- 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.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/135/2177
- Title:
- High proper motion stars in the DSS. IV.
- Short Name:
- J/AJ/135/2177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Completion of the SUPERBLINK proper motion survey in the southern celestial hemisphere has turned up 170 new stars with proper motion 0.45"/yr<mu<2.0"/yr. This fourth and final installment completes the all-sky, data mining of the Digitized Sky Surveys for stars with large proper motions. The areas investigated in this final installment comprise 11600deg^-2^ in the declination (DE) range -30{deg}<DE<0{deg} and in low Galactic latitude areas south of DE=-30{deg} which had not been covered in earlier data releases. Astrometric and photometric data are provided for the 170 new stars, along with finder charts. Most of the new discoveries are found in densely populated fields along the Milky Way, toward the Galactic bulge/center. The list of new discoveries includes four stars with proper motion mu>1.0"/yr. The total list of high proper motion stars recovered by SUPERBLINK in the southern sky now includes 2228 stars with proper motions 0.45"/yr<mu<2.0"/yr.
- ID:
- ivo://CDS.VizieR/J/ApJ/734/68
- Title:
- High redshift galaxy clusters in deep fields
- Short Name:
- J/ApJ/734/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Identification of high-redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada-France-Hawaii Telescope (CFHT) wide field, 202 clusters from the CFHT deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) field, and 737 clusters from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) field. The redshifts of these clusters are in the range 0.1<~z<~1.6. Merging these cluster samples gives 1644 clusters in the four survey fields, of which 1088 are newly identified and more than half are from the large SWIRE field. Among 228 clusters of z>=1, 191 clusters are newly identified, and most of them from the SWIRE field. With this large sample of high-redshift clusters, we study the color evolution of the brightest cluster galaxies (BCGs).
- ID:
- ivo://CDS.VizieR/J/ApJ/725/394
- Title:
- High-redshift Ly{alpha} emitters
- Short Name:
- J/ApJ/725/394
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an atlas of 88 z~5.7 and 30 z~6.5 Ly{alpha} emitters obtained from a wide-field narrowband survey. We combined deep narrowband imaging in 120{AA} bandpass filters centered at 8150{AA} and 9140{AA} with deep BVRIz broadband imaging to select high-redshift galaxy candidates over an area of 4180arcmin^2^. The goal was to obtain a uniform selection of comparable depth over the seven targeted fields in the two filters. For the GOODS-North region of the Hubble Deep Field-North field, we also selected candidates using a 120{AA} filter centered at 9210{AA}. We made spectroscopic observations with Keck DEIMOS of nearly all the candidates to obtain the final sample of Ly{alpha} emitters. At the 3.3{AA} resolution of the DEIMOS observations the asymmetric profile for Ly{alpha} emission can be clearly seen in the spectra of nearly all the galaxies. We show that the spectral profiles are surprisingly similar for many of the galaxies and that the composite spectral profiles are nearly identical at z=5.7 and z=6.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/8
- Title:
- High-redshift QSOs in the COSMOS survey
- Short Name:
- J/ApJ/693/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new measurement of the space density of high-redshift (z~3.0-4.5), X-ray-selected quasi-stellar objects (QSOs) obtained by exploiting the deep and uniform multiwavelength coverage of the COSMOS survey. We have assembled a large (40 objects), homogeneous sample of z>3 QSOs with X-ray flux F0.5-2keV>10^-15^erg/cm^2^/s, and available spectroscopic (22) or photometric (18) redshifts. We discuss their optical (color-color diagrams) and X-ray properties, their number counts and space densities and compare our findings with previous works and model predictions.
- ID:
- ivo://CDS.VizieR/J/AJ/121/31
- Title:
- High-redshift quasars in SDSS
- Short Name:
- J/AJ/121/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third paper in a series aimed at finding high-redshift quasars from five-color (u'g'r'i'z') imaging data taken along the celestial equator by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. In this paper, we first present the observations of 14 bright, high-redshift quasars (3.66<=z<=4.77, i*<~20) discovered in the SDSS fall equatorial stripe, and the SDSS photometry of two previously known high-redshift quasars in the same region of the sky. Combined with the quasars presented in Paper I (1999AJ....118....1F) and by Schneider et al. (2001AJ....121.1232S), we define a color-selected flux-limited sample of 39 quasars at 3.6<z<5.0 and i*<~20, covering a total effective area of 182deg^2^. From this sample, we estimate the average spectral power-law slope in the rest-frame UV for quasars at z~4 to be -0.79 with a standard deviation of 0.34, and the average rest-frame equivalent width of the Ly{alpha}+N V emission line to be 69{AA} with a standard deviation of 18{AA}. Based on observations obtained with the Sloan Digital Sky Survey, with the Apache Point Observatory 3.5m telescope.
