2014A&A...571A..90B


Query : 2014A&A...571A..90B

2014A&A...571A..90B - Astronomy and Astrophysics, volume 571A, 90-90 (2014/11-1)

Resolving the shocked gas in HH 54 with Herschel. CO line mapping at high spatial and spectral resolution.

BJERKELI P., LISEAU R., BRINCH C., OLOFSSON G., SANTANGELO G., CABRIT S., BENEDETTINI M., BLACK J.H., HERCZEG G., JUSTTANONT K., KRISTENSEN L.E., LARSSON B., NISINI B. and TAFALLA M.

Abstract (from CDS):

The HH 54 shock is a Herbig-Haro object, located in the nearby Chamaeleon II cloud. Observed CO line profiles are due to a complex distribution in density, temperature, velocity, and geometry. Resolving the HH 54 shock wave in the far-infrared (FIR) cooling lines of CO constrain the kinematics, morphology, and physical conditions of the shocked region. We used the PACS and SPIRE instruments on board the Herschel space observatory to map the full FIR spectrum in a region covering the HH 54 shock wave. Complementary Herschel-HIFI, APEX, and Spitzer data are used in the analysis as well. The observed features in the line profiles are reproduced using a 3D radiative transfer model of a bow-shock, constructed with the Line Modeling Engine code (LIME). The FIR emission is confined to the HH 54 region and a coherent displacement of the location of the emission maximum of CO with increasing J is observed. The peak positions of the high-J CO lines are shifted upstream from the lower J CO lines and coincide with the position of the spectral feature identified previously in CO (10-9) profiles with HIFI. This indicates a hotter molecular component in the upstream gas with distinct dynamics. The coherent displacement with increasing J for CO is consistent with a scenario where IRAS 12500-7658 is the exciting source of the flow, and the 180K bow-shock is accompanied by a hot (800 K) molecular component located upstream from the apex of the shock and blueshifted by -7km/s. The spatial proximity of this knot to the peaks of the atomic fine-structure emission lines observed with Spitzer and PACS ([OI]63, 145µm) suggests that it may be associated with the dissociative shock as the jet impacts slower moving gas in the HH 54 bow-shock.

Abstract Copyright:

Journal keyword(s): ISM: individual objects: HH 54 - ISM: molecules - ISM: abundances - ISM: jets and outflows - stars: winds, outflows

Simbad objects: 6

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Number of rows : 6
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 NAME Cha II MoC 12 54 -77.2           ~ 316 0
2 2MASS J12534285-7715114 Y*O 12 53 42.856 -77 15 11.48           M6.5 19 0
3 HH 54 HH 12 55 49.5 -76 56 08           ~ 119 0
4 HH 54B HH 12 55 50.3 -76 56 23           ~ 30 0
5 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 395 0
6 [DE95] LDN 1157 B1 out 20 39 11 +68 01.3           ~ 224 0

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2022.08.09-21:59:38

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