J/A+A/582/A91 NGC 4418 ALMA mm-wave spectral scan (Costagliola+, 2015)
Exploring the molecular chemistry and excitation in obscured luminous infrared
galaxies: An ALMA mm-wave spectral scan of NGC 4418.
Costagliola F., Sakamoto K., Muller S., Martin S., Aalto S., Harada N.,
van der Werf P., Viti S., Garcia-Burillo S., Spaans M.
<Astron. Astrophys. 582, A91 (2015)>
=2015A&A...582A..91C 2015A&A...582A..91C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Interferometry ; Interstellar medium
Keywords: galaxies: abundances - galaxies: ISM - galaxies: nuclei -
galaxies: active - galaxies: individual: NGC 4418
Abstract:
Extragalactic observations allow the study of molecular chemistry and
excitation under physical conditions which may differ greatly from
what found in the Milky Way. The compact, obscured nuclei (CON) of
luminous infrared galaxies (LIRG) combine large molecular columns with
intense infrared (IR), ultra-violet (UV) and X- radiation and
represent ideal laboratories to study the chemistry of the
interstellar medium (ISM) under extreme conditions.
To obtain for the first time a multi-band spectral scan of a LIRG, in
order to derive the molecular abundances and excitation, to be
compared to other Galactic and extragalactic environments.
We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418,
spanning a total of 70.7GHz in bands 3, 6, and 7. We use a combined
local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum
in order to identify the molecular species and derive column densities
and excitation temperatures. We derive molecular abundances and
compare them with other Galactic and extragalactic sources by means of
a principal component analysis.
Description:
Wide-band mm-wave spectral scan of NGC4418, observed by ALMA in Cycle
0, between April 2012 and January 2013. The spectrum was extracted
from the visibilities with the CASA routine UVMULTIFITS (Marti-Vidal
et al., 2014A&A...563A.136M 2014A&A...563A.136M), assuming a point source.
Objects:
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RA (2000) DE Designation(s)
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12 26 54.63 -00 52 39.5 NGC 4418 = LEDA 40762
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
scan.dat 32 4429 Spectrum of NGC4418
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Byte-by-byte Description of file: scan.dat
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Bytes Format Units Label Explanations
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4- 16 E13.8 GHz Freq Sky frequency
20- 32 E13.8 Jy S Flux density
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Acknowledgements:
Francesco Costagliola, costagli(at)iaa.es
(End) Patricia Vannier [CDS] 03-Jul-2015