- ID:
- ivo://CDS.VizieR/J/ApJS/98/659
- Title:
- Galactic PNe statistical distance scale
- Short Name:
- J/ApJS/98/659
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A statistical distance scale is proposed. It is based on the correlation between the ionized mass and the radius and the correlation between the radio continuum surface brightness temperature and the nebular radius. The proposed statistical distance scale is an average of the two distances obtained using the correlations. These correlations, calibrated on the 132 planetary nebulae with well-determined individual distances by Zhang, can reproduce not only the average distance of a sample of Galactic Bulge planetary nebulae exactly at the distance to the Galactic center, but also the expected gaussian distribution of their distances around the Galactic center. This new distance scale is applied to 647 Galactic planetary nebulae. It is estimated that this distance scale can be accurate on average to 35%-50%. Our statistical distance scale is in good agreement with the one recently proposed by Van de Steene and Zijlstra
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/1673
- Title:
- Galactic post-AGB stars distances
- Short Name:
- J/MNRAS/447/1673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have commenced a detailed analysis of the known sample of Galactic post-asymptotic giant branch (PAGB) objects compiled in the Torun catalogue of Szczerba et al. (2007A&A...469..799S, Cat. J/A+A/469/799), and present, for the first time, homogeneously derived distance determinations for the 209 likely and 87 possible catalogued PAGB stars from that compilation. Knowing distances are essential in determining meaningful physical characteristics for these sources and this has been difficult to determine for most objects previously. The distances were determined by modelling their spectral energy distributions (SEDs) with multiple blackbody curves, and integrating under the overall fit to determine the total distance-dependent flux. This approach was undertaken for consistency as precise spectral types, needed for more detailed fitting, were unknown in the majority of cases. The SED method works because the luminosity of these central stars is very nearly constant from the tip of the AGB phase to the beginning of the white dwarf cooling track. This then enables us to use a standard-candle luminosity to estimate the SED distances. For Galactic thin-disc PAGB objects, we use three luminosity bins based on typical observational characteristics, ranging between 3500 and 12000L_{sun}_. We further adopt a default luminosity of 4000L_{sun}_ for bulge objects and 1700L_{sun}_ for the thick-disc and halo objects. We have also applied the above technique to a further sample of 54 related nebulae not in the current edition of the Torun catalogue. In a follow-up paper, we will estimate distances to the subset of RV Tauri variables using empirical period-luminosity relations, and to the R CrB stars, allowing a population comparison of these objects with the other subclasses of PAGB stars for the first time.
- ID:
- ivo://CDS.VizieR/J/PASP/124/128
- Title:
- Galactic structure toward the Carina tangent
- Short Name:
- J/PASP/124/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This investigation presents a photometric study of the Galactic structure toward the Carina arm tangent. The field is located between 280{deg} and 286{deg} Galactic longitude and -4{deg} to 4{deg} Galactic latitude. All currently available uvby{beta} data are used to obtain homogeneous color excesses and distances for more than 260 stars of spectral types O to G. We present revised distances and average extinction for the open clusters and cluster candidates NGC 3293, NGC 3114, Loden 46, and Loden 112.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/3203
- Title:
- GALAH observational overview
- Short Name:
- J/MNRAS/465/3203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Galactic Archaeology with HERMES (GALAH) Survey is a massive observational project to trace the Milky Way's history of star formation, chemical enrichment, stellar migration and minor mergers. Using high-resolution (R~28,000) spectra taken with the High Efficiency and Resolution Multi-Element Spectrograph (HERMES) instrument at the Anglo-Australian Telescope (AAT), GALAH will determine stellar parameters and abundances of up to 29 elements for up to one million stars. Selecting targets from a colour-unbiased catalogue built from 2MASS, APASS and UCAC4 data, we expect to observe dwarfs at 0.3 to 3kpc and giants at 1 to 10kpc. This enables a thorough local chemical inventory of the Galactic thin and thick disks, and also captures smaller samples of the bulge and halo. In this paper we present the plan, process and progress as of early 2016 for GALAH survey observations. In our first two years of survey observing we have accumulated the largest high-quality spectroscopic data set at this resolution, over 200,000 stars. We also present the first public GALAH data catalogue: stellar parameters (Teff, log(g), [Fe/H], [alpha/Fe]), radial velocity, distance modulus and reddening for 10680 observations of 9860 Tycho-2 stars that may be included in the first Gaia data release.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/15
- Title:
- Galaxy distances with the Fundamental Manifold
- Short Name:
- J/ApJ/748/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We demonstrate how the Fundamental Manifold (FM) can be used to cross-calibrate distance estimators even when those "standard candles" are not found in the same galaxy. Such an approach greatly increases the number of distance measurements that can be utilized to check for systematic distance errors and the types of estimators that can be compared. Here we compare distances obtained using Type Ia supernova (SN Ia), Cepheids, surface brightness fluctuations, the luminosity of the tip of the red giant branch, circumnuclear masers, eclipsing binaries, RR Lyrae stars, and the planetary nebulae luminosity functions. We find no significant discrepancies (differences are <2{sigma}) between distance methods, although differences at the ~10% level cannot yet be ruled out. The potential exists for significant refinement because the data used here are heterogeneous B-band magnitudes that will soon be supplanted by homogeneous, near-infrared magnitudes. We illustrate the use of FM distances to (1) revisit the question of the metallicity sensitivity of various estimators, confirming the dependence of SN Ia distances on host galaxy metallicity, and (2) provide an alternative calibration of H_0_ that replaces the classical ladder approach in the use of extragalactic distance estimators with one that utilizes data over a wide range of distances simultaneously.
- ID:
- ivo://CDS.VizieR/V/117A
- Title:
- Geneva-Copenhagen Survey of Solar neighbourhood
- Short Name:
- V/117A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (from paper II, 2007) Ages, metallicities, space velocities, and Galactic orbits of stars in the Solar neighbourhood are fundamental observational constraints on models of galactic disk evolution. Understanding and minimising systematic errors and sample selection biases in the data is crucial for their interpretation. We aim to consolidate the calibrations of uvbyb photometry into T_eff_, [Fe/H], distance, and age for F and G stars and rediscuss the results of the Geneva-Copenhagen Survey (GCS, Nordstrom et al., 2004, paper I) in terms of the evolution of the disk. We use recent V-K photometry, angular diameters, high-resolution spectroscopy, Hipparcos parallaxes, and extensive numerical simulations to re-examine and verify the temperature, metallicity, distance, and reddening calibrations for the uvbyb system. We also highlight the selection effects inherent in the apparent-magnitude limited GCS sample. We substantially improve the T_eff_ and [Fe/H] calibrations for early F stars, where spectroscopic temperatures have large systematic errors. A slight offset of the GCS photometry and the non-standard helium abundance of the Hyades invalidate its use for checking metallicity or age scales; however, the distances, reddenings, metallicities, and age scale for GCS field stars require minor corrections only. Our recomputed ages are in excellent agreement with the independent determinations by Takeda et al. (2007ApJS..168..297T), indicating that isochrone ages can now be reliably determined. The revised G-dwarf metallicity distribution remains incompatible with closed-box models, and the age-metallicity relation for the thin disk remains almost flat, with large and real scatter at all ages sigma_intrinsic=0.20 dex). Dynamical heating of the thin disk continues throughout its life; specific in-plane dynamical effects dominate the evolution of the U and V velocities, while the W velocities remain random at all ages. When assigning thick and thin-disk membership for stars from kinematic criteria, parameters for the oldest stars should be used to characterise the thin disk.
- ID:
- ivo://CDS.VizieR/V/130
- Title:
- Geneva-Copenhagen Survey of Solar neighbourhood III
- Short Name:
- V/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ages, chemical compositions, velocity vectors, and Galactic orbits for stars in the solar neighbourhood are fundamental test data for models of Galactic evolution. The Geneva-Copenhagen Survey of the Solar neighbourhood (Nordstrom et al. 2004A&A...418..989N; GCS), a magnitude-complete, kinematically unbiased sample of 16,682 nearby F and G dwarfs, is the largest available sample with complete data for stars with ages spanning that of the disk. We aim to improve the accuracy of the GCS data by implementing the recent revision of the Hipparcos parallaxes. The new parallaxes yield improved astrometric distances for 12,506 stars in the GCS. We also use the parallaxes to verify the distance calibration for uvbyHbeta photometry by Holmberg et al. (2007A&A...475..519H; GCS II, Cat. VI/117). We add new selection criteria to exclude evolved cool stars giving unreliable results and derive distances for 3,580 stars with large parallax errors or not observed by Hipparcos. We also check the GCS II scales of T_eff_ and [Fe/H] and find no need for change. From the new distances we compute revised Mv, U, V, W, and Galactic orbital parameters for 13,520 GCS stars. We also recompute stellar ages with the new values of Mv from the Padova stellar evolution models used in GCS I-II, and compare them with ages from the Yale-Yonsei and Victoria-Regina models. Finally, we compare the observed age-velocity relation in W with three simulated disk heating scenarios to show the potential of the data. With these revisions, the basic data for the GCS stars should now be as reliable as is possible with existing techniques. Further improvement must await consolidation of the T_eff_ scale from angular diameters and fluxes, and the Gaia trigonometric parallaxes. We discuss the conditions for improving computed stellar ages from new input data, and for distinguishing different disk heating scenarios from data sets of the size and precision of the GCS.
- ID:
- ivo://CDS.VizieR/J/ApJ/845/44
- Title:
- 340GHz SMA obs. of 50 nearby protoplanetary disks
- Short Name:
- J/ApJ/845/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey at subarcsecond resolution of the 340GHz dust continuum emission from 50 nearby protoplanetary disks, based on new and archival observations with the Submillimeter Array. The observed visibility data were modeled with a simple prescription for the radial surface brightness profile. The results were used to extract intuitive, empirical estimates of the emission "size" for each disk, R_eff_, defined as the radius that encircles a fixed fraction of the total continuum luminosity, L_mm_. We find a significant correlation between the sizes and luminosities, such that R_eff_{propto}L_mm_^0.5^, providing a confirmation and quantitative characterization of a putative trend that was noted previously. This correlation suggests that these disks have roughly the same average surface brightness interior to their given effective radius, ~0.2Jy/arcsec^2^ (or 8K in brightness temperature). The same trend remains, but the 0.2dex of dispersion perpendicular to this relation essentially disappears, when we account for the irradiation environment of each disk with a crude approximation of the dust temperatures based on the stellar host luminosities. We consider two (not mutually exclusive) explanations for the origin of this size-luminosity relationship. Simple models of the growth and migration of disk solids can account for the observed trend for a reasonable range of initial conditions, but only on timescales that are much shorter than the nominal ages present in the sample. An alternative scenario invokes optically thick emission concentrated on unresolved scales, with filling factors of a few tens of percent, which is perhaps a manifestation of localized particle traps.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/33
- Title:
- GOBELINS. IV. VLBA obs. of Taurus
- Short Name:
- J/ApJ/859/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new trigonometric parallaxes and proper motions of young stellar objects in the Taurus molecular cloud complex from observations collected with the Very Long Baseline Array as part of the Gould's Belt Distances Survey. We detected 26 young stellar objects and derived trigonometric parallaxes for 18 stars with an accuracy of 0.3% to a few percent. We modeled the orbits of six binaries and determined the dynamical masses of the individual components in four of these systems (V1023 Tau, T Tau S, V807 Tau, and V1000 Tau). Our results are consistent with the first trigonometric parallaxes delivered by the Gaia satellite and reveal the existence of significant depth effects. We find that the central portion of the dark cloud Lynds 1495 is located at d=129.5+/-0.3pc, while the B216 clump in the filamentary structure connected to it is at d=158.1+/-1.2pc. The closest and remotest stars in our sample are located at d=126.6+/-1.7pc and d=162.7+/-0.8pc, yielding a distance difference of about 36pc. We also provide a new distance estimate for HL Tau that was recently imaged. Finally, we compute the spatial velocity of the stars with published radial velocity and investigate the kinematic properties of the various clouds and gas structures in this region.
- ID:
- ivo://CDS.VizieR/J/ApJ/834/142
- Title:
- Gould's Belt Distances Survey (GOBELINS). II. OMC
- Short Name:
- J/ApJ/834/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the Gould's Belt Distances Survey of young star-forming regions toward the Orion Molecular Cloud Complex. We detected 36 young stellar objects (YSOs) with the Very Large Baseline Array, 27 of which have been observed in at least three epochs over the course of two years. At least half of these YSOs belong to multiple systems. We obtained parallax and proper motions toward these stars to study the structure and kinematics of the Complex. We measured a distance of 388+/-5pc toward the Orion Nebula Cluster, 428+/-10pc toward the southern portion L1641, 388+/-10pc toward NGC 2068, and roughly ~420pc toward NGC 2024. Finally, we observed a strong degree of plasma radio scattering toward {lambda} Ori.
