J/A+A/607/A43 NGC 4418/VV 655 HI images (Varenius+, 2017)
Atomic hydrogen bridge fueling NGC 4418 with gas from VV 655.
Varenius E., Costagliola F., Kloeckner H.-R., Aalto S., Spoon H.,
Marti-Vidal I., Conway J.E., Privon C., Koenig S.
<Astron. Astrophys. 607, A43 (2017)>
=2017A&A...607A..43V 2017A&A...607A..43V (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; H I data
Keywords: galaxies: interactions - galaxies: irregular - galaxies: starburst -
quasars: individual: NGC4418 -galaxies: individual: VV655
Abstract:
The galaxy NGC4418 harbours a compact (<20pc) core with a very high
bolometric luminosity (∼1011L☉). As most of the galaxy's
energy output comes from this small region, it is of interest to
determine what fuels this intense activity. An interaction with the
nearby blue irregular galaxy VV655 has been proposed, where gas
aquired by NGC4418 could trigger intense star formation and/or black
hole accretion in the centre.
We aim to constrain the interaction hypothesis by studying neutral
hydrogen structures which could reveal tails and debris connecting
NGC4418 to the nearby galaxy VV655.
We present observations at 1.4GHz with the Very Large Array (VLA) of
radio continuum as well as emission and absorption from atomic
hydrogen. Gaussian distributions are fitted to observed HI emission
and absorption spectra.We estimate the star formation rate (SFR) of
NGC4418 and VV655 from the 1.4GHz radio emission and compare with
estimates from archival 70um Herschel observations.
Description:
We present data from the VLA taken in D configuration in project AS748
(PI: H. Spoon) on 2003-03-21 with 5.3h on source. The parrallel hands
(RR,LL) were correlated with phase centre
R.A. 12:26:59.750 and Dec. -00:53:31.50 and the data stored in the
archive with time resolution of 30 seconds and spectral resolution of
48.8kHz per channel. The total bandwidth covered 63 channels,
centered on 1.41017559GHz.
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
12 27 04.53 -00 54 21.1 VV 655 = LEDA 40790
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 133 2 List of fits files
fits/* . 2 Individual fits files
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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- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 31 I2 --- Nz ? Number of slices
33- 58 A26 --- Obs.Date Observation date
60- 66 F7.5 GHz Freq Observed frequency or lower value of
frequency interval for the datacube
68- 74 F7.5 GHz BFreq ? Upper value of frequency interval for the
datacube
76- 82 F7.1 Hz dFreq ? Frequency resolution for the datacube
84- 88 I5 Kibyte size Size of FITS file
90-110 A21 --- FileName Name of FITS file, in subdirectory fits
112-133 A22 --- Title Title of the FITS file
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Acknowledgements:
Eskil Varenius, eskil.varenius(at)chalmers.se
(End) Patricia Vannier [CDS] 12-Sep-2017