Bio

https://www.stsci.edu/stsci-research/research-directory/dan-coe

Dr. Dan Coe is an ESA/AURA Astronomer at the Space Telescope Science Institute (STScI) in Baltimore, MD. Dan discovers and studies the most distant galaxies known using the Hubble and Spitzer Space Telescopes and soon the James Webb Space Telescope (JWST)! He uses gravitational lensing by massive galaxy clusters to magnify the distant universe. Dan's PhD student Brian Welch recently discovered Earendel, the most distant star known at z ~ 6 (a billion years after the Big Bang). In 2013, Dan discovered MACS0647-JD, a strong candidate for the most distant galaxy known at z ~ 11, observed 97% of the way back to the Big Bang when the universe was just 400 million years old. Later this year 2022, JWST will observe both Earendel and MACS0647-JD. Dan is leading both observing programs and making all data public immediately along with data analysis tools.

As part of his job at STScI, Dan provides support for other astronomers using and preparing to use Hubble and JWST. As an instrument scientist for the JWST Near Infrared Camera (NIRCam), Dan wrote much of that instrument’s user manual in JDox (JWST Documentation), developed more efficient dither patterns for NIRCam observations, and has created public JWST data analysis tools (JDAT Python notebooks) for astronomers to study galaxies in NIRCam images. Dan's notebooks measure photometry and photometric redshifts, or rough distances to galaxies, something Dan has worked on since analyzing the Hubble Ultra Deep Field in 2006.

Earendel was a science highlight of the Reionization Lensing Cluster Survey (RELICS), a 188-orbit Hubble Treasury Program that Dan led as Principal Investigator (PI). RELICS observed 41 clusters and delivered many of the best and brightest galaxies known in the universe’s first billion years (z ~ 6 – 10). These galaxies are bright enough for detailed study with JWST imaging and spectroscopy.

In addition to leading RELICS, Dan was also a co-investigator on the Hubble Multi-Cycle Treasury Program CLASH (Cluster Lensing And Supernova survey with Hubble) that yielded MACS0647-JD. Dan also successfully advocated for lensing clusters to be included in the Hubble Deep Fields Initiative, which became the Frontier Fields. Dan coordinated astronomers' gravitational lens modeling efforts for the Frontier Fields.

Earlier in his career, as a grad student Dan was a member of the HST ACS Guaranteed Time Observations (GTO) science team. He measured Bayesian photometric redshifts of galaxies in the Hubble Ultra Deep Field (in 2006) and derived the most detailed dark matter map to date (in 2010) of a galaxy cluster based on his strong lensing analysis of Abell 1689. Dan received his PhD from Johns Hopkins, splitting his time between there and the Andalusian Astrophysics Institute (IAA) in Granada, Spain. He went on to a Caltech postdoctoral scholar position at NASA’s Jet Propulsion Laboratory (JPL) where he studied cosmological constraints from gravitational lens time delays. For his second postdoc, he worked on CLASH at STScI before joining the STScI staff as an astronomer in 2013.

Dan and his colleagues have used gravitational lensing to efficiently discover distant galaxies 97% of the way back to the Big Bang. We have yet to observe a single object that existed earlier than that, during the universe’s first 400 million years. The James Webb Space Telescope (JWST) will enable astronomers to begin writing this first 3% of our cosmic history. Dan predicts that gravitational lensing will be the key to discovering the first galaxies with JWST.


Dan is excited to lead two JWST programs:

  • GO 1433 studying the z=11 candidate for most distant galaxy known: MACS0647-JD

  • GO 2282 studying the most highly magnified galaxy known in the first billion years at z=6

and be a co-investigator on:

  • GTO 1176 "PEARLS" (PI Rogier Windhorst) observing 7 galaxy clusters (among other things)

  • GO 2561 "UNCOVER" (PI Ivo Labbe; Co-PI Rachel Bezanson) obtaining the deepest JWST data on any galaxy cluster in Cycle 1


Education:

  • 2007 PhD in Astronomy, Johns Hopkins University

  • 1999 BS in Applied and Engineering Physics, Cornell University


Science Interests:

  • When did the first galaxies form? What did they look like? And what were they made of?

  • Galaxy cluster formation, the growth of structure, and cosmological constraints

  • What is dark matter? Lensing constraints on particle properties


Research Topics:

  • High-Redshift Galaxies

  • Galaxy Formation and Evolution

  • Gravitational Lensing

  • Galaxy Clusters