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We present internal velocity dispersions and precise radial velocities for 200 globular clusters (GCs) in M31 that are derived using new high-resolution spectra from MMT/Hectochelle. Of these, 163 also have King model structural parameters…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Jay Strader , Nelson Caldwell , Anil Seth

We report the discovery of significant stellar substructure in the halo and outer disk of our nearest large galactic neighbour, M31. Our deep panoramic survey with the Isaac Newton Telescope Wide Field Camera currently maps out an area of…

Astrophysics · Physics 2011-03-10 Annette Ferguson , Mike Irwin , Rodrigo Ibata , Geraint Lewis , Nial Tanvir

We present the results of deep I and V-band photometry of the halo stars near the southeast minor axis of the Local Group spiral galaxy M33. An (I,V-I) color-magnitude diagram distinctly reveals the red giant branch stars at the bright end…

Astrophysics · Physics 2009-11-10 R. Scott Brooks , Christine D. Wilson , William E. Harris

In this paper, we present low resolution (R=500) near-infrared spectra for selected and serendipitous sources in six inner in-plane Galactic fields, with the aim of analysing the stellar content present. From the equivalent widths of the…

Astrophysics · Physics 2009-11-13 C. González-Fernández , A. Cabrera-Lavers , P. L. Hammersley , F. Garzón

We present a high precision photometric view of the stellar populations in the outer halo of M31, using data taken with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). We analyse the field populations adjacent to 11…

Stars in massive star clusters exhibit intrinsic variations in some light elements (MPs) that are difficult to explain in a coherent formation scenario. In recent years, HST photometry has led to the characterisation of the global…

Astrophysics of Galaxies · Physics 2022-06-29 Carmela Lardo , Maurizio Salaris , Santi Cassisi , Nate Bastian

(Abridged) We performed the spectroscopic observations of 11 confirmed GCs in M31 with the Xinglong 2.16m telescope and we mainly focus on the fits method and the metallicity gradient for the M31 GC sample. We analyzed and discussed more…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Zhou Fan , Ya-Fang Huang , Jin-Zeng Li , Xu Zhou , Jun Ma , Yong-Heng Zhao

An open issue about multiple stellar populations in globular clusters (GCs) is the possible existence of metallicity spreads in first generation (FG) stars. Recent estimates based on HST pseudo-colours map (PCM) derived unlikely large…

Astrophysics of Galaxies · Physics 2025-04-16 Eugenio Carretta , Angela Bragaglia

In this paper, we presented metal abundance properties of 144 M81 globular clusters. These globulars consist of the largest globular cluster sample in M81 till now. Our main results are: the distribution of metallicities are bimodal, with…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jun Ma , Zhenyu Wu , Tianmeng Zhang , Song Wang , Zhou Fan , Jianghua Wu , Hu Zou , Cuihua Du , Xu Zhou , Qirong Yuan

We present the metallicity distribution of red giant branch (RGB) stars in M31's stellar halo, derived from photometric metallicity estimates for over 1500 spectroscopically confirmed RGB halo stars. The stellar sample comes from 38 halo…

We present Keck/HIRES spectra of 3 globular clusters in the outer halo of M31, at projected distances beyond ~80 kpc from M31. The measured recession velocities for all 3 globular clusters confirm their association with the globular cluster…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 A. Alves-Brito , D. A. Forbes , J. T. Mendel , G. K. T. Hau , M. T. Murphy

We present deep CCD photometry in the VI passbands using the WIYN 3.5m telescope of a field located approximately 20' southeast of the center of M33; this field includes the region studied by Mould & Kristian in their 1986 paper. The…

Astrophysics · Physics 2009-11-10 Glenn P. Tiede , Ata Sarajedini , Michael K. Barker

We collected a sample of 100 galaxies for which different observers have determined colour indices of globular cluster candidates. The sample includes representatives of galaxies of various morphological types and different luminosities.…

Astrophysics · Physics 2007-05-23 Helina Eerik , Peeter Tenjes

We present new high signal-to-noise spectroscopic data on the M31 globular cluster system, obtained with the Hectospec multifiber spectrograph on the 6.5m MMT. More than 300 clusters have been observed at a resolution of 5A. The primary…

Astrophysics of Galaxies · Physics 2015-05-27 Nelson Caldwell , Ricardo Schiavon , Heather Morrison , James A. Rose , Paul Harding

With the ultimate aim of distinguishing between various models describing the formation of galaxy halos (e.g. radial or multi-phase collapse, random mergers), we have completed a spectroscopic study of the globular cluster system of M31. We…

We have applied the MCS image deconvolution algorithm (Magain, Courbin & Sohy 1998) to HST/WFPC2 V, I data of three M31 bulge globular clusters (G170, G177, and G198) and control fields near each cluster. All three clusters are clearly…

Astrophysics · Physics 2007-05-23 P. Jablonka , F. Courbin , G. Meylan , A. Sarajedini , T. J. Bridges , P. Magain

We have carried out spectrophotometry in the range 3600--9700\AA~ of five globular clusters in NGC 5128 for which previous photometric studies suggested a high metal content. We compare the equivalent widths of a set of metallic features of…

Astrophysics · Physics 2007-05-23 Jablonka , Bica , Pelat , Alloin

We have collected spectra of about 2000 red giant branch (RGB) stars in 19 Galactic globular clusters (GC) using FLAMES@VLT (about 100 star with GIRAFFE and about 10 with UVES, respectively, in each GC). These observations provide an…

Astrophysics of Galaxies · Physics 2015-05-14 Eugenio Carretta , Angela Bragaglia , Raffaele Gratton , Valentina D'Orazi , Sara Lucatello

NGC 3201 is a globular cluster suspected to have an intrinsic spread in the iron content. We re-analysed a sample of 21 cluster stars observed with UVES-FLAMES at the Very Large Telescope and for which Simmerer et al. found a 0.4 dex wide…

Solar and Stellar Astrophysics · Physics 2015-06-23 A. Mucciarelli , E. Lapenna , D. Massari , F. R. Ferraro , B. Lanzoni

(Abridged version) Mayall II = G1 is one of the brightest globular clusters belonging to M31, the Andromeda galaxy. Our observations with HST/WFPC2 provide data for the (I vs. V-I) and (V vs. V-I) color-magnitude diagrams. From model…

Astrophysics · Physics 2009-11-06 G. Meylan , A. Sarajedini , P. Jablonka , S. G. Djorgovski , T. Bridges , R. M. Rich