High-Resolution Radio Imaging of Gravitational Lensing Candidates in the 1 Jansky BL Lacertae Sample

2003 ◽  
Vol 125 (5) ◽  
pp. 2447-2454 ◽  
Author(s):  
Travis A. Rector ◽  
John T. Stocke
Keyword(s):  
High Resolution ◽  
Gravitational Lensing ◽  
Bl Lacertae ◽  
Radio Imaging

Gravitational Lensing Studies of High Resolution Cluster Simulations

2005 ◽  
Vol 201 ◽  
pp. 476-477
Author(s):  
Lindsay King ◽  
Douglas Clowe ◽  
Peter Schneider ◽  
Volker Springel
Keyword(s):  
High Resolution ◽  
Gravitational Lensing ◽  
Particle Mass ◽  
Weak Lensing ◽  
Reconstruction Technique ◽  
Ongoing Work ◽  
Non Parametric

In our ongoing work, we use high resolution cluster simulations to study gravitational lensing. These simulations have a softening length of 0.7 h-1 kpc and a particle mass of 4.68 × 107M⊙ (Springel 1999). Questions that can be addressed include the accuracy with which substructure on various scales can be recovered using the information from lensing. This is very important in determining the power of lensing in studying the evolution of cluster substructure as a function of redshift. We briefly consider how a weak lensing non-parametric reconstruction technique and the Map-statistic can be applied to the simulations.

Very high-resolution observations of the radio sources NRAO 150, OJ 287, 3C 273, M87, 1633 + 38, BL Lacertae, and 3C 454.3

1977 ◽  
Vol 211 ◽  
pp. 658 ◽  
Author(s):  
K. I. Kellermann ◽  
D. B. Shaffer ◽  
G. H. Purcell ◽  
I. I. K. Pauliny-Toth ◽  
E. Preuss ◽  
...  
Keyword(s):  
High Resolution ◽  
Radio Sources ◽  
Bl Lacertae ◽  
Very High

scholarly journals High-resolution radio imaging of two luminous quasars beyond redshift 4.5

2018 ◽  
Vol 618 ◽  
pp. A68 ◽  
Author(s):  
S. Frey ◽  
O. Titov ◽  
A. E. Melnikov ◽  
P. de Vicente ◽  
F. Shu
Keyword(s):  
High Resolution ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Brightness Distribution ◽  
Distribution Model ◽  
Radio Structure ◽  
Long Baseline ◽  
Radio Imaging ◽  
Jet Structure ◽  
East West

Context. Radio-loud active galactic nuclei in the early Universe are rare. The quasars J0906+6930 at redshift z = 5.47 and J2102+6015 at z = 4.57 stand out from the known sample with their compact emission on milliarcsecond (mas) angular scale with high (0.1 Jy level) flux densities measured at GHz radio frequencies. This makes them ideal targets for very long baseline interferometry (VLBI) observations. Aims. By means of VLBI imaging we can reveal the inner radio structure of quasars and model their brightness distribution to better understand the geometry of the jet and the physics of the sources. Methods. We present sensitive high-resolution VLBI images of J0906+6930 and J2102+6015 at two observing frequencies, 2.3 and 8.6 GHz. The data were taken in an astrometric observing programme involving a global five-element radio telescope array. We combined the data from five different epochs from 2017 February to August. Results. For one of the highest redshift blazars known, J0906+6930, we present the first-ever VLBI image obtained at a frequency below 8 GHz. Based on our images at 2.3 and 8.6 GHz, we confirm that this source has a sharply bent helical inner jet structure within ∼3 mas from the core. The quasar J2102+6015 shows an elongated radio structure in the east–west direction within the innermost ∼2 mas that can be described with a symmetric three-component brightness distribution model at 8.6 GHz. Because of their non-pointlike mas-scale structure, these sources are not ideal as astrometric reference objects. Our results demonstrate that VLBI observing programmes conducted primarily with astrometric or geodetic goals can be utilized for astrophysical purposes as well.

scholarly journals Direct Mapping of Massive Compact Objects in Extragalactic Dark Halos

2004 ◽  
Vol 220 ◽  
pp. 139-140
Author(s):  
Kaiki Taro Inoue ◽  
Masashi Chiba
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Density Profile ◽  
Gravitational Lensing ◽  
Galactic Halo ◽  
Compact Objects ◽  
Multiple Images ◽  
Direct Mapping ◽  
Radio Map

We propose a method for directly detecting MASsive Compact Objects (MASCOs) in extragalactic halos, using VLBI techniques with extremely high resolution ˜ 0.01 milli-arcsec. If a galactic halo comprising a large number of MASCOs produces multiple images of a background radio-loud QSO by gravitational lensing, then a high-resolution radio map of each macro-lensed image should reveal microlensing effects by MASCOs. Based on the size, position, and magnified or demagnified patterns of images, we shall be able to determine the mass and density profile of an individual MASCO as well as its spatial distribution and abundance in a galactic halo.

scholarly journals The jet collimation profile at high resolution in BL Lacertae

2021 ◽  
Author(s):  
C. Casadio ◽  
N. R. MacDonald ◽  
B. Boccardi ◽  
S. G. Jorstad ◽  
A. P. Marscher ◽  
...  
Keyword(s):  
High Resolution ◽  
Bl Lacertae ◽  
Jet Collimation

Prevalence of radio jets associated with quasar outflows and feedback

2018 ◽  
Vol 14 (A30) ◽  
pp. 70-73
Author(s):  
Miranda E. Jarvis
Keyword(s):  
High Resolution ◽  
Ionized Gas ◽  
Gas Kinematics ◽  
Radio Jets ◽  
Radio Imaging ◽  
Multi Wavelength ◽  
Pilot Sample

AbstractWe have identified that radio jets are commonly associated with “radiative mode” feedback in quasars. By performing a systematic multi-wavelength study of z < 0.2 quasars, we have found that 70–80% of our sample of ‘radio-quiet’ type 2 quasars, which host kpc-scale ionized gas outflows, exhibit radio jet structures. Here, we discuss our results on the pilot sample of 10 objects that combine high resolution (∼ 0.25 - 1 arcsec) radio imaging at 1-7 GHz with optical IFU observations. Our results demonstrate that it is extremely common for jets to be spatially and kinematically linked to kpc-scale ionized gas kinematics in such quasars. Therefore, radio jets may be an important driver of outflows during ‘radiative mode’ feedback, apparently blurring the lines between the traditional divisions of feedback modes.

scholarly journals Deep Radio Imaging with MERLIN of the Supernova Remnants in M82

2005 ◽  
Vol 192 ◽  
pp. 227-231
Author(s):  
T.W.B. Muxlow ◽  
A. Pedlar ◽  
J.D. Riley ◽  
A.R. McDonald ◽  
R.J. Beswick ◽  
...  
Keyword(s):  
High Resolution ◽  
Supernova Remnants ◽  
Shell Structures ◽  
Starburst Galaxy ◽  
Radio Structure ◽  
High Resolution Image ◽  
Radio Imaging ◽  
Wide Range ◽  
Deep Integration ◽  
First Time

SummaryAn 8 day MERLIN deep integration at 5GHz of the central region of the starburst galaxy M82 has been used to investigate the radio structure of a number of supernova remnants in unprecedented detail revealing new shells and partial shell structures for the first time. In addition, by comparing the new deep 2002 image with an astrometrically aligned image from 36 hours of data taken in 1992, it has been possible to directly measure the expansion velocities of 4 of the most compact remnants in M82. For the two most compact remnants, 41.95+575 and 43.31+592, expansion velocities of 2800 ± 300 km s-1 and 8750 ± 400kms-1have been derived. These confirm and refine the measured expansion velocities which have been derived from VLBI multi-epoch studies. For remnants 43.18+583 and 44.01+596, expansion velocities of 10500 ± 750km s-1 and 2400 ± 250 kms-1have been measured for the first time. In addition, the peak of the radio emission for SNR 45.17+612 has moved between the two epochs implying velocities around 7500km s-1. The relatively compact remnants in M82 are thus found to be expanding over a wide range of velocities which appear unrelated to their size. The new 2002 map is the most sensitive high-resolution image yet made of M82, achieving an rms noise level of 17μJy beam-1. This establishes a first epoch for subsequent deep studies of expansion velocities for many SNR within M82.

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