In the Dark

Weekly Update from the Open Journal of Astrophysics – 17/01/2026

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags ALMA, arXiv:2502.07781v3, arXiv:2505.14787v3, arXiv:2507.07968v2, arXiv:2507.22888v4, arXiv:2509.00143v2, arXiv:2510.26901v2, arXiv:2601.05380v2, Astrophysics of Galaxies, Bayesian Methods, Cosmology and NonGalactic Astrophysics, Dark Energy Survey, dark matter, DES, Diamond Open Access, Diamond Open Access Publishing, galaxy formation, JWST, M31, Milky Way, Open Access, Open Access Publishing., Open Journal of Astrophysics, Oxygen, semi-analytic models, subhalos, The Open Journal of Astrophysics, Tomography, weak gravitational lensing on January 17, 2026 by telescoper

It’s Saturday once more so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published seven papers, bringing the number in Volume 9 (2026) to 11 and the total so far published by OJAp up to 459. This week has been quite busy; for only the second time in recorded history we published at least one paper each working day.

I will continue to include the announcements made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter which nobody should be using.

The first three papers this week were all published on Monday January 12th in the folder Astrophysics of Galaxies.

The first paper to report this week is “Rotational Kinematics in the Globular Cluster System of M31: Insights from Bayesian Inference” by Yuan (Cher) Li & Brendon J. Brewer (U. Auckland, New Zealand), Geraint F. Lewis (U. Sydney, Australia) and Dougal Mackey (independent researcher, Australia). This study uses Bayesian modelling to explore the kinematics of globular clusters in the Andromeda Galaxy, revealing distinct rotation patterns that suggest different subgroups were added at separate times.

The overlay is here:

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

The second paper is “DESI Data Release 1: Stellar Catalogue” by Sergey Koposov (U. Edinburgh, UK) and an international cast of 67 other authors. This paper introduces and describes the stellar Value-Added Catalogue (VAC) based on DESI Data Release 1, providing measurements for over 4 million stars, including radial velocity, abundance, and stellar parameters.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

Next we have “On the origins of oxygen: ALMA and JWST characterise the multi-phase, metal-enriched, star-bursting medium within a ‘normal’ z>11 galaxy” by Joris Witstok (Cosmic Dawn Centre, Copenhagen, Denmark) and 37 others in locations dotted around the world. This paper presents new ALMA observations of the JADES-GS-z11-0 galaxy confirm the presence of the [O III] 88 µm line, suggesting it consists of two low-mass components undergoing star formation and enriched in metals.

The overlay is here:

The official version can be found on arXiv here and the Fediverse announcement is here:

The fourth paper this week is also in the folder Astrophysics of Galaxies. but was published on Tuesday 13th January. It is entitled “Accelerated calibration of semi-analytic galaxy formation models” by Andrew Robertson and Andrew Benson (Carnegie Observatories, USA). This paper presents a faster calibration framework for galaxy formation models, using fewer simulations for each evaluation. However, the model shows discrepancies suggesting the model needs to be made more flexible.

The overlay is here:

You can find the officially accepted version on arXiv here and the Mastodon announcement here:

Next one up, published on Wednesday 14th January in the folder Cosmology and Nongalactic Astrophysics, is “Constraints from CMB lensing tomography with projected bispectra” by Lea Harscouet & David Alonso (U. Oxford), UK), Andrina Nicola (U. Manchester, UK) and Anže Slosar (Brookhaven National Laboratory, USA). This study presents angular power spectra and bispectra of DESI luminous red galaxies, finding that the galaxy bispectrum can constrain the amplitude of matter fluctuations and the non-relativistic matter fraction. The overlay is here:

You can find the officially accepted paper on arXiv here and the Mastodon announcement here:

The sixth paper this week is “Universal numerical convergence criteria for subhalo tidal evolution” by Barry T. Chiang & Frank C. van den Bosch (Yale U., USA) and Hsi-Yu Schive (National Taiwan University, Taiwan). This was published on Thursday 15th January in the folder Cosmology and Nongalactic Astrophysics; it presents an analysis of a simulation suite that addresses the ‘overmerging’ problem in cosmological simulations of dark matter subhalos, showing that up to 50% of halos in state-of-the art simulations are unresolved. The overlay is here:

The final accepted version of this paper can be found on arXiv here. The Mastodon announcement follows:

Finally for this week we have “Detectability of dark matter subhalo impacts in Milky Way stellar streams” by Junyang Lu , Tongyan Lin & Mukul Sholapurkar (UCSD, USA) and Ana Bonaca (Carnegie Observatories, USA). This was published on Friday 16th January (i.e. yesterday) in the folder Astrophysics of Galaxies. The study develops a method to estimate the minimum detectable dark matter subhalo mass in stellar streams, ranking them by sensitivity and identifying promising lines for further research.

The overlay is here:

The officially accepted version can be found on arXiv here and the Fediverse announcement here:

That concludes the update for this week. I will do another next Saturday.

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Marking Progress

Posted in Biographical, mathematics, Maynooth with tags Correcting, Differential Equations and Complex Analysis, Examinations, Marking on January 16, 2026 by telescoper

The last day of a week dominated by examination marking found me briefly back on campus to return the batch of scripts I have finished corrrecting and collect the next set (which, happily, is much smaller):

There are 14 scripts in the pile for my second paper, for my 4th year Mathematical Physics module on Differential Equations and Complex Analysis, around one-third of those for my Engineering Mathematics module Differentiaol Equations and Transform Methods. Based on the total number of examinations I have to mark I am therefore now 50% complete, but based on the number of scripts I’m about 75% through. I should be able to finish the latest batch in a day, but there’s no desperate rush so I’ll do them on Monday. I’m not going to start them now as I am off a concert – my first of 2026 – this evening and I prefer not to work at weekends unless I absolutely have to.

I finished the first set of marking yesterday, and spent most of this morning uploading and checking the scores and the conflation of exam marks with coursework scores. Satisfied that all is OK, I returned the scripts to the office for storage until our Examination Board meeting in about 10 days. I wasn’t on campus long, but there was a fire alarm in the Science Building while I was there. As usual, it turned out to be a false alarm.

Anyway, I should be finished with examination matters by Monday evening, which gives me four days next week to get on with other things. I’m looking forward to the change.

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The Exam Room – Cyril E. Power

Posted in Art with tags Art, Cyril E. Power, Examinations, Linocut, The Met on January 15, 2026 by telescoper

The Exam Room by Cyril E. Power (c. 1934, linocut, 26.6 x 38.2 cm, Metropolitan Museum of Art, New York; not on display)

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De-Dah – Elmo Hope Trio

Posted in Jazz with tags De-Dah, Elmo Hope, Elmo Hope Trio, Jazz, Paul Chambers, Philly Joe Jones on January 14, 2026 by telescoper

I’m in the middle of marking examinations so I will only do a brief post, while I take a short break, to follow up on the one about Hampton Hawes I did a couple of days ago. When I wrote that one it struck me that there are rather a lot of great musicians, especially pianists like Hampton Hawes, who were never appreciated as much as they should have been. Another that springs to mind is Elmo Hope, for whom Thelonious Monk seems to have been a great influence and who therefore provides an interesting contrast with Hampton Hawes who was perhaps more influenced by Bud Powell. Elmo Hope died young, largely because of a bad heroin habit, which also affected his career through his erratic behaviour and the criminal record he acquired for narcotics offences. He was a really fine musician and composer, though, with a very original voice and idiosyncratic sense of time. This track was recorded in 1953 with Paul Chambers on bass and Philly Joe Jones on drums, both of whom were to find fame with Miles Davis a few years later.

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Marking Time Once More

Posted in Biographical, Education, Maynooth with tags Correcting, Examinations, Marking, Maynooth University, Scripts on January 13, 2026 by telescoper

Lecturers at Maynooth University are supposed to be available on the telephone to deal with queries from students concerning their examinations. And so it came to pass that yesterday I was “on call”. Since I live in Maynooth, I decided to come into campus in case of a query so I could go to the examination venue l to deal with it if required. In the event, however, the examination passed off without incident and nobody called.

I wasn’t twiddling my thumbs all morning though. It seemed a good opportunity to go through the accumulated coursework for this module, applying various exemptions for medical or other reasons, so that when I’ve marked the scripts I can immediately combine the results with the CA component.

The examination venue, incidentally, was not on campus but in the Glenroyal Hotel in Maynooth. The Sports Hall on campus is usually one of the places for examinations to be sat, but it is not available this year due to refurbishment. The other day I was in one of the shops in the shopping centre next to the hotel and there were some complaints about the lack of available car parking spaces owing to so many students parking there for their exams. Anyway, the exam scripts found their way to my office this morning and here I am again, back home with a stack of an examination scripts to mark. The picture shows about 40 papers from my module on Differential Equations and Transform Methods. I want to get them out of the way as quickly as possible as I have another paper coming up on Thursday and have a lot of other things to do before term starts at the beginning of February. All the usual displacement activities having been exahusted, I’ve already made a start. With a bit of luck I’ll complete this task by Thursday.

I’ve often discussed the process of marking examinations with my colleagues and they all have different techniques. What I do is mark one question at a time rather than one script at a time. What I mean by that is that I go through every script marking all the attempts at Question 1, then I start again and do Question 2, etc. I find that this is much quicker and more efficient than marking all the questions in each script then moving onto the next script. The reason for this is that I can upload into my mind the model answer for Question 1 so that it stays there while I mark dozens of attempts at it so I don’t have to keep referring to the marking scheme. Other advantages are that it’s easier to be consistent in giving partial credit when you’re doing the same question over and over again, and that also you spot what the common mistakes are more easily.

Anyway, I’ve decided to take a break for today. I’ll start again tomorrow.

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The Unsolved Mysteries of Erich von Däniken

Posted in The Universe and Stuff with tags Chariots of the Gods, Charlatan, Erich von Däniken, Pseudoscience on January 12, 2026 by telescoper

News of the death of the notorious charlatan Erich von Däniken reminded me that at one time, when I was about 11 years old, I borrowed his book Chariots of the Gods from the public library. Even at that age I thought it was a load of nonsense, but I have to admit that I was fascinated by the origin of the Nazca Lines in Southern Peru, most of which were created between 500 BC and 500 AD but were probably based on even older structures. An example, depicting a humming bird, is shown here:

Von Däniken claimed that these were landing strips for ancient spacecraft piloted by extraterrestrials, an explanation that can easily be refuted. The actual purpose of these structures is yet to be discerned. I thought it was likely that they had some astronomical significance, but if they do then it has yet to be elucidated. How they were made is less difficult to explain: almost certainly they were made by scaling up smaller drawings. This would have required some mathematical understanding, and perhaps the use of coordinates, but there’s no reason to suppose that the people who created them lacked such knowledge. What they mean is indeed an unsolved mystery.

The other unsolved mystery is why people fall for the sort of nonsense peddled by von Däniken. It seems to me that part of the answer is that modern humans have an almost irresistible tendency to assume that earlier human beings were much less intelligent than us. This is clearly not true. In fact human intelligence has evolved very little over the past few millennia. What has evolved is knowledge (passed on cumulatively through the generations) and the technology created using that knowledge. Erich von Däniken promoted the idea that only extraterrestrials could have created the Nazca lines; he and others have suggested that the pyramids of ancient Egypt were built by aliens too. It’s part of our desire to think of ourselves as being much smarter than our ancestors. You only have to look at the world today to realize that humans aren’t as clever as they think they are. In fact we’re just as dumb as humans have always been; we just have better gadgets (including, unfortunately, weapons).

Another book I got out of the public library at about the same time was Worlds in Collision by Immanuel Velikovsky. As far as I can remember, this book propounded a new theory of the solar system in which the planet Venus was ejected from Jupiter and then went rattling around encountering other planets and causing various catastrophes. This was supposed to have happened around 1500 BC which “explains” various historical events, including many described in the Bible. It is nonsense of course, but some people lapped it up, as some continue to believe that the Earth is flat.

I find it hard to understand why some people persist in denying scientific advances for which there is considerable empirical evidence and prefer instead to believe in nonsense peddled by the likes of Erich von Däniken. If anyone can solve that mystery they will be doing the human race a very big favour.

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Carioca – Hampton Hawes Trio

Posted in Film, Jazz with tags Carioca, Charlie Parker, Flying Down to Rio, Hampton Hawes on January 11, 2026 by telescoper

The tune Carioca was a big hit in 1933 as a result of the film Flying Down to Rio (which, incidentally, saw the first pairing on screen of Fred Astaire and Ginger Rogers). There is a dance that goes with the tune, which involves the two dancers pressing their foreheads together, which always seem to me to risk an accidental headbutt (or present an opportunity for non-accidental one). Incidentally, “Carioca” is a slang term for a native of Rio de Janeiro.

Anyway, the popularity of the tune meant that many swing bands did versions: Benny Goodman, Artie Shaw and Woody Herman all had a go at it; the Artie Shaw version being particularly good. Later on, after the end of World War 2 and the arrival of the bebop era, many jazz musicians began to incorporate Latin-American rhythms and melodies into their work and this tune survived in various forms. There’s a very nice version by Chet Baker and Gerry Mulligan, for example.

My favourite is this marvellous up-tempo rendition by the shamefully underrated pianist Hampton Hawes and his trio recorded in 1955 with Red Mitchell on bass and Chuck Thompson on drums.

The pre-eminent modern piano stylists of the early fifties were Thelonious Monk and Bud Powell; Hawes was closer to the latter in approach, but it always seemed to me that he was the pianist paid the most direct musical homage to the great Charlie Parker; his solo on this is full of bebop licks and is taken at such a breakneck pace that even the nimble tread of the feet of Fred Astaire wouldn’t have been able to keep up.

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Weekly Update from the Open Journal of Astrophysics – 10/01/2026

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags arXiv:2504.05473v2, arXiv:2506.16434v3, arXiv:2506.22367v3, Astrophysics of Galaxies, Cosmology and NonGalactic Astrophysics, Dark Energy Survey, DES, Diamond Open Access, Diamond Open Access Publishing, Earth and Planetary Astrophysics, galaxy clustering, galaxy halo, Open Access, Open Access Publishing, Open Journal of Astrophysics, Planet 9, Power spectrum, Stellar Mass, The Open Journal of Astrophysics, weak gravitational lensing on January 10, 2026 by telescoper

Welcome to the first proper update for 2026 from the Open Journal of Astrophysics. The New Year brings us to Volume 9. In many countries, especially in Europe, Christmas is celebrated on January 6th so this week was also affected by the holiday season. Nevertheless, since the last update we have published four papers, bringing the number in Volume 9 (2026) to 4 and the total so far published by OJAp up to 452.

The first paper this week (and of course the first of 2026) is “A targeted, parallax-based search for Planet Nine” by Hector Socas-Navarro and Ignacio Trujillo (both of the Instituto de Astrofísica de Canaria, Spain). This article describes a targeted search for the hypothesized Planet Nine in the outer solar system, using parallax position shifts. No credible candidates were found within the observed field. It was published on Tuesday January 6th in the folder Earth and Planetary Astrophysics. The overlay is here:

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

The second paper is “Going beyond S₈: fast inference of the matter power spectrum from weak-lensing surveys” by Cyrille Doux (Université Grenoble Alpes, France) and Tanvi Karwal (U. Chicago, USA). This was published on Wednesday January 7th in the folder Cosmology and Nongalactic Astrophysics and it presents a new framework to extract the scale-dependent matter power spectrum from cosmic shear and CMB lensing measurements, revealing a consistent suppression in the matter power spectrum in galaxy-lensing. The overlay is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

Next we have “Constraining the Stellar-to-Halo Mass Relation with Galaxy Clustering and Weak Lensing from DES Year 3 Data” which is led by G. Zacharegkas et al. (Argonne National Laboratory, USA) and has 102 other authors too numerous to list by name from many institutions around the world again too numerous to list by name. It presents a framework to analyze the relationship between a galaxy’s stellar mass and its dark matter halo mass, using data from the Dark Energy Survey. The findings align with previous results. This paper was published on Thursday January 8th in the folder Astrophysics of Galaxies. The overlay is here:

The official version can be found on arXiv here and the Fediverse announcement is here:

Finally for this week we have “Distance measurements from the internal dynamics of globular clusters: Application to the Sombrero galaxy (M 104)” by Katja Fahrion (University of Vienna, Austria) and 9 others based in Spain, Australia, UK, USA, Brazil, Germany and Switzerland. This was published on Friday 9th January (yesterday) in the folder Astrophysics of Galaxies. This study uses the globular cluster velocity dispersion method to measure the distance to the Sombrero galaxy, finding it to be approximately 9.0 Mpc away. The overlay is here:

The officially accepted version can be found on arXiv here and the Fediverse announcement here:

That concludes the update for this week. I will do another next Saturday.

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Greenland’s Icy Mountains – William Topaz McGonagall

Posted in Poetry with tags Greeland's Icy Mountains, Poem, Poetry, William Topaz McGonagall on January 9, 2026 by telescoper

Photo by Jean-Christophe Andru00e9 on Pexels.com

Greenland's icy mountains are fascinating and grand,
And wondrously created by the Almighty's command;
And the works of the Almighty there's few can understand:
Who knows but it might be a part of Fairyland? 

Because there are churches of ice, and houses glittering like glass,
And for scenic grandeur there's nothing can it surpass,
Besides there's monuments and spires, also ruins,
Which serve for a safe retreat from the wild bruins. 

And there's icy crags and precipices, also beautiful waterfalls,
And as the stranger gazes thereon, his heart it appals
With a mixture of wonder, fear, and delight,
Till at last he exclaims, Oh! what a wonderful sight! 

The icy mountains they're higher than a brig's topmast,
And the stranger in amazement stands aghast
As he beholds the water flowing off the melted ice
Adown the mountain sides, that he cries out, Oh! how nice! 

Such sights as these are truly magnificent to be seen,
Only that the mountain tops are white instead of green,
And rents and caverns in them, the same as on a rugged mountain side,
And suitable places, in my opinion, for mermaids to reside. 

Sometimes these icy mountains suddenly topple o'er
With a wild and rumbling hollow-starting roar;
And new peaks and cliffs rise up out of the sea,
While great cataracts of uplifted brine pour down furiously. 

And those that can witness such an awful sight
Can only gaze thereon in solemn silence and delight,
And the most Godfearless man that hath this region trod
Would be forced to recognise the power and majesty of God. 

Oh! how awful and grand it must be on a sunshiny day
To see one of these icy mountains in pieces give way!
While, crack after crack, it falls with a mighty crash
Flat upon the sea with a fearful splash. 

And in the breaking up of these mountains they roar like thunder,
Which causes the stranger no doubt to wonder;
Also the Esquimaux of Greenland betimes will stand
And gaze on the wondrous work of the Almighty so grand. 

When these icy mountains are falling, the report is like big guns,
And the glittering brilliancy of them causes mock-suns,
And around them there's connected a beautiful ring of light,
And as the stranger looks thereon, it fills his heart with delight. 

Oh! think on the danger of seafaring men
If any of these mighty mountains where falling on them;
Alas! they would be killed ere the hand of man could them save
And, poor creatures, very likely find a watery grave! 

'Tis most beautiful to see and hear the whales whistling and blowing,
And the sailors in their small boats quickly after them rowing,
While the whales keep lashing the water all their might
With their mighty tails, left and right. 

In winter there's no sunlight there night or day,
Which, no doubt, will cause the time to pass tediously away,
And cause the Esquimaux to long for the light of day,
So as they will get basking themselves in the sun's bright array. 

In summer there is perpetual sunlight,
Which fill the Esquimaux's hearts with delight;
And is seen every day and night in the blue sky,
Which makes the scenery appear most beautiful to the eye. 

During summer and winter there the land is covered with snow,
Which sometimes must fill the Esquimaux' hearts with woe
As they traverse fields of ice, ten or fifteen feet thick,
And with cold, no doubt, their hearts will be touched to the quick. 

And let those that read or hear this feel thankful to God
That the icy fields of Greenland they have never trod;
Especially while seated around the fireside on a cold winter night,
Let them think of the cold and hardships Greenland sailors have to fight.

by William Topaz McGonagall (1825-1902)

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Exam Time Yet Again

Posted in Education, Maynooth with tags Examinations, Higher Education, Maynooth University, theoretical physics on January 8, 2026 by telescoper

The January examination period at Maynooth starts tomorrow (Friday 9th January), so I thought I’d do a quick post on the topic of examinations. First of all let me wish the very best of luck to everyone at Maynooth or elsewhere taking examinations in the next few weeks. I hope at least that the exam halls are nice and warm! Actually, owing to the Sport Hall being unavailable for this examination period owing to building work, some exams will be off campus; my first exam paper is actually being sat in the GlenRoyal hotel.

Here’s a video produced by Maynooth University to remind those taking exams of some general points about preparation and, most importantly, to look after themselves before during the examination period. It’s directed at Maynooth students but students from elsewhere may find useful tips in it.

I completed the last of my revision sessions today but, as the first examination for which I have responsibility is not until Monday 12th, I’ll have to wait to find out how any of my own students have done but let me take this opportunity to pass on a few of my own tips more aimed at students in Physics:

Try to get a good night’s sleep before the examination and arrive in plenty of time before the start. This is especially important when there’s bad weather that may disrupt travel. It is your responsibility to get to the examination on time!
Read the entire paper before starting to answer any questions. In particular, make sure you are aware of any supplementary information, formulae, etc, given in the rubric or at the end.
Start off by tackling the question you are most confident about answering, even if it’s not Question 1. This will help settle any nerves.
Don’t rush! Students often lose marks by making careless errors. Check all your numerical results on your calculator at least twice and – PLEASE – remember to put the units!
Don’t panic! You’re not expected to answer everything perfectly. A first-class mark is anything over 70%, so don’t worry if there are bits you can’t do. If you get stuck on a part of a question, don’t waste too much time on it (especially if it’s just a few marks). Just leave it and move on. You can always come back to it later.

Readers of this blog are welcome to add other tips through the comments box below!

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In the Dark

Weekly Update from the Open Journal of Astrophysics – 17/01/2026

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Marking Progress

The Exam Room – Cyril E. Power

De-Dah – Elmo Hope Trio

Marking Time Once More

The Unsolved Mysteries of Erich von Däniken

Carioca – Hampton Hawes Trio

Weekly Update from the Open Journal of Astrophysics – 10/01/2026

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Open Journal of Astrophysics

Greenland’s Icy Mountains – William Topaz McGonagall

Exam Time Yet Again

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