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Related papers: A Measurement of Diffusion in 47 Tucanae

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I present empirical measurements of the rate of relaxation in N-body simulations of stable spherical systems and distinguish two separate types of relaxation: energy diffusion that is largely independent of particle mass, and energy…

Astrophysics of Galaxies · Physics 2015-09-16 J. A. Sellwood

We present a fast, efficient and easy to apply computational method for the detection of planetary transits in large photometric datasets. The code has been specifically produced to analyse an ensemble of 21,950 stars in the globular…

Astrophysics · Physics 2009-11-10 David T. F Weldrake , Penny D Sackett

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…

Evaporative evolution of stellar clusters is shown to be relaxation limited when the number of stars satisfies $N>>N_c$, where $N_c\simeq 1600$. For a Maxwell velocity distribution that extends beyond the escape velocity, this process is…

Astrophysics of Galaxies · Physics 2015-06-03 Maurice H. P. M. van Putten

Despite their shared origin, members of globular clusters display star-to-star variations in composition. The observed pattern of element abundances is unique to these stellar environments, and cannot be fully explained by any proposed…

Solar and Stellar Astrophysics · Physics 2023-10-19 Roman Gerasimov , Adam J. Burgasser , Ilaria Caiazzo , Derek Homeier , Harvey B. Richer , Matteo Correnti , Jeremy Heyl

We consider a potentially new class of gravitational wave sources consisting of a white dwarf coalescing into a massive black hole in the mass range ~10^4-10^5\msun. These sources are of particular interest because the gravitational wave…

Astrophysics · Physics 2009-11-13 A. Sesana , A. Vecchio , M. Eracleous , S. Sigurdsson

We investigate the sample of 1175 new nonmagnetic DA white dwarfs with the effective temperatures T_eff > 12000 K, which were extracted from the Data Release 1 of the Sloan Digital Sky Survey. We determined masses, radii, and bolometric…

Astrophysics · Physics 2009-11-10 J. Madej , M. Nalezyty , L. G. Althaus

Observations of white dwarfs in the globular clusters NGC 6397 and Omega Centauri indicate that these stars may get a velocity kick during their time as giants. If the mass loss while on the asymptotic giant branch is slightly asymmetric,…

Solar and Stellar Astrophysics · Physics 2015-05-13 Jeremy S. Heyl , Matthew Penrice

Using deep Hubble Space Telescope imaging, color-magnitude diagrams are constructed for the globular clusters 47 Tuc and NGC 6397. As expected, because of its lower metal abundance, the main sequence of NGC 6397 lies well to the blue of…

We report the first use of the Rutgers Imaging Fabry-Perot Spectrophotometer to study the dynamics of the cores of globular clusters. We have obtained velocities for cluster stars by tuning the Fabry-Perot to take a series of narrow-band…

Astrophysics · Physics 2009-10-22 K. Gebhardt , C. Pryor , T. B. Williams , J. E. Hesser

It is generally accepted today that Galactic globular clusters (GGCs) consist of at least two generations of stars that are different in their chemical composition and perhaps age. However, knowledge about the kinematical properties of…

Solar and Stellar Astrophysics · Physics 2014-09-05 A. Kucinskas , V. Dobrovolskas , P. Bonifacio

We employ hydrodynamical simulations to investigate the underlying mechanism responsible for the low levels of gas and dust in globular clusters. Our models examine the competing effects of energy and mass supply from the various components…

Astrophysics of Galaxies · Physics 2019-12-17 J. Naiman , M. Soares-Furtado , E. Ramirez-Ruiz

Using archival {\it Chandra} observations with a total effective exposure of 734 ks, we derive an updated catalog of point sources in the massive globular cluster Terzan 5. Our catalog covers an area of $58.1\, \rm arcmin^{2}$ ($R\leq 4.3…

High Energy Astrophysical Phenomena · Physics 2019-10-02 Zhongqun Cheng , Zhiyuan Li , Taotao Fang , Xiangdong Li , Xiaojie Xu

GRS 1747-312 is a bright transient X-ray source in the globular cluster Terzan 6 with quasi-periodic outbursts approximately every 4.5 months. We carried out 2-60 keV target-of-opportunity observations during eight outbursts with the…

In this paper we derive a bound on the rate of change of the gravitational constant G coming from the pulsating white dwarf G117-B15A. This star is a ZZ Ceti pulsator extensively studied with astroseismological techniques for last three…

Astrophysics · Physics 2009-11-07 Marek Biesiada , Beata Malec

We have used main-sequence fitting to calibrate the distances to the globular clusters NGC 6397, M5, NGC 288, M71 and 47 Tucanae, matching the cluster photometry against data for subdwarfs with precise Hipparcos parallax measurements and…

Astrophysics · Physics 2007-05-23 I. Neill Reid , Palomar Observatory , Caltech

We present rotation period measurements for 107 M dwarfs in the mass range $0.15-0.70 M_\odot$ observed within the context of the APACHE photometric survey. We measure rotation periods in the range 0.5-190 days, with the distribution…

We present spectral and long-timescale variability analyses of \textit{Chandra} ACIS-S observations of the 19 millisecond pulsars (MSPs) with precisely known positions in the globular cluster 47 Tucanae. The X-ray emission of the majority…

White dwarfs in globular clusters offer additional possibilities to determine distances and ages of globular clusters, provided their spectral types and masses are known. We therefore started a project to obtain spectra of white dwarfs in…

Astrophysics · Physics 2009-11-10 S. Moehler , D. Koester , M. Zoccali , F. R. Ferraro , U. Heber , R. Napiwotzki , A. Renzini