J/A+A/644/A133 New APEX-SEPIA660 observations in OMC-1 (Hacar+, 2020)
APEX-SEPIA660 Early Science: gas at densities above 107 cm-3 towards OMC-1.
Hacar A., Hogerheijde M. R., Harsono D., Portegies Zwart S., De Breuck C.,
Torstensson K., Boland W., Baryshev A.M., Hesper R., Barkhof J., Adema J.,
Bekema M.E., Koops A., Khudchenko A., Stark R.
<Astron. Astrophys. 644, A133 (2020)>
=2020A&A...644A.133H 2020A&A...644A.133H (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Spectra, millimetric/submm ; Abundances
Keywords: ISM: clouds - ISM: molecules - ISM: structure - submillimeter: ISM
Abstract:
The star-formation rates and stellar densities found in young massive
clusters suggest that these stellar systems originate from gas at
densities of n(H2)>106cm-3. Until today, however, the physical
characterization of this ultra high density material remains largely
unconstrained in observations.
We investigate the density properties of the star-forming gas in the
OMC-1 region located in the vicinity of the Orion Nebula Cluster
(ONC). Methods. We mapped the molecular emission at 652GHz in OMC-1
as part of the APEX-SEPIA660 Early Science.
We detect bright and extended N2H+ (J=7-6) line emission along the
entire OMC-1 region. Comparisons with previous ALMA data of the
(J=1-0) transition and radiative transfer models indicate that the
line intensities observed in this N2H+ (7-6) line are produced by
large mass reservoirs of gas at densities n(H2)>107cm-3.
The first detection of this N2H+ (7-6) line at parsec-scales
demonstrates the extreme density conditions of the star-forming gas in
young massive clusters such as the ONC. Our results highlight the
unique combination of sensitivity and mapping capabilities of the new
SEPIA660 receiver for the study of the ISM properties at high
frequencies.
Description:
Cubes & Integrated intensity (moment 0) maps for N2H+ (7-6) and
C18O (6-5) lines obtained using the new APEX-SEPIA660 receiver
Objects:
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RA (2000) DE Designation(s)
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05 35 14 -05 22 20 OMC-1 = NAME OMC-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 149 4 List of fits files
fits/* . 4 Indifidual fits datacubes and maps
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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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- 30 I3 --- Nz ? Number of slices for the datacubes
32- 40 F9.2 m/s bVRAD ? Lower value of VRAD interval
for the datacubes
42- 48 F7.1 m/s BVRAD ? Upper value of VRAD interval
for the datacubes
50- 55 F6.2 m/s dVRAD ? VRAD resolution for the datacubes
57- 61 I5 Kibyte size Size of FITS file
63- 89 A27 --- FileName Name of FITS file, in subdirectory fits
91-149 A59 --- Title Title of the FITS file
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Acknowledgements:
Alvaro Hacar, alvaro.hacar(at)univie.ac.at
This work is part of the ORION-4D project (PI: A. Hacar).
See more information in https://sites.google.com/site/orion4dproject
(End) Patricia Vannier [CDS] 08-Dec-2020