Users October 2022

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12 participants
26 discussions

Eccentricity in BNS evolution with Lorene
by Bing-Jyun Tsao 06 Oct '22

06 Oct '22

Dear Einstein Toolkit community, I am Bing-Jyun (Johnny) Tsao, a graduate student at University of Texas at Austin. I am currently working on a project comparing our local version of BNS initial data (M. Clark, P. Laguna, 2016 Physical Review D 94 064058) with Lorene. When using Lorene, I found that the trajectory of the stars is showing eccentricity (as shown in the plot below), and this occurred when I ran Lorene with equal-mass BNS with ADM mass = 1.4 Msun, and with the publicly available Lorene data on their website "G2_I14vs14_D4R33_45km", both of which have an initial separation of 45 km. I use VolumeIntegral_GRMHD to track the stars, and GRHydro + ML_BSSN to evolve. Additionally, I also found that the ADM angular momentum from Lorene is about 20% smaller than that from our code which uses post-Newtonian calculations. My question is: >From my understanding, Lorene gives quasi-circular initial data. Thus, is it abnormal to see eccentricity, or is it a physical artifact, perhaps from tidal deformation, that always shows up when the stars are very close to each other? Here I attached my parfile and the trajectory for a run using the Lorene publicly available data "G2_I14vs14_D4R33_45km". Thanks in advance. Best, Johnny Tsao

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Meeting minutes for 2022-10-06
by Bing-Jyun Tsao 06 Oct '22

06 Oct '22

Present: Peter, Keith, Steven, Samuel, Roland, Beyhan, Johnny - ET release - Name was decided last time [RH] - testing has started: <http://einsteintoolkit.org/testsuite_results/index.php> http://einsteintoolkit.org/testsuite_results/index.php BNS example (Johnny), BBH (Yosef’s student), Beyhan can do TOV or Multipatch scalar but maybe for someone else who is new to ETK, will look for students [RH] - Mailing list questions - work station: writing an email [RH] - Issues - ticket #2653: performance issue, is currently fixed by commenting out the recursive loop, someone else should try to look and check [SC], will need a pull request [SB] - ticket #2639: th::regrid and CarpetLib has different time, send the parfile that shows the issue [SC] find where time is set for syncing the time levels, will need to check with Erik [RH] - ticket #2650: scalars have no interior so presync does not do anything [SC], partial fix is changing WRITE in presync [RH], complete fix is to modify the parsing method [SB] - ticket #2643: add macros to Meudon ID thorns [SC] - ticket #2642: error when running on deep bayou [PD] default option takes g++ compiler that might be too old, will need to set the g++ name gxx-name path-to-modern-g++ [RH] - major bug fix, will create a new ticket [LW] - set sourcebasedir in def.local.ini to current directory [SB] setup-silent as it is now should work, need to account for all users for people who use simfactory for other purposes than ETK [RH] - 2022-10-13 (-1mo): Feature freeze [RH] Next call: Chair: Steve Minutes: Roland

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European-funded postdoctoral and PhD positions in Theoretical Astrophysics, Frankfurt, Germany
by Prof. Dr. Luciano Rezzolla 06 Oct '22

06 Oct '22

Dear all, in case you have not come across it, there is a recent announcement for two European-funded postdoctoral and PhD positions in Theoretical Astrophysics, Frankfurt, Germany. People wishing more information can simply write to me. Best regards, Luciano --------------------------------------------------------------------------------- The group of Relativistic Theoretical Astrophysics in Frankfurt invites applications for one postdoctoral and one PhD position in Computational Theoretical Astrophysics. The positions are funded by the EuroHPC initiative dedicated to the creation of the multi-Institute Center of Excellence of HPC applications (SPACE). The work to be carried out will focus on the performance and scalability optimisation of numerical codes employed in relativistic-astrophysics simulations. Experience in HPC and GPU computing is required for the postdoctoral position and desirable for the PhD position. Candidates should have a PhD/MSc in astrophysics, physics or computer science for the postdoc/PhD position, respectively. The postdoctoral position is for four years while the PhD position is for three. The preferred starting date is 01.06.2023, but later appointments can be negotiated. The successful applicant(s) will be part of an international research group at the Institute for Theoretical Physics at Frankfurt, Germany. Interests of the group span from the modelling of the physics of neutron stars and black holes, to fundamental issues in gravitational physics (https://relastro.uni-frankfurt.de/). Frankfurt am Main is a lively and international city, and Europe’s financial center. The application should comprise a CV, a publication list, and a research summary. Applicants should also arrange for three letters of reference to be sent to the address below. Applications will have to be sent by 30.11.2022 for full consideration, but the search will remain open till the optimal candidates are found. Applications should be made electronically and sent to: Fr. Astrid Steidl: steidl[AT]itp.uni-frankfurt.de indicating in the subject whether you are applying for the PD or PhD position. Goethe University is an equal-opportunity employer and is committed to increasing the number of women in research and teaching. Qualified female researchers are therefore especially encouraged to apply. Applicants with severe disabilities and equal qualification and aptitude will be given preferential consideration. We prioritise diversity and are committed to creating an inclusive environment for everyone.

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Einstein Toolkit Meeting Reminder
by reminders＠einsteintoolkit.org 05 Oct '22

05 Oct '22

Hello, Please consider joining the weekly Einstein Toolkit phone call at 9:00 am US central time on Thursdays. For details on how to connect and what agenda items are to be discussed, use the link below. https://docs.einsteintoolkit.org/et-docs/Main_Page#Weekly_Users_Call --The Maintainers

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Agenda for Thursday's Meeting
by reminders＠einsteintoolkit.org 03 Oct '22

03 Oct '22

Please update the Wiki with agenda items for Thursday's meeting. Thanks! https://docs.einsteintoolkit.org/et-docs/meeting_agenda --The Maintainers

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Numerical relativity and computational astrophysics postdoctoral positions at RIT
by Carlos Lousto 03 Oct '22

03 Oct '22

Numerical relativity and computational astrophysics postdoctoral positions at RIT The RIT Center for Computational Relativity and Gravitation (CCRG) is currently seeking to fill one or two postdoctoral research positions, including a prestigious fellowship in multi-messenger astronomy, as part of several NASA and NSF collaborative projects. We are looking for highly qualified individuals interested in pursuing research in the fields of numerical relativity, theoretical and computational astrophysics, with an emphasis on general relativistic magneto-hydrodynamics simulations of compact object mergers, such as accreting binary, massive, black holes and binary neutron stars. Accreting supermassive binary black holes are promising multi-messenger sources because they strongly emit both gravitational wave and electromagnetic radiation. It is the goal of our group to combine astrophysical knowledge about the environments of these sources with detailed physical simulations of gas flows in the immediate neighborhoods of these binaries as they proceed from large orbital separations through the merger proper and postmerger, and to predict the signals observers would see to identify them. Similarly, we are interested on pushing the frontiers in developing new high-performance algorithms that will allow us to perform long-term simulations neutron star coalescences from prior to merger through to the formation of disks and/or collapse of the merged remnant, the production of jets, and launching of outflows. The group is actively developing new numerical codes and tools (e.g. AsterX, SphericalNR, Harm3D, PWMHD) as part of The Einstein Toolkit Consortium, and a large NASA Theoretical and Computational Astrophysics Network. The CCRG hosts a number of research scientists and students involved in gravitational wave data analysis from the LIGO Scientific Collaboration and the LISA consortium, and collaborate closely with the larger astrophysics group of observational astronomers gathering data from the Vera Rubin Observatory, Nanograv and JWST. Our researchers have access to several computing cluster facilities at national computing centers such as the TACC’s Frontera Supercomputer, XSEDE and a dedicated over 4000-cores cluster with 5 PB of storage pool hosted at the Center. Applications should consist of a cover letter, a brief statement of research interests, a curriculum vitae including publication list, and at least three letters of recommendation. All materials should be sent electronically as soon as possible to: mxcsma[AT]rit.edu <http://rit.edu/> with a copy to ccrg-postdoc[AT]ccrg.rit.edu <http://ccrg.rit.edu/>. More information about the CCRG is available at http://ccrg.rit.edu/ <http://ccrg.rit.edu/>. And about Rochester at http://en.wikipedia.org/wiki/Rochester,_New_York <http://en.wikipedia.org/wiki/Rochester,_New_York> Application material should also be uploaded here: https://sjobs.brassring.com/TGnewUI/Search/home/HomeWithPreLoad?partnerid=2… <https://sjobs.brassring.com/TGnewUI/Search/home/HomeWithPreLoad?partnerid=2…> Application reviews will be begin immediately and continue until the position is filled. Starting dates, duration and a competitive salary are negotiable. _______________________________________________

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Users October 2022