UBV Photometry for 31 Galactic Globular Clusters

For many reasons, it is important to have a sound body of reliable photometry for the globular clusters in the Milky Way galaxy. Given the striking appearance of the globular clusters and their historical and astrophysical interest, it is perhaps surprising that the available photoelectric photometry for globular clusters is of mixed quality (see Harris and Racine 1979). Here I present a homogeneous body of photometry through a single aperture and in the UBV system for 31 globular clusters south of declination +12°.

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An Exercise for Introductory Earth-Science Classes on Using Globular Clusters to Determine the Size of the Milky Way Galaxy and Our Position in It

Journal of Geological Education ◽

10.5408/0022-1368-41.5.490 ◽

1993 ◽

Vol 41 (5) ◽

pp. 490-496

Author(s):

James H. Shea

Keyword(s):

Globular Clusters ◽

Milky Way ◽

Earth Science ◽

Milky Way Galaxy ◽

Science Classes

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Relative Ages of Galactic Globular Clusters: Clues to the Formation and Evolution of the Milky Way

Publications of the Astronomical Society of the Pacific ◽

10.1086/316556 ◽

2000 ◽

Vol 112 (770) ◽

pp. 575-576 ◽

Cited By ~ 3

Author(s):

Alfred Rosenberg

Keyword(s):

Globular Clusters ◽

Milky Way ◽

Formation And Evolution ◽

Galactic Globular Clusters

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The Effect of Dwarf Galaxies on the Tidal Tails of Globular Clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab3505 ◽

2021 ◽

Author(s):

Nada El-Falou ◽

Jeremy J Webb

Keyword(s):

Globular Clusters ◽

Milky Way ◽

Dwarf Galaxies ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Size And Shape ◽

The Galaxy ◽

Galaxy Model ◽

Galactic Globular Clusters ◽

Tidal Tails

Abstract The tidal tails of globular clusters have been shown to be sensitive to the external tidal field. We investigate how Galactic globular clusters with observed tails are affected by satellite dwarf galaxies by simulating tails in galaxy models with and without dwarf galaxies. The simulations indicate that tidal tails can be subdivided into into three categories based on how they are affected by dwarf galaxies: 1) dwarf galaxies perturb the progenitor cluster’s orbit (NGC 4590, Pal 1, Pal 5), 2) dwarf galaxies perturb the progenitor cluster’s orbit and individual tail stars (NGC 362, NGC 1851, NGC 4147, NGC 5466, NGC 7492, Pal 14, Pal 15), and 3) dwarf galaxies negligibly affect tidal tails (NGC 288, NGC 5139, NGC 5904, Eridanus). Perturbations to a cluster’s orbit occur when dwarf galaxies pass within its orbit, altering the size and shape of the orbital and tail path. Direct interactions between one or more dwarf galaxies and tail stars lead to kinks and spurs, however we find that features are more difficult to observe in projection. We further find that the tails of Pal 5 are shorter in the galaxy model with dwarf galaxies as it is closer to apocentre, which results in the tails being compressed. Additional simulations reveal that differences between tidal tails in the two galaxy models are primarily due to the Large Magellanic Cloud. Understanding how dwarf galaxies affect tidal tails allows for tails to be used to map the distribution of matter in dwarf galaxies and the Milky Way.

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Astrometry and Galactic Structure

Symposium - International Astronomical Union ◽

10.1017/s0074180900047781 ◽

1994 ◽

Vol 161 ◽

pp. 425-434

Author(s):

S.R. Majewski

Keyword(s):

Proper Motion ◽

Globular Clusters ◽

Milky Way ◽

Galactic Structure ◽

Proper Motions ◽

Future Prospects ◽

The Status ◽

Galactic Globular Clusters ◽

Remarkable Agreement

The application of astrometric surveys to understanding the structure and kinematics of the Milky Way is discussed, with particular emphasis on some of the issues expected to be addressed in the next decade or so. It is shown that the results of complete proper motion surveys of field stars at the Galactic poles are in remarkable agreement concerning the global kinematics of stars as a function of distance, but that significant differences exist in how these data are decomposed to derive the kinematics of individual Galactic components. The status and future prospects regarding the measurement of proper motions and orbits for Galactic globular clusters and satellites are also discussed.

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Revision of the [Fe/H] – φ31–Prelationship for RRc variables

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313015056 ◽

2013 ◽

Vol 9 (S301) ◽

pp. 461-462

Author(s):

Siobahn Morgan

Keyword(s):

Globular Clusters ◽

Milky Way ◽

Fourier Coefficients ◽

Rr Lyrae ◽

Best Fitting ◽

Low Metallicity ◽

Type C ◽

Galactic Globular Clusters ◽

The Relationship

AbstractThe relationship derived by Morganet al. (2007) for type-c RR Lyrae variables (RRc) between values of [Fe/H] – φ31–Phas been revised and expanded. New relationships are based upon Fourier coefficients of 163 RRc variables in 19 Galactic globular clusters using the metallicity scales of Harris (2010), Zinn & West (1984) and Carrettaet al. (2009). This larger database includes more low-metallicity clusters ([Fe/H] < −2.0), and the best fitting relations are found to depend upon values of logPrather thanP. The new relations are applied to various populations of RRc including Milky Way field variables, LMC globular clusters variables, ω Cen RRc, and RRc in various OGLE III databases.

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The GOTHAM survey: chemical evolution of Milky Way globular clusters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317007086 ◽

2017 ◽

Vol 13 (S334) ◽

pp. 25-28

Author(s):

Bruno Dias ◽

Beatriz Barbuy ◽

Ivo Saviane ◽

Enrico V. Held ◽

Gary Da Costa ◽

...

Keyword(s):

Chemical Evolution ◽

Globular Cluster ◽

Globular Clusters ◽

Stellar Population ◽

Milky Way ◽

Open Clusters ◽

Giant Stars ◽

Globular Cluster System ◽

Galactic Globular Clusters ◽

Red Giant

AbstractMilky Way globular clusters are excellent laboratories for stellar population detailed analysis that can be applied to extragalactic environments with the advent of the 40m-class telescopes like the ELT. The globular cluster population traces the early evolution of the Milky Way which is the field of Galactic archaeology. We present our GlObular clusTer Homogeneous Abundance Measurement (GOTHAM) survey. We derived radial velocities, Teff, log(g), [Fe/H], [Mg/Fe] for red giant stars in one third of all Galactic globular clusters that represent well the Milky Way globular cluster system in terms of metallicity, mass, reddening, and distance. Our method is based on low-resolution spectroscopy and is intrinsically reddening free and efficient even for faint stars. Our [Fe/H] determinations agree with high-resolution results to within 0.08 dex. The GOTHAM survey provides a new metallicity scale for Galactic globular clusters with a significant update of metallicities higher than [Fe/H] > -0.7. We show that the trend of [Mg/Fe] with metallicity is not constant as previously found, because now we have more metal-rich clusters. Moreover, peculiar clusters whose [Mg/Fe] does not match Galactic stars for a given metallicity are discussed. We also measured the CaII triplet index for all stars and we show that the different chemical evolution of Milky Way open clusters, field stars, and globular clusters implies different calibrations of calcium triplet to metallicity.

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Evidence for two early accretion events that built the Milky Way stellar halo

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1770 ◽

2019 ◽

Vol 488 (1) ◽

pp. 1235-1247 ◽

Cited By ~ 86

Author(s):

G C Myeong ◽

E Vasiliev ◽

G Iorio ◽

N W Evans ◽

V Belokurov

Keyword(s):

Globular Cluster ◽

Total Mass ◽

Globular Clusters ◽

Milky Way ◽

Dwarf Galaxy ◽

High Energy ◽

Stellar Mass ◽

Milky Way Galaxy ◽

Stellar Halo ◽

Chemical Evidence

AbstractThe Gaia Sausage is the major accretion event that built the stellar halo of the Milky Way galaxy. Here, we provide dynamical and chemical evidence for a second substantial accretion episode, distinct from the Gaia Sausage. The Sequoia Event provided the bulk of the high-energy retrograde stars in the stellar halo, as well as the recently discovered globular cluster FSR 1758. There are up to six further globular clusters, including ω Centauri, as well as many of the retrograde substructures in Myeong et al., associated with the progenitor dwarf galaxy, named the Sequoia. The stellar mass in the Sequoia galaxy is ∼5 × 10 M⊙ , whilst the total mass is ∼1010 M⊙ , as judged from abundance matching or from the total sum of the globular cluster mass. Although clearly less massive than the Sausage, the Sequoia has a distinct chemodynamical signature. The strongly retrograde Sequoia stars have a typical eccentricity of ∼0.6, whereas the Sausage stars have no clear net rotation and move on predominantly radial orbits. On average, the Sequoia stars have lower metallicity by ∼0.3 dex and higher abundance ratios as compared to the Sausage. We conjecture that the Sausage and the Sequoia galaxies may have been associated and accreted at a comparable epoch.

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Structure of the nuclear stellar cluster of the Milky Way galaxy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314000623 ◽

2013 ◽

Vol 9 (S303) ◽

pp. 228-229

Author(s):

Devaky Kunneriath ◽

Rainer Schödel ◽

Susan Stolovy ◽

Anja Feldmeier

Keyword(s):

Globular Clusters ◽

Surface Brightness ◽

Milky Way ◽

Galactic Center ◽

Host Galaxies ◽

Dynamical Mass ◽

Milky Way Galaxy ◽

Stellar Cluster ◽

Nuclear Cluster ◽

Sgr A

AbstractNuclear star clusters are unambiguously detected in about 50–70% of spiral and spheroidal galaxies. They have typical half-light radii of 2–5 pc, dynamical mass ranging from 106 – 107 M⊙, are brighter than globular clusters, and obey similar scaling relations with host galaxies as supermassive black holes. The nuclear stellar cluster (NSC) which surrounds Sgr A*, the SMBH at the center of our galaxy, is the nearest nuclear cluster to us, and can be resolved to scales of milliparsecs. The strong and highly variable extinction towards the Galactic center makes it very hard to infer the intrinsic properties of the NSC (structure and size). We attempt a new way to infer its properties by using Spitzer MIR images in a wavelength range 3–8 μm where the extinction is at a minimum, and the NSC clearly stands out as a separate structure. We present results from our analysis, including extinction-corrected images and surface brightness profiles of the central few hundred parsecs of the Milky Way.

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