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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



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ID: 225876.0, MPI für Astronomie / Publikationen_mpia
Very cold cores in the Taurus Molecular Ring as seen by ISO
Authors:Tóth, L. V.; Haas, M.; Lemke, D.; Mattila, K.; Onishi, T.
Date of Publication (YYYY-MM-DD):2004
Title of Journal:Astronomy and Astrophysics
Volume:420
Start Page:533
End Page:546
Review Status:not specified
Audience:Not Specified
Abstract / Description:Three prominent cold objects of the
<ASTROBJ>Taurus Molecular Ring</ASTROBJ>
(<ASTROBJ>TMR</ASTROBJ>) were revealed by our
ISOPHOT 200 ‚‚mu;m map of the south-eastern part
of the <ASTROBJ>Heiles Cloud 2</ASTROBJ>
(<ASTROBJ>HCL 2</ASTROBJ>) cloud complex. One
corresponds to the cyanopolyyne peak region of
the <ASTROBJ>TMC-1</ASTROBJ> ridge,
(<ASTROBJ>TMC-1 CP</ASTROBJ>), one is the
<ASTROBJ>HCL2-E</ASTROBJ> cloud, and one which
we call <ASTROBJ>HCL2-ES</ASTROBJ> lies south of
TMC-1. The 200/100 ‚‚mu;m colour temperatures and
column densities of the three ISOPHOT cold
clouds are ‚‚ap;12 K, and 1.2 ‚‚plusmn; 0.7
‚‚times; 1022 cm-2
respectively, as calculated from ISO/IRAS
surface brightnesses. As Nagoya-4 m
C18 (1-0) spectra show, these are
dense molecular clouds with N(H)‚‚gt;
1021 cm-2 column density
peaks. The ISOPHOT 200 ‚‚mu;m surface brightness
is well correlated with the C18O line
intensity (corr. coef.‚‚ap; 70%). The large dust
particle emissivity is found to be increased in
the prototypical very dense core TMC-1 CP. As
the low linewidths (‚‚Delta; v=0.8 ‚‚plusmn; 0.2
km s-1) indicate, the level of
turbulent energy density is 50% lower in these
three clouds than in other clouds of HCL2. Dense
cores were identified inside the C18O
clouds by NH3 measurements with the
Effelsberg-100 m telescope and Nobeyama-45 m
H13CO+ data. The density of
the dense cores is n‚‚ge;1.1 ‚‚times;
105 cm-3, and their kinetic
temperatures are ‚‚la;10 K, in good agreement
with the FIR results. The total molecular gas
mass in the gravitationally bound cloud cores of
TMC-1 CP and HCL2-E is about 21
M‚‚odot; and 8 M‚‚odot;
respectively. The cores, TMC-1 CPb and HCL2-Eab
are associated with 3 low mass YSO candidate
2MASS point sources, while 35 other low mass YSO
candidates are seen elsewhere in TMR south, which
we consider as evidence for ongoing low mass
star formation.
Free Keywords:ISM: clouds; dust; extinction; ISM:
; individual objects: Taurus clouds; ISM:
; molecules; ISM: structure; stars: formation
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
External Affiliations:K‚‚ouml;nigstuhl, 17, 69117, Heidelberg, Germany;
Department of Astronomy ofthe Lor‚‚aacute;nd
E‚‚ouml;tv‚‚ouml;s University,
P‚‚aacute;zm‚‚aacute;ny P‚‚eacute;ter
s‚‚eacute;t‚‚aacute;ny 1, 1117 Budapest,
Hungary), AB(Max-Planck-Instutute f‚‚uuml;r
Astronomie, K‚‚ouml;nigstuhl, 17, 69117,
Heidelberg, Germany), AC(Max-Planck-Instutute
f‚‚uuml;r Astronomie, K‚‚ouml;nigstuhl, 17,
69117, Heidelberg, Germany), AD(Helsinki
University Observatory, PO Box 14
T‚‚auml;htitorninm‚‚auml;ki, 00014 University of
Helsinki, Finland), AE(Department of
Astrophysics, Nagoya University, Chikusa-ku,
Nagoya 464-8602, Japan)
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi... [ID No:1]
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