J/ApJ/668/1042 Dense cores in Perseus molecular cloud (Kirk+, 2007)
Dynamics of dense cores in the Perseus molecular cloud.
Kirk H., Johnstone D., Tafalla M.
<Astrophys. J., 668, 1042-1063 (2007)>
=2007ApJ...668.1042K 2007ApJ...668.1042K
ADC_Keywords: Molecular clouds ; Infrared sources ; Millimetric/submm sources
Keywords: infrared: ISM - ISM: individual (Perseus) - ISM: structure -
stars: formation - submillimeter
Abstract:
We survey the kinematics of over 150 candidate (and potentially
star-forming) dense cores in the Perseus molecular cloud with pointed
N2H+(1-0) and simultaneous C18O(2-1) observations. Our detection
rate of N2H+ is 62%, rising to 84% for SCUBA-selected targets. In
agreement with previous observations, we find that the dense N2H+
targets tend to display nearly thermal line widths, particularly those
that appear to be starless (using Spitzer data), indicating that
turbulent support on the small scales of molecular clouds is minimal.
For those N2H+ targets that have an associated SCUBA dense core,
we find that their internal motions are more than sufficient to
provide support against the gravitational force on the cores.
Description:
We made pointed observations of the 157 targets using the 30m IRAM
telescope in Pico Veleta, Spain. We observed N2H+(1-0) in both
polarizations using the (AB) 100GHz receivers and simultaneously
observed C18O(2-1) in both polarizations using the (CD) 230GHz
receivers, in both cases utilizing frequency switching
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 52 157 Target Properties
table3.dat 56 425 Parameters of spectral fitting for N2H+
table4.dat 50 472 Parameters of Spectral Fitting for C18O
table6.dat 78 87 Properties of the submillimeter cores identified
in the Perseus SCUBA map with 3" pixels
--------------------------------------------------------------------------------
See also:
J/ApJ/646/1009 : Structures of dust in Perseus molecular cloud (Kirk+, 2006)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [KJT2007] Sequential number
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 14 F4.1 s RAs Right ascension (J2000.0)
16 A1 --- DE- Declination sign (J2000.0)
17- 18 I2 deg DEd Declination (J2000.0)
20- 21 I2 arcmin DEm Declination (J2000.0)
23- 26 F4.1 arcsec DEs Declination (J2000.0)
28 A1 --- Sel [PES] Selection method (1)
30- 32 A3 --- Cross? [Yes No] Were offset positions observed?
34- 35 I2 --- SMM ? SCUBA core reference number (see table6,
[KJT2007] SMM NN in Simbad)
37- 41 F5.2 Jy Flux Total SCUBA flux at 850um within the IRAM
beam (2)
43- 44 I2 --- [JJK2007] ? Spitzer protostar reference number (from
Jogensen et al. 2007ApJ...656..293J 2007ApJ...656..293J)
46- 47 I2 --- EReg ? Extinction Region number (from Paper I,
Kirk et al., Cat. J/ApJ/646/1009)
[KJD2006] EC NN in Simbad
49- 52 F4.1 mag AV Mean extinction within the IRAM beam
--------------------------------------------------------------------------------
Note (1): Target selection based as follows:
S = on SCUBA cores
P = on Palomar plate candidates
E = on 2MASS extinction structures
Note (2): derived from the 6" map of Paper I, Kirk et al., J/ApJ/646/1009.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [KJT2007] Source identification number (1)
5- 6 I2 --- oRA Offset in Right Ascension (2)
8- 9 I2 --- oDE Offset in Declination (2)
11- 15 F5.2 km/s Vel ? CLASS derived centroid velocity (3)
17- 20 F4.2 km/s sigma ? CLASS derived velocity dispersion (FWHM)
22- 24 I3 m/s e_sigma ? Error in sigma
26- 30 F5.2 --- tau ? CLASS derived optical depth
32- 36 F5.2 --- e_tau ? Error in Depth
38- 41 F4.2 K Brms CLASS derived baseline rms
43- 46 F4.2 K Mrms ? CLASS derived model rms
48- 52 F5.2 K.km/s Int ? Integrated intensity (4)
54- 56 A3 --- Good [yes no] Was the fit judged to be good?
--------------------------------------------------------------------------------
Note (1): See Table 1 for the locations of the targets.
Note (2): Measured in units of the beam (25arcsec).
Note (3): The error was similar in all cases with a mean and standard
deviation of 8±8m/s.
Note (4): Computed using the tdv function in CLASS. See 3.1 for further details.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [KJT2007] Source identification number (1)
5- 6 I2 --- oRA Offset in Right Ascension (2)
8- 9 I2 --- oDE Offset in Declination (2)
11- 15 F5.2 km/s Vel ? CLASS derived centroid velocity (3)
17- 20 F4.2 km/s sigma ? CLASS derived velocity dispersion (FWHM)
22- 24 I3 m/s e_sigma ? Error in DelV
26- 30 F5.2 K Tpeak ? CLASS derived peak intensity (T*A units)
32- 36 F5.2 K.km/s Int ? CLASS derived integrated intensity
38- 41 F4.2 K Brms CLASS derived baseline rms
43- 46 F4.2 K Mrms ? CLASS derived model rms
48- 50 A3 --- Good Was the fit judged to be good?
--------------------------------------------------------------------------------
Note (1): See Table 1 for the locations of the targets.
Note (2): Measured in units of the beam (25arcsec).
Note (3): The error was similar in all cases with a mean and standard
deviation of 16±15m/s.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- SMMJ Name (HHMMSS+DDMMm),
[KJT2007] SMM JHHMMmm+DDMMm in Simbad
14- 15 I2 --- SMM Submillimeter cores identified reference
number, [KJT2007] SMM NN in Simbad
17- 18 I2 h RAh Right ascension (J2000.0)
20- 21 I2 min RAm Right ascension (J2000.0)
23- 26 F4.1 s RAs Right ascension (J2000.0)
28 A1 --- DE- Declination sign (J2000.0)
29- 30 I2 deg DEd Declination (J2000.0)
32- 33 I2 arcmin DEm Declination (J2000.0)
35- 38 F4.1 arcsec DEs Declination (J2000.0)
40- 42 F3.1 Jy Sp850 Peak flux at 850um in Jy/beam (2)
44- 48 F5.2 Jy S850 Total flux at 850um (2)
50- 53 F4.1 arcsec Reff Effective radius (2)
55- 58 F4.2 --- Conc Concentration index
60- 61 I2 K TBE BE temperature (3)
63- 66 F4.2 [cm-3] log(n0) Central number density (3)
68- 71 F4.2 cm3/K Pext/k External pressure (3)
73- 75 A3 --- Fit [Yes No] secure fit? (4)
77- 78 I2 --- [JJK2007] ? Associated protostar (5)
--------------------------------------------------------------------------------
Note (2): derived from clfind (Williams et al. 1994, Cat. J/ApJ/428/693).
The beam size is 15.7" for the peak flux.
Note (3): derived from Bonnor-Ebert (BE) modeling described in
section 5 of paper I (2006ApJ...646.1009K 2006ApJ...646.1009K)
Note (4): See text for description of which submillimeter core
identifications are considered to be secure.
Note (5): The reference number of any associated Spitzer protostar from the
catalog of Jorgensen et al. (2007ApJ...656..293J 2007ApJ...656..293J). Note that if more
than one protostar is considered to be associated (within 15"), only
the closest one is listed.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Kirk et al., Paper I 2006ApJ...646.1009K 2006ApJ...646.1009K, Cat. J/ApJ/646/1009
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 03-Jan-2010