J/A+A/694/A87 NGC 3627, NGC 4321, and NGC 6946 [CII] mapping (Kovacic+, 2025)
Full disc [C II] mapping of nearby star-forming galaxies.
SOFIA FIFI/LS observations of NGC 3627, NGC 4321, and NGC 6946.
Kovacic I., Barnes A.T., Bigiel F., De Looze I., Madden S.C.,
Herrera-Camus R., Krabbe A., Baes M., Beck A., Bolatto A.D., Bryant A.,
Coldirt S., Fischer C., Geis N., Iserlohe C., Klein R., Leroy A.,
Looney L.W., Poglitsch A., Sartorio N.S., Vacca W.D., van der Giessen S.,
Nersesian A.
<Astron. Astrophys. 694, A87 (2025)>
=2025A&A...694A..87K 2025A&A...694A..87K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Infrared ; Spectroscopy
Keywords: galaxies: ISM - galaxies: individual: NGC 3627 -
galaxies: individual: NGC 4321 - galaxies: individual: NGC 6946 -
galaxies: photometry - galaxies: star formation
Abstract:
As a major cooling line of interstellar gas, the far-infrared 158um
line from singly ionised carbon [CII] is an important tracer of
various components of the interstellar medium in galaxies across all
spatial and morphological scales. Yet, there is still not a strong
constraint on the origins of [CII] emission.
In this work, we derive the resolved [CII] star formation rate
relation and aim to unravel the complexity of the origin of [CII].
We used the Field-Imaging Far-Infrared Line Spectrometer on board the
Stratospheric Observatory for Infrared Astronomy to map [CII] in three
nearby star-forming galaxies at sub-kiloparsec scales, namely,
NGC 3627, NGC 4321, and NGC 6946, and we compared these [CII]
observations to the galactic properties derived from complementary
data from the literature.
We find that the relationship between the [CII] fine structure line
and star formation rate shows variations between the galaxies as well
as between different environments within each galaxy.
Our results show that the use of [CII] as a tracer for star formation
is much more tangled than has previously been suggested within the
extragalactic literature, which typically focuses on small regions of
galaxies and/or uses large-aperture sampling of many different
physical environments. As found within resolved observations of the
Milky Way, the picture obtained from [CII] observations is complicated
by its local interstellar medium conditions. Future studies will
require a larger sample and additional observational tracers, obtained
on spatial scales within galaxies, in order to accurately disentangle
the origin of [CII] and calibrate its use as a star formation tracer.
Description:
We selected the three star-forming galaxies: NGC 3627, NGC 4321, and
NGC 6946.
SOFIA consisted of a 2.5m telescope carried by a Boeing 747 aircraft
operating at altitudes above most of the atmospheric water vapour and
covered the IR region of the spectrum. Its instrument FIFI-LS featured
two parallel spectral channels with wavelengths of 51-125um, the 'blue
channel', and 115-203um, the ;red channel'. Each channel consisted of
a field of view (FOV) of 5x5 spatial pixels, with a plate scale of
6.14"x6.25" for blue and 12.2"x12.5" for red. This translates into an
FOV of 60"x60" for the red channel and 30"x30" for the blue channel.
The spatial resolution at the observed [CII] 158um line is 15.6", with
a spectral resolution of R=1200.
Objects:
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RA (2000) DE Designation(s)
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11 20 15.02 +12 59 29.4 NGC 3627 = M 66
12 22 54.92 +15 49 20.2 NGC 4321 = M 100
20 34 52.33 +60 09 13.2 NGC 6946 = UGC 11597
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 134 3 List of fits images
fits/* . 3 Individual fits images
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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- 29 I2 --- Nz Number of pixels along Z-axis
31- 49 A19 "datime" Obs.date Observation date
51- 55 I5 Kibyte size Size of FITS file
57-107 A51 --- FileName Name of FITS file, in subdirectory fits
109-134 A26 --- Title Title of the FITS file
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Acknowledgements:
Inja Kovacic, inja.kovacic(at)ugent.be
(End) Patricia Vannier [CDS] 23-Dec-2024