Search Publications
A treatment procedure for Gemini North/NIFS data cubes: application to NGC 4151
Ricci, T. V.; Steiner, J. E.; Menezes, R. B.
We present a detailed procedure for treating data cubes obtained with the Near-Infrared Integral Field Spectrograph (NIFS) of the Gemini North telescope. This process includes the following steps: correction of the differential atmospheric refraction, spatial re-sampling, Butterworth spatial filtering, `instrumental fingerprint' removal and Richar…
Feeding versus feedback in NGC 1068 probed with Gemini NIFS - I. Excitation
Storchi-Bergmann, Thaisa; Riffel, Rogemar A.; McGregor, Peter J. +1 more
We present emission-line flux distributions and ratios for the inner ≈200 pc of the narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068, using observations obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in the J, H and K bands at a spatial resolution of ≈10 pc and spectral resolution of ≈5300. The molecular gas emi…
Herschel-ATLAS: far-infrared properties of radio-loud and radio-quiet quasars
Ivison, R. J.; de Zotti, G.; Ibar, E. +11 more
We have constructed a sample of radio-loud and radio-quiet quasars from the Faint Images Radio Sky at Twenty-one centimetres and the Sloan Digital Sky Survey Data Release 7, over the Herschel-ATLAS Phase 1 area (9h, 12h and 14{h.}5). Using a stacking analysis, we find a significant correlation between th…
Abundance stratification in Type Ia supernovae - IV. The luminous, peculiar SN 1991T
Pian, E.; Cappellaro, E.; Benetti, S. +4 more
The abundance distribution of the elements in the ejecta of the peculiar, luminous Type Ia supernova (SN Ia) 1991T is obtained modelling spectra from before maximum light until a year after the explosion, with the method of `Abundance Tomography'. SN 1991T is different from other slowly declining SNe Ia (e.g. SN 1999ee) in having a weaker Si II 63…
Cumulative luminosity distributions of supergiant fast X-ray transients in hard X-rays
Sidoli, L.; Paizis, A.
We have analysed in a systematic way about nine years of INTEGRAL data (17-100 keV) focusing on supergiant fast X-ray transients (SFXTs) and three classical high-mass X-ray binaries (HMXBs). Our approach has been twofold: image-based analysis, sampled over a ∼ks time frame to investigate the long-term properties of the sources and light-curve-base…
No excess of bright galaxies around the redshift 7.1 quasar ULAS J1120+0641
Simpson, Chris; Cantalupo, Sebastiano; Venemans, Bram +5 more
We present optical and near-infrared imaging of the field of the z = 7.0842 quasar ULAS J112001.48+064124.3 taken with the Hubble Space Telescope. We use these data to search for galaxies that may be physically associated with the quasar, using the Lyman break technique, and find three such objects, although the detection of one in Spitzer Space T…
The quiescent X-ray spectrum of accreting black holes
Reis, Rubens C.; Miller, Jon M.; Cackett, Edward M. +2 more
The quiescent state is the dominant accretion mode for black holes on all mass scales. Our knowledge of the X-ray spectrum is limited due to the characteristic low luminosity in this state. Herein, we present an analysis of the sample of dynamically confirmed stellar-mass black holes observed in quiescence in the Chandra/XMM-Newton/Suzaku era resu…
Formation history of polycyclic aromatic hydrocarbons in galaxies
Seok, Ji Yeon; Hirashita, Hiroyuki; Asano, Ryosuke S.
Polycyclic aromatic hydrocarbons (PAHs) are some of the major dust components in the interstellar medium (ISM). We present our evolution models for the abundance of PAHs in the ISM on a galaxy-evolution time-scale. We consider shattering of carbonaceous dust grains in interstellar turbulence as the formation mechanism of PAHs while the PAH abundan…
Astrometric follow-up observations of directly imaged sub-stellar companions to young stars and brown dwarfs
Neuhäuser, R.; Schmidt, T. O. B.; Ginski, C. +4 more
The formation of massive planetary or brown dwarf companions at large projected separations from their host star is not yet well understood. In order to put constraints on formation scenarios, we search for signatures in the orbit dynamics of the systems. We are specifically interested in the eccentricities and inclinations since those parameters …
Caught in the act: measuring the changes in the corona that cause the extreme variability of 1H 0707-495
Fabian, A. C.; Gallo, L. C.; Kara, E. +1 more
The X-ray spectra of the narrow-line Seyfert 1 galaxy, 1H 0707-495, obtained with XMM-Newton, from time periods of varying X-ray luminosity are analysed in the context of understanding the changes to the X-ray emitting corona that lead to the extreme variability seen in the X-ray emission from active galactic nuclei (AGN). The emissivity profile o…