Search Publications
The surface magnetic activity of the weak-line T Tauri stars TWA 7 and TWA 25
Donati, J. -F.; Wright, D.; Folsom, C. P. +5 more
We present an analysis of spectropolarimetric observations of the low-mass weak-line T Tauri stars TWA 25 and TWA 7. The large-scale surface magnetic fields have been reconstructed for both stars using the technique of Zeeman Doppler imaging. Our surface maps reveal predominantly toroidal and non-axisymmetric fields for both stars. These maps rein…
Direct geometrical measurement of the Hubble constant from galaxy parallax: predictions for the Vera C. Rubin Observatory and Nancy Grace Roman Space Telescope
Croft, Rupert A. C.
We investigate the possibility that a statistical detection of the galaxy parallax shifts due to the Earth's motion with respect to the cosmic microwave background frame (cosmic secular parallax) could be made by the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) or by the Nancy Grace Roman Space Telescope (NGRST), and used to me…
Properties of a hypothetical cold pulsar wind in LS 5039
Bosch-Ramon, V.
Context. LS 5039 is a powerful high-mass gamma-ray binary that probably hosts a young non-accreting pulsar. However, despite the wealth of data available, the means by which the non-thermal emitter is powered are still unknown.
Aims: We use a dynamical-radiative numerical model, and multiwavelength data, to constrain the properties of a hypot…
NGC 1605a and NGC 1605b: An Old Binary Open Cluster in the Galaxy
Camargo, Denilso
This work communicates the discovery of a binary open cluster within the Galaxy. NGC 1605 presents an unusual morphology with a sparse stellar distribution and a double core in close angular proximity. The 2MASS and Gaia-EDR3 field-star decontaminated color-magnitude diagrams (CMDs) show two distinct stellar populations located at the same helioce…
Revised Surface Abundances of R Coronae Borealis Stars
Reddy, Arumalla B. S.; Pandey, Gajendra; Hema, B. P.
Surface abundances of 14 (11 majority class and three minority class) R Coronae Borealis stars (RCBs) along with the final-flash object, V4334 Sgr (Sakurai's object) are revised based on their carbon abundances measured from the observed C2 bands; note that the earlier reported abundances were derived using an assumed carbon abundance d…
Relativistic Reflection in NGC 4151
Zdziarski, Andrzej A.; Szanecki, Michał; Niedźwiecki, Andrzej
We investigate the X-ray spectrum of the Seyfert galaxy NGC 4151 using the simultaneous Suzaku/NuSTAR observation and flux-resolved INTEGRAL spectra supplemented by Suzaku and XMM observations. Our best spectral solution indicates that the narrow Fe Kα line is produced in Compton-thin matter at a distance of several hundred gravitational radii. In…
The five axes of the Turtle: symmetry and asymmetry in NGC 6210
López, J. A.; Henney, William J.; García-Díaz, Ma T. +1 more
We carry out a comprehensive kinematic and morphological study of the asymmetrical planetary nebula: NGC 6210, known as the Turtle. The nebula's spectacularly chaotic appearance has led to proposals that it was shaped by mass transfer in a triple star system. We study the three-dimensional structure and kinematics of its shells, lobes, knots, and …
INTEGRAL discovery of a high-energy tail in the microquasar Cygnus X-3
Rodriguez, J.; Wilms, J.; Laurent, P. +3 more
Context. The X-ray spectra of X-ray binaries are dominated by emission of either soft or hard X-rays which defines their soft and hard spectral states. While the generic picture is relatively well understood, little is known about the interplay of the various media at work, or about the reasons why some sources do not follow common behavior. Cygnu…
A Possible Kilonova Powered by Magnetic Wind from a Newborn Black Hole
Liu, Yu; Zhang, Bin-Bin; Lü, Hou-Jun +4 more
The merger of binary neutron stars (NS-NS) as the progenitor of short gamma-ray bursts (GRBs) has been confirmed by the discovery of the association of the gravitational-wave (GW) event GW170817 with GRB 170817A. However, the merger product of binary NS remains an open question. An X-ray plateau followed by a steep decay ("internal plateau") has b…
Broadened profiles of diffuse interstellar bands
Krełowski, J.; Galazutdinov, G. A.; Siebenmorgen, R. +3 more
The paper describes profile broadening and peak wavelength variation of diffuse interstellar bands (DIBs) measured for 46 lines of sight, probably caused by the physical properties of intervening clouds. The full width at half-maximum of four studied DIBs (5780, 5797, 6196 and 6614 Å) demonstrates strong variability, sometimes doubling the widths …