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Indications of a Late-Time Interaction in the Dark Sector
Melchiorri, Alessandro; Said, Najla; Salvatelli, Valentina +2 more
We show that a general late-time interaction between cold dark matter and vacuum energy is favored by current cosmological data sets. We characterize the strength of the coupling by a dimensionless parameter qV that is free to take different values in four redshift bins from the primordial epoch up to today. This interacting scenario is…
A New Population of Ultra-long Duration Gamma-Ray Bursts
Cenko, S. B.; Covino, S.; Sánchez-Ramírez, R. +38 more
We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalactic transients; in particular, we resolve the long-standing conundrum of the distance of GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z = 0.847 a…
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measuring growth rate and geometry with anisotropic clustering
Aubourg, Éric; Ross, Nicholas P.; Streblyanska, Alina +27 more
We use the observed anisotropic clustering of galaxies in the Baryon Oscillation Spectroscopic Survey Data Release 11 CMASS sample to measure the linear growth rate of structure, the Hubble expansion rate and the comoving distance scale. Our sample covers 8498 deg2 and encloses an effective volume of 6 Gpc3 at an effective re…
Third-epoch Magellanic Cloud Proper Motions. II. The Large Magellanic Cloud Rotation Field in Three Dimensions
van der Marel, Roeland P.; Kallivayalil, Nitya
We present the first detailed assessment of the large-scale rotation of any galaxy based on full three-dimensional velocity measurements. We do this for the LMC by combining our Hubble Space Telescope average proper motion (PM) measurements for stars in 22 fields, with existing line-of-sight (LOS) velocity measurements for 6790 individual stars. W…
Submillimeter Galaxies as Progenitors of Compact Quiescent Galaxies
Berta, S.; Magnelli, B.; Lutz, D. +16 more
Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they forme…
Planck 2013 results. XXX. Cosmic infrared background measurements and implications for star formation
Kneissl, R.; Miville-Deschênes, M. -A.; Boulanger, F. +239 more
We present new measurements of cosmic infrared background (CIB) anisotropies using Planck. Combining HFI data with IRAS, the angular auto- and cross-frequency power spectrum is measured from 143 to 3000 GHz, and the auto-bispectrum from 217 to 545 GHz. The total areas used to compute the CIB power spectrum and bispectrum are about 2240 and 4400 de…
Techniques and Review of Absolute Flux Calibration from the Ultraviolet to the Mid-Infrared
Gordon, Karl D.; Tremblay, P. -E.; Bohlin, Ralph C.
The measurement of precise absolute fluxes for stellar sources has been pursued with increased vigor since the discovery of the dark energy and the realization that its detailed understanding requires accurate spectral energy distributions (SEDs) of redshifted Ia supernovae in the rest frame. The flux distributions of spectrophotometric standard s…
Toward an understanding of foreground emission in the BICEP2 region
Spergel, David N.; Hill, J. Colin; Flauger, Raphael
BICEP2 has reported the detection of a degree-scale B-mode polarization pattern in the Cosmic Microwave Background (CMB) and has interpreted the measurement as evidence for primordial gravitational waves. Motivated by the profound importance of the discovery of gravitational waves from the early Universe, we examine to what extent a combination of…
Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b. I. The Transit
Deming, D.; Crouzet, N.; Madhusudhan, N. +1 more
We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 µm to 1.7 µm and spatially scanned the image across the detector at 2'' s-1. When smoothed to 75 nm bins, the local maxima of the transit depth…
Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
Madhusudhan, Nikku; Burrows, Adam; Fortney, Jonathan J. +13 more
Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orb…