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Nonlocal gravity and structure in the Universe
Dodelson, Scott; Park, Sohyun
The observed acceleration of the Universe can be explained by modifying general relativity. One such attempt is the nonlocal model of Deser and Woodard. Here we fix the background cosmology using results from the Planck satellite and examine the predictions of nonlocal gravity for the evolution of structure in the Universe, confronting the model w…
Revealing H2D+ Depletion and Compact Structure in Starless and Protostellar Cores with ALMA
Di Francesco, J.; Bourke, T. L.; Caselli, P. +4 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the submillimeter dust continuum and H2D+ 110-111 emission toward two evolved, potentially protostellar cores within the Ophiuchus molecular cloud, Oph A SM1 and SM1N. The data reveal small-scale condensations within both core…
Tracking the CME-driven Shock Wave on 2012 March 5 and Radio Triangulation of Associated Radio Emission
Mierla, M.; Zhukov, A. N.; Magdalenić, J. +5 more
We present a multiwavelength study of the 2012 March 5 solar eruptive event, with an emphasis on the radio triangulation of the associated radio bursts. The main points of the study are reconstruction of the propagation of shock waves driven by coronal mass ejections (CMEs) using radio observations and finding the relative positions of the CME, th…
Coupled dark energy with perturbed Hubble expansion rate
Yang, Weiqiang; Xu, Lixin
The coupling between dark sectors provides a possible approach to mitigate the coincidence problem of the cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with dark matter is proportional the Hubble parameter and energy density of dark energy, that is, Q ¯ =3 ξx
On the connection between the intergalactic medium and galaxies: the H I-galaxy cross-correlation at z ≲ 1
Tejos, Nicolas; Bechtold, Jill; Davé, Romeel +9 more
We present a new optical spectroscopic survey of 1777 `star-forming' (`SF') and 366 `non-star-forming' (`non-SF') galaxies at redshifts z ∼ 0-1 (2143 in total), 22 AGN and 423 stars, observed by instruments such as the Deep Imaging Multi-Object Spectrograph, the Visible Multi-Object Spectrograph and the Gemini Multi-Object Spectrograph, in three f…
The Atacama Cosmology Telescope: dusty star-forming galaxies and active galactic nuclei in the Southern survey
Hilton, Matt; Bond, J. Richard; Crichton, Devin +28 more
We present a catalogue of 191 extragalactic sources detected by the Atacama Cosmology Telescope (ACT) at 148 and/or 218 GHz in the 2008 Southern survey. Flux densities span 14 -1700 mJy, and we use source spectral indices derived using ACT-only data to divide our sources into two subpopulations: 167 radio galaxies powered by central active galacti…
On the origin of pressure and magnetic perturbations ahead of dipolarization fronts
Runov, A.; Angelopoulos, V.; Zhou, Xu-Zhi +2 more
Dipolarization fronts (DFs), earthward-propagating structures in the Earth's magnetotail current sheet with sharp enhancements of the northward magnetic field Bz, are typically preceded by minor decreases in Bz. Other characteristic DF precursor signatures, including earthward flows and plasma density/pressure enhancements, h…
Simulating the Formation of a Sigmoidal Flux Rope in AR10977 from SOHO/MDI Magnetograms
Green, L. M.; Gibb, G. P. S.; Mackay, D. H. +1 more
The modeling technique of Mackay et al. is applied to simulate the coronal magnetic field of NOAA active region AR10977 over a seven day period (2007 December 2-10). The simulation is driven with a sequence of line-of-sight component magnetograms from SOHO/MDI and evolves the coronal magnetic field though a continuous series of non-linear force-fr…
The first Frontier Fields cluster: 4.5 µm excess in a z ~ 8 galaxy candidate in Abell 2744
Kneib, J. -P.; Pérez-Fournon, I.; Schaerer, D. +10 more
Aims: We present in this letter the first analysis of a z ~ 8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744 as part of the Hubble Frontier Fields legacy program.
Methods: We applied the most commonly used methods to select exceptionally high-redshift galaxies by combining non-detection and color criteria usi…
NuSTAR Observations of Heavily Obscured Quasars at z ~ 0.5
Harrison, F. A.; Stern, D.; Zhang, W. W. +23 more
We present NuSTAR hard X-ray observations of three Type 2 quasars at z ≈ 0.4-0.5, optically selected from the Sloan Digital Sky Survey. Although the quasars show evidence for being heavily obscured, Compton-thick systems on the basis of the 2-10 keV to [O III] luminosity ratio and multiwavelength diagnostics, their X-ray absorbing column densities…