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SUMMARY:Multi-wavelength-messenger study of Gamma Ray Bursts
DTSTART;VALUE=DATE-TIME:20240902T120000Z
DTEND;VALUE=DATE-TIME:20240902T124500Z
DTSTAMP;VALUE=DATE-TIME:20260307T083425Z
UID:indico-contribution-3-0-116@cern.ch
DESCRIPTION:Speakers: Dr. GHIRLANDA\, Giancarlo (INAF - Osservatorio Astro
 nomico di Brera)\nGamma Ray Bursts power highly collimated relativistic je
 ts which shine throughout the electromagnetic spectrum from the radio to t
 he TeV energy range. Short GRBs\, produced by the merger of compact binari
 es hosting at least a neutron star\, are key targets to exploit the multim
 essenger power of combining gravitational waves and electromagnetic observ
 ations. I will present the current knowledge of GRB jets with particular f
 ocus on what radio flux density monitoring and high resolution imaging can
  bring to the field and how the multi-messenger field may evolve towards t
 he third generation of gravitational wave interferometers.\n\nhttps://even
 ts.mpifr-bonn.mpg.de/indico/event/371/session/3/contribution/116
LOCATION:CJD Bonn Castell
URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/3/contributi
 on/116
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SUMMARY:Constraining the structure and the dynamics of Gamma-Ray Bursts wi
 th VLBI
DTSTART;VALUE=DATE-TIME:20240902T124500Z
DTEND;VALUE=DATE-TIME:20240902T130000Z
DTSTAMP;VALUE=DATE-TIME:20260307T083425Z
UID:indico-contribution-3-0-2@cern.ch
DESCRIPTION:Speakers: GIARRATANA\, Stefano (Osservatorio di Brera)\nThe ve
 ry long baseline interferometry (VLBI) technique offers unique insights in
 to the structure and dynamics of Gamma-Ray Bursts (GRBs). Specifically\, V
 LBI serves as a fundamental tool for measuring the apparent superluminal e
 xpansion (if the GRB is seen on-axis) and proper motion (if the GRB is obs
 erved slightly off-axis) of the GRB outflow\, enabling constraints on its 
 geometry and characterisation of the circum-burst medium. This complementa
 ry information already proved to be crucial in alleviating\, or even break
 ing\, the degeneracy in the modelling. In this talk\, I will focus on the 
 results from two recent bursts\, GRB201015A and GRB221009A. For the former
 \, interferometric observations played a critical role in characterising t
 he density profile of the circum-burst medium\, while VLBI observations of
  GRB221009A\, the brightest GRB ever recorded to date\, enabled us to meas
 ure the size and the expansion of the outflow. Lastly\, I will discuss fut
 ure prospects of radio interferometry in GRB research.\n\nhttps://events.m
 pifr-bonn.mpg.de/indico/event/371/session/3/contribution/2
LOCATION:CJD Bonn Castell
URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/3/contributi
 on/2
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SUMMARY:A Close-Up Look Into Explosive Transients
DTSTART;VALUE=DATE-TIME:20240902T130000Z
DTEND;VALUE=DATE-TIME:20240902T131500Z
DTSTAMP;VALUE=DATE-TIME:20260307T083425Z
UID:indico-contribution-3-0-5@cern.ch
DESCRIPTION:Speakers: Dr. GIROLETTI\, Marcello (INAF Istituto di Radioastr
 onomia)\nHigh-resolution imaging of explosive transient systems\, such as 
 supernovae and gamma-ray bursts\, enabled by VLBI offers a valuable and co
 mplementary perspective for studying these systems. By resolving the syste
 m down to milli-arcsec level\, VLBI studies of these transients shed impor
 tant insights into both intrinsic and extrinsic properties of the system. 
 Measurements of source size expansion\, proper motion\, and resolved morph
 ology can reveal important details about the geometry of the emitting regi
 on\, which in turn can help constrain the physical properties of the syste
 m such as the energetics\, magnetic field\, and ejecta/shock velocities. I
 n milli-lensed transient systems\, they can even provide a unique opportun
 ity to resolve the lensed images of the system\, an important element for 
 performing time-delay cosmography. In this poster\, I will show a few exam
 ples of gamma-ray bursts and supernovae which our team have conducted EVN 
 and VLBA observations for and demonstrate the important insights we have g
 ained from them. I will also demonstrate the important need for improved r
 eal-time correlation capabilities\, showing an example VLBI campaign where
  outcomes could be greatly improved with better real-time correlation capa
 bilities.\n\nhttps://events.mpifr-bonn.mpg.de/indico/event/371/session/3/c
 ontribution/5
LOCATION:CJD Bonn Castell
URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/3/contributi
 on/5
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SUMMARY:Unveiling the nature of thermonuclear runaway supernovae with radi
 o observations
DTSTART;VALUE=DATE-TIME:20240902T131500Z
DTEND;VALUE=DATE-TIME:20240902T133000Z
DTSTAMP;VALUE=DATE-TIME:20260307T083425Z
UID:indico-contribution-3-0-90@cern.ch
DESCRIPTION:Speakers: Dr. MOLDON\, Javier (IAA-CSIC)\nType Ia supernovae (
 SNe Ia) are thermonuclear explosions of degenerate white dwarf stars desta
 bilized by mass accretion from a companion star. Despite SNe Ia having bee
 n used to unveil the accelerated expansion of the universe\, the nature of
  their progenitors remains poorly understood. To distinguish between a deg
 enerate and non-degenerate progenitor companion\, one can use radio observ
 ations. A non-degenerate companion star is expected to lose material throu
 gh winds or binary interaction before the explosion\, and the supernova ej
 ecta colliding with this circumstellar material should produce radio synch
 rotron emission. However\, despite extensive efforts\, including some of t
 he deepest upper limits ever obtained by our team using e-MERLIN and the E
 VN\, no type Ia supernova has been detected at radio wavelengths. This sug
 gests a clean environment and a companion star that is itself a degenerate
  white dwarf.\n\nHere we present the results of our study of SN 2020eyj\, 
 showing the first-ever radio detection of a SN Ia. SN 2020eyj exhibits hel
 ium-rich circumstellar material\, as demonstrated by its spectral features
 \, infrared emission\, and a radio counterpart detected with e-MERLIN. Bas
 ed on our modeling\, we conclude that the circumstellar material probably 
 originates from a single-degenerate binary system in which a white dwarf a
 ccretes material from a helium donor star. We will briefly discuss this de
 tection in the context of the previous radio upper limits and their implic
 ations\, and describe in detail how we achieved this remarkable result. We
  will also discuss how a comprehensive radio follow-up of SN 2020eyj-like 
 SNe Ia can improve the constraints on their progenitor systems.\n\nhttps:/
 /events.mpifr-bonn.mpg.de/indico/event/371/session/3/contribution/90
LOCATION:CJD Bonn Castell
URL:https://events.mpifr-bonn.mpg.de/indico/event/371/session/3/contributi
 on/90
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