}4570 and H{beta}, R_FeII_ > 1. Composite spectra were analyzed for systematic trends as a function of FeII strength, line width, and [OIII] strength. We introduced tighter constraints on the signal-to-noise ratio (S/N) and R_FeII_ values that allowed us to isolate sources most likely to be extreme accretors. We provide a database of detailed measurements. Analysis of the data allows us to confirm that H{beta} shows a Lorentzian function with a full width at half maximum (FWHM) of H{beta}<=4000km/s. We find no evidence for a discontinuity at 2000km/s in the 4DE1, which could mean that the sources below this FWHM value do not belong to a different AGN class. Systematic [OIII] blue shifts, as well as a blueshifted component in H{beta} are revealed. We interpret the blueshifts as related to the signature of outflowing gas from the quasar central engine. The FWHM of H{beta} is still affected by the blueshifted emission; however, the effect is non-negligible if the FWHM H{beta} is used as a "virial broadening estimator" (VBE). We emphasize a strong effect of the viewing angle on H{beta} broadening, deriving a correction for those sources that shows major disagreement between virial and concordance cosmology luminosity values. The relatively large scatter between concordance cosmology and virial luminosity estimates can be reduced (by an order of magnitude) if a correction for orientation effects is included in the FWHM H{beta} value; outflow and sample definition yield relatively minor effects.
- ID:
- ivo://CDS.VizieR/J/ApJ/815/130
- Title:
- High-mass molecular clumps from MALT90
- Short Name:
- J/ApJ/815/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present dust column densities and dust temperatures for ~3000 young, high-mass molecular clumps from the Millimeter Astronomy Legacy Team 90GHz survey, derived from adjusting single-temperature dust emission models to the far-infrared intensity maps measured between 160 and 870{mu}m from the Herschel/Herschel Infrared Galactic Plane Survey (Hi-Gal) and APEX/APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) surveys. We discuss the methodology employed in analyzing the data, calculating physical parameters, and estimating their uncertainties. The population average dust temperature of the clumps are 16.8+/-0.2K for the clumps that do not exhibit mid-infrared signatures of star formation (quiescent clumps), 18.6+/-0.2K for the clumps that display mid-infrared signatures of ongoing star formation but have not yet developed an HII region (protostellar clumps), and 23.7+/-0.2 and 28.1+/-0.3K for clumps associated with HII and photo-dissociation regions, respectively. These four groups exhibit large overlaps in their temperature distributions, with dispersions ranging between 4 and 6K. The median of the peak column densities of the protostellar clump population is 0.20+/-0.02g/cm2, which is about 50% higher compared to the median of the peak column densities associated with clumps in the other evolutionary stages. We compare the dust temperatures and column densities measured toward the center of the clumps with the mean values of each clump. We find that in the quiescent clumps, the dust temperature increases toward the outer regions and that these clumps are associated with the shallowest column density profiles. In contrast, molecular clumps in the protostellar or HII region phase have dust temperature gradients more consistent with internal heating and are associated with steeper column density profiles compared with the quiescent clumps.
- ID:
- ivo://CDS.VizieR/J/ApJS/231/11
- Title:
- High-mass starless clump candidates from ATLASGAL
- Short Name:
- J/ApJS/231/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a sample of 463 high-mass starless clump (HMSC) candidates within -60{deg}<l<60{deg} and -1{deg}<b<1{deg}. This sample has been singled out from 10861 ATLASGAL clumps. None of these sources are associated with any known star-forming activities collected in SIMBAD and young stellar objects identified using color-based criteria. We also make sure that the HMSC candidates have neither point sources at 24 and 70{mu}m nor strong extended emission at 24{mu}m. Most of the identified HMSCs are infrared dark, and some are even dark at 70{mu}m. Their distribution shows crowding in Galactic spiral arms and toward the Galactic center and some well-known star-forming complexes. Many HMSCs are associated with large-scale filaments. Some basic parameters were attained from column density and dust temperature maps constructed via fitting far-infrared and submillimeter continuum data to modified blackbodies. The HMSC candidates have sizes, masses, and densities similar to clumps associated with Class II methanol masers and H II regions, suggesting that they will evolve into star-forming clumps. More than 90% of the HMSC candidates have densities above some proposed thresholds for forming high-mass stars. With dust temperatures and luminosity-to-mass ratios significantly lower than that for star-forming sources, the HMSC candidates are externally heated and genuinely at very early stages of high-mass star formation. Twenty sources with equivalent radii r_eq_<0.15pc and mass surface densities {Sigma}>0.08g/cm^2^ could be possible high-mass starless cores. Further investigations toward these HMSCs would undoubtedly shed light on comprehensively understanding the birth of high-mass stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/719/1293
- Title:
- High precision orbits of 5 SB2 stars
- Short Name:
- J/ApJ/719/1293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision radial velocities (RVs) of double-lined spectroscopic binary stars HD78418, HD123999, HD160922, HD200077, and HD210027. They were obtained based on the high-resolution echelle spectra collected with the Keck I/HIRES, Shane/CAT/Hamspec, and TNG/Sarge telescopes/spectrographs over the years 2003-2008 as part of the TATOOINE search for circumbinary planets. The RVs were computed using our novel iodine cell technique for double-line binary stars, which relies on tomographically disentangled spectra of the components of the binaries. The precision of the RVs is of the order of 1-10m/s, and to properly model such measurements one needs to account for the light-time effect within the binary's orbit, relativistic effects, and RV variations due to tidal distortions of the components of the binaries. With such proper modeling, our RVs combined with the archival visibility measurements from the Palomar Testbed Interferometer (PTI) allow us to derive very precise spectroscopic/astrometric orbital and physical parameters of the binaries.
- ID:
- ivo://CDS.VizieR/J/ApJ/562/337
- Title:
- High proper-motion stars from MACHO astrometry
- Short Name:
- J/ApJ/562/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the preliminary results of our astrometric study of stellar motions along the lines of sight of the Magellanic Clouds and the Galactic bulge. Using 5 years of MACHO project point-spread function photometry, we find that we can easily select stars with proper motions of 0.03"/yr from these very dense fields, using the characteristic shapes of their light curves. By performing astrometry on photometrically selected, candidate, high proper motion (HPM) stars in 50 deg^2^, we have discovered 154 new HPM stars from ~55 million stars monitored by the MACHO project. These new objects have proper motions as high as 0.5"/yr, brightnesses ranging from V ~13 to V~19, and V-R colors between 0.3 and 1.45.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1247
- Title:
- High proper motion stars in the DSS. III
- Short Name:
- J/AJ/130/1247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 182 southern stars with proper motion larger than 0.45"/yr. The stars were found in an expansion of the SUPERBLINK proper-motion survey to 8980{deg}^2^ south of DE=-30{deg}. The new high proper motion stars include 123 objects with {mu}>0.5"/yr and 5 with{mu}>1.0"/yr.
