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Using the Atacama Large Millimetre/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA), we observed the Extended Green Object (EGO) G19.01$-$0.03 with sub-arcsecond resolution from 1.05 mm to 5.01 cm wavelengths. Our…

Ring-like distributions of the 6.7 GHz methanol maser spots at milliarcsecond scales represent a family of molecular structures of unknown origin associated with high-mass young stellar objects (HMYSOs). We aim to study G23.657-00.127,…

Astrophysics of Galaxies · Physics 2020-05-06 Anna Bartkiewicz , Alberto Sanna , Marian Szymczak , Luca Moscadelli , Huib Jan van Langevelde , Pawel Wolak

We report the detection of methanol in the disk around the young outbursting star V883 Ori with the Atacama Large Millimeter/submillimeter Array (ALMA). Four transitions are observed with upper level energies ranging between 115 and 459 K.…

For the first time in an extragalactic source, we detect linearly polarized water maser emission associated with the molecular accretion disk of NGC 1068. The position angles of the electric polarization vectors are perpendicular to the…

We report the first sub-arcsecond VLA imaging of 6 GHz continuum, methanol maser, and excited-state hydroxyl maser emission toward the massive protostellar cluster NGC6334I following the recent 2015 outburst in (sub)millimeter continuum…

High-mass protostars are deeply embedded in dust inside their natal cores and are not easily detectable. However, maser emission at centimeter wavelengths, owing to its high brightness, enables us to study gas kinematics in protostars'…

In the early days of methanol maser discoveries the 9(2)-10(1) A+ transition at 23.1 GHz was found to exhibit maser characteristics in the northern star-forming region W3(OH), and probable maser emission in two other sources. Attention…

Astrophysics · Physics 2009-11-10 D. M. Cragg , A. M. Sobolev , J. L. Caswell , S. P. Ellingsen , P. D. Godfrey

W33A is a well-known example of a high-mass young stellar object showing evidence of a circumstellar disc. We revisited the $K$-band NIFS/Gemini North observations of the W33A protostar using principal components analysis tomography and…

Solar and Stellar Astrophysics · Physics 2021-02-17 Felipe Navarete , Augusto Damineli , João E. Steiner , Robert D. Blum

We present 247-GHz molecular line observations of methanol (CH$_3$OH) toward sixteen massive star-forming regions, using the APEX telescope with an angular resolution of $25''$. The sample covers a range of evolutionary states, including…

Observations of Serpens have been performed at the JCMT using Harp-B. Maps over a 4.5'x5.4' region were made in a frequency window around 338 GHz, covering the 7-6 transitions of methanol. Emission is extended over each source, following…

Solar and Stellar Astrophysics · Physics 2015-05-18 L. E. Kristensen , E. F. van Dishoeck , T. A. van Kempen , H. M. Cuppen , C. Brinch , J. K. Jørgensen , M. R. Hogerheijde

A fundamental question about the early evolution of low-mass protostars is when circumstellar disks may form. High angular resolution observations of molecular transitions in the (sub)millimeter wavelength windows make it possible to…

Observational signatures of infalling envelopes and outflowing material in early stages of protostellar evolution, and at small radii from the protostar, are essential to progress in the understanding of the mass-accretion process in star…

Astrophysics of Galaxies · Physics 2015-05-30 C. Goddi , L. Moscadelli , A. Sanna

We report the results of high spatial and spectral resolution integral-field spectroscopy of the central ~3 x 3 arcsec^2 of the active galaxy NGC 1275 (Perseus A), based on observations with the Near-infrared Integral Field Spectrograph…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 J. Scharwaechter , P. J. McGregor , M. A. Dopita , T. L. Beck

We report the result of a systematic methanol observation toward IRAS 19312+1950. The properties of the SiO, H2O and OH masers of this object are consistent with those of mass-losing evolved stars, but some other properties are difficult to…

Solar and Stellar Astrophysics · Physics 2015-08-06 Jun-ichi Nakashima , Andrej M. Sobolev , Svetlana V. Salii , Yong Zhang , Bosco H. K. Yung , Shuji Deguchi

We have used the Australia Telescope Compact Array (ATCA) to make new observations of the 36.2-GHz ($4_{-1}\rightarrow3_0$E) methanol transition toward NGC 4945 and NGC 253. These observations have revealed the presence of new maser…

Astrophysics of Galaxies · Physics 2021-10-20 Tiege McCarthy , Simon Ellingsen , Shari Breen , Maxim Voronkov , Xi Chen , Hai-Hua Qiao

We report Atacama Large Millimeter/submillimeter Array (ALMA) cycle 0 observations of C$^{18}$O ($J=2-1$), SO ($J_N= 6_5-5_4$) and 1.3mm dust continuum toward L1527 IRS, a class 0 solar-type protostar surrounded by an infalling and rotating…

We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding…

Astrophysics of Galaxies · Physics 2015-05-13 J. -F. Desmurs , C. Codella , J. Santiago-Garcia , M. Tafalla , R. Bachiller

The mechanisms leading to the formation of disks around young stellar objects (YSOs) and to the launching of the associated jets are crucial to the understanding of the earliest stages of star and planet formation. HH 212 is a privileged…

The disc around PDS 70 hosts two directly imaged protoplanets in a gap. Previous VLT/SPHERE and recent James Webb Space Telescope/NIRCam observations have hinted at the presence of a third compact source in the same gap at ~13 au, interior…

We have searched for emission from the 36.2 GHz ($4_{-1} \rightarrow 3_0$E) methanol transition towards NGC 4945, using the Australia Telescope Compact Array. 36.2 GHz methanol emission was detected offset south-east from the Galactic…

Astrophysics of Galaxies · Physics 2018-11-21 Tiege P. McCarthy , Simon P. Ellingsen , Xi Chen , Shari L. Breen , Maxim A. Voronkov , Hai-hua Qiao