Physical Sciences and Mathematics Commons^™

Supermassive Black Hole Seed Formation At High Redshifts: Long-Term Evolution Of The Direct Collapse, Isaac Shlosman, Jun-Hwan Choi, Mitchell C. Begelman, Kentaro Nagamine

Physics and Astronomy Faculty Publications

We use cosmological adaptive mesh refinement code enzo zoom-in simulations to study the long-term evolution of the collapsing gas within dark matter haloes at z. This direct collapse process is a leading candidate for rapid formation of supermassive black hole (SMBH) seeds. To circumvent the Courant condition at small radii, we apply the sink particle method, focusing on evolution on scales ∼0.01–10 pc. The collapse proceeds in two stages, with the secondary runaway happening within the central 10 pc. The sink particles form when the collapsing gas requires additional refinement of the grid size at the highest refinement level. …

Candels Visual Classifications: Scheme, Data Release, And First Results, Jeyhan S. Kartaltepe, Mark Mozena, Dale D. Kocevski, Daniel H. Mcintosh, Jennifer Lotz, Eric F. Bell, Sandra M. Faber, Harry C. Ferguson, David C. Koo, Robert Bassett, Maksym Bernyk, Kirsten Blancato, Frederic Bournaud, Paolo Cassata, M. Castellano, Edmond Cheung, Christopher J. Conselice, D. Croton, Tomas Dahlen, Duilia F. De Mello, Laura Degroot, Jennifer Donley, Javiera Guedes, Norman A. Grogin, Nimish Hathi, Matt Hilton, Brett Hollon, Anton M. Koekemoer, Nick Liu, Ray A. Lucas

Physics and Astronomy Faculty Publications

We have undertaken an ambitious program to visually classify all galaxies in the five CANDELS fields down to H < 24.5 involving the dedicated efforts of over 65 individual classifiers. Once completed, we expect to have detailed morphological classifications for over 50,000 galaxies spanning 0 < z < 4 over all the fields, with classifications from 3 to 5 independent classifiers for each galaxy. Here, we present our detailed visual classification scheme, which was designed to cover a wide range of CANDELS science goals. This scheme includes the basic Hubble sequence types, but also includes a detailed look at mergers and interactions, the clumpiness of galaxies, k-corrections, and a variety of other structural properties. In this paper, we focus on the first field to be completed—GOODS-S, which has been classified at various depths. The wide area coverage spanning the full field (wide+deep+ERS) includes 7634 galaxies that have been classified by at least three different people. In the deep area of the field, 2534 galaxies have been classified by at least five different people at three different depths. With this paper, we release to the public …

Testing Lorentz Symmetry With Planetary Orbital Dynamics, A. Hees, Q. G. Bailey, C. Le Poncin-Lafitte, A. Bourgoin, A. Rivoldini, B. Lamine, F. Meynadier, C. Guerlin, P. Wolf

Publications

Planetary ephemerides are a very powerful tool to constrain deviations from the theory of general relativity (GR) using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and …

Constraining The Redshift Evolution Of The Cosmic Microwave Background Blackbody Temperature With Plank Data, I. De Martino, R. Génova-Santos, F. Atrio-Barandela, H. Ebeling, A. Kashlinsky, Dale D. Kocevski, C. J. A. P. Martins

Physics and Astronomy Faculty Publications

We constrain the deviation of adiabatic evolution of the universe using the data on the cosmic microwave background (CMB) temperature anisotropies measured by the Planck satellite and a sample of 481 X-ray selected clusters with spectroscopically measured redshifts. To avoid antenna beam effects, we bring all of the maps to the same resolution. We use a CMB template to subtract the cosmological signal while preserving the Thermal Sunyaev–Zeldovich (TSZ) anisotropies; next, we remove galactic foreground emissions around each cluster and we mask out all known point sources. If the CMB blackbody temperature scales with redshift as T(z) …

Supermassive Black Hole Formation At High Redshifts Via Direct Collapse In A Cosmological Context, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman

Physics and Astronomy Faculty Publications

We study the early stage of the formation of seed supermassive black holes via direct collapse in dark matter (DM) haloes, in the cosmological context. We perform high-resolution zoom-in simulations of such collapse at high z. Using the adaptive mesh refinement code enzo, we resolve the formation and growth of a DM halo, until its virial temperature reaches ∼10⁴ K, atomic cooling turns on, and collapse ensues. We demonstrate that direct collapse proceeds in two stages, although they are not well separated. The first stage is triggered by the onset of atomic cooling, and leads to rapidly increasing …

Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen

Honors Scholar Theses

The advent of General Relativity via Einstein's field equations revolutionized our understanding of gravity in our solar system and universe. The idea of General Relativity posits that gravity is entirely due to the geometry of the universe -- that is, the mass distribution throughout the universe results in the "curving" of spacetime, which gives us the physics we see on a large scale. In the framework of General Relativity, we find that the universe behaves differently than was predicted in the model of gravitation developed by Newton. We will derive the general relativistic model for a simple system near a …

Supernatural Cosmic Origins: Challenging The Reigning Paradigm, Rachel Blattner

Senior Honors Theses

Contemporary scientific study primarily uses a paradigm based upon naturalism, materialism, and empiricism on which to base research. The widely accepted cosmological model the big bang theory adheres to this paradigm. Despite many weaknesses in this model and in the paradigm itself, researchers continue to favor the modification of the accepted model over the adoption of other more comprehensive models. The paradigm from which the models proposed by Russell Humphries, John Hartnett, and Jason Lisle come justifies the six-day creation young-earth biblical account and better fits observational evidence with fewer arbitrary assumptions than the paradigm from which the big bang …

Gravitational Wave Background In The Quasi-Steady State Cosmology, Sree Ram Valluri, Sayantan Auddy, J V. Narlikar, S V. Dhurandhar, R G. Vishwakarma

Physics and Astronomy Publications

This paper calculates the expected gravitational wave background (GWB) in the quasi-steady state cosmology (QSSC). The principal sources of gravitational waves in the QSSC are the mini-creation events (MCE). With suitable assumptions the GWB can be computed both numerically and with analytical methods. It is argued that the GWB in QSSC differs from that predicted for the standard cosmology and a future technology of detectors will be able to decide between the two predictions. We also derive a formula for the flux density of a typical extragalactic source of gravitational waves.

Spectroscopic Needs For Imaging Dark Energy Experiments, Jeffrey A. Newman, Alexandra Abate, Filipe B. Abdalla, Sahar Allam, Steven W. Allen, Réza Ansari, Stephen Bailey, Wayne A. Barkhouse, Timothy C. Beers, Michael R. Blanton, Mark Brodwin, Joel R. Brownstein, Robert J. Brunner, Matias Carrasco Kind, Jorge L. Cervantes-Cota, Elliott Cheu, Nora Elisa Chisari, Matthew Colless, Johan Comparat, Jean Coupon, Carlos E. Cunha, Axel De La Macorra, Ian P. Dell'antonio, Brenda L. Frye, Eric J. Gawiser, Neil Gehrels, Kevin Grady, Alex Hagen, Patrick B. Hall, Andrew P. Hearin, Hendrik Hildebrandt, Christopher M. Hirata, Shirley Ho, Klaus Honscheid, Dragan Huterer, Željko Ivezić, Jean-Paul Kneib, Jeffrey W. Kruk, Ofer Lahav, Rachel Mandelbaum, Jennifer L. Marshall, Daniel J. Matthews, Brice Ménard, Ramon Miquel, Marc Moniez, H. W. Moos, John Moustakas, Adam D. Myers, Casey Popovich, John A. Peacock, Changbom Park, Mubdi Rahman, Jason Rhodes, Jean-Stephane Ricol, Iftach Sadeh, Anže Slozar, Samuel J. Schmidt, Daniel K. Stern, J. Anthony Tyson, Anja Von Der Linden, Risa H. Wechsler, W. M. Wood-Vasey, Andrew R. Zentner

Physics Faculty Publications

Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z’s): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z’s will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments.

Hence, to achieve their full potential, imaging-based experiments …

Short-Range Gravity And Lorentz Violation, Quentin G. Bailey, V. Alan Kostelecký, Rui Xu

Publications

Comparatively few searches have been performed for violations of local Lorentz invariance in the pure-gravity sector. We show that tests of short-range gravity are sensitive to a broad class of unconstrained and novel signals that depend on the experimental geometry and on sidereal time.