Pulsar observations with the Effelsberg LOFAR station Masaya Kuniyoshi Max Planck Institute for Radio Astronomy on be half of MKSP/PWG Friday, June 7, 13
Who are you? • ~2007 : Waseda University in Japan • 2007~2009 : LWA in the U.S. • 2009~Present : LOFAR in Germany Friday, June 7, 13
Who are you? • ~2007 : Waseda University in Japan • 2007~2009 : LWA in the U.S. • 2009~Present : LOFAR in Germany Friday, June 7, 13
Who are you? • 2007~2009 : LWA in the U.S. Friday, June 7, 13
Who are you? • 2007~2009 : LWA in the U.S. VLA VLA LWA V L A Friday, June 7, 13
Who are you? • 2009~Present : LOFAR in Germany Friday, June 7, 13
Who are you? • 2009~Present : LOFAR in Germany Pulse number ! Pulse phase ! Friday, June 7, 13
Outline • Effelsberg LOFAR station • Pulsar Observations • Jones Matrix calibrations • Public Outreach Friday, June 7, 13
The LOw Frequency ARray (LOFAR) Friday, June 7, 13
The LOw Frequency ARray (LOFAR) • A pathfinder to the SKA • Operation in the frequency from 10 to 240 MHz • An international telescope • Eight international stations and more down the road Humbug in Germany, three stations in Poland. Friday, June 7, 13
The LOFAR stations Friday, June 7, 13
The LOFAR stations Cosmic Magnetism Cosmic Rays Epoch of Reionization Extragalactic Surveys Solar Physics Transients The core is heavily subscribed! Many projects only require short baselines, leaving the international LOFAR stations unused. Friday, June 7, 13
The LOFAR stations The core is heavily subscribed! Cosmic Magnetism Many projects only require short Cosmic Rays baselines, leaving the international Epoch of Reionization LOFAR stations unused. Extragalactic Surveys Solar Physics Transients Friday, June 7, 13
The LOFAR stations The core is heavily subscribed! Cosmic Magnetism Many projects only require short Cosmic Rays baselines, leaving the international Epoch of Reionization LOFAR stations unused. Extragalactic Surveys Solar Physics Transients Friday, June 7, 13
Effelsberg LOFAR Station (DE601) The first LOFAR station outside the Netherlands Friday, June 7, 13
Stand-Alone mode HBA LBA LBA dipole HBA tile Beamforming Recording & Processing A pulsar profile Friday, June 7, 13
Friday, June 7, 13
Pulsars • Rapidly rotating highly magnetized neutron stars • Weighing more than our Sun, yet only 20 km in diameter, these incredibly dense objects produce radio beams that sweep the sky like a lighthouse. • Approximately 2000 have been found. • pulsars are among the most Courtesy: A.Noutsos (MPIfR) polarized of all known radio sources. Friday, June 7, 13
Pulsar Observations Friday, June 7, 13
Pulsar Observations Friday, June 7, 13
Effelsberg 0 Effelsberg horizon 30 surrounded by a valley 60 pulsar loccation The circumpolar PSR B0329+54 track Friday, June 7, 13
Station Stability Monitoring A circumpolar PSR B0329 observation, day-long sequence of hourly observations lasting a few minutes each Friday, June 7, 13
Station Stability Monitoring A circumpolar PSR B0329 observation, day-long sequence of hourly observations lasting a few minutes each Friday, June 7, 13
Station Stability Monitoring Friday, June 7, 13
Dispersion Measure (DM) After removing dispersion which accounts for the correction with DM 26.833 (pulsar catalogue). − D × DM The quadratic frequency dependence of DM delay f 2 e 2 n: electron number density D = 2 π m e c D: dispersion constant leaning to the right a little bit ? d e: charge of an electron ∫ DM = n e dl 0 m: mass of an electron Friday, June 7, 13
Friday, June 7, 13
DM Measurement with LOFAR DM 26.83 (1986): Lovell DM 26.76 (2013): LOFAR total total linear linear circular circular Friday, June 7, 13
LOFAR's Applicability to High Precision Timing Measurements of interstellar dispersion to the pulsar J2145 ‐ 0750. • In high-precision timing, the biggest problem is variations in DM. • LOFAR works at lower frequencies, which can make these measurements much more Courtesy: J.Verbiest (MPIfR) accurately and can measure DM variations at a much more precise The Universe is filled level. with a background of gravitational waves. Friday, June 7, 13
Individual pulses Pulse number ! • A mean value • A rich variety structure • A wealth of emission process • Time-variable plasma processes Pulse phase ! create 0.714 (s) Friday, June 7, 13
Jones Matrix Hamaker. J Friday, June 7, 13
Friday, June 7, 13
Friday, June 7, 13
The first discovered pulsar CP1919 Jocelyn Bell & Antony Hewish Nobel Prize in Physics in 1972 Friday, June 7, 13
Public Outreach (brainwashing kids into SKA) 2013-01-27 Düsseldorf, Germany total ! linear ! circular ! Our group has been involved in public outreach, organizing lectures at schools, where the general public was given a chance to perform pulsar observations with LOFAR. The young students were excited to see the profile of the first discovered pulsar CP1919, in 30 seconds of LOFAR data. Friday, June 7, 13
Thank you for your attention! Friday, June 7, 13
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