Employment & Education:
Dr. Dan Coe is an ESA/AURA Astronomer at the Space Telescope Science Institute (STScI) and Johns Hopkins University (JHU) in Baltimore, MD. Dan discovers and studies distant galaxies in the early universe using Hubble and the James Webb Space Telescope (JWST). He is currently leading two JWST programs that use gravitational lensing by massive galaxy clusters to magnify the distant universe. The beautiful new images, data, and science results are available via his Cosmic Spring team website.
Dan's JWST programs are studying distant lensed galaxies and stars discovered with Hubble, in addition to making new discoveries. One program is studying Earendel, the most distant star known, observed a billion years after the Big Bang at redshift z ~ 6. Earendel was discovered by Dan's former JHU PhD student Brian Welch. It is magnified by thousands within the most highly magnified galaxy observed in the first billion years, named the Sunrise Arc. Brian is leading the JWST science papers on Earendel.
Dan's other JWST program is studying MACS0647-JD, one of the most distant galaxies ever discovered with Hubble at z ~ 11, observed 97% of the way back to the Big Bang when the universe was just 400 million years old. Dan discovered MACS0647-JD in 2013. Dan's current JHU grad student Tiger Hsiao is leading the JWST science papers on MACS0647-JD.
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 used Hubble and gravitational lensing to efficiently discover distant galaxies 97% of the way back to the Big Bang. JWST is now enabling them to study these objects in detail and reveal objects that existed even earlier in the universe's history, during the first 400 million years.
As part of his job at STScI, Dan also 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.
Dan is excited to lead two JWST programs:
and be a co-investigator on: