2009A&A...507.1327H


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.11CEST01:18:42

2009A&A...507.1327H - Astronomy and Astrophysics, volume 507, 1327-1343 (2009/12-1)

The size-density relation of extragalactic HII regions.

HUNT L.K. and HIRASHITA H.

Abstract (from CDS):

We investigate the size-density relation in extragalactic HII regions, with the aim of understanding the role of dust and different physical conditions in the ionized medium. First, we compiled several observational data sets for Galactic and extragalactic HII regions and confirm that extragalactic HII regions follow the same size (D)-density (n) relation as Galactic ones (n∝D–1), rather than a relation with constant luminosity (n∝D–1.5). Motivated by the inability of static models to explain this, we then modelled the evolution of the size-density relation of HII regions by considering their star formation history, the effects of dust, and pressure-driven expansion. The results are compared with our sample data whose size and density span roughly six orders of magnitude. The extragalactic samples cannot be understood as an evolutionary sequence with a single initial condition. Thus, the size-density relation does not result from an evolutionary sequence of HII regions but rather reflects a sequence with different initial gas densities (``density hierarchy''). We also find that the size of many HII regions is limited by dust absorption of ionizing photons, rather than consumption by ionizing neutral hydrogen. Dust extinction of ionizing photons is particularly severe over the entire lifetime of compact HII regions with typical gas densities of >103cm–3. Hence, as long as the number of ionizing photons is used to trace massive star formation, much star-formation activity could be missed. Such compact dense environments, the ones most profoundly obscured by dust, have properties similar to ``maximum-intensity starbursts''. This implies that submillimeter and infrared wavelengths may be necessary to accurately assess star formation in these extreme conditions both locally and at high redshift.

Abstract Copyright:

Journal keyword(s): dust, extinction - galaxies: dwarf - galaxies: evolution - galaxies: ISM - galaxies: star clusters - HII regions

Simbad objects: 46

goto Full paper

goto View the reference in ADS

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 - 2021
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11265 1
2 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3013 2
3 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9755 1
4 NGC 450 H2G 01 15 30.470 -00 51 38.98   13.4   13.3 13.2 ~ 208 0
5 QSO B0125-0635 QSO 01 27 35.5241670251 -06 19 35.428005150 14.75 15.05 14.48 14.06 13.70 ~ 91 0
6 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5277 1
7 NGC 604 HII 01 34 32.1 +30 47 01           ~ 555 0
8 NGC 1140 EmG 02 54 33.5258827369 -10 01 43.135585379 12.41 12.84 12.49 13.6 13.5 ~ 268 1
9 NGC 1156 rG 02 59 42.8526900556 +25 14 28.350265697 12.13 12.32 11.74     ~ 285 1
10 SBSG 0335-052 bCG 03 37 44.04 -05 02 38.5     16.65     ~ 439 1
11 2MASX J04404725+6744098 EmG 04 40 47.3174041718 +67 44 09.376077782   16.0       ~ 34 0
12 NGC 1741 IG 05 01 38.3 -04 15 25   13.7   13.02 13.6 ~ 252 0
13 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15283 1
14 M 42 HII 05 35 17.3 -05 23 28           ~ 3786 0
15 RMC 136 Cl* 05 38 42.396 -69 06 03.36           ~ 1785 1
16 UGCA 116 H2G 05 55 42.645 +03 23 32.23 10.74 11.68 11.46   11.82 ~ 508 0
17 NGC 2363 G 07 28 29.83 +69 11 32.8   15.5       ~ 251 1
18 NGC 2363A HII 07 28 42.8 +69 11 21           ~ 543 3
19 NGC 2366 H2G 07 28 51.85 +69 12 31.1 12.25 11.86 11.39 11.33   ~ 712 0
20 IC 2184 PaG 07 29 27.015 +72 07 51.48   14.00       ~ 90 1
21 LEDA 2790884 bCG 08 25 55.521 +35 32 31.96   18.2       ~ 106 1
22 ESO 495-21 bCG 08 36 15.190 -26 24 33.66 12.04 11.93 11.45 11.09 12.3 ~ 513 3
23 UGC 4483 GiG 08 37 03.29 +69 46 29.2 15.70 15.46 14.98 14.89   ~ 272 0
24 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 1018 1
25 Mrk 1236 GiP 09 49 54.12 +00 36 58.5           ~ 34 0
26 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5445 6
27 GUM 29 HII 10 24 14.6 -57 46 58           ~ 195 0
28 Mrk 33 IG 10 32 31.956 +54 24 03.53 13.29 13.66 13.13 12.71 12.27 ~ 333 1
29 UGC 6456 bCG 11 28 00.43 +78 59 38.4   14.50       ~ 313 1
30 6dFGS gJ115111.7-203557 H2G 11 51 11.7 -20 35 56   15.67   15.35   ~ 81 1
31 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1580 0
32 NGC 4228 SBG 12 15 39.174 +36 19 36.80 10.63 10.30 9.93 9.74   ~ 880 1
33 LEDA 39402 H2G 12 17 17.093 -28 02 32.67   17       ~ 127 0
34 ESO 380-27 H2G 12 25 46.9 -36 14 01   17.47   16.52   ~ 97 1
35 Mrk 209 bCG 12 26 16.02 +48 29 36.6   15.3       ~ 311 0
36 Mrk 59 AGN 12 59 00.288 +34 50 42.45           ~ 309 2
37 LEDA 46982 bCG 13 25 48.60 -11 36 38.0           ~ 76 0
38 IC 4249 EmG 13 27 06.5668959889 -27 57 23.387639135   14.48 14.57 13.52   ~ 80 0
39 NGC 5253 AGN 13 39 55.990 -31 38 24.11 11.48 10.94 10.49 10.33   ~ 1285 4
40 MCG+07-29-060 QSO 14 17 01.716 +43 30 13.52   15.6       ~ 155 0
41 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2739 4
42 RCW 117 HII 17 09 34.0 -41 36 12           ~ 65 3
43 ESO 338-4 IG 19 27 58.338 -41 34 30.81   13.55 13.21 13.14 13.43 ~ 212 1
44 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2304 2
45 Mrk 930 AGN 23 31 58.630 +28 56 50.51 14.27 15.04 14.63 14.56 14.46 ~ 125 0
46 NAME Local Group GrG ~ ~           ~ 7226 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2009A&A...507.1327H and select 'bookmark this link' or equivalent in the popup menu


2021.04.11-01:18:42

© Université de Strasbourg/CNRS

    • Contact