High level interfaces to the Robonet‐1.0 Homogeneous Telescope Network

We describe the current high level interfaces used for communicating with the Robonet‐1.0 Homogeneous Telescope Network. This is a network of three telescopes, the Liverpool Telescope and the Faulkes Telescopes (North and South). We describe our use of RTML and web‐services to enable control of the network by intelligent agents. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Charge‐exchange emission in the starburst galaxies M82 and NGC3256

Charge‐exchange (CE) emission produces features which are detectable with the current X‐ray instrumentation in the brightest near galaxies. We describe these aspects in the observed X‐ray spectra of the star forming galaxies M82 and NGC 3256, from the Suzaku and XMM‐Newton telescopes. Emission from both ions (O, C) and neutrals (Mg, Si) is recognised. We also describe how microcalorimeter instrumentation on future missions will improve CE observations (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The WASP project in the era of robotic telescope networks

We present the current status of the WASP project, a pair of wide angle photometric telescopes, individually called Super‐WASP. SuperWASP‐I is located in La Palma, and SuperWASP‐II at Sutherland in South Africa. SW‐I began operations in April 2004. SW‐II is expected to be operational in early 2006. Each SuperWASP instrument consists of up to 8 individual cameras using ultra‐wide field lenses backed by high‐quality passively cooled CCDs. Each camera covers 7.8 × 7.8 sq degrees of sky, for nearly 500 sq degrees of total sky coverage. One of the current aims of the WASP project is the search for extra‐solar planet transits with a focus on brighter stars in the magnitude range ∼8 to 13. Additionally, WASP will search for optical transients, track Near‐Earth Objects, and study many types of variable stars and extragalactic objects. The collaboration has developed a custom‐built reduction pipeline that achieves better than 1 percent photometric precision. We discuss future goals, which include: nightly on‐mountain reductions that could be used to automatically drive alerts via a small robotic telescope network, and possible roles of the WASP telescopes as providers in such a network. Additional technical details of the telescopes, data reduction, and consortium members and institutions can be found on the web site at: http://www.superwasp.org/. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Tomographic studies of exoplanet atmospheres

We review the current state of models for the optical and near‐infrared reflection spectra of exoplanetary atmospheres, with particular reference to the close‐orbiting giant planets that offer the best prospects for high‐resolution spectroscopic detection.We describe the main steps in the tomographic procedures that have been used in recent attempts to separate these faint signals from the direct spectra of the parent stars.We compare recent, deep upper limits on planetary albedos with model predictions, and discuss prospects for future attempts to detect and characterise the reflection, transmission and thermal emission spectra of these planets at optical and infrared wavelengths. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Differential rotation and meridional flow of Arcturus

The spectroscopic variability of Arcturus hints at cyclic activity cycle and differential rotation. This could provide a test of current theoretical models of solar and stellar dynamos. To examine the applicability of current models of the flux transport dynamo to Arcturus, we compute a mean‐field model for its internal rotation, meridional flow, and convective heat transport in the convective envelope. We then compare the conditions for dynamo action with those on the Sun. We find solar‐type surface rotation with about 1/10th of the shear found on the solar surface. The rotation rate increases monotonically with depth at all latitudes throughout the whole convection zone. In the lower part of the convection zone the horizontal shear vanishes and there is a strong radial gradient. The surface meridional flow has maximum speed of 170 m/s and is directed towards the equator at high and towards the poles at low latitudes. Turbulent magnetic diffusivity is of the order 10¹⁵–10¹⁶ cm²/s. The conditions on Arcturus are not favorable for a circulation‐dominated dynamo (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The merging/AGN connection: a case for 3D spectroscopy

We discuss an ongoing study of the connection between galaxy merging/interaction and AGN activity, based on integral field spectroscopy. We focus on the search for AGN ionization in the central regions of mergers, previously not classified as AGNs. We present here the science case, the current status of the project, and plans for future observations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The eSTAR network – agent architectures for astronomy

The eSTAR Project uses intelligent agent technologies to carry out resource discovery, submit observation requests and analyze the reduced data returned from a meta‐network of robotic telescopes. Linking ground based telescopes with astronomical satellites, and using the emerging field of intelligent agent architectures to provide crucial autonomous decision making in software, the project has succeeded in combining data archives and research class telescopes, along with distributed computing nodes, to build an ad‐hoc peer‐to‐peer heterogeneous network of resources. We present the current operations paradigm of the eSTAR network and describe the direction in which the project intends to develop over the next few years. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

GRB‐selected galaxies

We describe the current status and recent results from our Swift/VLT legacy survey, a VLT Large Programme aimed at characterizing the host galaxies of a homogeneously selected sub‐sample of Swift gamma‐ray bursts (GRBs). The immediate goals are to determine the host luminosity function, study the effects of reddening, determine the fraction of Lyα emitters in the hosts, and obtain redshifts for targets without a reported one. We have defined a very carefully selected sample, obeying strict and well‐defined criteria: 68 targets in total. Among the preliminary results is a large optical detection rate, the lack of extremely red objects (only one possible case in the sample), and 10 new GRB redshifts with the mean redshift of the host sample assessed to be 〈z 〉 ≳ 2 (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

E3D,the Euro3D visualization tool I: Description of the program and its capabilities

We present the first version of E3D, the Euro3D visualization tool for data from integral field spectroscopy. We describe its major characteristics, based on the proposed requirements, the current state of the project, and some planned future upgrades. We show examples of its use and capabilities. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope

We check the performance of the FRODOSpec integral‐field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic‐ray events, scattered‐light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non‐standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral‐field spectrographs on current and future robotic telescopes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A synoptic program for large solar telescopes: Cyclic variation of turbulent magnetic fields

Upcoming large solar telescopes will offer the possibility of unprecedented high resolution observations. However, during periods of non‐ideal seeing such measurements are impossible and alternative programs should be considered to best use the available observing time. We present a synoptic program, currently carried out at the Istituto Ricerche Solari Locarno (IRSOL), to monitor turbulent magnetic fields employing the differential Hanle effect in atomic and molecular lines. This program can be easily adapted for the use at large telescopes exploring new science goals, nowadays impossible to achieve with smaller telescopes. The current, interesting scientific results prove that such programs are worthwhile to be continued and expanded in the future. We calculate the approximately achievable spatial resolution at a large telescope like ATST for polarimetric measurements with a noise level below 5 × 10^‐5 and a temporal resolution which is sufficient to explore variations on the granular scale. We show that it would be important to optimize the system for maximal photon throughput and to install a high‐speed camera system to be able to study turbulent magnetic fields with unprecedented accuracy (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

X‐ray energy spectra of CAL87

We present X‐ray spectral analysis of the super‐soft source CAL87 using ASCA, Chandra, XMM‐Newton observations. Early ASCA CCD spectrum reported a strong oxygen absorption edge, which is considered to originate in the an optically thick white‐dwarf atmosphere. On the other hand, contemporaneous grating observations by Chandra and XMM‐Newton indicate emission line dominated spectra, which obviously indicate the optically thin origin. Fitting all the available CCD (ASCA and XMM‐Newton) and grating spectra (XMM‐Newton and Chandra) simultaneously, we show that the CAL87 X‐ray energy spectrum is in fact composed of both an optically thick component with deep absorption edges and an optically thin component with numerous emission lines. The current result supports the standard SSS model that the primary source of X‐ray emission is nuclear burning in the white dwarf atmosphere, surrounded by a highly photoionised, optically thin corona (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Geometric characterization of the Arjuna orbital domain

Arjuna‐type orbits are characterized by being Earth‐like, having both low‐eccentricity and low‐inclination. Objects following these trajectories experience repeated trappings in the 1:1 commensurability with the Earth and can become temporary Trojans, horseshoe librators, quasi‐satellites, and even transient natural satellites. Here, we review what we know about this peculiar dynamical group and use a Monte Carlo simulation to characterize geometrically the Arjuna orbital domain, studying its visibility both from the ground and with the European Space Agency Gaia spacecraft. The visibility analysis from the ground together with the discovery circumstances of known objects are used as proxies to estimate the current size of this population. The impact cross‐section of the Earth for minor bodies in this resonant group is also investigated. We find that, for ground‐based observations, the solar elongation at perigee of nearly half of these objects is less than 90°. They are best observed by space‐borne telescopes, but Gaia is not going to improve significantly the current discovery rate for members of this class. Our results suggest that the size of this population may have been underestimated by current models. On the other hand, their intrinsically low encounter velocities with the Earth induce a 10–1000‐fold increase in the impact cross‐section with respect to what is typical for objects in the Apollo or Aten asteroid populations. We estimate that their probability of capture as transient natural satellites of our planet is about 8 %. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A SAURON look at galaxy bulges

Kinematic and population studies show that bulges are generally rotationally flattened systems similar to lowluminosity ellipticals. However, observations with state‐of‐the‐art integral field spectrographs, such as SAURON, indicate that the situation is much more complex, and allow us to investigate phenomena such as triaxiality, kinematic decoupling and population substructure, and to study their connection to current formation and evolution scenarios for bulges of early‐type galaxies. We present the examples of two S0 bulges from galaxies in our sample of nearby galaxies: one that shows all the properties expected from classical bulges (NGC5866), and another case that presents kinematic features appropriate for barred disk galaxies (NGC7332). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Big Bear Solar Observatory Ca II K‐line index for solar cycle 23

We present an analysis of 2634 Ca II K‐line full‐disk filtergrams obtained with the 15‐cm aperture photometric full‐disk telescope at Big Bear Solar Observatory during the period from 1996 January 1 to 2005 October 24. Using limb darkening corrected and contrast enhanced filtergrams, solar activity indices were derived, which are sensitive to the 11‐year solar activity cycle and 27‐day rotational period of plages around active regions and the bright chromospheric network. The present work extends an earlier study (solar cycle 22), which was based on video data. The current digital data are of much improved quality with higher spatial resolution and a narrower passband ameliorating photometric accuracy. The time series of chromospheric activity indices cover most of solar cycle 23. One of the most conspicuous features of the Ca II K indices is the secondary maximum in late 2001/early 2002 after an initial decline of chromospheric activity during the first half of 2001. We conclude that a secular trend exists in the Ca II K indices, which has its origin in the bright chromospheric network and brightenings related to decaying active regions. Superposed on this secular trend are the signatures of recurring, long‐lived active regions, which are clusters of persistent and continuously emerging magnetic flux. Such features are less visible, when the activity belts on both side of the equator are devoid of the brightenings related to decaying active regions as was the case in October/November 2003 at a time when a superactivity complex including several naked‐eye sunspots emerged (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Architectures for science: Intelligent agent technology

I review the current architecture of the HTN and make three suggestions for the future. (i) We should retain the expertise split between agents which deal with the science programmes and those which deal with telescope constraints. This makes it easy to add new programmes or new telescopes. (ii) We should develop “look ahead” schedulers which attempt to schedule a whole night at once. This will give reliable calculations for the chance an observation will be carried out, and give a better chance that high priority time critical observations are successfully scheduled. (iii)We should strive to attract more science programmes to the HTN, in particular time critical observations spread over many nights, and non‐time critical work which can benefit from access to databases and the literature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Observational characteristics of dense cores with deeply embedded young protostars

Class 0 objects, which are thought to be the youngest protostars, are identified in terms of NIR or radio emission and/or the presence of molecular outflows. We present combined hydrodynamic and radiative transfer simulations of the collapse of a star‐forming molecular core, which suggest two criteria for identifying dense cores with deeply embedded very young protostars that may not be observable in the NIR or radio with current telescopes. We find that cores with protostars are relatively warm (T > 15 K) with their SEDs peaking at wavelengths <170 µm, and they tend to appear circular. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Chemical spots and oscillatory diffusion modes in magnetic stars

The stars of the middle main sequence often have spot‐like chemical structures at their surfaces. We consider diffusion caused by electric currents and argue that such current‐driven diffusion can form chemical inhomogeneities in a plasma. The considered mechanism can contribute to a formation of element spots in Hg‐Mn and Ap‐stars. Due to the Hall effect, diffusion in the presence of electric currents can be accompanied by the propagation of a particular type of magnetohydrodynamic modes in which only the impurity number density oscillates. Such modes exist if the magnetic pressure is much greater than the gas pressure and can be the reason for variations of the abundance peculiarities in stars. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Magnetic and velocity fields of active regions

We have observed about 15 active regions on the Sun, with the Advanced Stokes Polarimeter and Dick Dunn Telescope at NSO/SP to map the Stokes parameters in the photospheric Fe 6302.5 Å and chromospheric Mg I 5173 Å lines, during 1999‐2002. The observations are corrected for dark current, gain, instrumental polarization and cross‐talk using ASP pipeline. The wavelength calibration is carried out using the O₂ telluric line 6302 Å which is also present in the observations. The photospheric and chromospheric longitudinal magnetograms are made from the Stokes V profiles, which were intercalibrated with the Kitt Peak magnetograms. The plasma motions are inferred from the line bisector measurements at different positions of the spectral line. In this paper we present the height dependence of Doppler velocity scatter plots of a sunspot in the photospheric Fe I 6302 Å line.     

On the ephemeris of the eclipsing polar HU Aquarii

The magnetic cataclysmic variable HU Aquarii displayed pronounced quasi‐periodic modulations of its eclipse timing. These were interpreted in terms of the light‐travel time (LTT) effect caused by a circumbinary planet or planetary system. We report new photometric observations that revealed another precise eclipse timing for the October 2013 epoch, the first obtained in a high accretion state after many years in low or intermediate states. The eclipse was observed to occur earlier by 95.3 ± 2.0 s or 62.8 ± 2.0 s than expected for an assumed linear or quadratic ephemeris, respectively. The implied apparent strong evolution of the orbital period calls for a revision of the current planetary model or the planetary parameters. The object deserves further monitoring to uncover the true nature of the observed variability and to constrain the properties of the proposed planet or planetary system. The new observations prove that advanced amateur equipment can successfully be used in the growing field of planet search in wide circumbinary orbits via the LTT effect. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)