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We present new JVLA multi-frequency measurements of a set of stars in transition from the post-AGB to the Planetary Nebula phase monitored in the radio range over several years. Clear variability is found for five sources. Their light…

Solar and Stellar Astrophysics · Physics 2017-05-03 L. Cerrigone , G. Umana , C. Trigilio , P. Leto , C. S. Buemi , A. Ingallinera

We present a high sensitivity radio continuum survey at 6 and 1.3$\,$cm using the Karl G. Jansky Very Large Array towards a sample of 58 high-mass star forming regions. Our sample was chosen from dust clumps within infrared dark clouds with…

We present sensitive ($\sigma<10{\rm \mu Jy \, beam^{-1}}$), radio continuum observations using the Australian telescope compact array (ATCA) at frequencies of $6$ and $9$ GHz towards 4 MYSOs. From a previous, less sensitive work, these…

Astrophysics of Galaxies · Physics 2018-09-27 S. J. D. Purser , S. L. Lumsden , M. G. Hoare , N. Cunningham

We conducted very long baseline interferometry (VLBI) observations of five radio-loud narrow-line Seyfert 1 (NLS1) galaxies in milliarcsecond resolutions at 1.7 GHz (18 cm) using the Very Long Baseline Array (VLBA). Significant parsec-scale…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Akihiro Doi , Keiichi Asada , Hiroshi Nagai

We report new Very Large Array high-resolution observations of the radio jet from the outbursting high-mass star S255IR~NIRS3. The images at 6, 10, and 22.2 GHz confirm the existence of a new lobe emerging to the SW and expanding at a mean…

Solar and Stellar Astrophysics · Physics 2024-03-06 R. Cesaroni , L. Moscadelli , A. Caratti o Garatti , J. Eisloeffel , R. Fedriani , R. Neri , T. Ray , A. Sanna , B. Stecklum

Evidence of efficient acceleration of cosmic rays in massive young stellar objects has been recently reported. Among these massive protostars, S255 NIRS 3 for which extreme flaring events associated with radio jets have been detected, is…

High Energy Astrophysical Phenomena · Physics 2023-05-31 Emma de Oña Wilhelmi , Rubén López-Coto , Yang Su

We report the results of a 15 GHz (2 cm) multi-epoch VLBA program, begun in 1994 to study the outflow in radio jets ejected from quasars and active galaxies. The observed flow of 208 distinct features measured in 110 quasars, active…

We have used the VLBA at 5 GHz to observe all galaxies with nuclear radio flux densities above 3.5 mJy found in a VLA survey at 15 GHz of a sample of nearby LINER galaxies. All galaxies were detected revealing high brightness temperature…

Astrophysics · Physics 2009-10-31 Heino Falcke , Neil M. Nagar , Andrew S. Wilson , James S. Ulvestad

We report new Karl G. Jansky Very Large Array (JVLA), 0$"$.5 angular resolution observations of linearly polarized continuum emission at 6.9 mm, towards the Class 0 young stellar object (YSO) NGC1333 IRAS4A. This target source is a…

We carried out multiwavelength (0.7-5 cm), multiepoch (1994-2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio…

We present radio continuum observations at 7 mm made using the Very Large Array towards three massive star forming regions thought to be in very early stages of evolution selected from the sample of Sridharan et al. (2002). Emission was…

Astrophysics · Physics 2009-06-23 Guido Garay , Luis F. Rodriguez , Itziar de Gregorio-Monsalvo

Context. Recent observations of the massive young stellar object S255 NIRS 3 have revealed a large increase in both methanol maser flux density and IR emission, which have been interpreted as the result of an accretion outburst, possibly…

Solar and Stellar Astrophysics · Physics 2018-05-09 R. Cesaroni , L. Moscadelli , R. Neri , A. Sanna , A. Caratti o Garatti , J. Eisloeffel , B. Stecklum , T. Ray , C. M. Walmsley

While most protostellar jets present free-free emission at radio wavelengths, synchrotron emission has been also proposed to be present in a handful of these objects. The presence of non-thermal emission has been inferred by negative…

We report Very Large Array (VLA) observations in the Q-band toward 10 ionized jet candidates to search for SiO emission, a well-known shocked gas tracer. We detected 7 mm continuum counterparts toward 90% of the jet candidates. In most…

Astrophysics of Galaxies · Physics 2023-02-01 Tatiana M. Rodriguez , Peter Hofner , Isaac Edelman , Esteban D. Araya , Viviana Rosero

We present high resolution (arcsecond or better) observations made with the Karl G. Jansky Very Large Array of 123 radio-loud quasars with redshifts in the range $2.5 \leq z \leq 5.28$ that form a complete flux limited sample ($\geq 70$ mJy…

Astrophysics of Galaxies · Physics 2014-06-19 Doug B. Gobeille , John F. C. Wardle , C. C. Cheung

Centimeter continuum observations of protostellar jets have revealed the presence of knots of shocked gas where the flux density decreases with frequency. This spectrum is characteristic of nonthermal synchrotron radiation and implies the…

Solar and Stellar Astrophysics · Physics 2019-03-06 A. Sanna , L. Moscadelli , C. Goddi , M. Beltran , C. L. Brogan , A. Caratti o Garatti , C. Carrasco-Gonzalez , T. R. Hunter , F. Massi , M. Padovani

We present high-resolution observations made with the Very Large Array (VLA) in its A configuration at frequencies between 5 and 43 GHz of a sample of five massive young stellar objects (YSOs): LkHa101, NGC2024-IRS2, S106-IR, W75N and…

Astrophysics · Physics 2009-11-13 A. G. Gibb , M. G. Hoare

The Jansky Very Large Array was used to observe 121 magnetic cataclysmic variables (MCVs). We report radio detections of 19 stars. Fourteen are new radio sources, increasing the number of MCVs that are radio sources by more than twofold,…

Solar and Stellar Astrophysics · Physics 2017-12-06 Paul E. Barrett , Christopher Dieck , Anthony J. Beasley , Kulinder P. Singh , Paul A. Mason

We report on the discovery of one of the most extreme cases of high-frequency radio variability ever measured in active galactic nuclei (AGN), observed on timescales of days and exhibiting variability amplitudes of three to four orders of…

We present results from a combined radio polarization and emission line study of five type 2 quasars at $z<0.2$ with the Karl G. Jansky Very Large Array (VLA) B-array at 5 GHz and Hubble Space Telescope (HST) [O III] observations. These…

Astrophysics of Galaxies · Physics 2022-07-19 Silpa Sasikumar , P. Kharb , C. M. Harrison , A. Girdhar , D. Mukherjee , V. Mainieri , M. E. Jarvis