<i>HUBBLE SPACE TELESCOPE</i>PROPER MOTION (HSTPROMO) CATALOGS OF GALACTIC GLOBULAR CLUSTERS. I. SAMPLE SELECTION, DATA REDUCTION, AND NGC 7078 RESULTS

Bellini, Andrea; Anderson, Jay; Marel, Roeland P. van der; Watkins, Laura L.; King, I. R.; Bianchini, P.; Chanamé, Julio; Chandar, Rupali; Cool, A. M.; Ferraro, F. R.; Ford, H. C.; Massari, D.

doi:10.1088/0004-637x/797/2/115

Cited by 201 publications

(309 citation statements)

References 44 publications

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“…1). Following Bellini et al (2014) and Massari et al (2016), we also checked for spurious systematic trends of the measured PM components with spatial distribution, instrumental magnitude and colour, and found none. This is demonstrated in the top-and bottom-right panels of Fig.…”

Section: Data Analysis and Pm Measurementmentioning

confidence: 99%

The power of teaming up HST andGaia: the first proper motion measurement of the distant cluster NGC 2419

Massari

Posti

Helmi

et al. 2017

A&A

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Aims. We present the first measurement of the proper motion and orbit of the very distant and intriguing globular cluster NCG 2419. Methods. We have combined data from HST and Gaia DR1 to derive the relative proper motions of stars in the direction of the cluster. To tie these to an absolute reference frame, we have used a background galaxy located in the field. Results. We find the absolute proper motion of NGC 2419 to be (µ α cos(δ), µ δ ) = (−0.17 ± 0.26, −0.49 ± 0.17) mas yr −1 . We have integrated the orbit of the cluster in a Galactic potential and found it to oscillate between ∼53 kpc and ∼98 kpc on an almost polar orbit. This, and the fact that it shares the same sense of rotation around the Milky Way, make it very likely that NGC 2419 is a former cluster of the Sagittarius dwarf spheroidal galaxy.

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Section: Data Analysis and Pm Measurementmentioning

confidence: 99%

The power of teaming up HST andGaia: the first proper motion measurement of the distant cluster NGC 2419

Massari

Posti

Helmi

et al. 2017

A&A

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“…Only recently, with the advent of high quality proper motions (e.g. Bellini et al 2014) or the commissioning of powerful integral field spectrographs, such as MUSE (Bacon et al 2014), this picture has started to change.…”

Section: Introductionmentioning

confidence: 99%

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

Kamann

Husser

Brinchmann

et al. 2016

A&A

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We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than ∼18 000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse cluster, our analysis suggests a flattening of the surface brightness profile at the smallest radii. Although it is among the nearest globular clusters, the low velocity dispersion of NGC 6397 of <5 km s −1 imposes heavy demands on the quality of the kinematical data. We show that despite its limited spectral resolution, MUSE reaches an accuracy of 1 km s −1 in the analysis of stellar spectra. We find slight evidence for a rotational component in the cluster and the velocity dispersion profile that we obtain shows a mild central cusp. To investigate the nature of this feature, we calculate spherical Jeans models and compare these models to our kinematical data. This comparison shows that if a constant mass-to-light ratio is assumed, the addition of an intermediate-mass black hole with a mass of 600 M brings the model predictions into agreement with our data, and therefore could be at the origin of the velocity dispersion profile. We further investigate cases with varying mass-to-light ratios and find that a compact dark stellar component can also explain our observations. However, such a component would closely resemble the black hole from the constant mass-to-light ratio models as this component must be confined to the central ∼5 of the cluster and must have a similar mass. Independent constraints on the distribution of stellar remnants in the cluster or kinematic measurements at the highest possible spatial resolution should be able to distinguish the two alternatives.

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“…Kallivayalil et al 2013); of the Sagittarius stream (Sohn et al 2015); and of globular clusters (e.g. Bellini et al 2014). The HST will continue to provide proper motion measurements for more systems, while in the near future a major contribution to proper motion studies is expected from the European Space Agency mission Gaia.…”

Section: Introductionmentioning

confidence: 99%

The VMC survey

Cioni

Bekki

Girardi

et al. 2016

A&A

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Aims. In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motions of different stellar populations in a tile of 1.5 deg 2 in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Methods. Stars of the three main stellar components are selected according to their spatial distributions and their distributions in colour−magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple K s -band observations for stars as faint as K s = 19 mag. Proper motions are derived from the slope of the best-fitting line among ten VMC epochs over a time baseline of ∼1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. Results. The resulting absolute proper motion of 47 Tuc is (μ α cos(δ), μ δ ) = (+7.26 ± 0.03, −1.25 ± 0.03) mas yr −1 . This measurement refers to about 35 000 sources distributed between 10 and 60 from the cluster centre. For the SMC we obtain (μ α cos(δ), μ δ ) = (+1.16 ± 0.07, −0.81 ± 0.07) mas yr −1 from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line of sight (l = 305.9, b = −44.9) of this VISTA tile is (μ α cos(δ), μ δ ) = (+10.22 ± 0.14, −1.27 ± 0.12) mas yr −1 and has been calculated from about 4000 sources. Systematic uncertainties associated with the astrometric reference system are 0.18 mas yr −1 . Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.

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HUBBLE SPACE TELESCOPEPROPER MOTION (HSTPROMO) CATALOGS OF GALACTIC GLOBULAR CLUSTERS. I. SAMPLE SELECTION, DATA REDUCTION, AND NGC 7078 RESULTS

Cited by 201 publications

References 44 publications

The power of teaming up HST andGaia: the first proper motion measurement of the distant cluster NGC 2419

The power of teaming up HST andGaia: the first proper motion measurement of the distant cluster NGC 2419

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

The VMC survey

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