J/AJ/138/1380 Dust clumps in the Galactic Plane (Matthews+, 2009) ================================================================================ Looking through the Galactic Plane: imaging cold dust toward l = 44{deg}. Matthews H., Kirk H., Johnstone D., Weferling B., Cohen M., Jenness T., Evans A., Davis G., Dent W.R.F., Fuller G., Jackson J.M., Rathborne J., Richer J., Simon R. =2009AJ....138.1380M ================================================================================ ADC_Keywords: Interstellar medium ; Molecular clouds ; Galactic plane ; Spectra, millimetric/submm Keywords: dust, extinction - ISM: clouds - ISM: molecules - ISM: structure - submillimeter Abstract: We present imaging observations of continuum emission from interstellar dust at 850 and 1200um of a section of the Galactic Plane covering 2deg^2^ centered at l=44{deg}. Complementary jiggle-mapping and fast-scanning techniques were used, respectively, at these two wavelengths. The mapped area includes the well-known star formation regions W49 and G45.1/45.5. Using an automated clump-finding routine, we identify 132 compact 850um emission features within the region above a completeness level of about 200mJy/beam. The positions of the latter objects were used to determine fluxes from the 1200um image. Spectral line data were subsequently obtained with the same observing beamwidth as at 850um for almost half of the objects; these were either imaged in the ^13^CO (3-2) line, or basic characteristics determined using the ^12^CO (3-2) transition. We use these data, supplemented by existing ^13^CO (1-0) and HI survey data, to determine distances and hence derive masses for the dust clump ensemble, assuming a uniform dust temperature of 15K. From these data we find that the number-mass relationship for clumps in the field is similar to that found for individual star-forming regions. Description: The 850um observations were carried out at the James Clerk Maxwell Telescope, situated close to the summit of Mauna Kea, Hawaii, using the Submillimeter Common-User Bolometer Array (SCUBA) receiver during two periods between 2003 July 29 and August 1 and 2004 March 30 and April 5. In a companion study to the 850um imaging, 1200um observations were obtained using SIMBA (Sest IMaging Bolometer Array), a 37-element bolometer array mounted on the SEST 15m antenna, and were carried out during 2003 August. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 69 132 Clumps identified in the 850um image table6.dat 36 132 Distance determinations obtained from ^13^CO(1-0) and HI data table7.dat 21 132 Clump masses based on clump and cloud distance determinations table8.dat 68 132 Sources of emission probably associated with dust clumps -------------------------------------------------------------------------------- See also: J/ApJS/195/14 : The Bolocam Galactic Plane Survey (BGPS). V. (Schlingman+, 2011) J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010) J/ApJS/182/131 : Molecular clouds and clumps in the GRS (Rathborne+, 2009) J/ApJ/699/1153 : Kinematic distances to GRS molecular clouds (Roman-Duval+, 2009) J/ApJS/175/277 : Submillimeter-Continuum SCUBA detections (Di Francesco+, 2008) J/ApJ/626/887 : HI clouds in Southern Galactic Plane Survey (Kavars+, 2005) J/ApJS/155/577 : H2O masers in W49 North and Sagittarius B2 (McGrath+, 2004) J/ApJ/559/307 : Sub-mm mapping in Orion B molecular cloud (Johnstone+, 2001) J/ApJ/428/693 : Rosette Nebula and Maddalena Cloud structures (Williams+ 1994) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Clump number (<[MKJ2009] NNN> in Simbad) 5- 17 A13 --- [MKJ2009] Name (GLL.lll+B.bbb) (1) 19- 20 I2 h RAh Hour of right ascension (J2000) (2) 22- 23 I2 min RAm Minute of right ascension (J2000) (2) 25- 28 F4.1 s RAs Second of right ascension (J2000) (2) 30 A1 --- DE- Sign of declination (J2000) (2) 31- 32 I2 deg DEd Degree of declination (J2000) (2) 34- 35 I2 arcmin DEm Arcminute of declination (J2000) (2) 37- 38 I2 arcsec DEs Arcsecond of declination (J2000) (2) 40- 44 F5.2 Jy P850 850um peak flux of the clump in Jy/beam unit (3) 46- 51 F6.2 Jy S850 SCUBA/JCMT 850um total flux of the clump (3) 53- 56 F4.1 arcsec Reff Effective radius of the clump (3) 58- 62 F5.2 Jy P1200 Peak flux at 1200um in Jy/beam unit (4) 64- 69 F6.2 Jy S1200 SIMBA/SEST total flux at 1200um (4) ------------------------------------------------------------------------------- Note (1): Name formed from equivalent Galactic coordinates, accurate to approximately 4". Note (2): Position of peak surface brightness within the clump at 850um (positional accuracy about 4"). Note (3): Peak flux, total flux, and effective radius of the clumps as determined by clfind (Williams et al. 1994, Cat. J/ApJ/428/693). The absolute flux calibration is uncertain at a level of about 20%. The effective radius has not been deconvolved from the telescope beam. Note (4): Peak flux and total flux at 1200um determined using the 850um clump locations. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Clump number (as in table 2) 5- 9 F5.3 K Pk Peak ^13^CO(1-0) intensity 11- 16 F6.2 km/s Vlsr Local standard of rest velocity 18 A1 --- n_Dist [N/F] Near/Far clump distance resolution 20- 24 F5.2 kpc Dist Clump distance based on clump velocity 26- 28 I3 --- HI ?=0 HI catalogue cloud number (maintained locally at Boston University) 30 A1 --- n_Dist1 [N/F/0] Near/Far distance resolution based on HI cloud data 32- 36 F5.2 kpc Dist1 ?=0 Cloud distance derived from HI cloud data -------------------------------------------------------------------------------- Byte-by-byte Description of file: table7.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Clump number 5- 12 F8.1 Msun Mclp Clump mass derived from the clump distance (5) 14- 21 F8.1 Msun Mcld ? Clump mass derived from the cloud distance (6) ------------------------------------------------------------------------------- Note (5): Clump mass derived from the clump distance as listed in Table 6. Note (6): Clump mass derived from the cloud distance as listed in Table 6. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table8.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq Clump number 5- 68 A64 --- Assoc Association(s) (7) ------------------------------------------------------------------------------- Note (7): Other sources of emission probably associated with this dust clump, within a radius of 1 arcmin from the dust clump position. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Emmanuelle Perret [CDS] 24-Jan-2012