Publications (32)
Monitoring of the radio galaxy M87 during a low emission state from 2012 to 2015 with MAGIC
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +188
M87 is one of the closest (z=0.00436) extragalactic sources emitting at very-high-energies (VHE, E > 100 GeV). The aim of this work is to locate the region of the VHE gamma-ray emi…
Discovery of off-axis jet structure of TeV blazar Mrk 501 with mm-VLBI
S. Koyama, M. Kino, M. Giroletti +10
High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar M…
Possible Detection of Apparent Superluminal inward motion in Markarian 421 after the Giant X-ray flare in February, 2010
K. Niinuma, M. Kino, H. Nagai +7
We report on the VLBI follow-up observations using the Japanese VLBI Network (JVN) array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 that occurred in mid-February,…
A Fast Very High Energy -ray Flare from BL Lacertae during a Period of Multiwavelength activity in June 2015
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +163
The mechanisms producing fast variability of the -ray emission in active galactic nuclei are under debate. The MAGIC telescopes detected a fast very high energy (VHE, E G…
Relativistic electrons and magnetic field of the M87 jet on ~ten Schwarzschild radii scale
M. Kino, F. Takahara, K. Hada +1
We explore energy densities of magnetic field and relativistic electrons in the M87 jet. Since the radio core at the jet base is identical to the optically thick surface against sy…
M87 black hole mass and spin estimate through the position of the jet boundary shape break
E. E. Nokhrina, L. I. Gurvits, V. S. Beskin +3
We propose a new method of estimating a mass of a super massive black hole residing in the center of an active galaxy. The active galaxy M87 offers a convenient test case for the m…
A wide and collimated radio jet in 3C 84 on the scale of a few hundred gravitational radii
G. Giovannini, T. Savolainen, M. Orienti +22
Understanding the launching, acceleration, and collimation of jets powered by active galactic nuclei remains an outstanding problem in relativistic astrophysics. This is partly bec…
Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode
J. C. Algaba, M. Balokovic, S. Chandra +738
The nearby elliptical galaxy M87 contains one of the only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (…
X-ray spectral components of the blazar and binary black hole candidate OJ 287 (2005-2020)
S. Komossa, D. Grupe, M. L. Parker +12
We present a comprehensive analysis of all XMM-Newton spectra of OJ 287 spanning 15 years of X-ray spectroscopy of this bright blazar. We also report the latest results from our de…
Discovery of a wandering radio jet base after a large X-ray flare in the blazar Markarian 421
K. Niinuma, M. Kino, A. Doi +3
We investigate the location of the radio jet bases ("radio cores") of blazars in radio images, and their stationarity by means of dense very long baseline interferometry (VLBI) obs…
The kinematic of HST-1 in the jet of M87
M. Giroletti, K. Hada, G. Giovannini +9
Aims: We aim to constrain the structural variations within the HST-1 region downstream of the radio jet of M87, in general as well as in connection to the episodes of activity at v…
Magnetization degree at the jet base of M87 derived from the event horizon telescope data: Testing magnetically driven jet paradigm
M. Kino, F. Takahara, K. Hada +3
We explore the degree of magnetization at the jet base of M87 by using the observational data of the event horizon telescope (EHT) at 230~GHz obtained by Doeleman et al. By utilizi…
Radio and gamma-ray follow-up of the exceptionally high activity state of PKS 1510-089 in 2011
M. Orienti, S. Koyama, F. D'Ammando +24
We investigate the radio and gamma-ray variability of the flat spectrum radio quasar PKS 1510-089 in the time range between 2010 November and 2012 January. In this period the sourc…
Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
J. C. Algaba, J. Anczarski, K. Asada +36
In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are…
Probing Precise Location of Radio Core in TeV Blazar Mrk 501 with VERA at 43 GHz
S. Koyama, M. Kino, A. Doi +13
We investigate the position of the radio core in a blazar by multi-epoch astrometric observations at 43 GHz. Using the VLBI Exploration of Radio Astrometry (VERA), we have conducte…
Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +208
We report multiwavelength observations of the gravitationally lensed blazar QSO B0218+357 in 2016-2020. Optical, X-ray and GeV flares were detected. The contemporaneous MAGIC obser…
On the nature of FRB 150418: clues from European VLBI Network and e-MERLIN observations
M. Giroletti, B. Marcote, M. Garrett +5
We investigate the nature of the compact, and possibly variable nuclear radio source in the centre of WISE J0716-19, the proposed host galaxy of fast radio burst, FRB 150418. We ob…
RadioAstron discovery of a mini-cocoon around the restarted parsec-scale jet in 3C 84
T. Savolainen, G. Giovannini, Y. Y. Kovalev +19
We present RadioAstron space-based very long baseline interferometry (VLBI) observations of the nearby radio galaxy 3C84 (NGC1275) at the centre of the Perseus cluster. The observa…
The 2010 very high energy gamma-ray flare & 10 years of multi-wavelength observations of M 87
The H. E. S. S. Collaboration, :, A. Abramowski +442
Abridged: The giant radio galaxy M 87 with its proximity, famous jet, and very massive black hole provides a unique opportunity to investigate the origin of very high energy (VHE;…
A strong radio brightening at the jet base of M87 during the elevated very-high-energy gamma-ray state in 2012
K. Hada, M. Giroletti, M. Kino +18
The nearby radio galaxy M87 offers a unique opportunity for exploring the connection between gamma-ray production and jet formation at an unprecedented linear resolution. However,…
A strong radio brightening at the jet base of M87 in the period of the elevated TeV gamma-ray state in 2012
K. Hada, M. Giroletti, M. Kino +18
The nearby radio galaxy M87 offers a unique opportunity for exploring the connection between gamma-ray production and jet formation at an unprecedented linear resolution. However,…
Ordered magnetic fields around the 3C 84 central black hole
G. F. Paraschos, J. -Y. Kim, M. Wielgus +279
3C84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region nec…
The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA
S. Issaoun, M. D. Johnson, L. Blackburn +41
The Galactic Center supermassive black hole Sagittarius A* (Sgr A*) is one of the most promising targets to study the dynamics of black hole accretion and outflow via direct imagin…
Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm
E. V. Kravchenko, M. Giroletti, K. Hada +4
We report on high angular resolution polarimetric observations of the nearby radio galaxy M87 using the Very Long Baseline Array at 24 GHz (1.3 cm) and 43 GHz (7 mm) in 2…
A strong radio brightening at the jet base of M87 during the elevated very-high-energy gamma-ray state in 2012
K. Hada, M. Giroletti, M. Kino +18
We report our intensive radio monitoring observations of the jet in M87 with the VLBI Exploration of Radio Astrometry (VERA) and the European VLBI Network (EVN) from February 2011…
Limb-Brightened Jet of 3C 84 Revealed by the 43-GHz Very-Long-Baseline-Array Observation
H. Nagai, T. Haga, G. Giovannini +8
We present a study of sub-pc scale radio structure of the radio galaxy 3C 84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We discover a limb-brightening in…
Evidence of jet-clump interaction: a flip of the radio jet head of 3C~84
M. Kino, K. Wajima, N. Kawakatu +6
Radio jets in active galaxies have been expected to interact with circumnuclear environments in their early phase evolutions. By performing the multi-epoch monitoring observation w…
SYMBA: An end-to-end VLBI synthetic data generation pipeline
F. Roelofs, M. Janssen, I. Natarajan +203
Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to…
Broadband multiwavelength properties of the archetypal blazar 3C 279 during the 2017 Event Horizon Telescope campaign
G. Principe, J. C. Algaba, E. Aviano +529
The archetypal blazar 3C 279 hosts a prominent relativistic jet and exhibits strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Tele…
White Paper on East Asian Vision for mm/submm VLBI: Toward Black Hole Astrophysics down to Angular Resolution of 1~R
K. Asada, M. Kino, M. Honma +35
This White Paper details the intentions and plans of the East Asian Very Long Baseline Interferometry (VLBI) community for pushing the frontiers of millimeter/submillimeter VLBI. T…
Future mmVLBI Research with ALMA: A European vision
R. P. J. Tilanus, T. P. Krichbaum, J. A. Zensus +165
Very long baseline interferometry at millimetre/submillimetre wavelengths (mmVLBI) offers the highest achievable spatial resolution at any wavelength in astronomy. The anticipated…
ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 286
H. Nagai, K. Nakanishi, R. Paladino +6
We present full-polarization observations of the compact, steep-spectrum radio quasar 3C~286 made with the ALMA at 1.3~mm. These are the first full-polarization ALMA observations,…