Hooshang Nayyeri



Position: Graduate Student of Extragalactic Observational Astronomy

Advisor: Prof. Bahram Mobasher

Email: Hooshang dot Nayyeri at email dot ucr dot edu

Office: UC Riverside, Pierce Hall 2206




Main Research Interests:

I am mainly interested in galaxy formation and evolution.



Projects I am involved in:


  • Massive and Passive galaxies at z>3

I study the nature of massive and old galaxies through signatures in their Spectral Energy Distribution (SED). One of the most pronounce features in old galaxies SED is their Balmer/4000 A break. I have constructed color-color diagrams to identify these galaxies through Balmer Break selection and have compared their physical  as well as environmental properties to high-redshift star-forming galaxies the so-called Lyman Break galaxies.
Learn more about this ( Nayyeri et al. submitted)


  • GOODS + COSMOS High Redshift DEIMOS Spectroscopic Survey



I have been mainly observing three different fields in the sky  (COSMOS, GOODS-S and GOODS-N) since 2011  using DEIMOS instrument on KECKII. I have reduced, analaysed and cataloged these spectra  as well as spectra from previous years and compiled a huge spectroscopic sample containing thousands of spectra. I work mainly with the higher redshift sources ( LBGs, LAEs and BBGs) and compare their spectral properties.

  • Comparison of High redshift galaxy selection methods

I study different selection techniques used to identify the star-forming and passive galaxies at high redshift. One of the questions that I am seeking to answer is the difference between the BBG selection and old and massive candidates selected from other methods (such as the BzK; Daddi et al). Equally interesting is the comparison of the different populations of star-forming galaxies identified by the dropout Lyman Break technique and the narrow band selections of Lyman Alpha Emitters.  I plan to compare the physical and simulated properties of galaxies recovered from each of these selection criteria. Using empirical or model SEDs of galaxies and will generate a mock catalog of galaxies including photometry, redshift and other physical properties. Using this mock catalog along with the real identified candidates for each selection technique I would be able to quantify the distinctions and the overlaps in different selections and estimate the physical properties of the member candidates.
  • CANDELS Multi-Wavelength Cataloging

I am an active member of CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) multi-wavelength working group. We perform photometry of the sources observed with HST using the Template FITting (TFIT) algorithm. The TFIT uses prior information on the position and surface brightness of the sources from the highest resolution image (HST/ACS or WFC3) to measure the photometry in the low resolution image. This method is most useful in deriving the photometry of the low resolution blended sources, as these will be well separated in the high resolution image. I lead the work on COSMOS field but I am involved in other fields as well.
  • The Hubble Archival Program!

 The aim of this project is to measure self-consistent photometry, star formation rate, stellar mass and rest-frame colors for galaxies in all fields with  Hubble Space Telescope  observations (PI: Mobasher). We build consistent photometric catalogs (in terms of source identification and photometry) for all the fields. For this we use a modified version of the SExtractor software to select the sources in the highest resolution ACS bands by generating stacked ACS images (when available) to consistently detect sources in the blue and red bands. The conclusion of this work would allow for science unbiased by source selection, photometry and property measurement etc. So far we have completed the photometric catalog on the GOODS-S eld and we are now measuring the physical properties by fitting their SED.


  • Resolved (kpc-scale) study of Disk galaxies at Intermediate Redshifts.(read more)

My Resume:
You can find my CV here.

Other Interests: 


Traveling, Hiking and Photography!