A Large Local Rotational Speed for the Galaxy Found from Proper Motions: Implications for the Mass of the Milky Way

1999 ◽  
Vol 524 (1) ◽  
pp. L39-L42 ◽  
Author(s):  
René A. Méndez ◽  
Imants Platais ◽  
Terrence M. Girard ◽  
Vera Kozhurina-Platais ◽  
William F. van Altena
Keyword(s):  
Rotational Speed ◽  
Milky Way ◽  
Proper Motions ◽  
The Galaxy

THE EARLY GREAT DEBATE: A COMMENT ON IBN AL-HAYTHAM‘S WORK ON THE LOCATION OF THE MILKY WAY WITH RESPECT TO THE EARTH

2018 ◽  
Vol 28 (1) ◽  
pp. 1-30 ◽  
Author(s):  
Andreas Eckart
Keyword(s):  
Milky Way ◽  
Last Millennium ◽  
The Moon ◽  
Proper Motions ◽  
Stellar Proper Motions ◽  
The Earth ◽  
Great Debate ◽  
The Galaxy ◽  
Early Translation ◽  
Critical Translation

AbstractAt the very beginning of the last millennium Ibn al-Haytham greatly contributed to the investigation of the Milky Way. Here, the only three currently known versions of his work on the location of the Milky Way are compared to each other and discussed. A comparison of the texts and an early translation into German by E. Wiedemann in 1906 reveals several differences that triggered a new critical translation of the passed down text. We give detailed comments on the work and check the validity of Ibn al-Haytham's arguments. We also discuss his work in the framework of the ‘Great Debate’ on the Milky Way that took place around 1920, more than a decade after Wiedemann's translation. We find that Ibn al-Haytham's work is certainly at the peak of the unaided-eye era of the Milky Way's discovery. Through his own argumentation and in comparison to Ptolemy's observations Ibn al-Haytham clearly identifies the Galaxy as an extraterrestrial body that is not part of the atmosphere but much further away than the Moon. With some of his statements on the stellar positions passed down by Ptolemy, Ibn al-Haytham also anticipates the concept of stellar proper motions.

scholarly journals 10.2. High proper motions in the vicinity of Sgr A∗: unambiguous evidence for a massive central black hole

1998 ◽  
Vol 184 ◽  
pp. 433-434
Author(s):  
A. M. Ghez ◽  
B. L. Klein ◽  
C. McCabe ◽  
M. Morris ◽  
E. E. Becklin
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Galactic Center ◽  
Robust Method ◽  
Proper Motions ◽  
Central Black Hole ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Sgr A

Although the notion that the Milky Way galaxy contains a supermassive central black hole has been around for more than two decades, it has been difficult to prove that one exists. The challenge is to assess the distribution of matter in the few central parsecs of the Galaxy. Assuming that gravity is the dominant force, the motion of the stars and gas in the vicinity of the putative black hole offers a robust method for accomplishing this task, by revealing the mass interior to the radius of the objects studied. Thus objects located closest to the Galactic Center provide the strongest constraints on the black hole hypothesis.

scholarly journals A New Absolute Proper Motion Determination of Leo I Using HST/WFPC2 Images and Gaia EDR3

2021 ◽  
Vol 163 (1) ◽  
pp. 1
Author(s):  
Dana I. Casetti-Dinescu ◽  
Caitlin K. Hansen ◽  
Terrence M. Girard ◽  
Vera Kozhurina-Platais ◽  
Imants Platais ◽  
...  
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Proper Motions ◽  
Large Area ◽  
Field Of Study ◽  
Data Set ◽  
Polar Structure ◽  
The Galaxy ◽  
The Absolute

Abstract We measure the absolute proper motion of Leo I using a WFPC2/HST data set that spans up to 10 yr to date the longest time baseline utilized for this satellite. The measurement relies on ∼2300 Leo I stars located near the center of light of the galaxy; the correction to absolute proper motion is based on 174 Gaia EDR3 stars and 10 galaxies. Having generated highly precise, relative proper motions for all Gaia EDR3 stars in our WFPC2 field of study, our correction to the absolute EDR3 system does not rely on these Gaia stars being Leo I members. This new determination also benefits from a recently improved astrometric calibration of WFPC2. The resulting proper-motion value, (μ α , μ δ ) = (−0.007 ± 0.035, − 0.119 ± 0.026) mas yr−1 is in agreement with recent, large-area, Gaia EDR3-based determinations. We discuss all the recent measurements of Leo I’s proper motion and adopt a combined, multistudy average of ( μ α 3 meas , μ δ 3 meas ) = ( − 0.036 ± 0.016 , − 0.130 ± 0.010 ) mas yr−1. This value of absolute proper motion for Leo I indicates its orbital pole is well aligned with that of the vast polar structure, defined by the majority of the brightest dwarf spheroidal satellites of the Milky Way.

scholarly journals The RAVE harvest: from the relation between abundances and kinematic of the Milky Way stars to tools for the abundance analysis of the spectra

2013 ◽  
Vol 9 (S298) ◽  
pp. 292-297
Author(s):  
Corrado Boeche ◽  
Keyword(s):  
Milky Way ◽  
Radial Velocities ◽  
Proper Motions ◽  
Chemical Abundances ◽  
Stellar Spectra ◽  
Chemical Gradients ◽  
Single Process ◽  
The Galaxy ◽  
Nearby Stars ◽  
Kinematic Information

AbstractRAVE is a spectroscopic survey of the Milky Way which collected more than 500,000 stellar spectra of nearby stars in the Galaxy. The RAVE consortium analysed these spectra to obtain radial velocities, stellar parameters and chemical abundances. These data, together with spatial and kinematic information like positions, proper motions, and distance estimations, make the RAVE database a rich source for galactic archaeology. I present recent investigations on the chemo-kinematic relations and chemical gradients in the Milky Way disk using RAVE data and compare our results with the Besançon models. I also present the code SPACE, an evolution of the RAVE chemical pipeline, which integrates the measurements of stellar parameters and chemical abundances in one single process.

Extra-tidal features using Gaia DR2

2019 ◽  
Vol 14 (S351) ◽  
pp. 420-421
Author(s):  
Julio A. Carballo-Bello
Keyword(s):  
Mass Distribution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Space Mission ◽  
Cluster Center ◽  
Proper Motions ◽  
The Galaxy ◽  
Tidal Tails ◽  
Gaia Dr2

AbstractIn recent years, we have gathered enough evidence showing that most of the Galactic globular clusters extend well beyond their King tidal radii and fill their Jacobi radii in the form of “extended stellar haloes”. In some cases, because of the interaction with the Milky Way, stars are able to exceed the Jacobi radius, generating tidal tails which may be used to trace the mass distribution in the Galaxy. In this work, we use the precious information provided by the space mission Gaia (photometry, parallaxes and proper motions) to analyze NGC 362 in the search for member stars in its surroundings. Our preliminar results suggest that it is possible to identify member stars and tidal features up to distances of a few degrees from the globular cluster center.

Structure and Kinematics of the Milky Way

2017 ◽  
Vol 13 (S336) ◽  
pp. 148-153 ◽  
Author(s):  
Mark J. Reid
Keyword(s):  
Rotation Curve ◽  
Milky Way ◽  
Spiral Structure ◽  
Galactic Center ◽  
Rotation Speed ◽  
Information Modeling ◽  
High Mass ◽  
Proper Motions ◽  
Dimensional Phase Space ◽  
The Galaxy

AbstractMaser astrometry is now providing parallaxes with accuracies of ±10 micro-arcseconds, which corresponds to 10% accuracy at a distance of 10 kpc! The VLBA BeSSeL Survey and the Japanese VERA project have measured ≈200 parallaxes for masers associated with young, high-mass stars. Since these stars are found in spiral arms, we now are directly mapping the spiral structure of the Milky Way. Combining parallaxes, proper motions, and Doppler velocities, we have complete 6-dimensional phase-space information. Modeling these data yields the distance to the Galactic Center, the rotation speed of the Galaxy at the Sun, and the nature of the rotation curve.

scholarly journals A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars

2020 ◽  
Vol 501 (2) ◽  
pp. 1690-1700
Author(s):  
Julio A Carballo-Bello ◽  
David Martínez-Delgado ◽  
Jesús M Corral-Santana ◽  
Emilio J Alfaro ◽  
Camila Navarrete ◽  
...  
Keyword(s):  
Milky Way ◽  
Dwarf Galaxy ◽  
Line Of Sight ◽  
Proper Motions ◽  
Large Area ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
Pollution Area ◽  
New Evidence ◽  
Astrometric Data

ABSTRACT We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour–magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypothetical core. The stellar overdensity extends on a large area of the sky at low Galactic latitudes, below the plane, and in the range 230° < ℓ < 255°. According to the orbit derived for Canis Major, it presents an on-plane rotation around the Milky Way. Moreover, additional overdensities of Blue Plume stars are found around the plane and across the Galaxy, proving that these objects are not only associated with that structure. The spatial distribution of these stars, derived using Gaia astrometric data, confirms that the detection of the Canis Major overdensity results more from the warped structure of the Milky Way disc than from the accretion of a dwarf galaxy.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

scholarly journals The globular cluster system of the Auriga simulations

2020 ◽  
Vol 496 (1) ◽  
pp. 638-648 ◽  
Author(s):  
Timo L R Halbesma ◽  
Robert J J Grand ◽  
Facundo A Gómez ◽  
Federico Marinacci ◽  
Rüdiger Pakmor ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Milky Way ◽  
Cluster Formation ◽  
Solar Radius ◽  
High Mass ◽  
Formation Model ◽  
The Galaxy ◽  
High Mass Loss ◽  
Globular Cluster System ◽  
Varying Mass

ABSTRACT We investigate whether the galaxy and star formation model used for the Auriga simulations can produce a realistic globular cluster (GC) population. We compare statistics of GC candidate star particles in the Auriga haloes with catalogues of the Milky Way (MW) and Andromeda (M31) GC populations. We find that the Auriga simulations do produce sufficient stellar mass for GC candidates at radii and metallicities that are typical for the MW GC system (GCS). We also find varying mass ratios of the simulated GC candidates relative to the observed mass in the MW and M31 GCSs for different bins of galactocentric radius metallicity (rgal–[Fe/H]). Overall, the Auriga simulations produce GC candidates with higher metallicities than the MW and M31 GCS and they are found at larger radii than observed. The Auriga simulations would require bound cluster formation efficiencies higher than 10 per cent for the metal-poor GC candidates, and those within the Solar radius should experience negligible destruction rates to be consistent with observations. GC candidates in the outer halo, on the other hand, should either have low formation efficiencies, or experience high mass-loss for the Auriga simulations to produce a GCS that is consistent with that of the MW or M31. Finally, the scatter in the metallicity as well as in the radial distribution between different Auriga runs is considerably smaller than the differences between that of the MW and M31 GCSs. The Auriga model is unlikely to give rise to a GCS that can be consistent with both galaxies.

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