Romain A. Meyer

Romain A. Meyer

Maitre-Assistant (Research and Teaching Fellow)

University of Geneva

Welcome to my homepage!

I’m Romain, a postdoctoral researcher at Geneva Observatory (UNIGE) interested in galaxies and black holes in the first billion years of the Universe. I am mainly an observer who uses the largest ground- and spaced-based telescopes to detect the most distant objects and understand how the epoch of cosmic reionisation unfolded.

Interests

  • Cosmic Hydrogen Reionisation
  • First Galaxies and Quasars
  • IGM/CGM evolution
  • Machine Learning

Education

  • PhD in Astrophysics, August 2020

    University College London

  • Msc in Physics, 2017

    École Polytechnique Fédérale Lausanne

  • BSc in Physics, 2015

    École Polytechnique Fédérale Lausanne

Recorded Talks

Learning (from) Quasars with VAEs

Demonstrating the power of Variational Auto-Encoders to reconstruct quasar spectra, generate realistic mock SDSS quasars and infer physical parameters directly from the latent space of the autoencoder.
Feb 2, 2022 5:00 PM — 5:15 PM
Romain A. Meyer
Video

Constraining galaxy overdensities around three z~6.5 quasars with ALMA and MUSE

In this talk I present the results of a search for overdensities of galaxies around quasars at z>6 using MUSE and ALMA. The results are published here: https://iopscience.iop.org/article/10.3847/1538-4357/ac4f67
Jan 25, 2022 9:50 AM — 10:05 AM Online
Romain A. Meyer
Video

Measuring the escape fraction of ionising photons of z~6 galaxies

Here I’m discussing new constraints on the ionising output of z~6 galaxies, putting together the results of three papers published during my thesis.
Jul 7, 2020 10:00 AM — 10:15 AM Online
Romain A. Meyer
Video

Mauna Kea

Subaru, Keck I&II and IRTF telescopes

Onsala Observatory

25m radio telescope

Keck Telescope

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First-Author Publications

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All IGM Reionisation High-z Quasars High-z galaxies ML & Data mining

NOEMA reveals the true nature of luminous red JWST z>10 galaxy candidates

The first year of JWST has revealed a surprisingly large number of luminous galaxy candidates beyond z>10. While some galaxies are …
R.A. Meyer, L. Barrufet, L.A. Boogaard, P.A. Oesch, F. Walter
PDF DOI

ALMA 300 pc Resolution Imaging of a z = 6.79 Quasar: No Evidence for Supermassive Black Hole Influence on the C II Kinematics

We present Atacama Large Millimeter/submillimeter Array (ALMA) [C II] 158 μm and dust continuum observations of the z = 6.79 quasar …
R.A. Meyer, M. Neelema, F. Walter, B. Venemans
PDF DOI

Constraining Galaxy Overdensities around Three z 6.5 Quasars with ALMA and MUSE

We quantify galaxy overdensities around three high-redshift quasars with known [CII] 158 μm companions: PJ231-20 (z = 6.59), PJ308-21 …
R.A. Meyer, R. Decarli, F. Walter, Q. Li, R. Wan, C. Mazzuchelli, E. Bañados, E. P. Farina, B. Venemans
PDF DOI

Physical constraints on the extended interstellar medium of the z=6.42 quasar J1148+5251: CII 158um, NII 205um and OI 146um observations

We report new Northern Extended Millimeter Array (NOEMA) observations of the CII, NII and OI atomic fine structure lines and dust …
R.A. Meyer, F. Walter, C. Cicone, R. Decarli, R. Neri, M. Novak, A. Pensabene, D. Riechers, A. Weiss
PDF DOI

Double-peaked Lyman-alpha emission at z=6.803: a reionisation-era galaxy self-ionising its local H II bubble

We report the discovery of a double-peaked Lyman-alpha profile in a galaxy at $z=6.803$, A370p z1, in the parallel Frontier Field of …
R.A. Meyer, N. Laporte, R.S. Ellis, A. Verhamme, T. Garel
PDF DOI

The role of galaxies and AGN in reionising the IGM - III : IGM-galaxy cross-correlations at $z\sim 6$ from 8 quasar fields with DEIMOS and MUSE

We present improved results of the measurement of the correlation between galaxies and the intergalactic medium (IGM) transmission at …
R.A. Meyer, K. Kakiichi, S.E.I. Bosman, R.S. Ellis, N. Laporte, B.E. Robertson, E.V. Ryan-Weber, K. Mawatari, A. Zitrin
PDF DOI

New Constraints on Quasar Evolution: Broad Line Velocity Shifts over 1.5≲z≲7.5

We present the results of a model-independent investigation of the rest-frame UV spectra from a comprehensive sample of $394$ quasars …
R.A. Meyer, S.E.I. Bosman, R.S. Ellis
PDF DOI

Quasi-stellar objects acting as potential strong gravitational lenses in the SDSS-III BOSS survey

We present a sample of 12 quasi-stellar objects (QSOs) that potentially act as strong gravitational lenses on background emission line …
R.A. Meyer, T. Delubac, J.-P. Kneib, F. Courbin
PDF DOI

The role of galaxies and AGNs in reionizing the IGM - II. Metal-tracing the faint sources of reionization at 5 ≲ z ≲ 6

We present a new method to study the contribution of faint sources to the UV background using the 1D correlation of metal absorbers …
R.A. Meyer, S.E.I. Bosman, K. Kakiichi, R.S. Ellis
PDF DOI