Craig J. Hogan
A5032945933- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Relativity and Gravitational Theory
- Scientific Research and Discoveries
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Quantum Mechanics and Applications
- Radio Astronomy Observations and Technology
- Noncommutative and Quantum Gravity Theories
- Astrophysics and Star Formation Studies
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Particle physics theoretical and experimental studies
- Computational Physics and Python Applications
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Space Science and Extraterrestrial Life
- Biofield Effects and Biophysics
- Advanced Thermodynamics and Statistical Mechanics
University of Chicago
2015-2024
Fermi National Accelerator Laboratory
2014-2023
The Medical Center of Aurora
2022
Kavli Institute for Particle Astrophysics and Cosmology
2021
University of Michigan–Ann Arbor
2017
Korea Advanced Institute of Science and Technology
2017
University of East Anglia
2013
University of Washington
1999-2008
University of Arizona
1986-2008
Seattle University
1991-2005
We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z 0.62. The luminosity distances these objects are determined by methods that employ relations between SN light curve shape. Combined with previous data from our High-z Supernova Search Team recent results Riess et al., this expanded set 16 high-redshift a 34 nearby used to place constraints on following cosmological parameters: Hubble constant (H0), mass density (ΩM), (i.e.,...
This paper describes the Seventh Data Release of Sloan Digital Sky Survey (SDSS), marking completion original goals SDSS and end phase known as SDSS-II. It includes 11,663 deg2 imaging data, with most ∼2000 increment over previous data release lying in regions low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. survey also repeat on a 120° long, 25 wide stripe along celestial equator Southern Cap, some covered by many 90 individual runs. We...
The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere collect spectra ≈106 galaxies, 100,000 quasars, 30,000 stars, serendipity targets. In 2001 June, SDSS released to general astronomical community its early data release, roughly 462 deg2 including almost 14 million detected objects 54,008 follow-up spectra. were collected in drift-scan mode five bandpasses (u, g, r, i, z); our 95% completeness...
Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z< 0.1), all three seasons (0.05 <z< 0.4), years (0.2 1), it totals 740 spectroscopically confirmed supernovae with high-quality light curves.
The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z=0.3-1.2. These independent observations, confirm result of Riess et al. (1998a) Perlmutter (1999) that supernova luminosity distances imply an accelerating universe. More importantly, they extend range consistently SN Ia to z~1, where signature cosmological effects opposite sign some plausible systematic effects. Consequently, these measurements not only provide another quantitative...
The High-Z Supernova Search is an international collaboration to discover and monitor Type Ia supernovae (SNe Ia) at z > 0.2 with the aim of measuring cosmic deceleration global curvature. Our has pursued a basic understanding in nearby universe, discovering observing large sample objects developing methods measure accurate distances SNe Ia. This paper describes extension this program ≥ 0.2, outlining our search techniques follow-up program. We have devised high-throughput filters that...
This paper describes the Sixth Data Release of Sloan Digital Sky Survey. With this data release, imaging northern Galactic cap is now complete. The survey contains images and parameters roughly 287 million objects over 9583 deg2, including scans a large range latitudes longitudes. also includes 1.27 spectra stars, galaxies, quasars, blank sky (for subtraction) selected 7425 deg2. release much more stellar spectroscopy than was available in previous releases detailed estimates temperatures,...
The Sloan Digital Sky Survey (SDSS) has validated and made publicly available its Second Data Release. This data release consists of 3324 deg2 five-band (ugriz) imaging with photometry for over 88 million unique objects, 367,360 spectra galaxies, quasars, stars, calibrating blank sky patches selected 2627 this area, tables measured parameters from these data. reach a depth r ≈ 22.2 (95% completeness limit point sources) are photometrically astrometrically calibrated to 2% rms 100 mas per...
This paper describes the Fourth Data Release of Sloan Digital Sky Survey (SDSS), including all survey-quality data taken through 2004 June. The release includes five-band photometric for 180 million objects selected over 6670 deg2 and 673,280 spectra galaxies, quasars, stars from 4783 those imaging using standard SDSS target selection algorithms. These numbers represent a roughly 27% increment Third Release; previous releases are included in present release. also an additional 131,840...
We present an estimate of the global budget baryons in all states, with conservative estimates uncertainties, based on relevant information we have been able to marshal. Most today are still form ionized gas, which contributes a mean density uncertain by factor about four. Stars and their remnants relatively minor component, comprising for our best-guess plasma only 17% baryons, while populations contributing most blue starlight comprise less than 5%. The formation galaxies stars within them...
We use Type Ia supernovae studied by the High-z Supernova Search Team to constrain properties of an energy component that may have contributed accelerating cosmic expansion. find for a flat geometry equation-of-state parameter unknown component, αx = Px/ρx, must be less than -0.55 (95% confidence) any value Ωm, and it is further limited < -0.60 if Ωm assumed greater 0.1. These values are inconsistent with being topological defects such as domain walls, strings, or textures. The supernova...
This paper describes the Third Data Release of Sloan Digital Sky Survey (SDSS). release, containing data taken up through 2003 June, includes imaging in five bands over 5282 deg2, photometric and astrometric catalogs 141 million objects detected these data, spectra 528,640 selected 4188 deg2. The pipelines analyzing both images spectroscopy are unchanged from those used our Second Release.
This paper describes the Fifth Data Release (DR5) of Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and represents completion SDSS-I project (whose successor, SDSS-II will continue mid-2008). It five-band photometric for 217 million objects selected over 8000 square degrees, 1,048,960 spectra galaxies, quasars, stars from 5713 degrees that imaging data. These numbers represent a roughly 20% increment those Fourth Release; previous releases are...
We have coordinated Hubble Space Telescope (HST) photometry with ground-based discovery for three supernovae: Type Ia supernovae near z ≈ 0.5 (SN 1997ce, SN 1997cj) and a third event at = 0.97 1997ck). The superb spatial resolution of HST separates each supernova from its host galaxy leads to good precision in the light curves. use these curves relations between luminosity, light-curve shape, color calibrated low-z samples derive relative luminosity distances that are accurate 10% 20% 1....
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. survey region is stripe 2.5° wide centered the celestial equator in Southern Galactic Cap that been imaged numerous times earlier years, enabling construction deep reference image discovery new objects. Supernova observations are being...
Cavitation during a first-order phase transition, which may have occurred in the early Universe as consequence of QCD or electroweak interactions, would produced gravitational radiation two ways: by generating acoustic noise relativistic plasma, and perturbing expansion law on large scales. The author estimates spectrum resulting stochastic background, its dependence parameters governing possibility observing it above instrumental other wave backgrounds local cosmological origin.
The influence of the QCD phase transition on standard cosmological model is examined. Physical mechanisms are analyzed which transport energy and baryon number during from free-quark (unconfined) to hadron (confined) phases matter, with particular attention an effect described by Witten---the concentration baryons in low-entropy bubbles. Two limiting regimes transport, hydrodynamic flow neutrino conduction, discussed their relative importance under various circumstances clarified. spatial...
The diffusion rate of baryons through the big-bang plasma is calculated. Fluctuations in baryon density early Universe lead to inhomogeneities neutron-proton ratio, due differential these particles radiation plasma. For certain types nonlinear fluctuations, some nucleosynthesis would occur very neutron-rich regions. Nuclear products homogeneous neutron-enriched regions are evaluated numerically using a standard reaction network and results used estimate final abundances an inhomogeneous...
Some properties of the world are fixed by physics derived from mathematical symmetries, while others selected an ensemble possibilities. Several successes and failures ``anthropic'' reasoning in this context reviewed light recent developments astrobiology, cosmology, unification physics. Specific issues raised include our space-time location (including reason for present age universe), time scale biological evolution, tuning global cosmological parameters, origin Large Numbers astrophysics...