Search Publications
Large Binocular Telescope observations of PSR J2043+2740*
Marelli, M.; Rea, N.; Mignani, R. P. +5 more
We present the results of deep optical imaging of the radio/γ-ray pulsar PSR J2043+2740, obtained with the Large Binocular Telescope (LBT). With a characteristic age of 1.2 Myr, PSR J2043+2740 is one of the oldest (non-recycled) pulsars detected in γ-rays, although with still a quite high rotational energy reservoir (\dot{E}_rot = 5.6 × 10^{34} er…
AMI-CL J0300+2613: a Galactic anomalous-microwave-emission ring masquerading as a galaxy cluster
Feroz, Farhan; Grainge, Keith J. B.; Hobson, Michael P. +17 more
The Arcminute Microkelvin Imager (AMI) carried out a blind survey for galaxy clusters via their Sunyaev-Zel'dovich effect decrements between 2008 and 2011. The first detection, known as AMI-CL J0300+2613, has been reobserved with AMI equipped with a new digital correlator with high dynamic range. The combination of the new AMI data and more recent…
Abundance patterns of evolved stars with Hipparcos parallaxes and ages based on the APOGEE data base
Zhao, G.; Chen, Y. Q.; Zhao, J. K. +3 more
We investigate the abundance patterns for four groups of stars at evolutionary phases from sub-giant to red clump (RC) and trace the chemical evolution of the disc by taking 21 individual elemental abundances from APOGEE and ages from evolutionary models with the aid of Hipparcos distances. We find that the abundances of six elements (Si, S, K, Ca…
Dramatic X-ray spectral variability of a Compton-thick type-1 QSO at z ∼ 1
Buchner, J.; Nandra, K.; Merloni, A. +6 more
We report on the discovery of a dramatic X-ray spectral variability event observed in a z ∼ 1 broad line type-1 QSO. The XMM-Newton spectrum from the year 2000 is characterized by an unobscured power-law spectrum with photon index of Γ ∼ 2, a column density of NH∼ 5× 10^{20} cm^{-2}, and no prominent reflection component. Five years lat…
Spectral energy distribution variations of nearby Seyfert galaxies during AGN watch monitoring programs
Vestergaard, M.; Kilerci Eser, Ece
We present and analyse quasi-simultaneous multi-epoch spectral energy distributions (SEDs) of seven reverberation-mapped active galactic nuclei (AGNs) for which accurate black hole mass measurements and suitable archival data are available from the `AGN Watch' monitoring programs. We explore the potential of optical-UV and X-ray data, obtained wit…
Magnetic evolution linked to the interrelated activity complexes involving transequatorial coronal holes
Gutiérrez, Heidy; Taliashvili, Lela; Lazarian, Alexandre
We studied a magnetic evolution linked to a cadence of interrelated activities developed in a large solar region during Carrington rotations, CRs 2119-2121, based on multiwavelength and multispacecraft observations. Three coronal holes (CHs), two transequatorial and one isolated, eight filaments and some active regions were distributed closely in …
The broad-band SEDs of four `hypervariable' AGN
Done, Chris; Elvis, Martin; Marshall, Philip J. +6 more
We present an optical-to-X-ray spectral analysis of four `hypervariable' AGN (HVAs) discovered by comparing Pan-STARRS data to that from the Sloan Digital Sky Survey over a 10 yr baseline (Lawrence et al.). There is some evidence that these objects are X-ray loud for their corresponding UV luminosities, but given that we measured them in a histori…
Searching for the lost Unicorn: a prominent feature in the radial velocity distribution of stars in Vela from Gaia DR2 data
de la Fuente Marcos, R.; de la Fuente Marcos, C.
Stellar streams are ubiquitous in the Galactic halo and they can be used to improve our understanding of the formation and evolution of the Milky Way as a whole. The so-called Monoceros Ring might have been the result of satellite accretion. Guglielmo et al. have used N-body simulations to search for the progenitor of this structure. Their analysi…
Variable interstellar absorption lines in young stellar aggregates
Krełowski, J.; Strobel, A.; Vješnica, S. +2 more
The variability of interstellar atomic lines, sporadically reported in the astronomical literature, has been confirmed both in the case of the nearby hot star δ Ori and the very young and violent star-forming region η Carinae, using high-resolution echelle spectra. The presented variability concerns the intensities and profiles of Na I, K I and Ca…
Modelling the diffuse dust emission around Orion
Shalima, P.; Gogoi, Rupjyoti; Saikia, Gautam
We have studied the diffuse radiation in the surroundings of M42 using photometric data from the Galaxy Evolution Explorer (GALEX) in the far-ultraviolet (FUV) and infrared observations of the AKARI space telescope. The main source of the FUV diffuse emission is the starlight from the Trapezium stars scattered by dust in front of the nebula. We in…