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Multi-wavelength campaign on NGC 7469. VI. Photoionisation modelling of the emission line regions and the warm absorber
Kriss, G. A.; Arav, N.; Bianchi, S. +16 more
Aims: We aim to investigate and characterise the photoionised X-ray emission line regions within the Seyfert 1 galaxy NGC 7469.
Methods: We applied the photoionisation model, PION, within the spectral fitting code SPEX to analyse the 640 ks reflection grating spectrometer spectrum of NGC 7469 gathered during an XMM-Newton observing campa…
2003-2019 Monitoring of the Crab Emission through INTEGRAL SPI, or Vice Versa
Jourdain, E.; Roques, J. P.
The Crab Nebula is used by many instruments as a calibration source, in particular at high energy, where it is one of the brightest celestial objects. The spectrometer INTEGRAL SPI (20 keV-8 MeV), in operation since 2002 October, offers a large data set dedicated to this source, with regular campaigns planned twice per year. We have analyzed the a…
Evidence for magnetic activity at starbirth: a powerful X-ray flare from the Class 0 protostar HOPS 383
Hamaguchi, Kenji; Kastner, Joel H.; Principe, David A. +1 more
Context. Class 0 protostars represent the earliest evolutionary stage of solar-type stars, during which the majority of the system mass resides in an infalling envelope of gas and dust and is not yet in the central, nascent star. Although X-rays are a key signature of magnetic activity in more evolved protostars and young stars, whether such magne…
The UV Perspective of Low-Mass Star Formation
France, Kevin; Schneider, P. Christian; Günther, H. Moritz
The formation of low-mass (M★≲2M⊙) stars in molecular clouds involves accretion disks and jets, which are of broad astrophysical interest. Accreting stars represent the closest examples of these phenomena. Star and planet formation are also intimately connected, setting the starting point for planetary systems like our own. The ultraviolet (UV) sp…
The Not So Simple Stellar System ω Cen. II. Evidence in Support of a Merging Scenario
Rest, Armin; Mastrobuono-Battisti, Alessandra; Zenteno, Alfredo +7 more
We present multiband photometry covering ∼5° × 5° across ω Cen collected with the Dark Energy Camera on the 4 m Blanco telescope, combined with Hubble Space Telescope and Wide Field Imager data for the central regions. The unprecedented photometric accuracy and field coverage allows us to confirm the different spatial distribution of blue and red …
A SETI survey of the Vela region using the Murchison Widefield Array: Orders of magnitude expansion in search space
Tremblay, C. D.; Tingay, S. J.
Following the results of our previous low-frequency searches for extraterrestrial intelligence (SETI) using the Murchison Widefield Array (MWA), directed towards the Galactic Centre and the Orion Molecular Cloud (Galactic Anticentre), we report a new large-scale survey towards the Vela region with the lowest upper limits thus far obtained with the…
When Does the Onset of Multiple Stellar Populations in Star Clusters Occur? III. No Evidence of Significant Chemical Variations in Main-sequence Stars of NGC 419
Milone, Antonino P.; Li, Chengyuan; Ji, Xin +3 more
Recent studies have revealed that the onset age for the presence of multiple stellar populations (MPs) in star clusters seems to correspond to the disappearance of the extended main-sequence turnoff in young clusters, a pattern associated with stellar rotations. A speculative suggestion is that MPs might be caused by the magnetic brake, a stellar …
Diffuse radio emission in the galaxy cluster SPT-CL J2031-4037: a steep-spectrum intermediate radio halo?
van Weeren, R. J.; Rapetti, David; Intema, H. T. +6 more
The advent of sensitive low-frequency radio observations has revealed a number of diffuse radio objects with peculiar properties that are challenging our understanding of the physics of the intracluster medium. Here, we report the discovery of a steep-spectrum radio halo surrounding the central brightest cluster galaxy (BCG) in the galaxy cluster …
Rotation of Solar Analogs Crossmatching Kepler and Gaia DR2
Barnes, S. A.; Castro, M.; da Costa, J. S. +10 more
A major obstacle to interpreting the rotation period distribution for main-sequence stars from Kepler mission data has been the lack of a precise evolutionary status for these objects. We address this by investigating the evolutionary status based on Gaia Data Release 2 parallaxes and photometry for more than 30,000 Kepler stars with rotation peri…
Correlations of Sunspot Physical Characteristics during Solar Cycle 23
Valio, Adriana; Spagiari, Eduardo; Marengoni, Mauricio +1 more
The behavior of sunspots is governed by the magnetic dynamo acting deep within the convection zone of the Sun. Therefore, knowledge of sunspot physical characteristics and how they evolve in time during a solar cycle can help to improve our understanding of the solar magnetic behavior. This work analyzes the physical characteristics of sunspots du…