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On the origin of core radio emissions from black hole sources in the realm of relativistic shocked accretion flow
Stalin, C. S.; Rakshit, Suvendu; Nandi, Anuj +5 more
We study the relativistic, inviscid, advective accretion flow around the black holes and investigate a key feature of the accretion flow, namely the shock waves. We observe that the shock-induced accretion solutions are prevalent and such solutions are commonly obtained for a wide range of the flow parameters, such as energy (${\cal E}$) and angul…
NGTS-21b: an inflated Super-Jupiter orbiting a metal-poor K dwarf
Wheatley, Peter J.; Bayliss, Daniel; Worters, Hannah L. +29 more
We report the discovery of NGTS-21b , a massive hot Jupiter orbiting a low-mass star as part of the Next Generation Transit Survey (NGTS). The planet has a mass and radius of 2.36 ± 0.21 MJ and 1.33 ± 0.03 RJ, and an orbital period of 1.543 d. The host is a K3V (Teff = 4660 ± 41 K) metal-poor ([Fe/H] = -0.26 ± 0.07…
TUVOpipe: A pipeline to search for UV transients with Swift-UVOT
Wijnands, Rudy; Modiano, David; Parikh, Aastha +3 more
Despite the prevalence of transient-searching facilities operating across most wavelengths, the ultraviolet (UV) transient sky remains to be systematically studied. Therefore, we recently initiated the Transient Ultraviolet Objects (TUVO) project, with which we search for serendipitous UV transients in data obtained using currently available UV in…
Redshift and stellar mass dependence of intrinsic shapes of disc-dominated galaxies from COSMOS observations below z = 1.0
Tallada-Crespí, P.; Teyssier, R.; Laigle, C. +4 more
The high abundance of disc galaxies without a large central bulge challenges predictions of current hydrodynamic simulations of galaxy formation. We aim to shed light on the formation of these objects by studying the redshift and mass dependence of their intrinsic 3D shape distributions in the COSMOS galaxy survey below redshift z = 1.0. This dist…
NuSTAR discovery of the hard X-ray emission and a wide-band X-ray spectrum from the Pictor A western hotspot
Katsuda, Satoru; Sato, Kosuke; Tashiro, Makoto S. +5 more
Utilizing Chandra, XMM-Newton, and NuSTAR, a wide-band X-ray spectrum from 0.2 to 20 keV is reported from the western hotspot of Pictor A. In particular, the X-ray emission is significantly detected in the 3 to 20 keV band at 30σ by NuSTAR. This is the first detection of hard X-rays with energies above 10 keV from a jet termination hotspot of acti…
SPHERE adaptive optics performance for faint targets
Jones, M. I.; Milli, J.; Blanchard, I. +4 more
Context. High-contrast imaging is a powerful technique for detecting and characterizing planetary companions at orbital separations ≳100 mas from their parent stars.
Aims: We aim to study the limiting magnitude of the VLT/SPHERE adaptive optics (AO) system and the corresponding instrument performance for faint targets (G ≥ 11.0 mag).
Met…
Multi-Spacecraft Observations of an Interplanetary Coronal Mass Ejection Interacting with Two Solar-Wind Regimes Observed by the Ulysses and Twin-STEREO Spacecraft
Foullon, Claire; Barnes, David; Davies, Jackie +2 more
We present a combined study of a coronal mass ejection (CME), revealed in a unique orbital configuration that permits the analysis of remote-sensing observations on 27 June 2007 from the twin Solar Terrestrial Relations Observatory (STEREO)-A and -B spacecraft and of its subsequent in situ counterpart outside the ecliptic plane, the interplanetary…
Complex Catalogue of High Speed Streams Associated with Geomagnetic Storms During Solar Cycle 24
Besliu-Ionescu, Diana; Maris Muntean, Georgeta; Dobrica, Venera
A complex catalogue of high speed streams produced by coronal holes and their effects in the terrestrial magnetosphere - the so-called geomagnetic storms - for Solar Cycle 24 (2009 to 2019) is presented here. This catalogue is structured in three parts describing the high-speed stream characteristics, the interplanetary magnetic field state, and t…
He II Lyα Transmission Spikes and Absorption Troughs in Eight High-resolution Spectra Probing the End of He II Reionization
Richter, Philipp; Hennawi, Joseph F.; Worseck, Gábor +3 more
We present statistics of He II Lyα transmission spikes and large-scale absorption troughs using archival high-resolution (R = λ/Δλ ≃ 12,500-18,000) far-UV spectra of eight He II-transparent quasars obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. The sample covers the redshift range 2.5 ≲ z ≲ 3.8, thereby probing the ra…
Spectral Signs of Simultaneous Sublimation Activity and the Appearance of a Dust Exosphere on Eight Asteroids of the Main Belt Near Perihelion
Shcherbina, M. P.; Busarev, V. V.; Savelova, A. A. +1 more
In December 2020, at the 2-m telescope of the Terskol branch of the Institute of Astronomy, we carried out spectrophotometric observations in the range of ~0.36-0.95 µm of nine asteroids of the Main Belt (19 Fortuna, 52 Europa, 102 Miriam, 177 Irma, 203 Pompeja, 250 Bettina, 266 Aline, 379 Huenna, and 383 Janina), which were near perihelia o…