J/ApJ/699/742 Properties of cores in the Pipe Nebula (Rathborne+, 2009)
Dense cores in the Pipe Nebula: an improved core mass function.
Rathborne J.M., Lada C.J., Muench A.A., Alves J.F., Kainulainen J.,
Lombardi M.
<Astrophys. J., 699, 742-753 (2009)>
=2009ApJ...699..742R 2009ApJ...699..742R
ADC_Keywords: Molecular clouds ; Extinction
Keywords: dust, extinction - ISM: globules - ISM: molecules - stars: formation -
stars: luminosity function, mass function
Abstract:
In this paper, we derive an improved core mass function (CMF) for the
Pipe Nebula from a detailed comparison between measurements of visual
extinction and molecular-line emission. We have compiled a refined
sample of 201 dense cores toward the Pipe Nebula using a
two-dimensional threshold identification algorithm informed by recent
simulations of dense core populations. Measurements of radial
velocities using complimentary C18O(1-0) observations enable us to
cull out from this sample those 43 extinction peaks that are either
not associated with dense gas or are not physically associated with
the Pipe Nebula. Moreover, we use the derived C18O central
velocities to differentiate between single cores with internal
structure and blends of two or more physically distinct cores,
superposed along the same line of sight. We then are able to produce a
more robust dense core sample for future follow-up studies and a more
reliable CMF than was possible previously.
Description:
Observations of C18O(1-0) molecular line emission toward all 201
extinction peaks identified toward the Pipe Nebula were obtained using
the 12m Arizona Radio Observatory (ARO) and the 22m Mopra telescopes.
The ARO C18O(1-0) observations were conducted over two periods in
2005-2006. In total, 102 of the 201 extinction peaks were observed
with the ARO. Ninety-four of these positions corresponded to cores
within the original list of Alves et al. (2007, Cat. J/A+A/462/L17).
The details of these observations are presented in Muench et al.
(2007ApJ...671.1820M 2007ApJ...671.1820M). Spectra were obtained with the Mopra telescope
toward all remaining identified extinction peaks for which we had no
previous C18O(1-0) data. In total, an additional 99 positions were
observed over the periods 2007 July 3-8 and 2008 July 20-25.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 59 134 Core properties
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See also:
J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [RLM2009] Core identification number
5 A1 --- f_[RLM2009] [b] b means extinction peaks were merged
within this core
7- 11 F5.2 deg GLON Galactic longitude in decimal degrees
13- 16 F4.2 deg GLAT Galactic latitude in decimal degrees
18- 21 F4.1 mag Av Peak extinction
23- 26 F4.2 pc Rad Radius in parsec
28- 31 F4.1 Msun Mass Mass of the core
33- 35 F3.1 10+4cm-3 nH2 H2 density
37- 40 F4.2 K T*A Peak antenna temperature
42- 45 F4.2 km/s vLSR LSR velocity
47- 50 F4.2 km/s dV Velocity difference (δV) between each
extinction peak and all others in a larger
extinction feature (see figure 3)
52- 59 A8 --- A07 Alves et al. 2007 core(s) (1)
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Note (1): Core number from the catalog of Alves et al. 2007 (A07;
Cat. J/A+A/462/L17; <[ALL2007] NNN> in Simbad); 33 cores from the A07
catalog are not included here because they either had no associated
C18O(1-0) emission or the C18O(1-0) emission was not in the range
2<vLSR<8km/s. Because of the differences in the way the cores were
extracted from the extinction image and the fact that we merged or
separated the extinction based on the associated C18O(1-0) emission,
many of the cores from A07 are listed multiple times in our catalog.
To be associated with a core in the current catalog, we require the
cores of A07 to have more than 20 pixels contained within the boundary
of the new core. This criteria was necessary to prevent entries where
the cores within the two catalogs overlapped only at the very edges.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 05-Jul-2011