2000A&A...360...49H


Query : 2000A&A...360...49H

2000A&A...360...49H - Astronomy and Astrophysics, volume 360, 49-56 (2000/8-1)

Probing circumnuclear molecular gas in NGC 5793 with OH absorption.

HAGIWARA Y., DIAMOND P.J., NAKAI N. and KAWABE R.

Abstract (from CDS):

We have observed the nuclear region of an edge-on spiral galaxy NGC 5793 with VLBI in order to determine the morphology of the central continuum source at 6 and 18 cm and the distribution of OH molecular gas at 18 cm on parsec scales. NGC 5793, with a type 2 Seyfert nucleus, is known to have peculiar H2O maser features in its center, indicating the presence of a rotating disk/torus (Hagiwara et al., 1997PASJ...49..171H). Previous interferometric observations could not clarify both the continuum and OH gas structures due to low angular resolution (Gardner & Whiteoak, 1986MNRAS.221..537G, Gardner et al., 1992MNRAS.258..296G). We find multiple continuum peaks forming a bent jet, though the observed peculiar morphology of the continuum source has no straightforward interpretation. We have also imaged the distribution of OH absorption toward the central continuum source. Due to the relative weakness of the continuum emission only the central continuum peak shows evidence of detectable opacity of the OH absorbing gas. The OH velocity field contour map reveals a velocity gradient of 8.7km/s/pc nearly along the galaxy's optical axis. If we suppose that the observed OH velocity gradient is caused by simple solid rotation around the nucleus of the galaxy, the central binding mass is 4.2x108M. The direction of the OH velocity field shows a reversal of a sense of rotation with respect to that of the outer galactic disk observed by CO (1-0), implying the existence of an independent kinematical system in the central 10 parsec-scale region of the galaxy. Alternatively, the observed OH molecular absorption might possibly arise in the parsec-scale circumnuclear region of NGC 5793.

Abstract Copyright:

Journal keyword(s): masers - ISM: kinematics and dynamics - galaxies: active - galaxies: ISM

Nomenclature: Table 2, Figs 1, 2: [HDN2000] CN(WW) (Nos C1(C), C1(NE), C1(SW), C2(C), C2(W), C2(E)).

CDS comments: Calibrator J1507-168 (J omitted by author) = RORF 1504-166

Simbad objects: 17

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Number of rows : 17
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3124 2
2 M 77 GiP 02 42 40.7091669408 -00 00 47.859690204 9.70 9.61 8.87 10.1 9.9 ~ 4322 2
3 ICRF J092703.0+390220 Sy1 09 27 03.0138528936 +39 02 20.850343332   17.17 17.00 16.486   ~ 959 1
4 NGC 3079 Sy2 10 01 57.8789863992 +55 40 47.449758324 11.57 11.54 10.86     ~ 1311 3
5 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3520 2
6 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2228 3
7 M 64 SyG 12 56 43.696 +21 40 57.57   9.36 8.52     ~ 876 2
8 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1365 2
9 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4059 2
10 NGC 5793 Sy2 14 59 24.807 -16 41 36.55   14.47 13.32 12.77   ~ 131 1
11 QSO B1504-167 QSO 15 07 04.7863621776 -16 52 30.274176216   18.40 18.5 17.00   ~ 221 1
12 [HDN2000] C2(E) Rad ~ ~           ~ 3 0
13 [HDN2000] C2(C) Rad ~ ~           ~ 3 0
14 [HDN2000] C1(SW) Rad ~ ~           ~ 1 0
15 [HDN2000] C1(C) Rad ~ ~           ~ 3 1
16 [HDN2000] C1(NE) Rad ~ ~           ~ 2 0
17 [HDN2000] C2(W) Rad ~ ~           ~ 3 0

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2022.05.20-18:40:51

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