X-ray Deep: Studying the Universe in X-rays



emma kleiner Emma Kleiner

alexandria clark Alexandria Clark, Texas Tech.


paras pokharel

Paras Pokharel is an undergraduate student at Howard University. As a NASA intern during the summer of 2019, Paras worked with Dr. Andy Ptak.


Violet Replicon

Following her summer internship in 2017, Violet Replicon returned in 2018 to continue working with Dr. Ann Hornschemeier, Dr. Antara Basu-Zych, and Dr Andrew Ptak.


Margaret Lazzarini
Margaret Lazzarini is a graduate student at the University of Washington in the Astronomy Department working with Dr. Benjamin Williams. She received her B.S. in Astronomy & Physics from Yale University and worked for two years before graduate school as a high school physics and astronomy teacher in Los Angeles. As a NASA intern, Margaret is working with Dr. Ann Hornschemeier studying the pulsar population in M31 using NUSTAR, Chandra, and Hubble observations.

Violet Replicon

Violet Replicon is a student at University of New Mexico in the Physics and Astronomy department. She is currently working on getting her Bachelor’s in Astrophysics. Violet is working with Dr. Ann Hornschemeier, Dr. Antara Basu-Zych, and Dr Andrew Ptak to derive the x-ray luminosities of tens of thousands of galaxies from their stellar mass and star formation rate. From this she is planning on simulating the eROSITA telescope to see if this instrument can detect the galaxies.

Chris Murphy

Chris Murphy is an undergraduate student at the University of the Virgin Islands studying Physics with a concentration in Astronomy. As an intern at GSFC, Chris is using HST data to examine UV, Optical, and IR properties of stars within NGC 253.


Mackenzie Jones Mackenzie Jones is a PhD Candidate at Dartmouth College in the department of Physics and Astronomy. She received her Bachelor’s degree in Physics from Butler University with a concentration in Astronomy. As a NASA Harriett G. Jenkins Fellow, she is working with Dr. Ann Hornshemeier, Dr. Andy Ptak and the GSFC X-ray group to model the X-ray spectra of the full AGN population using NuSTAR.

Charlotte Olsen Charlotte Olsen is an undergraduate at Humboldt State University majoring in Physics with an Astrophysics emphasis. As an intern at GSFC Charlotte works with Dr. Antara Basu-Zych on studying star formation triggered by galaxy interactions through the analysis of UV data from the Swift UVOT space telescope. Charlotte will be presenting her study of tidally triggered star formation in NGC 5851 at the January AAS meeting, and hopes that her work can provide the foundation of a multi wavelength population study of star formation in close galaxy pairs and groups.

David EspinozaDavid Espinoza is a grad student at Catholic University of America. From Honduras, he finished his physics bachelor degree at National University of Honduras to move later to Spain for a master degree in physics and mathematics at University of Granada. As an intern in GSFC he works in Dr. Hornschemeier group, assisting on the analysis of Chandra and NuStar data of galaxies, which includes spatial and spectral analysis of X-ray binaries, AGN and diffuse components.


Dave Coulter Dave Coulter is an undergraduate at Portland State University, majoring in Physics. As an intern at GSFC, he worked with Drs. Lehmer, Hornschemeier, and Basu-Zych on testing initial mass function variations by studying the low mass X-ray binary populations within low-mass elliptical galaxies. He will be presenting these results at the January 2016 American Astronomical Society meeting in Kissimmee, FL.

Violet Replicon Violet Replicon is an undergraduate at New Mexico Institute of Mining and Technology in Socorro, New Mexico. She is majoring in physics with a concentration in astrophysics. While at GSFC, Violet worked under Dr. Ann Hornschemeier and Dr. Andy Ptak classifying X-ray binaries using MAXI (Monitor of All-sky X-ray Image) and NuSTAR (Nuclear Spectroscopic Telescope Array) data.


Joshua Tyler Joshua Tyler started a PhD course at The Catholic University of America in fall 2014, concentrating in Astronomy and Astrophysics. He received his Bachelor's degree in physics, with a concentration in astrophysics, at Towson University. As an intern at NASA GSFC, he worked with Dr. Bret Lehmer and Dr. Ann Hornschemeier characterizing bright X-ray sources in starburst galaxies using data from simultaneous observations with the Chandra X-ray Observatory and NuSTAR.


Doug Heeter Doug Heeter is a high school Physics and Astronomy teacher at North Harford High School and conducted research at NASA GSFC as part of the BEST Program through Towson University. The BEST program is designed for teachers to bring authentic research experiences back into the classroom for students, in order to promote STEM (Science, Technology, Engineering, and Mathematics) mindsets and careers. He has a B.S. degree in Secondary Education, Earth and Space Science from Slippery Rock University of Pennsylvania and a Master of Science in HRD: Education Leadership from Towson University. As an intern, he worked with Dr. Andy Ptak and Dr. Ann Hornschemeier examining POGS (PS1 Optical Galaxy Survey) observation data and Chandra X-ray field observations looking for significant x-ray emission within the optical extent of the galaxy beyond any potential from the galactic center.

Greg Hrinda Greg Hrinda is a high school Physics teacher at Pikesville High School and conducted research at NASA as part of the BEST Program through Towson University. The BEST program is designed for teachers to bring authentic research experiences back into the classroom for students, in order to promote STEM (Science, Technology, Engineering, and Mathematics) mindsets and careers. He has a Bachelor degree in Physics from RIT and a Master of Arts in Science Education from the Univeristy of Pittsburgh. As an intern, he worked with Ann Hornschemeier on robust measurements of star formation rates and stellar masses of members in the in-fall region of the Coma Cluster. These regions will be compared to the local X-ray emissions to identify quenching and environmental effects of the cluster.

Matthew Berkeley Matthew Berkeley is a Master of Space Studies student at the International Space University in France and conducted a research internship with the group as part of the NASA/ISU Internship Program. His Bachelor degree is in Astrophysics from Trinity College Dublin. As an intern, he worked with both Ann Hornschemeier on X-ray stacking of galaxies in the Chandra Deep Field South and Bret Lehmer on optical source extraction in local galaxies, imaged by Hubble, to find optical counterparts to luminous X-ray sources. He also updated the group webpage.

Johanna-Laina Fischer Johanna-Laina Fischer (January - August 2013) is now a graduate student at the University of Pennsylvania concentrating on Cosmology. Before interning at NASA GSFC, she graduated from the Florida Institute of Technology where she received her B.S. degrees in Physics and Astronomy/Astrophysics. While interning at NASA GSFC, she worked with Dr. Bret Lehmer and Dr. Ann Hornschemeier studying the properties of luminous X-ray binaries in nearby and distant galaxies using data from the Chandra X-ray Observatory.


Derek Hammer Derek Hammer was a graduate student in the Department of Physics and Astronomy of the Johns Hopkins University (he received his PhD in 2012 and currently works at STSCI with the Hubble Space Telescope team). His research is in the area of observational extragalactic astronomy, particularly as it applies to normal galaxies observed at ultraviolet (UV), optical, and infrared wavelengths. His work focuses on the UV properties of dwarf galaxies in clusters (e.g. luminosity function, star formation history) in an effort to link the effects of the dense cluster environment on dwarf galaxy evolution. To achieve this goal, he works with imaging data from several observatories including GALEX, XMM-Optical Monitor, SDSS, HST-ACS, and Spitzer, in addition to ground-based optical spectra.

Adrian Lucy Adrian Lucy was a senior undergraduate and Goldwater Scholar at the University of Oklahoma. With Karen Leighly, he worked in the UV/optical/IR on constraining the geometry and energetics of broad absorption line quasar outflows. He also worked with Al Wootten and Nuria Marcelino at the NRAO in Charlottesville, using ALMA data to determine the origin of ammonia deuteration in Orion KL. At Goddard, Adrian worked with Bret Lehmer on Chandra data of a z=2.23 galaxy protocluster, moving towards an understanding of local massive ellipticals' evolutionary history. Currently, Adrian is a PhD student at Columbia University.


Kumiko Morihana Kumiko Morihana received her doctoral degree at the University of Tokyo in 2012. As an intern at Goddard Space Flight Center, she studied the growth of supermassive black holes, the most massive structures in the universe, using X-ray (Chandra) and optical (HST) data with Bret Lehmer. Now she works at Nishiharima Astronomical Observatory at the University of Hyogo in Japan. She mainly works with populations constituting the Galactic Ridge X-ray Emission using X-ray and NIR data.

Gladys Kober Gladys Kober received her B.S. in Astronomy from UFRJ (Federal University of Rio de Janeiro, Brazil) and completed her masters degree in Extragalactic Astrophysics at National Observatory in Brazil. She worked for 2 years in a planetarium in Rio doing public outreach. For the last 10 years she has been working at GSFC as a data analyst in astronomy. She acquired experience in data analysis from the interstellar medium and circumstellar medium around Eta Carina, one of the most massive stars in our galaxy. More recently she joined Dr. Hornschemeier's group working with photometry of Compact Groups of Galaxies.


Olivia Smarr Olivia Smarr (summer 2009) was a senior at Elizabeth Seton High School in Bladensburg, Maryland. In the summer of 2009 she completed her second internship at NASA Goddard as an intern in the High School Intern Program, working with Dr. Ann Hornschemeier conducting simulations for the Nuclear Spectroscopic Telescope Array (NuSTAR). In her previous internship she studied protostellar jets and disks under the mentorship of Drs. Jennifer Wiseman and Carol Grady.

Svetlana Shkolyar Svetlana Shkolyar's (summer 2009) research interest is to contribute to our knowledge of the universe in which we live through astronomy. This interest has led her to be an M.S. track UND Space Studies student pursuing a solar physics thesis. She graduated Cum Laude with a Physics B.S. from the University of North Florida. There, she was a Research Assistant in the UNF PICM Sensor Lab where she received an Undergraduate Student Research Project grant from the NASA Florida Space Grant Consortium for this effort. She then attended the University of Florida where she received a master’s degree in Mass Communication, Science Journalism Track. She spent the summer of 2009 doing an education/outreach internship with Goddard SFC's NASA Academy.

Ashley Campbell Ashley Campbell (summer 2009) received her B.S. in Physics and Mathematics from the University of Alabama in Huntsville in 2009. She is currently a physics graduate student at the University of Alabama in Hunstville. During the summer of 2009, she worked with Dr. Ann Hornschemeier on NuStar simulations of galaxies as part of the Student Internship Program. Her interests include formation and evolution of galaxies, Dark Matter, and AGN.

John Sheets John Sheets (September 2006, Summers 2007, 2008, 2009) was a current undergraduate student at the University of Washington, Seattle campus where he majors in Astronomy and Physics. He has been a part of Dr. Hornschemeier's group since September 2006 when first started work as a high school intern. He has been involved with the UV Luminous Galaxy X-ray emission project, as well as obtaining astrometric solutions for optical observations of Hickson Compact Groups of galaxies.


Kalman Knizhnik Kalman Knizhnik was a physics and astronomy student at the University of Maryland, College Park. He started working with Dr. Ann Hornschemeier in the summer of 2008 as part of the Science and Engineering Student Internship. Now part of the CRESST program, he is researching the X-ray properties of Hickson Compact Groups, focusing specifically on the X-ray dim groups. Prior to starting this work, Kalman spent the previous summer at NASA GSFC's Heliophysics Division, creating a three dimensional model of magnetic clouds. Before that, as part of NASA GSFC's Space Physics Data Facility, he helped work on a three dimensional model of the Earth's bow shock.


Erin Zekis Erin Zekis (August 2006-December 2006) was a graduate student at the University of Colorado at Boulder. She got her B.S. in Physics from Rose-Hulman Institute of Technology in 2008. In 2006 she began work with Dr. Ann Hornschemeier on a spectroscopic and photometric study of the color-magnitude diagram of the Coma cluster.

Kalin Kanov Kalin Kanov (summer 2006) was a Ph.D. student in the Department of Computer Science at the Johns Hopkins University, where he has been since September 2008. In 2006 Kalin graduated with distinction from the University of Virginia with a B.A. in Astronomy and Physics. At the University of Virginia he completed a senior thesis, entitled "Chandra Observations of the Interaction of the Radio Source and Cooling Core in Abell 2063". From June 2006 until August 2006 Kalin participated in the Student Internship Program at NASA Goddard Space Flight Center, where he worked on a project entitled "Studying Galaxies in Their Most Common Environment: A multiwavelength survey in Coma." under the mentorship of Dr. Ann Hornschemeier. Kalin studied 13 of the Hickson Compact Groups (HCGs), and conducted a multiwavelength survey of the galaxies in those groups, which included observations with the Chandra X-ray Observatory, GALEX, Sloan Digital Sky Survey (SDSS), 2 Micron All Sky Survey (2MASS), XMM − Newton, Spitzer, Swift and optical R-band images from the 60 inch telescope at Palomar Mountain.