Search Publications
The chemodynamics of prograde and retrograde Milky Way stars
Kordopatis, Georges; Recio-Blanco, Alejandra; Hill, Vanessa +1 more
Context. The accretion history of the Milky Way is still unknown, despite the recent discovery of stellar systems that stand out in terms of their energy-angular momentum space, such as Gaia-Enceladus-Sausage. In particular, it is still unclear how these groups are linked and to what extent they are well-mixed.
Aims: We investigate the simila…
Timing Terminators: Forecasting Sunspot Cycle 25 Onset
McIntosh, Scott W.; Leamon, Robert J.; Chapman, Sandra C. +1 more
Recent research has demonstrated the existence of a new type of solar event, the "terminator." Unlike the Sun's signature events, flares and coronal mass ejections, the terminator most likely originates in the solar interior, at or near the tachocline. The terminator signals the end of a magnetic activity cycle at the Sun's equator and the start o…
Kinematic modelling of clusters with Gaia: the death throes of the Hyades
Oh, Semyeong; Evans, Neil Wyn
The precision of the Gaia data offers a unique opportunity to study the internal velocity field of star clusters. We develop and validate a forward-modelling method for the internal motions of stars in a cluster. The model allows an anisotropic velocity dispersion matrix and linear velocity gradient describing rotation and shear, combines radial v…
A wide-area GMRT 610-MHz survey of ELAIS N1 field
Vaccari, M.; Taylor, A. R.; Ishwara-Chandra, C. H. +3 more
In this paper, we present a wide-area 610-MHz survey of the ELAIS N1 field with the GMRT, covering an area of 12.8 deg2 at a resolution of 6 arcsec and with an rms noise of ~40 $\mu$Jy beam-1. This is equivalent to ~20 $\mu$Jy beam-1 rms noise at 1.4 GHz for a spectral index of -0.75. The primary goal of the survey…
The XMM Cluster Survey: new evidence for the 3.5-keV feature in clusters is inconsistent with a dark matter origin
Romer, A. K.; Bhargava, S.; Jeltema, T. +14 more
There have been several reports of a detection of an unexplained excess of X-ray emission at $\simeq$3.5 keV in astrophysical systems. One interpretation of this excess is the decay of sterile neutrino dark matter. The most influential study to date analysed 73 clusters observed by the XMM-Newton satellite. We explore evidence for a ≃3.5-keV exces…
CME-induced Thermodynamic Changes in the Corona as Inferred from Fe XI and Fe XIV Emission Observations during the 2017 August 21 Total Solar Eclipse
Druckmüller, Miloslav; Ding, Adalbert; Boe, Benjamin +3 more
We present the first remote sensing observations of the impact from a Coronal Mass Ejection (CME) on the thermodynamic properties of the solar corona between 1 and 3 R⊙. Measurements of the Fe XI (789.2 nm) and Fe XIV (530.3 nm) emission were acquired with identical narrow-bandpass imagers at three observing sites during the 2017 August…
Regulation of accretion by its outflow in a symbiotic star: the 2016 outflow fast state of MWC 560
Sokoloski, J. L.; Luna, G. J. M.; Munari, U. +11 more
How are accretion discs affected by their outflows? To address this question for white dwarfs accreting from cool giants, we performed optical, radio, X-ray, and ultraviolet observations of the outflow-driving symbiotic star MWC 560 (≡V694 Mon) during its 2016 optical high state. We tracked multi-wavelength changes that signalled an abrupt increas…
Rapid luminosity decline and subsequent reformation of the innermost dust distribution in the changing-look AGN Mrk 590
Minezaki, Takeo; Kokubo, Mitsuru
We examine the long-term optical/near-infrared (NIR) flux variability of a 'changing-look' active galactic nucleus (AGN) Mrk 590 between 1998 and 2007. Multiband multi-epoch optical/NIR photometry data from the SDSS Stripe 82 data base and the Multicolor Active Galactic Nuclei Monitoring (MAGNUM) project reveal that Mrk 590 experienced a sudden lu…
First Observation of a Type II Solar Radio Burst Transitioning between a Stationary and Drifting State
Kontar, Eduard P.; Chrysaphi, Nicolina; Reid, Hamish A. S.
Standing shocks are believed to be responsible for stationary Type II solar radio bursts, whereas drifting Type II bursts are excited by moving shocks often related to coronal mass ejections (CMEs). Observations of either stationary or drifting Type II bursts are common, but a transition between the two states has not yet been reported. Here, we p…
Interplanetary Coronal Mass Ejections as the Driver of Non-recurrent Forbush Decreases
Papaioannou, Athanasios; Belov, Anatoly; Abunina, Maria +5 more
Interplanetary coronal mass ejections (ICMEs) are the counterparts of coronal mass ejections (CMEs) that extend in the interplanetary (IP) space and interact with the underlying solar wind (SW). ICMEs and their corresponding shocks can sweep out galactic cosmic rays (GCRs) and thus modulate their intensity, resulting in non-recurrent Forbush decre…