1 / 17

Jason Kalirai (UC Santa Cruz)

Stellar Remnants as Astrophysical Probes. March 11 th , 2008. Hubble Fellows Symp. 2008 -- STScI. Jason Kalirai (UC Santa Cruz). Collaborators: UMontreal - P. Bergeron UCLA - B. Hansen, D. Reitzel, R. M. Rich OCIW - D. Kelson UBC - H. Richer …also for NGC 6397 project:

ilar
Download Presentation

Jason Kalirai (UC Santa Cruz)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Jason Kalirai (UC Santa Cruz) Collaborators: UMontreal - P. Bergeron UCLA - B. Hansen, D. Reitzel, R. M. Rich OCIW - D. Kelson UBC - H. Richer …also for NGC 6397 project: Jay Anderson (STScI), Ivan King (UW) James Brewer and Saul Davis (UBC) Gregory Fahlman and Peter Stetson (HIA/NRC) Michael Shara (AMNH) Jarrod Hurley (Swinburne)

  2. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Outline: 1.) A new imaging survey for white dwarfs: The CFHT Open Cluster Survey. 2.) The initial-final mass relation. chemical evolution and enrichment of the ISM the age of the Galactic halo: HST studies of globular clusters the age of the Galactic disk 3.) Stellar mass loss as a function of environment. UV upturn in elliptical galaxies planets around white dwarfs

  3. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI The CFHT Open Star Cluster Survey (Kalirai et al. 2001, AJ, 122, 257) - Deep CFHT B,V imaging data set of two dozen, rich open clusters. Goals: 1.) Cluster ages, distances, reddening, richness, etc. 2.) Luminosity and mass functions. 3.) Test theoretical isochrones through numerical simulations. 4.) Catalogue large populations of white dwarfs in each system. Results - NGC 6819: Kalirai et al. (2001, AJ, 122, 267) - NGC 2099: Kalirai et al. (2001, AJ, 122, 3239) - NGC 2168 and NGC 2323: Kalirai et al. (2003, AJ, 126, 1402) - Numerical Simulations: Kalirai & Tosi (2004, MNRAS, 351, 649) - NGC 6791: Kalirai et al. (2007, ApJ, 671, 748) - NGC 7789: Kalirai et al. (2007, ApJ, in press, astro-ph/0706.3894) - data shared with many external groups…

  4. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI NGC 6819 Synthetic CMD Some Results Age = 2.2 +/- 0.2 Gyr E(B-V) = 0.12 (m-M)o = 12.20 Z = 0.02 Overshooting required 20-30% binaries Mtot = 4 X 103 Msun Inconsistent lower MS Kalirai & Tosi (2004, MNRAS, 351, 649)

  5. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Some CFHT CMDs

  6. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Kalirai et al. (2008, ApJ, 676, 594)

  7. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Kalirai et al. (2008, ApJ, 676, 594)

  8. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Kalirai et al. (2008, ApJ, 676, 594) Weidemann + Reimers & Koester (1980’s) Claver et al. (2001) Dobbie et al. (2004, 2006) Williams et al. (2004, 2007) Kalirai et al. (2005) Liebert et al. (2005) Kalirai et al. (2008, ApJ, 676, 594)

  9. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI The Age of the MW Halo NGC 6397 126 HST/ACS orbits Kalirai et al. (2007, ApJL, 657, 93) Richer et al. (2006, Science, 313, 936) Hansen et al. (2007, ApJ, 671, 380)

  10. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI The Age of the MW Halo NGC 6397 126 HST/ACS orbits tNGC 6397 = 11.5 - 12.0 Gyrs tM4 = 10.1 - 12.5 Gyrs t47 Tuc = ??? Hansen et al. (2007, ApJ, 671, 380)

  11. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI A Strange Cluster (N6791): Age = 8 -10 Gyrs but… [Fe/H] = +0.4 Kalirai et al. (2007, ApJ, 671, 748)

  12. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI MS turnoff age = 8 Gyrs WD cooling age = 2.4 Gyrs? Bedin et al. (2005, ApJL, 624, 45)

  13. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI The Theory: - Mass Loss on the RGB (Faulkner 1972; Sweigart 1987, Castellani & Castellani 1993; Hansen 2005). Two Tests: 1.) RGB luminosity function. 2.) WD mass function. Kalirai et al. (2007, ApJ, 671, 748)

  14. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Forming He-core White Dwarfs Kalirai et al. (2007, ApJ, 671, 748)

  15. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Forming He-core White Dwarfs Bedin et al. (2008, ApJ, in press, astro-ph/0801.1346)

  16. March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI Conclusions Summary: age/distance/reddening/binary fraction/etc. measured for a large sample. Mfinal = (0.109 +/- 0.007)Minitial + (0.394 +/- 0.025) Msun. Age of globular cluster NGC 6397 = 11.5 - 12.0 Gyr Age of globular cluster NGC 6121 = 10.1 - 12.5 Gyr Age of Galactic disk = 8 Gyr Mass loss is more efficient in higher metallicity environments. Implications: UV upturn in E’s planets around WDs

  17. Stellar Remnants as Astrophysical Probes March 11th, 2008 Hubble Fellows Symp. 2008 -- STScI The Age of the MW Disk White dwarf mass function: Liebert, Bergeron & Holberg (2005)

More Related