BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:X-ray binaries and stellar-mass black holes DTSTART;VALUE=DATE-TIME:20240904T090000Z DTEND;VALUE=DATE-TIME:20240904T093000Z DTSTAMP;VALUE=DATE-TIME:20260420T183853Z UID:indico-contribution-11-0-71@cern.ch DESCRIPTION:Speakers: Prof. MILLER-JONES\, James (International Centre for Radio Astronomy Research - Curtin University)\nX-ray binaries provide nea rby laboratories to study the launching and evolution of relativistic jets on human timescales. High angular resolution VLBI observations are critic al in determining the motions of these jets\, allowing us to track them ba ck to their launch point and determine an ejection time. This can be compa red with the contemporaneous X-ray behaviour to determine the causal conne ction between the changing geometry of the accretion flow and the evolving properties of the jets. However\, the rapid variability of the jets in bo th brightness and morphology can in some cases violate the fundamental ass umptions of aperture synthesis\, precluding high-precision measurements of the jet properties. Recent algorithmic advances are allowing us to overco me these challenges\, providing a wealth of new information on the propert ies of the jets. In this talk I will give an overview of recent progress i n this field\, explaining what we can learn from VLBI studies at different stages of an X-ray binary outburst. I will also discuss the use of X-ray binary jets as astrometric probes\, allowing us to measure the proper moti ons and parallaxes of these systems. Together with systemic radial velocit ies determined from the optical band\, these measurements can be used to c alculate the binary's motion through the Galaxy\, and hence place constrai nts on the formation of their black holes.\n\nhttps://events.mpifr-bonn.mp g.de/indico/event/371/session/11/contribution/71 LOCATION:CJD Bonn Castell URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/71 END:VEVENT BEGIN:VEVENT SUMMARY:Discovering the quiet side of Black Hole X-ray Binaries: A Systema tic Search in Radio Surveys DTSTART;VALUE=DATE-TIME:20240904T093000Z DTEND;VALUE=DATE-TIME:20240904T094500Z DTSTAMP;VALUE=DATE-TIME:20260420T183853Z UID:indico-contribution-11-0-88@cern.ch DESCRIPTION:Speakers: Dr. ATRI\, Pikky (ASTRON)\nBlack hole X-ray binaries (BHXBs) are stellar-mass black holes in binary systems with stars\, servi ng as laboratories for studying various astrophysical phenomena such as ac cretion-outflow mechanisms\, jet launching processes\, and binary evolutio n. With approximately 70 known systems in our Galaxy and 2-3 new discoveri es annually\, most studies focus on systems detected during outbursts when sudden changes in accretion rates illuminate them across the electromagne tic spectrum. This biases our understanding of BHXB behavior toward system s undergoing outbursts\, whereas it is known that the systems spend most o f their life in a quiescent\, quiet state. In this talk\, I'll demonstrate the effectiveness of measuring proper motions of variable radio sources f rom wide-field surveys to select compact Galactic targets and find potenti al quiescent BHXB candidates or other unknown radio transients. Using the Very Long Baseline Array (VLBA)\, we observed 33 highly variable radio sou rces\, detecting 14 on one or more epochs\, with no optical\, X-ray or inf rared counterparts found. Among the detected targets\, we identified five Galactic candidates for quiescent BHXBs\, while only one such system had b een known prior to this study. This illustrates the potential of systemati c searches in radio surveys\, archival and upcoming\, to expand the popula tion of quiescent BHXBs and discover new types of exotic radio transients. \n\nhttps://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/88 LOCATION:CJD Bonn Castell URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/88 END:VEVENT BEGIN:VEVENT SUMMARY:Capturing the evolution of RS Ophiuchi's 2021 nova explosion with the European VLBI network DTSTART;VALUE=DATE-TIME:20240904T094500Z DTEND;VALUE=DATE-TIME:20240904T100000Z DTSTAMP;VALUE=DATE-TIME:20260420T183853Z UID:indico-contribution-11-0-99@cern.ch DESCRIPTION:Speakers: Dr. LICO\, Rocco (INAF-IRA)\nNova outbursts are powe rful astronomical events occurring in binary star systems\, where a white dwarf accumulates material from its companion star until a critical pressu re and temperature are reached and trigger a thermonuclear outburst.\nIn t his talk we'll focus on the well known recurrent and symbiotic nova RS Oph iuchi (RS Oph) that experienced a new outburst in August 2021\, representi ng the first nova ever detected at very-high energies (E>100 GeV). In this context\, we present the results of a very long baseline interferometry ( VLBI) monitoring with the European VLBI Network (EVN) at 1.65 and 5 GHz\, performed from 14 to 65 days post-explosion. We characterized in great det ail the evolving morphology of the expanding bipolar ejecta and determined the physical conditions of the surrounding medium. We estimated the expan sion speed of the two elongated bipolar outflows\, the white dwarf accreti on rate\, the mass loss rate of the companion star\, the radial evolution of the surrounding medium density\, as well as the properties of the densi ty enhancement on the orbital plane.\n\nhttps://events.mpifr-bonn.mpg.de/i ndico/event/371/session/11/contribution/99 LOCATION:CJD Bonn Castell URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/99 END:VEVENT BEGIN:VEVENT SUMMARY:Numerical simulations and radiative signatures of transient and ep isodic jets DTSTART;VALUE=DATE-TIME:20240904T100000Z DTEND;VALUE=DATE-TIME:20240904T101500Z DTSTAMP;VALUE=DATE-TIME:20260420T183853Z UID:indico-contribution-11-0-108@cern.ch DESCRIPTION:Speakers: Dr. FROMM\, Christian (JMU Wuerzburg)\nObservations of transient and episodic jets allow us to study jet formation and particl e acceleration in real time. To better understand the possible physics beh ind these violent events we perform two-temperature 3D GRMHD simulations o f accreting black holes. Our simulations start with an initial torus in hy drostatic equilibrium seeded with a magnetic field with alternating polari ty. During the accretion process we trigger magnetic reconnection which le ads to three distinct flow states: (i) an intermittent flow that passes fr om quiescent states to a flaring state\, (ii) a quasi-steady-state with no jet\, and (iii) an accretion state similar to a magnetically arrested con figuration including a strong jet.\nIn addition\, our simulations lead to the formation of current sheets which provide ideal conditions for the acc eleration of non-thermal particles. \nFrom the GRMHD simulations we comput e the polarised radiative transfer including light curves\, broad-band spe ctra\, radio images a various frequencies and polarisation fractions. Fina lly our results can be compared to current and future observation of SgrA* or black hole binaries.\n\nhttps://events.mpifr-bonn.mpg.de/indico/event/ 371/session/11/contribution/108 LOCATION:CJD Bonn Castell URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/108 END:VEVENT BEGIN:VEVENT SUMMARY:Beyond the Core: Unveiling Multiple Gamma-Ray Production Zones in Blazar 3C 454.3 DTSTART;VALUE=DATE-TIME:20240904T101500Z DTEND;VALUE=DATE-TIME:20240904T103000Z DTSTAMP;VALUE=DATE-TIME:20260420T183853Z UID:indico-contribution-11-0-114@cern.ch DESCRIPTION:Speakers: Mrs. PALAFOX\, Eva (INAOE Puebla)\nWe present a mult i-wavelength analysis of the gamma-ray emission mechanisms within blazar 3 C 454.3. Using 12 years of gamma-ray data alongside multi-epoch VLBA obser vations at 15 and 43 GHz\, we explore the correlation between jet features and gamma-ray activity. Our analysis reveals a significant correlation be tween gamma-ray flux and core emission at 43 GHz and 15 GHz\, suggesting t hese core regions contribute substantially (37% and 30%\, respectively) to the overall gamma-ray\nproduction. Furthermore\, a quasi-stationary 43 GH z component at 4.6 pc and a mobile 43 GHz feature (0.8-2.3 pc\, βapp = 9. 9 ± 1.1 c) exhibit strong correlations with gamma-ray variations\, contri buting 18% and 26% to the high-energy emission\, respectively. The observe d co-variability across these extended jet regions strongly suggests Synch rotron Self-Compton (SSC) as the primary gamma-ray production mechanism. O ur discovery of a high-speed component (βapp = 9.9 ± 1.1 c) contributing to gamma-ray emission significantly challenges existing theoretical model s. Our findings highlight the potential presence of multiple\, and potenti ally non-stationary\, gamma-ray emitting regions within blazar jets\, furt hering our understanding of blazar complexity and SSC processes.\n\nhttps: //events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribution/114 LOCATION:CJD Bonn Castell URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/11/contribut ion/114 END:VEVENT END:VCALENDAR