I am a postdoctoral research associate at Caltech's Space Radiation Laboratory

I work with Professor Fiona Harrison and the science operating committee for the high energy X-ray telescope NuSTAR . I completed my Ph.D. at Dartmouth College, where I worked with Professor Ryan Hickox and his Black Holes and Galaxies research group. My research focuses on magnetically driven accretion onto X-ray pulsars. I am particularly interested in modeling the kinematics and geometry of warped accretion disks, such as those found in Her X-1, LMC X-4, and SMC X-1. My pronouns are she/her/hers!

Research: Project Overview

Neutron stars are the dense, highly magnetized cores of massive stars that are left behind after supernova explosions. A neutron star's strong magnetic field accelerates electrons, creating beams of radiation that emanate from the magnetic poles. In a manner similar to a lighthouse signal, this beam of radiation sweeps across space. If this beam intersects Earth, astronomers can detect a burst of light. Because of this behavior, we call such objects pulsars.

Some pulsars, known as accreting pulsars, are formed in binary systems where the companion star sheds gas that is gravitationally attracted to the neutron star. The expelled matter falls towards the pulsar, forming an accretion disk. However, when the infalling matter reaches the pulsar's magnetosphere, the magnetic forces dominate the accretion process. As the gas is confined to the pulsar's magnetic field, the infalling gas heats up and emits X-rays. The process of magnetic accretion, and the response of matter to magnetic fields that are trillions of times stronger than Earth's, is not well understood.

In order to learn more about magnetic accretion mechanisms, I am studying the geometry and kinematics of the warped accretion disks found in sources like Her X-1, LMC X-4, and SMC X-1. Using joint observations from the NuSTAR and XMM-Newton space telescopes, I can use tomography to model the geometry of the disk during its precession.

Research: Published work

ORCID logo https://orcid.org/0000-0002-4024-6967

First Author Publications

Brumback, M.C., Grefenstette, B.W, Buisson, D.J.K., Bachetti, M., Connors, R.,Jaodand, A., Krivonos, R., Ludlam, R., Madsen, K.K., Mastroserio, G., Tomsick, J.A., Wik, D. 2021. 2022. ApJ, 926, 187
“Extending the baseline for SMC X-1’s spin and orbital behavior with NuSTAR stray light”

Brumback, M.C., Hickox, R.C., Fürst, F.S., Pottschmidt, K., Tomsick, J.A., Wilms, J., Staubert, R., Vrtilek, S. 2021. ApJ. 909, 186
"A broad-band X-ray view of the precessing accretion disk and pre-eclipse dip in the pulsar Her X-1 with NuSTAR and XMM-Newton"

Brumback, M.C., Hickox, R.C., Fürst, F.S., Pottschmidt, K., Tomsick, J.A., Wilms, J. 2020. ApJ, 888, 125.
"Modeling the Precession of the Warped Inner Accretion Disk in the Pulsars LMC X-4 and SMC X-1 with NuSTAR and XMM-Newton"

Brumback, M.C., Hickox, R.C., Bachetti, M., Ballhausen, R. Fürst, F.S., Pike, S., Pottschmidt, K., Tomsick, J.A., Wilms, J. 2018. ApJL, 861, L7.
"Discovery of pulsation dropout and turn-on during the high state of the accreting X-ray pulsar LMC X-4"

Brumback, M.C., Hickox, R.C., Fürst, F.S., Pottschmidt, K., Hemphill, P., Tomsick, J.A., Wilms, J., Ballhausen, R. 2018. ApJ, 852, 132.
"A possible phase dependent absorption feature in the transient X-ray pulsar SAX J2103.5+4545."

Contributing Author Publications

Bachetti, M., Heida, M., Maccarone, T., Huppenkothen, D., Israel, G.L., Barret, D., Brightman, M., Brumback, M.C., et al. 2021. Submitted to ApJ.
“The extreme mass transfer and high magnetic field of the first ultraluminous pulsar M82 X-2”

Ludlam, R.M., Grefenstette, B.W., Brumback, M.C., Tomsick, J.A., Buisson, D.J.K., Coughenour, B.M., Mastroserio, G., et al. 2022. ApJ, 934, 1, 59.
"StrayCats. II. An Updated Catalog of NuSTAR Stray Light Observations"

Dage, K., Brumback, M.C., Neilsen, J., Hu, C-P., et al 2022. MNRAS, 514, 2, 5457.
“Monitoring Observations of SMC X-1’s Excursions (MOOSE) I: Program Description and Initial High-State Spectral Results”

Pike, S.N., Negoro, H., Tomsick, J.A., Bachetti, M., Brumback, M.C., et al., 2022. ApJ, 927, 190
“MAXI and NuSTAR observations of a low-luminosity X-ray transient in the GLIMPSE-C01 Cluster”

Staubert, R., Ducci, L., Fürst, F.S., Wilms, J., Rothschild, R.E., Pottschmidt, K., Brumback, M.C., Harrison, F. 2020 A&A, 642, A196.
"Cyclotron line energy in Hercules X-1: stable after the decay"

Bachetti, M., Maccarone, T.J., Brightman, M., Brumback, M.C., Fürst, F.S., Harrison, F.A., Heida, M., Israel, G.L., Middleton, M.J., Tomsick, J.A., Webb, N.A., Walton, D.J. 2019. ApJ, 891, 44.
"All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2 "

Pike, S.N., Harrison, F.A., Bachetti, M., Brumback, M.C., Fürst, F.S., Madsen, K.K., Pottschmidt, K., Tomsick, J.A., and Wilms, J. 2018. ApJ, 875, 144.
"Observing the transient pulsations of SMC X-1 with NuSTAR"

Research: Conferences and presented work

AAS HEAD Meeting #19. March 2022, Pittsburgh, Pa. ( see Poster )

Seminar at McGill University. February 2022. Talk title: "A broad-band X-ray view of accretion disks around neutron stars"

Colloquium at Howard University. October 2021. Talk title: "A broad-band X-ray view of accretion disks around neutron stars"

Seminar at Hamilton College. November 2020. Talk title: "Exploring the physics of accretion onto luminous, magnetized neutron stars"

Seminar at Michigan State University. June 2020. Talk title: "Exploring the physics of accretion onto luminous, magnetized neutron stars"

AAS #235. January 2020, Honolulu, Hi. Talk title: "A broad-band X-ray study of magnetic accretion in neutron star X-ray binaries"

European Week of Astronomy and Space Sciences. 2019, Lyon, France. Talk title: "What can neutron star X-ray binaries tell us about ultra-luminous X-ray pulsars?"

AAS HEAD Meeting. March 2019, Monterey, Ca. ( see Poster )

Are AGN Special? The environmental dependence and global impact of AGN activity. 2018, Durham University, Durham, UK (see Poster)

ULX Pulsar Workshop. June 2018, ESAC, Madrid, Spain. Talk title: "Pulse dropout in LMC X-4: Bridging the gap between accretion properties in Eddington and super-Eddington pulsars"

NERQUAM #28. 2018, Yale University University. Talk title: "Discovery of pulsation dropout and turn-on during the high state of the accreting X-ray pulsar LMC X-4"

AAS HEAD Meeting. August 2017, Sun Valley, Id. (see Poster)

NuSTAR Science Meeting. 2016, Pasadena, Ca. (see Poster)

Hidden Monsters: Obscured AGN and Connections to Galaxy Evolution Workshop. 2016, Dartmouth College (Attended)

AAS HEAD Meeting. 2016, Naples, Fl. (see Poster)

NERQUAM #26. 2016, Brandeis University. Talk title: "Exploring the warped accretion disk around the magnetized neutron star LMC X-4"

NERQUAM #25. 2015, Dartmouth College (Attended)

Read my full CV here.

Teaching

Getting others interested in astronomy is one of the most rewarding parts of my job.

Undergraduate Courses

At Dartmouth College, I enjoyed being a teaching assistant to undergraduate courses in astronomy and physics. The duties of a teaching assistant included holding regular office hours, conducting laboratory experiments, and grading assignments. I have been a TA for Understanding the Universe (Physics 1 and 2), General Physics I and II (Physics 3 and 4), as well as Exploring the Solar System (Astronomy 1), Exploring the Universe (Astronomy 2 and 3), and Astrophysics (Astronomy 74).

Outreach

While in graduate school, I participated in a number of outreach events in the Upper Valley. Along with other astronomy graduate students, I hosted Public Observing at Dartmouth. I also attended the Montshire Museum of Science's anual Astronomy Day as a guest astronomer. I have also spoken at high schools throughout New England on topics from galaxy evolution to the search for extraterrestrial life.

Classroom Experience

As part of my Education minor at Hamilton College, I completed over 100 hours of classroom teaching at Clinton Middle School. I wrote and delivered lessons focusing on Newton's Laws to the seventh grade science class. I enjoyed including exciting demonstrations, such as the bed of nails (shown above) and the rocket bike, in my lessons.

About Me

While research can be time consuming, I enjoy a number of hobbies outside of the office.

Winter

Some of my favorite things about living in New Hampshire for graduate school were the winter sports. I am an avid downhill skier and an aspiring ice hockey player. I played for the Physics and Astronomy intramural hockey team, the Absolute Zeros. Above is a photo of me scoring a goal for our team!

Summer

In the warmer months, and especially since starting at Caltech, I enjoy hiking, kayaking, and going to the beach. When I'm not outside, I enjoy playing board games with friends, drawing, and reading. Currently, my favorite authors are N.K. Jemisin, T. Muir, P. Rothfuss, and B. Sanderson

Education

I got my Ph.D. in Physics and Astronomy from Dartmouth College in 2020. Prior to that, I attended Hamilton College, where I graduated Summa Cum Laude in 2014 with a major in Physics and minors in Mathematics and Education. Click below to view my complete CV.