scholarly journals WIDEBAND VERY LARGE ARRAY OBSERVATIONS OF A2256. I. CONTINUUM, ROTATION MEASURE, AND SPECTRAL IMAGING

2014 ◽  
Vol 794 (1) ◽  
pp. 24 ◽  
Author(s):  
Frazer N. Owen ◽  
Lawrence Rudnick ◽  
Jean Eilek ◽  
Urvashi Rau ◽  
Sanjay Bhatnagar ◽  
...  
Keyword(s):  
Spectral Imaging ◽  
Large Array ◽  
Very Large Array ◽  
Rotation Measure

scholarly journals Magnetic-Field Vector Maps of Nearby Spiral Galaxies

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 32 ◽  
Author(s):  
Hiroyuki Nakanishi ◽  
Kohei Kurahara ◽  
Kenta Anraku
Keyword(s):  
Magnetic Field ◽  
Spiral Galaxies ◽  
Transverse Magnetic ◽  
Field Vector ◽  
Line Of Sight ◽  
Large Array ◽  
Magnetic Vector ◽  
Very Large Array ◽  
Rotation Measure ◽  
The Galaxy

We present a method for determining the directions of magnetic-field vectors in a spiral galaxy using two synchrotron polarization maps, an optical image, and a velocity field. The orientation of the transverse magnetic field is determined with a synchrotron polarization map of a higher-frequency band, and the 180 ∘ -ambiguity is solved by using a sign of Rotation Measure (RM) after determining the geometrical orientation of a disk based on an assumption of trailing spiral arms. The advantage of this method is that the direction of a magnetic vector for each line of sight throughout the galaxy can inexpensively be determined, with easily available data and simple assumptions. We applied this method to three nearby spiral galaxies using archival data obtained with a Very Large Array (VLA) to demonstrate how it works. The three galaxies have both clockwise and counterclockwise magnetic fields, which implies that none of the three galaxies is classified in a simple Axis-Symmetric type, but types of higher modes, and that magnetic reversals commonly exist.

scholarly journals Deep Very Large Array Observations of the Merging Cluster CIZA J2242.8+5301: Continuum and Spectral Imaging

2018 ◽  
Vol 865 (1) ◽  
pp. 24 ◽  
Author(s):  
G. Di Gennaro ◽  
R. J. van Weeren ◽  
M. Hoeft ◽  
H. Kang ◽  
D. Ryu ◽  
...  
Keyword(s):  
Spectral Imaging ◽  
Large Array ◽  
Very Large Array

scholarly journals 28–40 GHz variability and polarimetry of bright compact sources in the QUIJOTE cosmological fields

2021 ◽  
Vol 502 (4) ◽  
pp. 4779-4793
Author(s):  
Yvette C Perrott ◽  
Marcos López-Caniego ◽  
Ricardo T Génova-Santos ◽  
Jose Alberto Rubiño-Martín ◽  
Mark Ashdown ◽  
...  
Keyword(s):  
Point Source ◽  
Radio Frequency ◽  
Flux Density ◽  
Lognormal Distribution ◽  
Large Array ◽  
Very Large Array ◽  
Rotation Measure ◽  
Apparent Correlation ◽  
Compact Sources ◽  
Polarization Fraction

ABSTRACT We observed 51 sources in the Q-U-I JOint TEnerife (QUIJOTE) cosmological fields that were brighter than 1 Jy at 30 GHz in the Planck Point Source Catalogue (version 1), with the Very Large Array at 28–40 GHz, in order to characterize their high-radio-frequency variability and polarization properties. We find a roughly lognormal distribution of polarization fractions with a median of 2 per cent, in agreement with previous studies, and a median rotation measure (RM) of ≈1110 rad m−2 with one outlier up to ≈64 000 rad m−2, which is among the highest RMs measured in quasar cores. We find hints of a correlation between the total intensity  flux density and median polarization fraction. We find 59 per cent of sources are variable in total intensity, and 100 per cent in polarization at 3σ level, with no apparent correlation between total intensity variability and polarization variability. This indicates that it will be difficult to model these sources without simultaneous polarimetric monitoring observations and they will need to be masked for cosmological analysis.

scholarly journals MODELING THE MAGNETIC FIELD IN THE GALACTIC DISK USING NEW ROTATION MEASURE OBSERVATIONS FROM THE VERY LARGE ARRAY

2011 ◽  
Vol 728 (2) ◽  
pp. 97 ◽  
Author(s):  
C. L. Van Eck ◽  
J. C. Brown ◽  
J. M. Stil ◽  
K. Rae ◽  
S. A. Mao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Galactic Disk ◽  
Large Array ◽  
Very Large Array ◽  
Rotation Measure ◽  
The Magnetic Field

Multiwavelength analysis of OH Megamaser galaxies: The case of IRAS11506-3851

2020 ◽  
Vol 15 (S359) ◽  
pp. 347-349
Author(s):  
Carpes P. Hekatelyne ◽  
Thaisa Storchi-Bergmann
Keyword(s):  
Active Galactic Nuclei ◽  
Hubble Space Telescope ◽  
Galactic Nuclei ◽  
Large Array ◽  
Very Large Array ◽  
Star Forming ◽  
Star Forming Regions ◽  
Field Unit ◽  
Mixed Transition ◽  
Integral Field

AbstractWe present Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST) and Very Large Array (VLA) observations of the inner kpc of the OH Megamaser galaxy IRAS 11506-3851. In this work we discuss the kinematics and excitation of the gas as well as its radio emission. The HST images reveal an isolated spiral galaxy and the combination with the GMOS-IFU flux distributions allowed us to identify a partial ring of star-forming regions surrounding the nucleus with a radius of ≍500 pc. The emission-line ratios and excitation map reveal that the region inside the ring present mixed/transition excitation between those of Starbursts and Active Galactic Nuclei (AGN), while regions along the ring are excited by Starbursts. We suggest that we are probing a buried or fading AGN that could be both exciting the gas and originating an outflow.

scholarly journals OH main line masers in the M 82 starburst

2007 ◽  
Vol 3 (S242) ◽  
pp. 427-431
Author(s):  
M. K. Argo ◽  
A. Pedlar ◽  
T. W. B. Muxlow ◽  
R. J. Beswick
Keyword(s):  
Central Region ◽  
Supernova Remnants ◽  
Main Line ◽  
Line Of Sight ◽  
Starburst Galaxy ◽  
Large Array ◽  
Satellite Line ◽  
Very Large Array

AbstractA study of the distribution of OH gas in the central region of the nearby active starburst galaxy M82 has confirmed two previously known bright masers and revealed several new main line masers. Three of these are seen only at 1665 MHz, one is detected only at 1667 MHz, while the rest are detected in both lines. Observations covering both the 1665 and 1667 MHz lines, conducted with both the Very Large Array (VLA) and the Multi-Element Radio Linked Interferometer Network (MERLIN), have been used to accurately measure the positions and velocities of these features. This has allowed a comparison with catalogued continuum features in the starburst such as HII regions and supernova remnants, as well as known water and satellite line OH masers. Most of the main line masers appear to be associated with known HII regions although the two detected only at 1665 MHz are seen along the same line of sight as known supernova remnants.

Bipolar outflow of gas in the spiral galaxy NGC 3079

1986 ◽  
Vol 64 (4) ◽  
pp. 531-535 ◽  
Author(s):  
Nebojsa Duric ◽  
E. R. Seaquist
Keyword(s):  
Spectral Index ◽  
Spiral Galaxy ◽  
Central Region ◽  
Qualitative Description ◽  
Radio Continuum ◽  
Large Array ◽  
Very Large Array ◽  
Bipolar Outflow ◽  
The Galaxy

Very large array, radio-continuum observations of the edge-on spiral galaxy NGC 3079 are presented. The observations reveal that the nucleus has windlike properties and that the central region of the galaxy exhibits an unusual figure-eight morphology that shows evidence of severe depolarization and a flattening spectral index away from the nucleus. A qualitative description of a model is presented to account for the observed radio properties. It is shown that a wind-driven shock propagating away from the nucleus and focused by the ambient disk gas can give rise to the observed morphology.

scholarly journals realfast: Real-time, Commensal Fast Transient Surveys with the Very Large Array

2018 ◽  
Vol 236 (1) ◽  
pp. 8 ◽  
Author(s):  
C. J. Law ◽  
G. C. Bower ◽  
S. Burke-Spolaor ◽  
B. J. Butler ◽  
P. Demorest ◽  
...  
Keyword(s):  
Real Time ◽  
Large Array ◽  
Very Large Array ◽  
Fast Transient
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