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J/A+A/597/A85       NGC3627S and NGC3627N CO(1-0) data cubes    (Beuther+, 2017)

Interactions of the Galactic bar and spiral arm in NGC 3627. Beuther H., Meidt S., Schinnerer E., Paladino R., Leroy A. <Astron. Astrophys. 597, A85 (2017)> =2017A&A...597A..85B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Carbon monoxide ; Radial velocities Keywords: stars: formation - galaxy: individual: NGC 3627 - stars: massive - ISM: clouds - ISM: structure Abstract: To gain insight into the expected gas dynamics at the interface of the Galactic bar and spiral arms in our own MilkyWay galaxy, we examine as an extragalactic counterpart the evidence for multiple distinct velocity components in the cold, dense molecular gas populating a comparable region at the end of the bar in the nearby galaxy NGC 3627. We assemble a high resolution view of molecular gas kinematics traced by CO(2-1) emission and extract line-of-sight velocity profiles from regions of high and low gas velocity dispersion. The high velocity dispersions arise with often double-peaked or multiple line-profiles. We compare the centroids of the different velocity components to expectations based on orbital dynamics in the presence of bar and spiral potential perturbations. A model of the region as the interface of two gas-populated orbits families supporting the bar and the independently rotating spiral arms provides an overall good match to the data. An extent of the bar to the corotation radius of the galaxy is favored. Using NGC 3627 as an extragalactic example, we expect situations like this to favor strong star formation events such as observed in our own Milky Way since gas can pile up at the crossings between the orbit families. The relative motions of the material following these orbits is likely even more important for the build up of high density in the region. The surface densities in NGC 3627 are also so high that shear at the bar end is unlikely to significantly weaken the star formation activity. We speculate that scenarios in which the bar and spiral rotate at two different pattern speeds may be the most favorable for intense star formation at such interfaces. Description: Paladino et al. (2008A&A...485..679P) present the PdBI for the first time, however, they focus on the CO(1-0) observations and do not complement the data with short spacing information. The PdBI observations were carried out on March 20, 2005 with 6 antennas in the C configuration. At that time, 1.3 and 2.6mm data could be taken simultaneously, and the observations targeted the CO(1-0) and (2-1) lines, respectively. The two frequencies were centered at 114.997 and 229.88GHz which are the transition rest frequencies at an assumed vlsr of ∼712.6km/s. With four overlapping 160MHz spectral units, the correlator covered 580MHz for each line (corresponding to 1512 and 756km/s for the (1-0) and (2-1) lines, respectively). Bandpass and flux calibration were conducted with 1055+018 and MWC349, and the gains were calibrated with regular observations of 1116+128. To complement the PdBI CO(2-1) data with the missing short spacing information, we used the IRAM 30m single-dish observations from the HERACLES survey (Leroy et al., 2009AJ....137.4670L). These data are available for download at www.mpia.de/HERACLES. The HERACLES CO(2-1) data were further processed in GILDAS/CLASS and finally combined and imaged with the PdBI data within the mapping part of the GILDAS package. Objects: ------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------- 11 20 15.03 +12 59 28.6 NGC 3627 = M 66 ------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 120 2 List of fits datacubes fits/* 0 2 Individual fits datacubes
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- 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 slices 31- 33 I3 km/s b_VRAD Lower value of VRAD interval 35- 37 I3 km/s B_VRAD Upper value of VRAD interval 39 I1 km/s dVRAD VRAD resolution 41- 45 I5 Kibyte size Size of FITS file 47- 73 A27 --- FileName Name of FITS file, in subdirectory fits 75-120 A46 --- Title Title of the FITS file
Acknowledgements: Henrik Beuther, beuther(at)mpia.de
(End) Patricia Vannier [CDS] 22-Sep-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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