J/A+A/613/A42 M-3.8+0.9 molecular cloud 3mm datacubes (Riquelme+ 2018)
The footpoints of the giant molecular loops in the Galactic center region.
Riquelme D., Amo-Baladron A., Martin-Pintado J., Mauersberger R.,
Martin S., Burton M., Cunningham M., Jones P., Menten K.M., Bronfman L.,
Guesten R.
<Astron. Astrophys. 613, A42 (2018)>
=2018A&A...613A..42R 2018A&A...613A..42R (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Molecular clouds
Keywords: ISM: molecules - Galaxy: center - ISM: clouds
Abstract:
We aim to reveal the morphology, chemical composition, kinematics and
to establish the main processes prevalent in the gas at the footpoints
of the giant molecular loops (GMLs) in the Galactic center region.
Using the 22-m Mopra telescope, we mapped the M-3.8+0.9 molecular
cloud, placed at the footpoints of a giant molecular loop, in 3-mm
range molecular lines. To derive the molecular hydrogen column
density, we also observed the 13CO (2-1) line at 1mm using the 12-m
APEX telescope. From the 3 mm observations 12 molecular species were
detected, namely HCO+, HCN, H13CN, HNC, SiO, CS, CH3OH, N2H+,
SO, HNCO, OCS, and HC3N.
Maps revealing the morphology and kinematics of the M-3.8+0.9
molecular cloud in different molecules are presented. We identify six
main molecular complexes. We derive fractional abundances in 11
selected positions of the different molecules assuming local
thermodynamical equilibrium.
Most of the fractional abundances derived for the M-3.8+0.9 molecular
cloud are very similar over the whole cloud. However, the fractional
abundances of some molecules show significant difference with respect
to those measured in the central molecular zone (CMZ). The abundances
of the shock tracer SiO are very similar between the GMLs and the CMZ.
The methanol emission is the most abundant species in the GMLs. This
indicates that the gas is likely affected by moderate ∼30km/s or
even high velocity (50km/s) shocks, consistent with the line profile
observed toward one of the studied position. The origin of the shocks
is likely related to the flow of the gas throughout the GMLs towards
the footpoints.
Description:
We mapped the M-3.8+0.9 molecular cloud placed at the footpoints of a
giant molecular loop, in 3-mm range molecular lines using Mopra
telescope, and the 13CO (2-1) line at 1 mm using the 12-m Atacama
Pathfinder EXperiment (APEX) telescope.
The Mopra observations were performed during September 2008 and August
2009. We used the digital mode filter bank MOPS in broadband mode,
covering 8GHz of bandwidth simultaneously in four 2.2GHz sub-bands,
each of them with 8192 channel spaced by 0.27MHz. Two polarizations
were measured simultaneously.
We produce one data cube per detected molecule. The final spatial
resolution of the data cubes is between 49 arcsec and 51 arcsec at
115 and 86GHz respectively.
The size of the pixel is 15 arcsec. The spectral resolution of the
data is 269.5kHz (0.94-0.78km/s). The data is presented in T*a
(K). The APEX observations were carried out on 24 June, and 1, 2, and
3 July 2014 under the APEX project code M-093.F-008-2014 using the
APEX-1 (SHIFI) receiver and the eXtended bandwidth Fast Fourier
Transform Spectrometer (XFFTS) backend.
The data were regridded in equatorial coordinates and then converted
to Galactic coordinates for comparison with the Mopra data using
standard CLASS routines. The pixel size is 13.8 arcsec. The spatial
resolution is 30.1 arcsec and the spectral resolution is 299.8kHz
(1.03km/s). The data is presented in Tmb (K).
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------
17 32 54 -31 43 21 M-3.8+0.9 = [RBM2010] M-3.8+0.9
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 106 14 List of the available data cubes
fits/* . 14 Individual data cubes
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Name of the source
12- 18 F7.3 deg GLong Galactic Longitude
20- 24 F5.3 deg GLat Galactic Latitude
27- 33 F7.3 GHz RestFreq Rest Frequency
35- 37 I3 --- Nx Number of pixels along X-axis
39- 41 I3 --- Ny Number of pixels along Y-axis
43- 46 I4 --- Nz Number of slices
49- 55 A7 K Scale Intensity Scale
57- 80 A24 --- Title Title of the FITS file
82-106 A25 --- FileName Name of FITS file, in subdirectory fits
--------------------------------------------------------------------------------
Acknowledgements:
Denise Riquelme, riquelme(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 26-Jan-2018