2010ApJ...721..960N

Query : 2010ApJ...721..960N

2010ApJ...721..960N - Astrophys. J., 721, 960-974 (2010/October-1)

Cosmic origins spectrograph and FUSE observations of T ∼ 105 K gas in a nearby galaxy filament.

NARAYANAN A., WAKKER B.P., SAVAGE B.D., KEENEY B.A., SHULL J.M., STOCKE J.T. and SEMBACH K.R.

Abstract (from CDS):

We present a clear detection of a broad Lyα absorber (BLA) with a matching O VI line in the nearby universe. The BLA is detected at {z(Lyα) = 0.01028} in the high signal-to-noise ratio spectrum of Mrk 290 obtained using the Cosmic Origins Spectrograph. The Lyα absorption has two components, with {b({H i}) = 55 ±1} km/s and {b({H i}) = 33 ±1} km/s, separated in velocity by v ∼ 115 km/s. The O VI, detected by the Far-Ultraviolet Spectroscopic Explorer at {z({O vi}) = 0.01027}, has a {b({O vi}) = 29 ±3} km/s and is kinematically well aligned with the broader H I component. The non-detection of other ions such as C II, Si II, Fe II, C III, Si III, C IV, Si IV, and N V at the same velocity as the BLA and the O VI implies that the absorber is tracing highly ionized gas. The different line widths of the BLA and O VI suggest a temperature of T = 1.4x105 K in the absorber. Photoionization, collisional ionization equilibrium as well as non-equilibrium collisional ionization models do not explain the ion ratios at this temperature. The observed line strength ratios and line widths favor an ionization scenario in which both ion-electron collisions and UV photons contribute to the ionization in the gas. Such a model requires a low metallicity of ~-1.7 dex, ionization parameter of log U ∼ -1.4, a large total hydrogen column density of N(H) ∼ 4x1019/cm2, and a path length of ∼400 kpc. The line of sight to Mrk 290 intercepts at the redshift of the absorber, a megaparsec scale filamentary structure extending over ∼20° in the sky, with several luminous galaxies distributed within ∼1.5 h–1 Mpc projected distance from the absorber. The collisionally ionized gas phase of this absorber is most likely tracing a shock-heated gaseous structure, consistent with a few different scenarios for the origin including an overdense region of the warm-hot intergalactic medium in the galaxy filament or highly ionized gas in the extended halo of one of the galaxies in the filament. In general, BLAs with metals provide an efficient means to study T ∼ 105-106 K gas in galaxy halos and in the intergalactic medium. A substantial fraction of the baryons missing from the present universe is predicted to be in such environments in the form of highly ionized plasma.

Abstract Copyright: ∼

Journal keyword(s): galaxies: clusters: individual: GH 158 - galaxies: halos - galaxies: individual (NGC 5987, NGC 5982, NGC 5985, NGC 5987, NGC 5989) - intergalactic medium - quasars: absorption lines - ultraviolet: general

CDS comments: In Fig. 4: Objects SDSS and 2MASS are not entered in SIMBAD due to an incomplete format.

Simbad objects: 34

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Number of rows : 34
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 6022 1
2 LB 2522 Sy1 13 01 12.9250750776 +59 02 06.693816732   16.04 15.89     ~ 298 0
3 Z 336-28 Sy1 13 53 03.4348964112 +69 18 29.410910460   15.15 14.46     ~ 812 1
4 2XMM J135315.8+634546 Sy1 13 53 15.8311116864 +63 45 45.683126676   14.54 14.28     ~ 404 1
5 Z 296-15 Sy1 14 36 22.0820611632 +58 47 39.394934844   14.19 13.79     ~ 592 0
6 2MASS J14464593+4035057 Sy1 14 46 45.9392259288 +40 35 05.797233636   16.28 16.11     ~ 302 0
7 GHCG 151 GrG 15 12.4 +55 03   11.6       ~ 6 0
8 Z 297-12 LSB 15 23 51.735 +58 03 11.23   14.6       ~ 85 0
9 NGC 5965 SyG 15 34 02.3002830024 +56 41 08.509684740   13.4       ~ 133 0
10 NVSS J153412+571655 rG 15 34 13.3862564640 +57 17 07.282532472   15.8       ~ 79 1
11 Mrk 290 Sy1 15 35 52.4031021552 +57 54 09.515660508   15.55 15.27     ~ 575 0
12 NGC 5976A LSB 15 36 07.3975009776 +59 33 59.899891140   15.4       ~ 15 0
13 NGC 5976 AG? 15 36 47.9680642728 +59 23 52.017841104   15.9       ~ 10 0
14 NGC 5981 GiG 15 37 53.5014542688 +59 23 30.529061988   14.2       ~ 110 0
15 NGC 5982 LIN 15 38 39.778 +59 21 21.21   12.4       ~ 302 0
16 [FWB89] GrG 229 GrG 15 39.5 +59 10   11.2       ~ 13 0
17 NGC 5985 SyG 15 39 37.0545742176 +59 19 55.216886664   15.24 14.22     ~ 267 0
18 NGC 5987 GiG 15 39 57.3733917696 +58 04 46.195631832   13.3       ~ 98 0
19 SHOC 513 H2G 15 40 54.3243818904 +56 51 39.030034680           ~ 12 0
20 LEDA 2567356 AG? 15 41 09.60 +57 31 51.0   18       ~ 10 0
21 NGC 5989 GiG 15 41 32.7907536480 +59 45 18.897878952   13.6       ~ 45 0
22 MCG+10-22-035 EmG 15 43 48.762 +57 13 59.64   19       ~ 29 0
23 2MASX J15435369+5713235 G 15 43 53.694 +57 13 23.54   18.5       ~ 6 0
24 SBSG 1543+593 LSB 15 44 20.30 +59 12 24.2   17.5 16.9     ~ 55 2
25 MCG+10-22-036 AG? 15 44 53.59 +57 21 41.0   16.5       ~ 21 0
26 MCG+10-22-037 AG? 15 45 18.24606 +57 24 34.9308   16       ~ 15 0
27 Z 297-29 AG? 15 46 24.181 +59 12 55.63   15.7       ~ 11 0
28 Mrk 876 Sy1 16 13 57.1795021224 +65 43 09.952685328   16.03 15.49     ~ 620 0
29 QSO B1626+5529 Sy1 16 27 56.1123628752 +55 22 31.559061504   15.79 15.68     ~ 232 1
30 NAME HVC Complex C HVC 16 34.8 +63 07           ~ 273 1
31 8C 1704+608 Bla 17 04 41.3742408840 +60 44 30.520617000   15.65 15.40 15.30   ~ 782 1
32 ClG 1821+64 ClG 18 21 56.7276 +64 20 55.841           ~ 511 1
33 7C 1821+6419 Sy1 18 21 57.2130271440 +64 20 36.221312076   14.23 14.24     ~ 632 1
34 NAME MR 2251-178 Sy1 22 54 05.8858611984 -17 34 55.402233708   14.99 14.36 15.12   ~ 467 4

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