Search Publications
Calibration of Herschel SPIRE FTS observations at different spectral resolutions
Valtchanov, I.; Hopwood, R.; Spencer, L. +11 more
The SPIRE Fourier Transform Spectrometer on-board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode revealed a systematic di…
Superwind evolution: the young starburst-driven wind galaxy NGC 2782
Stevens, Ian R.; Bravo-Guerrero, Jimena
We present results from a 30-ks Chandra observation of the important starburst galaxy NGC 2782, covering the 0.3-10 keV energy band. We find evidence of a superwind of small extent, which is likely in an early stage of development. We find a total of 27 X-ray point sources within a region of radius 2D25 of the galaxy centre and that are…
Dust scattering from the Taurus Molecular Cloud
Murthy, Jayant; Narayan, Sathya; Karuppath, Narayanankutty
We present an analysis of the diffuse ultraviolet emission near the Taurus Molecular Cloud based on observations made by the Galaxy Evolution Explorer. We used a Monte Carlo dust scattering model to show that about half of the scattered flux originates in the molecular cloud with 25 per cent arising in the foreground and 25 per cent behind the clo…
Hubble Space Telescope observations of BALQSO Ton 34 reveal a connection between the broad-line region and the BAL outflow
Binette, L.; Bianchi, L.; Nicastro, F. +7 more
Ton 34 recently transitioned from non-absorbing quasar into a broad absorption line quasi-stellar object. Here, we report new HST-STIS observations of this quasar. Along with C IV absorption, we also detect absorption by NV+Lyα and possibly O VI+Lyβ. We follow the evolution of the C IV BAL, and find that, for the slower outflowing material, the ab…
Local two-sample testing: a new tool for analysing high-dimensional astronomical data
Freeman, P. E.; Kim, I.; Lee, A. B.
Modern surveys have provided the astronomical community with a flood of high-dimensional data, but analyses of these data often occur after their projection to lower dimensional spaces. In this work, we introduce a local two-sample hypothesis test framework that an analyst may directly apply to data in their native space. In this framework, the an…
On the signatures of flare-induced global waves in the Sun: GOLF and VIRGO observations
García, Rafael A.; Kumar, Brajesh; Mathur, Savita +1 more
Recently, several efforts have been made to identify the seismic signatures of flares and magnetic activity in the Sun and Sun-like stars. In this work, we have analysed the disc-integrated velocity and intensity observations of the Sun obtained from the Global Oscillations at Low Frequencies (GOLF) and Variability of solar IRradiance and Gravity …
Application of beam deconvolution technique to power spectrum estimation for CMB measurements
Keihänen, E.; Kurki-Suonio, H.; Reinecke, M. +1 more
We present two novel methods for the estimation of the angular power spectrum of cosmic microwave background (CMB) anisotropies. We assume an absolute CMB experiment with arbitrary asymmetric beams and arbitrary sky coverage. The methods differ from the earlier ones in that the power spectrum is estimated directly from the time-ordered data, witho…
The highly ionized, high-velocity gas in NGC 6231
Massa, Derck
It is well known that clusters of massive stars are influenced by the presence of strong winds, that they are sources of diffuse X-rays from shocked gas, and that this gas can be vented into the surrounding region or the halo through the champagne effect. However, the details of how these different environments interact and evolve are far from com…
A three-dimensional orbit for the binary star Alpha Andromedae
Branham, Richard L., Jr.
Stars that are both spectroscopic and optical binaries present a means to determine simultaneously the masses of the components and the distance of the system independent of trigonometric parallax. Alpha Andromedae (Alpheratz) represents such a system and, moreover, the primary is the brightest of the mercury-manganese stars. An orbit, based on 42…
Detection of helicoidal motion in the optical jet of PKS 0521-365
Jiménez-Andrade, E. F.; Falomo, R.; Chavushyan, V. +5 more
The jet activity of active galactic nuclei (AGNs), and its interaction with the interstellar medium, may play a pivotal role in the processes that regulate the growth and star formation of its host galaxy. Observational evidence that pinpoints the conditions of such interaction is paramount to unveil the physical processes involved. We report on t…