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

Research Scientists

Dr. Ann Hornschemeier

ann.hornschemeier AT nasa DOT gov

Dr. Ann Hornschemeier Dr. Ann E. Hornschemeier specializes in studies of X-ray emission from X-ray binary populations, both in the local universe and at cosmologically interesting distances (z > 0.1). This work is carried out using surveys by space-based X-ray, UV, and infrared observatories as well as ground-based telescopes. She chairs the NuSTAR Starburst and Local Group science working group, carrying out observations on seven nearby galaxies, involving coordinated observations with Chandra, XMM-Newton and Swift, and a team of approximately ten scientists both at NASA GSFC and universities. Dr. Hornschemeier is also the Chief Scientist for the Physics of the Cosmos (PCOS) program, which is the high energy astrophysics and cosmology program at NASA and is also heavily involved in future missions as a research scientist at NASA, including co-chairing a science panel for the ESA Athena mission due for launch in 2028. Dr. Hornschemeier's CV is available HERE.

Dr. Andy Ptak

andrew.ptak AT nasa DOT gov

Dr. Andy Ptak Dr. Andy Ptak got his PhD in Physics from the University of Maryland, College Park in 1997, working at NASA/GSFC with Pete Serlemitsos and Rich Mushotzky on X-ray observations of starburst galaxies and low-luminosity active galactic nuclei. His current interests are in the X-ray properties of starburst galaxies, particularly hot gas and ultra-luminous X-ray sources (ULXs), and in active galactic nuclei. He also has a strong interest in astrophysics software development, having written an automated analysis program for Chandra and XMM-Newton data that produced one of the first serendipitous source catalogs for Chandra and XMM-Newton (www.xassist.org). He is a member of the LSST galaxy and astrostatistics science teams. He is currently the NuSTAR mission scientist, HST deputy project scientist for operations, and NASA Athena deputy study scientist. Prior to coming to GSFC he worked as a post-doc under Prof. Richard Griffiths at Carnegie-Mellon University (1997-2001) and as a research scientist at the Johns Hopkins University (2001-2010).

Dr. Antara Basu-Zych

antara.r.basu-zych AT nasa DOT gov
Web page: http://astroantara.wordpress.com/

Dr. Antara Basu-Zych Dr. Antara Basu-Zych (CV), received her Ph.D. in astronomy from Columbia University in Jan. 2009, having worked with Dr. David Schiminovich on Lyman break analogs (LBAs). These low-redshift (z < 0.3) analogs of distant Lyman break galaxies offer a more-detailed view into galaxy evolution in the early Universe. She began working at Goddard Space Flight Center (GSFC) as a NASA Postdoctoral Program (NPP) fellow, and has since continued at GSFC as a research scientist under the CRESST/UMBC program, with Dr. Ann Hornschemeier. Her current research interests are on studying the X-ray emission from starburst and low metallicity galaxies, especially for understanding how the X-ray emission of galaxies evolves over cosmic time and its role on heating the intergalactic medium (IGM). In addition, Antara is interested in studying galaxy evolution and star formation using multi-wavelength datasets, observing actively star-forming galaxies to study their stellar (and X-ray binary) populations and addressing the question(s): what triggers (and quenches) star formation activity in galaxies? Separate from these research topics, Dr. Basu-Zych serves as a HEASARC staff scientist, ingesting tables, maintaining the HEASARC archives and webpages, and monitoring usage statistics.

Dr. Kristen Garofali

kristen.garofali AT nasa DOT gov

Dr. Kristen Garofali

Dr. Kristen Garofali completed her Ph.D. in astronomy at the University of Washington with Prof. Benjamin Williams in 2018 before moving to the University of Arkansas, where she was a postdoctoral fellow from 2018-2020 working with Prof. Bret Lehmer. She is currently a NASA Postdoctoral Program fellow at NASA/GSFC. Kristen studies how the X-ray emission from nearby star-forming galaxies, consisting primarily of emission from X-ray binaries and the hot interstellar medium, is affected by the host galaxy’s recent star formation history and gas-phase metallicity.

Dr. Edmund Hodges-Kluck

edmund.hodges-kluck AT nasa DOT gov

Dr. Edmund-Hodges Kluck Dr. Edmund Hodges-Kluck received his Ph.D. at the University of Maryland with Christopher Reynolds, and was a postdoctoral scholar at the University of Michigan working with Joel Bregman and Elena Gallo. He studies the flows of gas in and around galaxies in most wavelengths but specializes in X-rays, with specific interests in AGN- and supernovae-driven outflows, as well as measuring the properties of circumgalactic gas and dust. He is a member of the NASA/JAXA XRISM (X-Ray Imaging and Spectroscopy Mission) science team, supports the ESA/NASA Athena mission, and works on ideas for future missions.

Dr. Ryan Tanner

ryan.tanner AT nasa DOT gov

Dr. Ryan Tanner Dr. Ryan Tanner specializes in simulations of galactic outflows and synthesizing observations of outflows based on his models. He received his PhD from the University of North Carolina at Chapel Hill where he worked with Drs. Fabian Heitsch and Gerald Cecil. As a grad student he gained experience running large scale simulations on supercomputers at UNC. After graduating he spent time teaching astronomy and physics at Augusta University, but decided to return to research as a NASA postdoc working with Dr. Kim Weaver. Currently he does research on both starburst and AGN driven outflows, including combined starburst-AGN outflows. His work focuses on finding ways to disambiguate AGN contributions to outflows vs. starburst contributions. He also studies how star formation efficiencies determine the composition and extent of galactic outflows.

Dr. Panayiotis Tzanavaris

panayiotis.tzanavaris-1 AT nasa DOT gov

Dr. Panayiotis Tzanavaris Dr. Panayiotis Tzanavaris has studied the intergalactic medium with quasar absorption lines, astrophysical constraints on the variation of fundamental constants, and the X-ray luminosity function of normal galaxies. He has extensive expertise in techniques and analysis from different wavelength regions, including radio, optical, UV and X-ray. He is interested in multiwavelength (UV, optical, X-ray, IR) AGN and star formation properties of Hickson Compact Groups of galaxies. He has performed high-performance computing simulations of populations synthesis models for X-ray binary populations in normal galaxies. He is exploring X-ray reprocessing in nearby AGNs with broadband X-ray data to decipher the relative importance of narrow vs. broad Fe Kα emission, including associated reflection spectra. He further provides support to the US Athena NASA Study Team and NASA's Physics of the Cosmos Program. He holds an M. Sci. from the University of London, King's College, and a Ph.D. from the University of Cambridge, Institute of Astronomy/Churchill College.

Dr. Mihoko Yukita

mihoko.yukita AT nasa DOT gov

Dr. Mihoko Yukita Dr. Mihoko Yukita began her career in astrophysics at the Chandra X-ray Center in Cambridge, MA where she assisted observers through the Chandra Director's Office. She moved to the University of Alabama in Huntsville where she received her Ph.D in physics working with the X-ray Astronomy group at Marshall Space Flight Center. She then studied diffuse X-ray emission from the central regions of nearby galaxies as a post-doctoral fellow at the University of Alabama in Tuscaloosa. Currently, she holds a post-doctoral position at Johns Hopkins University as a member of the NuSTAR starburst galaxy science group. Her research concerns the multi-wavelength study of stellar feedback in individual star-forming regions in nearby galaxies to assess the energy and momentum balance on local scales and to investigate how host galaxy structure and evolution are affected by feedback.

Dr. Neven Vulic

neven.vulic AT nasa DOT gov

Dr. Neven Vulic Dr. Neven Vulic received his PhD in astronomy from The University of Western Ontario in June 2016, working with Prof. Pauline Barmby and Prof. Sarah C. Gallagher on multiwavelength studies of X-ray populations in nearby galaxies. He is currently a CRESST/UMCP postdoctoral associate at NASA/GSFC. By exploiting multiwavelength data, with an emphasis on X-ray observations from Chandra, NuSTAR, and XMM-Newton, Neven is interested in explaining the properties associated with the formation and evolution of X-ray binaries in different environments. Dr. Vulic supports the ESA-led ATHENA mission by developing the science case for transients and X-ray binaries in nearby galaxies using the wide-field imager instrument. Dr. Vulic also studies X-ray emission from galaxies in the local Universe using data from eROSITA, one of the instruments on the Spektr-RG observatory launched in July 2019.

Former Group Members

Dr. Vallia Antoniou

vantoniou AT cfa.harvard.edu

Dr. Vallia Antoniou Dr. Vallia Antoniou got her PhD from the University of Crete, Greece in 2008, having worked at SAO with Andreas Zezas and Despina Hatzidimitriou. From there, she moved to Iowa State University first as a postdoctoral research associate working with Massimo Marengo and then (2010-2013) as an affiliate Assistant Professor. In 2013 she returned at SAO as a postdoctoral fellow working with Jeremy Drake and Andreas Zezas. Currently, she is the Project Scientist of a Chandra X-ray Visionary Project overseeing all technical and scientific aspects, including source detection and characterization. Her main research is focused on the multi-wavelength (X-ray, optical, IR) study of X-ray binary populations in nearby star-forming galaxies with the aim to understand and constrain the parameters that affect their formation and evolution (such as the age and metallicity of the stellar populations, and the star formation properties of their galactic environment). She is a member of the following science working groups: NuSTAR's "Starburst Galaxies and Local Group Galaxies", Spitzer's "SAGE-Spec" and Athena's "SWG3-Observatory". Vallia Antoniou's CV can be found HERE.

Dr. Leigh Jenkins

Dr. Leigh Jenkins Dr. Leigh Jenkins was a postdoctoral research scientist in the X-ray Laboratory at NASA/GSFC. She received her Ph.D. in Astronomy from the University of Leicester in the UK in 2005, and a Master of Science degree in Astrophysics from University College London in 2001. Leigh's current research interests involve a wide variety of phenomena in extragalactic astronomy at many wavelengths. These include X-ray binaries/ultraluminous X-ray sources in nearby star-forming galaxies, the X-ray properties of starburst galaxies, as well as the nature of nuclear X-ray activity in local barred and unbarred galaxies. She has also conducted a study of the near-infrared properties of thousands of galaxies in the Coma cluster. Leigh is currently working on the X-ray SINGS survey, which will characterize the X-ray emission from a diverse sample of &mt; 50 nearby galaxies, and relate this to galaxy properties measured at ultraviolet, infrared and optical wavelengths. Currently, Dr. Jenkins works as a Commissioning Editor at IOP Publishing.

Dr. Bret Lehmer

Dr. Bret Lehmer Dr. Bret Lehmer was an Einstein Postdoctoral Fellow, working at Johns Hopkins University and Goddard Space Flight Center since 2009. He received undergraduate degrees in Physics and Astronomy from the University of Iowa and completed his PhD in Astronomy and Astrophysics from Penn State University in 2007. From 2007-2009 he worked at Durham University for the United Kingdom's Science and Technology Facilities Council as a Research Fellow. His main research utilizes deep X-ray observations with the Chandra Observatory to study populations of distant galaxies and supermassive black holes. Currently, Dr. Lehmer is an Assistant Professor at University of Arkansas.

Dr. Barb Mattson

Dr. Barb Mattson Dr. Barb Mattson completed her Ph.D. in astronomy at the University of Maryland. Her Ph.D. thesis research concentrated on X-ray spectral analysis of Seyfert galaxies, with a particular eye on how the results could be interpreted (or not) in the context of the standard AGN model. She has worked at Goddard Space Flight Center for 10 years, starting as a graduate student, pausing to work as a support scientist for several NASA missions, including Swift, Integral and Constellation-X, and finally doing dual duty as a contractor and grad student to finish her Ph.D. Currently, Dr. Mattson works at Goddard Space Flight Center as the Acting Education and Public Outreach (E/PO) Lead for NASA's Physics of the Cosmos and Cosmic Origins Programs, Acting E/PO Lead for the High Energy Science Archive Research Center (HEASARC), and E/PO Lead for the Suzaku and Astro-H missions at GSFC.

Dr. Malachi Tatum

Dr. Malachi Tatum Malachi Tatum earned his Ph.D. at the University of Maryland, Baltimore County in November 2013, having worked with Jane Turner on the importance of the Compton-thick, X-ray reprocessor in active galactic nuclei (AGN). This work included modeling selected Seyfert galaxies using a Compton-thick, accretion disk wind and understanding the spectral properties of a hard X-ray-selected sample in context of reflection-dominated and absorption-dominated models. Malachi joined the Astrophysics Science Division at Goddard Space Flight Center as a NASA Postdoctoral Program (NPP) fellow in November 2013 under the supervision of Andy Ptak. He is focused on using the hard X-ray bandpass as a proxy for understanding the underlying powerlaw continuum of active galactic nuclei and exploring how Compton-thick absorption in the X-ray band affects the energy budget of these systems, both offering insight into understanding the link between black hole mass and the galactic bulge properties. He also has interest in the connection between starbursts and active galactic nuclei.

Dr. Daniel Wik

Dr. Daniel Wik Dr. Daniel Wik received his Ph.D. in astronomy from the University of Virginia in Dec. 2010, working on the physical and cosmological implications of inverse Compton (IC) processes in galaxy clusters with Dr. Craig Sarazin, which made use of data from hydrodynamical simulations and from the Suzaku, Swift, and XMM-Newton observatories. At GSFC as an NPP fellow, he got involved with the hard X-ray NuSTAR mission, including the ground calibration effort of NuSTAR's optics and target planning for the galaxy cluster and starburst galaxy science working groups. In between failing to find IC emission in galaxy clusters, Dan studies the hard X-ray emission from binary populations in nearby galaxies such as M31, M82, and NGC 253 (where he couldn't help but also search for an IC signal, which he unsurprisingly failed to find, yet again). His work on galaxies and clusters of galaxies with NuSTAR led him to develop the nuskybgd background tool and analysis software to decompose the emission of diffuse and/or mildly confused point sources.