New paper published and highlighted by Revista Galileu

Our paper VLT/XShooter spectroscopy of Lyman Break Analogs: direct method O/H abundances and nitrogen enhancements (Loaiza-Agudelo, Overzier & Heckman) was published in The Astrophysical Journal. This paper represents the thesis work of Maryory Loaiza Agudelo, who obtained her PhD at the Observatório Nacional in June, 2019.Screen Shot 2020-04-10 at 16.46.02

The above figure presents the main conclusion of the paper. It shows that the interstellar medium in a class of nearby starburst galaxies known as “Lyman break analogs” has lower oxygen-over-hydrogen (O/H) ratios both expected for their stellar mass and expected based on their nitrogen-over-oxygen (N/O) ratios. Both these facts are most easily explained if these galaxies recently experienced a large influx of relatively metal poor gas (rich in hydrogen but poor in oxygen and nitrogen). This finding agrees well with other facts about these galaxies, and may explain why they are able to produce high rates of star formation.

A more accessible summary for the public can be found on the website of  the Observatório Nacional and in Revista Galileu. The original paper can be found on ApJ or arXiv.

Press Release: Oldest Galaxy Protocluster forms “Queen’s Court”

Recently, using the Subaru, Keck, and Gemini Telescopes, we discovered a collection of 12 galaxies in the constellation Cetus which existed about 13.0 billion years ago. This is the earliest protocluster ever found. One of the 12 galaxies is a giant object, known as Himiko, which was discovered a decade ago by the Subaru Telescope and named for a legendary queen in ancient Japan. This discovery suggests that large structures such as protoclusters already existed when the Universe was only about 800 million years old, 6 percent of its present age. Read the full press release in English from NAOJ here and in Portuguese from ON here. A preprint of the paper by Harikane et al. can be found here.


Advanced School on First Light: stars, galaxies and black holes in the epoch of reionization

After almost one year of preparations, we can look back at a very successful and highly rewarding event held from July 28 to August 7 (2019) at IAG/USP in São Paulo. The school welcomed 100 international students that followed 8 courses from international experts covering topics related to the epoch of reionization, the first stars and galaxies, the formation of supermassive black holes and more. For details, including lecture slides and many photos, please visit the school website: