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Ionization toward the high-mass star-forming region NGC 6334 I
Ceccarelli, Cecilia; Lis, Dariusz C.; Olmi, Luca +3 more
Context. Ionization plays a central role in the gas-phase chemistry of molecular clouds. Since ions are coupled with magnetic fields, which can in turn counteract gravitational collapse, it is of paramount importance to measure their abundance in star-forming regions.
Aims: We use spectral line observations of the high-mass star-forming regio…
Anomalous flows in a sunspot penumbra
Venkatakrishnan, P.; Mathew, Shibu K.; Louis, Rohan E. +1 more
Context. The photospheric Evershed flow is a distinct characteristic of penumbrae that is closely associated with the photometric and magnetic structure of sunspots.
Aims: We analyse the properties of an anomalous flow in the photosphere in a sunspot penumbra and compare it with those of the regular Evershed flow.
Methods: High-resolutio…
Cosmic-Ray Modulation: an Ab Initio Approach
Burger, R. A.; Engelbrecht, N. E.
A better understanding of cosmic-ray modulation in the heliosphere can only be gained through a proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays. We present an ab initio model for cosmic-ray modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. Thi…
XMM-Newton Observations of Young and Energetic Pulsar J2022+3842
Pavlov, G. G.; Kargaltsev, O.; Arumugasamy, P.
We report on XMM-Newton EPIC observations of the young pulsar J2022+3842, with a characteristic age of 8.9 kyr. We detected X-ray pulsations and found the pulsation period P ≈ 48.6 ms, and its derivative \dot{P}\approx 8.6\times 10^{-14}, which is two times larger than previously reported values. The pulsar exhibits two very narrow (FWHM ~1.2 ms) …
SCoPE: an efficient method of Cosmological Parameter Estimation
Das, Santanu; Souradeep, Tarun
Markov Chain Monte Carlo (MCMC) sampler is widely used for cosmological parameter estimation from CMB and other data. However, due to the intrinsic serial nature of the MCMC sampler, convergence is often very slow. Here we present a fast and independently written Monte Carlo method for cosmological parameter estimation named as Slick Cosmological …
Star Formation Rate and Extinction in Faint z ~ 4 Lyman Break Galaxies
Owen, Frazer N.; Wang, Wei-Hao; To, Chun-Hao
We present a statistical detection of 1.5 GHz radio continuum emission from a sample of faint z ~ 4 Lyman break galaxies (LBGs). To constrain their extinction and intrinsic star formation rate (SFR), we combine the latest ultradeep Very Large Array 1.5 GHz radio image and the Hubble Space Telescope Advanced Camera for Surveys (ACS) optical images …
Dust formation by failed supernovae
Kochanek, C. S.
We consider dust formation during the ejection of the hydrogen envelope of a red supergiant during a failed supernova (SN) creating a black hole. While the dense, slow moving ejecta are very efficient at forming dust, only the very last phases of the predicted visual transient will be obscured. The net grain production consists of Md ∼ …
Binary white dwarfs in the halo of the Milky Way
Toonen, Silvia; Brown, Anthony G. A.; Helmi, Amina +4 more
Aims: We study single and binary white dwarfs in the inner halo of the Milky Way in order to learn more about the conditions under which the population of halo stars was born, such as the initial mass function (IMF), the star formation history, or the binary fraction.
Methods: We simulate the evolution of low-metallicity halo stars at di…
A partial eclipse of the heart: the absorbed X-ray low state in Mrk 1048
Schartel, N.; Santos-Lleó, M.; Fabian, A. C. +4 more
We present two new XMM-Newton observations of an unprecedented low-flux state in the Seyfert 1 Mrk 1048 (NGC 985), taken in 2013. The X-ray flux below 1 keV drops by a factor of 4-5, whereas the spectrum above 5 keV is essentially unchanged. This points towards an absorption origin for the low state, and we confirm this with spectral fitting, find…
The Herschel Fornax Cluster Survey II: FIR properties of optically selected Fornax cluster galaxies
Bianchi, S.; De Looze, I.; Auld, R. +13 more
The Herschel Fornax Cluster Survey is a deep, far-infrared (FIR) survey of the Fornax cluster. The survey is in five Herschel bands (100-500 µm) and covers an area of 16 deg2 centred on NGC 1399. This paper presents photometry, detection rates, dust masses, and temperatures using an optically selected sample from the Fornax Cluste…