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A variable absorption feature in the X-ray spectrum of a magnetar
Mereghetti, Sandro; Esposito, Paolo; Turolla, Roberto +9 more
Soft-γ-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are ma…
A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys
Sanders, D. B.; Taniguchi, Y.; Alexander, D. M. +33 more
We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, Γ, of a power-law energy distribution, over an energy range of 2-10 keV, for X-ray selected, broad-lined radio-quiet…
The Ultra-long Gamma-Ray Burst 111209A: The Collapse of a Blue Supergiant?
Piro, L.; D'Elia, V.; Cutini, S. +8 more
We present optical, X-ray and gamma-ray observations of GRB 111209A, observed at a redshift of z = 0.677. We show that this event was active in its prompt phase for about 25000 s, making it the longest burst ever observed. This rare event could have been detected up to z ~ 1.4 in gamma-rays. Compared to other long gamma-ray bursts (GRBs), GRB 1112…
Dipolarization fronts as a consequence of transient reconnection: In situ evidence
André, M.; Hamrin, M.; Sitnov, M. I. +10 more
Dipolarization fronts (DFs) are frequently detected in the Earth's magnetotail from XGSM = -30 RE to XGSM = -7 RE. How these DFs are formed is still poorly understood. Three possible mechanisms have been suggested in previous simulations: (1) jet braking, (2) transient reconnection, and (3) spontaneous f…
A Correlation between Star Formation Rate and Average Black Hole Accretion in Star-forming Galaxies
Gorjian, Varoujan; Dey, Arjun; Alberts, Stacey +14 more
We present a measurement of the average supermassive black hole accretion rate (BHAR) as a function of the star formation rate (SFR) for galaxies in the redshift range 0.25 < z < 0.8. We study a sample of 1767 far-IR-selected star-forming galaxies in the 9 deg2 Boötes multi-wavelength survey field. The SFR is estimated using 250 &…
The Hinode Spectro-Polarimeter
Kubo, M.; Lites, B. W.; Ichimoto, K. +16 more
The joint Japan/US/UK Hinode mission includes the first large-aperture visible-light solar telescope flown in space. One component of the Focal Plane Package of that telescope is a precision spectro-polarimeter designed to measure full Stokes spectra with the intent of using those spectra to infer the magnetic-field vector at high precision in the…
A Significantly Low CO Abundance toward the TW Hya Protoplanetary Disk: A Path to Active Carbon Chemistry?
Cleeves, L. Ilsedore; Bergin, Edwin A.; Qi, Chunhua +2 more
In this Letter we report the CO abundance relative to H2 derived toward the circumstellar disk of the T-Tauri star TW Hya from the HD (1 - 0) and C18O (2 - 1) emission lines. The HD (1 - 0) line was observed by the Herschel Space Observatory Photodetector Array Camera and Spectrometer whereas C18O (2 - 1) observati…
HerMES: Candidate Gravitationally Lensed Galaxies and Lensing Statistics at Submillimeter Wavelengths
Aussel, H.; Pérez-Fournon, I.; Ivison, R. J. +83 more
We present a list of 13 candidate gravitationally lensed submillimeter galaxies (SMGs) from 95 deg2 of the Herschel Multi-tiered Extragalactic Survey, a surface density of 0.14 ± 0.04 deg-2. The selected sources have 500 µm flux densities (S 500) greater than 100 mJy. Gravitational lensing is confirmed by fol…
Groundwater activity on Mars and implications for a deep biosphere
Michalski, Joseph R.; Niles, Paul B.; Cuadros, Javier +3 more
By the time eukaryotic life or photosynthesis evolved on Earth, the martian surface had become extremely inhospitable, but the subsurface of Mars could potentially have contained a vast microbial biosphere. Crustal fluids may have welled up from the subsurface to alter and cement surface sediments, potentially preserving clues to subsurface habita…
Evidence for Water in the Rocky Debris of a Disrupted Extrasolar Minor Planet
Gänsicke, B. T.; Koester, D.; Farihi, J.
The existence of water in extrasolar planetary systems is of great interest because it constrains the potential for habitable planets and life. We have identified a circumstellar disk that resulted from the destruction of a water-rich and rocky extrasolar minor planet. The parent body formed and evolved around a star somewhat more massive than the…