Nikta Amiri

Nikta Amiri

Research Scientist

Location
Greater Denver Area
Industry
Research

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Nikta Amiri's Overview

Current
Past
Education
Connections

246 connections

Nikta Amiri's Summary

I am a postdoctoral fellow of Astrophysics at the University of Colorado at Boulder. I have significant experience in project management, data analysis, and strong focus on learning new concepts, collaboration, and growth:

My expertise include:

• Statistical analysis (large datasets), hypothesis testing, survival analysis, machine learning, and principal component analysis
• Data science
• Communication, troubleshooting technical problems
• Advanced visualization, and data exploitation
• Model and algorithm development
• Analysis of remote sensing data from satellites and ground based telescopes
• Radio frequency signal processing, synthetic aperture interferometry, polarimetry
• Strategic problem solving
• Presentation skills
• Project management, international collaboration
• Professional briefings, reports, and proposals

Nikta Amiri's Experience

Educational Institution; 5001-10,000 employees; Higher Education industry

August 2012Present (2 years 2 months) Boulder, CO

My research focuses on astrometric monitoring of maser emitting regions in the Andromeda galaxy (M31), to measure its transverse velocity and geometric distance.

My research experience include:

• Use advanced statistical analysis including survival analysis, and hypothesis testing, to insure the accuracy of measurements and uncertainty estimates.
• Perform signal processing of remote sensing data from radio telescopes and infrared satellites.
• Plan, coordinate, and operate on-site and off-site radio astronomical observations.
• Code an efficient data analysis pipeline to extract astronomical sources from large data sets (hundreds of GB and TB size).
• Utilize machine learning tools including principal component analysis, and regression on astronomical data.
• Develop algorithms in Python, Matlab, and R for analysis of data from Spitzer and Herschel satellites.
• Develop several innovative proposals as a primary investigator for astronomical observations.
• Collaborate with scientists in the United States and Europe in multi-institutions as the team leader
or member of an N-person team.
• Perform technical trouble shooting, test, and verification of astronomical observations.

Educational Institution; 5001-10,000 employees; Research industry

September 2007October 2011 (4 years 2 months) Leiden University, The Netherlands

• Developed a data mining algorithm to characterize sources detected from astronomical observa
tions.
• Developed software in Fortran to model an astrophysical system and compare the numerical results with astronomical observations.
• Successfully submitted several proposals as a primary investigator in collaboration with scientists in the United States and Europe.
• Led several on-site and off-site astronomical observations using various telescope facilities in the United States and Europe.
• Performed image processing and calibration of microwave remote sensing data from synthetic aperture interferometers including the US based Very Long Baselines Array, the European VLBI Network, and the Very Large Array.

Educational Institution; 10,001+ employees; Research industry

September 2006September 2007 (1 year 1 month) University of Manchester, UK

Nikta Amiri's Volunteer Experience & Causes

  • Volunteer Experience

    • Co-president of the postdoctoral association

      University of Colorado
      2013 present (1 year)

      Work under the vice chancellor of research to organize events/workshops and invite speakers from various disciplines for postdocs.

Nikta Amiri's Courses

  • MSc, Astronomy & Astrophysics

    The University of Manchester

    • Galactic Astronomy
    • Frontiers of Astrophysics
    • Radio Astronomy

Nikta Amiri's Languages

  • English

    (Full professional proficiency)
  • Persian

    (Native or bilingual proficiency)

Nikta Amiri's Honors and Awards

  • Marie Curie fellowship

    • September 2007

    European Framework 6 Marie Curie Early Stage Training fellowship

Nikta Amiri's Skills & Expertise

  1. Fortran
  2. Matlab
  3. Data Visualization
  4. Radio Frequency Engineering
  5. synthetic aperture interferometry
  6. communication
  7. Proposal Leadership
  8. Project Management
  9. international collaboration
  10. Remote Sensing
  11. Microwave Synthesis
  12. Troubleshooting
  13. Verification
  14. Statistical Data Analysis
  15. Principal Component Analysis
  16. Regression Analysis
  17. Survival Analysis
  18. systems engineering
  19. Large-scale Data Analysis
  20. Image Processing
  21. python
  22. IDL programming
  23. physics
  24. Linux
  25. Numerical Analysis
  26. Signal Processing
  27. Statistics
  28. Algorithms
  29. Astrophysics
  30. Machine Learning
  31. Scientific Computing
  32. Mathematica
  33. R
  34. IDL

View All (34) Skills View Fewer Skills

Nikta Amiri's Publications

  • VLBA SiO maser observations of the OH/IR star OH 44.8-2.3: magnetic field and morphology

    • Astronomy & Astrophysics
    • January 2012
    Authors: Nikta Amiri, Wouter Vlemmings, Athol Kemball, Huib Jan van Langevelde

    SiO maser emission occurs in the extended atmosphere of evolved stars and can be studied at high angular resolution. Very long baseline interferometry (VLBI) observations of Mira variables indicate that SiO masers are significantly linearly polarized with linear polarization fraction up to 100%. However, no information is available at high angular resolution for SiO masers in higher mass loss OH/IR stars. We extend the VLBI SiO maser studies to OH/IR stars. The observations enable us to understand the SiO pumping mechanisms in higher mass loss evolved objects and compare those with Mira variables. Additionally, polarimetric observations of SiO masers help us to understand the magnetic field strength and morphology and to distinguish between conflicting polarization theories. The 43 GHz SiO maser observations of the OH/IR star OH 44.8-2.3 were performed with the VLBA in full polarization spectral line mode. Auxiliary EVLA observations were performed to allow for the absolute calibration of the polarization angle. The Zeeman splitting was measured by cross correlating the right and left circular polarization spectra as well as the S-curve fitting. Additionally, we analyzed the 1612 MHz OH maser observations of OH 44.8-2.3 from the VLA archive. The SiO masers of OH 44.8-2.2 form a ring located at ~5.4 AU around the star. The masers appear to be highly linearly polarized with fractional linear polarization up to 100%. The linear polarization vectors are consistent with a dipole field morphology in this star. We report a tentative detection of circular polarization of ~0.7% for the brightest maser feature. The magnetic field measured for this feature corresponds to 1.5\pm0.3 G. Additionally, the distribution of the 1612 MHz OH maser emission could indicate an elongated morphology.

  • The kinematics and magnetic fields in water-fountain sources based on OH maser observations

    • Astronomy & Atrophysics Journal
    • 2011
    Authors: Nikta Amiri, Wouter Vlemmings, Huib Jan van Langevelde
  • The magnetic field of the evolved star W43A

    • Astronomy & Astrophysics Journal
    • January 2010
    Authors: Nikta Amiri, Wouter Vlemmings, Huib Jan van Langevelde
  • Magnetic Fields And Developing Asymmetries In Circumstellar Masers

    • http://adsabs.harvard.edu/abs/2011AAS...21821904A
    Authors: Nikta Amiri, Wouter Vlemmings, Huib Jan van Langevelde, Athol Kemball

    Maser emission occurs in different regions of the circumstellar envelopes (CSEs) of evolved stars and can be studied at high angular resolution using radio interferometers. These masers are useful probes of the dynamics and kinematics of the outflow from AGB stars. Moreover, masers can be important tracers of the magnetic field strength and morphology at various distances from the central stars. It is expected that the magnetic field plays an important role in transforming spherically symmetric asymptotic giant branch (AGB) stars into a-spherical planetary nebulae (PNe). Theoretical modeling indicated that magnetically collimated jets may be responsible for the formation of the a-spherical PNe. Water fountain sources are a class of post-AGB objects in which H2O masers indicate high velocity collimated jets. Our radio interferometric observations indicate that asymmetries are also present in the OH maser region of the envelope. We performed kinematical reconstruction in order to understand the distribution of OH masers in the CSEs of these stars. Our results show that the OH masers could have either equatorial or bi-conical distribution. Additionally, the observations reveal significant field strength for the OH maser region of these objects, which show the possible role of the magnetic field in collimating the CSEs.
    At distances close to the central stars, between the photosphere and the dust formation zone, SiO masers occur. SiO maser polarimetry has been performed for Mira variables and supergiants and seems to indicate dynamically significant and ordered magnetic fields. We extended these studies and performed VLBA SiO maser polarization observations of objects with more extreme mass-loss, in order to understand the origin of the transition between the AGB and PNe. These observations will enable us to understand the SiO emission mechanisms and possibly distinguish between competing models on the origin of the SiO maser polarization.

  • W43A: magnetic field and morphology

    • Asymmetric Planetary Nebulae 5 conference, held in Bowness-on-Windermere, U.K., 20 - 25 June 2010, A. A. Zijlstra, F. Lykou, I. McDonald, and E. Lagadec, eds. (2011) Jodrell Bank Centre for Astrophysics
    Authors: Nikta Amiri, Wouter Vlemmings, Huib Jan van Langevelde

    Water fountain sources are a class of post-AGB stars that exhibit highly collimated H_2O maser jets. These jets are likely associated with the origin of asymmetric PNe. Magnetic fields are found to play an important role in collimating these jets. We measured the Zeeman splitting of the 1612 MHz OH masers in W43A, which is an archetype of this class of objects. A magnetic field of 100μG was derived for the OH maser region of this source. Additionally, we performed kinematical re-construction of the OH maser region of this source. Our results show that the OH masers are most likely distributed in the equatorial region of the circumstellar envelope . The equatorial enhancement of the OH masers could be due to the presence of a binary companion.

Nikta Amiri's Education

Universiteit Leiden

PhD, Astrophysics

20072011

Thesis: "Developing Asymmetries in AGB stars: Occurrence, Morphology, and Polarization of Circumstellar Masers"
Promotor: Prof. Ewine van Dishoeck
Supervisors: Dr. Huib Jan van Langevelde, Dr. Wouter Vlemmings (Onsala Space Observatory)

The University of Manchester

MSc, Astronomy & Astrophysics

20062007

Thesis: ”Anomalous Emission from Dust in HII Regions”
Supervisors: Prof. Rod Davies, Prof. Peter Wilkinson

Amirkabir University of Technology - Tehran Polytechnic

BSc, Mechanical Engineering

20012005

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