TRACING ABUNDANCES IN GALAXIES WITH THE SPITZER ...

More documents

Recommendations

Info

extracted area along with the added uncertainty from adopting an extinction from a different sized aperture. We did find that in the extranuclear H II regions, the hardness of the radiation field as traced by the Ne III/Ne II flux ratio increases as the distance from the galactic center increases (attributed to decreasing abundance and/or stellar age with increasing distance). Additionally, we found that the neon to sulfur ratio as traced by (Ne + +Ne ++ )/(S ++ +S 3+ ) appears to decrease with increasing distance from the nucleus, but this probably does not reflect a trend in the true Ne/S ratio, but rather reflects the affect of not accounting for unobserved S + and/or depletion of sulfur onto dust. In order to determine accurate Ne/H and S/H abundances from Spitzer IRS spectra, it is necessary to measure the hydrogen within the IRS slit. The short integration time of the S<strong>IN</strong>GS maps (1 minute at each pointing with a maximum integration time of 4 minutes at the center of the maps where the pointings overlap) is not long enough to detect the H I(7-6) line in the SH module of the Spitzer IRS. However, longer integration times of ∼15+ minutes do allow the detection of this line in H II regions of external galaxies. For example, the program by Robert Rubin (program ID 20057) makes small maps of H II regions in M33 with a maximum integration time in the centers of the maps of 18 minutes, and they detect the H I(7-6) line, usually above the 3σ limit (private communication). A program by Fabio Bresolin (program ID 30205) does staring mode observations of ten H II regions in nearby galaxies with a 26 minute integration time on each region, and they should also detect the H I(7-6) line. Programs such as Rubin’s and Bresolin’s with integration times long enough to detect the H I(7-6) line are the way to determine accurate neon and sulfur abundances from infrared spectra of H II regions across galaxies. Future investigators will be able to determine abundances from infrared lines with the Mid-Infrared Instrument (MIRI) on the 111
James Webb Space Telescope (JWST); MIRI will provide high resolution (R ∼ 3000) spectroscopy from 5 to 28 µm and thus cover the H I(7-6) at 12.37 µm as well as lines from important ionization stages of argon, neon, and sulfur. 112
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 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
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: Figure 4.4 shows a plot of the (Ne
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,
show all

TRACING ABUNDANCES IN GALAXIES WITH THE SPITZER ...

Create successful ePaper yourself

Delete template?

Save as template?