Search Publications
Searching for stellar flares from low-mass stars using ASKAP and TESS
Ramsay, Gavin; Gallagher, Peter T.; Kaplan, David L. +7 more
Solar radio emission at low frequencies (<1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of activity than previously thought. Observations of active M dwarfs at low frequencies can provide informat…
Cycle dependence of a quasi-biennial variability in the solar interior
Broomhall, A. -M.; Jain, K.; Tripathy, S. C. +3 more
We investigated the solar cycle dependence on the presence and periodicity of the Quasi-Biennial Oscillation (QBO). Using helioseismic techniques, we used solar oscillation frequencies from the Global Oscillations Network Group (GONG), Michelson Doppler Imager (MDI), and Helioseismic and Magnetic Imager (HMI) in the intermediate-degree range to in…
X-ray intraday variability and power spectral density profiles of the blazar 3C 273 with XMM-Newton during 2000-2021
Gupta, Alok C.; Wiita, Paul J.; Ward, Martin +3 more
We present X-ray intraday variability and power spectral density (PSD) analyses of the longest 23 pointed XMM-Newton observations of the blazar 3C 273 that were taken during 2000-2021. These good time intervals contain between 5 and 24.6 h of data. Variability has been estimated in three energy bands: 0.2-2 keV (soft), 2-10 keV (hard), and 0.2-10 …
ULX pulsar Swift J0243.6+6124 observations with NuSTAR: dominance of reflected emission in the super-Eddington state
Gilfanov, M. R.; Tsygankov, S. S.; Filippova, E. V. +1 more
We report the discovery of the bright reflected emission component in the super-Eddington state of the ultraluminous X-ray pulsar Swift J0243.6+6124, based on the NuSTAR observations of the source during its 2017 outburst. The flux of the reflected emission is weakly variable over the pulsar phase while the direct emission shows significantly larg…
Zodiacal exoplanets in time (ZEIT) XII: a directly imaged planetary-mass companion to a young Taurus M dwarf star
Kuzuhara, M.; Tamura, M.; Kudo, T. +21 more
We report the discovery of a resolved (0.9 arcsec) substellar companion to a member of the 1-5 Myr Taurus star-forming region. The host star (2M0437) is a single mid-M type (Teff ≈ 3100 K) dwarf with a position, space motion, and colour-magnitude that support Taurus membership, and possible affiliation with a ~2.5-Myr-old subgroup. A co…
Unveiling the disc structure in ultraluminous X-ray source NGC 55 ULX-1
Fabian, A. C.; Pinto, C.; Di Salvo, T. +11 more
Ultraluminous X-ray sources (ULXs) are the most extreme among X-ray binaries in which the compact object, a neutron star or a black hole, accretes matter from the companion star, and exceeds a luminosity of $10^{39} \ \rm erg \, s^{-1}$ in the X-ray energy band alone. Despite two decades of studies, it is still not clear whether ULX spectral trans…
A triple star origin for T Pyx and other short-period recurrent novae
Knigge, C.; Toonen, S.; Boekholt, T. C. N.
Recurrent novae are star systems in which a massive white dwarf accretes material at such a high rate that it undergoes thermonuclear runaways every 1-100 yr. They are the only class of novae in which the white dwarf can grow in mass, making some of these systems strong Type Ia supernova progenitor candidates. Almost all known recurrent novae are …
Generalized model-independent characterization of strong gravitational lenses VIII. Automated multiband feature detection to constrain local lens properties
Griffiths, Richard E.; Wagner, Jenny; Lin, Joyce
As established in previous papers of this series, observables in highly distorted and magnified multiple images caused by the strong gravitational lensing effect can be used to constrain the distorting properties of the gravitational lens at the image positions. If the background source is extended and contains substructure, like star forming regi…
S-PLUS: exploring wide field properties of multiple populations in galactic globular clusters at different metallicities
Chies-Santos, Ana L.; Mendes de Oliveira, Claudia; Bastian, Nate +9 more
Multiple stellar populations (MSPs) are a ubiquitous phenomenon in Galactic globular clusters (GCs). By probing different spectral ranges affected by different absorption lines using the multiband photometric survey S-PLUS, we study four GCs - NGC 104, NGC 288, NGC 3201, and NGC 7089 - that span a wide range of metallicities. With the combination …
Impact of point spread function higher moments error on weak gravitational lensing
Mandelbaum, Rachel; LSST Dark Energy Science Collaboration; Zhang, Tianqing
Weak gravitational lensing is one of the most powerful tools for cosmology, while subject to challenges in quantifying subtle systematic biases. The point spread function (PSF) can cause biases in weak lensing shear inference when the PSF model does not match the true PSF that is convolved with the galaxy light profile. Although the effect of PSF …