Search Publications
Emergence of small-scale magnetic flux in the quiet Sun
Gontikakis, C.; Tziotziou, K.; Tsiropoula, G. +4 more
Context. We study the evolution of a small-scale emerging flux region (EFR) in the quiet Sun, from its emergence in the photosphere to its appearance in the corona and its decay.
Aims: We track processes and phenomena that take place across all atmospheric layers; we explore their interrelations and compare our findings with those from recent…
The Large-scale Behavior in the Disk of δ Scorpii from 2000 to 2018
Carciofi, A. C.; Mota, B. C.; Tycner, C. +4 more
We model the circumstellar disk of δ Sco using the three-dimensional Monte Carlo radiative transfer code HDUST in order to quantify the large-scale changes in the disk through the years 2000-2018, and to see if these changes can be attributed to the secondary star affecting the disk throughout its orbit. We determine our best-fitting models throug…
Resolved star formation in the metal-poor star-forming region Magellanic Bridge C
Bolatto, Alberto D.; Rubio, Monica; Kalari, Venu M. +1 more
Magellanic Bridge C (MB-C) is a metal-poor (∼1/5 Z⊙) low-density star-forming region located 59 kpc away in the Magellanic Bridge, offering a resolved view of the star formation process in conditions different to the Galaxy. From Atacama Large Millimetre Array CO (1-0) observations, we detect molecular clumps associated with candidate y…
Present-day gully activity in Sisyphi Cavi, Mars - Flow-like features and block movements
Massé, Marion; Conway, Susan J.; Hiesinger, Harald +5 more
The continuously increasing number of multi-temporal high-resolution images from the surface of Mars offers the possibility for detailed studies of present-day surface activity. In this study we investigated all gullies in the Sisyphi Cavi region (355° E, 71° S) of the south polar region of Mars. This region is influenced by the seasonal depositio…
Multiwavelength Study of an X-Ray Tidal Disruption Event Candidate in NGC 5092
Komossa, S.; Jin, Chichuan; Saxton, R. D. +7 more
We present multiwavelength studies of a transient X-ray source, XMMSL1 J131952.3+225958, associated with the galaxy NGC 5092 at z = 0.023 detected in the XMM-Newton SLew survey (XMMSL). The source brightened in the 0.2-2 keV band by a factor of > 20 in 2005 as compared with previous flux limits and then faded by a factor of >200 as observed …
Prebreakup Arc Intensification due to Short Circuiting of Mesoscale Plasma Flows Over the Plasmapause
Mishin, Evgeny; Streltsov, Anatoly
The prebreakup arc at the inner edge of the auroral boundary is intensified upon arrival of an auroral streamer—the ionospheric signature of the earthbound mesoscale plasma flows (MPF). Yet the cause of electron precipitation enhancement only in this region remains unclear. We suggest that the intensified precipitation comes from the turbulent pla…
Evidence for a Rotational Component in the Circumgalactic Medium of Nearby Galaxies
Wakker, Bart P.; French, David M.
We present results of a study comparing the relative velocity of Lyα absorbers to the rotation velocity of nearby galaxy disks in the local universe (z ≤ 0.03). We have obtained rotation curves via long-slit spectroscopy of eight galaxies with the Southern African Large Telescope, and combine this data set with an additional 16 galaxies with data …
Hierarchical star formation in nearby galaxies
Baume, G.; Rodríguez, M. J.; Feinstein, C.
Aims: The purpose of this work is to study the properties of the spatial distribution of the young population in three nearby galaxies in order to better understand the first stages of star formation.
Methods: We used ACS/HST photometry and the "path-linkage criterion" in order to obtain a catalog of young stellar groups (YSGs) in the ga…
Probing the nuclear and circumnuclear properties of NGC 6300 using X-ray observations
Naik, Sachindra; Jana, Arghajit; Chatterjee, Arka +3 more
We present the results obtained from a detailed X-ray timing and spectral analysis of the Seyfert 2 galaxy NGC 6300 by using observations from the Suzaku observatory, theChandra X-ray Observatory and the Nuclear Spectroscopic Telescope Array(NuSTAR) mission between 2007 and 2016. We calculate the variance and the rms fractional variability of the …
ASKAP reveals giant radio halos in two merging SPT galaxy clusters
Johnston-Hollitt, Melanie; Akamatsu, Hiroki; Hodgson, Torrance +4 more
Early science observations from the Australian Square Kilometre Array Pathfinder (ASKAP) have revealed clear signals of diffuse radio emission associated with two clusters detected by the South Pole Telescope via their Sunyaev Zel'dovich signal: SPT CLJ0553-3342 (MACS J0553.4-3342) and SPT CLJ0638-5358 (Abell S0592) are both high-mass lensing clus…