Search Publications
The time delay of CLASS B1600+434 from VLA multi-frequency and polarization monitoring
Biggs, A. D.
We present an analysis of archival multi-frequency Very Large Array monitoring data of the two-image gravitational lens system CLASS B1600+434, including the polarization properties at 8.5 GHz. From simulating radio light curves incorporating realistic external variability in image A, we find time delays consistent at 1σ for all frequencies and in…
HH 175: a giant Herbig-Haro flow emanating from a multiple protostar
Friberg, Per; Reipurth, Bo
HH 175 is an isolated Herbig-Haro object seen towards the B35 cloud in the λ Ori region. We use deep Subaru 8 m interference filter images and Spitzer images to show that HH 175 is a terminal shock in a large collimated outflow from the nearby embedded source IRAS 05417+0907. The body of the eastern outflow lobe is hidden by a dense ridge of gas. …
The former companion of hyper-velocity star S5-HVS1
Hosek, Matthew W., Jr.; Li, Ting S.; Do, Tuan +4 more
The hyper-velocity star S5-HVS1, ejected 5 Myr ago from the Galactic Centre at 1800 km s-1, was most likely produced by tidal break-up of a tight binary by the supermassive black hole SgrA*. Taking a Monte Carlo approach, we show that the former companion of S5-HVS1 was likely a main-sequence star between 1.2 and 6 M⊙ and was…
X-ray reverberation models of the disc wind in ultraluminous X-ray source NGC 5408 X-1
Chainakun, P.; Luangtip, W.; Loekkesee, S. +3 more
Majority of ultraluminous X-ray sources (ULXs) are believed to be super-Eddington objects, providing a nearby prototype for studying an accretion in supercritical regime. In this work, we present the study of time-lag spectra of the ULX NGC 5408 X-1 using a reverberation mapping technique. The time-lag data were binned using two different methods:…
Potential and sky coverage for off-axis fringe tracking in optical long baseline interferometry
Hadjara, Massinissa; Benkhaldoun, Zouhair; Boskri, Abdelkarim +6 more
The spectacular results provided by the second-generationVLTI instruments GRAVITY and MATISSE on active galactic nuclei (AGN) trigger and justify a strong increase in the sensitivity limit of optical interferometers. A key component of such an upgrade is off-axis fringe tracking. To evaluate its potential and limitations, we describe and analyse i…
ASASSN-14lp: two possible solutions for the observed ultraviolet suppression
Foley, Ryan J.; Kerzendorf, Wolfgang; Kromer, Markus +10 more
We test the adequacy of ultraviolet (UV) spectra for characterizing the outer structure of Type Ia supernova (SN) ejecta. For this purpose, we perform spectroscopic analysis for ASASSN-14lp, a normal SN Ia showing low continuum in the mid-UV regime. To explain the strong UV suppression, two possible origins have been investigated by mapping the ch…
Chlorine-bearing species and the 37Cl/35Cl isotope ratio in the coma of comet 67P/Churyumov-Gerasimenko
De Keyser, Johan; Wurz, Peter; Altwegg, Kathrin +6 more
A full-mission analysis has been conducted of Cl-bearing species in the coma of comet 67P/Churyumov-Gerasimenko as detected by the Double Focusing Mass Spectrometer (DFMS) of Rosetta's ROSINA instrument. The isotope ratio of the two stable chlorine isotopes 37Cl/35Cl is found to be 0.336 ± 0.017, to be compared with the stand…
The onset of jets in classical novae
Blundell, Katherine M.; Lee, Steven; McLoughlin, Dominic +1 more
We present two further classical novae, V906 Car and V5668 Sgr, which show jets and accretion disc spectral signatures in their H α complexes throughout the first 1000 d following their eruptions. From extensive densely time-sampled spectroscopy, we measure the appearance of the first high-velocity absorption component in V906 Car, and the duratio…
A multiline study of the filamentary infrared dark cloud G351.78-0.54
Zinchenko, I. I.; Ryabukhina, O. L.
We present results of a multiline study of the filamentary infrared dark cloud G351.78-0.54 in the 1.3 and 0.8 mm wavelength bands. The lines of the three isotopologues of carbon monoxide CO, N2H+, CH3CCH, and HNCO were observed. The aim was to study the general structure of the filamentary cloud, its fragmentation…
Hot graphite dust in the inner regime of NGC 4151
Shalima, P.; Swain, Subhashree; Latha, K. V. P. +1 more
We model the near-infrared (NIR) spectral energy distribution (SED) of NGC 4151 with a 3D radiative transfer SKIRT code, using which torus only (TO) and ring and torus (RAT) scenarios are studied. In the RAT models, a graphite ring-like structure (clumpy or smooth) is incorporated between the torus and the accretion disc. We vary the inclination a…