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Examination Time in Maynooth

Posted in Barcelona, Education, Maynooth, The Universe and Stuff with tags , , on May 17, 2024 by telescoper

Today ( Friday 17th May) is the first day of the Summer Examination Period in Maynooth. Although I’m not there right now I thought I’d take the opportunity to wish all students the best for their examinations:

You shouldn’t really be relying on luck of course, so here are some tips for the examination period (especially for physics students, but applicable elsewhere).

  1. Try to get a good night’s sleep before the examination and arrive in plenty of time before the start. Spending all night cramming is unlikely to help you do well.
  2. Prepare well in advance so you’re relaxed when the time comes.
  3. 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.
  4. 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. You’re under no obligation to answer the questions in the order they are asked.
  5. Don’t rush! Students often lose marks by making careless errors. In particular, check all your numerical results on your calculator at least twice
  6. Please remember the units!
  7. 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 if you have time.

Meanwhile, in Barcelona, Monday is a public holiday (Pentecost) so I am faced with the prospect of having to endure a long weekend break. Such is life…

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The Radio and Microwave Sky from Juno

Posted in The Universe and Stuff with tags , , , , , , , on May 16, 2024 by telescoper

I found out about an interesting paper by Anderson et al. at a discussion group this morning. The abstract reads:

We present six nearly full-sky maps made from data taken by radiometers on the Juno satellite during its 5-year flight to Jupiter. The maps represent integrated emission over ∼4% passbands spaced approximately in octaves between 600 MHz and 21.9 GHz. Long time-scale offset drifts are removed in all bands, and, for the two lowest frequency bands, gain drifts are also removed from the maps via a self-calibration algorithm similar to the NPIPE pipeline used by the Planck collaboration. We show that, after this solution is applied, residual noise in the maps is consistent with thermal radiometer noise. We verify our map solutions with several consistency tests and end-to-end simulations. We also estimate the level of pixelization noise and polarization leakage via simulations.

arXiv:2405.08388

For those of you unaware about Juno, it is a NASA space mission (launched in 2011) intended to study the planet Jupiter (which it is still doing). On the way there, however, this spacecraft made continuous measurements of the radiation field around it, at radio and microwave frequencies. The work described by Anderson et al. involved turning these observations into maps at a range of frequency; they also studied the polarization properties of the radiation.

The full maps and other relevant data can be downloaded here. Here are some pretty pictures (the grey bits represent the parts of the sky that were not covered; radio emission from our own Galaxy is the most obvious component at low frequencies, but it looks more complicated at higher frequencies).

It’s always fun when data sets are used for something so different from the purpose originally intended, and what has come out of this analysis are rather nice maps of the emission from the Milky Way. These might turn out to be useful for many things, such as foreground removal for extragalactic surveys or studies of our own Galaxy.

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R.I.P. Jim Simons (1938-2024)

Posted in R.I.P., The Universe and Stuff with tags , , , , , on May 13, 2024 by telescoper

I heard yesterday of the death, at the age of 86, of Jim Simons. Jim Simons started out as an academic in the fields of mathematics and mathematical physics. Together with Shiing-Shen Chern he developed the Chern–Simons form, which has been of interest recently in the context of cosmology because of the potential for parity violation, and also contributed to the development of a theoretical framework to combine geometry and topology with quantum field theory. He then moved to into the world of hedge funds, and became a highly successful investor on Wall Street, amassing a huge personal fortune. In later life he turned back to his first loves, however, and set up the Simons Foundation which supports, among many other things, the Simons Observatory and the Flatiron Institute both of which have had, and will no doubt continue to have, an enormous impact in the fields of cosmology and astrophysics. The Simons Foundation has also made large donations to the arXiv.

R.I.P. Jim Simons (1938-2024)

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Night of the Aurora

Posted in Biographical, Maynooth, The Universe and Stuff with tags , , , , , on May 11, 2024 by telescoper

My social media feeds have been buzzing all day with images of last night’s display of the Aurora Borealis (and Australis) resulting from a large solar storm. I saw some great pictures from Ireland, including many from Maynooth and environs. I really liked this one taken from one of the ships of the Irish Naval Service:

I also saw pictures of the Aurora Borealis from the UK (even as far South as the Midlands), USA and as far South in Europe as Marseilles, not to mention New Zealand (Aurora Australis).

It’s not that unusual for the Northern Lights to be visible from Ireland, but it is extremely rare to see them from Catalonia. They were visible last night from Sabadell, just a few km North of Barcelona, though not as far as I know in Barcelona itself. I didn’t see anything, but I was otherwise engaged. The Observatory at Montsec Astronomical Park recorded the strongest level of Auroral activity for 150 years.

Auroral activity seen from Sabadell, picture credit Albert Segura Lorrio

All this reminds me that many moons ago, I once stood directly under an auroral display, in Tromsø (Norway), and I can tell you ever the word “awesome” applied to anything, this was it. The curious thing is that I had the definite feeling that there was a booming and whooshing sound to go with the light show. I wasn’t the only one there who thought they could hear it as well as see it. And I wasn’t drunk either. Well, not very.

Whenever I asked anyone about the sound my questions were dismissed on the grounds that there is no physical mechanism that could produce sound waves at audible frequencies of sufficient power to reach ground level from the altitude at which the light is generated. It must have been psychological, as if the brain wants to add a backing track when it sees something as spectacular as this. However, read at least one researcher is not so sure…

Comments are welcome through the usual box.

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Four New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , on May 11, 2024 by telescoper

It is time yet again for an update of recent activity at the Open Journal of Astrophysics.
This week we have published four papers, which I now present to you. These four take the count in Volume 7 (2024) up to 36 and the total published by OJAp up to 151. I speculated last week that we would probably pass the 150 mark this week, and so we did. We’re still on target to publish around 100 papers this year.
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 “Ephemeris Matching Reveals False Positive Validated and Candidate Planets from the K2 Mission” by Drake A. Lehmann (U. Wisconsin-Madison, USA) and Andrew Vanderburg (MIT, USA). It presents a description and application of a technique for identifying false positives among candidate exoplanets. The paper was published on 7th May 2024, is in the folder marked Earth and Planetary Astrophysics, and can be found 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 “Accuracy requirements on intrinsic alignments for Stage-IV cosmic shear” which is by by Anya Paopiamsap, Natalia Porqueres & David Alonso (Oxford, UK) and Joachim Harnois-Deraps & C. Danielle Leonard (Newcastle, UK). This paper sets about quantifying the permissible level of disagreement between the true intrinsic galaxy alignments and the theoretical models thereof that can be allowed for future Stage-IV cosmic shear surveys. This one is in the folder marked Cosmology and Nongalactic Astrophysics. The paper was published on May 9th 2024 and you can see the overlay here:


The accepted version of this paper can be found on the arXiv here.
The next paper, is in the folder Instrumentation and Methods for Astrophysics and is entitled “Optimal Summary Statistics for X-ray Polarization”. The authors are Jeremy Heyl (Uni. British Columbia, Canada), Denis González-Caniulef (Uni. Toulouse, France) and Ilaria Caiazzo (Caltech, USA). This presents new statistical estimators for use in studies of X-ray polarization, with an analytic discussion of their efficiency. It can be found here and the accepted version can be read on arXiv here. Here is the overlay:

The last paper of this batch is called “B-modes from galaxy cluster alignments in future surveys” and is by Christos Georgiou, Thomas Bakx, Juliard van Donkersgoed and Nora Elisa Chisari, all from Utrecht University in The Netherlands. It presents a discussion of the possible detection of cosmic shear B-modes produced by intrinsic alignments in future galaxy surveys.
Here is the overlay:

You can find the full text for this one on the arXiv here. The primary classification for this one is Cosmology and Nongalactic Astrophysics.
And that ends this week’s update. More next week!

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Publishing Stats for Astrophysics Journals

Posted in Open Access, The Universe and Stuff with tags , , , , , on May 6, 2024 by telescoper

Somebody asked me about this recently so this afternoon while I was paying rapt attention to a Zoom call I was attending I did some quick sums and produced the table below. The request that was made was to give details of total numbers of papers published in the big astronomy and astrophysics journals last year. This is easy relatively easy to do using the excellent NASA/ADS search tool.

Name of JournalNumber of PapersNumber of CitationsAverage citations per paper
MNRAS413125,5406.18
A&A235415,9016.75
ApJ285915,7715.52
ApJL72610,22814.09
ApJS3382,6117.72
OJAp503717.42
Citations to papers published in 2023 (Data from NASA/ADS)

In case you weren’t aware of the standard abbreviations, MNRAS is Monthly Notices of the Royal Astronomical Society and A&A is Astronomy and Astrophysics; ApJ is the Astrophysical Journal, ApJL is the Astrophysical Journal Letters and ApJS is the Astrophysical Journal Supplement Series. The Open Journal of Astrophysics is OJAp.

Anyway, you can see that the big journals published many more papers last year than OJAp but in terms of citations per paper OJAp is doing well. We have a lot of ground to make up if we’re going to be a significant player in the game in terms of sheer quantity of publications, but since we don’t make a profit from APCs we have no reason to lower standards to achieve that.

If you’re interested, the average citations per paper so far this year (i.e. as of 6th May 2024) are: MNRAS (1.84); A&A (1.66); ApJ (2.29); ApJL (2.05), ApJS (2.09) and OJAp (2.90).

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Two New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , , , on May 4, 2024 by telescoper

It’s Saturday morning in Barcelona, and 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 32 and the total published by OJAp up to 147. There’s every chance we will reach 150 next week.

The first paper of the most recent pair – published on  Monday 29th April- is “Supernovae in 2023 (review): possible breakthroughs by late observations” by Noam Soker of Technion in Haifa, Israel. It presents  a discussion of observations of the aftermath of supernovae explosions, such as supernova remnants, and how these may shed light on the explosion mechanism. This one is in the folder marked High-Energy Astrophysical Phenomena.

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 on Thursday 2nd May and has the title “ΛCDM is alive and well” The authors are: Alain Blanchard (Université de Toulouse, France), Jean-Yves Héloret (Université de Toulouse, France), Stéphane Ilíc (Université Paris-Saclay, France), Brahim Lamine (Université de Toulouse, France) and Isaac Tutusaus (Université de Genève, Switzerland). This one, which is in the folder marked Cosmology and NonGalactic Astrophysics, presents a review of  review of the alleged tensions between observations and the standard cosmological model.

I did a post recently relating to a Royal Society Meeting on this topic. The first version of this paper appeared on arXiv about two years ago but the final version is extensively modified.

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.

And that concludes this week’s update. More next week!

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Masters in Theoretical Physics & Mathematics at Maynooth

Posted in Education, Maynooth, The Universe and Stuff with tags , , on April 30, 2024 by telescoper

I may not be in Maynooth this academic year but that doesn’t stop me using the medium of this blog to advertise the fact that the MSc in Theoretical Physics & Mathematics is open to applications for entry in September.

This postgraduate course is run jointly between the Departments of Theoretical Physics and Mathematics & Statistics, with each contributing about half the material. The duration is one calendar year (full-time) or two years (part-time) and consists of 90 credits in the European Credit Transfer System (ECTS). This is split into 60 credits of taught material (split roughly 50-50 between Theoretical Physics and Mathematics) and a research project of 30 credits, supervised by a member of staff in a relevant area from either Department.

Here is an instagram post advertising the course:

This course is a kind of follow-up to the existing undergraduate BSc Theoretical Physics & Mathematics at Maynooth, also run jointly. We think the postgraduate course will appeal to many of the students on that programme who wish to continue their education to postgraduate level, though applications are very welcome from suitably qualified candidates who did their first degree elsewhere.

There is a central system for postgraduate applications in Ireland (called PAC) that is similar to the undergraduate admissions system. You will need to apply online via PAC after the following the instructions here. The requisite PAC code for the full-time version of the course is MHQ56.

The closing date for applications is 30th June 2024.

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Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , on April 27, 2024 by telescoper

It’s time for the usual  Saturday roundup of 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 30 and the total published by OJAp up to 145.

First one up is “Baryonic Imprints on DM Halos: the concentration-mass relation and its dependence on halo and galaxy properties” .  The authors, Mufan Shao and Dhayaa Anbajagane of the University of Chicago, USA, use  a non-linear model informed by simulations to study the imprint of galaxy formation physics on the concentration-mass relationship using various different choices of halo selection criteria. This one is in the folder marked Astrophysics of Galaxies and was published on 24th April 2024.

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

 

You can read the paper directly on arXiv here.

The second paper to announce is “Variability in SSTc2d J163134.1-240100, a brown dwarf with quasi-spherical mass loss” which describes a search for variability in a brown dwarf star known to be losing mass and the implications of the lack thereof for the reason for the outflow therefrom. The authors are Aleks Scholz (St Andrews, UK),  Koraljka Muzic (Lisbon, Portugal), Victor Almendros-Abad (Palermo, Italy), Antonella Natta (DIAS, Ireland), Dary Ruiz-Rodriguez (NRAO, USA), Lucas Cieza (Uni. Diego Portales, Chile), Cristina Rodriguez-Lopez (IAA-CSIC, Granada, Spain)

This one is in the folder Solar and Stellar Astrophysics and was also published on 24th April 2024. The overlay looks like this:

 

You can read this paper directly on the arXiv here.

The last paper of this batch, also in the folder marked Astrophysics of Galaxies, is  entitled “MAGICS I. The First Few Orbits Encode the Fate of Seed Massive Black Hole Pairs”  and is a computational study of the process by which massive black holes are formed by merging smaller seed black holes. It was published on April 26th 2024 (i.e. yesterday). The authors are: Nianyi Chen, Diptajyoti Mukherjee and Tiziana Di Matteo (all Carnegie Mellon University); Yueying Ni (Harvard); Simeon Bird (University of California, Riverside); and Rupert Croft (Carnegie Mellon University). All authors are based in the USA.

Here is a screengrab of the overlay:

 

To read the accepted version of this on the arXiv please go here.
That’s all for now. More news in a week or so!

 

 

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.Astronomy

Posted in Barcelona, Euclid, The Universe and Stuff with tags , , , , , , , , on April 24, 2024 by telescoper

So here I am at the European Space Astronomy Centre (ESAC) just outside Madrid for a conference called .Astronomy 13. It is (obviously) the thirteenth such conference but the first that I have attended. I’m giving a plenary talk in half-an-hour or so. I travelled from Barcelona by train yesterday evening, which was a comfortable and uneventful trip, the (approximately) 504 km from Barcelona to Madrid Atocha station taking about 2 hours and 30 minutes that cost about 30 euros. I stayed overnight in Madrid and took a shuttle bus from to ESAC. The only glitch in my travels so far was that I got on the Metro Line 6 (the equivalent of the Circle Line), but chose the wrong platform and went the long way round. I still got there in time to get the shuttle.

Incidentally, ESAC hosts the Euclid Science Operations Centre (SOC) which plays a central role in the processing of data from Euclid and is also responsible for the development and operations of the Euclid Archive from which data will be distributed to the global astronomical community.

UPDATE: Back in Barcelona. The return by train was just as smooth an uneventful as the outbound journey, and in fact arrived back about five minutes ahead of schedule. Thanks to the organizers for inviting me – I’m sorry I couldn’t stay for longer as I like the idea of the .Astronomy meetings. Perhaps we should have one in Ireland sometime?

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