Eamonn Harvey - Academia.edu (original) (raw)

Papers by Eamonn Harvey

Monthly Notices of the Royal Astronomical Society, 2021

We analyse high-resolution spectra of two classical novae that exploded in the Small Magellanic C... more We analyse high-resolution spectra of two classical novae that exploded in the Small Magellanic Cloud (SMC). 7Be ii resonance transitions are detected in both ASASSN-19qv and ASASSN-20ni novae. This is the first detection outside the Galaxy and confirms that thermo-nuclear runaway reactions, leading to the 7Be formation, are effective also in the low-metallicity regime, characteristic of the SMC. Derived yields are of N(7Be = 7Li)/N(H) = (5.3 ± 0.2) × 10−6 which are a factor 4 lower than the typical values of the Galaxy. Inspection of two historical novae in the Large Magellanic Cloud observed with IUE in 1991 and 1992 showed also the possible presence of 7Be and similar yields. For an ejecta of MH, ej = 10−5 M⊙, the amount of 7Li produced is of M7Li=(3.7pm0.6)times10−10M_{^7 Li} = (3.7 \pm 0.6) \times 10^{-10}M7Li=(3.7pm0.6)times10−10 M⊙ per nova event. Detailed chemical evolutionary model for the SMC shows that novae could have made an amount of lithium in the SMC corresponding to a fractional abundance of A(Li) ≈ 2.6. Therefo...

Astronomy & Astrophysics, 2020

Aims. Our aim is to study the mass transfer, accretion environment, and wind outflows in the SS 4... more Aims. Our aim is to study the mass transfer, accretion environment, and wind outflows in the SS 433 system, concentrating on the so-called stationary lines. Methods. We used archival high-resolution (X-shooter) and low-resolution (EMMI) optical spectra, new optical multi-filter polarimetry, and low-resolution optical spectra (Liverpool Telescope), spanning an interval of a decade and a broad range of precessional and orbital phases, to derive the dynamical properties of the system. Results. Using optical interstellar absorption lines and H I 21 cm profiles, we derive E(B − V) = 0.86 ± 0.10, with an upper limit of E(B − V) = 1.8 ± 0.1 based on optical Diffuse Interstellar Bands. We obtain revised values for the ultraviolet and U band polarizations and polarization angles (PA), based on a new calibrator star at nearly the same distance as SS 433 that corrects the published measurement and yields the same PA as the optical. The polarization wavelength dependence is consistent with opti...

Astronomy & Astrophysics, 2015

Context. Complex bipolar shapes can be generated either as a planetary nebula or a symbiotic syst... more Context. Complex bipolar shapes can be generated either as a planetary nebula or a symbiotic system. The origin of the material ionised by the white dwarf is very different in these two scenarios, and it complicates the understanding of the morphologies of planetary nebulae. Aims. The physical properties, structure, and dynamics of the bipolar nebulae, M 2−9, Mz 3, and Hen 2−104, are investigated in detail with the aim of understanding their nature, shaping mechanisms, and evolutionary history. Both a morpho-kinematic study and a spectroscopic analysis, can be used to more accurately determine the kinematics and nature of each nebula. Methods. Long-slit optical echelle spectra are used to investigate the morpho-kinematics of M 2−9, Mz 3, and Hen 2−104. The morpho-kinematic modelling software SHAPE is used to constrain both the morphology and kinematics of each nebula by means of detailed 3D models. Near-infrared (NIR) data, as well as optical, spectra are used to separate Galactic symbiotic-type nebulae from genuine planetary nebulae by means of a 2MASS J−H/H−Ks diagram and a λ4363/Hγ vs. λ5007/Hβ diagnostic diagram, respectively. Results. The best-fitted 3D models for M 2−9, Mz 3, and Hen 2−104 provide invaluable kinematical information on the expansion velocity of its nebular components by means of synthetic spectra. The observed spectra match up very well with the synthetic spectra for each model, thus showing that each model is tightly constrained both morphologically and kinematically. Kinematical ages of the different structures of M 2−9 and Mz 3 have also been determined. Both diagnostic diagrams show M 2−9 and Hen 2−104 to fall well within the category of having a symbiotic source, whereas Mz 3 borders the region of symbiotic and young planetary nebulae in the optical diagram but is located firmly in the symbiotic region of the NIR colour−colour diagram. The optical diagnostic diagram is shown to successfully separate the two types of nebulae, however, the NIR colour−colour diagram is not as accurate in separating these objects. Conclusions. The morphology, kinematics, and evolutionary history of M 2−9, Mz 3, and Hen 2−104 are better understood using the interactive 3D modelling tool . The expansion velocities of the components for each nebula are better constrained and fitted with a vector field to reveal their direction of motion. The optical and NIR diagnostic diagrams used are important techniques for separating Galactic symbiotic-type nebulae from genuine planetary nebulae.

Astronomy & Astrophysics, 2012

Monthly Notices of the Royal Astronomical Society, 2010

The unique Honeycomb nebula, most likely a peculiar supernova remnant, lies in 30 Doradus in the ... more The unique Honeycomb nebula, most likely a peculiar supernova remnant, lies in 30 Doradus in the Large Magellanic Cloud (LMC). Due to its proximity to SN1987A, it has been serendipitously and intentionally observed at many wavelengths. Here, an optical spectral analysis of forbidden line ratios is performed in order to compare the Honeycomb high-speed gas with supernova remnants in the Galaxy and the LMC, with Galactic Wolf-Rayet nebulae and with the optical line emission from the interaction zone of the SS433 microquasar and W50 supernova remnant system. An empirical spatiokinematic model of the images and spectra for the Honeycomb reveals that its striking appearance is most likely due to a fortuitous viewing angle. The Honeycomb nebula is more extended in soft X-ray emission and could in fact be a small part of the edge of a giant LMC shell revealed for the first time in this short wavelength domain. It is also suggested that a previously unnoticed region of optical emission may in fact be an extension of the Honeycomb around the edge of this giant shell. A secondary supernova explosion in the edge of a giant shell is considered for the creation of the Honeycomb nebula. A microquasar origin of the Honeycomb nebula as opposed to a simple supernova origin is also evaluated.

Ground-based and Airborne Telescopes VIII

The New Robotic Telescope is designed to conduct rapid target follow-up within 30 seconds of an ‘... more The New Robotic Telescope is designed to conduct rapid target follow-up within 30 seconds of an ‘alert’ from survey facilities. To achieve this will require a quick settling time requirement for the mount structure and the mirrors. This means the structure shall be designed to be sufficiently rigid to achieve the mirror position within the ‘settle time’ after a quick slew operation. An optimization analysis using the finite element model is developed to conceptually design the mount structure that meets the mechanical and more importantly the NRT science requirements. The main objective of this study is to determine the required locked rotor resonance frequency (LRF) that provides enough rigidity for the telescope dynamic performance while minimizing the structural mass and cost.