2012A&A...542L..21R


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST01:59:12

2012A&A...542L..21R - Astronomy and Astrophysics, volume 542, L21-21 (2012/6-1)

GREAT confirms transient nature of the circum-nuclear disk.

REQUENA-TORRES M.A., GUESTEN R., WEISS A., HARRIS A.I., MARTIN-PINTADO J., STUTZKI J., KLEIN B., HEYMINCK S. and RISACHER C.

Abstract (from CDS):

We report SOFIA/GREAT, Herschel/HIFI, and ground-based velocity-resolved spectroscopy of carbon monoxide (CO) rotational transitions from J=2-1 to J=16-15 toward two positions in the circum-nuclear disk (CND) in our Galactic center. Radiative transfer models were used to derive information on the physical state of the gas traced by CO. The excitation of the CO gas cannot be explained by a single physical component, but is clearly the superposition of various warm gas phases. In a two-component approach, our large velocity gradient (LVG) analysis suggests high temperatures of ∼200K with moderate gas densities of only ∼104.5cm–3 for the bulk of the material. A higher excited phase, carrying ∼20-30% of the column densities, is warmer (∼300-500K) but only slightly denser (∼105.3cm–3). These densities are too low to self-stabilize the clumps against their high internal turbulence and fall below the Roche density (>107cm–3) at 1.5pc galactocentric distance. We conclude that the bulk of the material in the CND is not organized by self-gravity nor stable against tidal disruption, and must be transient.

Abstract Copyright:

Journal keyword(s): ISM: clouds - ISM: kinematics and dynamics - ISM: molecules - Galaxy: center - radio lines: ISM

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Galactic Circumnuclear Disk PoG 17 45 40.0 -29 00 28           ~ 110 0
2 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3446 3
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11533 0

    Equat.    Gal    SGal    Ecl

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2020.07.04-01:59:12

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