Archive for November, 2024

New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , on November 23, 2024 by telescoper

It’s Saturday morning so it’s time for the usual weekly update of publications at the Open Journal of Astrophysics. This week’s report will be short because there is only one paper to report this week, being  the 105th paper in Volume 7 (2024)  and the 220th  altogether. It was published on Wednesday 19th November 2024.

The title of the latest paper is”Early Bright Galaxies from Helium Enhancements in High-Redshift Star Clusters” and the authors are Harley Katz (U. Chicago), Alexander P. Ji (U. Chicago), Grace Telford (Princeton) & Peter Senchyna (Carnegie Observatories), all based in the USA. This paper, which is in the folder marked Astrophysics of Galaxies, discusses chemical abundance – specfically Helium enhancement – as a factor in the luminosity of high-redshift galaxies

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.

That’s all for this week – tune in next Saturday for next week’s update!

Galactic Outflows

Posted in Open Access, The Universe and Stuff with tags , , , on November 22, 2024 by telescoper

We have a visiting speaker for a colloquium this afternoon in the form of Dr Martin Rey, formerly of Oxford University and now a lecturer at the University of Bath. Last night at dinner I learned that he has a YouTube channel called Cosmic Rey (geddit?) so I thought I’d share one of the videos here.

The paper relating to this video can be found on the arXiv here.

P.S. Martin has now joined the Editorial Board of the Open Journal of Astrophysics.

Teaching Transforms

Posted in Education, History, Maynooth, The Universe and Stuff with tags , , , , , on November 21, 2024 by telescoper

We’re about two-thirds of the way into the Autumn Semester here at Maynooth and, by a miracle, I’m just about on schedule with both the modules I’m teaching. It’s always difficult to work out how long things are going to need for explanation when you’re teaching them for the first time.

One of the modules I’m doing is Differential Equations and Transform Methods for Engineering Students. I’ve been on the bit following the “and” for a couple of weeks already. The first transform method covered was the Laplace transform, which I remember doing as a physics undergraduate but have used only rarely. Now I’m doing Fourier Series, as a prelude to Fourier transforms.

As I have observed periodically, the differential equations and transform methods are not at all disconnected, but are linked via the heat equation, the solution of which led Joseph Fourier to devise his series in Mémoire sur la propagation de la chaleur dans les corps solides (1807), a truly remarkable work for its time that inspired so many subsequent developments.

In the module I’m teaching, the applications are rather different from when I taught Fourier series to Physics students. Engineering students at Maynooth primarily study electronic engineering and robotics, so there’s a much greater emphasis on using integral transforms for signal processing. The mathematics is the same, of course, but some of the terminology is different from that used by physicists.

Anyway I was looking for nice demonstrations of Fourier series to help my class get to grips with them when I remembered this little video recommended to me some time ago by esteemed Professor George Ellis. It’s a nice illustration of the principles of Fourier series, by which any periodic function can be decomposed into a series of sine and cosine functions.

This reminds me of a point I’ve made a few times in popular talks about astronomy. It’s a common view that Kepler’s laws of planetary motion according to which which the planets move in elliptical motion around the Sun, is a completely different formulation from the previous Ptolemaic system which involved epicycles and deferents and which is generally held to have been much more complicated.

The video demonstrates however that epicycles and deferents can be viewed as the elements used in the construction of a Fourier series. Since elliptical orbits are periodic, it is perfectly valid to present them in the form of a Fourier series. Therefore, in a sense, there’s nothing so very wrong with epicycles. I admit, however, that a closed-form expression for such an orbit is considerably more compact and elegant than a Fourier representation, and also encapsulates a deeper level of physical understanding. What makes for a good physical theory is, in my view, largely a matter of economy: if two theories have equal predictive power, the one that takes less chalk to write it on a blackboard is the better one!

Anyway, soon I’ll be moving onto the complex Fourier series and thence to Fourier transforms which is familiar territory, but I have to end the module with the Z-transform, which I have never studied and never used. That should be fun!

New Results from DESI

Posted in Barcelona, The Universe and Stuff with tags , , , , , , , on November 20, 2024 by telescoper
The Mayall Telescope at Kitt Peak, in which DESI is housed. This PR image was taken during a meteor shower, which is not ideal observing conditions. Picture Credit: KPNO/NOIRLab/NSF/AURA/R. Sparks

I’ve just got time between meetings to mention that a clutch of brand new papers has emerged from the DESI (Dark Energy Spectroscopic Instrument) Collaboration. There is a press release discussing the results from the Lawrence Berkeley Laboratory here and one from the ICCUB in Barcelona here; several members of the group I visited there during sabbatical are working on DESI. Congratulations to them.

I haven’t had time to read them yet, but a quick skim suggests that the results are consistent with the standard cosmological model.

The latest batch contains three Key Publications:

together with the companion supporting papers:

The links lead to the arXiv version of these papers. These articles can also be found, along with previously released publications by the DESI Collaboration, here.

Anyone who has read the latest papers is welcome to comment through the box below!

Weird Statistics

Posted in Biographical on November 19, 2024 by telescoper

I got one of these earlier today.

It hasn’t really been a ‘spike’ because it’s carried on all day. As of now (about 10pm local Irish  time), I’ve had over 7,000 hits today. That’s a lot more than average!

The weird thing is that the traffic isn’t all arriving at the same post, so I’ve no idea what triggered this surge. All I know is that most of the readers are based in the USA.

It’s a mystery!

Another interesting thing is that all those hits are coming from just a few hundred unique visitors. It could, therefore, be that all the extra traffic is from one site, in which case it might be someone scraping the content for AI purposes…

Update: the blitz lasted three days. Notice how the number of visitors did not go up, only the number of reads.

Maynooth University Library Cat Update

Posted in Maynooth with tags , , on November 18, 2024 by telescoper

It has been an unusually mild November until today, when it has suddenly turned colder and wetter. This alteration does not seem to have pleased Maynooth University Library Cat.

Picture Credit: Joost Slingerland

It’s LGBTQIA+ STEM Day!

Posted in LGBTQ+, Maynooth with tags , , , , on November 18, 2024 by telescoper

Just a quick post to point out that today is LGBTQIA+ STEM Day, which aims to celebrate  to celebrate the work of LGBTQIA+ people in science, technology, engineering, and maths (STEM), but also to highlight the barriers still facing us.

For more information see here.

This also provides an opportunity for me to send my best wishes to all LGBTQIA+ staff and students at Maynooth and around the world!

P.S. I’m reminded that it was 21 years ago today that Section 28 was finally repealed in England and Wales.

The Future of Diamond Open Access in Astrophysics

Posted in Biographical, Open Access with tags , , , , , , on November 17, 2024 by telescoper

The Open Journal of Astrophysics is now reasonably well established as a Diamond Open Access journal for the astrophysics community. We have published over a hundred articles so far this year at such a low cost that we can make our publications free to read and to publish. Thanks for all this is due to the volunteers on our Editorial Board, the excellent team at Maynooth University library, who have supported this project for 6 years, to the arXiv, as well of course to the authors who have chosen to publish with us.

Although we have established a good base, we’re still much smaller than the mainstream journals publishing just a few percent of their output. There is no sign of a slowdown at OJAp. Indeed there are signs that pace will pick up. I heard last week, for example, that Oxford University Press (the publisher of Monthly Notices of the Royal Astronomical Society) has decided to cancel the ‘Read-and-Publish’ agreement that allowed authors from Australian institutions to avoid APCs. I imagine we’ll get quite a few more submissions from Down Under thanks to that decision.

Nevertheless, we’ve a long way to go to catch up with the likes of A&A, MNRAS and ApJ in terms of numbers. If activity continues to grow then we will incur greater costs – our provider, Scholastica, charges us per paper. Those costs will still be smaller than regular journals, but I think it’s unfair that the expense of running a journal that serves the global astrophysics community should fall entirely on one small University in Ireland.

Expense is only one issue. I never envisaged that OJAp would be unique. It was more intended to be a proof of concept. I would like to see a range of Diamond Open Access journals offering a choice for authors and serving different sub-disciplines. Most universities nowadays have publishing operations so there could be network of federated journals, some based on arXiv and some based on other repositories. Perhaps institutions are worried about the expense but, as we have shown the actual cost, is far less than they are wasting on Article Processing Charges. I rather think it’s not the money that is the issue, just the unimaginatively risk-averse thinking in what passes these days for university management.

There are two simple – but not mutually exclusive – possibilities.

One is that astrophysics institutions club together and donate funds not only to keep OJAp going, but also to allow us to invest in improvements. A donation equivalent to the cost of just one APC for a typical journal would help us enormously. We do actually get some donations already, but more would always be welcome. In the long run, an investment in Diamond Open Access would pay back many times in savings; OJAp has already saved the worldwide community over £500,000.

The other is that other members of the community follow the lead of OJAp and set up their own journals. I wouldn’t see others as much as competitors, more as allies with community-led federated system. In the light of the OUP decision mentioned above, why don’t Australian research institutions set up their own version of OJAp? I’d be happy to discuss how to start up such a journal with anyone interested.

If you would like to discuss either of these possibilities please use the comment box below or email me here.

P.S. There is another issue concerning the future of OJAp, which is that I will be retiring in a few years, but now isn’t the time to discuss that one!

Social Media Better than Meta

Posted in Biographical with tags , , , , , , on November 16, 2024 by telescoper

You may or may not know that these blog posts appear automatically on various social media platforms.

I have been posting content automatically on Meta platforms, Facebook and Threads. Recently, however, Meta’s AI algorithm has been randomly blocking posts. A couple of weeks ago it blocked this post (about the Edgeworth family) on the grounds that it violated rules concerning “sexually explicit content”. Today it blocked this post (the weekly update for OJAp) on the grounds that it was identified as spam. I can see the need for an automatic screening given the huge volume of posts, but the problem is that my facebook feed is full of actual spam that gets through these filters while innocent posts get blocked. In other words the algorithm is crap. If you ask for a review of the decision, all Meta does is run the algorithm again – with the same results, which is a waste of time.

I haven’t got time to waste on such stupidity so I will shortly be deactivating automatic posts to Facebook and Threads; these generate very little traffic for me anyway.

There are, however, plenty of alternative ways of following this blog. You can subscribe by email or by RSS feed for a start. On other social media platforms I recommend the federated version on Mastodon here:

https://telescoper.blog/@telescoper.blog

They also appear on my personal Mastodon account here:

https://mastodon.social/@telescoper

Posts also appear on LinkedIn here:

https://www.linkedin.com/in/peter-coles-911912216/

and on my BlueSky account:

https://bsky.app/profile/telescoper.bsky.social

WordPress has just set up an automatic integration with BlueSky, on which I now have over 3000 followers, which is nice, but any one of these is better than Meta!

Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , on November 16, 2024 by telescoper

Once again it’s time for a Saturday morning update on activity at the  Open Journal of Astrophysics.  Since the last update we have published two more papers, taking  the count in Volume 7 (2024) up to 104 and the total published by OJAp up to 219.

The first paper of the most recent pair, published on November 13 2024,  in the folder Cosmology and NonGalactic Astrophysics, is “Stochastic Super-resolution of Cosmological Simulations with Denoising Diffusion Models” by Andreas Schanz, Florian List and Oliver Hahn (all based in the University of Vienna, Austria). It presents a  discussion of denoising diffusion in generative models for achieving super-resolution in simulations of cosmic large-scale structure.

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 this paper on the arXiv here.

The second paper to be published this week is also in the folder marked Cosmology and NonGalactic Astrophysics. It was published on November 14 and has the title “Halo mass functions at high redshift” by Hannah O’Brennan, John A. Regan, Chris Power (*), Saoirse Ward, John Brennan, and Joe McCaffrey. Five of the six authors are colleagues of mine from the National University of Ireland, Maynooth; Chris Power (marked with a *) is from the University of Western Australia.

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. More  next week!