Structure and Kinematics of a Jet - Accretion disk system

Undergraduate Thesis

Project description: For my undergraduate thesis, I worked with G.N. Ortiz-Leon to study the behavior of water masers around two YSO (Young Stellar Objects): CARMA 6 & CARMA 7. Using observations with the Very Long Baseline Array we can reach angular resolutions in the order of fractions of milliarcseconds, which is great to resolve these masers.

For this project I used the following tools:

• Common Astronomy Software Applications (CASA): Software for radio astronomy
• Astronomy Image Processing System (AIPS): Used for data calibration
• Python (for almost all data analysis)

The water maser emission has a wavelength of 22.2GHz, but as we can get data from different wavelengths, if we detect the emission in a different channel, then using the Doppler effect we can assume that that certain emission has a different velocity (getting closer or further), and with that we can try to study (using the Disk Wind model) from which distance of the star does that emission got ejected from the disk.

Detections of water masers on different velocity channels (rest velocity is 12.5km/s). Figure from CARMA 6 on epoch D.

All detections and its respective velocities, from here we can study the model and get an angular velocity, from which and assuming the conservation of angular momentum, we get the distance from the star from which these masers got ejected.

The integrated flux density from the observations, we can see that the brightness of the masers gets lower and lower as time passes.

The paper can be read at:
Article (English version)
Article (Spanish version)