Monthly Notices of the Royal Astronomical Society

http://mnras.oxfordjournals.org

List of Papers (Total 33,854)

The deep OB star population in Carina from the VST Photometric Hα Survey (VPHAS+)

Massive OB stars are critical to the ecology of galaxies and yet our knowledge of OB stars in the Milky Way, fainter than V ∼ 12, remains patchy. Data from the VST Photometric Hα Survey (VPHAS+) permit the construction of the first deep catalogues of blue excess-selected OB stars, without neglecting the stellar field. A total of 14 900 candidates with 2MASS cross-matches are blue...

Universe opacity and EBL

The observed extragalactic background light (EBL) is affected by light attenuation due to absorption of light by galactic and intergalactic dust in the Universe. Even galactic opacity of 10–20 per cent and minute universe intergalactic opacity of 0.01 mag h Gpc−1 at the local Universe have a significant impact on the EBL because obscuration of galaxies and density of...

KiDS-450: cosmological parameter constraints from tomographic weak gravitational lensing

We present cosmological parameter constraints from a tomographic weak gravitational lensing analysis of ∼450 deg2 of imaging data from the Kilo Degree Survey (KiDS). For a flat Λ cold dark matter (ΛCDM) cosmology with a prior on H0 that encompasses the most recent direct measurements, we find $S_8\equiv \sigma _8\sqrt{\Omega _{\rm m}/0.3}=0.745\pm 0.039$. This result is in good...

GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey – I. A low-frequency extragalactic catalogue

Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalogue, utilizing the first year of observations. The catalogue covers 24 831 square degrees, over declinations south of +30° and Galactic...

A LOFAR mini-survey for low-frequency radio emission from the nearest brown dwarfs

We have conducted a mini-survey for low-frequency radio emission from some of the closest brown dwarfs to the Sun with rapid rotation rates: SIMP J013656.5+093347, WISEPC J150649.97+702736.0 and WISEPA J174124.26+255319.5. We have placed robust 3σ upper limits on the flux density in the 111–169 MHz frequency range for these targets: WISE 1506: <0.72 mJy; WISE 1741: <0.87 mJy...

On the resonant detonation of sub-Chandrasekhar mass white dwarfs during binary inspiral

White dwarfs (WDs) are believed to detonate via explosive Carbon-fusion in a Type Ia supernova (SN) when their temperature and/or density reach the point where Carbon is ignited in a runaway reaction. Observations of the Type Ia SN rate imply that all WD binaries that merge through the emission of gravitational radiation within a Hubble time should result in SNe, regardless of...

A PSF-based approach to Kepler/K2 data – II. Exoplanet candidates in Praesepe (M 44)★

In this work, we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a point-spread function (PSF)-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on...

About AGN ionization echoes, thermal echoes and ionization deficits in low-redshift Lyα blobs

We report the discovery of 14 Lyα blobs (LABs) at z ∼ 0.3, existing at least 4–7 billion years later in the Universe than all other LABs known. Their optical diameters are 20–70 kpc, and GALEX data imply Lyα luminosities of (0.4–6.3) × 1043 erg s−1. Contrary to high-z LABs, they live in low-density areas. They are ionized by AGN, suggesting that cold accretion streams as a power...

Inference of magnetic field in the coronal streamer invoking kink wave motions generated by multiple EUV waves

We analyse the observations from Solar TErrestrial RElations Observatory (STEREO) of an oscillating coronal streamer. STEREO-B Extreme Ultraviolet Imaging (EUVI) temporal data on 2012 March 7 show an evolution of two consecutive EUV waves that interact with footpoint of a coronal streamer clearly evident in the co-spatial and co-temporal STEREO-B/COR-1 observations. The waves are...

Modelling the evolution of a comet subsurface: implications for 67P/Churyumov–Gerasimenko

Modelling the evolution of comets is a complex task aiming at providing constraints on physical processes and internal properties that are inaccessible to observations, although they could potentially bring key elements to our understanding of the origins of these primitive objects. This field has made a tremendous step forward in the post-Giotto area, owing to detailed space...

The perihelion activity of comet 67P/Churyumov–Gerasimenko as seen by robotic telescopes

Around the time of its perihelion passage, the observability of 67P/Churyumov–Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where service/queue-scheduled mode was...

Comet 67P/Churyumov–Gerasimenko preserved the pebbles that formed planetesimals

Solar system formation models predict that the building blocks of planetesimals were mm- to cm-sized pebbles, aggregates of ices and non-volatile materials, consistent with the compact particles ejected by comet 67P/Churyumov–Gerasimenko (67P hereafter) and detected by GIADA (Grain Impact Analyzer and Dust Accumulator) on-board the Rosetta spacecraft. Planetesimals were formed by...

Ortho-to-para abundance ratios of NH2 in 26 comets: implications for the real meaning of OPRs

Abundance ratios of nuclear-spin isomers for cometary molecules having identical protons, such as water and ammonia, have been measured and discussed from the viewpoint that they are primordial characters in comet. In the case of ammonia, its ortho-to-para abundance ratio (OPR) is usually estimated from OPRs of NH2 because of difficulty in measuring OPR of ammonia directly. We...

2D photochemical model for forbidden oxygen line emission for comet 1P/Halley

We present here a 2D model of photochemistry for computing the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines at 577.7, 630, and 636.4 nm, in case of the comet 1P/Halley. The presence of O2 within cometary atmospheres, measured by the in situ Rosetta and Giotto missions, necessitates a revision of the usual photochemical...

A primordial origin for molecular oxygen in comets: a chemical kinetics study of the formation and survival of O2 ice from clouds to discs

Molecular oxygen has been confirmed as the fourth most abundant molecule in cometary material (O2/H2O ∼ 4 per cent) and is thought to have a primordial nature, i.e. coming from the interstellar cloud from which our Solar system was formed. However, interstellar O2 gas is notoriously difficult to detect and has only been observed in one potential precursor of a solar-like system...

A porosity gradient in 67P/C-G nucleus suggested from CONSERT and SESAME-PP results: an interpretation based on new laboratory permittivity measurements of porous icy analogues

The Rosetta spacecraft made a rendezvous with comet 67P/Churyumov-Gerasimenko (67P) in 2014 August, soon after the Philae module landed on the small lobe of the nucleus on 2014 November 12. The CONSERT instrument, onboard Rosetta and Philae, sounded the upper part of the interior of 67P with radiowaves at 90 MHz and determined an average of the real part of the permittivity...