Are you the publisher? Claim or contact us about this channel


Embed this content in your HTML

Search

Report adult content:

click to rate:

Account: (login)

More Channels


Channel Catalog


Channel Description:

A daily view of all the goings-on at ASTRON and JIVE.

older | 1 | .... | 36 | 37 | (Page 38) | 39 | 40 | .... | 71 | newer

    0 0

    © ASTRON/CAMRAS

    Between 2012 and 2014, the Dwingeloo Radio Telescope (DRT) was restored. Jan Klaassens, Hilko Hof and Arie Burggraaf from amateur video club Spotlight in Hoogeveen made a documentary about this restoration, including the reopening on April 5th 2014 by astrophysicist, radio amateur en Nobel Prize laureate Joe Taylor.

    Today (friday, April 15th) at 15.00 we will have the premiere of this documentary in the Van de Hulst Auditorium at ASTRON. The image above is its YouTube trailer(*). Everybody is invited to attend this event. Not surprisingly the premiere almost coincides with the 60th anniversary of the Dwingeloo Radio Telescope. It was officially opened by Queen Juliana on April 17th 1956.

    The film is available on DVD and costs 20 Euro. The DVD contains the documentary and an appendix which shows all the steps of the restoration in more detail. The 1957 movie of Herman Kleibrink about the construction of the Dwingeloo Radio Telescope is also on this DVD. You can order it via info@camras.nl.

    (*) Unfortunately, the Youtube trailer doe not repeat automatically, for some reason. But of course you can view it as often as you like on your own computer.


    0 0

    © R&D

    The Big Data collaboration between ASTRON and IBM is now getting to a point where not only fundamental research, but also applied research is key to realize the Square Kilometre Array (SKA). The picture shows Gert Kruithof of ASTRON and four participants in the Dome Users Platform after signing a new agreement for Collaboration on Big Data for Radio Astronomy (COBRA).

    This collaboration benefits astronomical science, the SKA project, ASTRON and the Big Data industry in the Netherlands.

    The amount of data produced by the SKA telescope is huge, and requires new approaches. The four COBRA partners KxA Innovation Solutions, MMPBI, S&T and TriOpSys are all established in the (Northern) Netherlands and have knowledge of handling Big Data. Together with ASTRON they can build a Science Data Centre (SDC) to determine the most efficient data processes with the aim to analyze data much faster and easier. This is a major step towards gaining more knowledge of the universe. It also means an acceleration in the progress of science in the Netherlands in this area.

    The signing of the COBRA agreement took place at the scientific Dome event Sensors, Signals and Smart Systems at ASTRON on April 13th. About 60 people attended this event, which also sported a show-case market.


    0 0

    © ??

    After a long battle with cancer Kurt Weiler passed away at the age of 74 on 17 April, 2016. Kurt was the first Telescope Astronomer of the Westerbork Synthesis Radio Telescope, he worked for ASTRON from 1970 to 1974. He was young, not a man of many words, but very well-liked and very knowledgeable.

    His greatest contribution to the WSRT was the careful analysis and calibration of the polarisation properties of the original frontends, which correlated "crossed" dipole sets from separate telescopes, i.e. in the case of the WSRT dipoles that were at 90 degrees angle in each telescope, but at 45 degrees angle between telescopes. See K.W. Weiler, The Synthesis Radio Telescope at Westerbork. Methods of Polarization Measurement A&A, Vol. 26, p. 403 (1973). Because of its design, the WSRT is still the best radio telescope in the world for polarisation measurements.

    After his WSRT period, Kurt was with the Max-Planck-Institut fur Radioastronomie in Bonn from 1976 to 1979. He returned to his native USA to work at the National Science Foundation (NSF), and then at the Naval Research Laboratory (NRL). His major interest was in Supernovae, for which he was editor of the book on Supernovae and Gamma-Ray Bursters (Springer 2003).

    In the meantime he continued to interact with ASTRON in various ways. In 1997 he was short-listed for the function of Head of the Telescope Group, and while at USNO he was briefly involved in the LOFAR Consortium. In addition, he was active in several other fields that were also of interest to ASTRON, like optical interferometry from the ground (BOA) and the observation of (very) low frequency radio waves (1-10MHz) from space.

    Kurt is survived by his (Dutch) wife Geertje and their three children. A memorial service will be held in the Netherlands at a later date.


    0 0
  • 04/26/16--17:00: Kids Universe
  • © JvL

    Editor's note: Today is King's Day, the official birthday of our gracious King Willem Alexander. This Daily Image has been specially selected because its subjects are close to the heart of the Royal Couple.

    Because astronomy is highly visual and thought-provoking, it is uniquely suited to engage young students, girls and boys alike, in the physical sciences. The Universe is right above us to observe and think about, and our images are some of the most awe-inspiring out there.

    In a series of lectures for kids, we try to bring across this excitement. Pictured above is a show in which a few hundred kids were actively engaged -- going clock wise from the top left: warming up with Klokhuis astronaut presenter Maurice Lede; a session where the "Law of Gravity" is temporarily suspended and all kids float in their seats, until after a loud countdown it is reinstated and everyone crashes back to Earth; a hat-on hat-off show with ten questions and a good prize for the winner; and a demo where a polar bear and a penguin argue they are both "up" and the other is "down", where the loudest supporting half of the audience wins. Spoiler -- they're both up :).


    0 0

    © ASTRON, 2016

    Great progress in APERTIF: On April 1st, all hardware for both polarisations was installed at three WSRT dishes!

    It the first time at ASTRON that a complete dual-pol phased array feed (PAF) is connected to a backend!

    We installed the extra beamformer for the second (Y) polarisation in the container of three telescopes (left image). By doing so, all 121 antennas in the PAF frontend (upper right image) are connected to the full dual-pol backend. The bottom right figure shows the measured power over frequency of all antennas.

    Until now, all measurements were done with only the X polarisation antennas (signal input number 0 to 63). From now on, both X and Y polarised antennas can be used. This makes it possible to do new kind of measurements (e.g. polarisation properties), required for APERTIF technical commissioning, and APERTIF science.


    0 0

    © Courtesy FAST team of the NAOC

    The Five-hundred-meter Aperture Spherical Telescope (FAST) in China is rapidly approaching its completion, when all 4600 panels will have been fitted onto the underlying cable network. (see AJIoD 31-10-2006, 18-06-2007, 02-10-2013, 27-10-2014).

    The FAST proposal started as the Chinese proposal for the SKA, and could be seen as one of its early precursors. It supersedes the 300m Arecibo telescope as the largest single dish radio telescope in the world.

    The photo shows the status in late February, when Leonid Gurvits visited the site with Prof Nan Rendong, the FAST instigator and general leader (and an old friend of ASTRON and JIVE).

    The frontend receiver box will have the size of a decent bus, and will be suspended above the telescope by means of cables from the 6 towers, each of which is more than 200m high! By adjusting the cables, the box may be moved to the optimal position for viewing in a particular direction. At the same time, the panels of the huge surface will be adjusted to form the ideal parabolic surface for that direction.

    The control building is off the right of the photograph.


    0 0

    © Picture: Jan-Olof Yxell,Chalmers University of Technology

    While at a recent conference, our good friend Per-Simon Kildal suffered a major haemorrhage and passed away at the age of 64 on Thursday 21 April, 2016.

    He was a long-time professor at Chalmers University (Sweden), and played a large role in its close relationship with ASTRON. Apart from collaborating in the research and development of antennas (e.g. for SKA), Chalmers also became the home of our very own Marianna Ivashina and Rob Maaskant. And as a result of my own joint appointment, several Chalmers students continued their education at ASTRON and Groningen. I fondly remember his contribution to the workshop at the occasion of my ASTRON retirement.

    Per-Simon is probably best known to the radio astronomy community for his research of the so-called "eleven" feed, a main contender for wideband single-pixel feeds for the Square Kilometre Array dishes. This work was performed in close connection with the Onsala Space Observatory, and was supported also by the SKA and national Swedish grants. In addition, he designed the feed system for the 300 Arecibo dish, feeds for OSO, and the wideband antenna for VLBI2010.

    As an incredibly positive, dynamic and broadly oriented person, he wrote hundreds of publications, published two books on antennas and feeds, and stood at the basis of several companies, valorising patents of antenna designs.

    Per-Simon's diverse and many fruits cannot be reaped anymore, neither by him nor by his family. But our memories and his many professional contributions will last.


    0 0

    © Foreground images: S.M. Straal, K.E. Gabanyi. Background images: NASA/NRAO/HST

    One of the main goals of observers is to identify the objects in the sky such that they can better understand their nature. Sometimes it is not so straight forward to identify an object, its properties may indicate very different natures. In that case we come up with the big guns and try every possible observational approach to get to know more about the object.

    HESS J1943+213 is an unidentified TeV source that is likely a high-frequency-peaked BL Lac (HBL) object but also compatible with a pulsar wind nebula (PWN) nature. Each of these enormously different astronomical interpretations is supported by some of the observed unusual characteristics. In order to finally classify and understand this object we took a three-pronged approach, through time-domain, high angular resolution, and multi-frequency radio studies.

    Our deep time-domain observations with the Arecibo telescope failed to uncover the putative pulsar powering the proposed PWN. We conclude with ~70% certainty that HESS J1943+213 does not host a pulsar. Using radio observations that probe different angular scales we find that the source consists of a compact core and an extended structure, while for PWNe a single component is expected. Moreover, investigating the obtained radio flux density at similar wavelengths and angular scales, we find that its 2013 flux density is about one-third lower than detected in 2011 observations with similar resolution. This radio variability of the core strengthens the HBL object hypothesis.

    Overall, we rule out the PWN hypothesis and conclude the source is a BL Lac object. The consistently high fraction (70%) of the flux density from the extended structure then leads us to conclude that HESS J1943+213 must be a non-classical HBL object.

    In the image you can see on the background (left) an artist impression of an active galaxy, of which BL Lac objects are a subclass. The other background image shows the famous Crab nebula, which is a combined supernova remnant, PWN. The top figure shows the different angular scales our radio observations probed where the extended structure is over-plotted in the left top graph. The bottom panels show the observed e-MERLIN compact core at 1.5 (left) and 5 GHz (right).

    The results are presented in ApJ (in print) by Samayra Straal, Krisztina Gabanyi, Joeri van Leeuwen, Zsolt Paragi and other collaborators and can be found here: http://arxiv.org/abs/1603.01226


    0 0

    © Jeanette Bast, Roy Smits

    ARTS will, together with Apertif (APERture Tile In Focus), extend the instantaneous field of view of the Westerbork telescopes by a factor of 37. This wide field of view will make the telescopes very sensitive to detecting rare radio bursts, such as RRATS (Rotating RAdio Transients) and FRBs (Fast Radio Bursts).

    ARTS (Apertif Radio Transient System) is the advanced backend to Apertif. It is designed specifically to allow for deep searches of pulsars, and to optimize the detection of FRBs. This requires handling (very) high data-rates and the capability for different modes of observation. ARTS has now reached one of its important milestones where the beamformer and the pipeline for high precision pulsar timing for the first time 'communicate' with each other.

    The images show the first hardware of ARTS that is under commissioning. The machine is called ARTS-0 and has the high precision pulsar timing pipeline implemented on it. This is capable of performing real-time coherent dedispersion of radio pulsars. It is fed beam-formed data from a UniBoard, for which the FPGA firmware was largely re-used from the Apertif beamformer. The graph shows the folded profile of a fake pulsar signal that traveled from the beamformer through the entire pipeline.


    0 0

    © Astron/JIVE

    Earlier this year, Keane et al. (2016) announced the discovery and accurate localization of a rare type of transient signal called a Fast Radio Burst (FRB), that lasts only for a few milliseconds. The origin of FRBs is not clear yet, but they are likely located at great distances from us, at least in neighbouring galaxies or even further away. Keane et al. have developed a real-time transient detection system at Parkes Observatory, and detected FRB 150418 last year. Surveying the area with the Australia Telescope Compact Array (ATCA) revealed an 'afterglow' signal that faded away in 6 days. This variable source was located in a galaxy at a redshift of z=0.492. If the FRB and the fading radio source seen by ATCA are related, this means that at least some of the FRBs are truly cosmological (see AJDI 20160226 by Emily Petroff).

    There were, however, claims that the two events are not related. According to Williams & Berger (2016), Very Large Array (VLA) monitoring results show that there is a highly variable radio source in the centre of the claimed host galaxy of FRB 150418, a source that they interpret as an active galactic nucleus (AGN). The short timescale variability implies that the AGN must be very compact.

    To probe the nuclear radio emission of the proposed host galaxy, we carried out very long baseline interferometer (VLBI) observations with the e-EVN at 5 GHz, on 2016 March 16. These data confirm a nuclear radio source compact on milliarcsecond scales in the host galaxy WISE J071634.59-190039.2, and therefore the existence of an AGN. The peak brightness of the emission was just 127 microJy/beam, consistent with other high resolution observations. Further observations with the EVN are planned, and a comparison with other projects carried out with VLA, ATCA, VLBA, and e-MERLIN, is expected to clarify important details about the nature of this radio source, and in particular its association with the FRB. The results were reported by Marcote et al. in ATel #8959. The e-EVN image above was provided by Marcello Giroletti (INAF).


    0 0
  • 05/05/16--17:00: Drone measurements on LOFAR
  • © ASTRON

    From Monday, April 18 until Thursday, April 21, measurements have been done on LOFAR station CS302 to collect reliable data on the response of the individual antennas within a LOFAR station using a drone developed within a collaboration between INAF, CNR-IEIIT and the Politecnico di Torino (PT). This drone, a hexacopter, is shown in action in the bottom left panel. It carries a variable-length dipole allowing to illuminate the antenna(s) under test with a (comb of) CW signal(s) in a well-defined linear polarization.

    The team conducting these measurements is shown in the top left panel and consisted of (front row, then rear row) Fabio Paonessa (CNR-IEIIT), Paolo Maschio (PT), Andrea Lingua (PT), Giuseppe Pupillo (INAF), Menno Norden (ASTRON), Stefan Wijnholds (ASTRON), Giuseppe Virone (CNR-IEIIT), Pietro Bolli (INAF) and Irene Aicardi (PT).

    We managed to exploit the flexibility of both the LOFAR system and the probe to conduct measurements at up to four different frequencies simultaneously. Besides linear scans, we also conducted a number of spin flights in which the hexacopter is kept in a stationary position while spinning around its own axis.

    Spin flights allow us to very accurately measure the polarization performance of the antenna since all possible angles are scanned. As a result, optimal alignment with both the cross-polarization and the co-polarization of the antenna is achieved at some point during the spin flight. This is illustrated by the curves shown in the right panel showing the output power of the x- and y-dipole of the central low-band antenna at 44.5 MHz during a spin flight in which the hexacopter made two full spins around its axis revolving in opposite directions. The curves clearly show how the signal transmitted by the hexacopter is first matched to the x-polarization, then to the y-polarization, and so on. From these measurements, we can conclude that the orthogonality between the two dipoles of the central element is very good towards zenith with cross-polarization levels as low a -40 dB compared to the co-polarization levels.

    We are currently reducing the data to allow a comparison with a number of EM models. This is ultimately expected to lead to an accurate EM model of a LOFAR station, which can then be used to accurately predict the direction dependent response of the station. We also want to assess whether it is possible to determine the antenna positions using such measurements. Such a procedure could greatly simplify the roll-out of SKA-low.


    0 0

    © R.H. van den Brink

    Everybody knows, 'vele handen maken licht werk'! This was the thought for APERTIF when all optical fibers for the beamformers and the correlator turned out to have a request for labelling.

    A onetime action that needs to be done in a short period of time, but will drain all motivation out of a person when doing it alone. APERTIF got assistance of several (temporary) ASTRON people to get the job successfully done.

    Sjouke Zwier nicely prepared the action by setting up the Muller Room for a few hours and transformed it into a good oiled assembly line. After an instruction of the procedure, ten people were good to go. The result is an organized set of optical fibers sorted per dish, ready for installation at Westerbork.

    The picture shows Martijn Kamps, Sjouke Kuindersma, Eim Mulder, Tom Houtsma, Sieds Damstra, Sjouke Zwier, Mark Dekens, Renze Prochazka and Elfi Dijkstra.


    0 0

    © Credits: NASA/DOE/LAT Collaboration (top panel), TANAMI (bottom panel)

    Blazars are among the most energetic objects in the extragalactic sky. These active galaxies host powerful, relativistic jets that are pointed close to the line of sight of the observer emitting strongly from the radio to the gamma-ray regime. Blazars are also considered to be able to produce neutrinos, fundamental particles that are very difficult to detect. Recently, the IceCube collaboration reported the detection of neutrinos which might have an extraterrestrial origin.

    The above images show the blazar PKS B1424-418 in different energy regimes between 2011 and 2013. The gamma-ray images (top panel) were obtained with the Fermi Gamma-ray Space Observatory catching the source (in the center of the images) during a very strong outburst. The radio VLBI images (bottom panel) were taken over the same time frame as part of the multiwavelength programme TANAMI which monitors about a 100 active galaxies in the southern hemisphere. The array used by TANAMI comprises the Australian Long Baseline Array and associated telescopes in Chile, South Africa, New Zealand and Antarctica providing very high angular resolution down to about 1 milliarcsecond which corresponds to about 30 light-years for this source. The outburst exhibited by PKS B1424-418 in the radio is the strongest within the TANAMI sample so far.

    Intriguingly, the position and the time of the outburst of PKS B1424-418 coincides with the detection of a 2PeV neutrino by the IceCube collaboration (dashed line in the top panel). The energy emitted by PKS B1424-418 across the electromagnetic spectrum is sufficient to produce such a very high-energy neutrino. The study that is published in Nature Physics ("Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event", Kadler et al. 2016) suggests that these events are linked.


    0 0

    © MA3 Solutions, ASTRON and Ghent University

    In the past years, the company MA3 Solutions at Son (Eindhoven, NL) has developed a unique and novel technique for connecting a large number of optical fibers to a Silicon Photonics integrated circuit. To investigating and demonstrate this fibre-chip coupling technique, a 4-channel switched (optical fibre based) delay line demonstrator has been developed in a collaboration between ASTRON, MA3 and Ghent University.

    In this collaboration, MA3 has realised a fibre-chip coupler with more than 40 single-mode optical fibers for establishing optical connections to 4 rows of optical switches on a Silicon Photonics chip. The latter was designed and fabricated by the Photonics Research Group at Ghent (Belgium) within the framework of the ACTPHAST project (www.actphast.eu). All system construction related aspects like fibre splicing, wirebonding, design and fabrication of control electronics and fabrication of a mechanical support structure were handled by ASTRON.

    Currently, the fabrication and initial characterisation of two demonstrator systems are finalised. For showing the potential of the novel fibre-chip connection technology to a greater audience, the demonstrator was displayed in the ACTPHAST booth at the Hannover Messe. In the coming time the possible use of the MA3 technology in radio astronomy systems like the SKA/MFAA will be investigated in a DOME Users Platform study.


    0 0

    © Paola Pinilla

    Transition disks are protoplanetary disks with inner dust cavities and they may reveal an intermediate step of the ongoing disk dispersal process, where planet formation might happen. The recent gas and dust observations of transition disks have given major support to the idea that clearing by planet(s) is the primary cause for the origin of the cavities in transition disks.

    In this talk I will present gas and dust evolution models of transition disks, and I will show the different structures that disks can have (rings, vortices, spiral arms) when a planet or multiple planets are embedded in the disk. Moreover, I will connect these results with recent SPHERE/VLT and ALMA observations of some of these disks, e.g. J160421, HD 100546, SR 21, and HD 135344B.


    0 0
  • 05/12/16--17:00: UK-NL cooperation
  • © Fotobureau 't Sticht BV

    In the eighties of the last century the cooperation between the Dutch Research Organisation (NWO, previous ZWO) and its British counterpart (SERC, previous SRC, now STFC) was quite strong in the area of physical sciences.

  • In astronomy they partnered in optical telescopes on the Canary Islands, and in infrared and sub-mm telescopes on Mauna Kea (on Hawaii).

  • In physics and chemistry there was, among others, the cooperation between SERC and FOM/NWO on the British use of the free-electron laser (FELIX, Rijnhuizen), and between SERC and NWO on the Dutch use of the Synchrotron Radiation Source (SRS, Daresbury).

    During this period there were regular Umbrella meetings between the parties, which took place in The Netherlands and in the United Kingdom alternatively. The photograph shows the one held in the second half of 1989 in the Alexander room of the Rijnhuizen Castle in Nieuwegein (note the gobelin with a scene of the short life of Alexander the Great in the background). In this castle the FOM Institute for Plasma physics (now DIFFER: Dutch Institute For Fundamental Energy Research) was housed at that time (now at Eindhoven University of Technology, and FELIX at Radboud University).

    The photograph depicts the signing of the agreement between NWO/FOM and SERC about the use of FELIX by SERC.

  • In the front from left to right: Head SERC administration, Sir Bill Mitchell (SERC-chair), Jan Borgman (NWO-chair), Henk van der Molen (NWO-director).

  • In the back from left to right: Yehudi Levine (Utrecht University, Synchrotron Radiation), Chief Financial Officer (SERC), Tony Hughes (SERC), Barry Martin (SERC-director), Vince Osgood (SERC), Wim Brouw (ASTRON), Hette Weijma (NWO).


  • 0 0

    © Astron

    After 3 years, the UniBoard2 project (a part of the Radio Net FP7 programme) has been succesfully completed. With the shipment of the UniBoard2s to the partners in the project, the work of ASTRON and JIVE ERIC is done.

    A total of 7 state-of-the-art computing platforms have been created, tested and integrated. The boards, complete with firmware, manual, liquid cooling and cables, are ready to be used by the 7 partner institutes in the RadioNet project:

  • Max-Planck-Institut fuer Radioastronomie Bonn - Germany

  • Universite de Bordeaux - France

  • INAF Osservatorio Astrofisico di Arcetri - Firenze Italy

  • University of Manchester - United Kingdom

  • Laboratoire PRISME -- Station de Radioastronomie de Nancay - France

  • ASTRON

  • JIVE -ERIC


  • 0 0
  • 05/16/16--17:00: A star is born!
  • © ASTRON

    One of the goals of the RadioLife ERC project is to understand the influence a radio jet has when passing through the surrounding gas. If one thinks about this process, it is quite natural to imagine that the jet would push aside all the gas and there is no gas left to form stars from. This is indeed one of the effects often observed (see for example Daily Image 26-01-2016 or 18-08-2015). However, surprisingly also the opposite can happen: the jet compresses the gas so much that star formation may start. Thus a "constructive" encounter may happen instead of only a "destructive" one!

    We have used the Multi-Unit Spectroscopic Explorer (MUSE) on the ESO-VLT to discover a region where such an effect is happening: a newly born star in a filament of gas near the closest radio galaxy and active nucleus, Centaurus A, and we have studied this in detail.

    The picture on the left shows the region of the so-called outer filament of Centaurus A as observed by MUSE (see also the Daily Image of 17-02-2015) and on the right how the conditions of the gas change across the region. Red regions indicate gas affected only by the radiation from the active nucleus, but purple shows the locations where the conditions in the gas are determined by the radiation from a newly-born star. In places in between a mixture of these two ionization mechanisms are operating. Thus, in addition to allow to study the process of star formation under the influence of an active nucleus, these results emphasize the complexity of this process. This is important if we want to be able to identify this process in objects that are much more distant (where we cannot see all the details). The results also illustrate that these young stars influence the gas over only a limited region, answering one of the main open questions about this process.

    The results are presented in the paper:

    "Embedded star formation in the extended narrow line region of Centaurus A: extreme mixing observed by MUSE", by Francesco Santoro; Raymond Oonk, Raffaella Morganti, Tom Oosterloo, Clive Tadhunter, published in Astronomy & Astrophysics (http://arxiv.org/abs/1604.03891 ).


    0 0

    © PNSC

    For most of our followers, it is not a surprise that Poland recently joined the LOFAR family with three stations. A fact much less emphasised is that as a part of this collaboration, the Poznan supercompute centre (also know as the PSNC) joined the illustrious group of institutes hosting a part of the LOFAR Long-Term Archive.

    During the last working days of December 2015 and the first months of 2016, both ASTRON and PSNC worked hard to ensure that the infrastructure would be in place for production use. This culminated in the first production ingest on 11th March 2016. We look forward to continuing the collaboration with our Polish partners in the future.

    The image shows the tape library used by the PSNC to store the LOFAR data.

    As telescope builders, we are used to celebrating first-light events. With our increased ambitions in astronomy data management, we should also get used to celebrate first-byte.

    This achievement has been a group effort. We owe our gratitude to many. The following people were most involved (in no particular order):

  • Gracjan Jankowski (PSNC)

  • Maciej Brzezniak (PSNC)

  • Slawomir Zdanowski (PSNC)

  • Ron Trompert (SurfSARA)

  • Cristina Manzano (FZJ)

  • Olaf Wucknitz (FZJ)

  • Jorrit Schaap (ASTRON)

  • Yan Grange (ASTRON)

  • Hanno Holties (ASTRON)

  • Science support (ASTRON)

  • 0 0

    © Andrew Shearer

    Optical pulsar studies are the poor relation of radio observations primarily due to their faintness and consequent difficulty in obtaining basic data beyond basic photometry. Over the next decade this change with larger optical telescopes and higher throughput instrumentation.

    This talk will review the current state of optical polarisation measurements of pulsars concentrating on multi-wavelength observations of the Crab pulsar which is bright enough for both spectroscopy and polarimetry. Until recently the Crab nebula was regarded as a high-energy standard candle but observations of strong flares changed that perspective. The location of the flares and any association with the central pulsar is not understood. Recent joint optical - Gamma-ray observations [Moran et al, 20016, MNRAS, 456, 297] with Integral and the Galway Astronomical Stokes Polarimeter (GASP) indicates possible variability in the optical polarisation from the region around the Crab pulsar. Is this associated with the flaring activity? Phase resolved optical polarisation measurements also offer the possibility of mapping the emissions zones with a pulsar’s magnetosphere, first results and pitfalls of this will also be presented.

    Finally, future possibilities with SKA, XIPE and Micado/E-ELT will be explored.


older | 1 | .... | 36 | 37 | (Page 38) | 39 | 40 | .... | 71 | newer