TRACING ABUNDANCES IN GALAXIES WITH THE SPITZER ...

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Table 1.1 Atomic data references. We downloaded data from the IRON Project on 19 October 2006 from TIPbase at: http://vizier.u-strasbg.fr/tipbase/home.html . Energies of the levels are all from Mendoza (1983). Ion Effective Collisional Strength (Ω) Transition Probability (A) Ar + IRON Project Mendoza (1983) Ar ++ IRON Project IRON Project Ar +3 Ramsbottom et al. (1997) Mendoza (1983) Ar +4 IRON Project IRON Project C + Blum & Pradhan (1992) IRON Project & Mendoza (1983) C ++ Berrington (1985) & Mendoza (1983) Berrington et al. (1985) C +3 Mendoza (1983) Mendoza (1983) Mg +4 IRON Project IRON Project N + IRON Project IRON Project & Mendoza (1983) N ++ Blum & Pradhan (1992) Mendoza (1983) N +3 Ramsbottom et al. (1994) Mendoza (1983) N +4 Mendoza (1983) Mendoza (1983) Ne + IRON Project Mendoza (1983) Ne ++ IRON Project IRON Project Ne +3 Mendoza (1983) Mendoza (1983) Ne +4 IRON Project Galavis et al. (1997) O + Pradhan et al. (2006) Mendoza (1983) O ++ IRON Project IRON Project & Mendoza (1983) O +3 IRON Project IRON Project S + Keenan et al. (1996) Mendoza (1983) S ++ IRON Project IRON Project S +3 IRON Project Mendoza (1983) 19
lines. For example, changing the adopted Te from 10000 K to 13000 K for the PN IC 2448 decreases the abundance of Ne ++ derived from the IR [Ne III] line at 15.55 µm by 6% but decreases the abundance of Ne ++ derived from the optical [Ne III] line at 3869 ˚A by 80%. (3) Some ions have lines in the infrared, but not in the optical; for example, infrared spectra show the [Ne II] line which is not observable in the optical, but this ion dominates the total elemental neon abundance in low ionization nebulae. 1.3.4 Ionizing Radiation Field Massive stars and active galactic nuclei produce a hard radiation field (a radiation field which contains a large fraction of highly energetic photons) of high intensity. The hardness of a radiation field gives information about the type of source creating the field. Ratios of IR lines arising from ions which have ionization energies in the ultraviolet indicate the radiation field hardness. For example, it takes 22 eV to create Ne + from neutral neon and 41 eV to create Ne ++ from Ne + , so if the line flux ratio F(Ne III at 15.6µm)/F(Ne II at 12.8 µm) is high, then the ionizing radiation field is hard. Similarly it takes 23 eV to create S ++ from S + and 35 eV to create S +3 from S ++ , so the line flux ratio F(S IV at 10.5 µm)/F(S III at 18.7 µm) also probes the ionizing radiation field. Figure 1.4 shows the ionization energies for these ions overplotted on synthetic spectra for a burst of star formation generated with the code Starburst99 2 . Several factors affect the hardness of the radiation field. Figure 1.4 shows four synthetic spectra: one for each of two abundances (1 and 1/3 solar) and one for each of two times (1 and 10 Myr) after the burst of star formation began. The radiation field is harder, having higher energy photons (to the left in the figure) 2 Starburst99 (Leitherer et al., 1999) is available from the following website: http://www.stsci.edu/science/starburst99/ . 20
Page 1 and 2: TRACING ABUNDANCES IN GALAXIES WITH
Page 3 and 4: TRACING ABUNDANCES IN GALAXIES WITH
Page 5 and 6: BIOGRAPHICAL SKETCH Shannon was bor
Page 7 and 8: ACKNOWLEDGEMENTS First and foremost
Page 9 and 10: thank my husband Ryan. The rest of
Page 11 and 12: 3 Chemical Abundances and Dust in P
Page 13 and 14: LIST OF FIGURES 1.1 Diagram of the
Page 15 and 16: ditionally we find that these nebul
Page 17 and 18: seed nuclei relative to the β deca
Page 19 and 20: shape (Carollo et al., 2007). These
Page 21 and 22: Boltzmann velocity distribution cha
Page 23 and 24: etween recapture and photoionizatio
Page 25 and 26: a whole. Additionally, abundances f
Page 27 and 28: at the appropriate temperature and
Page 29 and 30: (a) 3.37 eV 1.40 eV 0.10 eV 0.04 eV
Page 31: (Iion), the radiative transition ra
Page 35 and 36: Figure 1.4 Starburst99 synthetic sp
Page 37 and 38: Figure 1.5 Example of crystalline s
Page 39 and 40: H H H H H H H H H Anthanthrene C H
Page 41 and 42: year lifetime. Spitzer is in an Ear
Page 43 and 44: CHAPTER 2 THE SPITZER IRS INFRARED
Page 45 and 46: these elements than previous studie
Page 47 and 48: dust is seen in the spectrum. We se
Page 49 and 50: Figure 2.2 Close-ups of emission li
Page 51 and 52: 2.4 Optical and UV Data We compleme
Page 53 and 54: 2.5 Data Analysis Our goal is to ca
Page 55 and 56: 2.5.2 Electron Density We assume an
Page 57 and 58: Table 2.6 Electron temperatures ass
Page 59 and 60: O, N, and C. The helium ionic abund
Page 61 and 62: Barlow (1994) use UV lines for impo
Page 63 and 64: is a spherical nebula with a low ma
Page 65 and 66: CHAPTER 3 CHEMICAL ABUNDANCES AND D
Page 67 and 68: essential data on important ionizat
Page 69 and 70: are members of the Bulge, (Acker et
Page 71 and 72: Table 3.2 Properties of observed GB
Page 73 and 74: nod-averaged line fluxes. Uncertain
Page 75 and 76: Table 3.3 Multiplicative scaling fa
Page 77 and 78: Table 3.4 Observed infrared line fl
Page 79 and 80: 3.5 Data Analysis 3.5.1 Abundances
Page 81 and 82: Table 3.6 Comparison of the derived
Page 83 and 84:
from the most reliable line(s), and
Page 85 and 86:
Table 3.7 Electron temperatures and
Page 87 and 88:
Table 3.9 Ionic abundances Ion x a
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3.5.2 Crystalline Silicates Crystal
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argon, neon, and sulfur tend to be
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Figure 3.2 Continuum subtracted spe
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Figure 3.3 Profiles of PAH features
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mean argon and sulfur abundances ar
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of two smaller than that of Simpson
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towards the Galactic Center. On the
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Table 3.14 Parameters of linear fit
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models that show how a binary compa
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y an outer dense O-rich torus, indi
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CHAPTER 4 ABUNDANCES IN H II REGION
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expect their abundance ratio to rem
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We extract spectra processed throug
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Figure 4.2 IRS spectra of H II regi
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IRS slits from these WIRC observati
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S IV) we employ is equal to Te(O +2
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Figure 4.3 M51 H II region Ne III/N
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Figure 4.4 shows a plot of the (Ne
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James Webb Space Telescope (JWST);
Page 127 and 128:
Bernard-Salas, J. & Tielens, A. G.
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Edgar, R. G., Nordhaus, J., Blackma
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Hummer, D. G., Berrington, K. A., E
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Matsuura, M., Zijlstra, A. A., Mols
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Pradhan, A. K., Montenegro, M., Nah
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Vassiliadis, E. & Wood, P. R. 1993,
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