Exploring the variability of the flat spectrum radio source 1633+382

Colloquium

Astronomy Colloquium (2017 Spring Semester)

* Date: Jun 08
* Speaker: Juan Carlos Algaba Marcos (KASI)
* Title: Exploring the variability of the flat spectrum radio source 1633+382
* Abstract

We present multi-frequency simultaneous VLBI radio observations of the flat spectrum radio quasar 1633+382 (4C 38.41) as part of the interferometric monitoring of gamma-ray bright active galactic nuclei (iMOGABA) program combined with additional observations in radio, optical, X-rays and gamma-rays carried out between the period 2012 March – 2015 August. The monitoring of this source reveals a significant increase in its activity in the radio bands, which correlates with other bands from sub-millimeter to gamma-rays. The epochs of the maxima for the two largest $gamma-$ray flares seem to coincide with the ejection of two respective new VLBI components. The evolution of the flares probes the adiabatic losses in agreement with the shock-in-jet model. Derived synchrotron self absorption magnetic fields, of the order of 0.1~mG, do not seem to dramatically change during the flares, and are much smaller than the estimated equipartition magnetic fields, indicating that the source of the flare may be associated with a particle dominated emitting region. This is consistent with considerations suggesting that this region may be located near but downstream the acceleration and collimation region.

Date	Speaker	Title	Remarks
Mar 02	Chris Belczynski (Warsaw University Observatory)	The ongoing LIGO search for gravitational-waves: BH-BH modeling
Mar 09	Jeongwoo Lee (Institute for Space-Earth Environmental Research, Nagoya University)	When the Sun’s Coronal Tail Wags Its Photospheric Dog
Mar 16	Hongjun An (CBNU)	High-energy astrophysics in the X-ray and GeV energies
Mar 23	KASI ALMA Group	ALMA Town Meeting
Mar 30	Ken Chen (NAOJ, Japan)	Lighting up the Universe with Extreme Supernovae
Apr 06	Guangyao Zhao (KASI)	Multi-frequency mm-VLBI observations of AGNs with KVN
Apr 11	Tarun Souradeep (IUCAA Pune, India)	Rugged but enigmatic post-Planck Cosmos	Tuesday
Apr 20	Tugca Sener (KASI)	Hot subdwarf stars in binaries
Apr 27	Benjamin L’Huillier (KASI)	Numerical simulations of structure formation: LCDM and beyond
May 04	TBD	TBD
May 11	Thiem Hoang (KASI)	New Insights into the Role and Importance of Interstellar Nanoparticles
May 18	Ho Jung Paik (U Maryland)	Superconducting Gravitational Wave Detector For Observation in Infrasound Frequency Band
May 23	Kwang-Ho Park (Georgia Tech)	Feedback-regulated fueling of massive black holes	Tuesday
May 25	Pei-Ying Hsieh (ASIAA)	The molecular gas feeding the Galactic center – an excellent laboratory to understand supermassive black hole feeding
May 30	Andreas Schulze (NAOJ)	New constraints on the black hole spin in radio-loud quasars	Tuesday
Jun 01	Mijin Yoon (Yonsei University)	Testing the statistical isotropy using dipolar modulation in galaxy number counts
Jun 08	Juan Carlos Algaba Marcos (KASI)	Exploring the variability of the flat spectrum radio source 1633+382
Jun 16	Takahiro Hiroi (Brown University)	Asteroid-Meteorite Reflectance Spectroscopy, Space Weathering, and Hayabusa Missions	Friday

2017 Spring semester detail