2015A&A...584A.102H


Query : 2015A&A...584A.102H

2015A&A...584A.102H - Astronomy and Astrophysics, volume 584A, 102-102 (2015/12-1)

Chemical features in the circumnuclear disk of the Galactic Center.

HARADA N., RIQUELME D., VITI S., JIMENEZ-SERRA I., REQUENA-TORRES M.A., MENTEN K.M., MARTIN S., ALADRO R., MARTIN-PINTADO J. and HOCHGUERTEL S.

Abstract (from CDS):

The circumnuclear disk (CND) of the Galactic center is exposed to many energetic phenomena coming from the supermassive black hole Sgr A* and from stellar activities. These energetic activities can affect the chemical composition in the CND through interaction with UV photons, cosmic rays, X-rays, and shock waves. We aim to constrain the physical conditions present in the CND through chemical modeling of observed molecular species detected toward it. We analyzed a selected set of molecular line data taken toward a position in the southwest lobe of the CND with the IRAM 30m and APEX 12-m telescopes and derived the column density of each molecule via a large velocity gradient (LVG) analysis. The determined chemical composition is compared with a time-dependent, gas-grain chemical model based on the UCL_CHEM code,which includes the effects of shock waves with varying physical parameters. We detect molecules, such as CO, HCN, HCO+, HNC, CS, SO, SiO, NO, CN, H2CO, HC3N, N2H+, and H3O+, and obtain their column densities. Total hydrogen densities obtained from LVG analysis range between 2x104 and 1x106cm–3 and most species indicate values around several x105cm–3. These values are lower than those corresponding to the Roche limit, which shows that the CND is tidally unstable. The chemical models show good agreement with the observations in cases where the density is ∼104cm–3, the cosmic-ray ionization rate is high, >10–15s–1, or shocks with velocities >40km/s have occurred. Comparison of models and observations favors a scenario where the cosmic-ray ionization rate in the CND is high, but precise effects of other factors, such as shocks, density structures, UV photons, and X-rays from the Sgr A*, must be examined with higher spatial resolution data.

Abstract Copyright:

Journal keyword(s): ISM: molecules - Galaxy: center

Simbad objects: 9

goto Full paper

goto View the references in ADS

Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME Sgr C MoC 17 44 36.3 -29 28 13           ~ 343 0
2 GCM -0.13 -0.08 MoC 17 45 25.2 -29 05 30           ~ 118 1
3 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13449 0
4 NAME Galactic Circumnuclear Disk PoG 17 45 40.0 -29 00 28           ~ 148 0
5 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4049 3
6 GCM -0.02 -0.07 MoC 17 45 50.4 -28 59 06           ~ 158 0
7 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 700 0
8 NAME Sgr B1 MoC 17 47 02.0 -28 31 57           ~ 152 0
9 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2150 1

To bookmark this query, right click on this link: simbad:objects in 2015A&A...584A.102H and select 'bookmark this link' or equivalent in the popup menu


2023.02.02-18:45:19

© Université de Strasbourg/CNRS

    • Contact