2008A&A...487..583B


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.23CET00:49:10

2008A&A...487..583B - Astronomy and Astrophysics, volume 487, 583-594 (2008/8-4)

CaII and NaI absorption signatures from extraplanar gas in the halo of the Milky Way.

BEN BEKHTI N., RICHTER P., WESTMEIER T. and MURPHY M.T.

Abstract (from CDS):

We analyse absorption characteristics and physical conditions of extraplanar intermediate- and high-velocity gas to study the distribution of the neutral and weakly ionised Milky Way halo gas and its relevance for the evolution of the Milky Way and other spiral galaxies. We combine optical absorption line measurements of CaII/NaI and 21cm emission line observations of HI along 103 extragalactic lines of sight towards quasars (QSOs) and active galactic nuclei (AGN). The archival optical spectra were obtained with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope, while the 21cm HI observations were carried out using the 100-m radio telescope at Effelsberg. The analysis of the UVES spectra shows that single and multi-component CaII/NaI absorbers at intermediate and high velocities are present in about 35 percent of the sight lines, indicating the presence of neutral extraplanar gas structures. In some cases the CaII/NaI absorption is connected with HI 21cm intermediate- or high-velocity gas with HI column densities in the range of 1018 to 1020/cm2 (i.e., the classical IVCs and HVCs), while other CaII/NaI absorbers show no associated HI emission. The observed HI line widths vary from ΔvFWHM=3.2km/s to 32.0km/s indicating a range of upper gas temperature limits of 250K up to about 22500K. Our study suggests that the Milky Way halo is filled with a large number of neutral gaseous structures whose high column density tail represents the population of common HI high-velocity clouds seen in 21cm surveys. The CaII column density distribution follows a power-law f(N)=CNβ with a slope of β≃-1.6, thus comparable to the distribution found for intervening metal-line systems toward QSOs. Many of the statistical and physical properties of the CaII absorbers resemble those of strong (Wλ2796>0.3Å) MgII absorbing systems observed in the circumgalactic environment of other galaxies, suggesting that both absorber populations may be closely related.

Abstract Copyright:

Journal keyword(s): Galaxy: halo - ISM: structure - quasars: absorption lines - galaxies: halo

CDS comments: Table 2. J123437-075843 is a misprint for J123437+075843 ([VV2006] J123437.6+075842 in Simbad).

Simbad objects: 49

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Number of rows : 49

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 QSO J0003-2323 QSO 00 03 44.9144470879 -23 23 55.075352888     16.7     ~ 69 0
2 QSO B0002-422 QSO 00 04 48.2718823544 -41 57 28.150311306   17.44 17.21     ~ 154 0
3 IC 10 G 00 20 23.16 +59 17 34.7   13.6 9.5     ~ 1019 0
4 NAME Magellanic Stream HVC 00 32 -30.0           ~ 833 1
5 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11155 1
6 NGC 247 LSB 00 47 08.554 -20 45 37.44 10.11 9.61 9.10 8.87   ~ 378 2
7 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9656 1
8 NGC 300 GiG 00 54 53.4460065856 -37 41 03.182962667 8.83 8.69 8.13 7.46   ~ 1345 2
9 PHL 957 QSO 01 03 11.2740814277 +13 16 17.810502093   16.97 16.57     ~ 330 0
10 QSO J0105-1846 QSO 01 05 16.7912539296 -18 46 41.986608187     18.3     ~ 73 0
11 QSO B0109-353 QSO 01 11 43.6321355926 -35 03 00.586979841   16.6 16.9     ~ 72 0
12 QSO B0112-30 QSO 01 15 04.8737306476 -30 25 14.963003446           ~ 45 1
13 QSO B0122-379 QSO 01 24 17.3723276055 -37 44 22.919153842     17.1     ~ 113 0
14 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5232 1
15 QSO J0139-0824 QSO 01 39 01.4056855981 -08 24 44.049404116   19.05 18.80     ~ 45 0
16 QSO J0153-4311 QSO 01 53 27.1919509912 -43 11 38.096734050     16.80     ~ 44 0
17 QSO B0216+0803 QSO 02 18 57.3583341300 +08 17 27.351147286     18.1     ~ 89 0
18 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1400 1
19 QSO B0450-1310 QSO 04 53 13.5743802506 -13 05 55.082840035   13.2 16.5     ~ 87 2
20 4C -02.19 QSO 05 01 12.80988366 -01 59 14.2562534   19.1 18.4 19.04   ~ 529 1
21 HE 0515-4414 QSO 05 17 07.6239672230 -44 10 55.578294294 14.74 15.49 15.16     ~ 101 0
22 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15122 1
23 QSO B0810+2554 QSO 08 13 31.2926 +25 45 03.061   16.58 16.18     ~ 82 1
24 7C 082754.29+242103.00 QSO 08 30 52.08619070 +24 10 59.8204032   17.62 17.26 16.30   ~ 472 1
25 QSO B0926-0201 QSO 09 29 13.5729513057 -02 14 46.227223685   16.59 16.31     ~ 18 0
26 QSO B0952+179 QSO 09 54 56.82361250 +17 43 31.2222114   17.31 17.23     ~ 197 1
27 NAME M 81-82 Group GrG 09 55 +69.1           ~ 642 0
28 QSO B1036-2257 QSO 10 39 09.5073121205 -23 13 26.400097195   18.0 18.0     ~ 39 0
29 QSO J1039-2719 QSO 10 39 21.8516211943 -27 19 16.434979322     17.4     ~ 86 0
30 PG 1101-264 QSO 11 03 25.2992132616 -26 45 15.809136362   16.08 16.02     ~ 238 0
31 LBQS 1209+1046 QSO 12 11 40.6044459296 +10 30 02.077569939   18.52 18.37     ~ 107 0
32 Ton 1480 QSO 12 15 09.2309064973 +33 09 55.239074378   16.56 16.45     ~ 45 0
33 4C -02.55 QSO 12 32 00.0157879377 -02 24 04.790684994   17.41 17.06 16.4   ~ 387 1
34 LBQS 1232+0815 QSO 12 34 37.5507010309 +07 58 43.372966617     18.4     ~ 115 0
35 QSO B1331+170 QSO 13 33 35.7828550018 +16 49 04.012528106   16.84 16.71 16.41   ~ 415 0
36 QSO J1344-1035 QSO 13 44 27.0638968862 -10 35 41.748550205     17.1     ~ 46 0
37 QSO J1356-1101 QSO 13 56 46.8321881764 -11 01 29.227943266   19.0 19.20 17.7   ~ 43 1
38 NAME M101 Group GrG 14 03 +54.3           ~ 88 1
39 HE 1434-1600 QSO 14 36 49.6201434600 -16 13 41.194725080   17.08 15.8 16.00   ~ 44 1
40 LBQS 1444+0126 QSO 14 46 53.0500684156 +01 13 55.922982686   18.71 18.38     ~ 59 0
41 QSO B1448-232 QSO 14 51 02.5094965667 -23 29 31.105639377   17.13 16.96     ~ 119 2
42 NGC 6822 G 19 44 56.199 -14 47 51.29   18 8.1     ~ 1449 0
43 PHL 1811 Sy1 21 55 01.5123415724 -09 22 24.351917710   13.9 16.8 14.1   ~ 159 1
44 QSO J2227-2243 QSO 22 27 56.9352859002 -22 43 02.603505383     17.60     ~ 17 0
45 QSO B2314-409 QSO 23 16 46.9196152973 -40 41 21.105711875   17.9 17.9     ~ 62 1
46 QSO B2348-147 BLL 23 51 29.8151829970 -14 27 56.845507757     16.9     ~ 73 1
47 NAME Anticenter Shell ? ~ ~           ~ 6 0
48 NAME IV Spur PoC ~ ~           ~ 21 0
49 NAME IV Arch PoC ~ ~           ~ 52 1

    Equat.    Gal    SGal    Ecl

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2021.01.23-00:49:10

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