J/A+A/606/A142 L1544 1.2 and 2mm emission maps (Chacon-Tanarro+, 2017)
Search for grain growth towards the center of L1544.
Chacon-Tanarro A., Caselli P., Bizzocchi L., Pineda J.E., Harju J.,
Spaans M., Desert F.-X.
<Astron. Astrophys. 606, A142 (2017)>
=2017A&A...606A.142C 2017A&A...606A.142C (SIMBAD/NED BibCode)
ADC_Keywords: Radio continuum ; Molecular clouds
Keywords: ISM: clouds - ISM: individual objects: L1544 - ISM: dust, extinction -
opacity - stars: formation
Abstract:
In dense and cold molecular clouds dust grains are surrounded by thick
icy mantles. It is however not clear if dust growth and coagulation
take place before the switch-on of a protostar. This is an important
issue, as the presence of large grains may affect the chemical
structure of dense cloud cores, including the dynamically important
ionization fraction, and the future evolution of solids in
protoplanetary disks. To study this further, we focus on L1544, one of
the most centrally concentrated pre-stellar cores on the verge of star
formation, and with a well-known physical structure. We observed L1544
at 1.2 and 2mm using NIKA, a new receiver at the IRAM 30 m telescope,
and we used data from the Herschel Space Observatory archive. We find
no evidence of grain growth towards the center of L1544 at the
available angular resolution. Therefore, we conclude that single dish
observations do not allow us to investigate grain growth towards the
pre-stellar core L1544 and high sensitivity interferometer
observations are needed. We predict that dust grains can grow to 200um
in size toward the central ∼300au of L1544. This will imply a dust
opacity change by a factor of ∼2.5 at 1.2mm, which can be detected
using the Atacama Large Millimeter and submillimeter Array (ALMA) at
different wavelengths and with an angular resolution of 2".
Description:
Millimeter observations of the pre-stellar core L1544 are presented.
These observations were carried out at the IRAM 30m telescope,
located at Pico Veleta (Spain) using the New IRAM KID Array (NIKA).
The project number is 151-13. A region of 3°x3° was mapped
using the Lissajous pattern at 1.2 and 2mm. The main beam widths are
12.5-arcsec at 1.2mm and 18.5 arcsec at 2mm. The KID array has a
field-of-view is 1.8' at 1.2mm and 2.0' at 2mm.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
05 04 18 +25 11.1 L1544 = LDN 1544
-----------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 81 2 List of fitd maps
fits/* . 2 Individual fits maps
--------------------------------------------------------------------------------
See also:
J/A+A/555/A109 : 14N/15N isotopic ratio in L1544 (Bizzocchi+, 2013)
J/A+A/606/A82 : Observed chemical structure of L1544 (Spezzano+, 2017)
J/ApJ/833/176 : The magnetic field of L1544. I. NIR data (Clemens+, 2016)
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- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 28 I3 Kibyte size Size of FITS file
30- 53 A24 --- FileName Name of FITS file, in subdirectory fits
55- 81 A27 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Ana Chacon-Tanarro, achacon(at)mpe.mpg.de
(End) Ana Chacon-Tanarro [MPE, Germany], Patricia Vannier [CDS] 10-Jul-2017