A5022774707- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Geomagnetism and Paleomagnetism Studies
- Superconducting and THz Device Technology
- Microwave Engineering and Waveguides
- Antenna Design and Optimization
- Pulsars and Gravitational Waves Research
- Radio Wave Propagation Studies
- Magnetic Bearings and Levitation Dynamics
- Astro and Planetary Science
- Spectroscopy and Laser Applications
- Historical Geography and Cartography
Max Planck Institute for Radio Astronomy
2013-2022
Max Planck Society
2006-2019
Lomonosov Moscow State University
2010
Institute of Continuous Media Mechanics
2010
University of Cologne
2010
Optica
2009
Max Planck Institute for Extraterrestrial Physics
2009
Universidad Nacional Autónoma de México
2009
TU Dortmund University
2005
<i>Aims. <i/>This paper describes the Heterodyne Instrument for Far-Infrared (HIFI) that was launched onboard ESA's <i>Herschel<i/> Space Observatory in May 2009. <i>Methods. <i/>The instrument is a set of 7 heterodyne receivers are electronically tuneable, covering 480–1250 GHz with SIS mixers and 1410–1910 range hot electron bolometer (HEB) mixers. The local oscillator (LO) subsystem comprises Ka-band synthesizer followed by 14 chains frequency multipliers 2 each band. A pair...
The commonly used classical equipartition or minimum-energy estimate of total magnetic fields strengths from radio synchrotron intensities is limited practical use because it based on the hardly known ratio K energies cosmic ray protons and electrons also has inherent problems. We present a revised formula, using number density for which we give estimates. For particle acceleration in strong shocks about 40 increases with decreasing shock strength. Our field strength gives larger values than...
Aims. In the context of models galaxy formation and evolution, we investigate cosmological evolution large- small-scale magnetic fields inside galaxies.
We study the spectral energy distribution (SED) of radio continuum emission from KINGFISH sample nearby galaxies to understand energetics and origin this emission. Effelsberg multi-wavelength observations at 1.4GHz, 4.8GHz, 8.5GHz, 10.5GHz combined with archive data allow us, for first time, determine mid-radio (1-10 GHz, MRC) bolometric luminosities further present calibration relations vs. monochromatic luminosities. The 1-10 GHz SED is fitted using a Bayesian Markov Chain Monte Carlo...
We present the first part of observations made for Continuum Halos in Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim CHANG-ES project is to study and characterize nature radio halos, their prevalence as well magnetic fields, cosmic rays illuminating these fields. This paper reports with compact D configuration Karl G. Jansky Very Large Array (VLA) sample 35 nearby edge-on galaxies CHANG-ES. With new wide bandwidth capabilities VLA, unprecedented sensitivity was achieved all...
The diffusive and convective CR transport in NGC 253 from the disk into halo is investigated using local bulk speed. connection between galactic wind outlined. We observed with VLA at lambda 6.2 cm a mosaic 15 pointings. missing zero-spacing flux density of was filled observations 100-m Effelsberg telescope. also obtained new 3.6 map reproduced maps 20 90 cm. find thin thick radio exponential scaleheights 0.3 kpc 1.7 equipartition total magnetic field strength 7 micro G 18 remarkably high....
We derive the distribution of synchrotron spectral index across NGC 6946 and investigate correlation between radio continuum (synchrotron) far-infrared (FIR) emission using KINGFISH Herschel-PACS SPIRE data. The radio-FIR is studied as a function star formation rate, magnetic field strength, radiation total gas surface density. follows both star-forming regions so-called arms present in inter-arm regions. steepest along (αn ~ 1), while it flat places giant Hii center galaxy 0.6−0.7). map αn...
The vertical halo scale height is a crucial parameter to understand the transport of cosmic-ray electrons (CRE) and their energy loss mechanisms in spiral galaxies. Until now, radio could only be determined for few edge-on galaxies because missing sensitivity at high resolution. We developed sophisticated method determination With this we heights radial lengths sample 13 from CHANG-ES continuum survey two frequency bands. average value are 1.1 +/- 0.3kpc C-band 1.4 0.7kpc L-band. From...
We present radio continuum maps of 12 nearby ($D\leq 27~\rm Mpc$), edge-on ($i\geq 76^{\circ}$), late-type spiral galaxies mostly at $1.4$ and 5 GHz, observed with the Australia Telescope Compact Array, Very Large Westerbork Synthesis Radio Telescope, Effelsberg 100-m Parkes 64-m telescopes. All show clear evidence haloes, including first detection in Magellanic-type galaxy NGC 55. In 11 galaxies, we find a thin thick disc that can be better fitted by exponential rather than Gaussian...
Context. The magnetic field in spiral galaxies is known to have a large-scale structure along the galactic disk and observed as X-shaped halo of some galaxies. While can be well explained by dynamo action, 3-dimensional its physical nature still unclear. Aims. As first steps towards understanding fields, we want clarify whether wide-spread pattern halos these fields are just turbulent ordered compression or shear (anisotropic fields), regular structure. Methods. analysis Faraday rotation...
Context. Constraints on the origin and propagation of cosmic rays can be achieved by studying variation in spectral index synchrotron emission across external galaxies.
Aims.We investigate the energy sources of infrared (IR) emission and their relation to radio continuum at various spatial scales within Scd galaxy M 33.
<i>Context. <i/>There are several edge-on galaxies with a known magnetic field structure in their halo. A vertical significantly enhances the cosmic-ray transport from disk into This could explain existence of observed radio halos.<i>Aims. <i/>We NGC 253 that possesses one brightest halos discovered so far. Since this galaxy is not exactly () has to be modeled and subtracted observations order study halo.<i>Methods. used continuum polarimetry VLA D-configuration Effelsberg 100-m telescope....
The potential role of magnetic fields and cosmic ray propagation for feedback processes in the early Universe can be probed by studies local starburst counterparts with an equivalent star-formation rate. Archival data from WSRT was reduced a new calibration technique introduced to reach high dynamic ranges needed complex source morphology M82. This combined archival VLA data, yielding total power maps at 3cm, 6cm, 22cm 92cm. shows confinement emission wavelengths 3/6cm core region largely...
We present 1D cosmic ray transport models, numerically solving equations of pure advection and diffusion for the electrons calculating synchrotron emission spectra. find that exponential halo magnetic field distributions leads to approximately radio continuum intensity profiles, whereas profiles can be better approximated by a Gaussian function. Accordingly, vertical spectral are linear, they 'parabolic' shape. compare our models with deep Australia Telescope Compact Array observations two...
Aims. We study the magnetic field structure, strength, and energy density in Scd galaxy M 33.
We introduce a new survey to map the radio continuum halos of sample 35 edge-on spiral galaxies at 1.5 GHz and 6 in all polarization products. The is exploiting wide bandwidth capabilities Karl G. Jansky Very Large Array (i.e. Expanded Array, or EVLA) variety array configurations (B, C, D) order compile most comprehensive data set yet obtained for study halo properties. This first include In this paper, we outline scientific motivation survey, specific science goals, expected improvements...
Context. Magnetic fields are good tracers of gas compression by shock waves in the interstellar medium. These can be caused interaction star-formation driven outflows from individual star formation sites as described chimney model. Integration along line-of-sight and cosmic-ray diffusion may hamper detection compressed magnetic many cases.
We present the first results from Continuum Halos in Nearby Galaxies—an EVLA Survey (CHANG-ES), a new survey of 35 edge-on galaxies to search for both in-disk and extraplanar radio continuum emission. CHANG-ES is exploiting wide-band, multi-channel capabilities Karl G. Jansky Very Large Array (i.e., Expanded or EVLA) with observations two bands centered at 1.5 6 GHz variety array configurations full polarization. The motivation science case are presented companion paper (Paper I). These...
We have observed the Virgo Cluster spiral galaxy, NGC~4845, at 1.6 and 6 GHz using Karl G. Jansky Very Large Array, as part of `Continuum Halos in Nearby Galaxies -- an EVLA Survey' (CHANG-ES). The source consists a bright unresolved core with surrounding weak central disk (1.8 kpc diameter). is variable over month time scale CHANG-ES data has increased by factor $\approx$ since 1995. wide bandwidths allowed us to determine spectral evolution this which peaks {\it between} (it...
How a galaxy regulates its supernovae (SNe) energy into different interstellar/circumgalactic medium components strongly affects evolution. Based on the JVLA D-configuration C- (6 GHz) and L-band (1.6 continuum observations, we perform statistical analysis comparing multiwavelength properties of Continuum Haloes in Nearby Galaxies – an EVLA Survey galaxies. The high-quality data edge-on orientation enable us for first time to include halo budget complete radio-flux-limited sample. We find...
Low-frequency radio continuum observations of edge-on galaxies are ideal to study cosmic-ray electrons (CREs) in halos via synchrotron emission and measure magnetic field strengths. We obtained new the spiral galaxy NGC 891 at 129-163 MHz with LOw Frequency ARray (LOFAR) 13-18 GHz Arcminute Microkelvin Imager (AMI) combine them recent high-resolution Very Large Array (VLA) 1-2 GHz, enabling us over two orders magnitude frequency. The spectrum integrated nonthermal flux density can be fitted...