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J/ApJ/606/929       IR to mm observations of IRAS 18317-0757     (Hunter+, 2004)

IRAS 18317-0757: a cluster of embedded massive stars and protostars. Hunter T.R., Zhang Q., Sridharan T.K. <Astrophys. J., 606, 929-942 (2004)> =2004ApJ...606..929H
ADC_Keywords: Infrared sources ; Interstellar medium Keywords: infrared: stars - stars: formation - ISM: individual (AFGL 2194, G23.95+0.15, IRAS 18317-0757) Abstract: We present high-resolution, multiwavelength-continuum, and molecular-line images of the massive star forming region IRAS 18317-0757. The global infrared through millimeter spectral energy distribution can be approximated by a two-temperature model (25 and 63K) with a total luminosity of approximately log(L/L)=5.2. Previous submillimeter imaging resolved this region into a cluster of five dust cores, one of which is associated with the ultracompact HII region G23.955+0.150, and another with a water maser. In our new 2.7mm continuum image obtained with BIMA, only the UCHII region is detected, with total flux and morphology in good agreement with the free-free emission in the VLA centimeter-wave maps. For the other four objects, the nondetections at 2.7mm and in the MSX mid-infrared bands are consistent with cool dust emission with a temperature of 13-40K and a luminosity of 1000-40000L. By combining single-dish and interferometric data, we have identified over two dozen virialized C18O cores in this region that contain ∼40% of the total molecular gas mass present. Description: With the Berkeley-Illinois-Maryland Association (BIMA) Millimeter Array, IRAS 18317-0757 was simultaneously observed in 110GHz continuum and C18O (1-0). The continuum bandwidth was 600MHz. The spectral resolution for the line data was 0.2MHz (0.53km/s). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 88 7 Observed emission properties of submillimeter clumps table5.dat 77 26 Position and mass of C18O (1-0) clumps table7.dat 23 44 Stars detected in all three 2MASS bands
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Source Source name (1) 10- 11 I2 h RAh ? Right ascension (J2000.0) 13- 14 I2 min RAm ? Right ascension (J2000.0) 16- 19 F4.1 s RAs ? Right ascension (J2000.0) 21 A1 --- DE- Declination sign (J2000.0) 22- 23 I2 deg DEd ? Declination (J2000.0) 25- 26 I2 arcmin DEm ? Declination (J2000.0) 28- 29 I2 arcsec DEs ? Declination (J2000.0) 31- 33 I3 Jy S350um Flux density at 350µm, within 22" aperture 35- 36 I2 Jy e_S350um rms uncertainty on S350um 38 A1 --- l_S2.7mm Limit flag on S2.7mm (upper limits are 3σ) 39- 43 F5.3 Jy S2.7mm Flux density at 2.7mm, within 22" aperture 45- 48 F4.2 Jy e_S2.7mm ? rms uncertainty on S2.7mm 50- 53 I4 solMass Mass Mass (2) 55- 57 I3 solMass e_Mass rms uncertainty on Mass 59- 63 F5.2 [cm-2] logNH ? Hydrogen column density (3) 65- 68 F4.2 [cm-2] e_logNH ? rms uncertainty on logNH 70- 72 I3 --- AV [52/144]? Extinction in V band, in magnitudes, AV=NH/(4*1021) (4) 74- 77 F4.1 mag AK ? Extinction in K band, AK=0.112*AV (4)
Note (1): Clumps are identified as [HCW2000] IRAS 18317-0757 SMM N in Simbad. "Total" represents the total flux including extended emission within dotted region of Fig.2. Note (2): Mass, Assuming T=25K and grain emissivity Q=1.0x10-4 at 350um (Hildebrand, 1983QJRAS..24..267H) Note (3): Hydrogen column density Assuming uniform emission of diameter 11" (0.25pc). Note (4): Extinction to a star at the center of the dust core, i.e., half the column density, reduced by a factor of 2 to more accurately estimate the extinction toward a young star at the center of the clump, rather than behind it.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 2 I2 --- C18O Sequential number, [HZS2004] C18O NN 4- 5 I2 h RAh Right ascension (J2000.0) 7- 8 I2 min RAm Right ascension (J2000.0) 10- 15 F6.3 s RAs Right ascension (J2000.0) 17 A1 --- DE- Declination sign (J2000.0) 18- 19 I2 deg DEd Declination (J2000.0) 21- 22 I2 arcmin DEm Declination (J2000.0) 24- 28 F5.2 arcsec DEs Declination (J2000.0) 30- 33 F4.1 Jy.km/s Emi Emission 35- 39 F5.2 [cm-2] logN(C18O) C18O column density 41- 44 F4.1 mag AK Extinction in K band 46- 48 I3 solMass MH2 H2 mass 50- 53 F4.1 km/s Vel Velocity 55- 57 F3.1 km/s e_Vel rms uncertainty on Vel 59- 61 F3.1 Jy PFlux Peak flux, in Jy/beam 63- 65 F3.1 Jy e_PFlux rms uncertainty on PFlux, in Jy/beam 67- 69 F3.1 km/s Width Line width 71- 73 F3.1 km/s e_Width rms uncertainty on Width 75- 77 I3 solMass Mvirial Virial mass (1)
Note (1): --------------------------- Emission MH2 Mvirial --------------------------- Total clump component 352 2930 2915 Extended component 527 4410 Total emission 879 7340 ---------------------------
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Star Star number given in Figure 12 and 13, [HZS2004] Star NNN 5 A1 --- f_Star [a] Flag on Star (1) 7- 22 A16 --- 2MASS The 2MASS PSC name
Note (1): a: Stars with AV>10, according to the color-color diagram shown in Figure 12.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 02-Jul-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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