Forward and Back: Kinematics of the Palomar 5 Tidal Tails

P B Kuzma*, A M N Ferguson, A L Varri, M J Irwin, E J Bernard, E Tolstoy, J Peñarrubia, D B Zucker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The tidal tails of Palomar 5 (Pal 5) have been the focus of many spectroscopic studies in an attempt to identify individual stars lying along the stream and characterise their kinematics. The well-studied trailing tail has been explored out to a distance of 15○ from the cluster centre, while less than four degrees have been examined along the leading tail. In this paper, we present results of a spectroscopic study of two fields along the leading tail that we have observed with the AAOmega spectrograph on the Anglo-Australian telescope. One of these fields lies roughly 7○ along the leading tail, beyond what has been previously been explored spectroscopically. Combining our measurements of kinematics and line strengths with Pan-STARRS1 photometric data and Gaia EDR3 astrometry, we adopt a probabilistic approach to identify 16 stars with high probability of belonging to the Pal 5 stream. Eight of these stars lie in the outermost field and their sky positions confirm the presence of ‘fanning’ in the leading arm. We also revisit previously-published radial velocity studies and incorporate Gaia EDR3 astrometry to remove interloping field stars. With a final sample of 109 bona fide Pal 5 cluster and tidal stream stars, we characterise the 3D kinematics along the the full extent of the system. We provide this catalogue for future modeling work.
Original languageEnglish
Pages (from-to)315-327
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date14 Feb 2022
Publication statusPublished - 1 May 2022

Keywords / Materials (for Non-textual outputs)

  • globular clusters: general
  • globular clusters: individual: Palomar 5
  • stars: abundances
  • stars: kinematics and dynamics


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