Related papers: The galaxy ancestor problem
Although the universe at redshifts greater than six represents only the first one billion years (<10%) of cosmic time, the dense nature of the early universe led to vigorous galaxy formation and evolution activity which we are only now…
The effects of galaxy selection on our ability to constrain the nature of weak Ly\alpha absorbers at low redshift are explored. Current observations indicate the existence of a population of gas-rich, low surface brightness (LSB) galaxies,…
The size-mass galaxy distribution is a key diagnostic for galaxy evolution. Massive compact galaxies are potential surviving relics of a high-redshift phase of star formation. Some of these could be nearly unresolved in SDSS imaging and…
Submillimetre galaxies (SMGs) are among the most luminous dusty galaxies in the Universe, but their true nature remains unclear; are SMGs the progenitors of the massive elliptical galaxies we see in the local Universe, or are they just a…
Massive galaxies, such as nearby ellipticals, have relatively low number densities, yet they host the majority of the stellar mass in the universe. Understanding their origin is a central problem of galaxy formation. Age dating of stellar…
We present Very Large Array ({\sc vla}) and Westerbork Synthesis Radio Telescope ({\sc wsrt}) 21-cm H{\sc i} observations of 19 late-type low surface brightness (LSB) galaxies. Our main findings are that these galaxies, as well as having…
The Hubble Deep Fields continue to be a valuable resource for studying the distant universe, particularly at z>2 where their comoving volume becomes large enough to encompass several hundred L* galaxies or their progenitors. Here I present…
We stack Spitzer 24 micron images for ~7000 galaxies with 0.1<z<1 in the Chandra Deep Field South to probe the thermal dust emission in low-luminosity galaxies over this redshift range. Through stacking, we can detect mean 24 micron fluxes…
Recent optical observations have led to a significant progress in our understanding of galaxy formation and evolution. However, our view on the deep universe is currently limited to the starlight which directly escapes from high-redshift…
The quest to discover the most distant galaxies has developed rapidly in the last decade. We are now exploring redshifts of 6 and beyond, when the Universe was less than a billion years old, an epoch when the previously-neutral…
We have obtained spectroscopic redshifts using the Keck-I telescope for a sample of 73 submillimeter (submm) galaxies for which precise positions are available. The galaxies lie at redshifts out to z=3.6, with a median redshift of 2.2. The…
In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty, starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been…
The Lyman decrement associated with the cumulative effect of HI in QSO absorption systems along the line of sight provides a distinctive feature for identifying galaxies at z>2.5. The Hubble Deep Field (HDF) observations offer the…
The presence of massive galaxies at high $z$ as recently observed by JWST appears to contradict the current $\Lambda$CDM cosmology. Here we aim to alleviate this tension by incorporating uncertainties from three sources in counting…
We have discovered a highly significant over-density of galaxies at z=2.300+/-0.015 in the course of a redshift survey designed to select star-forming galaxies in the redshift range z=2.3+/-0.4 in the field of the bright z=2.72 QSO…
JWST observations have suggested that some high-redshift galaxies may be ultra-massive, thereby challenging standard models of early galaxy formation and cosmology. We analyse the stellar masses using different modelling assumptions and…
We use deep NIRSpec spectroscopic data from the JADES survey to derive the star formation histories (SFHs) of a sample of 200 galaxies at 0.6$<$z$<$11 and spanning stellar masses from $\rm 10^6$ to $\rm 10^{9.5}~M_\odot$. We find that…
We use a sample of 90 spectroscopically-confirmed Lyman Break Galaxies with H-alpha and 24 micron observations to constrain the relationship between rest-frame 8 micron luminosity, L(8), and star formation rate (SFR) for L* galaxies at z~2.…
Determing the nature of the bright sub-mm sources and their role in the process of galaxy formation is likely to be a major focus of extra-galactic research over the next few years. In particular, we would like to know if these sources are…
Although there has been much progress in understanding how galaxies evolve, we still do not understand how and when they stop forming stars and become quiescent. We address this by applying our galaxy spectral energy distribution models,…