Search Publications
Identification of new classical Ae stars in the Galaxy using LAMOST DR5
Arun, R.; Mathew, Blesson; Kartha, Sreeja S. +6 more
We report the first systematic study to identify and characterize a sample of classical Ae stars in the Galaxy. The spectra of these stars were retrieved from the A-star catalogue using the Large sky Area Multi-Object fibre Spectroscopic Telescope (LAMOST) survey. We identified the emission-line stars in this catalogue from which 159 are confirmed…
Proper motions of OB stars in the far Carina Arm
Monguió, M.; Wright, N. J.; Drew, J. E.
In large-scale maps of the Galactic disc, the Carina Arm stands out as a clear spiral feature, hosting prominent star clusters and associations rich in massive stars. We study the proper motions of 4199 O and early B most likely in the far Carina Arm, at distances mainly in excess of 4 kpc from the Sun, within the sky region, 282° < ℓ < 294°…
Jupiter's Auroral Radio Emissions Observed by Cassini: Rotational Versus Solar Wind Control, and Components Identification
Cecconi, B.; Lamy, L.; Zarka, P. +5 more
Reanalyzing Cassini radio observations performed during Jupiter's flyby of 2000-2001, we study the internal (rotational) versus external (solar wind) control of Jupiter's radio emissions, from kilometer to decameter wavelengths, and the relations between the different auroral radio components. For that purpose, we build a database of the occurrenc…
New observations of NGC 1624-2 reveal a complex magnetospheric structure and underlying surface magnetic geometry
Wade, G. A.; Fullerton, A. W.; Shultz, M. E. +5 more
NGC 1624-2 is the most strongly magnetized O-type star known. Previous spectroscopic observations of this object in the ultraviolet provided evidence that it hosts a large and dense circumstellar magnetosphere. Follow-up observations obtained with the Hubble Space Telescope not only confirm that previous inference, but also suggest that NGC 1624-2…
Giant star-forming complexes in high-z main-sequence galaxy analogues: the internal structure of clumps in DYNAMO galaxies
Glazebrook, Karl; Lenkić, Laura; Bolatto, Alberto D. +4 more
To indirectly study the internal structure of giant clumps in main sequence galaxies at z ~ 1-3, we target very turbulent and gas-rich local analogues from the DYNAMO sample with the Hubble Space Telescope, over a wavelength range of ~200-480 nm. We present a catalogue of 58 clumps identified in six DYNAMO galaxies, including the WFC3/UVIS F225W, …
SN 2018agk: A Prototypical Type Ia Supernova with a Smooth Power-law Rise in Kepler (K2)
Pál, András; Barclay, Thomas; Kilpatrick, Charles D. +73 more
We present the 30 minutes cadence Kepler/K2 light curve of the Type Ia supernova (SN Ia) SN 2018agk, covering approximately one week before explosion, the full rise phase, and the decline until 40 days after peak. We additionally present ground-based observations in multiple bands within the same time range, including the 1 day cadence DECam obser…
A Global and Seasonal Perspective of Martian Water Vapor From ExoMars/NOMAD
Aoki, S.; Vandaele, A. C.; Daerden, F. +18 more
Slightly less than a Martian Year of nominal science (March 2018-January 2020) with the ExoMars Trace Gas Orbiter has furthered the ongoing investigation of dayside water vapor column abundance. These dayside observations span latitudes between 75°S and 75°N, and all longitudes, which can provide global snapshots of the total water column abundanc…
An approximate analytic solution to the coupled problems of coronal heating and solar-wind acceleration
Chandran, Benjamin D. G.
Between the base of the solar corona at $r=r_\textrm {b}$ and the Alfvén critical point at $r=r_\textrm {A}$, where $r$ is heliocentric distance, the solar-wind density decreases by a factor $ \mathop > \limits_∼ 10^5$, but the plasma temperature varies by a factor of only a few. In this paper, I show that such quasi-isothermal evolution out to…
Optical spectroscopy of Galactic field classical Be stars
Mathew, Blesson; Paul, K. T.; Subramaniam, Annapurni +3 more
In this study, we analyse the emission lines of different species present in 118 Galactic field classical Be stars in the wavelength range of 3800-9000 Å. We re-estimated the extinction parameter (AV) for our sample stars using the newly available data from Gaia DR2 and suggest that it is important to consider AV while measur…
A Broadband X-Ray View of the Precessing Accretion Disk and Pre-eclipse Dip in the Pulsar Her X-1 with NuSTAR and XMM-Newton
Pottschmidt, Katja; Staubert, Rüdiger; Wilms, Jörn +5 more
We present a broadband X-ray timing study of the variations in pulse behavior with the superorbital cycle in the low-mass X-ray binary Her X-1. This source shows a 35 day superorbital modulation in X-ray flux that is likely caused by occultation by a warped, precessing accretion disk. Our data set consists of four joint XMM-Newton and NuSTAR obser…