Research Highlights

Here we show recent research results from the Radio Astronomy/Very-Long-Baseline Interferometry department.

Galaxy evolution studied with the 100-m telescope in Effelsberg

December 23, 2014

A study lead by MPIfR astronomer Mariangela Vitale has probed the importance of active galactic nuclei (AGN) in galaxy evolution.  Models need AGN feedback to explain the observed luminosity in galaxies.   The team studied a sample of radio emitters at distances between 580 Mio lt-yr and 7150 Mio lt-yr, to search for spectral evolution and al ink between optical and radio emission.  Some hints of spectral index flattening in high-metallicity star-forming galaxies, composite galaxies, and Seyferts have been found.  Therefore, galaxies along the sequence are transitioning from the active star-forming calaxies (blue cloud) to the passive elliptical galaxies (red sequence).  This supports the suggestion that AGN shut down star formation and allow transition from one galaxy class to the other.   These results have been published in the last issue of the journal Astronomy & Astrophysics, see the original publication here.

Lightning flashes from a black hole - MAGIC telescopes observe an extremely short, powerful outburst of radiation in Galaxy IC 310

06 November 2014

The radio galaxy IC 310 in the Perseus constellation is approximately 260 million light years away from Earth. Astronomers assume there is a supermassive black hole at its centre. This black hole was the setting for an extremely powerful outburst of gamma rays which was observed by the MAGIC telescopes on La Palma in the Canary Islands. The source exhibited one of the fastest radiation variations which researchers have ever been able to detect in an extragalactic object at these energies.  Ancillary observations from the European VLBI Network reveal a powerful radio jet.  Uwe Bach and Eduardo Ros from the MPI für Radioastronomie are co-authors of this work, published in today's issue of the journal Science.  [more]

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Discovery of a correlation between gamma-ray emission and jet position angle in a blazar

06 November 2014

A team of researchers led by Bindu Rani from the VLBI department of the MPI für Radioastronomie reports for the first time the correlation between gamma-ray emission and the position angle of a jet in a blazar, namely, in the object S5 0716+714.  This implies that the inner jet morphology of AGN jets has a direct connection to the emission of gamma-ray flares.  The observations of this BL Lac objects were carried between August 2008 and September 2013.  The mm-VLBI core radio brightness variations are delayed with respect to the γ-ray flux by 82±32 days.  These results are published in the last issue of the journal Astronomy & Astrophysics, and are part of the successful PhD work of Bindu Rani, presently a postdoctoral fellow at the MPIfR. [more]

The central engine of broad-absorption-line quasars has the same properties for sources with or without a jet

29 September 2014

A study led by Gabriele Bruni from the MPI für Radioastronomie has focused in the study of two samples of broad-absorption-line quasars, aiming for explaining the reasons for the rarity of the radio-loud ones.  The study, carried out with the Telescopio Nazionale Galileo, could show that both classes of objects have the same black-hole mass, the broad-line region radius, and Eddington ratio.  These results are presented in the last issue of Astronomy & Astrophysics. [more]

Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars

August 20, 2014

Study discards possibility that type Ia supernovae might stem from explosions of white dwarfs nourished by normal stars. Were these conclusions to become generalized, type Ia supernovae might no longer serve as “standard candles” to measure astronomical distances.  This work, using the European VLBI Network and the 100-m radio telescope in Effelsberg, was done in collaboration with the MPIfR VLBI Department. [more]
Powerful magnetic fields challenge black holes' pull
Magnetic forces in the environment of Active Galactic Nuclei can match gravitational forces more
Violent gamma-ray outbursts near supermassive black holes
Joint radio and gamma-ray observations allow outbursts in the nuclear regions of active galaxies to be localized more

An armada of telescopes decipher the emission of the powerful galaxy GB 1310+487

April 28, 2014

An international team of astronomers led by K. Sokolovsky and F. Schinzel at the MPIfR has deciphered the broadband emission of the narrow-line gamma-ray-loud AGN GB 1310+487.  Observations include data from the Fermi, AGILE and Swift space telescopes at high frequencies and from the Kanata, NOT, Keck, OAGH, WISE, IRAM 30-m, OVRO 40-m, Effelsberg 100-m, RATAN-600 and the VLBA in the optical-infrared-radio area.  Fermi/LAT observations reveal a strong correlation between the gamma-ray flux and spectral index, being harder at the brighter flux.  The gamma flares occurred before and during a slow rising trend of the radio eission, but no direct association between gamma and radio flares could be stablishesd.  The results are published in Astronomy & Astrophysics.  [more]

A Dance of Black Holes

A Dance of Black Holes

April 22, 2014
Unique pair of supermassive black holes in an ordinary galaxy discovered by XMM-Newton more

Merging galaxies and the size of their cores

February 26, 2014

A study of a sample of 52 double nucleus disk galaxies, led by M. Mezcua and A.P. Lobanov from the MPIfR, derived the luminosity of each of the nuclei and their relative separation from a multi-component photometric fit of the galaxies in the Sloan Digital Sky Survey optical images.  The nuclei in moft of the sources have projected separations smaller than 10000 light-years.  A sample of 19 double nucleus disk galaxies have separations smaller than 3000 light-years and are candidates to be binary active galactic nuclei. [more]

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