Search Publications
X-ray-emitting active galactic nuclei from z = 0.6 to 1.3 in the intermediate- and high-density environments of the ORELSE survey
Tomczak, A.; Fassnacht, C. D.; Kocevski, D. D. +8 more
We studied active galactic nucleus (AGN) activity in 12 large-scale structures (LSSs) in the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey, at 0.65 < z < 1.28, using a combination of Chandra observations, optical and NIR imaging and spectroscopy. We located a total of 61 AGNs that were successfully matched to…
Neutron-capture element abundances in the planetary nebula NGC 5315 from deep optical and near-infrared spectrophotometry★†
Madonna, S.; García-Rojas, J.; Sterling, N. C. +5 more
We analyse the chemical composition of the planetary nebula (PN) NGC 5315, through high-resolution (R ∼ 40000) optical spectroscopy with Ultraviolet-Visual Echelle Spectrograph at the Very Large Telescope, and medium-resolution (R ∼ 4800) near-infrared spectroscopy with Folded-port InfraRed Echellette at Magellan Baade Telescope, covering a wide s…
Cometary coma dust size distribution from in situ IR spectra
Fulle, M.; Mottola, S.; D'Aversa, E. +16 more
Dust is the most abundant component in cometary comae. Here, we investigate the dust size distribution in 67P/Churyumov-Gerasimenko (67P/CG) using data from the Rosetta spacecraft that was in close proximity to the comet from 2014 August to 2016 September. The Visual, Infrared and Thermal Imaging Spectrometer (VIRTIS-M), spectral range of 0.25-5 &…
Characterization of dust aggregates in the vicinity of the Rosetta spacecraft
Jorda, L.; Lamy, P. L.; Lara, L. M. +49 more
In a Rosetta/OSIRIS imaging activity in 2015 June, we have observed the dynamic motion of particles close to the spacecraft. Due to the focal setting of the OSIRIS wide angle camera, these particles were blurred, which can be used to measure their distances to the spacecraft. We detected 109 dust aggregates over a 130 min long sequence, and find t…
Rapid X-ray variability properties during the unusual very hard state in neutron-star low-mass X-ray binaries
Altamirano, D.; Degenaar, N.; Wijnands, R. +2 more
Here, we study the rapid X-ray variability (using XMM-Newton observations) of three neutron-star low-mass X-ray binaries (1RXS J180408.9-342058, EXO 1745-248 and IGR J18245-2452) during their recently proposed very hard spectral state. All our systems exhibit a strong to very strong noise component in their power density spectra (rms amplitudes ra…
Wavelet reconstruction of E and B modes for CMB polarization and cosmic shear analyses
Leistedt, Boris; Peiris, Hiranya V.; McEwen, Jason D. +1 more
We present new methods for mapping the curl-free (E-mode) and divergence-free (B-mode) components of spin 2 signals using spin directional wavelets. Our methods are equally applicable to measurements of the polarization of the cosmic microwave background (CMB) and the shear of galaxy shapes due to weak gravitational lensing. We derive pseudo- and …
Gas inflows towards the nucleus of the Seyfert 2 galaxy NGC 1667
Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa; Nagar, Neil M. +1 more
We use optical spectra from the inner 2 × 3 kpc2 of the Seyfert 2 galaxy NGC 1667, obtained with the Gemini Multi-Object Spectrograph integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈240 pc, to assess the feeding and feedback processes in this nearby active galactic nucleus (AGN). We have identified …
The stellar mass-size relation for cluster galaxies at z = 1 with high angular resolution from the Gemini/GeMS multiconjugate adaptive optics system
Glazebrook, Karl; Abraham, Roberto; Bayliss, Matthew +7 more
We present the stellar mass-size relation for 49 galaxies within the z = 1.067 cluster SPT-CL J0546-5345, with full width at half-maximum ∼80-120 mas Ks-band data from the Gemini multiconjugate adaptive optics system (GeMS/GSAOI). This is the first such measurement in a cluster environment, performed at sub-kpc resolution at rest-frame …
Simultaneous optical/X-ray study of GS 1354-64 (=BW Cir) during hard outburst: evidence for optical cyclo-synchrotron emission from the hot accretion flow
Gandhi, Poshak; Altamirano, Diego; Misra, Ranjeev +3 more
We present results from simultaneous optical [South African Large Telescope (SALT)] and X-ray (Swift and INTEGRAL) observations of GS 1354-64/BW Cir during the 2015 hard state outburst. During the rising phase, optical/X-ray time series shows a strong anti-correlation with X-ray photons lagging optical. Optical and X-ray power spectra show quasi-p…
Soft extragalactic X-ray binaries at the Eddington Threshold
Roberts, Timothy P.; Earnshaw, Hannah M.
The luminosity range at and just below the 1039 erg s-1 cut-off for defining ultraluminous X-ray sources (ULXs) is a little-explored regime. It none the less hosts a large number of X-ray sources, and has great potential for improving our understanding of sources with ∼Eddington accretion rates. We select a sample of four sou…