2000ApJS..128..511O


Query : 2000ApJS..128..511O

2000ApJS..128..511O - Astrophys. J., Suppl. Ser., 128, 511-548 (2000/June-0)

Calibration of nebular emission-line diagnostics. I. Stellar effective temperatures.

OEY M.S., DOPITA M.A., SHIELDS J.C. and SMITH R.C.

Abstract (from CDS):

We present a detailed comparison of optical H II region spectra to photoionization models based on modern stellar atmosphere models. We examine both spatially resolved and integrated emission-line spectra of the H II regions DEM L323, DEM L243, DEM L199, and DEM L301 in the Large Magellanic Cloud. The published spectral classifications of the dominant stars range from O7 to WN3, and morphologies range from Strömgren sphere to shell structure. Two of the objects include SNR contamination. The overall agreement with the predictions is generally within 0.2 dex for major diagnostic line ratios. An apparent pattern in the remaining discrepancies is that the predicted electron temperature is ∼1000 K hotter than observed. [Ne III] intensities are also slightly overpredicted, which may or may not be related. We model the shock emission for the SNR-contaminated objects and find excellent agreement with the observations for composite shock and photoionized spectra. DEM L301's emission apparently results from both shocks and density-bounded photoionization. The existence of contaminating shocks can be difficult to ascertain in the spatially integrated spectra. Our analysis of the complex DEM L199 allows a nebular emission-line test of unprecedented detail for WR atmospheres. Surprisingly, we find no nebular He II λ4686 emission, despite the fact that both of the dominant WN3 stars should be hot enough to fully ionize He I in their atmospheres. The nebular diagnostics are again in excellent agreement with the data, for stellar models not producing He+-ionizing photons. The optical diagnostics are furthermore quite insensitive to the ionizing energy distribution for these early WR stars. We confirm that the η' emission-line parameter is not as useful as hoped for determining the ionizing stellar effective temperature, T*. Both empirically and theoretically, we find that it is insensitive for T*≳40 kK and that it also varies spatially. The shock-contaminated objects show that η' will also yield a spuriously high T* in the presence of shocks. It is furthermore sensitive to shell morphology. We suggest [Ne III]/Hβ as an additional probe of T*. Although it is abundance dependent, [Ne III]/Hβ has higher sensitivity to T*, is independent of morphology, and is insensitive to shocks in our objects. These observations should be useful data points for a first empirical calibration of nebular diagnostics of T*, which we attempt for LMC metallicity.

Abstract Copyright:

Journal keyword(s): Galaxies: ISM - ISM: H II Regions - Galaxies: Magellanic Clouds - Stars: Fundamental Parameters - Stars: Wolf-Rayet - ISM: Supernova Remnants

Simbad objects: 46

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Number of rows : 46
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6487 1
2 CPD-69 177 WD* 03 10 31.0195960176 -68 36 03.380768388 10.757 11.413 11.394 11.47 11.558 DA3.0 254 0
3 SH 2-212 HII 04 40 36.50 +50 27 44.3           ~ 96 2
4 SNR J045447-662528 SNR 04 54 48.00 -66 25 42.0           ~ 109 0
5 DEM L 34 HII 04 56 34.3 -66 26 52           ~ 101 0
6 LHA 120-N 44 EmO 05 22 06.9 -67 56 46           ~ 186 1
7 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 16387 1
8 DEM L 174 HII 05 24 22 -68 31.8           ~ 14 0
9 LHA 120-N 51D HII 05 25 17.3 -67 22 47           ~ 111 0
10 HD 36521 WR* 05 26 30.2591541144 -68 50 27.500574192   12.156 12.317 12.529   WC4+O6III/V+O 82 0
11 Brey 33 WR* 05 26 36.8640 -68 50 59.640   14.591 14.77     WN4(h)a 29 0
12 LHA 120-N 144 HII 05 26 42.5 -68 49 34           ~ 67 0
13 [GMP94] 496 * 05 26 44.2108 -68 48 42.116   13.50 13.73     O5V(f) 9 0
14 LH 58 As* 05 26 45 -68 49.9   7.97 7.96     ~ 58 0
15 HD 269546 WR* 05 26 45.3202797576 -68 49 52.787839260 9.00 9.83 9.86 9.76 9.76 WN5b(h)+B3I 104 0
16 NGC 1931 OpC 05 31 23 +34 14.0     10.1     ~ 122 0
17 NGC 2020 EmO 05 33 10.6 -67 42 45           ~ 34 0
18 M 42 HII 05 35 01.5 -05 26 24           ~ 3951 0
19 BI 229 Pu* 05 35 32.1627904200 -66 02 37.668974208 12.290 12.705 12.894 13.206 12.881 O7III 20 0
20 NGC 2030 HII 05 35 33.6 -66 02 26           ~ 69 0
21 LH 83 As* 05 35 34 -66 03.0           ~ 40 1
22 [O96] D243-5 * 05 35 36.25 -66 01 14.7   13.683 13.979     ~ 3 0
23 NAME Ori A MoC 05 38 -07.1           ~ 2881 0
24 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1126 2
25 [L72] LH 114-7 * 05 43 13.0005 -67 51 16.007   13.41 13.66     O2III(f*)+OV 15 0
26 SK -67 250 EB* 05 43 15.6408168672 -67 51 10.456101396 11.314 12.631 12.541   12.781 OB 17 0
27 LHA 120-N 70 HII 05 43 17.5 -67 50 48           ~ 81 0
28 RHV 0543275-675146 * 05 43 17.8708528056 -67 50 34.487560680   13.871 13.920     O5:III:e 6 0
29 LH 114 As* 05 43 18 -67 51.5     11.32     ~ 36 0
30 NGC 2122 As* 05 48 55 -70 04.1     10.43     ~ 91 0
31 MMB G192.600-00.048 Y*O 06 12 54.0100 +17 59 23.200           ~ 374 0
32 IC 2162 HII 06 13 04.1 +17 58 44           ~ 351 2
33 IRAS 06121+1221 MIR 06 14 55.86048 +12 20 40.4088           ~ 41 0
34 SH 2-271 HII 06 15.2 +12 22           ~ 83 1
35 IC 466 HII 07 08 37 -04 18.8           ~ 46 0
36 NGC 2359 HII 07 18 30.000 -13 13 36.00           ~ 163 0
37 SH 2-305 HII 07 30 04.1 -18 32 13           ~ 53 0
38 SH 2-307 HII 07 35 33 -18 45.6           ~ 60 2
39 NGC 3199 HII 10 16 32.8 -57 56 02           ~ 63 1
40 LAWD 37 WD* 11 45 42.9169346379 -64 50 29.461957832 11.08 11.725 11.513 11.34 11.163 DQ 249 0
41 SH 2-148 HII 22 56 21 +58 31.5           ~ 65 0
42 SH 2-152 HII 22 58 40.8107767416 +58 46 59.226036024           ~ 136 1
43 IC 1470 HII 23 05 09.9 +60 14 31   11.5       ~ 169 1
44 [L72] LH 117-214 * ~ ~           O3-4 1 0
45 [L72] LH 117-140 * ~ ~           O3-4(f) 1 0
46 [L72] LH 117-118 * ~ ~           O4:III(f) 2 0

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2022.11.26-09:54:14

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