Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz

  title={Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz},
  author={Eskil Varenius and John Conway and Iv'an Mart'i-Vidal and R. J. Beswick and Adam T. Deller and Olaf Wucknitz and N. Jackson and Bj{\"o}rn Adebahr and Miguel 'Angel P'erez-Torres and K. T. Chy.zy and Tobia D. Carozzi and Javier Mold'on and Susanne Aalto and Rainer Beck and Philip N. Best and R. J. Dettmar and Wim van Driel and Gianfranco Brunetti and Marcus Bruggen and Marijke Haverkorn and George Heald and C. Horellou and Matt J. Jarvis and Leah K. Morabito and George K. Miley and H. J. A. Rottgering and M. Carmen Toribio and Glenn J. White},
  journal={Astronomy and Astrophysics},
Context. The nuclear starburst in the nearby galaxy M82 provides an excellent laboratory for understanding the physics of star formation. This galaxy has been extensively observed in the past, revealing tens of radio-bright compact objects embedded in a di use free-free absorbing medium. Our understanding of the structure and physics of this medium in M82 can be greatly improved by high-resolution images at low frequencies where the e ects of free-free absorption are most prominent. Aims. The… 

Figures and Tables from this paper

Subarcsecond international LOFAR radio images of Arp 220 at 150 MHz. A kpc-scale star forming disk surrounding nuclei with shocked outflows

Context. Arp 220 is the prototypical ultra luminous infrared galaxy (ULIRG). Despite extensive studies, the structure at MHz-frequencies has remained unknown because of limits in spatial resolution.

LOFAR VLBI Studies at 55 MHz of 4C 43.15, a z=2.4 Radio Galaxy

The correlation between radio spectral index and redshift has been exploited to discover high-redshift radio galaxies, but its underlying cause is unclear. It is crucial to characterize the particle

Investigation of the cosmic ray population and magnetic field strength in the halo of NGC 891

Context. Cosmic rays and magnetic fields play an important role for the formation and dynamics of gaseous halos of galaxies. Aims. Low-frequency radio continuum observations of edge-on galaxies are

LOFAR MSSS: Flattening low-frequency radio continuum spectra of nearby galaxies

Aims. The shape of low-frequency radio continuum spectra of normal galaxies is not well understood, the key question being the role of physical processes such as thermal absorption in shaping them.

LOFAR observations of X-ray cavity systems

We present LOFAR observations at 120–168 MHz of 42 systems with possible X-ray cavities in their hot atmosphere, of which 17 are groups or ellipticals, 19 are nearby clusters (z < 0.3), and six are

CHANG-ES. XX. High-resolution Radio Continuum Images of Edge-on Galaxies and Their AGNs: Data Release 3

The CHANG-ES galaxy sample consists of 35 nearby edge-on galaxies that have been observed using the VLA at 1.6 and 6.0 GHz. Here we present the third data release of our sample, namely, the B

The LOFAR Two-metre Sky Survey. I. Survey description and preliminary data release

The LOFAR Two-metre Sky Survey (LoTSS) is a deep 120-168 MHz imaging survey that will eventually cover the entire northern sky. Each of the 3170 pointings will be observed for 8 h, which, at most

LOFAR observations of the XMM-LSS field

We present observations of the XMM Large-Scale Structure (XMM-LSS) field observed with the LOw Frequency ARray (LOFAR) at 120–168 MHz. Centred at a J2000 declination of −4.5°, this is a challenging

The LOFAR long baseline snapshot calibrator survey

The observed density of satisfactory delay calibrator sources means that observations with international LOFAR should be possible at virtually any point in the sky provided that a fast and efficient search is conducted prior to the observation to identify the best calibrator.

Reaching small scales with low-frequency imaging: applications to the Dark Ages

What values of k can be reached for the Low-Frequency Array (LOFAR) are investigated, and it is found that LOFAR is approximately five orders of magnitude away from the desired sensitivity, for 10 years of integration time.



Deep MERLIN 5 GHz radio imaging of supernova remnants in the M82 starburst

The results of an extremely deep, 8-d long observation of the central kpc of the nearby starburst galaxy M82 using Multi-Element Radio Linked Interferometer Network (MERLIN) at 5 GHz are presented.


We have used MERLIN at 408 MHz to image the central starburst region ofM82 with a resolution of 0.5 arcsec. We detect ~20 supernova remnants at this frequency, which is a much smaller number than we

Radio Spectra of Selected Compact Sources in the Nucleus of M82

We have determined detailed radio spectra for 26 compact sources in the starburst nucleus of M82, between 74 and 1.3 cm. Seventeen show low-frequency turnovers. One other has a thermal emission

Detection of jet precession in the active nucleus of M 81

We report on very-long-baseline-interferometry (VLBI) monitoring observations of the low-luminosity active galactic nucleus (LLAGN) in the galaxy M 81 at the frequencies of 1.7, 2.3, 5.0, and 8.4

Interpreting the low-frequency radio spectra of starburst galaxies: a pudding of Strömgren spheres

The low frequency radio emission of starburst galaxies is informative, but it can be absorbed in several ways. Most importantly, starburst galaxies are home to many H II regions, whose free-free

Compact starbursts in ultraluminous infrared galaxies

The 40 ultraluminous galaxies in the IRAS Bright Galaxy Sample of sources stronger than S = 5.24 Jy at lambda = 60 microns were mapped with approximately 0.25 arcsec resolution at 8.44 GHz.

M 82 – A radio continuum and polarisation study - I. Data reduction and cosmic ray propagation

The potential role of magnetic fields and cosmic ray propagation for feedback processes in the early Universe can be probed by studies of local starburst counterparts with an equivalent

A Wide-Area VLA Continuum Survey near the Galactic Center at 6 and 20 cm Wavelengths

We describe the results of a millijansky sensitivity VLA survey of roughly 1 deg2 near the Galactic center at 6 and 20 cm. Catalogs of compact and filamentary structures are given and compared to

Wide-field Global VLBI and MERLIN combined monitoring of supernova remnants in M82

From a combination of Multi-Element Radio-Linked Interferometer Network (MERLIN) and global Very Long Baseline Interferometry (VLBI) observations of the starburst galaxy M82, images of 36 discrete

The Location of the Core in M81

We report on VLBI observations of M81*, the northeast-southwest oriented nuclear core-jet source of the spiral galaxy M81, at five different frequencies between 1.7 and 14.8 GHz. By phase referencing