Research Interests


NuSTAR is the first focusing hard X-ray satellite in orbit, providing more than two orders of magnitude improvement in sensitivity as compared to previous high-energy missions working at similar energies. The primary science goals of NuSTAR are broad, and include studying a range of high-energy sources, including black holes, supernovae explosions, neutron stars, relativistic jets, and the Sun.

Accreting Compact Objects

Accreting compact objects, such as black holes and neutron stars bend and twist space-time, or contain degenerate matter with unique properties. We use X-ray telescopes like NuSTAR (among others) to observe the high-energy emission from these objects in binary systems, in which the compact object is gravitationally tied to a stellar companion.


Ultraluminous X-ray Sources (ULXs) are X-ray binaries in other galaxies undergoing such extreme accretion that they are some of the most luminous X-ray sources in the nearby Universe outside of the centers of galaxies.

More Research!

There's a whole lot more for NuSTAR to look at beyond accreting compact objects and ULXs alone! Click below to hear about some more of the fascinating topics that our team devote their time to exploring.

Group Members

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Upcoming and Recent Group Activity

  • July 20

    Brian gives public lecture

    Staff scientist Brian Grefenstette gave a public lecture to the Night Sky Network about NuSTAR and the exciting X-ray science it has covered in its 10 years of operation. Read more about the talk and watch the recording here!

  • July 18

    Sean successfully defends his Ph.D. thesis!

    Graduate student Sean Pike successfully defended his Ph.D. thesis. Congratulations Dr. Pike!

  • July 14

    Riley's paper is accepted for publication!

    Postdoc Riley Connors' paper, titled "The long-stable hard state of XTE J1752-223 and the disk truncation dilemma," has been accepted for publication in ApJ. You can read the full paper here. Congratulations Riley!

  • July 8

    Margaret's paper is accepted for publication!

    Postdoc Margaret Lazzarini's paper on measuring the star formation history in the Triangulum Galaxy has been accepted for publication in ApJ. You can read the full paper here, or check out the awesome Astrobites article on the paper instead! Congratulations Margaret!

  • July 7

    Renee's paper is accepted for publication!

    Postdoc Renee Ludlam's paper, titled " StrayCats II: An Updated Catalog of NuSTAR Stray Light Observations," has been accepted for publication in ApJ. You can read the full paper here, and learn more about the StrayCats project on their website! Congratulations Renee!

  • June 20

    Ten Years of NuSTAR Conference

    Our Caltech group is helping to organize the "Ten Years of NuSTAR" conferenceb in Cagliari, Italy. We cannot wait to see you in beautiful Cagliari and hear about your recent NuSTAR science.

  • June 16

    Hannah's paper is accepted for publication!

    Staff Scientist Hannah Earnshaw's paper, titled "The variability behavior of NGC 925 ULX-3," has been accepted for publication in ApJ. You can read the full paper here. Congratulations Hannah!

  • June 14

    Welcome Summer Students!

    Summer truly begins with the arrival of our SURF and WAVE summer students. This group of undergraduates, both from Caltech and from schools around the world, will work with postdocs and staff scientists on exciting astrophysics research projects.

  • June 13

    Happy 10th Birthday NuSTAR!

    Ten years ago today, NuSTAR successfully launched into orbit and became the first observatory to focus high energy X-rays, opening the door to new exploration of high energy phenomena. We are so proud of NuSTAR's spectacular performance and look forward to more exciting science in the years to come. Learn more about NuSTAR by reading this JPL press release and download a beautiful poster made to commemorate the occasion.