German Jurisprudence and Ethics

Ostrowski, Marius S.

doi:10.1007/978-3-319-70781-5_23

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Researchers have examined local variations of SNR spectral indices (especially flattening) in molecular clouds and several theories have been proposed to understand the emission mechanisms. These include second-order fermi acceleration in the turbulent medium near the shock and momentum diffusion (e.g., Schlickeiser & Fuerst 1989;Ostrowski 1999). In the following sections, we provide details of supporting evidence regarding the SNR.…”

Section: Spectral Tomographymentioning

confidence: 99%

Non-thermal emission from massive star-forming regions: a possible SNR candidate G351.7–1.2?

Veena

Vig

Sebastian

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present low frequency wide band observations (300 − 500 MHz) of the star forming complex G351.7-1.2 using upgraded Giant Metrewave Radio Telescope (uGMRT), India. Combining this with the optical, infrared and submillimeter data, we analyse the large scale diffuse radio emission associated with the region that exhibits a broken shell morphology. The spectral index of the emission in the shell is −0.8, indicating non-thermal emission. Hα emission that mimics the morphology of the radio shell on a smaller scale is also detected here. Based on the non-thermal emission from the radio shell and the presence of its optical counterpart, we classify G351.7-1.2 as a candidate SNR. A γ-ray source detected by Fermi LAT (1FGLJ1729.1-3641c) is located towards the south-west of the radio shell and could have a possible origin in the interaction between high velocity particles from the SNR and the ambient molecular cloud.

show abstract

Section: Spectral Tomographymentioning

confidence: 99%

Non-thermal emission from massive star-forming regions: a possible SNR candidate G351.7–1.2?

Veena

Vig

Sebastian

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…in the radiative phase) emitting synchrotron radiation (Chevalier 1999). Another possibility is that electrons are accelerated through second order Fermi acceleration (Ostrowski 1999).…”

Section: Synchrotron Emission From the Shocked Molecular Cloudmentioning

confidence: 99%

Investigating Particle Acceleration in Protostellar Jets: The Triple Radio Continuum Source in Serpens

Rodríguez-Kamenetzky

Carrasco-González²,

Araudo

et al. 2016

ApJ

View full text Add to dashboard Cite

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 spectral indices at centimeter wavelengths. In one case (the HH 80-81 jet arising from a massive protostar), its synchrotron nature was confirmed by the detection of linearly polarized radio emission. One of the main consequences of these results is that synchrotron emission implies the presence of relativistic particles among the non-relativistic material of these jets. Therefore, an acceleration mechanism should be taking place. The most probable scenario is that particles are accelerated when the jets strongly impact against the dense envelope surrounding the protostar. Here, we present an analysis of radio observations obtained with the Very Large Array of the Triple Radio Source in the Serpens star-forming region. This object is known to be a radio jet arising from an intermediate-mass protostar. It is also one of the first protostellar jets where the presence of non-thermal emission was proposed. We analysed the dynamics of the jet as well as the nature of the emission and discuss these issues in the context of the physical parameters of the jet and the particle acceleration phenomenon.

show abstract

“…Furthermore, because the spectral index of G5.9+3.1 is less than the value of 0.5 predicted by test-particle DSA, the so-called equipartition calculation, derived for α ≥ 0.5, cannot be used for magnetic field estimation for this SNR (Arbutina et al 2012Urošević, Pavlović & Arbutina 2018). Bearing in mind the calculated parameter uncertainty, spectral indices less than 0.5 can be explained by a significant contribution of the stochastic Fermi acceleration (see Ostrowski 1999;Ostrowski & Schlickeiser 1993;Schlickeiser & Fürst 1989;Onić 2013).…”

Section: Integrated Radio Continuum Spectrum Of the Supernova Remnantmentioning

confidence: 96%

Murchison Widefield Array and XMM-Newton observations of the Galactic supernova remnant G5.9+3.1

Onić

Filipović

Bojičić

et al. 2019

A&A

View full text Add to dashboard Cite

Aims. In this paper we discuss the radio continuum and X-ray properties of the so-far poorly studied Galactic supernova remnant (SNR) G5.9+3.1. Methods. We present the radio spectral energy distribution (SED) of the Galactic SNR G5.9+3.1 obtained with the Murchison Widefield Array (MWA). Combining these new observations with the surveys at other radio continuum frequencies, we discuss the integrated radio continuum spectrum of this particular remnant. We have also analyzed an archival XMM-Newton observation, which represents the first detection of X-ray emission from this remnant. Results. The SNR SED is very well explained by a simple power-law relation. The synchrotron radio spectral index of G5.9+3.1 is estimated to be 0.42±0.03 and the integrated flux density at 1 GHz to be around 2.7 Jy. Furthermore, we propose that the identified point radio source, located centrally inside the SNR shell, is most probably a compact remnant of the supernova explosion. The shelllike X-ray morphology of G5.9+3.1 as revealed by XMM-Newton broadly matches the spatial distribution of the radio emission, where the radio-bright eastern and western rims are also readily detected in the X-ray while the radio-weak northern and southern rims are weak or absent in the X-ray. Extracted MOS1+MOS2+PN spectra from the whole SNR as well as the north, east, and west rims of the SNR are fit successfully with an optically thin thermal plasma model in collisional ionization equilibrium with a column density N H ∼ 0.80 × 10 22 cm −2 and fitted temperatures spanning the range kT ∼ 0.14 − 0.23 keV for all of the regions. The derived electron number densities n e for the whole SNR and the rims are also roughly comparable (ranging from ∼ 0.20 f −1/2 cm −3 to ∼ 0.40 f −1/2 cm −3 , where f is the volume filling factor). We also estimate the swept-up mass of the X-ray emitting plasma associated with G5.9+3.1 to be ∼ 46 f −1/2 M ⊙ .

show abstract

German Jurisprudence and Ethics

Cited by 3 publications

References 0 publications

Non-thermal emission from massive star-forming regions: a possible SNR candidate G351.7–1.2?

Non-thermal emission from massive star-forming regions: a possible SNR candidate G351.7–1.2?

Investigating Particle Acceleration in Protostellar Jets: The Triple Radio Continuum Source in Serpens

Murchison Widefield Array and XMM-Newton observations of the Galactic supernova remnant G5.9+3.1

Contact Info

Product

Resources

About