@article{EllisBlandHawthornLawrenceetal.2012, author = {Ellis, S. C. and Bland-Hawthorn, Joss and Lawrence, J. and Horton, A. J. and Trinh, C. and Leon-Saval, S. G. and Shortridge, K. and Bryant, J. and Case, S. and Colless, M. and Couch, W. and Freeman, K. and Gers, L. and Glazebrook, K. and Haynes, R. and Lee, S. and L{\"o}hmannsr{\"o}ben, Hans-Gerd and O'Byrne, J. and Miziarski, S. and Roth, M. and Schmidt, B. and Tinney, C. G. and Zheng, J.}, title = {Suppression of the near-infrared OH night-sky lines with fibre Bragg gratings - first results}, series = {Monthly notices of the Royal Astronomical Society}, volume = {425}, journal = {Monthly notices of the Royal Astronomical Society}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2012.21602.x}, pages = {1682 -- 1695}, year = {2012}, abstract = {The background noise between 1 and 1.8 ?mu m in ground-based instruments is dominated by atmospheric emission from hydroxyl molecules. We have built and commissioned a new instrument, the Gemini Near-infrared OH Suppression Integral Field Unit (IFU) System (GNOSIS), which suppresses 103 OH doublets between 1.47 and 1.7?mu m by a factor of 1000 with a resolving power of 10?000. We present the first results from the commissioning of GNOSIS using the IRIS2 spectrograph at the Anglo-Australian Telescope. We present measurements of sensitivity, background and throughput. The combined throughput of the GNOSIS fore-optics, grating unit and relay optics is 36?per cent, but this could be improved to 46?per cent with a more optimal design. We measure strong suppression of the OH lines, confirming that OH suppression with fibre Bragg gratings will be a powerful technology for low-resolution spectroscopy. The integrated OH suppressed background between 1.5 and 1.7 mu m is reduced by a factor of 9 compared to a control spectrum using the same system without suppression. The potential of low-resolution OH-suppressed spectroscopy is illustrated with example observations of Seyfert galaxies and a low-mass star. The GNOSIS background is dominated by detector dark current below 1.67 mu m and by thermal emission above 1.67 mu m. After subtracting these, we detect an unidentified residual interline component of 860 +/- 210 photons s-1 m-2?arcsec-2?mu m-1, comparable to previous measurements. This component is equally bright in the suppressed and control spectra. We have investigated the possible source of the interline component, but were unable to discriminate between a possible instrumental artefact and intrinsic atmospheric emission. Resolving the source of this emission is crucial for the design of fully optimized OH suppression spectrographs. The next-generation OH suppression spectrograph will be focused on resolving the source of the interline component, taking advantage of better optimization for a fibre Bragg grating feed incorporating refinements of design based on our findings from GNOSIS. We quantify the necessary improvements for an optimal OH suppressing fibre spectrograph design.}, language = {en} } @article{OskinovaBulikGomezMoran2018, author = {Oskinova, Lida and Bulik, Tomasz and Gomez-Moran, Ada Nebot}, title = {Infrared outbursts as potential tracers of common-envelope events in high-mass X-ray binary formation}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {613}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/201832925}, pages = {7}, year = {2018}, abstract = {Context. Classic massive binary evolutionary scenarios predict that a transitional common-envelope (CE) phase could be preceded as well as succeeded by the evolutionary stage when a binary consists of a compact object and a massive star, that is, a high-mass X-ray binary (HMXB). The observational manifestations of common envelope are poorly constrained. We speculate that its ejection might be observed in some cases as a transient event at mid-infrared (IR) wavelengths. Aims. We estimate the expected numbers of CE ejection events and HMXBs per star formation unit rate, and compare these theoretical estimates with observations. Methods. We compiled a list of 85 mid-IR transients of uncertain nature detected by the Spitzer Infrared Intensive Transients Survey and searched for their associations with X-ray, optical, and UV sources. Results. Confirming our theoretical estimates, we find that only one potential HMXB may be plausibly associated with an IR-transient and tentatively propose that X-ray source NGC4490-X40 could be a precursor to the SPIRITS 16az event. Among other interesting sources, we suggest that the supernova remnant candidate [BWL2012] 063 might be associated with SPIRITS 16ajc. We also find that two SPIRITS events are likely associated with novae, and seven have potential optical counterparts. Conclusions. The massive binary evolutionary scenarios that involve CE events do not contradict currently available observations of IR transients and HMXBs in star-forming galaxies.}, language = {en} }