- ID:
- ivo://CDS.VizieR/J/AJ/111/370
- Title:
- Orbits of 37 close visual systems
- Short Name:
- J/AJ/111/370
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New orbital elements are presented for 37 close visual systems that have been observed and in some cases discovered by speckle interferometry. Periods of these systems range from 5.7 to 425yr, semimajor axes from 0.06" to 1.1". Four of these systems (Kui 18, Fin 325, StF 2597, and McA 77) had no previously published orbital analyses, while elements for a number of other systems have undergone major revisions. Finally, 135 new or revised interferometric measurements of these systems are also presented, as well as 8 negative results.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/152/11
- Title:
- Orbits of four triple stars
- Short Name:
- J/AJ/152/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Each of the nearby triple systems HIP 7601, 13498, 23824, and 113597 (HD 10800, 18198, 35877, 217379) consist of solar-type dwarfs with comparable masses, where all three components are resolved spectrally, while the outer pairs are resolved both visually and spectrally. These stars are relatively young (between 100 and 600Myr) and chromospherically active (X-ray sources), although they rotate slowly. I determine the spectroscopic orbits of the inner subsystems (periods 19.4, 14.1, 5.6, 20.3days) and the orbits of the outer systems (periods 1.75, 51, 27, 500years, respectively). For HIP 7601 and 13498, the combined spectro-interferometric outer orbits produce direct measurement of the masses of all of the components, allowing for a comparison with stellar models. The 6708{AA} lithium line is present and its strength is measured in each component individually by subtracting the contributions of the other components. The inner and outer orbits of HIP 7601 are nearly circular, likely co-planar, and have a modest period ratio of 1:33. This study contributes to the characterization of hierarchical multiplicity in the solar neighborhood and provides data for testing stellar evolutionary models and chronology.
- ID:
- ivo://CDS.VizieR/J/ApJ/804/114
- Title:
- Parameter-estimation performance with LIGO
- Short Name:
- J/ApJ/804/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Advanced ground-based gravitational-wave (GW) detectors begin operation imminently. Their intended goal is not only to make the first direct detection of GWs, but also to make inferences about the source systems. Binary neutron-star mergers are among the most promising sources. We investigate the performance of the parameter-estimation (PE) pipeline that will be used during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) in 2015: we concentrate on the ability to reconstruct the source location on the sky, but also consider the ability to measure masses and the distance. Accurate, rapid sky localization is necessary to alert electromagnetic (EM) observatories so that they can perform follow-up searches for counterpart transient events. We consider PE accuracy in the presence of non-stationary, non-Gaussian noise. We find that the character of the noise makes negligible difference to the PE performance at a given signal-to-noise ratio. The source luminosity distance can only be poorly constrained, since the median 90% (50%) credible interval scaled with respect to the true distance is 0.85 (0.38). However, the chirp mass is well measured. Our chirp-mass estimates are subject to systematic error because we used gravitational-waveform templates without component spin to carry out inference on signals with moderate spins, but the total error is typically less than 10^-3^M_{sun}_. The median 90% (50%) credible region for sky localization is ~600deg^2^ (~150deg^2^), with 3% (30%) of detected events localized within 100deg^2^. Early aLIGO, with only two detectors, will have a sky-localization accuracy for binary neutron stars of hundreds of square degrees; this makes EM follow-up challenging, but not impossible.
- ID:
- ivo://CDS.VizieR/J/ApJ/899/55
- Title:
- Parameters of protoplanetary disks in 5 SFRs
- Short Name:
- J/ApJ/899/55
- Date:
- 14 Mar 2022 07:11:43
- Publisher:
- CDS
- Description:
- Spatial correlations among protoplanetary disk orientations carry unique information on physics of multiple-star formation processes. We select five nearby star-forming regions that comprise a number of protoplanetary disks with spatially resolved images with ALMA and Hubble Space Telescope, and we search for the mutual alignment of the disk axes. Specifically, we apply the Kuiper test to examine the statistical uniformity of the position angle (PA: the angle of the major axis of the projected disk ellipse measured counterclockwise from the north) distribution. The disks located in the star-forming regions, except the Lupus clouds, do not show any signature of the alignment, supporting the random orientation. Rotational axes of 16 disks with spectroscopic measurement of PA in the LupusIII cloud, a subregion of the Lupus field, however, exhibit a weak and possible departure from the random distribution at a 2{sigma} level, and the inclination angles of the 16 disks are not uniform as well. Furthermore, the mean direction of the disk PAs in the LupusIII cloud is parallel to the direction of its filament structure and approximately perpendicular to the magnetic field direction. We also confirm the robustness of the estimated PAs in the Lupus clouds by comparing the different observations and estimators based on three different methods, including sparse modeling. The absence of the significant alignment of the disk orientation is consistent with the turbulent origin of the disk angular momentum. Further observations are required to confirm/falsify the possible disk alignment in the Lupus III cloud.
- ID:
- ivo://CDS.VizieR/J/other/PASAu/10.310
- Title:
- Parkes-Tidbinbilla radio sources
- Short Name:
- J/other/PASAu/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the 2.3GHz total and correlated flux densities on a baseline of 275km of all sources in the Parkes catalogue which : (i) are south of declination +10deg, (ii) have a catalogued 2.7GHz total flux density exceeding 0.5Jy, and (iii) have a 2.7/5.0GHz spectral index flatter than -0.5. More than 14% of the sample showed visibility amplitudes greater than 0.9, and more than 72% showed visibility amplitudes greater than 0.5. Of the sources with optical or other identifications 79% were quasars. In this paper we briefly summarise the results of this survey.
- ID:
- ivo://CDS.VizieR/J/AJ/139/2269
- Title:
- P Cyg H{alpha} squared visibility
- Short Name:
- J/AJ/139/2269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High spatial resolution observations of the H{alpha}-emitting wind structure associated with the luminous blue variable star P Cygni were obtained with the Navy Prototype Optical Interferometer. These observations represent the most comprehensive interferometric data set on P Cyg to date. We demonstrate how the apparent size of the H{alpha}-emitting region of the wind structure of P Cyg compares between the 2005, 2007, and 2008 observing seasons and how this relates to the H{alpha} line spectroscopy. Using the data sets from 2005, 2007, and 2008 observing seasons, we fit a circularly symmetric Gaussian model to the interferometric signature from the H#-emitting wind structure of P Cyg.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1623
- Title:
- PHASES diff. astrometry data archive. II.
- Short Name:
- J/AJ/140/1623
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture measurements covering a much longer timespan (from eyepiece measurements, speckle interferometry, and adaptive optics) to determine improved visual orbits for 20 binary stars. In some cases, radial velocity observations exist to constrain the full three-dimensional orbit and determine component masses. The visual orbit of one of these binaries - {alpha} Com (HD 114378) - shows that the system is likely to have eclipses, despite its very long period of 26 years. The next eclipse is predicted to be within a week of 2015 January 24.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1657
- Title:
- PHASES diff. astrometry data archive. V.
- Short Name:
- J/AJ/140/1657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Palomar High-precision Astrometric Search for Exoplanet Systems monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Six binaries are presented that show evidence of substellar companions orbiting either the primary or secondary star. Of these six systems, the likelihoods of two of the detected perturbations to represent real objects are considered to be "high confidence," while the remaining four systems are less certain and will require continued observations for confirmation.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1579
- Title:
- PHASES differential astrometry data archive
- Short Name:
- J/AJ/140/1579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) monitored 51 subarcsecond binary systems to determine precision binary orbits, study the geometries of triple and quadruple star systems, and discover previously unknown faint astrometric companions as small as giant planets. PHASES measurements made with the Palomar Testbed Interferometer (PTI) from 2002 until PTI ceased normal operations in late 2008 are presented. Infrared differential photometry of several PHASES targets were measured with Keck Adaptive Optics and are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/74
- Title:
- PHIBSS: CO observations of star-forming galaxies
- Short Name:
- J/ApJ/768/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present PHIBSS, the IRAM Plateau de Bure high-z blue sequence CO(3-2) survey of the molecular gas properties in massive, main-sequence star-forming galaxies (SFGs) near the cosmic star formation peak. PHIBSS provides 52 CO detections in two redshift slices at z~1.2 and 2.2, with log(M_*_(M_{sun}_))>=10.4 and log(SFR(M_{sun}_/yr))>=1.5. Including a correction for the incomplete coverage of the M_*_-SFR plane, and adopting a "Galactic" value for the CO-H_2_ conversion factor, we infer average gas fractions of ~0.33 at z~1.2 and ~0.47 at z~2.2. Gas fractions drop with stellar mass, in agreement with cosmological simulations including strong star formation feedback. Most of the z~1-3 SFGs are rotationally supported turbulent disks. The sizes of CO and UV/optical emission are comparable. The molecular-gas-star-formation relation for the z=1-3 SFGs is near-linear, with a ~0.7Gyr gas depletion timescale; changes in depletion time are only a secondary effect. Since this timescale is much less than the Hubble time in all SFGs between z~0 and 2, fresh gas must be supplied with a fairly high duty cycle over several billion years. At given z and M_*_, gas fractions correlate strongly with the specific star formation rate (sSFR). The variation of sSFR between z~0 and 3 is mainly controlled by the fraction of baryonic mass that resides in cold gas.
