It’s Saturday morning so it’s time for the usual weekly update of publications at the Open Journal of Astrophysics. Once again this week’s report will be short because there is only one paper to report this week, being the 69th paper in Volume 7 (2024) and the 184th altogether. It was published on Wednesday 21st August 2024.
This week has been a bit strange, actually. We have actually accepted four papers that I was expecting to publish this week but only one has been published because the authors of the others have not yet put the final versions on arXiv. I suppose this is due to ongoing holidays and they’ll appear in due course. The other thing that happened was that when I published the paper below I discovered that the Crossref system was down for a scheduled upgrade that took a whole day to complete. Although I published the paper on 21st August I couldn’t register the metadata, etc, until 22nd August. Just as well I didn’t have more to do really!
Here is the overlay of the paper containing the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can also find the officially accepted version of the paper on the arXiv here.
It’s Saturday morning and time for the usual weekly update of publications at the Open Journal of Astrophysics. This will be a short post because there is only one paper to report this week, being the 68th paper in Volume 7 (2024) and the 183rd altogether. It was published on Thursday August 15th 2024.
Here is the overlay of the paper containing the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can also find the officially accepted version of the paper on the arXiv here.
It’s Saturday so it’s time once again for another roundup of business at the Open Journal of Astrophysics. After last week’s summer lull, this week I have three papers to announce, which brings the total we have published so far this year (Vol. 7) to 67 and the total published by OJAp to 182.
First one up, published on 7th August 2024, is “Brightest Cluster Galaxy Offsets in Cold Dark Matter” by Jonathan Katz of Washington University (St Louis, Missouri, USA), a simulation-based study of the distribution of the position of brightest cluster galaxies relative to the dark matter distribution and its possible use as a cosmological probe. The authors are Cian Roche (MIT), Michael McDonald (MIT), Josh Borrow (MIT), Mark Vogelsberger (MIT), Xuejian Shen (MIT), Volker Springel (MPA Garching), Lars Hernquist (Harvard), Ruediger Pakmor (Harvard), Sownak Bose (Durham, UK) and Rahul Kannan (York U., Canada). This paper is in the folder marked Astrophysics of Galaxies.
Here is a screen grab of the overlay, which includes the abstract:
The second paper to present is “LAMOST J1010+2358 is not a Pair-Instability Supernova Relic” by five authors based in the USA: Pierre Thibodeaux (Chicago), Alexander P. Ji (Chicago), William Cerny (Yale), Evan N. Kirby (Notre Dame) and Joshua D. Simon (Carnegie Observatories) . As the title makes clear, the paper presents arguments against previous claims that a particular star is not a pair-instability supernova relic. This paper is in the folder marked Solar and Stellar Astrophysics. It was published on Friday August 9th 2024.
The overlay looks like this:
You can read this paper directly on the arXiv here.
Last, but by no means least, comes “A Pilot Search for Gravitational Self-Lensing Binaries with the Zwicky Transient Facility“, results of a trial search for signals of gravitational lensing of one component in a binary system by a compact companion, with a discussion of future prospects for larger surveys. This one, which was also published on 9th August, is in the folder marked High-Energy Astrophysical Phenomena. The authors are Allison Crossland & Eric C Bellm (U. Washington), Courtney Klein (UC Irvine), James R. A. Davenport (U. Washington), Thomas Kupfer (Hamburg Observatory) and Steven L. Groom, Russ R. Laher & Reed Riddle (Caltech).
Here is a screengrab of the overlay:
To read the accepted version of this on the arXiv please go here.
That’s it for this week. I hope to post another update next weekend.
Looking at the title of this paper you might be tempted to dismiss it on the grounds that warp drives are the stuff of science fiction (which they are), but this paper is really a rigorous technical study of the dynamical evolution and stability of spacetimes that violate the null energy condition, inspired by the idea of a warp drive. As soon as I announced this paper on social media it started to get attention. That will probably increase because there is now a press release to accompany the paper. I’ve taken the liberty of reproducing the text of the press release here:
–o–
Imagine a spaceship driven not by engines, but by compressing the spacetime in front of it. That’s the realm of science fiction, right? Well, not entirely. Physicists have been exploring the theoretical possibility of “warp drives” for decades, and a new study published in the Open Journal of Astrophysics takes things a step further – simulating the gravitational waves such a drive might emit if it broke down.
Warp drives are staples of science fiction, and in principle could propel spaceships faster than the speed of light. Unfortunately, there are many problems with constructing them in practice, such as the requirement for an exotic type of matter with negative energy. Other issues with the warp drive metric include the potential to use it to create closed time-like curves that violate causality and, from a more practical perspective, the difficulties for those in the ship in actually controlling and deactivating the bubble.
This new research is the result of a collaboration between specialists in gravitational physics at Queen Mary University of London, the University of Potsdam, the Max Planck Institute (MPI) for Gravitational Physics in Potsdam and Cardiff University. Whilst it doesn’t claim to have cracked the warp drive code, it explores the theoretical consequences of a warp drive “containment failure” using numerical simulations.
Dr Katy Clough of Queen Mary University of London, the first author of the study explains: “Even though warp drives are purely theoretical, they have a well-defined description in Einstein’s theory of General Relativity, and so numerical simulations allow us to explore the impact they might have on spacetime in the form of gravitational waves.”
Co-author Dr Sebastian Khan, from Cardiff University’s School of Physics and Astronomy, adds: “Miguel Alcubierre created the first warp drive solution during his PhD at Cardiff University in 1994, and subsequently worked at the MPI in Potsdam. So it’s only natural that we carry on the tradition of warp drive research in the era of gravitational wave astronomy .”
The results are fascinating. The collapsing warp drive generates a distinct burst of gravitational waves, a ripple in spacetime that could be detectable by gravitational wave detectors that normally target black hole and neutron star mergers. Unlike the chirps from merging astrophysical objects, this signal would be a short, high-frequency burst, and so current detectors wouldn’t pick it up. However, future higher-frequency instruments might, and although no such instruments have yet been funded, the technology to build them exists. This raises the possibility of using these signals to search for evidence of warp drive technology, even if we can’t build it ourselves.
Dr Khan cautions “In our study, the initial shape of the spacetime is the warp bubble described by Alcubierre. While we were able to demonstrate that an observable signal could in principle be found by future detectors, given the speculative nature of the work this isn’t sufficient to drive instrument development.”
The study also delves into the energy dynamics of the collapsing warp drive. The process emits a wave of negative energy matter, followed by alternating positive and negative waves. This complex dance results in a net increase in the overall energy of the system, and in principle could provide another signature of the collapse if the outgoing waves interacted with normal matter.
This research pushes the boundaries of our understanding of exotic spacetimes and gravitational waves. Prof Dietrich comments: “For me, the most important aspect of the study is the novelty of accurately modelling the dynamics of negative energy spacetimes, and the possibility of extending the techniques to physical situations that can help us better understand the evolution and origin of our universe, or the avoidance of singularities at the centre of black holes.”
Dr Clough adds: “It’s a reminder that theoretical ideas can push us to explore the universe in new ways. Even though we are sceptical about the likelihood of seeing anything, I do think it is sufficiently interesting to be worth looking!”
The researchers plan to investigate how the signal changes with different warp drive models and explore the collapse of bubbles travelling at speeds exceeding the speed of light itself. Warp speed may be a long way off, but the quest to understand the universe’s secrets continues, one simulated crash at a time.
It’s Saturday morning, so once again it’s time for an update of activity at the Open Journal of Astrophysics. This week we have published another batch of four papers, the same number as last week, which takes the count in Volume 7 (2024) up to 64 and the total published altogether by OJAp up to 179.
Before announcing the week’s papers I’ll add three other updates you might find interesting:
When I looked at NASA/ADS this morning to help construct this post I saw that papers published in OJAp have now garnered over 2500 citations between them;
Last week we received a significant (unsolicited) cash donation from a higher education institution based in Europe to help with our work in Diamond Open Access. If any other organizations or individuals would like to do similar then please contact me!
Now, in chronological order, the four papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.
First one up is: “Widespread disruption of resonant chains during protoplanetary disk dispersal by Bradley M S Hansen (UCLA), Tze-Yeung Yu (UCLA) and Yasuhiro Hasegawa (JPL), all based in California, USA. The paper presents a discussion of the effect of a dispersing protoplanetary disk on the evolution of low-mass planets around a Solar mass star. It was published on 21st July 2024 and is in the folder marked Earth and Planetary Astrophysics.
Here is a screen grab of the overlay, which includes the abstract:
You can find the officially accepted version of the paper on the arXiv here.
The second paper to announce is “Using A One-Class SVM To Optimize Transit Detection” by Jakob Roche of the University of South Florida, also in the USA (but not in California). This articles discusses the advantages of One-Class Support Vector Machines (SVMs) over Convolutional Neural Networks (CNN) in the context of exoplanet detection. Its in the folder called Instrumentation and Methods for Astrophysics and was published on 25th July 2024.
You can see the overlay here:
The accepted version of this paper can be found on the arXiv here.
The next paper, also published on 25th July 2024, is in the folder marked High-Energy Astrophysical Phenomena. Its primary classification on arXiv is General Relativity and Quantum Cosmology (gr-qc), but it is cross-listed on astro-ph so we considered it for publication and had it refereed, with favourable results. It is entitled “What no one has seen before: gravitational waveforms from warp drive collapse” and is by Katy Clough (QMUL, UK), Tim Dietrich (Potsdam, Germany) and Sebastian Khan (Cardiff, UK). Looking at the title of this paper you might be tempted to dismiss it on the grounds that warp drives are the stuff of science fiction (which they are), but this paper is really a rigorous technical study of the dynamical evolution and stability of spacetimes that violate the null energy condition, inspired by the idea of a warp drive.
Here is the overlay:
You can find the full text for this one on the arXiv here.
Last, published on 26th July 2024, we have a paper with the title “A study of gamma-ray emission from OJ 287 using Fermi-LAT from 2015-2023” by Vibhavasu Pasumarti and Shantanu Desai of the Indian Institute of Technology, Hyderabad, India. It is an investigation of the properties of gamma-ray emission from OJ287 (a BL Lac object) using the Fermi Large Area Telescope (LAT). This one is also in the folder marked High-Energy Astrophysical Phenomena; here is the overlay
You can find the officially accepted version of this paper on the arXiv here.
That’s all for this week. Stay tuned for another update next week.
This week we have published four papers at the Open Journal of Astrophysics, which I now present to you here. These four take the count in Volume 7 (2024) up to 60 and the total published altogether by OJAp up to 175. It is gratifying to see the range of high-quality papers published steadily increasing. We are getting several papers submitted every day now.
In chronological order, the four papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.
First one up is: “A population of neutron star candidates in wide orbits from Gaia astrometry” by Kareem El-Badry (Caltech, USA) and 12 others based across the world. The paper presents a spectroscopic study of neutron star candidates identified using GAIA astrometry to be in wide binary orbits around main sequence stars, was published on 15th July 2024 and is in the folder marked Solar and Stellar Astrophysics. For more information about this one, see here.
Here is a screen grab of the overlay, which includes the abstract:
You can find the officially accepted version of the paper on the arXiv here.
The second paper to announce is “Systematic Effects in Galaxy-Galaxy Lensing with DESI” and was written by Johannes Ulf Lange (University of Michigan, Ann Arbor, USA) and 58 others, again distributed internationally. This one reports a study of systematic effects (such as incompleteness and intrinsic alignment) on galaxy-galaxy lensing results from the Dark Energy Spectroscopic Instrument (DESI) survey. This one is in the folder called Cosmology and NonGalactic Astrophysics and was published on 16th July 2024.
You can see the overlay here:
The accepted version of this paper can be found on the arXiv here.
The next paper is also in the folder called Cosmology and NonGalactic Astrophysics. It is entitled “Unleashing cosmic shear information with the tomographic weak lensing PDF” and is by by Lina Castiblanco (Newcastle Univresity, UK), Cora Uhlemann (Bielefeld University, Germany), Joachim Harnois-Déraps (Newcastle University, UK) and Alexandre Barthelemy (Ludwig-Maximilians-Universität, Germany). This one was published on 17th July 2024.
Here is the overlay:
You can find the full text for this one on the arXiv here.
Last but by no means least, published on 18th July 2024, we have a paper entitled “When to interfere with dark matter? The impact of wave dynamics on statistics“. The primary classification for this one is again Cosmology and Nongalactic Astrophysics and it discusses the imprint of wave-mechanical behaviour, perhaps associated with ultra-light scalar field dark matter on the statistical properties of large-scale structure. The authors are Alex Gough (Newcastle University, UK) and Cora Uhlemann (Bielefeld University, Germany; who also featured in the author list of the previous paper). This is a paper close to my own interests, but because I know both authors well and was the PhD examiner of the first author I thought it best to recuse myself from an editorial role on this one.
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
It did look likely at one stage that we might publish a paper every day last week, but the final version of one other paper didn’t make it onto arXiv in time to be announced on Friday so I will publish that one on Monday.
I saw an article in the Guardian yesterday with the title Academic journals are a lucrative scam – and we’re determined to change that. It’s written by Arash Abizadeh who is Professor of Political Science at McGill University in Canada. I urge you to read the piece if you’re interested in Open Access and the issues surrounding it.
I agree with virtually everything in the article. Indeed I’ve been saying much the same thing for about 15 years! I’m also determined to change things too, which is why we set up the Open Journal of Astrophysics, a “Diamond” Open Access Journal. Talking about the system of Gold Open Access, Prof. Abizadeh writes:
There is an obvious alternative: universities, libraries, and academic funding agencies can cut out the intermediary and directly fund journals themselves, at a far lower cost. This would remove commercial pressures from the editorial process, preserve editorial integrity and make research accessible to all. The term for this is “diamond” open access, which means the publishers charge neither authors, editors, nor readers (this is how our new journal will operate). Librarians have been urging this for years. So why haven’t academics already migrated to diamond journals?
I think the reason more academics haven’t already migrated to Diamond Open Access journals is that there are relatively few such journals. The reason for that is that although there are lots of people talking about Diamond Open Access there are many fewer actually taking steps to implement it. The initiative mentioned in the Guardian article is therefore very welcome. Although I think in the long run this transition is inevitable, it won’t happen by itself. It certainly won’t be helped by the Academic Publishing Industry either. We academics have to provide the push.
Here’s another excerpt:
Career advancement depends heavily on publishing in journals with established name recognition and prestige, and these journals are often owned by commercial publishers. Many academics – particularly early-career researchers trying to secure long-term employment in an extremely difficult job market – cannot afford to take a chance on new, untested journals on their own.
This is true, up to a point.
First of all any institution that has signed up to the San Francisco Declaration On Research Assessment (DORA) should not be relying on (often bogus) indicators of prestige such as the Journal Impact Factor or the journal’s presence in the Scopus index. If Diamond Open Access is to gain further traction it has to be accompanied to a wholesale change towards fairer research assessment practices.
Second, although it is true that it has taken some years to reach the volume it has now, I have been pleasantly surprised how many early career researchers in astrophysics have been keen to try out the Open Journal of Astrophysics. I think that’s because (a) early career researchers have not been indoctrinated into the absurdities of existing publishing practices and (b) they can see that the citation rates on OJAp are no worse than other allegedly more “prestigious” journals.
I usually only do updates at weekends about papers published in the Open Journal of Astrophysics but I’m making an exception today because a paper we published yesterday is making some waves that I think are worth propagating. The paper is called “A population of neutron star candidates in wide orbits from Gaia astrometry” and the first author is Kareem El-Badry of Caltech (USA); his institution have put out a press release to go with the paper which you an read for more details. They key point is that these are main sequence stars with (probably) neutron star companions and nobody really knows how such systems formed. The paper is also yet another illustration of the amazingly rich source of discovery data that is the European Space Agency’s Gaia mission.
The press release also contains some snazzy graphics, such as this:
The press release explains
The new study, which includes a team of co-authors from around the world, was published in The Open Journal for Astrophysics. Data from several ground-based telescopes, including the W. M. Keck Observatory on Maunakea, Hawai‘i; La Silla Observatory in Chile; and the Whipple Observatory in Arizona, were used to follow up the Gaia observations and learn more about the masses and orbits of the hidden neutron stars.
It is very gratifying to see one of our papers gaining such traction. It also exemplifies something that has struck me recently. Obviously, when we started the Open Journal of Astrophysics I really had no idea how it would go, but one thing that has surprised me (in a pleasant way) is how many articles we are getting from authors based in high-profile US institutions, such as Caltech, Harvard, Princeton and Berkeley (among others). I always assumed that such institutions were rich enough not to be worried by the cost of Article Processing Charges and, being based in America, the authors would in any case be used to paying page charges for the Astrophysical Journal which has been standard practice for ages. Whatever the reason, it sends a great message to the community to see these leading institutions going via the Diamond Open Access route. I hope this provides even more evidence to persuade even more authors that OJAp is a serious journal!
Another Saturday, another update of the Open Journal of Astrophysics. Since the last update we have published two more papers, taking the count in Volume 7 (2024) up to 56 and the total published by OJAp up to 171. Both these papers were published on Thursday 11th July 2024.
The first paper of the most recent pair, published on July 3rd 2024, is “Sunyaev-Zeldovich signatures from non-thermal, relativistic electrons using CMB maps” by Sandeep Kumar Acharya of The Open University of Israel, Ra’anana, Israel. This article presents a discussion the possible effects of non-thermal electron energy distributions on the form of Sunyaev-Zeldovich distortions and how they might be measured. The paper is in the folder marked Cosmology and NonGalactic Astrophysics.
Here is a screen grab of the overlay which includes the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
The second paper has the title “On the contribution of dwarf galaxies to reionization of the Universe” and is by Zewei Wu and Andrey Kravtsov of the University of Chicago in the USA. This paper, which is in the folder marked Astrophysics of Galaxies, presents a model of galaxy formation that suggests that radiation from very faint galaxies may contribute significantly to the reionization of the Universe.
Here is a screen grab of the overlay which includes the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
That concludes this week’s update. No doubt I’ll have more for you next week!
My own laptop is still with the menders but I’ve managed to borrow one until I get it back so I don’t get too far behind. Anyway, it’s Saturday morning, and once again time to post another update relating to the Open Journal of Astrophysics. Since the last update we have published two more papers, taking the count in Volume 7 (2024) up to 54 and the total published by OJAp up to 169. There was one less arXiv update than usual last week, owing to the holiday on July 4th, so a couple of papers have been delayed.
The first paper of the most recent pair, published on July 3rd 2024, is “Recovering 21cm Monopole Signals Without Smoothness” by Rugved Pund & Anže Slosar (Stony Brook, NY, USA) and Aaron Parsons (Berkeley, CA, USA) . This paper presents a new method for identifying the ‘Dark Ages’ trough contribution to the monopole of the 21cm radiation background that does not rely on the assumption that the spectrum is smooth. The paper is in the folder marked Cosmology and NonGalactic Astrophysics.
Here is a screen grab of the overlay which includes the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
The second paper, also published on 3rd July, has the title “LtU-ILI: An All-in-One Framework for Implicit Inference in Astrophysics and Cosmology”. There are fifteen authors with primary affiliations as follows: Matthew Ho (IAP, Paris, France), Deaglan J. Bartlett (IAP, Paris, France), Nicolas Chartier (Seoul National University, Korea), Carolina Cuesta-Lazaro (Cfa, Harvard, USA), Simon Ding (IAP, Paris, France), Axel Lapel (IAP, Paris, France), Pablo Lemos (Université de Montréal, Canada), Christopher C. Lovell (University of Portsmouth, UK), T. Lucas Makinen (Imperial College, London, UK), Chirag Modi (Flatiron Institute, NY, USA), Viraj Pandya (Columbia University, NY, USA), Shivam Pandey (Columbia University, NY, USA), Lucia A. Perez (Flatiron Institute, NY, USA), Benjamin Wandelt (IAP, Paris, France), and Greg L. Bryan (Sorbonne Université, Paris, France).
This paper, which is in the folder marked Instrumentation and Methods for Astrophysics, presents a suite of software for rapid, user-friendly, and cutting-edge inference using machine learning in astrophysics and cosmology. The software can be found on Github here.
Here is a screen grab of the overlay which includes the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
That concludes this week’s update. No doubt I’ll have more for you next week!
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In the Dark 