Search Publications
Can Reconnection be Triggered as a Solar Wind Directional Discontinuity Crosses the Bow Shock? A Case of Asymmetric Reconnection
Gunell, H.; Hamrin, M.; Vaivads, A. +7 more
Here we present some unique observations of reconnection at a quasi-perpendicular bow shock as an interplanetary directional discontinuity (DD) is crossing it simultaneously with the Magnetospheric Multiscale (MMS) mission. There are no burst data, but available data show indications of ongoing reconnection at the shock southward of MMS: a bifurca…
Estimating the mass of CMEs from the analysis of EUV dimmings
Cremades, H.; Balmaceda, L. A.; Nuevo, F. A. +2 more
Context. Reliable estimates of the mass of coronal mass ejections (CMEs) are required to quantify their energy and predict how they affect space weather. When a CME propagates near the observer's line of sight, these tasks involve considerable errors, which motivated us to develop alternative means for estimating the CME mass.
Aims: We aim at…
Using HARPS-N to characterize the long-period planets in the PH-2 and Kepler-103 systems
Vanderburg, Andrew; López-Morales, Mercedes; Buchhave, Lars A. +26 more
We present confirmation of the planetary nature of PH-2b, as well as the first mass estimates for the two planets in the Kepler-103 system. PH-2b and Kepler-103c are both long-period and transiting, a sparsely populated category of exoplanets. We use Kepler light-curve data to estimate a radius, and then use HARPS-N radial velocities to determine …
ULX contribution to stellar feedback: an intermediate-mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4
Östlin, G.; Hayes, M.; Mas-Hesse, J. M. +5 more
Context. X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last <40 Myr and contains some of the most massive super star clusters in the nearby Universe. Given its starburst age and its star-formation rate, ESO 338-4 is one of th…
Gaia-assisted selection of a quasar reddened by dust in an extremely strong damped Lyman-α absorber at z = 2.226
Milvang-Jensen, B.; Fynbo, J. P. U.; Christensen, L. +7 more
Damped Lyman-α absorbers (DLAs) as a class of quasi-stellar object (QSO) absorption-line systems are currently our most important source of detailed information on the cosmic chemical evolution of galaxies. However, the degree to which this information is biased by dust remains to be understood. One strategy is to specifically search for QSOs that…
Constraining the orbit of the planet-hosting binary τ Boötis. Clues about planetary formation and migration
Albrecht, S.; Justesen, A. B.
Context. The formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter τ Boo Ab orbits the primary star in the long-period (P ≳ 1000 yr), highly eccentric (…
X-ray spectra of Sagittarius A East and diffuse X-ray background near the Galactic center
Koyama, Katsuji; Nobukawa, Masayoshi; Uchiyama, Hideki +3 more
This paper reports the analysis procedure and results of simultaneous spectral fits of the Suzaku archive data for Sagittarius (Sgr) A East and the nearby Galactic center X-ray emission (GCXE). The results are that the mixed-morphology supernova remnant Sgr A East has a recombining plasma (RP) with Cr and Mn Heα lines, and a power-law component (P…
Spectroscopic study of the extremely young O-type triple system Herschel 36 A in the Hourglass nebula - I. Orbital properties
Morrell, Nidia I.; Barbá, Rodolfo H.; Maíz Apellániz, Jesús +3 more
We present a detailed spectroscopic study of Herschel 36 A (H36A), the main stellar component of the massive multiple system Herschel 36 in the Hourglass nebula, based on high-resolution optical spectra obtained along an 11 yr span. The three stellar components present in the spectrum of H36A are separated by means of a spectral disentangling tech…
Nearly coeval intermediate-age Milky Way star clusters at very different dynamics evolutionary stages
Piatti, Andrés E.; Dias, Wilton S.; Angelo, Mateus S.
We report astrophysical properties of 12 Milky Way open clusters located beyond a 2 kpc circle around the Sun by using deep optical photometry. We estimated their age and metallicities on the basis of a maximum likelihood approach using astrometric members determined from Gaia DR2 data. The studied clusters turned out to be of intermediate-age (0.…
Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg
Dhillon, V. S.; Gandhi, P.; Marsh, T. R. +6 more
We present a serendipitous multiwavelength campaign of optical photometry simultaneous with Integral X-ray monitoring of the 2015 outburst of the black hole V404 Cyg. Large-amplitude optical variability is generally correlated with X-rays, with lags of order a minute or less compatible with binary light travel time-scales or jet ejections. Rapid o…