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We have measured the scattering timescale, $\tau$, and the scattering spectral index, $\alpha$, for 84 single-component pulsars. Observations were carried out with the MeerKAT telescope as part of the Thousand-Pulsar-Array programme in the…

We present the first large sample of scintillation arcs in millisecond pulsars, analysing 12 sources observed with the Large European Array for Pulsars (LEAP), and the Effelsberg 100\,m telescope. We estimate the delays from multipath…

The Zurich IMaging POLarimeter (ZIMPOL) developed at ETH Zurich and installed permanently at the Gregory Coude Telescope at Istituto Ricerche Solari Locarno (IRSOL) allows a polarimetric precision down to 10^-5 to be reached. This makes it…

太阳与恒星天体物理 · 物理学 2009-06-15 R. Ramelli , M. Bianda , J. O. Stenflo , P. Jetzer

Using data from the Large European Array for Pulsars (LEAP), and the Effelsberg telescope, we study the scintillation parameters of the millisecond pulsar J0613-0200 over a 7 year timespan. The "secondary spectrum" -- the 2D power spectrum…

We present the measurements of scatter broadening time-scales ($\tau_{sc}$) for 124 pulsars at 327 MHz, using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37 $-$ 503 pc cm$^{-3}$ and…

高能天体物理现象 · 物理学 2017-06-20 M. A. Krishnakumar , Dipanjan Mitra , Arun Naidu , Bhal Chandra Joshi , P. K. Manoharan

We analyse the feasibility of detecting the polarization of the CMB caused by scattering of the remote temperature quadrupole by galaxy clusters with forthcoming CMB polarization surveys. For low-redshift clusters, the signal is strongly…

宇宙学与河外天体物理 · 物理学 2014-09-24 Alex Hall , Anthony Challinor

We analyze data from the Helioseismic Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) instruments on board the Solar Dynamics Observatory (SDO) to characterize the spatio-temporal acoustic power distribution in active…

太阳与恒星天体物理 · 物理学 2017-11-06 S. C. Tripathy , K. Jain , S. Kholikov , F. Hill , S. P. Rajaguru , P. S. Cally

Aims: We study possible signs of asymmetry in the luminous Type IIn SN2010jl, to obtain independent information on the explosion geometry. Methods: We obtained optical linear spectropolarimetry of SN2010jl two weeks after the discovery, in…

宇宙学与河外天体物理 · 物理学 2015-05-20 F. Patat , S. Taubenberger , S. Benetti , A. Pastorello , A. Harutyunyan

The linear polarization pattern produced by scattering processes in the Ca I resonance line at 4227 angstroms is a valuable observable for probing the solar atmosphere. Via the Hanle effect, the very significant Q/I and U/I line-center…

太阳与恒星天体物理 · 物理学 2018-02-28 E. Alsina Ballester , L. Belluzzi , J. Trujillo Bueno

Until recently, the strong interstellar scattering observed towards the Galactic center (GC) black hole, Sgr A*, was thought to come from dense gas within the GC region. The pulse broadening towards the transient magnetar SGR J1745-2900…

星系天体物理 · 物理学 2017-01-25 Egid Sicheneder , Jason Dexter

Observing giant HII regions at fine spatial scales uncovers detailed structures and reveals variations in ionization, abundance, and dynamical properties of ionized gas and the effect of stellar feedback. Using emission line data of M33…

An attractive diagnostic tool for investigating the magnetism of the solar chromosphere is the observation and theoretical modeling of the Hanle and Zeeman effects in spicules, as shown in this letter for the first time. Here we report on…

天体物理学 · 物理学 2009-11-10 J. Trujillo Bueno , L. Merenda , R. Centeno , M. Collados , E. Landi Degl'Innocenti

We present some theoretical predictions concerning the amplitude and magnetic sensitivity of the linear polarization signals produced by scattering processes in the hydrogen Ly-alpha line of the solar transition region. To this end, we have…

太阳与恒星天体物理 · 物理学 2015-05-28 Javier Trujillo Bueno , Jiri Stepan , Roberto Casini

Spicules are small hairy like structures seen at the solar limb mainly at chromospheric and transition region lines. They generally live for 3-10 minutes. We observe these spicules in a south polar region of the Sun with a coordinated…

太阳与恒星天体物理 · 物理学 2015-12-16 Tanmoy Samanta , Vaibhav Pant , Dipankar Banerjee

The linear polarization produced by scattering processes in the hydrogen Lyman alpha line of the solar disk radiation is a key observable for probing the chromosphere-corona transition region (TR) and the underlying chromospheric plasma.…

太阳与恒星天体物理 · 物理学 2019-08-14 Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

We have used polarimetric imaging to study the magneto-ionic medium of the Galaxy, obtaining 1420 MHz images with an angular resolution of 1' over more than 40 square-degrees of sky around the W3/W4/W5/HB3 HII region/SNR complex in the…

天体物理学 · 物理学 2009-10-31 A. D. Gray , T. L. Landecker , P. E. Dewdney , A. R. Taylor , A. G. Willis , M. Normandeau

We employ the magnetic and velocity fields from turbulent dynamo simulations to synthesize the polarization of a typical photospheric line. The synthetic Stokes profiles have properties in common with those observed in the quiet Sun. The…

天体物理学 · 物理学 2009-11-07 J. Sánchez Almeida , T. Emonet , F. Cattaneo

New spatially scanned spectropolarimetry sunspot observations are made of photospheric atomic and molecular absorption lines near 4135nm. The relative splittings among several atomic lines are measured and shown to agree with values…

太阳与恒星天体物理 · 物理学 2016-09-28 M Penn , H Uitenbroek , TA Clark , R Coulter , PR Goode , W Cao

Polarized synchrotron emission from ultra-relativistic electrons spiraling the Galactic magnetic field has become one of the most relevant emissions in the Interstellar medium these last years due to the improvement in the quality of…

We investigate temporally changing variability amplitudes and the multi-periodicity of the type-I Cepheid Polaris using 161 high-precision radial velocity (RV) and bisector inverse span (BIS) measurements based on optical spectra recorded…

太阳与恒星天体物理 · 物理学 2019-03-27 Richard I. Anderson