Strong Coupling and Laser Action of Ladder‐Type Oligo(<i>p</i>‐phenylene)s in a Microcavity

Höfner, Michael; Kobin, Björn; Hecht, Stefan; Henneberger, F.

doi:10.1002/cphc.201402492

Cited by 4 publications

(4 citation statements)

References 24 publications

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“…We will comment on two additional resolved and extended radio sources detected in this survey. The first one is 18470-0044 A, which was previously observed by Hofner et al (2011) at 25.5 GHz using the VLA in the C-configuration. This radio source has an offset of 7.…”

Section: Extended Sourcessupporting

confidence: 54%

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Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources

Rosero

Höfner

Kurtz

et al. 2019

ApJ

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In this study we analyze 70 radio continuum sources associated with dust clumps and considered to be candidates for the earliest stages of high-mass star formation. The detection of these sources was reported by Rosero et al. (2016), who found most of them to show weak (<1 mJy) and compact (< 0. 6) radio emission. Herein, we used the observed parameters of these sources to investigate the origin of the radio continuum emission. We found that at least ∼ 30% of these radio detections are most likely ionized jets associated with high-mass protostars, but for the most compact sources we cannot discard the scenario that they represent pressure-confined HII regions. This result is highly relevant for recent theoretical models based on core accretion that predict the first stages of ionization from high-mass stars to be in the form of jets. Additionally, we found that properties such as the radio luminosity as a function of the bolometric luminosity of ionized jets from low and high-mass stars are extremely well-correlated. Our data improve upon previous studies by providing further evidence of a common origin for jets independently of luminosity.

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Section: Extended Sourcessupporting

confidence: 54%

“…This source is among the detections without a clear estimate of its spectral index. However, based on the flux reported by Hofner et al (2011), and our measured flux at 6 cm (see Paper I), this radio source has a flat spectrum, and it is likely an HII region ionized by a B2 ZAMS star.…”

Section: Extended Sourcesmentioning

confidence: 60%

Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources

Rosero

Höfner

Kurtz

et al. 2019

ApJ

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“…This bathochromic shift potentially leads to detuning with respect to the emission of ZnO quantum wells, demanding slightly blueshifted products. [50][51][52] Accordingly, bent iso-L4P-sp2 was synthesized compensating for the spiro-induced red-shift as described above and indeed the absorption maximum of iso-L4P-sp2 is blue-shifted by 4 nm with respect to L4P (Figure 5b, Table 1). The Stokes shift is still small and the fluorescence quantum yield is also about unity.…”

Section: Optical Properties In Solutionmentioning

confidence: 99%

Spiro‐Bridged Ladder‐Type Oligo(para‐phenylene)s: Fine Tuning Solid State Structure and Optical Properties

Kobin

Schwarz

Braun‐Cula

et al. 2017

Adv Funct Materials

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A set of ladder-type quaterphenyls with an incremental number of spiro-bifluorene units in the bridge positions as well as an in-plane bent quaterphenyl carrying all bridges on one and the same side of the ribbon are synthesized and characterized. While spiro-bifluorene substituents lead to bathochromically shifted maxima in the UV-vis absorption spectra, this effect can be compensated by in-plane bending. The influence of different deposition techniques on the solid state structure is analyzed by X-ray diffraction of single crystals obtained by crystallization from solution as well as sublimation. An increasing number of spiro-bifluorene substituents are found to aid thin-film formation.

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“…Protostellar jets from both low-mass and high-mass Young Stellar Objects (YSOs) are known to be ionized, primarily through shocks, during early stages of their evolution (Anglada et al 1998;Hofner et al 2011). In the case of high-mass YSOs, the H-ionizing luminosity increases dramatically when the YSO reaches the main sequence, resulting in prominent ionized winds and/or compact HII regions (Hoare et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Measuring Magnetic Fields from Water Masers Associated with the Synchrotron Protostellar Jet in W3(H2O)

Goddi¹,

Surcis²,

Moscadelli³

2019

Proceedings of 14th European VLBI Network Symposium &Amp; Users Meeting — PoS(EVN2018)

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Context. Magnetic fields are invoked to launch, drive, and shape jets in both low-and high-mass protostars, but observational data on the spatial scales required to assess their role in the protostellar mass-loss process is still scarce. Aims. The Turner-Welch (TW) Object in the W3(OH) high-mass star forming complex drives a synchrotron jet, which is quite exceptional for a high-mass protostar, and is associated with a strongly polarized H 2 O maser source, W3(H 2 O), making it an optimal target to investigate the role of magnetic fields on the innermost scales of protostellar disk-jet systems. Methods. We report full polarimetric VLBA observations of H 2 O masers towards W3(H 2 O). Their linearly polarized emission provides clues on the orientation of the local magnetic field (on the plane of the sky), while the measurement of the Zeeman splitting provides its strength (along the line-of-sight). The linear scales probed by H 2 O masers are tens to hundreds of AU (at the W3(H 2 O) distance, ∼ 2 kpc), inaccessible to other star formation tracers. Results. We identified a total of 148 individual maser features and we measured their physical properties. Out of 148, we measured linear polarization in 34 features, with a fractional percentage varying in the range 0.9%-42%, making W3(H 2 O) the highest polarized H 2 O maser source observed with VLBI known in the Galaxy. The H 2 O masers trace a bipolar, biconical outflow at the center of the synchrotron jet. Although on scales of a few thousand AU the magnetic field inferred from the masers is on average orientated along the flow axis, on smaller scales (10s to 100s of AU), we have revealed a misalignment between the magnetic field and the velocity vectors, which arises from the compression of the field component along the shock front. We also detected circularly polarized emission toward 10 maser features, with a fractional percentage varying in the range 0.2-1.6%. In the gas shocked by the synchrotron jet, we estimate a total field strength in the range ∼100-300 mG (at densities of 10 9 cm −3 ). We conclude that fields of this order of magnitude are expected if the observed polarized water masers emerge behind magnetically supported shocks which, propagating in the W3(H 2 O) hot core (with an initial density of order of 10 7 cm −3 ), compress and enhance the field component perpendicular to the shock velocity (with an initial field strength of a few mG). We constrain the magnetic field strength in the pre-shock circumstellar gas (which is dominated by the component parallel to the flow motion) to at least 10-20 mG (at densities of 10 7 cm −3 ), consistent with previous estimates from a synchrotron jet model and dust polarization measurements. Conclusions. In W3(H 2 O), the magnetic field would evolve from having a dominant component parallel to the outflow velocity in the pre-shock gas, with field strengths of the order of a few tens of mG, to being mainly dominated by the perpendicular component of order of a few hundred of mG in the post-shock gas where the H 2 O m...

show abstract

Strong Coupling and Laser Action of Ladder‐Type Oligo(p‐phenylene)s in a Microcavity

Cited by 4 publications

References 24 publications

Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources

Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources

Spiro‐Bridged Ladder‐Type Oligo(para‐phenylene)s: Fine Tuning Solid State Structure and Optical Properties

Measuring Magnetic Fields from Water Masers Associated with the Synchrotron Protostellar Jet in W3(H2O)

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