The Lutz–Kelker paradox

Francis, Charles

doi:10.1093/mnrasl/slu103

Cited by 14 publications

(24 citation statements)

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“…Finally, we also adopt the distance to the young, compact nebula K 3-35 , determined using VLBI Exploration of Radio Astrometry (VERA) array observations of a bright water maser in the nebula 2 . Note that the trigonometric method is susceptible to the socalled Lutz-Kelker (L-K) bias (Lutz & Kelker 1973;Smith 2003Smith , 2006Francis 2014) which causes measured parallaxes to be systematically greater than their actual values in a statistical sense, and is broadly related to the Trumpler-Weaver bias (Trumpler & Weaver 1953). As emphasised by van Leeuwen (2007) and Francis (2014), the L-K bias is a sample statistical correction, and has not been applied to individual distances.…”

Section: Trigonometric Distancesmentioning

confidence: 99%

“…Note that the trigonometric method is susceptible to the socalled Lutz-Kelker (L-K) bias (Lutz & Kelker 1973;Smith 2003Smith , 2006Francis 2014) which causes measured parallaxes to be systematically greater than their actual values in a statistical sense, and is broadly related to the Trumpler-Weaver bias (Trumpler & Weaver 1953). As emphasised by van Leeuwen (2007) and Francis (2014), the L-K bias is a sample statistical correction, and has not been applied to individual distances. In the future, the number of trigonometric parallaxes for CSPNe will be revolutionised with the results from the Gaia satellite (Perryman et al 2001;Bailer-Jones 2002).…”

Section: Trigonometric Distancesmentioning

confidence: 99%

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The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

Frew¹,

Parker²,

Bojičić³

2015

Monthly Notices of the Royal Astronomical Society

169

127

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Measuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the Hα surface brightness -radius or S Hα -r relation, which addresses this problem. We developed this relation from a critically evaluated sample of primary calibrating PNe. The robust nature of the method results from our revised calibrating distances with significantly reduced systematic uncertainties, and the recent availability of high-quality data, including updated nebular diameters and integrated Hα fluxes. The S Hα -r technique is simple in its application, requiring only an angular size, an integrated Hα flux, and the reddening to the PN. From these quantities, an intrinsic radius is calculated, which when combined with the angular size, yields the distance directly. Furthermore, we have found that optically thick PNe tend to populate the upper bound of the trend, while optically-thin PNe fall along the lower boundary in the S Hα -r plane. This enables sub-trends to be developed which offer even better precision in the determination of distances, as good as 18 per cent in the case of optically-thin, high-excitation PNe. This is significantly better than any previous statistical indicator. We use this technique to create a catalogue of statistical distances for over 1100 Galactic PNe, the largest such compilation in the literature to date. Finally, in an appendix, we investigate both a set of transitional PNe and a range of PN mimics in the S Hα -r plane, to demonstrate its use as a diagnostic tool. Interestingly, stellar ejecta around massive stars plot on a tight locus in S Hα -r space with the potential to act as a separate distance indicator for these objects.

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Section: Trigonometric Distancesmentioning

confidence: 99%

Section: Trigonometric Distancesmentioning

confidence: 99%

The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

Frew¹,

Parker²,

Bojičić³

2015

Monthly Notices of the Royal Astronomical Society

169

127

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“…If we apply the σ π < 20% condition, the sample is reduced to 176 objects and M dyn > M ph for 84 of them (47.7%). This means that we generally underestimate stellar luminosity and, hence, M ph for systems with a larger error in the parallax (see discussion in Francis, 2014).…”

Section: The Sample Selection Criteriamentioning

confidence: 98%

New distances for a selected set of visual binaries with inconsistent dynamical masses

Tamazian

Malkov

Docobo

et al. 2016

Astrophys Space Sci

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We have selected a set of 17 visual binaries that demonstrate great inconsistency between the systemic mass obtained through Kepler's Third Law as compared to that calculated through standard mass-luminosity and mass-spectrum relationships. A careful inspection of orbital data and parallaxes showed that the current orbits of nine binaries (WDS 00155−1608, WDS 00174+0853, WDS 05017+2050, WDS 06410+0954, WDS 16212−2536, WDS 17336−3706, WDS 19217−1557, WDS 20312+1116, and WDS 21118+5959) do not need to be improved, instead we recommend different parallax (distance) value for them. On the other hand, we considered that eight orbits (WDS 02366+1227, WDS 02434-6643, WDS 03244-1539, WDS 08507+1800, WDS 09128−6055, WDS 11532-1540, WDS 17375+2419, and WDS 22408−0333) had to be improved. Due to various reasons mentioned in this paper, their distances should most likely be corrected unless better orbital solutions and/or more precise parallaxes are reported. To obtain consistent mass values, the use of the dynamical parallax is still recommended for 5 out of the 8 improved orbits. For WDS 02434−6643, WDS 09128−6055, and WDS 11532−1540, the improvement itself yields reasonable mass sums while maintaining π Hip within a 1-2 σ margin. New distance estimates for 16 stars (mainly based on the obtained dynamical parallaxes) and individual comments for all objects are presented and discussed.

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“…Though the LKE is defined as a statistical offset with a sample of stars of a given class, Lutz & Kelker (1973) argue that their defined correction could be to be used to correct the derived absolute magnitudes for individual stars, and, to some extent, it traditionally has. More recently, the logic behind this practice and Lutz & Kelker's original assertion that the correction could be applied to individual stars has been challenged (van Leeuwen 2007a;Smith 2003;Francis 2014). Irregardless of this "Lutz-Kelker Paradox", it is nonetheless naturally the case that stars with a larger parallax error will show a larger error in derived absolute magnitudes, and, as a class, would be expected to exhibit a larger systematic offset; it is our goal to assess whether this phenomenon has any significant effect in our comparison of A35 absolute magnitudes to those derived from Hipparcos parallaxes.…”

Section: The Lutz-kelker Effectmentioning

confidence: 99%

“…The LKE as applied to the Hipparcos catalog, has been explored by numerous authors, including, but not limited to, Oudmaijer et al (1998), Brown et al (1998), andvan Leeuwen (2007a). Generally, it is advised to reject all stars with fractional errors greater than 10% or σ(π)/π > 0.10, but a full treatment of the LKE, and any other relevant biases, requires detailed modeling of the specific sample in question (e.g., Sandage & Saha 2002;van Leeuwen 2007a;Smith 2003;Francis 2014). While the very form and magnitude of the LKE has also been reassessed and debated (see previous references) we adopt the formalism of Sandage & Saha (2002) for our calculations, which are primarily illustrative; because the latter treatments tend to find bias corrections of an overall smaller magnitude, our examples can then be seen as an upper limit to the influence on the Hipparcos data.…”

Section: The Lutz-kelker Effectmentioning

confidence: 99%

Life in the Outer Limits: Insights on Hierarchical Assembly from Stellar Halos in the Local Universe

Beaton¹

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ivOwing to their large dynamical timescales, the stellar haloes of Milky Way (MW) sized galaxies represent ideal environments to test modern theories of galaxy formation within the Λ-CDM paradigm. Only in stellar haloes can the remnants of hierarchical accretion both be preserved over long timescales as in-tact dwarf satellites or as tidal debris and be easily distinguished from the underlying smooth structure. Stellar haloes, however, remain some of the most difficult galactic structures to study due to their large angular extent (to R virial ) and extremely low surface brightness (∼> 30 mag arcsec 2 ). Thus, the basic properties of stellar haloes -the overall stellar distribution, substructure fraction, global kinematics and detailed stellar contentremain relatively unconstrained.First, we revisit the development of the modern theory of stellar evolutionin particular, the visualization of this evolution from the Hertzsprung-Russell dia- allowed the SPLASH project to identify bone fide M 31 halo member stars at 32 mag arcsec −2 , which are buried beneath a Galactic foreground of many times higher surface brightness. This thesis presents a campaign that has resulted in the largest sample of stellar halo member stars beyond R proj ∼ 120 kpc (∼1/3 R virial ) in any galaxy. We utilize the large angular extent of these member stars on the sky (R > 8 • )to measure the transverse motion of the M 31 system, using the variable projection of this motion onto its member stars at large angular separations. The technique is found to be comparable in precision to other statistical and direct proper motion studies and this effort is the first step to a global kinematical modelling of the halo using this unique kinematic sample.Third, we use deep imaging to 29 mag arcsec −2 to reveal merger debris NGC 5387, an edge-on disk disk galaxy similar to the Milky Way. The debris are found to be consistent with the merger of a dwarf satellite galaxy at a 1:10 mass ratio. The progenitor of the tidal debris is identified as a relatively compact (∼1 kpc) region undergoing extreme star formation at a rate of 2 M ⊙ year −1 , consistent with a massive star density of 1200 stars kpc −1 -making it similar to the conditions observed in super star clusters typically identified in more massive mergers. Despite showing chemical properties consistent with a galaxy of its original mass, we show that this galaxy is unique among samples of nearby dwarf galaxies regardless of environment, both in its integrated colors and in its star forming properties. From comparison to detailed numerical modelling, we infer the extreme star formation was induced by a recent passage through the NGC 5387 disk and that the satellite remnant could continue forming stars through an additional disk passage. We show that were this galaxy undisturbed, i.e., had its stellar halo not been stripped, it would have colors vi consistent with those objects in the "green valley" for dwarf satellites, suggesting opportunities to probe extreme star formation environments nee...

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The Lutz–Kelker paradox

Cited by 14 publications

References 14 publications

The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

New distances for a selected set of visual binaries with inconsistent dynamical masses

Life in the Outer Limits: Insights on Hierarchical Assembly from Stellar Halos in the Local Universe

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