ALMA¶
The Atacama Large Millimeter/submillimeter Array (ALMA) is a radio interferometer constructed in the Atacama Desert at 5,000 meters above sea level in the northern Republic of Chile in South America. This radio telescope is composed of 66 high-precision antennas, which operate on wavelengths of 0.32 to 3.6 mm. Its main array has fifty antennas, each with 12-meter diameters, which act together as a single telescope: an interferometer. This is complemented by a compact array of four antennas with 12-meter diameters and 12 antennas with 7-meter diameters. ALMA’s antennas can be configured in different ways, spacing them at distances from 150 meters to 16 kilometers, giving ALMA a powerful “zoom” variable, which results in images clearer than the images from the Hubble Space Telescope (ALMA basics).
ALMA main links¶
ALMA literature¶
- To be completed
Data analysis¶
This is a brief documentation to analyze synthetic ALMA data from Bifrost simulations that have been stored in .h5 files. To that end, it is necessary to clone the Bifrost code and DNS package for the following instructions.
Synthetic data from Bifrost¶
- To get a list of the existing synthetic ALMA data files (int.h5) within a folder, type:
f=alma_synthfiles() - The synthetic files contain the following variables:
For instance, to read Stokes_I, type:
list=['Stokes_I','Tau1','Wavelength']The units of the output variables are changed in the DNS routines.stokes_i=alma_readsynth(f(0),Stokes_I)This is the list of wavelengths and their correspondence with the different ALMA bands:; Stokes_I : Stokes Intensity in erg/cm^2 ; We convert it to temperature: ; Stokes_I * lambda^2/Kb ; Tau1 : Optical depth in cm ; We convert it to Mm ; Wavelength : Wavelength in Angstrom ; We convert it to mm0 : (lambda): 5000.000 for debugging purposes (should looks like a photosphere) Band 3 // 3.2 -> 2.77 [mm] 1 : (lambda): 32586136.73913, (freq) 92000000000.00121, (to K) 3.845497e+14 2 : (lambda): 31892814.68085, (freq) 94000000000.00017, (to K) 3.683600e+14 3 : (lambda): 31228381.04167, (freq) 95999999999.99896, (to K) 3.531715e+14 4 : (lambda): 28826197.88462, (freq) 104000000000.00137, (to K) 3.009272e+14 5 : (lambda): 28282307.35849, (freq) 105999999999.99835, (to K) 2.896786e+14 6 : (lambda): 27758560.92593, (freq) 107999999999.99969, (to K) 2.790491e+14 Band 6 // 1.30 -> 1.20 [mm] 7 : (lambda): 13091373.71179, (freq) 229000000000.00690, (to K) 6.206649e+13 8 : (lambda): 12978028.48485, (freq) 231000000000.00870, (to K) 6.099639e+13 9 : (lambda): 12866629.09871, (freq) 233000000000.00815, (to K) 5.995374e+13 10 : (lambda): 12236426.85714, (freq) 244999999999.99716, (to K) 5.422455e+13 11 : (lambda): 12137346.47773, (freq) 246999999999.99585, (to K) 5.334998e+13 12 : (lambda): 12039857.75100, (freq) 249000000000.00040, (to K) 5.249639e+13 Band 7 // 0.88 -> 0.84 [mm] 13 : (lambda): 8853882.39811, (freq) 338599999999.99500, (to K) 2.838927e+13 14 : (lambda): 8801892.48385, (freq) 340600000000.00104, (to K) 2.805685e+13 15 : (lambda): 8750509.57385, (freq) 342600000000.00214, (to K) 2.773023e+13 16 : (lambda): 8550840.21677, (freq) 350600000000.01038, (to K) 2.647917e+13 17 : (lambda): 8502338.57062, (freq) 352600000000.01105, (to K) 2.617963e+13 18 : (lambda): 8454384.03835, (freq) 354600000000.00323, (to K) 2.588515e+13
Model data from Bifrost¶
- To get a list of the existing model files (model.h5) that generated the ALMA synthetic files within a folder, type:
g=alma_modelfiles() - The model files contain the following variables:
The units of the output variables are as follows:
list=['Pgas','temperature','dens','dx','dy','z'];Pgas : Gas pressure in CGS ;temperature : Temperature in K ;dens : Total density in CGS ;dx : X axis in cm. Converted to Mm. ;dy : Y axis in Mm. Converted to Mm. ;z : Z azis in Mm. Converted to Mm.