scholarly journals The radio-X-ray relation as a star formation indicator: results from the Very Large Array-Extended Chandra Deep Field-South

2012 ◽  
Vol 420 (3) ◽  
pp. 2190-2208 ◽  
Author(s):  
S. Vattakunnel ◽  
P. Tozzi ◽  
F. Matteucci ◽  
P. Padovani ◽  
N. Miller ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Array ◽  
Very Large Array ◽  
X Ray

scholarly journals Quasi-simultaneous Radio/X-Ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6−1125 during its Low-luminosity Accretion-disk State

2021 ◽  
Vol 923 (1) ◽  
pp. 3
Author(s):  
Amruta D. Jaodand ◽  
Adam T. Deller ◽  
Nina Gusinskaia ◽  
Jason W. T. Hessels ◽  
James C. A. Miller-Jones ◽  
...  
Keyword(s):  
Accretion Disk ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Large Array ◽  
Millisecond Pulsar ◽  
Very Large Array ◽  
X Ray ◽  
Upper Limit ◽  
5 Ghz ◽  
Variable Radio

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.

scholarly journals Radio morphology of southern narrow-line Seyfert 1 galaxies with Very Large Array observations*

2020 ◽  
Vol 498 (1) ◽  
pp. 1278-1297
Author(s):  
S Chen ◽  
E Järvelä ◽  
L Crepaldi ◽  
M Zhou ◽  
S Ciroi ◽  
...  
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Large Mass ◽  
Large Array ◽  
Narrow Line ◽  
Diffuse Emission ◽  
Jets And Outflows ◽  
Very Large Array ◽  
Radio Jets ◽  
New Radio

ABSTRACT We present the results of new radio observations carried out with the Karl G. Jansky Very Large Array C-configuration at 5.5 GHz for a sample of southern narrow-line Seyfert 1 galaxies (NLS1s). This work increases the number of known radio-detected NLS1s in the Southern hemisphere, and confirms that the radio emission of NLS1s is mainly concentrated in a central region at kpc-scale and only a few sources show diffuse emission. In radio-quiet NLS1s, the radio luminosity tends to be higher in steep-spectrum sources and be lower in flat-spectrum sources, which is opposite to radio-loud NLS1s. This may be because the radio emission of steep NLS1s is dominated by misaligned jets, active galactic nucleus driven outflows, or star formation superposing on a compact core. Instead the radio emission of flat NLS1s may be produced by a central core that has not yet developed radio jets and outflows. We discover new NLS1s harbouring kpc-scale radio jets and confirm that a powerful jet does not require a large-mass black hole to be generated. We also find sources dominated by star formation. These NLS1s could be new candidates in investigating the radio emission of different mechanisms.

VLA Observations of a Sample of Low-Brightness 6.7 GHz Methanol Masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 311-312
Author(s):  
Luca Olmi ◽  
Esteban D. Araya ◽  
Jason Armstrong
Keyword(s):  
New Mexico ◽  
Star Formation ◽  
Far Infrared ◽  
Large Array ◽  
Very Large Array ◽  
Early Stages ◽  
Methanol Masers ◽  
Infrared Sources ◽  
Massive Cores

AbstractIn 2014 we conducted a survey for 6.7 GHz methanol masers with the Arecibo Telescope toward far infrared sources selected from the Hi-GAL catalog of massive cores. We found a number of sources with weak 6.7 GHz methanol masers, possibly indicating regions in early stages of star formation. Here we describe the results of follow-up observations that were conducted with the Very Large Array in New Mexico to characterize this new population of “weak” 6.7 GHz methanol masers.

AGN Feedback and its Importance to Galaxy Evolution in the Era of the ngVLA

2018 ◽  
Vol 14 (A30) ◽  
pp. 78-81
Author(s):  
Kristina Nyland
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Angular Resolution ◽  
Galactic Nuclei ◽  
Gas Content ◽  
Large Array ◽  
Very Large Array ◽  
Frequency Coverage ◽  
Evolutionary Role

AbstractEnergetic feedback by Active Galactic Nuclei (AGN) plays an important evolutionary role in the regulation of star formation (SF) on galactic scales. However, the effects of this feedback as a function of redshift and galaxy properties such as mass, environment and cold gas content remain poorly understood. The broad frequency coverage (1 to 116 GHz), high collecting area (about ten times higher than the Karl G. Jansky Very Large Array), and superb angular resolution (maximum baselines of at least a few hundred km) of the proposed next-generation Very Large Array (ngVLA) are uniquely poised to revolutionize our understanding of AGN and their role in galaxy evolution.

scholarly journals Quasi-simultaneous radio and X-ray observations of Aql X-1 : probing low luminosities

2019 ◽  
Vol 492 (2) ◽  
pp. 2858-2871 ◽  
Author(s):  
N V Gusinskaia ◽  
J W T Hessels ◽  
N Degenaar ◽  
A T Deller ◽  
J C A Miller-Jones ◽  
...  
Keyword(s):  
Neutron Star ◽  
Large Array ◽  
Very Large Array ◽  
X Ray ◽  
Upper Limits ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Low X ◽  
Power Law Index ◽  
X Ray Binaries

ABSTRACT Aql X-1 is one of the best-studied neutron star low-mass X-ray binaries. It was previously targeted using quasi-simultaneous radio and X-ray observations during at least seven different accretion outbursts. Such observations allow us to probe the interplay between accretion inflow (X-ray) and jet outflow (radio). Thus far, these combined observations have only covered one order of magnitude in radio and X-ray luminosity range; this means that any potential radio–X-ray luminosity correlation, LR ∝ LXβ, is not well constrained (β ≈ 0.4–0.9, based on various studies) or understood. Here we present quasi-simultaneous Very Large Array and Swift-XRT observations of Aql X-1’s 2016 outburst, with which we probe one order of magnitude fainter in radio and X-ray luminosity compared to previous studies (6 × 1034 erg s−1 < LX <3 × 1035 erg s−1, i.e. the intermediate to low-luminosity regime between outburst peak and quiescence). The resulting radio non-detections indicate that Aql X-1’s radio emission decays more rapidly at low X-ray luminosities than previously assumed – at least during the 2016 outburst. Assuming similar behaviour between outbursts, and combining all available data in the hard X-ray state, this can be modelled as a steep β =$1.17^{+0.30}_{-0.21}$ power-law index or as a sharp radio cut-off at LX ≲ 5 × 1035 erg s−1 (given our deep radio upper limits at X-ray luminosities below this value). We discuss these results in the context of other similar studies.

scholarly journals The Uses of a VLT for Complementing Observations with Radio and Space Telescopes

1984 ◽  
Vol 79 ◽  
pp. 723-724
Author(s):  
Donald N.B. Hall
Keyword(s):  
Electromagnetic Spectrum ◽  
Large Array ◽  
Space Telescopes ◽  
Very Large Array ◽  
X Ray ◽  
International Ultraviolet Explorer ◽  
Infrared Astronomical Satellite ◽  
Astronomical Satellite

It is now evident that major advances in observational sensitivity in other regions of the electromagnetic spectrum invariably lead to heavy demand for complementary observations with existing large (3- to 5-meter) optical/infrared (O/IR) telescopes, and that such observations are often essential to the interpretation and understanding of phenomena revealed by the former. The Einstein X-ray mission, the International Ultraviolet Explorer (IUE), the Very Large Array (VLA) and the recent Infrared Astronomical Satellite (IRAS) are all clear demonstrations of this effect.

scholarly journals A review of H2CO 6cm masers in the Galaxy

2007 ◽  
Vol 3 (S242) ◽  
pp. 110-119 ◽  
Author(s):  
E. Araya ◽  
P. Hofner ◽  
W. M. Goss
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Large Array ◽  
Massive Star Formation ◽  
Very Large Array ◽  
Ongoing Work ◽  
The Galaxy ◽  
Green Bank Telescope

AbstractWe present a review of the field of formaldehyde (H2CO) 6cm masers in the Galaxy. Previous to our ongoing work, H2CO 6cm masers had been detected in the Galaxy only toward three regions: NGC7538 IRS1, Sgr B2, and G29.96–0.02. Current efforts by our group using the Very Large Array, Arecibo, and the Green Bank Telescope have resulted in the detection of four new H2CO 6cm maser regions. We discuss the characteristics of the known H2CO masers and the association of H2CO 6cm masers with very young regions of massive star formation. We also review the current ideas on the pumping mechanism for H2CO 6cm masers.

scholarly journals Is there a cluster in the massive star forming region IRAS 20126+4104?

2015 ◽  
Vol 12 (S316) ◽  
pp. 157-158
Author(s):  
V. A. Montes ◽  
Peter Hofner ◽  
C. Anderson ◽  
V. Rosero
Keyword(s):  
Surface Density ◽  
Massive Star ◽  
Radio Observation ◽  
Large Array ◽  
Very Large Array ◽  
X Ray ◽  
Star Forming ◽  
Continuum Radio

AbstractA Chandra X-ray Observatory ACIS-I observation and a 6 cm continuum radio observation with the Karl G. Jansky Very Large Array (VLA) together with a multiwavelength study in infrared (2MASS and Spitzer) and optical (USNO-B1.0) shows an increasing surface density of X-ray sources toward the massive protostar. There are at least 43 YSOs within 1.2 pc distance from the massive protostar. This number is consistent with typical B-type stars clusters (Lada & Lada 2003).

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