Dr. Mariana Lazarova

Assistant Professor

Office: BHS 221   |    Phone: (308) 865-8145   |    Email: lazarovam2@unk.edu

Dr. Mariana Lazarova

About

I am an Assistant Professor of Physics at the Department of Physics and Astronomy. I completed my Ph.D. in Physics in 2012 at the University of California, Riverside, with dissertation focus on observational astronomy under the guidance of Prof. Gabriela Canalizo.

I am interested in the place of quasars in galaxy evolution, and their possible connection to ultra-luminous infrared galaxies and starburst galaxies. In my research I use Keck, Spitzer, and Hubble space telescope data to study the nature of a rare class of broad absorption line (BAL) quasars, the so-called LoBALs.

Lazarova's CV

Research

My research involves optical and infrared observations of a rare subclass of objects belonging to the extended family of galaxies known as Active Galactic Nuclei (AGN). I am interested in determining the role of AGN in galaxy evolution. The defining characteristic of an AGN is the presence of an actively accreting supermassive black hole at its center, containing millions of solar masses. As nearby material falls into the black hole in a swirling fashion, it forms an accretion disk which is responsible for the immense radiation that AGN emit at all wavelengths. The brightest AGN are the Quasi-Stellar Objects (QSOs, or often referred to as quasars), dubbed so for their point-like appearance on optical images as a result of the nuclear emission outshining the entire galaxy itself.

I study a very rare class of quasars, which exhibit the signature of extreme velocity winds. Low-ionization Broad Absorption Line quasars (LoBALs) have very broad blue-shifted absorption lines of Mg II λ2800, the widths which indicate gas outflows ranging from 2,000 km/s up to 0.2c. These extreme winds are observed in 1-3% of the optically-selected quasars. There are two models interpreting their rarity: (1) either all quasars pass through a short outflow phase lasting 1-3% of their life, or (2) all quasars have outflows that can be observed only in a small range of orientations (i.e., the winds cover 1-3% of the quasar). Observational evidence favors the evolutionary model because LoBALs at low redshifts exclusively reside in galaxies with high infrared luminosities, disturbed morphologies, and young stellar populations as a result of a recent galaxy merger.

Are LoBALs a short, evolutionary phase in the life of all quasars, or simply an orientation effect?

Are LoBALs a short, evolutionary phase in the life of all quasars, or simply an orientation effect?

LoBALs are the most promising candidate to be young QSOs, caught in the act of clearing up the reservoir of gas in the galaxy as a result of a major merger. In my thesis work I test whether LoBALs are a short transition phase in quasar evolution by conducting an unprecedented systematic multiwavelength study of a statistically significant volume-limited sample of 22 LoBALs within 0.5 < z < 0.6, comparing (i) their spectral energy distributions (SEDs), (ii) host galaxies morphologies, and (iii) stellar population ages to those of quasars without outflows.

To better understand the nature of LoBALs, I use some of the world’s best telescopes to study this large sample of LoBALs:

(1) Spitzer Space Telescope (instruments: MIPS + IRS) – to study the SEDs, IR luminosities, SFRs, Mid-IR spectral properties of LoBALs in comparison to a control sample of type-1 QSOs;

(2) Hubble Space Telescope (instruments: WFC3,IR+UVIS) – to study the morphologies, map star forming regions, and map older stellar populations;

(3) Keck Telescope (instruments: LRIS/ESI) – to determine the dominant stellar population ages.


Teaching

Current courses schedule:

Fall 2017:

  • PHYS 346 (01): Modern Physics
  • PHYS 346 (02): Modern Physics Lab
  • PHYS 100: Physical Science
  • PHYS 100L: Physical Science Laboratory

Past courses at UNK:

  • PHYS 810: Mathematical Methods for Science Teachers
  • PHYS 410: Mathematical Techniques in Physics I
  • PHYS 360: Astronomy Methods I (Computational Astrophysics)
  • PHYS 210: Astronomy
  • PHYS 205: General Physics I
  • PHYS 205L: General Physics I Lab
  • PHYS 206L: General Physics II Lab

Personal

Apart from astronomy, my other passions in life revolve around doing my best in raising two happy little kids (that’s always a work in progress), yoga and dancing for instant personal happiness boost (I have to steal that time because it never fits in the daily schedule), escaping into nature for a recharging hike (I blame that need on my grandfather who used to drag me up the mountain slopes in the crack of dawn when I was little), painting, and taking photos of anything that catches my eye (well, usually both of them).