A new 3 mm band receiver for the Onsala 20 m antenna

Belitsky, Victor; Lapkin, Igor; Fredrixon, Mathias; Sundin, Erik; Helldner, Leif; Pettersson, Lars; Ferm, Sven-Erik; Pantaleev, Miroslav; Billade, Bhushan; Bergman, P.; Olofsson, A. O. H.; Lerner, M. S.; Strandberg, Magnus; Whale, Mark; Pavolotsky, Alexey; Flygare, Jonas; Olofsson, H.; Conway, J.

doi:10.1051/0004-6361/201425573

Cited by 22 publications

(23 citation statements)

References 6 publications

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“…The same transition of HCN was observed toward comet C/2014 Q2 (Lovejoy) on January 14, 2015, but with the new dual-polarisation, sideband-separating 3 mm receiver system 2 (Belitsky et al 2015) in dual beam-switching mode (DBSW) with secondary beam offset 11 . The system temperature varied between 140-400 K and spectra were recorded with a fast Fourier transform spectrometer at channel separation 12.2 kHz, covering 100 MHz bandwidth.…”

Section: Observations and Data Reductionmentioning

confidence: 60%

HCN observations of comets C/2013 R1 (Lovejoy) and C/2014 Q2 (Lovejoy)

Wirström¹,

Lerner²,

Källström³

et al. 2016

A&A

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HCN J = 1-0 emission from the long-period comet C/2013 R1 (Lovejoy) was observed from the Onsala Space Observatory on multiple occasions during the month before its perihelion passage on December 22, 2013. We report detections for seven different dates, spanning heliocentric distances (R h ) decreasing from 0.94 to 0.82 au. Estimated HCN production rates are generally higher than previously reported for the same time period, but the implied increase in production rate with heliocentric distance, Q HCN ∝ R −3.2 h , represent well the overall documented increase since it was first observed at R h = 1.35. The implied mean HCN abundance relative to water in R1 Lovejoy is 0.2%. We also report on a detection of HCN with the new 3 mm receiver system at Onsala Space Observatory in comet C/2014 Q2 (Lovejoy) on January 14, 2015, when its heliocentric distance was 1.3 au. Relative to comet C/2013 R1 (Lovejoy), the HCN production rate of C/2014 Q2 (Lovejoy) was more than 5 times higher at similar heliocentric distances, and the implied HCN abundance relative to water 0.09%.

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Section: Observations and Data Reductionmentioning

confidence: 60%

HCN observations of comets C/2013 R1 (Lovejoy) and C/2014 Q2 (Lovejoy)

Wirström¹,

Lerner²,

Källström³

et al. 2016

A&A

Self Cite

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“…New molecular line observations were carried out in March 2018 with the 20-m telescope of the OSO (project O2017a-03). We used the 3-mm dual-polarization receiver with a SIS mixer, which has a noise temperature of ∼45-60 K in the 85-116 GHz frequency range (Belitsky et al 2015). Fast Fourier Transform spectrum analyser with a 2.5 GHz bandwidth and a 76 kHz frequency resolution (32768 channels) was used in the observational experiment.…”

Section: New Observationsmentioning

confidence: 99%

“…In this context, some existing models for the long, but finitesized, filaments predict that the fragmentation and collapse can take place at the ends of the filaments (i.e., end-dominated collapse), where the gas has an enhanced acceleration (e.g., Bastien 1983;Burkert & Hartmann 2004;Heitsch et al 2008;Pon et al 2011Pon et al , 2012Clarke & Whitworth 2015). However, observational assessment of such existing numerical simulations is very limited in the literature (e.g., Zernickel et al 2013;Beuther et al 2015;Kainulainen et al 2016;Hacar et al 2016). It requires a promising sample of the filamentary features and the knowledge of molecular gas motion in the direction of these objects (e.g., Kainulainen et al 2016;Contreras et al 2016;Williams et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Observational Signatures of End-dominated Collapse in the S242 Filamentary Structure

Dewangan

Pirogov

Ryabukhina

et al. 2019

ApJ

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We present new CO ( 13 CO(1-0) and C 18 O(1-0)) and CS(2-1) line observations of an elongated filamentary structure (length ∼30 pc) in the star-forming site S242, which were taken with the OSO-20m telescope. One filament's end hosts the S242 H ii region, while the other end contains Planck cold clumps. Several sub-regions are identified in the filament, and are supersonic with Mach number of 2.7-4.0. The study of the dynamical states shows supercritical nature of the sub-regions (except central part), which could not be supported by a combination of thermal and turbulent motions. Young stellar objects are seen toward the entire filament, but more concentrated toward its ends. Dense molecular cores are observed mainly toward the filament ends, and are close to virial equilibrium. Positionvelocity plots trace velocity gradients (∼1 km s −1 pc −1 ) toward both the ends. An oscillatory pattern in velocity is also observed toward the filament, indicating its fragmentation. The collapse timescale of the filament is computed to be ∼3.5 Myr. Using the 13 CO data, the structure function in velocity of the filament is found to be very similar as seen in the Musca cloud for lags ∼1-3 pc, and deviates from the Larson's velocity-size relationship. The observed oscillatory pattern in the structure function at higher lags suggests the existence of large-scale and ordered velocity gradients as well as the fragmentation process through accretion along the filament. Considering all the observed results along with their uncertainties, the S242 filament is a very good example of the end-dominated collapse.

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“…We used a 3 mm dual polarization sideband separating receiver by Belitsky et al (2015) with an FFTS in 2×2. …”

Section: Observationsmentioning

confidence: 99%

Molecular gas in high-mass filament WB673

et al. 2017

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Abstract:We studied the distribution of dense gas in a filamentary molecular cloud containing several dense clumps. The center of the filament is given by the dense clump WB 673. The clumps are high-mass and intermediate-mass starforming regions. We observed CS (2-1), 13 CO (1-0), C 18 O (1-0), and methanol lines at 96 GHz toward WB 673 with the Onsala Space Observatory 20-m telescope. We found CS (2-1) emission in the inter-clump medium so the clumps are physically connected and the whole cloud is indeed a filament. Its total mass is 10 4 M ⊙ and mass-to-length ratio is 360 M ⊙ pc −1 from 13 CO (1-0) data. Mass-to-length ratio for the dense gas is 3.4 − 34 M ⊙ pc −1 from CS (2-1) data. The PV-diagram of the filament is V-shaped. We estimated physical conditions in the molecular gas using methanol lines. Location of the filament on the sky between extended shells suggests that it could be a good example to test theoretical models of formation of the filaments via multiple compression of interstellar gas by supersonic waves.

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A new 3 mm band receiver for the Onsala 20 m antenna

Cited by 22 publications

References 6 publications

HCN observations of comets C/2013 R1 (Lovejoy) and C/2014 Q2 (Lovejoy)

HCN observations of comets C/2013 R1 (Lovejoy) and C/2014 Q2 (Lovejoy)

Observational Signatures of End-dominated Collapse in the S242 Filamentary Structure

Molecular gas in high-mass filament WB673

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