Search Publications
On the ion-neutral coupling in cometary comae
Eriksson, Anders I.; Vigren, Erik
In a cometary coma, the ion-neutral decoupling distance, sometimes referred to as the ion exobase or collisionopause, can be defined as the cometocentric distance, rin, where ions, initially moving with the neutral outgassing speed, have a probability of 1/e of not colliding with neutrals on their subsequent journey radially outwards. W…
The exceptional X-ray evolution of SN 1996cr in high resolution
Bauer, F. E.; Brandt, W. N.; Quirola-Vásquez, J. +4 more
We present X-ray spectra spanning 18 yr of evolution for SN 1996cr, one of the five nearest SNe detected in the modern era. Chandra HETG exposures in 2000, 2004, and 2009 allow us to resolve spectrally the velocity profiles of Ne, Mg, Si, S, and Fe emission lines and monitor their evolution as tracers of the ejecta-circumstellar medium interaction…
Towards observing reverberating and superefficient pulsar wind nebulae
Coti Zelati, Francesco; Torres, Diego F.; Lin, Tingting
In a recent work, we numerically studied the radiative properties of the reverberation phase of pulsar wind nebulae (PWNe), i.e. when the reverse shock created by the supernova explosion travels back towards the pulsar, compressing the wind bubble. We focused on several well-characterized PWNe and used them as examples for introducing the concept …
Empirical method of proper element calculation and identification of asteroid families
Vinogradova, T. A.
A search for asteroid families was carried out with the use of a proper element set comprising 649 050 asteroid orbits. Proper elements were calculated by the empirical method. This method uses distributions of orbital elements to calculate secular perturbations. There are two types of secular perturbations: the classical perturbations and the Lid…
A cold stellar stream in Pegasus
Perottoni, Hélio D.; Rocha-Pinto, Helio J.; Newberg, Heidi Jo +3 more
We report the serendipitous discovery of a stellar stream in the constellation Pegasus in the south Galactic hemisphere. The stellar stream was detected using the SDSS Data Release 14 by means of a matched filter in the colour-magnitude diagram that is optimized for a stellar population that is 8 Gyr old with [Fe/H] = -0.46 dex, and located at hel…
A low-mass triple system with a wide L/T transition brown dwarf component: NLTT 51469AB/SDSS 2131-0119
Rebolo, R.; Béjar, V. J. S.; Zapatero Osorio, M. R. +6 more
We demonstrate that the previously identified L/T transition brown dwarf SDSS J213154.43-011939.3 (SDSS 2131-0119) is a widely separated (82{^''.}3, ∼3830 au) common proper motion companion to the low-mass star NLTT 51469, which we reveal to be a close binary itself, separated by 0{^''.}64 ± 0{^''.}01 (∼30 au). We …
A radio structure resolved at the deca-parsec scale in the radio-quiet quasar PDS 456 with an extremely powerful X-ray outflow
Zhang, Zhongli; Paragi, Zsolt; Yang, Jun +5 more
Active galactic nuclei (AGNs) accreting at rates close to the Eddington limit can host radiatively driven mildly relativistic outflows. Some of these X-ray absorbing but powerful outflows can produce strong shocks, resulting in a significant non-thermal emission. This outflow-driven radio emission might be detectable in the radio-quiet quasar PDS …
Optical integral field spectroscopy of intermediate redshift infrared bright galaxies
Magdis, G. E.; Farrah, D.; Rigopoulou, D. +10 more
The extreme infrared (IR) luminosity of local luminous and ultraluminous IR galaxies (U/LIRGs; 11 < log L_IR / L_⊙ < 12 and log L_IR / L_⊙ > 12, respectively) is mainly powered by star formation processes triggered by mergers or interactions. While U/LIRGs are rare locally, at z > 1, they become more common, dominate the star formation…
Dynamical masses and mass-to-light ratios of resolved massive star clusters - I. NGC 419 and NGC 1846
Mateo, Mario; Mackey, A. D.; Roederer, Ian U. +4 more
As an introduction of a kinematic survey of Magellanic Cloud (MC) star clusters, we report on the dynamical masses and mass-to-light ratios (M/L) of NGC 419 (Small Magellanic Cloud) and NGC 1846 (Large Magellanic Cloud). We have obtained more than one hundred high-resolution stellar spectra in and around each cluster using the multi-object spectro…
GeV-TeV γ-rays produced by electrons in the kpc-scale jet as a result of Comptonization of the inner jet emission
Bednarek, W.
A few radio galaxies have been discovered to emit GeV-TeV γ-ray emission in spite of the relatively large viewing angles of their jets. We consider a scenario in which such large-angle γ-ray emission is preferentially produced by isotropically distributed relativistic electrons in the kpc-scale jet. These electrons Comptonize soft non-thermal radi…