Related papers: Type III Societies (Apparently) Do Not Exist
A PopIII/Pop II transition from massive to normal stars is predicted to occur when the metallicity of the star forming gas crosses the critical range Z_cr = 10^(-5 +/- 1) Z_sun. To investigate the cosmic implications of such process we use…
The search for extraterrestrial intelligence includes efforts to constrain populations of artificial broadcasts in other galaxies. Previous efforts use individualist methods, searching for single broadcasts with high signal-to-noise ratio.…
We present a method to infer reddenings and distances to stars, based only on their broad-band photometry, and show how this method can be used to produce a three-dimensional dust map of the Galaxy. Our method samples from the full…
We study the intrinsic and observable shapes of approximately 700 star-forming galaxies with stellar masses of $10^8 - 10^{11}$ M$_\odot$ from the FIREbox simulation at $z=0$. We calculate intrinsic axis ratios using inertia tensors…
Galaxy clusters grow by accreting galaxies as individual objects, or as members of a galaxy group. These groups can strongly impact galaxy evolution, stripping the gas from galaxies, and enhancing the rate of galaxy mergers. However, it is…
Matter with an equation of state $p=-\rho/3$ may arise in certain scalar field theories, and the energy density of this matter decreases as $a^{-2}$ with the scale factor $a$ of the Universe. In this case, the Universe could be closed but…
From studying the cosmic microwave background, we know our Universe started out very simple. It was by and large homogeneous and isotropic, with small fluctuations that can be described by linear perturbation theory. In stark contrast, the…
Open clusters have long been used as tracers of Galactic structure. However, without a selection function to describe the completeness of the cluster census, it is difficult to quantitatively interpret their distribution. We create a method…
Population III stars are believed to have been more massive than typical stars today and to have formed in relative isolation. The thermodynamic impact of metals is expected to induce a transition leading to clustered, low-mass Population…
Radio galaxies are the only non-blazar extragalactic objects detected in the VHE (E >100 GeV) band. These objects enable the investigation of the main substructures of the AGN, in particular the core, the jet and its interaction with the…
In this work, we explore constraints on the emergence and longevity of technologically intelligent civilizations in our Galaxy, considering the Fermi paradox. We argue that under optimistic assumptions about the probability of life and…
We present photometric and spectroscopic observations of the members of three previously cataloged compact group (CG) candidates at redshifts z>0.3. These confirm spectroscopic redshifts compatible with being gravitationally bound…
We have obtained deep, multi-band imaging observations around three of the most distant known quasars at redshifts z>6. Standard accretion theory predicts that the supermassive black holes present in these quasars were formed at a very…
We summarize the status of a ``targeted'' redshift survey aimed at establishing the properties of galaxies and their large scale distribution in the redshift range 2.5 < z < 3.5. At the time of this writing, we have obtained spectra of more…
The search for extrasolar Earth-like planets is underway. Over 100 extrasolar giant planets are known to orbit nearby sun-like stars, including several in multiple-planet systems. These planetary systems are stepping stones for the search…
The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10^-7 L_MW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the…
The new generation of IR surveys are revealing and quantifying Galactic features, providing an improved 3-D interpretation of our own Galaxy. We present an analysis of the global distribution of dust clouds in the bulge using the near-IR…
We describe the results of a search for galaxies with large (> 350 km/s) velocity dispersions. The largest systems we have found appear to be the extremes of the early-type galaxy population: compared to other galaxies with similar…
The Galaxy's stellar populations are naturally classified into six `types', of which five have been observed. These are the thin disk (Pop I in the historical scheme), a discrete thick disk (Pop I.5), the metal-rich bulge, which was not…
Pop III stars are the key to the character of primeval galaxies, the first heavy elements, the onset of cosmological reionization, and the seeds of supermassive black holes. Unfortunately, in spite of their increasing sophistication,…