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Two γ-ray bursts from dusty regions with little molecular gas
Kohno, K.; Nakanishi, K.; Tamura, Y. +4 more
Long-duration γ-ray bursts are associated with the explosions of massive stars and are accordingly expected to reside in star-forming regions with molecular gas (the fuel for star formation). Previous searches for carbon monoxide (CO), a tracer of molecular gas, in burst host galaxies did not detect any emission. Molecules have been detected as ab…
Discovery of the Hard Spectrum VHE γ-Ray Source HESS J1641-463
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +229 more
This Letter reports the discovery of a remarkably hard spectrum source, HESS J1641-463, by the High Energy Stereoscopic System (H.E.S.S.) in the very high energy (VHE) domain. HESS J1641-463 remained unnoticed by the usual analysis techniques due to confusion with the bright nearby source HESS J1640-465. It emerged at a significance level of 8.5 s…
Gauribidanur Low-Frequency Solar Spectrograph
Ramesh, R.; Kathiravan, C.; Kishore, P. +2 more
A new radio spectrograph, dedicated to observe the Sun, has been recently commissioned by the Indian Institute of Astrophysics (IIA) at the Gauribidanur Radio Observatory, about 100 km North of Bangalore. The instrument, called the Gauribidanur Low-frequency Solar Spectrograph (GLOSS), operates in the frequency range≈40 - 440 MHz. Radio emission i…
Unusual Water Production Activity of Comet C/2012 S1 (ISON): Outbursts and Continuous Fragmentation
Bertaux, J. -L.; Combi, M. R.; Fougere, N. +3 more
The Solar Wind ANisotropies (SWAN) all-sky hydrogen Lyα camera on the SOlar and Heliospheric Observer (SOHO) satellite observed the hydrogen coma of comet C/2012 S1 (ISON) for most of the last month of its activity from 2013 October 24 to November 24, ending just 4 days before perihelion and its final disruption. The water production rate of the c…
Testing quantum gravity effects with latest CMB observations
Wang, Yi; Cai, Yi-Fu
Inspired by quantum gravitational physics, the approach of non-commutative (NC) phase space leads to a modified dispersion relation of gravitational waves. This feature, if applied to the very early universe, gives rise to a modified power spectrum of primordial tensor perturbations with a suppression of power on large scales. We confront this phe…
z ~ 1 Lyα Emitters. I. The Luminosity Function
Cowie, Lennox L.; Barger, Amy J.; Wold, Isak G. B.
We construct a flux-limited sample of 135 candidate z ~ 1 Lyα emitters (LAEs) from Galaxy Evolution Explorer (GALEX) grism data using a new data cube search method. These LAEs have luminosities comparable to those at high redshifts and lie within a 7 Gyr gap present in existing LAE samples. We use archival and newly obtained optical spectra to ver…
Mapping the wavelength position of deepest absorption features to explore mineral diversity in hyperspectral images
van Ruitenbeek, Frank J. A.; Bakker, Wim H.; van der Werff, Harald M. A. +5 more
A new method is presented for the exploratory analysis of hyperspectral OMEGA imagery of Mars. It involves mapping the wavelength position and depth of the deepest absorption feature in the range between 2.1 and 2.4 µm, where reflectance spectra of minerals such as phyllosilicates, carbonates and sulphates contain diagnostic absorption featu…
The violent youth of bright and massive cluster galaxies and their maturation over 7 billion years
Kocevski, D. D.; Lemaux, B. C.; Ascaso, B. +4 more
In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ∼ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ∼ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented…
Outflow Structure of the Quiet Sun Corona Probed by Spacecraft Radio Scintillations in Strong Scattering
Pätzold, Martin; Imamura, Takeshi; Ando, Hiroki +11 more
Radio scintillation observations have been unable to probe flow speeds in the low corona where the scattering of radio waves is exceedingly strong. Here we estimate outflow speeds continuously from the vicinity of the Sun to the outer corona (heliocentric distances of 1.5-20.5 solar radii) by applying the strong scattering theory to radio scintill…
Improved Hubble Space Telescope proper motions for Tycho-G and other stars in the remnant of Tycho's Supernova 1572
Filippenko, A. V.; Ruiz-Lapuente, P.; Bedin, L. R. +3 more
With archival and new Hubble Space Telescope observations, we have refined the space-velocity measurements of the stars in the central region of the remnant of Tycho's supernova (SN) 1572, one of the historical Galactic Type Ia supernova remnants (SNRs). We derived a proper motion for Tycho-G of (µαcos δ; µδ)…