Improving the cosmic distance ladder. Distance and structure of the Large Magellanic Cloud

Muraveva, T.; Clementini, G.; Palmer, M.

doi:10.1051/eas/1567049

Cited by 2 publications

(2 citation statements)

References 117 publications

(199 reference statements)

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“…Distance measurements in our galactic neighbourhood can be performed to high precision and accuracy, Gaia Collaboration et al (2018). Compared to that, extra-galactic distance measurements are more difficult, Cuesta et al (2015); Muraveva et al (2014); Tegmark (2002). Thus, with the development of an observation-based cosmic distance ladder still ongoing, cosmic distances are usually inferred from a measured (spectroscopic or photometric) redshift in combi-at angular position y in the source plane, which is given by…”

Section: Motivation From Previous Workmentioning

confidence: 99%

Generalized model-independent characterization of strong gravitational lenses V: reconstructing the lensing distance ratio by supernovae for a general Friedmann universe

Wagner

Meyer

2019

Monthly Notices of the Royal Astronomical Society

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We determine the cosmic expansion rate from supernovae of type Ia to set up a databased distance measure that does not make assumptions about the constituents of the universe, i.e. about a specific parametrisation of a Friedmann cosmological model. The scale, determined by the Hubble constant H 0 , is the only free cosmological parameter left in the gravitational lensing formalism. We investigate to which accuracy and precision the lensing distance ratio D is determined from the Pantheon sample. Inserting D and its uncertainty into the lensing equations for given H 0 , esp. the time-delay equation between a pair of multiple images, allows to determine lens properties, esp. differences in the lensing potential (∆φ), without specifying a cosmological model. We expand the luminosity distances into an analytic orthonormal basis, determine the maximum-likelihood weights for the basis functions by a globally optimal χ 2 -parameter estimation, and derive confidence bounds by Monte-Carlo simulations. For typical strong lensing configurations between z = 0.5 and z = 1.0, ∆φ can be determined with a relative imprecision of 1.7%, assuming imprecisions of the time delay and the redshift of the lens on the order of 1%. With only a small, tolerable loss in precision, the model-independent lens characterisation developed in this paper series can be generalised by dropping the specific Friedmann model to determine D in favour of a data-based distance ratio. Moreover, for any astrophysical application, the approach presented here, provides distance measures for z ≤ 2.3 that are valid in any homogeneous, isotropic universe with general relativity as theory of gravity.nation with a cosmological model that assigns the redshift to a cosmic distance. So far, the cosmological standard model, as most precisely measured by Planck Collaboration et al. (2018), is inserted into these distance measures.As one example, in the gravitational lensing formalism, angular diameter distances between the observer and the lens D l , the observer and the source Ds, and the distance between the lens and the source D ls appear in the lensing equations to scale the (multiple) images, the source, and the deflection potential with respect to each other. The so-called lensing distance ratio D(z l , zs) = D l Ds D ls ,appears, for instance, in the time delay τij between two multiple images i and j of the same background galaxy located

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Section: Motivation From Previous Workmentioning

confidence: 99%

Generalized model-independent characterization of strong gravitational lenses V: reconstructing the lensing distance ratio by supernovae for a general Friedmann universe

Wagner

Meyer

2019

Monthly Notices of the Royal Astronomical Society

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“…We also measured individual distances to the RR Lyrae in the cluster fields, after appropriately correcting for reddening. We used the period-luminosity relation of Muraveva et al (2015), applied to the fundamental pulsators (RRab) and also to the first-overtone pulsators (RRc), after fundamentalizing them by adding 0.127 to the logarithm of the period. The mean distances measured using all the RRab and RRc within 10' of the clusters that share the Sgr PMs are also listed in Table A1.…”

Section: Distances and Other Physical Parametersmentioning

confidence: 99%

Discovery of new globular clusters in the Sagittarius dwarf galaxy

Minniti,

Ripepi,

Fernández-Trincado

et al. 2021

Preprint

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Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way (MW). In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.

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Improving the cosmic distance ladder. Distance and structure of the Large Magellanic Cloud

Cited by 2 publications

References 117 publications

Generalized model-independent characterization of strong gravitational lenses V: reconstructing the lensing distance ratio by supernovae for a general Friedmann universe

Generalized model-independent characterization of strong gravitational lenses V: reconstructing the lensing distance ratio by supernovae for a general Friedmann universe

Discovery of new globular clusters in the Sagittarius dwarf galaxy

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