Sciences and Exploration Directorate

Sangeeta Malhotra


Sangeeta Malhotra's Contact Card & Information.
Phone: 301.286.6955
Org Code: 665
Mail Code 665
Greenbelt, MD 20771

Current Projects

Lyman alpha Galaxies at the Epoch of Reionzation (LAGER)


This is a multinational collaboration to survey 20+ square degrees in narrow band filters to finc lyman-alpha galaxies at redshift of 7. The aim of this project is to determine the neutral fraction of inter-galactic medium at the epoch of reionization.

Green Peas as local analogs of Lyman-alpha galaxies

Green Pea galaxies are nearby galaxies with extremely strong emission lines in their optical spectra. They were named by citizen scientist volunteers in the Galaxy Zoo project, because they appear small, round, and green in color-composite Sloan Digital Sky Survey images. Their unusual color is because the optical emission lines are strong enough to dominate over starlight in their colors.

 Our research has shown that green peas are good nearby analogs of high redshift Lyman alpha galaxies. Their relative proximity allows detailed study of many properties that cannot be studied well at the distances of high-redshift Lyman alpha Green Pea galaxies are nearby galaxies with extremely strong emission lines in their optical spectra.  These include detailed studies of Lyman alpha line profiles, chemical abundances, and gas content.

Cosmic Dawn studies with WFIRST

WFIRST has the potential to make groundbreaking contributions in the study of Cosmic Dawn. We are making detailed investigations and simulations of WFIRST observations to find high redshift gaklaxies and quasars in the first billion light years of the universe. This is in collaboration with an international team.


Research Astrophysicist

GSFC - GreenBelt, MD

2017 - Present


School of Earth and Space Exploration Arizona State University - Tempe, AZ

January 2006 - December 2016


Space Telescope Science Institute - Baltimore, MD

2001 - 2006

Hubble Fellow

Johns Hopkins University National Optical Astronomy Observatory - Baltimore, MD Tucson, AZ

1998 - 2001

NRC fellow

IPAC, Caltech. JPL - Pasadena, CA

1995 - 1998


1995 PhD is Astrophysical Sciences, Princeton University

1990 MSc in Physics, Indian Institute of Technology, Kanpur.

1988 BSc (Honors) Physics, Delhi University.

Professional Societies

American Astronomical Society

1993 - Present

International Astronomical Union

1993 - Present

Teaching Experience

Dr Malhotra was a professor at Arizona State University between 2006 and 2017.  She has mentored students and postdocs at all levels.



2011. "Spectroscopic Study of the HST/ACS PEARS Emission-line Galaxies." Astronomical Journal 141 (64): [Full Text] [Journal Article/Letter]

2011. "HST WFC3 Early Release Science: Emission–Line Galaxies from Infrared Grism Observations." Astronomical Journal 141 (14): [Full Text] [Journal Article/Letter]

2009. "Spectroscopic Confirmation of Faint Lyman Break Galaxies Near Redshift Five in The Hubble Ultra Deep Field." The Astrophysical Journal 697 (1): 942-949 [10.1088/0004-637x/697/1/942] [Journal Article/Letter]

2009. "Emission-Line Galaxies from the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) Grism Survey. I. The South Fields." The Astronomical Journal 138 (4): 1022-1031 [Full Text] [10.1088/0004-6256/138/4/1022] [Journal Article/Letter]

2008. "Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results." The Astronomical Journal 135 (4): 1624-1635 [10.1088/0004-6256/135/4/1624] [Journal Article/Letter]

2005. "A Redshift z ~ 54 Lyα Emitting Galaxy with Linear Morphology in the GRAPES/Hubble Ultra Deep Field." The Astrophysical Journal 621 582 [Full Text] [10.1086/427622] [Journal Article/Letter]

2004. "GRAPES, Grism Spectroscopy of the Hubble Ultra Deep Field: Description and Data Reduction." The Astrophysical Journal Supplement Series 154 501 [Full Text] [10.1086/422582] [Journal Article/Letter]


2018. "The WFIRST Exoplanet Microlensing Survey." arXiv e-prints arXiv:1803.08564 [Report]

2009. "THEIA: Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy." American Astronomical Society, AAS Meeting #213, #45804; Bulletin of the American Astronomical Society, Vol 41, p362 213 362 [Full Text] [Proceedings]