ILHUIYOLITZIN VILLICANA PEDRAZA
I studied an extragalactic spectra line survey at 1mm of the nearby galaxies NGC 253, NGC 4945 and Arp 220 using APEX.I found 150 transitions from 26 molecules for the starburst NGC 253, 136 transitions of 24 molecules for the Seyfert 2 NGC 4945, and 64 transitions of 17 molecules from the ULIRG Arp 220. I did a molecular comparison between the three sources of studio at 1mm with those published at 2mm and 3mm before. Column densities were obtained using Local Thermodinamical Equilibrium (LTE).
The comparison with other frequencies shows the detection of molecules at 1mm not detected in other frequencies such as N2H+, CN, H2O for NGC 253; For Arp 220, the molecules detected only at 1mm were HCN, CCH, HCO+, HNC, OCS and H3O+; I found NO+, SO2, and H3O+ for NGC 4945 that were not detected in other frequencies using single dish.
Using my experience in radioAstronomy and previous experience in optical band (Multifrequency Study of the Blazar 3C 454.3, Galaxies 2016), I am now a guide for my undergraduate students thesis or projects. I am teaching the properties of the spectra using spectra of real observations from diverse database such SDSS motivating the students to continue in science or support it.
• A blazar is a region at the center of a galaxy, it emits powerful jets of radiation in the direction of the Earth.
• A starburst galaxy is a Galaxy undergoing a rapid burst of star formation.
• A Seyfert galaxy is spiral galaxies with unusually bright, small cores that fluctuate in brightness. Contain broad emission lines of highly ionized atoms. At the core contain supermassive black holes with masses as high as a billion solar masses.
ULIRG: ultraluminous infrared galaxies
I present a submillimetric line survey of extragalactic sources carried out by APEX. The surveys cover the 0.8 mm atmospheric window from 270 to 370GHz toward NGC253, NGC4945, and Arp220. I found in NGC 253, 150 transitions of 26 molecules. For NGC 4945, 136 transitions of 24 molecules, and 64 transitions of 17 molecules for Arp 220. Column densities and rotation temperatures have been determinate using the Local Thermodinamical Equilibrium(LTE) line profile simulation and fitting in the MADCUBA IJ software. The differences found in ratios between the Galactic Center and the starburst galaxies NGC 4945 and NGC 253 suggest that the gas is less processed in the latter than in the Galactic Center. The high 18O/17O ratios in the galaxies NGC 4945 and NGC 253 suggest also material less processed in the nuclei of these galaxies than in the Galactic Center. This is consistent with the claim that 17O is a more representative primary product than 18O in stellar nucleosynthesis (Wilson and Rood 1994); Also, I did a Multitransitions study of H3O+ at 307GHz, 364GHz, 388GHz, and 396GHz. From our non-LTE analysis of H3O+ in NGC253 with RADEX software online, I found that the collisional excitation cannot explain the observed intensity of the ortho 396 GHz line. Excitation by radiation from the dust in the Far-IR can roughly explain the observations if the H2 densities are relatively low. From the derived H3O+ column densities we conclude that the chemistry of this molecule is dominated by ionization produce by the starburst in NGC253 (UV radiation from the O stars) and Arp 220 (cosmic rays from the supernovae) and likely from the AGN in NGC4549 (X-rays ); Finally, I report, for the first time, the tentative detection of the molecular ion HCNH+ (precursor of HCN and HNC) toward a galaxy, NGC4945, abundance explain the claimed enhancement of HCN abundance in the AGN, due to the enhancement of the ionization rate by X-rays. The abundance is much larger than the Galactic center of the Milky Way.
I am convinced that train and teach young students from all the fields (not only STEM students), but they can also be in love with Astronomy. In this way the will convert to STEM or will support the STEM projects in the future. I use some spectra from the SDSS (Sloan Digital Sky Survey) to practice and train the students for the introductory class.
In Figure 1, I presented the spectra of the Blazar 3C 454.3 that I published in 2016. In Figure 2, I presented the Spectra of the Seyfert galaxy NGC 1068 observed in the near-infrared band using the Gemini telescope. In Figure 3, I presented the Molecular identification that I got for the starburst galaxy NGC 253 from 270-320GHz.
For Figure 4, I show the Fits for some molecules of NGC 253. Finally, in Figure 5, I presented a Spectra of one galaxy observed with the Sloan Digital Sky Survey (SDSS).