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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.

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Presentation on theme: "Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Zach Gazak Rolf Kudritzki (chair), Josh Barnes, Fabio Bresolin, Ben."— Presentation transcript:

1 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

2 Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Rogelio Bernal Andreo (DeepSkyColors.com) α Orionis (Betelgeuse)

3 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

4 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

5 Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO)

6 Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO) Bresolin et al. 2009

7 Collisional line methods from H II regions I: Troublesome Calibration Results depend heavily on choice of calibration NGC 300 (ESO) Kewley & Ellison 2008

8 Collisional metallicities 0.2 to 0.4 dex lower than recombination measurements. II: Abundance Discrepancy Factor Simon-Diaz & Stasinska 2010 Dust composition

9 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

10 Degeneracy at over ~0.5 solar metallicity III: Line Saturation Stasinska 2010 [OIII] and [NII][NII] only

11 Significant Discrepancies Stasinska 2010 [OIII] and [NII] [NII] only Simon-Diaz & Stasinska 2010 M33: U et al. 2009 A and B Supergiants

12 Significant Discrepancies Stasinska 2010 [OIII] and [NII] [NII] only Simon-Diaz & Stasinska 2010 M33: U et al. 2009 A and B Supergiants + HII Regions

13 Stars drive chemical enrichment Evolution of galaxies Abundance pattern gradients Interstellar extinction Distances Quantitative Spectroscopy of Stars

14 8 < M init < 35 M sun Red Supergiants B8-A4 K–M M J -8 to -11

15 Cool: T eff < 4500 K Inflated: R on AU scales Convection + Mass Loss Red Supergiants ESO Betelgeuse ESO & P. Kervella

16 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

17 Peak RSG flux and strong, well separated lines RSGs in the J Band 3500 K J band

18 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

19 MARCS model grid: Spherical symmetry, LTE RSGs in the J Band R~2500 SpeX (Rayner et al. 2009) HD 39801

20 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)

21 Finding RSGs Image Courtesy of Mike Bessell LMC Ben Davies

22 M33

23

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26 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)

27 I. Solar Neighborhood: Per OB-1 20+ RSGs

28 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

29 I. Solar Neighborhood: Per OB-1 Critical dataset for this work and into the future Test and calibrate new future RSG atmosphere codes

30 II. Galactic Neighborhood: M31, M33 M31 Jerry Lodriguss M33 Ken Crawford Metallicity gradients of Local Group galaxies using RSGs

31 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.

32 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

33 Abundance gradient of M81 or NGC 2403 III: Beyond the Local Group M81 Giovanni Benintende NGC 2403 Subaru

34 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?

35 10 5 M sun with ~100 RSGs: reach 10x distances IIIb: Super Star Clusters M82: McCrady & Graham 2007

36 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

37 RSGs with Extremely Large Telescopes Evans et al. 2010 Limiting m J ~23 means RSGs beyond Virgo Cluster

38 RSGs with Extremely Large Telescopes Evans et al. 2010 Limiting m J ~23 means RSGs beyond Virgo Cluster

39 RSGs with Extremely Large Telescopes Excellent recovery of metallicity (Evans et al. 2010)

40 Center of Virgo Cluster Gunter Kerschhuber

41 Thesis Timeline MOSFIRE backup instrument is FMOS on Subaru


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