Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Zach Gazak Rolf...
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Transcript of Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique Zach Gazak Rolf...
Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band TechniqueZach Gazak
Rolf Kudritzki (chair), Josh Barnes, Fabio Bresolin, Ben Davies, Lisa Kewley, John Learned, John Rayner
Red Supergiants as Extragalactic Abundance Probes: Establishing the J-Band Technique
Rogelio Bernal Andreo (DeepSkyColors.com)
α Orionis (Betelgeuse)
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
Ken Crawford
M33
M81
Giovanni Benintende
NGC 2403
Subaru
Metallicity gradients of star forming galaxies:
Extragalactic Chemical Abundances
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
Collisional line methods from H II regions
I: Troublesome Calibration
Results depend heavily on choice of calibrationNGC 300 (ESO)
Collisional line methods from H II regions
I: Troublesome Calibration
Results depend heavily on choice of calibrationNGC 300 (ESO)
Bresolin et al. 2009
Collisional line methods from H II regions
I: Troublesome Calibration
Results depend heavily on choice of calibrationNGC 300 (ESO)
Kewley & Ellison 2008
Collisional metallicities 0.2 to 0.4 dex lower than recombination measurements.
II: Abundance Discrepancy Factor
Simon-Diaz & Stasinska 2010
Dust composition
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
Degeneracy at over ~0.5 solar metallicity
III: Line Saturation
Stasinska 2010
[OIII] and [NII] [NII] only
Significant Discrepancies
Stasinska 2010
[OIII] and [NII] [NII] only
Simon-Diaz & Stasinska 2010
M33: U et al. 2009A and B Supergiants
Significant Discrepancies
Stasinska 2010
[OIII] and [NII] [NII] only
Simon-Diaz & Stasinska 2010
M33: U et al. 2009A and B Supergiants
+ HII Regions
Stars drive chemical enrichment
Evolution of galaxies
Abundance pattern gradients
Interstellar extinction
Distances
Quantitative Spectroscopy of Stars
8 < Minit < 35 Msun
Red Supergiants
B8-A4
K–M
MJ -8 to -11
Cool: Teff < 4500 K
Inflated: R on AU scales
Convection + Mass Loss
Red Supergiants
ESO
Betelgeuse
ESO & P. Kervella
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
Peak RSG flux and strong, well separated linesRSGs in the J Band
3500 K
J band
Peak RSG flux and strong, well separated linesRSGs in the J Band
3500 K
J band
R~2500 SpeX (Rayner et al. 2009)
HD 39801
MARCS model grid: Spherical symmetry, LTERSGs in the J Band
R~2500 SpeX (Rayner et al. 2009)
HD 39801
MARCS model grid: Spherical symmetry, LTERSGs 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)
Finding RSGs
Image Courtesy of Mike Bessell
LMC
Ben Davies
M33
M33
M33
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)
I. Solar Neighborhood: Per OB-1
20+ RSGs
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 gridDevelop analysis techniques
Collaborate with Urbaneja, Kudritzki: spectra of all known BSGs in Per OB1
I. Solar Neighborhood: Per OB-1
Critical dataset for this work and into the future
Test and calibrate new future RSG atmosphere codes
II. Galactic Neighborhood: M31, M33
M31
Jerry Lodriguss
M33
Ken Crawford
Metallicity gradients of Local Group
galaxies using RSGs
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.
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. 2009A and B
Supergiants
+ HII Regions
Abundance gradient of M81 or NGC 2403
III: Beyond the Local Group
M81
Giovanni Benintende
NGC 2403
Subaru
III: Beyond the Local GroupM81
Giovanni Benintende
4 Mpc
Indications of super-solar central metallicity and shallow gradient
1000s of RSGs3 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?
105 Msun with ~100 RSGs: reach 10x distances
IIIb: Super Star Clusters
M82: McCrady & Graham 2007
105 Msun with ~100 RSGs: reach 10x distances
IIIb: Super Star Clusters
Perseus OB1 work will allow a critical testProceed with additional observations if successful
Promising agreement with M51 SSC photometry from Nate Bastian
RSGs with Extremely Large Telescopes
Evans et al. 2010
Limiting mJ ~23 means RSGs beyond Virgo Cluster
RSGs with Extremely Large Telescopes
Evans et al. 2010
Limiting mJ ~23 means RSGs beyond Virgo Cluster
RSGs with Extremely Large Telescopes
Excellent recovery of metallicity (Evans et al. 2010)
Center of Virgo Cluster Gunter Kerschhuber
Thesis Timeline
MOSFIRE backup instrument is FMOS on Subaru