CHANG-ES. IV. RADIO CONTINUUM EMISSION OF 35 EDGE-ON GALAXIES OBSERVED WITH THE KARL G. JANSKY VERY LARGE ARRAY IN D CONFIGURATION—DATA RELEASE 1

Abstract 3FGL J1544.6−1125 is a candidate transitional millisecond pulsar (tMSP). Similar to the well-established tMSPs—PSR J1023+0038, IGR J18245−2452, and XSS J12270−4859—3FGL J1544.6−1125 shows γ-ray emission and discrete X-ray “low” and “high” modes during its low-luminosity accretion-disk state. Coordinated radio/X-ray observations of PSR J1023+0038 in its current low-luminosity accretion-disk state showed rapidly variable radio continuum emission—possibly originating from a compact, self-absorbed jet, the “propellering” of accretion material, and/or pulsar moding. 3FGL J1544.6−1125 is currently the only other (candidate) tMSP system in this state, and can be studied to see whether tMSPs are typically radio-loud compared to other neutron star binaries. In this work, we present a quasi-simultaneous Very Large Array and Swift radio/X-ray campaign on 3FGL J1544.6−1125. We detect 10 GHz radio emission varying in flux density from 47.7 ± 6.0 μJy down to ≲15 μJy (3σ upper limit) at four epochs spanning three weeks. At the brightest epoch, the radio luminosity is L 5 GHz = (2.17 ± 0.17) × 1027 erg s−1 for a quasi-simultaneous X-ray luminosity L 2–10 keV = (4.32 ± 0.23) × 1033 erg s−1 (for an assumed distance of 3.8 kpc). These luminosities are close to those of PSR J1023+0038, and the results strengthen the case that 3FGL J1544.6−1125 is a tMSP showing similar phenomenology to PSR J1023+0038.

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Observations of H2O maser and continuum emission in AFGL 2591

Symposium - International Astronomical Union ◽

10.1017/s0074180900222080 ◽

2002 ◽

Vol 206 ◽

pp. 68-71

Author(s):

Miguel A. Trinidad ◽

Salvador Curiel ◽

Jorge Cantó ◽

José M. Torrelles ◽

Luis F. Rodríguez ◽

...

Keyword(s):

Radio Continuum ◽

Continuum Emission ◽

Molecular Flow ◽

Large Array ◽

Very Large Array ◽

Star Forming ◽

Bipolar Outflow ◽

Maser Line ◽

H Ii Region

We report results of radio continuum (1.3 and 3.6 cm) and H2O maser line observations, made with the Very Large Array (A configuration), toward the star-forming region AFGL 2591. We detected 85 maser spots toward this region, which are distributed in three main groups. Two of these groups spatially coincide with the radio continuum sources VLA 2 and VLA 3. The maser spots associated with VLA 3 are distributed along a shell-like structure of 0.01 and nearly perpendicular to the CO bipolar outflow. We propose that VLA 3 is the center of the observed molecular flow in this region. Finally, we confirm that AFGL 2591 region is a cluster of B type stars, each one with its own optically thin H II region.

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Neutral Hydrogen in HCG 95

International Astronomical Union Colloquium ◽

10.1017/s0252921100054919 ◽

2000 ◽

Vol 174 ◽

pp. 154-157 ◽

Cited By ~ 1

Author(s):

W. K. Huchtmeier ◽

Lourdes Verdes-Montenegro ◽

Min Yun ◽

A. del Olmo ◽

J. Perea

Keyword(s):

Spiral Galaxies ◽

Dwarf Galaxies ◽

Elliptical Galaxy ◽

Neutral Hydrogen ◽

Radio Continuum ◽

Continuum Emission ◽

Large Array ◽

Foreground Object ◽

Very Large Array ◽

Group Center

AbstractWe have observed Hɪ emission and radio continuum emission from the compact group of galaxies HCG 95 with the Very Large Array (VLA)1. Two continuum sources coincide in with galaxies in this group: HCG 95 B (3.9 mJy) and HCG95C (6 mJy). Hɪ emission and absorption was detected in galaxy HCG 95 C. In addition we detected two so far unknown dwarf galaxies by their Hɪ emission within 3.5 arcmin of the group center. We did not detect galaxy b (with ç = 8000 kms−1 it is obviously a foreground object) and galaxy d — an edge-on Sc galaxy. This group definitely is Hɪ deficient compared with the average Hɪ content expected for spiral galaxies of the same luminosity and type. The first-ranked elliptical galaxy HCG 95 A might be responsible for the observed Hɪ deficiency in this group.

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A Multi-Epoch Study of Radio Continuum Emission from Massive Protostars

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3999 ◽

2020 ◽

Author(s):

W O Obonyo ◽

S L Lumsden ◽

M G Hoare ◽

S E Kurtz ◽

S J D Purser

Keyword(s):

Spectral Index ◽

The Other ◽

Radio Continuum ◽

Continuum Emission ◽

Gas Bubble ◽

Large Array ◽

Proper Motions ◽

Very Large Array ◽

The Core ◽

Displacement Vectors

Abstract We report the results of the Jansky Very Large Array (JVLA) observation of five massive protostars at 6 and 22.2 GHz. The aim of the study was to compare their current fluxes and positions with previous observations to search for evidence of variability. Most of the observed sources present the morphologies of a thermal core, hosting the protostar and exhibiting no proper motion, and associated non-thermal radio lobes that are characterised by proper motions and located away from the thermal core. Some of the protostars drive jets whose lobes have dissimilar displacement vectors, implying precession of the jets or the presence of multiple jet drivers. The jets of the protostars were found to have proper motions that lie in the range 170≤v ≤650 kms−1, and precessions of periods 40≤p ≤50 years and angles 2≤α ≤ 10○, assuming that their velocities v =500 kms−1. The core of one of the sources, S255 NIRS 3, which was in outburst at the time of our observations, showed a significant change in flux compared to the other sources. Its spectral index decreased during the outburst, consistent with the model of an expanding gas bubble. Modelling the emission of the outburst as that of a new non-thermal lobe that is emerging from a thermal core whose emission enshrouds that of the lobe also has the potential to account for the increase in flux and a decrease in the spectral index of the source’s outburst.

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The Nature of Radio Continuum Emission at Very Low Metallicity: Very Large Array Observations of I Zw 18

The Astrophysical Journal ◽

10.1086/428943 ◽

2005 ◽

Vol 621 (1) ◽

pp. L21-L24 ◽

Cited By ~ 12

Author(s):

John M. Cannon ◽

Fabian Walter ◽

Evan D. Skillman ◽

Liese van Zee

Keyword(s):

Radio Continuum ◽

Continuum Emission ◽

Large Array ◽

Very Large Array ◽

Low Metallicity

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Bipolar outflow of gas in the spiral galaxy NGC 3079

Canadian Journal of Physics ◽

10.1139/p86-100 ◽

1986 ◽

Vol 64 (4) ◽

pp. 531-535 ◽

Cited By ~ 1

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.

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Low frequency (74 MHz) radio continuum observations of the inner 13° × 7° of the Galactic center

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314001161 ◽

2013 ◽

Vol 9 (S303) ◽

pp. 464-466

Author(s):

M. Rickert ◽

F. Yusef-Zadeh ◽

C. Brogan

Keyword(s):

High Resolution ◽

Molecular Cloud ◽

Supernova Remnant ◽

Galactic Center ◽

Low Frequency ◽

Radio Continuum ◽

Large Array ◽

Very Large Array ◽

Image Displays ◽

Western Side

AbstractWe analyze a high resolution (114″ × 60″) 74 MHz image of the Galactic center taken with the Very Large Array (VLA). We have identified several absorption and emission features in this region, and we discuss preliminary results of two Galactic center sources: the Sgr D complex (G1.1–0.1) and the Galactic center lobe (GCL).The 74 MHz image displays the thermal and nonthermal components of Sgr D and we argue the Sgr D supernova remnant (SNR) is consistent with an interaction with a nearby molecular cloud and the location of the Sgr D Hii region on the near side of the Galactic center. The image also suggests that the emission from the eastern side of the GCL contains a mixture of both thermal and nonthermal sources, whereas the western side is primarily thermal.

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Investigation of the cosmic ray population and magnetic field strength in the halo of NGC 891

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832837 ◽

2018 ◽

Vol 615 ◽

pp. A98 ◽

Cited By ~ 15

Author(s):

D. D. Mulcahy ◽

A. Horneffer ◽

R. Beck ◽

M. Krause ◽

P. Schmidt ◽

...

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Low Frequency ◽

Cosmic Ray ◽

Radio Continuum ◽

Continuum Emission ◽

Low Frequencies ◽

Very Large Array ◽

Field Strengths

Context. Cosmic rays and magnetic fields play an important role for the formation and dynamics of gaseous halos of galaxies. Aims. Low-frequency radio continuum observations of edge-on galaxies are ideal to study cosmic-ray electrons (CREs) in halos via radio synchrotron emission and to measure magnetic field strengths. Spectral information can be used to test models of CRE propagation. Free–free absorption by ionized gas at low frequencies allows us to investigate the properties of the warm ionized medium in the disk. Methods. We obtained new observations of the edge-on spiral galaxy NGC 891 at 129–163 MHz with the LOw Frequency ARray (LOFAR) and at 13–18 GHz with the Arcminute Microkelvin Imager (AMI) and combine them with recent high-resolution Very Large Array (VLA) observations at 1–2 GHz, enabling us to study the radio continuum emission over two orders of magnitude in frequency. Results. The spectrum of the integrated nonthermal flux density can be fitted by a power law with a spectral steepening towards higher frequencies or by a curved polynomial. Spectral flattening at low frequencies due to free–free absorption is detected in star-forming regions of the disk. The mean magnetic field strength in the halo is 7 ± 2 μG. The scale heights of the nonthermal halo emission at 146 MHz are larger than those at 1.5 GHz everywhere, with a mean ratio of 1.7 ± 0.3, indicating that spectral ageing of CREs is important and that diffusive propagation dominates. The halo scale heights at 146 MHz decrease with increasing magnetic field strengths which is a signature of dominating synchrotron losses of CREs. On the other hand, the spectral index between 146 MHz and 1.5 GHz linearly steepens from the disk to the halo, indicating that advection rather than diffusion is the dominating CRE transport process. This issue calls for refined modelling of CRE propagation. Conclusions. Free–free absorption is probably important at and below about 150 MHz in the disks of edge-on galaxies. To reliably separate the thermal and nonthermal emission components, to investigate spectral steepening due to CRE energy losses, and to measure magnetic field strengths in the disk and halo, wide frequency coverage and high spatial resolution are indispensable.

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SuperCLASS – I. The super cluster assisted shear survey: Project overview and data release 1

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa709 ◽

2020 ◽

Vol 495 (2) ◽

pp. 1706-1723 ◽

Cited By ~ 1

Author(s):

Richard A Battye ◽

Michael L Brown ◽

Caitlin M Casey ◽

Ian Harrison ◽

Neal J Jackson ◽

...

Keyword(s):

Cross Correlation ◽

Near Infrared ◽

Correlation Technique ◽

Large Array ◽

Photometric Redshifts ◽

Very Large Array ◽

Infrared Observations ◽

Data Release ◽

L Band ◽

Cross Correlation Technique

ABSTRACT The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4 GHz) to a r.m.s. of $7\, \mu {\rm Jy}\,$beam−1 over an area of $\sim 1\, {\rm deg}^2$ centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements with the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity out to z ∼ 1. In this paper we give an overview of the project including the science goals and multiwavelength coverage before presenting the first data release. We have analysed around 400 h of e-MERLIN data allowing us to create a Data Release 1 (DR1) mosaic of $\sim 0.26\, {\rm deg}^2$ to the full depth. These observations have been supplemented with complementary radio observations from the Karl G. Jansky Very Large Array (VLA) and optical/near infrared observations taken with the Subaru, Canada-France-Hawaii, and Spitzer Telescopes. The main data product is a catalogue of 887 sources detected by the VLA, of which 395 are detected by e-MERLIN and 197 of these are resolved. We have investigated the size, flux, and spectral index properties of these sources finding them compatible with previous studies. Preliminary photometric redshifts, and an assessment of galaxy shapes measured in the radio data, combined with a radio-optical cross-correlation technique probing cosmic shear in a supercluster environment, are presented in companion papers.

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