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J/A+A/603/A68   Images of molecular and ionized gas around Sgr A* (Moser+, 2017)

Approaching hell's kitchen: Molecular daredevil clouds in the vicinity of Sagittarius A*. Moser L., Sanchez-Monge A., Eckart A., Requena-Torres M.A., Garcia-Marin M., Kunneriath D., Zensus A., Britzen S., Sabha N., Shahzamanian B., Borkar A., Fischer S. <Astron. Astrophys. 603, A68 (2017)> =2017A&A...603A..68M (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Molecular clouds ; Millimetric/submm sources Keywords: Galaxy: center - Galaxy: nucleus - submillimeter: ISM - ISM: molecules - ISM: clouds - ISM: kinematics and dynamics Abstract: We report serendipitous detections of line emission with the Atacama Large Millimeter/submillimeter Array (ALMA) in bands 3, 6, and 7 in the central parsec down to within 1" around Sgr A* at an up to now highest resolution (<0.5") view of the Galactic center (GC) in the submillimeter (sub-mm) domain. From the 100GHz continuum and the H39α emission we obtain a uniform electron temperature around Te∼6000K for the minispiral. The spectral index (S∝να) of Sagittarius A* (Sgr A*) is ∼0.5 at 100-250GHz and ∼0.0 at 230-340GHz. The bright sources in the center show spectral indices around -0.1 implying Bremsstrahlung emission, while dust emission is emerging in the minispiral exterior. Apart from CS, which is most widespread in the center, H13CO+, HC3N, SiO, SO, C2H, CH3OH, 13CS and N2H+ are also detected. The bulk of the clumpy emission regions is at positive velocities and in a region confined by the minispiral northern arm (NA), bar, and the sources IRS 3 and 7. Although partly spatially overlapping with the radio recombination line (RRL) emission at same negative velocities, the relation to the minispiral remains unclear. A likely explanation is an infalling clump consisting of denser cloud cores embedded in diffuse gas. This central association (CA) of clouds shows three times higher CS/X (X: any other observed molecule) ratios than the circumnuclear disk (CND) suggesting a combination of higher excitation, by a temperature gradient and/or infrared (IR) pumping, and abundance enhancement due to UV and/or X-ray emission. Hence, we conclude that this CA is closer to the center than the CND. Moreover, we find molecular line emission at velocities up to 200km/s. Apart from the CA, we identified two intriguing regions in the CND. One region shows emission in all molecular species and higher energy levels tested in this and previous observations and contains a methanol class I maser. The other region shows similar behavior of the line ratios such as the CA. Outside the CND, we find the traditionally quiescent gas tracer N2H+ coinciding with the largest IR dark clouds (IRDC) in the field. Methanol emission is found at and around previously detected methanol class I masers in the same region. We propose to make these particular regions subject to further studies in the scope of hot core, cold core, and extreme photon and/or X-ray dominated region (PDR/XDR) chemistry and consequent star formation in the central few parsecs. Description: ALMA Cycle 0 data of band 3, 6, and 7 around the frequencies 100GHz, 250GHz, and 340GHz tuning (PI: Falcke) for a single pointing on Sgr A* (17h45m40.04s, -29d00m28.12s). XXXXXip: primary beam corrected image/cube XXXXXpb: primary beam image/cube (needed to restore uncorrected image for noise clipping) s0 - s3: spectral windows (spw) 0 - 3 (TDM setup) XXXsXXX: cube of an entire spw for natural weighting XXXcnXX: continuum for natural weighting XXXcuXX: continuum for uniform weighting File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 220 30 List of fits datacubes and images fits/* 0 30 Individual fits datacubes and images
See also: J/A+A/502/91 : Proper motions of stars near SgrA* (Schoedel+, 2009) J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010) J/A+A/534/A117 : NIR polarimetry of sources near SgrA* (Buchholz+, 2011) J/ApJ/755/90 : [NeII] emission line obs. from SgrA West (Irons+, 2012) J/MNRAS/428/2731 : SgrA* emission at 7mm (Beaklini+, 2013) J/A+A/582/A118 : OH-streamer in SgrA at 1665 and 1667MHz (Karlsson+, 2015) J/ApJ/820/90 : 4yr 1.3mm VLBI observations of SgrA* with EHT (Fish+, 2016) 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- 30 I3 --- Nz ? Number of slices 32- 57 A26 --- Obs.Date Observation date (YYYY-MM-DDThh:mm:ss.ssssss) 59- 69 E11.6 Hz Freq Observed frequency, or lower value of frequency interval for datacubes 71- 81 E11.6 Hz BFreq ? Upper value of observed frequency for datacubes 83- 92 E10.5 Hz dFreq ? Frequency resolution for datacubes 94- 99 I6 Kibyte size Size of FITS file 101-111 A11 --- FileName Name of FITS file, in subdirectory fits 113-220 A108 --- Title Title of the FITS file
Acknowledgements: Lydia Moser, moser(at)astro.uni-bonn.de This data is based on the following ALMA data: ADS/JAO.ALMA#2011.0.00887.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan) and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ.
(End) Lydia Moser [AIfA, Bonn, Germany], Patricia Vannier [CDS] 16-Mar-2017
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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