Search Publications
Compensated-current instability of kinetic Alfvén waves
De Keyser, J.; Malovichko, P.; Voitenko, Y.
We study a non-resonant instability of kinetic Alfvén waves (KAWs) driven by compensated currents. Such currents set up in response to energetic ion beams occurring in many space and astrophysical plasmas, like foreshock regions in the solar wind and around supernova remnants. Kinetic effects of the background ion gyroradius make the KAW instabili…
Millimetre polarization of the protoplanetary nebula OH 231.8+4.2: a follow-up study with CARMA
Zijlstra, A. A.; Sabin, L.; Vázquez, R. +4 more
In order to investigate the characteristics and influence of the magnetic field in evolved stars, we performed a follow-up investigation of our previous submillimetre analysis of the protoplanetary nebula (PPN) OH 231.8+4.2, this time at 1.3 mm with the CARMA (Combined Array for Research in Millimeter-wave Astronomy) facility in polarization mode …
Combining physical galaxy models with radio observations to constrain the SFRs of high-z dusty star-forming galaxies
Franceschini, A.; Efstathiou, A.; Silva, L. +2 more
We complement our previous analysis of a sample of z ∼ 1-2 luminous and ultraluminous infrared galaxies [(U)LIRGs], by adding deep Very Large Array radio observations at 1.4 GHz to a large data set from the far-UV to the submillimetre, including Spitzer and Herschel data. Given the relatively small number of (U)LIRGs in our sample with high signal…
Sub-arcsec mid-IR observations of NGC 1614: Nuclear star formation or an intrinsically X-ray weak AGN?
Colina, L.; García-Burillo, S.; Herrero-Illana, R. +10 more
We present new mid-infrared (mid-IR) N-band spectroscopy and Q-band photometry of the local luminous IR galaxy NGC 1614, one of the most extreme nearby starbursts. We analyse the mid-IR properties of the nucleus (central 150 pc) and four regions of the bright circumnuclear (diameter∼600 pc) star-forming (SF) ring of this object. The nucleus differ…
Subaru and Swift observations of V652 Herculis: resolving the photospheric pulsation
Starling, R. L. C.; Jeffery, C. S.; McCormac, J. +4 more
High-resolution spectroscopy with the Subaru High Dispersion Spectrograph, and Swift ultraviolet photometry are presented for the pulsating extreme helium star V652 Her. Swift provides the best relative ultraviolet photometry obtained to date, but shows no direct evidence for a shock at ultraviolet or X-ray wavelengths. Subaru has provided high sp…
Disentangling the outflow and protostars in HH 900 in the Carina Nebula
Anderson, Jay; Smith, Nathan; Bally, John +2 more
HH 900 is a peculiar protostellar outflow emerging from a small, tadpole-shaped globule in the Carina Nebula. Previous Hα imaging with Hubble Space Telescope (HST)/Advanced Camera for Surveys showed an ionized outflow with a wide opening angle that is distinct from the highly collimated structures typically seen in protostellar jets. We present ne…
Cold parsec-scale gas in a zabs ∼ 0.1 sub-damped Lyman α with disparate H2 and 21-cm absorption
Momjian, E.; Muzahid, S.; Srianand, R. +3 more
We present a detailed analysis of a H2-bearing metal-rich sub-damped Lyman α system at zabs = 0.10115 towards the radio-loud quasar J0441-4313, at a projected separation of ∼7.6 kpc from a star-forming galaxy. The H2, {C I}} and {Na I} absorption are much stronger in the redder of the two components seen in the Hub…
Long-term XMM-Newton investigation of two particle-accelerating colliding-wind binaries in NGC 6604: HD 168112 and HD 167971
De Becker, M.
The long-term (over more than one decade) X-ray emission from two massive stellar systems known to be particle accelerators is investigated using XMM-Newton. Their X-ray properties are interpreted taking into account recent information about their multiplicity and orbital parameters. The two targets, HD 168112 and HD 167971, appear to be overlumin…
Line-depth-ratio temperatures for the close binary ν Octantis: new evidence supporting the conjectured circumstellar retrograde planet
Ramm, D. J.
We explore the possibly that either star-spots or pulsations are the cause of a periodic radial velocity (RV) signal (P ∼ 400 d) from the K-giant binary ν Octantis (P ∼ 1050 d, e ∼ 0.25), alternatively conjectured to have a retrograde planet. Our study is based on temperatures derived from 22 line-depth ratios (LDRs) for ν Oct and 20 calibration s…
Corrugated velocity patterns in the spiral galaxies: NGC 278, NGC 1058, NGC 2500 & UGC 3574
Pérez, Enrique; Alfaro, Emilio J.; Sánchez-Gil, M. Carmen
We address the study of the H α vertical velocity field in a sample of four nearly face-on galaxies using long-slit spectroscopy taken with the Intermediate dispersion Spectrograph and Imaging System (ISIS), attached to the William Herschel Telescope (WHT) at the Roque de los Muchachos Observatory (Spain). The spatial structure of the velocity ver…