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J/A+A/604/A52       B213 filament 150 and 260GHz emission maps   (Bracco+, 2017)

Probing changes of dust properties along a chain of solar-type prestellar and protostellar cores in Taurus with NIKA. Bracco A., Palmeirim P., Andre P., Adam R., Ade P., Bacmann A., Beelen A., Benoeet A., Bideaud A., Billot N., Bourrion O., Calvo M., Catalano A., Coiffard G., Comis B., D'Addabbo A., Desert F.-X., Didelon P., Doyle S., Goupy J., Konyves V., Kramer C., Lagache G., Leclercq S., Macias-Perez J.F., Maury A., Mauskopf P., Mayet F., Monfardini A., Motte F., Pajot F., Pascale E., Peretto N., Perotto L., Pisano G., Ponthieu N., Reveret V., Rigby A., Ritacco A., Rodriguez L., Romero C., Roy A., Ruppin F., Schuster K., Sievers A., Triqueneaux S., Tucker C., Zylka R. <Astron. Astrophys. 604, A52 (2017)> =2017A&A...604A..52B (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium Keywords: dust, extinction - ISM: structure - stars: protostars - stars: formation - ISM: individual objects: B213 in Taurus Abstract: The characterization of dust properties in the interstellar medium (ISM) is key for understanding the physics and chemistry of star formation. Mass estimates are crucial to determine gravitational collapse conditions for the birth of new stellar objects in molecular clouds. However, most of these estimates rely on dust models that need further observational constraints to capture the relevant parameters variations depending on the local environment: from clouds to prestellar and protostellar cores. We present results of a new study of dust emissivity changes based on millimeter (mm) continuum data obtained with the NIKA camera at the IRAM-30m telescope. Observing dust emission at 1.15mm and 2mm allows us to constrain the dust emissivity index, β, in the Rayleigh-Jeans tail of the dust spectral energy distribution (SED) far from its peak emission, where the contribution of other parameters (i.e. dust temperature) is more important. Focusing on the Taurus molecular cloud, one of the most famous low-mass star-forming regions in the Gould Belt, we analyze the emission properties of several distinct objects in the B213 filament. This sub-parsec size region is of particular interest since it is characterized by the presence of a collection of evolutionary stages of early star formation: three prestellar cores, two Class-0/I protostellar cores and one Class-II object. We are therefore able to compare dust properties among a sequence of sources that likely derive from the same parent filament. By means of the ratio of the two NIKA channel-maps, we show that in the Rayleigh-Jeans approximation, βRJ varies among the objects: it decreases from prestellar cores (βRJ∼2) to protostellar cores (βRJ∼1) and the Class-II object (βRJ∼0). For one prestellar and two protostellar cores, we produce a robust study using available Herschel data to constrain the dust temperature of the sources. By using the Abel transform inversion technique we get accurate radial temperature profiles that allow us to obtain radial β profiles. We find systematic spatial variations of β in the protostellar cores that is not observed in the prestellar core. While in the former case β decreases toward the center (with β varying between 1 and 2), in the latter it remains constant (β=2.4±0.3). Moreover, the dust emissivity index appears anticorrelated with the dust temperature. We discuss the implication of these results in terms of dust grain evolution between pre- and protostellar cores. Description: We present the continuum emission maps at 150 and 260GHz of the B213 filament in the Taurus molecular complex obtained with the NIKA camera at IRAM 30m. Observations were performed during the first NIKA open pool, in February 2014, and are presented in the paper. The maps FWHM angular resolution is 24" (see Fig. 1). Due to the scanning strategy, the noise rms is relatively constant in the central part of maps but rapidly increase towards the edge. Scales larger than 2' are filtered during the data reduction. The image coordinates can be found in the FITS header. Three maps per frequency are provided: flux density, noise, and time-per-pixel. Units are MJy/sr and second, respectively. Objects: ----------------------------------------- RA (2000) DE Designation(s) ----------------------------------------- 04 20 51 +27 16.3 B213 = Barnard 213 ----------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 182 2 List of datacubes fits/* 0 2 Individual fits datacubes
See also: J/A+A/554/A55 : C18O(1-0) and N2H+(1-0) in L1495/B213 (Hacar+, 2013) J/A+A/574/A104 : Dense cores in L1495/B213 complex (Tafalla+, 2015) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 22 I3 --- Nx Number of pixels along X-axis 24- 26 I3 --- Ny Number of pixels along Y-axis 28 I1 --- Nz Number of slices 30- 32 I3 Kibyte size Size of FITS file 34- 61 A28 --- FileName Name of FITS file, in subdirectory fits 63-182 A120 --- Title Title of the FITS file
Acknowledgements: Andra Bracco, andrea.bracco(at)cea.fr
(End) Patricia Vannier [CDS] 05-Jul-2017
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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