University of Cambridge
Kavli Institute for Cosmology
Madingley Road
United Kingdom

Latest News

Below I list new science results and snippets of my ongoing research on distant galaxies in the early Universe.

25 July 2018

The gas conditions of the first galaxies with ALMA!

I am very excited to have been awarded new telescope time on the Atacama Large Millimetre Array (ALMA) to study the interstellar gas in galaxies just 800 million years in cosmic time. Not just one, but two proposals of mine were ranked at the highest priority. I will use this new ALMA time to study the low-density, ionised gas in two galaxies that I previously studies with ALMA in order to determine their extreme distance, such that we are looking 12.9 billion years back in time to see them.

4 July 2018

X-shooter spectroscopy on RCS 0224-0002

I have been awarded (top priority) telescope time on the European Very Large Telescope in Chile. I will be studying the peculiar sources of ionization that I've found in a distant (z~5) galaxy seen with the amplification power of the strong lensing cluster RCS 0224-0002. I will use the X-shooter spectrograph to zoom in on the hot gas in this source that gets hit by an intense radiation field. The observations, which will be taken in the spring, will reveal if massive stars or an accreting black hole are generating this radiation.

6 Apr 2018

EWASS Liverpool

This week, I delivered a planery lecture at the European Week of Astronomy and Space Science, EWASS 2018, as part of the MERAC prize awarded by the European Astronomical Society. The Arena and Convention Centre impressive auditorium - with seating for up to 3000 people - is by far the biggest location I have ever been on stage, a nerve-wrecking experience! Later in the week I organised a special session on the high-redshift Universe, with lots of great talks from up and coming young scientists! From the Presidents reception at the St George’s Concert Hall to the impressive venue at the Liverpool Docks this was an wonderful (though exhausting!) week.

22 Feb 2018

MERAC prize

I feel incredibly honoured to have been awarded the 2018 MERAC prize for Best Doctoral Thesis in observational Astrophysics by the European Astronomical Society! This generous prize is awarded for my work on the observational characterisation of the physical properties of the galaxies that formed in the first billion years of cosmic time. Read more about it here or here.

11 Jan 2018

A new spin on the early Universe

My new paper, published in Nature, demonstrates that we can use the Atacama Large Millimetre Array (ALMA) not just to identify galaxies in the very early Universe, but to measure the velocity structure of galaxies in the early Universe for the first time! We infer that these galaxies are spinning around their centre, similar to disk galaxies seen at least 2 billion years later in cosmic time. View the paper here or read the press coverage by the BBC, Forbes, IFLscience or Sky & Telescope.

01 Sept 2017

European Week of Astronomy and Space Science

I am organising a special session with the topic 'Exploring the high-redshift Universe in the year of JWST' at the European Week of Astronomy and Space Science (EWASS), which will be held in April 2018 in Liverpool (EWASS2018). With the launch of the James Webb Space Telescope now tantalisingly close, we will review the state of current research at the early Universe frontier and we will look forward to the revolution of this field in the Webb era.

27 July 2017

Zooming in on a galaxy in the early Universe

We recently obtained stunning success with my observations taken with the Atacama Large Millimetre Array (ALMA; to appear in Nature in January - stay tuned!) which I used to confirm the redshift of two galaxies in the Epoch of Reionization and furthermore detect the velocity structure of such galaxies for the first time! I have now been granted more time with ALMA to zoom in on one of these galaxies to obtain the most detailed ever view of a galaxy just 800 million years after the Big Bang. Would this distant galaxy already look somewhat like the well-organised disk of the Milky Way?

02 March 2017

News & Views highlight in Nature Astronomy

My recently accepted paper featured in the News and Views article 'Early Universe: Through the looking glass' in Nature Astronomy. The article highlights our finding of a large number of distant emission line galaxies, by looking through the gravitational lens RCS 0224 - a cluster of galaxies that has such mass that it can bend light around itself and create a "looking glass" on the sky. You can read the story here.

27 Jan. 2017

Paper accepted!

I've written a paper on the distant galaxies that can be found when looking through the gravitational lens RCS 0224-0002 with the Hubble Space Telescope and the MUSE spectrograph on the European Very Large Telescope. In particular, I've studied one extremely magnified galaxy, just 1.2 billion years after the Big Bang, with an entended hydrogen gas halo around it. We've discovered what is likely a population of stars that are extremely young and massive, with an extreme radiation field that impacts on the gas around them, creating an aboundance of four times ionised Carbon that we can study with our spectrograph - a very rare occurance in our local cosmic environment! The paper will be published in the Monthly Notices of the Royal Astronomical Society and can be found here.

25 Jan. 2017

Gearing up for the James Webb Space Telescope

I'm extremely excited to have joined a new science team that is preparing a future survey with the James Webb Space Telescope (JWST). 'Webb' will be launched in November 2018 and it is often considered the successor of 'Hubble' - the Hubble Space Telescope. Our team will exploit the guaranteed time observations with the Near Infrared Spectrograph, build by the European Space Agency, and we will use it to study the very first galaxies and their evolution during the first few billion years of cosmic time. Information about the instrument can be found here and the survey here.

11 Oct. 2016

Ada Lovelace day

The Ada Lovelace day is the international celebration day of the achievements of women in science, technology, engineering and maths (STEM). This year I was part of the Leading Ladies in Stem panel discussion, organised by Tech for Life at Campus North in Newcastle. There was lots to learn from women across the generations who each faced their challenges!

10 July 2016

Royal Society Summer Science Exhibition

The Durham Astronomy department has put together an impressive exhibit for the Royal Society Summer Science festival titled 'Galaxy Makers: how do you build a galaxy?'. I've contributed to the shooting of the introduction video; for more information on the exhibit and to see the full video, please see here.

30 June 2016

Research grant and move to Cambridge

I have been awarded a Rubicon grant by the Netherlands Organisation for Scientific Research (NWO) for a 2 year research program which I will conduct at the Astrophysics department of the University of Cambridge. I'm excited for this new move and the research that I've planned, which will include new studies with the Multi Unit Spectroscopic Explorer (MUSE) and the Atacama Large Millimetre Array (ALMA)!

22 Apr. 2016

Filming for Cosmic Front documentary

I've spent the last two days with a professional filmcrew to shoot scenes for the astronomy documentary series Cosmic Front on the national public broadcaster of Japan, NHK. This popular science program draws as many as 1 million viewers! We filmed in Durham Castle, the Institute of Advanced Study and along the Durham Heritage coastline.

16 March 2016

Hubble time for RCS 0224-0002

A few months ago, I made a peculiar discovery when studying the MUSE data of the strongly lensed z~5 galaxy behind the strong lensing cluster RCS 0224-0002: this galaxy produces wide-spead, narrow, but high-equivalent width CIV 1550A emission, a very uncommon line in star-forming galaxies in the local Universe. The source that produces this line is most likely 'hot', i.e. it produces a lot of highly-ionizing photons. This is interesting because sources of a lot of ionizing radiation could play a crucial role in reionizing the Universe at z>6. Excitingly, I have received observing time on the famous Hubble Space Telescope to study this object! Hopefully we will soon be able to determine what type of sources produce the CIV emission in RCS 0224-0002.

10 March 2016

GN-z11 receives worldwide interest

I was recently part of the team led by Pascal Oesch that confirmed the galaxy GN-z11, the most distant galaxy known to date, with the Hubble Space Telescope: This extremely distant galaxy is seen only 400 million years after the Big Bang and is many times brighter than we had ever expected such young galaxies to be! Watch this cool movie and view the paper here. The spectacular discovery of GN-z11 was reported all over the world, with more than 1000 detected online press clippings and an estimated reader circulation of ~800 million people!!

15 Dec. 2015

Lya emitters behind RCS 0224-0002

Analysing the extensive MUSE dataset on the strong lensing cluster RCS 0224-0002 I have serendipitously found a large number of Lya emitting sources. Lya is a spectral line emitted by the hydrogen gas present throughout star-forming galaxies. Using the unique field-of-view and wavelength range that MUSE has to offer, I find a significant number of these sources out the redshift z=6.56, 840 million years after the Big Bang. The power of gravitational lensing made this discovery possible in a mere 3.5 hours of integration on source.

27 Nov. 2015

Papers on Ha in z~4-5 galaxies submitted

Two related papers appeared on the arXiv this week that I am heavily involved in. In short, we have used the Spitzer/IRAC colors of galaxies to find a new way of determining the rate of star formation in distant galaxies. These star-formation rates can tell use all sorts of interesting things about these galaxies, such as their star-formation history and Lyman-continuum photon production efficiency. The papers are submitted to ApJ; Smit et al., 2015b and Bouwens, Smit et al., 2015.

23 Oct. 2015

Science book review

Together with my father, Prof. Jan Smit, I have reviewed Lisa Randall's latest popular science book called 'Dark Matter and the Dinosaurs' for Science Magazine. Curious? You can find our review here.

7 Sept. 2015

Student paper submitted

I am very proud of my master student Nicholas Rasappu who submitted his first lead-author paper this week called "Mean Halpha+[NII]+[SII] EW Inferred for Star-Forming Galaxies at z=5.1-5.4 Using High-Quality Spitzer/IRAC Photometry". Nicholas worked with me for a year on his Masters research project in 2013-2014 and studied distant galaxies and the distribution of their Spitzer/IRAC colors as function of redshift. His thesis was brilliant and we've been working towards finishing up this paper ever since. The paper appeared on the arXiv today; Rasappu, Smit et al., 2015.

03 Sept. 2015

EGS8p7 breaks cosmic record

So short after the last record on the highest redshift galaxy we have done it again: our team of scientists led by Adi Zitrin has detected Lyman alpha in a distant galaxy, confirming it's impressive redshift of z=8.7! Just 600 million years after the Big Bang. Read about the story on the Daily Mail, the Mirror and the Independent

28 Aug. 2015

MUSE data on Abell 1689 in!

After the strong lensing cluster RCS 0224-0002 we have now also received MUSE data on Abell 1689, which we will use to study some of the strongest lensed high-redshift galaxies known with amazing detail. MUSE observes the rest-frame ultraviolet spectra of these magnified sources, which will allow us to study the spatially resolved outflowing gas of distant galaxies.

09 June 2015

Astronomy & Geophysics special edition

Together with my colleages Stephen Wilkins, Rebecca Bowler, Joseph Caruana, Illian Iliev, Jonathan Pritchard and Elizabeth Stanway I have written a special edition of Astronomy & Geophysics on the topic of the 'Cosmic Dawn'. My article 'Cosmic lenses for the distant Universe' covers the use of gravitational lensing for high-redshift science. Find the introduction article by Stephen Wilkins and Elizabeth Stanway here and my article on lensing here.

5 May 2015

EGS-zs8-1 sets a new redshift record

After identifying galaxies at redshift z~6.8 with Spitzer (see below), we have expanded our HST+Spitzer searches to redshift z~7-9 using the stand-out red Spitzer/IRAC colors of these galaxies. The first follow-up spectroscopy of these sources has proven highly succesful, with one confirmed galaxy at z=7.48 (Roberts-Borsani, et al., 2015) and a redshift-record-breaking galaxy at z=7.73!! Read the paper here and check out the news items here: the New York Times LA Times NBC the Daily Mail NPR the Independent

15 April 2015

The elusive properties of Dark Matter

With a team is of scientists led by Richard Massey we have investigated a rare event in the Universe: the collison of multiple objects with large quantities of Dark Matter. We have found a small, but measurable (!) interaction within the Dark Matter component of this collision. This is the first time any interaction of Dark Matter has been measured and hopefully this can lead to further investigations of the properties of this fundamental component of the Universe! The results are published in MNRAS, Massey, Williams, Smit, et al., 2015. The press release of our results generated some nice coverage from Al Jazeera and the BBC!

1 March 2015

Paper on z~7 galaxies published

I have written a new paper on HST+Spitzer selected sources at redshift z~7. These sources are expected to have extreme [OIII]5007A equivalent widths, a feature that allows us to pinpoint the redshift of these objects with high precision. Furthermore, we show that these objects are very common, representing ~50% of the UV-selected sources at this redshift; this is really good news for future observations with the James Webb Space Telescope as [OIII] will be one of the most common features targeted for obtaining spectroscopic redshifts and measuring phsyical properties such as gas phase metallicity! The paper is published in ApJ; Smit et al., 2015.