RagTime conference in Opava (virtual)

On October 19-23, we participated in the 22nd RAGTime workshop organized by our colleagues in Opava. This time, the meeting was virtual. It was also celebrating the 70th birthday of Professor Zdenek Stuchlik.

The CTP astrophysics group presented our results, on the modeling of relativistic jets (Bestin James), black hole spin-up in collapsars (Agnieszka Janiuk) and wind-fed accretion in Cygnus X-1 (Ishika Palit). The website of the conference is here under this link. All lectures have been recorded and are available on youtube channel under this link .

fig2a(1)


Posted in Uncategorized by with no comments yet.

Extraordinary Congress of Polish Physicists

On October 16-18 in Warsaw, we held XLVI Extraordinary Congress of Polish Physicists.

Because of pandemics, the event has been postponed from April 2020. Moreover, the form of this event was hybrid, and the lectures were presented in the Auditorium of the Warsaw University of technology, while majority of participants were joined remotely, and watched the lectures on the Youtube channel.

All events of the Congress are available under the links on the website: https://100lat.ptf.net.pl/?page=programme and https://100lat.ptf.net.pl/?page=posters. The Organizers encourage also to spend some time and learn the materials about education in physics: https://100lat.ptf.net.pl/?page=bazaar.

The astrophysicists from CTP PAS presented a poster about “Cosmic gamma ray bursts” (aut. Agnieszka Janiuk and Bestin James).

Fig_jet1


Posted in Uncategorized by with no comments yet.

Virtual Conference of POTOR

On September 24-26, we held the Virtual Conference of the Polish Society on Relativity 2020.
The young researchers from CFT, Ishika Palit and Michal Zajaczek, gave presentations of their current science projects results, during the 1st day  of the meeting.
CFT PAS actively participated in the organization of this conference, which aims to bring Polish and foreign relativists together to exchange ideas on a broad range of subjects related to General Relativity.
The conference is divided into six plenary sessions:
Mathematical and Numerical Relativity
Relativistic Astrophysics
Gravitational Waves
Cosmology
Quantum Gravity and Quantum Cosmology
Beyond General Relativity
We have more than 180 registered participants.
The program consist of 6 keynote lectures, 12 invited reviews, and 34 contributions, selected out of over 150 submitted abstracts.
VP_2

Posted in Uncategorized by with no comments yet.

Clumpy wind accretion in Cygnus X-1

Cygnus X-1 is one of the brightest X-ray sources observed and shows the X-ray intensity variations on time scales from milliseconds to months in both the soft and hard X-rays. In the recent work by Ishika Palit, Agnieszka Janiuk and Bożena Czerny, we aim to understand the physical mechanism responsible for the short timescale X-ray variability(<100 s) of the source in its Hard/Low state. The simulated GR Hydrodynamical model with shock solutions is in good agreement with the observed power density spectra of the source.
Article in print in ApJ is available on-line under this link.
Schematic

Posted in Uncategorized by with no comments yet.

Article about disappearing star accepted to ApJ Letters

Our article entitled “On the maximum stellar rotation to form a black hole without an accompanying luminous transient”, by Ariadna Murguia-Berthier, co-authored by Aldo Batta, Agnieszka Janiuk, Ilya Mandel, Enrico Ramirez-Ruiz and Rosa Wallace-Everson, has been accepted for publication in the Astrophysical Journal Letters.

In this work, we use the results of GR MHD simulations to constrain the maximal stellar rotation rates of the disappearing massive progenitors PHL293B-LBV and N6946-BH1, and to provide an estimate of the overall rate of disappearing massive stars. We find that about a few percent of single O-type stars with measured rotational velocities are expected to spin below the critical value before collapse and are thus predicted to vanish without a trace.

The ArXiv link to the text is here.


Posted in Uncategorized by with no comments yet.

Master thesis defended at Jagiellonian University

On July 23, 2020, Ms. Dominika Król defended her Master Thesis prepared at CTP PAS, under the supervision of prof. Agnieszka Janiuk. The thesis title was “Evolution of the spin of the black hole during the accretion. Analytical model and MHD simulations”. The defense exam was graded excellent and the thesis has been awarded honors by its referees.  The commitee members at Astronomical Observatory of Jagiellonian University were professors Stanisław Zoła and Sebastian Szybka. From October 2020, Ms Dominika Król will start the PhD program at Jagiellonian University.

A03S04Beta1Rhodump081


Posted in Uncategorized by with no comments yet.

TCAN workshop on Compact Binaries

On July 6-10, 2020, we attended the TCAN Workshop on Binary Neutron Stars Workshop, organized by prof. Manuela Campanelli (Rochester Institute of Technology). The meeting was fully virtual, but successfully brought together the specialists working on numerical relatitvity and compact binary mergers simulations. Agnieszka Janiuk from CTP PAS spoke about the Nucleosynthesis in post-merger outflows.

The website of the meeting is available here. All talks have been recorded and can be viewed on Youtube,

gravitational_waves


Posted in Uncategorized by with no comments yet.

Postdoctoral position in our group

We are currently inviting applications for the 3-year postdoctoral position in the CFT astrophysics group. The financing has been obtained through the NCN grant “Origin of Gamma Ray Bursts and their multimessenger appearance” under the supervision of prof. Agnieszka Janiuk. The link to official job announcement is here at CTP PAS website. The linked documents in pdf form have to be downloaded, and contain all information about application procedure. Application deadline is 31. July, 2020.


Posted in Uncategorized by with no comments yet.

NCN Opus grant awarded

Our team has won the Opus grant from National Science Center. The project entitled “Origin of gamma ray bursts and their multimessenger appearance” will be conducted by prof. Agnieszka Janiuk at Center for Theoretical Physics PAS for the years 2020-2024. The amount awarded for our research is 1 809 600 PLN.


Posted in Uncategorized by with no comments yet.

Seminar at CAMK

On April 8, Agnieszka Janiuk presented seminar talk in the virtual colloquium of Copernicus Astronomical Center. The title of the seminar was “Accretion onto black hole modeled via relativistic MHD simulations”.


Posted in Uncategorized by with no comments yet.