- ID:
- ivo://CDS.VizieR/J/ApJ/689/194
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/ApJ/689/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic planetary nebula (PN) distances are derived, except in a small number of cases, through the calibration of statistical properties of PNs. Such calibrations are limited by the accuracy of individual PN distances, which are obtained with several nonhomogeneous methods, each carrying its own set of liabilities. In this paper we use the physical properties of the PNs in the Magellanic Clouds and their accurately known distances to recalibrate the Shklovsky/Daub (1982ApJ...260..612D) distance technique. Our new calibration is very similar (within 1%) to the commonly used distance scale by Cahn et al. (1992, Cat. J/A+AS/94/399), although there are important differences. We present a catalog of Galactic PN distances using our recalibration, which can be used for future applications, and compare the best individual Galactic PN distances to our new and several other distance scales, both in the literature and newly recalibrated by us, finding that our scale is the most reliable to date.
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- ID:
- ivo://CDS.VizieR/J/AJ/115/1989
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/AJ/115/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is well known that the IRAS colors of planetary nebulae (PNe) are very similar to blackbody colors. Taking account of this characteristic, we define a new method to obtain some information about the distance to PNe by blackbody fitting of IRAS four-band fluxes, assuming these fluxes are due to thermal emission from the nebular dust envelope. The fit should have two free parameters - the dust temperature TD and the distance-dependent "scaling factor" A - under the assumption of uniform dust mass. We find that the A-values have a good correlation with published distances. The scaling factor A could be a more effective distance scale than others, because many PNe have been detected as IRAS sources and the extinction of IRAS fluxes is not so severe, and is known. We also find that TD is concentrated between 100 and 200K, with a typical value of about 150K.
- ID:
- ivo://CDS.VizieR/J/other/A+ARV/15.289
- Title:
- Distances of local galaxies
- Short Name:
- J/other/A+ARV/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Any calibration of the present value of the Hubble constant (H_0_) requires recession velocities and distances of galaxies. While the conversion of observed velocities into true recession velocities has only a small effect on the result, the derivation of unbiased distances which rest on a solid zero point and cover a useful range of about 4-30Mpc is crucial. A list of 279 such galaxy distances within v<2000km/s is given which are derived from the tip of the red-giant branch (TRGB), from Cepheids, and/or from supernovae of type Ia (SNe Ia).
- ID:
- ivo://CDS.VizieR/J/A+A/446/515
- Title:
- Distances of nearby ultracool dwarfs
- Short Name:
- J/A+A/446/515
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present updated results of spectroscopic follow-up observations of a sample of 45 M dwarf candidates identified by Phan-Bao et al. (2003, Cat. <J/A+A/401/959>) based on the DENIS photometry and proper motion measurements. Forty one of these are nearby late-M dwarfs (d<30pc) with spectral types ranging from M5.0 to M8.5 computed from the spectral indices. One contaminant is probably an F-G main sequence star reddened by intervening dust and three stars that were not observed have previous classifications as M dwarfs in the literature. In this paper, we identify three M7.5, five M8.0, one M8.5 dwarf and confirm two new M8.0 dwarf members of the 25pc volume.
- ID:
- ivo://CDS.VizieR/J/MNRAS/353/589
- Title:
- Distances of planetary nebula
- Short Name:
- J/MNRAS/353/589
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distances of planetary nebulae (PNe) are still quite uncertain. Although observational estimates are available for a small proportion of PNe, based on statistical parallax and the like, such distances are very poorly determined for the majority of galactic PNe. In particular, estimates of so-called 'statistical' distance appear to differ by factors of ~2.7. We point out that there is a well-defined correlation between the 5-GHz luminosity of the sources, L_5_, and their brightness temperatures, T_B_.
- ID:
- ivo://CDS.VizieR/J/ApJ/571/512
- Title:
- Distances of white dwarf stars
- Short Name:
- J/ApJ/571/512
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The most recent version of the Catalog of Spectroscopically Identified White Dwarfs lists 2249 white dwarf stars. Among these stars are 109 white dwarfs that have either reliable trigonometric parallaxes or color-based distance moduli that place them at a distance within 20pc of the Sun. Most of these nearby white dwarfs are isolated stars, but 28 (25% of the sample) are in binary systems, including such well-known systems as Sirius A/B and Procyon A/B. There are also three double degenerate systems in this sample of the local white dwarf population. The sample of local white dwarfs is largely complete out to 13pc, and the local density of white dwarf stars is found to be 5.0+/-0.7x10^-3^pc^-3^, with a corresponding mass density of 3.4+/-0.5x10^-3^M{sun}_/pc^3^
- ID:
- ivo://CDS.VizieR/J/other/NewA/47.81
- Title:
- Distances of X-ray binaries
- Short Name:
- J/other/NewA/47.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The X-ray luminosity functions of galaxies have become a useful tool for population studies of X-ray binaries in them. The availability of long term light-curves of X-ray binaries with the All Sky X-ray Monitors opens up the possibility of constructing X-ray luminosity functions, by also including the intensity variation effects of the galactic X-ray binaries. We have constructed multiple realizations of the X-ray luminosity functions (XLFs) of Milky Way, using the long term light-curves of sources obtained in the 2-10keV energy band with the RXTE-ASM. The observed spread seen in the value of slope of both HMXB and LMXB XLFs are due to inclusion of variable luminosities of X-ray binaries in construction of these XLFs as well as finite sample effects. XLFs constructed for galactic HMXBs in the luminosity range 10^36^-10^39^erg/s is described by a power-law model with a mean power-law index of -0.48 and a spread due to variability of HMXBs as 0.19. XLFs constructed for galactic LMXBs in the luminosity range 10^36^-10^39^erg/s has a shape of cut-off power-law with mean power-law index of -0.31 and a spread due to variability of LMXBs as 0.07.
- ID:
- ivo://CDS.VizieR/I/347
- Title:
- Distances to 1.33 billion stars in Gaia DR2
- Short Name:
- I/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the majority of stars in the second Gaia data release, reliable distances cannot be obtained by inverting the parallax. A correct inference procedure must instead be used to account for the nonlinearity of the transformation and the asymmetry of the resulting probability distribution. Here we infer distances to almost all 1.33 billion stars with parallaxes published in the second Gaia data release. This is done using a weak distance prior that varies smoothly as a function of Galactic longitude and latitude according to a Galaxy model. The irreducible uncertainty in the distance estimate is characterized by the lower and upper bounds of an asymmetric confidence interval. Although more precise distances can be estimated for a subset of the stars using additional data (such as photometry), our goal is to provide purely geometric distance estimates, independent of assumptions about the physical properties of, or interstellar extinction towards, individual stars. We analyze the characteristics of the catalog and validate it using clusters.
- ID:
- ivo://CDS.VizieR/I/352
- Title:
- Distances to 1.47 billion stars in Gaia EDR3
- Short Name:
- I/352
- Date:
- 05 Jan 2022
- Publisher:
- CDS
- Description:
- Stellar distances constitute a foundational pillar of astrophysics. The publication of 1.47 billion stellar parallaxes from Gaia is a major contribution to this. Yet despite Gaia's precision, the majority of these stars are so distant or faint that their fractional parallax uncertainties are large, thereby precluding a simple inversion of parallax to provide a distance. Here we take a probabilistic approach to estimating stellar distances that uses a prior constructed from a three-dimensional model of our Galaxy. This model includes interstellar extinction and Gaia's variable magnitude limit. We infer two types of distance. The rst, geometric, uses the parallax together with a direction-dependent prior on distance. The second, photogeometric, additionally uses the colour and apparent magnitude of a star, by exploiting the fact that stars of a given colour have a restricted range of probable absolute magnitudes (plus extinction). Tests on simulated data and external validations show that the photogeometric estimates generally have higher accuracy and precision for stars with poor parallaxes. We provide a catalogue of 1.47 billion geometric and 1.35 billion photogeometric distances together with asymmetric uncertainty measures. Our estimates are quantiles of a posterior probability distribution, so they transform invariably and can therefore also be used directly in the distance modulus (5log10r-5). The catalogue may be downloaded or queried using ADQL at various sites (see http://www.mpia.de/~calj/gedr3 distances.html) where it can also be cross-matched with the Gaia catalogue.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A51
- Title:
- Distances to molecular clouds in SFR
- Short Name:
- J/A+A/633/A51
- Date:
- 14 Jan 2022 08:01:32
- Publisher:
- CDS
- Description:
- Accurate distances to local molecular clouds are critical for understanding the star and planet formation process, yet distance measurements are often obtained inhomogeneously on a cloud-by-cloud basis. We have recently developed a method which combines stellar photometric data with Gaia DR2 parallax measurements in a Bayesian framework to infer the distances of nearby dust clouds to a typical accuracy of ~5%. After refining the technique to target lower latitudes and incorporating deep optical data from DECam in the southern Galactic plane, we have derived a catalog of distances to molecular clouds in Reipurth (2008, Star Formation Handbook, vols I and II) which contains a large fraction of the molecular material in the solar neighborhood. Comparison with distances derived from maser parallax measurements towards the same clouds shows our method produces consistent distances with <10% scatter for clouds across our entire distance spectrum (150pc-2.5kpc). We hope this catalog of homogeneous distances will serve as a baseline for future work.
