Search Publications
Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS
Srivastava, A. K.; Murawski, K.; Dwivedi, B. N. +2 more
We investigate the Interface Region Imaging Spectrograph (IRIS) observations of the quiet-Sun (QS) to understand the propagation of acoustic waves in transition region (TR) from photosphere. We selected a few IRIS spectral lines, which include the photospheric (Mn I 2801.25 Å), chromospheric (Mg II k 2796.35 Å), and TR (C II 1334.53 Å), to investi…
Tracking of an electron beam through the solar corona with LOFAR
Strassmeier, K. G.; McKean, J. P.; Eislöffel, J. +88 more
The Sun's activity leads to bursts of radio emission, among other phenomena. An example is type-III radio bursts. They occur frequently and appear as short-lived structures rapidly drifting from high to low frequencies in dynamic radio spectra. They are usually interpreted as signatures of beams of energetic electrons propagating along coronal mag…
The CARMENES search for exoplanets around M dwarfs. The warm super-Earths in twin orbits around the mid-type M dwarfs Ross 1020 (GJ 3779) and LP 819-052 (GJ 1265)
Schmitt, J. H. M. M.; Amado, P. J.; Caballero, J. A. +27 more
We announce the discovery of two planetary companions orbiting around the low-mass stars Ross 1020 (GJ 3779, M4.0V) and LP 819-052 (GJ 1265, M4.5V). The discovery is based on the analysis of CARMENES radial velocity (RV) observations in the visual channel as part of its survey for exoplanets around M dwarfs. In the case of GJ 1265, CARMENES observ…
The discovery of a five-image lensed quasar at z = 3.34 using PanSTARRS1 and Gaia
McMahon, Richard G.; Fassnacht, Christopher D.; Auger, Matthew W. +8 more
We report the discovery, spectroscopic confirmation and mass modelling of the gravitationally lensed quasar system PS J0630-1201. The lens was discovered by matching a photometric quasar catalogue compiled from Pan-STARRS1 and Wide-field Infrared Survey Explorer photometry to the Gaia data release 1 catalogue, exploiting the high spatial resolutio…
Electromagnetic Electron Cyclotron Instability in the Solar Wind
Lazar, M.; Yoon, P. H.; López, R. A. +1 more
The abundant reports on the existence of electromagnetic high-frequency fluctuations in space plasmas have increased the expectations that theoretical modeling may help understand their origins and implications (e.g., kinetic instabilities and dissipation). This paper presents an extended quasi-linear approach of the electromagnetic electron cyclo…
On the Impact of Helium Content on the RR Lyrae Distance Scale
Marconi, M.; Castellani, M.; Bono, G. +3 more
We constructed new sets of He-enhanced (Y = 0.30, Y = 0.40) nonlinear, time-dependent convective hydrodynamical models of RR Lyrae (RRL) stars covering a broad range in metal abundances (Z = 0.0001-0.02). The increase in He content from the canonical value (Y = 0.245) to Y = 0.30-0.40 causes a simultaneous increase in stellar luminosity and in pul…
Temperature constraints from inversions of synthetic solar optical, UV, and radio spectra
Leenaarts, J.; da Silva Santos, J. M.; de la Cruz Rodríguez, J.
Context. High-resolution observations of the solar chromosphere at millimeter wavelengths are now possible with the Atacama Large Millimeter Array (ALMA), bringing with them the promise of tackling many open problems in solar physics. Observations from other ground and space-based telescopes will greatly benefit from coordinated endeavors with ALM…
Late-time Flattening of Type Ia Supernova Light Curves: Constraints from SN 2014J in M82
Baade, Dietrich; Sparks, William B.; Wang, Lifan +11 more
The very nearby Type Ia supernova 2014J in M82 offers a rare opportunity to study the physics of thermonuclear supernovae at extremely late phases (≳800 days). Using the Hubble Space Telescope, we obtained 6 epochs of high-precision photometry for SN 2014J from 277 days to 1181 days past the B-band maximum light. The reprocessing of electrons and …
Dancing Twins: Stellar Hierarchies That Formed Sequentially?
Tokovinin, Andrei
This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer co…
COS-Weak: probing the CGM using analogues of weak Mg II absorbers at z < 0.3
Narayanan, A.; Muzahid, S.; Charlton, J. +5 more
We present a sample of 34 weak metal line absorbers at z < 0.3 selected by the simultaneous >3σ detections of the Si IIλ1260 and C IIλ1334 absorption lines, with Wr(Si II)<0.2 Å and Wr(C II)<0.3 Å, in archival HST/COS spectra. Our sample increases the number of known low-z `weak absorbers' by a factor of >5. Th…