TRACING ABUNDANCES IN GALAXIES WITH THE SPITZER ...

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Figure 1.9 Example of PAH features (shaded) in the continuum-subtracted IRS low resolution spectrum of the Bulge planetary nebula PNG000.7+04.7. The PAH features and the strong emission lines are labeled. 27
year lifetime. Spitzer is in an Earth-trailing solar orbit. It has three instruments: the Infrared Array Camera, the Multiband Infrared Photometer, and the Infrared Spectrograph (Werner et al., 2004). This dissertation mainly employs data from the Infrared Spectrograph, and so this instrument is described in more detail below. The Infrared Spectrograph (IRS; Houck et al., 2004) has four different modules covering wavelengths from 5 to 38 µm. It has two low spectral resolution modules (Short-Low (SL) and Long-Low (LL)) with R ≡ λ/∆λ ∼ 90, and it has two high resolution modules (Short-High (SH) and Long-High (LH)) with R ∼ 600. The low resolution modules cover the whole wavelength range of the IRS and are sensitive to the features in the continuum (e.g. crystalline silicate and polycyclic aromatic hydrocarbon (PAH) dust features), while the high resolution modules cover the wavelength range 10–37 µm and are better for studying emission lines. The ob- server may choose to blindly point the telescope with ∼1 ′′ positional accuracy, or choose the PCRS or PeakUp options with 0.4 ′′ positional accuracy. Spectra from Spitzer have the advantage that they are free of atmospheric ab- sorption and the background in space is six orders of magnitude smaller than on Earth, leading to a thousand-fold gain in sensitivity (Houck et al., 2004). Pre- vious infrared telescope missions in space paved the way for Spitzer such as the Infrared Astronomical Satellite (IRAS) and the Infrared Space Observatory (ISO). ISO studied PNe in our Galaxy within a few kpc of the Sun and galactic H II re- gions as well as some extragalactic ones. Due to its more modern detector arrays, Spitzer has greater sensitivity than these previous IR space telescopes. Current Spitzer studies build on this previous work; for example, Chapter 3 of this dissertation presents Spitzer data on eleven PNe in the Bulge of our Galaxy, a region far enough away that it was difficult for ISO to probe the PNe there. Additionally, the Spitzer IRS can do spectral maps, and ISO could not; Chapter 4 employs data 28
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 and 32: (Iion), the radiative transition ra
Page 33 and 34: lines. For example, changing the ad
Page 35 and 36: Figure 1.4 Starburst99 synthetic sp
Page 37 and 38: Figure 1.5 Example of crystalline s
Page 39: H H H H H H H H H Anthanthrene C H
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
Page 89 and 90: 3.5.2 Crystalline Silicates Crystal
Page 91 and 92:
argon, neon, and sulfur tend to be
Page 93 and 94:
Figure 3.2 Continuum subtracted spe
Page 95 and 96:
Figure 3.3 Profiles of PAH features
Page 97 and 98:
mean argon and sulfur abundances ar
Page 99 and 100:
of two smaller than that of Simpson
Page 101 and 102:
towards the Galactic Center. On the
Page 103 and 104:
Table 3.14 Parameters of linear fit
Page 105 and 106:
models that show how a binary compa
Page 107 and 108:
y an outer dense O-rich torus, indi
Page 109 and 110:
CHAPTER 4 ABUNDANCES IN H II REGION
Page 111 and 112:
expect their abundance ratio to rem
Page 113 and 114:
We extract spectra processed throug
Page 115 and 116:
Figure 4.2 IRS spectra of H II regi
Page 117 and 118:
IRS slits from these WIRC observati
Page 119 and 120:
S IV) we employ is equal to Te(O +2
Page 121 and 122:
Figure 4.3 M51 H II region Ne III/N
Page 123 and 124:
Figure 4.4 shows a plot of the (Ne
Page 125 and 126:
James Webb Space Telescope (JWST);
Page 127 and 128:
Bernard-Salas, J. & Tielens, A. G.
Page 129 and 130:
Edgar, R. G., Nordhaus, J., Blackma
Page 131 and 132:
Hummer, D. G., Berrington, K. A., E
Page 133 and 134:
Matsuura, M., Zijlstra, A. A., Mols
Page 135 and 136:
Pradhan, A. K., Montenegro, M., Nah
Page 137:
Vassiliadis, E. & Wood, P. R. 1993,
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