Archive for the OJAp Papers Category

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Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , on June 28, 2023 by telescoper

Time to catch up with a couple of recent publications at the Open Journal of Astrophysics.

The first paper was published on Friday 23rd June. It is the 21st in Volume 6 (2023) and the 86th in all.

The primary classification for this paper is Cosmology and Nongalactic Astrophysics and its title is “CosmoPower-JAX: high-dimensional Bayesian inference with differentiable cosmological emulators”. The paper is about a new method, based on machine learning, to construct emulators for cosmological power spectra for the purpose of speeding up inference procedures. The software described in the paper is available here.

The authors are Davide Piras (of the University of Geneva, Switzerland) and Alessio Spurio Mancini (of the Mullard Space Sciences Laboratory, University College, London, UK)

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 was published yesterday. It is the 22nd in Volume 6 (2023) and the 87th in all. Although 87 is an unlucky number for Australian cricketers – 13 short of a century – we’re still well on track to reach 100 papers by the end of the year.

Once again the primary classification for this paper is Cosmology and Nongalactic Astrophysics. The title of this one is “The alignment of galaxies at the Baryon Acoustic Oscillation scale” by Dennis van Dompseler, Christos Georgiou & Nora Elisa Chisari all of Utrecht University, in The Netherlands.

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.

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Copenhagen Looking Back

Posted in Biographical, Euclid, OJAp Papers, The Universe and Stuff on June 23, 2023 by telescoper

So here I am then, back in Maynooth. I had a relatively stress-free trip back, although my plane was a bit late and I had to run through Dublin Airport to catch the Hopper Bus I was booked on. Made it though.

The first thing I want to do is to thank the organizers for what was a wonderful event. I wasn’t able to attend the Euclid Consortium meeting in Oslo last year, largely because it was earlier in the year, in April (i.e. term-time) and I had teaching responsibilities. I gather it was a rather gloomy occasion because there was no concrete plan for the launch of Euclid thanks to the Russian war against Ukraine. I guess few would have predicted then that the 2023 meeting would be just a week or so before a launch on SpaceX!

I have to say the atmosphere was also helped by the excellent weather and very fine catering. The conference dinner was held in the Banqueting Hall, on the first floor of the Hans Christian Anderson Castle which stands at one of the entrances to the famous Tivoli Gardens, a few minutes from the conference venue.

Finally, one other memory that will stay with me for a while. It turned out that the week of the conference coincided with high-school graduation celebrations in Copenhagen, so every day we encountered lots of exuberant and largely inebriated teenagers around wearing funny hats and generally going a bit berserk. They made quite a lot of noise in the evenings, but it was all harmless. You’re only young once!

Having not been at an in-person conference for over four years, it was great to see some new faces and catch up with some people I haven’t seen for a long time. It was especially nice to talk to a couple of members of the Editorial Board of the Open Journal of Astrophysics. It was also nice to talk to some authors. Talking of which, here is Nicolas Tessore delivering a plenary presentation featuring work from one of the papers he has published with OJAp:

Anyway, I was up a stupid o’clock to catch my flight this morning so I think I’ll have a bit of rest and hope for the rain to stop so I can do some shopping.

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , on June 21, 2023 by telescoper

I may be away at a conference, but it’s still time to announce yet another new paper at the Open Journal of Astrophysics. This one was published on Monday 19th June.

The latest paper is the 20th  so far in Volume 6 (2023) and the 85th in all,  so with still more than half of 2023 remaining and many papers still in the pipeline, we’re on track to reach a total of 100 papers by the end of 2023!

The primary classification for this paper is Cosmology and Nongalactic Astrophysics and its title is “Sparse Bayesian mass-mapping using trans-dimensional MCMC”.  The paper describes a new trans-dimensional Markov Chain Monte Carlo sampler for mass-mapping, using wavelets, for the construction of mass maps from weak gravitational lensing which, as I’ve previously mentioned on this blog, is what the cool kids do these days.

The authors are: Augustin Marignier, Thomas D. Kitching & Jason D. McEwen (MSSL, Mullard Space Science Laboratory), Ana M. G. Ferreira (Department of Earth Sciences), all at University College London.

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.

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , on June 13, 2023 by telescoper

It’s time to announce yet another new paper at the Open Journal of Astrophysics. This one was published on Friday 9th June.

The latest paper is the 19th paper so far in Volume 6 (2023) and the 84th in all,  so with more than half of 2023 remaining and many papers still in the pipeline we’re on track to reach a total of 100 papers by the end of 2023!

The primary classification for this paper is Cosmology and Nongalactic Astrophysics and its title is “Categorizing models using Self-Organizing Maps: an application to modified gravity theories probed by cosmic shear”. For the uninitiated, a Self-Organizing Map is a machine-learning technique that makes large-dimensional data sets easier to analyze. This paper is yet another one about weak gravitational lensing (cosmic shear), which is obviously what the cool kids do these days.

The authors are: Agnès Ferté (JPL); Shoubaneh Hemmati (IPAC); Daniel Masters (IPAC); Brigitte Montminy (JPL); Peter L. Taylor (JPL); Eric Huff (JPL);  and Jason Rhodes (JPL).

(JPL=Jet Propulsion Laboratory, IPAC= Infrared Processing & Analysis Center, both associated with California Institute of Technology, Pasadena, USA)

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.

P.S. The first author tweeted about this paper:

 

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MOND: Open to Debate

Posted in OJAp Papers, The Universe and Stuff with tags , , on June 8, 2023 by telescoper

I didn’t know until today that there is a meeting going on this week at the University of St Andrews with the title 40 Years of MOND (Modified Newtonian Dynamics). Here’s a description of the conference.

The source of the gravitational field in objects ranging from individual galaxies to the largest scales in the universe is one of the biggest unanswered questions of modern physics. It is generally assumed that the gravitational field in extragalactic systems is dominated by dark matter particles occupying a dark sector that represents new physics beyond the stubbornly successful Standard Model of particle physics. So far, candidates for these particles have evaded detection in remarkably sensitive laboratory experiments: the evidence for missing mass remains entirely astrophysical in nature.

Forty years ago, Weizmann-Institute professor Mordehai Milgrom published a series of three articles in The Astrophysical Journal in which he proposed that the dark matter phenomenon is not due to unknown particles, but to a departure from the known laws of dynamics when the acceleration is about eleven orders of magnitude smaller than that on Earth’s surface (Milgrom 1983). Only one year later, in 1984, Jacob Bekenstein and Mordehai Milgrom developed this Modified Newtonian Dynamics (or Milgromian Dynamics, MOND) into a non-relativistic Lagrangian theory (Bekenstein & Milgrom 1984). During the ensuing decades, MOND has developed into a multifaceted paradigm that includes several non-relativistic and relativistic theory proposals, as well as possible connections with quantum gravity theories. Most remarkably, MOND has successfully made many striking and unique a priori predictions.

This conference will commemorate the last 40 years of this modern gravitational paradigm, of its predictive successes as well as its outstanding challenges, and will look to the road ahead.

It looks like an interesting meeting but what caught my eye in particular about it was this pic I found on Twitter today taken at the start of one of the talks:

The work presented apparently has been the focus of quite a lot of debate and several follow-up studies. I just thought I’d mention that it was published earlier this year in the Open Journal of Astrophysics:

It’s good to see work appearing in one of our publications attracting attention at an international conference!

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , , on May 26, 2023 by telescoper

It’s time to announce yet another new paper at the Open Journal of Astrophysics. This one was published yesterday (25th May).

The latest paper is the 18th paper so far in Volume 6 (2023) and the 83rd in all. With this one we have now published more papers in 2023 than we did in all of last year. With significantly less than half the year gone, and a large number of papers in the pipeline, I think it’s quite likely we will exceed a total of 100 papers by the end of 2023.

The primary classification for this paper is Cosmology and Nongalactic Astrophysics and its title is “The Effect of Splashback on Weak Lensing Mass Estimates of Galaxy Clusters and Groups”. For the uninitiated  “Splashback” of infalling material produces features in the radial density profile of galaxy clusters. This paper discusses the effect of this on cluster masses derived from weak lensing measurements.

The authors, most of whom have multiple affiliations, are: Yuanyuan Zhang (NOIRLab, Tucson, AZ, USA), Susmita Adhikari (IISER, Pune, India), Matteo Costanzi (Univ. Trieste, Italy) and Josh Frieman, Jim Annis & Chihway Chang (Univ. Chicago, IL, USA).

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, along with all other astrophysics and cosmology research papers worth reading, on the arXiv here.

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , on May 18, 2023 by telescoper

It’s time to announce yet another new paper at the Open Journal of Astrophysics. This one was published yesterday (17th May).

The latest paper is the 17th paper so far in Volume 6 (2023) and the 82nd in all. With this one we have now published as many papers so far in 2023 as we did in all of last year. With significantly less than half the year gone, and a large number of papers in the pipeline, I think it’s quite likely we will exceed a total of 100 papers by the end of 2023. How’s that for cosmic acceleration?

The primary classification for this paper is Instrumentation and Methods for Astrophysics and its title is “Deep-field Metacalibration”. This article describes a technique that reduces the pixel noise in estimators of weak gravitational lensing shear signals by using a deeper imaging survey for calibration.

The authors are Zhuoqi (“Jackie”) Zhang (University of Chicago, IL, USA), Erin Sheldon (Brookhaven National Laboratory, NY, USA), and Matthew Becker (Argonne National Laborary, IL, USA).

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, along with all other astrophysics and cosmology research papers worth reading, on the arXiv here.

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , on May 16, 2023 by telescoper

It’s time to announce yet another new paper at the Open Journal of Astrophysics. In fact it’s a little overdue, because we published this one on Friday 12th May, but I just got round to posting it on here.

The latest paper is the 16th paper so far in Volume 6 (2023) and the 81st in all. The primary classification for this paper is Instrumentation and Methods for Astrophysics and its title is “Metadetection Weak Lensing for the Vera C. Rubin Observatory“. I added the link to Wikipedia myself for those who might be unfamiliar with the Rubin Observatory.

The authors are Erin Sheldon (Brookhaven National Laboratory, NY, USA), Matthew Becker (Argonne National Laborary, IL, USA), Michael Jarvis (University of Pennsylvania, PA) and Robert Armstrong (Lawrence Livermore National Laboratory, CA) – all in the USA – and the LSST Dark Energy Science Collaboration, who have published a significant number of publications with OJAp. In fact, we’ll have another one in a day or two.

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, along with all other astrophysics and cosmology research papers worth reading, on the arXiv here

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff on May 1, 2023 by telescoper

It’s time for the announcement of yet another new paper at the Open Journal of Astrophysics. In fact it’s a little overdue, because we published this one on Friday 28th April but what with the impending holiday weekend, it slipped my mind to post it on here.

The latest paper is the 15th paper so far in Volume 6 (2023) and the 80th in all. This is another one for the folder marked Cosmology and Nongalactic Astrophysics and its title is “JAX-COSMO: An End-to-End Differentiable and GPU Accelerated Cosmology Library”. The software and related  documentation referred to in this paper can be found here.

The lead author of this paper is Jean-Eric Campagne of the Université Paris-Saclay in France, and there are nine co-authors based in France, Germany, USA, UK, China and Switzerland.

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.

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , on April 28, 2023 by telescoper

Time for the announcement of yet another new paper at the Open Journal of Astrophysics. The latest paper is the 14th paper so far in Volume 6 (2023) and the 79th in all. This one is in the folder marked Astrophysics of Galaxies and its title is “Massive Star Formation in Overdense Regions of the Early Universe”. The early Universe aspect does of course imply considerable overlap with cosmology.

The (sole) author is our very own John Regan of the Department of Theoretical Physics at Maynooth University.

Here is a screen grab of the overlay which includes the  abstract:

Here’s a bigger version of the image I chose for the overlay:

 

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.

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