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Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Zach Gazak Rolf Kudritzki (chair), Josh Barnes, Fabio Bresolin, Ben Davies, Lisa Kewley, John Learned, John Rayner
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Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Rogelio Bernal Andreo (DeepSkyColors.com) α Orionis (Betelgeuse)
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Metallicity gradients of star forming galaxies: Extragalactic Chemical Abundances Key targets for understanding galaxy formation and evolution Important input for modeling galaxy evolution Mass - Metallicity and Mass - Gradient relationship M31 Jerry Lodriguss M33 Ken Crawford M33 Ken Crawford M81 Giovanni Benintende NGC 2403 Subaru
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Metallicity gradients of star forming galaxies: Extragalactic Chemical Abundances M33 Ken Crawford Typically measured using highly uncertain “strong line” methods of collisional lines in H II regions: Problems with these methods include: I. Troublesome calibration II. Abundance discrepancies III. Line saturation degeneracies
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Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO)
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Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO) Bresolin et al. 2009
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Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO) Kewley & Ellison 2008
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Collisional metallicities 0.2 to 0.4 dex lower than recombination measurements. II: Abundance Discrepancy Factor Simon-Diaz & Stasinska 2010 Dust composition
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Collisional metallicities 0.2 to 0.4 dex lower than recombination measurements. II: Abundance Discrepancy Factor Simon-Diaz & Stasinska 2010 Peimbert et al. 2006 Dust composition
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Degeneracy at over ~0.5 solar metallicity III: Line Saturation Stasinska 2010 [OIII] and [NII][NII] only
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Significant Discrepancies Stasinska 2010 [OIII] and [NII] [NII] only Simon-Diaz & Stasinska 2010 M33: U et al. 2009 A and B Supergiants
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Significant Discrepancies Stasinska 2010 [OIII] and [NII] [NII] only Simon-Diaz & Stasinska 2010 M33: U et al. 2009 A and B Supergiants + HII Regions
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Stars drive chemical enrichment Evolution of galaxies Abundance pattern gradients Interstellar extinction Distances Quantitative Spectroscopy of Stars
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8 < M init < 35 M sun Red Supergiants B8-A4 K–M M J -8 to -11
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Cool: T eff < 4500 K Inflated: R on AU scales Convection + Mass Loss Red Supergiants ESO Betelgeuse ESO & P. Kervella
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Historically, high resolution (R~20,000) required. Unrealistic extragalactic integration times! Davies, Kudritzki & Figer 2010: We can use R~3000 in J band, log[Z] to 0.1 dex Spectroscopy of RSGs
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Peak RSG flux and strong, well separated lines RSGs in the J Band 3500 K J band
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Peak RSG flux and strong, well separated lines RSGs in the J Band 3500 K J band R~2500 SpeX (Rayner et al. 2009) HD 39801
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MARCS model grid: Spherical symmetry, LTE RSGs in the J Band R~2500 SpeX (Rayner et al. 2009) HD 39801
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MARCS model grid: Spherical symmetry, LTE RSGs in the J Band R~2500 SpeX (Rayner et al. 2009) HD 39801 Teff: 3750 +/- 220 (3710) log[Z]: 0.16 +/- 0.28 (0.19 +/- 0.21)
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Finding RSGs Image Courtesy of Mike Bessell LMC Ben Davies
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M33
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Thesis work: I. The Milky Way II. Local Group Galaxies III. Beyond the Local Group Solar metallicity Perseus OB1 RSGs M31 (Milky Way analog) M33 (sub-solar metallicities) M81 (super solar metallicities) NGC2403 (sub-solar metallicities) Super Star Clusters (SSCs)
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I. Solar Neighborhood: Per OB-1 20+ RSGs
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I. Solar Neighborhood: Per OB-1 Observe full RSG population at high and low resolution Compare and calibrate high-R v. low-R methods Calibrate to well established BSG techniques J, H at R~20,000: IRCS on Subaru (1 night) R~ 2,500: SpeX on IRTF (1 night) MARCS model grid Develop analysis techniques Collaborate with Urbaneja, Kudritzki: spectra of all known BSGs in Per OB1
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I. Solar Neighborhood: Per OB-1 Critical dataset for this work and into the future Test and calibrate new future RSG atmosphere codes
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II. Galactic Neighborhood: M31, M33 M31 Jerry Lodriguss M33 Ken Crawford Metallicity gradients of Local Group galaxies using RSGs
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Milky Way analog Very little spectroscopic information over the radial gradient. 1000s of RSGs II. Galactic Neighborhood: M31, M33 M31 Jerry Lodriguss 2 nights with MOSFIRE on Keck I: Full coverage of radial metallicity gradient with detailed information on α/Fe element ratios.
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II. Galactic Neighborhood: M31, M33 M33 Ken Crawford 1 night with MOSFIRE on Keck I: Cover radial gradient with brightest RSGs, allowing a critical test of conflicting results between HII and BSGs. M33: U et al. 2009 A and B Supergiants + HII Regions
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Abundance gradient of M81 or NGC 2403 III: Beyond the Local Group M81 Giovanni Benintende NGC 2403 Subaru
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III: Beyond the Local Group M81 Giovanni Benintende 4 Mpc Indications of super-solar central metallicity and shallow gradient 1000s of RSGs 3 nights with MOSFIRE on Keck I: Mass-metallicity relationship from RSGs (with LG work) Spiral galaxy metallicity gradients independent of mass if considered on a dimensionless length scale?
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10 5 M sun with ~100 RSGs: reach 10x distances IIIb: Super Star Clusters M82: McCrady & Graham 2007
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10 5 M sun with ~100 RSGs: reach 10x distances IIIb: Super Star Clusters Perseus OB1 work will allow a critical test Proceed with additional observations if successful Promising agreement with M51 SSC photometry from Nate Bastian
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RSGs with Extremely Large Telescopes Evans et al. 2010 Limiting m J ~23 means RSGs beyond Virgo Cluster
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RSGs with Extremely Large Telescopes Evans et al. 2010 Limiting m J ~23 means RSGs beyond Virgo Cluster
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RSGs with Extremely Large Telescopes Excellent recovery of metallicity (Evans et al. 2010)
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Center of Virgo Cluster Gunter Kerschhuber
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Thesis Timeline MOSFIRE backup instrument is FMOS on Subaru
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