The Vernal Equinox 2024

Posted in Barcelona, The Universe and Stuff with tags , , on March 20, 2024 by telescoper

Loughcrew (County Meath, Ireland), near Newgrange, an ancient burial site and  traditional place to observe the sunrise at the Equinox

Just a quick note to mention that the Vernal Equinox, or Spring Equinox, (in the Northern hemisphere) took place today, Wednesday 20th March 2024, at 3.06 UTC (which was 4.06am CET, where I am at, though I was sound asleep at the time). Many people in the Northern hemisphere regard the Vernal Equinox as the first day of spring; of course in the Southern hemisphere, this is the Autumnal Equinox.

The date of the Vernal Equinox is often given as 21st March, but in fact it has only been on 21st March twice this century so far (2003 and 2007); it was on 20th March in 2008, has been on 20th March every spring from then until now, and will be until 2044 (when it will be on March 19th). This year the equinox happened before dawn, so sunrise this morning could be taken to be the first sunrise of spring. It felt more like summer, sipping coffee on my terrace in Barcelona:

This reminds me of a strange conversation I had on a plane recently. I was chatting to the person sitting next to me, who happened to be British. When he asked what I did for a living, I replied that I was an astrophysicist. He then complained that he preferred the old days when the Spring Equinox was on March 21st, and that now that Britain was out of the European Union he hoped it would change back…

Anyway, people sometimes ask me how one can define the `equinox’ so precisely when surely it just refers to a day on which day and night are of equal length, implying that it’s a day not a specific time?

The answer is that the equinox is defined by a specific event, the event in question being when the plane defined by Earth’s equator passes through the centre of the Sun’s disk (or, if you prefer, when the centre of the Sun passes through the plane defined by Earth’s equator). Day and night are not necessarily exactly equal on the equinox, but they’re the closest they get. From now until the Autumnal Equinox, days in the Northern hemisphere will be longer than nights, and they’ll get longer until the Summer Solstice before beginning to shorten again.

Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , , , , , , , , , , , , , on March 19, 2024 by telescoper

Now that I’m safely back in Barcelona it’s a time for a roundup of the latest business at the  Open Journal of Astrophysics. The latest batch of publications consists of three papers, taking the count in Volume 7 (2024) up to 20 and the total published by OJAp up to 135.

This time the papers are all related, have many authors in common, and have the same first author, Philip F. Hopkins of Caltech. In fact the second and third papers in this batch were accepted well before the first one, but it seemed to make much more sense to publish them together so I held those two back a bit and published all three on 14th March.

The three papers published, 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. You can read these publications directly on arXiv if you wish; you will find them here, here and here.

First one up is “FORGE’d in FIRE: Resolving the End of Star Formation and Structure of AGN Accretion Disks from Cosmological Initial Conditions” in which, using a full cosmological simulation, incorporating radiation and magnetohydrodynamics, the authors study the formation and structure of AGN accretion disks and their impact on star formation. This one is in the folder marked Astrophysics of Galaxies.

The authors (ten from the USA and one from Canada) are Philip F. Hopkins (Caltech), Michael Y. Grudic (Carnegie Observatories), Kung-Yi Su (Harvard), Sarah Wellons (Wesleyan University), Daniel Angles-Alcazar (University of Connecticut & Flatiron Institute), Ulrich P. Steinwandel (Flatiron Institute), David Guszejnov (University of Texas at Austin), Norman Murray (CITA, Toronto, Canada), Claude-Andre Faucher-Giguere (Northwestern University), Eliot Quataert (Princeton), and Dusan Keres (University of California, San Diego or UCSD for short).

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

 

 

The second paper to announce is “FORGE’d in FIRE II: The Formation of Magnetically-Dominated Quasar Accretion Disks from Cosmological Initial Conditions” which is a study of the formation and properties of highly magnetized accretion disks using numerical simulations that include the effects of radiation, magnetic fields, thermochemistry, and star formation.

This one is in the folder High-Energy Astrophysical Phenomena. The authors (ten based in the USA, one fin Canada, and one in New Zealand) are Philip F. Hopkins, Jonathan Squire (University of Dunedin, New Zealand), Kung-Yi Su (Harvard), Ulrich P. Steinwandel (Flatiron Institute), Kyle Kremer (Caltech), Yanlong Shi (Caltech), Michael Y. Grudic (Carnegie Observatories), Sarah Wellons (Wesleyan University), Claude-Andre Faucher-Giguere (Northwestern University), Daniel Angles-Alcazar (University of Connecticut & Flatiron Institute), Norman Murray (CITA, Toronto), and Eliot Quataert (Princeton).

 

The last paper of this batch, also in the folder High-Energy Astrophysical Phenomena, is  entitled “An Analytic Model For Magnetically-Dominated Accretion Disks” and is closely related to the previous one; this particular paper presents an analytic similarity model for accretion disks that agrees remarkably well with the simulations in the previous one. Animations of the simulations referred to in both papers can be found here.

Here is the overlay:

The authors of this one are Philip F. Hopkins, Jonathan Squire, Eliot Quataert, Norman Murray, Kung-Yi Su, Ulrich P. Steinwandel, Kyle Kremer, Claude-Andre Faucher-Giguere, and Sarah Wellons. You can find all their affiliations above.
That’s all for now. More news in a week or so!

 

 

Not in Not-Barcelona

Posted in Barcelona, Biographical with tags , on March 18, 2024 by telescoper

So here I am, after far too long an absence, back in Barcelona. I had to get up at silly o’clock (i.e. 3am) to get the bus to Dublin Airport to get a flight this morning. If that weren’t bad enough, the airport was littered with people clearly the worse for wear after Paddy’s Day yesterday. Today is a public holiday in Ireland, but some folks decided to travel rather than recuperate.

There was some drama on the flight too. About halfway through, the cabin crew asked if there was a doctor or a paramedic on board. I feared that someone had been taken seriously ill, but it seems it was just someone suffering the aftermath of yesterday’s indulgence. I didn’t see what happened as it was at the rear of the aircraft, and I was in row 10.

After that we were delayed landing by about 20 minutes as there was fog at Barcelona Airport that had slowed operations down; we circled for a while waiting for the mist and the backlog to clear. When we did land the fog was barely perceptible. The rest of the day has been very nice – a mild 19 degrees and sunny.

I made my way by bus from the Airport and thence on foot to the apartment in which I’ll be spending most of the time until the summer. It’s very nice, in a central location on Rambla de Catalunya. I’m on the top (6th) floor, with a nice terrace overlooking the street. I’m only 2 minutes from the Metro station at Passeig de Gràcia and Gaudi’s Casa Batlló; there was a crowd outside this afternoon as there has been every time I passed this place!

Anyway, I found my way back to the same office I was in last semester, where I await yet another Zoom call*. After that I’ll get a few essentials for the flat and have an early night. I’m looking forward to not travelling for the next several weeks.

*More excitement – the fire alarm went off, so we had to evacuate the building, but it seems to have been a false alarm.

Six Nations Summary

Posted in Rugby with tags , , , , , , , , , on March 17, 2024 by telescoper

I didn’t see many of the games in this year’s Six Nations Rugby because I was abroad for most of it, but yesterday I saw the last round of matches. The last one, between France and England in Lyon, was probably the best game I’ve seen in this year’s tournament. After a fascinating ebb and flow, England thought they had snatched it with a converted try to make it 31-30 with just a couple of minutes to go, but then immediately conceded a penalty on the halfway line. Up stepped Thomas Ramos, who had scored from a similar distance earlier in the game, stepped up and scored. France won 33-31 in a game that could have gone either way. It was effectively a playoff for 2nd place.

Earlier in the day, Ireland held off a spirited challenge from Scotland in a tense and scrappy match to win 17-13 which guaranteed they would be Six Nations Champions. for the sixth time. I don’t think the team reached the heights of last year’s Grand Slam but it was a deserved victory. It was all a bit more comfortable than the scoreline suggests, though Scotland did score a try late on when Ireland lost concentration which made for a nervy few minutes. A defeat would have meant metaphorical rain on the St Patrick’s Day parades going on today, but in the end there was no rain, either metaphorical or literal.

Given the result in Lyon, Ireland would have been Champions by virtue of their bonus points, even if they had lost to Scotland. England (who beat Ireland last week in a game I didn’t see) had to win with a bonus point to catch them; they managed the bonus point for four tries, but lost the match. Some pundits have commented on whether it was fair for a team to have won having lost more games than the second place team. Of course all the teams know the rules before the competition starts, so there’s no point complaining after the fact. Ireland played attacking rugby knowing that the try count might be important. However, I do think there is a point. In the old Five Nations, and indeed in the World Cup Pools, each team played four games. A bonus point from each of those matches would add 4 to a team’s total, the same as a win. In the Six Nations each team places five matches, so the bonus points could add up to more than a win. A way to remedy this might be to award more points for a win: six for a win and three for a draw is my suggestion.

The first game of the last round yesterday was between Wales and Italy, a game which Italy won to finish 5th. They were unlucky not to beat France earlier in the competition and have played some excellent rugby this year. If they can deal with a marked tendency to fade in the last twenty minutes – as they did yesterday, but managed to hold on – then they will be genuine contenders. Wales had a terrible competition, losing all their games and finishing last. I am reliably informed that “wooden spoon” in Welsh is “llwy bren”. But nil desperandum: the last time Wales got the wooden spoon was in 2003; two years later they did the Grand Slam!

Paráid Lá Fhéile Pádraig i Maigh Nuad

Posted in Biographical, Maynooth with tags , , on March 17, 2024 by telescoper

Lá Fhéile Pádraig sona daoibh go léir!

Today being 17th March, it is St Patrick’s Day, so I decided to make the most of my last day in Not-Barcelona and go watch the festivities. Here are some snaps I took on Straffan Road as the Parade made its way into town. As you can see it was a bit overcast, and it was also a bit breezy, but it wasn’t cold and everyone seemed to be enjoying themselves!

As usual, the bin wagon was the star of the show.

If you want some live action, you can see this on my Instagram:

Academic Publishing: Never Mind the Quality…

Posted in Open Access with tags , , , , , , , , on March 16, 2024 by telescoper

I was interested to see that the latest issue of Private Eye contains a short item about academic publishing:

I’ve heard many stories of this type, with publishers putting pressure on their Editorial Boards to allow more papers to be published. This is undoubtedly motivated by the Gold Open Access model in which authors or their institutions are forced to pay thousands of dollars upfront to publish papers. Since the publisher makes an eye-watering profit on every article, why not publish as many as possible? The recent decision by the Royal Astronomical Society adopt this model is highly likely to have a similar effect there, as its journals will be able to increase revenue at the expense of quality. Under the older subscription-based system, publishers could sell their product to libraries on the basis of quality but they no longer need to do that to make a profit.

The academic publishing industry is perverse enough without adding this obvious incentive to lower editorial standards. There are far too many low quality papers being published already, a situation driven not only by the profiteering of the publishing industry but also by the absurd policies of academia itself which require researchers to churn out huge numbers of papers to get promotion, win research grants, etc.

This part of the academic system is definitely broken. To fix it, academic publishing must be taken out of the hands of commercial publishers and put into the care of research institutions whose libraries are perfectly capable of publishing and curating articles on a non-profit basis. But that won’t be enough: we need also to overhaul how we do research assessment. The principles outlined in the San Francisco Declaration on Research Assessment would be a start.

Cavete Quod Idibus Martiis

Posted in Film, History with tags , , on March 15, 2024 by telescoper

I almost forgot that today is the Ides of March , but I’ve remembered now and it’s not too late a priceless bit of cultural history relevant to such this fateful day. This is from the First Folio Edition of Carry On Cleo, and stars the sublime Kenneth Williams as Julius Caesar delivering one of the funniest lines in the whole Carry On series. The joke may be nearly as old as me, but it’s still a cracker…

And if one old joke isn’t enough for you, here is a Caesar Salad:

Scopus Update

Posted in Open Access with tags , , on March 15, 2024 by telescoper

A couple of months ago I blogged about how the Open Journal of Astrophysics had been accepted for listing on Scopus. The process has turned out to be much slower than I was led to believe and the “technical team” responsible for the indexing required much more help than I’d imagined, so we’re not fully there yet. However, I can confirm that we are in the process. This is an excerpt from the accepted titles list which you can find here:

The Scopus indexation process seems to involve processing every article manually, so it’s possible that there will be some errors. Here is a verbatim excerpt from a recent email from the Scopus team that perhaps illustrates why I lack confidence in the process:

We have activated your journal for Scopus indexation and you will be able to find the content indexed online shortly. The title, however, will take some time to have a source page and you will not be able to view it on source list. If the articles indexed on Scopus exceeds 15, Source Page for your title will be automatically created during Scopus browser update. Post which the title will be discoverable on Scopus source list as well.

I hope this clarifies the situation.

My First Maynooth PhD!

Posted in Maynooth, The Universe and Stuff with tags , , , , , , on March 14, 2024 by telescoper

Today saw the viva voce examination of the first PhD student at Maynooth to have completed their degree under my supervision, although in this case the student started his postgraduate degree under another supervisor and I only took over responsibility when that person retired, a few years ago.

Anyway, I delayed my return to Barcelona so I could be present today. It’s not normal practice for the supervisor of a PhD to be present at the examination of the candidate. The rules allow for it – usually at the request of the student – but the supervisor must remain silent unless and until invited to comment by the examiners. I think it’s a very bad idea for both student and supervisor, and the one example that I can recall of a supervisor attending the PhD examination of his student was a very uncomfortable experience. My presence today was limited to supplying a couple of anticipatory bottles of champagne and then waiting nervously for the examination to finish.

I always feel nervous when a student of mine is having their viva voce examination, probably because I’m a bit protective and such an occasion always brings back painful memories of the similar ordeal I went through thirty-odd years ago. However, this is something a PhD candidate has to go through on their own, a sort of rite of passage during which the supervisor has to stand aside and let them stand up for their own work.

The examination turned out to be quite a long one – about three and a half hours – but ended happily. Unfortunately, I had to leave the celebrations early in order to do yet another Euclid-related Zoom call but when that was over I was able to find the pub to which everyone had adjourned and had a pint there with them. I have a feeling the celebrants might make a night of it tonight, but I’m a bit too tired after recent exertions to join them.

The student’s name, by the way, is Aonghus Hunter-McCabe and the title of the thesis is Differential geometric and general relativistic techniques in non-relativistic laboratory systems. If you’re looking for a postdoc to work in related areas then Aonghus might just be the person you want!

P.S. About a decade ago I did a post on the occasion of the PhD examination of another student of mine, Ian Harrison. I found out recently that Ian now has a permanent position at Cardiff University. Congratulations to him!

Desktop – John J. Ronan

Posted in Poetry with tags , , on March 14, 2024 by telescoper

I’m a bit jetlagged and have a busy day ahead, but fortunately I found this interesting and vaguely relevant poem in an old copy of the TLS last night, so will share it in lieu of a proper post.