Judy’s contribution to globular cluster science Raffaele Gratton INAF – Osservatorio Astronomico di Padova, ITALY

Contribution to GC science: numbers 139 entries in ADS with "Cohen, J." AND "globular“: oldest 1975, most recent 2016 (query on Jan. 11, 2017) 93 refereed papers 49 as first author 6400 citations About 60% of Judy’s production

Judy’s most cited papers on GCs 292 cit: Cohen, J. G.; Persson, S. E.; Frogel, J. A. Infrared photometry, bolometric magnitudes, and effective temperatures for giants in M3, M13, M92, and M67, 1978 ApJ, 222, 165 235 cit: Frogel, J. A.; Cohen, J. G.; Persson, S. E. Globular cluster giant branches and the metallicity scale, 1983 ApJ, 275, 773 219 cit: Cohen, J. G. Abundances in globular cluster red giants. I - M3 and M13, 1978 ApJ, 223, 487 216 cit: Frogel, J. A.; Persson, S. E.; Cohen, J. G. Infrared photometry of red giants in the globular cluster 47 Tucanae, 1981 ApJ, 246, 842 214 cit: Persson, S. E.; Aaronson, M.; Cohen, J. G.; Frogel, J. A.; Matthews, K. Photometric studies of composite stellar systems. V - Infrared photometry of star clusters in the Magellanic clouds, 1983 ApJ, 266, 105 211 cit: Frogel, J. A.; Persson, S. E.; Cohen, J. G. Infrared photometry, bolometric luminosities, and effective temperatures for giant stars in 26 globular clusters, 1983 ApJS, 53, 713 186 cit: Aaronson, M.; Cohen, J. G.; Mould, J.; Malkan, M. Calibration of metallicity effects on the integrated colors of globular clusters and early-type galaxies, 1978 ApJ, 223, 824 165 cit: Cohen, J. G.; Blakeslee, J. P.; Ryzhov, A. The Ages and Abundances of a Large Sample of M87 Globular Clusters, 1998 ApJ, 496, 808 164 cit: Ramírez, S.V.; Cohen, J.G. Abundances in Stars from the Red Giant Branch Tip to Near the Main-Sequence Turnoff in M71. III. Abundance Ratios, 2002 AJ 123, 3277 157 cit: Cohen, J.G.; Meléndez, J. Abundances in a Large Sample of Stars in M3 and M13, 2005, AJ, 129, 303

Near IR photometry of individual stars in GCs and integrated photometry of clusters Very strong 1978-1984, 16 papers; 1994-1995: 2 papers; 2007: 1 paper Long term collaboration with Frogel and Persson First derivation of near-IR photometry (JHK+CO) for individual GCs stars Very useful for accurate determination of the physical parameters of the stars Spread in the CO abundances in ω Cen

High resolution spectroscopy of GC stars - photographic Echelle spectra Strong production 1976-1983: 6 papers First attempt to derive abundances from high resolution spectra of GC stars since the pioneering work by Helfer, Wallerstein and Greeenstein (1959): First extensive survey at high spectral resolution of GC giants Used the new echelle spectrographs at KPNO and CTIO, equipped with image tubes Confirmation of the metallicity scale for metal-poor clusters Overabundance of alpha-elements First indication of a spread in Na and O abundances!! Observation of a large spread in ω Cen (confirming photometric and ΔS results) Some problem with the most metal-rich clusters (very low abundances)

Abundances for GC stars down to MS - CCD spectra 1986/1991: 2 papers; strong production 1999-2005: 17 papers; 2009-2016: 7 papers Mainly using HIRES at Keck Among the first abundance analysis of MS stars in GCs (with Solange Ramirez)  strong support to the multiple population scenario Important results on the spread in the abundances of p-capture elements: the spread in dwarfs is similar to that observed in giants  indication that it likely involves the whole star  support to a multiple-generation scenario(with Michael Briley and Peter Stetson) More recently: Large K-Ca anti-correlation within NGC2419 stars (p-capture at extremely high T) (with Evan Kirby) First abundances from high resolution spectroscopy for metal-rich bulge clusters (NGC6553 and NGC6528)

HB, and peculiar stars in GCs 1984-1989: 4 papers; strong production 1997-2000: 4 papers, mainly with Behr Very important contribution on the composition and rotation of HB stars Evidence of the importance of the Grundahl jump (on/off sedimentation and radiative levitation vs rotation)

Dynamics and abundances of GCs in other galaxies A few papers 1983-1991; strong production 1997-2009: 13 papers; 1 paper in 2014 Long term interest On the abundance side, contribution (with Janet Colucci) to the development of techniques to derive abundances from integrated spectra of clusters

Others Distances, Ages, and cmd of globular clusters: A few papers 1982- 1992 Interstellar lines in the spectra of the globular clusters

Conclusion THANKS, JUDY Since many years, Judy is a reference person in GC science She obtained several basic reference results: First extensive survey at high spectral resolution of GC giants First indication of a spread in Na and O abundances Among the first abundance analysis of MS stars in GCs (with Solange Ramirez)  strong support to the multiple population scenario The spread in the abundances of p-capture elements in dwarfs is similar to that observed in giants  indication that it likely involves the whole star  support to a multiple-generation scenario (with Michael Briley and Peter Stetson) Large K-Ca anti-correlation within NGC2419 stars (p-capture at extremely high T) (with Evan Kirby) Evidence of the importance of the Grundahl jump (on/off sedimentation and radiative levitation vs rotation) (with Bertrand Behr) Contribution to the development of techniques to derive abundances from integrated spectra of clusters (with Janet Colucci) A real fundamental work!!! THANKS, JUDY

Judy’s career: papers (ADS)

Judy’s career: citations (ADS)