1999ApJ...510..104B

Query : 1999ApJ...510..104B

1999ApJ...510..104B - Astrophys. J., 510, 104-124 (1999/January-1)

The ionizing stars of extragalactic H II regions.

BRESOLIN F., KENNICUTT R.C.Jr and GARNETT D.R.

Abstract (from CDS):

Medium-resolution spectra from 3650 to 10000 Å are presented for 96 giant H II regions distributed in 20 spiral galaxies. In order to interpret the data, we have calculated two separate grids of photoionization models, adopting single-star atmospheres (Kurucz) and star clusters synthesized with different initial mass functions (IMFs) as ionizing sources. Additional models were computed with more recent non-LTE stellar atmospheres, in order to check the effects of different stellar ionizing fluxes. We use the radiation softness parameter η'=([O II]/[O III])/([S II]/[S III]) of Vílchez & Pagel to test for a metallicity dependence of the effective temperatures of the ionizing stars. Our results are consistent with a significant decrease in mean stellar temperatures of the ionizing stars with increasing metallicity. The magnitude of the effect, combined with the behavior of the He I λ5876/Hβ ratio, suggest a smaller upper mass limit for star formation at abundances higher than solar, even when considering the effects of metallicity on stellar evolution and atmospheric line blanketing. However, the exact magnitudes of the stellar temperature and IMF variations are dependent on the choice of stellar atmosphere and evolution models used, as well as on uncertainties in the nebular abundance scale at high metallicities. Our results also constrain the systematic behavior of the ionization parameter and the N/O ratio in extragalactic H II regions. The observed spectral sequences are inconsistent with current stellar evolution models, which predict a luminous, hot W-R stellar population in evolved H II regions older than 2-3 Myr. This suggests either that the hardness of the emitted Lyman continuum spectrum has been overestimated in the models or that some mechanism disrupts the H II regions before the W-R phases become important.

Abstract Copyright: ∼

Journal keyword(s): Galaxies: ISM - Galaxies: Spiral

VizieR on-line data: <Available at CDS (J/ApJ/510/104): table3.dat>

Nomenclature: Table 3: [BKG99] M NN NN, [BKG99] NGC NNNN N, N=96.

CDS comments: cross-id. HK = HK NGC, H = [H76], P = [PAV78], CCM, GS = [GS87], D = [DTJ80], Munch = [M59b].

Simbad objects: 102

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Number of rows : 102
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 BA 1-379 HII 00 39 18.84552 +40 21 58.3920           ~ 15 1
2 BA 1-429 HII 00 41 01.37 +41 04 09.1           ~ 4 0
3 BA 1-289 HII 00 41 29.20 +40 51 04.0           ~ 9 0
4 WSTB 37W87 SNR 00 41 30.17 +41 05 01.9 16.460 17.610 19.42     ~ 26 0
5 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12678 1
6 [JSD2015] AP 102 GlC 00 43 34.87 +41 09 53.4 15.31   17.34   15.93 WN3?+neb+abs 27 0
7 BA 1-576 HII 00 44 00.23 +41 48 59.7           ~ 4 0
8 NGC 588 HII 01 32 45.2 +30 38 54 14.59 14.40 14.44 14.89 15.16 ~ 122 1
9 NGC 595 HII 01 33 33.53 +30 41 29.8           ~ 205 0
10 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 5847 1
11 NGC 604 HII 01 34 32.1 +30 47 01           ~ 586 0
12 [BKG99] NGC 628 6 HII 01 36 29.384 +15 48 28.11           ~ 3 0
13 [BKG99] NGC 628 7 HII 01 36 35.5 +15 50 11           ~ 19 0
14 FGW 628A HII 01 36 36.730 +15 46 32.68           ~ 10 0
15 [BKG99] NGC 628 3 HII 01 36 37.670 +15 45 08.43           ~ 9 0
16 [BKG99] NGC 628 5 HII 01 36 38.840 +15 44 21.79           ~ 13 0
17 M 74 G 01 36 41.7451236624 +15 47 01.107512304 10.52 10.00 9.46 9.16   ~ 1741 1
18 [BKG99] NGC 628 4 HII 01 36 44.584 +15 45 06.11           ~ 5 0
19 [BKG99] NGC 628 1 HII 01 36 45.1 +15 47 51           ~ 7 0
20 HK NGC 1569 45 MoC 04 30 46.7 +64 50 59           ~ 23 1
21 NGC 1569 IG 04 30 49.186 +64 50 52.52 11.72 11.86 11.03     ~ 1243 3
22 HK NGC 1569 23 HII 04 30 52.1 +64 50 48           ~ 13 0
23 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1190 2
24 [BKG99] NGC 2403 9 HII 07 36 17.676 +65 38 26.59           ~ 2 0
25 [BKG99] NGC 2403 3 HII 07 36 38.210 +65 36 54.61           ~ 2 0
26 [BKG99] NGC 2403 5 HII 07 36 41.743 +65 33 43.60           ~ 2 0
27 [BKG99] NGC 2403 1 HII 07 36 44.210 +65 36 44.60           ~ 2 0
28 [BKG99] NGC 2403 2 HII 07 36 47.609 +65 37 04.58           ~ 2 0
29 [BKG99] NGC 2403 4 HII 07 36 51.276 +65 36 41.62           ~ 2 0
30 NGC 2403 AGN 07 36 51.3381434280 +65 36 09.650825640 9.31 8.84 8.38 8.19   ~ 1791 1
31 [BKG99] NGC 2403 8 HII 07 36 53.611 +65 37 18.59           ~ 2 0
32 [BKG99] NGC 2403 6 HII 07 36 54.809 +65 35 20.62           ~ 2 0
33 [BKG99] NGC 2403 7 HII 07 37 01.610 +65 38 25.58           ~ 2 0
34 HK NGC 2841 52 HII 09 21 59.230 +50 59 56.90           ~ 2 0
35 HK NGC 2841 51 HII 09 21 59.230 +51 00 05.90           ~ 2 0
36 HK NGC 2841 62 HII 09 22 02.030 +50 59 50.89           ~ 2 0
37 NGC 2841 LIN 09 22 02.6778711696 +50 58 35.737082868 10.43 10.09 9.22     ~ 1073 1
38 HK NGC 3031 652 HII 09 54 56.6 +69 08 47           ~ 14 0
39 [BKG99] NGC 3031 10 PoG 09 55 01.70 +69 12 57.2           ~ 8 0
40 HK NGC 3031 453 HII 09 55 25.0 +69 08 16           ~ 11 0
41 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4456 3
42 HK NGC 3031 268 HII 09 55 53.2 +68 59 04           ~ 10 0
43 HK NGC 3031 230 HII 09 56 00.4 +69 04 02           ~ 7 0
44 [BKG99] NGC 3031 9 PoG 09 56 17.4 +68 49 50           ~ 8 0
45 NGC 3310 AGN 10 38 45.85707 +53 30 11.8940   12.45 12.15     ~ 774 1
46 M 95 GiP 10 43 57.7313485800 +11 42 13.301191332 10.71 10.51 9.73 9.48   ~ 1124 2
47 HK NGC 3351 45 HII 10 43 58.634 +11 43 19.70           ~ 2 0
48 [BKG99] NGC 3351 5 HII 10 43 59.633 +11 39 00.68           ~ 2 0
49 [BKG99] NGC 3368 2 HII 10 46 42.314 +11 49 35.18           ~ 1 0
50 M 96 GiP 10 46 45.744 +11 49 11.78 10.42 10.15 9.25 8.99   ~ 821 1
51 [BKG99] NGC 3368 1 HII 10 46 49.380 +11 48 46.19           ~ 2 0
52 [BKG99] NGC 3521 3 HII 11 05 45.660 -00 01 18.91           ~ 2 0
53 [BKG99] NGC 3521 2 HII 11 05 48.526 -00 00 45.90           ~ 2 0
54 NGC 3521 G 11 05 48.5680991376 -00 02 09.245076540 10.06 9.83 9.02 10.1 9.6 ~ 817 2
55 [BKG99] NGC 3521 1 HII 11 05 49.726 -00 00 28.91           ~ 2 0
56 [BKG99] NGC 3623 1 HII 11 18 55.579 +13 04 06.31           ~ 1 0
57 M 65 GiP 11 18 55.9084654776 +13 05 32.300703672   9.6       ~ 445 1
58 [CPH93] 5Na HII 12 18 26.791 +47 21 09.23           ~ 4 0
59 [BKG99] NGC 4258 2 HII 12 18 43.814 +47 17 32.21           ~ 2 0
60 [B2011] 8 HII 12 18 55.330 +47 20 35.41           ~ 4 0
61 [B2011] 9 HII 12 18 55.94 +47 20 25.5           ~ 3 0
62 [B2011] 10 HII 12 18 56.55 +47 20 15.2           ~ 3 0
63 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2365 3
64 HK NGC 4736 52 HII 12 50 49.6 +41 07 23           ~ 5 0
65 HK NGC 4736 53 HII 12 50 49.6 +41 07 34           ~ 4 0
66 M 94 SyG 12 50 53.0737971432 +41 07 12.900884628 9.15 8.96 8.24 7.78   ~ 1387 2
67 HK NGC 4736 9 HII 12 50 56.3 +41 07 20           ~ 4 0
68 HK NGC 4736 8 HII 12 50 56.3 +41 07 20           ~ 5 0
69 Mrk 59 AGN 12 59 00.288 +34 50 42.45           ~ 317 2
70 [BKG99] NGC 4861 1 HII 12 59 00.350 +34 50 42.79           ~ 1 0
71 [BKG99] NGC 4861 2 HII 12 59 00.749 +34 50 48.80           ~ 1 0
72 NGC 4861 H2G 12 59 02.340 +34 51 33.98   12.90 12.32     ~ 383 2
73 CCM 71A HII 13 29 39.400 +47 08 41.50           ~ 17 0
74 CCM 72 HII 13 29 44.200 +47 10 23.58           ~ 27 0
75 CCM 71 HII 13 29 44.600 +47 10 00.24           ~ 16 0
76 CCM 84 HII 13 29 46.600 +47 12 33.26           ~ 8 0
77 CCM 68 HII 13 29 46.909 +47 09 42.50           ~ 4 0
78 CCM 91 HII 13 29 47.087 +47 13 38.79           ~ 8 0
79 CCM 64 HII 13 29 50.501 +47 09 45.33           ~ 3 0
80 M 51 Sy2 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4333 4
81 CCM 107 HII 13 29 53.1 +47 12 40           ~ 7 0
82 CCM 6A HII 13 29 53.369 +47 12 10.80           ~ 5 0
83 CCM 37A HII 13 29 55.981 +47 11 55.98           ~ 9 0
84 CCM 10 HII 13 29 59.700 +47 13 58.87           ~ 29 0
85 CCM 55 HII 13 30 02.300 +47 09 49.18           ~ 16 0
86 CCM 53 HII 13 30 02.900 +47 09 57.48           ~ 15 0
87 M 83 SBG 13 37 00.91920 -29 51 56.7400 8.85 8.11 7.52 7.21   ~ 2580 2
88 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 2919 2
89 [BKG99] NGC 5701 1 HII 14 39 10.682 +05 20 20.51           ~ 1 0
90 NGC 5701 GiG 14 39 11.0751915840 +05 21 48.493104264 12.03 11.76 10.88     ~ 240 1
91 [BKG99] NGC 5701 2 HII 14 39 16.416 +05 20 47.51           ~ 1 0
92 [BKG99] NGC 6384 5 HII 17 32 21.686 +07 04 46.81           ~ 1 0
93 [BKG99] NGC 6384 4 HII 17 32 22.286 +07 04 52.79           ~ 1 0
94 NGC 6384 AG? 17 32 24.2848390896 +07 03 37.531624968   13.2       ~ 304 0
95 [BKG99] NGC 6384 1 HII 17 32 24.286 +07 02 13.81           ~ 1 0
96 [BKG99] NGC 6384 2 HII 17 32 27.821 +07 04 13.80           ~ 1 0
97 [BKG99] NGC 6384 3 HII 17 32 27.953 +07 04 21.79           ~ 1 0
98 [BKG99] NGC 6384 6 HII 17 32 33.086 +07 05 26.81           ~ 1 0
99 HK NGC 7331 98 HII 22 37 02.222 +34 24 31.50           ~ 2 0
100 HK NGC 7331 95 HII 22 37 02.556 +34 24 06.52           ~ 3 0
101 NGC 7331 LIN 22 37 04.0506038088 +34 24 56.800076508 10.65 10.35 9.48     ~ 1228 2
102 HK NGC 7331 40 HII 22 37 06.089 +34 26 18.49           ~ 3 0

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